WO2010019496A1 - Flexible thin film photovoltaic modules and manufacturing the same - Google Patents

Flexible thin film photovoltaic modules and manufacturing the same Download PDF

Info

Publication number
WO2010019496A1
WO2010019496A1 PCT/US2009/053265 US2009053265W WO2010019496A1 WO 2010019496 A1 WO2010019496 A1 WO 2010019496A1 US 2009053265 W US2009053265 W US 2009053265W WO 2010019496 A1 WO2010019496 A1 WO 2010019496A1
Authority
WO
WIPO (PCT)
Prior art keywords
solar cell
sealant
module
protective sheet
divider
Prior art date
Application number
PCT/US2009/053265
Other languages
French (fr)
Inventor
Bulent M. Basol
Original Assignee
Solopower, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US12/189,627 external-priority patent/US8207440B2/en
Priority claimed from US12/250,507 external-priority patent/US20100031996A1/en
Application filed by Solopower, Inc. filed Critical Solopower, Inc.
Priority to EP09807121A priority Critical patent/EP2319090A1/en
Publication of WO2010019496A1 publication Critical patent/WO2010019496A1/en

Links

Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02SGENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S30/00Structural details of PV modules other than those related to light conversion
    • H02S30/20Collapsible or foldable PV modules
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02Details
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042PV modules or arrays of single PV cells
    • H01L31/048Encapsulation of modules
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042PV modules or arrays of single PV cells
    • H01L31/05Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells
    • H01L31/0504Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells specially adapted for series or parallel connection of solar cells in a module
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy

Definitions

  • the aspects and advantages of the present inventions generally relate to apparatus and methods of photovoltaic or solar module design and fabrication and, more particularly, to roll-to-roll or continuous packaging techniques for flexible modules employing thin film solar cells.
  • Solar cells are photovoltaic devices that convert sunlight directly into electrical power.
  • the most common solar cell material is silicon, which is in the form of single or polycrystalline wafers.
  • silicon-based solar cells the cost of electricity generated using silicon-based solar cells is higher than the cost of electricity generated by the more traditional methods. Therefore, since early 1970's there has been an effort to reduce cost of solar cells for terrestrial use.
  • One way of reducing the cost of solar cells is to develop low-cost thin film growth techniques that can deposit solar-cell- quality absorber materials on large area substrates and to fabricate these devices using high- throughput, low-cost methods.
  • Group IBIIIAVIA compound semiconductors comprising some of the Group IB (Cu,
  • Cu(In,Ga) means all compositions from CuIn to CuGa.
  • Cu(In,Ga)(S,Se) 2 means the whole family of compounds with Ga/(Ga+In) molar ratio varying from 0 to 1, and Se/(Se+S) molar ratio varying from 0 to 1.
  • FIG. 1 The structure of a conventional Group EB IIIA VIA compound photovoltaic cell such as a Cu(In,Ga,Al)(S,Se,Te) 2 thin film solar cell is shown in Figure 1.
  • a photovoltaic cell 10 is fabricated on a substrate 11, such as a sheet of glass, a sheet of metal, an insulating foil or web, or a conductive foil or web.
  • An absorber film 12, which includes a material in the family of Cu(In,Ga,Al)(S,Se,Te) 2 is grown over a conductive layer 13 or contact layer, which is previously deposited on the substrate 11 and which acts as the electrical contact to the device.
  • the substrate 11 and the conductive layer 13 form a base 20 on which the absorber film 12 is formed.
  • Various conductive layers comprising Mo, Ta, W, Ti, and their nitrides have been used in the solar cell structure of Figure 1. If the substrate itself is a properly selected conductive material, it is possible not to use the conductive layer 13, since the substrate 11 may then be used as the ohmic contact to the device.
  • a transparent layer 14 such as a CdS, ZnO, CdS/ZnO or CdS/ZnO/ITO stack is formed on the absorber film 12. Radiation 15 enters the device through the transparent layer 14.
  • Metallic grids may also be deposited over the transparent layer 14 to reduce the effective series resistance of the device.
  • the preferred electrical type of the absorber film 12 is p-type, and the preferred electrical type of the transparent layer 14 is n-type. However, an n-type absorber and a p-type window layer can also be utilized.
  • the preferred device structure of Figure 1 is called a "substrate-type" structure.
  • a "superstrate-type” structure can also be constructed by depositing a transparent conductive layer on a transparent superstrate such as glass or transparent polymeric foil, and then depositing the Cu(In 5 Ga, Al)(S, Se 5 Te) 2 absorber film, and finally forming an ohmic contact to the device by a conductive layer. In this superstrate structure light enters the device from the transparent superstrate side.
  • the solar cells are deposited or formed on an insulating substrate such as glass that also serves as a back protective sheet or a front protective sheet, depending upon whether the device is "substrate-type" or "superstrate-type", respectively.
  • the solar cells are electrically interconnected as they are deposited on the substrate.
  • the solar cells are monolithically integrated on the single- piece substrate as they are formed.
  • These modules are monolithically integrated structures.
  • the superstrate is glass which also is the front protective sheet for the monolithically integrated module.
  • the substrate is glass or polyimide and serves as the back protective sheet for the monolithically integrated module.
  • an encapsulant is placed over the integrated module structure and a protective sheet is attached to the encapsulant.
  • An edge seal may also be formed along the edge of the module to prevent water vapor or liquid transmission through the edge into the monolithically integrated module structure.
  • the solar cells are not deposited or formed on the protective sheet. They are separately manufactured and then the manufactured solar cells are electrically interconnected by stringing them or shingling them to form solar cell strings. In the stringing or shingling process, the (+) terminal of one cell is typically electrically connected to the (-) terminal of the adjacent device.
  • the substrate 11 is conductive such as a metallic foil, then the substrate, which is the bottom contact of the cell, constitutes the (+) terminal of the device.
  • the metallic grid (not shown) deposited on the transparent layer 14 is the top contact of the device and constitutes the (-) terminal of the cell.
  • individual cells are placed in a staggered manner so that a bottom surface of one cell, i.e. the (+) terminal, makes direct physical and electrical contact to a top surface, i.e. the (-) terminal, of an adjacent cell. Therefore, there is no gap between two shingled cells.
  • Stringing is typically done by placing the cells side by side with a small gap between them and using conductive wires or ribbons that connect the (+) terminal of one cell to the (-) terminal of an adjacent cell.
  • Solar cell strings obtained by stringing or shingling individual solar cells are interconnected to form circuits.
  • Circuits may then be packaged in protective packages to form modules.
  • Each module typically includes a plurality of strings of solar cells which are electrically connected to one another.
  • the solar modules are constructed using various packaging materials to mechanically support and protect the solar cells in them against mechanical damage.
  • the most common packaging technology involves lamination of circuits in transparent encapsulants.
  • the electrically interconnected solar cells are covered with a transparent and flexible encapsulant layer which fills any hollow space among the cells and tightly seals them into a module structure, preferably covering both of their surfaces.
  • a variety of materials are used as encapsulants, for packaging solar cell modules, such as ethylene vinyl acetate copolymer (EVA), thermoplastic polyurethanes (TPU), and silicones.
  • the protective shell includes a front protective sheet and a back protective sheet and optionally an edge sealant that is at the periphery of the module structure (see for example, published application WO/2003/050891, "Sealed Thin Film PV Modules").
  • the top protective sheet is typically glass which is water impermeable.
  • the back protective sheet may be a sheet of glass or a polymeric sheet such as TEDLAR ® (a product of DuPont).
  • the back protective polymeric sheet may or may not have a moisture barrier layer in its structure such as a metallic film like an aluminum film. Light enters the module through the front protective sheet.
  • the edge sealant which is presently used in thin film CdTe modules with glass/glass structure, is a moisture barrier material that may be in the form of a viscous fluid which may be dispensed from a nozzle to the peripheral edge of the module structure or it may be in the form of a tape which may be applied to the peripheral edge of the module structure.
  • the edge sealant in Si-based modules is not between the top and bottom protective sheets but rather in the frame which is attached to the edge of the module. Moisture barrier characteristics of edge seals used for Si-based modules are not adequate for CIGS based modules as will be discussed later.
  • Flexible module structures may be constructed using flexible CIGS or amorphous Si solar cells.
  • Flexible modules are light weight, and unlike the standard glass based Si solar modules, are un-breakable. Therefore, packaging and transportation costs for flexible modules are much lower.
  • packaging of flexible structures are more challenging.
  • Glass handling equipment used in glass based PV module manufacturing are fully developed by many equipment suppliers. Handling of flexible sheets cannot be carried out using such standard equipment.
  • the flexible sheets that constitute the various layers in the flexible module structure may be cut into sizes that are close to the desired area of the module, and then the standard module encapsulation procedures may be carried out by handling and moving these pieces around.
  • a more manufacturing friendly approach for flexible module manufacturing is needed to increase the reliability of such modules and reduce their manufacturing cost.
  • an apparatus comprising: a continuous flexible sheet for use in fabricating flexible solar cell modules, the continuous flexible sheet including: a front surface and a back surface, one of the front surface and the back surface including at least two moisture barrier regions and a separation region, wherein the separation region surrounds each moisture barrier region and physically separates adjacent moisture barrier regions; and a moisture barrier layer formed on each of the moisture barrier regions but not on the separation region.
  • a monolithically integrated multi-module power supply including moisture barrier layers covering each of the ceilings of each of a plurality of sealed chambers that hold two solar cells that are electrically interconnected.
  • described methods of manufacturing a photovoltaic module BRIEF DESCRIPTION OF THE DRAWINGS
  • Figure 1 is a schematic view a thin film solar cell
  • Figure 2A is a schematic cross sectional view of a flexible thin film solar module
  • Figure 2B is a schematic top view of the module of Figure 2A;
  • Figures 3A-3F are schematic views of an embodiment of manufacturing of a continuous packaging structure of the present invention including a plurality of module structures;
  • Figures 4A-4B are schematic views of transforming the continuous packaging structure into a continuous multi-module power device including a plurality of solar modules;
  • Figure 5 is a schematic side view of a solar module of the present invention.
  • Figures 6A-6B are schematic views of an embodiment of manufacturing monolithically integrated multi-module power supplies.
  • Figure 7 is a schematic view of a roll to roll system to manufacture flexible photovoltaic modules of the present invention.
  • Figure 8 exemplifies a monolithically integrated multi-module power supply 600 having electrical leads with the first configuration.
  • Figure 9 exemplifies a monolithically integrated multi-module power supply 700 having electrical leads with the second configuration due to the odd numbered row of solar cells.
  • Figure 10 exemplifies a monolithically integrated multi-module power supply 800 having electrical leads with the first configuration due to the even numbered row of solar cells.
  • Figure 11 exemplifies a monolithically integrated multi-module power supply 900 having electrical leads with the second configuration due to the odd numbered row of solar cells.
  • Figure 12A is a schematic view of a solar cell module according to one embodiment
  • Figure 12B is a schematic cross sectional view of the solar cell module shown in
  • Figures 13A-13B show a process of manufacturing another embodiment of a continuous packaging structure
  • Figure 13C shows the completed structure of the continuous packaging structure of the embodiment made according to the process described in Figures 13A-13B;
  • Figure 14A is a schematic view of an embodiment of a solar cell module;
  • Figure 14B is a schematic cross sectional view of the solar cell module shown in
  • Figure 15 is a schematic view showing the components of the solar cell module during manufacturing
  • FIGS 16 and 17 are schematic views of various embodiments of the solar cell module
  • Figure 18 is a module design
  • Figure 19 is a solar cell used in the module design of Figure 18.
  • the preferred embodiments described herein provide methods of manufacturing flexible photovoltaic modules employing thin film Group IBIIIAVIA compound solar cells.
  • the modules each include a moisture resistant protective shell within which flexible interconnected solar cells or cell strings are packaged and protected.
  • the protective shell comprises a moisture barrier top protective sheet through which the light may enter the module, a moisture barrier bottom protective sheet, a support material or encapsulant covering at least one of a front side and a back side of each cell or cell string.
  • the support material may preferably be used to fully encapsulate each solar cell and each string, top and bottom.
  • the protective shell additionally comprises a moisture sealant that is placed between the top protective sheet and the bottom protective sheet along the circumference of the module and forms a barrier to moisture passage from outside into the protective shell from the edge area along the circumference of the module.
  • the top protective sheet and the bottom protective sheet of the present module have a moisture transmission rate of less than 10 ⁇ 3 gm/m 2 /day, preferably less than 5XlO "4 gm/m 2 /day.
  • the present invention specifically provides a continuous manufacturing method to form a continuous packaging structure including a plurality of solar cell modules on elongated protective sheet bases.
  • a moisture barrier frame is first applied on the elongated protective sheet having pre designated module areas.
  • the moisture barrier frame is a moisture sealant (with transmission rate of ⁇ 10 ⁇ 3 gm/m 2 /day, or moisture breakthrough time of at least 20 years through the seal) which may be applied on the elongated protective sheet as a tape, gel or liquid.
  • the walls of the moisture barrier frame surround the borders of each of the plurality of designated module areas and form a plurality of cavities defined by the walls of the moisture barrier frame and the designated module areas.
  • the walls of the moisture barrier frame include side walls and divider walls.
  • the side walls may form side walls of the plurality of cavities.
  • Divider walls separate individual cavities from one another by forming adjoining walls between two cavities.
  • Solar cell strings are placed into each of the cavities and supported by a support material filling each cavity. The strings in the adjacent cavities are not electrically connected to one another.
  • a pair of power output wires or terminals is extended from the strings to the outside through the side walls.
  • a second support material is placed over the strings and a second elongated protective sheet is placed over the support material and the moisture barrier frame to enclose the plurality of cavities, thereby forming the plurality of solar cell modules.
  • the continuous packaging structure is completed in a continuous manner, it is laminated to form a continuous multi-module device including a plurality of laminated solar cell modules.
  • the continuous multi-module device can be cut into sections including a desired number of laminated solar cell modules that can be used in solar energy production applications.
  • the laminated solar cell modules in each section can also be advantageously electrically connected by connecting power output wires that outwardly extend from each solar cell module. If any solar cell module malfunctions during the application, that malfunctioning portion may be easily removed and the remaining modules are reconnected for the system to continue performing. Such removal may be only electrical in nature, i.e. the failed module is electrically taken out of the circuit by simply disconnecting its power output wires. It is also possible to physically remove the failed module by cutting it out along the two divider walls on its two sides without negatively impacting the moisture sealant nature of the divider walls.
  • a manufacturing process of the modules may be performed by stacking various components of the modules on a continuous elongated protective sheet provided in a roll-to roll manner.
  • the manufacturing process may be performed on a continuous flexible module base, comprising a transparent elongated sheet with moisture barrier layer sections deposited onto a back surface of the transparent elongated protective sheet.
  • the moisture barrier layer sections are physically separated from one another by a separation region, also referred to as a moisture sealant region, which fully surrounds the moisture barrier layer sections and does not contain any moisture barrier layer.
  • a moisture barrier frame is applied onto the separation region and the walls of the moisture barrier frame surround each of the moisture barrier layer sections and form a plurality of cavities defined by the walls of the moisture barrier frame and the moisture barrier layer sections.
  • Figure 2A shows the cross section of an exemplary flexible module 1.
  • Figure 2B is a top view of the same module.
  • the exemplary flexible module 1 is an overly simplified one comprising only three cells 2a, 2b and 2c forming a string. In reality, many more cells and cell strings are used.
  • the three cells 2a, 2b and 2c are interconnected using conductor wires 3 to form the cell string 2AA and terminal wires 4 extend to outside the perimeter formed by the top protective sheet 7 and the bottom protective sheet 8.
  • the wires 4 can be extended to outside the module by cutting the continuous packaging structure along line A-A as shown in Figure 2B, and then removing material 9a that exists within the area between lines Bl and B2, thereby leaving the wires 4 extending outside the perimeter of the module.
  • wires 4 may be joined together within the package and then only a single wire (not shown) can extend outside the module. It is also possible to take the terminal wire from the back side of the module 1 as shown in the case of terminal wire 5. It is, however, preferable to bring the terminal wires through the moisture sealant 9 in a sealed manner.
  • the cell string 2AA is covered with a top support material or encapsulant 6a and a bottom encapsulant 6b.
  • the top encapsulant 6a and the bottom encapsulant 6b are typically the same material but they may be two different materials that melt together and surround the cell string 2AA top and bottom.
  • the top protective sheet 7 which is transparent and resistive to moisture permeation
  • the bottom protective sheet 8 which is resistive to moisture permeation
  • a moisture sealant 9 along the edge of the module form a protective shell 100, which is filled with the cell string 2AA, the top encapsulant 6a and the bottom encapsulant 6b. It should be noted that the thicknesses of the components shown in the figures are not to scale.
  • a flexible module structure such as the one shown in Figures 2 A and 2B, as well as a modification of that flexible module structure as it relates to the terminal wires that extend outside a perimeter of the flexible module structure through the moisture sealant, may be fabricated in a continuous manner using continuous manufacturing techniques such as in-line or roll-to-roll process.
  • an initial component such as an elongated top protective sheet 200A may be first provided in a continuous or stepwise manner from a supply roll of a roll-to-roll module manufacturing system, and travels through a number of process stations, which add other components of the modules over the elongated protective sheet to manufacture a continuous packaging structure including a plurality of solar cell modules.
  • Resulting continuous multi-module device may then be rolled onto a receiving spool to form a roll, or the continuous multi-module device may be cut into smaller sections each containing one or more modules as will be explained later.
  • FIG 3 A shows a first step of the process during which a section of the top elongated protective sheet 200A having a back surface 202 and two edges 203 is provided.
  • the width of the elongated protective sheet may typically be in the range of 30-300 cm.
  • the top elongated protective sheet forms the front side or the light receiving side of the modules that will be manufactured using the process of the invention.
  • a moisture sealant 204 is applied on the back surface 202 of the top elongated protective sheet 200A.
  • the moisture sealant 204 surrounds module spaces 208 and is preferably deposited along the two edges 203 of the protective sheet 200A and between the module spaces 208.
  • the portion of the moisture sealant 204 deposited along the edges 203 A of the top elongated protective sheet 200A will be called side sealant 206 or side wall and the portion of the moisture sealant disposed between the module spaces 208 or ends of the module spaces will be called divider sealant 207 or divider wall.
  • the moisture sealant 204 may be in the form of a tape or it may be a viscous liquid that may be dispensed onto the back surface 202 of the top elongated protective sheet 200A.
  • the module spaces 208 are the spaces on the back surface 202 that are bordered or surrounded by the moisture sealant 204 applied on the back surface 202.
  • the side walls 206 and the divider walls 207 of the moisture sealant 204 form a plurality of cavities 209 on the top elongated protective sheet 200A.
  • Each cavity 209 may be defined by one module space 208 and the side walls 206 and divider walls 207 that surround that module space 208.
  • the moisture sealant 204 may be formed as a single piece continuous frame including the side walls and the divider walls which are shaped and dimensioned according to the desired solar cell module shape and size. When such frame is applied on the back surface 202 of the top elongated protective sheet 200A, it forms the cavities 209.
  • solar cell strings 212 include solar cells 213 that are electrically interconnected.
  • the strings 212 in each of the cavities 209 are not electrically interconnected to one another, i.e. there is no electrical connection between cells in one cavity with the cells in an adjacent cavity. It is, however, possible to have such interconnections as described in the US patent application with serial number 12/189627 entitled “photovoltaic modules with improved reliability” filed August 11, 2008, in which a fabricated module may comprise two or more sealed compartments (e.g. the cavities 209) each containing solar cell strings.
  • back side 215B or base of the solar cells 213 are covered with another layer of support material 210.
  • a back elongated protective sheet 200B is placed on the moisture sealant 204 and over the support material 210 to complete the assembly of the components of a continuous packaging structure 300 having a plurality of solar cell module structures 302.
  • the continuous packaging structure 300 is processed in a laminator, such as a roll laminator with rollers 450 to transform it to a continuous multi-module device 300A having a plurality of solar cell modules 302A.
  • a laminator such as a roll laminator with rollers 450 to transform it to a continuous multi-module device 300A having a plurality of solar cell modules 302A.
  • the support material 210 in each module structure 302 melts and adheres to the solar cell strings 212 and to the top and back elongated protective sheets 200A and 200B.
  • the moisture sealant 204 also melts and adheres to the top and back elongated protective sheets 200A and 200B.
  • Figure 4B shows in top view the continuous multi-module device 300A having the solar cell modules 302A after the continuous packaging structure 300 is processed in the laminator.
  • support materials that do not involve chemical cross linking are preferred to support materials that involve cross linking, such as EVA.
  • the preferred support materials include silicones and thermo plastic materials that may have melting temperatures in the range of 90-150 C.
  • the moisture sealant 204 may also be a thermo plastic that can be melted easily in a roll laminator where pressure and heat may be applied to the module structure in presence or in absence of vacuum. It should be noted that the sealant material 204 may be dispensed in liquid form or it may be in the form of an adhesive tape that adheres on the back surface 202 of the top elongated protective sheet 200A.
  • the silicone may be dispensed onto each module area defined by the cavity 209 formed by the back surface 202 and the sealant material 204. Therefore, the back surface 202 and the sealant material 204 acts like a container to contain the liquid silicone support material 210.
  • the silicone support material 210 may be partially cured before the cell string is placed onto it (see Figures 3D and 3E) so that the cell string does not sink into the liquid and touch the back surface 202 of the top elongated protective sheet 200A.
  • a series of magnets may be used under the top elongated protective sheet 200A. These magnets pull the cell string towards the top elongated protective sheet 200A and keep them flat against the semi-cured front support material for CIGS solar cells fabricated on magnetic stainless steel foils such as Grade 430 stainless steel. With the magnets in place, the back support silicon material may be dispensed over the cell strings to cover the back side of the cells. With the magnets still in place, the silicone may be heated to be partially or fully cured. This way the cells may be trapped in between two layers of partially or fully cured silicone layers.
  • the magnets may be removed, the back elongated protective sheet 200B may be placed on the moisture sealant 204 and the support material 210 to complete the formation of a continuous packaging structure 300 including a plurality of module structures. Partial curing of silicone may be achieved at a temperature range of 60-100 0 C.
  • the divider sealants 207 between the module structures 302 may have small cuts or holes so that as the continuous packaging structure 300 is laminated any air within a particular module structure 302, as it is transformed into a module between the rollers 450, passes into the next module structure through the uncured divider sealant between the two module structures. Since the next module is not laminated yet and thereby not sealed, entrapped air is released from this module structure and the divider sealant 207 with cuts or holes melts and heals these cuts and holes.
  • the roll lamination may be carried out in a vacuum environment with pressure values in the order of milli-Torrs.
  • Such vacuum levels can be obtained by building separately pumped chambers through which the continuous packaging structure 300 passes through to arrive to the chamber where the roll lamination process is carried out.
  • the continuous packaging structure may enter a first chamber through a narrow slit and then go in and out a number of chambers through narrow slits before arriving into the roll lamination chamber and then travel through several other chambers before exiting the system through a last chamber.
  • This way the pressure may be changed from near atmospheric pressure (760 Torr) in the first and last chambers to a much lower value (such as 100 mTorr) in the lamination chamber.
  • FIG 4B shows the continuous multi-module device 300A after the roll lamination process in top view wherein the light receiving side of the solar cells 213 is toward the paper plane.
  • the continuous multi-module device 300A may be rolled into a receiving roll (not shown) with the electrical leads 214 or terminals of each module in the multi-module device protruding from the side of the receiving roll. This way the terminals do not interfere with the rolling process.
  • the roll may be shipped for further processing or installation in the field.
  • Figure 4B shows the continuous multi- module device 300A obtained after the lamination and sealing process.
  • Each of the modules 302A in this multi-module device is sealed against moisture transmission from outside environment into the module structure where the solar cell strings 212 are encapsulated.
  • the continuous process described above is very versatile. Once the continuous multi- module device is formed, this device may be used in a variety of ways. In one approach the continuous multi-module packaging device is cut into individual modules 302A along the dotted cut lines 'A' which are within the divider walls as shown in Figure 4B, producing completely separate and sealed individual modules.
  • the electrical leads 214 of each module 302A are on the side and does not get affected or cut by this process and the integrity of the moisture sealant 204 is not compromised anywhere along the perimeter of each module. Having electrical leads 214 come out the side along at least one of the two long edges 203 of the continuous multi-module device 302A also maximizes the active area of each module while keeping the integrity of the moisture sealant 204.
  • the continuous multi-module device may be used to form monolithically integrated multi-module power supplies comprising two or more electrically interconnected modules on a common, uncut substrate or superstrate as will be described more fully below.
  • Figure 5 shows in side view an individual module 302A that is manufactured using the process of the present invention by cutting and separating each of the modules 302A from the continuous multi-module device 300A as shown in Figure 4B.
  • the solar cell string 212 is coated with the support material 210 and disposed between a top protective sheet 303 A and a bottom protective sheet 3O3B.
  • the top protective sheet 3O3A and the bottom protective sheet 3O3B are portions of the top and bottom elongated protective sheets 200A and 200B.
  • the moisture sealant 204 extends between the protective sheets 303 A and 300B and seals the perimeter of the module.
  • each solar cell 213 includes the front portion 215A or light receiving portion and the back portion 215B or base.
  • sun light enters the module through the top protective sheet 303 A and arrives at the front portion 215A of the solar cells through the support material 210.
  • the base 215B includes a substrate and a contact layer formed on the substrate.
  • a preferred substrate material may be a metallic material such as stainless steel, aluminum or the like.
  • An exemplary contact layer material may be molybdenum.
  • the front portion 215A of the solar cells may include an absorber layer 305, such as a CIGS absorber layer which is formed on the contact layer, and a transparent layer 306, such as a buffer-layer/ZnO stack, formed on the absorber layer.
  • An exemplary buffer layer may be a (Cd,Zn)S layer.
  • Conductive fingers 308 may be formed over the transparent layer.
  • Conductive leads 310 electrically connect the substrate or the contact layer of one of the solar cells to the transparent layer of the next solar cell.
  • the solar cells may be interconnected using any other method known in the field such as shingling.
  • the front protective sheet 200A may be a transparent flexible polymer film such as
  • the front protective sheet 200A comprises a transparent moisture barrier coating which may comprise transparent inorganic materials such as alumina, alumina silicates, silicates, nitrides etc. Examples of such coatings may be found in the literature (see for example, L. Olsen et al., "Barrier coatings for CIGSS and CdTe cells", Proc. 31 st IEEE PV Specialists Conf., p.327, 2005).
  • TEDLAR ® and TEFZEL ® are brand names of fluoropolymer materials from DuPont.
  • TEDLAR ® is polyvinyl fluoride (PVF), and TEFZEL ® is ethylene tetrafluoroethylene (ETFE) fluoropolymer.
  • the back protective sheet 200B may be a polymeric sheet such as TEDLAR ® , or another polymeric material which may or may not be transparent.
  • the back protective sheet may comprise stacked sheets comprising various material combinations such as metallic films (like Aluminum) as moisture barrier.
  • one advantage of the present invention is its versatility. Instead of cutting and separating each of the modules 302A from the continuous multi-module device 300A shown in Figure 4B, the cutting operation may be performed to form monolithically integrated multi-module power supplies with power ratings much in excess of what is the norm today. Typical high wattage modules in the market have power ratings in the range of 2OO-3OOW. These are structures fabricated using standard methods by interconnecting all solar cells and strings within the module structure. With the light weight and flexible structures of the present invention it is feasible to construct monolithically integrated multi-module power supplies with ratings of 600W and over and even with power ratings of over 1000 W.
  • a roll of a flexible and light weight power generator with multi kW rating on a single substrate can enable new applications in large scale solar power fields. It should be noted that, using the teachings of the present inventions it is possible to build a single module of multi kW rating (such as 2000-5000 W), the single module having one moisture sealant in the form of a moisture barrier frame around its perimeter (see, for example, Figure 2A). However, manufacturing monolithically integrated multi-module power supplies comprising many individual modules each having its own moisture impermeable or moisture resistant structure has many advantages. One advantage is better reliability in such multi-module devices.
  • the continuous multi-module device may be cut to include 5-10 modules and therefore provide a monolithically integrated multi-module power supply with a rating in the range of, for example, 500-2000 W.
  • monolithically integrated multi- module power supplies with power ratings of 1000-20000 W or higher may be employed. The important point is that all of these products can be manufactured from the same manufacturing line by just changing the steps of cutting. Presence of divider sealants between unit modules makes this possible. If divider sealants were not present, long and continuous module structures could not be cut into smaller units and be employed since moisture entering through the cut edges would limit the life of the cut modules or multi-module structures to much less than 20 years.
  • CIGS modules without a proper edge sealant would have a life of only a few years before loosing almost 50% of their power rating.
  • Certain advantages of the present invention may be demonstrated by an exemplary continuous multi-module device 500 shown in Figure 6A, which may be manufactured using the process of the present invention described above.
  • the continuous multi-module device 500, including solar cell modules 502A-502J, shown in Figure 6A may be a portion of a longer continuous structure.
  • Each module includes a solar cell string 512 having interconnected solar cells
  • each module 514 or output wires from each module are positioned along the side of the continuous multi-module device 500 as in the manner shown in Figure 6A.
  • the modules are separated from one another by divider walls 503 of the moisture sealant.
  • output wires 514 are interconnected to provide a combined power output from the modules 502A-502E of the section 504.
  • the power rating of each module is IOOW and if the cut section contains 10 modules that are interconnected, the resulting monolithically integrated multi-module power supply is a continuous, single piece 1000 W supply. If the cut section contains 20 modules a 2000W power supply would be obtained.
  • the interconnection between modules of the monolithically integrated multi-module power supply may be a series interconnection where the (+) terminal of each module is connected to a (-) terminal of an adjacent module. It should be noted that individual modules in the monolithically integrated multi-module power supply may also be interconnected in parallel mode.
  • the monolithically integrated multi-module power supply design of Figure 6B provides advantage for deployment in the field.
  • One advantage is the simplicity of installing a flexible, single piece, high-power power supply in the field. Elimination of handling many individual modules, elimination of many individual installation structures are some of the advantages.
  • Another advantage is the ease of eliminating a malfunctioning module in the monolithically integrated multi-module power supply. This is possible because the inter-module interconnection terminals are outside and accessible. In section 504, for example, if the module 502 malfunctions, instead of discarding the whole section 504, the module 502B would be taken out of the circuitry by disconnecting its wires and the remaining modules 502A, 502C, 502D and 502E would be left interconnected and thus continue providing full power.
  • Bypass diodes and other balance of system components may also be connected to the monolithically integrated multi-module power supply terminals.
  • the cell strings in each module are shown to be parallel to the long edge of the monolithically integrated multi-module power supply shown in Figures 6A and 6B, cell strings may actually be placed in different directions in the module structure. For example, by placing cell strings perpendicular to the long edge of the monolithically integrated multi-module power supply one can reduce the length of each module (defined by the distance between the divider sealants or walls) compared to its width. This way the length of the wires used to interconnect the adjacent modules would be minimized to save cost and power loss in the interconnection wires and other hardware.
  • FIG. 7 shows a roll to roll system 400 to manufacture the continuous multi-module device 300A shown in Figures 3A-4B.
  • the system 400 includes a process station 402 including a number of process units 404A-404F to perform above described process steps as the top protection layer 200A is supplied from the supply roll 405A and advanced through the process station 402.
  • the continuous packaging structure 300 is picked up and wrapped around the receiving roll 405B.
  • the receiving roll 405B is taken into a cutting station to cut the continuous packaging structure 300A.
  • the laminated continuous packaging structure 300 may be directly advanced into a cutting station and cut into individual modules or into monolithically integrated multi-module power supplies.
  • a first configuration one particular configuration of a continuous multi module device with the electrical leads or terminals of each module extending from one side of the continuous multi-module device
  • a second particular configuration will refer to the electrical leads extending from both sides of a continuous multi-module device or a monolithically integrated multi-module power supply.
  • the number and the relative distribution of the solar cells in each module may help to pre-determine whether the monolithically integrated multi- module power supply to be manufactured may have the first configuration or the second configuration.
  • positive and negative electrical leads of each module are located at the same side of the monolithically integrated multi-module power supply such that a positive electrical lead of one of the modules is preferably placed next to a negative electrical lead of an adjacent module so that they can be connected in series using a short cable to add their respective voltages. If a positive electrical lead of one of the modules is placed next to a positive electrical lead of an adjacent module, or a negative electrical lead of one of the modules is placed next to a negative electrical lead of an adjacent module, these modules may be easily interconnected in parallel to add their respective currents.
  • positive and negative electrical leads of each module are located at the opposing sides of the multi-module power supply such that a positive electrical lead of one of the modules is preferably placed next to a negative electrical lead of a following module so that they can be easily connected using a short cable. It should be noted that when leads or terminals, are referred to, these leads actually come through a junction box that may be at the edge of the module structure, in the back of the module structure near the edge, or on the front of the module structure near the edge.
  • the below described invention provides a method to manufacture monolithically integrated multi-module power supplies with either the first or second configuration of electrical leads in relation with the distribution of the solar cells in each module.
  • the monolithically integrated multi-module power supplies shown in Figures 8-11 in top view include solar cells that the light receiving side of them is toward the paper plane.
  • the solar cells in each module are organized into at least one row including at least two solar cells.
  • solar cells denoted with letters, A, B, C, etc. indicate a row of a module.
  • the modules with the even number of rows e.g., rows A and B, or A, B, C and D, etc.
  • the modules with the odd number of rows e.g., row A, or rows A, B, and C, etc.
  • the modules with the odd number of rows e.g., row A, or rows A, B, and C, etc.
  • the modules with the odd number of rows e.g., row A, or rows A, B, and C, etc.
  • the second configuration of the electrical leads i.e., the electrical leads extending from both sides of the monolithically integrated multi-module power supply.
  • the monolithically integrated multi-module power supplies shown in Figures 8-11 may be manufactured using the principles of the roll lamination process described above.
  • FIG. 8 exemplifies a monolithically integrated multi-module power supply 600 having electrical leads with the first configuration.
  • the monolithically integrated multi- module power supply 600 with a first side 601A and a second side 601B includes a plurality of modules 602 having solar cells 603 organized in even numbered rows.
  • each module includes two rows, wherein the solar cells in the first row are denoted with A and the solar cells in the second row are denoted with B.
  • Each module 602 is surrounded by a moisture barrier seal frame 604 having edge seal portions 606 and divider seal portions 608, and a top elongated protective sheet (not shown) and a bottom elongated protective sheet 609.
  • each module 602 the solar cells 603 are surrounded by a support material 610 or encapsulant.
  • the solar cells 603 in each module are interconnected and a first electrical lead 614A or positive lead and a second electrical lead 614 B or negative lead have the first configuration so that they extend outside the modules 602 by passing through the edge seal portions 606 on the first side 601 A of the monolithically integrated multi- module power supply 600.
  • the electrical leads 614A and 614B are located at the same side, i.e., the first side 601A.
  • the first and the second electrical leads 614A and 614B in each module end up at the same side so that the polarity of the electrical leads alternates regularly along the side of the monolithically integrated multi-module power supply 600.
  • the first electrical lead 614A in one of the modules can be easily connected to the second electrical lead 614B in the following module on the same side as shown in the figure.
  • the positive electrical lead and the negative electrical lead will be located at the opposing sides of a monolithically integrated multi-module power supply.
  • FIG. 9 exemplifies a monolithically integrated multi-module power supply 700 having electrical leads with the second configuration due to the odd numbered row of solar cells.
  • the continuous multi-module power supply 700 with a first side 701A and a second side 70 IB includes a module 702 having solar cells 603 organized in a single row denoted with A.
  • Each module 702 is surrounded by a moisture barrier seal frame 704 having edge seal portions 706 and divider seal portions 708, and a top elongated protective sheet (not shown) and a bottom elongated protective sheet 709.
  • the solar cells 603 are surrounded by a support material 710.
  • the solar cells 603 in each module 702 are organized in a single row, i.e., row A, and a first electrical lead 714A or positive lead and a second electrical lead 714B or negative lead are located, in an alternating manner, at the first side 701A and the second side 701A.
  • the solar cells 603 in each module are interconnected and the first and the second electrical lead 714A and 714B with opposing polarity are extended outside the modules 703 by passing through the edge seal portions 706 on the first side 701A and the second side 701B of the continuous multi-module power supply 700.
  • a first electrical lead 714A in one of the modules 703 can be easily connected to a second electrical lead 714B in the following module as shown in the figure.
  • terminals Ti, T 2 , T 3 , and T 4 in the Figures 8-11 refer to the terminals of the monolithically integrated multi-module power supply.
  • FIG 10 exemplifies a monolithically integrated multi-module power supply 800 having electrical leads with the first configuration due to the even numbered row of solar cells.
  • the continuous multi-module power supply 800 with a first side 801A and a second side 80 IB includes a module 802 having solar cells 603 organized in a single row denoted with A.
  • Each module 802 is surrounded by a moisture barrier seal frame 804 having edge seal portions 806 and divider seal portions 808, and a top elongated protective sheet (not shown) and a bottom elongated protective sheet 809.
  • the solar cells 603 are surrounded by a support material 810.
  • the solar cells 603 in each module 802 are organized into four rows, i.e., row A, B, C and D, and a first electrical lead 814A or positive lead and a second electrical lead 814B or negative lead are located at the first side 80 IA.
  • the solar cells 603 in each module are interconnected and the first and the second electrical lead 814A and 814B with opposing polarity are extended outside the modules 803 by passing through the edge seal portion 806 on the first side 801 A of the monolithically integrated multi-module power supply 800. This way, a first electrical lead 814A in one of the modules 803 can be easily connected to a second electrical lead 818B in the following module.
  • connection devices 818A and/or 818B that can be connected to the additional electrical leads may be bypass diodes and/or cables that may be used to take some rows of solar cells, which may have degraded, out of the circuit of the overall monolithically integrated multi-module power supply. If the connection devices 818A, for example, are shorting cables, use of such shorting cables may enable the modules to still operate, if the row A and B of solar cells malfunction.
  • Figure 11 exemplifies a monolithically integrated multi-module power supply 900 having electrical leads with the second configuration due to the odd numbered row of solar cells.
  • the monolithically integrated multi-module power supply 900 with a first side 901A and a second side 901B includes a module 902 having solar cells 603 organized in five rows denoted with A, B, C, D and E.
  • Each module 902 is surrounded by a moisture barrier seal frame 904 having edge seal portions 906 and divider seal portions 908, and a top elongated protective sheet (not shown) and a bottom elongated protective sheet 909.
  • the solar cells 603 are surrounded by a support material 910.
  • Figures 8-11 show the flexibility of the designs of the present invention which may have many other configurations of solar cells.
  • manufacturing monolithically integrated multi-module power supplies comprising many individual modules each having its own moisture impermeable or moisture resistant structure has many advantages.
  • One advantage is better reliability in such multi- module devices. If any moisture enters into any of the individual modules of the monolithically integrated flexible multi-module power supply due to a failure of the top protective sheet, the bottom protective sheet or side sealant at that module location, the moisture would not be able to travel through to other modules because of the presence of divider sealants or divider walls. It should be noted that this concept of having individually sealed sections in a module structure is extendable to cases even a solar cell or a portion of a solar cell within a module may be individually sealed against moisture.
  • the protective shell of the module comprises top and bottom protective sheets, and an edge sealant to seal the edges at the perimeter of the protective sheets, and one or more divider sealants to divide the interior volume or space of the protective shell into sections, each section comprising at least a portion of a solar cell and an encapsulant encapsulating the front and back surfaces of the portion.
  • the edge and divider sealants are disposed between the top and the bottom protective sheets.
  • Figure 12A shows a top or front view of a module 950.
  • Figure 12B shows a cross sectional view along the line F1-F2.
  • the module 950 may not be the exact design of a module that one may manufacture. Rather, it is exemplary and demonstrative and is drawn for the purpose of demonstrating or showing various aspects of the present inventions in a general way in a single module structure.
  • the exemplary module 950 comprises twelve solar cells that are labeled as 95 IA,
  • the module 950 has a top protective sheet 962 and a bottom protective sheet 964 and an edge sealant 952 between the top protective sheet 962 and the bottom protective sheet 964.
  • the edge sealant 952 is placed at the edge of the module structure and is rectangular in shape in this example. For other module structures with different shapes, the edge sealant may also be shaped differently, following the circumference of the different shape modules.
  • the top protective sheet 962, the bottom protective sheet 964 and the edge sealant 952 forms a protective shell.
  • the module 950 further comprises divider sealants 953 that are formed within the protective shell, i.e. within the volume or space created by the top protective sheet 962, the bottom protective sheet 964 and the edge sealant 952.
  • the divider sealants 953 form a sealant pattern 954 that divides the protective shell into sealed sections 955. There are fifteen sections 955 in the exemplary module of Figure 3.
  • each section 955 in the middle region of the module 950 is bordered by only the divider sealants 953. Sections close to the edge of the module 950, on the other hand are bordered by divider sealants 953 as well as portions of the edge sealant 952.
  • each section may contain a solar cell, a portion of a solar cell, portions of more than one solar cell or more than one solar cell.
  • sections labeled as 955A and 955B each contain a different portion of the solar cell 95 IA, whereas the section labeled as 955C contains the single solar cell 95 IB.
  • the section labeled as 955D contains the solar cells 95 IH and 95 IL, as well as a portion of the solar cell 95 IK.
  • the sealant pattern 954 of the divider sealants 953 may be shaped in many different ways, such as rectangular, curved, circular, etc. Portions of the divider sealants 953 may be placed in the gap between the solar cells, on the solar cells and even under the solar cells. If the divider sealants 953 or their portions are placed on the solar cells, it is preferable that they are lined up with the busbars (not shown in the figure to simplify the drawing) of the solar cells so that any possible extra shadowing of the cells by the divider sealants 953 is avoided.
  • the portions of the divider sealants may be placed on divider sealant spaces 960 on the solar cells.
  • the divider sealant spaces 960 are designated locations on the front surface or the back surface of the solar cells.
  • the divider sealant spaces 960 do not contain any support material so that the divider sealant can be attached to the front or back side of the solar cell. It should be noted that busbars on solar cells already shadow the cell portions right under them and therefore, placing the divider sealants 953 over the busbars would not cause additional loss of area in the devices.
  • a portion 953A of the sealant pattern 954 is placed over the solar cell 95 IJ.
  • Another sealant portion 953B may also be present under the solar cell 95 IJ.
  • a bottom sealant pattern (not shown) may be employed under the solar cells.
  • the bottom sealant pattern may or may not match the shape of the sealant pattern 954.
  • the solar cells in the module 950 are encapsulated within an encapsulant 966 that surrounds and supports them.
  • an elongated top protective sheet may first be provided in a continuous or stepwise manner from a supply roll of a roll-to-roll module manufacturing system, and travels through a number of process stations, which add other components of the modules over the elongated protective sheet to form an embodiment of a continuous packaging structure or continuous multi-module device which may then be rolled onto a receiving spool to form a roll.
  • a continuous flexible module base comprising a transparent elongated sheet and moisture barrier layer sections deposited onto the transparent elongated sheet is used to manufacture a front side for at least two solar cell modules.
  • at least two moisture barrier layer sections are formed on a back surface of the transparent elongated sheet.
  • a separation region that does not have the moisture barrier layer, physically separates the moisture barrier layer sections from one another and fully surrounds them.
  • a moisture barrier frame surrounding each of the moisture barrier layer sections will be located on the separation region.
  • the continuous flexible module base may first be provided, in a continuous or stepwise manner, from a supply roll of a roll-to-roll module manufacturing system, and travels through a number of process stations, which add other components of the modules over the elongated protective sheet to form an embodiment of a continuous packaging structure or continuous multi-module device which may then be rolled onto a receiving spool to form a roll.
  • a process of manufacturing another embodiment of a continuous packaging structure 250 will be described using the exploded view of the continuous packaging or module structure 250 shown in Figures 13A and 13B. It should be noted that details of solar cell interconnection and wiring and terminals of the module structure are not shown to simplify the drawing.
  • the top elongated protective sheet 251 forms the front side or the light receiving side of the modules that will be manufactured using the processes of the invention and therefore it is transparent.
  • a moisture barrier layer 253 is deposited on the back surface
  • the moisture barrier layer 253 includes moisture barrier layer portions 253 A or sections, and it only covers module spaces 258.
  • the moisture barrier layer 253 is deposited and formed only on the predetermined locations referred to as module spaces 258 on the back surface 251A of the top elongated protective sheet 251.
  • Figure 13B shows the module spaces 258 as dotted line rectangles which are the footprints of the interiors of future modules that will be manufactured as described herein, on the back surface 25 IA of the top elongated protective sheet 251.
  • the continuous flexible module base 250A is provided at the first step of the roll-to roll process.
  • a moisture sealant 254 is applied on the back surface 25 IA of the top elongated protective sheet 251.
  • the moisture sealant 254 contacts a moisture sealant region 254A, also referred to as a separation region, on the back surface 25 IA making a good mechanical bond with the back surface 25 IA at that location.
  • Figure 13B shows the moisture sealant region 254A or the separation region surrounding the module spaces 258.
  • the moisture sealant 254 When deposited on the moisture sealant region 254A, the moisture sealant 254 surrounds the moisture barrier layer portions 253 A on the module spaces 258 and is preferably deposited along the two edges 252 of the protective sheet 251 and between the moisture barrier portions 253 A on the module spaces 258.
  • the portion of the moisture sealant 254 deposited along the edges 252 of the top elongated protective sheet 251 forms a side sealant 256 or side wall and the portion of the moisture sealant disposed between the module spaces 258 or ends of the module spaces forms a divider sealant 257 or divider wall.
  • the moisture sealant 254 may be in the form of a tape or a pre- shaped layer or it may be a viscous liquid that may be dispensed onto the moisture sealant region 254A of the back surface 25 IA of the top elongated protective sheet 251.
  • the side walls 256 and the divider walls 257 of the moisture sealant 254 form a plurality of cavities 259 on the top elongated protective sheet 251.
  • Each cavity 259 may be defined by one moisture barrier layer portion 253A and the side walls 256 and divider walls 257 that surround that moisture barrier layer portion 253A.
  • the moisture sealant 254 may be formed as a single piece continuous frame (moisture barrier frame) including the side walls and the divider walls that are shaped and dimensioned according to the desired solar module shape and size.
  • the moisture barrier frame When the moisture barrier frame is applied on the moisture sealant region 254A on the back surface 25 IA of the top elongated protective sheet 251, it forms the cavities 259 over the moisture barrier layer portions 253A. It should be noted that although substantially placed on the moisture sealant region 254A, some portion of the moisture sealant 254 may extend onto the moisture barrier layer portions 253A along their edges.
  • support material layers 260 or encapsulants and solar cells 262 or solar cell strings comprising two or more solar cells are placed over each moisture barrier layer portion 253 A within the cavities 259.
  • at least one solar cell 262 or solar cell string or circuit (in dotted lines) is shown interposed between the support material layers 260.
  • the solar cells 262 or the solar cell strings or the circuits are placed over the support material layer 260 in a face-down manner.
  • a light receiving side of each solar cell 260 or solar cell string or circuit faces toward the elongated top protective sheet 251.
  • Electrical leads (not shown) or terminals of the module may preferably be taken out of the cavity 259 through the side wall 256 of the moisture sealant 254 disposed along at least one of the long edges of the elongated protective sheet 251, in a way that the moisture sealant 254 also seals around the electrical leads.
  • solar cell strings or circuits include solar cells 263 that are electrically interconnected. However, the strings in each of the cavities 259 may or may not be electrically interconnected to one another.
  • the back elongated protective sheet 271 is placed on the moisture sealant 254 and over the support material 260 to complete the assembly of the components of a continuous packaging structure 250 before the lamination process.
  • the back elongated protective sheet 271 may or may not be transparent.
  • Figure 13C shows a cross- section view of the completed structure of the continuous packaging structure 250 after lamination, with modules 270, the cross section being taken along the middle of the illustrated continuous packaging structure 250.
  • the back elongated protective sheet 271 may have moisture barrier characteristics. There are such sheets in the market which have multi layer polymeric structures including a metallic layer, such as aluminum, as a moisture barrier.
  • FIGS. 12A and 12B described above show a general module structure employing various teachings of the present inventions, more simplified module structures will now be described below in connection to Figures 14A, 14B, 15, 16, 17, 18 and 19 to explain its unique features and benefits.
  • FIGS 14A and 14B show a solar cell module 101 including at least two solar cell units, a first solar cell unit 102 and a second solar cell unit 104.
  • the units 102 and 104 may be strings of solar cells.
  • the unit 102 may include solar cells 102A, 102B and 102C, and the unit 104 may include solar cells 104A, 104B and 104C.
  • Each solar cell includes a light receiving front portion 105A and a back portion 105B or base. The light receiving front portions of the solar cells form the front side of the solar cell units 102 and 104, while the back portions form the back side of the solar cell units.
  • the module 101 has a multisection structure with a first section 106 A and a second section 106B.
  • the first section 106 A includes the first string 102 and the second section 106B includes the second string 104.
  • the sections are formed between a top protective sheet 107 and a back protective sheet 108 of the module 101.
  • a first sealant 112 or an edge sealant seals the edges of the protective sheets at their perimeter thereby forming a protective shell 110.
  • a second sealant 114 or a divider sealant separates the strings 102 and 104 thereby forming the sections 106 A and 106B.
  • Both the edge sealant 112 and the divider sealant are disposed between and attached to the front and back protective sheets 107 and 108 as in the manner shown in Figures 14A and 14B.
  • the edge and the divider sealants may be two parts of a single piece sealant.
  • each solar cell string is encapsulated with a support material layer 116.
  • the support material 116 such as EVA may fully fill the sections 106A and 106B which are sealed by the edge sealant 112 and the divider sealant 114 and the first and second protective sheets 107 and 108. Separately sealed sections independently protect the solar cell strings encapsulated within them by the support material 116. This provides extra protection to the solar cell strings. For example, even if a defect in the edge sealant 112 near the first section 106 A allows moisture to leak into the first section 106A and causes malfunction of the first string 102, the second string 104 in the second section 106 B, which is sealed, can still function and produce power.
  • the solar cell module 101 of Figure 14A may, for example, have six sections instead of the two that is shown. In this case, each of the solar cells 102A, 102B, 102C, 104A, 104B and 104C may be in a section of its own.
  • a four section module design is shown in Figure 18.
  • the module 150 of Figure 18 comprises six cells, 15 IA, 15 IB, 151C, 15 ID, 15 IE, and 15 IF, all of which may be similar in design.
  • the solar cell design is shown in Figure 19.
  • the solar cell 15 IA comprises a busbar 160 and fingers 161. These design details of the solar cells are not shown in Figure 18 to simplify the drawing.
  • the module 150 has a four-section structure, each of the four sections 152A, 152B, 152C and 152D containing one half portion of three cells.
  • section 152 A contains a portion of cell 15 IA, a portion of cell 15 IB and a portion of cell 151C.
  • Sections 152A, 152B, 152C and 152D are formed by the edge sealant 155 and the divider sealants 156 which comprises three divider sealant portions 156A, 156B and 156C.
  • the divider sealant portions 156A and 156C are substantially aligned with the busbars 160 of the solar cells 15 IA, 15 IB, 151C, 15 ID, 15 IE, and 15 IF, so that shadowing losses due to the divider sealant portions 156A, 156B and 156C are minimized.
  • each section contains only a portion of a solar cell.
  • the edge sealant and divider sealants are materials that are highly resistive to moisture penetration.
  • the water vapor transmission rate of the edge and divider sealants is preferably below 0.001 gm/m 2 /day, more preferably below 0.0001 gm/m 2 /day.
  • a method of manufacturing an embodiment of the solar module 101 will be described in connection to Figure 15.
  • a pair of front support layers 116A is placed on an inner surface 107B of the front protective sheet 107 which is pre-cleaned. Sealant spaces 118 are left between the edge of the protective sheet 107 and between the front support layers 116A to accommodate the edge sealant and the divider sealant described above.
  • the front portion 105A of the solar cell strings 102 and 104 may be placed on the front support layers 116A.
  • the back support layers 116B are placed on the back sides 105B of the solar cell strings 102 and 104.
  • the edge sealant 112 and the divider sealant 114 are attached to the sealant spaces 118.
  • the front protective sheet 107 is typically a glass, but may also be a transparent flexible polymer film such as TEFZEL ® , or another polymeric film with moisture barrier coatings.
  • TEFZEL ® and TEFZEL ® are brand names of fluoropolymer materials from DuPont.
  • TEDLAR ® is polyvinyl fluoride (PVF)
  • TEFZEL ® is ethylene tetrafluoroethylene (ETFE) fluoropolymer.
  • the back protective sheet 108 may be a sheet of glass or a polymeric sheet such as TEDLAR ® , or another polymeric material which may or may not be transparent.
  • the back protective sheet 108 may comprise stacked sheets comprising various material combinations such as metallic films as moisture barrier.
  • the front and back support layer materials may preferably include EVA or thermoplastic polyurethane (TPU) material or both. It should be noted that the thicknesses of the components shown in the figures are not to scale.
  • the module 101 may have a rectangular or any other geometrical shape, and thus the size of the sections and the distribution of the solar cell strings may be arranged accordingly. It is also possible that either one or both of the front support layer and the back support layer may be eliminated from the module structures.
  • each solar cell includes a front portion and a back portion or base.
  • the base 105B includes a substrate and a contact layer formed on the substrate.
  • a preferred substrate material may be a metallic material such as stainless steel, aluminum or the like.
  • An exemplary contact layer material may be molybdenum.
  • the front portion 105 A may include an absorber layer, such as a CIGS absorber layer which is formed on the contact layer, and a transparent layer, such as a buffer- layer/ZnO stack, formed on the absorber layer.
  • An exemplary buffer layer may be a (Cd 5 Zn)S layer.
  • Conductive fingers (not shown) may be formed over the transparent layer.
  • Each interconnect electrically connects the substrate or the contact layer of one of the cells to the transparent layer of the next cell.
  • the solar cells may be interconnected using any other method known in the field.
  • Figure 16 shows another embodiment of the module 101 in side view. In this embodiment, the strings 102 and 104 are supported by the edge and divider sealants 112 and 114.
  • Gaps 122 are left between the back side of the strings and the back protective sheet 108 and between the front side of the strings and the front protective sheet 107.
  • the edges of the strings 102 and 104 are held in place and sealed by the edge and divider sealants 112 and 114 as in the manner shown in Figure 16. It is possible to fill any of the gaps 122 with a support layer (not shown) identified as support layer 116A or 116B in Figure 15.
  • Figure 17 shows yet another embodiment of the module 101 in side view. In this embodiment, a gap 122A is present over the front side of the strings 102 and 104.
  • the gap 122A may optionally be filled with a front support layer (not shown but similar to the front support layer 116A of Figure 15).
  • the back sides of the strings 102 and 104 are placed on the back sheet 108.
  • the edges of the strings 102 and 104 are held in place and sealed by the edge and the divider sealants 112 and 114 as in the manner shown in Figure 17.

Abstract

A continuous flexible sheet for use in fabricating flexible solar cell modules is provided. The continuous flexible sheet includes an elongated protective sheet having a front surface and a back surface. The back surface includes at least two barrier regions and an at least one separation region. At least two moisture barrier layers attached to the at least two barrier regions. The at least one separation region surrounds and physically separates the at least two barrier layers attached to the at least two barrier regions.

Description

FLEXIBLE THIN FILM PHOTOVOLTAIC MODULES AND MANUFACTURING THE
SAME
BACKGROUND
CLAIM OF PRIORITY
[0001] This application is a Continuation- in-Part of United States Patent Application Serial
No.12/250,507, filed on October 13, 2008, entitled "Structure and Method of Manufacturing Thin Film Photovoltaic Modules;" which is a Continuation-in-Part of United States Patent Application Serial No. 12/189,627, filed August 11, 2008, entitled "Photovoltaic Modules with Improved Reliability;" and this application relates to and claims priority from both of these applications; and this application also relates to and claims priority from United States Provisional Application No. 61/097,628, filed September 17, 2008, entitled "Method of Manufacturing Flexible Thin Film Photovoltaic Modules;" this application also relates to and claims priority from United States Provisional Application No. 61/117,083, filed November 21, 2008 entitled "Flexible Thin Film Photovoltaic Modules and Manufacturing the Same;" and this application also relates to and claims priority from United States Provisional Application No. 61/145,947, filed January 20, 2009, entitled "Flexible Thin Film Photovoltaic Modules and Manufacturing the Same," all of which are expressly incorporated herein by reference.
FIELD OF THE INVENTIONS
[0002] The aspects and advantages of the present inventions generally relate to apparatus and methods of photovoltaic or solar module design and fabrication and, more particularly, to roll-to-roll or continuous packaging techniques for flexible modules employing thin film solar cells.
DESCRIPTION OF THE RELATED ART
[0003] Solar cells are photovoltaic devices that convert sunlight directly into electrical power. The most common solar cell material is silicon, which is in the form of single or polycrystalline wafers. However, the cost of electricity generated using silicon-based solar cells is higher than the cost of electricity generated by the more traditional methods. Therefore, since early 1970's there has been an effort to reduce cost of solar cells for terrestrial use. One way of reducing the cost of solar cells is to develop low-cost thin film growth techniques that can deposit solar-cell- quality absorber materials on large area substrates and to fabricate these devices using high- throughput, low-cost methods.
[0004] Group IBIIIAVIA compound semiconductors comprising some of the Group IB (Cu,
Ag, Au), Group HIA (B, Al, Ga, In, Tl) and Group VIA (O, S, Se, Te, Po) materials or elements of the periodic table are excellent absorber materials for thin film solar cell structures. Especially, compounds of Cu, In, Ga, Se and S which are generally referred to as CIGS(S), or Cu(In,Ga)(S,Se)2 or CuIni-xGax (SySei-y)^ , where 0<x<l, 0<y<l and k is approximately 2, have already been employed in solar cell structures that yielded conversion efficiencies approaching 20%. Therefore, in summary, compounds containing: i) Cu from Group EB, ii) at least one of In, Ga, and Al from Group IIIA, and iii) at least one of S, Se, and Te from Group VIA, are of great interest for solar cell applications. It should be noted that although the chemical formula for CIGS(S) is often written as Cu(In,Ga)(S,Se)2, a more accurate formula for the compound is Cu(In,Ga)(S,Se)k, where k is typically close to 2 but may not be exactly 2. For simplicity, the value of k will be used as 2. It should be further noted that the notation "Cu(X,Y)" in the chemical formula means all chemical compositions of X and Y from (X=0% and Y=100%) to (X=100% and Y=0%). For example, Cu(In,Ga) means all compositions from CuIn to CuGa. Similarly, Cu(In,Ga)(S,Se)2 means the whole family of compounds with Ga/(Ga+In) molar ratio varying from 0 to 1, and Se/(Se+S) molar ratio varying from 0 to 1.
[0005] The structure of a conventional Group EB IIIA VIA compound photovoltaic cell such as a Cu(In,Ga,Al)(S,Se,Te)2 thin film solar cell is shown in Figure 1. A photovoltaic cell 10 is fabricated on a substrate 11, such as a sheet of glass, a sheet of metal, an insulating foil or web, or a conductive foil or web. An absorber film 12, which includes a material in the family of Cu(In,Ga,Al)(S,Se,Te)2, is grown over a conductive layer 13 or contact layer, which is previously deposited on the substrate 11 and which acts as the electrical contact to the device. The substrate 11 and the conductive layer 13 form a base 20 on which the absorber film 12 is formed. Various conductive layers comprising Mo, Ta, W, Ti, and their nitrides have been used in the solar cell structure of Figure 1. If the substrate itself is a properly selected conductive material, it is possible not to use the conductive layer 13, since the substrate 11 may then be used as the ohmic contact to the device. After the absorber film 12 is grown, a transparent layer 14 such as a CdS, ZnO, CdS/ZnO or CdS/ZnO/ITO stack is formed on the absorber film 12. Radiation 15 enters the device through the transparent layer 14. Metallic grids (not shown) may also be deposited over the transparent layer 14 to reduce the effective series resistance of the device. The preferred electrical type of the absorber film 12 is p-type, and the preferred electrical type of the transparent layer 14 is n-type. However, an n-type absorber and a p-type window layer can also be utilized. The preferred device structure of Figure 1 is called a "substrate-type" structure. A "superstrate-type" structure can also be constructed by depositing a transparent conductive layer on a transparent superstrate such as glass or transparent polymeric foil, and then depositing the Cu(In5Ga, Al)(S, Se5Te)2 absorber film, and finally forming an ohmic contact to the device by a conductive layer. In this superstrate structure light enters the device from the transparent superstrate side.
[0006] There are two different approaches for manufacturing PV modules. In one approach that is applicable to thin film CdTe, amorphous Si and CIGS technologies, the solar cells are deposited or formed on an insulating substrate such as glass that also serves as a back protective sheet or a front protective sheet, depending upon whether the device is "substrate-type" or "superstrate-type", respectively. In this case the solar cells are electrically interconnected as they are deposited on the substrate. In other words, the solar cells are monolithically integrated on the single- piece substrate as they are formed. These modules are monolithically integrated structures. For CdTe thin film technology the superstrate is glass which also is the front protective sheet for the monolithically integrated module. In CIGS technology the substrate is glass or polyimide and serves as the back protective sheet for the monolithically integrated module. In monolithically integrated module structures, after the formation of solar cells which are already integrated and electrically interconnected in series on the substrate or superstrate, an encapsulant is placed over the integrated module structure and a protective sheet is attached to the encapsulant. An edge seal may also be formed along the edge of the module to prevent water vapor or liquid transmission through the edge into the monolithically integrated module structure.
[0007] In standard Si module technologies, and for CIGS and amorphous Si cells that are fabricated on conductive substrates such as aluminum or stainless steel foils, the solar cells are not deposited or formed on the protective sheet. They are separately manufactured and then the manufactured solar cells are electrically interconnected by stringing them or shingling them to form solar cell strings. In the stringing or shingling process, the (+) terminal of one cell is typically electrically connected to the (-) terminal of the adjacent device. For the Group IBIIIAVIA compound solar cell shown in Figure 1, if the substrate 11 is conductive such as a metallic foil, then the substrate, which is the bottom contact of the cell, constitutes the (+) terminal of the device. The metallic grid (not shown) deposited on the transparent layer 14 is the top contact of the device and constitutes the (-) terminal of the cell. In shingling, individual cells are placed in a staggered manner so that a bottom surface of one cell, i.e. the (+) terminal, makes direct physical and electrical contact to a top surface, i.e. the (-) terminal, of an adjacent cell. Therefore, there is no gap between two shingled cells. Stringing is typically done by placing the cells side by side with a small gap between them and using conductive wires or ribbons that connect the (+) terminal of one cell to the (-) terminal of an adjacent cell. Solar cell strings obtained by stringing or shingling individual solar cells are interconnected to form circuits. Circuits may then be packaged in protective packages to form modules. Each module typically includes a plurality of strings of solar cells which are electrically connected to one another. The solar modules are constructed using various packaging materials to mechanically support and protect the solar cells in them against mechanical damage. The most common packaging technology involves lamination of circuits in transparent encapsulants. In a lamination process, in general, the electrically interconnected solar cells are covered with a transparent and flexible encapsulant layer which fills any hollow space among the cells and tightly seals them into a module structure, preferably covering both of their surfaces. A variety of materials are used as encapsulants, for packaging solar cell modules, such as ethylene vinyl acetate copolymer (EVA), thermoplastic polyurethanes (TPU), and silicones. However, in general, such encapsulant materials are moisture permeable; therefore, they must be further sealed from the environment by a protective shell, which forms resistance to moisture transmission into the module package. The nature of the protective shell determines the amount of water that can enter the package. The protective shell includes a front protective sheet and a back protective sheet and optionally an edge sealant that is at the periphery of the module structure (see for example, published application WO/2003/050891, "Sealed Thin Film PV Modules"). The top protective sheet is typically glass which is water impermeable. The back protective sheet may be a sheet of glass or a polymeric sheet such as TEDLAR® (a product of DuPont). The back protective polymeric sheet may or may not have a moisture barrier layer in its structure such as a metallic film like an aluminum film. Light enters the module through the front protective sheet. The edge sealant, which is presently used in thin film CdTe modules with glass/glass structure, is a moisture barrier material that may be in the form of a viscous fluid which may be dispensed from a nozzle to the peripheral edge of the module structure or it may be in the form of a tape which may be applied to the peripheral edge of the module structure. The edge sealant in Si-based modules is not between the top and bottom protective sheets but rather in the frame which is attached to the edge of the module. Moisture barrier characteristics of edge seals used for Si-based modules are not adequate for CIGS based modules as will be discussed later. [0008] Flexible module structures may be constructed using flexible CIGS or amorphous Si solar cells. Flexible modules are light weight, and unlike the standard glass based Si solar modules, are un-breakable. Therefore, packaging and transportation costs for flexible modules are much lower. However, packaging of flexible structures are more challenging. Glass handling equipment used in glass based PV module manufacturing are fully developed by many equipment suppliers. Handling of flexible sheets cannot be carried out using such standard equipment. The flexible sheets that constitute the various layers in the flexible module structure may be cut into sizes that are close to the desired area of the module, and then the standard module encapsulation procedures may be carried out by handling and moving these pieces around. A more manufacturing friendly approach for flexible module manufacturing is needed to increase the reliability of such modules and reduce their manufacturing cost. Some prior art processing approaches for flexible amorphous Si based device fabrication are described in US patents 4746618, 4773944, 5131954, 5968287, 5457057 and 5273608.
SUMMARY
[0009] The aspects and advantages of the present inventions generally relate to apparatus and methods of photovoltaic or solar module design and fabrication and, more particularly, to roll-to-roll or continuous packaging techniques for flexible modules employing thin film solar cells. [0010] In a particular embodiment is provided an apparatus comprising: a continuous flexible sheet for use in fabricating flexible solar cell modules, the continuous flexible sheet including: a front surface and a back surface, one of the front surface and the back surface including at least two moisture barrier regions and a separation region, wherein the separation region surrounds each moisture barrier region and physically separates adjacent moisture barrier regions; and a moisture barrier layer formed on each of the moisture barrier regions but not on the separation region.
[0011] In another embodiment there is described a monolithically integrated multi-module power supply, the monolithically integrated multi-module power supply including moisture barrier layers covering each of the ceilings of each of a plurality of sealed chambers that hold two solar cells that are electrically interconnected. [0012] In further embodiments described methods of manufacturing a photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] These and other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures, wherein: [0014] Figure 1 is a schematic view a thin film solar cell;
[0015] Figure 2A is a schematic cross sectional view of a flexible thin film solar module;
[0016] Figure 2B is a schematic top view of the module of Figure 2A;
[0017] Figures 3A-3F are schematic views of an embodiment of manufacturing of a continuous packaging structure of the present invention including a plurality of module structures; [0018] Figures 4A-4B are schematic views of transforming the continuous packaging structure into a continuous multi-module power device including a plurality of solar modules; [0019] Figure 5 is a schematic side view of a solar module of the present invention;
[0020] Figures 6A-6B are schematic views of an embodiment of manufacturing monolithically integrated multi-module power supplies; and
[0021] Figure 7 is a schematic view of a roll to roll system to manufacture flexible photovoltaic modules of the present invention.
[0022] Figure 8 exemplifies a monolithically integrated multi-module power supply 600 having electrical leads with the first configuration.
[0023] Figure 9 exemplifies a monolithically integrated multi-module power supply 700 having electrical leads with the second configuration due to the odd numbered row of solar cells. [0024] Figure 10 exemplifies a monolithically integrated multi-module power supply 800 having electrical leads with the first configuration due to the even numbered row of solar cells. [0025] Figure 11 exemplifies a monolithically integrated multi-module power supply 900 having electrical leads with the second configuration due to the odd numbered row of solar cells. [0026] Figure 12A is a schematic view of a solar cell module according to one embodiment;
[0027] Figure 12B is a schematic cross sectional view of the solar cell module shown in
Figure 12A taken along the line F1-F2;
[0028] Figures 13A-13B show a process of manufacturing another embodiment of a continuous packaging structure;
[0029] Figure 13C shows the completed structure of the continuous packaging structure of the embodiment made according to the process described in Figures 13A-13B; [0030] Figure 14A is a schematic view of an embodiment of a solar cell module;
[0031] Figure 14B is a schematic cross sectional view of the solar cell module shown in
Figure 14A taken along the line 14B-14B;
[0032] Figure 15 is a schematic view showing the components of the solar cell module during manufacturing;
[0033] Figures 16 and 17 are schematic views of various embodiments of the solar cell module;
[0034] Figure 18 is a module design; and
[0035] Figure 19 is a solar cell used in the module design of Figure 18.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0036] The preferred embodiments described herein provide methods of manufacturing flexible photovoltaic modules employing thin film Group IBIIIAVIA compound solar cells. The modules each include a moisture resistant protective shell within which flexible interconnected solar cells or cell strings are packaged and protected. The protective shell comprises a moisture barrier top protective sheet through which the light may enter the module, a moisture barrier bottom protective sheet, a support material or encapsulant covering at least one of a front side and a back side of each cell or cell string. The support material may preferably be used to fully encapsulate each solar cell and each string, top and bottom. The protective shell additionally comprises a moisture sealant that is placed between the top protective sheet and the bottom protective sheet along the circumference of the module and forms a barrier to moisture passage from outside into the protective shell from the edge area along the circumference of the module. Unlike in amorphous Si based flexible modules, the top protective sheet and the bottom protective sheet of the present module have a moisture transmission rate of less than 10~3 gm/m2/day, preferably less than 5XlO"4 gm/m2/day. Additionally, unlike in flexible amorphous Si modules, there is a moisture sealant along the circumference of the module with similar moisture barrier characteristics. [0037] In one embodiment, the present invention specifically provides a continuous manufacturing method to form a continuous packaging structure including a plurality of solar cell modules on elongated protective sheet bases. A moisture barrier frame is first applied on the elongated protective sheet having pre designated module areas. The moisture barrier frame is a moisture sealant (with transmission rate of < 10~3 gm/m2/day, or moisture breakthrough time of at least 20 years through the seal) which may be applied on the elongated protective sheet as a tape, gel or liquid. The walls of the moisture barrier frame surround the borders of each of the plurality of designated module areas and form a plurality of cavities defined by the walls of the moisture barrier frame and the designated module areas. The walls of the moisture barrier frame include side walls and divider walls. The side walls may form side walls of the plurality of cavities. Divider walls separate individual cavities from one another by forming adjoining walls between two cavities. Solar cell strings are placed into each of the cavities and supported by a support material filling each cavity. The strings in the adjacent cavities are not electrically connected to one another. A pair of power output wires or terminals is extended from the strings to the outside through the side walls. To complete the assembly, a second support material is placed over the strings and a second elongated protective sheet is placed over the support material and the moisture barrier frame to enclose the plurality of cavities, thereby forming the plurality of solar cell modules. After the continuous packaging structure is completed in a continuous manner, it is laminated to form a continuous multi-module device including a plurality of laminated solar cell modules. The continuous multi-module device can be cut into sections including a desired number of laminated solar cell modules that can be used in solar energy production applications. The laminated solar cell modules in each section can also be advantageously electrically connected by connecting power output wires that outwardly extend from each solar cell module. If any solar cell module malfunctions during the application, that malfunctioning portion may be easily removed and the remaining modules are reconnected for the system to continue performing. Such removal may be only electrical in nature, i.e. the failed module is electrically taken out of the circuit by simply disconnecting its power output wires. It is also possible to physically remove the failed module by cutting it out along the two divider walls on its two sides without negatively impacting the moisture sealant nature of the divider walls.
[0038] A manufacturing process of the modules may be performed by stacking various components of the modules on a continuous elongated protective sheet provided in a roll-to roll manner. Alternatively, the manufacturing process may be performed on a continuous flexible module base, comprising a transparent elongated sheet with moisture barrier layer sections deposited onto a back surface of the transparent elongated protective sheet. The moisture barrier layer sections are physically separated from one another by a separation region, also referred to as a moisture sealant region, which fully surrounds the moisture barrier layer sections and does not contain any moisture barrier layer. In this configuration, a moisture barrier frame is applied onto the separation region and the walls of the moisture barrier frame surround each of the moisture barrier layer sections and form a plurality of cavities defined by the walls of the moisture barrier frame and the moisture barrier layer sections.
[0039] Reference will now be made to the drawings wherein like numerals refer to like parts throughout. Figure 2A shows the cross section of an exemplary flexible module 1. Figure 2B is a top view of the same module. The exemplary flexible module 1 is an overly simplified one comprising only three cells 2a, 2b and 2c forming a string. In reality, many more cells and cell strings are used. The three cells 2a, 2b and 2c are interconnected using conductor wires 3 to form the cell string 2AA and terminal wires 4 extend to outside the perimeter formed by the top protective sheet 7 and the bottom protective sheet 8. It should be noted that in manufacturing, the wires 4 can be extended to outside the module by cutting the continuous packaging structure along line A-A as shown in Figure 2B, and then removing material 9a that exists within the area between lines Bl and B2, thereby leaving the wires 4 extending outside the perimeter of the module. Alternately wires 4 may be joined together within the package and then only a single wire (not shown) can extend outside the module. It is also possible to take the terminal wire from the back side of the module 1 as shown in the case of terminal wire 5. It is, however, preferable to bring the terminal wires through the moisture sealant 9 in a sealed manner. If a terminal is taken out through the top protective sheet 7 or the bottom protective sheet 8, moisture may enter the module structure through the hole or holes opened for the terminals to go through. Therefore such holes would have to be sealed against moisture permeation. The cell string 2AA is covered with a top support material or encapsulant 6a and a bottom encapsulant 6b. The top encapsulant 6a and the bottom encapsulant 6b are typically the same material but they may be two different materials that melt together and surround the cell string 2AA top and bottom. The top protective sheet 7 which is transparent and resistive to moisture permeation, the bottom protective sheet 8 which is resistive to moisture permeation, and a moisture sealant 9 along the edge of the module form a protective shell 100, which is filled with the cell string 2AA, the top encapsulant 6a and the bottom encapsulant 6b. It should be noted that the thicknesses of the components shown in the figures are not to scale.
[0040] The following part of the description includes an embodiment describing how a flexible module structure such as the one shown in Figures 2 A and 2B, as well as a modification of that flexible module structure as it relates to the terminal wires that extend outside a perimeter of the flexible module structure through the moisture sealant, may be fabricated in a continuous manner using continuous manufacturing techniques such as in-line or roll-to-roll process. [0041] As shown in Figures 3A-4B, during the roll-to roll or continuous process of the invention, an initial component such as an elongated top protective sheet 200A may be first provided in a continuous or stepwise manner from a supply roll of a roll-to-roll module manufacturing system, and travels through a number of process stations, which add other components of the modules over the elongated protective sheet to manufacture a continuous packaging structure including a plurality of solar cell modules. Resulting continuous multi-module device may then be rolled onto a receiving spool to form a roll, or the continuous multi-module device may be cut into smaller sections each containing one or more modules as will be explained later. [0042] Figure 3 A shows a first step of the process during which a section of the top elongated protective sheet 200A having a back surface 202 and two edges 203 is provided. The width of the elongated protective sheet may typically be in the range of 30-300 cm. The top elongated protective sheet forms the front side or the light receiving side of the modules that will be manufactured using the process of the invention. As shown in Figure 3B in top view and in Figure 3C in side view, in a second process step, a moisture sealant 204 is applied on the back surface 202 of the top elongated protective sheet 200A. The moisture sealant 204 surrounds module spaces 208 and is preferably deposited along the two edges 203 of the protective sheet 200A and between the module spaces 208. The portion of the moisture sealant 204 deposited along the edges 203 A of the top elongated protective sheet 200A will be called side sealant 206 or side wall and the portion of the moisture sealant disposed between the module spaces 208 or ends of the module spaces will be called divider sealant 207 or divider wall. The moisture sealant 204 may be in the form of a tape or it may be a viscous liquid that may be dispensed onto the back surface 202 of the top elongated protective sheet 200A. The module spaces 208 are the spaces on the back surface 202 that are bordered or surrounded by the moisture sealant 204 applied on the back surface 202. As shown in Figure 3C, the side walls 206 and the divider walls 207 of the moisture sealant 204 form a plurality of cavities 209 on the top elongated protective sheet 200A. Each cavity 209 may be defined by one module space 208 and the side walls 206 and divider walls 207 that surround that module space 208. In this respect, the moisture sealant 204 may be formed as a single piece continuous frame including the side walls and the divider walls which are shaped and dimensioned according to the desired solar cell module shape and size. When such frame is applied on the back surface 202 of the top elongated protective sheet 200A, it forms the cavities 209.
[0043] As shown in Figure 3D in top view and in Figure 3E in side schematic view, after disposing the moisture sealant 204, support material layers 210 or encapsulants are placed over each module space 208 within the cavities 209 and then the solar cell strings 212 are placed over the support material 210 in a face-down manner. A light receiving side 215A of each solar cell 213 in each string 212 faces toward the elongated top protective sheet 200A. Electrical leads 214 or terminals of the module may preferably be taken out of the cavity 209 through the side wall 206 of the moisture sealant 204 disposed along at least one of the long edges of the elongated protective sheet 200A, in a way that the moisture sealant 204 also seals around the electrical leads 214. As shown in the figures, solar cell strings 212 include solar cells 213 that are electrically interconnected. However, the strings 212 in each of the cavities 209 are not electrically interconnected to one another, i.e. there is no electrical connection between cells in one cavity with the cells in an adjacent cavity. It is, however, possible to have such interconnections as described in the US patent application with serial number 12/189627 entitled "photovoltaic modules with improved reliability" filed August 11, 2008, in which a fabricated module may comprise two or more sealed compartments (e.g. the cavities 209) each containing solar cell strings.
[0044] As shown in Figure 3F in side schematic view, in the following step, back side 215B or base of the solar cells 213 are covered with another layer of support material 210. A back elongated protective sheet 200B is placed on the moisture sealant 204 and over the support material 210 to complete the assembly of the components of a continuous packaging structure 300 having a plurality of solar cell module structures 302.
[0045] As shown in Figure 4A, the continuous packaging structure 300 is processed in a laminator, such as a roll laminator with rollers 450 to transform it to a continuous multi-module device 300A having a plurality of solar cell modules 302A. During the lamination process, the support material 210 in each module structure 302 melts and adheres to the solar cell strings 212 and to the top and back elongated protective sheets 200A and 200B. The moisture sealant 204 also melts and adheres to the top and back elongated protective sheets 200A and 200B. [0046] Figure 4B shows in top view the continuous multi-module device 300A having the solar cell modules 302A after the continuous packaging structure 300 is processed in the laminator. It should be noted that in this continuous process, support materials that do not involve chemical cross linking are preferred to support materials that involve cross linking, such as EVA. The preferred support materials include silicones and thermo plastic materials that may have melting temperatures in the range of 90-150 C. The moisture sealant 204 may also be a thermo plastic that can be melted easily in a roll laminator where pressure and heat may be applied to the module structure in presence or in absence of vacuum. It should be noted that the sealant material 204 may be dispensed in liquid form or it may be in the form of an adhesive tape that adheres on the back surface 202 of the top elongated protective sheet 200A. If liquid silicone is used as the support material 210, the silicone may be dispensed onto each module area defined by the cavity 209 formed by the back surface 202 and the sealant material 204. Therefore, the back surface 202 and the sealant material 204 acts like a container to contain the liquid silicone support material 210. The silicone support material 210 may be partially cured before the cell string is placed onto it (see Figures 3D and 3E) so that the cell string does not sink into the liquid and touch the back surface 202 of the top elongated protective sheet 200A. For cell strings containing flexible CIGS solar cells fabricated on stainless steel substrates, it may be difficult to keep all the cells in the string lying flat on the top surface of the semi-cured silicone layer. Therefore, a series of magnets may be used under the top elongated protective sheet 200A. These magnets pull the cell string towards the top elongated protective sheet 200A and keep them flat against the semi-cured front support material for CIGS solar cells fabricated on magnetic stainless steel foils such as Grade 430 stainless steel. With the magnets in place, the back support silicon material may be dispensed over the cell strings to cover the back side of the cells. With the magnets still in place, the silicone may be heated to be partially or fully cured. This way the cells may be trapped in between two layers of partially or fully cured silicone layers. Then the magnets may be removed, the back elongated protective sheet 200B may be placed on the moisture sealant 204 and the support material 210 to complete the formation of a continuous packaging structure 300 including a plurality of module structures. Partial curing of silicone may be achieved at a temperature range of 60-1000C.
[0047] Referring back to Figure 4A, in order to eliminate air entrapment within the modules, the divider sealants 207 between the module structures 302 may have small cuts or holes so that as the continuous packaging structure 300 is laminated any air within a particular module structure 302, as it is transformed into a module between the rollers 450, passes into the next module structure through the uncured divider sealant between the two module structures. Since the next module is not laminated yet and thereby not sealed, entrapped air is released from this module structure and the divider sealant 207 with cuts or holes melts and heals these cuts and holes. Alternatively, to avoid air entrapment, the roll lamination may be carried out in a vacuum environment with pressure values in the order of milli-Torrs. Such vacuum levels can be obtained by building separately pumped chambers through which the continuous packaging structure 300 passes through to arrive to the chamber where the roll lamination process is carried out. For example, the continuous packaging structure may enter a first chamber through a narrow slit and then go in and out a number of chambers through narrow slits before arriving into the roll lamination chamber and then travel through several other chambers before exiting the system through a last chamber. This way the pressure may be changed from near atmospheric pressure (760 Torr) in the first and last chambers to a much lower value (such as 100 mTorr) in the lamination chamber.
[0048] Figure 4B shows the continuous multi-module device 300A after the roll lamination process in top view wherein the light receiving side of the solar cells 213 is toward the paper plane. The continuous multi-module device 300A may be rolled into a receiving roll (not shown) with the electrical leads 214 or terminals of each module in the multi-module device protruding from the side of the receiving roll. This way the terminals do not interfere with the rolling process. The roll may be shipped for further processing or installation in the field. Figure 4B shows the continuous multi- module device 300A obtained after the lamination and sealing process. Each of the modules 302A in this multi-module device is sealed against moisture transmission from outside environment into the module structure where the solar cell strings 212 are encapsulated.
[0049] The continuous process described above is very versatile. Once the continuous multi- module device is formed, this device may be used in a variety of ways. In one approach the continuous multi-module packaging device is cut into individual modules 302A along the dotted cut lines 'A' which are within the divider walls as shown in Figure 4B, producing completely separate and sealed individual modules. The electrical leads 214 of each module 302A are on the side and does not get affected or cut by this process and the integrity of the moisture sealant 204 is not compromised anywhere along the perimeter of each module. Having electrical leads 214 come out the side along at least one of the two long edges 203 of the continuous multi-module device 302A also maximizes the active area of each module while keeping the integrity of the moisture sealant 204.
[0050] In another approach, the continuous multi-module device may be used to form monolithically integrated multi-module power supplies comprising two or more electrically interconnected modules on a common, uncut substrate or superstrate as will be described more fully below. Figure 5 shows in side view an individual module 302A that is manufactured using the process of the present invention by cutting and separating each of the modules 302A from the continuous multi-module device 300A as shown in Figure 4B. The solar cell string 212 is coated with the support material 210 and disposed between a top protective sheet 303 A and a bottom protective sheet 3O3B. The top protective sheet 3O3A and the bottom protective sheet 3O3B are portions of the top and bottom elongated protective sheets 200A and 200B. The moisture sealant 204 extends between the protective sheets 303 A and 300B and seals the perimeter of the module. As mentioned each solar cell 213 includes the front portion 215A or light receiving portion and the back portion 215B or base. As will be appreciated, in operation, sun light enters the module through the top protective sheet 303 A and arrives at the front portion 215A of the solar cells through the support material 210. The base 215B includes a substrate and a contact layer formed on the substrate. A preferred substrate material may be a metallic material such as stainless steel, aluminum or the like. An exemplary contact layer material may be molybdenum. The front portion 215A of the solar cells may include an absorber layer 305, such as a CIGS absorber layer which is formed on the contact layer, and a transparent layer 306, such as a buffer-layer/ZnO stack, formed on the absorber layer. An exemplary buffer layer may be a (Cd,Zn)S layer. Conductive fingers 308 may be formed over the transparent layer. Conductive leads 310 electrically connect the substrate or the contact layer of one of the solar cells to the transparent layer of the next solar cell. However, the solar cells may be interconnected using any other method known in the field such as shingling. [0051] The front protective sheet 200A may be a transparent flexible polymer film such as
TEFZEL®, or another polymeric film. The front protective sheet 200A comprises a transparent moisture barrier coating which may comprise transparent inorganic materials such as alumina, alumina silicates, silicates, nitrides etc. Examples of such coatings may be found in the literature (see for example, L. Olsen et al., "Barrier coatings for CIGSS and CdTe cells", Proc. 31st IEEE PV Specialists Conf., p.327, 2005). TEDLAR® and TEFZEL® are brand names of fluoropolymer materials from DuPont. TEDLAR® is polyvinyl fluoride (PVF), and TEFZEL® is ethylene tetrafluoroethylene (ETFE) fluoropolymer. The back protective sheet 200B may be a polymeric sheet such as TEDLAR®, or another polymeric material which may or may not be transparent. The back protective sheet may comprise stacked sheets comprising various material combinations such as metallic films (like Aluminum) as moisture barrier.
[0052] As stated before, one advantage of the present invention is its versatility. Instead of cutting and separating each of the modules 302A from the continuous multi-module device 300A shown in Figure 4B, the cutting operation may be performed to form monolithically integrated multi-module power supplies with power ratings much in excess of what is the norm today. Typical high wattage modules in the market have power ratings in the range of 2OO-3OOW. These are structures fabricated using standard methods by interconnecting all solar cells and strings within the module structure. With the light weight and flexible structures of the present invention it is feasible to construct monolithically integrated multi-module power supplies with ratings of 600W and over and even with power ratings of over 1000 W. A roll of a flexible and light weight power generator with multi kW rating on a single substrate can enable new applications in large scale solar power fields. It should be noted that, using the teachings of the present inventions it is possible to build a single module of multi kW rating (such as 2000-5000 W), the single module having one moisture sealant in the form of a moisture barrier frame around its perimeter (see, for example, Figure 2A). However, manufacturing monolithically integrated multi-module power supplies comprising many individual modules each having its own moisture impermeable or moisture resistant structure has many advantages. One advantage is better reliability in such multi-module devices. If any moisture enters into any of the individual modules of the monolithically integrated flexible multi-module power supply due to a failure of the top protective sheet, the bottom protective sheet or side sealant at that module location, the moisture would not be able to travel through to other modules because of the presence of divider sealants or divider walls. Therefore, the rest of the monolithically integrated multi-module power supply would continue producing power. Such reliability improvements are discussed in detail in United States Patent Application Serial No. 12/189,627, filed August 11, 2008 titled "Photovoltaic modules with improved reliability." Another advantage is the application flexibility offered by the method of manufacturing described above. As discussed before, the continuous multi-module device 300A shown in Figure 4B may be cut into single module structures for applications that require low wattage (100-600 W). For large rooftop applications, the continuous multi-module device may be cut to include 5-10 modules and therefore provide a monolithically integrated multi-module power supply with a rating in the range of, for example, 500-2000 W. For very large power field applications, monolithically integrated multi- module power supplies with power ratings of 1000-20000 W or higher may be employed. The important point is that all of these products can be manufactured from the same manufacturing line by just changing the steps of cutting. Presence of divider sealants between unit modules makes this possible. If divider sealants were not present, long and continuous module structures could not be cut into smaller units and be employed since moisture entering through the cut edges would limit the life of the cut modules or multi-module structures to much less than 20 years. For example, CIGS modules without a proper edge sealant would have a life of only a few years before loosing almost 50% of their power rating. [0053] Certain advantages of the present invention may be demonstrated by an exemplary continuous multi-module device 500 shown in Figure 6A, which may be manufactured using the process of the present invention described above. The continuous multi-module device 500, including solar cell modules 502A-502J, shown in Figure 6A may be a portion of a longer continuous structure. Each module includes a solar cell string 512 having interconnected solar cells
513 and the light receiving side of the solar cells 213 facing toward the paper plane. Electrical leads
514 or output wires from each module are positioned along the side of the continuous multi-module device 500 as in the manner shown in Figure 6A. The modules are separated from one another by divider walls 503 of the moisture sealant.
[0054] As shown in Figure 6B, when an exemplary section 504 including the modules 502A-
502E is separated from the continuous multi-module device 500 as described above, output wires 514 are interconnected to provide a combined power output from the modules 502A-502E of the section 504. For example if the power rating of each module is IOOW and if the cut section contains 10 modules that are interconnected, the resulting monolithically integrated multi-module power supply is a continuous, single piece 1000 W supply. If the cut section contains 20 modules a 2000W power supply would be obtained. As shown in Figure 6B, the interconnection between modules of the monolithically integrated multi-module power supply may be a series interconnection where the (+) terminal of each module is connected to a (-) terminal of an adjacent module. It should be noted that individual modules in the monolithically integrated multi-module power supply may also be interconnected in parallel mode.
[0055] The monolithically integrated multi-module power supply design of Figure 6B provides advantage for deployment in the field. One advantage is the simplicity of installing a flexible, single piece, high-power power supply in the field. Elimination of handling many individual modules, elimination of many individual installation structures are some of the advantages. Another advantage is the ease of eliminating a malfunctioning module in the monolithically integrated multi-module power supply. This is possible because the inter-module interconnection terminals are outside and accessible. In section 504, for example, if the module 502 malfunctions, instead of discarding the whole section 504, the module 502B would be taken out of the circuitry by disconnecting its wires and the remaining modules 502A, 502C, 502D and 502E would be left interconnected and thus continue providing full power. Bypass diodes and other balance of system components may also be connected to the monolithically integrated multi-module power supply terminals. Although the cell strings in each module are shown to be parallel to the long edge of the monolithically integrated multi-module power supply shown in Figures 6A and 6B, cell strings may actually be placed in different directions in the module structure. For example, by placing cell strings perpendicular to the long edge of the monolithically integrated multi-module power supply one can reduce the length of each module (defined by the distance between the divider sealants or walls) compared to its width. This way the length of the wires used to interconnect the adjacent modules would be minimized to save cost and power loss in the interconnection wires and other hardware.
[0056] Figure 7 shows a roll to roll system 400 to manufacture the continuous multi-module device 300A shown in Figures 3A-4B. The system 400 includes a process station 402 including a number of process units 404A-404F to perform above described process steps as the top protection layer 200A is supplied from the supply roll 405A and advanced through the process station 402. After processed in the lamination unit, the continuous packaging structure 300 is picked up and wrapped around the receiving roll 405B. In the following step the receiving roll 405B is taken into a cutting station to cut the continuous packaging structure 300A. In an alternative system without the receiving roll, the laminated continuous packaging structure 300 may be directly advanced into a cutting station and cut into individual modules or into monolithically integrated multi-module power supplies.
[0057] In the following, one particular configuration of a continuous multi module device with the electrical leads or terminals of each module extending from one side of the continuous multi-module device will be referred to as a first configuration. As will be described more fully below, a second particular configuration will refer to the electrical leads extending from both sides of a continuous multi-module device or a monolithically integrated multi-module power supply. [0058] As will be more fully described below, the number and the relative distribution of the solar cells in each module may help to pre-determine whether the monolithically integrated multi- module power supply to be manufactured may have the first configuration or the second configuration. In the first configuration, positive and negative electrical leads of each module are located at the same side of the monolithically integrated multi-module power supply such that a positive electrical lead of one of the modules is preferably placed next to a negative electrical lead of an adjacent module so that they can be connected in series using a short cable to add their respective voltages. If a positive electrical lead of one of the modules is placed next to a positive electrical lead of an adjacent module, or a negative electrical lead of one of the modules is placed next to a negative electrical lead of an adjacent module, these modules may be easily interconnected in parallel to add their respective currents. In the second configuration, positive and negative electrical leads of each module are located at the opposing sides of the multi-module power supply such that a positive electrical lead of one of the modules is preferably placed next to a negative electrical lead of a following module so that they can be easily connected using a short cable. It should be noted that when leads or terminals, are referred to, these leads actually come through a junction box that may be at the edge of the module structure, in the back of the module structure near the edge, or on the front of the module structure near the edge.
[0059] The below described invention provides a method to manufacture monolithically integrated multi-module power supplies with either the first or second configuration of electrical leads in relation with the distribution of the solar cells in each module. Accordingly, the monolithically integrated multi-module power supplies shown in Figures 8-11 in top view include solar cells that the light receiving side of them is toward the paper plane. The solar cells in each module are organized into at least one row including at least two solar cells. In the below description, solar cells denoted with letters, A, B, C, etc., indicate a row of a module. Further, the modules with the even number of rows, e.g., rows A and B, or A, B, C and D, etc., have the first configuration of the electrical leads, i.e., the electrical leads extending from one side, and the modules with the odd number of rows, e.g., row A, or rows A, B, and C, etc., have the second configuration of the electrical leads, i.e., the electrical leads extending from both sides of the monolithically integrated multi-module power supply. The monolithically integrated multi-module power supplies shown in Figures 8-11 may be manufactured using the principles of the roll lamination process described above.
[0060] Figure 8 exemplifies a monolithically integrated multi-module power supply 600 having electrical leads with the first configuration. In Figure 8, the monolithically integrated multi- module power supply 600 with a first side 601A and a second side 601B includes a plurality of modules 602 having solar cells 603 organized in even numbered rows. In this example, each module includes two rows, wherein the solar cells in the first row are denoted with A and the solar cells in the second row are denoted with B. Each module 602 is surrounded by a moisture barrier seal frame 604 having edge seal portions 606 and divider seal portions 608, and a top elongated protective sheet (not shown) and a bottom elongated protective sheet 609. In each module 602, the solar cells 603 are surrounded by a support material 610 or encapsulant. The solar cells 603 in each module are interconnected and a first electrical lead 614A or positive lead and a second electrical lead 614 B or negative lead have the first configuration so that they extend outside the modules 602 by passing through the edge seal portions 606 on the first side 601 A of the monolithically integrated multi- module power supply 600. As mentioned above, since the solar cells 603 in each module 602 are organized in two rows, i.e., rows A and B, the electrical leads 614A and 614B are located at the same side, i.e., the first side 601A. As shown in Figure 8, when the number of rows are even numbered, due to the way the solar cells in even numbered rows are electrically connected, the first and the second electrical leads 614A and 614B in each module end up at the same side so that the polarity of the electrical leads alternates regularly along the side of the monolithically integrated multi-module power supply 600. This way, the first electrical lead 614A in one of the modules can be easily connected to the second electrical lead 614B in the following module on the same side as shown in the figure. However, if the number of rows in each module was an odd number, the positive electrical lead and the negative electrical lead will be located at the opposing sides of a monolithically integrated multi-module power supply.
[0061] Figure 9 exemplifies a monolithically integrated multi-module power supply 700 having electrical leads with the second configuration due to the odd numbered row of solar cells. In Figure 9, the continuous multi-module power supply 700 with a first side 701A and a second side 70 IB includes a module 702 having solar cells 603 organized in a single row denoted with A. Each module 702 is surrounded by a moisture barrier seal frame 704 having edge seal portions 706 and divider seal portions 708, and a top elongated protective sheet (not shown) and a bottom elongated protective sheet 709. In each module 702, the solar cells 603 are surrounded by a support material 710. The solar cells 603 in each module 702 are organized in a single row, i.e., row A, and a first electrical lead 714A or positive lead and a second electrical lead 714B or negative lead are located, in an alternating manner, at the first side 701A and the second side 701A. The solar cells 603 in each module are interconnected and the first and the second electrical lead 714A and 714B with opposing polarity are extended outside the modules 703 by passing through the edge seal portions 706 on the first side 701A and the second side 701B of the continuous multi-module power supply 700. This way, a first electrical lead 714A in one of the modules 703 can be easily connected to a second electrical lead 714B in the following module as shown in the figure. It should be noted that terminals Ti, T2, T3, and T4 in the Figures 8-11 refer to the terminals of the monolithically integrated multi-module power supply.
[0062] Figure 10 exemplifies a monolithically integrated multi-module power supply 800 having electrical leads with the first configuration due to the even numbered row of solar cells. In Figure 10, the continuous multi-module power supply 800 with a first side 801A and a second side 80 IB includes a module 802 having solar cells 603 organized in a single row denoted with A. Each module 802 is surrounded by a moisture barrier seal frame 804 having edge seal portions 806 and divider seal portions 808, and a top elongated protective sheet (not shown) and a bottom elongated protective sheet 809. In each module 802, the solar cells 603 are surrounded by a support material 810. The solar cells 603 in each module 802 are organized into four rows, i.e., row A, B, C and D, and a first electrical lead 814A or positive lead and a second electrical lead 814B or negative lead are located at the first side 80 IA. The solar cells 603 in each module are interconnected and the first and the second electrical lead 814A and 814B with opposing polarity are extended outside the modules 803 by passing through the edge seal portion 806 on the first side 801 A of the monolithically integrated multi-module power supply 800. This way, a first electrical lead 814A in one of the modules 803 can be easily connected to a second electrical lead 818B in the following module. In this embodiment, there may be additional electrical leads coming from the modules to accommodate other devices such as bypass diodes. These additional electrical leads are shown schematically in Figure 10 as 81A and 816B. The connection devices 818A and/or 818B that can be connected to the additional electrical leads may be bypass diodes and/or cables that may be used to take some rows of solar cells, which may have degraded, out of the circuit of the overall monolithically integrated multi-module power supply. If the connection devices 818A, for example, are shorting cables, use of such shorting cables may enable the modules to still operate, if the row A and B of solar cells malfunction. Since the row A and B of solar cells are shorted out by a cable in this example, the rest of the cells in rows C and D will continue to function properly. Figure 11 exemplifies a monolithically integrated multi-module power supply 900 having electrical leads with the second configuration due to the odd numbered row of solar cells. In Figure 11, the monolithically integrated multi-module power supply 900 with a first side 901A and a second side 901B includes a module 902 having solar cells 603 organized in five rows denoted with A, B, C, D and E. Each module 902 is surrounded by a moisture barrier seal frame 904 having edge seal portions 906 and divider seal portions 908, and a top elongated protective sheet (not shown) and a bottom elongated protective sheet 909. In each module 902, the solar cells 603 are surrounded by a support material 910. Figures 8-11 show the flexibility of the designs of the present invention which may have many other configurations of solar cells.
[0063] As stated above, manufacturing monolithically integrated multi-module power supplies comprising many individual modules each having its own moisture impermeable or moisture resistant structure has many advantages. One advantage is better reliability in such multi- module devices. If any moisture enters into any of the individual modules of the monolithically integrated flexible multi-module power supply due to a failure of the top protective sheet, the bottom protective sheet or side sealant at that module location, the moisture would not be able to travel through to other modules because of the presence of divider sealants or divider walls. It should be noted that this concept of having individually sealed sections in a module structure is extendable to cases even a solar cell or a portion of a solar cell within a module may be individually sealed against moisture. Accordingly, in another embodiment, the protective shell of the module comprises top and bottom protective sheets, and an edge sealant to seal the edges at the perimeter of the protective sheets, and one or more divider sealants to divide the interior volume or space of the protective shell into sections, each section comprising at least a portion of a solar cell and an encapsulant encapsulating the front and back surfaces of the portion. The edge and divider sealants are disposed between the top and the bottom protective sheets. In this sectioned module configuration, any local defect through the protective shell will affect the solar cell(s) or solar cell portions within a particular section that may be in contact with this defect and will not affect the solar cell(s) or solar cell portions that are in other sections which are separated from the particular section by the divider sealants. Therefore, the solar cells or solar cell portions in the sections that are not affected by the defect will continue functioning and producing power.
[0064] Figure 12A shows a top or front view of a module 950. Figure 12B shows a cross sectional view along the line F1-F2. It should be noted that the module 950 may not be the exact design of a module that one may manufacture. Rather, it is exemplary and demonstrative and is drawn for the purpose of demonstrating or showing various aspects of the present inventions in a general way in a single module structure.
[0065] The exemplary module 950 comprises twelve solar cells that are labeled as 95 IA,
951B, 951C, 951D, 951E, 951F, 951G, 951H, 9511, 951J, 951K, and 951L. These solar cells are electrically interconnected. The interconnections are not shown in the figure to simplify the drawing. In Figure 3 there are gaps between the solar cells. However, as explained before, it is possible that these solar cells may be shingled and therefore, there may not be gaps between them. Cells may also be shaped differently. For example, they may be elongated with one dimension being 2-100 times larger than the other dimension. The module 950 has a top protective sheet 962 and a bottom protective sheet 964 and an edge sealant 952 between the top protective sheet 962 and the bottom protective sheet 964. The edge sealant 952 is placed at the edge of the module structure and is rectangular in shape in this example. For other module structures with different shapes, the edge sealant may also be shaped differently, following the circumference of the different shape modules. The top protective sheet 962, the bottom protective sheet 964 and the edge sealant 952 forms a protective shell. [0066] The module 950 further comprises divider sealants 953 that are formed within the protective shell, i.e. within the volume or space created by the top protective sheet 962, the bottom protective sheet 964 and the edge sealant 952. The divider sealants 953 form a sealant pattern 954 that divides the protective shell into sealed sections 955. There are fifteen sections 955 in the exemplary module of Figure 3. Some of the sections 955 in the middle region of the module 950 are bordered by only the divider sealants 953. Sections close to the edge of the module 950, on the other hand are bordered by divider sealants 953 as well as portions of the edge sealant 952. As can be seen from Figure 3, each section may contain a solar cell, a portion of a solar cell, portions of more than one solar cell or more than one solar cell. For example, sections labeled as 955A and 955B each contain a different portion of the solar cell 95 IA, whereas the section labeled as 955C contains the single solar cell 95 IB. The section labeled as 955D, on the other hand, contains the solar cells 95 IH and 95 IL, as well as a portion of the solar cell 95 IK. The sealant pattern 954 of the divider sealants 953 may be shaped in many different ways, such as rectangular, curved, circular, etc. Portions of the divider sealants 953 may be placed in the gap between the solar cells, on the solar cells and even under the solar cells. If the divider sealants 953 or their portions are placed on the solar cells, it is preferable that they are lined up with the busbars (not shown in the figure to simplify the drawing) of the solar cells so that any possible extra shadowing of the cells by the divider sealants 953 is avoided.
[0067] As shown in Figure 12A and 12B, the portions of the divider sealants may be placed on divider sealant spaces 960 on the solar cells. The divider sealant spaces 960 are designated locations on the front surface or the back surface of the solar cells. The divider sealant spaces 960 do not contain any support material so that the divider sealant can be attached to the front or back side of the solar cell. It should be noted that busbars on solar cells already shadow the cell portions right under them and therefore, placing the divider sealants 953 over the busbars would not cause additional loss of area in the devices. As can be seen in the cross sectional view of the module 950 in Figure 12B a portion 953A of the sealant pattern 954 is placed over the solar cell 95 IJ. Another sealant portion 953B may also be present under the solar cell 95 IJ. In other words, a bottom sealant pattern (not shown) may be employed under the solar cells. The bottom sealant pattern may or may not match the shape of the sealant pattern 954. The solar cells in the module 950 are encapsulated within an encapsulant 966 that surrounds and supports them. After this general description of a general module structure employing various teachings of the present inventions, more simplified module structures will now be described to explain its unique features and benefits. [0068] As described above in connection to Figures 3A-3F, during the roll-to roll or continuous or stepwise manufacturing of the power supplies or module structures an elongated top protective sheet may first be provided in a continuous or stepwise manner from a supply roll of a roll-to-roll module manufacturing system, and travels through a number of process stations, which add other components of the modules over the elongated protective sheet to form an embodiment of a continuous packaging structure or continuous multi-module device which may then be rolled onto a receiving spool to form a roll. As will be described more fully below, in another embodiment, a continuous flexible module base comprising a transparent elongated sheet and moisture barrier layer sections deposited onto the transparent elongated sheet is used to manufacture a front side for at least two solar cell modules. To form the continuous flexible module base, at least two moisture barrier layer sections are formed on a back surface of the transparent elongated sheet. A separation region that does not have the moisture barrier layer, physically separates the moisture barrier layer sections from one another and fully surrounds them. Further in the process, a moisture barrier frame surrounding each of the moisture barrier layer sections will be located on the separation region. During the roll-to roll process, the continuous flexible module base may first be provided, in a continuous or stepwise manner, from a supply roll of a roll-to-roll module manufacturing system, and travels through a number of process stations, which add other components of the modules over the elongated protective sheet to form an embodiment of a continuous packaging structure or continuous multi-module device which may then be rolled onto a receiving spool to form a roll. A process of manufacturing another embodiment of a continuous packaging structure 250 will be described using the exploded view of the continuous packaging or module structure 250 shown in Figures 13A and 13B. It should be noted that details of solar cell interconnection and wiring and terminals of the module structure are not shown to simplify the drawing.
[0069] Initially, a section of the top elongated protective sheet 251 having a back surface
251A and two edges 252 is provided, as shown on Figure 13A. The top elongated protective sheet 251 forms the front side or the light receiving side of the modules that will be manufactured using the processes of the invention and therefore it is transparent.
[0070] In a second process step, a moisture barrier layer 253 is deposited on the back surface
25 IA of the top elongated protective sheet 251. The moisture barrier layer 253 includes moisture barrier layer portions 253 A or sections, and it only covers module spaces 258. In other words, the moisture barrier layer 253 is deposited and formed only on the predetermined locations referred to as module spaces 258 on the back surface 251A of the top elongated protective sheet 251. Figure 13B shows the module spaces 258 as dotted line rectangles which are the footprints of the interiors of future modules that will be manufactured as described herein, on the back surface 25 IA of the top elongated protective sheet 251. The top elongated protective sheet 251 and the moisture barrier layer 253, which comprises moisture barrier layer portions 253A, form a continuous flexible module base 250A. In one embodiment, initially, the continuous flexible module base 250A is provided at the first step of the roll-to roll process. Next, a moisture sealant 254 is applied on the back surface 25 IA of the top elongated protective sheet 251. The moisture sealant 254 contacts a moisture sealant region 254A, also referred to as a separation region, on the back surface 25 IA making a good mechanical bond with the back surface 25 IA at that location. Figure 13B shows the moisture sealant region 254A or the separation region surrounding the module spaces 258. When deposited on the moisture sealant region 254A, the moisture sealant 254 surrounds the moisture barrier layer portions 253 A on the module spaces 258 and is preferably deposited along the two edges 252 of the protective sheet 251 and between the moisture barrier portions 253 A on the module spaces 258. The portion of the moisture sealant 254 deposited along the edges 252 of the top elongated protective sheet 251 forms a side sealant 256 or side wall and the portion of the moisture sealant disposed between the module spaces 258 or ends of the module spaces forms a divider sealant 257 or divider wall. It should be noted that placement of the moisture sealant 254 on the separation region 254A, which does not have a moisture barrier layer, assures good mechanical bond between the moisture sealant 254 and the back surface 25 IA at the separation region 254A. Such mechanical bond is necessary for the moisture sealant to be effective. Moisture sealants placed on moisture barrier layers often don't form good mechanical bonds and moisture can diffuse fast through such weak interfaces even though the moisture sealant itself may be a good moisture barrier. [0071] As described above, the moisture sealant 254 may be in the form of a tape or a pre- shaped layer or it may be a viscous liquid that may be dispensed onto the moisture sealant region 254A of the back surface 25 IA of the top elongated protective sheet 251. When applied on the moisture sealant region 254A on the back surface 25 IA, the side walls 256 and the divider walls 257 of the moisture sealant 254 form a plurality of cavities 259 on the top elongated protective sheet 251. Each cavity 259 may be defined by one moisture barrier layer portion 253A and the side walls 256 and divider walls 257 that surround that moisture barrier layer portion 253A. As mentioned above, the moisture sealant 254 may be formed as a single piece continuous frame (moisture barrier frame) including the side walls and the divider walls that are shaped and dimensioned according to the desired solar module shape and size. When the moisture barrier frame is applied on the moisture sealant region 254A on the back surface 25 IA of the top elongated protective sheet 251, it forms the cavities 259 over the moisture barrier layer portions 253A. It should be noted that although substantially placed on the moisture sealant region 254A, some portion of the moisture sealant 254 may extend onto the moisture barrier layer portions 253A along their edges.
[0072] After disposing the moisture sealant 254, support material layers 260 or encapsulants and solar cells 262 or solar cell strings comprising two or more solar cells are placed over each moisture barrier layer portion 253 A within the cavities 259. In Figure 13 A, at least one solar cell 262 or solar cell string or circuit (in dotted lines) is shown interposed between the support material layers 260. As mentioned above, the solar cells 262 or the solar cell strings or the circuits are placed over the support material layer 260 in a face-down manner. A light receiving side of each solar cell 260 or solar cell string or circuit faces toward the elongated top protective sheet 251. Electrical leads (not shown) or terminals of the module may preferably be taken out of the cavity 259 through the side wall 256 of the moisture sealant 254 disposed along at least one of the long edges of the elongated protective sheet 251, in a way that the moisture sealant 254 also seals around the electrical leads. As shown in the previous embodiments, solar cell strings or circuits include solar cells 263 that are electrically interconnected. However, the strings in each of the cavities 259 may or may not be electrically interconnected to one another.
[0073] Referring back to Figure 13A, in the following step, a back elongated protective sheet
271 is placed on the moisture sealant 254 and over the support material 260 to complete the assembly of the components of a continuous packaging structure 250 before the lamination process. The back elongated protective sheet 271 may or may not be transparent. Figure 13C shows a cross- section view of the completed structure of the continuous packaging structure 250 after lamination, with modules 270, the cross section being taken along the middle of the illustrated continuous packaging structure 250. It should be noted that the back elongated protective sheet 271 may have moisture barrier characteristics. There are such sheets in the market which have multi layer polymeric structures including a metallic layer, such as aluminum, as a moisture barrier. Alternatively, another set of moisture barrier layer portions 253A may be coated on a front surface 271B of the back elongated protective sheet 271 just like the barrier layer portions on the top elongated protective sheet 251. [0074] Figures 12A and 12B described above show a general module structure employing various teachings of the present inventions, more simplified module structures will now be described below in connection to Figures 14A, 14B, 15, 16, 17, 18 and 19 to explain its unique features and benefits.
[0075] Figures 14A and 14B show a solar cell module 101 including at least two solar cell units, a first solar cell unit 102 and a second solar cell unit 104. The units 102 and 104 may be strings of solar cells. The unit 102 may include solar cells 102A, 102B and 102C, and the unit 104 may include solar cells 104A, 104B and 104C. Each solar cell includes a light receiving front portion 105A and a back portion 105B or base. The light receiving front portions of the solar cells form the front side of the solar cell units 102 and 104, while the back portions form the back side of the solar cell units. Solar cells in each unit or string are electrically interconnected to one another using conductive interconnects (not shown for clarity) by utilizing processes, such as soldering or gluing, that are well known in the field. As shown in Figures 14A-14B the module 101 has a multisection structure with a first section 106 A and a second section 106B. The first section 106 A includes the first string 102 and the second section 106B includes the second string 104. The sections are formed between a top protective sheet 107 and a back protective sheet 108 of the module 101. A first sealant 112 or an edge sealant seals the edges of the protective sheets at their perimeter thereby forming a protective shell 110. A second sealant 114 or a divider sealant separates the strings 102 and 104 thereby forming the sections 106 A and 106B. Both the edge sealant 112 and the divider sealant are disposed between and attached to the front and back protective sheets 107 and 108 as in the manner shown in Figures 14A and 14B. The edge and the divider sealants may be two parts of a single piece sealant.
[0076] In this embodiment, each solar cell string is encapsulated with a support material layer 116. The support material 116 such as EVA may fully fill the sections 106A and 106B which are sealed by the edge sealant 112 and the divider sealant 114 and the first and second protective sheets 107 and 108. Separately sealed sections independently protect the solar cell strings encapsulated within them by the support material 116. This provides extra protection to the solar cell strings. For example, even if a defect in the edge sealant 112 near the first section 106 A allows moisture to leak into the first section 106A and causes malfunction of the first string 102, the second string 104 in the second section 106 B, which is sealed, can still function and produce power. It should be noted that as the number of individually sealed sections within a module structure increases, probability of solar cell failure due to a defect in the protective shell decreases. The defects may be in the edge sealant or even in either one of the front protective sheet and the back protective sheet. If a defect in the protective shell brings moisture into a sealed section, the moisture gets trapped in that sealed section without ability to diffuse through the rest of the module structure. The solar cell module 101 of Figure 14A may, for example, have six sections instead of the two that is shown. In this case, each of the solar cells 102A, 102B, 102C, 104A, 104B and 104C may be in a section of its own.
[0077] A four section module design is shown in Figure 18. The module 150 of Figure 18 comprises six cells, 15 IA, 15 IB, 151C, 15 ID, 15 IE, and 15 IF, all of which may be similar in design. The solar cell design is shown in Figure 19. The solar cell 15 IA comprises a busbar 160 and fingers 161. These design details of the solar cells are not shown in Figure 18 to simplify the drawing. The module 150 has a four-section structure, each of the four sections 152A, 152B, 152C and 152D containing one half portion of three cells. For example, section 152 A contains a portion of cell 15 IA, a portion of cell 15 IB and a portion of cell 151C. Sections 152A, 152B, 152C and 152D are formed by the edge sealant 155 and the divider sealants 156 which comprises three divider sealant portions 156A, 156B and 156C. The divider sealant portions 156A and 156C are substantially aligned with the busbars 160 of the solar cells 15 IA, 15 IB, 151C, 15 ID, 15 IE, and 15 IF, so that shadowing losses due to the divider sealant portions 156A, 156B and 156C are minimized.
[0078] As depicted in Figure 12A and Figure 18, there is merit for forming sealed sections in the module structure where each section contains only a portion of a solar cell. This way, if moisture or other vapors enter into a section and damages a portion of a solar cell, other portions of the solar cell contained in other sections that are not affected by the moisture would continue producing power efficiently. This way, the overall performance of the module structure would be enhanced compared to a module without the sections. The edge sealant and divider sealants are materials that are highly resistive to moisture penetration. The water vapor transmission rate of the edge and divider sealants is preferably below 0.001 gm/m2/day, more preferably below 0.0001 gm/m2/day. [0079] A method of manufacturing an embodiment of the solar module 101 will be described in connection to Figure 15. Initially, a pair of front support layers 116A is placed on an inner surface 107B of the front protective sheet 107 which is pre-cleaned. Sealant spaces 118 are left between the edge of the protective sheet 107 and between the front support layers 116A to accommodate the edge sealant and the divider sealant described above. In the following step, the front portion 105A of the solar cell strings 102 and 104 may be placed on the front support layers 116A. Then, the back support layers 116B are placed on the back sides 105B of the solar cell strings 102 and 104. The edge sealant 112 and the divider sealant 114 are attached to the sealant spaces 118. Finally, an inner surface 108B of the back protective sheet 108 is placed over the back support layers 116B and over the edge and divider sealants. The front protective sheet 107 is typically a glass, but may also be a transparent flexible polymer film such as TEFZEL®, or another polymeric film with moisture barrier coatings. TEDLAR® and TEFZEL® are brand names of fluoropolymer materials from DuPont. TEDLAR® is polyvinyl fluoride (PVF), and TEFZEL® is ethylene tetrafluoroethylene (ETFE) fluoropolymer. The back protective sheet 108 may be a sheet of glass or a polymeric sheet such as TEDLAR®, or another polymeric material which may or may not be transparent. The back protective sheet 108 may comprise stacked sheets comprising various material combinations such as metallic films as moisture barrier. The front and back support layer materials may preferably include EVA or thermoplastic polyurethane (TPU) material or both. It should be noted that the thicknesses of the components shown in the figures are not to scale. The module 101 may have a rectangular or any other geometrical shape, and thus the size of the sections and the distribution of the solar cell strings may be arranged accordingly. It is also possible that either one or both of the front support layer and the back support layer may be eliminated from the module structures.
[0080] The stacked components of the solar cell module depicted in Figure 15 are placed in a laminator and heat treated for about 10-20 minutes in a temperature range of 120°- 1600C under pressure. This can alternatively be achieved through roll-to-roll lamination. As shown in Figures 14B and 15, each solar cell includes a front portion and a back portion or base. The base 105B includes a substrate and a contact layer formed on the substrate. A preferred substrate material may be a metallic material such as stainless steel, aluminum or the like. An exemplary contact layer material may be molybdenum. The front portion 105 A may include an absorber layer, such as a CIGS absorber layer which is formed on the contact layer, and a transparent layer, such as a buffer- layer/ZnO stack, formed on the absorber layer. An exemplary buffer layer may be a (Cd5Zn)S layer. Conductive fingers (not shown) may be formed over the transparent layer. Each interconnect electrically connects the substrate or the contact layer of one of the cells to the transparent layer of the next cell. However, the solar cells may be interconnected using any other method known in the field. [0081] Figure 16 shows another embodiment of the module 101 in side view. In this embodiment, the strings 102 and 104 are supported by the edge and divider sealants 112 and 114. Gaps 122 are left between the back side of the strings and the back protective sheet 108 and between the front side of the strings and the front protective sheet 107. Within the sections 106A and 106B, the edges of the strings 102 and 104 are held in place and sealed by the edge and divider sealants 112 and 114 as in the manner shown in Figure 16. It is possible to fill any of the gaps 122 with a support layer (not shown) identified as support layer 116A or 116B in Figure 15. [0082] Figure 17 shows yet another embodiment of the module 101 in side view. In this embodiment, a gap 122A is present over the front side of the strings 102 and 104. The gap 122A may optionally be filled with a front support layer (not shown but similar to the front support layer 116A of Figure 15). The back sides of the strings 102 and 104 are placed on the back sheet 108. The edges of the strings 102 and 104 are held in place and sealed by the edge and the divider sealants 112 and 114 as in the manner shown in Figure 17.
[0083] Although aspects and advantages of the present inventions are described herein with respect to certain preferred embodiments, modifications of the preferred embodiments will be apparent to those skilled in the art.

Claims

I claim:
1. An apparatus comprising: a continuous flexible sheet for use in fabricating flexible solar cell modules, the continuous flexible sheet including: a front surface and a back surface, one of the front surface and the back surface including at least two moisture barrier regions and a separation region, wherein the separation region surrounds each moisture barrier region and physically separates adjacent moisture barrier regions; and a moisture barrier layer formed on each of the moisture barrier regions but not on the separation region.
2. The apparatus of Claim 1 wherein the elongated protective sheet is transparent to visible light.
3. The apparatus of Claim 2 wherein the at least two moisture barrier layers are transparent to visible light.
4. The apparatus of Claim 3 wherein the at least two moisture barrier layers consists of an inorganic material with a water vapor transmission rate of smaller than 10"3 grams/meter square/day.
5. The apparatus of Claim 4 wherein the inorganic material consists of at least one of alumina, alumina silicate, a silicate, and a nitride.
6. An apparatus comprising: a monolithically integrated multi-module power supply, the monolithically integrated multi- module power supply including: a top transparent elongated protective sheet having a top sheet inner surface and a top sheet outer surface; a bottom elongated protective sheet having a bottom sheet inner surface and a bottom sheet outer surface; a moisture sealant disposed between the bottom sheet inner surface and the top sheet inner surface to form at least two sealed chambers, wherein each sealed chamber includes a ceiling formed by a portion of the top sheet inner surface and a floor formed by a portion of the bottom sheet inner surface, and wherein the moisture sealant is in physical contact with the top sheet inner surface and the bottom sheet inner surface; a moisture barrier layers covering each of the ceilings of each of the sealed chambers; at least two solar cells that are electrically interconnected and disposed in each of the at least two sealed chambers, each solar cell having a front light receiving side and a back side wherein the front light receiving side faces the top transparent elongated protective sheet; and a support material that at least partially encapsulates each solar cell on both the front light receiving side and the back side.
7. The apparatus of claim 6, further including moisture barrier layers covering the floors of the at least two sealed chambers.
8. The apparatus of claim 7, wherein the bottom elongated protective sheet is transparent.
9. The apparatus of claim 6, wherein the bottom elongated protective sheet comprises a moisture barrier film.
10. A method of manufacturing a photovoltaic module comprising the steps of: providing a transparent elongated protective sheet having a front surface and a back surface, the back surface including two or more moisture barrier regions and a separation region, wherein the separation region surrounds each moisture barrier region and physically separates adjacent moisture barrier regions; forming a moisture barrier layer on each moisture barrier region but not on the separation region; disposing a solar cell circuit over each of the moisture barrier layers, each solar cell circuit including a front light receiving side and a back substrate side; disposing a moisture sealant onto the separation region thereby forming two or more cavities, each cavity being at a location corresponding to the two or more moisture barrier regions, each cavity holding one solar cell circuit with the front light receiving side facing the transparent elongated protective sheet; at least partially covering each solar cell circuit with a support material on both the front light receiving side and the back substrate side; placing a second protective sheet over the support material and the moisture sealant to enclose the at least two cavities and to form a stack; and heating the stack to form the photovoltaic module.
11. The method of Claim 10 wherein the transparent elongated protective sheet is transparent to visible light.
12. The method of Claim 11 wherein the two or more moisture barrier layers are transparent to visible light.
13. The method of Claim 12 wherein the two or more moisture barrier layers consist of an inorganic material with a water vapor transmission rate of smaller than 10"3 grams/meter square/day.
14. The method of Claim 13 wherein the inorganic material consists of at least one of alumina, alumina silicate, a silicate, and a nitride.
15. A photovoltaic module comprising: a first protective sheet; a second protective sheet; an edge sealant disposed between the first and second protective sheets and continuously along an edge, the edge sealant, the first protective sheet and the second protective sheet thereby defining a moisture resistant protective shell; at least one solar cell, having a front light receiving side and a back substrate side, disposed within the moisture resistant protective shell; a support material that at least partially encapsulates the at least one solar cell on both the front light receiving side and the back substrate side of the solar cell; and a divider sealant disposed between the first and second protective sheets and within the moisture resistant protective shell, wherein the divider sealant divides the moisture resistant protective shell into at least two moisture resistant sealed sections, and wherein the edge sealant and the divider sealant are resistive to moisture transmission, and wherein the edge sealant and the divider sealant are made from material and constructed so that a water vapor transmission rate through each of the edge sealant and the divider sealant is less than 0.001 gm/m2/day.
16. The photovoltaic module of Claim 15, wherein the at least one solar cell includes a first solar cell and a second solar cell that is electrically interconnected to the first solar cell.
17. The photovoltaic module of Claim 16, wherein each of the at least two moisture resistant sealed sections contains at least one of the first solar cell and the second solar cell that is electrically interconnected to the first solar cell.
18. The photovoltaic module of Claim 16, wherein a first support material encapsulates the first solar cell forming a first encapsulated solar cell, and a second support material encapsulates the second solar cell thereby forming a second encapsulated solar cell.
19. The photovoltaic module of Claim 18, wherein each of the at least two moisture resistant sealed sections contain one of the first encapsulated solar cell and the second encapsulated solar cell that is electrically interconnected to the first encapsulated solar cell.
20. The photovoltaic module of Claim 16, wherein a divider sealant space is located on at least one of the first solar cell and the second solar cell..
21. The photovoltaic module of Claim 20, wherein the support material encapsulates the first solar cell and the second solar cell and wherein the divider sealant space is free of and excludes the support material.
22. The photovoltaic module of Claim 21, wherein at least a portion of the divider sealant is disposed on the divider sealant space located on at least one of the first and second solar cells
23. The photovoltaic module of Claim 22, wherein the at least two moisture resistant sealed sections each contain at least a portion of the at least one of the first solar cell and the second solar cell.
24. The photovoltaic module of Claim 23, wherein the portion of the divider sealant is aligned with a busbar of the at least one of the first and second solar cells.
25. The photovoltaic module of Claim 23, wherein the divider sealant is disposed on at least one of the front light receiving side and the back substrate side of at least one the first solar cell and the second solar cells.
26. The photovoltaic module of Claim 15, wherein at least a portion of the divider sealant is disposed on the at least one solar cell so that at least one of the moisture resistant sealed sections contains at least one portion of the at least one solar cell and the support material encapsulating the at least one portion of the at least one solar cell.
27. The photovoltaic module of Claim 26, wherein the portion of the divider sealant is disposed on at least one of the front light receiving side and the back substrate side of the at least one solar cell.
28. The photovoltaic module of Claim 27, wherein the portion of the divider sealant is aligned with a busbar of the at least one solar cell.
29. The photovoltaic module of Claim 15, wherein the support material is a transparent polymeric material.
30. The photovoltaic module of Claim 15, wherein the first protective sheet includes one of a moisture barrier flexible polymeric film and glass.
31. The photovoltaic module of Claim 30, wherein the second protective sheet includes one of a moisture barrier flexible polymeric film and glass.
32. The photovoltaic module of Claim 15, wherein the solar cells are Group IBIIIAVIA thin film solar cells with stainless steel substrate.
33. The photovoltaic module of Claim 32 wherein the front protective sheet and the back protective sheet are flexible.
34. A method of manufacturing a solar cell module comprising the steps of: disposing at least one solar cell over a first protective sheet, the at least one solar cell including a front light receiving side and a back substrate side; disposing an edge sealant along the edges of the first protective sheet, thereby forming a cavity holding the at least one solar cell; at least partially covering the at least one solar cell with a support material on both the front light receiving side and the back substrate side of the solar cell; disposing a divider sealant to divide the cavity into at least two cavity sections; and placing a second protective sheet over the support material, the edge sealant and the divider sealant to enclose the at least two cavity sections, wherein the moisture transmission rate through the edge sealant and the divider sealant is less than 0.001 gm/m2/day.
35. The method of Claim 34 further comprising applying heat and pressure to a resulting assembly of the protective sheets, at least one solar cell, sealant and the support material so as to laminate the solar cell units between the two protective sheets.
36. The method of Claim 35 further comprising cooling the resulting assembly so as to cause the support material to bond to the first and second protective sheets and to the at least one solar cell.
37. The method of Claim 34, wherein the at least one solar cell includes a first solar cell and a second solar cell that is electrically interconnected to the first solar cell.
38. The method of Claim 37, wherein each of the at least two cavity sections contains one of the first solar cell and the second solar cell that is electrically interconnected to the first solar cell.
39. The method of Claim 38, wherein the step of at least partially covering the at least one solar cell with the support material comprises sandwiching the first solar cell between a first set of layers of the support material, and sandwiching the second solar cell between a second set of layers of the support material.
40. The method of Claim 39, wherein the divider sealant is aligned with a busbar of the at least one of the first and second solar cells.
41. The method of Claim 37, wherein a divider sealant space is located on at least one of the first and second solar cells.
42. The method of Claim 41, wherein the step of at least partially covering the at least one solar cell with the support material comprises sandwiching the first solar cell between a first set of layers of the support material, and sandwiching the second solar cell between a second set of layers of the support material, wherein the divider sealant space is free of and excludes the support material.
43. The method of Claim 42, wherein the step of disposing the divider sealant comprises disposing at least a portion of the divider sealant on the divider sealant space located on at least one of the first and second solar cells.
44. The method of Claim 43, wherein the portion of the divider sealant is disposed on at least one of the front light receiving side and the back substrate side of at least one the first solar cell and the second solar cells.
45. The method of Claim 41, wherein the at least two cavity sections each contain at least a portion of at least one of the first solar cell and the second solar cell that is electrically interconnected to the first solar cell.
46. The method of Claim 34, wherein the step of disposing the divider sealant comprises disposing at least a portion of the divider sealant on the at least one solar cell so that at least one of the cavity sections contain at least one portion of the at least one solar cell and the support material covering the at least one portion of the at least one solar cell.
47. The method of Claim 46, wherein the portion of the divider sealant is disposed on at least one of the front light receiving side and the back substrate side of the at least one solar cell.
48. The method of Claim 46, wherein the portion of the divider sealant is aligned with a busbar of the at least one solar cell.
49. The method of Claim 34, wherein the support material is a transparent polymeric material.
50. The method of Claim 34, wherein the first protective sheet includes one of a moisture barrier flexible polymeric film and glass.
51. The method of Claim 50, wherein the second protective sheet includes one of a moisture barrier flexible polymeric film and glass.
52. The method of Claim 34, wherein the solar cells are Group IBIIIAVIA thin film solar cells with stainless steel substrate.
53. The method of Claim 52 wherein the solar cells, the front protective sheet and the back protective sheet are flexible.
54. A method of manufacturing a continuous multi-module power supply including a plurality of solar cell modules, comprising the steps of: providing a first elongated protective sheet including a plurality of designated module areas, which are located in an end-to-end fashion; applying a moisture barrier frame on the first elongated protective sheet surrounding the borders of the plurality of designated module areas, wherein the moisture barrier frame includes side walls disposed along the sides of the designated module areas and divider walls disposed between the adjacent designated module areas, wherein the first protective sheet, the side walls and the divider walls define a plurality of cavities; placing a solar cell string into each cavity, the solar cell string comprising two or more solar cells that are electrically interconnected and include a front light receiving side facing the first elongated protection sheet and a back substrate side; arranging two terminal wires with positive and negative polarity, with one end of each of the two terminal wires electrically connected to the solar cell string, and each of the two terminal wires extending through the moisture barrier frame so that another end of each of the two terminal wires extends outside the cavity and the moisture barrier frame; at least partially covering each of the solar cell strings with a support material on both the front light receiving side and the back substrate side; and placing a second elongated protective sheet over the support material and the moisture barrier frame to enclose the plurality of cavities, thereby forming a continuous elongated packaging structure including a plurality of solar cell modules.
55. . The method of claim 54 wherein the step of arranging arranges the two terminal wires such that each of the two terminal wires extends through at least one of the side walls of the moisture barrier frame.
56. The method of Claim 55 further comprising applying heat and pressure to the continuous elongated packaging structure with the solar cell modules to form a continuous multi-module device including a plurality of laminated solar cell modules that each have the two terminal wires that extend outside the side wall.
57. The method of Claim 56, wherein the step of applying heat and pressure is performed while the continuous elongated package is rolled between rollers and is thereby transformed into the continuous multi-module device.
58. The method of claim 57 wherein the process of rolling is performed in a vacuum environment.
59. The method of Claim 57, further comprising cutting the continuous multi-module device into sections, each section comprising one or more laminated solar cell modules wherein the step of cutting includes cutting through the divider walls between the laminated solar cell modules.
60. The method of Claim 59, further comprising serially electrically connecting the laminated solar cell modules within each section to form monolithically integrated multi-module power supplies.
61. The method of Claim 57, further including forming holes through the divider walls of the moisture barrier frame so as to allow the removal of entrapped air from the solar cell modules as the continuous elongated package is rolled between rollers.
62. A continuous multi-module power supply including a plurality of solar cell modules, comprising: a first elongated protective sheet having elongated edges and short edges and a second elongated protective sheet having elongated edges and short edges, at least the first elongated protective sheet being made of a light- trans parent material; at least two solar cell strings disposed between the first and second elongated protective sheets, each of the at least two solar cell strings comprising two or more solar cells that are electrically interconnected, and wherein each solar cell string includes a front side facing the first elongated protective sheet and a back side facing the second elongated protective sheet; a moisture barrier frame formed of a sealant disposed between the first and second protective sheets, wherein an edge of the moisture barrier frame is disposed between the first and second protective sheets and along the elongated and short edges at the perimeters thereof, and a divider of the moisture barrier frame is disposed between the first and second protective sheets and between each of the at least two solar cell strings; a support material that fills the moisture barrier frame and covers the front and back sides of the at least two solar cell strings in the moisture barrier frame thus forming at least two solar cell modules; and two terminal wires having positive and negative polarity connected to each of the at least two solar cell strings, wherein, for each of the at least two solar cell strings, one end of each of the two terminal wires is electrically connected to the solar cell string, each of the two terminal wires extend through the sealant so that another end of each of the two terminal wires extends outside the sealant.
63. The continuous multi-module power supply of claim 62 further including an interconnection wire disposed outside the at least two solar cell modules to electrically connect together some of the terminal wires.
64. The continuous multi-module power supply of Claim 62, wherein the other end of each of the two terminal wires extends outside the sealant by passing through the elongated edge of the moisture barrier frame between some of the elongated edges of the first and second protective sheets.
65. The continuous multi-module power supply of Claim 64, wherein the support material is a transparent polymeric material.
66. The continuous multi-module power supply of Claim 64, wherein the first elongated protective sheet includes a moisture barrier flexible polymeric film
67. The continuous multi-module power supply of Claim 66, wherein the second elongated protective sheet includes a moisture barrier flexible polymeric film.
68. The continuous multi-module power supply of Claim 64, wherein the at least two solar cell strings each include Group IBIIIAVIA thin film solar cells.
69. The continuous multi-module power supply of Claim 64 wherein the at least two solar cell strings, the front protective sheet and the back protective sheet are flexible.
PCT/US2009/053265 2008-08-11 2009-08-10 Flexible thin film photovoltaic modules and manufacturing the same WO2010019496A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP09807121A EP2319090A1 (en) 2008-08-11 2009-08-10 Flexible thin film photovoltaic modules and manufacturing the same

Applications Claiming Priority (10)

Application Number Priority Date Filing Date Title
US12/189,627 US8207440B2 (en) 2008-08-11 2008-08-11 Photovoltaic modules with improved reliability
US12/189,627 2008-08-11
US9762808P 2008-09-17 2008-09-17
US61/097,628 2008-09-17
US12/250,507 US20100031996A1 (en) 2008-08-11 2008-10-13 Structure and method of manufacturing thin film photovoltaic modules
US12/250,507 2008-10-13
US11708308P 2008-11-21 2008-11-21
US61/117,083 2008-11-21
US14594709P 2009-01-20 2009-01-20
US61/145,947 2009-01-20

Publications (1)

Publication Number Publication Date
WO2010019496A1 true WO2010019496A1 (en) 2010-02-18

Family

ID=41669223

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2009/053265 WO2010019496A1 (en) 2008-08-11 2009-08-10 Flexible thin film photovoltaic modules and manufacturing the same

Country Status (3)

Country Link
EP (1) EP2319090A1 (en)
TW (1) TW201017914A (en)
WO (1) WO2010019496A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011131345A1 (en) * 2010-04-21 2011-10-27 Muehlbauer Ag Method and device for producing a solar module with flexible thin-film solar cells and solar module comprising flexible thin-film solar cells
CH706582A1 (en) * 2012-05-31 2013-12-13 Iworks Ag Solar panel for solar system, has fold line that is provided between primary and secondary solar cells
EP3159937A1 (en) * 2015-10-22 2017-04-26 Eterbright Solar Corporation Flexible solar panel module
WO2017172056A1 (en) * 2016-03-30 2017-10-05 Exxonmobil Chemical Patents Inc. Photovoltaic module back sheets comprising thermoplastic vulcanizate compositions
WO2018049878A1 (en) * 2016-09-14 2018-03-22 海口未来技术研究院 Solar cell assembly and aerostat
CN115000236A (en) * 2022-04-22 2022-09-02 山西漳山发电有限责任公司 Photovoltaic module laminating machine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9718096B2 (en) 2013-08-19 2017-08-01 Board Of Regents, The University Of Texas System Programmable deposition of thin films of a user-defined profile with nanometer scale accuracy
WO2015026735A1 (en) * 2013-08-19 2015-02-26 Board Of Regents, The University Of Texas System Programmable deposition of thin films of a user-defined profile with nanometer scale accuracy
TWI686053B (en) * 2018-11-26 2020-02-21 財團法人工業技術研究院 Solar cell panel and solar cell module

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4754544A (en) * 1985-01-30 1988-07-05 Energy Conversion Devices, Inc. Extremely lightweight, flexible semiconductor device arrays
US5478402A (en) * 1994-02-17 1995-12-26 Ase Americas, Inc. Solar cell modules and method of making same
US5728230A (en) * 1995-08-15 1998-03-17 Canon Kabushiki Kaisha Solar cell and method for manufacturing the same
US7150938B2 (en) * 2001-03-30 2006-12-19 Lithium Power Technologies, Inc. Structurally embedded intelligent power unit
US20070295388A1 (en) * 2006-05-05 2007-12-27 Nanosolar, Inc. Solar assembly with a multi-ply barrier layer and individually encapsulated solar cells or solar cell strings

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4754544A (en) * 1985-01-30 1988-07-05 Energy Conversion Devices, Inc. Extremely lightweight, flexible semiconductor device arrays
US5478402A (en) * 1994-02-17 1995-12-26 Ase Americas, Inc. Solar cell modules and method of making same
US5728230A (en) * 1995-08-15 1998-03-17 Canon Kabushiki Kaisha Solar cell and method for manufacturing the same
US7150938B2 (en) * 2001-03-30 2006-12-19 Lithium Power Technologies, Inc. Structurally embedded intelligent power unit
US20070295388A1 (en) * 2006-05-05 2007-12-27 Nanosolar, Inc. Solar assembly with a multi-ply barrier layer and individually encapsulated solar cells or solar cell strings

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011131345A1 (en) * 2010-04-21 2011-10-27 Muehlbauer Ag Method and device for producing a solar module with flexible thin-film solar cells and solar module comprising flexible thin-film solar cells
CH706582A1 (en) * 2012-05-31 2013-12-13 Iworks Ag Solar panel for solar system, has fold line that is provided between primary and secondary solar cells
EP3159937A1 (en) * 2015-10-22 2017-04-26 Eterbright Solar Corporation Flexible solar panel module
CN106612101A (en) * 2015-10-22 2017-05-03 上银光电股份有限公司 Flexible solar panel module
WO2017172056A1 (en) * 2016-03-30 2017-10-05 Exxonmobil Chemical Patents Inc. Photovoltaic module back sheets comprising thermoplastic vulcanizate compositions
WO2018049878A1 (en) * 2016-09-14 2018-03-22 海口未来技术研究院 Solar cell assembly and aerostat
CN115000236A (en) * 2022-04-22 2022-09-02 山西漳山发电有限责任公司 Photovoltaic module laminating machine
CN115000236B (en) * 2022-04-22 2024-01-30 山西漳山发电有限责任公司 Photovoltaic module laminating machine

Also Published As

Publication number Publication date
EP2319090A1 (en) 2011-05-11
TW201017914A (en) 2010-05-01

Similar Documents

Publication Publication Date Title
US20100031997A1 (en) Flexible thin film photovoltaic modules and manufacturing the same
US20100031996A1 (en) Structure and method of manufacturing thin film photovoltaic modules
US20110239450A1 (en) Roll-to-roll manufacturing of flexible thin film photovoltaic modules
US8207440B2 (en) Photovoltaic modules with improved reliability
EP2319090A1 (en) Flexible thin film photovoltaic modules and manufacturing the same
US20120318318A1 (en) Cigs based thin film solar cells having shared bypass diodes
US20100147364A1 (en) Thin film photovoltaic module manufacturing methods and structures
US20110168238A1 (en) Flexible solar modules and manufacturing the same
US20120048349A1 (en) Flexible solar modules and manufacturing the same
US20120152349A1 (en) Junction box attachment for photovoltaic thin film devices
US20120318319A1 (en) Methods of interconnecting thin film solar cells
US20100175743A1 (en) Reliable thin film photovoltaic module structures
US9385255B2 (en) Integrated thin film solar cell interconnection
US20120152327A1 (en) Method of manufacturing solar modules
US20120125391A1 (en) Methods for interconnecting photovoltaic cells
US20090260675A1 (en) Encapsulation of solar modules
US20110083716A1 (en) Monolithic module assembly using back contact solar cells and metal ribbon
US20120325282A1 (en) Solar cells with grid wire interconnections
US20060213548A1 (en) Scalable photovoltaic cell and solar panel manufacturing with improved wiring
WO2013122757A1 (en) Photovoltaic module containing shingled photovoltaic tiles and fabrication processes thereof
CN102362352B (en) Optoelectronic device
US20120125393A1 (en) Photovoltaic Device and Method and System for Making Photovoltaic Device
US20120133012A1 (en) Composite system for photovoltaic modules
US20190027624A1 (en) Flexible photovoltaic apparatus
WO2022130153A1 (en) Large-area solar module via continuous additive lamination method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09807121

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2009807121

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: DE