CN220569691U

CN220569691U - Connecting piece and solar cell module

Info

Publication number: CN220569691U
Application number: CN202321847740.XU
Authority: CN
Inventors: 段野; 吴颐良; 叶亚宽; 弓志明; 郭清秀
Original assignee: Beijing Yaoneng Technology Co ltd
Current assignee: Beijing Yaoneng Technology Co ltd
Priority date: 2023-07-13
Filing date: 2023-07-13
Publication date: 2024-03-08
Anticipated expiration: 2033-07-13

Abstract

A connecting piece and a solar cell module relate to the technical field of cell interconnection. The connecting piece comprises a plurality of wires which are arranged in parallel; the first membrane and the second membrane are used for fixing a plurality of wires, the plurality of wires are clamped between the first membrane and the second membrane, and the first membrane and the second membrane are respectively positioned at the first end and the second end of the wires; first ends of the plurality of wires are partially embedded into the first membrane, and a first exposed part is formed in a region corresponding to the first membrane; the second ends of the plurality of wires are partially embedded in the second membrane to form a second exposed portion in a region corresponding to the second membrane. The scheme can replace the conventional welding strip interconnection process. The end part of the connecting piece can replace a grid line structure to collect collector current, and the whole connecting piece can replace a welding strip to realize interconnection among battery units, so that the battery preparation process and the assembly process are simplified, and the problems of high cost of low-temperature silver paste, and relatively poor conductivity of a main grid and an auxiliary grid of low-temperature paste screen printing due to lack of a high-temperature sintering process in the prior art are solved.

Description

Connecting piece and solar cell module

Technical Field

The invention relates to the technical field of solar cell interconnection, in particular to a connecting piece and a solar cell module.

Background

Solar cells are devices that directly convert light energy into electrical energy through the photovoltaic effect. Because a single solar cell cannot be directly used as a power source, in a practical application process, it is necessary to connect a plurality of solar cells into a cell string and connect the cell string into a solar cell module of a desired model through a solder ribbon or bus bar. When the solar battery unit is connected by adopting the welding strip, the welding temperature is high, so that the battery is easy to warp and crack, and the reliability of the assembly is influenced; meanwhile, the high temperature in the welding process can affect the battery performance, especially the perovskite battery with higher temperature sensitivity.

When a transparent conductive oxide film is prepared on the surface of a battery as a transparent electrode, silver metal electrodes with a main grid line and a secondary grid line structure are generally prepared on the solar battery in a screen printing and low-temperature curing mode, and battery units are connected in series into a battery string in a welding mode. However, the curing temperature of the low-temperature curing slurry is still about 180 ℃ to 200 ℃, the curing time is about 10 minutes to 20 minutes, and the perovskite battery with high temperature sensitivity forms a great challenge.

The low-temperature silver paste is basically dependent on import at present, has high cost, obviously increases the cost of the battery and is not beneficial to wide production and use. Moreover, the main grid and the auxiliary grid of the low-temperature slurry screen printing are relatively poor in conductivity and connection reliability due to the lack of a high-temperature sintering process. Thus, there is a need for a reliable connection scheme for battery cells that is compatible with low temperature process requirements, such as perovskite batteries, and that does not rely on low temperature silver paste.

Disclosure of Invention

The invention aims to provide a connecting piece and a solar cell module, which are used for solving the problems of high temperature and unreliable electrode extraction mode required in the preparation process of the solar cell and the module in the prior art and are suitable for mass production.

In a first aspect, embodiments of the present invention provide a connector for connecting at least two solar cells in series, including a plurality of wires arranged in parallel;

the first membrane and the second membrane are used for fixing the plurality of wires, the plurality of wires are clamped between the first membrane and the second membrane, and the first membrane and the second membrane are respectively positioned at the first end and the second end of the plurality of wires;

first ends of the plurality of wires are partially embedded into the first membrane, and a first exposed part which corresponds to and is electrically connected with the first electrode of the first battery unit is formed in a region corresponding to the first membrane; the second ends of the plurality of wires are partially embedded in the second membrane, and a second exposed portion corresponding to and electrically connected with the second electrode of the second battery cell is formed in a region corresponding to the second membrane.

In some embodiments, the connector is further configured to connect the end-to-end battery cells of the battery string with the bus bar, wherein the first exposed portion or the second exposed portion of the connector comprises: a body portion for crimping on the first electrode or the second electrode, and an extension portion for electrically connecting with a bus bar.

Alternatively, the connector further includes: the third diaphragm is arranged at the edge of the first diaphragm or the second diaphragm; the plurality of wires extend to and are partially embedded in the third membrane, and exposed extension portions for corresponding and electrically connecting with the bus bars are formed at the areas corresponding to the third membrane.

Optionally, the wire comprises a metal wire core, and a wire coating for blocking ion migration; the wire coating is at least distributed at the part of the metal wire core, which is contacted with the electrode layer of the solar cell unit.

Optionally, the wire coating is distributed on the outer peripheral surface of the metal wire core.

Optionally, the material of the wire coating is conductive ceramic.

Preferably, the material of the wire coating is any one of TiN, tiC, tiCN, tiSiN, alTiN, zrN, taN, hfN.

Optionally, the wire coating is formed on the surface of the metal wire core by forming a dense film through cathodic arc or magnetron sputtering.

Optionally, the wire coating is a microcrystalline film, which is a microcrystalline film with a crystal orientation of (111).

Optionally, the thickness of the wire coating is 0.01-5 μm. Preferably, the thickness of the wire coating is 0.1-0.2 μm.

Optionally, a third portion covered by the first membrane and the second membrane simultaneously exists in the middle of the plurality of wires, and the third portion corresponds to the interval between the battery units.

Optionally, the plurality of wires are distributed in groups, and each group of wires corresponds to a row of battery cells. Alternatively, the line width of the wire is 30 to 140 μm, preferably 75 to 85 μm. Alternatively, the spacing between adjacent two wires is 2-4 mm, preferably 2.5-3.5mm.

Alternatively, the cross-sectional shape of the wire is circular or triangular.

Optionally, the first membrane and the second membrane each comprise a release film and an adhesive film for adhering the wire to the release film.

Alternatively, the adhesive film has a glass transition temperature lower than that of the release film.

Optionally, the material of the adhesive film is selected from at least one of polyolefin thermoplastic elastomer, polyvinyl alcohol Ding Quanzhi and ethylene-vinyl acetate copolymer; and/or the material of the isolating film is at least one selected from the group consisting of a polyterephthalic acid resin, polyvinylidene fluoride and polytetrafluoroethylene.

Optionally, the thickness of the adhesive film is less than the diameter of the wire.

Alternatively, the adhesive film has a thickness of 20-70 μm.

Alternatively, the thickness of the separator is 1-100 μm. The thickness of the separator is preferably 10 to 80. Mu.m.

The present application also provides another connector for connecting a solar cell string with a bus bar. The connector comprises: a plurality of wires arranged in parallel; the membrane is used for fixing the plurality of wires, the plurality of wires are partially embedded in the membrane to form an exposed part, the exposed part comprises a main body part and an extension part, the main body part is used for corresponding and electrically connecting with electrodes of a third battery unit, and the extension part is used for electrically connecting with a bus bar, and the third battery unit is used for starting or ending a battery unit of the solar battery string.

In a second aspect, the present application also provides a solar cell module comprising the connector provided in the first aspect; alternatively, the solar cell module includes:

at least one battery string, wherein the battery string comprises at least two battery units, the two battery units are connected in series through a plurality of mutually parallel wires, first ends of the plurality of wires are pressed at a first electrode of the first battery unit, and second ends of the plurality of wires are pressed at a second electrode of the second battery unit;

A first membrane disposed above the battery string, and a second membrane disposed below the battery string; the battery string, the first membrane and the second membrane are bonded to each other.

Optionally, the battery unit is a perovskite/crystalline silicon laminated battery, the first electrode of the first battery unit is a transparent top electrode of a perovskite subcell, and the second electrode of the second battery unit is a metal bottom electrode of a crystalline silicon subcell.

Optionally, the wire comprises a metal wire core, and a wire coating for blocking ion migration; the wire coating is at least distributed at the contact part of the metal wire core and the electrode layer.

The first membrane and the second membrane each include a release film and an adhesive film, the plurality of wires being partially embedded in the adhesive film.

Optionally, the glass transition temperature of the adhesive film is lower than the glass transition temperature of the release film.

Optionally, a packaging film is further arranged on one side of the isolating film, which is far away from the adhesive film; the battery string, the first membrane and the second membrane are bonded together by a lamination process at the time of packaging.

The present application provides an integrated connector that can be prefabricated, which can be prefabricated prior to electrically connecting solar cells to form a battery string. The connecting piece can be fixed on the surface of the solar cell unit at a lower temperature through a pressing process, so that the solar cell unit is connected in series, high-temperature welding is not needed, and the influence of high-temperature welding on the performance of the solar cell unit is avoided. In addition, the connecting piece can be prefabricated, can be produced in a large scale in advance and then is directly pressed on the battery unit in the assembly process, is suitable for industrial large-scale production, is favorable for reducing the process of series connection of solar battery assemblies, and improves the production efficiency. Meanwhile, the conducting wires in the connecting piece provided by the application have the effect of the grid lines, so that the electric connection of adjacent solar battery units can be realized, the battery strings can be formed, the effect of current confluence can be achieved, the silver paste grid lines are not required to be additionally arranged, namely, the solar battery does not need to carry out the silk-screen printing process of the main grid line and the auxiliary grid line, the high cost caused by low-temperature silver paste is reduced, meanwhile, the damage of the solar battery caused by the high-temperature process such as the silk-screen printing process and the like at the temperature of more than 200 ℃ is improved, the reliability of the solar battery is improved, the production cost is reduced, the industrial production is easy to realize, and the application prospect is good.

The invention adopts the connecting piece to realize a novel interconnection mode of the battery units, the battery units can be interconnected without a main grid and an auxiliary grid or a high-temperature welding process, and meanwhile, the current collection capacity which is close to or higher than that of the battery units with the main grid and the auxiliary grid is realized. In addition, the scheme can also avoid the problem of water blocking performance reduction caused by the phenomena of battery warpage and hidden cracking which are easily caused by welding of the welding strip and the problem of connection reliability reduction caused by unsintered low-temperature silver paste, so that the water blocking performance and reliability of the component package can be improved.

Drawings

Fig. 1 and fig. 2 are schematic structural diagrams of a connector according to some embodiments of the present application;

FIG. 3 is a schematic diagram of three crystal orientations of TiN when the TiN layer is used for the wire coating in the connector provided by the application;

FIG. 4 is a schematic cross-sectional view of a connector according to some embodiments of the present application;

FIG. 5 is an enlarged schematic view of a cross-sectional structure of one end of a connector according to some embodiments of the present disclosure;

fig. 6 is a schematic structural diagram of a connection between a solar cell and a connection member according to some embodiments of the present disclosure;

FIG. 7 is a side view of a connection with a solar cell unit provided by some embodiments;

Fig. 8-11 are schematic diagrams of connectors for connecting battery cells of a battery string with bus bars provided in some embodiments;

FIG. 12 is a graph showing the contact resistance of a copper wire with a titanium nitride coating on an ITO surface with conventional tin Bao Tongsi provided in some embodiments; wherein,

100-solar cell, 101-first cell, 102-second cell

200-connectors, 210-wires, 211-metal cores, 212-wire coatings, 221-first diaphragms,

222-second membrane, 223-adhesive film, 224-barrier film, 220-first exposed portion,

225-main body portion, 226-extension portion, 227-third diaphragm, 228-diaphragm.

Abbreviations and key terms used in the description herein

High-energy pulse magnetron sputtering (HiPIMS) is a magnetron sputtering technology which utilizes higher pulse peak power and lower pulse duty ratio to generate high sputtering metal ionization rate, and the technology can greatly improve the plasma density, thereby accelerating the film deposition rate and forming a high-quality film with compactness, smoothness and high adhesive force.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The present embodiment provides a connector 200 for connecting at least two solar cells 100 in series. Referring to fig. 1,4 and 5, the connector 200 includes: a plurality of wires 210 arranged in parallel, and a first membrane 221 and a second membrane 222 for fixing the plurality of wires 210. The plurality of wires 210 are sandwiched between the first membrane 221 and the second membrane 222, and the first membrane 221 and the second membrane 222 are respectively located at the first end and the second end of the plurality of wires 210.

First ends (left ends in the drawing) of the plurality of leads 210 are partially embedded in the first membrane 221, and a first exposed portion 220 (see fig. 8) corresponding to and electrically connected to the first electrode of the first battery cell 101 is formed at a region corresponding to the first membrane 221. A second end (e.g., a right end in the drawing) of the plurality of wires 210 is partially embedded in the second membrane 222, and a second exposed portion (not shown in the drawing due to shielding) corresponding to and electrically connected with the second electrode of the second battery cell 102 is formed in a region corresponding to the second membrane 222. The first exposed portion 220 is opposite to the second exposed portion and is staggered in position.

Wherein, the first electrode can be a top electrode or a bottom electrode; the second electrode may be a bottom electrode or a top electrode. And when the first electrode is a top electrode, the second electrode is a bottom electrode; when the first electrode is a bottom electrode, the second electrode is a top electrode. The top electrode is typically a transparent electrode and the bottom electrode is typically a metal electrode.

Preferably, one of the first electrode and the second electrode in this embodiment is a transparent top electrode, and the other is a transparent bottom electrode.

In the present application, the first membrane 221 is disposed on one side of the plurality of wires 210 (e.g. below the wires in fig. 1), and the upper surface of the first membrane 221 is connected to the plurality of wires 210; the lower surface of the second film 222 is disposed on the other side of the conductive lines 210 (e.g., above the conductive lines in fig. 1) and is connected to the conductive lines 210, and the vertical projection of the region where the first film 221 is connected to the conductive lines 210 (i.e., the first exposed portion) and the region where the second film 222 is connected to the conductive lines 210 (i.e., the second exposed portion) on the plane where the conductive lines 210 are located may not overlap each other.

Each of the leads 210 is connected at both ends thereof to the first membrane 221 and the second membrane 222, respectively, by means of partial embedding. Taking the example that the first membrane 221 and the second membrane 222 shown in fig. 1 are disposed on the upper side and the lower side of the plurality of wires 210, respectively: the first membrane 221 is connected to each conductive line 210 at the upper side of the membrane, the second membrane 222 is connected to each conductive line 210 at the lower side of the membrane, and each conductive line 210 is not completely embedded in the first membrane 221 and the second membrane 222, and the non-embedded portions (i.e., the first exposed portion and the second exposed portion) allow each conductive line 210 to be connected to the top electrode and the bottom electrode of two adjacent solar cells 100, respectively.

Since each wire 210 is not completely embedded in the first and second membranes 221 and 222, there are exposed portions of each wire surface that can be electrically connected to external components, and these exposed portions are marked as first and second exposed portions according to whether they correspond to the first membrane 221 or the second membrane 222.

The first exposed portion is the same size as or slightly smaller than the first electrode; the second exposed portion is the same size as or slightly smaller than the second electrode. In the implementation, the first electrode and the second electrode have the same size, and the sizes of the first exposed part and the second exposed part are the same.

The connection member is used to connect two (or two columns and a plurality of rows) of solar cells 100. When the connector is crimped onto two or more rows of solar cells 100, a first exposed portion 220 of the plurality of wires 210 is crimped onto the top electrode of one (or one row) of solar cells 100 and a second exposed portion is crimped onto the bottom electrode of an adjacent (or another row) of solar cells 100.

The top electrode/bottom electrode surfaces of the solar cell unit 100 have a plurality of conductive wire structures of the connection members, which are parallel or nearly parallel to each other, and since the conductive wires 210 themselves have conductivity, a current collecting effect can be achieved, so that the solar cell unit 100 can realize a current collecting effect without a process of preparing a grid line while equivalently replacing the grid line structure (or the main and auxiliary grid line structures) while connecting the cell units to form a cell string.

The top electrode of the first battery unit and the bottom electrode of the second battery unit can be connected together through the connecting piece, so that the first battery unit and the second battery unit are connected in series. If a third battery unit which is arranged in the same row with the first battery unit and the second battery unit is also arranged, the top electrode of the second battery unit and the bottom electrode of the third battery unit can be connected together through another connecting piece, so that the first battery unit, the second battery unit and the third battery unit are connected in series. Similarly, a row of battery units can be connected in series through a plurality of connecting pieces to form a series of battery strings connected in series.

Of course, the connector of the present application may also connect the first battery cell and the second battery cell in series by connecting the top electrode of the second battery cell with the bottom electrode of the first battery cell.

In some embodiments, a plurality of wires 210 are distributed in groups, each group of wires 210 corresponding to a row of battery cells, two battery cells of the row may be connected in series with each other in a modular process. In fig. 2, which shows a parallel conductor comprising two groups, two rows of battery cells can be implemented in series, and a plurality of connectors according to this embodiment can be used to form two rows of battery strings in series with each other. The connector shown in fig. 1 can be used to connect two battery cells in series, and a plurality of battery cells can be connected in series by using the connectors shown in fig. 1 to form a battery string as shown in fig. 7. The connector shown in fig. 2 can be used to connect two rows and two columns of battery cells in series in a row to form two rows of battery strings. Fig. 6 is a schematic diagram of a plurality of rows of battery cells connected in series in rows using connectors.

The connecting piece comprising a plurality of groups of parallel wires can be used for connecting a plurality of rows and two columns of battery units in series at the same time, so that each row forms a battery string. It will be appreciated by those skilled in the art that the connector of the present application may also connect two adjacent cells in the same column in series.

Further, by selecting the number of groups of parallel wires contained in the connecting piece and reasonably laying, the battery units in a plurality of rows and columns which are arranged in a matrix can be connected according to a string scheme of a designed battery string, and meanwhile, the grid line process can be omitted. The string arrangement of the battery strings is not limited to the same row or the same column. For example, two or more adjacent rows of battery cells may be connected in series to form a battery string by a connecting member. For example, a battery string may be formed by connecting one row of battery cells and the adjacent half row of battery cells in series through a connecting member.

In some embodiments, in the connection member, two adjacent sets of wires are spaced apart, and the distance D1 between the two adjacent sets of wires is related to the distance between two rows of the battery cells in the solar cell module design. Unnecessary short circuit between two rows of battery units can be avoided, and meanwhile, the connector with specific group number can be obtained conveniently through cutting. The width of each group of parallel wires corresponds to the electrode width of a battery unit, and the electrode width direction in the embodiment is perpendicular to the extending direction of the parallel wires in the connecting piece and the direction of the plane where the wires are located.

In some embodiments, the area of the first membrane 221 and the second membrane 222 with the plurality of wires 210 partially embedded is equal or nearly equal to the electrode area of the solar cell unit 100, so that the first membrane 221 and the second membrane 222 cover the top electrode/bottom electrode surface of the solar cell unit 100 as much as possible, and the wires 210 corresponding to the connectors may form a structure of a replacement grid line on the top electrode/bottom electrode of the solar cell unit 100.

In some embodiments, the portions of the plurality of wires corresponding to the first diaphragm or the second diaphragm are formed in a structure that can replace the gate line. For example, the structure may be substantially similar to the main and sub gate line patterns.

In some embodiments, the portions of the plurality of wires corresponding to the first membrane or the second membrane may be replaced with other structures that facilitate current collection, such as an interdigitated electrode structure. Interdigital electrodes are electrodes having a periodic pattern in the face, such as fingers or combs, which are currently commonly used to create a capacitance associated with the electric field of the penetrable material sample and sensitive coating.

In some embodiments, as shown in fig. 4, there is a third portion of the middle of the plurality of wires 210 that is covered by the first membrane 221 and the second membrane 222 simultaneously. The length of the third portion is greater than the thickness of the battery cell. That is, the first membrane overlaps the second membrane at a third portion, and the length of the overlapping portion (third portion) is such that electrical contact between the plurality of wires 210 and the respective membrane layers of the battery at the edges is avoided. The length of the third portion is about 0.5-2mm. The third part is greatly enhanced in strength due to the overlapping of the first and second films, so that the third part is easier to take during laying, and the conducting wire 210 (generally a thin copper wire) at the third part can be protected after the assembly is shaped, so that the third part is not easy to break.

In addition, the third portion and other portions have relatively large thickness, so that the filler can isolate the side surface of the silicon wafer from the lead 210 during packaging of the assembly, and the hidden danger of short circuit of the battery is reduced.

Referring to fig. 6 and 7, the presence of the third portion facilitates bending of the plurality of wires 210 adjacent the two battery cells without breaking. The plurality of conductive lines 210 may be bent downward from the edge of the top electrode surface of the first battery cell to the bottom electrode surface of the adjacent second battery cell.

In other embodiments, there may be a region (corresponding to the bent portion between the first and second films in fig. 7) between the connection region of the first film 221 and the conductive wire 210 and the connection region of the second film 222 and the conductive wire 210, where the region is slightly larger than the diagonal line of the rectangle enclosed by the two adjacent solar cells 100 in the thickness direction in fig. 7, so that the connection member is crimped on the cell string, and when the first exposed portion of the first film 221 is crimped on the top voltage of the first cell 101 of the cell string, the second exposed portion of the second film 222 can be crimped on the bottom voltage region of the second cell 102 of the cell string. When the thickness of the membrane is thicker and the hardness is higher, the membrane is not arranged at the bending part, so that the connecting piece can be bent and extended from the top electrode of the first battery unit to the bottom electrode of the second battery unit.

The embodiment provides a connecting piece, and battery cells are interconnected through the connecting piece to form a battery string, so that the connecting piece is particularly suitable for battery cells sensitive to temperature such as perovskite batteries, and can solve the problems that in the conventional technology, the battery material performance, the warping of battery pieces, the reliability of components and the like are affected by adopting welding strips (or bonding conductive adhesive tapes or directly plating electrodes on substrate glass) and the like. The connecting piece provided by the invention can simultaneously realize a series connection process between the battery grid line and the battery, and solves the problems of high cost caused by silver paste, efficiency degradation, grid line breakage, poor electric conductivity and the like caused by the reaction of organic matters in the paste and the battery in the conventional technology.

In some embodiments, as shown in fig. 5, the wire 210 includes a metal core wire 211 and a wire coating 212 for blocking ion migration.

For perovskite cells or perovskite stacked cells, ions (particularly halogen ions) in the perovskite thin film migrate to the metal electrode and react with the electrode to form an interfacial layer, such as silver iodide, which is relatively insulating, greatly increasing the interfacial resistance and reducing the efficiency of the device. Meanwhile, the metal ions of the metal core wire 211 may migrate to the perovskite light absorption layer through the electrode layer (mostly transparent conductive layers such as ITO and IZO), and affect the stability and luminous efficiency of the perovskite light absorption layer.

The conductive wire coating 212 is at least distributed at the contact part of the metal wire core 211 and the electrode layer (top electrode/bottom electrode), so that the metal wire core 211 and the solar cell unit 100 can be isolated, ion migration of the metal wire core 211 to the solar cell unit 100 and migration of materials of each functional film layer of the solar cell unit 100 to the metal wire core 211 are blocked, the problem of efficiency reduction of the solar cell unit 100 caused by ion migration is solved, and the long-term stability of the solar cell unit 100 and the solar cell module thereof is prolonged. In addition, because the ends of the plurality of wires of the connecting piece are distributed in the electrode area corresponding to the battery unit, the battery unit interconnected by the connecting piece can replace a metal electrode and a grid line structure to collect current, the metal electrode and the grid line structure can be omitted, and the problem that the efficiency of the device is reduced due to the fact that the interface resistance is increased caused by the fact that ions of the battery absorbing layer material migrate and react with the metal electrode is solved. Meanwhile, the connecting piece 200 is electrically connected with the first electrode (for example, the upper electrode of the first battery unit) of the first battery unit and the second electrode (for example, the lower electrode of the second battery unit) of the second battery unit through the exposed parts at the two ends, so that the adjacent solar battery units 100 are electrically interconnected without additionally welding a conductive welding strip or a conductive adhesive tape.

The wire coating 212 may be uniformly distributed on the outer circumferential surface of the wire 210, or may be distributed only at a portion where the metal core 211 contacts the electrode layer. In some embodiments, the wire coating 212 is uniformly distributed on the outer circumferential surface of the wire 210.

In the present application, the metal wire core 211 may be any metal wire 210 in the prior art, such as copper wire, aluminum wire, and tin wire; it is preferably a copper wire because of its excellent conductivity, good mechanical properties and high cost performance. The metal core 211 may be a commercially available metal wire 210 having a plated surface, such as a nickel-plated metal wire 210 or a tin-plated metal wire 210.

The metal wire core is usually copper wire, and nickel plating or tin plating is used for protecting the copper wire. The wire coating in the application can also serve the purpose of protecting the metal wire core (such as copper wires), so that tin plating or tin plating layers can be omitted. If tin plating or tin plating is omitted, the wire with the same diameter (i.e. the same shading rate) of 70-80 nm is adopted, the diameter of the metal wire core can be slightly larger, and the resistance of the wire can be smaller.

In some embodiments, the material of the wire coating is a conductive ceramic. The meaning of ceramic material here means that the wire coating film layer is dense and can block ion migration. The wire coating is preferably doped or undoped metal nitride or carbide, and the film layer of the material is compact and can meet the requirement of blocking ion migration.

In some embodiments, the wire coating is preferably a doped or undoped transition metal nitride or carbide. Illustratively, the material of the wire coating 212 may be at least one of TiN, tiC, tiCN, tiSiN, alTiN, zrN, taN, hfN.

The transition metal nitride doped or undoped such as titanium nitride is a metal mesenchymal compound, has the properties of covalent compounds, ionic crystals and transition metals, and has the properties of high melting point, high hardness, high chemical stability, good heat conduction, electric conduction and the like. Therefore, forming a layer of wire coating 212 on the surface of the metal core 211 not only can block ion migration, but also can improve the mechanical properties and chemical stability of the wire 210 and prolong the service life thereof. In addition, the coating formed by the doped or undoped transition metal nitride such as titanium nitride can form smaller contact resistance with the transparent conductive electrode at the top of the battery, so that the conductive performance of the lead 210 is good.

In this application, the crystalline orientation of the doped or undoped transition metal nitride selected for the wire coating 212 is predominantly (111), but may also be predominantly (001) or (110).

In some embodiments, wire coating 212 is a microcrystalline film with predominantly (111) oriented crystals, which is more dense, oxidation resistant, and more resistant to ion migration. The crystal orientation is mainly (111) in this application, which means that the crystal orientation in the microcrystalline thin film is at most (111), and not that 100% of the crystal orientation in the microcrystalline thin film is (111).

Illustratively, the material of wire coating 212 is TiN, which forms an ideal TiN surface schematic with crystal orientations of (001), (110), (111) as shown in FIG. 3. However, tiN is difficult to form 100% of single crystal orientation in the actual preparation process, and the product is usually mainly crystalline with a certain crystal orientation and doped with a small amount of crystals with other crystal orientations, so that the crystal orientation is (111) in the application, which means that the main crystal orientation of the crystals in the material is (111), and not that the crystal orientation of the crystals in the material is 100% of the crystal orientation of the crystals in the material is (111). As can be seen from FIG. 3, there are two different specific Ti-/N-cut-off planes on the surface of the (111) -oriented TiN film. Since there is a rule of (111) Ti > (110) > (001) > (111) N for the adsorption capacity of O atoms. The oxidation degree depends on the difficulty of O atoms to be adsorbed on the surface to replace lattice N atoms, and in the process of O atoms to replace lattice N atoms, the energy required by the process is highest on the (111) surface, so that the oxidation resistance (111) > (110) > (001) of TiN with different crystal orientations is realized. In addition, the quality factor, dielectric constant, metallic, etc. properties of TiN of different crystal orientations also follow the law of (111) > (110) > (001), so in some embodiments, the wire coating 212 is a TiN film with a predominantly crystal orientation of (111).

In some embodiments, the wire coating 212 may be a single film layer or may be formed of multiple layers of film layers of the same or different materials. The wire coating 212 is preferably formed of a multi-layer film to further enhance the mechanical and optoelectronic properties of the wire coating 212 for good ion migration barrier.

In some embodiments, the wire coating 212 may be deposited on the surface of the metal wire core 211 by cathodic arc or sputtering. Optionally, the wire coating 212 is formed on the surface of the metal wire core 211 by magnetron sputtering to form a dense film layer, because the wire coating 212 on the surface of the metal wire core is preferably a film layer with better compactness to further improve the effect of the wire coating 212 in blocking ion migration, while the wire coating 212 formed by the magnetron sputtering technology has better compactness, higher binding force with the substrate (the metal wire core 211) and better uniformity, thus having better ion migration blocking effect.

The compactness and thickness of the wire coating in this embodiment are not particularly limited, and the implementation can be determined by a person skilled in the art according to test results or experience, based on the fact that the barrier effect on ion migration can meet the performance requirement of the battery. For example, the wire coating 212 may be a metal nitride film with a thickness of 0.1-5 μm formed by magnetron sputtering.

Alternatively, the magnetron sputtering technique may be any one of direct current magnetron sputtering, pulse magnetron sputtering, and high-energy pulse magnetron sputtering. In some embodiments, the magnetron sputtering technique may further improve the effective control of the film forming process and the distribution of the wire coating 212 by other means, for example, the magnetron sputtering technique and the pulse bias technique may be combined to improve the ionization rate and the inundation, so that the wire coating 212 obtained by the method has stronger bonding force and better uniformity with the metal wire core 211.

The magnetron sputtering technology is classified into direct current, direct current pulse, radio frequency and high energy pulse according to power supply, and reactive sputtering and non-reactive sputtering according to process gas and target material. Wherein, the film layer prepared by the high-energy pulse sputtering and the reactive magnetron sputtering processes is relatively denser. It is also possible to increase the compactness of the film by applying a negative bias to the substrate (in this case the wire).

When the magnetron sputtering technology is adopted to prepare the wire coating, one or more of the following modes for enhancing the compactness of the film can be adopted: direct current magnetron sputtering, direct current pulse magnetron sputtering, radio frequency magnetron sputtering and high-energy pulse magnetron sputtering; reactive magnetron sputtering; and, negatively biasing the metal core wire. Preferably, high energy pulses can be used to react magnetron sputtering while simultaneously negatively biasing the metal core.

Wire coatings can also be prepared using high energy pulsed magnetron sputtering (HiPIMS), with higher pulse peak power and lower pulse duty cycle to produce high sputter metal ionization rates, optimizing the performance of wire coating 212. Alternatively, the power of the high-energy pulse magnetron sputtering is 3-7kW/cm ² Duty cycle of<10%; the pulse width is 20-200 mu s, for example, the peak power of high-energy pulse magnetron sputtering can be 3kW/cm ² 、5kW/cm ² 、7kW/cm ² The method comprises the steps of carrying out a first treatment on the surface of the The duty cycle may be 0.5%, 1%, 2%, 3%, 4%, 5%, 8%; the pulse width may be 20 μs, 50 μs, 100 μs, 150 μs, 200 μs.

In some embodiments, a bonding layer, preferably titanium or chromium, may also be provided between the metal core and the wire coating. When the wire coating is titanium nitride, the bonding layer is preferably a titanium metal layer.

The thickness of the adhesive layer is 5-30 nm, preferably 10-20 nm.

In some embodiments, the metal wire core 211 corresponding to the third portion (corresponding to the bent portion in fig. 7) between the two battery cells, which is not covered by the separator, may not be covered with the wire coating 212 to facilitate bending. The material of the wire coating 212 is generally brittle and may break and crack when bent if covered with the wire coating 212.

In some embodiments, the wire 210 has a diameter of 30-80 μm and the wire coating 212 has a thickness of 0.1-5 μm. The distance between two adjacent wires is 1.5-3 mm. The diameter of the wire 210 should not be too high nor too low; the wires 210 having an excessively high diameter are easy to form a large shielding on the surface of the solar cell unit 100, reducing the efficiency of the solar cell unit 100; the wire 210 has a small diameter, a significant cost increase, and low mechanical strength, and is easily broken during lamination, which affects the performance of the solar cell module. The diameter of the wire 210 is preferably 50 to 70. Mu.m, more preferably 60 to 65. Mu.m. The thickness of the wire coating 212 is also selected to be suitable, not too high or too low, to reduce the influence of the wire coating 212 on the conductivity of the wire 210 and the shielding effect on the solar cell 100, and to achieve good ion migration blocking, oxidation resistance improvement, conductivity, and other properties at the same time.

In some embodiments, the cross-sectional shape of the wire 210 may be any shape, such as circular, non-standard circular (e.g., oval or flattened on both sides), triangular, rectangular, polygonal, kidney-shaped, etc. The cross-sectional shape of the wire 210 is preferably circular, non-standard circular such as oval or two-sided flattened circular or triangular, i.e.: the conductive wire 210 is preferably a circular conductive wire 210 or a triangular prism-shaped conductive wire 210, so that the light blocked by the conductive wire 210 can enter the solar cell 100 through secondary reflection of the conductive wire 210, thereby improving the light utilization rate.

In some embodiments, as shown in fig. 2, the plurality of wires includes a plurality of groups of wires arranged at intervals, each group of wires corresponds to a row of the battery cells, that is, each group of wires connects the corresponding two adjacent solar battery cells 100 located in a row in series. When a plurality of groups of wires are arranged on the connecting member, the connecting member can realize the same-row serial connection of more than two rows of solar battery units 100.

In some embodiments, the wires within each group may also be optimized for their shape, distribution, to better collect the current of the electrode area.

In some embodiments, referring to fig. 4 and 5, the first membrane 221 and the second membrane 222 respectively include a separation film 224 and an adhesive film 223 for adhering the conductive wires 210 to the separation film 224, so that the respective portions constituting the connection member 200 are fixed as a whole, thereby facilitating the one-time lamination of the connection member 200 and the solar cell unit 100 to form an assembly. In addition, the adhesive film 223 may be used to fix the lead 210 to the surface of the solar cell 100, so as to achieve reliable connection between the lead 210 and the solar cell 100.

In some embodiments, the isolation film 224 and the adhesive film 223 are polymer organic film layers formed by polymerizing polymer monomers or oligomers without organic solvents, so that the organic solvents are prevented from entering the solar cell unit 100, which affects the reliability and efficiency of the solar cell module, and the isolation film 224 and the adhesive film 223 are particularly not capable of containing organic solvents capable of separating out iodine ions, chlorine ions, fluorine ions, bromine ions and other ions, because halogen ions such as iodine ions, chlorine ions, fluorine ions, bromine ions and the like are easy to separate out and react with materials in the solar cell unit 100, which affects the reliability and electrical performance of the solar cell unit 100.

Similarly, in the prior art, if one or some of the layer structures of the solar cell unit 100 are prepared from a raw material containing an organic solvent such as iodide ion, chloride ion, fluoride ion, bromide ion, etc., the iodide ion, chloride ion, fluoride ion, bromide ion, etc. remain in the solar cell unit 100, and then in the use process, the iodide ion, chloride ion, fluoride ion, bromide ion, etc. are separated out and migrate to the surface of the solar cell unit 100, and react with the grid line or the solder strip, etc. chemically, thereby affecting the electrical performance and reliability of the solar cell module. In the application, the surface of the conductive wire 210 is provided with the conductive wire coating 212, which has stable chemical properties and compact film layer, and can prevent the iodine ions, chloride ions, fluoride ions, bromide ions and other ions from chemically reacting with the conductive wire 210, so as to improve the electrical properties and reliability of the solar cell module.

In some embodiments, the glass transition temperature of the adhesive film 223 is lower than the glass transition temperature of the release film 224.

The material of the adhesive film 223 may be selected from a polymer material having good adhesive property and a low glass transition temperature, such as polyolefin thermoplastic elastomer (POE), polyvinyl butyral Ding Quanzhi (PVB), ethylene-vinyl acetate copolymer (EVA), which is preferably a polymer material having a glass transition temperature of 140 ℃ or less, so that the wire is pressed on the film sheet by lamination or hot roller to form the connection member 200.

The material of the release film 224 may be selected from a polymer material having higher strength after curing, a certain flexibility, and a higher glass transition temperature than the adhesive film 2, such as a polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), and Polytetrafluoroethylene (PTFE). The polymer material with the glass transition temperature of more than 200 ℃ is preferable, so that the preparation of the connector 200 and the formation of the isolating film 224 layer with certain water blocking performance are facilitated, and the reliability of the solar cell module is improved. By pressing the wire onto the film by lamination or hot rollers, the adhesive film 2 is converted into a glassy state bonding fixing wire, and the separator 224 is still in the form of a solid film, so that the wire 210 can be prevented from being completely immersed in the adhesive film 2. The complete sinking of the conductive wire 210 into the adhesive film 2 affects the conductivity between the connection member and the battery cell, and thus the tandem connection performance of the adjacent battery cells.

Meanwhile, in the subsequent assembly process, the isolating film 224 can also prevent the sealant on the outer side (the side far away from the light absorbing layer) of the connecting piece from entering between the lead and the electrode of the battery unit (specifically, from entering the first and second exposed parts), and affecting the conductivity between the connecting piece and the battery unit.

In the present application, the material of the separator 224 is selected to be a polymer material having high light transmittance, so that the influence of the separator 224 on the light incidence and emission of the solar cell 100 is reduced as much as possible, and the light transmittance of the separator 224 is preferably not less than 95%. Also, the adhesive film 223 is preferably formed as a film layer having high light transmittance to reduce blocking. The adhesive film 223 preferably has a light transmittance of not less than 95%.

In some embodiments, the adhesive film 223 may be a sheet-shaped film layer, or may be disposed as a plurality of adhesive areas corresponding to the wires 210 one by one. The isolating film 224 is a sheet-shaped film layer to realize the integrity of the connecting piece 200 and achieve a certain water blocking effect, further improve the water oxygen protection and increase the stability of the battery.

At this time, the adhesive film 223 may include adhesive tapes, which are arranged in parallel or infinitely close to parallel arrays on the isolation film 224 in the same manner as the wires 210; at this time, gaps can exist between the adjacent adhesive tapes, so that higher overall light transmittance can be realized on the basis of slightly lower light transmittance material selection requirements.

In some embodiments, the plurality of wires are distributed in groups, and the adhesive tape corresponds to the distribution area of one group of wires, i.e., the adhesive film is distributed only in the corresponding area with the electrodes of the battery cells, so as to pre-fix the wires and bond the wires to the electrode areas in the subsequent process, and the adhesive tape is not present in other areas, such as the areas between two adjacent groups of wires.

In some embodiments, the thickness of the adhesive film 223 is less than the diameter of the wire 210 so that the wire 210 does not completely sink into the adhesive film 223 when the wire 210 is secured to the membrane, but there is a region that is partially uncovered by the adhesive film 223. In this way, the lead region not covered with the adhesive film 223 is used to connect the solar cell units 100, and the electrical interconnection of the solar cell units 100 is achieved.

Alternatively, the wire has a diameter of 30 to 80 μm, the adhesive film 223 has a thickness of 20 to 70 μm, and the wire diameter is ensured to be larger than the adhesive film thickness.

In some embodiments, the thickness of the release film 224 is 30-100 μm.

Optionally, the diameter of the wire is 30-80 μm.

Optionally, the spacing between two adjacent wires is 1.5-3 mm.

In some embodiments, the first exposed portion and the second exposed portion of the connector are square areas, and the battery cells are square. At this time, the connecting piece can be used for connecting adjacent battery cells in series in the transverse direction, and also can be used for connecting adjacent battery cells in series in the longitudinal direction, namely the same battery string realized by the connecting piece can be not limited to battery cells in the same row, and can be expanded to battery cells in adjacent rows. By selecting a suitable number of sets of connectors, a variety of battery string designs may be implemented.

As described above, the present application provides a connection member for interconnecting battery cells, which can constitute battery cells into a battery string in a module process, while the corresponding battery cells can also omit a grid line structure if the connection member of the present application is used. The leads of the connection member crimped to the electrode regions of the battery cells serve to collect current. Similarly, the corresponding battery cell may also omit the metal electrode. Further, the corresponding battery cell may also omit the transparent electrode, if necessary.

By adopting the connecting piece provided by the application, the preparation process of the battery unit can be simplified, the design of no main and auxiliary grid lines can be realized, the battery does not need to be subjected to screen printing to collect the grid lines of current, a single-junction battery or a laminated battery (double-junction or multi-junction battery) can be interconnected without a high-temperature welding process, the water blocking performance of the package of the component can be improved, the reliability of the component is improved, and the cost of the battery is reduced. In addition, the production line may not need equipment for forming electrodes, such as a plating equipment or screen printing.

Based on the above-mentioned connector 200, the present application further provides a solar cell module, which includes the connector according to any one of the above-mentioned embodiments, through which the cells are connected in series.

Exemplary, as shown in fig. 6: the first battery unit, the second battery unit, the third battery unit and the fourth battery unit are sequentially arranged, a part of the first connecting piece covers and is connected to the surface of the top electrode of the first battery unit, then the first connecting piece extends to the bottom electrode of the second battery unit from a gap between the first battery unit and the second battery unit, and covers and is connected to the surface of the bottom battery of the second battery unit, so that the first battery unit and the second battery unit are interconnected. Similarly, the top electrode of the second cell unit and the bottom electrode of the third cell unit are connected by the second connecting member, the top electrode of the third cell unit and the bottom electrode of the fourth cell unit are connected by the third connecting member, and the rest of the solar cell units can also be serially connected in sequence by the connecting member 200, and then led out from the solar cell units 100 at both ends and packaged to form a solar cell assembly.

In some embodiments, the electrodes of the battery units are preferably square, and correspondingly, the first exposed part and the second exposed part of the connecting piece are square areas, at this time, the connecting piece can be used for connecting adjacent battery units in series in the transverse direction or in the longitudinal direction, that is, the same battery string realized by the connecting piece of the present application can be not limited to the battery units in the same row, but can be expanded to the battery units in adjacent rows. By selecting a suitable number of sets of connectors, a variety of battery string designs may be implemented.

Based on the same inventive concept, the present application also provides another solar cell module that does not use a prefabricated connection. The assembly comprises: at least one battery string including at least two battery cells 101 and 102. As shown in fig. 6 and 7, the two battery units 101 and 102 are connected in series through a plurality of parallel wires 210, wherein a first end of the plurality of wires 210 is crimped to a first electrode (e.g., a top electrode of 101 in fig. 7) of the first battery unit 101, and a second end of the plurality of wires 210 is crimped to a second electrode (e.g., a bottom electrode of 102 in fig. 7) of the second battery unit 102.

The assembly further includes a first membrane disposed above the battery string and a second membrane disposed below the battery string; the battery string, the first membrane and the second membrane are bonded to each other.

In some embodiments, the wire includes a metal core, and a wire coating for blocking ion migration; the wire coating is distributed at least at the contact part of the metal wire core and the electrode layer.

In some embodiments, the material of the wire coating is a conductive ceramic. Preferably, the material of the wire coating is at least one of TiN, tiC, tiCN, tiSiN, alTiN, zrN, taN, hfN.

Preferably, the wire coating is formed on the surface of the metal wire core in a manner of forming a compact film through magnetron sputtering.

Preferably, in some embodiments, the wire coating is a microcrystalline film having a predominant crystal orientation of (111).

In some embodiments, the wire coating has a thickness of 0.01 to 5 μm. Preferably, the thickness of the wire coating is 100 to 200 nanometers.

Preferably, in some embodiments, the middle portions of the plurality of wires are at a third portion that is not covered by the first membrane and is also not covered by the second membrane, and the length of the third portion corresponds to the pitch of the battery cells. The third part is mainly determined by the distance between the first battery unit and the second battery unit which are interconnected by the connecting piece, meanwhile, the thickness of the battery unit also affects the length of the third part, and the thicker the battery unit is, the longer the third part is. The length of the third portion is about 0.5-2mm.

The third part is covered by the first membrane and the second membrane (comprising the isolating membrane and the adhesive membrane) at the same time, so that the strength is greatly enhanced, and the third part is easier to take during laying. After the assembly is shaped, the sealant enters a gap of the battery unit to protect a lead of the third part, and the lead is not easy to break; the sealant can isolate the side face of the silicon wafer from the lead, so that the hidden danger of short circuit of the battery is reduced. Preferably, in some embodiments, the plurality of wires are distributed in groups, each group of wires corresponding to a row of battery cells.

Preferably, in some embodiments, the wire width of the wire is 30-140 μm, preferably 70-140 μm. For the wiring line width of 75 to 85 μm, preferably 80 μm in the crystalline silicon perovskite laminated cell module connector.

Preferably, in some embodiments, the spacing between adjacent two wires is 1.5-3 mm.

When the cross section of the wire is circular, the line width of the wire refers to the diameter of the wire, i.e., the wire diameter is 30 to 80 μm. When the cross section of the lead is another shape such as an ellipse or a triangle, the line width of the lead refers to the width of the lead projected to the surface of the battery cell.

In some embodiments, the spacing between the adjacent wires 210 is 1.5-3 mm, and the spacing between the wires 210 is not too high or too low, so as to avoid light shielding caused by too dense wires 210 and avoid the problems of poor current collecting effect, high loss, reduced output power, etc. caused by too few wires 210.

In some embodiments, the first membrane and the second membrane each comprise a release film and an adhesive film, the plurality of wires being partially embedded in the adhesive film. The adhesive film has a glass transition temperature lower than that of the separator film. The material of the adhesive film can be at least one selected from polyolefin thermoplastic elastomer, polyvinyl alcohol Ding Quanzhi and ethylene-vinyl acetate copolymer; the material of the isolation film can be at least one selected from the group consisting of a polyethylene terephthalate, a polyvinylidene fluoride and a polytetrafluoroethylene.

The thickness of the adhesive film is smaller than the diameter of the wire. If the wire cross-section is of other shape such as triangular, oval, the diameter of the wire as described herein refers to the dimension of the wire in a direction perpendicular to the adhesive film, which is smaller than the thickness of the adhesive film, to ensure that the wire is partially embedded in the adhesive film when the wire is secured to the separator film by lamination or other processes, forming exposed portions that are electrically connected to the electrodes.

The thickness of the adhesive film is 20-70 mu m; the thickness of the isolating film is 1-100 μm. Preferably, the thickness of the release film is preferably 10-80 μm, depending on the current process conditions.

In some embodiments, an encapsulation film is further provided on a side of the release film remote from the adhesive film; the battery string, the first membrane and the second membrane are bonded together by a lamination process at the time of packaging.

In the solar cell module provided by the application, the surface of the solar cell unit 100 is not provided with the grid lines such as the main grid line and the auxiliary grid line formed by silver paste, the wires 210 of the wires can replace the grid lines on the surface of the solar cell unit 100, and the effect of current collection can be achieved after the solar cell unit 100 is interconnected.

In some embodiments, the cross-sectional shape of the wire 210 may be any shape, such as circular, triangular, rectangular, polygonal, kidney-shaped, etc., preferably circular, triangular. When the cross section is circular or triangular, the shielded light rays can be reflected and collected secondarily in the assembly by the lead wires, so that the light ray absorptivity can be improved. When the cross-sectional shape of the conductive line 210 is a triangle, that is, when the conductive line 210 is a triangular prism, one of the facets is connected to the top/bottom electrodes of the solar cell 100.

The solar cell in the application can be any one of a silicon solar cell, a multi-element compound thin film solar cell, a polymer multilayer modified electrode type solar cell, a nanocrystalline solar cell, an organic solar cell and a plastic solar cell, and the structure of the solar cell can be a formal structure or a trans structure or any other configuration in the prior art. The solar cell 100 is illustratively a perovskite solar cell including a bottom electrode, a hole transporting layer, a perovskite light absorbing layer, an electron transporting layer, and a top electrode, which are stacked in this order. Any bottom electrode material suitable for perovskite solar cells, such as Ag, au, cu, C, al, ITO, FTO, IWO, ICO, IZO, AZO, or other bottom electrode materials, which are not limited in the present application, may be selected as the bottom electrode material, and the bottom electrode may be omitted. The hole transport layer material may be any suitable hole transport layer material for perovskite solar cells, such as PTAA, PEDOT: PSS, spiro-OMeTAD, poly-TPD, cuSCN, cu2O, cuI, niO _x 、P3HT、MoOx、V ₂ O ₅ Any one of 2PACz, 4PACz, meO-4PACz, spiro-TTB, F4-TCNQ, F6-TCNNQ, m-MTDATA, meO-2PACz and TAPC can also be other hole transport layer materials, and is not limited in the application; the material of the perovskite light absorbing layer may be any perovskite light absorbing layer material suitable for perovskite solar cells, such as FAPbI ₃ ，MAPbI ₃ ，FACsPbI ₃ The isochemical structural formula can be ABX ₃ Other perovskite light absorbing layer materials, or mixed cationic perovskite materials, mixed anionic perovskite materials, are not limited in this application. The material of the perovskite light absorbing layer may be selected, for example, from FACsPbIBrCl, FAMACsPbIBrCl, FACsDMAPbIBrCl, csDMAPbIBrCl, FACsPbIBr, FAMACsPbSnIbIBr, FACsDMAPbIBr and CsDMAPbIBr.

The material of the electron transport layer may be any material of electron transport layer materials suitable for perovskite solar cells,such as PCBM, tiO ₂ 、ZnO、SnO ₂ At least one of H-PDI, F-PDI, C60 and ICBA can also be other electron transport layer materials, and is not limited in the application; the top electrode material may be any top electrode material suitable for perovskite solar cells, such as at least one of ITO, FTO, IWO, ICO, IZO, AZO, or other top electrode materials, which are not limited in this application.

Further, the perovskite solar cell 100 may further include other functional layers, such as an electron blocking layer, a hole blocking layer; illustratively, when the perovskite solar cell 100 is provided with a hole-transporting barrier layer, the hole-blocking layer is disposed between the electron-transporting layer and the top electrode, and the material of the hole-blocking layer may be any hole-blocking layer material that is suitable for perovskite solar cells, such as BCP, snO ₂ Other hole blocking layer materials, or unimpeded barrier layer materials, are also possible and are not limited in this application.

The thickness of each layer structure in the solar cell unit 100 can be adjusted according to the need, and still taking the perovskite solar cell unit 100 as an example, the thickness of the bottom electrode of the perovskite solar cell unit can be 80-150 nm; the thickness of the hole transport layer may be 5 to 20nm; the thickness of the perovskite light absorption layer can be 600-800 nm; the thickness of the electron transport layer may be 20 to 30nm; the hole blocking layer may have a thickness of 6 to 8nm and the top electrode may have a thickness of 80 to 300nm.

The present embodiment also provides another connector for electrically connecting the battery cells of the battery string with the bus bars. Specifically, as shown in fig. 8, an exemplary connector is different from the above-described connector in that the first exposed portion 220 (or the second exposed portion) of the present embodiment includes: a body portion 225 for crimping onto the first electrode (or the second electrode), and an extension portion 226 for electrical connection with the bus bar. The body portion 225 is for crimping onto the electrode of the battery cell that is the beginning or end of the battery string, and the extension portion 226 is for crimping onto the bus bar. The body portion 225 and the extension portion 226 are each formed by partially embedding the lead 210 into the first membrane 221.

In other embodiments, the body portion 225 and the extension portion 226 may also be located on the second membrane 222, i.e., the second exposed portion formed by partially embedding the wire 210 into the second membrane 222 includes the body portion 225 and the extension portion 226.

Specifically, another exemplary connector is shown in fig. 9, and further includes: a third membrane 227 provided at an edge of the second membrane 222 (or the first membrane 221); the plurality of wires 210 extend to the third diaphragm 227 and are partially embedded in the third diaphragm 227, and exposed extension portions 226 for corresponding and electrically connecting with the bus bars are formed at regions corresponding to the third diaphragm 227. The extension 226 is used to press-fit over the bus bar to electrically connect the battery string to the bus bar. The extension 226 is opposite the second exposed portion and the projections do not overlap.

Specifically, another exemplary connector is shown in fig. 10, the connector 200 for connecting a solar cell string with a bus bar, the connector comprising: a plurality of wires 210 arranged in parallel; and a membrane 228 for fixing the plurality of wires, each of the plurality of wires being partially embedded in the membrane 228 to form a first exposed portion 220, the first exposed portion 220 including a body portion 225 for corresponding and electrically connecting with an electrode of a third battery cell, which is a starting or ending battery cell of the solar cell string, and an exposed extension portion 226 for electrically connecting with a bus bar.

Specifically, another exemplary connector is shown in fig. 11, the connector 200 for connecting a solar cell string with a bus bar, the connector comprising: a plurality of wires 210 arranged in parallel; and a first membrane 221 and a third membrane 227 for fixing the plurality of wires, wherein first ends of the plurality of wires are partially embedded in the first membrane to form a first exposed portion 220, second ends of the plurality of wires are partially embedded in the third membrane 227 to form an exposed extension portion (not shown) for corresponding to and electrically connecting with an electrode of a third battery cell, which is a battery cell at the beginning or end of a solar cell string, and the extension portion is for electrically connecting with a bus bar.

It should be noted that the technical features of the present application may be arbitrarily combined into the connecting piece of the present application under the precondition of no conflict, and for brevity of description, the description is omitted here.

The connecting piece provided by the implementation can realize that the battery units are connected into a string, and the battery units at the head and the tail of the battery string can be connected to the bus bar. The battery unit is connected through the connecting piece by adopting lamination or hot roller technology, and then the assembly is packaged; the battery cell can be connected with the connecting piece through the lamination process while packaging the assembly, so that the series connection and packaging of the battery cell are completed in one step.

The application also provides a preparation method of the connector 200, which comprises the following steps:

arranging a plurality of wires in parallel; the first membrane and the second membrane are respectively placed on the upper side and the lower side of the plurality of wires, and the first membrane and the second membrane are respectively positioned at two ends of the wires; pressing the first membrane, the plurality of parallel wires and the second membrane together by using a hot pressing process to form a connecting piece; wherein, the first ends of the plurality of wires are partially embedded into the first membrane to form a first exposed part which corresponds to and is electrically connected with the first electrode of the first battery unit; the second ends of the plurality of wires are partially embedded in the second membrane to form a second exposed portion corresponding to and electrically connected with the second electrode of the second battery cell.

The hot pressing process refers to partially embedding the plurality of wires into the first film sheet by applying pressure at a certain temperature, and is exemplified by lamination or hot rolling technology.

The first membrane 221 and the second membrane 222 are made of the same material and structure, and the material which can be embedded into the wires through a hot pressing process is selected. Illustratively, the first membrane 221 and the second membrane 222 each include a separation film 224 and an adhesive film 223, and the temperature of the hot pressing process is selected to be lower than the glass transition temperature of the separation film 224 and higher than the glass transition temperature of the adhesive film 223, so that the adhesive film 223 is softened during the hot pressing process, and the wires 210 are conveniently partially embedded in the adhesive film 223, so as to achieve the adhesive fixation of the wires 210; meanwhile, the glass transition temperature of the isolating film 224 is not reached, so that the isolating film 224 is not softened, the stress bearing in the hot pressing process can be provided, one side of the isolating film 224 of the obtained connecting piece 200 is flat, the depth of the wires 210 sinking into the adhesive film can be limited, and the wires 210 are prevented from being completely wrapped by the adhesive film or the component packaging adhesive.

In some embodiments, the thermal compression process secures the leads 210 to the first and second diaphragms, including:

the first end of the wire 210 is pressed against the first membrane 221 and the second end of the wire 210 is pressed against the second membrane 222 using a heated roller at 20-250 c.

The separation film 224 and the adhesive film 223 may be separately prepared, and then the films (first film 221/second film 222) are formed by lamination technology, and then bonded with the wires 210 by thermal compression technology to form the connection member 200. The wire 210 may be fixed to the first membrane 221/the second membrane 222 by a hot pressing process by preparing the separation film 224 and then directly coating the separation film 224 to form the adhesive film 223.

In some embodiments, prior to the thermo-compression, further comprising forming the wire for thermo-compression by: and forming a wire coating for blocking ion migration on the surface of the metal wire core by utilizing a magnetron sputtering technology to obtain the wire with the wire coating on the surface.

In some embodiments, the magnetron sputtering technique is any one of direct current magnetron sputtering, pulsed magnetron sputtering, radio frequency magnetron sputtering, reactive magnetron sputtering. Preferably, the magnetron sputtering technique is pulsed magnetron sputtering, more preferably high energy pulsed magnetron sputtering, with higher pulse peak power and lower pulse duty cycle to produce high sputter metal ionization rates, optimizing the performance of the wire coating 212. The average pulse magnetron sputtering power of the high-energy pulse is 3-7kW/cm ² Duty cycle of<10%; the pulse width is 20-200 mu s.

The film prepared by high-energy pulse sputtering and reactive magnetron sputtering is compact.

The wire coating can be prepared by adopting one or more of the following modes for enhancing the compactness of the film: direct current magnetron sputtering, direct current pulse magnetron sputtering, radio frequency magnetron sputtering and high-energy pulse magnetron sputtering; reactive magnetron sputtering; and, negatively biasing the metal core wire.

In addition, the present application also provides a method for manufacturing a solar cell module, in which the connection piece 200 is used to connect the top electrode and the bottom electrode of two adjacent solar cell units 100 respectively, and then the connection piece 200 is connected with the solar cell units 100 by using a lamination technology, so as to form the solar cell module.

In some embodiments, the assembly preparation method comprises:

placing the first battery cell 101 and the connecting member 200 such that the first exposed portion of the connecting member 200 corresponds to the first electrode of the first battery cell 101;

placing the second battery unit 102, and enabling the second electrode of the second battery unit 102 to correspond to the second exposed part of the connecting piece 200;

crimping a first exposed portion of the connector 200 onto a first electrode of the first battery cell 101 using a lamination technique, a wire of the first exposed portion collecting current of the first electrode; while a second exposed portion of the connector 200 is crimped onto a second electrode of the second cell 102, the wire of the second exposed portion collecting the current of the second electrode.

In this case, the temperature in the lamination technique used is preferably 80 to 120 ℃.

In some embodiments, the present application also provides a method of making another component, comprising:

fixing first ends of the plurality of wires 210 to a first electrode of the first battery cell 101 by a dispensing process, and fixing second ends of the plurality of wires 210 to a second electrode of the second battery cell 102 to form a battery string including at least two battery cells;

placing a first membrane 221 over the plurality of cell strings and a second membrane 222 under the plurality of cell strings;

the battery string, the first membrane 221, and the second membrane 222 are connected together using a lamination technique.

In some embodiments, the solar cells may be connected in strings using lamination techniques simultaneously while packaging the solar module. The connection of the connection member 200 to the solar cell unit 100 using the lamination technique may be performed before or during the encapsulation of the module, that is: the connection member 200 may be connected to the solar cell unit 100 using a lamination technique before the solar cell module is packaged, and then the solar cell module is packaged. Alternatively, the connection members 200 may be placed on the adjacent two solar cells 100, and then the packaging film layer is placed thereon, and the connection members 200, the packaging film layer and the solar cells 100 are connected by lamination technology, so that the interconnection of the cells is completed while the assembly is packaged.

In the solar cell module provided by the application, the surface of the solar cell unit 100 is not provided with the grid lines such as the main grid line and the auxiliary grid line formed by silver paste, and the welding strip for connecting the solar cell unit 100 is not needed, so that the solar cell unit 100 is connected to form the solar cell module, high-temperature welding is not involved, the screen printing process is not involved, the warping phenomenon, hidden cracking and the influence of film degradation caused by the high-temperature process on the cell performance due to the high-temperature welding, the screen printing process and other higher-temperature processing of the solar cell unit 100 are avoided, the reliability of the solar cell module is improved, and the development of the solar cell industrialization process is promoted.

The above-described perovskite solar cell, perovskite light absorbing layer and method of manufacturing the same of the present application will be described below in conjunction with specific examples, which should be understood by those skilled in the art to be merely helpful in understanding the present invention and should not be construed as limiting the present application in detail.

Example 1

The present embodiment provides a perovskite crystalline silicon stacked solar cell module including a plurality of cell strings, each cell string including 6 interconnected solar cell units 100. The 6 solar battery units 100 are connected through the connecting piece 200 Are connected in series, and the solar cell 100 has the structure of ITO/SnO _x C60/perovskite/PTAA/ITO/n-Si: H (n)/n-Si: H (i)/C-Si (n)/n-Si: H (i)/n-Si: H (p)/ITO. The connector 200 comprises a copper core wire 210, an adhesive film 223 and a separation film 224, wherein the diameter of the copper core wire 210 is 70um, the material of the wire coating 212 is TiN, and the thickness of the wire coating is 300nm; the adhesive film 223 is made of POE with thickness of 60um, and the isolating film 224 is made of PET with thickness of 50um and light transmittance of 97%; the spacing between adjacent wires 210 is 2mm.

One exemplary method of making the copper core wire 210 is: the copper wire is used as a wire core, a magnetron sputtering coating machine is adopted to form a wire coating 212 on the surface of the copper wire, the process gas is argon/nitrogen, the power is 5kW, and the target material is a titanium target.

Then, the adhesive film 223 and the isolating film 224 are connected by lamination technology, and the prepared copper core wire 210 is adhered and solidified on the film layer to obtain the connecting piece.

The prepared first exposed portion of the connection member 200 is covered on the top electrode of one of the solar cell units 100, and the first exposed portion is covered on the bottom electrode of the other solar cell unit 100 to connect the two cell units. Similarly, a plurality of connectors may be placed to achieve a predetermined battery cell connection scheme. And then carrying out lamination process under the following process parameters: the temperature is 120 ℃, the pressure is 60kPa, and the time is 20 minutes; after lamination, a solar cell module sample a was obtained using a double sided POE encapsulant film and double sided glass encapsulation.

When the sizes of the components are different, the wire diameters of the corresponding connecting piece wires can be adjusted according to the following schemes: when the size of the assembly is 210mm or 210mm, the wire diameter of the wire is 120-140 mu m; the wire diameter is 80-100 μm when the assembly size is 210mm by 105 mm.

Example 2

In this embodiment, the wire coating 212 on the wire 210 is formed by a high-energy pulse magnetron sputtering process, and specific process parameters thereof are: peak power 5kW, duty cycle 1%; the pulse width is 10us; the remaining steps were the same as in example 1, to obtain a solar cell module sample B.

Example 3

In this embodiment, a tin-plated copper wire is used as the metal wire core 211 in the conductive wire 210, the conductive wire coating 212 on the conductive wire 210 is a ZrN layer formed by a pulse magnetron sputtering process, the material of the adhesive film 223 is EVA, the material of the isolation film 224 is PEN, and the rest steps are the same as those in embodiment 1, so as to obtain a solar cell module sample C.

Example 4

In this example, the solar cell unit was a heterojunction cell having the structure of ITO/n-Si: H (n)/n-Si: H (i)/c-Si (n)/n-Si: H (i)/n-Si: H (p)/ITO, and the remaining steps were the same as in example 1, to obtain a solar cell module sample D.

In some embodiments, the wires in the connector are copper wires with titanium nitride coating, and titanium nitride can be plated on the surfaces of the copper wires as the wire coating by using magnetron sputtering or cathodic arc.

The cathodic arc deposition system is used for plating a layer of titanium nitride on the surface of a cutter and the like as a hard coating, and the process is mature and is not described in detail herein. In the application, the copper wire plated with the titanium nitride film layer is used for interconnecting the solar cells, so that the reduction of the efficiency of the device caused by the reaction between halogen ions in the light absorption layer material such as a perovskite film and the metal electrode due to migration of the halogen ions to the metal electrode can be avoided.

In another embodiment, before the titanium nitride coating is plated, a titanium metal layer is firstly plated on the copper wire to serve as a bonding layer of the titanium nitride coating, so that the adhesive force of the titanium nitride coating is improved, and the compactness of the titanium nitride coating is improved. The titanium nitride coating is selected as the peripheral surface coating of the lead, the titanium metal layer is selected as the bonding layer of the titanium nitride coating, the titanium nitride coating is easy to realize on a production line, and meanwhile, the target material can be prevented from being polluted.

The connector may extend outside the package layer of the component, forming an external interface to the component. Titanium nitride and titanium have good corrosion resistance, and are not influenced by atmosphere and seawater.

As shown in fig. 12, the contact resistance (refer to the slope of the test simulation line in fig. 12) of the copper wire with titanium nitride coating and the ITO (transparent conductive layer commonly used in solar cells) surface was slightly smaller than that of the conventional tin Bao Tongsi. However, copper wires with titanium nitride coatings can avoid the problem of degradation of cell efficiency due to interdiffusion of the metal electrode with the perovskite light absorbing layer (or other light absorbing layer material, or other adjacent or contact layer) due to the permeation resistance of the titanium nitride coating.

The technical features of the present application may be used in any combination without conflict. In order to facilitate understanding of technical advantages of the technical scheme of the present invention, some related technologies are briefly described below, and effect comparison is performed with the scheme of the present application.

For solar cells, a welding belt is generally adopted to weld at a certain high temperature to form a cell string, and the welding belt is easy to cause the phenomena of warping and hidden cracking of the cell, so that the reliability of the assembly is influenced, the high temperature generated in the welding process can influence the performance of the cell, particularly for perovskite cells, the temperature sensitivity is very high, and the perovskite cell layer can be damaged by a high-temperature process in the welding process, so that the performance of the cell is influenced.

Currently, crystalline silicon batteries generally use silver paste to prepare a main grid and an auxiliary grid for converging and collecting current. For a crystalline silicon perovskite laminated cell, organic matters in the silver paste react with the perovskite cell to cause degradation of cell efficiency; meanwhile, the grid lines are also easy to break, poor in conductivity and the like, and the reliability of the battery is affected.

At present, for perovskite batteries, no matter single junction batteries or stacked batteries (double-junction or multi-junction batteries), the current common electrode extraction mode is conductive adhesive tape bonding, or a mode of directly extracting metal electrodes on substrate glass and welding with low-temperature slurry, but the modes have the problems of influencing the reliability of the batteries, such as: and the problems of precipitation of conductive peptizing agent, adhesion reliability, electrode oxidation resistance, component reliability and the like restrict the industrialization development progress of the perovskite battery.

The mode of low-temperature slurry welding is as follows: for the electrode extraction and battery string connection mode of low-temperature slurry welding, silver slurry and a welding belt with very low welding temperature are needed. The low-temperature silver paste basically depends on import, the price is relatively high, and the low-temperature welding strip has relatively high cost due to the need of adding elements such as In which are melted at low temperature;

the process temperature of low-temperature silver paste and welding strips adopted by the heterojunction battery at present is generally lower than 250 ℃, and the high process temperature has great damage to perovskite materials, damages the perovskite battery materials and influences the battery performance;

the low-temperature welding has low welding tension because special elements (such as In and other metal elements) are doped In the silver paste and the welding strip; in addition, the low-temperature silver paste is based on the process temperature below 250 ℃, the silver powder sintering process is not needed, and the silver powder and the silver and the base material are bonded by means of organic resin. Unlike conventional crystalline silicon battery slurry, which is sintered at high temperature, silver powder is connected to each other by means of surface melting, and glass phase melts silver to a certain extent and etches a silicon substrate to form reliable bonding and ohmic contact, so that welding tension is lower. Lower solder pull forces can cause problems with the assembly during reliability testing.

The main grid and the auxiliary grid of the low-temperature slurry screen printing have relatively poor conductivity due to the lack of a high-temperature sintering process.

The conductive adhesive tape is adhered in the following manner: because the binding force of the perovskite battery electrode is lower, the electrode is easy to fall off in the bonding process of the conductive adhesive tape, and the battery is invalid. Because the bonding surface of the conductive adhesive tape is conductive adhesive, the conductive adhesive may contain organic solvent, and the solvent precipitation can have a certain influence on the perovskite layer, thereby influencing the battery efficiency. The conductive adhesive tape adhesion has a certain risk of contact reliability because the adhesion is performed only by the conductive adhesive. Because the outer layer of the conductive adhesive tape is copper generally, the problem of poor oxidation resistance also exists;

the mode of the metal electrode is plated on the substrate glass: because the electrode is directly plated on the substrate glass, the electrode has the problem of oxidation resistance in the later use process; during use of the assembly, water vapor risks entering the interior of the assembly along the electrodes, affecting the reliability of the assembly.

The connecting piece or the novel connecting scheme provided by the application can separate the process for preparing the wire coating by sputtering, which can possibly influence the perovskite battery layer, so that the battery units can be interconnected only through low-temperature lamination or a hot roller, the battery performance is not influenced, the connection is reliable, and the phenomena of easy warping and hidden cracking of the battery caused by welding of a welding strip are avoided.

The connecting piece or the novel connecting scheme can omit a grid line process, and reliable connection is realized without silver paste, so that the problem that organic matters in silver paste react with a perovskite battery to cause degradation of battery efficiency is avoided. In addition, by arranging the wire coating, the problem of interface resistance increase caused by the reaction of the migration ions in the perovskite and the metal electrode can be further avoided.

In summary, the connector scheme provided by the application can replace the conventional solder strip interconnection process. The end part of the connecting piece can replace a grid line structure to collect electrode current (a main grid line preparation process and an auxiliary grid line preparation process can be omitted when the battery units are prepared), and the whole connecting piece can replace a welding strip to realize interconnection among the battery units, so that the battery preparation process and the assembly process are simplified, and the problems of high cost of low-temperature silver paste, and relatively poor conductivity of the main grid and the auxiliary grid of low-temperature paste screen printing due to lack of a high-temperature sintering process in the prior art are solved. The connecting piece or the novel connecting scheme provided by the application can avoid the defects of the existing connecting scheme.

The present invention is not limited to the above embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A connector for connecting at least two solar cells in series, comprising:

a plurality of wires arranged in parallel;

first ends of the plurality of wires are partially embedded into the first membrane, and a first exposed part which corresponds to and is electrically connected with the first electrode of the first battery unit is formed in a region corresponding to the first membrane; the second ends of the plurality of wires are partially embedded in the second membrane, and a second exposed part which corresponds to and is electrically connected with the second electrode of the second battery unit is formed in a region corresponding to the second membrane.

2. The connector of claim 1, wherein the first exposed portion or the second exposed portion comprises: a body portion for crimping on the first electrode or the second electrode, and an extension portion for electrically connecting with a bus bar; or,

the connector further comprises: the third diaphragm is arranged at the edge of the first diaphragm or the second diaphragm; the plurality of wires extend to and are partially embedded in the third membrane, and exposed extension portions for corresponding and electrically connecting with the bus bars are formed at regions corresponding to the third membrane.

3. The connector of claim 1 or 2, wherein the wire comprises a metal core and a wire coating for blocking ion migration; the wire coating is at least distributed at the part of the metal wire core, which is contacted with the electrode layer of the solar cell unit.

4. A connector according to claim 3, wherein the wire coating is distributed on the outer peripheral surface of the metal wire core.

5. A connector according to claim 3, wherein the wire coating is of a conductive ceramic.

6. A connector according to claim 3, wherein the wire coating is of any one of TiN, tiC, tiCN, tiSiN, alTiN, zrN, taN, hfN materials.

7. A connector according to claim 3, wherein the wire coating is a microcrystalline film, and the microcrystalline film is a microcrystalline film having a crystal orientation of (111).

8. A connector according to claim 3, wherein the wire coating has a thickness of 0.01 to 5 μm.

9. The connector of claim 1, wherein a third portion is present in the middle of the plurality of wires, the third portion corresponding to a spacing of the first and second battery cells, the third portion being simultaneously covered by the first and second diaphragms.

10. The connector of claim 1, wherein the plurality of wires are distributed in groups, each group of wires corresponding to a row of battery cells.

11. The connector of claim 1, wherein the wire has a line width of 30-140 μm; and/or the interval between two adjacent wires is 2-4 mm.

12. The connector of claim 1, wherein the wire has a line width of 75-85 μm.

13. The connector of claim 1, wherein the wire has a circular or triangular cross-sectional shape.

14. The connector of any one of claims 1, 2, 4-13, wherein the first and second membranes each comprise a release film and an adhesive film for adhering the wire to the release film; the adhesive film has a glass transition temperature lower than that of the separator film.

15. The connector of claim 14, wherein the adhesive film has a thickness less than a diameter of the wire.

16. A connector for connecting a solar cell string with a bus bar, comprising:

a plurality of wires arranged in parallel;

The membrane is used for fixing the plurality of wires, the plurality of wires are partially embedded in the membrane to form an exposed part, the exposed part comprises a main body part used for corresponding and electrically connecting with electrodes of a third battery unit, and an extension part used for electrically connecting with a bus bar, and the third battery unit is a battery unit at the beginning or the end of the solar battery string.

17. A solar module comprising the connector of any one of claims 1-16; alternatively, the solar cell module includes:

18. The solar cell module of claim 17 wherein the wire comprises a metal wire core and a wire coating for blocking ion migration; the wire coating is at least distributed at the contact part of the metal wire core and the electrode layer.

19. The solar cell assembly of claim 17, wherein the first and second membranes each comprise a separator and an adhesive film, the plurality of wires being partially embedded in the adhesive film; the adhesive film has a glass transition temperature lower than that of the separator film.

20. The solar cell module of claim 19, wherein an encapsulation film is further provided on a side of the separator film remote from the adhesive film; the battery string, the first membrane and the second membrane are bonded together by a lamination process at the time of packaging.