KR101282939B1

KR101282939B1 - Solar cell module

Info

Publication number: KR101282939B1
Application number: KR1020110098998A
Authority: KR
Inventors: 조진현; 최정훈; 지광선
Original assignee: 엘지전자 주식회사
Priority date: 2011-09-29
Filing date: 2011-09-29
Publication date: 2013-07-08
Also published as: KR20130034869A

Abstract

The present invention relates to a solar cell module, the solar cell module according to an embodiment of the present invention is located on the first corner side of the back of the substrate, the current collector for the first electrode extending in the first direction, and A plurality of back-junction solar cells positioned at two corners and each including a current collector for a second electrode extending in a first direction; A conductive adhesive film contacting at least one of a second electrode current collector of one solar cell and a first electrode current collector of another solar cell among two solar cells adjacent to each other; An interconnector in contact with the conductive adhesive film and electrically connecting two solar cells adjacent to each other; A front seal and a back seal to protect the solar cells; A transparent member disposed above the front seal member toward the front surface of the substrate; And a back sheet disposed below the back seal toward the back of the substrate.

Description

Solar cell module {SOLAR CELL MODULE}

The present invention relates to a solar cell module.

With the recent prediction of the depletion of existing energy resources such as oil and coal, the interest in renewable energy to replace them is increasing, and solar cells that produce electric energy from solar energy are attracting attention. Background Art A back junction type solar cell has been developed that increases the light receiving area by forming electrodes on the rear surface of the substrate, that is, the surface where no light is incident.

The back junction solar cell is used as a solar cell module that is waterproof in the form of a panel after several are connected in series or in parallel to obtain a desired output.

The technical problem to be achieved by the present invention is to provide a solar cell module with improved reliability and durability.

According to an embodiment of the present invention, a solar cell module includes a substrate, a current collector for a first electrode extending in a first direction and positioned in a first corner of a rear surface of the substrate, and a second corner of a rear surface of a substrate in a first direction. A plurality of back junction solar cells each including an extended current collector for the second electrode; A conductive adhesive film contacting at least one of a second electrode current collector of one solar cell and a first electrode current collector of another solar cell among two solar cells adjacent to each other; An interconnector in contact with the conductive adhesive film and electrically connecting two solar cells adjacent to each other; A front seal and a back seal to protect the solar cells; A transparent member disposed above the front seal member toward the front surface of the substrate; And a back sheet disposed below the back seal toward the back of the substrate.

The back junction solar cell may be formed in a heterojunction structure. The substrate of the back junction solar cell formed of a heterojunction structure may be formed of a crystalline semiconductor substrate, and the emitter portion formed of the first amorphous silicon layer and the back electric field portion formed of the second amorphous silicon layer may be positioned on the rear surface of the substrate. .

The back junction solar cell further includes a plurality of first electrodes connected at one end by a current collector for a first electrode, and a plurality of second electrodes connected at one end by a current collector for a second electrode. The first electrodes and the plurality of second electrodes are alternately positioned to contact the emitter portion and the backside electric field, respectively.

For example, the conductive adhesive film may include a first conductive adhesive film contacting a current collector for a first electrode of one solar cell and a second contacting current collector for a second electrode of another solar cell among two solar cells adjacent to each other. It may include a conductive adhesive film. In this case, the interconnector may contact both the first conductive adhesive film and the second conductive adhesive film.

The width of the first conductive adhesive film may be less than or equal to the width of the first electrode current collector, and the width of the second conductive adhesive film may be less than or equal to the width of the current collector for the second electrode.

The length of the first conductive adhesive film may be less than or equal to the length of the first electrode current collector, and the length of the second conductive adhesive film may be less than or equal to the length of the current collector for the second electrode.

The back junction solar cell extends in a second direction orthogonal to a first direction and is positioned in a space between a plurality of first electrodes connected to the current collector for the first electrode and the first electrode. Direction further includes a plurality of second electrodes having a first end connected to the current collector for the second electrode, wherein the first conductive adhesive film does not contact the first electrode, and the second conductive adhesive film is the second electrode. Not in contact with

The length of the interconnector may be formed to be equal to or less than the length of the first conductive adhesive film and the second conductive adhesive film.

The width of the interconnector may be formed larger than the distance between the first conductive adhesive film and the second conductive adhesive film adjacent to each other.

As another example, the conductive adhesive film includes a third conductive adhesive film in contact with the collector for the first electrode of one solar cell and the collector for the second electrode of the other solar cell, and the interconnector is a third conductive adhesive. Contact with the film.

In this case, the width of the third conductive adhesive film may be formed to be greater than or equal to the width of the interconnector, and the length of the interconnector may be formed to be equal to or less than the length of the third conductive adhesive film.

The back junction solar cell extends in a second direction perpendicular to the first direction and is positioned in a space between the plurality of first electrodes and the first electrode connected to the current collector for the first electrode and extends in the second direction. And a plurality of second electrodes having a first end connected to the current collector for the second electrode, wherein the third conductive adhesive film does not contact the first electrode and the second electrode.

The spacer may be positioned between two solar cells adjacent to each other, and the conductive adhesive film may include a groove in which a portion of the spacer is embedded.

The spacer is located in the space between two substrates adjacent to each other, or in the space between the current collectors for the first electrode and the second electrode adjacent to each other, or the space between the two substrates adjacent to each other and the current collector for the first electrodes adjacent to each other. And a space between the current collector for the second electrode.

When the spacer is located in the space between two substrates adjacent to each other, the space between the spacer and the interconnector may be filled with the front seal or the rear seal.

When the spacer is positioned in the space between the first electrode current collector and the second electrode current collector that are adjacent to each other, the space between the two substrates adjacent to each other may be filled with the front sealant or the rear sealant.

The spacer may be formed to have the same thickness as the substrate, or may be formed to a thickness of the sum of the thicknesses of the current collector and the conductive adhesive film, or may be formed to a thickness of the sum of the thicknesses of the substrate, the current collector and the conductive adhesive film.

When the spacer is formed to the same thickness as the substrate, the space between the interconnector and the spacer may be filled with a front seal or a rear seal.

And when the spacer is formed to a thickness of the sum of the thickness of the current collector and the conductive adhesive film, the space between the two substrates adjacent to each other may be filled with the front sealing material or the rear sealing material.

According to this feature, since the current collector and the interconnector can be directly connected by using the conductive adhesive film, tabbing can be performed at low temperature (140 ° C to 180 ° C).

And a thin substrate can be used. For example, when the thickness of the substrate is 200 mu m, the substrate bending amount is measured to be about 2.1 mm or more according to the conventional method of melting the flux by using hot air. However, in the case of the tableting method using the conductive adhesive film The substrate bending amount is measured to be about 0.5 mm.

Here, the amount of deflection can be expressed as a difference in height between a central portion of the substrate and a peripheral portion of the substrate on the lower surface of the substrate.

Such substrate warping phenomenon occurs more as the thickness of the substrate becomes thinner. For example, when the thickness of the substrate is 80 μm, the deflection amount of the substrate is measured to be about 14 mm or more according to the conventional method of melting the flux using hot air. However, in the case of the tableting method using the conductive adhesive film The substrate bending amount is measured to be about 1.8 mm.

If the substrate bending amount exceeds a certain range, for example, 2.5 mm, there is a problem such as cracking of the substrate inside the module or generation of bubbles in the subsequent lamination process. Therefore, when using the conventional method, It is impossible to form.

However, in the tableting method using the conductive adhesive film, since the deflection amount of the substrate can be remarkably reduced compared with the conventional one, it is possible to use a substrate having a thin thickness.

For example, when a tableting method using a conductive adhesive film is used, a substrate having a thickness of 80 mu m to 180 mu m can be used. Therefore, the material cost can be reduced by reducing the thickness of the substrate.

In addition, the conventional tabbing method using the flux outputs the solar cell module due to problems such as cracking at the interface of the current collector and the interconnector or peeling between various materials in the solder of the interconnector. Although this problem is lowered, the tabbing method using a conductive adhesive film can solve the above problems. Therefore, the reliability of the solar cell module can be maintained for a long time.

And since the conductive adhesive film absorbs the thermal stress applied to the interconnector, it is possible to prevent the electrical connection of the interconnector and the current collector from being damaged by the thermal stress, thereby further improving reliability and durability.

1 is a plan view of a solar cell module according to a first embodiment of the present invention, in which a rear sheet is removed.
Figure 2 is a perspective view of the main portion showing the configuration of the back junction type positive battery used in the solar cell module according to an embodiment of the present invention.
3 is a partial cross-sectional view of a solar cell module according to a first embodiment of the present invention.
4 is a partial cross-sectional view of the solar cell module according to the first modified embodiment of FIG. 3.
FIG. 5 is a partial cross-sectional view of the solar cell module according to the second modified embodiment of FIG. 3.
6 is a partial cross-sectional view of a solar cell module according to a third modified embodiment of FIG. 3.
7 is a plan view of a solar cell module according to a second embodiment of the present invention, which is a plan view showing a state in which a rear sheet is removed.
8 is a partial cross-sectional view of a solar cell module according to a second embodiment of the present invention.
9 is a partial cross-sectional view of the solar cell module according to the first modified embodiment of FIG. 8.
FIG. 10 is a partial cross-sectional view of the solar cell module according to the second modified embodiment of FIG. 8.
FIG. 11 is a partial cross-sectional view of the solar cell module according to the third modified embodiment of FIG. 8.
12 is a plan view of a solar cell module according to a third embodiment of the present invention, which is a plan view showing a state in which a rear sheet is removed.
FIG. 13 is a plan view of a solar cell module according to a fourth embodiment of the present invention, in which a rear sheet is removed.
FIG. 14 is a plan view of a solar cell module according to a fifth embodiment of the present invention, in which a rear sheet is removed.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention in the drawings, portions not related to the description are omitted, and like reference numerals are given to similar portions throughout the specification.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. When a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case directly above another portion but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

Next, a back junction solar cell module according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

First, the first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. 1 is a plan view of a solar cell module according to a first embodiment of the present invention, which is a plan view showing a state in which a rear sheet is removed, and FIG. 2 shows a configuration of a solar cell used in a back junction solar cell module of the present invention. It is a perspective view of the principal part, and FIG. 3 is a partial sectional view of the solar cell module which concerns on 1st Example of this invention.

As shown in Figures 1 to 3, the solar cell module according to the present embodiment is arranged on the rear of the plurality of back-junction solar cells 110, the solar cells 110 and electrically adjacent to the solar cells 110 A transparent member 150 disposed on the front seal 130 to protect the solar cells 110, the front seal 130 and the rear seal 140, and the light receiving surface of the solar cells 110. ) And a rear sheet 160 disposed below the rear sealant opposite to the light receiving surface.

1 and 3 only show two solar cells 110, the number of solar cells 110 is not limited.

As shown in FIG. 2, the back junction solar cell 110 used in the solar cell module has a crystalline semiconductor substrate 111 and an incident surface which is a surface of the crystalline semiconductor substrate 111 to which light is incident. (front surface) ', a front protective film 116a positioned on the front surface, the front surface field (FSF) 117 located on the front protective film 116a, an anti-reflection film located on the front electric field 117 118, on the rear passivation layer 116b and the rear passivation layer 116b which are positioned on the surface of the crystalline semiconductor substrate 111 that is opposite to the incident surface without being incident on the light (hereinafter, referred to as a 'rear surface'). A plurality of second amorphous silicon 119b and a first amorphous silicon layer 119a disposed on the rear protective layer 116b and spaced apart from the plurality of first amorphous silicon layer 119a. A plurality of first electrodes 112 and a current collector for the first electrode positioned on 119a (see FIG. 1) 114, and a plurality of second electrodes 113 and a current collector for a second electrode (see FIG. 1, 115) positioned on the second amorphous silicon layer 119b.

In FIG. 2, the first back junction solar cell 110 includes the front field unit 117, the second amorphous silicon layer 119b, and the rear passivation layer 116b, but the front field unit 117 is illustrated. ), The second amorphous silicon layer 119b and the rear passivation layer 116b may be omitted.

The first amorphous silicon layer 119a serves as an emitter portion, and the second amorphous silicon layer 119b serves as a back surface field (BSF). Therefore, hereinafter, the first amorphous silicon layer 119a is represented by an emitter portion, and the second amorphous silicon layer 119b is represented by a rear electric field portion.

The crystalline semiconductor substrate 111 is a crystalline semiconductor substrate made of silicon of a first conductivity type, for example, an n-type conductivity. At this time, the silicon is crystalline silicon such as monocrystalline silicon or polycrystalline silicon.

When the crystalline semiconductor substrate 111 has an n-type conductivity type, impurities of pentavalent elements such as phosphorus (P), arsenic (As), and antimony (Sb) are doped into the crystalline semiconductor substrate 111.

Alternatively, the crystalline semiconductor substrate 111 may be of a p-type conductivity type and may be made of a semiconductor material other than silicon. When the crystalline semiconductor substrate 111 has a p-type conductivity type, the crystalline semiconductor substrate 111 is doped with impurities of trivalent elements such as boron (B), gallium (Ga), and indium (In).

The incident surface of the crystalline semiconductor substrate 111 may have a textured surface.

In FIG. 2, only edge portions of the crystalline semiconductor substrate 111, the front passivation layer 116a, the front electric field unit 117, and the antireflective layer 118 are illustrated as texturing surfaces, but the crystalline semiconductor substrate 111 and the front passivation layer are substantially the same. 116a, the entire front surface 117 and the front surface of the antireflection film 118 have a texturing surface.

The front passivation layer 116a disposed on the front surface of the crystalline semiconductor substrate 111 may include any one of an intrinsic amorphous silicon (a-Si) film, a silicon nitride film (SiNx), and a silicon oxide film (SiOx). It may be formed to include.

The front passivation layer 116a moves toward the surface of the crystalline semiconductor substrate 111 by converting defects such as dangling bonds mainly present on and near the surface of the crystalline semiconductor substrate 111 into stable bonds. It performs a passivation function that reduces the dissipation of one charge by the defect. Thus, the amount of charge lost on or near the surface of the crystalline semiconductor substrate 111 is reduced.

If the thickness of the front passivation layer 116a is about 1 nm or more, since the front passivation layer 116a is uniformly applied to the entire surface of the crystalline semiconductor substrate 111, the passivation function can be satisfactorily performed, and the thickness of the front passivation layer 116a is about If it is 30 nm or less, the amount of light absorbed in the front passivation layer 116a may be reduced, thereby increasing the amount of light incident into the crystalline semiconductor substrate 111. Therefore, it is preferable that the front protective film 116a has a thickness of about 1 nm to 30 nm.

The front field part 117 positioned on the front passivation layer 116a is an impurity part in which impurities of the same conductivity type (eg, n-type) as the crystalline semiconductor substrate 111 are contained in a higher concentration than the crystalline semiconductor substrate 111. The impurity doping concentration of the electric field unit 117 may be about 10 ¹⁰ to 10 ²¹ atoms / cm 3.

The front field unit 117 may include any one of amorphous silicon, amorphous silicon oxide (a-SiOx), and amorphous silicon silicon (a-SiC).

As described above, when the front electric field part 117 is formed, a potential barrier is formed due to the difference in the impurity concentration between the crystalline semiconductor substrate 111 and the front electric field part 117. Field effect can be prevented.

In general, the energy band gaps of amorphous silicon oxide (a-SiOx) and amorphous silicon silicon (a-SiC) are about 2.1 and about 2.8, respectively, so the energy band gap of amorphous silicon oxide and amorphous silicon silicon is about Wider than amorphous silicon with an energy band gap of 1.7 to 1.9.

Therefore, when the front field unit 117 is made of amorphous silicon oxide (a-SiOx) or amorphous silicon silicon (a-SiC), the amount of light absorbed by the front field unit 117 itself is reduced, thereby reducing the amount of the crystalline semiconductor substrate ( The amount of light incident toward 111 increases further.

The anti-reflection film 118 located on the front electric field 117 increases the efficiency of the back junction solar cell 110 by reducing the reflectivity of light incident to the back junction solar cell 110 and increasing the selectivity of a specific wavelength region. .

The anti-reflection film 118 may be formed of a silicon nitride film (SiNx), a silicon oxide film (SiOx), or the like, and may have a single film structure or a multilayer film structure, and may be omitted as necessary.

The rear passivation layer 116b located directly on the rear side of the crystalline semiconductor substrate 111 performs the passivation function in the same manner as the front passivation layer 116a, so that the charges transferred toward the rear side of the crystalline semiconductor substrate 111 are dissipated by defects. Decrease.

The rear passivation layer 116b may be formed of amorphous silicon or the like in the same manner as the front passivation layer 116a.

The back passivation layer 116b has a thickness such that charges moved toward the back surface of the crystalline semiconductor substrate 111 may pass through the back passivation layer 116b and move to the plurality of rear electric field portions 119b or the emitter portions 119a. .

If the thickness of the rear passivation layer 116b is about 1 nm or more, since the rear passivation layer 116b is uniformly applied to the rear surface of the crystalline semiconductor substrate 111, a passivation effect may be further obtained, and the thickness of the rear passivation layer 116b is about 10 nm or less. The amount of light absorbed by the light passing through the rear surface crystalline semiconductor substrate 111 in the rear passivation layer 116b may be reduced, thereby increasing the amount of light re-incident into the crystalline semiconductor substrate 111.

Therefore, the rear protective film 116b preferably has a thickness of about 1 to 10 nm.

The plurality of backside electric fields 119b are regions in which impurities of the same conductivity type as those of the crystalline semiconductor substrate 111 are doped at a higher concentration than the crystalline semiconductor substrate 111. For example, the plurality of backside electric fields 119b may be n + impurity regions.

The plurality of rear electric field parts 119b are spaced apart from each other on the rear passivation layer 116b and extend in parallel to each other. In the present embodiment, the plurality of backside electric fields 119b may be formed of an amorphous semiconductor such as amorphous silicon (a-Si).

Similar to the front electric field 117, the rear electric field 119b moves holes toward the rear electric field 119b by a potential barrier due to a difference in impurity concentration between the crystalline semiconductor substrate 111 and the rear electric field 119b. On the other hand, it facilitates the movement of electrons toward the back field 119b.

Therefore, the amount of electric charge lost due to the recombination of electrons and holes in the rear electric field part 119b and its vicinity or the first electrode parts 112 and 114 and the second electrode parts 113 and 115 is reduced, and the electron movement is reduced. Acceleration increases the amount of electron movement to the back field 119b.

Here, the first electrode portions 112 and 114 include a plurality of first electrodes 112 and a first electrode current collector 114, and the second electrode portions 113 and 115 include a plurality of second electrodes. And a current collector 115 for the second electrode.

Each backside field portion 119b may have a thickness of about 10 nm to 25 nm. If the thickness of the rear electric field 119b is about 10 nm or more, a potential barrier that hinders the movement of holes may be better formed, and thus the charge loss may be further reduced. The amount of light absorbed may be reduced to increase the amount of light re-incident into the crystalline semiconductor substrate 111.

The plurality of emitter portions 119a are spaced apart from the plurality of rear electric field portions 119b on the rear surface of the crystalline semiconductor substrate 111 and extend in parallel with the plurality of rear electric field portions 119b.

Therefore, as shown in FIG. 2, the rear electric field part 119b and the emitter part 119a are alternately positioned on the crystalline semiconductor substrate 111.

Each emitter portion 119a is formed on the rear surface of the crystalline semiconductor substrate 111 and has a second conductivity type opposite to the conductivity type of the crystalline semiconductor substrate 111, for example, a p-type conductivity type. A semiconductor different from the semiconductor substrate 111, for example, amorphous silicon.

Thus, the emitter portion 119a forms a hetero junction as well as a p-n junction with the crystalline semiconductor substrate 111.

According to this configuration, the light generated by the light incident on the crystalline semiconductor substrate 111 due to the built-in potential difference due to the pn junction formed between the crystalline semiconductor substrate 111 and the plurality of emitter portions 119a. Electron-hole pairs, which are charges, are separated into electrons and holes, electrons move toward n-type and holes move toward p-type.

Therefore, when the crystalline semiconductor substrate 111 is n-type and the plurality of emitter portions 119a are p-type, the separated holes move through the rear passivation layer 116b toward each emitter portion 119a, and the separated electrons It penetrates through the rear passivation layer 116b and moves toward the plurality of backside field portions 119b having a higher impurity concentration than the crystalline semiconductor substrate 111.

Each emitter portion 119a may have a thickness of about 5 nm to 15 nm. If the thickness of the emitter portion 119a is about 5 nm or more, the pn junction may be formed better. If the thickness of the emitter portion 119a is about 15 nm or less, the amount of light absorbed in the emitter portion 119a may be reduced to re-integrate into the crystalline semiconductor substrate 111. It is possible to increase the amount of incident light.

On the other hand, since the rear passivation layer 116b formed of the intrinsic semiconductor material (intrinsic a-Si) containing little or no impurities is located under the plurality of emitter portions 119a and the plurality of backside electric field portions 119b, the crystalline semiconductor substrate The crystallization phenomenon is reduced when the emitter portion 119a and the rear electric field portion 119b are formed, as compared with the case where the plurality of emitter portions 119a and the plurality of rear electric field portions 119b are positioned directly on the 111.

Thus, the characteristics of the plurality of emitter portions 119a and the plurality of rear electric field portions 119b positioned on the amorphous silicon are improved.

The first electrode 112 in contact with the emitter portion 119a extends in the second direction X-X 'along the emitter portion 119a and is electrically connected to the emitter portion 119a. Charges, for example, holes, that have moved toward the turret 119a are collected.

The second electrode 113 contacting the rear electric field 119b extends in the second direction X-X ′ along the rear electric field 119b and is electrically connected to the plurality of rear electric fields 119b. And collect charges, for example, electrons, which move toward the corresponding backside field portion 119b.

The plurality of first and second electrodes 112 and 113 may include nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), and indium (In). It may be made of at least one conductive material selected from the group consisting of titanium (Ti), gold (Au), and combinations thereof, but may be made of other conductive metal materials.

On the other hand, although not shown in Figure 2, the emitter portion 119a is also located in the region where the first electrode current collector 114 is formed, the rear electric field portion 119b is the second electrode current collector 115 is formed It is also located in the area.

Here, the first electrode current collector 114 is in electrical contact with the emitter portion 119a in contact with the emitter portion 119a, and is located at the first corner of the crystalline semiconductor substrate 111 and is connected to the second direction. It extends in the first orthogonal direction (Y-Y ') to physically connect the first ends of the first electrodes (112).

The second electrode current collector 115 is in contact with the rear electric field part 119b and electrically connected to the rear electric field part 119b, and is positioned at a second corner of the crystalline semiconductor substrate 111. It extends in a first direction (Y-Y ') orthogonal to and physically connects the first ends of the second electrodes 113.

Accordingly, the first electrode current collector 114 collects the charges transferred to the first electrode 112, and the second electrode current collector 115 collects the charges transferred to the second electrode 113.

The first electrode current collector 114 and the second electrode current collector 115 of such a configuration may be formed of the same material as the first electrode 112 and the second electrode 113.

The back sheet 160 protects the solar cells 110 from the external environment by preventing moisture from penetrating at the rear of the solar cell module. The back sheet 160 may have a multilayer structure such as a layer for preventing moisture and oxygen penetration, a layer for preventing chemical corrosion, and a layer having insulation properties.

The front sealer 130 and the rear sealer 140 are bonded to each other in a state in which they are disposed on the upper and lower portions of the solar cells 110, respectively, and are integrated with the solar cells 110, and the front sealant 130 and the rear sealant ( 140 prevents corrosion of the solar cells 110 due to moisture penetration and protects the solar cells 110 from impact.

In an embodiment of the present invention, the front sealant 130 and the rear sealant 140 may be made of the same material.

For example, the front seal 130 and the rear seal 140 may be formed of a cured siloxane including a material obtained by heat treatment of a liquid compound through heat treatment, for example, poly dialkyl siloxane (PDMS).

When a liquid compound, ie, a liquid siloxane, is applied on the solar cells 110, some of the applied siloxane precursors are filled in the spaces between the solar cells 110 due to fluidity, and are cured through heat treatment in this state.

Alternatively, the front sealant 130 and the rear sealant 140 may be made of a material such as ethylene vinyl acetate (EVA) manufactured in the form of a film.

Alternatively, the front seal 130 and the rear seal 140 may be made of different materials.

For example, the front seal 130 may be made of ethylene vinyl acetate in the form of a film, while the back seal 140 may be made of cured siloxane.

The transparent member 150 positioned on the front seal 130 is made of tempered glass having a high transmittance and excellent breakage prevention function. At this time, the tempered glass may be a low iron tempered glass having a low iron content. The transparent member 150 may be embossed with an inner surface to increase light scattering effect.

The interconnector 120 is made of a conductive metal and electrically connects adjacent solar cells 110. At this time, the interconnector 120 may further include a solder made of a lead-free conductive metal containing up to 1,000 ppm of lead, or a lead solder coated on the surface of the conductive metal .

To electrically connect adjacent solar cells 110, the interconnector 120 is in contact with the conductive adhesive film.

In the present exemplary embodiment, the conductive adhesive film may include the first conductive adhesive film CF1 in contact with the first electrode current collector 114, and the second conductive adhesive film CF2 in contact with the second electrode current collector 115. Is formed.

Hereinafter, the junction structure between the interconnector and the current collector will be described in detail.

The first conductive adhesive film CF1 is positioned on the first electrode current collector 114, and the second conductive adhesive film CF2 is positioned on the second electrode current collector 115.

The 1st electroconductive adhesive film CF1 contains the resin (CF1-1) and the some electroconductive particle (CF1-2) disperse | distributed to resin (CF1-1).

Resin (CF1-1) will not be specifically limited if it is a material which has adhesiveness. However, in order to improve adhesive reliability, it is preferable to use a thermosetting resin.

As the thermosetting resin, at least one resin selected from an epoxy resin, a phenoxy resin, an acrylic resin, a polyimide resin, and a polycarbonate resin may be used.

Resin (CF1-1) can contain a well-known hardening | curing agent and a hardening accelerator as arbitrary components other than a thermosetting resin.

For example, the resin CF1-1 may be a silane coupling agent or a titanate to improve adhesion between the current collector 114 for the first electrode and the interconnector 120. Modified materials, such as a system coupling agent and an aluminate coupling agent, can be contained.

In addition, the resin (CF1-1) may contain a dispersant such as calcium phosphate or calcium carbonate in order to improve the dispersibility of the conductive particles (CF1-2), and in order to control the elastic modulus, acrylic rubber, silicone rubber, urethane, or the like. It may contain a rubber component.

As long as electroconductive particle CF1-2 has electroconductivity, the material will not be specifically limited.

The conductive particles CF1-2 may be composed of radial metal particles of various sizes. Herein, the 'radial metal particles' may be at least one selected from the group consisting of copper (Cu), silver (Ag), gold (Au), iron (Fe), nickel (Ni), lead (Pb), zinc (Zn), cobalt Refers to metal particles in which a plurality of protrusions are irregularly formed on the surface of metal particles having a substantially spherical shape composed mainly of at least one metal selected from titanium (Ti) and magnesium (Mg).

In order to smoothly flow the current between the interconnector 120 and the current collector 114 for the first electrode, the first conductive adhesive film CF1 has radial metal particles having a size larger than the thickness of the resin CF1-1. It may include at least one.

According to this configuration, a portion of the radial metal particles formed to a size larger than the thickness of the resin CF1-1 is embedded in the current collector 114 and / or the interconnector 120 for the first electrode.

Therefore, the contact area between the radial metal particles and the first electrode current collector 114 and / or the radial metal particles and the interconnector 120 is increased, thereby reducing contact resistance. When the contact resistance decreases, the current flows between the current collector 114 for the first electrode and the interconnector 120.

In the above description, the conductive particles CF1-2 are formed of radial metal particles, but the conductive particles CF1-2 are formed of copper (Cu), silver (Ag), gold (Au), iron (Fe), It may be made of metal-coated resin particles containing, as a main component, at least one metal selected from nickel (Ni), lead (Pb), zinc (Zn), cobalt (Co), titanium (Ti), and magnesium (Mg).

When the electroconductive particle CF1-2 consists of metal coating resin particle, the electroconductive particle CF1-2 may be formed in circular or elliptical shape.

On the other hand, although not shown, the conductive particles (CF1-2) may be in physical contact with each other and the adjacent ones.

In terms of connection reliability after the resin (CF1-1) has cured, the compounding quantity of the conductive particles (CF1-2) dispersed in the resin (CF1-1) is 0.5 volume based on the total volume of the first conductive adhesive film CF1. It is preferable to set it as% -20 volume%.

If the amount of the conductive particles CF1-2 is less than 0.5% by volume, the physical contact with the current collector 114 for the first electrode decreases, so that current may not flow smoothly, and the amount of the compounding amount exceeds 20% by volume. If the lower surface of the resin (CF1-1) relative amount is reduced, the adhesive strength may be lowered.

The first conductive adhesive film CF1 is adhered to the first electrode current collector 114 in a direction parallel to the first electrode current collector 114.

At this time, the tabbing operation includes pre-bonding the first conductive adhesive film CF1 to the current collector 114 for the first electrode, and interconnector 120 and the first conductive adhesive film ( According to the final step of final bonding (CF1).

When the tabbing operation is performed using the first conductive adhesive film CF1, the conditions of heating temperature and pressurization pressure are not particularly limited as long as the electrical connection can be secured and the adhesive force can be maintained.

For example, the heating temperature in the preliminary bonding step can be set to about 100 ° C. or less, and the heating temperature in the final bonding step is in the temperature range where the resin (CF1-1) is cured, such as in the range of 140 ° C. to 180 ° C. Can be set.

In addition, the pressurization pressure in the preliminary bonding step may be set to about 1 MPa, and the pressurizing pressure in the final bonding step is such that the first electrode current collector 114 and the interconnector 120 are connected to the first conductive adhesive film CF1. It can be set to a range that is sufficiently in close contact, for example, approximately 2 MPa to 3 MPa.

In this case, the pressurized pressure may allow at least a portion of the conductive particles CF1-2 to be immersed into the current collector 114 for the first electrode and / or the interconnector 120.

In addition, the heating and pressing time in the preliminary bonding step may be set to about 5 seconds, and the heating and pressing time in the final bonding step may cause damage to the current collector 114 for the first electrode and the interconnector 120 due to heat. Or a range that does not deteriorate, for example, about 10 seconds.

On the other hand, the width of the first conductive adhesive film CF1, that is, the width in the second direction X-X 'is formed to be equal to or less than the width of the first electrode current collector 114, and the second conductive adhesive film CF2. ) May be less than or equal to the width of the current collector 115 for the second electrode.

According to this configuration, the first conductive adhesive film CF1 does not contact the first electrode 112, and the second conductive adhesive film CF2 does not contact the second electrode 113.

In addition, the first conductive adhesive film CF1 is not in contact with the second electrode 113, and the second conductive adhesive film CF2 is not in contact with the first electrode 113.

The length of the first conductive adhesive film CF1, that is, the length measured in the first direction Y-Y ′ is formed to be equal to or less than the length of the first electrode current collector 114, and the second conductive adhesive film CF2. The length of the second electrode may be less than or equal to the length of the current collector 115 for the second electrode.

The length of the interconnector 120 may be less than or equal to the length of the first conductive adhesive film CF1 and the second conductive adhesive film CF2.

Meanwhile, the width of the interconnector 120 may be greater than a distance between the first conductive adhesive film CF1 and the second conductive adhesive film CF2 adjacent to each other.

In this case, the width of the interconnector 120 considers an area where the interconnector 120 and the first conductive adhesive film CF1 overlap and an area where the interconnector 120 and the second conductive adhesive film CF2 overlap. It can form in an appropriate range.

In the interconnector 120, a slit or hole 122 may be formed for the purpose of reducing strain due to heat shrinkage and expansion.

When the back seal 140 is formed of hardened siloxane, the back seal 140 may be filled between two solar cells adjacent to each other.

However, in contrast, when the front sealant 130 and the rear sealant 140 are formed of ethylene vinyl acetate or hardened siloxane, the front sealant 130 may be filled in the space, and the front sealant 130 and the rear sealant may be filled. Depending on the material of 140, the front seal 130 and the back seal 140 may be filled together.

Hereinafter, various modified embodiments of FIG. 3 will be described with reference to FIGS. 4 to 6.

The solar cell module of FIGS. 4 to 6 is the same as the embodiment of FIG. 3 except that the spacer 170 is positioned between two adjacent solar cells 110. Therefore, only the spacer 170 will be described below.

The spacer 170 is positioned in a space between the first electrode current collector 114 and the second electrode current collector 115 adjacent to each other as shown in FIG. 4, or two adjacent spacers 170 as shown in FIG. 5. As shown in FIG. 6, the space between two substrates 111 adjacent to each other and the first electrode current collector 114 and the second electrode current collector 115 adjacent to each other. It can be located in the space between.

As shown in FIG. 4, when the spacers 170 are located in the space between the first electrode current collector 114 and the second electrode current collector 115 adjacent to each other, the spacers 170 may be disposed in the current collectors 114,. 115) and the thicknesses of the thicknesses of the conductive adhesive films CF1 and CF2 may be formed, and in the case of forming the back seal 140 with hardened siloxane, the back surface may be formed in a space between two substrates 111 adjacent to each other. Sealing material 140 may be filled.

In contrast, however, when the front seal 130 and the rear seal 140 are formed of one of ethylene vinyl acetate or hardened siloxane, the front seal 130 may be formed in a space between two adjacent substrates 111. The front seal 130 and the rear seal 140 may be filled together according to the materials of the front seal 130 and the rear seal 140.

As shown in FIG. 5, when the spacer 170 is positioned in a space between two substrates 111 adjacent to each other, the spacer 170 may be formed to have the same thickness as the substrate 111, and the spacer 170 The back seal 140 may be filled in a space between the interconnector 120 and the interconnector 120.

Alternatively, the front seal 130 may be filled in the space between the spacer 170 and the interconnector 120, and the front seal 130 and the rear seal 140 may be filled together.

As shown in FIG. 6, the spacer 170 is positioned in a space between two substrates 111 adjacent to each other and a space between the first electrode current collector 114 and the second electrode current collector 115 adjacent to each other. In this case, the spacer 170 may be formed to a thickness of the sum of the thicknesses of the substrate 111, the current collectors 114 and 115, and the conductive adhesive films CF1 and CF2.

On the other hand, according to the embodiment of the present invention, the gap between the adjacent solar cells 110 and electrical insulation is made by the spacer 170. Therefore, when viewed from the light receiving surface side of the solar cell module, the interconnector 120 may be observed as a space between adjacent solar cells 110.

However, the interconnector 120 is made of a conductive metal of a different color from the solar cells 110. Therefore, in order to enhance aesthetics, the spacer 170 may treat the surface facing the light receiving surface in the same color as the semiconductor substrate 111 of the solar cell 110 or the same color as the backsheet, for example, black or white.

The solar cell module having such a configuration forms a front seal 130 on the transparent member 150, and arranges a plurality of back junction solar cells 110 on the front seal 130 at regular intervals, and then, for the first electrode. The first conductive adhesive film CF1 and the second conductive adhesive film CF2 are disposed on the current collector 114 and the current collector 115 for the second electrode, respectively, and the interconnector 120 is connected to the first conductive adhesive film ( CF1) and the second conductive adhesive film (CF2) to form a back seal 140 on it, the rear sheet 160 is placed on the back seal 140, and then subjected to the lamination process Can be.

In this case, the front sealant 130 and the rear sealant 140 may be formed by applying and curing a liquid siloxane precursor, for example, dimethylsilyloxyacrylate.

When the liquid siloxane precursor is applied in this way, a portion of the applied liquid siloxane precursor is filled in the space between the adjacent solar cells 110.

Hereinafter, a solar cell module according to a second embodiment of the present invention will be described with reference to FIGS. 7 and 8.

In the above-described first embodiment, the first conductive adhesive film CF1 is used to electrically connect the interconnector 120 to the current collector 114 for the first electrode, and the interconnector 120 is used for the second electrode. The second conductive adhesive film CF2 was used to electrically connect the current collector 115.

However, in the present exemplary embodiment, the first electrode current collector 114 and the second electrode current collector 115 are electrically connected to the interconnector 120 using only the third conductive adhesive film CF3. In the description of the second embodiment, the same components as those of the above-described first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

To this end, the width of the third conductive adhesive film CF3 may be formed to be greater than or equal to the width of the interconnector 120, and the length of the interconnector 120 may be less than or equal to the length of the third conductive adhesive film CF3. Can be.

According to this structure, the third conductive adhesive film CF3 may not be in contact with the first electrode 112 and the second electrode 113, and the interconnector 120 may include a slit or a hole 122. have.

Hereinafter, modified embodiments of FIG. 8 will be described with reference to FIGS. 9 to 11.

The solar cell module according to the second embodiment may also include the spacer 170 as in the first embodiment described above.

The spacer 170 is positioned in a space between the first electrode current collector 114 and the second electrode current collector 115 adjacent to each other as shown in FIG. 9, or as shown in FIG. 10. As shown in FIG. 11, the space between two substrates 111 adjacent to each other and the first electrode current collector 114 and the second electrode current collector 115 adjacent to each other. It can be located in the space between.

As shown in FIG. 9, when the spacers 170 are located in the space between the first electrode current collector 114 and the second electrode current collector 115 adjacent to each other, the spacers 170 may be disposed in the current collectors 114,. It may be the same as the thickness of 115 or thicker than the thickness of the current collector (114, 115).

When the thickness of the spacer 170 is thicker than the thickness of the current collectors 114 and 115, the third conductive adhesive film CF3 may include a groove H1 in which a portion of the spacer 170 is embedded.

When the back seal 140 is formed of hardened siloxane, the back seal 140 may be filled in a space between two substrates 111 adjacent to each other.

However, the front sealant 130 may be filled in the space between the two substrates 111 adjacent to each other, and the front sealant 130 and the rear sealant 140 may be filled together.

As shown in FIG. 10, when the spacer 170 is located in a space between two substrates 111 adjacent to each other, the spacer 170 may be formed to have the same thickness as the substrate 111, and the spacer 170 The back sealing material 140 may be filled in the space between the third conductive adhesive film CF3.

However, the front sealing material 130 may be filled in the space between the spacer 170 and the third conductive adhesive film CF3, and the front sealing material 130 and the rear sealing material 140 may be filled together.

As shown in FIG. 11, the spacer 170 is positioned in a space between two substrates 111 adjacent to each other and a space between the first electrode current collector 114 and the second electrode current collector 115 adjacent to each other. In this case, the spacer 170 may be formed to have a thickness equal to or greater than the sum of the thicknesses of the substrate 111 and the current collectors 114 and 115.

When the thickness of the spacer 170 is thicker than the thickness of the substrate 111 and the current collectors 114 and 115, the third conductive adhesive film CF3 may include a groove H1 in which a portion of the spacer 170 is embedded. Can be.

Hereinafter, a solar cell module according to a third embodiment of the present invention will be described with reference to FIG. 12. 12 is a plan view of a solar cell module according to a third embodiment of the present invention, which is a plan view showing a state in which a rear sheet is removed.

The solar cell module of the present embodiment is configured in the same manner as the embodiment of FIG. 7 except that the back junction solar cells 110 adjacent to each other are electrically connected by a plurality of interconnectors 120.

That is, as shown in FIG. 12, the third conductive adhesive film CF3 is in contact with the current collector 115 for the second electrode of the back junction solar cell 110 positioned on the left side in some areas, and also in some areas. In contact with the first electrode current collector 114 of the back junction solar cell 110 located on the right side.

On the third conductive adhesive film CF3, two or more interconnectors 120 are positioned along the length direction of the third conductive adhesive film CF3, that is, in the first direction Y-Y ′.

As such, an embodiment using at least two interconnectors 120 may be equally applicable to the above-described embodiment of FIG. 1.

In the embodiment of FIG. 12, two or more interconnectors 120 are bonded to one third conductive adhesive film CF3.

However, as shown in the third embodiment of FIG. 13, the third conductive adhesive film CF3 may also be dividedly formed like the interconnector 120.

In this case, the first electrode current collector 114 of the solar cell 110 adjacent to the second electrode current collector 115 of one solar cell 110 may include two or more third conductive adhesive films CF3 and It may be electrically connected by the same number of interconnectors 120 as the third conductive adhesive film (CF3).

On the contrary, as shown in the fourth embodiment of FIG. 14, the first electrode current collector 114 of the solar cell 110 adjacent to the second electrode current collector 115 of one solar cell 110. May be in contact with at least two third conductive adhesive films CF3, and at least two third conductive adhesive films CF3 may be in contact with one interconnector 120.

Although not shown, the back junction solar cell used in the solar cell module of the present invention may have a non-bus bar structure without a current collector, for example, a bus bar.

In a back-junction solar cell having a non-busbar structure, the first electrode part includes only a plurality of first electrodes extending in a second direction orthogonal to the first direction, and the second electrode part alternately with the first electrodes. It includes only a plurality of second electrodes extending in the second direction to be arranged alternately.

And the first electrodes adjacent to each other are not physically connected to each other by the electrode material forming the first electrode, and the second electrodes adjacent to each other are not physically connected to each other by the electrode material forming the second electrode.

This structure appears only in the non-bus bar structure, the back-junction solar cell of the non-bus bar structure can reduce the material cost and the number of processes according to the bus bar formation.

In a back-junction solar cell having a non-busbar structure, the conductive adhesive film is in physical contact with one ends of the plurality of first electrodes or one ends of the plurality of second electrodes, and one end of the plurality of first electrodes. Or one ends of the plurality of second electrodes are electrically connected.

In addition, one ends of the plurality of first electrodes and one end of the plurality of second electrodes may have contact portions having an enlarged line width, respectively.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

110: back junction solar cell 111: substrate
112: first electrode 113: second electrode
114: current collector for first electrode 115: current collector for second electrode
120: interconnect 130: front seal
140: back seal 150: transparent member
160: back sheet CF1-CF3: first to third conductive adhesive film

Claims

A substrate, a current collector for a first electrode positioned in a first corner of the rear surface of the substrate and extending in a first direction, and a current collector for a second electrode positioned in a second corner of the rear surface of the substrate and extended in the first direction A plurality of back junction solar cells each including;
At least one conductive adhesive film in contact with a second electrode current collector of one solar cell and a first electrode current collector of another solar cell among two solar cells adjacent to each other;
At least one interconnector in contact with the at least one conductive adhesive film and electrically connecting two adjacent solar cells;
A front seal and a back seal to protect the solar cells;
A transparent member disposed above the front seal member toward the front surface of the substrate; And
A back sheet disposed below the back seal toward the back of the substrate
Solar cell module comprising a.

In claim 1,
The back junction solar cell is a solar cell module formed of a heterojunction structure.

3. The method of claim 2,
The substrate of the back junction solar cell is made of a crystalline semiconductor substrate, the back side of the substrate is a solar cell module having an emitter portion formed of a first amorphous silicon layer and a rear electric field formed of a second amorphous silicon layer.

4. The method of claim 3,
The back junction solar cell further includes a plurality of first electrodes connected at one end by the current collector for the first electrode, and a plurality of second electrodes connected at one end by the current collector for the second electrode, The plurality of first electrodes and the plurality of second electrodes are alternately positioned alternately, and contact the emitter unit and the rear electric field, respectively.

delete

In claim 1,
The width of the conductive adhesive film is a solar cell module is formed more than the width of the interconnector.

In claim 1,
The length of the interconnector is a solar cell module is formed to less than the length of the conductive adhesive film.

In claim 1,
A first end extending in a second direction perpendicular to the first direction and positioned in a space between the plurality of first electrodes connected to the current collector for the first electrode and the first electrode and extending in the second direction; The solar cell module of claim 1, further comprising a plurality of second electrodes connected to the current collector for the second electrode, wherein the conductive adhesive film does not contact the first electrode and the second electrode.

The method according to any one of claims 1 to 4 and 12 to 14,
A solar cell module, wherein a spacer is located between two adjacent solar cells.

16. The method of claim 15,
The conductive adhesive film is a solar cell module having a groove in which a portion of the spacer is embedded.

16. The method of claim 15,
The spacer is positioned in a space between two substrates adjacent to each other, the space between the spacer and the interconnector is filled with the front sealing material or the rear sealing material.

16. The method of claim 15,
The spacer is positioned in the space between the current collector for the first electrode and the current collector for the second electrode adjacent to each other, the space between the two substrates adjacent to each other is filled with the front sealing material or the rear sealing material.

16. The method of claim 15,
The spacer is located in a space between two adjacent substrates and a space between the adjacent current collector for the first electrode and the second electrode collector.

16. The method of claim 15,
The spacer is formed to the same thickness as the substrate, the space between the interconnector and the spacer is filled with the front sealing material or the back sealing material solar cell module.

16. The method of claim 15,
The spacer is formed to have a thickness of the sum of the thickness of the current collector and the conductive adhesive film, the space between the two adjacent substrates are filled with the front seal or the back seal member.

16. The method of claim 15,
The spacer is formed of a thickness of the sum of the thickness of the substrate, the current collector and the conductive adhesive film.