KR20120044541A

KR20120044541A - Conductive film, solar cell panel with the same and manufacturing method thereof

Info

Publication number: KR20120044541A
Application number: KR1020100105856A
Authority: KR
Inventors: 김종대; 홍종경
Original assignee: 엘지전자 주식회사
Priority date: 2010-10-28
Filing date: 2010-10-28
Publication date: 2012-05-08
Also published as: WO2012057516A2; WO2012057516A3

Abstract

PURPOSE: A conductive adhesive film, a solar cell panel, and a method for manufacturing the panel are provided to suppress the reduction of an output by preventing misalignment. CONSTITUTION: An interconnector(20) electrically connects adjacent solar cells(10). A front protection layer(30a) and a rear protection layer(30b) protect the solar cells. A transparent member(40) is arranged on the upper side of the front protection layer. A rear sheet(50) is arranged on the lower side of the rear protection layer and protects the solar cells from the external environment by preventing moisture from penetrating the rear of the solar cell panel.

Description

A conductive adhesive film, a solar cell panel having the film and a manufacturing method of the panel {CONDUCTIVE FILM, SOLAR CELL PANEL WITH THE SAME AND MANUFACTURING METHOD THEREOF}

The present invention relates to a conductive adhesive film, a solar cell panel electrically connecting adjacent solar cells using the film, and a method of manufacturing the solar cell panel.

Photovoltaic power generation, which converts light energy into electrical energy using a photoelectric conversion effect, is widely used as a means for obtaining pollution-free energy. And with the improvement of the photoelectric conversion efficiency of a solar cell, the photovoltaic power generation system which uses a some solar cell panel is installed also in a private house.

The solar cell panel includes an interconnector for electrically connecting a plurality of solar cells, a front protective member and a rear protective member for protecting the solar cells, and a sealing member for sealing the solar cells between the protective members.

The interconnector may be made of a conductive metal, or may be made of a conductive metal and a solder coated on the surface of the metal, and may be connected to an electrode part of a solar cell by a method such as infrared rays, hot air, local heating materials, or a laser.

However, in using the solar cell panel, the light receiving surface of the solar cell is reduced by the interconnector. That is, since the light receiving surface of the solar cell is reduced by the area where the interconnector is installed, the photoelectric conversion efficiency of the solar cell panel is reduced.

In order to minimize this problem, recently, solar cells are electrically connected to each other by using an interconnector having irregularities formed on a surface thereof, so that light incident on the uneven surface of the interconnector is incident on the uneven surface of the light. The solar panel is configured to be re-incident on the light-receiving surface after the reflection by the scattering effect.

On the other hand, a technique for performing a tabbing process at a low temperature by using a conductive adhesive film when bonding the interconnector and the electrode portion has been developed.

The technical problem to be achieved by the present invention is to provide a conductive adhesive film with improved electrical conductivity.

Another technical problem of the present invention is to provide a solar cell panel with improved output.

Another technical problem of the present invention is to provide a method of manufacturing a solar cell panel.

According to one aspect of the invention, the conductive adhesive film is a resin having an adhesive; A plurality of conductive particles dispersed in the resin and electrically connecting the two electrode parts; And a plurality of conductive fillers dispersed in the resin and electrically connecting adjacent conductive particles.

The conductive filler is contained in an amount of 0.01% by weight or more based on the total weight of the conductive adhesive film, and has graphene, carbon nanotube, metallic nanowire, and metal wire having an aspect ratio of 2 or more. wire) and at least one selected from metal particles.

At least a part of the conductive filler is located in the space between the conductive particles and is located in a direction not parallel to the thickness direction of the resin. At this time, at least a part of the conductive filler may be in contact with the conductive particles.

The solar cell panel includes a plurality of solar cells including a substrate and a plurality of electrode portions positioned on a surface of the substrate; An interconnector for electrically connecting electrode portions of adjacent solar cells; And a conductive adhesive film comprising a resin and a plurality of conductive particles dispersed in the resin, and compressed between the electrode portion and the interconnector to electrically connect the electrode portion and the interconnector. At this time, the conductive adhesive film further includes a conductive filler dispersed in the resin.

At least a portion of the conductive filler is located in a direction that is not perpendicular to the electrode portion and the interconnector in the space between the conductive particles and is in contact with the electrode portion, the interconnector or the conductive particle. According to this structure, the electrical connection between adjacent conductive particles is made by the filler, and the electrical connection between the electrode portion and the interconnector is made by the conductive particles and the filler.

The electrode part includes a front electrode part located at the front of the substrate and a rear electrode part located at the rear of the substrate.

The front electrode part may include a plurality of front electrodes and a plurality of front electrode current collectors positioned in a direction crossing the front electrodes, and the front electrode and the front electrode current collectors are connected to an emitter part located at the front of the substrate. .

The rear electrode portion includes a rear electrode and a rear electrode current collector disposed on the rear side of the substrate, and the rear electrode current collector is positioned in a direction parallel to the current collector for the front electrode.

The solar cell panel of such a configuration includes a temporary pressing step of pressing and compressing a conductive adhesive film including a resin and a plurality of conductive particles and a plurality of conductive fillers dispersed in the resin; An alignment and provision fixing step of aligning and provisionally fixing the interconnector to the pressed conductive adhesive film; And a main pressing step of main pressing the interconnector and the conductive adhesive film such that the electrode portion and the interconnector are electrically connected by the conductive adhesive film, wherein the main pressing step includes a heating tool. It can be produced by a method for producing a solar cell panel comprising pressing the interconnector with a tool to melt the resin of the conductive adhesive film.

The main compression step may include pressurizing the interconnector for 5 to 15 seconds at a pressure of 1.0 MPa to 5.0 MPa using the heating tool heated to a temperature of 140 ° C. to 200 ° C., wherein the pressure bonding step is 60 Pressing the conductive adhesive film for 1 second to 10 seconds at a pressure of 0.5 MPa to 1.5 MPa using a heating tool heated to a temperature of ℃ to 120 ℃.

According to this feature, the tabbing operation can be carried out at a low temperature (140 ℃ to 200 ℃). Tabbing in such a low temperature process allows tabbing to be carried out below the temperature at which the solder is melted, thus creating good electrical connections regardless of whether the interconnect material is lead-free or flexible. Even if a plurality of irregularities are formed on the surface of the interconnector, the irregularities can be maintained well after tabbing.

In addition, bowing and damage to the substrate can be prevented as compared with the case of performing tabbing operation using soldering.

In addition, since no flux is used, a uniform adhesive force can be maintained, and misalignment can be prevented, thereby reducing output reduction.

In addition, the filler dispersed in the resin (filler) serves as a bridge (bridge) between the conductive particles to improve the conductivity, it is possible to improve the output of the solar cell module.

1 is an exploded perspective view of a solar cell panel according to an embodiment of the present invention.
FIG. 2 is a schematic diagram illustrating an electrical connection relationship of a plurality of solar cells in the solar cell panel of FIG. 1.
3 is an exploded perspective view illustrating main parts of the solar cell panel illustrated in FIG. 1.
4 is a graph showing melting temperatures according to solder materials.
5 is a cross-sectional view according to an embodiment of the conductive adhesive film.
6 is a cross-sectional view illustrating the assembled state of FIG. 3.
7 is a process chart showing a manufacturing method of a solar cell panel according to an embodiment of the present invention.

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 the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. 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.

On the contrary, when a part is "just above" another part, there is no other part in the middle. In addition, when a part is formed "overall" on another part, it includes not only being formed in the whole surface of another part but also not formed in a part of an edge.

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

1 is an exploded perspective view of a solar cell panel according to an embodiment of the present invention. Referring to FIG. 1, the solar cell panel 100 includes a plurality of solar cells 10, an interconnector 20 electrically connecting adjacent solar cells 10, and a front passivation layer protecting the solar cells 10. 30a and the rear passivation layer 30b, the transparent member 40 disposed on the front passivation layer 30a toward the light receiving surface of the solar cells 10, and the rear sheet disposed under the rear passivation layer 30b on the opposite side of the light receiving surface ( back sheet) 50.

The back sheet 50 protects the solar cell 10 from the external environment by preventing moisture from penetrating at the rear of the solar cell panel 10. The back sheet 50 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.

In the case of a double-sided light-receiving solar cell, it is also possible to use light-transmissive glass or resin instead of the back sheet 50.

The front passivation layer 30a and the back passivation layer 30b are integrated with the solar cells 10 by lamination in a state where they are disposed on the front surface and the back surface of the solar cells 10, respectively. It prevents corrosion due to moisture penetration and protects the solar cell 10 from impact. The front and rear passivation layers 30a and 30b may be made of a material such as ethylene vinyl acetate (EVA).

The transparent member 40 positioned on the front protective film 30a is made of tempered glass having a high transmittance and excellent breakage preventing function. In this case, the tempered glass may be a low iron tempered glass having a low iron content. The transparent member 40 may be embossed with an inner surface to increase the light scattering effect.

The plurality of solar cells 10 are arranged in a matrix structure as shown in FIG. 1, and the number of solar cells 10 arranged in the row and column directions can be adjusted.

The plurality of solar cells 10 are electrically connected by interconnectors 20 as shown in FIG. 2.

More specifically, in a state in which the plurality of solar cells 10 are disposed adjacent to each other, an electrode portion formed on a front surface of one solar cell is electrically connected to an electrode portion formed on a rear surface of an adjacent solar cell by an interconnector 20. Is connected.

Hereinafter, this embodiment will be described in more detail with reference to FIG. 3. 3 is an exploded perspective view illustrating main parts of the solar cell panel illustrated in FIG. 1.

Referring to the drawings, the solar cell 10 includes a substrate 11, a front surface of the substrate 11, for example, an emitter portion 12 positioned on a light receiving surface on which light is incident, and a plurality of front surfaces positioned on the emitter portion 12. The plurality of front electrode current collectors 14, the front electrode 13, and the front electrode current collector 14, which are positioned on the electrode 13 and the emitter portion 12 and intersect the front electrode 13, respectively. The antireflection film 15 positioned on the emitter portion 12 where the light is not positioned, the rear electrode 16 located on the opposite side of the light receiving surface, and the same plane or rear surface of the rear electrode 16 as the rear electrode 16; It includes a current collector 17 for the rear electrode.

The solar cell 10 may further include a back surface field (BSF) part formed between the back electrode 15 and the substrate 11. The backside electric field is a region in which impurities of the same conductivity type as the substrate 11 are doped at a higher concentration than the substrate 11, for example, a p + region.

This backside field acts as a potential barrier. Therefore, the electrons and holes are recombined and extinguished at the rear side of the substrate 11, thereby improving efficiency of the solar cell.

The substrate 11 is a semiconductor substrate made of silicon of a first conductivity type, for example a p-type conductivity type. In this case, the silicon may be monocrystalline silicon, polycrystalline silicon, or amorphous silicon. When the substrate 11 has a p-type conductivity type, it contains impurities of trivalent elements such as boron (B), gallium (Ga), indium (In), and the like.

Although not shown, the surface of the substrate 11 may be formed as a texturing surface having a plurality of irregularities.

When the surface of the substrate 11 is formed as a texturing surface, the light reflectance at the light receiving surface of the substrate 11 is reduced, and incident and reflection operations are performed at the texturing surface, so that light is trapped inside the solar cell, thereby increasing light absorption. do.

Thus, the efficiency of the solar cell is improved. In addition, the reflection loss of light incident on the substrate 11 is reduced, so that the amount of light incident on the substrate 11 is further increased.

The emitter portion 12 is a region doped with impurities having a second conductivity type that is opposite to the conductivity type of the substrate 11, for example, an n-type conductivity type, and includes the substrate 11 and pn. To form a junction.

When the emitter portion 12 has an n-type conductivity type, the emitter portion 12 may be doped with impurities of a pentavalent element such as phosphorus (P), arsenic (As), antimony (Sb), and the like on the substrate 11. Can be formed.

Accordingly, when electrons in the semiconductor receive energy by light incident on the substrate 11, the electrons move toward the n-type semiconductor and the holes move toward the p-type semiconductor. Therefore, when the substrate 11 is p-type and the emitter portion 12 is n-type, the separated holes move toward the substrate 11 and the separated electrons move toward the emitter portion 12.

In contrast, the substrate 11 may be of an n-type conductivity type, and may be made of a semiconductor material other than silicon. When the substrate 11 has an n-type conductivity type, the substrate 11 may contain impurities of pentavalent elements such as phosphorus (P), arsenic (As), and antimony (Sb).

Since the emitter 12 forms a p-n junction with the substrate 11, when the substrate 11 has an n-type conductivity type, the emitter 12 has a p-type conductivity type. In this case, the separated electrons move toward the substrate 11 and the separated holes move toward the emitter portion 12.

When the emitter portion 12 has a p-type conductivity type, the emitter portion 12 may dopant impurities of trivalent elements such as boron (B), gallium (Ga), indium (In), and the like onto the substrate 11. Can be formed.

On the emitter portion 12 of the substrate 11, an antireflection film 15 made of a silicon nitride film (SiNx), a silicon oxide film (SiO ₂ ), titanium dioxide (TiO ₂ ), or the like is formed. The anti-reflection film 15 reduces the reflectance of light incident on the solar cell 10 and increases the selectivity of a specific wavelength region to increase the efficiency of the solar cell 10. The anti-reflection film 15 may have a thickness of about 70 nm to 80 nm, and may be omitted as necessary.

The plurality of front electrodes 13 are formed on the emitter part 12 to be electrically and physically connected to the emitter part 12, and are formed in one direction in a state of being spaced apart from the adjacent front electrode 13. Each front electrode 13 collects charge, for example electrons, which have moved toward the emitter portion 12.

The plurality of front electrodes 13 include at least one conductive material, and the conductive materials include nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), and zinc (Zn). , At least one selected from the group consisting of indium (In), titanium (Ti), gold (Au), and combinations thereof, but may be formed of another conductive metal material.

For example, the front electrode 13 may be made of silver (Ag) paste containing lead (Pb). In this case, the front electrode 13 is coated with a silver paste on the anti-reflection film 15 using a screen printing process, and the emitter portion in the process of firing the substrate 11 at a temperature of about 750 ℃ to 800 ℃ And may be electrically connected to 12.

In this case, the above-described electrical connection is performed as the lead component included in the silver (Ag) paste etches the antireflection film 15 so that the silver particles come into contact with the emitter portion 12 during the firing process.

The front electrode current collector 14 is made of at least one conductive material and is electrically and physically connected to the emitter portion 12 and the front electrode 13. Therefore, the current collector 14 for the front electrode outputs the electric charge, for example, electrons transferred from the front electrode 13 to the external device.

The conductive metal materials constituting the front electrode current collector 14 include nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), indium (In), It may be at least one selected from the group consisting of titanium (Ti), gold (Au), and combinations thereof, but may be made of other conductive metal materials.

For example, the front electrode current collector 14 is coated with a conductive metal material on the anti-reflection film 15 and then patterned, similarly to the front electrode 13, by a punch through action in the process of firing the same. It may be electrically connected to the emitter portion 12. The rear electrode 16 is formed on the opposite side of the light receiving surface of the substrate 11, that is, on the rear surface of the substrate 11, and collects charges, for example, holes, moving toward the substrate 11.

The back electrode 16 is made of at least one conductive material. Conductive materials include nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), indium (In), titanium (Ti), gold (Au) and their It may be at least one selected from the group consisting of a combination, but may be made of other conductive materials.

A plurality of rear electrode current collectors 17 are positioned under the same plane or rear electrode 16 as the rear electrode 16. The rear electrode current collector 17 is formed in a direction crossing the front electrode 13, that is, in a direction parallel to the front electrode current collector 14.

The current collector 17 for the rear electrode is also made of at least one conductive material and is electrically connected to the rear electrode 16. Accordingly, the current collector 17 for the rear electrode outputs the electric charge, for example, holes, transferred from the rear electrode 16 to the external device.

The conductive metal materials constituting the current collector 17 for the rear electrode are nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), indium (In), It may be at least one selected from the group consisting of titanium (Ti), gold (Au), and combinations thereof, but may be made of other conductive metal materials.

The conductive adhesive film 60 is positioned on the front electrode current collector 14 and the rear electrode collector 17, and the interconnector 20 is positioned on the conductive adhesive film 60.

As shown in FIG. 3, the interconnector 20 is a lead-free conductive metal 22 containing lead content of 1,000 ppm or less, and flexible coated on the upper and lower surfaces of the metal 22, respectively. ) And a solder 24 of the material.

A plurality of irregularities 26 are formed on the upper surface of the interconnector 20, ie the upper surface of the solder 24 located on the upper surface of the conductive metal 22. These unevennesses 26 reflect light incident on the interconnector 20 and reenter the light to the light receiving surface of the solar cell.

As shown in FIG. 3, the irregularities 26 may be formed in a pyramid shape. At this time, the pyramidal irregularities 26 have four inclined surfaces, and the inclined surfaces facing each other may have an angle between 100 ° and 140 °.

If the angle between the inclined surfaces facing each other satisfies the above range, at least 20% or more of the light incident on the upper surface 23 of the interconnector 20 is totally reflected at the inclined surface of the unevenness 26, and then the antireflection film 15 Will be re-entered. Therefore, the light absorption rate on the light receiving surface is effectively increased.

Meanwhile, the unevenness 26 may be formed to maintain an aspect ratio (thickness / width) of 1 to 2.

Although FIG. 3 illustrates that the size of each unevenness 26 is uniform, the unevenness 26 may be formed in non-uniform size with each other. Here, since it is easy for those skilled in the art to form the irregularities 26 in non-uniform sizes, no separate drawings are attached.

In addition, although the distribution of each unevenness 26 is uniform in FIG. 3, the unevenness 26 may be distributed in a non-uniform distribution, and may be distributed in an island type.

As such, the unevenness 26 located on the upper surface of the interconnector 20, ie the upper surface of the conductive metal 22, may have a uniform or non-uniform size, and may be uniform or non-uniformly distributed.

Meanwhile, the unevenness 26 positioned on the upper surface of the solder 24 may be formed in a linear prism shape having a uniform size. In this case, the irregularities of the linear prism shape may include two inclined surfaces, and the inclined surfaces may have an angle between 100 ° and 140 °.

When the angles of the inclined surfaces facing each other satisfy the above range, at least 20% or more of the light incident on the interconnector 20 is totally reflected on the inclined surface of the unevenness, and then is reincident to the antireflection film 15.

The unevenness of the linear prism shape having a uniform size may be distributed in a nonuniform distribution such as an island shape, or may be formed in a nonuniform size similarly to the above-described pyramidal unevenness 26.

When the irregularities of the linear prism shape are formed to have a non-uniform size, the irregularities increase in the width of the unevenness toward the widthwise end portion from the widthwise center portion of the interconnector 20, or the unevenness of the unevenness toward the center portion from the widthwise edge portion thereof. It may be formed in the form of increasing thickness.

The unevenness 26 positioned on the upper surface of the interconnector 20 may be formed in a diagonal prism shape having a uniform size, or may be formed in a groove having a cross-sectional shape of a semicircle or a semi-ellipse.

As such, irregularities of various shapes, cross sections, widths, and thicknesses may be formed in various patterns on the upper surface of the interconnector 20.

In addition, the interconnector 20 may be made of only the conductive metal 22. In this case, the unevenness 26 may be formed on the upper surface of the conductive metal 22. It is also possible for the unevenness 26 to be formed on both the top and bottom surfaces of the interconnector 20.

The solder 24 includes at least one material selected from metal materials such as bismuth (Bi), tin (Sn), lead (Pb), silver (Ag), zinc (Zn), and copper (Cu). However, the solder 24 made of such a metal material is melted at a temperature of about 180 ° C. or more as shown in FIG. 4. 4 shows the melting temperature according to the material of the solder 24.

As such, since the solder 24 is melted at a high temperature of 180 ° C. or higher depending on the material, when tabbing is performed by a soldering operation using flux, a process temperature higher than the melting temperature of the solder 24 should be used. As a result, the surface shape of the unevenness 26 formed on the upper surface of the solder 24 is damaged.

In addition, damage due to bending of the substrate occurs due to a high process temperature, and micro cracks, over soldering, or misalignment may occur due to flux use.

In order to prevent such a problem, in the present embodiment, the tabbing operation can be performed at a melting temperature of the solder 24 below, for example, 140 ° C to 200 ° C.

To this end, the present embodiment uses a conductive adhesive film 60 capable of tabbing at low temperatures (140 ° C. to 200 ° C.) instead of tabbing in a soldering operation using flux.

3 illustrates only one conductive adhesive film 60 on the front and rear surfaces of the substrate 11, but two to three conductive adhesive films 60 may be positioned on the front and rear surfaces of the substrate 11. have.

As shown in FIG. 5, the conductive adhesive film 60 includes a resin 62 and conductive particles 64 and a conductive filler 66 dispersed in the resin 62.

The resin 62 is an adhesive material and is not particularly limited as long as the resin 62 is melted at or below the melting temperature of the solder 24. 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.

In this case, the front electrode current collector 14 and the rear electrode current collector 17 to which the conductive adhesive film 60 is bonded may include a resin having the same material as the resin 62 as a binder.

Resin 62 may contain a known curing agent and a curing accelerator as optional components other than the thermosetting resin.

For example, the resin 62 is made of a silane coupling agent to improve adhesion between the front electrode current collector 14 and the rear electrode current collector 17 and the interconnector 20. , And a modifying material such as a titanate coupling agent and an aluminate coupling agent, and may contain calcium phosphate or carbonic acid to improve the dispersibility of the conductive particles 64 and the conductive filler 66. Dispersing agents such as calcium. In addition, the resin 62 may contain rubber components such as acrylic rubber, silicone rubber, urethane, and the like to control the elastic modulus.

The conductive particles 64 directly contact the current collector 14 and the interconnector 20 for the front electrode and the current collector 17 and the interconnector 20 for the rear electrode to enable electrical connection in the vertical direction. If it has electroconductivity, the material will not be specifically limited.

The conductive particles 64 include copper (Cu), silver (Ag), gold (Au), iron (Fe), nickel (Ni), lead (Pb), zinc (Zn), cobalt (Co), titanium (Ti) And at least one metal selected from magnesium (Mg) as a main component, and may be made of only metal particles or metal coating resin particles.

In order to relieve the compressive stress of the electroconductive particle 64 and to improve connection reliability, it is preferable to use metal coating resin particles as the electroconductive particle 64.

In order to improve dispersibility, it is preferable that the electroconductive particle 64 has a particle diameter of 2 micrometers-30 micrometers.

In view of the connection reliability after the resin 62 is cured, the compounding amount of the conductive particles 64 dispersed in the resin 62 is contained in the resin 62 in an amount of 10 vol% to 40 vol% with respect to the resin 62. It is preferred to be dispersed.

If the compounding amount of the conductive particles 64 is less than 10% by volume, the physical contact with the current collectors 14 and 17 is reduced, so that the current may not flow smoothly. If the compounding amount exceeds 40% by volume, the resin 62 The relative amount of c) may decrease and the adhesive strength may decrease.

The conductive filler 66 is intended to enable electrical connection in the horizontal direction. The conductive material has an aspect ratio of 2 or more, such as graphene, carbon nanotubes, and metallic nanowires. ), Metal wire, and metal particles.

Here, the aspect ratio refers to the ratio (length / width) of the length to the width (or thickness), and the length and width of the conductive filler 66 are not particularly limited.

In terms of the electrical connection between the conductive particles 64, the compounding amount of the conductive filler 66 dispersed in the resin 62 is preferably included 0.01 wt% or more based on the total weight of the conductive adhesive film 60, because the conductive If the compounding amount of the particles 64 is less than 0.01% by weight, the electrical connection between the conductive particles 64 may not be good.

For electrical connection between the conductive particles 64, at least a portion of the conductive filler 66 is located in the space between the conductive particles 64, and also in a direction that is not parallel to the thickness direction of the conductive adhesive film 60, that is, It is located in a direction that is not perpendicular to the current collector 14 for the front electrode, the current collector 17 for the rear electrode, and the interconnector 20.

One end of the conductive filler 66 may be in contact with the front electrode current collector 14, the rear electrode current collector 17, or the interconnector 20.

According to this structure, the electrical connection between the adjacent conductive particles 64 is made by the conductive filler 66, and the electrical connection between the current collectors 14 and 17 and the interconnector 20 is the conductive particles 64. And the conductive filler 66.

The conductive adhesive film 60 of this configuration may further include a cover film.

When the tabbing operation is completed, the front electrode current collector 14 and the interconnector 20 are conductive so that the flat lower surface of the interconnector 20 faces the front electrode current collector 14 as shown in FIG. 6. The top surface of the interconnector 20, that is, the surface on which the unevenness 26 is formed, is adhered by the adhesive film 60, and the back electrode current collector 17 and the interconnector 20 are formed on the back electrode current collector 17. ) Is bonded by the conductive adhesive film 20 so as to face.

At this time, the tabbing operation is made by a conductive adhesive film 60 capable of a low temperature process.

Thus, the concave-convex 26 located on the upper surface of the interconnector 20 in the area bonded to the current collector 14 for the front electrode maintains a good surface shape.

In addition, the concave-convex 26 positioned on the upper surface of the interconnector 20 in the region bonded to the current collector 17 for the rear electrode also maintains a good surface shape, and the conductive adhesive film 60 is formed in the space between the concave-convex 26. A part of), for example, is filled with the resin 62 or the resin 62 and the conductive particles 64 and the conductive filler 66.

On the other hand, the conductive particles 64 may be in direct contact with at least one of the current collector 14 for the front electrode and the interconnector 20, or may be in direct contact with both. Likewise, at least one of the rear electrode current collector 17 and the interconnector 20 may be in direct contact or both.

In this case, the conductive particles 64 may be deformed into an ellipse due to the pressure applied during the tabbing operation.

According to this structure, electric charges transferred to the current collector 14 for the front electrode and the current collector 17 for the rear electrode are transferred directly to the interconnector 20 through the conductive particles 64, so that the current flows smoothly.

In addition, since the conductive filler 66 positioned between the conductive particles 64 makes electrical connections between the adjacent conductive particles 64, the charges transferred to the current collectors 14 and 17 are more effectively interconnected 20. Go to).

In the above description, a plurality of unevennesses are formed on the upper surface of the interconnector 20 as an example, but it is also possible to use a common one in which both surfaces of the interconnector 20 are flat.

In addition, the widths of the interconnector 20, the conductive adhesive film 60, and the current collectors 14 and 17 may be variously changed within an appropriate range.

Hereinafter, a method of manufacturing a solar cell panel according to an embodiment of the present invention will be described with reference to FIG. 7.

The manufacturing method of this embodiment is largely a temporary pressing step of pressing the conductive adhesive film 60 to the current collectors 14 and 17, and aligning the interconnector 20 with the conductive adhesive film 60. And an alignment and provision fixing step for temporarily fixing, and a main compression step for bonding the interconnector 20, the conductive adhesive film 60, and the current collectors 14 and 17 together. It includes.

At this time, an important feature of the present manufacturing method is that the resin 62 of the conductive adhesive film 60 is melted by pressing the interconnector with a heating tool in the main pressing step.

As shown in FIG. 4, the solder 24 has a melting temperature that is different depending on the material, but has a melting temperature of about 180 ° C. or more.

Therefore, in the manufacturing method of the present embodiment, the main pressing process is performed using a heating tool 70 heated at a temperature of 140 ° C. to 200 ° C. according to the material of the solder 24.

Specifically, the temporary pressing step refers to a step of primarily pressing the current collectors 14 and 17 in a state in which the conductive adhesive film 60 is aligned, and having a temperature of 60 ° C. to 120 ° C. Pressing the heating tool (heating tool) 70 heated to a pressure of 0.5 MPa to 1.5 MPa for 1 second to 10 seconds.

The alignment and temporary fixing step may further include removing a cover film (not shown) located on the upper surface of the conductive adhesive film 60 that is temporarily fixed to the current collectors 14 and 17. Can be.

And the main pressing step may include pressing the heating tool (70 ') heated to a temperature of 140 ℃ to 200 ℃ for 5 seconds to 15 seconds at a pressure of 1.0 MPa to 5.0 MPa. .

When the solar cell panel is manufactured according to this method, since the surface shape of the unevenness 26 formed on the upper surface of the interconnector 20 can be maintained well, the light incident on the interconnector 20 can be used for power generation. .

Since tabbing is carried out in a low temperature process, bowing and damage to the substrate can be prevented as compared with the case of performing tabbing by soldering.

In addition, since adjacent conductive particles are electrically connected by the conductive filler, the output of the solar cell can be improved.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

10: solar cell 11: substrate
12: emitter part 13: front electrode
14: current collector for front electrode 15: antireflection film
16: rear electrode 17: current collector for rear electrode
20: interconnector 30a, 30b: protective film
40: transparent member 50: back sheet
60: conductive adhesive film 62: resin
64: conductive particles 66: conductive filler

Claims

A conductive adhesive film positioned between two electrode portions and electrically connecting the two electrode portions,
Resin having adhesiveness;
A plurality of conductive particles dispersed in the resin and electrically connecting the two electrode parts; And
A plurality of conductive fillers dispersed in the resin and electrically connecting the adjacent conductive particles
Conductive adhesive film comprising a.

In claim 1,
The conductive filler is included in the conductive adhesive film 0.01% by weight or more based on the total weight of the conductive adhesive film.

In claim 1,
The conductive filler has a conductive adhesive film having an aspect ratio of two or more.

4. The method of claim 3,
The conductive filler may include at least one selected from graphene, carbon nanotubes, metallic nanowires, metal wires, and metal particles. .

The method according to any one of claims 1 to 4,
At least a part of the conductive filler is a conductive adhesive film located in the space between the conductive particles.

The method of claim 5,
At least a portion of the conductive filler is located in a direction that is not parallel to the thickness direction of the resin.

The method of claim 5,
At least a part of the conductive filler is in contact with the conductive particles conductive adhesive film.

A plurality of solar cells including a substrate, and a plurality of electrode portions positioned on a surface of the substrate;
An interconnector for electrically connecting electrode portions of adjacent solar cells; And
A conductive adhesive film comprising a resin and a plurality of conductive particles dispersed in the resin, and is compressed between the electrode portion and the interconnector to electrically connect the electrode portion and the interconnector.
Including;
The conductive adhesive film further includes a conductive filler dispersed in the resin.

9. The method of claim 8,
The conductive filler is a solar cell panel containing 0.01% by weight or more based on the total weight of the conductive adhesive film.

9. The method of claim 8,
The conductive filler has a solar cell panel having an aspect ratio of two or more.

11. The method of claim 10,
The conductive filler includes at least one selected from graphene, carbon nanotubes, metallic nanowires, metal wires, and metal particles. .

11. The method of claim 10,
At least a portion of the conductive filler is located in the space between the conductive particles.

11. The method of claim 10,
At least a portion of the conductive filler contacts the electrode portion, the interconnector, or the conductive particles.

11. The method of claim 10,
At least a portion of the conductive filler is located in a direction that is not perpendicular to the electrode portion and the interconnector.

The method according to any one of claims 8 to 14,
The electrode unit includes a front electrode located on the front of the substrate and a rear electrode located on the rear of the substrate.

The method of claim 15,
The front electrode unit includes a plurality of front electrodes and a plurality of front electrode current collectors positioned in a direction crossing the front electrodes.

The method of claim 16,
The front electrode and the front electrode current collector portion is connected to the emitter unit located on the front of the substrate solar cell panel.

The method of claim 16,
The rear electrode part includes a rear electrode and a rear electrode current collector disposed on a rear surface of the substrate, and the rear electrode current collector is positioned in a direction parallel to the current collector for the front electrode.

A method of manufacturing a solar cell panel for electrically connecting a plurality of solar cells including a plurality of electrode portions positioned on a surface of a substrate,
A temporary pressing step of temporarily pressing a conductive adhesive film comprising a resin and a plurality of conductive particles and a plurality of conductive fillers dispersed in the resin;
An alignment and provision fixing step of aligning and provisionally fixing an interconnector to the pressed conductive adhesive film; And
A main crimping step of compressing the interconnector and the conductive adhesive film such that the electrode portion and the interconnector are electrically connected by the conductive adhesive film.
Including;
The main pressing step may include pressing the interconnector with a heating tool to melt the resin of the conductive adhesive film.

The method of claim 19,
The main pressing step may include pressurizing the interconnector for 5 seconds to 15 seconds at a pressure of 1.0 MPa to 5.0 MPa using the heating tool heated to a temperature of 140 ° C. to 200 ° C. .

The method of claim 19,
The pressing step is a solar cell panel comprising pressing the conductive adhesive film for 1 second to 10 seconds at a pressure of 0.5 MPa to 1.5 MPa using a heating tool heated to a temperature of 60 ℃ to 120 ℃ Method of preparation.