HK1185451A - Conductive adhesive material, solar cell module, and method for manufacturing same - Google Patents

Description

Conductive adhesive material, solar cell module, and method for manufacturing same

Technical Field

The present invention relates to a conductive adhesive material in which conductive particles are dispersed, a solar cell module in which a front/rear surface electrode of a solar cell is connected to a tab wire (タブ) using the conductive adhesive material, and a method for manufacturing the solar cell module. This application is based on Japanese patent application No. 2010-263607 filed on 26/2010 in Japan, the priority of which is claimed and incorporated herein by reference.

Background

Conventionally, in a crystalline silicon-based solar cell module, a plurality of adjacent solar cells are connected by tab wires made of a copper foil strip coated with solder (ハンダ). The tab wire connects one end side to the front surface electrode of one solar battery cell and the other end side to the rear surface electrode of another adjacent solar battery cell, thereby connecting the solar battery cells in series.

Specifically, the connection between the solar cell and the tab wire is performed by connecting a bus bar electrode (バスバー computer) formed on the light receiving surface of the solar cell and an Ag electrode formed on the rear surface connection portion of the solar cell to the tab wire through a soldering process by screen printing using silver paste. In addition, Al electrodes may be formed in regions other than the connection portions on the back surface of the solar cell.

However, since the connection process is performed at a high temperature exceeding 200 ℃ during soldering, the connection reliability between the surface electrode and the tab wire of the solar cell and between the back surface electrode and the tab wire may be reduced due to warpage of the solar cell, internal stress generated at the connection portions of the tab wire and the surface electrode and the back surface electrode, and further, due to the residue of the flux.

Therefore, it has been proposed to use a conductive adhesive film that can be connected by thermocompression bonding at a relatively low temperature for connecting the front and rear electrodes of the solar cell to the tab wire (see, for example, patent documents 1 and 2).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2007-214533

Patent document 2: japanese patent laid-open No. 2008-135652.

Disclosure of Invention

Technical problem to be solved by the invention

However, the conventional conductive adhesive film for a solar cell module uses a metal filler as conductive particles, and does not form a metal bond with an electrode as in soldering, so that there is a concern about connection reliability.

The present invention has been made in view of the above conventional facts, and provides a conductive adhesive material capable of obtaining high connection reliability, a method for producing the conductive adhesive material, a solar cell module, and a method for producing the solar cell module.

Means for solving the technical problem

As a result of intensive studies, the present inventors have found that high connection reliability can be obtained by using solder particles as conductive particles of a conductive adhesive material and using an acid anhydride-based curing agent or a phenol-based curing agent as a curing agent.

That is, the conductive adhesive material according to the present invention is characterized by containing a film-forming resin, a liquid epoxy resin, a curing agent and conductive particles, wherein the curing agent is an acid anhydride-based curing agent or a phenol-based curing agent, and the conductive particles are solder particles.

The solar cell module according to the present invention is a solar cell module in which a front surface electrode of one solar cell and a rear surface electrode of another solar cell adjacent to the one solar cell are electrically connected to each other by a tab wire through a conductive adhesive material, wherein the conductive adhesive material contains a forming resin, a liquid epoxy resin, a curing agent and conductive particles, the curing agent is an acid anhydride-based curing agent or a phenol-based curing agent, and the conductive particles are solder particles.

A method for manufacturing a solar cell module according to the present invention is a method for manufacturing a solar cell module in which a front surface electrode of one solar cell and a back surface electrode of another solar cell adjacent to the one solar cell are electrically connected to each other by a conductive adhesive material through a tab wire, the conductive adhesive material containing a forming resin, a liquid epoxy resin, a curing agent and conductive particles, the curing agent being an acid anhydride-based curing agent or a phenol-based curing agent, the conductive particles being solder particles, the method including the steps of: a temporary arrangement step of temporarily arranging the front surface electrode and the tab wire of the one solar cell and the rear surface electrode and the tab wire of the other solar cell with the conductive adhesive material therebetween; and a pressing step of pressing the upper surface of the tab wire with a heating pressing head.

A method for manufacturing a solar cell module according to the present invention is a method for manufacturing a solar cell module in which a front surface electrode of one solar cell and a back surface electrode of another solar cell adjacent to the one solar cell are electrically connected to each other by a conductive adhesive material through a tab wire, the conductive adhesive material containing a forming resin, a liquid epoxy resin, a curing agent and conductive particles, the curing agent being an acid anhydride-based curing agent or a phenol-based curing agent, the conductive particles being solder particles, the method including the steps of: a temporary arrangement step of temporarily arranging the front surface electrode and the tab wire of the one solar cell and the rear surface electrode and the tab wire of the other solar cell with the conductive adhesive material therebetween; and a laminating and pressure-bonding step of laminating a sealing material and a protective base material in this order on the upper and lower surfaces of the solar cell, laminating and pressure-bonding the sealing material by a laminating device from the upper surface of the protective base material, and connecting the front surface electrode and the tab wire and the rear surface electrode and the tab wire while curing the sealing material.

Effects of the invention

According to the present invention, solder particles are used as conductive particles of a conductive adhesive material, and an acid anhydride-based curing agent or a phenol-based curing agent is used as a curing agent, whereby solder wettability can be improved, a strong metal bond can be formed, and high connection reliability can be obtained.

Drawings

Fig. 1 is an exploded perspective view of a solar cell module to which the present invention is applied.

Fig. 2 is a sectional view of the solar cell module shown in fig. 2.

FIG. 3 is a sectional view showing the structure of a vacuum laminator.

Detailed Description

The embodiments of the present invention will be described in detail below in the following order with reference to the drawings.

1. Conductive adhesive material

2. Solar cell module

3. Method for manufacturing solar cell module

4. Examples of the embodiments

< 1. conductive adhesive Material

First, a conductive adhesive material for electrically connecting the front surface electrode or the rear surface electrode of the solar battery cell to the tab wire will be described. The shape of the conductive adhesive material is not limited to the film shape, and may be paste.

The conductive adhesive material in the present embodiment contains a film-forming resin, a liquid epoxy resin, a curing agent, and conductive particles, and an acid anhydride-based curing agent or a phenol-based curing agent is used as the curing agent, and solder particles are used as the conductive particles.

The film-forming resin corresponds to a high molecular weight resin having an average molecular weight of 10000 or more, and preferably has an average molecular weight of approximately 10000 to 80000 from the viewpoint of film-forming properties. As the film-forming resin, various resins such as an epoxy resin, a modified epoxy resin, a urethane resin, and a phenoxy resin can be used, and among them, a phenoxy resin is preferably used from the viewpoint of the film-forming state, connection reliability, and the like.

The liquid epoxy resin is not particularly limited as long as it has fluidity at room temperature, and commercially available epoxy resins can be used in all. Specific examples of the epoxy resin include naphthalene type epoxy resins, biphenyl type epoxy resins, phenol novolac type epoxy resins, bisphenol type epoxy resins, stilbene type epoxy resins, triphenol methane type epoxy resins, phenol aralkyl type epoxy resins, naphthol type epoxy resins, dicyclopentadiene type epoxy resins, and triphenylmethane type epoxy resins. They may be used alone or in combination of 2 or more. In addition, the resin composition may be used in appropriate combination with other organic resins such as acrylic resin.

As the curing agent, an acid anhydride-based curing agent or a phenol-based curing agent is used. These curing agents have a flux effect of improving solder wettability and react with an epoxy component during curing, so that adverse effects due to the residue of the curing agent can be prevented.

As the acid anhydride curing agent, alicyclic acid anhydride, aromatic acid anhydride, aliphatic acid anhydride, or the like can be used. Among them, alicyclic acid anhydrides having a norbornene skeleton are preferably used. Examples of such alicyclic acid anhydrides include methylbicyclo [2.2.1] heptane-2.3-dicarboxylic anhydride/bicyclo [2.2.1] heptane-2.3-dicarboxylic anhydride represented by the following general formula.

[ chemical formula 1]

(wherein R represents hydrogen or methyl.)

Further, a curing agent having a free carboxylic acid is not preferable because it has high reactivity and reduces the life of the conductive adhesive material.

As the phenol curing agent, a phenol formaldehyde type phenol resin, a phenol aralkyl type phenol resin, or the like can be used.

As the conductive particles, eutectic solder capable of being connected by thermocompression bonding at a relatively low temperature, and solder particles such as low melting point solder to which Bi and In are added are preferably used. The melting point of the solder particles may be appropriately set according to the starting temperature of the curing agent, but is preferably 100 ℃ to 200 ℃, and more preferably 135 ℃ to 150 ℃ from the viewpoint of warpage of the solar battery cell and internal stress generated at the connection portion between the tab wire and the front and rear surface electrodes.

In the relationship between the solder particles and the curing agent, the curing start temperature of the curing agent is preferably not lower than the melting point of the solder particles. Thus, after sufficient bending performance of the curing agent is exhibited, the curing agent and the epoxy can be cured. The present invention can be preferably used in a lamination and pressure bonding step in which the sealing resin is cured and the electrode and the tab wire are connected at the same time, which will be described later.

The absolute value of the difference between the solidification start temperature of the solidifying agent and the melting point of the solder particles is preferably 35 ℃ or less, and more preferably 15 ℃ or less. If the temperature difference is larger than this, the soldering effect is insufficient and the connection reliability is lowered.

As another additive composition, rubber-based elastic particles such as acrylic rubber (ACR), Butadiene Rubber (BR), and nitrile rubber (NBR) are preferably blended. The elastic particles can absorb internal stress and can provide high connection reliability because they do not cause curing inhibition.

Further, a silane coupling agent may be added. As the silane coupling agent, epoxy, amino, mercapto-sulfide, ureide, or the like can be used. This improves the adhesion at the interface between the organic material and the inorganic material.

By using the conductive adhesive material, a firm metal bond can be formed between the tab wire and the electrode by a low-temperature thermocompression bonding process, and high connection reliability can be obtained.

In the case of producing the conductive adhesive material having the above-described configuration, the forming resin, the liquid epoxy resin, the curing agent, and the conductive particles are dissolved in a solvent. As the solvent, toluene, ethyl acetate, or the like, or a mixed solvent thereof can be used.

In the case of producing a sheet-shaped conductive film, a resin composition in which a resin, a liquid epoxy resin, a curing agent, and conductive particles are dissolved in a solvent is applied to a release substrate using a bar coater, a coating device, or the like, and the composition on the release substrate is dried using a heat oven, a heat drying device, or the like, thereby obtaining a conductive film having a predetermined thickness.

The release substrate has a laminated structure in which a release agent such as silicone is applied to PET (polyethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methyl-1-pentene Poly-4-methyl-pentane-1), PTFE (Polytetrafluoroethylene), or the like, and can maintain the shape of the conductive film while preventing the conductive film from drying.

< 2. solar cell Module >

Hereinafter, a solar cell module to which the present invention is applied and a method for manufacturing the same will be described in detail with reference to the drawings. The solar cell module 1 to which the present invention is applied is a crystalline silicon solar cell module using a single crystal silicon photoelectric conversion element or a polycrystalline silicon photoelectric conversion element as a photoelectric conversion element; or a thin-film silicon solar cell using a photoelectric conversion element in which a cell made of amorphous silicon and a cell made of microcrystalline silicon or amorphous silicon germanium are stacked.

As shown in fig. 1, the solar cell module 1 includes a wire (ストリングス) 4 connecting a plurality of solar cells 2 in series via a tab wire 3 connected to the inside thereof, and a base (マトリクス) 5 on which the plurality of wires 4 are arranged. Further, the solar cell module 1 is formed by the following method: this base body 5 is sandwiched by a sheet 6 of sealing adhesive, a front cover 7 provided on the light receiving surface side and a back plate 8 provided on the back surface side are simultaneously laminated as a protective base, and finally a metal frame 9 of aluminum or the like is attached around the periphery.

As the sealing adhesive, for example, a light-transmitting sealing material such as ethylene vinyl alcohol resin (EVA) is used. As the surface cover 7, for example, a light-transmitting material such as glass or light-transmitting plastic is used. As the back sheet 8, a laminate or the like in which glass or aluminum foil is sandwiched by resin films is used.

As shown in fig. 2, each solar cell 2 of the solar cell module has a photoelectric conversion element 10 made of a silicon substrate. The photoelectric conversion element 10 is provided with a bus bar electrode 11 serving as a surface electrode and a finger electrode 12 serving as a collector electrode formed in a direction substantially perpendicular to the bus bar electrode 11 on the light receiving surface side. The photoelectric conversion element 10 is provided with an Al rear surface electrode 13 made of aluminum on the rear surface side opposite to the light receiving surface.

Further, the solar battery cells 2 are connected electrically between the bus bar electrode 11 on the front surface and the Al rear surface electrode 13 of the adjacent solar battery cell 2 via the tab wire 3, thereby forming a series-connected wire 4. The tab wire 3 is connected to the bus bar electrode 11 and the Al rear surface electrode 13 via the conductive adhesive film 20.

The tab wire 3 may utilize a tab wire used in an existing solar cell module. The tab wire 3 is formed by using a strip-shaped copper foil having a thickness of 50 to 300 μm, and performing gold plating, silver plating, tin plating, plating soldering, and the like as necessary. Alternatively, a conductive adhesive film may be laminated on the tab wire 3 in advance.

The bus bar electrode 11 is formed by applying Ag paste and heating. The bus bar electrodes 11 formed on the light receiving surface of the solar battery cell 2 are formed in a linear shape with a width of, for example, 1mm in order to reduce the area for blocking incident light and to suppress the shielding loss (シャドーロス). The number of bus bar electrodes 11 is appropriately set in consideration of the size and resistance of the solar battery cell 2.

The finger electrodes 12 are formed on substantially the entire light-receiving surface of the solar cell 2 so as to intersect the bus bar electrodes 11 in the same manner as the bus bar electrodes 11. The finger electrodes 12 are formed with lines having a width of, for example, about 100 μm at predetermined intervals, for example, 2mm intervals.

The Al rear surface electrode 13 may be formed of an electrode made of aluminum on the rear surface of the solar cell 2 by, for example, screen printing, sputtering, or the like.

In addition, the solar battery cell 2 does not necessarily have to be provided with the bus bar electrode 11. At this time, the solar cell 2 concentrates the current of the finger electrodes 12 through the tab line 3 crossing the finger electrodes 12. Further, the Al rear surface electrode 13 may be formed with an opening to such an extent that a connection failure with the tab wire does not occur, whereby the adhesion strength can be secured.

< 3. method for manufacturing solar cell module

Next, a method for manufacturing a solar cell module will be described with reference to fig. 1. A method for manufacturing a solar cell module according to embodiment 1 is a method for manufacturing a solar cell module in which a front surface electrode of one solar cell and a rear surface electrode of another solar cell adjacent to the one solar cell are electrically connected to each other by a tab wire through a conductive adhesive material, wherein the front surface electrode of the one solar cell and the tab wire, and the rear surface electrode of the another solar cell and the tab wire are temporarily arranged through the conductive adhesive film, and are pressed by a heating pressing head from the upper surface of the tab wire.

Specifically, first, finger electrodes 12 and bus bar electrodes 11 are formed on the surface of the photoelectric conversion element 10 by applying Ag paste and firing, and an Al rear surface electrode 13 is formed on the connection portion of the tab wire 3 on the rear surface by Al screen printing or the like to fabricate a solar cell.

Next, the conductive adhesive film 20 is attached to the bus bar electrode 11 on the front surface and the Al rear surface electrode 13 on the rear surface of the photoelectric conversion element 10, and the tab wire 3 is arranged on the conductive adhesive film 20.

Further, the tab wire 3 is electrically connected to the bus bar electrode 11 and the Al rear surface electrode 13 by being heated and pressed at a predetermined pressure from above the tab wire 3. At this time, the tab wire 3 is mechanically and strongly connected to the bus bar electrode 11 because the binder resin of the conductive adhesive film 20 has good adhesiveness to the bus bar electrode 11 formed of Ag paste. In addition, the tab wire 3 is electrically connected to the Al rear surface electrode 13.

The solar cell module 1 is manufactured by sandwiching the base 5 to which the solar cells 2 are connected with a sheet 6 of sealing adhesive, and simultaneously laminating a front cover 7 provided on the light receiving surface side and a back sheet 8 provided on the back surface side as a protective material.

In embodiment 1, the conductive adhesive film contains a forming resin, a liquid epoxy resin, a curing agent and conductive particles, the curing agent is an acid anhydride-based curing agent or a phenol-based curing agent, and the conductive particles are solder particles, so that when pressed by a heating and pressing head, a strong metallic bond can be formed between the tab wire and the electrode by a thermocompression bonding process at a relatively low temperature of 200 ℃.

Next, a method for manufacturing a solar cell module according to embodiment 2 in which curing of a sealing resin and connection of an electrode and a tab wire are simultaneously performed will be described. A method for manufacturing a solar cell module according to embodiment 2 is a method for manufacturing a solar cell module in which a front surface electrode of one solar cell and a back surface electrode of another solar cell adjacent to the one solar cell are electrically connected to each other through a conductive adhesive film by a tab wire, wherein the front surface electrode of the one solar cell and the tab wire, and the back surface electrode of the other solar cell and the tab wire are temporarily fixed to each other through the conductive adhesive film, a sealing material and a protective substrate are stacked in this order on the upper and lower surfaces of the solar cell, the top surface of the protective substrate is stacked and pressed by a stacking device, and the front surface electrode, the tab wire, and the back surface electrode are connected to the tab wire while the sealing material is cured.

First, a laminating apparatus that simultaneously cures a sealing resin and connects an electrode and a tab wire will be described.

Fig. 3 is a view showing a structure of a decompression laminator. The decompression laminator 30 is composed of an upper unit 31 and a lower unit 32. These units are integrated by a sealing member 33 such as an O-ring so as to be separable. A flexible sheet 34 such as silicone rubber is provided on the upper unit 31, and the decompression stacking machine 30 is divided into a 1 st chamber 35 and a 2 nd chamber 36 by the flexible sheet 34.

Further, the upper unit 31 and the lower unit 32 are provided with pipes 37 and 38, respectively, so that the internal pressure of each chamber can be independently adjusted, i.e., the pressure can be reduced or increased by a vacuum pump, a compressor, or the like, and the atmosphere can be opened. The pipe 37 is branched into 2 directions of the pipes 37a and 37b by the switching valve 39, and the pipe 38 is branched into 2 directions of the pipes 38a and 38b by the switching valve 40. In addition, a heatable platform 41 is provided on the lower unit 32.

Next, a specific connection method using the reduced-pressure laminator 30 will be described. First, the upper unit 31 and the lower unit 32 are separated, and a laminate of a sealing material and a protective base material (the surface cover 7 and the back sheet 8) is placed on the stage 41 in this order on the upper and lower surfaces of the solar battery cell to which the tab wire is temporarily fixed. The temperature at which the tab wire is temporarily fixed to the solar cell may be lower than the melting point of the solder particles of the conductive adhesive material.

Further, the upper unit 31 and the lower unit 32 are separably integrated by the seal member 33, and then a vacuum pump is connected to the pipe 37a and the pipe 38a, respectively, to make the 1 st chamber 35 and the 2 nd chamber 36 have a high vacuum. The inside of the 2 nd chamber 36 is kept in a high vacuum state, the switching valve 39 is switched, and the atmosphere is introduced into the 1 st chamber 35 through the pipe 37 b. As a result, the flexible sheet 34 expands toward the 2 nd chamber 36, and as a result, the laminate is heated on the stage 41 and pressed by the flexible sheet 34.

After thermocompression bonding, the switching valve 40 is switched, and the atmosphere is introduced into the 2 nd chamber 36 through the pipe 38 b. Thereby, the flexible sheet 34 is pushed back toward the 1 st chamber 35, and finally, the internal pressures of the 1 st chamber 35 and the 2 nd chamber 36 become the same.

Finally, the upper unit 31 and the lower unit 32 are separated, and the solar cell module subjected to the thermal compression bonding process is taken out from the stage 41. Thereby, the curing of the sealing resin and the connection of the electrode and the tab wire can be performed simultaneously.

In embodiment 2, the thermocompression bonding temperature of the laminating device is set to be higher than the melting point of the solder particles of the conductive adhesive material, so that a strong metal bond can be formed between the tab wire and the electrode, and high connection reliability can be obtained. Further, by using a conductive adhesive material in which the curing start temperature of the curing agent is not lower than the melting point of the solder particles, the curing agent and the epoxy can be cured after the sufficient bending function of the curing agent is exhibited. Further, by using a conductive adhesive material in which the difference between the curing start temperature of the curing agent and the melting point of the solder particles is 15 ℃ or less, a sufficient flux effect can be obtained and the connection reliability can be improved.

[ examples ]

< 4. example >

Examples of the present invention will be described below, but the present invention is not limited to these examples. Here, as in examples 1 to 6 and comparative examples 1 to 3 described below, the front and back surface electrodes of the solar battery cells were connected to tab wires using a conductive adhesive film, and the bondability, adhesiveness, and connection reliability were evaluated.

[ evaluation of binding Properties ]

As an evaluation of the flux function, the electrodes and tab wires of the solar cell were peeled off, and the wettability of the solder was observed using an optical microscope. In the evaluations shown in tables 1 and 2, the wettability was evaluated as excellent when the original area showed an area ratio of 3.0 times or more, as good as the original area when the original area showed an area ratio of 1.5 times or more and less than 3.0 times, as Δ when the original area showed an area ratio of less than 1.5 times, and as x when the original area showed no wettability.

[ evaluation of adhesiveness ]

The tab wire of the solar cell was pulled up to 90 ° with respect to the electrode surface using a tensile tester (manufactured by テンシオロン, オリエンテック), and the adhesion strength was measured. In the evaluations shown in tables 1 and 2, the case where the adhesion strength was 2.0N/mm or more was evaluated as "excellent", the case where the adhesion strength was 1.5N/mm or more and less than 2.0N/mm was evaluated as "good", the case where the adhesion strength was 1.0N/mm or more and less than 1.5N/mm was evaluated as "large", and the case where the adhesion strength was less than 1.0N/mm was evaluated as "x".

[ evaluation of connection reliability ]

Measuring the Initial (Initial) resistance of the solar cell; and the resistance after TH Test (Thermal Humidity Test) at a temperature of 85 ℃ and a Humidity of 85% RH for 500 hours. The connection resistance was measured by a 4-terminal network method (4-terminal method) using a digital multimeter (digital multimeter 7555, manufactured by yokogawa electric corporation) when a current of 1mA was passed. In the evaluations shown in tables 1 and 2, the case where the connection resistance was less than 4 Ω was evaluated as "excellent", the case where the connection resistance was 4 Ω or more and less than 5 Ω was evaluated as "good", the case where the connection resistance was 5 Ω or more and less than 6 Ω was evaluated as "Δ", and the case where the connection resistance was 6 Ω or more was evaluated as "x".

[ example 1]

A conductive adhesive material was prepared by mixing 20 parts by mass of phenoxy resin (YD-50, manufactured by Nippon iron chemical Co., Ltd.), 30 parts by mass of liquid epoxy resin (EP 828, manufactured by Mitsubishi chemical Co., Ltd.), 20 parts by mass of acid anhydride curing agent (HNA-100, manufactured by Nippon iron chemical Co., Ltd.), 15 parts by mass of acrylic rubber (テイサンレジン SG80H, manufactured by ナガセケムテックス (Co., Ltd.), 15 parts by mass of polybutadiene rubber (RKB series, manufactured by レジナス chemical Co., Ltd.) and 30 parts by mass of Sn-In (52%) solder particles (melting point 117 ℃ C., manufactured by Kikushii Metal industry Co., Ltd.). This was coated on a peeled PET film by using a bar coater, and dried in an oven at 80 ℃ for 5 minutes to prepare a conductive adhesive film having a thickness of 25 μm.

Then, a conductive adhesive film was attached to the front surface electrode portion made of Ag and the rear surface electrode portion made of Al of 6-inch polycrystalline Si unit (size: 15.6 cm. times.15.6 cm, thickness: 180 μm), and a Cu tab wire (width: 2mm, thickness: 0.15 mm) coated with solder on the conductive adhesive film was thermally pressed by a heating head (140 ℃, 15 seconds, 2 MPa) to temporarily fix the conductive adhesive film.

Further, the solar cell to which the tab wire is temporarily fixed is sandwiched by a sheet of sealing adhesive, and is simultaneously laminated with a front cover provided on the light receiving surface side and a back sheet provided on the back surface side. Specifically, while maintaining the heating surface stage of the 2 nd chamber 36 of the pressure reducing laminator 30 shown in fig. 3 at 155 ℃, the 1 st chamber 35 and the 2 nd chamber 36 are depressurized to 133Pa together, and then the 2 nd chamber 36 is kept depressurized to reach the atmospheric pressure at which atmospheric air is introduced into the 1 st chamber 35. After this state was maintained for 5 minutes, the atmosphere was introduced into the 2 nd chamber 36 to reach the atmospheric pressure.

The evaluation results of the adhesiveness and the adhesiveness of the solar cell module were evaluated as "o", and the evaluation results of the connection reliability were evaluated as "o" in the initial stage and as "Δ" after the TH test. Table 1 shows their results.

[ example 2]

A conductive adhesive film was produced in the same manner as in example 1, except that Sn-Bi (58%) solder particles (melting point 139 ℃ C., manufactured by Kikusho Metal industries, Ltd.) were used. A solar cell module was produced in the same manner as in example 1 using this conductive adhesive film.

The evaluation results of the adhesiveness and the adhesiveness of the solar cell module were evaluated as o, and the evaluation results of the connection reliability were excellent in the initial stage and good after the TH test. Table 1 shows their results.

[ example 3]

A conductive adhesive film was produced in the same manner as in example 1, except that Sn-Bi (50%) solder particles (melting point 150 ℃ C., manufactured by Kikusho Metal industries, Ltd.) were used. A solar cell module was produced in the same manner as in example 1 using this conductive adhesive film.

The evaluation results of the bondability of the solar cell module were very excellent, the evaluation results of the adhesiveness were very excellent, and the evaluation results of the connection reliability were very excellent in the initial stage and very excellent after the TH test. Table 1 shows their results.

[ example 4]

A conductive adhesive film was produced in the same manner as in example 1, except that Sn-Pb (37%) solder particles (melting point 183 ℃, manufactured by Kikusho metals industries, Ltd.) were used.

A solar cell module was produced in the same manner as in example 1, except that the temporary fixing was performed at 180 ℃.

The evaluation results of the adhesiveness and the adhesiveness of the solar cell module were evaluated as "o", and the evaluation results of the connection reliability were evaluated as "o" in the initial stage and as "Δ" after the TH test. Table 1 shows their results.

[ example 5]

A conductive adhesive film was produced in the same manner as in example 1, except that a phenol-based curing agent (TD-2131, manufactured by DIC Co., Ltd.) was used instead of the acid anhydride-based curing agent and Sn-Bi (50%) solder particles (melting point 150 ℃ C., manufactured by Kikusan Metal industries Ltd.) were used. A solar cell module was produced in the same manner as in example 1 using this conductive adhesive film.

The evaluation results of the bonding property and the adhesion property of the solar cell module were Δ, and the evaluation results of the connection reliability were ≈ in the initial stage and Δ after the TH test. Table 1 shows their results.

[ example 6]

A conductive adhesive film was produced in the same manner as in example 1, except that Sn-Pb (37%) solder particles (melting point 183 ℃, manufactured by Kikusho metals industries, Ltd.) were used.

A solar cell module was produced in the same manner as in example 4, except that the temporary fixing was performed at 180 ℃ under heat and pressure, and the heating stage of the 2 nd chamber 36 of the pressure reducing laminator 30 shown in fig. 3 was maintained at 200 ℃.

The evaluation results of the adhesiveness and the adhesiveness of the solar cell module were Δ, and the evaluation results of the connection reliability and the TH test were Δ. Table 1 shows their results.

[ Table 1]

Comparative example 1

An electrically conductive adhesive film was produced in the same manner as in example 1, except that an organic acid dihydrazide curing agent (アミキュア UDH-J, manufactured by kayaku ファインテクノ) was used instead of the acid anhydride curing agent, and Sn — Bi (50%) solder particles (having a melting point of 150 ℃, manufactured by sumo metal industries, inc.). A solar cell module was produced in the same manner as in example 1 using this conductive adhesive film.

The evaluation results of the bonding property and the adhesion property of the solar cell module were x, and the evaluation results of the connection reliability and the TH test were x in the initial stage and x. Table 2 shows their results.

Comparative example 2

A conductive adhesive film was produced in the same manner as in example 1, except that an imidazole curing agent (ノバキュア HX 3941HP, manufactured by asahi chemical イーマテリアルズ corporation) was used instead of the acid anhydride curing agent, and Sn — Bi (50%) solder particles (melting point 150 ℃, manufactured by saiko metal industries, inc.). A solar cell module was produced in the same manner as in example 1 using this conductive adhesive film.

The evaluation results of the bonding property and the adhesion property of the solar cell module were x, and the evaluation results of the connection reliability and the TH test were x in the initial stage and x. Table 2 shows their results.

[ Table 2]

In comparative example 1 using an organic acid dihydrazide curing agent and comparative example 2 using an imidazole curing agent, solder wettability was not observed and good connection reliability was not obtained. On the other hand, in examples 1 to 4 and 6 using an acid anhydride curing agent and example 5 using a phenol curing agent, solder wettability was observed. That is, according to examples 1 to 6, since the flux function is exhibited in the conductive adhesive film using the solder particles, good connection reliability can be obtained.

As is clear from examples 1 to 3, by using the connection method in which the curing of the sealing resin and the connection of the electrode and the tab wire are simultaneously performed, good connection reliability can be obtained. Further, as is clear from examples 4 and 6, even when the electrodes were connected to the tab wire at the time of (temporary) fixing by the heating and pressing head, good connection reliability was obtained.

Further, since the difference between the curing start temperature of the curing agent and the melting point of the solder particles was 15 ℃ or less, high evaluation results were obtained in all of the bondability, the adhesiveness, and the connection reliability (examples 2 and 3).

[ notation ] to show

1 solar cell module, 2 solar cell unit, 3 tab wire, 4 wire, 5 substrate, 6 sheet, 7 surface cover, 8 back sheet, 9 metal frame, 10 photoelectric conversion element, 11 bus bar electrode, 12 finger electrode, 13 Al back surface electrode, 20 conductive adhesive film, 30 decompression laminating machine, 31 upper unit, 32 lower unit, 33 sealing member, 34 flexible sheet, 35 st chamber, 36 nd chamber, 2 nd chamber, 37, 38 piping, 39, 40 switching valve, 41 platform

Claims (9)

1. The conductive adhesive material comprises a film-forming resin, a liquid epoxy resin, a curing agent and conductive particles, wherein the curing agent is an acid anhydride curing agent or a phenol curing agent, and the conductive particles are solder particles.

2. The conductive adhesive material according to claim 1, wherein the curing agent is an acid anhydride curing agent, and the acid anhydride curing agent is an alicyclic acid anhydride having a norbornene skeleton.

3. The conductive adhesive material according to claim 1 or 2, wherein a curing start temperature of the curing agent is not less than a melting point of the solder particles.

4. The conductive adhesive material according to claim 3, wherein a difference between a curing start temperature of the curing agent and a melting point of the solder particles is 15 ℃ or less.

5. The conductive adhesive material according to claim 3 or 4, wherein the melting point of the solder particles is 135 ℃ or higher and 150 ℃ or lower.

6. A solar cell module in which a front surface electrode of one solar cell and a rear surface electrode of another solar cell adjacent to the one solar cell are electrically connected to each other by a tab wire through a conductive adhesive material, wherein the conductive adhesive material contains a resin, a liquid epoxy resin, a curing agent and conductive particles, the curing agent is an acid anhydride-based curing agent or a phenol-based curing agent, and the conductive particles are solder particles.

7. A method for manufacturing a solar cell module, wherein a front surface electrode of one solar cell and a rear surface electrode of another solar cell adjacent to the one solar cell are electrically connected to each other by a tab wire through a conductive adhesive material containing a forming resin, a liquid epoxy resin, a curing agent and conductive particles, the curing agent is an acid anhydride-based curing agent or a phenol-based curing agent, the conductive particles are solder particles,

the method comprises the following steps:

a temporary arrangement step of temporarily arranging the front surface electrode and the tab wire of the one solar cell and the rear surface electrode and the tab wire of the other solar cell with the conductive adhesive material therebetween; and

and a pressing step of pressing the joint wire from the upper surface thereof by a heating pressing head.

8. A method for manufacturing a solar cell module, wherein a front surface electrode of one solar cell and a rear surface electrode of another solar cell adjacent to the one solar cell are electrically connected to each other by a tab wire through a conductive adhesive material containing a forming resin, a liquid epoxy resin, a curing agent and conductive particles, the curing agent is an acid anhydride-based curing agent or a phenol-based curing agent, the conductive particles are solder particles,

the method comprises the following steps:

a temporary arrangement step of temporarily arranging the front surface electrode and the tab wire of the one solar cell and the rear surface electrode and the tab wire of the other solar cell with the conductive adhesive material therebetween; and

and a laminating and pressure-bonding step of laminating a sealing material and a protective base material in this order on the upper and lower surfaces of the solar cell, laminating and pressure-bonding the sealing material by a laminating device from the upper surface of the protective base material, and connecting the front surface electrode and the tab wire and the rear surface electrode and the tab wire while curing the sealing material.

9. The method for manufacturing a solar cell module according to claim 8, wherein a temperature of the lamination and compression bonding step is higher than a melting point of the solder particles.