JP2015065388A - Collector sheet for solar cell module and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a collector sheet for solar cell module combining the rust-prevention of a metal wiring part and the solder processing suitability with high level.SOLUTION: In a collector sheet 1 for solar cell module where metal wiring 3 is laminated on the surface of a resin base material 2, a surface shape pattern 33 consisting of a plurality of non-through holes 330 is formed on the surface of the metal wiring 3. The collector sheet 1 can be produced by a production method for forming a plurality of half-etching through holes 41 in a resist film 4 in the resist film formation step, and forming a surface shape pattern consisting of a plurality of non-through holes 330 in the surface of the metal wiring 3, in the etching step.

Description

  The present invention relates to a current collector sheet for a solar cell module used for extracting electricity from a solar cell element, and a method for manufacturing the current collector sheet.

  In recent years, solar cells have been attracting attention as a clean energy source due to increasing awareness of environmental issues. There are various types of methods for extracting electricity from the solar cell element, but in order to increase the light receiving efficiency of sunlight, electrodes are not arranged on the sunlight receiving surface side, but different polarities on the non-light receiving surface side The development of a back contact type solar cell element in which a plurality of electrodes having the above is arranged is in progress.

  There are various types of back contact solar cell elements. Comb-shaped p-type and n-type diffusion layers are formed on the back surface of the MWT and EWT solar cell elements having through holes penetrating the light-receiving surface and the non-light-receiving surface. In addition, there is an IBC solar cell element having a structure for taking out electricity from the n region. In addition, a self-collecting back contact solar cell element having a current collecting wiring portion on the non-light-receiving surface side has been developed.

  A plurality of these back-contact solar cell elements are usually provided inside the solar cell module, and are configured to obtain necessary voltages and currents when they are connected in series and parallel. In order to extract electricity safely and efficiently from a large number of electrodes provided on the non-light-receiving surface side, a solar cell module current collector sheet (hereinafter also simply referred to as “current collector sheet”) as shown in FIG. 6 is proposed. (See Patent Document 1).

  The solar cell module current collector sheet 1 shown in FIG. 6 has a complicated shape such as a comb shape to be a metal wiring portion in order to wire a plurality of back contact solar cell elements 5 inside the solar cell module. The metal wiring part 3 provided is formed on the surface of the resin base material 2 by etching. In such a current collector sheet, the metal wiring portion 3 and the output electrode of the solar cell element 5 are electrically joined by soldering.

  By the way, the surface of the copper foil widely used as the material of the metal wiring part is very easily oxidized. And the surface of the oxidized copper foil is remarkably inferior in wettability to solder. Therefore, the surface of the copper foil used as a metal wiring part needs an antirust process.

  In this respect, in a printed wiring board, a method of applying a rust-preventive coating on the surface of a copper foil that becomes a metal wiring part (see Patent Document 2), and a film that forms a complex structure with copper is formed on the surface of the metal wiring part. As in the method (see Patent Document 3), the surface of the conductive base material that becomes the metal wiring portion is subjected to a rust prevention treatment with an organic rust inhibitor. In such a rust-proof printed wiring board, since the oxidation of the surface of the metal wiring part is suppressed, good wettability with respect to solder is maintained, and the electronic component to the printed wiring board by soldering is maintained. This is preferable from the viewpoint of secure mounting.

  However, current collecting sheets for solar cell modules are used in a state where they are bonded to solar cell elements while being exposed to sunlight over a long period of decades. For this reason, when an anticorrosive treatment using an organic anticorrosive agent is applied like a printed wiring board, the organic anticorrosive agent itself or itself decomposes during the long-term use. The compound produced in this manner may adversely affect the solar cell element and cause the performance deterioration of the solar cell module.

  The conductive base material forming the metal wiring portion of the current collector sheet requires rust prevention treatment that does not use an organic rust inhibitor. As such a rust prevention process, the process which provides a rust prevention layer on copper foil by the plating containing chromium and zinc is performed (refer patent document 4).

JP 2007-081237 A Japanese Patent Laid-Open No. 9-326549 JP-A-6-006018 JP 2000-178787 A

  However, as the conductive base material for forming the metal wiring portion of the current collector sheet, the copper foil described in Patent Document 4, that is, the copper foil on which a rust prevention protective layer is formed with an inorganic rust inhibitor such as chromium is used. In this case, it is possible to prevent deterioration of wettability with respect to solder due to oxidation of the copper foil, while inorganic rust preventives such as chromium forming a rust preventive protective layer prevent the wettability of the metal wiring part against solder. There has been a problem that the reliability of joining of the electrode of the solar cell element and the current collector sheet by soldering is lowered.

  This invention makes it a subject to provide the current collection sheet | seat for solar cell modules which made the rust prevention property of a metal wiring part, and solder processing suitability compatible at a high level.

  As a result of intensive studies to solve the above problems, the present inventors have formed a surface shape pattern composed of a plurality of non-through holes on the surface of the metal wiring part, thereby preventing rust prevention of the metal wiring part. The present inventors have found that soldering suitability can be achieved at a high level and have completed the present invention. More specifically, the present invention provides the following.

  (1) A current collecting sheet for a solar cell module in which a metal wiring portion is laminated on a surface of a resin base material, and a surface shape pattern including a plurality of non-through holes is formed on the surface of the metal wiring portion. A current collecting sheet formed.

  (2) The current collecting sheet according to (1), wherein the plurality of non-through holes are arranged at substantially equal intervals.

  (3) The non-through hole has a substantially spherical inner space, and the opening diameter is smaller than the maximum horizontal diameter of the inner space. (1) or (2) Current collector sheet.

  (4) The current collecting sheet according to any one of (1) to (3), wherein a rust prevention layer made of an inorganic rust inhibitor is formed on the surface of the metal wiring portion.

  (5) A solar cell module in which the surface of the metal wiring portion in the current collector sheet according to any one of (1) to (4) and the electrode of the solar cell element are joined by soldering.

  (6) The solar cell module according to (5), wherein the solar cell element is a back contact type solar cell element.

  (7) A method for producing a current collector sheet according to any one of (1) to (4), wherein a lamination step of obtaining a laminate by laminating a metal foil on the surface of the resin substrate, and the metal foil A resist film forming step of forming a resist film by applying a resist film material by printing on the surface, an etching step of removing a metal wiring portion non-formed portion of the metal foil by an etching process, and removing the resist film A peeling step for exposing and forming a wiring pattern, wherein in the resist film forming step, a plurality of through holes for half etching are formed in the resist film, and in the etching step, a plurality of holes are formed on the surface of the metal wiring portion. A method for producing a current collector sheet, wherein a surface shape pattern composed of non-through holes is formed by a half etching process.

  (8) The printing method is an intaglio printing method, and a half-etching through hole is formed in the resist film at a portion where an intersection of a bank around the intaglio cell contacts during printing (7) The manufacturing method of the current collection sheet | seat of description.

  ADVANTAGE OF THE INVENTION According to this invention, the current collection sheet | seat for solar cell modules which made the rust prevention property of a metal wiring part and soldering workability compatible at a high level can be provided.

It is a schematic diagram with which it uses for description of the fundamental structure of the current collection sheet | seat for solar cell modules of this invention, (a) is a top view, (b) is sectional drawing in the AA of (a). (A)-(d) is a schematic diagram which shows the embodiment of the manufacturing method of the current collection sheet | seat for solar cell modules of this invention. (A)-(b) is a schematic diagram with which it uses for description of the embodiment of resist film formation in the case of forming a resist film by the intaglio type printing method. (A)-(d) is a schematic diagram with which it uses for description of the half etching process by the resist film peculiar to the manufacturing method of the current collection sheet | seat for solar cell modules of this invention. (A) is a front view of (b). It is a cross-sectional schematic diagram which shows the cross-sectional shape of a metal wiring part provided with a surface shape pattern. It is a perspective view which shows typically a mode that the current collection sheet | seat of this invention is joined to the solar cell element. It is a schematic diagram which shows the layer structure of a solar cell module provided with the current collection sheet | seat of this invention.

  Hereinafter, the collector sheet for the solar cell module of the present invention, the manufacturing method thereof, and the embodiments of the solar cell module and details of the embodiments will be described. In addition, this invention is not limited to the following embodiment etc. at all, In the range of the objective of this invention, it can add and change suitably.

  The current collector sheet of the present invention can be used for solar cell modules in general. In particular, in a solar cell module including a back contact type solar cell element, it exhibits excellent current collecting performance when electricity is taken out from the solar cell element. The back contact type solar cell element in this specification refers to all the solar cell elements in which electrodes are arranged on the back surface side opposite to the light receiving surface when in use. The current collecting sheet of the present invention can be preferably used for any back contact type solar cell element.

<Current collector sheet>
FIG. 1 is a schematic view of a current collecting sheet 1 for a solar cell module. (A) is a top view, (b) is sectional drawing in the AA of (a). As shown in FIG. 1, the current collector sheet 1 has a conductive metal wiring portion 3 made of a metal foil such as a copper foil on the surface of a resin base material 2. The resin substrate 2 is a single layer or multilayer resin sheet. As shown in FIG. 6, the back contact type solar cell element 5 is installed on the metal wiring portion 3 in a manner capable of collecting current.

[Resin substrate]
As the resin base material 2, an insulating resin sheet formed into a sheet shape can be used. Here, the sheet form is a concept including a film form, and there is no difference between them in the present invention. The thickness of the resin sheet is not particularly limited, but is preferably about 50 μm or more and 400 μm or less from the viewpoint of weather resistance, impact relaxation performance, insulation, and balance between manufacturing costs. In addition, such a resin sheet is preferable also in the point which can form a resist film continuously by a roll-to-roll system in a resist film formation process.

Moreover, about the insulation of the resin base material 2, what is necessary is just resin which has the volume specific resistivity which can provide the insulation required for a current collection sheet | seat at the time of integration as a solar cell module. Generally, the volume resistivity of the resin base material 2 is preferably 10 ¹⁴ Ω · cm or more, and more preferably 10 ¹⁸ Ω · cm or more.

  Specific examples of the insulating resin that can be used as the resin substrate 2 are given below. Typical resins include polyester resins such as polyethylene terephthalate (PET), polyphenylene ether (PPE), ethylene-vinyl acetate copolymer resin (EVA), polyethylene resins, polypropylene resins, fluorine resins, and the like. . When the resin base material 2 is a multilayer resin sheet, the same type of resin selected from the above may be used to increase production efficiency, or the back surface of the solar cell module when modularized For the purpose of causing the outermost resin sheet on the side to function as a so-called back surface protection sheet of the solar cell module, polyphenylene ether (PPE) or fluorine resin, which is particularly excellent in weather resistance, is used as the resin base material 2. It can also be used.

[Metal wiring section]
The metal wiring part 3 is a metal wiring part made of a conductive base material such as a copper foil laminated on the surface of the current collector sheet 1. The metal wiring part 3 has a function of taking out electricity from the plurality of solar cell elements 5. Therefore, the metal wiring portion is actually formed on the surface of the resin base material 2 as a complicated pattern in which a plurality of fine comb-shaped metal wiring portions are arranged close to each other without intersecting or contacting each other. ing. And the current collection sheet | seat 1 of this invention is that the surface shape pattern 33 which consists of several non-through-holes 310 is formed in the surface of the metal wiring part 3, as shown in FIG.3 (c) and FIG.4. Features. By forming the surface shape pattern 33, a very small part of a metal foil such as a copper foil is limitedly exposed regardless of the surface treatment for protection against rust. It is a feature of the current collector sheet 1 of the present invention that the suitability of the part 3 for soldering, particularly the wettability of solder during soldering can be remarkably improved.

The non-through holes 330 constituting the surface shape pattern 33 are recesses formed in the surface of the metal wiring part without penetrating the metal wiring part 3. The number and range of formation are not particularly limited, but it is preferable that a large number are formed evenly distributed over a predetermined part or substantially the entire surface of the metal wiring portion 3. For example, the non-through holes 330 having an opening diameter of about 0.005 mm to 0.04 mm have a density of about 50 to 1,000 per 1 cm ² of the surface of the metal wiring portion 30 made of copper foil or the like. The aspect formed on a predetermined part or substantially the entire surface of the surface shape pattern 33 can be given as a preferred specific example of the surface shape pattern 33. The depth of the non-through hole 330 is preferably about 0.005 mm to 0.04 mm within approximately 80% of the thickness of the metal wiring portion 3. In addition, the predetermined part of the surface of the metal wiring part 3 in the above can be given as an example of a specific range, for example, only a range where the solar cell element is solder-bonded in a later step.

Further, the shape of the individual blind holes 330, as shown in FIG. 5, has an internal space of substantially spherical, it is smaller in the horizontal direction of the maximum diameter W ₂ opening size W ₁ than the interior shape That is, it is preferable that the vertical cross-sectional shape in the vicinity of the opening on the inner wall surface is an inversely tapered shape that spreads from the opening toward the inside. Thereby, the anchor effect by the non-through-hole 330 is expressed, and the improvement effect of soldering suitability, especially adhesion stability after soldering and adhesion durability becomes remarkable.

  In addition, according to the manufacturing method of the current collection sheet | seat of this invention, in an etching process, half etching process is performed to some metal foil 3A, such as copper foil used as the metal wiring part 3, of said preferable aspect. The non-through holes 330 can be formed at a desired density in a desired range, whereby the desired surface shape pattern 33 can be formed on the surface of the metal wiring portion 3. In addition, as described later, the surface shape pattern 33 can be easily realized by disposing a plurality of non-through holes 330 at substantially equal intervals according to the manufacturing method of the present invention.

  What is necessary is just to set suitably about the thickness of the metal wiring part 3 according to the magnitude | size of the electric current resistance requested | required of the current collection sheet | seat 1 for solar cell modules. Although the thickness of the metal wiring part 3 is not specifically limited, 10 micrometers-50 micrometers are mentioned as an example.

  Examples of the material of the conductive base material for forming the metal wiring portion 3 include metals and metal compounds, and it is essential that these materials can be etched. Examples of the metal or metal compound include metals such as copper, aluminum, nickel, iron, gold, silver, indium, antimony, tin, and zinc, and metal compounds such as oxides, nitrides, sulfides, and carbides of the above metals. Can be mentioned. Furthermore, examples of the material constituting the metal wiring part 3 include composite materials of the metal and the metal compound (for example, indium tin oxide (ITO) and antimony tin oxide (ATO)). Among them, in the production method of the present invention, a rust-proofing treatment is required on the surface, but a copper foil that is excellent in conductivity and workability and is easily available can be particularly preferably used.

  The metal wiring portion 3 needs to have high conductivity, and the surface resistance value is preferably 500Ω / □ or less, more preferably 300Ω / □ or less, further preferably 100Ω / □ or less, and particularly preferably 50Ω / □ or less. The lower limit is about 0.005Ω / □.

  In addition, it is preferable that the surface of the metal wiring part 3 is formed with an anticorrosive protective layer (not shown) made of an inorganic anticorrosive agent for preventing the surface of the copper foil or the like from being oxidized. Such a rust prevention protective layer may be a thin film layer made of, for example, chromium or zinc, but more preferably does not contain chromium. These rust-preventing protective layers adversely affect the soldering suitability required for the metal wiring portion, but the current collecting sheet 1 of the present invention has a surface shape pattern on the surface of the metal wiring portion 3. 33 is formed, for example, it exhibits a sufficiently preferable soldering suitability even when a rust-proofing protective layer with these inorganic rust-proofing agents is formed on the surface of the metal wiring part 3, for example. sell.

When forming a rust prevention protective layer in the current collection sheet 1, the adhesion amount of a rust prevention agent is not specifically limited, What is necessary is just the range which can acquire a required rust prevention effect. As an example, when a general rust preventive agent composed of zinc and chromium is used, the adhesion amount is preferably more than 0.5 mg / m ² and not more than 20 mg / m ² . When the adhesion amount of the inorganic rust preventive agent forming the rust preventive protective layer is within such a range, the current collecting sheet 1 has a rust preventive property and good solderability while keeping the manufacturing cost low. Can be combined at a very favorable level.

  The formation method of said rust prevention protective layer is not specifically limited, It can form by galvanization, zinc sputter | spatter, and vapor deposition. Especially, a conventionally well-known electroplating method can be used preferably. In addition to zinc, the plating solution may contain a complexing agent or ammonia water as required. As plating conditions, it is preferable that the temperature of the plating solution is in the range of 15 ° C to 50 ° C.

<Production method of current collector sheet>
The manufacturing method of the current collection sheet of this invention is equipped with a lamination process, a resist film formation process, an etching process, and a peeling process similarly to the method with the conventional chemical etching process.

  However, in the method for producing a current collector sheet of the present invention, a plurality of fine half-etching through holes 41 are formed in the resist film 4 in the resist film forming step, and the half-etching through holes are formed in the etching step. In the portion where 41 is formed, the surface of the metal wiring part 3 is half-etched to form a plurality of non-through holes 330, and the surface shape pattern 33 constituted by the plurality of non-through holes 330 is formed. It is characterized in that it is formed on the surface of the metal wiring part 3. Hereinafter, the manufacturing method of the current collector sheet of the present invention will be sequentially described with reference mainly to FIGS.

[Lamination process]
In the manufacturing method of the present invention, first, as shown in FIG. 2 (a), a metal foil 3A such as a copper foil used as a material for the metal wiring portion 3 is laminated on the surface of the resin substrate 2, and the material of the current collector sheet. To obtain a laminate. As a lamination method, a method of adhering the metal foil 3A to the surface of the resin base material 2 with an adhesive, or a plating method or a vapor deposition method (sputtering, ion plating, electron) directly on the surface of the resin base material 2 Examples thereof include a method of depositing the metal foil 3A by beam deposition, vacuum deposition, chemical vapor deposition, or the like. From the viewpoint of uniformly and stably laminating a metal foil having a relatively small thickness, a vapor deposition method is preferably used. From the viewpoint of cost, a method of bonding the metal foil 3A to the surface of the resin substrate 2 with an adhesive is advantageous. In the case of bonding, a method of bonding the metal foil 3A to the surface of the resin base material 2 by a dry laminating method using an adhesive such as urethane, polycarbonate, or epoxy is preferable.

[Resist film forming step]
In this step, as shown in FIG. 2B, a resist film 4 patterned in the shape of the metal wiring portion 3 is formed on the surface of the metal foil 3A of the laminate obtained in the lamination step. As shown in FIG. 2C, this resist film 4 is provided in the etching process to be described later so that the metal wiring part forming portion of the metal foil 3A to be the metal wiring part 3 is free from corrosion by the etching solution in the future. . In addition, as shown in FIG.2 (d), the resist film 4 needs to be what can be stripped with an alkaline stripping solution in the stripping step described later.

  Furthermore, it is preferable to form a plurality of fine half-etching through holes 41 in the resist film 4 as shown in FIGS. 3B and 4A in this step. In this case, the half-etching through hole 41 is formed at a position corresponding to the formation position of the non-through hole 330 in the metal wiring portion 3. Due to the presence of the half-etching through holes 41, in a later etching process, a plurality of non-through holes 330 as shown in FIG. It can be formed on the surface of the portion 3. What is necessary is just to adjust the hole diameter of the through-hole 41 for half etching suitably by etching conditions. As a preferred example, a through hole of about 0.005 mm to 0.03 mm penetrating the resist film 4 corresponds to a preferable density of the above-described non-through holes 330 in a range corresponding to a range where the surface shape pattern 33 should be formed. An example of forming them can be given.

  In order to form the half-etching through hole 41 as described above in the resist film 4, the resist film 4 is formed by applying a resist film material (resist liquid) by an intaglio printing method such as gravure printing. Is preferably performed. FIGS. 3A and 3B schematically show an embodiment in which the resist film 4 having the half-etching through holes 41 is formed by an intaglio printing method.

  As shown in FIGS. 3A and 3B, when the resist film 4 is formed by the intaglio printing method, the portion corresponding to the intersection of the bank around each cell of the intaglio, that is, at the time of applying the resist film material. In the portion where these intersections contact the metal foil 3A, a blank portion X of the resist film material to which the resist film material is not applied is inevitably formed. Normally, this blank portion X is eliminated by the ink leveling process, but this blank portion X is intentionally adjusted by adjusting the shape and size of the bank around the intaglio cell or the conditions of the ink leveling process. Can remain. The blank portion X becomes a half-etching through hole 41 in the resist film 4. In this way, the resist film 4 having a plurality of fine half-etching through holes 41 can be formed by applying a resist film material by an intaglio printing method.

  In general, the intersections of the bank portions around each cell of the printing intaglio are regularly arranged at equal intervals. Therefore, it is possible to easily form the half-etching through holes 41 at substantially equal intervals by using a general-purpose printing intaglio as it is without performing special additional processing. That is, according to the manufacturing method of the present invention, the surface shape pattern 33 is provided with the plurality of non-through holes 330 at substantially equal intervals without any particular difficulty in terms of technology and manufacturing cost. It can be.

  As the intaglio printing method, a gravure printing method is particularly preferable. Among the gravure printing methods, there are a direct gravure printing method and an offset gravure printing method, and both of these printing methods are preferably used. In particular, the direct gravure printing method is a roll-to-roll method in which metal is stably and continuously. It is preferable because a resist film having a wiring portion shape can be formed.

  The resist film 4 is preferably a film obtained by curing a thermosetting or active energy ray-curable resist film forming composition, and is particularly a film obtained by curing an active energy ray-curable resist composition. It is preferable. The active energy ray-curable resist composition comprises a monomer and / or oligomer having one or more ethylenically unsaturated groups and one or more ethyleneoxy groups in one molecule, and a carboxyl group in one molecule. It is preferable to include at least one resin having at least one and having an acid value of 50 or more and less than 200. The viscosity of the resist composition (viscosity at 25 ° C.) is preferably in the range of 0.03 to 30 Pa · s, more preferably in the range of 0.1 to 10 Pa · s at a shear rate of 100 (1 / s). In particular, the range of 1 to 10 Pa · s is preferable.

  As for the thickness of the resist film 4, it is preferable to make the thickness of the resist film 4 as small as possible in order to form a metal wiring portion having a smaller line width. From this viewpoint, the thickness of the resist film 4 is preferably small. Further, reducing the thickness of the resist film 4 can reduce raw material costs, shorten the resist film 4 peeling process, and a stripping solution used in the resist film 4 peeling process ( There are advantages such as being able to suppress deterioration of the aqueous alkali solution. Therefore, in the present invention, the resist film 4 preferably has an average thickness of 4 μm or less.

[Etching process]
As shown in FIGS. 2 and 4, in this etching process, the metal wiring part non-formed part 32A, which is a part where the metal wiring part 3 is not formed on the metal foil 3A, is removed by an etching process.

As an etching method, a chemical etching method is used. The chemical etching method is a method in which the metal wiring portion non-formed portion 32A that is an unnecessary metal foil portion other than the metal wiring portion forming portion 31A protected by the resist film 4 is removed by dissolving with an etching solution. Examples of the etching solution used in the chemical etching method include a ferric chloride aqueous solution, a cupric chloride aqueous solution, and an alkaline etching solution. Among them, ferric chloride (FeCl ₃ ) having a Baume specific gravity of 30 to 45 can be preferably used in the production method of the present invention. The temperature of the etching solution used in the etching process by the chemical etching method is suitably in the range of 20 to 60 ° C, and preferably in the range of 25 to 50 ° C. The treatment time is suitably in the range of 10 to 300 seconds, and preferably in the range of 20 to 180 seconds.

  FIGS. 4A to 4D are diagrams schematically illustrating a process in which the non-through holes 330 and the surface shape pattern 33 made of these are formed by half etching. 4A is a schematic plan view, and FIGS. 4B to 4D are schematic cross-sectional views. As shown in FIG. 4A and FIG. 4B which is a schematic cross-sectional view thereof, by forming a plurality of half-etching through holes 41 in the resist film 4 in advance, FIG. As shown, the half-etching process can be performed on the surface of the metal wiring portion 30 in the portion of the half-etching through hole 41. Thereby, as shown in FIG.4 (d), the desired non-through-hole 330 can be formed in the surface of the metal wiring part 3. FIG.

  In addition, when the formation of the resist film 4 is performed by gravure printing, there may be a problem that the resist film material remains on the non-formed part of the metal wiring part 3 in the resin base material 2. This problem can be avoided by spraying the etching solution in such a manner that a spray pressure higher than a predetermined pressure is applied to the resist film 4. More specifically, the spray pressure in this case is preferably such that the etching solution is sprayed at a spray pressure of 0.2 MPa to 0.7 MPa.

[Peeling process]
As shown in FIGS. 2C to 2D and FIGS. 4C to 4D, in this step, the resist film 4 is removed using an alkaline stripping solution. Through this step, the resist film 4 is removed from the surface of the metal wiring portion 3. Examples of the alkaline stripping solution used in the stripping step include an aqueous solution of caustic soda having a predetermined concentration. The temperature of these alkaline stripping solutions is preferably in the range of 20 to 60 ° C, more preferably in the range of 30 to 55 ° C. The treatment time with the alkaline stripping solution is preferably in the range of 5 to 100 seconds, and more preferably in the range of 20 to 80 seconds.

<Solar cell module>
Next, the solar cell module 100 in which the current collector sheet 1 of the present invention is used will be described. FIG. 7 is a schematic cross-sectional view showing an example of the layer configuration of the solar cell module 100. The solar cell module 100 includes, from the light receiving surface side, a transparent front substrate 101 made of glass or the like, a front sealing material layer 7 made of ethylene-vinyl acetate copolymer resin (EVA), ionomer, polyvinyl butyral (PVB), polyethylene, or the like. The solar cell element 5, the current collector sheet 1, the back surface sealing material layer 8, and the back surface protection sheet 9 made of fluorine resin film ETFE, hydrolysis resistant PET, and the like are laminated in this order. Electricity extracted from the solar cell element 5 is extracted from the solar cell module 100 via the metal wiring part 3 of the current collector sheet 1.

  The current collecting sheet 1 is incorporated into a solar cell module and used as electric wiring in the module. A surface shape pattern 33 is formed in the metal wiring portion 3 of the current collector sheet 1 in at least a range connected to the electrode of the solar cell element 5. The metal wiring portion 3 and the electrode of the solar cell element 5 are joined by soldering via the surface shape pattern 33, whereby the current collector sheet 1 and the solar cell element 5 are electrically joined, and the electrical wiring Become.

  Here, the electrode of the solar cell element is an electrode for outputting electric power generated by receiving light from the solar cell element to the outside of the solar cell element. Although not particularly limited, this electrode is made of silver or a silver compound as an example.

  In addition, a conventionally known solder can be used without particular limitation as the solder used in the soldering process. Examples of such solder include lead-tin alloy solder, silver-containing solder, lead-free solder, tin-bismuth, tin-bismuth-silver, and the like. When joining the electrode of a solar cell element and the surface of the metal wiring part 3 which consists of copper foil etc. by soldering via the antirust protection layer 32, a conventionally well-known method can be especially used without a restriction | limiting.

  In the conventional current collector sheet, in order to prevent oxidation of the copper foil or the like constituting the metal wiring part 3, a rust prevention protective layer formed on the surface of the metal wiring part 3 is an essential constituent element. The rust protective layer is a factor that reduces the soldering suitability of the metal wiring portion, and has been an obstacle to improving the stability and reliability of the electrical wiring in the solar cell module 100. However, by using the current collector sheet 1 having the surface shape pattern 33, deterioration of soldering suitability is prevented regardless of the surface treatment mode of the metal wiring portion 3, and the electrical wiring of the solar cell module 100 is prevented. Stability and reliability can be greatly improved.

<Method for manufacturing solar cell module>
A solar cell module 100 including the current collector sheet 1 and the solar cell element 5 of the present invention is formed by laminating and integrating a joined body obtained by joining the current collector sheet 1 and the solar cell element 5 by soldering. Can be manufactured. An example of this integration method is a method of integration by vacuum heat lamination. The laminating temperature when using the above method is preferably in the range of 130 ° C to 190 ° C. The laminating time is preferably in the range of 5 to 60 minutes, particularly preferably in the range of 8 to 40 minutes.

  In this integration process, the resin base material 2 of the current collector sheet 1 is firmly integrated with other members as a solar cell module, so it is heated at Tg or more of the base resin of the current collector sheet 1. However, there is no problem of shrinkage or deformation due to heat.

  According to the manufacturing method of the current collector sheet for the solar cell module and the current collector sheet for solar cell of the present invention described above, the following effects can be obtained.

  (1) The conductive base material made of copper foil used for the metal wiring portion of the current collector sheet must have a surface treatment for the purpose of rust prevention. This has an unfavorable influence on the suitability for soldering required for the metal wiring part. Therefore, in the current collector sheet according to the present invention, this problem has been solved by making an original device on the surface shape of the metal wiring portion. That is, the current collector sheet is characterized in that a surface shape pattern including a plurality of non-through holes is formed on the surface of the metal wiring portion. As a result, regardless of the surface treatment of the metal wiring part for rust prevention, a very small part of the metal foil is limitedly exposed, thereby improving the wettability of the solder and good solder processing. It is possible to provide a current collecting sheet including a metal wiring portion having suitability.

  (2) Further, the surface shape pattern is configured such that a plurality of non-through holes are arranged at substantially equal intervals. Thereby, the dispersion | variation in the adhesiveness by equalization of the adhesive improvement effect can be prevented, and the stability and durability of the solder joint portion after the soldering process of the current collector sheet can be made excellent.

  (3) Further, the non-through hole has a substantially spherical internal space, and the opening diameter is smaller than the horizontal maximum diameter of the internal space. As a result, the anchor effect of the surface shape pattern is enhanced, and the stability and durability of the solder joint portion after soldering of the current collector sheet can be further improved.

  (4) Moreover, it was set as the structure by which the rust prevention layer which consists of an inorganic type rust preventive agent was formed in the surface of a metal wiring part. Thereby, solder processing aptitude can be improved, maintaining the rust prevention property of a metal wiring part.

  (5) A solar cell module is configured using the current collector sheet of the present invention, and the surface of the metal wiring portion and the electrode of the solar cell element are joined by soldering, and did. Thereby, the solar cell module excellent in the reliability and durability of the part concerning electric wiring can be provided.

  (6) The solar cell element is configured as a back contact type solar cell element. By setting it as such a structure, the effect of invention of (5) can be exhibited in a particularly preferable aspect.

  (7) A method for producing a current collector sheet includes a lamination step, a resist film forming step, an etching step, and a peeling step. In the resist film forming step, a plurality of half-etching through holes are formed in the resist film. In the etching step, a surface shape pattern including a plurality of non-through holes is formed on the surface of the metal wiring portion. Thereby, the current collection sheet | seat provided with favorable soldering workability can be manufactured irrespective of the aspect of the surface treatment for rust prevention.

  (8) The resist film printing method was an intaglio printing method. As a result, a half-etching through-hole can be formed on the resist film by a simple method that does not involve substantial additional processing compared to the conventional method at the portion where the intersection of the bank around the intaglio cell contacts during printing. it can. Therefore, the manufacturing method of the current collection sheet of (5) can be implemented under high productivity.

  As described above, the current collector sheet, the method for manufacturing the current collector sheet, and the solar cell module of the present invention have been specifically described with reference to the embodiment and the embodiment, but the present invention is limited to the embodiment and the embodiment. However, the present invention can be implemented with appropriate modifications within the scope of the configuration of the present invention.

DESCRIPTION OF SYMBOLS 1 Current collection sheet 2 Resin base material 3 Metal wiring part 30 Conductive base material 3A Metal foil 31A Metal wiring part formation part 32A Metal wiring part non-formation part 33 Surface shape pattern 330 Non-through-hole 4 Resist film 41 Half-etching through-hole DESCRIPTION OF SYMBOLS 5 Solar cell element 6 Transparent front substrate 7 Front side sealing material layer 8 Back side sealing material layer 9 Back surface protection sheet 100 Solar cell module

Claims (8)

A current collecting sheet for a solar cell module in which a metal wiring portion is laminated on the surface of a resin base material,
A current collecting sheet, wherein a surface shape pattern including a plurality of non-through holes is formed on a surface of the metal wiring portion.   The current collecting sheet according to claim 1, wherein the surface shape pattern has the plurality of non-through holes arranged at substantially equal intervals.   The current collecting sheet according to claim 1, wherein the non-through hole has a substantially spherical inner space, and an opening diameter is smaller than a maximum diameter in a horizontal direction of the inner space.   The current collection sheet according to any one of claims 1 to 3, wherein a rust prevention layer made of an inorganic rust prevention agent is formed on a surface of the metal wiring portion.   The solar cell module in which the surface of the said metal wiring part in the current collection sheet | seat in any one of Claim 1 to 4 and the electrode of a solar cell element are joined by soldering.   The solar cell module according to claim 5, wherein the solar cell element is a back contact type solar cell element. It is a manufacturing method of the current collection sheet according to any one of claims 1 to 4,
A laminating step of laminating a metal foil on the surface of the resin substrate to obtain a laminate;
A resist film forming step of forming a resist film on the surface of the metal foil by applying a resist film material by printing; and an etching step of removing a metal wiring portion non-formed portion in the metal foil by an etching process;
A peeling step of removing the resist film and exposing the wiring pattern,
In the resist film forming step, a plurality of half-etching through holes are formed in the resist film, and in the etching step, a surface shape pattern consisting of a plurality of non-through holes is half-etched on the surface of the metal wiring portion. The manufacturing method of the current collection sheet formed by this.   The collection method according to claim 7, wherein the printing method is an intaglio printing method, and a half-etching through hole is formed in the resist film at a portion where an intersection of a bank portion around the intaglio cell contacts during printing. Electric sheet manufacturing method.

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