JP2014013838A - Solar battery power collecting sheet and solar battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent invasion of moisture to an insulating layer constituting a power collecting sheet.SOLUTION: A solar battery power collecting sheet includes: wiring 12 that is arranged on a light non-reception surface side of a back contact type solar battery element as internal wiring in a solar battery module, formed on the front surface of a resin substrate 11, and constituted by a conductive body; an insulating layer 13 formed to cover the wiring 12; and a sealing material layer 14 formed on the insulating layer 13. Continuity recessions 16 where the wiring 12 is exposed in order to attain continuity between electrodes on the light non-reception surface side of the solar battery element and the wiring 12 corresponding to the electrodes are formed via the insulating layer 13 and the sealing material layer 14 in the insulating layer 13 and the sealing material layer 14 on the wiring 12. End surfaces of the insulating layer 13 are covered with the sealing material layer 14. It is indispensable that the sealing material layer 14 has a shape to cover the insulating layer 13. Besides, a module end surface sealing shape with the use of a sealing material is simultaneously covered, by which even the invasion of moisture from the side surface of the resin substrate 11 adhering to the insulating layer 13 is prevented.

Description

  The present invention relates to a solar cell current collector sheet for extracting electricity from a back contact solar cell element, and a solar cell module using the same.

  In recent years, with increasing awareness of the environment, the supply of energy by solar cell power generation has attracted attention and has been put into practical use.

  Solar cell elements that form the heart of solar cells that directly convert solar energy into electricity are those that use monocrystalline or polycrystalline silicon cells (crystalline silicon cells), amorphous silicon, or compound semiconductors. A thing (thin film cell) or the like is used. It has a function of generating electric power when sunlight enters the solar cell element. Generally, a solar cell element is used by forming a solar cell module in order to connect a plurality of solar cell elements in order to generate a practical electric output and protect the solar cell element.

  The solar cell module covers the light-receiving surface with a transparent front substrate such as glass, sequentially laminates a surface sealing material layer, a solar cell element, a back surface sealing material layer, a back surface protection sheet, etc. The sealing material layer is melted and bonded through a process of heating at a temperature equal to or higher than the melting temperature of the resin constituting the sealing material layer (a temperature condition of 150 ° C. in the case of EVA) and a pressing process.

  As described in Patent Document 1, a plurality of solar cell elements that generate power inside a solar cell module are usually provided inside the solar cell module, and are necessary by connecting them in series or in parallel. It is configured to obtain a stable voltage and current. In order to wire a plurality of solar cell elements inside the solar cell module, for example, a solar cell current collector sheet in which a metal foil to be a wiring is laminated on the surface of a resin sheet as a base material is used.

  The solar cell element includes a light receiving surface that receives sunlight and a non-light receiving surface positioned on the back side thereof, but in order to increase the light receiving efficiency of sunlight on the light receiving surface, no electrode is disposed on the light receiving surface, A back contact type solar cell element in which a plurality of electrodes having different polarities are arranged on a non-light receiving surface is known.

  There are various types of back contact solar cell elements. Metal Wrap Through (MWT) method or emitter wrap, which includes a semiconductor substrate having a plurality of through holes penetrating the light receiving surface and the non-light receiving surface, and a plurality of electrodes having different polarities provided on the non-light receiving surface In addition to the solar cell element of the through (EWT) type, there is also a solar cell element having a structure having no through hole.

  Here, in particular, when electricity is directly taken out from the electrode of the solar cell element having a through-hole structure, between the non-light-receiving surface side element as the P electrode (positive electrode) and the wiring corresponding to the N electrode (negative electrode) There is a risk of short circuit.

  Such a short circuit can be prevented by forming an insulating layer on the wiring of the solar cell current collector sheet. Patent Document 2 discloses a solar cell module in which an insulating layer made of an insulating adhesive is formed on a circuit of a solar cell current collector sheet.

  In Patent Document 3, the above short circuit can be prevented by further forming a sealing material (filler) layer on the insulating layer formed on the circuit of the solar cell current collector sheet, and A solar cell current collector sheet capable of sufficiently mitigating external impact is described.

JP 2007-081237 A JP 2010-157553 A Japanese Patent Application Laid-Open No. 2012-074585

Since a solar cell module is used outdoors for a long period of time, sufficient durability is required, and in particular, water resistance and water vapor barrier properties are required in addition to weather resistance.
However, when considering the use as outdoor use for a long period of 10 to several decades as a solar cell panel, sufficient weather resistance, water resistance, and water vapor barrier properties are still being obtained. There is a problem that it is difficult to say.

  That is, when used over a long period of time for 10 years or more, there are problems such as corrosion of wiring, generation of leakage current due to deterioration of insulating properties of the insulating layer, peeling of the adhesive interface, deterioration of the solar cell element, and the like.

  Compared to the light-receiving surface of the module sufficiently protected by the transparent front plate and the back surface (non-light-receiving surface) of the solar cell module sufficiently protected by the back surface protection sheet, It has been found that moisture and water vapor enter the module through the insulating layer exposed at the end of the battery module, particularly the end of the solar cell current collector sheet, or the resin base material.

  The interface between the insulating layer and the sealing material layer exposed on the end face of the solar cell module and the interface between the insulating layer and the resin base material are interfaces of different materials. Therefore, as a result of being continuously exposed to moisture and a temperature difference for a long period of 10 years or more outdoors, strain may accumulate at these interfaces and partial peeling may occur. Even if such exfoliation is very small in the initial stage, it is abrupt due to changes in volume accompanying vaporization-liquefaction, liquefaction-solidification (freezing) of moisture in the exfoliation part, accumulation of impurities caused by moisture, etc. Expanding.

  In addition, an adhesive mainly composed of a urethane-based resin adhesive or a polyester-based resin adhesive used for bonding a resin base material and wiring of a solar cell current collector sheet, a resin base material and a back surface protection sheet, Since the resin itself is susceptible to hydrolysis due to moisture absorption and the heat resistance of the resin itself is low, it deteriorates under the influence of heat, humidity, and even ultraviolet rays when used for a long period of time. As a result, the mechanical strength is lowered, and peeling at the adhesion surface is likely to occur.

  Edges where mechanical strength is reduced and peeling occurs on the adhesive surface are more susceptible to moisture, which should eventually be protected from corrosion of solar cell elements and wiring, and deterioration of insulation between wiring. Leakage current is generated due to the above.

  In particular, the interface between the resin base material and the insulating layer of the current collector sheet, and the interface between the insulating layer and the sealing material layer are connected to the wiring, electrodes, and conductive part recesses that are conductive parts, and moisture intrusion and peeling at these interfaces Will seriously damage the life of the solar cell module.

  In view of the above situation, earnest research and development is proceeding, and claim 1 of the present invention is disposed on the non-light-receiving surface side of the back contact type solar cell element 30 for internal wiring in the solar cell module 40, and the resin base material 11. And a wiring 12 made of a conductor, an insulating layer 13 formed so as to cover the wiring 12, and a sealing material layer 14 formed on the insulating layer 13. The insulating layer 13 and the sealing material layer 14 on the wiring 12 are connected to the non-light-receiving surface side electrodes 32 and 33 of the solar cell element 30 via the insulating layer 13 and the sealing material layer 14. Conductive recesses 16 exposing the wirings 12 are formed to conduct the corresponding wirings 12, and end surfaces of the insulating layers 13 are covered with the sealing material layer 14. This is a solar cell current collector sheet 10.

  In addition, Claim 2 of the present invention is disposed on the non-light-receiving surface side of the back contact type solar cell element 30 for internal wiring in the solar cell module 40, formed on a part of the surface of the resin base material 11, and conductive. A wiring 12 made of a body, an insulating layer 13 formed so as to cover the wiring 12, and a sealing material layer 14 formed on the insulating layer 13, and the insulating layer 13 on the wiring 12 and The sealing material layer 14 is electrically connected to the non-light-receiving surface side electrodes 32 and 33 of the solar cell element 30 and the corresponding wiring 12 through the insulating layer 13 and the sealing material layer 14. The solar cell according to claim 1, wherein a conductive recess 16 exposing the wiring 12 is formed, and an end surface of the resin base material 11 is covered with the sealing material layer 14. This is a current collecting sheet 10.

  In addition, Claim 3 of the present invention is the solar cell current collector sheet 10 according to Claim 1 or 2, wherein the sealing material layer 14 is a polyethylene-based resin.

  In addition, according to claim 4 of the present invention, a back surface protection sheet is integrated on the back surface side of the resin base material 11, and the insulating layer 13 is not exposed. It is the collector sheet 10 for back surface protection sheets integrated solar cells as described in any one.

  In addition, claim 5 of the present invention is a solar cell module 40 using the solar cell current collector sheet 10 according to any one of claims 1 to 4.

  According to the present invention described in claim 1, when the solar cell module 40 is formed, the interface between the insulating layer 13, the insulating layer 13 and the resin base material 11, the insulating layer 13 and the sealing material layer 14, etc. The solar cell current collector sheet 10 that is not exposed to the end face of the solar cell module 40 by being covered with the sealing material layer 14 can be realized. Therefore, even when the solar cell module 40 is used for a long period of time, the insulating layer 13 and the interface between the insulating layer 13 and the resin base material 11, the interface between the insulating layer 13 and the sealing material layer 14, and the insulating layer 13 are used. It is not exposed to moisture or water vapor. For this reason, the peeling and deterioration of the interface between the insulating layer 13 and the resin base material 11 and the interface between the insulating layer 13 and the sealing material layer 14 and the like do not rapidly expand, and the solar cell module 40 is prevented from being deteriorated and extended in life. Can be realized.

  Furthermore, when it is set as the solar cell module 40 by providing the structural requirement of Claim 2, when it is set as the resin base material 11, the sealing material layer 14, and the resin base material 11, the resin base material 11 and a back surface protection sheet The solar cell current collector sheet 10 that is not exposed to the end face of the solar cell module 40 can be realized by covering the interface with the sealing material layer 14. Therefore, even when the solar cell module 40 is used for a long period of time, the interface between the resin base material 11 and the sealing material layer 14 and the resin base material 11, the interface between the resin base material 11 layer and the back surface protective sheet, and insulation. The layer 13 itself or the resin substrate 11 itself is not exposed to moisture or water vapor. For this reason, the peeling and deterioration of the interface between the sealing material layer 14 and the resin base material 11 and the interface between the resin base material 11 and the back surface protection sheet do not rapidly expand, and further deterioration prevention and long life of the solar cell module 40 are achieved. Can be realized.

Furthermore, by providing the constituent features of claim 3, the insulating layer 13, the insulating layer 13, and the resin base material 11 are formed by the sealing material layer 14 made of a polyethylene resin having a low water vapor transmission rate and a very low water absorption rate. , The interface between the insulating layer 13 and the sealing material layer 14, the interface between the resin base material 11 and the sealing material layer 14 and the resin base material 11, and the interface between the resin base material 11 and the back surface protective sheet are covered. . For this reason, the water | moisture content and water vapor | steam which accelerates | stimulates peeling and deterioration of these layers and an interface are blocked | blocked more firmly.
Therefore, the solar cell module 40 using the present solar cell light-condensing sheet is protected from deterioration due to moisture or water vapor over a long period of time, and has excellent weather resistance and long life.

  Furthermore, by providing the structural requirements according to claim 4, the insulating layer 13 and the sealing material layer 14 can also be stored as a condensing sheet for a back surface protection sheet integrated solar cell that is an intermediate member. Interface between insulating layer 13 and resin base material 11, interface between insulating layer 13 and sealing material layer 14 and the like, interface between resin base material 11 and sealing material layer 14 and resin base material 11, protection of resin base material 11 and back surface Since the interface with the sheet is covered, moisture and water vapor that promote deterioration and peeling of these layers and the interface are blocked. Therefore, the deterioration factor of the solar cell module 40 is not inherently preserved in the state of the condensing sheet for the back surface protection sheet integrated solar cell that is the intermediate member.

  Furthermore, by providing the structural requirements according to claim 5, it is possible to block moisture and water vapor from entering the solar cell module 40 for a long period of time, and to realize the solar cell module 40 having excellent weather resistance and a long life. it can.

It is a typical perspective view of the current collection sheet for solar cells of the 1st form which is one form of the present invention. It is sectional drawing which follows the XX line of FIG. It is a typical perspective view of the current collection sheet for solar cells of the 2nd form which is one form of the present invention. It is sectional drawing which follows the YY line of FIG. It is typical sectional drawing of the solar cell module using the collector sheet for solar cells of the 1st form which is one form of this invention. It is typical sectional drawing of the solar cell module using the current collector sheet for solar cells of the 2nd form which is one form of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment at all, In the range of the objective of this invention, it can add and change suitably.

  First, FIG. 1 to FIG. 4 show a solar cell current collector sheet 10 of the present embodiment. The solar cell current collector sheet 10 is used to connect a so-called back contact type solar cell element 30 to form a solar cell module 40.

<Solar cell element>
The solar cell element 30 used in the present embodiment is a solar cell condensing sheet used for a so-called back contact type solar cell element 30 having a positive electrode and a negative electrode on the non-light-receiving surface side. Such a solar cell element 30 has little reduction in the area which catches sunlight by obstruction by the electrode of a light-receiving surface. Therefore, it can be said that the solar cell element 30 is excellent in power generation efficiency. As an example, a plurality of through-holes 31 including an N-pole light-receiving surface side element and a P-pole non-light-receiving surface side element stacked on top and bottom, penetrating the light-receiving surface side element and the non-light-receiving surface side element, A first electrode 32 that is a negative electrode formed on the non-light-receiving surface side through the through-hole 31 from the surface-side element, and a second electrode 33 that is a positive electrode formed on the non-light-receiving surface side element are provided. .

  Specific examples of the back contact solar cell element 30 having the through hole 31 include a metal wrap through (MWT) type and an emitter wrap through (EWT) type solar cell element 30. . The solar cell element of the MWT system is a solar cell element 30 in which a metal such as silver paste is filled in the through hole 31, and the power collected on the light receiving surface through the metal is the first electrode 32 (negative electrode) on the non-light receiving surface side. The solar cell element 30 having a structure that is taken out from the electrode). The EWT solar cell element is a diffusion layer provided on the inner wall of the through hole 31 of the solar cell element 30, and the power collected on the light receiving surface through the diffusion layer is from the first electrode 32 (negative electrode) on the non-light receiving surface side. The solar cell element 30 having a structure to be taken out is referred to.

  In this specification, the solar cell element 30 in which the light receiving surface side element is the N pole and the non-light receiving surface side element is the P pole, that is, the first electrode 32 is the negative electrode and the second electrode 33. Illustrates a solar cell element 30 in which is a positive electrode. However, the configuration of the solar cell element 30 is not limited to this. For example, unlike the case of FIG. 1, in the case of the solar cell element 30 having the P-electrode on the light receiving surface side, the positive and negative polarities of the first electrode 32 and the second electrode 33 are reversed. The solar cell current collector sheet 10 of the present invention can also be used for the solar cell element 30 having such a configuration. In this case, the same effect as that of the present embodiment can be obtained.

  Moreover, the solar cell element 30 that can use the solar cell current collector sheet 10 of the present invention is not necessarily limited to the solar cell element 30 having the through hole 31 as described above. The solar cell current collector sheet 10 of the present invention has a configuration that does not have the through hole 31 as long as it is a back contact type solar cell element 30 in which a plurality of electrodes 32 and 33 having different polarities are arranged on the non-light-receiving surface. Even if it is a case where it uses for the solar cell element 30, it can use preferably as the current collection sheet | seat 10 for solar cells which can prevent the penetration | invasion of the above-mentioned water | moisture content or water vapor | steam over a long period of time. As an example, the solar cell current collector sheet 10 of the present invention can also be preferably used for the “interdigitated back-contact (IBC) system” solar cell element 30. Here, the IBC type solar cell element 30 is a solar cell having a structure in which comb-shaped p-type and n-type diffusion layers are formed on the back surface of the solar cell element 30 and electricity is extracted from the p and n regions. It refers to the battery element 30.

<Current collector sheet for solar cell>
The solar cell current collector sheet 10 of this embodiment includes a resin base material 11, a wiring 12, an insulating layer 13, a back surface sealing material layer 14, and a conductive recess 16 formed in a part of the back surface sealing material layer 14. Is provided. A wiring 12 made of a conductor such as copper is formed on a part of the surface of the resin base 11. Then, the wiring 12 connected to the first electrode 32 (negative electrode) of the solar cell module 40 and the wiring connected to the second electrode 33 (positive electrode) of the solar cell module 40 so as to cover the wiring 12. In order to prevent a short circuit with the insulating layer 12, an insulating layer 13 having a sufficient insulation resistance is provided. Further, a back surface sealing material layer 14 is formed on the insulating layer 13. Further, a conductive recess 16 is formed penetrating from the upper surface of the back surface sealing material layer 14 through the insulating layer 13 to the upper book surface of the wiring 12. Furthermore, the end surface of the insulating layer 13 is covered with the sealing material layer 14.

  The resin base material 11 is a resin molded into a sheet shape. Here, the sheet form is a concept including a film form, and there is no difference between them in the present invention. Examples of the resin constituting the resin base material 11 include polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polyvinyl chloride resin, Fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide resin such as various nylons (registered trademark), polyimide resin , Polyamideimide resin, polyarylphthalate resin, silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulose, etc. It is exemplified.

  What is necessary is just to set the thickness of the resin base material 11 suitably according to the intensity | strength, thinness, etc. which are requested | required of the collector sheet 10 for solar cells. Although the thickness of the resin base material 11 is not specifically limited, 20 micrometers or more and 250 micrometers or less are mentioned as an example.

  The wiring 12 is an electrical wiring formed on the surface of the solar cell current collector sheet 10 so as to have a desired wiring shape.

  As a material constituting the wiring 12, a material having a low electrical resistance, for example, copper, aluminum, iron-nickel alloy or the like is used, but it is formed from a material having a lower linear expansion coefficient than the resin constituting the resin base material 11. It is preferable that Moreover, a conductive polymer can also be used. In general, copper is used from the viewpoint of conductivity and good adhesion to other conductive substances (solder or the like).

  For example, in the wiring 12 made of a copper conductor, in order to form the wiring 12 on the surface of the resin base material 11, a copper foil is bonded to the surface of the resin base material 11, and then the copper foil is patterned by an etching process or the like. The method of doing is illustrated.

  What is necessary is just to set the thickness of the wiring 12 suitably according to the magnitude | size etc. of the allowable electric current requested | required of the collector sheet 10 for solar cells. Although the thickness of the wiring 12 is not specifically limited, As an example, 10 micrometers or more and 50 micrometers or less are mentioned.

  As shown in FIGS. 5 and 6, the conductive recess 16 is formed immediately below the first electrode (negative electrode) 32 of the solar cell element 30 when the solar cell element 30 and the solar cell current collector sheet 10 are joined. The first conductive recess 16 and the second conductive recess 16 formed immediately below the second electrode (positive electrode) 33 of the solar cell element 30. The first conductive recess 16 has substantially the same shape and area in plan view as viewed from the upper surface side of the solar cell element 30, and the upper surface of the wiring 12 through the insulating layer 13 from the upper surface portion of the back surface sealing material layer 14. It is a hole penetrating up to. On the other hand, the second conductive recess 16 is also a hole that penetrates from the upper surface portion of the back surface sealing material layer 14 to the upper surface of the wiring 12 through the insulating layer 13, and the shape and area thereof may be bonded to the positive electrode. It is designed appropriately according to the shape position of the positive electrode.

  At the time of joining the solar cell element 30 and the solar cell current collector sheet 10, the first conductive recess 16 is formed at a position overlapping the corresponding through-hole 31 with the first electrode (negative electrode) 32 interposed therebetween, The second conductive recess 16 is formed at a position where it vertically overlaps the corresponding through hole 31 with the second electrode (positive electrode) 33 interposed therebetween. The space between the first conductive recess 16 and the second conductive recess 16 is filled with a conductive material 17.

  As the material of the conductive material 17, a material having a low electric resistance is used. Especially, since the electrical resistance with the wiring 12 becomes low, it is preferable to contain one or more metals selected from the group consisting of silver, copper, tin, lead, nickel, and gold.

  Since the conductive material 17 has a high viscosity and can be easily formed into a desired shape, one or more metals selected from the group consisting of silver, copper, tin, and solder (copper and lead are the main components) are used. It is preferable that the conductive paste is contained.

  The conductive paste is preferably a low temperature curing type. If the conductive paste is a low temperature curing type, the electrodes 32 and 33 of the solar cell element 30 and the wiring 12 can be electrically connected at a low temperature of 120 ° C. or higher and 160 ° C. or lower. 120 ° C. or more and 160 ° C. or less is a temperature at which softening and melting of a material that can be used as the sealing material layer 14 occurs, and therefore, when a polyethylene resin is used as the sealing material layer 14, it can be easily processed. The electrodes 32 and 33 of the solar cell element 30 and the conductive material 17 made of a conductive paste can be more easily electrically connected.

  Low-temperature curing type conductive paste contains a polymer and a conductive filler, and develops conductivity by physical contact of the conductive filler by curing the polymer. Coordinates and reduces silver or copper to organic matter The thing which contains a nanoparticle and expresses electroconductivity by low-temperature sintering (120 to 160 degreeC) is mentioned. The latter material is preferable in that the electric resistance becomes lower. In general, a conductive material 17 in which silver particles and epoxy are mixed is filled.

  As shown in FIGS. 2 and 4, the insulating layer 13 is formed so as to cover the wiring 12 except for the place occupied by the conductive recess 16, the end face 18 of the solar cell current collector sheet, and the end face 41 of the solar cell module. Is done. The insulating layer may be formed in advance except for the place occupied by the conductive recess 16, the end face 18 of the solar cell current collector sheet, and the end face 41 of the solar cell module, or the insulating layer 13 or the back surface thereon. After forming the sealing material layer 14, the conductive recess 16, the end surface 18 of the solar cell current collector sheet, the insulating layer 13 where the end surface 41 of the solar cell module occupies, or the back surface sealing thereon by laser irradiation or the like. The material layer 14 may be removed.

In order to prevent a short circuit between the wiring 12 connected to the first electrode 32 (negative electrode) of the solar cell module 40 and the wiring 12 connected to the second electrode 33 (positive electrode) of the solar cell module 40, The resistance value when the insulating layer 13 and the back surface sealing material layer 14 are integrated and the resistance value is measured as a composite layer is JIS C6481 using a super insulation meter (manufactured by Hioki Electric Co., Ltd .: model number SM-8215). Is required to be 10 ⁷ Ω or more, preferably 10 ¹¹ Ω or more.

  Therefore, in the present invention, as an insulating agent for forming the insulating layer 13, a thermosetting insulating ink such as an epoxy-phenol-based ink having a very high insulating property, which has been widely used conventionally, or an ultraviolet curable insulating agent. An ultraviolet curable insulating coat using can be suitably used. The ultraviolet curable insulating coating agent is inferior to the thermosetting insulating ink in the insulating property when the insulating layer 13 is formed alone. However, even with the insulating layer 13 using an ultraviolet curable insulating coating agent, sufficient insulation can be obtained by forming a composite layer by laminating the back surface sealing material layer 14 thereon. It becomes possible.

  In addition, it can replace with thermosetting insulating ink and can suppress the curing temperature of the ink at the time of formation of the insulating layer 13 mentioned later to low temperature by using an ultraviolet curable insulation coating agent. Thereby, the polyethylene terephthalate (PET) etc. which were excellent in economical efficiency whose glass transition temperature is 100 degrees C or less can be used as the resin base material 11. FIG. Also, UV curing, which requires a short time as a process, is more economical than thermal curing. Therefore, the productivity of the solar cell current collector sheet 10 or the solar cell module 40 can be increased by using an ultraviolet curable insulating coating agent as an insulating agent for forming the insulating layer 13.

  The thickness of the insulating layer 13 is preferably 5 μm or more and 25 μm or less. If it is less than 5 μm, even if the sealing material layer 14 is laminated, insulation is insufficient, which is not preferable. If it exceeds 25 μm, no further effect is obtained, and it is rather difficult to form a pattern of the conductive recess 16. Further, it is not preferable because it is uneconomical.

  As shown in FIGS. 2 and 4, the back surface sealing material layer 14 is formed on the insulating layer 13 except for a place occupied by the conductive recess 16. In addition, the sealing material layer 14 in this invention is also called a filler, for example, an olefin arrange | positioned in the solar cell module 40, in order to fix the position of the solar cell element 30 and to relieve the impact from the outside. The layer which consists of fillers, such as the resin base material 11 of a system, is said. That is, in the present invention, the conductive recess 16 is formed by communication between a recess formed by an unformed portion of the insulating layer 13 and a hole formed in the back surface sealing material layer 14 thereon.

  As a sealing material for forming the back surface sealing material layer 14, a sealing material used in a conventionally known solar cell module can be applied. For example, ethylene-vinyl acetate copolymer resin (EVA), ionomer, polyvinyl An olefin-based sealing material such as butyral (PVB) or polyethylene can be used.

  Any of the back surface sealing material layers 14 made of these sealing materials can sufficiently mitigate external impacts due to the conventionally known characteristics of impact mitigation.

  In addition to such an effect, the back surface sealing material layer 14 is formed by being laminated with the insulating layer 13, so that the insulating layer 13 as a whole has higher insulation as compared with the case where the insulating layer 13 is disposed alone. The effect of demonstrating sex can be brought about.

  Further, in the present invention, the back surface sealing material layer 14 is formed on the end surface 18 of the solar cell current collector sheet or the end surface 41 of the solar cell module. It plays a role of protecting the interface between the layer 13 and the sealing material layer 14 or the like, or the resin base material 11 and the interface between the sealing material layer 14 and the resin base material 11, and the interface between the resin base material 11 and the back surface protective sheet. ing. Accordingly, as the sealing material for forming the back surface sealing material layer 14, it is more preferable to use an olefin-based sealing material such as polyethylene having a low water absorption rate (low water permeability) and a low water vapor transmission rate.

  The thickness of the back surface sealing material layer 14 is preferably 100 μm or more and 600 μm or less. If the thickness is less than 100 μm, the impact cannot be sufficiently mitigated, and the effect of enhancing the insulation becomes insufficient, which is not preferable. If the thickness exceeds 600 μm, no further effect can be obtained. Pattern formation becomes difficult and uneconomical.

  The color of the back surface sealing material layer 14 is not particularly limited. The material resin is not particularly colored and may remain colorless or translucent, or may be colored in an arbitrary color. For example, it is possible to contribute to improving the power generation efficiency of the solar cell module 40 by reflecting incident light by coloring it in a color having high engagement reflectance such as white, or by coloring it in white or black. The designability of the solar cell module 40 can also be improved.

<Method for producing solar battery collector sheet>
In the method for manufacturing the solar cell current collector sheet 10 of this embodiment, a laminated sheet in which a conductive layer made of a metal such as copper is first laminated on the surface of the resin substrate 11 is used. By performing an etching process and a peeling process on the laminated sheet, the wiring 12 is formed on the solar cell current collector sheet 10. Further, an insulating coating process is performed on the laminated sheet on which the wiring 12 is formed, so that the insulating layer 13 is formed so as to cover the wiring 12, and the sealing material coating process is performed by laminating on the insulating layer 13. As a result, the back surface sealing material layer 14 is formed on the insulating layer 13. Hereinafter, an etching process, a peeling process, an insulating coating, and a sealing material coating process will be described.

[Etching process]
First, the etching process will be described. In this step, an etching mask (not shown) patterned in the shape of a desired wiring 12 is formed on the surface of the above laminated sheet, and then an etching process is performed, so that the conductivity in a portion not covered with the etching mask is obtained. A step of removing the layer.

  As already explained, the laminated sheet used in this step is one in which a conductive layer made of a metal such as copper is formed on the surface of the resin substrate 11. About the method of forming the conductive layer which consists of metals, such as copper, on the surface of the resin base material 11, the method of adhere | attaching copper foil on the surface of the resin base material 11 with an adhesive agent, and vapor-depositing copper foil on the surface of the resin base material 11 Although the method of making it etc. is illustrated, the method of adhere | attaching copper foil on the surface of the resin base material 11 with an adhesive agent is advantageous from the surface of cost. Among these, a method of bonding the copper foil to the surface of the resin base material 11 by a dry laminating method using an adhesive such as urethane, polycarbonate, or epoxy is preferable.

  In this step, first, an etching mask (not shown) patterned in the shape of a desired wiring 12 is formed on the surface of the laminated sheet (that is, the surface of the conductive layer). The etching mask is provided so that the conductive layer to be the wiring 12 is free from corrosion by the immersion liquid in the etching process. A method for forming such an etching mask is not particularly limited. For example, an etching mask is formed on the surface of the laminated sheet by developing a photoresist or a dry film after being exposed to ultraviolet light through the photomask. Alternatively, an etching mask may be formed on the surface of the laminated sheet by a printing technique such as an ink jet printer. The etching mask needs to be able to be stripped with an alkaline stripping solution in a stripping step described later. From such a viewpoint, it is preferable to produce an etching mask using a photoresist or a dry film.

  Next, the etching process in an etching process is demonstrated. This process is a process of removing the conductive layer in a portion not covered with the etching mask with an immersion liquid. By passing through this treatment, portions of the conductive layer other than the portion to be the wiring 12 are removed, so that the conductive layer remains in the desired shape of the wiring 12 on the surface of the resin base material 11. .

[Peeling process]
Next, the etching mask is removed using an alkaline stripping solution in the stripping step. Through this step, the etching mask is removed from the surface of the wiring 12. Examples of the alkaline stripping solution used in the stripping step include an aqueous solution of caustic soda having a predetermined concentration.

[Insulating coating process]
The insulating coating can be performed by a method using a light and / or thermosetting insulating coating agent.

  Specifically, the end face 18 of the solar cell current collector sheet is covered with an ultraviolet curable insulating coating agent so as to cover the wiring 12 forming portion and the wiring non-forming portion of the laminate except the conductive recess 16. When the solar cell module 40 is formed, it is applied to a portion that is not exposed to the end face 41, and then is cured by irradiation with ultraviolet rays to perform an insulating coating. In this case, an ultraviolet curing insulating coating agent such as an acrylic type can be suitably used.

  Application to the end surface 18 of the solar cell current collector sheet and the portion not exposed to the end surface 41 when the solar cell module 40 is made means that the portion that becomes the end surface 18 when the solar cell current collector sheet 10 is used, or the solar cell module What is necessary is just to leave the site | part which does not apply 1 mm or more of insulation coating from the end surface 41 when it is set to 40. If the portion where the insulating coating is not applied is too narrow, the portion which is not applied in the process until the solar cell module 40 is completed is damaged. Insulation is performed on the end surface 18 of the solar cell current collector sheet or the end surface 41 of the solar cell module. The layer 13 and the interface between the insulating layer 13 and the resin base material 11 and the interface between the insulating layer 13 and the sealing material layer 14 cannot be sufficiently protected. Moreover, if it tries to take widely, while the size of the solar cell module 40 will necessarily become large, the area which the solar cell element 30 occupies with respect to the magnitude | size of the solar cell module 40 will fall, and electric power generation per unit area Efficiency will decrease. Actually, since the distance from the end surface 41 of the solar cell module to the nearest solar cell element 30 is generally about 15 mm, the portion where the insulating coating is not applied is the end surface 41 of the solar cell module or the solar cell module. 5 mm to 10 mm from the end face 18 of the battery current collector sheet is suitable.

  Insulating coating can also be performed by a method using other conventionally known insulating agents such as thermosetting insulating ink such as epoxy-phenolic ink.

[Sealing material lamination process]
The method for forming the back surface sealing material layer 14 is not particularly limited. For example, after forming the sealing material in a sheet shape, a through hole is formed in advance at a position where the conductive recess 16 is formed, and then the insulating layer 13 is formed. The insulating layer 13 is laminated in a wider area than the portion where the insulating layer 13 is formed so that the concave portion formed by the step and the through hole overlap with each other and the insulating layer 13 is not exposed to the end face 18. By doing so, the conductive recess 16 penetrating so as to cover the wiring 12 can be formed, and since the sealing material layer 14 is sufficiently soft, the end surface of the insulating layer 13 is covered with the sealing material layer 14.

  At this time, the solar cell current collector sheet 10 according to the second embodiment in which the end surface of the resin base material 11 shown in FIGS. 3 and 4 is covered with the sealing material layer 14, as shown in FIG. When the solar cell module 40 according to the second embodiment in which the end surface of the resin base material 11 is covered with the sealing material layer 14 is used, a sheet obtained by molding the sealant into a sheet shape is laminated when the layers are stacked. It can be easily achieved if it is larger than the size.

<Method for manufacturing solar cell module>
Next, the manufacturing method of the solar cell module 40 which joined the collector sheet 10 for solar cells and the solar cell element 30 which are one Embodiment of this invention is demonstrated.

  As shown in FIG. 5 and FIG. 6, before the step of integrating the solar cell current collector sheet 10, the solar cell element 30 and other members, first, the conductive recess 16 of the solar cell current collector sheet 10 is electrically conductive. Fill material 17. Examples of the conductive material 17 include a conductive paste in which silver and epoxy are mixed. Thereby, since the conductive recess 16 is formed so that the wiring 12 is exposed at the bottom surface, the conductive material 17 and the wiring 12 are electrically connected. More specifically, in FIGS. 5 and 6, the conductive recess 16 connected to the wiring 12 and the first electrode 32 and the conductive recess 16 connected to the wiring 12 and the second electrode 33 are respectively composite layers. Are conducted separately.

  On the one solar cell element 30 side, a back contact solar cell element 30 such as an MWT solar cell element shown in FIGS. 5 and 6 or an EWT solar cell element is used. In the case of the MWT solar cell element 30, the through hole 31 is filled with a silver paste (conductive material 17) as shown in FIGS.

  Next, other members such as the solar cell current collector sheet 10, the solar cell element 30, and the back surface protective sheet 15 are laminated and integrated. 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. or higher and 190 ° C. or lower. The laminating time is preferably in the range of 5 minutes to 60 minutes, and particularly preferably in the range of 8 minutes to 40 minutes.

  In this integration process, since the resin base material 11 of the solar cell current collector sheet 10 is firmly integrated with other members as the solar cell module 40, the base resin of the solar cell current collector sheet 10. Even when heated above Tg, there is no problem of shrinkage or deformation due to heat.

  As a result of the integration described above, as shown in FIG. 4, electricity taken out from the negative electrode of the solar cell element passes through the silver paste in the through-hole 31, passes through the first electrode 32 (negative electrode), and further into the conductive recess 16. It is conducted to the corresponding wiring 12 through the conductive material 17 inside. Further, electricity taken out from the second electrode 33 (positive electrode) can be conducted to the corresponding wiring 12 through the conductive material 17 in the conductive recess 16.

<Other forms of solar cell current collector sheet>
As described above, the solar cell current-collecting sheet 10 becomes a solar cell module 40 through a process of integrating with other members in addition to the solar cell element 30. It is also possible to obtain a solar cell current collector sheet integrated with a back surface protection sheet used for manufacturing a solar cell module by previously integrating another back surface protection sheet 15 such as another ETFE or hydrolysis resistant PET on the light receiving surface side. is there.

  In order to create the above-described back protection sheet-integrated solar cell current collector sheet, a back protection sheet is laminated on the non-light-receiving surface side of the resin substrate 11 by a dry lamination method.

<Example 1>
First, a laminated sheet was prepared by laminating a 20 μm conductive layer made of copper on a surface of a 50 μm film made of polyethylene terephthalate (PET) as a resin base material by dry lamination using a urethane-based adhesive.

  This laminated sheet is cut into 500 mm x 500 mm, a dry film is bonded using a laminator, exposed to ultraviolet rays through a photomask for forming a wiring pattern, and developed with a sodium carbonate aqueous solution to form an etching mask. did. The laminate on which the etching mask was formed was etched with a ferric oxide aqueous solution to form a copper wiring pattern, and then the etching mask was peeled off with a sodium hydroxide aqueous solution.

  As the insulating coating, an acrylic ultraviolet curable insulating coating agent was used, and screen printing was used. Except for the 10 mm portion from the conductive recess 16 and the edge of the laminate, printing was performed in a range of 480 mm × 480 mm, and then ultraviolet rays were applied and cured.

  After forming a sealing material made of polyethylene resin into a sheet shape, it is cut into 500 mm x 500 mm, and a through hole is formed in advance by punching or the like at a position where a conductive recess is to be formed, and then a recess and a penetration formed by an insulating layer Processing was performed using a vacuum heating laminator at 150 ° C. for 18 minutes so that the holes overlap and the insulating layer was not exposed to the end face. Thus, the solar cell current collector sheet of Example 1 was prepared.

<Example 2>
First, a laminated sheet was prepared by laminating a 20 μm conductive layer made of copper on a surface of a 50 μm film made of polyethylene terephthalate (PET) as a resin base material by dry lamination using a urethane-based adhesive.
This laminated sheet is cut into 500 mm x 500 mm, a dry film is bonded using a laminator, exposed to ultraviolet rays through a photomask for forming a wiring pattern, and developed with a sodium carbonate aqueous solution to form an etching mask. did.
The laminate on which the etching mask was formed was etched with a ferric oxide aqueous solution to form a copper wiring pattern, and then the etching mask was peeled off with a sodium hydroxide aqueous solution.

  As the insulating coating, an acrylic ultraviolet curable insulating coating agent was used, and screen printing was used. Except for the 10 mm portion from the conductive recess 16 and the edge of the laminate, printing was performed in a range of 480 mm × 480 mm, and then ultraviolet rays were applied and cured.

After forming a sealing material made of polyethylene resin into a sheet shape, it is cut into 510 mm x 510 mm, and a through hole is formed in advance by punching or the like at a position where a conductive recess is to be formed, and then a recess and a penetration formed by an insulating layer Processing is performed using a vacuum heating laminator at 150 ° C. for 18 minutes so that the hole overlaps, the insulating layer is not exposed at the end face, and the end face of the resin base material is covered with the sealing material layer. It was. Thus, the solar cell current collector sheet of Example 2 was prepared.
<Example 3>
First, a laminated sheet was prepared by laminating a 20 μm conductive layer made of copper on a surface of a 50 μm film made of polyethylene terephthalate (PET) as a resin base material by dry lamination using a urethane-based adhesive.
This laminated sheet is cut into 500 mm x 500 mm, a dry film is bonded using a laminator, exposed to ultraviolet rays through a photomask for forming a wiring pattern, and developed with a sodium carbonate aqueous solution to form an etching mask. did.
The laminate on which the etching mask was formed was etched with a ferric oxide aqueous solution to form a copper wiring pattern, and then the etching mask was peeled off with a sodium hydroxide aqueous solution.

  The insulating layer was formed by screen printing using an acrylic ultraviolet curable insulating coating agent. Except for the 10 mm portion from the conductive recess 16 and the edge of the laminate, printing was performed in a range of 480 mm × 480 mm, and then ultraviolet rays were applied and cured.

  The laminated body in which the insulating layer was formed was bonded together by the dry lamination in the center part of the back surface protection sheet 510mm * 510mm which consists of ETFE prepared beforehand.

<Creation of solar cell module>
After forming a sealing material made of polyethylene resin into a sheet shape, it is cut into 510 mm x 510 mm, and a through hole is formed in advance by punching or the like at a position where a conductive recess is to be formed, and then a recess and a penetration formed by an insulating layer Processing is performed using a vacuum heating laminator at 150 ° C. for 18 minutes so that the hole overlaps, the insulating layer is not exposed at the end face, and the end face of the resin base material is covered with the sealing material layer. It was. In this manner, a current collector sheet for solar cell integrated with a back surface protective sheet of Example 3 was prepared.

A conductive paste in which silver and epoxy were mixed as a conductive material was formed in the conductive recesses of the solar cell current collector sheets of Example 1 to Example 3. Thereby, it was confirmed that the conductive material and the wiring were electrically connected.

  Next, on the surface of the solar cell current collector sheet 10 in which the conductive material 17 is formed in the conductive recess 16, an MWT solar cell element 30, a surface sealing material layer 24, a transparent front substrate 25 made of glass, and an implementation. About Example 1 and Example 2, the back surface protection sheet 15 was laminated | stacked on the back surface, and the solar cell module was produced by integrating on 150 degreeC and the conditions for 18 minutes by a vacuum heat lamination process.

  The solar cell module produced using the solar cell current collector sheet of Example 1 to Example 3 was subjected to a test for 3500 hours in an environment of temperature 85 ° C. and humidity 85% RH. There was no exfoliation, and it showed excellent durability.

  By improving the weather resistance, water resistance, and water vapor barrier properties of the end face 18 of the solar cell current collector sheet 10, a long-life solar cell module 40 and further a solar cell panel can be realized.

10 (for solar cell) current collector sheet 11 resin base material 12 wiring 13 insulating layer 14 (back surface) sealing material layer 15 back surface protective sheet 16 conductive recess 17 conductive material 18 end surface 24 (of solar cell current collector sheet) Surface) Sealing material layer 25 Transparent front substrate 30 Solar cell element 31 Through hole 32 (First) electrode 33 (Second) electrode 40 Solar cell module 41 (Solar cell module) End surface

Claims (5)

  For the internal wiring in the solar cell module, it is arranged on the non-light-receiving surface side of the back contact type solar cell element, is formed on a part of the surface of the resin base material, covers the wiring and the wiring made of a conductor An insulating layer to be formed, and a sealing material layer formed on the insulating layer, and the insulating layer and the sealing material layer on the wiring are connected to the insulating layer and the sealing material layer via the insulating layer and the sealing material layer. A conductive recess is formed to expose the wiring in order to connect the electrode on the non-light-receiving surface side of the solar cell element and the wiring corresponding thereto, and the end surface of the insulating layer is covered with the sealing material layer. A solar cell current collector sheet characterized by the above.   For the internal wiring in the solar cell module, it is arranged on the non-light-receiving surface side of the back contact type solar cell element, is formed on a part of the surface of the resin base material, covers the wiring and the wiring made of a conductor An insulating layer to be formed, and a sealing material layer formed on the insulating layer, and the insulating layer and the sealing material layer on the wiring are connected to the insulating layer and the sealing material layer via the insulating layer and the sealing material layer. A conduction recess is formed in which the wiring is exposed in order to conduct the electrode on the non-light-receiving surface side of the solar cell element and the wiring corresponding thereto, and the end surface of the resin base material is the sealing material layer. The solar cell current collector sheet according to claim 1, wherein the solar cell current collector sheet is covered.   The solar cell current collector sheet according to claim 1, wherein the sealing material layer is a polyethylene-based resin.   The back surface protection sheet integrated sun according to any one of claims 1 to 3, wherein a back surface protection sheet is integrated on a back surface side of the resin base material, and the insulating layer is not exposed. Battery current collector sheet.   A solar cell module using the solar cell current collector sheet according to any one of claims 1 to 4.

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