JP5876226B2 - Solar cell current collector sheet and solar cell module using the same - Google Patents

Description

  The present invention relates to a solar cell current collector sheet based on a resin, and more particularly to a solar cell current collector sheet used as wiring inside a solar cell module and a solar cell module using the same.

  In recent years, solar cells as a clean energy source have attracted attention due to the growing awareness of environmental issues. Generally, a solar cell module constituting a solar cell has a configuration in which a transparent front substrate, a front surface side sealing material sheet, a solar cell element, a back side sealing material sheet, and a back surface protection sheet are laminated in order from the light receiving surface side. Yes, it has a function of generating power when sunlight enters the solar cell element.

  A plurality of solar cell elements that generate power inside the solar cell module are usually provided inside the solar cell module, and are configured to obtain necessary voltages and currents by connecting them in series and parallel. . In order to wire a plurality of solar cell elements inside a solar cell module, for example, a solar cell current collector sheet in which a metal foil that becomes a circuit is laminated on the surface of a resin sheet as a base material is used (Patent Literature). 1).

  The current collecting circuit sheet is a sheet including at least a laminate including a base material such as a resin sheet and a circuit such as a metal foil laminated on the base material. Moreover, when an insulating layer etc. are formed on a circuit, the laminated body containing an insulating layer etc. is also a solar cell current collection sheet. In the solar cell current collector sheet, electricity obtained from the solar cell elements is collected in a current collection box or the like through a circuit.

  By the way, the solar cell element includes a light receiving surface for receiving sunlight and a non-light receiving surface located on the back side thereof. In order to increase the light receiving efficiency of the sunlight on the light receiving surface, electrodes are arranged on the light receiving surface. First, 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-through (EWT) comprising a semiconductor substrate having a plurality of through-holes that penetrate 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 type, there is also a solar cell element having a structure having no through hole. Here, particularly when taking out electricity directly from the electrode of the solar cell element having a through-hole structure, the non-light-receiving surface side element having either positive or negative polarity and the non-light-receiving surface side element arranged on the non-light-receiving surface side element There is a risk of causing a short circuit with the wiring portion corresponding to the electrode having a polarity different from that of the element.

JP 2007-081237 A

  For this reason, in order to take out electricity safely from these back contact type solar cell elements, there is a need for a solar cell current collector sheet that can reliably prevent the short circuit described above when bonded to these solar cell elements. It was done.

  The present invention has been made in view of the situation as described above, and is a solar cell current collector sheet that is disposed on a non-light-receiving surface-side element having a positive or negative polarity and a non-light-receiving surface-side element. It is an object of the present invention to provide a solar cell current collector sheet and a method for manufacturing the same that can reliably prevent a short circuit between wiring elements corresponding to electrodes having a polarity different from that of the non-light-receiving surface side element.

  As a result of intensive studies to solve the above problems, the present inventors pattern-formed an insulating layer having a conductive recess on a circuit that is a conductive portion of a current collector sheet for a solar cell based on a resin. Thus, the inventors have found that the short circuit described above can be surely prevented, and have completed the present invention.

  Moreover, it is desirable from the viewpoint of cost and the like to use a resin such as polyethylene terephthalate (PET) as the base material of the solar cell current collector sheet. However, in a solar cell current collector sheet using a resin having a low glass transition point (Tg) and poor heat resistance as a base material, the curing of the insulating layer made of a thermosetting resin is precured and main cured. It was found that these low Tg substrates can be used by setting the stage. Specifically, the present invention provides the following.

  (1) The present invention is a solar cell current collector sheet in which a circuit comprising a metal wiring portion and a non-wiring portion is formed on the surface of a resin substrate, and an insulating layer is provided on the circuit. The insulating layer on the wiring part is formed, and the wiring is connected to the electrode on the non-light-receiving surface side of the solar cell element and the corresponding wiring part through the insulating layer. It is the solar cell current collection sheet | seat characterized by the conductive recessed part which a part exposes being formed.

  (2) Moreover, this invention is the said conduction | electrical_connection recessed part corresponding to the 1st electrode position formed in the non-light-receiving surface side through a through hole from the light-receiving surface side element of the said solar cell element, and the said sun. It is a current collection sheet for solar cells as described in (1) provided with the 2nd conduction | electrical_connection recessed part corresponding to the 2nd electrode position of the non-light-receiving surface side element of a battery element.

  (3) Moreover, this invention is that the glass transition temperature (Tg) of the resin base material of the said collector sheet for solar cells is 100 degrees C or less, the said insulating layer consists of thermosetting insulating inks, and the said insulating layer is, It is a collector sheet for solar cells according to (1) or (2), which is an uncured insulating ink layer dried by touch at a temperature lower than the glass transition temperature.

  (4) Moreover, this invention is a current collection sheet for solar cells as described in (3) whose said thermosetting type insulation ink is an epoxy-phenol type ink.

  (5) Moreover, this invention is (1) or (2) whose glass transition temperature (Tg) of the resin base material of the said collector sheet for solar cells is 100 degrees C or less, and whose said insulating layer is ultraviolet curable insulating ink. ).

  (6) Moreover, this invention dry-touches the said thermosetting insulation ink in the collector sheet for solar cells as described in (3) or (4) at the temperature below the said glass transition temperature, and modularization process after that In the solar cell module manufacturing method, the thermosetting insulating ink is cured at a temperature at which the glass transition temperature is higher than the glass transition temperature.

  (7) In the present invention, another layer is laminated on the back surface side of the resin base material, and is integrated with the back surface protection sheet. (1) to (5) It is a collector sheet for solar cells.

  (8) Moreover, this invention is a manufacturing method of the collector sheet for solar cells in any one of (1) to (5) or (7), Comprising: After laminating | stacking metal foil on the surface of a resin base material, A method for manufacturing a solar cell current collector sheet comprising: a step of etching a metal foil to form a circuit; and a step of patterning the insulating layer in addition to the conductive recesses of the wiring portion and the non-wiring portion.

  (9) Further, in the present invention, the solar cell current collector sheet according to any one of (2) to (5) or (7) is provided on the non-light-receiving surface side of the solar cell element having an MWT or EWT through hole. A solar cell module comprising a laminated joining member, wherein the solar cell element is composed of a light receiving surface side element and a non-light receiving surface side element, and is formed on the non light receiving surface side from the light receiving surface side element through a through hole. And a second electrode formed on the non-light-receiving surface side element, the conductive recess of the solar cell current collector sheet is filled with a conductive material, One electrode and the conductive material in the first conductive recess are joined so as to conduct, and the second electrode and the conductive material in the second conductive recess are joined so as to conduct It is a battery module.

  (10) Further, according to the present invention, a metal wiring portion and a non-wiring portion are formed on the surface of the resin base material on the non-light-receiving surface side of the solar cell element having an MWT or EWT through-hole through an insulating layer. A solar cell module comprising a non-insulated solar cell current collector sheet on which a circuit is formed, wherein the solar cell is partially connected to the insulating layer via the insulating layer. This is a solar cell module in which a conductive recess in which the wiring part is exposed is formed in order to connect the electrode on the non-light-receiving surface side of the element and the wiring part corresponding thereto.

  (11) Further, in the present invention, the insulating layer is formed in advance on the non-light-receiving surface side of the solar cell element, and then laminated with the current collector sheet for uninsulated solar cells. It is a manufacturing method of a battery module.

  According to the present invention, a solar cell current collector sheet bonded to a solar cell element, the non-light-receiving surface side element having either positive or negative polarity, and the non-light-receiving surface side element disposed on the non-light-receiving surface side element Provided are a solar cell current collector sheet having an insulating layer capable of preventing a short circuit with a wiring portion corresponding to an electrode having a polarity different from that of an element, and a method for producing the same.

It is the perspective view which represented typically the back contact type solar cell element which has a through hole. It is sectional drawing which follows the XX line of FIG. It is the perspective view which represented typically the joining member of the solar cell element and the collector sheet for solar cells of this invention. It is sectional drawing which follows the YY line of FIG. It is the figure which isolate | separated the joining member of FIG. 4 into the solar cell element and the collector sheet for solar cells. It is a graph showing the result of having measured and contrasted about the smoothness after hardening of each of the insulating layer which consists of thermosetting insulating ink, and the insulating layer which consists of ultraviolet curable insulating ink.

  Hereinafter, one embodiment of the current collector sheet for solar cells of the present invention and one embodiment of the method for producing the current collector sheet for solar cells of the present invention will be described.

  First, a back contact solar cell element 1 having a through hole used in an embodiment of the solar cell current collector sheet of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view schematically showing the solar cell element 1. 2 is a cross-sectional view taken along line XX of FIG.

  The solar cell element 1 used in the present embodiment includes a light receiving surface side element 11 having either positive or negative polarity and a non-light receiving surface side element 12 having a polarity different from that of the light receiving surface side element 11. A plurality of through-holes 13 that penetrate the light-receiving surface side element 11 and the non-light-receiving surface side element, and through the through-hole 13 from the light-receiving surface side element 11 to a position immediately below the through hole 13 on the non-light-receiving surface side element 12. A first electrode 41 to be formed and a second electrode 42 formed at a place other than directly below the through hole 13 on the non-light-receiving surface side element 12 are provided. In the back contact type solar cell element, when the polarity of the light receiving surface side element 11 is negative, the first electrode is a negative electrode and the second electrode is a positive electrode, but the polarity of the light receiving surface side element 11 is positive. In this case, the first electrode is a positive electrode and the second electrode is a negative electrode.

  As an example of the back contact type solar cell element 1 having the through hole 13 used in the present embodiment, a metal wrap through (MWT) type or an emitter wrap through (EWT) type solar cell element can be cited. The MWT solar cell element is a solar cell element 1 in which a metal such as silver paste 14 is filled in the through hole 13 and the power collected on the light receiving surface through the metal is taken out from the first electrode 41 on the non-light receiving surface side. A solar cell element having a structure. The EWT solar cell element is a solar cell having a structure in which a diffusion layer is provided on the inner wall of the through hole 13 of the solar cell element 1 and the power collected on the light receiving surface through the diffusion layer is taken out from the first electrode 41 on the non-light receiving surface side. Refers to an element.

In the solar cell element 1 of FIG. 2, when electricity is directly taken out from the electrode 4 using a normal solar cell collector sheet, a non-light-receiving surface side element 12 having either positive or negative polarity and a non-light-receiving surface side element There is a concern about an electrical short circuit with the wiring part 221 corresponding to the first electrode 41 disposed on the non-light-receiving surface side element 12 and having a polarity different from that of the non-light-receiving surface side element 12. In order to solve this problem, an insulating layer having a very high insulation level is formed between the non-light-receiving surface side element 12 having the electrode 4 of the solar cell element 1 and the solar cell current collector sheet. Is the first feature. Here, the high insulation level means that the volume resistance value measured according to JIS C6481 is 10 ⁷ Ω or more, preferably 10 ¹¹ Ω or more. Specifically, when the solar cell current collector sheet 2 of the present invention is joined to the solar cell element 1, the non-light-receiving surface side element 12 and the wiring portion 221 corresponding to the first electrode 41 are reliably insulated. The above-mentioned short circuit can be prevented by providing an insulating layer that can be used and taking out electricity using the solar cell current collector sheet 2.

  With reference to FIGS. 3 to 5, an embodiment of the solar cell current collector sheet 2 of the present invention will be described. FIG. 3 is a perspective view schematically showing the joining member 3 of the back contact solar cell element 1 having the through hole 13 and the solar cell current collector sheet 2 of the present invention. 4 is a cross-sectional view taken along line YY of FIG. FIG. 5 is a diagram in which the joining member 3 of FIG. 4 is separated into a solar cell element 1 and a solar cell current collector sheet 2.

<Current collector sheet for solar cell>
The solar cell current collector sheet 2 of this embodiment includes a resin base material 21, a circuit 22, an insulating layer 23, and a conductive recess 24 formed in a part of the insulating layer 23. A wiring part 221 made of a metal foil such as copper and a circuit 22 made of a non-wiring part 222 are formed on the surface of the resin base material 21. An insulating layer 23 is formed so as to cover the circuit 22. In addition, a conductive recess 24 penetrating from the upper surface of the insulating layer to the upper surface of the circuit is formed.

  The resin base material 21 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 substrate 21 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 resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide resins such as various nylons, polyimide resins, polyamideimide resins Examples thereof include resins, polyaryl phthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyether sulfone resins, polyurethane resins, acetal resins, and cellulose resins.

  According to the present invention, as will be described later, PET having a glass transition temperature (Tg) of 100 ° C. or less can be used as the resin base material 21.

  What is necessary is just to set the thickness of the resin base material 21 suitably according to the intensity | strength, thinness, etc. which are requested | required of the collector sheet 2 for solar cells. Although the thickness of the resin base material 21 is not specifically limited, 20-250 micrometers is mentioned as an example.

  The circuit 22 is an electrical wiring formed on the surface of the solar cell current collector sheet 2 so as to have a desired wiring shape. The wiring part 221 of the circuit 22 is a layer made of a metal foil such as copper. In order to form the circuit 22 on the surface of the resin base material 21, a method of bonding a copper foil to the surface of the resin base material 21, and then patterning the copper foil by etching or the like is exemplified.

  What is necessary is just to set the thickness of the circuit 22 suitably according to the magnitude | size of the electric current resistance requested | required of the collector sheet 2 for solar cells. Although the thickness of the circuit 22 is not particularly limited, an example is 10 to 50 μm.

  As shown in FIG. 4, the conductive recess 24 includes a first conductive recess 241 formed immediately below the first electrode 41 of the solar cell element 1 when the solar cell element 1 and the solar cell current collector sheet 2 are joined. The second conductive recess 242 is formed immediately below the second electrode 42 of the solar cell element 1. The first conductive recess 241 is a hole that has substantially the same shape and area in plan view as viewed from the upper surface side of the solar cell element and penetrates from the upper surface portion of the insulating layer 23 to the upper surface of the wiring portion 221. On the other hand, the second conductive recess 242 is also a hole penetrating the insulating layer 23, but its shape and area may be joined to the second electrode 42 and appropriately designed according to the shape position of the second electrode 42. The

  At the time of joining the solar cell element 1 and the solar cell collector sheet 2, the first conductive recess 241 is formed at a position overlapping the corresponding through hole 13 with the first electrode 41 interposed therebetween, and the second conductive portion 241. The recess 242 is formed at a position directly below the second electrode 42. The space portion between the first conductive recess 241 and the second conductive recess 242 is filled with a conductive material 25 such as solder.

  Since the insulating layer 23 requires the above-mentioned high insulation level, the insulating layer 23 is formed of a thermosetting resin or an ultraviolet curable insulating coating agent. As the thermosetting insulating ink, a conventionally known epoxy-phenol ink is preferable. As the ultraviolet curable insulating coating agent, a conventionally known acrylic coating agent is preferable.

  In order to obtain the high insulation level, the thickness of the insulating layer 23 is preferably 5 μm or more and 25 μm or less. If the thickness is less than 5 μm, the insulating properties are insufficient, which is not preferable. If the thickness exceeds 25 μm, no further effect can be obtained. Rather, it is difficult to form a pattern by applying the conductive recess 24, and it is not economical. Absent.

<Method for producing solar battery collector sheet>
Next, the insulating layer 23 formed on the circuit 22 will be described mainly with reference to FIG. The insulating layer 23 is formed by coating the wiring portion 221 and the non-wiring portion 222 of the circuit 22 and coating with a thermosetting insulating ink. However, the conductive recess 24 is formed without coating the portion where the conductive recess 24 is formed.

  In the manufacturing method of the solar cell current collector sheet 2 of this embodiment, a laminated sheet is used in which a conductive layer made of a metal foil such as copper is laminated on the surface of the resin base material 21. By performing an etching process and a peeling process on the laminated sheet, a circuit 22 is formed on the solar cell current collector sheet 2. Furthermore, an insulating layer 23 is formed on the circuit 22 by applying an insulating coating process to the laminated sheet on which the circuit 22 is formed. Hereinafter, an etching process, a peeling process, and an insulating coating process will be described.

[Etching process]
First, the etching process will be described. In this process, an etching mask (not shown) patterned in the shape of a desired circuit 22 is formed on the surface of the 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 described, the laminated sheet used in this step is one in which a conductive layer made of a metal foil such as copper is formed on the surface of the resin base material 21. About the method of forming the conductive layer which consists of metal foils, such as copper, on the surface of the resin base material 21, the method of adhere | attaching copper foil on the surface of the resin base material 21 with an adhesive agent, copper foil on the surface of the resin base material 21 Although the method of vapor deposition etc. is illustrated, the method of adhere | attaching copper foil on the surface of the resin base material 21 with an adhesive agent is advantageous from the surface of cost. Among these, a method of adhering the copper foil to the surface of the resin substrate 21 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 portion 221 is formed on the surface of the laminated sheet (that is, the surface of the conductive layer). In the etching process, the etching mask is provided so that the conductive layer that will become the wiring portion 221 in the future is free from corrosion by the immersion liquid. The method for forming such an etching mask is not particularly limited. For example, the etching mask may be formed on the surface of the laminated sheet by developing a photoresist or a dry film after exposure through the photomask, An etching mask may be formed on the surface of the laminated sheet by a printing technique such as an inkjet 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. Through this treatment, the conductive layer is removed from the conductive layer except for the portion to be the wiring part 221, so that the conductive layer remains in the desired shape of the wiring part 221 on the surface of the resin base material 21. become.

[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 portion 221. 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 is performed by applying a thermosetting insulating ink so as to cover a portion of the wiring portion 221 and the non-wiring portion 222 of the circuit 22 excluding the conductive recess 24, and then heating and curing the ink. As the thermosetting insulating ink, the above-mentioned epoxy-phenolic ink is preferable. An ultraviolet curable insulating coating agent can also be used for the insulating coating, which will be described later.

  Here, in order to crosslink and cure a thermosetting insulating ink such as an epoxy-phenol-based ink, it is necessary to heat the thermosetting insulating ink to a crosslinking proceeding temperature, for example, around 150 ° C. However, when such heating is performed, when polyethylene terephthalate (PET) or the like is used as a material, the resin substrate 21 of the solar cell current collector sheet 2 exceeds the Tg (glass transition temperature) of the resin base material 21 and contracts and deforms due to the heat. Problem arises. For this reason, it is necessary to use polyethylene naphthalate (PEN) having a higher Tg, but PEN is expensive.

  Therefore, in the present invention, the thermosetting insulating ink is finger-dried at a temperature lower than Tg of the resin base material 21 of the solar cell current collector sheet 2, preferably at a temperature of, for example, 70 ° C. Thus, if it is heating below Tg, the resin base material 21 of the collector sheet 2 for solar cells will not shrink | contract and deform | transform by heat. For this reason, a PET base material can be used as the resin base material 21. Further, although the thermosetting insulating ink is not cured by this touch drying, no tack is generated, so that it can be wound and stored. That is, at this stage, the solar cell current collector sheet 2 is a first stage finished product that can be distributed. In addition, the finger touch drying as used in the present invention is preliminary drying in which the fingertip is lightly touched with the fingertip so that the fingertip is not soiled as defined in JIS K5600-1-1.

  If the Tg of the resin base material 21 is sufficiently high as 100 ° C. or higher, the resin base material 21 may be completely thermoset by applying a temperature up to the crosslinking temperature at this stage. As such a resin base material 21, polyimide (PI) other than said PEN is mentioned, for example.

  Next, the case where ultraviolet curable insulating ink (ultraviolet curable insulating coating agent) is used for the insulating coating will be described. In this case, the ultraviolet curable insulating coating agent is applied by covering the portions of the wiring portion 221 and the non-wiring portion 222 of the circuit 22 excluding the conductive recess 24, and then irradiating it with ultraviolet rays to cure. . As the ultraviolet curable insulating coating agent, the above acrylic coating agent is preferable.

  In this case, since the ultraviolet irradiation does not involve a heat treatment to the resin base material 21, the problem of heat shrinkage of the resin base material 21 does not occur. For this reason, a PET substrate having a Tg of 100 ° C. or less can be suitably used. Also, as a process, ultraviolet curing is shorter in curing time and more economical than thermal curing, and therefore, by using an ultraviolet curable insulating coating agent as a coating agent for forming the insulating layer 23, a solar cell is obtained. The productivity of the current collector sheet or solar cell module can be increased.

<Method for manufacturing solar cell module>
Next, the manufacturing method of a solar cell module provided with the junction member 3 which joined the current collector sheet 2 for solar cells and the solar cell element 1 which are one Embodiment of this invention is demonstrated.

  As shown in FIG. 5, before the step of integrating the solar cell current collector sheet 2, the solar cell element 1 and other members, first, a conductive material 25 is applied to the conductive recess 24 of the solar cell current collector sheet 2. Fill. Examples of the conductive material 25 include a conductive paste such as solder. Thereby, since the conductive recess 24 is formed so that the wiring part 221 is exposed on the bottom surface, the conductive material 25 and the wiring part 221 are electrically connected. More specifically, in FIG. 5, the first conductive recess 241 connected to the wiring portion 221 and the first electrode 41 and the second conductive recess 242 connected to the wiring portion 221 and the second electrode are respectively an insulating layer. 23 are separately conducted.

  On the one solar cell element 1 side, a back contact type solar cell element such as an MWT type solar cell element shown in FIG. 5 or an EWT type solar cell element is used. In the case of an MWT solar cell element, the through hole 13 is filled with a silver paste 14 as shown in FIG.

  Next, the solar cell current collector sheet 2, the solar cell element 1, and other members such as a back surface protection sheet (not shown) 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 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, when the insulating layer 23 is formed using a thermosetting insulating ink, and the solar cell current collector sheet 2 is only preliminarily dried in advance, other members are used. At the same time, heating is performed at a temperature equal to or higher than the crosslinking temperature of the thermosetting insulating ink, for example, 130 ° C. or more, whereby a crosslinking is formed in the thermosetting insulating ink applied to the circuit 22 and curing occurs. At this stage, a hardened insulating layer 23 covering the circuit 22 is formed. In this integration step, the resin base material 21 of the solar cell current collector sheet 2 is firmly integrated with other members as a solar cell module. Even when heated at Tg or higher of the material resin, there is no significant problem of shrinkage or deformation due to heat.

  Here, the insulating layer 23 is required to have adhesiveness with the solar cell element 1 in the solar cell module, that is, high smoothness. FIG. 6 shows an insulating layer (referred to as insulating layer 1) formed using a thermosetting insulating ink (epoxy-phenol type, manufactured by Taiyo Ink, S-500 F534 / HD-50 F534 two-component type), and ultraviolet rays. It is a graph showing the result of having measured the smoothness of each insulating layer (it is set as the insulating layer 2) formed using curable insulating ink (Acrylic, the product made from a solar ink, UVR-182E). The measurement is performed by coating each insulating layer with a thickness of 20 μm on a PET base material having a Tg of 100 ° C., the insulating layer 1 is heat-treated at 150 ° C. for 30 minutes, and the insulating layer 2 is subjected to an ultraviolet treatment of 1000 mJ / cm 2. After each was cured, the PET substrate was placed on a smooth table, and the displacement of the height of the insulating layer surface was measured with a dial gauge. Regarding the displacement of the height, the height of the surface of the insulating layer in the part where each insulating layer is in contact with the above-mentioned smooth base was set to the reference value 0.

  As shown in FIG. 6, the insulating layer made of thermosetting insulating ink exhibits a maximum displacement of about 5 mm, whereas the insulating layer made of ultraviolet curable coating agent has a height displacement of 0. It is understood that the insulating layer made of the ultraviolet curable coating agent is superior in smoothness in a state where the thickness is within about 5 mm and the insulating layer is formed after finishing the curing process.

  As shown in Table 1, the insulating layer formed using the ultraviolet curable insulating coating agent has a thermal contraction in the case of undergoing the above integration process as compared with the insulating layer formed using the thermosetting insulating ink. The rate is small. From this, in the process of integration of the solar cell module, the insulating layer formed using the ultraviolet curable insulating coating agent is better than the insulating layer formed using the thermosetting insulating ink. It turns out that it has smoothness.

  Thus, in the stage where the integration as a solar cell module is finished, the solar cell current collector sheet 2 of the present invention is short-circuited between the non-light-receiving surface side element 12 and the wiring part 221 corresponding to the first electrode 41. Insulating layer 23 that can prevent this is provided, and the above-described high insulation level is provided.

  As a result of the above integration, as shown in FIG. 4, electricity generated in the light-receiving surface side element is taken out from the first electrode 41 through the silver paste 14 in the through hole 13, and is further conductive in the first conduction recess 241. Conductive material 25 is conducted to corresponding wiring part 221 through conductive material 25. In addition, the electricity generated in the non-light-receiving surface side element 12 is taken out from the second electrode 42 and can be conducted to the corresponding wiring part 221 through the conductive material 25 in the second conduction recess 242.

<Other Examples of Current Collection Sheet for Solar Cell>
As described above, the solar cell current collector sheet 2 becomes a solar cell module through a process of integrating with other members in addition to the solar cell element 1, but prior to the process, the back side of the resin base material 21. It is also possible to obtain a back surface integrated sheet used for manufacturing a solar cell module by previously integrating a back surface protective layer (not shown) such as another ETFE or water resistant PET.

  In order to create the above-described back integrated sheet, a back protective sheet is laminated on the back side of the resin base material 21 by a thermal lamination method.

  In addition, regarding the formation of the insulating layer in the manufacturing process of the solar cell module, in addition to the above method, the insulating layer 23 is formed in advance on the non-light-receiving surface side of the solar cell element 1 and then the solar cell current collector is formed. A method of laminating with the sheet 2 can also be taken.

  As described above, the solar cell current collector sheet 2 of the present invention insulates between the non-light-receiving surface side element 12 and the wiring portion corresponding to the first electrode 41 when bonded to the solar cell element 1. The above-described short circuit can be prevented by using the solar cell current collector sheet 2 for taking out electricity from the solar cell element 1.

DESCRIPTION OF SYMBOLS 1 Solar cell element 13 Through hole 2 Current collection sheet for solar cells 21 Resin base material 22 Circuit 23 Insulating layer 24 Conductive recessed part 3 Joining member 4 Electrode 41 1st electrode 42 2nd electrode

Claims (6)

On the surface of the resin base material, a current collector sheet for a solar cell in which a circuit comprising a metal wiring part and a non-wiring part is formed,
An insulating layer is formed on the circuit;
In the insulating layer on the wiring part, a space part where the wiring part is exposed in order to connect the electrode on the non-light-receiving surface side of the solar cell element and the corresponding wiring part through the insulating layer. And a conductive recess that is not filled with a conductive material is formed,
For solar cells, wherein the resin substrate has a glass transition temperature (Tg) of 100 ° C. or less, the insulating layer is made of thermosetting insulating ink, and the insulating layer is a finger-dried uncured insulating ink layer Current collector sheet.   The solar cell current collector sheet according to claim 1, wherein the thermosetting insulating ink is an epoxy-phenolic ink. On the surface of the resin base material, a current collector sheet for a solar cell in which a circuit comprising a metal wiring part and a non-wiring part is formed,
An insulating layer is formed on the circuit;
In the insulating layer on the wiring part, a space part where the wiring part is exposed in order to connect the electrode on the non-light-receiving surface side of the solar cell element and the corresponding wiring part through the insulating layer. And a conductive recess that is not filled with a conductive material is formed,
The solar cell current collector sheet, wherein the resin base material of the solar cell current collector sheet has a glass transition temperature (Tg) of 100 ° C. or lower, and the insulating layer is an ultraviolet curable insulating ink. As the conduction recess,
A first conducting recess corresponding to a first electrode position formed on the non-light-receiving surface side through a through hole from the light-receiving surface side element of the solar cell element;
A second conduction recess corresponding to the second electrode position of the non-light-receiving surface side element of the solar cell element;
A solar cell current collector sheet according to claim 1, comprising:   The current collecting sheet for back surface integrated solar cells according to any one of claims 1 to 4, wherein another layer is laminated on the back surface side of the resin base material and integrated with the back surface protection sheet. It is a manufacturing method of the current collection sheet for solar cells in any one of Claims 1-5,
After laminating the metal foil on the surface of the resin substrate, etching the metal foil to form a circuit;
And a step of patterning the insulating layer in addition to the conductive recesses of the wiring part and the non-wiring part.

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