JP2014197700A - Solar cell unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell unit which reduces usage of expensive material, simplifies manufacturing processes, improves module efficiency, and has light weight.SOLUTION: A solar cell unit comprises: a plurality of solar cells 4 with a conduction member 5 disposed in a flush manner; connection members 6 electrically connecting the solar cells 4 each other; and a filler layer 3 protecting at least a light receiving surface side (upper side) of the solar cells 4. In the solar cell unit, a film-like light transmissive resin layer 10, which has characteristics different from the filler layer 3, is appended on light receiving surfaces of the solar cells 4 and below the filler layer 3. Preferably, embossment patterns are formed on the film-like light transmissive resin layer 10.

Description

  The present invention relates to a solar cell unit and a solar cell module. In the present specification, a solar cell module is a module in which a solar cell unit is incorporated in a frame.

  Research and development of solar cells have been actively conducted as a means of supplying clean and non-depleted energy. Among them, a solar cell in which amorphous silicon is laminated on a silicon single crystal, a silicon polycrystal, or a silicon single crystal is currently the mainstream because of its excellent power generation efficiency.

FIG. 5 shows a schematic cross-sectional view of a currently mainstream crystalline solar cell unit and a solar cell module in which it is incorporated into a frame.
A plurality of solar cells 4a, 4b with conductive materials (solder) 5a, 5b are electrically connected by a connecting member (solder-plated copper ribbon, etc.) 6 through the conductive material 5 (5a, 5b). In order to protect them, it is sealed with a filler layer 3 (3a, 3b) such as ethylene vinyl acetate copolymer (EVA) which is advantageous in terms of light transmittance and cost. Further, a tempered glass 2 whose bottom surface is embossed is laminated on the surface side (upper side), and an antireflection film 1 made of MgF ₂ or the like is further formed thereon by a method such as sputtering or baking. Then, on the back surface side, a back surface protective material (usually polyvinylidene fluoride resin) 7 and a back surface support plate (usually steel plate or tempered glass plate) 8 are laminated to form a solar cell unit (FIG. 5B). Note that the same material is usually used for the filler layers 3a and 3b, and finally, one filler layer 3 is formed.

  Next, the solar cell unit is fitted into the aluminum frame 9 prepared in advance to complete the solar cell module. At this time, the strength of the central portion is insufficient depending on the size of the solar battery cell, so that the reinforcing aluminum frame 9a is often provided in a protective manner.

  By the way, the difficulty of the solar cell module is that it still costs. In order for solar cells to become more widespread, the cost of members to be used and the cost of manufacturing processes must be further reduced (see Non-Patent Document 1 above).

  In addition, many researchers and companies are actively making efforts and improvements for further cost reduction of solar cell modules. For example, in Patent Document 1, a transparent organic polymer resin (EVA or the like) impregnated with a fibrous inorganic compound having irregularities with a predetermined pitch is placed on the light incident side of a photovoltaic element to provide a transparent We are proposing solar cell modules that can withstand long-term outdoor use by preventing dirt from adhering to organic polymer resins.

JP-A-9-191115

Yasuhiro Sasakawa, “Solar Power Generation”-Latest Technology and System, 2000, CMC Corporation

The present mainstream solar cell modules described above have the following problems.
(1) Embossing on the tempered glass plate 2 to efficiently use incident sunlight increases the number of manufacturing steps.
(2) EVA used for the filler layer 3 is hydrolyzed to generate an acid component during the process or in a long-term outdoor exposure, and easily corrodes an electrical connection portion or the like (poor durability).

(3) As the conductive material (solder) 5 provided on the solar battery cell 4, lead-free solder is often used instead of ordinary solder in recent years from the environmental viewpoint. Such a lead-free solder has a higher melting point (about 260 ° C.) than conventional solder and needs to be heated above that temperature. Therefore, the solder peripheral material must withstand a high temperature. With widespread use, there are significant restrictions on the solder peripheral materials. Furthermore, since lead-free solder material including ordinary solder is very easy to flow once it is melted, depending on the process, the solder flows too much to reduce the area receiving sunlight.

(4) The polyvinylidene fluoride resin (back surface protective material) 7 used for the purpose of protecting the solar battery cell or preventing moisture absorption from the back surface thereof is expensive.
(5) In order to reduce the reflection of sunlight and increase the power generation efficiency, the film formation of the antireflection film 1 made of a metal thin film such as MgF ₂ applied on the surface of the tempered glass plate 2 is performed by sputtering or baking raw material inorganic materials. Therefore, high-temperature heat treatment is necessary, and the raw material inorganic material used is expensive.
(6) In order to ensure the strength to withstand stresses such as torsion, a back support plate 8 such as a steel plate or tempered glass is used, or an aluminum frame 9 or a reinforced aluminum frame 9a is used. This has led to an increase in weight.

  The present invention solves these problems, in other words, reduces the use of expensive materials, simplifies the manufacturing process, improves module efficiency, and further reduces the weight of the solar cell unit and It is to provide a solar cell module.

  Since the problems described above are related to each other, it is not always a good idea to solve them by improving a single member or a part of a process. This is because changing some members necessitates changing other members. Conversely, it seems to be a good idea to draw a particular advantage with a number of related members. From such a viewpoint, the present inventor made various studies and completed the following invention. That is, the present invention includes the following several inventions.

As shown in FIG. 1, the first invention has a plurality of solar cells with a conductive material 5 (a plurality of solar cells are usually arranged in a plane on a plane) 4 (4a, 4b) And a solar cell unit comprising a connecting member 6 that electrically connects the solar cells 4 and a filler layer 3 that protects at least the light receiving surface side (upper side) of the solar cells 4. A light-transmitting resin layer 10 having a property different from that of the filler layer 3 is further formed on the light receiving surface (and below the filler layer 3). It is.
In the first invention, as shown in FIG. 2, the photovoltaic power generation efficiency is improved without the embossed pattern (fine uneven pattern) in the film-like light-transmitting resin layer 10, but the embossed pattern (fine uneven pattern) ) Is preferable.

As shown in FIG. 3, the second invention includes a plurality of solar cells 4 with a conductive material 5, a connection member 6 that electrically connects these solar cells 4, and at least light reception of the solar cells 4. In a solar cell unit comprising a filler layer 3 for protecting the surface side, a film-like light transmissive resin layer 10 provided with an embossed pattern capable of diffusing incident light on the upper surface of the filler layer 3 is further provided. It is the solar cell unit characterized by being formed.
Here, the embossed pattern may be provided on one side or both sides of the film-like light transmissive resin layer 10. Select from the viewpoint of workability and workability (usually only one side). Moreover, when giving an embossed pattern only to one side, the embossed pattern surface may be either the upper surface or the lower surface of the film-form light-transmitting resin layer 10. This is also determined in consideration of workability and workability.

  3rd invention is the filler which protects the several photovoltaic cell 4 with the electrically conductive material 5, the connection member 6 which electrically connects these photovoltaic cells 4, and the light-receiving surface side of the photovoltaic cell 4 at least. In the solar cell unit including the layer 3, the filler layer 3 is a resin containing a thermosetting resin and / or a UV curable resin, and the light transmittance at the total energy of the wavelength of 400 to 1100 nm is a weighted average. It is a solar cell unit characterized by being a transparent resin layer of 80% or more (in terms of integral value).

  4th invention is the filler which protects the several photovoltaic cell 4 with the electrically conductive material 5, the connection member 6 which electrically connects these photovoltaic cells 4, and the light-receiving surface side of the photovoltaic cell 4 at least. In the solar cell unit including the layer 3, the conducting material 5 is a solar cell unit including a polymer resin and a conductive adhesive and a film adhesive having anisotropic conductivity.

  As shown in FIGS. 1 and 2, the fifth invention includes a plurality of solar cells 4 with a conductive material 5, a connection member 6 that electrically connects these solar cells 4, and at least the solar cells 4. In the solar cell unit provided with the filler layer 3 for protecting the light receiving surface side, a film-like cell back surface support layer 11 made of an organic polymer resin is further formed on the back surface (lower surface) side of the solar cell 4. It is the solar cell unit characterized by the above.

  In the first to fifth inventions, a light-transmitting surface member 2 made of glass or transparent resin is usually laminated on the upper side of the filler layer 3.

  In addition, the first to fifth inventions and other inventions described above can be combined with any two or more of these inventions to construct a solar cell unit. A solar cell unit can also be constructed by combining the invention.

  As shown in FIG. 4, the present invention also relates to a solar cell module in which the solar cell unit is housed in a molded resin frame 15. Here, the gap between the solar cell unit and the molded resin frame 15 is usually sealed with a sealing resin 16.

Hereinafter, the present invention will be described in more detail.
The material of the film-like light transmissive resin layer 10 in the first invention is preferably a transparent resin having photocurability or thermosetting properties because it is easy to work and has high productivity. The light refractive index in the film-like light transmissive resin layer 10 formed on the light receiving surface of the solar battery cell 4 is preferably larger than the light refractive index in the filler layer 3. However, even if there is no emboss pattern in the film-like light-transmitting resin layer 10 (it is preferable), the photovoltaic power generation efficiency is improved. If the film-like light-transmitting resin layer 10 is provided so as to be in contact with the light receiving surface of the solar battery cell 4, the reason why the photovoltaic power generation efficiency is improved without an embossed pattern is not known. It is estimated that it will be introduced efficiently within.

In addition, when forming an embossed pattern on one side of the film-like light-transmitting resin layer 10 together with the formation of the film-like light-transmitting resin layer 10 on the light-receiving surface of the solar battery cell 4, for example, as follows. Do it.
(I) A transparent resin (semi-cured state) having photocurability or thermosetting property is laminated on one surface of the solar battery cell 4.
(Ii) The embossed mold of fine unevenness is pressed against the laminated resin side, and the fine uneven pattern is transferred to the resin side.
(Iii) The resin is cured by light irradiation or heat treatment, and the transferred embossed pattern is fixed.

  Here, when a photocurable resin is used as the material resin of the film-like light transmissive resin layer 10, instead of using a mold with an embossing, a transparent plastic film with an embossed pattern is used as a mold as it is, It can also be photocured to give an embossed pattern.

  In the first invention, when the embossed pattern (usually one side) is applied when the film-like light transmissive resin layer 10 is formed on the light receiving surface of the solar battery cell 4, the uneven pattern has an uneven pitch of 0.5. The height difference is preferably 0.5 to 1000 μm, more preferably 1 to 100 μm in pitch, and 1 to 100 μm in height difference. Here, the shapes and pitches of the individual irregularities are not necessarily uniform, and may be random.

  Moreover, in 1st invention, the light refractive index in the film-form light-transmitting resin layer 10 is larger than the light refractive index in the filler layer 3 (that is, the layer closer to the solar battery cell 4 is It is devised so that it is larger than the optical refractive index of the layer farther from the solar battery cell 4.

  Also for the material resin of the film-like light transmissive resin layer 10 in the second invention, the photocurable resin or the thermosetting resin is transparently cured by light or heat because the work is easy and the productivity is high. New resin is preferably used.

  In the second invention, when the embossed film-shaped light transmissive resin layer 10 is formed between the filler layer 3 and the light transmissive surface member 2, the thickness of the film-shaped light transmissive resin layer 10 is as follows. Is preferably 0.5 to 2000 μm, more preferably 0.5 to 500 μm, and particularly preferably 0.5 to 200 μm in terms of light diffusion and reduction of absorption loss. The light transmittance of the film-like light transmissive resin layer 10 is preferably as much as possible through 300 to 1200 nm.

  Here, it is preferable that the light refractive index in the film-like light transmissive resin layer 10 is smaller than the light refractive index in the filler layer 3. In other words, the layer closer to the solar battery cell 4 is devised so as to be larger than the refractive index of the layer farther from the solar battery cell 4.

  Examples of the material resin of the film-like light transmissive resin layer 10 include acrylic resin, epoxy resin, PC (polycarbonate), TAC (triacetyl cellulose), PET (polyethylene terephthalate), PVA (polyvinyl alcohol), and PVB (polyvinyl butyral) ), PEI (polyetherimide), polyester, EVA (ethylene-vinyl acetate copolymer), PCV (polyvinyl chloride), PI (polyimide), PA (polyamide), PU (polyurethane), PE (polyethylene), PP (polypropylene) ), PS (polystyrene), PAN (polyacrylonitrile), butyral resin, ABS (acrylonitrile-butadiene-styrene copolymer), ETFE (ethylene-tetrafluoroethylene copolymer), PVF ( Fluorine resins such as vinyl fluoride), silicon resins, and resin compositions obtained by imparting thermosetting or UV curing properties to them, among which acrylic resins, fluororesins, and PU are thermosetting or UV curable. Is preferred in terms of transparency, reliability, and processability. Moreover, it is preferable to add suitably an ultraviolet absorber, a light stabilizer, antioxidant, and a silane coupling agent in resin. As these additives, known ones (for example, those described in JP-A-9-191115) can be used.

  As described above, the material resin of the filler layer 3 in the third invention is a resin containing a thermosetting resin and / or a UV curable resin, and the light transmittance with respect to the total energy at a wavelength of 400 to 1100 nm is weighted. A transparent resin having an average (ie, integral value) of 80% or more is preferable. However, a resin different from the resin used in the film-like light transmissive resin layer 10 is used. Examples of the resin include acrylic resin, epoxy resin, PC (polycarbonate), TAC (triacetyl cellulose), PET (polyethylene terephthalate), PVA (polyvinyl alcohol), PVB (polyvinyl butyral), PEI (polyetherimide), and polyester. , EVA (ethylene-vinyl acetate copolymer), PCV (polyvinyl chloride), PI (polyimide), PA (polyamide), PU (polyurethane), PE (polyethylene), PP (polypropylene), PS (polystyrene), PAN (poly Fluoronitrile resins such as acrylonitrile), butyral resin, ABS (acrylonitrile-butadiene-styrene copolymer), ETFE (ethylene-tetrafluoroethylene copolymer), PVF (polyvinyl fluoride) Silicone resins, or these resin composition imparted with thermosetting or UV-curable, and among these acrylic resins, fluorocarbon resins or PU is preferred in terms of transparency and an reliability.

The polymer resin of the film adhesive (conductive material) having anisotropic conductivity including the polymer resin and conductive particles used in the fourth invention preferably contains an acrylic polymer and a thermosetting resin. Resin. The conductive particles are preferably dispersed in an amount of 10 to 1,000,000 per 1 cm ² (area in plan view) of the connection terminals.
Such a film-like adhesive can obtain electrical conductivity by thermocompression bonding at a temperature of about 150 ° C. or lower, which is lower than that of solder. Therefore, the adhesive of the member on the cell light receiving surface often seen during soldering is obtained. While avoiding yellowing, work efficiency can be improved and manufacturing cost can be reduced. Moreover, the range of selection of a member can be expanded.

  Examples of the material resin for the film cell back support layer 11 used in the fifth invention include acrylic resin, epoxy resin, PC (polycarbonate), TAC (triacetyl cellulose), PET (polyethylene terephthalate), and PVA (polyvinyl alcohol). , PVB (polyvinyl butyral), PEI (polyetherimide), polyester, EVA (ethylene-vinyl acetate copolymer), PCV (polyvinyl chloride), PI (polyimide), PA (polyamide), PU (polyurethane), PE (polyethylene) ), PP (polypropylene), PS (polystyrene), PAN (polyacrylonitrile), butyral resin, ABS (acrylonitrile-butadiene-styrene copolymer), ETFE (ethylene-tetrafluoroethylene copolymer) ), Fluororesins such as PVF (polyvinyl fluoride), silicon resins, or resin compositions that have been provided with thermosetting or UV curable properties. Among them, acrylic resins, fluororesins, PU, and the like. A resin composition imparted with thermosetting property or UV curable property is preferable in terms of reliability and workability.

Here, it is preferable that a lower hygroscopic foam layer 13 is formed on the lower side of the film-like cell back surface support layer 11, and more preferably, a reflective film 12 such as a metal thin film is sandwiched. Then, the foam layer 13 is formed. With such a structure, the use of expensive polyvinylidene fluoride can be avoided, and the cost can be reduced.
Moreover, it is preferable that 50% or more of the foam volume of the foam layer 13 is closed cells.

  Further, it is preferable that a reflective film 12 is further formed between the film-like cell back surface support layer 11 and the foam layer 13, and the reflective film 12 is usually a metal thin film of aluminum or an aluminum-containing alloy. preferable.

  In the first to fifth inventions, the light transmissive surface member 2 is usually laminated on the upper side of the filler layer 3. In this case, the light transmissive surface member 2 includes a transparent organic resin plate such as an acrylic plate in addition to glass, tempered glass, and organic glass, and is preferably tempered glass.

When the light transmissive surface member 2 is laminated on the upper side of the filler layer 3, it is preferable to further form the antireflection film 1 on the surface side (upper side) of the light transmissive surface member 2. This is to supply as much external light as possible to the solar cells 4. Here, as the antireflection film 1, an antireflection film such as MgF ₂ which has been conventionally used can be used. Preferably, an organic polymer material, a fluorine-containing organic polymer material, a low temperature is used. It is made from a coating-type material such as a sol-gel material or a polysilazane material. If such a coating-type organic material is used, a simple coating method and low-temperature curing are possible, and it is possible to share with other processes. The thickness of the coating film is preferably 10 to 300 nm. The light refractive index of the antireflection film 1 is preferably smaller than the light refractive index of the light transmissive surface member 2.

  As a method for forming such an antireflection film 1, for example, after being appropriately diluted so as to obtain a film thickness of 10 to 300 nm after curing, a desired film thickness is obtained by a method such as spin coating, spray coating, or dip coating. Among them, spray coating is most preferable in terms of cost. Moreover, when a glass plate is used as the light transmissive surface member 2, it is preferable to appropriately perform primer treatment in order to improve adhesion. In addition, as will be described later, by performing simultaneously with the curing of the last sealing resin of the solar cell module assembly, firing at about 800 ° C. in the case of using a conventional inorganic material becomes unnecessary, and the time required for temperature increase and decrease Shortening and cost reduction of firing energy are possible.

(1) According to the first invention, incident sunlight can be used efficiently. The reason is presumed that incident light is efficiently introduced into the solar cell by refraction of light in the film-like light transmissive resin layer 10 on the light receiving surface of the solar cell 4. Moreover, it becomes unnecessary to give an embossed pattern to the light transmissive surface member 2 such as a tempered glass plate.
(2) According to the second invention, since the embossed pattern in the film-like light transmissive resin layer 10 formed on the upper side of the filler layer 3 diffuses incident sunlight, the incident sunlight can be used efficiently. Moreover, it is simpler to give an embossed pattern to the film-form light-transmitting resin layer 10 as compared with a process to give an embossed pattern to a tempered glass plate.
(3) According to the third invention, since a transparent resin containing a thermosetting resin and / or a UV curable resin is used for the filler layer 3, hydrolysis can be performed during the process or in a long-term outdoor exposure. Therefore, it does not corrode the electrical connection part or the like, and has high durability.

(4) According to the fourth invention, since the conductive material 5 is made of a film-like adhesive that includes a polymer resin and conductive particles and has anisotropic conductivity, as in the case of using solder or lead-free solder. Heating at a high temperature (about 260 ° C. or higher) is not necessary, and therefore the conductive material peripheral material does not need to withstand the high temperature. There are few restrictions on the selection of materials around the conductive material. In addition, when the solder is used, it is difficult for the solar light receiving area to decrease due to excessive melting (overflow) of the solder. In addition, the work is easier than using solder.
(5) According to the fifth invention, a film-like cell back surface support layer 11 made of an organic polymer resin (without using polyvinylidene fluoride resin) is formed on the back surface (lower surface) side of the solar battery cell 4. Therefore, the member cost can be reduced.
(6) A transparent surface member 2 made of glass or transparent resin is laminated on the upper side of the filler layer 3, and an organic polymer material, a fluorine-containing organic polymer material, a low-temperature sol-gel material, or In the case of forming the antireflection film 1 made of a polysilazane-based material, it is not necessary to form an expensive metal thin film such as MgF ₂ (sputtering or firing) on the surface of the tempered glass plate, and therefore no high-temperature heat treatment is required. It becomes. Moreover, the material cost to be used can be reduced.
(7) According to the solar cell module of the present invention, since the molded resin frame 15 is used instead of using the aluminum frame or the reinforced aluminum frame, it can be made relatively light and the material cost can be reduced.

It is a solar cell unit of the 1st example concerning the present invention, (b) is a longitudinal section and (a) is the exploded view. The exploded view of the solar cell unit of the 2nd example concerning the present invention. It is a solar cell unit of the 3rd example concerning the present invention, (b) is a longitudinal section and (a) is the exploded view. Explanatory drawing which shows the manufacturing method of the solar cell unit of the 1st Example which concerns on this invention, and the manufacturing method of a solar cell module following it. The cross-sectional schematic diagram of the silicon crystal type solar cell unit and solar cell module of a prior art example. (B) is a solar cell unit, (c) is a solar cell module, and (a) is an exploded view of the solar cell unit.

The present invention will be described more specifically with reference to the accompanying drawings. In the drawings of the present invention, unless otherwise specified, the upper side is depicted as an incident surface for external light (mainly sunlight).
FIG. 1 shows a solar cell unit according to a first embodiment of the present invention, in which (b) is a longitudinal sectional view and (a) is an exploded view thereof. Here, the exploded view is divided for each member for the sake of understanding, and does not indicate that each can exist independently.

  The solar cell unit includes a plurality of solar cells 4 (4a, 4b) with conductive material 5 arranged side by side in a plane, a connecting member 6 that electrically connects these solar cells, and solar cells. 4 (4a, 4b) comprising a filler layer 3 that protects the light-receiving surface side (upper side), and a light-transmitting surface member 2 made of glass laminated on the filler layer 3, and a solar cell On the light receiving surface of the cell 4 (that is, between the light receiving surface of the solar battery cell 4 and the filler layer 3), a film-like light transmissive resin layer 10 provided with an embossed pattern is formed.

  The filler layer 3 is formed so as to protect only the light receiving surface side of the solar battery cell 4 as shown in FIG. 1B, and the film cell back support layer is provided on the back surface side of the solar battery cell 4. 11 is formed, and a low hygroscopic foam layer (resin foam) 13 is formed on the lower side so as to sandwich a reflective film 12 such as a metal thin film. In addition, you may form the filler layer 3 so that the whole photovoltaic cell 4 may be protected.

  What should be noted here is that the film-like light-transmitting resin layer 10 is provided so as to be in contact with the light-receiving surface of the solar battery cell 4 (4a, 4b), and the filler layer 3 has a film-like light-transmitting property. It is located in the place far from the photovoltaic cell 4 rather than the conductive resin layer 10. When the film-like light-transmitting resin layer 10 is provided so as to be in contact with the light receiving surface of the solar battery cell 4, the photovoltaic power generation efficiency is improved as compared with the case where it is not provided or the case where it is provided above the solar battery cell 4 To do. This is true even if an embossed pattern is not applied to the film-like light transmissive resin layer 10 (see FIG. 2). Although details of the reason are not known, it is estimated that incident light is efficiently introduced into the solar battery cell 4 due to refraction of light in the film-like light-transmitting resin layer 10.

  The positional relationship is particularly effective when the light refractive index in the film-like light transmissive resin layer 10 is larger than the light refractive index in the filler layer 3. This is because light is efficiently introduced into the solar battery cell 4.

  FIG. 2 is a solar cell unit (exploded view) of a second embodiment according to the present invention. Except for forming a film-like light-transmitting resin layer 10 not provided with an embossed pattern on the light-receiving surface of the solar battery cell 4, it is the same as FIG. As described above, incident light will be efficiently introduced into the solar battery cell 4 by refraction of light in the film-like light-transmitting resin layer 10.

FIG. 3 shows a solar cell unit according to a third embodiment of the present invention, in which (b) is a longitudinal sectional view and (a) is an exploded view thereof.
The solar cell unit includes a plurality of solar cells 4 (4a, 4b) with conducting material 5 arranged in a plane and in a plane, a connection member 6 that electrically connects the solar cells 4 to each other, It is provided with a filler layer 3 that protects the light receiving surface side (upper side) of the battery cell 4 (4a, 4b) and a light transmissive surface member 2 laminated on the filler layer 3, and is light transmissive. Between the surface member 2 and the filler layer 3, a film-like light transmissive resin layer 10 provided with an embossed pattern is formed.

  Here, the filler layer 3 may be provided so as to protect the entire solar battery cell 4, but as shown in FIG. 3, only the light receiving surface side is protected, and the back surface side is the first implementation. A foam layer 13 is provided as in the example.

  In the third embodiment, the filler layer 3 is positioned closer to the solar battery cell 4 than the film-like light transmissive resin layer 10. In the case of such a positional relationship, the light refractive index in the filler layer 3 is preferably larger than the light refractive index in the film-like light transmissive resin layer 10. This is for efficiently introducing sunlight into the solar battery cell 4.

Next, the manufacturing method of the solar cell unit of the first embodiment according to the present invention and the subsequent manufacturing method of the solar cell module will be described with reference to FIG.
Conductive material 5 is arranged on the surface of two solar cells 4, and the two solar cells 4 are electrically connected to each other via conductive material 5 and connecting member 6. A large number of wirings 14 run on the surface of the solar battery cell 4, and the conductive material 5 is disposed on the wirings 14 (FIG. 4 (a2)).

  The transparent resin film 10 is laminated on the upper surface portion of the solar battery cell 4 where the conductive material 5 is not present, and the cell back support film 11 is laminated on the rear face side of the solar battery cell 4 (FIG. 4 (b1 / b2)). .

  A filler layer 3a is formed on the light-transmitting resin film 10 on the light-receiving surface side of the solar battery cell 4 (FIG. 4C). Note that, as described above, the filler layer 3 is prepared by preparing the same fillers (surface filler 3a and back filler 3b) on both sides for the solar battery cell 4, and finally one filler layer. 3 may be provided to protect the entire cell.

  By adopting such a method, the filler layer 3a can be thinned like an organic film material, and light absorption by the filler layer 3a can be reduced, so that the light incident efficiency is also improved. In addition, even if the thickness cannot be made uniform only by reducing the thickness of the filler layer 3a, the foam layer 13 is used to absorb irregularities under the cell back support film 11 (instead of the filler layer 3b). Thus, both thinning and surface flattening can be achieved (FIG. 4D).

  As described above, the light-transmitting surface member 2 and the antireflection film 1 prepared in advance are formed on the upper side of the filler layer 3a, and then accommodated in the molded resin frame 15, and the gap is sealed with the sealing resin. The solar cell unit is completed by sealing with 16 (FIG. 4E).

According to the method shown here, it becomes possible to produce many of the members of the solar cell unit with an organic compound except for some inorganic materials (solar cells and connection members), The range of material design can be expanded and the cost can be reduced.
Moreover, it becomes possible to manufacture each of the molded resin frames 15 by sequentially stacking the respective materials from the lower side and finally performing heat treatment or light irradiation collectively, which can greatly improve productivity. It becomes possible.

<Example of solar cell module production>
(I) The photosensitive resin composition solution was applied to a PET film (base material) to a thickness of 10 μm, the solvent was dried in an oven, a protective film (PP) was laminated, and UV curing was performed. A mold film was obtained. After punching the UV curable film by punching according to the electrodes on the light receiving surface and the back surface of a polycrystalline silicon solar cell with a thickness of 150 mm (mm) x 150 (mm) and a thickness of 0.3 mm, While the protective film (PP) was peeled off and aligned, this was placed on the surface of the cell so that the photosensitive resin layer was in contact with the cell, and a release film was placed thereon, followed by lamination using a vacuum laminator. After that, the PET film was peeled off, a transparent embossed film with unevenness was placed thereon, and the embossed structure was transferred again using a vacuum laminator. Further, this UV curable film was cured using an exposure apparatus.
While peeling and aligning the PP protective film of the UV curable film that has been punched, place it on the back of the cell so that the photosensitive resin layer is in contact with the cell, and then place a release film on it, using a vacuum laminator Laminated. This UV curable film was cured using an exposure apparatus, the PET film was peeled off, and a cell with a support film having an embossed pattern on the surface was produced.

(Ii) A solution in which conductive particles are dispersed in a thermosetting resin composition is applied to a PET film (base material) to a thickness of 10 μm, the solvent is dried in a furnace, and a PP protective film is applied. Laminated to make an anisotropic conductive film. Next, the cell with the support film (i) and the solder-plated copper ribbon were thermocompression bonded through an anisotropic conductive film, and the cells were connected in series.

(Iii) An unsaturated polyester resin composition was coated on a PP film, and glass fibers were dispersed on the PP film to form a sandwich structure with a similar coated film (referred to as SMC). . A basin-shaped molding frame having a cross-sectional structure as shown in FIG. A reflective film having a film thickness of 500 nm was formed on the PET substrate by vacuum deposition of aluminum. The reflective film was laminated to a polyethylene foam having a thickness of 3 mm via a urethane adhesive so that the Al surface was in contact with the adhesive layer (referred to as an Al laminate foam). An Al laminate foam was laminated on the molding frame via a urethane adhesive to obtain an FRP support.

(Iv) On the FRP support, the connected cells with a support film prepared in (ii) above were arranged, and a glass substrate was placed thereon via a highly transparent adhesive film. In this state, the glass substrate and the FRP support were clamped, and an epoxy resin sealant filled with silica was injected into the periphery. The epoxy resin was semi-cured and placed in a 150 ° C. oven for 20 minutes, and the clamp was removed. On top of that, fluorine-containing and siloxane-containing acrylic resin and its curing agent are diluted in butyl acetate (solvent), spray-coated so as to have a film thickness of about 80 nm after curing, and again placed in a furnace at 150 ° C. for 60 minutes, The antireflection film and the surrounding filler layer were cured to complete the solar cell module.

  In addition, when the module produced here is compared with the commercial module using the cell used here, the initial characteristics are the same, and the module produced here has a member cost and a manufacturing cost. It was estimated that about 40% could be reduced. In addition, in the reliability test, when the sunshine weather meter (Due cycle) test was performed for 1000 hours, the reduction in conversion efficiency of the commercial product was -10%, whereas the result was very good at -2%. It was. The weight reduction was about 2% in this prototype, but this greatly depends on the area of the module.

According to this invention, the following solar cell unit, the connection method of a photovoltaic cell, the connection structure of a photovoltaic cell, and the electrically conductive material for photovoltaic cell connection are provided.
(1) A solar cell unit comprising a plurality of solar cells, a connection member and a conductive material that electrically connect the solar cells, and a filler layer that protects at least the light receiving surface side of the solar cells. The conductive material is a solar cell unit that is a film adhesive having anisotropic conductivity including a polymer resin and conductive particles.
(2) The solar cell unit according to (1), wherein the polymer resin includes an acrylic polymer and a thermosetting resin.
(3) The sun according to (1) or (2), wherein 10 to 1,000,000 conductive particles are dispersed per 1 cm ² (area in plan view) of connection terminals in the film adhesive. Battery unit.
(4) The solar cell unit according to any one of (1) to (3), wherein the conductive material is thermocompression bonded at a temperature of 150 ° C. or lower.
(5) A solar cell connection method for electrically connecting a plurality of solar cells via a plurality of conductive materials and a connection member for electrically connecting the conductive materials to each other, wherein the conductive material is A method for connecting solar cells, which is a film-like adhesive that is disposed on the surface of each of the solar cells and has an anisotropic conductivity including a polymer resin and conductive particles.
(6) The solar cell connection method according to (5), wherein a plurality of wirings are arranged on a surface of the solar battery cell, and the conductive material is arranged so as to straddle the plurality of the wirings.
(7) The solar cell connection method according to (5) or (6), wherein the polymer resin contains an acrylic polymer and a thermosetting resin.
(8) Any one of (5) to (7), wherein 10 to 1,000,000 conductive particles are dispersed per 1 cm ² (area in plan view) of connection terminals in the film adhesive. The connection method of the photovoltaic cell as described in one.
(9) The method for connecting solar cells according to any one of (5) to (8), wherein the conductive material is thermocompression bonded at a temperature of 150 ° C. or lower.
(10) A solar cell connection structure in which a plurality of solar cells are electrically connected via a plurality of conductive materials and a connection member that electrically connects the conductive materials to each other. Is a solar cell connection structure which is a film-like adhesive which is disposed on the surface of the solar cell and which has a polymer resin and conductive particles and has anisotropic conductivity.
(11) The connection structure of solar cells according to (10), wherein a plurality of wirings are arranged on a surface of the solar cells, and the conductive material is arranged so as to straddle the plurality of the wirings.
(12) The solar cell connection structure according to (10) or (11), wherein the polymer resin includes an acrylic polymer and a thermosetting resin.
(13) Any one of (10) to (12), in which 10 to 1,000,000 conductive particles are dispersed per 1 cm ² (area in plan view) of the connection terminal in the film adhesive. The connection structure of the photovoltaic cell described in 1.
(14) The connection structure for solar cells according to any one of (10) to (13), wherein the conductive material is thermocompression bonded at a temperature of 150 ° C. or lower.
(15) A solar cell connecting conductive material that is electrically connected to each other by a connecting member and that electrically connects a plurality of solar cells, wherein the conductive material includes a polymer resin and conductive particles. A conductive material for connecting solar cells, which is a film adhesive having anisotropic conductivity.
(16) The conductive material for connecting solar battery cells according to (15), wherein the conductive material is disposed on a surface of each of the solar battery cells.
(17) The conductive material for connecting solar battery cells according to (15) or (16), wherein the polymer resin contains an acrylic polymer and a thermosetting resin.
(18) Any one of (15) to (17), wherein 10 to 1,000,000 conductive particles are dispersed per 1 cm ² (area in plan view) of connection terminals in the film adhesive. Conductive material for solar cell connection as described in one.
(19) The conductive material for solar cell connection according to any one of (15) to (18), wherein the conductive material is thermocompression bonded at a temperature of 150 ° C. or lower.

1: Antireflection film 2: Light transmissive surface member (tempered glass plate or transparent resin plate)
3: Filler layer 3a: Light-receiving-surface-side filler layer 3b: Back-side filler-material layer 4, 4a, 4b: Solar cell 5: Conductive material 4 + 5: Conductive material-equipped solar cell 6: Connection member 7: Back surface Protective material 8: Back support plate 9: Aluminum frame 9a: Reinforced aluminum frame 10: Film-like light transmissive resin layer (light transmissive resin film)
11: Film-like cell back support layer 12: Reflective film 13: Foam layer (low hygroscopic foam layer)
14: Wiring 15: Frame (molded resin frame)
16: Sealing resin

Claims (1)

A solar cell unit comprising a plurality of crystalline solar cells, a connecting member and a conductive material that electrically connect the solar cells, and a filler layer that protects at least the light receiving surface side of the solar cells. And
The conducting material is a film adhesive having anisotropic conductivity including a polymer resin and conductive particles,
The solar cell unit in which the light-receiving surface of one said photovoltaic cell and the surface on the opposite side to the light-receiving surface of another said photovoltaic cell are electrically connected through the said connection member and the said electrically-conductive material.

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