JP2005019975A - Filler layer for solar cell modules and solar cell module using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive filler layer for solar cell modules which is superior in adhesion of a transparent front substrate to a back protection sheet in the production of a solar cell module without deteriorating working environment and without exerting a bad effect on solar cell elements and electrodes etc. <P>SOLUTION: The filler layer for solar cell modules in which, in order to attain the purpose above, a filler layer for solar cell modules containing silane-modified resin obtained by polymerizing an ethylenically unsaturated silane compound with polyethylene for polymerization is provided, is characterised in that, when this layer is applied to a solar cell module, the gel fraction of the layer is kept 30 % or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a solar cell module filler layer having a silane-modified resin, and a solar cell module using the same.

In recent years, solar cells as clean energy sources have attracted attention due to increasing awareness of environmental problems, and solar cell modules having various forms have been developed and proposed.
In general, the above solar cell module is laminated in the order of, for example, a transparent front substrate, a filler layer, a solar cell element as a photovoltaic element, a filler layer, a back surface protection sheet, and the like, and then vacuum suction them. Then, it is manufactured using a lamination method or the like that is thermocompression bonded.

Currently, ethylene-vinyl acetate copolymer resin having a thickness of 100 μm to 1500 μm is the most common material constituting the filler layer for solar cell modules from the viewpoint of processability, workability, manufacturing cost, etc. It is used as a typical one.
However, the filler layer made of an ethylene-vinyl acetate copolymer resin does not necessarily have sufficient adhesive strength with the transparent front substrate or the back surface protective sheet, and there is a problem that its weakness is exposed to long-term use outdoors. is there. Furthermore, when producing a solar cell module using a filler layer made of an ethylene-vinyl acetate copolymer resin, the ethylene-vinyl acetate copolymer resin causes thermal decomposition or the like due to conditions such as thermocompression bonding, Acetic acid gas and the like are generated, which not only deteriorates the working environment, but also adversely affects the solar cell elements, electrodes, and the like, thereby causing deterioration and a decrease in power generation efficiency.

Therefore, a method of polymerizing a silane compound to a resin has been performed as a method of imparting adhesiveness to a resin, which is a material of the filler layer, to glass or metal used for a transparent front substrate or a back protective sheet.
In general, there are two polymerization methods: copolymerization and graft polymerization. Copolymerization is a method in which a monomer, a catalyst, and an unsaturated silane compound are mixed and a polymerization reaction is performed at a predetermined temperature and pressure. Graft polymerization is a method in which a polymer, a free radical generator, and an unsaturated silane compound are mixed, This is a method in which a silane compound is polymerized in a polymer main chain or side chain by stirring at a temperature.

For example, a silane coupling agent is added to an ethylene-vinyl acetate copolymer resin in order to cause a crosslinking reaction to occur in the resin that is the material of the filler layer during thermocompression bonding and to impart strength, heat resistance, durability, and the like of the material itself. And a method using a resin sheet added with an organic peroxide (Patent Document 1), a method using a resin sheet obtained by adding an organic peroxide to an ethylene-vinyl acetate copolymer resin graft-modified with an organic silane compound (Patent Document 1) 2) and a method using a resin sheet obtained by adding an organic peroxide to an ethylene-ethylenically unsaturated carboxylic acid ester-ethylenically unsaturated silane compound terpolymer resin (Patent Document 3) has been proposed. However, since both contain an organic peroxide, the organic peroxide decomposes during the molding of the sheet to cause a cross-linking reaction of the resin. The molding process is difficult, the processability at the time of lamination is reduced, or the decomposition product derived from the organic peroxide remains at the adhesion interface at the time of lamination, causing the adhesion inhibition. .
Further, there is a problem that the silane compound is expensive, and further improvement is still required.

Japanese Examined Patent Publication No. 62-14111 Japanese Examined Patent Publication No. 62-9232 Japanese Examined Patent Publication No. 6-104729

  Therefore, the present invention provides an inexpensive solar cell that is excellent in adhesion to the transparent front substrate and the back surface protection sheet, does not deteriorate the working environment, and does not adversely affect the solar cell elements and electrodes during the production of the solar cell module. The main object is to provide a filler layer for battery modules.

  In order to achieve the above object, the present invention provides a solar cell module filler layer having a silane-modified resin obtained by polymerizing an ethylenically unsaturated silane compound and a polymerization polyethylene, the solar cell module When a filler layer is used for a solar cell module, a gel layer has a gel fraction of 30% or less, and a solar cell module filler layer is provided.

  Since the filler layer for a solar cell module as described above has a silane-modified resin, it has excellent adhesion to a transparent front substrate for a solar cell module and a back surface protective sheet such as glass, and the main chain is polyethylene. Therefore, there is an advantage that no harmful gas is generated and the working environment is not deteriorated. In addition, when used in a solar cell module, the gel fraction of the solar cell module filler layer is in the above range, so that it can be sealed in a short time, and further there is an advantage that heat treatment or the like is unnecessary. . Furthermore, since the gel fraction is low in this way, it is possible to easily soften and melt the filler layer by heating, and thereby, for example, solar cell elements used in solar cell modules and transparent The front substrate or the like can be reused.

In this invention, it is preferable that the said filler layer for solar cell modules further has polyethylene for addition. Since the cost of the silane-modified resin is high, it is preferable that the filler layer for the solar cell module contains the additive polyethylene.
In the present invention, the polyethylene for polymerization and the polyethylene for addition further comprise low density polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, very low density polyethylene, and linear low density polyethylene. It is preferably at least one polyethylene selected from the group.

  Furthermore, it is preferable that the quantity of the said silane modified resin contained in the said filler layer for solar cell modules is 1 to 80 weight%. The silane-modified resin has an ethylenically unsaturated silane compound that is polymerized with polyethylene for polymerization, thereby providing adhesion to glass or the like. Therefore, the said solar cell module filler layer has adhesiveness with the transparent front substrate for solar cell modules, a back surface protection sheet, and a solar cell element by having the above silane modified resins. Therefore, if it is less than the above range, the adhesion to glass or the like is insufficient, and if it exceeds the above range, the adhesion to glass or the like is considered to be unchanged and the cost is increased.

  Furthermore, it is preferable that 8 ppm to 3500 ppm of Si (silicon) is contained in the filler layer for solar cell module as the amount of polymerized Si. This is because, for the same reason as described above, by having the polymerized Si amount within this range, it is possible to improve the adhesion to the solar cell element and the transparent front substrate.

  Furthermore, in this invention, it is preferable that the silanol condensation catalyst is not substantially contained in the said filler layer for solar cell modules. In the present invention, the gel fraction in the filler layer is characterized by being a predetermined value or less, and is generally used for water crosslinking in a resin composition using an ethylenically unsaturated silane compound. This is because the desired gel fraction cannot be obtained if the silanol condensation catalyst blended in is contained.

  The present invention also provides a solar cell module comprising the solar cell module filler layer. The solar cell module having the solar cell module filler layer according to the present invention has the advantages of the solar cell module filler layer as described above and is advantageous in terms of cost.

  The filler layer for a solar cell module of the present invention has the advantage that it has excellent adhesiveness with the glass used for the protective sheet for the solar cell module and does not deteriorate the working environment. This makes it possible to perform sealing, and heat treatment or the like is unnecessary. Furthermore, it has the effect that the reuse of the member contained in a solar cell module is enabled.

  The present invention includes a solar cell module filler layer and a solar cell module using the same. Hereinafter, the filler layer for solar cell modules and the solar cell module using the same will be described. In the present invention, a sheet means any of a sheet-like material or a film-like material, and a film means any case of a film-like material or a sheet-like material. is there.

A. First, the filler layer for solar cell modules of the present invention will be described. The filler layer for a solar cell module according to the present invention is a filler layer for a solar cell module having a silane-modified resin obtained by polymerizing an ethylenically unsaturated silane compound and a polyethylene for polymerization, the filler for the solar cell module When the material layer is used for a solar cell module, the gel fraction is not more than a predetermined value.
Hereinafter, each structure of such a filler layer for solar cell modules is demonstrated.

1. Silane Modified Resin The silane modified resin used in the present invention is obtained by polymerizing an ethylenically unsaturated silane compound and polymerization polyethylene. Such a silane-modified resin is obtained by mixing an ethylenically unsaturated silane compound, a polymerization polyethylene and a radical generator, melting and stirring at a high temperature, and graft-polymerizing the ethylenically unsaturated silane compound onto the polymerization polyethylene. be able to.

  The polymerization polyethylene used in the present invention is not particularly limited as long as it is a polyethylene-based polymer. Specifically, the low-density polyethylene, the medium-density polyethylene, the high-density polyethylene, the ultra-low density polyethylene, and the ultra-low density. High density polyethylene or linear low density polyethylene is preferred. Moreover, these can also use 1 type, or 2 or more types.

Furthermore, as the polyethylene for polymerization, polyethylene having many side chains is preferable. Here, usually, polyethylene with many side chains has a low density, and polyethylene with few side chains has a high density. Therefore, it can be said that polyethylene with a low density is preferable. The density of the polyethylene for polymerization in the present invention is preferably in the range of 0.850 to 0.960 g / cm ³ , more preferably in the range of 0.865 to 0.930 g / cm ³ . This is because if the polymerization polyethylene is a polyethylene having many side chains, that is, a polyethylene having a low density, the ethylenically unsaturated silane compound is easily graft-polymerized to the polymerization polyethylene.

  On the other hand, the ethylenically unsaturated silane compound used in the present invention is not particularly limited as long as it is graft-polymerized with the above-described polyethylene for polymerization. For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyl Triisopropoxysilane, vinyltributoxysilane, vinyltripentyloxysilane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltrimethylenedioxysilane, vinyltriethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane , And at least one selected from the group consisting of vinyltricarboxysilane can be used. In the present invention, among these, vinyltrimethoxysilane is preferably used.

  In the present invention, the amount of the ethylenically unsaturated silane compound contained in the solar cell module filler layer is preferably 10 ppm or more, more preferably 20 ppm or more. The solar cell module filler layer has the ethylenically unsaturated silane compound polymerized with the polymerizing polyethylene, so that the material used for the transparent front substrate and back sheet for solar cell modules described later, such as glass, etc. The adhesion is realized. Therefore, when it is less than the range mentioned above, adhesiveness with glass etc. is insufficient. Further, the upper limit of the amount of the ethylenically unsaturated silane compound is preferably 4000 ppm or less, and more preferably 3000 ppm or less. The upper limit is not limited in terms of adhesion to glass or the like, but if it exceeds the above range, the adhesion to glass or the like does not change and the cost increases.

  The silane-modified resin is preferably contained in the solar cell module filler layer in the range of 1 to 80% by weight, more preferably in the range of 5 to 70% by weight. Similarly, in this case, the silane-modified resin has an ethylenically unsaturated silane compound polymerized with the polymerization polyethylene, thereby providing adhesion to glass or the like. Therefore, the said filler layer for solar cell modules has high adhesiveness with glass etc. by having the above silane modified resins. Therefore, the above-mentioned range is preferably used from the viewpoint of adhesion to glass or the like and cost.

Further, the silane modified resin preferably has a melt mass flow rate at 190 ° C. of 0.5 to 10 g / 10 minutes, more preferably 1 to 8 g / 10 minutes. It is because it is excellent in the moldability of the filler layer for solar cell modules, adhesiveness with the transparent front substrate and the back surface protective sheet, and the like.
Moreover, it is preferable that melting | fusing point of the said silane modified resin is 110 degrees C or less. When manufacturing a solar cell module using the solar cell module filler layer, the above range is preferable in terms of workability and the like.

  Examples of the radical generator to be added to the silane-modified resin include hydroperoxides such as diisopropylbenzene hydroperoxide and 2,5-dimethyl-2,5-di (hydroperoxy) hexane; di-t-butyl Peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-peroxy) ) Dialkyl peroxides such as hexyne-3; bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, etc. Diacyl peroxides; t-butyl peroxyacetate Over DOO, t- butyl peroxy-2-ethylhexanoate, t- butyl peroxypivalate, t- butyl peroxy octoate. t-butylperoxyisopropyl carbonate, t-butylperoxybenzoate, di-t-butylperoxyphthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2, Peroxyesters such as 5-di (benzoylperoxy) hexyne-3; organic peroxides such as methyl peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; or azobisisobutyronitrile and azobis (2 , 4-dimethylvaleronitrile) and the like.

The amount of the radical generator used is preferably 0.001% by weight or more in the silane-modified resin. This is because radical polymerization between the ethylenically unsaturated silane compound and the polymerization polyethylene hardly occurs when the amount is less than the above range.
In addition, the silane modified resin used for this invention can be used also for a laminated glass use. Laminated glass is produced by thermocompression bonding between a glass and a glass with a flexible and tough resin or the like. From the viewpoint of adhesion to glass, the silane-modified resin may be used. it can.

2. Additive Polyethylene In the present invention, the solar cell module filler layer preferably includes the silane-modified resin and the additive polyethylene. Examples of the polyethylene for addition include the same as those described in the above-mentioned “1. Silane modified resin”. In the present invention, the additive polyethylene is particularly preferably the same resin as the polymerization polyethylene. Since the cost of the silane-modified resin is high, the silane-modified resin and the additive polyethylene are mixed to form the solar cell module filler layer, rather than forming the solar cell module filler layer only with the silane-modified resin. This is because it is advantageous in terms of cost.
The content of polyethylene for addition is preferably 0.01 to 9900 parts by weight, and more preferably 90 to 9,900 parts by weight with respect to 100 parts by weight of the silane modified resin.
When using 2 or more types of the said silane modified resin, it is preferable that content of the polyethylene for addition becomes the said range with respect to the total amount of 100 weight part.

The polyethylene for addition preferably has a melt mass flow rate at 190 ° C. of 0.5 to 10 g / 10 min, more preferably 1 to 8 g / 10 min. It is because it is excellent in the moldability of the filler layer for solar cell modules.
Furthermore, the melting point of the additive polyethylene is preferably 130 ° C. or lower. The above range is preferable in terms of workability and the like during the production of the solar cell module using the solar cell module filler layer.
The melting point is measured by differential scanning calorimetry (DSC) in accordance with the plastic transition temperature measurement method (JISK7121). In this case, when two or more melting points exist, the higher temperature is defined as the melting point.

3. Additives In the present invention, additives such as a light stabilizer, an ultraviolet absorber, and a heat stabilizer can be used as necessary. The solar cell module filler layer of the present invention has a silane-modified resin as described above, and a mechanical stabilizer and an adhesive strength that are stable over a long period of time by adding a light stabilizer, an ultraviolet absorber, and a thermal stabilizer to this. , Yellowing prevention, crack prevention, and excellent processability can be obtained.
The light stabilizer captures the active species at the start of photodegradation in the polymer used in the polymerization polyethylene and the additive polyethylene and prevents photooxidation. Specifically, at least one selected from the group consisting of a hindered amine compound, a hindered piperidine compound, and the like can be used.

  The ultraviolet absorber absorbs harmful ultraviolet rays in sunlight, converts them into innocuous heat energy in the molecule, and initiates photodegradation activity in the polymer used for the polymerization polyethylene and the additive polyethylene. It prevents the species from being excited. Specifically, benzophenone-based, benzotriazole-based, salicylate-based, acrylonitrile-based, metal complex-based, hindered amine-based, ultrafine titanium oxide (particle diameter: 0.01 μm to 0.06 μm) or ultrafine zinc oxide ( At least one type selected from the group consisting of inorganic ultraviolet absorbers (particle diameter: 0.01 μm to 0.04 μm) can be used.

  Examples of the heat stabilizer include tris (2,4-di-tert-butylphenyl) phosphite, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphorus Acid, tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4'-diylbisphosphonite, and bis (2,4-di-tert-butylphenyl) penta Phosphorus heat stabilizers such as erythritol diphosphite; and lactone heat stabilizers such as a reaction product of 8-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene Can do. Moreover, these can also use 1 type (s) or 2 or more types. Among these, it is preferable to use a phosphorus heat stabilizer and a lactone heat stabilizer in combination.

The content of the light stabilizer, ultraviolet absorber, heat stabilizer and the like varies depending on the particle shape, density, etc., but is preferably in the range of 0.01 to 5% by weight in the solar cell module filler layer. .
The solar cell module filler layer has a low gel fraction when used in a solar cell module as will be described later, and therefore, the silane-modified resin forms a crosslinked structure. There is no need to do. Therefore, a crosslinking agent or a catalyst for promoting the condensation reaction of silanol groups is not particularly required.

  Specifically, it is preferable that a silanol condensation catalyst that accelerates a dehydration condensation reaction between silanols of silicone such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctate, and dioctyltin dilaurate is substantially not contained. Here, “substantially not contained” refers to a case where the amount is 0.05 parts by weight or less with respect to 100 parts by weight of the resin constituting the filler layer for solar cell module.

4). Solar Cell Module Filler Layer The film thickness of the solar cell module filler layer of the present invention is preferably in the range of 10 to 2000 μm, particularly preferably in the range of 100 to 1250 μm. If it is thinner than the above range, the cell cannot be supported, and the cell is likely to be damaged.If it is thicker than the above range, the module weight becomes heavy and not only the workability during installation is bad, but also in terms of cost. It may be disadvantageous.

Furthermore, in the present invention, Si (silicon) is contained in the solar cell module filler layer in the range of 8 ppm to 3500 ppm, particularly 10 ppm to 3000 ppm, especially 50 ppm to 2000 ppm as the amount of polymerized Si. It is preferable. This is because when the amount of polymerized Si is included within this range, it is possible to maintain good adhesion with the transparent front substrate and the solar cell element, and it can be said that the above range is preferable from the viewpoint of cost.
In the present invention, as a method for measuring the amount of polymerized Si, only the filler layer is heated, burned, and ashed to convert polymerized Si to SiO _2. A method of quantifying the amount of polymerized Si by ICP emission analysis (high-frequency plasma emission analyzer: ICPS8100 manufactured by Shimadzu Corporation) is used after dissolution.

Furthermore, the resin constituting the solar cell module filler layer preferably has a melt mass flow rate at 190 ° C. of 0.5 to 10 g / 10 min, more preferably 1 to 8 g / 10 min. . It is because it is excellent in the moldability of the filler layer for solar cell modules, adhesiveness with the transparent front substrate and the back surface protective sheet, and the like.
Moreover, it is preferable that melting | fusing point of resin which comprises the said filler layer for solar cell modules is 130 degrees C or less. When manufacturing a solar cell module using the solar cell module filler layer, the above range is preferable in terms of workability and the like. Further, when reusing components constituting the solar cell module, such as solar cell elements or transparent front substrates, if the melting point is about this level, they can be easily reused. In addition, since the measuring method of melting | fusing point is the same as that of what was mentioned above, description here is abbreviate | omitted.

  Moreover, when the filler layer for solar cell modules of this invention is used for a solar cell module, it is preferable that a gel fraction is 30% or less, especially 10% or less, especially 0%. Since the silane-modified resin used in the present invention does not form a crosslinked structure in this way, it can be sealed in a short time, and post-treatment such as heat treatment is unnecessary. Moreover, when a gel fraction exceeds the said range, the workability at the time of solar cell module manufacture will fall, and the improvement of adhesiveness with a transparent front substrate and a back surface protection sheet will not be recognized. Furthermore, it is because it will become difficult to reproduce | regenerate the members contained in a solar cell module, for example, a solar cell element, and a transparent front substrate, when a gel fraction exceeds the said range.

The gel fraction when the solar cell module filler layer is used for the solar cell module is, for example, a transparent front substrate, a solar cell module filler layer, a solar cell element, a solar cell module filler layer, And a back surface protective sheet are sequentially laminated, and then the solar cell module is manufactured using each layer as an integrally molded body by using a normal molding method such as a lamination method in which these are integrated and then vacuum sucked and thermocompression bonded. It refers to the gel fraction of the solar cell module filler layer.
As a method for measuring the gel fraction, 1 g of the solar cell module filler layer is weighed and placed in an 80 mesh wire mesh bag. A sample with the wire mesh is put into a Soxhlet extractor, and xylene is refluxed at the boiling point. After 10 hours of continuous extraction, the whole wire mesh and the sample are taken out, weighed after the drying treatment, the weight before and after extraction is compared, the weight% of the remaining insoluble matter is measured, and this is used as the gel fraction.

5. Next, the manufacturing method of the filler layer for solar cell modules of this invention is demonstrated.
First, the preparation method of the silane modified resin used for this invention is demonstrated. The silane-modified resin can be obtained by heat-melt mixing a mixture of an ethylenically unsaturated silane compound, a polymerization polyethylene and a radical generator, and graft-polymerizing the ethylenically unsaturated silane compound onto the polymerization polyethylene. .

Although there is no particular limitation on the method of heating and melting and mixing these mixtures, the additive is preferably a method in which a master batch in which the additives are previously kneaded and contained in the resin is mixed with the main raw material and extruded and melted. The heating temperature is preferably 300 ° C. or lower, and more preferably 270 ° C. or lower. The silane-modified resin is preferably melt-mixed in the above range because the silanol group portion is easily cross-linked and gelled by heating.
Next, the formation method of the filler layer for solar cell modules of this invention is demonstrated. After the silane-modified resin is heated and melted and mixed as described above, the obtained silane-modified resin can be pelletized, and heated and melted again to be extruded, but the silane-modified resin and the silane-modified resin are placed in the hopper of the extruder. It is also possible to mix and add the additive polyethylene and heat and melt it in a cylinder, and the latter is superior in terms of cost.

After the above-described resin is heated and melted, it can be formed into a sheet having a thickness of 100 to 1500 μm by an existing method such as T-die or inflation, and used as a filler layer for a solar cell module.
The heating temperature at the time of heating and melting again is preferably 300 ° C. or lower, more preferably 270 ° C. or lower. As described above, since the silanol group portion of the silane-modified resin is easily cross-linked and gelled by heating, it is desirable to heat and melt the resin within the above range and to extrude.

B. Next, the solar cell module of the present invention will be described. The solar cell module of the present invention has the filler layer for a solar cell module of the present invention described above. FIG. 1 is a schematic cross-sectional view showing an example of a solar cell module manufactured using a filler layer for a solar cell module. As shown in FIG. 1, a transparent front substrate 1, a solar cell module filler layer 2, a solar cell element 3 as a photovoltaic element, a solar cell module filler layer 2, a back surface protection sheet 4, etc. Then, the solar cell module T can be manufactured using each layer as an integrally formed body by using a normal forming method such as a lamination method in which these are integrated and then vacuum sucked and thermocompression bonded.

  In the present invention, the lamination temperature when such a lamination method is used is preferably in the range of 90 ° C to 230 ° C, and more preferably in the range of 110 ° C to 190 ° C. If the temperature is lower than the above range, it may not melt sufficiently and the adhesion to the transparent front substrate, auxiliary electrode, solar cell element, back surface protective sheet, etc. may be deteriorated. This is not preferable because water cross-linking due to is likely to proceed and the gel fraction may increase. The laminating time is preferably within a range of 5 to 60 minutes, and particularly preferably within a range of 8 to 40 minutes. If the time is shorter than the above range, it may not be sufficiently melted and the adhesion with the same member may be deteriorated, and if it is long, there may be a problem in the process, especially depending on the temperature and humidity conditions, the gel fraction This is because it becomes an increase factor. As for humidity, if it is too high, it will lead to an increase in the gel fraction, and if it is too low, there is a possibility that the adhesion to various members will be reduced. .

In the present invention, the solar cell module filler layer may be provided between the transparent front substrate and the solar cell element, or between the transparent front substrate and the solar cell element, and the back surface protective sheet and the solar cell. You may provide between elements.
Moreover, in the said solar cell module, it can laminate | stack by adding another layer arbitrarily for purposes, such as absorptivity of sunlight, reinforcement, others.

As the transparent front substrate used in the solar cell module of the present invention, glass, a fluorine resin sheet, a transparent composite sheet obtained by laminating and laminating a weather resistant film and a barrier film, and the like can be used.
Moreover, as a back surface protection sheet used for the solar cell module of the present invention, a metal such as aluminum, a fluorine resin sheet, a composite sheet obtained by laminating and laminating a weather resistant film and a barrier film, or the like can be used.

C. Reuse of solar cell module In the present invention, the gel fraction in the filler layer in the case of a solar cell module as described above is below a predetermined range, so that the solar cell module after use or during the manufacturing process It is possible to reuse a member of a solar cell module in which a defect occurs, specifically, a solar cell element or a transparent front substrate. Hereinafter, such reuse will be described separately for a method for producing a regenerated solar cell element, a method for producing a regenerated transparent front substrate, and a method for reusing a solar cell module.

(1) Manufacturing method of regenerative solar cell element First, the manufacturing method of a regenerative solar cell element is demonstrated. A method for manufacturing a regenerative solar cell element is a method for manufacturing a regenerative solar cell element that obtains a regenerative solar cell element from the solar cell module of the present invention described above, and the softening of a resin that is a constituent material of the filler layer of the solar cell module A heating step of heating to a temperature equal to or higher than a point, a separation step of separating and separating the solar cell element from the filler layer plasticized by heating, and a removal step of removing the filler layer attached to the solar cell element It is characterized by that. Hereinafter, each step will be described.

1. Heating Step In the heating step, the solar cell module is heated to a temperature equal to or higher than the softening point of the resin that is a constituent material of the filler layer. By heating to a temperature equal to or higher than the softening point of the resin constituting the filler layer in this way, the resin that is a constituent material of the filler layer is softened and melted, and the filler layer can be easily removed.

  The heating method is a method in which the solar cell module of the present invention is put into a container filled with a heated gas, a solid such as liquid or powder, or a combination thereof, or the solar cell module is held on a heated hot plate. The method etc. are mentioned.

  The heating temperature is a temperature equal to or higher than the softening point of the resin that is a constituent material of the filler layer, and is appropriately selected according to the resin used. Here, the softening point refers to the Vicat softening temperature measured based on the JIS standard K7206 of the thermoplastic resin. The heating temperature in the heating step is preferably the same temperature as the Vicat softening temperature, or preferably 0 ° C. to 250 ° C. or higher and higher than the Vicat temperature, more preferably 10 ° C. to 150 ° C. or more, and further preferably 20 ° C. to 20 ° C. It is preferably within a range of 130 ° C. or higher.

  The specific heating temperature in the heating step is preferably in the range of 20 ° C to 450 ° C, more preferably in the range of 30 ° C to 350 ° C, and still more preferably in the range of 110 ° C to 170 ° C.

2. Separation step The separation step in the present invention is a step of separating the solar cell element by utilizing the fact that the filler layer is softened and melted by heating in the heating step. The separation method may be performed by any method as long as it can be separated without damaging the solar cell element.
Examples of the separation method include a method using a separation means and a method of applying a shear stress.

The method using the separating means is a filler layer disposed between the front transparent substrate and the solar cell element of the solar cell module heated in the heating step described above, and disposed between the solar cell element and the back surface protective sheet. The filler layer is cut by passing the separating means, and the front transparent substrate and the back surface protective sheet are separated from the solar cell element. As such a separating means, a softened filler layer is used. Although it will not specifically limit if it is a means which can cut | disconnect, A wire etc. can be mentioned as a suitable example.
Moreover, as a method of applying the shearing force, the solar cell module heated in the heating step described above is extruded in the lateral direction with respect to at least one of the solar cell element or the transparent front substrate and at least one of the solar cell element or the back surface protective sheet. Thus, a shearing force is applied to the filler layer, thereby separating the front transparent substrate and the back surface protective sheet from the solar cell element.

3. Removal Step In the removal step in the present invention, the filler layer attached to the separated solar cell element is removed. Examples of the removal method include physical cleaning that physically removes the filler layer, chemical cleaning that chemically removes the filler layer, or a combination thereof.

  Examples of the physical cleaning include a method of spraying gas, liquid or solid, or a combination thereof, and a method of wiping with a cloth or the like. The physical cleaning is preferably performed while the filler layer is heated. For example, an air blast method or a shot blast method in which a shot of a steel ball is jetted at high speed using compressed air or centrifugal force in a heated atmosphere can be used. If the deposit is a part corresponding to the filler layer, physical cleaning is useful.

  In this physical cleaning, it is necessary to remove deposits so as not to damage the regenerative solar cell element. Therefore, for example, when the fine particle is sprayed to remove the filler layer, the particle size of the fine particle is preferably in the range of 5 μm to 500 μm. For example, solids that can be used for physical cleaning include steel abrasives, stainless steel abrasives, zinc abrasives, copper abrasives, alumina abrasives, silicon carbide abrasives, glass abrasives, resin abrasives, Examples thereof include silica sand, ceramic beads, zirconia, slag, calcium carbonate, and baking soda.

Examples of the liquid include a heated organic solvent and a metal liquid.
Examples of the gas include air, nitrogen gas, argon gas, and inert gas such as helium gas.
Specific examples include a method of removing the release layer from the surface of the solar cell element by immersing the separated solar cell element in an organic solvent such as xylene and refluxing xylene.

  Examples of chemical cleaning include a method of treating with an acid or an alkali, a method of dissolving with a solvent, and the like. The solvent that can be used for chemical cleaning can be appropriately selected depending on the adhering filler layer.

  As a method of combining physical cleaning and chemical cleaning, for example, a method in which the deposit is completely removed by an air blast method or a shot blast method after being immersed in a liquid that dissolves the deposit to some extent.

  As described above, deposits can be removed, and a regenerated solar cell element can be easily manufactured from a used solar cell module or the like by washing with alcohol or the like as necessary.

(2) Method for Producing Recycled Transparent Front Substrate Next, a method for producing a regenerated transparent front substrate will be described. A method for producing a regenerated transparent front substrate is a method for producing a regenerated transparent front substrate obtained from the above-described solar cell module of the present invention, wherein the solar cell module is a constituent material of a filler layer. Is heated to a temperature equal to or higher than the softening point of the resin, the separation step for separating the recycled transparent front substrate by peeling the filler layer plasticized by heating, and attached to the transparent front substrate And a removing step for removing the filler layer. Hereinafter, each step will be described.

1. Heating step In the heating step, the front transparent substrate can be easily peeled from the filler layer by heating the solar cell module to a temperature equal to or higher than the softening point of the resin that is a constituent material of the filler layer. It is. Since the heating method and the heating temperature are the same as those described in the column of “(1) Manufacturing method of regenerative solar cell element”, description thereof is omitted here.

2. Separation process In the separation process, the transparent front substrate is separated and separated from the filler layer softened and melted by heating in the heating process. The separation method is not particularly limited as long as it does not damage the transparent front substrate.
Specifically, a method using the separation means described in the above-mentioned section “B. Manufacturing method of regenerated solar cell element” and a method of applying shear stress can be mentioned.

3. Removal Step In the removal step, the filler layer attached to the transparent front substrate is removed. The removal method can be carried out by physical cleaning, chemical cleaning, or a combination thereof, as described in the section of “(1) Manufacturing method of regenerated solar cell element”. Since details are as described above, description thereof is omitted here.
After removing the filler layer, the recycled transparent front substrate can be easily produced from the used solar cell module by washing with alcohol or the like if necessary.

(3) Reuse method of solar cell module Finally, the reuse method of a solar cell module is demonstrated. The method for reusing a solar cell module is a method for reusing a solar cell module in which members are reused from the solar cell module described in the section “B. Solar cell module”. It has a heating step of heating to a temperature equal to or higher than the softening point of the resin as a material, and a separation step of separating and separating the member from the filler layer plasticized by heating.

According to such a method for reusing a solar cell module, for example, a member such as a solar cell element included in a solar cell module which is regarded as a defective product during processing of the solar cell module, a solar cell element of a solar cell module recovered after use, etc. These members can be reused (recycled or reused), which is not only advantageous in terms of cost but also suitable when considering the global environment.
As described above, the solar cell module used in the method for reusing the solar cell module includes a solar cell module that has been determined to be defective in the manufacturing process of the solar cell module and a solar cell module that has been recovered after use. be able to.

  In the present invention, such a solar cell module is subjected to a heating step and a separation step. The heating step and the separation step are performed according to the above-mentioned “(1) Method for producing a regenerative solar cell element” or “ Since it is the same as that described in “(2) Manufacturing method of recycled transparent front substrate”, the description is omitted here.

In such a method for reusing a solar cell module, it is preferable that a back surface protection sheet separation step is simultaneously performed in the separation step.
For example, when using a material that generates harmful gas by heating, such as a fluororesin, as the back surface protection sheet, the back surface protection sheet can be reused by separating the back surface protection sheet from the solar cell module in the back surface protection sheet separation step. This is because sometimes it is possible to prevent generation of harmful gas due to heating of the back surface protection sheet, thereby reducing the environmental load.
The separation of the back surface protection sheet may be performed simultaneously with the separation of the solar cell element or the transparent front substrate, or may be performed before the separation of these members.

  In the present invention, the process after the separation step differs depending on whether the member is used as it is (reuse) or the member is used as a material (recycle). In the case of reuse, for example, when the member is a solar cell element or a transparent front substrate, it is described in the above “(1) Method for producing regenerated solar cell element” or “(2) Method for producing regenerated transparent front substrate”. Reused using processing methods. On the other hand, when it is recycled, it is recycled according to the recycling method described later.

  Thus, whether to reuse or recycle is determined at the stage of the solar cell module, for example, it is clear that the solar cell element has already been damaged, and after the separation step, the solar cell It may be determined by looking at the state of members constituting the solar cell module such as an element and a transparent front substrate.

(Recycling Law)
In the method for reusing a solar cell module of the present invention, a method for recycling a solar cell element and a transparent front substrate among members of the solar cell module will be described.
1. In the case where the element is damaged after the separation step, the solar cell element is recycled without being subjected to the above-described removal step or after being used for a different use from the solar cell element.
Specifically, it is used for re-melting to re-form and recycle Si ingots, or for other uses when there are many impurities in Si.

2. Transparent Front Substrate Also in this case, after the separation step, the above-described removal step is performed or is performed, and then used as an application different from the transparent front substrate. Specifically, it is a method of recovering glass raw material (cullet) and melting it to re-form the plate glass.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

The following examples further illustrate the invention.
[Example 1]
(1) Preparation of silane modified resin Density 0.898 g / cm ³ , melt mass flow rate at 190 ° C. (referred to as MFR in the table) 2 g / 10 min linear low density polyethylene (referred to as LLDPE in the table) To 98 parts by weight, 2 parts by weight of vinyltrimethoxysilane and 0.1 part by weight of dicumyl peroxide as a radical generator were mixed, and heated and melted at 200 ° C. to obtain a silane-modified resin.

(2) Formation of solar cell module filler layer 5 parts by weight of the silane-modified resin, 95 parts by weight of linear low-density polyethylene having a density of 0.898 g / cm ³ , separately prepared light-proofing agent, UVA, and antioxidant 5 parts by weight of master batch (85 parts by weight of linear low density polyethylene, 2.5 parts by weight of hindered amine light stabilizer, 7.5 parts by weight of benzophenone UV absorber, 5 parts by weight of phosphorus heat stabilizer) Mixed, melted, processed, and pelletized), and put into a hopper of a φ25 mm extruder and a film molding machine having a 300-mm-wide T-die, an extrusion temperature of 230 ° C., a take-up speed of 3 m / min, and a thickness of 400 μm A sheet was formed. The above film formation could be carried out without hindrance. Through these series of operations, a filler layer for a solar cell module was obtained.

(3) Production of Solar Cell Module Using the above solar cell module filler layer, a 3 mm thick glass plate, a 400 μm thick solar cell module filler layer prepared in (2) above, and crystalline silicon Solar cell element, filler layer for solar cell module having a thickness of 400 μm, a polyvinyl fluoride resin sheet (PVF) having a thickness of 38 μm, an aluminum foil having a thickness of 30 μm, and a polyvinyl fluoride resin having a thickness of 38 μm A laminated sheet composed of a sheet (PVF) is laminated via an acrylic resin adhesive layer, the solar cell element surface is directed upward, and a vacuum laminator for producing a solar cell module at 150 ° C. for 15 minutes. The solar cell module was obtained by pressure bonding.

[Examples 2 to 11]
(1) Preparation of silane-modified resin A silane-modified resin was obtained in the same manner as in Example 1 except that the polymerization polyethylene, the ethylenic silane compound, the radical generator, and the mixing ratio thereof shown in Table 1 were used.

(2) Formation of solar cell module filler layer Under the conditions shown in Table 2, a solar cell module filler layer was obtained in the same manner as in Example 1. In the table, VLDPE indicates ultra-low density polyethylene, and LDPE indicates low density polyethylene.

(3) Manufacture of solar cell module About Examples 2-8, it carried out similarly to Example 1, and obtained the solar cell module. For Examples 9 and 10, a solar cell module was obtained in the same manner as in Example 1 except that thermocompression bonding with a vacuum laminator was performed at 170 ° C. for 15 minutes, and Example 11 was performed at 170 ° C. for 30 minutes. .
[Comparative Example 1]
The procedure was the same as Example 1 except that the silane-modified resin was not used.
[Comparative Example 2]
The procedure was the same as Example 1 except that the master batch was not used.

[Comparative Examples 3 to 4]
It was the same as Example 1 except having obtained the filler layer for solar cell modules like Example 1 on the conditions shown in Table-2. In Example 1, 5 parts by weight of a master batch containing 1 part by weight of dibutyltin dilaurate was mixed with the silane-modified resin, LLDPE, light stabilizer, UVA, and antioxidant containing master batch described in Example 1. The film was added in the same manner as described above.

[Evaluation]
About the solar cell module filler layer obtained in Examples 1 to 11 and Comparative Examples 1 to 4, the total light transmittance was measured for the solar cell module filler layer after the solar cell module was manufactured. For the fraction, the filler removal state, and the solar cell module, the electromotive force reduction rate was measured under the following conditions. The evaluation results are shown in Table-3.

(Total light transmittance)
About the filler layer for solar cell modules, the total light transmittance was measured using the color computer. Specifically, the solar cell module filler layer sheet is sandwiched between front and back ethylenetetrafluoroethylene copolymer films (trade name: AFLEX100N, manufactured by Asahi Glass Co., Ltd.) and 150 ° C. at 15 ° C. with a vacuum laminator for manufacturing solar cell modules. After pressure-bonding for a minute, the said ethylene tetrafluoroethylene copolymer film was peeled and only the said filler layer sheet | seat for solar cell modules heated was measured.
(Glass adhesion)
After leaving the solar cell module in a high-temperature and high-humidity state at a temperature of 85 ° C. and a humidity of 85% for 1000 hours, the peel strength between the solar cell module filler layer and the transparent front substrate glass was measured.

(Gel fraction)
It measured using the method demonstrated in the column of the said "A. Solar cell module filler layer".
(Filler removal state)
A solar cell module was manufactured, and the solar cell element and the back surface protective sheet were separated from the transparent front substrate (glass plate) using a wire in silicone oil heated to 180 ° C. after cooling. Thereafter, the silicone oil was washed and removed, and the transparent front substrate (glass plate) with the filler layer remaining was placed on a hot plate maintained at 180 ° C., and the remaining filler layer was wiped off with a cloth. The ease of wiping at that time and the remaining state after wiping were evaluated.
(Electromotive force reduction rate)
Based on JIS standard C8917-1989, the environmental test of the solar cell module was performed, and the output of the photovoltaic power before and after the test was measured.

  As apparent from Table-3, the solar cell module filler layer of the example had good appearance and total light transmittance. In addition, regarding the peel strength from the glass, the appearance of the solar cell module of the example did not change even after being left for 1000 hours in a high-temperature and high-humidity state at a temperature of 85 ° C. and a humidity of 85%. The layer was in good condition without being easily peeled off from the glass. Furthermore, the rate of decrease in electromotive force of the solar cell module of the example was also good. On the other hand, the filler layer for a solar cell module of Comparative Example 1 did not use a silane-modified resin, so that it did not adhere to the glass, and the electromotive force reduction rate could not be evaluated. Moreover, since the filler layer for solar cell modules of Comparative Example 2 did not use a master batch, yellowing was observed when left for 1000 hours in a high-temperature and high-humidity state at a temperature of 85 ° C. and a humidity of 85%.

It is a schematic sectional drawing which shows an example of the solar cell module of this invention.

Explanation of symbols

2 ... Solar cell module filler layer T ... Solar cell module

Claims (7)

A solar cell module filler layer having a silane-modified resin obtained by polymerizing an ethylenically unsaturated silane compound and polymerization polyethylene, and the gel layer when the solar cell module filler layer is used in a solar cell module A filler layer for a solar cell module, wherein the fraction is 30% or less. The solar cell module filler layer according to claim 1, wherein the solar cell module filler layer further includes polyethylene for addition. The polymerization polyethylene and the additive polyethylene are at least selected from the group consisting of low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, ultra-low-density polyethylene, and linear low-density polyethylene. The filler layer for a solar cell module according to claim 1 or 2, wherein the filler layer is one polyethylene. The quantity of the said silane modified resin contained in the said filler layer for solar cell modules exists in the range of 1 to 80 weight%, The claim in any one of Claim 1 to 3 characterized by the above-mentioned. The filler layer for solar cell modules described. 6. The solar cell module filler material according to claim 1, wherein Si (silicon) is contained in an amount of 8 to 3500 ppm as a polymerized Si amount. Solar cell module. The solar cell module filler according to any one of claims 1 to 5, wherein the solar cell module filler layer is substantially free of a silanol condensation catalyst. layer. A solar cell module comprising the solar cell module filler layer according to any one of claims 1 to 6.

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