JP6427871B2 - Solar cell module - Google Patents

Description

  The present invention relates to a solar cell module. More specifically, the present invention relates to a solar cell module having good edge adhesion and excellent moisture resistance and durability.

  In recent years, photovoltaic power generation has attracted a great deal of attention as an energy source that is clean and useful for preventing global warming, and has already begun to spread considerably. As a representative example of the solar power generation, a solar cell using a semiconductor such as single crystal silicon, polycrystalline silicon, amorphous silicon, and the like can be given. A solar cell is a practical application of the principle that current can be taken out when sunlight hits a semiconductor.

  A general solar cell has a transparent and strong glass substrate or resin substrate as a front surface, and an outer peripheral portion of a solar cell module in which a solar cell element is sealed using a sealing material and a back protection member (back sheet). A seal material and a metal frame are attached to each other, and a wiring, a terminal BOX and the like are further connected.

  In such a solar cell module, it is important that the solar cell elements used in various outdoor environments do not suffer damage or a decrease in insulation over a long period of time. In addition, moisture resistance at low temperatures is required. Further, it is preferable that appearance defects such as contamination and corrosion of the solar cell element and the wiring portion due to components contained in the sealing material, bubbles in the module, and swelling of the protective member do not occur. Here, with respect to moisture resistance, the influence of moisture intrusion from the side of the module is large, especially damage or damage to the solar cell element due to moisture penetration due to insufficient adhesion or adhesion at the interface between other members and the sealing material. There was a problem of causing a decrease in insulation.

  For these problems, for example, Patent Document 1 and Patent Document 2 disclose a solar cell module in which the confidentiality of the side surface is improved by forming the side surface with a protective member or the like. As a result, as compared with the conventional module as shown in FIG. 7 of Patent Document 2, a means for suppressing long-term durability by suppressing peeling from the end portion and intrusion of moisture has been proposed.

Japanese Patent Laid-Open No. 10-233521 JP 2001-267596 A

However, in Patent Documents 1 and 2, since the shape and configuration of the solar cell module are significantly different from those of the conventional solar cell module, it is necessary to add a molding process or change the size of the member used. In addition, the peripheral members such as the frame and the terminal BOX need to be changed to a special configuration, which may cause problems in terms of manufacturing, member costs, and the like.
The problem of the present invention is that the end part adhesion between the protective member and the sealing material is excellent and the moisture resistance and durability are excellent, without adding a molding process of the solar cell module or drastically changing the member size to be used. Another object is to provide a solar cell module.

As a result of intensive studies, the inventors of the present invention have provided at least a front protective layer, a sealing material layer, and a back protective layer in this order, and a solar cell module in which a solar cell element is sealed. It has been found that a solar cell module having a specific thickness ratio of layers has good edge adhesion and is excellent in moisture resistance and durability, and has completed the present invention.
That is, the present invention relates to the following [1] to [8].

[1] In a solar cell module having at least a front protective layer (A), a sealing material layer (B), and a back protective layer (C) in this order, and the solar cell element being sealed, A sealing material in which the long side L is 100 mm or more and the distance M in the in-plane direction from the end when the short side of the solar cell module is the end with respect to the long side L is 0 mm or more and 5 mm or less. The thickness ratio d / D between the maximum thickness d of the layer (B) and the average thickness D of the sealing material layer (B) in the range of 0.1 L ≦ M ≦ 0.5 L is 0.70 ≦ d / D ≦. The solar cell module which is 1.0.
[2] The solar cell module according to [1], wherein a storage elastic modulus at a vibration frequency of 10 Hz and a temperature of 20 ° C. in the dynamic viscoelasticity measurement of the back protective layer (C) is 2.0 GPa or more.
[3] The gel fraction of the sealing material layer (B) calculated from the mass of the xylene-insoluble matter measured by ASTM-2765-95 is less than 30%, as described in [1] or [2] above Solar cell module.
[4] The gel fraction of the sealing material layer (B) calculated from the mass of the xylene-insoluble matter measured by ASTM-2765-95 is less than 10%, as described in [1] or [2] above Solar cell module.
[5] The gel fraction of the sealing material layer (B) calculated from the mass of the xylene-insoluble matter measured by ASTM-2765-95 is less than 1%, as described in [1] or [2] above Solar cell module.
[6] The solar cell module according to any one of [1] to [5], wherein the sealing material layer (B) is made of a resin composition containing an olefin resin as a main component.
[7] The sealing material layer (B) according to any one of [1] to [6], wherein a melt flow rate at a temperature of 190 ° C. and a load of 21.18 N is 0.5 to 20 g / 10 minutes. Solar cell module.
[8] A method for manufacturing a solar cell module according to any one of [1] to [7] above, wherein at least the front protective layer (A), the sealing material layer (B), the solar cell element, and the back surface protection The manufacturing method of a solar cell module which has the process of laminating | stacking a layer (C) to make a laminated body, and vacuum-sucking this laminated body, and laminating | stacking on the conditions of the lamination temperature of 100-145 degreeC and the pressure of 30-100 kPa.

  According to the present invention, it is possible to provide a solar cell module that has good edge adhesion and excellent moisture resistance and durability without adding a solar cell module molding step or making a significant change in the size of a member used.

It is a schematic sectional drawing which shows an example of the solar cell module of this invention. It is a schematic plan view which shows an example of the solar cell module of this invention. It is the schematic which shows the measuring method of edge part peeling amount. It is the schematic which shows the preparation methods of the test sample for adhesive evaluation.

  Hereinafter, examples of embodiments of the solar cell module of the present invention will be described. However, the scope of the present invention is not limited to the embodiments described below.

  In the present specification, “main component” is intended to allow other components to be included within a range that does not interfere with the action and effect of the resin constituting each member of the solar cell module of the present invention. is there. Further, this term does not limit the specific content, but it is 50% by mass or more, preferably 65% by mass or more, more preferably 80% by mass or more of the total components of the resin composition. It is a component occupying a range of mass% or less.

[Solar cell module]
The solar cell module of this invention is a solar cell module which has a front surface protective layer (A), a sealing material layer (B), and a back surface protective layer (C) in order, and the solar cell element was sealed. The sealing material layer (B) is located between the front protective layer (A) and the back protective layer (C) and is in contact with at least one surface of the solar cell element from the viewpoint of protecting the solar cell element. Just do it. As a configuration of such a solar cell module, for example, a configuration of front protective layer (A) / sealing material layer (B) / solar cell element / back surface protective layer (C), front protective layer (A) / solar cell Device / sealing material layer (B) / back surface protective layer (C), front surface protective layer (A) / sealing material layer (B1) / solar cell element / sealing material layer (B2) / back surface protective layer ( C) and the like. In the case where the sealing material layer (B) is composed of a sealing material layer on the front protective layer (A) side and a sealing material layer on the rear protective layer (C) side, the front protective layer (A) side (B1), the sealing material layer on the back protective layer (C) side is (B2), and the entire laminated structure of (B1) and (B2) is referred to as “sealing material layer (B)”. Called. Further, in this specification, for example, the notation A / B / C indicates that layers are stacked in the order of A, B, and C from the top (or from the bottom).
From the viewpoint of protecting the solar cell element, the solar cell module of the present invention has the front protective layer (A) / sealing material layer (B1) / solar cell element / sealing material layer (B2) / back surface protective layer (C ) Is preferable.
A schematic cross-sectional view of the solar cell module having such a configuration is shown in FIG. In FIG. 1, a solar cell module 100 of the present invention includes a front protective layer (A) 10, a sealing material layer (B1) 12A, solar cell elements 14A and 14B, and a sealing material layer (B2) in order from the sunlight receiving side. ) 12B and the back surface protective layer (C) 16 are laminated, and further, a junction box 18 (terminal for connecting wiring for taking out the electricity generated from the solar cell element to the outside) on the bottom surface of the back surface protective layer (C) 16 Box). The solar cell elements 14A and 14B are connected by a wiring 20 in order to conduct the generated current to the outside. The wiring 20 is taken out to the outside through a through hole (not shown) provided in the back surface protection layer (C) 16 and connected to the junction box 18.

The solar cell module of the present invention has a long side L of 100 mm or more, and a distance M in the in-plane direction from the end when the short side of the solar cell module is an end with respect to the long side L is 0 mm. The thickness ratio d / D between the maximum thickness d of the sealing material layer (B) in the range of 5 mm or less and the average thickness D of the sealing material layer (B) in the range of 0.1 L ≦ M ≦ 0.5 L is 0.70 ≦ d / D ≦ 1.0.
FIG. 2 is a schematic plan view showing an example of the solar cell module of the present invention. In FIG. 2, L is a long side of the solar cell module 100, A is a short side of the solar cell module, and an end portion with respect to the long side L. M1 represents a distance in the in-plane direction of 5 mm from the end A.
A range X shown in FIG. 2 indicates a range in which the distance M in the in-plane direction from the end A of the solar cell module is 0 mm or more and 5 mm or less, and the maximum thickness of the sealing material layer (B) in the range is d. It is. In addition, a solar cell element and wiring are normally arrange | positioned in parts other than the range whose distance M to the in-plane direction from the edge part A of a solar cell module is 0 mm or more and 5 mm or less.
In addition, the distance M in the in-plane direction from the end A is in the range of 0.1 L ≦ M ≦ 0.5 L. The distance from the one end (short side) of the solar cell module 100 in the in-plane direction. M means a range in which the range of 0.1L to 0.5L and the distance M in the in-plane direction from the other end (short side) is the sum of the ranges of 0.1L to 0.5L, Specifically, this is the range indicated by Y in FIG. The average thickness of the sealing material layer (B) in this range is D.
The maximum thickness d and the average thickness D can be observed and measured by observing the module cross section with an optical microscope. Specifically, the maximum thickness d and the average thickness D can be measured by the method described in Examples. The average thickness D is an average value when the thicknesses at the positions of 0.1 L, 0.3 L, 0.5 L, 0.7 L, and 0.9 L are measured from one end in the range indicated by Y in FIG. is there.

In the solar cell module of the present invention, the thickness ratio d / D between the maximum thickness d and the average thickness D of the sealing material layer (B) is 0.70 ≦ d / D ≦ 1.0. When the thickness ratio d / D is less than 0.70, the adhesiveness at the end of the module is insufficient, and the module is inferior in moisture resistance and durability. When the thickness ratio d / D is more than 1.0, the adhesion between the front protective layer (A), the sealing material layer (B), and the back protective layer (C) is lowered, and sealing is performed. There arises a problem that bubbles are likely to be generated inside the material layer (B).
The reason why the effect of the present invention can be obtained by adjusting the thickness ratio d / D to the above range is that the sealing material layer is maintained in a high thickness state, so that it can be sealed even at the end of the module that is easily peeled off. This is considered to be because the local load on the adhesive interface caused by deformation of the stopper is reduced and the adhesive strength can be maintained.
The thickness ratio d / D is preferably 0.75 or more, more preferably 0.78 or more, and further preferably, from the viewpoint of improving the end adhesion of the module and obtaining a solar cell module having excellent moisture resistance and durability. 0.80 or more. From the viewpoint of improving the adhesion between the layers, the thickness ratio d / D is preferably 0.98 or less, more preferably 0.95 or less, and still more preferably 0.90 or less.

Next, a method for controlling the thickness ratio d / D of the sealing material layer (B) will be described. Although there is no restriction | limiting in particular in the control method of thickness ratio d / D of a sealing material layer (B), (1) In manufacture of a solar cell module, a front surface protective layer (A), a sealing material layer (B), the sun In the step of laminating by laminating the battery element and the back surface protective layer (C), there is a method of adjusting at least the laminating temperature, preferably the laminating temperature and the pressure during laminating. Furthermore, (2) a method using a back protective layer having a vibration elastic modulus of 10 Hz and a storage elastic modulus at a temperature of 20 ° C. of 2.0 GPa or more as a back protective layer (C), and (3) a sealing material layer (B) at least one method selected from a method using a substantially non-crosslinked sealing material layer, and (4) a method of adjusting the melt flow rate (MFR) of the sealing material layer (B); More preferably, the method (1) is used in combination.
Said (1)-(4) is each explained in full detail in description of the following each member and the manufacturing method of a solar cell module.

Next, each member used for the solar cell module of this invention is demonstrated.
(Front protective layer (A))
Although it does not restrict | limit especially as a front surface protective layer (A) used for this invention, For example, board | plate materials, such as glass, an acrylic resin, a polycarbonate resin, a polyester resin, and a fluorine-containing resin, Single layers, such as said resin Or a multilayer film is mentioned. Examples of the glass plate material include white plate glass, tempered glass, double tempered glass, heat ray reflective glass, and white plate tempered glass. Generally, white plate tempered glass having a thickness of about 3 to 5 mm is used. In the present invention, a glass plate material from the viewpoint of economy and mechanical strength, and a plate material having an acrylic resin or polycarbonate resin thickness of about 5 mm from the viewpoint of lightness and workability are preferably used. As the glass plate material, embossed glass whose surface is embossed is also preferable from the viewpoint of increasing the utilization efficiency of sunlight.

(Sealing material layer (B))
The sealing material layer (B) used in the present invention is provided between the front protective layer (A) and the back protective layer (C) for the purpose of sealing and protecting the solar cell element. As described above, the sealing material layer (B) is in contact with at least one surface of the solar cell element, thereby sealing the solar cell element.

  The sealing material layer (B) used for this invention will not be restrict | limited especially if the thickness ratio mentioned later is satisfied. Specifically, an encapsulant layer mainly composed of ethylene-vinyl acetate copolymer (EVA), polyethylene (PE), polypropylene (PP), ionomer (IO), polyvinyl butyral (PVB), and the like can be given. In the present invention, an encapsulant layer mainly composed of at least one of olefin polymers, particularly olefin polymers shown in the following (b1) to (b4) is preferably used. Here, as the main component of the encapsulant layer (B), flexibility of the obtained encapsulant layer, little fish eye (gel), few corrosive substances (such as acetic acid) in the circuit, and economic efficiency From the standpoint of the above, those shown in (b1) or (b2) are preferred, and those shown in (b1) are more preferred because of their excellent low-temperature characteristics.

(B1)
(B1) is a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. These copolymerization forms (random, block, etc.), branching, branching degree distribution and three-dimensional structure are not particularly limited, and a polymer having an isotactic, atactic, syndiotactic or mixed structure thereof can be obtained. Here, as the α-olefin copolymerized with ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 3-methyl- Examples include butene-1, 4-methyl-pentene-1.
Propylene, 1-butene, 1-hexene, and 1-octene are preferably used as the α-olefin copolymerized with ethylene from the viewpoints of industrial availability, various characteristics, economy, and the like. Further, an ethylene-α-olefin random copolymer is preferably used from the viewpoint of transparency and flexibility. The α-olefin copolymerized with ethylene can be used alone or in combination of two or more.

  Further, the content of the α-olefin copolymerized with ethylene is not particularly limited, but all monomers in the copolymer (b1) of ethylene and an α-olefin having 3 to 20 carbon atoms. The monomer unit based on an α-olefin having 3 to 20 carbon atoms is usually 2 mol% or more, preferably 2 to 40 mol%, more preferably 3 to 30 mol%, and still more preferably 5 to the unit. ~ 25 mol%. Within such a range, the crystallinity is reduced by the copolymerization component, so that the transparency is improved and problems such as blocking of raw material pellets are less likely to occur. In addition, the kind and content of the monomer copolymerized with ethylene can be qualitatively quantitatively analyzed by a well-known method, for example, a nuclear magnetic resonance (NMR) measuring apparatus or other instrumental analyzers.

The copolymer (b1) of ethylene and an α-olefin having 3 to 20 carbon atoms may contain a monomer unit based on a monomer other than the α-olefin. Examples of the monomer include cyclic olefins, vinyl aromatic compounds (such as styrene), polyene compounds, and the like. The content of the monomer units is preferably 20 mol% or less when the total monomer units in the copolymer (b1) of ethylene and an α-olefin having 3 to 20 carbon atoms is 100 mol%. More preferably, it is 15 mol% or less.
The three-dimensional structure, branching, branching degree distribution and molecular weight distribution of the copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms are not particularly limited. The copolymer having such an advantage generally has good mechanical properties.

  The melt flow rate (MFR) of the copolymer (b1) of ethylene and an α-olefin having 3 to 20 carbon atoms used in the present invention is not particularly limited, but the end adhesion of the module is obtained. Therefore, from the viewpoint of controlling the thickness of the sealing material layer (B) within a predetermined range, and from the viewpoint of adhesion and ease of wrapping when the solar cell element (cell) is sealed, MFR (JIS K7210, Temperature: 190 ° C., load: 21.18 N) is about 0.1 to 100 g / 10 minutes, preferably 0.2 to 50 g / 10 minutes, more preferably 0.5 to 50 g / 10 minutes, and still more preferably 0. .5-30 g / 10 min.

  The production method of the copolymer (b1) of ethylene and an α-olefin having 3 to 20 carbon atoms is not particularly limited, and a known polymerization method using a known olefin polymerization catalyst can be employed. For example, a slurry polymerization method, a solution polymerization method, a gas phase polymerization method using a multi-site catalyst typified by a Ziegler-Natta type catalyst, a single site catalyst typified by a metallocene catalyst or a post-metallocene catalyst, etc. And a bulk polymerization method using a radical initiator. In the present invention, a polymerization method using a single-site catalyst capable of polymerizing a raw material having a low molecular weight component and a narrow molecular weight distribution is preferable from the viewpoints of easy granulation after pelletization and prevention of blocking of raw material pellets. is there.

The heat of crystal fusion measured at a heating rate of 10 ° C./min in the differential scanning calorimetry of the copolymer of ethylene and α-olefin having 3 to 20 carbon atoms used in the present invention is 0 to 70 J / g. It is preferable that Within this range, the flexibility and transparency (total light transmittance) of the obtained sealing material are ensured. Further, considering the difficulty of blocking the raw material pellets in a high temperature state such as summer, the heat of crystal melting is preferably 5 to 70 J / g, more preferably 10 to 65 J / g.
The heat of crystal fusion can be measured at a heating rate of 10 ° C./min according to JIS K7122 using a differential scanning calorimeter.

  Specific examples of the copolymer (b1) of ethylene and an α-olefin having 3 to 20 carbon atoms used in the present invention include trade names “Engage” and “affinity” manufactured by Dow Chemical Co., Ltd. “Affinity”, “Infuse”, trade name “Exact” manufactured by ExxonMobil Corp., trade names “TAFMER H”, “Tuffmer A” manufactured by Mitsui Chemicals, Inc. Examples thereof include “TAFMER A)”, “TAFMER P”, a trade name “LUCENE” of LG Chemical Co., Ltd., a trade name “Kernel” manufactured by Nippon Polyethylene Corporation, and the like.

(B2)
(B2) is a copolymer of propylene and another monomer copolymerizable with the propylene, or a homopolymer of propylene. However, these copolymerization forms (random, block, etc.), branching, branching degree distribution and three-dimensional structure are not particularly limited, and can be a polymer having an isotactic, atactic, syndiotactic or mixed structure. .
Examples of other monomers copolymerizable with propylene include ethylene, 1-butene, 1-hexene, 4-methyl-pentene-1, 1-octene and other α-olefins having 4 to 12 carbon atoms and divinylbenzene, Examples include dienes such as 1,4-cyclohexadiene, dicyclopentadiene, cyclooctadiene, and ethylidene norbornene.
In the present invention, ethylene and 1-butene are preferably used as the α-olefin copolymerized with propylene from the viewpoints of industrial availability, various characteristics, economy, and the like. Moreover, a propylene-alpha-olefin random copolymer is used suitably from viewpoints, such as transparency and a softness | flexibility. The monomer copolymerized with propylene can be used alone or in combination of two or more.

  Further, the content of other monomers copolymerizable with propylene is not particularly limited, but a copolymer of propylene and other monomers copolymerizable with the propylene (b2) The monomer units based on other monomers copolymerizable with propylene are usually 2 mol% or more, preferably 2 to 40 mol%, more preferably 3 to the total monomer units in 30 mol%, more preferably 5 to 25 mol%. Within such a range, the crystallinity is reduced by the copolymerization component, so that the transparency is improved and problems such as blocking of raw material pellets are less likely to occur. In addition, the kind and content of the other monomer copolymerizable with propylene can be qualitatively quantitatively analyzed by a known method, for example, a nuclear magnetic resonance (NMR) measuring device or other instrumental analyzer.

  The melt flow rate (MFR) of (b2) used in the present invention is not particularly limited, but the thickness of the sealing material layer (B) is set within a predetermined range in order to obtain end adhesion of the module. From the viewpoint of control and the viewpoint of adhesion and ease of wraparound when sealing a solar cell element (cell), MFR (JIS K7210, temperature: 210 ° C., load: 21.18 N) is usually 0.5. ˜100 g / 10 minutes, preferably 2-50 g / 10 minutes, more preferably 3-30 g / 10 minutes.

  The production method of (b2), which is a copolymer of propylene and another monomer copolymerizable with propylene, or a homopolymer of propylene used in the present invention is not particularly limited, and is publicly known. A known polymerization method using the above olefin polymerization catalyst can be employed. For example, a slurry polymerization method, a solution polymerization method, a gas phase polymerization method, etc. using a multi-site catalyst typified by a Ziegler-Natta type catalyst, a single site catalyst typified by a metallocene catalyst or a post metallocene catalyst, Examples thereof include a bulk polymerization method using a radical initiator. In the present invention, a polymerization method using a single-site catalyst capable of polymerizing a raw material having a low molecular weight component and a narrow molecular weight distribution is preferable from the viewpoints of easy granulation after pelletization and prevention of blocking of raw material pellets. is there.

  Specific examples of (b2) used in the present invention include propylene-butene random copolymers, propylene-ethylene random copolymers, propylene-ethylene-butene-1 copolymers, and the like. Are trade names “TAFMER XM”, “NOTIO”, Sumitomo Chemical Co., Ltd., “TAFFCELLEN”, and Prime Polymer Co., Ltd. “Prime TPO”, trade name “VERSIFY” manufactured by Dow Chemical Co., Ltd., trade name “VistaMAXX” manufactured by ExxonMobil Corp., and the like can be exemplified.

(B3)
(B3) is a metal salt of a copolymer composed of an α-olefin such as ethylene or propylene and an aliphatic unsaturated carboxylic acid (preferred metals are Zn, Na, K, Li, Mg, etc.).
Specific products include, for example, a trade name “HIMILAN” manufactured by Mitsui Chemicals, Inc., and a product name “AMPLIFY IO” manufactured by Dow Chemical Co., Ltd.

(B4)
(B4) is an ethylene-based copolymer composed of ethylene and at least one monomer selected from vinyl acetate, aliphatic unsaturated carboxylic acid, and aliphatic unsaturated monocarboxylic acid alkyl ester.
Specific examples include an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-acrylic acid ester copolymer, and an ethylene-methacrylic acid ester copolymer. Here, examples of the ester component include esters of alcohols having 1 to 8 carbon atoms such as methyl, ethyl, propyl, and butyl. In the present invention, the copolymer is not limited to the above-described two-component copolymer, but a three-component or more multi-component copolymer (for example, ethylene and an aliphatic unsaturated carboxylic acid and an aliphatic unsaturated copolymer) with a third component added. It may be a ternary or higher copolymer suitably selected from saturated carboxylic acid esters). Here, the content of monomer units copolymerized with ethylene is usually 5 to 35% by mass with respect to all monomer units in the copolymer.

  The sealing material layer (B) has a single layer or a laminated structure, but a laminated structure is preferable in order to achieve the properties required for the sealing material layer in a balanced manner. Here, the properties generally required for the sealing material layer include flexibility and impact resistance for protecting the solar cell element, heat resistance when the solar cell module generates heat, solar light to the solar cell element. For efficient delivery of light (total light transmittance, etc.), adhesion to various adherends (glass, back protective layer, etc.), durability, dimensional stability, flame resistance, water vapor barrier property, economy Sex and so on. Above all, importance is attached to the balance between flexibility, heat resistance and transparency, and economy.

(Crystal melting peak temperature of olefin polymer)
It is preferable that a sealing material layer (B) consists of a resin composition which has the olefin type polymer of (b1)-(b4) mentioned above as a main component.
The crystal melting peak temperature (Tm) of the olefin polymer as the main component is preferably less than 100 ° C., but an amorphous polymer that does not express the crystal melting peak temperature, that is, an amorphous polymer is also applicable ( Hereinafter, it includes an amorphous polymer and is referred to as an olefin polymer having a crystal melting peak temperature of less than 100 ° C.). Considering blocking of raw material pellets, the crystal melting peak temperature is preferably 30 to 95 ° C, more preferably 45 to 80 ° C, and further preferably 50 to 80 ° C.
Further, when emphasizing the flexibility of the sealing material layer (B), an olefin polymer having a crystal melting peak temperature (Tm) of 100 ° C. or higher is added to an olefin polymer having a crystal melting peak temperature (Tm) of less than 100 ° C. It is preferable to use a mixture. The upper limit of the crystal melting peak temperature (Tm) of the olefin polymer to be mixed is not particularly limited, but it is 145 in consideration of the thermal deterioration of the solar cell element (cell) and the lamination temperature at the time of manufacturing the solar cell module. It is about ℃. In this invention, since the lamination temperature at the time of producing a solar cell module can be lowered and the solar cell element (cell) is hardly thermally deteriorated, the upper limit of the crystal melting peak temperature (Tm) of the olefin polymer to be mixed. The value is preferably 130 ° C, more preferably 125 ° C.
When the sealing material layer (B) has a laminated structure, a layer in which an olefin polymer having a crystal melting peak temperature of 100 ° C. or higher is mixed with an olefin polymer having a crystal melting peak temperature of less than 100 ° C. It is preferable to have at least one layer, and it is more preferable that the layer having the largest component ratio in the stacked configuration is the above-described layer.

  Here, as reference values of the crystal melting peak temperature, general-purpose high-density polyethylene resin (HDPE) is about 130 to 145 ° C., and low-density polyethylene resin (LDPE) and linear low-density polyethylene (LLDPE) are about 100 to About 125 ° C, general-purpose homopolypropylene resin is about 165 ° C, and general-purpose propylene-ethylene random copolymer is about 130-140 ° C. The crystal melting peak temperature can be measured at a heating rate of 10 ° C./min according to JIS K7121 using a differential scanning calorimeter.

As described above, the sealing material layer (B) is composed of a resin composition containing an olefin polymer having a crystal melting peak temperature of less than 100 ° C. and an olefin polymer having a crystal melting peak temperature of 100 ° C. or higher. It is preferable to have at least one layer.
The content of both olefinic polymers in the resin composition is not particularly limited, but considering the flexibility, heat resistance, transparency, etc. of the resulting sealing material layer, both olefinic polymers The mixing (containing) mass ratio (olefin polymer having a crystal melting peak temperature of less than 100 ° C./olefin polymer having a crystal melting peak temperature of 100 ° C. or more) is preferably 99 to 50/1 to 50, more preferably Is 98 to 60/2 to 40, more preferably 97 to 70/3 to 30, particularly preferably 97 to 80/3 to 20, and most preferably 97 to 90/3 to 10. However, the total of both olefin polymers is 100 parts by mass. A mixed (contained) mass ratio within the above range is preferable because it tends to be a sealing material layer having a good balance of flexibility, heat resistance, transparency, and the like.

  The olefin polymer having a crystal melting peak temperature of 100 ° C. or higher to be mixed with the sealing material layer (B) may be appropriately selected in consideration of desired characteristics. In the present invention, heat resistance, flexibility and low temperature are selected. The ethylene-α-olefin block copolymer described below can be used because of its excellent balance of properties and the like.

<Ethylene-α-olefin block copolymer>
The block structure of the ethylene-α-olefin block copolymer is not particularly limited, but from the viewpoint of balancing such as flexibility, heat resistance, transparency, comonomer content, crystallinity, density, crystal A multi-block structure containing two or more segments or blocks having different melting peak temperatures (Tm) or glass transition temperatures (Tg) is preferable. Specific examples include a completely symmetric block, an asymmetric block, and a tapered block structure (a structure in which the ratio of the block structure gradually increases in the main chain). Regarding the structure and production method of the copolymer having the multi-block structure, International Publication No. 2005/090425 (WO2005 / 090425), International Publication No. 2005/090426 (WO2005 / 090426), and International Publication No.2005. / 090427 pamphlet (WO2005 / 090427) or the like can be employed.

Next, the ethylene-α-olefin block copolymer having the multi-block structure will be described in detail below.
The ethylene-α-olefin block copolymer having a multiblock structure can be suitably used in the present invention, and an ethylene-octene multiblock copolymer having 1-octene as a copolymerization component as an α-olefin is preferable. As the block copolymer, an almost non-crystalline soft segment copolymerized with a large amount of octene component (about 15 to 20 mol%) with respect to ethylene and a small amount of octene component with respect to ethylene (about 2 mol%). Less) a multiblock copolymer in which two or more highly crystalline hard segments each having a copolymerized crystal melting peak temperature of 110 to 145 ° C. are present. By controlling the chain length and ratio of these soft segments and hard segments, both flexibility and heat resistance can be achieved.
As a specific example of the copolymer having the multi-block structure, trade name “Infuse” manufactured by Dow Chemical Co., Ltd. may be mentioned.

  On the surface of the sealing material layer (B) used in the present invention, solar cell modules such as handling properties and ease of air bleeding, adhesion to various adherends (glass, back protective layer, solar cells, etc.), etc. An important function as a sealing material is required. Therefore, in the present invention, as the sealing material layer (B), the above-described (b1) to (b4) to which a silane coupling agent described later is added or a resin obtained by mixing the following silane-modified ethylene resin A composition is preferably used. When the sealing material layer (B) has a laminated structure, it is preferable to have at least one layer composed of a resin composition obtained by mixing the above-described (b1) to (b4) with a silane-modified ethylene-based resin. Moreover, when a sealing material layer (B) is comprised from 2 or more sealing material layers, it is more preferable that the layer by the side of a contact surface with a solar cell element and glass is the said layer. For example, when the front protective layer (A) is glass, the sealing material layer (B1) on the front protective layer (A) side is preferably the above layer.

(Silane-modified ethylene resin)
The silane-modified ethylene resin used in the present invention can be usually obtained by melt-mixing a polyethylene resin, a vinylsilane compound, and a radical generator at a high temperature (about 160 ° C. to 220 ° C.) and graft polymerization.

<Polyethylene resin>
Although it does not restrict | limit especially as said polyethylene-type resin, Specifically, a low density polyethylene, a medium density polyethylene, a high density polyethylene, an ultra-low density polyethylene, or a linear low density polyethylene is mentioned. These can be used alone or in combination of two or more, and in particular, the copolymer of ethylene and the α-olefin having 3 to 20 carbon atoms mentioned in the above (b1) is preferably used. Can do.

In the present invention, a polyethylene resin having a low density is preferably used because of its excellent transparency and flexibility. Specifically, low-density polyethylene resin are preferred density 0.850~0.930g / cm ^3, density is more preferably linear low density polyethylene 0.870~0.920g / cm ^3. Further, a low density polyethylene resin and a high density polyethylene resin can be used in combination. By using in combination, the balance of transparency, flexibility and heat resistance can be adjusted relatively easily.

<Vinylsilane compound>
The vinyl silane compound is not particularly limited as long as it is graft-polymerized with the above polyethylene resin. For example, vinyl trimethoxy silane, vinyl triethoxy silane, vinyl tripropoxy silane, vinyl triisopropoxy silane, vinyl tri Examples include butoxysilane, vinyltripentyloxysilane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltrimethylenedioxysilane, vinyltriethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane, and vinyltricarboxysilane It is done. These vinyl silane compounds can be used alone or in combination of two or more. In the present invention, vinyltrimethoxysilane is preferably used from the viewpoints of reactivity, adhesiveness and color tone.

  The amount of the vinylsilane compound added is not particularly limited, but is usually about 0.01 to 10.0 parts by weight, preferably 0.3 to 100 parts by weight of the polyethylene resin used. It is 8.0 mass parts, More preferably, it is 1.0-5.0 mass parts.

<Radical generator>
Although it does not restrict | limit especially as a radical generator, For example, hydroperoxides, such as diisopropylbenzene hydroperoxide and 2, 5- dimethyl- 2, 5- di (hydroperoxy) hexane; -Butyl peroxide, t-butyl cumyl 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-dichlorobenzoylper Diacyl peroxides such as oxides; t-butyl pero Siacetate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxypivalate, t-butyl peroxy octoate, t-butyl peroxyisopropyl carbonate, t-butyl peroxybenzoate, di-t -Peroxyesters such as butyl peroxyphthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexyne-3; Examples include organic peroxides such as ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, or azo compounds such as azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile). These radical generators can be used alone or in combination of two or more.

  The amount of radical generator added is not particularly limited, but is usually about 0.01 to 5.0 parts by weight, preferably 0.02 to 100 parts by weight of the polyethylene resin used. 1.0 part by mass, more preferably 0.03 to 0.5 part by mass. Furthermore, the residual amount of the radical generator is preferably 0.001% by mass or less in the resin composition constituting the sealing material layer (B) used in the present invention. When such a radical generator remains in the resin composition, gelation may be caused by heating. In addition, gelation may include not only the presence of the radical generator in the encapsulant layer but also partly gelated when the encapsulant layer is produced. Since the fluidity of the stopping material layer is hindered and the reliability of the solar cell module is impaired, the gelation should be less. Therefore, the gel fraction of the resin composition constituting the sealing material layer (B) used in the present invention is preferably less than 30%, more preferably less than 10%, and more preferably less than 5%. More preferably, it is particularly preferably 0%.

It is preferable that the sealing material layer (B) of this invention does not contain substantially the silanol condensation catalyst which accelerates | stimulates the condensation reaction between silanols. Specific examples of the silanol condensation catalyst include dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctate, dioctyltin dilaurate and the like.
Here, substantially not containing is usually 0.05 parts by mass or less, preferably 0.03 parts by mass or less, with respect to 100 parts by mass of the resin composition constituting the sealing material layer (B). More preferably, it is 0.00 part by mass.

  The reason why it is preferable not to substantially contain a silanol condensation catalyst is that, in the present invention, the silanol crosslinking reaction is not allowed to proceed actively, and the polar group such as a silanol group grafted to the polyethylene resin to be used is attached. Bonded by interaction such as hydrogen bonding or covalent bonding with body (glass, various plastic sheets (appropriate surface treatment such as corona treatment, wetting index of 50 mN / m or more is preferably used), metal, etc.) This is to express sex.

  As a specific example of the silane-modified ethylene resin used in the present invention, trade name “LINKLON” manufactured by Mitsubishi Chemical Corporation can be exemplified.

(Additive)
Various additives can be added to the resin composition constituting the encapsulant layer (B) used in the present invention, if necessary. Examples of the additive include a silane coupling agent, an antioxidant, an ultraviolet absorber, a weathering stabilizer, a light diffusing agent, a heat radiating agent, a nucleating agent, a pigment (for example, titanium oxide, carbon black), and a flame retardant. And discoloration inhibitors. In the present invention, the resin composition constituting the encapsulant layer (B) contains at least one additive selected from a silane coupling agent, an antioxidant, an ultraviolet absorber, and a weather resistance stabilizer. This is preferable for reasons described later.
In the present invention, it is not necessary to add a crosslinking agent or a crosslinking aid to the resin composition constituting the encapsulant layer (B), but this does not exclude the addition of, for example, a high heat resistance. When properties are required, a crosslinking agent and / or a crosslinking aid can be blended.

<Silane coupling agent>
The silane coupling agent is useful for improving the adhesiveness to the protective material (front protective layer (A), back protective layer (C), etc.) of the sealing material layer (B), the solar cell element, and the like. Examples include compounds having a hydrolyzable group such as an alkoxy group in addition to an unsaturated group such as a vinyl group, an acryloxy group, and a methacryloxy group, an amino group, an epoxy group, and the like.
As the silane coupling agent, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ Examples thereof include glycidoxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane. These silane coupling agents can be used alone or in combination of two or more. In the present invention, γ-glycidoxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane are preferably used because of good adhesiveness and less discoloration such as yellowing.
The addition amount of the silane coupling agent is usually about 0.1 to 5 parts by mass, preferably 0.2 to 3 parts per 100 parts by mass of the resin composition constituting the encapsulant layer (B). Part by mass. In addition, similar to the silane coupling agent, a coupling agent such as an organic titanate compound can be effectively used.

(Antioxidant)
As the antioxidant, various commercially available products can be applied, and various types such as monophenol type, bisphenol type, polymer type phenol type, sulfur type and phosphite type can be exemplified.
Examples of monophenols include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, and the like. Examples of the bisphenol include 2,2v-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4 ′. -Thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidene-bis- (3-methyl-6-tert-butylphenol), 3,9-bis [{1,1-dimethyl-2 -{Β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl} 2,4,9,10-tetraoxaspiro] 5,5-undecane and the like can be exemplified.

  Examples of the high molecular phenolic compound include 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris ( 3,5-di-tert-butyl-4-bidoxybenzyl) benzene, tetrakis- {methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate} methane, bis {(3,3′-bis-4′-hydroxy-3′-tert-butylphenyl) butyric acid} glycol ester, 1,3,5-tris (3 ′, 5′-di-tert-butyl- Examples include 4′-hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione, tocopherol (vitamin E) and the like.

  Examples of sulfur-based compounds include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiopropionate.

The phosphite system includes triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, Crick neopentanetetrayl bis (octadecyl phosphite), tris (mono and / or di) phenyl phosphite, diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10 -Dihydro-9-oxa-10-phospha Phenanthrene, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-tert-methylphenyl) phosphite, 2,2- Examples thereof include methylene bis (4,6-tert-butylphenyl) octyl phosphite.
The said antioxidant can be used individually by 1 type or in combination of 2 or more types.

In the present invention, monophenolic, bisphenolic, polymeric phenolic and other phenolic and phosphite antioxidants are preferably used in view of the effects of antioxidants, thermal stability, economy, etc. More preferably, they are used in combination.
The addition amount of the antioxidant is usually about 0.1 to 1 part by mass, preferably 0.2 to 0. 1 part by mass with respect to 100 parts by mass of the resin composition constituting the encapsulant layer (B). 5 parts by mass.

<Ultraviolet absorber>
As the ultraviolet absorber, various commercially available products can be applied, and various types such as benzophenone, benzotriazole, triazine, and salicylic acid ester can be exemplified.
Examples of the benzophenone ultraviolet absorber include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n-dodecyl. Oxybenzophenone, 2-hydroxy-4-n-octadecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-5-chlorobenzophenone, 2,4 Examples include -dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone.

Benzotriazole-based UV absorbers include hydroxyphenyl-substituted benzotriazole compounds, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-t-butylphenyl) benzotriazole 2- (2-hydroxy-3,5-dimethylphenyl) benzotriazole, 2- (2-methyl-4-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-3-methyl-5-t-butylphenyl) ) Benzotriazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole and the like.
Examples of the triazine ultraviolet absorber include 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 2- (4 , 6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol and the like.
Examples of salicylic acid esters include phenyl salicylate and p-octylphenyl salicylate.
The said ultraviolet absorber can be used individually by 1 type or in combination of 2 or more types.

  The amount of the ultraviolet absorber added is usually about 0.01 to 2.0 parts by weight, preferably 0.05 to 100 parts by weight of the resin composition constituting the sealing material layer (B). 0.5 parts by mass.

<Weather resistance stabilizer>
A hindered amine light stabilizer is suitably used as a weather stabilizer that imparts weather resistance in addition to the above ultraviolet absorber. A hindered amine light stabilizer does not absorb ultraviolet rays like an ultraviolet absorber, but exhibits a remarkable synergistic effect when used together with an ultraviolet absorber. Other than the hindered amines, there are those that function as a light stabilizer, but they are often colored and are not preferable for the sealing material layer (B) used in the present invention.

  Examples of hindered amine light stabilizers include dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1 , 3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {{2, 2,6,6-tetramethyl-4-piperidyl} imino}], N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2, 6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3 , 5-Di-tert-4- Mud alkoxybenzylacetic) -2-n-butyl malonic acid bis (1,2,2,6,6-pentamethyl-4-piperidyl), and others. The said hindered amine light stabilizer can be used individually by 1 type or in combination of 2 or more types.

  The amount of the hindered amine light stabilizer added is usually about 0.01 to 0.5 parts by mass, preferably 0, with respect to 100 parts by mass of the resin composition constituting the encapsulant layer (B). 0.05 to 0.3 parts by mass.

When the sealing material layer (B) is composed of the above-mentioned sealing material layer (B1) on the front protective layer (A) side and the sealing material layer (B2) on the back protective layer (C) side The same resin composition may be used for (B1) and (B2), or different types of resin compositions may be used.
Since the sealing material layer (B2) used on the back protective layer (C) side is located on the back side of the solar cell element, it is more transparent (total light than the sealing material layer (B1) used on the front protective layer (A) side. (Transmittance) may not be very important. Further, when a white pigment is contained in the encapsulant layer (B2) and the light incident from the front protective layer side of the solar cell module is transmitted through the solar cell element for a part of the light, the light is reflected. It is also a preferable form to provide light reflectivity mainly for the purpose of re-entering the solar cell element and effectively using light. Furthermore, the designability and decorativeness of the solar cell module can be improved by imparting light-shielding properties by various colors such as blackening and bluening.

Here, examples of the white pigment include metal oxides such as titanium oxide, zinc oxide, silicon oxide, and aluminum oxide, and inorganic compounds such as calcium carbonate and barium sulfate. These white pigments can be used alone or in combination of two or more. In the present invention, titanium oxide, zinc oxide, and calcium carbonate can be suitably used. In particular, titanium oxide is preferably used because it can efficiently impart light reflectivity with a small amount of addition.
In order to improve the power generation efficiency by light reflection, the average value of the reflectance at 500 to 700 nm with the absorption intensity of a general solar cell is preferably 50% or more, more preferably 70% or more. Preferably, it is 80% or more, more preferably 90% or more.

In the present invention, it is preferable that the sealing material layer (B) is not substantially crosslinked. Here, the gel fraction of the sealing material layer (B) calculated from the mass of the xylene insoluble matter measured by ASTM-2765-95 means that the sealing material layer (B) is not substantially crosslinked. It means less than 30%. The gel fraction of the sealing material layer (B) is preferably less than 10%, more preferably less than 5%, and even more preferably less than 1%.
When the encapsulant layer (B) is crosslinked, for example, the fluidity of the encapsulant layer (B) is controlled by adjusting the degree of crosslinking by preheating or the like, and then the laminating temperature or The thickness ratio d / D of the sealing material layer (B) can be adjusted by adjusting the lamination conditions such as the pressure during lamination. On the other hand, the sealing material layer (B) which is not substantially crosslinked does not require adjustment of the degree of crosslinking described above, and the resin composition used for the sealing material layer (B) is a crosslinking agent or the like. Because it does not contain volatile components, outgassing is also low, so solar cell elements and wiring parts are less likely to be contaminated and corroded, bubbles are not generated in the module, and the protective layer is not swollen. It can be set as a solar cell module.

The flexibility of the sealing material layer (B) is not particularly limited, and can be appropriately adjusted in consideration of the shape and thickness of the applied solar cell, the installation location, and the like.
For example, the storage elastic modulus (E ′) at a vibration frequency of 10 Hz and a temperature of 20 ° C. in the dynamic viscoelasticity measurement of the sealing material layer (B) is preferably 1 to 2000 MPa. Protection and flexibility of solar cell elements, handling properties, prevention of blocking between sheet surfaces, or weight reduction in solar cell modules (usually about 3 mm, thin film glass (about 1.1 mm) can be applied, or glassless In view of the applicable structure), it is more preferably 5 to 500 MPa, and further preferably 5 to 300 MPa.
The storage elastic modulus (E ′) is obtained by measuring a predetermined temperature range at a vibration frequency of 10 Hz using a viscoelasticity measuring device and obtaining a value at a temperature of 20 ° C.

  The heat resistance of the sealing material layer (B) is influenced by various characteristics (crystal melting peak temperature, crystal melting heat, MFR, molecular weight, etc.) of the olefin polymer to be used, and can be adjusted by appropriately selecting these. In particular, the crystal melting peak temperature and molecular weight of the olefin polymer are strongly influenced. Generally, a solar cell module may be heated to about 85 ° C. due to heat generated during power generation or radiant heat of solar light. However, if the crystal melting peak temperature is 100 ° C. or higher, the sealing used in the present invention. Since the heat resistance of a material layer (B) can be ensured, it is preferable.

  The MFR (JIS K7210, temperature: 190 ° C., load: 21.18 N) of the sealing material layer (B) is about 0.1 to 20 g / 10 minutes, preferably 0.2 to 10 g / 10 minutes. More preferably, it is 0.5 to 5 g / 10 minutes. When the MFR of the encapsulant layer (B) is in the above range, the thickness ratio d / D of the encapsulant layer (B) can be easily controlled to a desired range, the end adhesiveness is good, and the moisture resistance and durability. It can be set as the solar cell module which is excellent in.

  The total light transmittance (JIS K7105) of the encapsulant layer (B) used in the present invention is the kind of the solar cell to be applied, for example, an amorphous thin film silicon type or a part that does not block sunlight reaching the solar electronic element. When applied, it may not be very important, but it is preferably 85% or more, preferably 88% or more in consideration of the photoelectric conversion efficiency of the solar cell and handling properties when overlapping various members. Is more preferable, and it is still more preferable that it is 90% or more.

About the softness | flexibility of the sealing material layer (B) used for this invention, heat resistance, and transparency, it becomes a contradictory property easily. Specifically, if the crystallinity of the resin composition used for improving flexibility is excessively lowered, the heat resistance is lowered and becomes insufficient. On the other hand, if the crystallinity of the resin composition used for improving the heat resistance is excessively improved, the transparency is lowered and becomes insufficient.
Considering these balances, the vibrational frequency 10 Hz and the storage elastic modulus (E ′) at a temperature of 20 ° C. in dynamic viscoelasticity measurement as an index of flexibility, and heating in differential scanning calorimetry for an olefin polymer as an index of heat resistance. In order to satisfy all of the flexibility, heat resistance and transparency when using the total light transmittance as the crystal melting peak temperature measured at a rate of 10 ° C./min and the transparency index, the above three indices However, it is preferable that the storage elastic modulus (E ′) is 1 to 2000 MPa, the crystal melting peak temperature is 100 ° C. or higher, and the total light transmittance is 85% or higher, and the storage elastic modulus (E ′) is 5 to 500 MPa. More preferably, the peak temperature is 102 to 150 ° C. and the total light transmittance is 85% or more, the storage elastic modulus (E ′) is 5 to 300 MPa, and the crystal melting peak temperature is 105 to 13. More preferably, it is 0 ° C. and the total light transmittance is 88% or more.

<Method for producing sealing material>
Next, the manufacturing method of the sealing material used for a sealing material layer (B) is demonstrated. The said sealing material consists of the above-mentioned resin composition, and the sealing material layer (B) has the sealing material layer (B1) by the side of the above-mentioned front protective layer (A), and the sealing by the side of a back protective layer (C). In the case where it is composed of the stopping material layer (B2), it is used as the sealing material layers (B1) and (B2), respectively.
The shape of the sealing material is not limited and may be liquid or sheet-like, but is preferably sheet-like from the viewpoint of handleability.
As a method for forming a sheet-like sealing material, a known method, for example, an extrusion casting method using a T-die, a calendar having a melt mixing facility such as a single screw extruder, a multi-screw extruder, a Banbury mixer, a kneader, etc. In the present invention, an extrusion casting method using a T die is preferably used from the viewpoints of handling properties and productivity. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film-forming properties of the resin composition used, but is generally 130 to 300 ° C, preferably 150 to 250 ° C.
The thickness of the sealing material is not particularly limited, but is usually 0.03 mm or more, preferably 0.05 mm or more, more preferably 0.1 mm or more, and usually 1 mm or less, preferably 0.7 mm or less. More preferably, it is 0.5 mm or less.

Various additives such as silane coupling agents, antioxidants, UV absorbers and weathering stabilizers may be dry blended with the resin in advance and then supplied to the hopper. May be supplied after being manufactured. It is also possible to prepare and supply a master batch in which only the additive is previously concentrated in the resin. In addition, on the surface and / or the back surface of the sealing material obtained in the form of a sheet, if necessary, the sheet can be used as a scroll to prevent blocking between sheets, and in the process of laminating solar cell elements, air handling properties and air Embossing and various unevenness (cone, pyramid shape, hemispherical shape, etc.) processing can be performed for the purpose of improving the ease of punching.
Further, for the purpose of improving the adhesion to various adherends, the surface can be subjected to various surface treatments such as corona treatment, plasma treatment and primer treatment. Here, as a standard of the surface treatment amount, the wet index is preferably 50 mN / m or more, and more preferably 52 mN / m or more. The upper limit of the wetting index is generally about 70 mN / m.

The encapsulant used in the present invention is a single layer or a laminated structure, but in order to achieve the properties required for the encapsulant as exemplified below in a balanced manner, from a plurality of layers having different composition contents and composition ratios. The laminated structure is preferably a laminated structure in which coextrusion is performed with a multilayer die using an extruder at that time.
Examples of the laminated structure composed of the plurality of layers include at least a laminated structure having a soft layer and a hard layer, which will be described later. For example, the following laminated structure is preferably used.
In this specification, for example, the notation A / B / C indicates that layers are stacked in the order of A, B, and C from the top (or from the bottom).
(1) Two types, three layers; specifically, soft layer / hard layer / soft layer, hard layer / soft layer / hard layer, adhesive layer / hard layer / adhesive layer, adhesive layer / soft layer / adhesive layer, Soft layer / recycled additive layer / soft layer, etc.
(2) 2 types, 2 layers; specifically, soft layer / hard layer, soft layer (I) / soft layer (II), adhesive layer / soft layer, adhesive layer / hard layer, soft layer (including additives) ) / Soft layer (without additive), Soft layer (with additive A) / Soft layer (with additive B) (additive formulation is different), etc.
(3) 3 types, 3 layers; specifically, soft layer / adhesive layer / hard layer, soft layer (I) / hard layer / soft layer (II), soft layer (I) / soft layer / soft layer ( II), adhesive layer (I) / hard layer / adhesive layer (II), adhesive layer (I) / soft layer / adhesive layer (II), etc.
(4) 3 types and 5 layers; specifically, soft layer / adhesive layer / hard layer / adhesive layer / soft layer, hard layer / adhesive layer / soft layer / adhesive layer / hard layer, soft layer / regeneration additive layer / Hard layer / regeneration additive layer / soft layer and soft layer / regeneration additive layer / hard layer / regeneration additive layer / hard layer.

In the present invention, from the viewpoint of balance between flexibility, heat resistance, transparency, and economy, soft layer / hard layer / soft layer, hard layer / soft layer / hard layer, adhesive layer / hard layer / adhesive layer, adhesion (1) Two types and three layers represented by layer / soft layer / adhesive layer, soft layer / regeneration additive layer / soft layer, etc. are preferably used. Of the two types and three-layer configuration of (1) above, the adhesive layer / soft layer / adhesive layer or soft layer / regeneration additive layer / soft layer is particularly preferable.
In addition, an intermediate | middle layer is a layer formed from the viewpoints, such as increasing the thickness of a sealing material and improving a desired performance, for example, is formed from the resin composition which has an olefin resin as a main component.
The regeneration additive layer is provided from the viewpoint of economic rationality and effective utilization of resources, and is formed from a resin composition that is regenerated and added with trimmings (ears) that occur during film formation of sealing materials and slit processing, for example. Layer.
The adhesive layer is provided from the viewpoint of improving adhesion to adjacent layers and adherends, such as carboxyl group, amino group, imide group, hydroxyl group, epoxy group, oxazoline group, thiol group and silanol group. It is a layer formed from a resin composition containing a resin modified with a polar group or a tackifying resin.
Examples of the additive include a silane coupling agent, an antioxidant, an ultraviolet absorber, a weathering stabilizer, a light diffusing agent, a heat radiating agent, a nucleating agent, a pigment, a flame retardant, a discoloration preventing agent, a crosslinking agent, and a crosslinking aid. Is mentioned.

  Here, the soft layer is a layer having a storage elastic modulus (E ′) at a vibration frequency of 10 Hz and a temperature of 20 ° C. in dynamic viscoelasticity measurement, preferably less than 100 MPa, more preferably 5 to 50 MPa. Is a layer having a storage elastic modulus (E ′) of preferably 100 MPa or more, more preferably 200 to 800 MPa. Of the two types and three layers of the above (1), in particular, an adhesive layer / soft layer / adhesive layer is preferably used. Adopting such a laminated structure is preferable because it is possible to relatively easily realize both the protection of the solar cell element and the adhesion between the front protective layer and the rear protective layer.

  The thickness of the soft layer in close contact with the solar cell element is not particularly limited, but is preferably 0.005 mm or more in consideration of the protection of the solar cell element, the wraparound property of the resin, and the like. More preferably, it is -0.6 mm. The thickness of each soft layer may be the same or different. Further, the thickness of the hard layer is not particularly limited, but is preferably 0.025 mm or more and 0.05 to 0.8 mm from the viewpoint of handling properties as a whole sealing material. More preferred.

When the sealing material used in the present invention is produced in a sheet shape, still another base film (for example, stretched polyester film (OPET), stretched polypropylene film (OPP) or ethylene-tetrafluoroethylene copolymer (ETFE). ), Polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), and various weathering films such as acrylic) and the like, and extrusion lamination, coextrusion, sand lamination, and the like.
By laminating the encapsulant layer (B) made of the encapsulant and various layers, it is possible to adjust the required characteristics and economy relatively easily according to improvement in handling properties and lamination ratio.

(Solar cell element)
The solar cell element used in the present invention is not particularly limited, but generally, at least one surface is disposed and wired in close contact with the sealing material layer (B).
For example, single crystal silicon type, polycrystalline silicon type, amorphous silicon type, gallium-arsenic, copper-indium-selenium, copper-indium-gallium-selenium, cadmium-tellurium, etc. III-V and II-VI group compound semiconductors Type, dye-sensitized type, and organic thin film type. In the present invention, single crystal silicon type and polycrystalline silicon type solar cells are preferably used.

(Back protective layer (C))
The back protective layer (C) used in the present invention is not particularly limited, but from the viewpoint of controlling the thickness ratio of the sealing material layer (B) to a specific range, the vibration frequency in dynamic viscoelasticity measurement is 10 Hz. The storage elastic modulus at a temperature of 20 ° C. is preferably 2.0 GPa or more. If the storage elastic modulus of the back protective layer (C) is 2.0 GPa or more, the front protective layer (A), the sealing material layer (B), and the back protective layer (C) are laminated and laminated. Therefore, it can be suppressed that the sealing material layer (B) flows out of the module and the thickness ratio d / D of the sealing material layer (B) is less than 0.70. The storage elastic modulus of the back protective layer (C) is preferably 2.2 GPa or more, more preferably 2.5 GPa or more, and further preferably 3.0 GPa or more.
The upper limit of the storage elastic modulus at a vibration frequency of 10 Hz and a temperature of 20 ° C. in the dynamic viscoelasticity measurement of the back protective layer (C) is not particularly limited, but is usually 5.0 GPa or less.

  Specific examples of the back protective layer (C) include polyester resins (polyethylene terephthalate (PET), polyethylene naphthalate (PEN), etc.), fluorine resins (polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroethylene). Fluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF) ) And polyvinyl fluoride (PVF)), polyolefin resin (polyethylene (PE), polypropylene (PP), various α-olefin copolymers, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate) Copolymer (EEA), ethylene-acrylic acid copolymer (EAA) and ethylene-methacrylic acid copolymer (EMAA)), cyclic olefin resin (COP, COC, etc.), polystyrene resin (acrylonitrile- Styrene copolymer (AS), acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene-acrylic rubber copolymer (ASA) and syndiotactic polystyrene (SPS)), polyamide (PA), polycarbonate ( PC), polymethyl methacrylate (PMMA), modified polyphenylene ether (modified PPE), polyphenylene sulfide (PPS), polyether sulfone (PES), polyphenyl sulfone (PPSU), polyether ether ketone (PEEK), Base sheet made of electrically insulating material such as polyetherimide (PEI), polyimide (PI) and biopolymer (polylactic acid, isosorbide polymer, polyamide polymer, polyester polymer, polyolefin polymer, etc.) (Or a substrate film).

In the present invention, a polyester resin, a polyolefin resin, and a fluorine resin are preferably used as the material for the base sheet from the viewpoints of adhesion to the sealing material layer (B), mechanical strength, durability, economy, and the like. Used. Here, the production method of the base sheet or base film is not particularly limited, but representative examples include an extrusion casting method, a stretching method, an inflation method, and a casting method.
Moreover, other resin and various additives can be mixed with a base material sheet as needed for the purpose of improvement, such as handling property, durability, and light reflectivity, or economical efficiency. Examples of the additive include an antioxidant, an ultraviolet absorber, a weathering stabilizer, a light diffusing agent, a nucleating agent, a pigment (for example, titanium oxide, barium sulfate, and carbon black), a flame retardant, a discoloration inhibitor, Examples include decomposition inhibitors and heat radiation agents.
Furthermore, on the surface and / or the back surface of the base sheet, embossing, various treatments (corona treatment, plasma treatment, etc.) and coating (fluorine) are performed as necessary in order to improve handling properties, adhesiveness and durability. Resin coating, hydrolysis prevention coating, hard coating, etc.).
The substrate sheet may be a single layer or a laminate composed of two or more layers.

The back protective layer (C) used in the present invention may have a structure in which a functional layer such as a barrier layer or an adhesive layer is further laminated on the base sheet, and balances the characteristics required for the back protective layer (C). In order to achieve well, it is preferable that it is a laminated structure.
Properties generally required for the back protective layer (C) include adhesion to the sealing material layer (B), mechanical strength, durability (such as weather resistance and hydrolysis resistance), light reflectivity, Water vapor barrier properties, flame retardancy, design properties, economics, appearance after lamination, etc., among others, in the case of crystalline silicon-based solar cell modules, adhesion to sealing materials, mechanical strength, durability, The economy and appearance after lamination are regarded as important.

For the back protective layer (C) used in the present invention, the following laminated structure is suitably used in order to achieve these characteristics in a balanced manner. Here, the adhesive layer to be described later is a layer mainly improving the adhesiveness between the respective layers of the back surface protective layer (C), and is not particularly limited. For example, a polyurethane adhesive or a polyester adhesive is used. An agent or a resin modified with a polar group can be preferably used. Moreover, the easy-adhesion layer to be described later is a layer mainly improving the adhesion to the sealing material, and is not particularly limited. For example, an ethylene-vinyl acetate copolymer, a polyethylene resin, or polypropylene is used. A resin or the like can be preferably used.
(1) Fluorine-based resin layer / adhesive layer / polyester resin layer / adhesive layer / easy-adhesive layer (sealing material side); specifically, PVF / adhesive layer / biaxially stretched PET / adhesive layer / EVA, PVF / Adhesive layer / biaxially stretched PET / adhesive layer / PE, PVF / adhesive layer / biaxially stretched PET / adhesive layer / PP, ETFE / adhesive layer / biaxially stretched PET / adhesive layer / EVA, ETFE / adhesive layer / biaxial Examples include stretched PET / adhesive layer / PE, ETFE / adhesive layer / biaxially stretched PET / adhesive layer / PP, and the like.
(2) Polyester resin layer / adhesive layer / polyester resin layer / adhesive layer / easy-adhesive layer (sealing material side); specifically, biaxially stretched PET (hydrolysis resistant prescription) / adhesive layer / biaxially stretched PET / Adhesive layer / EVA, biaxially stretched PET (hydrolysis resistant formulation) / adhesive layer / biaxially stretched PET / adhesive layer / PE, biaxially stretched PET (hydrolysis resistant formulation) / adhesive layer / biaxially stretched PET / adhesive Layer / PP, (surface coating) biaxially stretched PET / adhesive layer / biaxially stretched PET / adhesive layer / easy-adhesive layer, and the like.
(3) Polyester resin layer / adhesive layer / easy-adhesive layer (sealing material layer (B) side); specifically, biaxially stretched PET (hydrolysis resistant formulation) / adhesive layer / EVA, biaxially stretched PET ( Hydrolysis resistant formulation) / adhesive layer / PE, biaxially stretched PET (hydrolysis resistant formulation) / adhesive layer / PP, (surface coating) biaxially stretched PET / adhesive layer / easy adhesive layer, and the like.

  The adhesive layers (1) to (3) are arranged as necessary, and can be configured without an adhesive layer. Further, when importance is attached to the water vapor barrier property, for example, in the above-described biaxially stretched PET (hydrolysis resistant formulation) / adhesive layer / biaxially stretched PET / adhesive layer / PE configuration, Decomposition prescription) / adhesion layer / various vapor deposition layers (SiOx, alumina, etc.) / Biaxially stretched PET / adhesive layer / biaxially stretched PET / adhesive layer / PE can be used.

  The crystal melting peak temperature (Tm) of the easy adhesion layer is generally 80 ° C. or higher and 165 ° C. or lower. In the present invention, the crystal melting peak temperature (Tm) of the easy-adhesion layer is from the viewpoints of adhesion with the sealing material (D) and economics, the appearance of the solar cell module, the heat resistance of the easy-adhesion layer itself, and the like. The lower limit is preferably 95 ° C, more preferably 100 ° C. On the other hand, the upper limit is preferably 140 ° C, more preferably 125 ° C.

  The total thickness of the back surface protective layer (C) used in the present invention is not particularly limited and may be appropriately selected in consideration of desired performance, but is generally 50 μm or more and 600 μm or less, preferably 150 μm or more and 400 μm. It is as follows. Further, in order to satisfy the dielectric breakdown voltage of 1 kV or more, it is preferably 200 μm or more, and more preferably 250 μm or more.

[Method for manufacturing solar cell module]
In the method for producing a solar cell module of the present invention, the laminating temperature when laminating each member is usually 100 to 170 ° C., preventing thermal deterioration of the solar cell element (cell), and the end of the solar cell module. In order to improve the partial adhesiveness, the temperature is preferably 100 to 145 ° C, more preferably 100 to 140 ° C.
In the present invention, the “laminating temperature” is a set temperature of a laminator when the front protective layer (A), the sealing material layer (B), the solar cell element, and the back protective layer (C) are laminated and laminated. Yes, that is, the temperature of the heat source in the laminator device. A laminating temperature of 100 ° C. or higher is preferable because adhesion to the front protective layer (A) and the rear protective layer (C) can be obtained. On the other hand, if it is 145 degrees C or less, while suppressing the thermal deterioration of a solar cell element and making the edge part adhesiveness of a module favorable, it is preferable. It is also effective to perform the lamination in as short a time as possible in consideration of other characteristics (for example, vacuum suction time of 3 to 10 minutes, pressurization time of 1 to 10 minutes, etc.).
In the case of using a laminator having heat sources on both sides, the temperature of a heat source having a high temperature (hereinafter sometimes referred to as “high temperature heat source”) is not particularly limited, but is usually 100. It is about -170 degreeC, Preferably it is 100-145 degreeC, More preferably, it is 100-140 degreeC. Further, the temperature of the heat source having a low temperature when laminating is not particularly limited as long as it is lower than the temperature of the high temperature heat source.

  As a manufacturing method of the solar cell module of the present invention, a known manufacturing method can be applied except for the laminating temperature, and is not particularly limited, but at least the front protective layer (A), the sealing material layer (B), A step of laminating the solar cell element and the back surface protective layer (C) to form a laminated body, and vacuum-sucking the laminated body to remove bubbles between the layers of the laminated body, thereby forming a sealing material layer (B) In order to soften the resin, it is preferable to have a step of preheating (vacuum preheating) for 5 to 10 minutes as necessary and then laminating (thermocompression bonding) under conditions of a laminating temperature of 100 to 145 ° C. and a pressure of 30 to 100 kPa. In addition, the pressurization time at the time of lamination is usually about 1 to 30 minutes. By applying the above manufacturing method, thermal degradation of the solar cell element is prevented, the thickness ratio d / D of the sealing material layer (B) is controlled to a desired range, and the end portion adhesiveness is good and the moisture resistance is good. -A solar cell module having excellent durability can be obtained. Also, batch type manufacturing equipment, roll-to-roll type manufacturing equipment, and the like can be applied.

  The solar cell module of the present invention can be used in various applications regardless of indoors or outdoors, such as small solar cells represented by mobile devices and large solar cells installed on roofs and rooftops, depending on the type and module shape of the applied solar cells. Can be applied.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these examples and comparative examples. In addition, the measurement and evaluation of various physical properties of the back protective layer (back sheet), the sealing material, and the solar cell module in this example were performed as follows.

<Measurement of crystal melting peak temperature (Tm) and crystal melting heat (ΔHm)>
The crystal melting peak temperature (Tm) and the crystal melting calorie (ΔHm) of the encapsulant were measured using a differential scanning calorimeter (trade name: Pyris1 DSC, manufactured by PerkinElmer Co., Ltd.) in accordance with JIS K7121. About 10 mg of the sample was heated from −40 ° C. to 200 ° C. at a heating rate of 10 ° C./min, heated, held at 200 ° C. for 5 minutes, then cooled to −40 ° C. at a cooling rate of 10 ° C./min, The temperature was raised to 200 ° C. at a heating rate of 10 ° C./min. From the obtained thermogram, the crystal melting peak temperature (Tm), the crystal melting heat quantity (ΔHm), and the crystal melting heat quantity (ΔHm (≧ 100 ° C.)) of 100 ° C. or more (J / g) were determined.

<Measurement of gel fraction>
The gel fraction of the encapsulant layer of the modules produced in the examples and comparative examples in the present invention is the mass of xylene insolubles after Soxhlet extraction of the encapsulant at the boiling point of xylene based on ASTM-2765-95. % Was determined by measuring.

<Measurement of storage modulus>
The storage elastic modulus (E ′) at 20 ° C. of the sealing material and the back sheet used in the present invention was measured by a dynamic viscoelasticity measuring device (product name: Viscoelastic Spectrometer DVA-200, manufactured by IT Measurement Co., Ltd.). Measurement was performed in the TD direction by a measurement frequency of 10 Hz, a measurement temperature of −50 ° C. to 150 ° C., a strain of 0.1%, an interval between chucks of 25 mm, a heating rate of 3 ° C./min, and a tensile mode.

<Measurement of MFR>
The MFR (g / 10 minutes) of the sealing material constituting the sealing material layer and the resin constituting the sealing material is measured under the conditions of temperature: 190 ° C. and load: 21.18 N in accordance with JIS K7210. did.

<Measurement of end peel amount>
As shown in FIG. 3, the module 100 produced in the example and the comparative example has a 10 mm width × 75 mm length produced from a back protective layer member (back sheet) at one of the four corners on the back protective layer 16 side. A handle (30 in FIG. 3) was attached and left in a constant temperature and humidity chamber for 1 week under the conditions of a temperature of 85 ° C. and 85% RH. Then, the module was taken out, a pull gauge was attached to the handle, 180 ° peeling was performed with a load of 10 kgf, and the maximum peeling amount from the module end was measured using a metal ruler. Further, the amount of peeling at this time was evaluated according to the following criteria.
A: The amount of peeling between the glass and the sealing material layer is less than 10 mm. ○: The amount of peeling between the glass and the sealing material layer is 10 mm or more and less than 15 mm. X: The amount of peeling between the glass and the sealing material layer is 15 mm or more.

<Measurement of thickness ratio of sealing material layer>
Front protective layer member (150 mm × 150 mm embossed glass), sealing material, and back protective layer member (back sheet) used in each Example and Comparative Example, and release film (Mitsubishi Resin Co., Ltd., The product was laminated in the following order: embossed glass / release film / sealing material / cell / sealing material / back sheet. This was laminated under the conditions described in the examples and comparative examples to obtain test samples. The peripheral part of the test sample was trimmed to remove the protruding portion from the embossed glass, and the embossed glass and the release film were further removed to obtain a laminate composed of a sealing material / cell / sealing material / back sheet. .
This laminate is cut into two from the short central part, and the two layers of sealing material in the range of the distance from the end of the laminate to 5 mm at each of the two cut surfaces by optical microscope observation The maximum thickness d of the configured sealing material layer was measured. The distance from one end is 15 mm (= 0.1 L), 45 mm (= 0.3 L), 75 mm (= 0.5 L), 105 mm (= 0.7 L), and 135 mm (= 0.9 L). The total thickness of the sealing material layer excluding the thickness of the cell portion was measured at 10 points in total, and this average value was defined as the average thickness D. From the above value, the thickness ratio (d / D) was calculated.

<Adhesion evaluation>
As shown in FIG. 4A, using the embossed glass, the sealing material, the back sheet and the release film used in each example and comparative example, the embossed glass 101 / release film 401 / sealing material 121A / After laminating the sealing material 121B / back sheet 161 in this order, the laminate 200 was produced by laminating under the conditions of the respective examples and comparative examples (FIG. 4B). FIG. 4B is a schematic cross-sectional view of the laminate 200. Next, the release film was removed from the laminate 200 of Fig. 4B to obtain a laminate 300 ((Fig. 4C). In the laminate 300, the sealing material 121A / sealing material 121B / back sheet. 161 is the end portion on the side from which the release film is removed, and Z is cut into the laminated body 300 at intervals of 10 mm as shown in FIG. 4 (d), and the sealing material 121A / sealing material 121B / back sheet 161. (Dashed line portion in Fig. 4 (d)), 5 test samples 501 having a width of 10 mm were produced, and the test sample 501 was embossed within a range of a distance of 70 mm ± 10 mm from the end opposite to Z. It is in a state of being adhered to the glass 101. Using a universal tensile tester (manufactured by Intesco, model: 200X) so that the end Z of the test sample 501 can be gripped, a peel test (180 ° peel, test) The maximum value (maximum adhesive strength) was read in the peel test chart, and the adhesion between the embossed glass and the sealing material was evaluated according to the following criteria.
<Adhesion evaluation criteria>
A: The maximum adhesive strength was 40 N / 10 mm width or more.
X: The maximum adhesive strength was less than 40 N / 10 mm width.

<Outgas measurement>
For outgas measurement, a GC-MS device (manufactured by Shimadzu Corporation, model (GC): GC-17A, model (GC-MS): GCMS-QP5050A) and a headspace sampler (manufactured by Nippon Analytical Industries, Ltd., Model: JTD-505III) was used. Using the sample cut out to 10 mm × 10 mm by the double shot method for the encapsulant layer part used in the modules produced in the examples and comparative examples, outgas is detected when heated at 150 ° C. for 5 minutes, and the spectrum is detected. The outgas component was analyzed. Further, the outgas generation amount was calculated from the count number of outgas components. Table 2 shows the amount of outgas.
Note that the smaller the outgas amount, the less bubbles are generated when the temperature of the module rises, the swelling of the protective layer, etc., and the solar cell module is excellent in appearance.

<Preparation of sealing material 1>
The sealing material 1 has a two-type three-layer configuration in which (I) layer / (II) layer / (I) layer are laminated in this order. The resin composition (C-1) having the composition shown in Table 1 is used as the (I) layer, and the resin composition (C-2) having the composition shown in Table 1 is used as the (II) layer. After co-extrusion molding at a resin temperature of 180 to 200 ° C. by a T-die method using a same-direction twin screw extruder so as to be laminated in the order of layer / (II) layer / (I) layer, The film was rapidly cooled with a cast embossing roll to obtain a sealing material 1 ((I) layer / (II) layer / (I) layer = 45 μm / 360 μm / 45 μm) having a total thickness of 450 μm. Moreover, it evaluated as above-mentioned using the obtained sealing material 1. FIG. The results are shown in Table 2.

<Preparation of sealing material 2>
The sealing material 2 has a two-kind three-layer structure in which (I) layer / (II) layer / (I) layer are laminated in this order. The resin composition (C-3) having the composition shown in Table 1 is used as the (I) layer, and the resin composition (C-4) having the composition shown in Table 1 is used as the (II) layer. After co-extrusion molding at a resin temperature of 180 to 200 ° C. by a T-die method using a same-direction twin screw extruder so as to be laminated in the order of layer / (II) layer / (I) layer, The film was rapidly cooled with a cast embossing roll to obtain a sealing material 2 ((I) layer / (II) layer / (I) layer = 45 μm / 360 μm / 45 μm) having a total thickness of 450 μm. Moreover, it evaluated as above-mentioned using the obtained sealing material 2. As shown in FIG. The results are shown in Table 2.

<Preparation of sealing material 3>
The sealing material 3 has a two-kind three-layer structure in which (I) layer / (II) layer / (I) layer are laminated in this order. The resin composition (C-5) having the composition shown in Table 1 is used as the (I) layer, and the resin composition (C-6) having the composition shown in Table 1 is used as the (II) layer. After co-extrusion molding at a resin temperature of 180 to 200 ° C. by a T-die method using a same-direction twin screw extruder so as to be laminated in the order of layer / (II) layer / (I) layer, The film was rapidly cooled with a cast embossing roll to obtain a sealing material 3 ((I) layer / (II) layer / (I) layer = 45 μm / 360 μm / 45 μm) having a total thickness of 450 μm. Moreover, it evaluated as above-mentioned using the obtained sealing material 3. As shown in FIG. The results are shown in Table 2.

Details of the resin components shown in Table 1 are shown below.
PE-1: ethylene-octene random copolymer (“Tafmer H5030S” manufactured by Mitsui Chemicals, Inc., MFR: 5 g / 10 min, Tm: 59 ° C., ΔHm: 56 J / g, ΔHm (≧ 100 ° C.): 0 J / g)
PE-2: ethylene-octene block copolymer ("Infuse 9100" manufactured by Dow Chemical Co., Ltd.), MFR: 0.5 g / 10 min, Tm: 119 ° C, ΔHm: 45 J / g, ΔHm (≧ 100 ° C ): 41 J / g)
PE-3: ethylene-octene random copolymer (“Affinity EG8100” manufactured by Dow Chemical Co., Ltd., MFR: 1 g / 10 min, Tm: 59 ° C., ΔHm: 62 J / g, ΔHm (≧ 100 ° C.): 0 J / G)
SiR-1: Silane-modified polyethylene copolymer (“Ringlon SL800N” manufactured by Mitsubishi Chemical Corporation, MFR: 1.5 g / 10 minutes, Tm: 54 ° C. and 116 ° C., ΔHm: 45 J / g, ΔHm (≧ 100 ° C.): 5 J / g)
SiR-2: Silane-modified polyethylene copolymer (“Ringlon XLE815N” manufactured by Mitsubishi Chemical Corporation), MFR: 0.5 g / 10 min, Tm: 122 ° C., ΔHm: 22 J / g, ΔHm (≧ 100 ° C.) : 106J / g)

<Example 1>
150 mm x 150 mm embossed glass (Asahi Glass Co., Ltd., trade name: Solite, t = 3.2 mm) is used for the front protective layer, and the sealing material 1 cut to 153 mm x 160 mm is used for the sealing material. A 172 mm × 170 mm backsheet (trade name: Solmate TPE, thickness: 300 μm, hereinafter abbreviated as “BS-1”) was used for the layer. After laminating in the order of embossed glass / encapsulant 1 / cell / encapsulant 1 / back sheet, vacuum lamination was performed at 130 ° C. under conditions of vacuum preheating 5 minutes, pressurization 5 minutes, and pressure 100 kPa. L = 150 mm). Various evaluation results in this module are shown in Table 2.

<Example 2>
150 mm x 150 mm embossed glass (Asahi Glass Co., Ltd., trade name: Solite, t = 3.2 mm) is used for the front protective layer, and the sealing material 2 cut to 153 mm x 160 mm is used for the sealing material. A 172 mm × 170 mm backsheet (BS-1) was used for the layer. After laminating in the order of embossed glass / encapsulant 2 / cell / encapsulant 2 / backsheet, vacuum lamination was performed at 130 ° C. under conditions of vacuum preheating 5 minutes, pressurization 5 minutes, pressure 100 kPa, and solar cell module (L = 150 mm). Various evaluation results in this module are shown in Table 2.

<Example 3>
A solar cell module (L = 150 mm) was obtained in the same manner as in Example 2 except that the temperature during vacuum lamination was changed to 140 ° C. Various evaluation results in this module are shown in Table 2.

<Example 4>
A solar cell module (L = 150 mm) was obtained in the same manner as in Example 3 except that the sealing material 2 was changed to the sealing material 3. Various evaluation results in this module are shown in Table 2.

<Example 5>
150 mm x 150 mm embossed glass (Asahi Glass Co., Ltd., trade name: Solite, t = 3.2 mm) is used for the front protective layer, and the sealing material 1 cut to 153 mm x 160 mm is used for the sealing material. A 172 mm × 170 mm back sheet (trade name: Solmate VTPE, thickness 380 μm, hereinafter abbreviated as “BS-2”) was used for the layer. After laminating in the order of embossed glass / encapsulant 1 / cell / encapsulant 1 / backsheet, vacuum lamination was performed at 140 ° C. under conditions of vacuum preheating 5 minutes, pressurization 5 minutes, and pressure 100 kPa. = 150 mm). Various evaluation results in this module are shown in Table 2.

<Example 6>
A solar cell module (L = 150 mm) was obtained in the same manner as in Example 1 except that the pressing time during vacuum lamination was changed to 10 minutes. Various evaluation results in this module are shown in Table 2.

<Example 7>
A solar cell module (L = 150 mm) was obtained in the same manner as in Example 1 except that the temperature during vacuum lamination was changed to 140 ° C. and the pressure was changed to 30 kPa. Various evaluation results in this module are shown in Table 2.

<Example 8>
150mm x 150mm embossed glass (Asahi Glass Co., Ltd., trade name: Solite, t = 3.2mm) is used for the front protective layer, and EVA is 153mm x 160mm cut for the sealing material (manufactured by Bridgestone Corporation, Product name: EVASKY S11), and a back sheet (BS-1) of 172 mm × 170 mm was used for the back protective layer. By laminating embossed glass / EVA / cell / EVA / backsheet in this order, vacuum lamination at 140 ° C. under conditions of vacuum preheating for 10 minutes, pressure of 10 minutes, pressure of 30 kPa, followed by heat treatment at 160 ° C. for 15 minutes A solar cell module (L = 150 mm) was obtained. Table 2 shows the evaluation results of the sealing material layer (EVA) and various evaluation results in this module.

<Comparative Example 1>
A solar cell module (L = 150 mm) was obtained in the same manner as in Example 1 except that the temperature during vacuum lamination was changed to 160 ° C. Various evaluation results in this module are shown in Table 2.

<Comparative Example 2>
A solar cell module (L = 150 mm) was obtained in the same manner as in Example 1 except that the temperature during vacuum lamination was changed to 140 ° C. Various evaluation results in this module are shown in Table 2.

<Comparative Example 3>
150 mm x 150 mm embossed glass (Asahi Glass Co., Ltd., trade name: Solite, t = 3.2 mm) is used for the front protective layer, and the sealing material 2 cut to 153 mm x 160 mm is used for the sealing material. A 172 mm × 170 mm back sheet (trade name: ICOSOLAR AAA, thickness: 365 μm, hereinafter abbreviated as “BS-3”) was used for the layer. After laminating in the order of embossed glass / sealing material 2 / cell / sealing material 2 / backsheet, vacuum lamination was performed at 140 ° C. under conditions of vacuum preheating 5 minutes, pressure 5 minutes, pressure 100 kPa, and solar cell module (L = 150 mm). Various evaluation results in this module are shown in Table 2.

<Comparative example 4>
150mm x 150mm embossed glass (Asahi Glass Co., Ltd., trade name: Solite, t = 3.2mm) is used for the front protective layer, and EVA is 153mm x 160mm cut for the sealing material (manufactured by Bridgestone Corporation, Product name: EVASKY S11), and a back sheet (BS-1) of 172 mm × 170 mm was used for the back protective layer. After laminating in the order of embossed glass / EVA / cell / EVA / backsheet, the laminate was laminated at 160 ° C. under conditions of vacuum preheating for 5 minutes, pressurization for 15 minutes, and pressure of 100 kPa to obtain a solar cell module (L = 150 mm). Table 2 shows the evaluation results of the sealing material layer (EVA) and various evaluation results in this module.

  As is clear from the results in Table 2, the solar cell module of the present invention has a small edge peeling amount (Examples 1 to 8) and good edge adhesion between the front and back protective layers and the sealing material layer. It is. Therefore, it is possible to realize a solar cell module that is unlikely to cause a decrease in power generation efficiency due to moisture absorption and that has excellent long-term durability. In addition, the solar cell modules of Examples 1 to 7 produced less outgas and the like. Therefore, it is possible to realize a module in which appearance abnormality such as swelling due to temperature rise in an external environment and the like, and damage to wiring and solar cell elements are unlikely to occur. On the other hand, in the solar cell module that does not satisfy the requirements of the present invention, the end peeling amount was large (Comparative Examples 1 to 4).

  According to the present invention, it is possible to provide a solar cell module that has good edge adhesion and excellent moisture resistance and durability without adding a solar cell module molding step or making a significant change in the size of a member used.

10 ... Front protective layer (A)
12 ... Sealing material layer (B)
12A ・ ・ Encapsulant layer (B1)
12B ・ ・ Encapsulant layer (B2)
14A, 14B ... solar cell element 16 ... back protective layer (C)
18 ... Junction box 20 ... Wiring 30 ... Handle 100 ... Solar cell module 101 ... Embossed glass 121A, 121B ... Sealing material 161 ... Back sheet 200, 300 ... Laminate 401 ...・ Release film 501 ・ ・ Test sample for adhesion evaluation

Claims (5)

In a solar cell module having at least a front protective layer (A), a sealing material layer (B), and a back protective layer (C) in this order, and the solar cell element being sealed, the long side L of the solar cell module Is 100 mm or more, and when the short side of the solar cell module is the end with respect to the long side L, the distance M in the in-plane direction from the end is in the range of 0 mm to 5 mm. ) And a thickness ratio d / D between the average thickness D of the sealing material layer (B) in the range of 0.1 L ≦ M ≦ 0.5 L is 0.70 ≦ d / D ≦ 1.0. The average thickness D is a value obtained by measuring the thickness at each position of 0.1 L, 0.3 L, 0.5 L, 0.7 L, and 0.9 L from one end of the sealing material layer (B). the average value der of is,
The solar cell module whose gel fraction of the said sealing material layer (B) calculated from the mass of the xylene insoluble matter measured by ASTM-2765-95 is less than 1% .   The solar cell module according to claim 1, wherein a storage elastic modulus at a vibration frequency of 10 Hz and a temperature of 20 ° C in the dynamic viscoelasticity measurement of the back protective layer (C) is 2.0 GPa or more. The solar cell module according to claim 1 or 2 , wherein the sealing material layer (B) is made of a resin composition containing an olefin resin as a main component. Wherein the temperature 190 ° C. of the sealing material layer (B), a melt flow rate at a load 21.18N is 0.5 to 20 g / 10 min, a solar cell module according to any one of claims 1-3. It is a manufacturing method of the solar cell module in any one of Claims 1-4 , Comprising: At least a front surface protective layer (A), a sealing material layer (B), a solar cell element, and a back surface protective layer (C) are laminated | stacked. A method for producing a solar cell module, comprising: a step of forming a laminated body; and a step of vacuum-sucking the laminated body and laminating under a lamination temperature of 100 to 145 ° C. and a pressure of 30 to 100 kPa.