JP2018039865A - Solar cell module sealing material and solar cell module - Google Patents

Abstract

The present invention provides a solar cell module sealing material that can provide excellent PID resistance in a high-humidity environment and that can seal solar cells with high reliability, and a solar cell using the solar cell module sealing material. An object is to provide a battery module. A sealing material for a solar cell module. A plurality of solar cells 11, a pair of solar cell module encapsulants 12, a transparent protective material 13 and a back sheet 14, and at least one of the pair of solar cell module encapsulants 12 is made of ethylene-vinyl acetate. The solar cell module 10 which is a sealing material for solar cell modules containing a polymer (A), a tripropylene glycol diacrylate (B), and a functional group containing silane compound (C) in a specific ratio. [Selection] Figure 1

Description

  The present invention relates to a solar cell module sealing material and a solar cell module.

  As a solar cell module sealing material for sealing solar cells in a solar cell module, a material containing an ethylene-vinyl acetate copolymer (EVA) is widely used (for example, Patent Document 1). However, when a large number of solar cell modules using an EVA-based sealing material are connected in series, a leakage current is generated due to a potential difference from the aluminum frame arranged on the outer periphery of the module, and the PID phenomenon in which the output decreases is caused. May occur.

As an EVA type sealing material with improved PID resistance, for example, it contains EVA and a crosslinking agent, and the volume resistivity value in an atmosphere of 60 ° C. is 1.0 × 10 ^{13 to} 5.0 × 10 ¹⁴ Ω · cm. The sealing material for solar cell modules which is is proposed (patent document 2). However, the solar cell module sealing material is difficult to mold and difficult to manufacture. In addition, the solar cell module sealing material still has insufficient PID resistance in a high humidity environment. Particularly in a solar cell module in a high humidity environment, EVA as a sealing material is easily hydrolyzed to generate acetate ions. Therefore, the surface of the glass sealing material side that protects the light-receiving surface side of the module is eroded by the generated acetate ions, so that sodium ions are eluted to the sealing material side, and the performance of the solar battery cell is likely to deteriorate. .

  Moreover, in the solar cell module sealing material, it is important that the crosslinking proceeds sufficiently when the solar cells are sealed. When the crosslinking is insufficient, flow due to heat and poor adhesion occur, and the sealing reliability of the solar battery cell is lowered.

Japanese Patent No. 4751792 JP 2008-205448 A

  INDUSTRIAL APPLICABILITY The present invention uses a solar cell module sealing material that can obtain excellent PID resistance even in a high humidity environment and can seal solar cells with high reliability, and the solar cell module sealing material. An object of the present invention is to provide a solar cell module.

The present invention has the following configuration.
[1] An ethylene-vinyl acetate copolymer (A), tripropylene glycol diacrylate (B), and a functional group-containing silane compound (C), wherein the content of the tripropylene glycol diacrylate (B) is And 0.1 to 0.4 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer (A), and the content of the functional group-containing silane compound (C) is the ethylene-vinyl acetate. The sealing material for solar cell modules which is 0.05-0.15 mass part with respect to 100 mass parts of a copolymer (A).
[2] The solar cell module sealing material according to [1], which is a light receiving surface side sealing material.
[3] A solar battery cell and a pair of light receiving surface side sealing material and back surface sealing material sandwiching the solar battery cell, and any one of the light receiving surface side sealing material and the back surface side sealing material One or both are solar cell modules which consist of the sealing material for solar cell modules as described in [1].
[4] A solar battery cell and a pair of light-receiving surface side sealing material and back surface-side sealing material sandwiching the solar battery cell, wherein the light-receiving surface side sealing material is the solar battery according to [2]. A solar cell module comprising a module sealing material.

If the sealing material for solar cell modules of this invention is used, the outstanding PID resistance is obtained also in a high humidity environment, and a photovoltaic cell can be sealed with high reliability.
The solar cell module of the present invention is excellent in PID resistance even in a high humidity environment and has high reliability of sealing of solar cells.

It is sectional drawing which showed an example of the solar cell module of this invention.

[Encapsulant for solar cell module]
The sealing material for solar cell modules of the present invention (hereinafter also simply referred to as “sealing material”) is an ethylene-vinyl acetate copolymer (A) (hereinafter also referred to as “EVA (A)”). Tripropylene glycol diacrylate (B) (hereinafter also referred to as “compound (B)”) and a functional group-containing silane compound (C) (hereinafter also referred to as “compound (C)”).

  EVA (A) is a copolymer having a structural unit derived from ethylene and a structural unit derived from vinyl acetate (hereinafter referred to as “vinyl acetate unit”). 10-40 mass% is preferable and, as for the ratio of the vinyl acetate unit with respect to all the structural units in EVA, 15-30 mass% is more preferable.

The melt mass flow rate of EVA (A) (hereinafter referred to as “MFR”) is preferably 1 to 100 g / 10 minutes, and more preferably 2 to 50 g / 10 minutes. If the MFR of EVA (A) is not less than the lower limit value, the workability is excellent. If the MFR of EVA (A) is not more than the upper limit value, it is easy to ensure basic performance as a sealing material.
MFR (A) is a value measured under conditions of a temperature of 190 ° C. and a load of 21.18 N according to JIS K6924-2: 1997.

Density of EVA (A) is preferably from 0.930~0.970g / cm ^3, more preferably 0.940~0.960g / cm ^3. If the density of EVA (A) is equal to or higher than the lower limit value, the volume resistivity is increased, and the PID phenomenon in the solar cell module is easily suppressed. If the density of EVA (A) is not more than the upper limit value, the transparency and flexibility are more excellent.
The density of EVA (A) is a value measured according to JIS K 7112: 1999 (ISO 1183: 1987).

The melting point of EVA (A) is preferably 60 to 100 ° C, and more preferably 65 to 90 ° C. If the melting point of EVA (A) is at least the lower limit value, the volume resistivity is high. If the melting point of EVA (A) is not more than the upper limit value, the processability is excellent.
The melting point of EVA (A) is a value measured according to JIS K 7121: 2012 (ISO 3146).

The sealing material of this invention contains a compound (B) in addition to EVA (A).
Content of the compound (B) in the sealing material of this invention is 0.1-0.4 mass part with respect to 100 mass parts of EVA (A), and 0.2-0.4 mass part Is preferable, and 0.25 to 0.4 parts by mass is more preferable. If content of a compound (B) is more than a lower limit, the solar cell module which has the outstanding PID resistance also in a high humidity environment will be obtained. If content of a compound (B) is below an upper limit, bridge | crosslinking will fully advance, it can suppress that the flow and adhesion failure by a heat | fever are produced after sealing, and can seal a photovoltaic cell with high reliability.

As a functional group which a compound (C) has, a (meth) acryl group, a vinyl group, an epoxy group, an amino group etc. are mentioned, for example. Examples of the compound (C) include a silane coupling agent having a functional group. The (meth) acryl group means an acryl group or a methacryl group.
Specific examples of the compound (C) include, for example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy). ) Silane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3- Examples include aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, and 3-mercaptopropyltrimethoxysilane. Of these, 3-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, N-2- (amino) are preferred because of their good reactivity with resins and high hydrolysis resistance. Ethyl) -3-aminopropyltrimethoxysilane is preferred.
As a compound (C), 1 type may be used independently and 2 or more types may be used together.

  Content of the compound (C) in the sealing material of this invention is 0.05-0.15 mass part with respect to 100 mass parts of EVA (A), and 0.08-0.015 mass part. Is preferable, and 0.08-0.013 mass part is more preferable. If content of a compound (C) is more than a lower limit, sufficient adhesiveness will be acquired between a sealing material, a transparent protective layer, and a back sheet, and peeling can be suppressed also at the time of long-term outdoor exposure. If content of a compound (C) is below an upper limit, bridge | crosslinking by a compound (B) will fully advance, the outstanding PID resistance will be obtained, and a photovoltaic cell can be sealed with high reliability.

  The sealing material of the present invention may contain an additive in addition to EVA (A), compound (B) and compound (C). Examples of the additive include a crosslinking agent, a crosslinking assistant, an ultraviolet absorber, a light stabilizer, and an antioxidant. Especially, it is preferable that the sealing material of this invention contains a crosslinking agent. As an additive, 1 type may be used independently and 2 or more types may be used together.

A crosslinking agent is a component which bridge | crosslinks EVA (A). Examples of the crosslinking agent include known organic peroxides (peroxyketals, dialkyl peroxides, peroxyesters, etc.), photosensitizers and the like.
When the sealing material of this invention contains a crosslinking agent, 0.1-2.0 mass parts is preferable with respect to 100 mass parts of EVA (A), and content of the crosslinking agent in a sealing material is 0. 2 to 1.0 part by mass is more preferable.

The crosslinking aid is a compound having one or more polymerizable unsaturated groups (vinyl group, allyl group, (meth) acryloyl group, etc.), preferably two or more. Examples of the crosslinking aid include triallyl isocyanurate, triallyl cyanurate, and trimethylolpropane trimethacrylate.
When the sealing material of this invention contains a crosslinking adjuvant, 0-50 mass parts is preferable with respect to 100 mass parts of EVA (A), and, as for content of the crosslinking adjuvant in a sealing material, 0-2. Part by mass is more preferable.

Examples of the ultraviolet absorber include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and salicylic acid ester-based ultraviolet absorbers.
Examples of the light stabilizer include hindered amine light stabilizers.
Examples of the antioxidant include hindered phenol antioxidants and phosphite antioxidants.

  0.05-1.0 mm is preferable and, as for the thickness of the sealing material of this invention, 0.3-0.8 mm is more preferable. If the thickness of the sealing material is equal to or greater than the lower limit, it is easy to suppress cell cracking during module processing. If the thickness of the sealing material is not more than the upper limit value, the workability during processing is excellent.

  The total light transmittance of the sealing material of the present invention is preferably 80% or more, and more preferably 90% or more. In addition, the total light transmittance of the sealing material is a value measured according to JIS K 7105.

(Production method)
The manufacturing method of the sealing material of the present invention is not particularly limited. For example, EVA (A), compound (B), compound (C), and additives used as necessary are kneaded to obtain a resin composition. After obtaining, the method etc. of forming this resin composition into a sheet | seat are mentioned.

Examples of the kneading method include a method using an extruder, a ribbon blender, a plastograph, a kneader, a Banbury mixer, a calendar roll, and the like.
Examples of the sheet forming method include an extrusion molding method using a T die, a press molding method, and the like. Moreover, when making a resin composition into a solution, it can also be formed into a sheet by applying the resin composition to a release sheet and drying.

  In the sealing material of the present invention described above, the compound (B) is used in combination with EVA (A) at a specific ratio. Thereby, a solar cell module having excellent PID resistance even under high humidity conditions can be obtained. This is considered to be because the glycol structure of the compound (B) is taken into the crosslinked structure of the sealing material when the solar battery cell is sealed with the sealing material of the present invention. The glycol structure of compound (B) has the property of adsorbing sodium ions. As a result, even if EVA (A) is hydrolyzed under high humidity conditions to generate acetate ions, sodium ions are eluted from the glass surface, which is a transparent protective material, to the sealing material side. Sodium ions are adsorbed on the glycol structure of the compound (B) incorporated into the crosslinked structure. Therefore, it is thought that it becomes difficult for sodium ion to reach | attain to a photovoltaic cell, and the performance of a photovoltaic cell falls.

  Moreover, in the sealing material of this invention demonstrated above, the compound (C) is used together by the specific ratio to EVA (A). By using the compound (C), in the solar cell module, the adhesiveness between the sealing material and the transparent protective material or the back sheet becomes sufficient. Moreover, it can suppress that a radical is consumed excessively at the time of bridge | crosslinking and the whole crosslinking rate falls because a compound (C) is 0.15 mass part or less with respect to 100 mass parts of EVA (A). Thereby, the crosslinking by the compound (B) sufficiently proceeds to sufficiently obtain the above-described adsorption effect, and the solar cell can be sealed with high reliability because the flow and adhesion failure due to heat are suppressed.

  In the solar battery module, the sealing material of the present invention can adsorb the sodium ions even if sodium ions are eluted from the transparent protective material on the light receiving side to the sealing material side to suppress the performance deterioration of the solar battery cell. It is preferable to use it as a light receiving surface side sealing material.

[Solar cell module]
The solar cell module of this invention is equipped with the photovoltaic cell and a pair of light-receiving surface side sealing material and back surface side sealing material which clamped the said photovoltaic cell. In the solar cell module of the present invention, one or both of the pair of light-receiving surface side sealing material and the back surface side sealing material is the sealing material of the present invention. The solar cell module of this invention can employ | adopt a well-known aspect except using the sealing material of this invention as any one or both of a pair of light-receiving surface side sealing material and back surface side sealing material.

  Hereinafter, an example of the solar cell module of the present invention will be described and further described. The solar cell module 10 of the present embodiment includes a plurality of solar cells 11 and a pair of solar cell module sealing materials 12 (hereinafter referred to as “sealing material 12”) that are sealed with the solar cells 11 interposed therebetween. And a transparent protective material 13 and a back sheet 14 bonded together by the sealing material 12. In the solar cell module 10, the plurality of solar cells 11 are electrically connected in series via a tab string 15 having a conducting wire and a solder joint. Among the pair of sealing materials 12, the sealing material 12 on the transparent protective material 13 side is the light receiving surface side sealing material, and the sealing material 12 on the back sheet 14 side is the back surface side sealing material.

(Solar cell)
Examples of the solar battery cell 11 include a pn junction solar battery element having a structure in which a p-type semiconductor and an n-type semiconductor are joined. Examples of the pn junction type solar cell element include silicon (single crystal silicon, polycrystalline silicon, amorphous silicon, etc.), compound (GaAs, CIS, CdTe-CdS) and the like.

(Sealant for solar cell module)
In the present invention, either one or both of the light-receiving surface side sealing material and the back surface side sealing material is the sealing material of the present invention. In this example, at least one of the pair of sealing materials 12 is the sealing material of the present invention. In this invention, it is preferable that the light-receiving surface side sealing material in a solar cell module is the sealing material of this invention. Specifically, it is preferable that only the light receiving surface side sealing material is the sealing material of the present invention, or both the light receiving surface side sealing material and the back surface side sealing material are the sealing material of the present invention. In addition, only the back surface side sealing material may be the sealing material of the present invention.
When either one of the light-receiving surface side sealing material or the back surface side sealing material is the sealing material of the present invention, a known sealing material can be used as the other sealing material.

(Transparent protective material)
Examples of the transparent protective material 13 include a glass plate and a resin plate. As a glass plate, the template glass which gave the surface unevenness | corrugation from the point of light transmittance is preferable. As the material of the template glass, white plate glass (high transmission glass) with less iron content is preferable.

(Back sheet)
Examples of the material of the back sheet 14 include polyvinyl fluoride, polyester (polyethylene terephthalate, etc.), polyolefin (polyethylene, etc.), glass, metal (aluminum, etc.) and the like. The backsheet 14 may be a single layer or a multilayer.

(Method for manufacturing solar cell module)
It does not specifically limit as a manufacturing method of a solar cell module, For example, the following methods are mentioned. A plurality of photovoltaic cells 11 electrically connected using a tab string 15 are sandwiched between a pair of sealing materials 12, and a pair of sealing materials 12 are sandwiched between a transparent protective material 13 and a back sheet 14, To do. Next, the laminate is heated to bond the pair of sealing materials 12, the sealing material 12 and the transparent protective material 13, and the sealing material 12 and the back sheet 14.

  When the sealing material contains a crosslinking agent, the sealing material is heated to a temperature higher than the decomposition temperature of the crosslinking agent. When heated to a temperature equal to or higher than the decomposition temperature of the cross-linking agent, EVA contained in the encapsulant can be cross-linked, and the durability of the encapsulant can be further improved.

  In the solar cell module of the present invention described above, since the sealing material of the present invention is used, excellent PID resistance is expressed, and the sealing reliability of solar cells is also high.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by the following description.
[Formability]
The moldability in the molding of the sealing material in each example was evaluated. What was able to shape | mold the sealing material was set as "(circle) (passed)", and what was not able to form a sealing material and was not able to be obtained was set as "x (failed)."

[30 minutes reach torque (crosslinking degree measurement)]
A 20-mm square sample piece was cut out from the sealing material obtained in each example, and piled up so that the total mass became 5 g. Die vulcanization test A method (torsional vibration type flat plate die vulcanization test of JIS K 6300-2: 2001) The torque was measured for 30 minutes under the conditions of a test temperature: 150 ° C. and a torsional frequency: 100 ± 6 times / min. A 30-minute reaching torque of 0.37 N · m or more was regarded as acceptable.

[Output retention rate]
Using the sealing material obtained in each example, on the 200 mm square transparent glass, the single-crystal silicon cell in which the sealing material, the tab wire are wired, the sealing material, and the PET backsheet are laminated in this order, and 150 ° C. The test piece was thermocompression bonded for 30 minutes. A clip electrode was attached to the tab wire drawn from the test piece, and the initial output (Pmax) was measured using a solar simulator (Nisshinbo Mechatronics). Next, the tab wires of both electrodes are short-circuited, and a copper foil is attached to the entire glass surface. Then, electrodes are attached to the tab wires and the copper foil, and a DC voltage of 1000 V is applied in a thermostatic chamber at 85 ° C. and 85% humidity. Applied. After 96 hours in this state, the test piece was taken out from the thermostat and the copper foil was peeled off. Next, the output (P) after voltage marking was measured in the same manner as the initial output (Pmax), and the output retention rate was calculated by the following equation.
(Output retention rate) (%) = P / Pmax × 100
An output holding ratio of 70% or more was regarded as acceptable.

[material]
The raw materials used in this example are shown below.
(EVA (A))
A-1: EVA having a vinyl acetate unit content of 28% by mass.
(Compound (B))
TPGDA: tripropylene glycol diacrylate (product name “APG-200”, manufactured by Shin-Nakamura Chemical Co., Ltd.).
(Compound (X): comparison target)
HPGDA: heptapropylene glycol diacrylate (product name “APG-400”, manufactured by Shin-Nakamura Chemical Co., Ltd.).
NEGDA: Nonaethylene glycol diacrylate (product name “A-400”, manufactured by Shin-Nakamura Chemical Co., Ltd.).
(Compound (C))
C-1: 3-Methacryloxypropyltrimethoxysilane (silane coupling agent, product name “KBM-503”, manufactured by Shin-Etsu Chemical Co., Ltd.).
(Additive)
Cross-linking agent: t-butylperoxy-2-ethylhexyl monocarbonate (product name “Kayahexa AD”, manufactured by Kayaku Akzo).
Crosslinking aid: triallyl isocyanurate (product name “TAIC”, manufactured by Nippon Kasei Co., Ltd.).
Ultraviolet absorber: Benzophenone ultraviolet absorber (product name “CHIMASSORB 81”, manufactured by BASF Japan Ltd.).

[Example 1]
EVA (A-1) 100 parts by mass, compound (B-1) 0.3 parts by mass, compound (C-1) 0.12 parts by mass, crosslinking aid 0.5 parts by mass, and crosslinking aid 1.0 mass part and 0.3 mass part of ultraviolet absorbers were mixed, and the resin composition was obtained. The obtained resin composition was extruded using a T-die at a film forming temperature of 90 ° C. to obtain a sheet-like sealing material having a thickness of 0.45 mm.

[Comparative Examples 1-3]
A sheet-like sealing material was obtained in the same manner as in Example 1 except that the composition of the resin composition was changed as shown in Table 1.

[Comparative Example 4]
Except for changing the composition of the resin composition as shown in Table 1, when trying to obtain a sheet-like encapsulant in the same manner as in Example 1, bleeding occurred and film formation was impossible, and an encapsulant was obtained. I couldn't.

As shown in Table 1, in Example 1 where the compound (B) and the compound (C) are combined at a ratio defined in the present invention with respect to EVA (A), the output retention rate is high and the PID resistance is excellent. The torque reached for 30 minutes was high, and the crosslinking had progressed sufficiently.
On the other hand, in Comparative Example 1 in which the compound (B) was not used, the output retention rate was low and the PID resistance was inferior.
In Comparative Example 2 in which the content of the compound (B) was too large, the reaching torque was low for 30 minutes and the crosslinking did not proceed sufficiently.
In Comparative Example 3 using HPGDA instead of the compound (B), the output retention rate was low and the PID resistance was inferior.
In Comparative Example 4 using NEGDA instead of Compound (B), sufficient moldability was not obtained.

DESCRIPTION OF SYMBOLS 10 Solar cell module 11 Solar cell 12 Solar cell module sealing material 13 Transparent protective material 14 Back sheet

Claims (4)

An ethylene-vinyl acetate copolymer (A), tripropylene glycol diacrylate (B), and a functional group-containing silane compound (C);
Content of the said tripropylene glycol diacrylate (B) is 0.1-0.4 mass part with respect to 100 mass parts of the said ethylene-vinyl acetate copolymer (A),
The sealing for solar cell module, wherein the content of the functional group-containing silane compound (C) is 0.05 to 0.15 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer (A). Wood.   The sealing material for solar cell modules of Claim 1 which is a light-receiving surface side sealing material. Solar cells,
A pair of light receiving surface side sealing material and back side sealing material sandwiching the solar battery cell,
The solar cell module in which any one or both of the said light-receiving surface side sealing material and the said back surface side sealing material consist of the sealing material for solar cell modules of Claim 1. Solar cells,
A pair of light receiving surface side sealing material and back side sealing material sandwiching the solar battery cell,
The solar cell module in which the said light-receiving surface side sealing material consists of the sealing material for solar cell modules of Claim 2.

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