WO2013146629A1 - Solar cell sealing material sheet and solar cell module - Google Patents

Solar cell sealing material sheet and solar cell module Download PDF

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Publication number
WO2013146629A1
WO2013146629A1 PCT/JP2013/058477 JP2013058477W WO2013146629A1 WO 2013146629 A1 WO2013146629 A1 WO 2013146629A1 JP 2013058477 W JP2013058477 W JP 2013058477W WO 2013146629 A1 WO2013146629 A1 WO 2013146629A1
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WIPO (PCT)
Prior art keywords
solar cell
protrusion
sealing material
sheet
protrusions
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PCT/JP2013/058477
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French (fr)
Japanese (ja)
Inventor
小林祥之
中原誠
安藤隆
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東レ株式会社
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Application filed by 東レ株式会社 filed Critical 東レ株式会社
Priority to JP2013514428A priority Critical patent/JP6232627B2/en
Priority to KR1020147025999A priority patent/KR101559564B1/en
Priority to CN201380016918.9A priority patent/CN104272468B/en
Publication of WO2013146629A1 publication Critical patent/WO2013146629A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/048—Encapsulation of modules
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
    • B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
    • B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
    • B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
    • B32B17/10009—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the number, the constitution or treatment of glass sheets
    • B32B17/10018—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the number, the constitution or treatment of glass sheets comprising only one glass sheet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
    • B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
    • B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
    • B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
    • B32B17/1055—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the resin layer, i.e. interlayer
    • B32B17/10559—Shape of the cross-section
    • B32B17/10577—Surface roughness
    • B32B17/10587—Surface roughness created by embossing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
    • B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
    • B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
    • B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
    • B32B17/1055—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the resin layer, i.e. interlayer
    • B32B17/10788—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the resin layer, i.e. interlayer containing ethylene vinylacetate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2367/00—Polyesters, e.g. PET, i.e. polyethylene terephthalate
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the present invention relates to a solar cell encapsulant sheet and a solar cell module.
  • a solar cell module is manufactured by sealing a cell with a sealing material resin.
  • the glass is warped by heating from the hot plate in the laminating step, the temperature of the encapsulant becomes partially insufficient, and the solar battery cell is pressed against the unmelted encapsulant sheet to generate cracks. In some cases, this contributes to a decrease in module yield. In addition, air bubbles may remain between the sealing material sheet and the cell during lamination, which may deteriorate the appearance of the module.
  • embossing is performed in the manufacturing process of the sealing material sheet, a protrusion is formed on the sheet surface, and the cell is cracked by improving the cushioning property of the sheet (hereinafter referred to as cell crack). ) And measures to secure an air discharge route.
  • Patent Document 1 proposes a sealing material sheet in which a plurality of protrusions having a skirt portion having a cylindrical shape or a truncated cone shape as shown in FIG. 1 and a convex curved top portion are formed.
  • the present inventors have intensively studied to achieve the above object, and have found that the above problem can be solved by adopting the following configuration.
  • a solar cell encapsulant sheet made of a thermoplastic resin having 40 to 2300 protrusions per 1 cm 2 on at least one surface, the protrusions having a truncated pyramid shape with a polygonal bottom surface,
  • a solar cell encapsulant sheet comprising: a top portion having a convex curved surface shape, and a top portion ratio X defined below of the protrusion is 0.1 or more and 0.4 or less. Definition of the top ratio X: (1) P is the top of the protrusion, P ′ is the point at which the top P is projected onto the bottom of the truncated pyramid, and Q is the perpendicular foot drawn from P ′ to any side of the bottom of the truncated pyramid.
  • a cross section passing through the points (P, P ′, Q) is taken.
  • a section obtained by equally dividing the line segment P′Q by 10 is defined as sections R 1 to R 10 from the point Q, and a section R j on the line segment P′Q.
  • the straight lines that pass through the boundary points r j ⁇ 1 and r j of (1 ⁇ j ⁇ 10) and are orthogonal to the line segment P′Q are S j ⁇ 1 and S j, and the intersection of the straight line and the curve PQ is t j ⁇ 1 and t j .
  • an acute angle formed by the straight line connecting the points t j ⁇ 1 and t j and the straight line P′Q is ⁇ j .
  • the number of sections R j satisfying ( ⁇ 1 + ⁇ 2 ) / 2 ⁇ j ⁇ 4 ° (1 ⁇ j ⁇ 10) is obtained and divided by 10.
  • the above (1) to (3) are performed on each side of the bottom polygon, and the average is defined as the top ratio X of the protrusions.
  • the present invention it is possible to provide a high-quality solar cell sealing material sheet that suppresses uneven gloss while maintaining the cushioning property and degassing property of the sealing material sheet.
  • FIG. 3 is a partially enlarged view of a cross section including points (P, P ′, Q) of protrusions shown in FIG. 2. It is a schematic diagram of the other aspect of the surface protrusion part of the sealing material sheet of this invention.
  • the solar cell encapsulant sheet of the present invention is a solar cell encapsulant sheet made of a thermoplastic resin having 40 to 2300 protrusions per 1 cm 2 on at least one surface, and the protrusions are polygonal.
  • a solar cell encapsulating having a truncated pyramidal trapezoidal skirt and a convex curved top having a top ratio X defined as described later of the projection of 0.1 to 0.4 It is a material sheet.
  • thermoplastic resin used for the solar cell encapsulant sheet of the present invention is not particularly limited, but is a thermoplastic resin that is transparent and melts at a hot plate temperature (130 ° C. or higher and 160 ° C. or lower) during vacuum lamination.
  • a hot plate temperature 130 ° C. or higher and 160 ° C. or lower
  • EVA ethylene-vinyl acetate copolymer
  • ethylene-methyl methacrylate copolymer ethylene-ethyl acrylate copolymer
  • silane-modified polyethylene maleic acid-modified polyethylene
  • ionomer Polyvinyl butyral
  • the solar cell encapsulant sheet of the present invention is a multilayer sheet in which layers of different types of resin and additives and different amounts are laminated even if the type of resin and the type and amount of additive are uniform. May be.
  • the solar cell sealing material sheet of the invention has at least one of a 2300 or fewer projections 1 cm 2 per 40 or more on the surface. If the number of protrusions is less than 40 per cm 2 , cell cracks occur because the stress applied to each protrusion increases when the solar cell is pressed against an unmelted encapsulant sheet in the lamination process. It's easy to do. On the other hand, if the number of protrusions exceeds 2300 per 1 cm 2 , the individual protrusions become smaller, cushioning properties are reduced, cell cracks are likely to occur in the lamination process, degassing properties are also reduced, and bubbles are likely to remain. Become.
  • the protrusion on the surface of the solar cell encapsulant sheet of the present invention is composed of a truncated pyramidal skirt 11 having a polygonal bottom and a top 12 having a convex curved shape, as shown in FIGS. Is done.
  • the bottom shape of the truncated pyramid is preferably a triangle, a quadrangle, a pentagon, or a hexagon. If it is a heptagon or more polygon, it becomes a shape close to a curved surface and light reflection occurs, and uneven glossiness of the sheet may be recognized.
  • the solar cell encapsulant sheet of the present invention has a top portion ratio X defined below of 0.1 or more and 0. .4 or less, preferably 0.25 or more and 0.4 or less.
  • FIG. 3 shows a partially enlarged view of a cross section passing through the point (P, P ′, Q).
  • a section obtained by dividing the line segment P′Q into 10 equal parts is referred to as sections R 1 to R 10 from the point Q.
  • the top ratio X thus obtained is less than 0.1, the top of the projection becomes sharp, stress is concentrated on the tip of the projection in the laminating process, and cell cracks are likely to occur.
  • the top ratio X exceeds 0.4, the ratio of the curved surface portion becomes large and reflection occurs, so that uneven glossiness of the sealing material sheet can be seen.
  • the top ratio X is obtained with a valley formed between adjacent protrusions as a boundary.
  • the projection When the projection is viewed from above, if the topmost part P is biased near the contour of the projection, the projection collapses when the solar battery cell is pressed against the unmelted sealing material sheet, and the cushioning property is lowered.
  • the top is preferably near the center.
  • the shortest distance from the point P ′ at which the topmost part P is projected onto the bottom surface to the polygonal side of the bottom surface of the truncated pyramid is defined as L P ′, and the bottom surface when the shortest distance to the sides of the polygon and the L G of the center of L P '/ L G of the projection apex is preferably 0.5 or more and 1 or less. It is more preferred centrality L P '/ L G of the projection apex is 0.8 or more and 1 or less.
  • the solar cell encapsulant sheet of the present invention can form protrusions by pressing a mold engraved with a concave pattern on a heated sheet and then cooling.
  • the protrusions may be formed by batch processing using a metal mold made of a sheet metal plate engraved with a concave pattern, or a roll engraved with a concave pattern on the surface and an opposing roll.
  • the protrusions may be formed continuously by being sandwiched between them.
  • the aspect ratio H / D of the protrusion is 0.03 or more and 0.80 or less. preferable.
  • H / D is less than 0.03, cushioning properties obtained are small, and cell cracks may occur in the laminating process.
  • H / D exceeds 0.80, stress concentrates on the top of the protrusions, and cell cracks may occur in the lamination process.
  • the aspect ratio H / D of the protrusion is 0.03 or more and 0.30 or less, productivity is improved because the time required for forming the protrusion in the batch process is short while ensuring the minimum cushioning property. From the viewpoint, it is preferable, and from this viewpoint, 0.03 or more and less than 0.15 is more preferable. On the other hand, if it is 0.15 or more and 0.80 or less, since the cushioning property is better, it is preferable in that a wide range of conditions that can be processed without generation of cell cracks in the laminating step can be taken. 0.60 or less is more preferable.
  • top ratio X the center of L P '/ L G of the projection apex, while maintaining the cushioning property and deaeration by controlling the aspect ratio H / D of the protrusion, improve sheet quality suppressed gloss unevenness can do.
  • the thickness of the solar cell encapsulant sheet of the present invention can be set as appropriate, but the basis weight thickness (thickness when leveling the surface protrusions) is preferably 0.3 mm or more and 1 mm or less. If the fabric weight is less than 0.3 mm, the interconnector that is electrically connected to both the front and back surfaces of the cell cannot be embedded, and cell cracks may occur in the lamination process starting from the connector. May decrease.
  • Such a solar cell encapsulant sheet is cut into a cut sheet having a desired length and used for manufacturing a solar cell module.
  • the solar cell module of the present invention is disposed between the light-receiving surface protective material, the back surface protective material, and the light-receiving surface protective material and the back surface protective material, and the solar cells are sealed with the solar cell sealing material sheet.
  • Layer Such a solar cell module is manufactured using a light receiving surface protective material such as a glass plate or transparent plastic, a solar cell encapsulant sheet, solar cells, and a solar cell encapsulant similar to the solar cell encapsulant sheet.
  • a sheet and a back sheet such as a fluororesin or a polyester resin, or a back surface protection material such as glass are laminated in this order, and the melted solar cell is sealed by applying pressure or pressure while heating by a vacuum heating lamination method or the like. It can be manufactured by embedding solar cells in a fixing material sheet and integrally molding them.
  • the layer in which the solar battery cells are sealed with the solar battery sealing material sheet is preferably a layer in which the solar battery cells are sealed from both sides with the solar battery sealing material sheet thus obtained.
  • the sealing material sheet of the present invention is excellent in the cushioning property and deaeration property of the sealing material sheet to the solar battery cell when the above-structured materials are laminated and integrated, the solar battery cell and the solar battery sealing material Since the residual stress at the time of molding is small and no bubbles remain in the encapsulant, the solar cell module has excellent long-term durability.
  • the measurement method used in this example is shown below.
  • Projection height H Select five points evenly in the width direction from both ends of the encapsulant sheet and apply a laser from the direction perpendicular to the sheet surface using a shape measurement laser microscope VK-X100 (manufactured by Keyence Corporation). Three-dimensional shape information was obtained. From there, the distance from the top to the bottom of the protrusion was determined, and the average value of the five points was defined as the height H of the protrusion of the encapsulant sheet.
  • Diameter D of circumscribed circle on the bottom of the protrusion Obtain shape information of 5 points in the width direction by the same method as in (1), obtain the diameter of the circle circumscribing the bottom surface of the projection from there, determine the average value of the five points of the circumscribed circle of the bottom surface of the projection of the encapsulant sheet Diameter D.
  • Protrusion top ratio X The shape information of 5 points in the width direction was obtained by the same method as in (1), the top ratio X of the projections was obtained therefrom, and the average value of the five points was taken as the top ratio X of the projections of the encapsulant sheet.
  • Vacuum lamination was performed under the conditions of 1 minute, press 1 minute, and pressure holding 10 minutes (total 15 minutes).
  • stacking it laminated
  • Example 1 EVA resin (vinyl acetate content: 28% by mass, melt flow rate: 15 g / 10 min (190 ° C.)), crosslinking agent, crosslinking aid, silane coupling agent, ultraviolet absorber, light stabilization
  • the agent was supplied to a twin screw extruder, melted and kneaded, and extruded from a T die to obtain an EVA sheet having a thickness of 450 ⁇ m.
  • This EVA sheet and an aluminum plate engraved with a concave pattern are heated on a hot plate at 85 ° C., and after the sheet temperature reaches 85 ° C., it is pressed at a surface pressure of 5 MPa for 5 seconds, and then a water-cooled manual cooling press machine Was quenched by pressing at a surface pressure of 1 MPa for 1 minute to obtain a sealing material sheet having surface protrusions.
  • the bottom portion of the projection of the sealing material sheet is square, the top ratio X is 0.25, the center of L P '/ L G of the protruding apex 0.90, the aspect ratio H / D is 0.30, the number of protrusions is 900 pieces / cm 2 , there is no uneven gloss, and no cell cracks and bubbles are generated even when cells having a thickness of 200 ⁇ m and thickness of 180 ⁇ m are used in the production of a solar cell module. It was a good sheet that could not be made.
  • Examples 2 to 17 Same as Example 1 except that the shape of the hem of the sheet protrusion, the apex ratio X, the centrality of the apex L P ′ / L G , the aspect ratio H / D, and the aluminum plate engraving was changed to change the number of protrusions
  • the sealing material sheet was obtained by this method, and gloss unevenness, cell cracks, and deaeration were evaluated.
  • Examples 18 to 20 Change the sculpture of the aluminum plate to change the shape of the hem of the sheet protrusion, the top ratio X, the centrality L P ′ / L G of the top, the aspect ratio H / D, the number of protrusions, and press time 1, 2, Except for pressing for 3 seconds, a sealing material sheet was obtained in the same manner as in Example 17, and gloss unevenness, cell cracks, and deaeration were evaluated.

Abstract

The problem addressed by the present invention is providing an excellent quality solar cell sealing material sheet that suppresses variations in luster while maintaining the cushioning properties and degassing properties of the sealing material sheet. This solar cell sealing material sheet has 40 - 2300 protrusions per cm2 on at least one of the surfaces thereof and is formed from a thermoplastic resin. The solar cell sealing material sheet is characterized by the protrusions being constituted of a base part that has a pyramid frustum shape with a polygonal shape as the bottom surface and a top part that has a convex curved surface shape and by the top part proportion (X) of the protrusion being 0.1 - 0.4.

Description

太陽電池封止材シート、及び、太陽電池モジュールSolar cell encapsulant sheet and solar cell module
本発明は、太陽電池封止材シート及び太陽電池モジュールに関する。 The present invention relates to a solar cell encapsulant sheet and a solar cell module.
　近年、資源の有効利用やＣＯ２排出量削減の観点から、太陽光を直接電気エネルギーに変換する太陽電池が注目され、技術開発が進められている。 In recent years, from the viewpoint of effective use of resources and reduction of CO 2 emissions, solar cells that directly convert sunlight into electrical energy have attracted attention and technical development has been promoted.
　現在主流である結晶シリコン系太陽電池では、ガラス、封止材シート、太陽電池セル、封止材シート、バックシートをこの順に積層し、該積層体を真空・加熱条件下でラミネートし、溶融した封止材樹脂でセルを封止して太陽電池モジュールを製造している。 In crystalline silicon solar cells, which are currently mainstream, glass, encapsulant sheet, solar cell, encapsulant sheet, and back sheet are laminated in this order, and the laminate is laminated and melted under vacuum and heating conditions. A solar cell module is manufactured by sealing a cell with a sealing material resin.
　しかし、上記ラミネート工程において熱板からの加熱によりガラスが反り、封止材の昇温が部分的に不十分となり、太陽電池セルが未溶融状態の封止材シートに押し付けられてクラックが発生することがあり、これがモジュール収率を低下させる一因となっている。また、ラミネート時に封止材シートとセルの間に気泡が残留し、モジュールの外観を悪化させることがある。 However, the glass is warped by heating from the hot plate in the laminating step, the temperature of the encapsulant becomes partially insufficient, and the solar battery cell is pressed against the unmelted encapsulant sheet to generate cracks. In some cases, this contributes to a decrease in module yield. In addition, air bubbles may remain between the sealing material sheet and the cell during lamination, which may deteriorate the appearance of the module.
　上記トラブルを回避するため封止材シートの製造プロセスでエンボス加工を行い、シート表面に突起部を形成し、シートのクッション性を向上させることでセルにひびが入ること（以降、セルクラックと記す）を防止するとともに、空気の排出経路を確保する対策がとられている。 In order to avoid the above trouble, embossing is performed in the manufacturing process of the sealing material sheet, a protrusion is formed on the sheet surface, and the cell is cracked by improving the cushioning property of the sheet (hereinafter referred to as cell crack). ) And measures to secure an air discharge route.
　特許文献１では、図１に示すような円柱または円錐台形からなる裾部と凸な曲面形状の頂部を有する突起が複数形成された封止材シートが提案されている。 Patent Document 1 proposes a sealing material sheet in which a plurality of protrusions having a skirt portion having a cylindrical shape or a truncated cone shape as shown in FIG. 1 and a convex curved top portion are formed.
特開２０１０－２５８１２３号公報JP 2010-258123 A
　特許文献１に記載の技術では、突起によりクッション性や脱気性を向上できるが、その突起の形状に由来して周囲の光が突起に凸レンズのように映り込むため封止材シートに光沢ムラが発生し、シート品位を低下させるとともに、モジュール製造前に封止材シート中の異物、欠点を検査することが難しくなり、生産効率が低下するという問題があった。 In the technique described in Patent Document 1, cushioning and deaeration can be improved by the protrusion, but since the ambient light is reflected on the protrusion like a convex lens due to the shape of the protrusion, unevenness in gloss is generated on the sealing material sheet. In addition to reducing the sheet quality, it is difficult to inspect foreign matter and defects in the encapsulant sheet before manufacturing the module, resulting in reduced production efficiency.
　上記のような従来技術の問題点に鑑み、本発明では封止材シートのクッション性を維持しつつ光沢ムラを抑制できる太陽電池封止材シートを提供することにある。 In view of the above-described problems of the prior art, it is an object of the present invention to provide a solar cell encapsulant sheet that can suppress uneven gloss while maintaining the cushioning property of the encapsulant sheet.
　本発明者らは、上記目的を達成するため鋭意検討を行い、以下の構成を採ることで上記課題を解決できることを見出した。 The present inventors have intensively studied to achieve the above object, and have found that the above problem can be solved by adopting the following configuration.
　少なくとも一方の表面に、１ｃｍ２あたり４０個以上２３００個以下の突起を有する、熱可塑性樹脂からなる太陽電池封止材シートであって、前記突起は多角形を底面とする角錐台形の裾部と、凸な曲面形状である頂部とから構成され、該突起の以下に定義する頂部比率Ｘが０．１以上０．４以下であることを特徴とする太陽電池封止材シート。
頂部比率Ｘの定義：
（１）突起部の最頂部をＰ、前記最頂部Ｐを角錐台形の底面に投影した点をＰ’、Ｐ’から角錐台形の底面の任意の辺に引いた垂線の足をＱとし、これらの点（Ｐ，Ｐ’，Ｑ）を通る断面を取る。
（２）点（Ｐ，Ｐ’，Ｑ）を通る断面において、線分Ｐ’Ｑを１０等分した区間を点Ｑより区間Ｒ１～Ｒ１０とし、線分Ｐ’Ｑ上の区間Ｒｊ（１≦ｊ≦１０）の境界点ｒｊ－１、ｒｊを通り、線分Ｐ’Ｑに直交する直線をＳｊ－１、Ｓｊとし、該直線と曲線ＰＱの交点をｔｊ－１、ｔｊとする。区間Ｒｊにおいて、点ｔｊ－１、ｔｊを結ぶ直線と、直線Ｐ’Ｑのなす鋭角をθｊとする。
（３）（θ１＋θ２）／２　－θｊ≧４°（１≦ｊ≦１０）を満たす区間Ｒｊの数を求め、１０で除す。
（４）上記（１）～（３）を底面の多角形の各辺に対して行い、平均したものを、その突起の頂部比率Ｘと定義する。 A solar cell encapsulant sheet made of a thermoplastic resin having 40 to 2300 protrusions per 1 cm 2 on at least one surface, the protrusions having a truncated pyramid shape with a polygonal bottom surface, A solar cell encapsulant sheet comprising: a top portion having a convex curved surface shape, and a top portion ratio X defined below of the protrusion is 0.1 or more and 0.4 or less.
Definition of the top ratio X:
(1) P is the top of the protrusion, P ′ is the point at which the top P is projected onto the bottom of the truncated pyramid, and Q is the perpendicular foot drawn from P ′ to any side of the bottom of the truncated pyramid. A cross section passing through the points (P, P ′, Q) is taken.
(2) In a cross section passing through the point (P, P ′, Q), a section obtained by equally dividing the line segment P′Q by 10 is defined as sections R 1 to R 10 from the point Q, and a section R j on the line segment P′Q. The straight lines that pass through the boundary points r j−1 and r j of (1 ≦ j ≦ 10) and are orthogonal to the line segment P′Q are S j−1 and S j, and the intersection of the straight line and the curve PQ is t j− 1 and t j . In the section R j , an acute angle formed by the straight line connecting the points t j−1 and t j and the straight line P′Q is θ j .
(3) The number of sections R j satisfying (θ 1 + θ 2 ) / 2 −θ j ≧ 4 ° (1 ≦ j ≦ 10) is obtained and divided by 10.
(4) The above (1) to (3) are performed on each side of the bottom polygon, and the average is defined as the top ratio X of the protrusions.
　本発明によれば、封止材シートのクッション性や脱気性を維持しながら光沢ムラを抑制した品位の良い太陽電池封止材シートを提供できる。 According to the present invention, it is possible to provide a high-quality solar cell sealing material sheet that suppresses uneven gloss while maintaining the cushioning property and degassing property of the sealing material sheet.
従来の封止材シートの表面突起部の一例の概略断面図である。It is a schematic sectional drawing of an example of the surface protrusion part of the conventional sealing material sheet. 本発明の封止材シートの表面突起部の一例の概略模式図である。It is a schematic diagram of an example of the surface protrusion part of the sealing material sheet of this invention. 図２に示す突起の点（Ｐ、Ｐ’、Ｑ）を含む断面の部分拡大図である。FIG. 3 is a partially enlarged view of a cross section including points (P, P ′, Q) of protrusions shown in FIG. 2. 本発明の封止材シートの表面突起部の他の態様の概略模式図である。It is a schematic diagram of the other aspect of the surface protrusion part of the sealing material sheet of this invention.
　以下本発明の太陽電池封止材シートについて、説明する。 Hereinafter, the solar cell encapsulant sheet of the present invention will be described.
　本発明の太陽電池封止材シートは、少なくとも一方の表面に、１ｃｍ２あたり４０個以上２３００個以下の突起を有する熱可塑性樹脂からなる太陽電池封止材シートであって、前記突起は多角形を底面とする角錐台形の裾部と、凸な曲面形状である頂部とから構成され、該突起の後述のように定義する頂部比率Ｘが０．１以上０．４以下である太陽電池封止材シートである。 The solar cell encapsulant sheet of the present invention is a solar cell encapsulant sheet made of a thermoplastic resin having 40 to 2300 protrusions per 1 cm 2 on at least one surface, and the protrusions are polygonal. A solar cell encapsulating having a truncated pyramidal trapezoidal skirt and a convex curved top having a top ratio X defined as described later of the projection of 0.1 to 0.4 It is a material sheet.
　本発明の太陽電池封止材シートに用いられる熱可塑性樹脂は、特に限定されないが、透明性があり、真空ラミネート時の熱板温度（１３０℃以上１６０℃以下）で溶融する熱可塑性樹脂であることが好ましく、例えば、ポリエチレン、エチレン－酢酸ビニル共重合体（以下「ＥＶＡ」と記載）、エチレン－メチルメタクリレート共重合体、エチレン－エチルアクリレート共重合体、シラン変性ポリエチレン、マレイン酸変性ポリエチレン、アイオノマー、ポリビニルブチラールなどが好ましく用いられる。また、封止特性向上のために必要に応じて架橋剤、架橋助剤、カップリング剤、紫外線吸収剤、光安定化剤などの添加剤を適宜使用してもよい。また、本発明の太陽電池封止材シートは樹脂の種類や添加剤の種類や量が均一な単層シートでも、樹脂の種類や添加剤の種類や量が異なる層を積層した多層シートであっても良い。 The thermoplastic resin used for the solar cell encapsulant sheet of the present invention is not particularly limited, but is a thermoplastic resin that is transparent and melts at a hot plate temperature (130 ° C. or higher and 160 ° C. or lower) during vacuum lamination. For example, polyethylene, ethylene-vinyl acetate copolymer (hereinafter referred to as “EVA”), ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, silane-modified polyethylene, maleic acid-modified polyethylene, ionomer Polyvinyl butyral is preferably used. Moreover, you may use suitably additives, such as a crosslinking agent, a crosslinking adjuvant, a coupling agent, a ultraviolet absorber, a light stabilizer, as needed for a sealing characteristic improvement. Further, the solar cell encapsulant sheet of the present invention is a multilayer sheet in which layers of different types of resin and additives and different amounts are laminated even if the type of resin and the type and amount of additive are uniform. May be.
　そして、本発明の太陽電池封止材シートには少なくとも一方の表面に１ｃｍ２あたり４０個以上２３００個以下の突起を有する。突起の個数が１ｃｍ２あたり４０個未満であると、ラミネート工程において太陽電池セルが未溶融状態の封止材シートに押し付けられた時、個々の突起に掛かる応力が高くなるため、セルクラックが発生しやすい。一方、突起の個数が１ｃｍ２あたり２３００個を越えると、個々の突起が小さくなるためクッション性が低下し、ラミネート工程でのセルクラックが発生しやすく、脱気性も低下し、気泡が残留しやすくなる。 Then, the solar cell sealing material sheet of the invention has at least one of a 2300 or fewer projections 1 cm 2 per 40 or more on the surface. If the number of protrusions is less than 40 per cm 2 , cell cracks occur because the stress applied to each protrusion increases when the solar cell is pressed against an unmelted encapsulant sheet in the lamination process. It's easy to do. On the other hand, if the number of protrusions exceeds 2300 per 1 cm 2 , the individual protrusions become smaller, cushioning properties are reduced, cell cracks are likely to occur in the lamination process, degassing properties are also reduced, and bubbles are likely to remain. Become.
　本発明の太陽電池封止材シートの表面にある突起は、図２や図４に示す通り、多角形を底面とする角錐台形の裾部１１と、凸な曲面形状である頂部１２とから構成される。裾部を角錐台形とすることで曲面部を減少させ、周囲の光の映り込みを防止し、シートの光沢ムラを抑制できる。前記角錐台形の底面形状は三角形、四角形、五角形、または六角形であることが好ましい。七角形以上の多角形となると曲面と近い形状になり光の映り込みが起こり、シートの光沢ムラが認められる場合がある。 The protrusion on the surface of the solar cell encapsulant sheet of the present invention is composed of a truncated pyramidal skirt 11 having a polygonal bottom and a top 12 having a convex curved shape, as shown in FIGS. Is done. By making the skirt part a truncated pyramid, the curved surface part can be reduced, the reflection of ambient light can be prevented, and uneven glossiness of the sheet can be suppressed. The bottom shape of the truncated pyramid is preferably a triangle, a quadrangle, a pentagon, or a hexagon. If it is a heptagon or more polygon, it becomes a shape close to a curved surface and light reflection occurs, and uneven glossiness of the sheet may be recognized.
　また、映り込み防止のためには凸な曲面形状の頂部１２の比率が低いことが重要であり、本発明の太陽電池封止材シートは、以下に定義する頂部比率Ｘが０．１以上０．４以下であり、０．２５以上０．４以下であれば好ましい。 Moreover, it is important that the ratio of the convex curved top portions 12 is low in order to prevent reflection, and the solar cell encapsulant sheet of the present invention has a top portion ratio X defined below of 0.1 or more and 0. .4 or less, preferably 0.25 or more and 0.4 or less.
　頂部比率Ｘの求め方について、図２の四角錐台形を裾部に有する突起２を例に用いて具体的に説明する。突起部の最頂部をＰ、前記最頂部Ｐを角錐台形の底面１０に投影した点をＰ’とし、Ｐ’から四角形の任意の一辺に引いた垂線の足をＱとする。点（Ｐ，Ｐ’，Ｑ）を通る断面の部分拡大図を図３に示す。線分Ｐ’Ｑを１０等分した区間を、点Ｑより区間Ｒ１～Ｒ１０と呼ぶ。線分Ｐ’Ｑ上のある区間Ｒｊ（１≦ｊ≦１０）について、線分Ｐ’Ｑ上の境界点ｒｊ－１、ｒｊを通り、線分Ｐ’Ｑに直交する直線をＳｊ－１、Ｓｊとし、該直線と曲線ＰＱの交点をｔｊ－１、ｔｊとする。区間Ｒｊにおいて、点ｔｊ－１、ｔｊを結ぶ直線と、直線Ｐ’Ｑのなす鋭角をθｊとした時、｛（θ１＋θ２）／２｝－θｊ≧４°（１≦ｊ≦１０）を満たす区間Ｒｊの数を求め、それを１０で除す。本計算を底面の四角形の各辺に対して行い、平均した数値をその突起の頂部比率Ｘと定義する。ここでは角錐台形の底面の形状が、四角形の場合について説明したが、それ以外の場合についても、各辺に対して行う他は変わりはない。 The method for obtaining the top ratio X will be specifically described with reference to an example of the protrusion 2 having a square pyramid trapezoidal shape in FIG. Let P be the top of the protrusion, P ′ be the point at which the top P is projected onto the bottom surface 10 of the truncated pyramid, and Q be the foot of the perpendicular drawn from P ′ to any one side of the square. FIG. 3 shows a partially enlarged view of a cross section passing through the point (P, P ′, Q). A section obtained by dividing the line segment P′Q into 10 equal parts is referred to as sections R 1 to R 10 from the point Q. For a certain section R j (1 ≦ j ≦ 10) on the line segment P′Q, a straight line passing through the boundary points r j−1 and r j on the line segment P′Q and orthogonal to the line segment P′Q is represented by S Let j−1 and S j be the intersections of the straight line and the curve PQ, and let t j−1 and t j be the intersection. In the section R j , when θ j is an acute angle formed between the straight line connecting the points t j−1 and t j and the straight line P′Q, {(θ 1 + θ 2 ) / 2} −θ j ≧ 4 ° (1 Determine the number of intervals R j that satisfy ≦ j ≦ 10) and divide it by 10. This calculation is performed for each side of the bottom square, and the averaged value is defined as the top ratio X of the protrusion. Here, the case where the shape of the bottom surface of the truncated pyramid is a quadrangle has been described. However, in other cases, there is no change except that it is performed for each side.
　このようにして求めた頂部比率Ｘが０．１未満であると、突起の頂部が鋭くなり、ラミネート工程で突起先端部に応力が集中しセルクラックが発生しやすい。一方、頂部比率Ｘが０．４を越えると、曲面部の比率が大きくなり映り込みが起こるため、封止材シートの光沢ムラが見られるようになる。 When the top ratio X thus obtained is less than 0.1, the top of the projection becomes sharp, stress is concentrated on the tip of the projection in the laminating process, and cell cracks are likely to occur. On the other hand, when the top ratio X exceeds 0.4, the ratio of the curved surface portion becomes large and reflection occurs, so that uneven glossiness of the sealing material sheet can be seen.
　なお、複数の突起が相互に重なっており底面の定義が難しい場合は、隣り合う突起との間に作られる谷を境目として頂部比率Ｘを求めることとする。 In addition, when a plurality of protrusions overlap with each other and it is difficult to define the bottom surface, the top ratio X is obtained with a valley formed between adjacent protrusions as a boundary.
　突起を上から見た時に最頂部Ｐが突起の輪郭付近に偏っていると、太陽電池セルが未溶融の封止材シートに押し付けられた時に突起が倒れてクッション性が低下するので、突起の頂部は中心付近にあることが好ましい。図２に示す通り、最頂部Ｐを底面に投影した点Ｐ’から角錐台形の底面の多角形の辺までの最短距離をＬＰ’とし、角錐台形の底面の多角形の重心Ｇから前記底面の多角形の辺までの最短距離をＬＧとした時、突起頂部の中心度ＬＰ’／ＬＧは０．５以上１以下であることが好ましい。より好ましくは突起頂部の中心度ＬＰ’／ＬＧは０．８以上１以下であることが好ましい。 When the projection is viewed from above, if the topmost part P is biased near the contour of the projection, the projection collapses when the solar battery cell is pressed against the unmelted sealing material sheet, and the cushioning property is lowered. The top is preferably near the center. As shown in FIG. 2, the shortest distance from the point P ′ at which the topmost part P is projected onto the bottom surface to the polygonal side of the bottom surface of the truncated pyramid is defined as L P ′, and the bottom surface when the shortest distance to the sides of the polygon and the L G of the center of L P '/ L G of the projection apex is preferably 0.5 or more and 1 or less. It is more preferred centrality L P '/ L G of the projection apex is 0.8 or more and 1 or less.
　本発明の太陽電池封止材シートは、加熱したシートに凹型の模様が彫刻された金型を押し付けて、その後冷却することで突起を形成することができる。その場合、凹型の模様が彫刻された枚葉の金属板からなる金型を用いバッチ処理で突起を形成してもよく、あるいは表面に凹型の模様が彫刻されたロールと、対向のロールとを用い、間に挟み込んで連続式で突起を形成しても良い。 The solar cell encapsulant sheet of the present invention can form protrusions by pressing a mold engraved with a concave pattern on a heated sheet and then cooling. In that case, the protrusions may be formed by batch processing using a metal mold made of a sheet metal plate engraved with a concave pattern, or a roll engraved with a concave pattern on the surface and an opposing roll. Alternatively, the protrusions may be formed continuously by being sandwiched between them.
　突起のＰＰ’間の長さを突起の高さＨとし、突起の底面の外接円の直径をＤとしたとき、突起のアスペクト比Ｈ／Ｄが０．０３以上０．８０以下であることが好ましい。Ｈ／Ｄが０．０３未満であると得られるクッション性が小さく、ラミネート工程でのセルクラックが発生する場合がある。一方、Ｈ／Ｄが０．８０を越えると、突起の頂部に応力が集中するため、ラミネート工程でセルクラックが発生することがある。また、突起のアスペクト比Ｈ／Ｄが０．０３以上０．３０以下であれば、最低限必要なクッション性を確保しつつバッチ処理での突起の形成に必要な時間が短いために生産性が良い点で好ましく、かかる観点からは０．０３以上０．１５未満がより好ましい。一方０．１５以上０．８０以下であれば、クッション性がより良いために、ラミネート工程でセルクラックの発生なく加工できる条件範囲を広く採ることができる点で好ましく、かかる観点から０．２０以上０．６０以下がより好ましい。 When the length between the protrusions PP ′ is the height H of the protrusion and the diameter of the circumscribed circle on the bottom surface of the protrusion is D, the aspect ratio H / D of the protrusion is 0.03 or more and 0.80 or less. preferable. When the H / D is less than 0.03, cushioning properties obtained are small, and cell cracks may occur in the laminating process. On the other hand, if H / D exceeds 0.80, stress concentrates on the top of the protrusions, and cell cracks may occur in the lamination process. Further, when the aspect ratio H / D of the protrusion is 0.03 or more and 0.30 or less, productivity is improved because the time required for forming the protrusion in the batch process is short while ensuring the minimum cushioning property. From the viewpoint, it is preferable, and from this viewpoint, 0.03 or more and less than 0.15 is more preferable. On the other hand, if it is 0.15 or more and 0.80 or less, since the cushioning property is better, it is preferable in that a wide range of conditions that can be processed without generation of cell cracks in the laminating step can be taken. 0.60 or less is more preferable.
　このように頂部比率Ｘ、突起頂部の中心度ＬＰ’／ＬＧ、突起のアスペクト比Ｈ／Ｄを制御することでクッション性や脱気性を維持しつつ、光沢ムラを抑制しシート品位を向上することができる。 Thus top ratio X, the center of L P '/ L G of the projection apex, while maintaining the cushioning property and deaeration by controlling the aspect ratio H / D of the protrusion, improve sheet quality suppressed gloss unevenness can do.
　本発明の太陽電池封止材シートの厚みは、適宜設定することができるが、目付厚み（表面突起をならした時の厚み）が０．３ｍｍ以上１ｍｍ以下であることが好ましい。目付厚みが０．３ｍｍ未満ではセルの表裏両面に電気的に接続するインターコネクタを包埋できず、コネクタを起点としてラミネート工程でセルクラックが発生する場合があり、１ｍｍよりも厚いと透明性が低下する場合がある。 The thickness of the solar cell encapsulant sheet of the present invention can be set as appropriate, but the basis weight thickness (thickness when leveling the surface protrusions) is preferably 0.3 mm or more and 1 mm or less. If the fabric weight is less than 0.3 mm, the interconnector that is electrically connected to both the front and back surfaces of the cell cannot be embedded, and cell cracks may occur in the lamination process starting from the connector. May decrease.
　このような太陽電池封止材シートは、所望長さのカットシートに裁断され、太陽電池モジュールの製造に用いられる。本発明の太陽電池モジュールは、受光面保護材と、裏面保護材と、この受光面保護材と裏面保護材との間に配置され、太陽電池封止材シートにより太陽電池セルが封止された層と、で構成されている。かかる太陽電池モジュールの製造は、ガラス板や透明なプラスチック等の受光面保護材と、太陽電池封止材シートと、太陽電池セルと、前記太陽電池封止材シートと同様の太陽電池封止材シートと、フッ素樹脂やポリエステル樹脂等のバックシートやガラス等の裏面保護材とをこの順に積層し、これらを真空加熱ラミネート法等により加熱しながら減圧や加圧することで、溶融させた太陽電池封止材シート中に太陽電池セルを包埋させて一体成形することにより製造することができる。太陽電池封止材シートにより太陽電池セルが封止された層としては、このようにして得られる太陽電池封止材シートにより太陽電池セルが両面から封止された層であることが好ましい。 Such a solar cell encapsulant sheet is cut into a cut sheet having a desired length and used for manufacturing a solar cell module. The solar cell module of the present invention is disposed between the light-receiving surface protective material, the back surface protective material, and the light-receiving surface protective material and the back surface protective material, and the solar cells are sealed with the solar cell sealing material sheet. Layer. Such a solar cell module is manufactured using a light receiving surface protective material such as a glass plate or transparent plastic, a solar cell encapsulant sheet, solar cells, and a solar cell encapsulant similar to the solar cell encapsulant sheet. A sheet and a back sheet such as a fluororesin or a polyester resin, or a back surface protection material such as glass are laminated in this order, and the melted solar cell is sealed by applying pressure or pressure while heating by a vacuum heating lamination method or the like. It can be manufactured by embedding solar cells in a fixing material sheet and integrally molding them. The layer in which the solar battery cells are sealed with the solar battery sealing material sheet is preferably a layer in which the solar battery cells are sealed from both sides with the solar battery sealing material sheet thus obtained.
　本発明の封止材シートは、上記構成の材料を積層一体化するときの太陽電池セルへの封止材シートのクッション性や脱気性に優れることから太陽電池セルと太陽電池封止材との間の成形時の残留応力が小さく、また、封止材中の気泡の残存もないことから、長期にわたる耐久性が優れた太陽電池モジュールとなる。 Since the sealing material sheet of the present invention is excellent in the cushioning property and deaeration property of the sealing material sheet to the solar battery cell when the above-structured materials are laminated and integrated, the solar battery cell and the solar battery sealing material Since the residual stress at the time of molding is small and no bubbles remain in the encapsulant, the solar cell module has excellent long-term durability.
　本発明を以下の実施例により更に詳しく説明するが、本発明は以下の実施例により何ら限定されるものではない。 The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.
　本実施例で用いた測定法を下記に示す。 The measurement method used in this example is shown below.
　（１）突起の高さＨ
　封止材シートの両端から幅方向に均等に５点選び、形状測定レーザーマイクロスコープＶＫ－Ｘ１００（キーエンス社製）を用い、シート面に垂直な方向からレーザーを当て、シートに形成された突起の３次元的な形状情報を得た。そこから突起の最頂部から底面までの距離を求め、５点の平均値を封止材シートの突起の高さＨとした。 (1) Projection height H
Select five points evenly in the width direction from both ends of the encapsulant sheet and apply a laser from the direction perpendicular to the sheet surface using a shape measurement laser microscope VK-X100 (manufactured by Keyence Corporation). Three-dimensional shape information was obtained. From there, the distance from the top to the bottom of the protrusion was determined, and the average value of the five points was defined as the height H of the protrusion of the encapsulant sheet.
　（２）突起の底面の外接円の直径Ｄ
　（１）と同様の方法により幅方向５点の形状情報を得、そこから突起の底面に外接する円の直径を求め、５点の平均値を封止材シートの突起の底面の外接円の直径Ｄとした。 (2) Diameter D of circumscribed circle on the bottom of the protrusion
Obtain shape information of 5 points in the width direction by the same method as in (1), obtain the diameter of the circle circumscribing the bottom surface of the projection from there, determine the average value of the five points of the circumscribed circle of the bottom surface of the projection of the encapsulant sheet Diameter D.
　（３）突起の頂部比率Ｘ
　（１）と同様の方法により幅方向５点の形状情報を得、そこから突起の頂部比率Ｘを求め、５点の平均値を封止材シートの突起の頂部比率Ｘとした。 (3) Protrusion top ratio X
The shape information of 5 points in the width direction was obtained by the same method as in (1), the top ratio X of the projections was obtained therefrom, and the average value of the five points was taken as the top ratio X of the projections of the encapsulant sheet.
　（４）突起頂部の中心度ＬＰ’／ＬＧ
　（１）と同様の方法により幅方向５点の形状情報を得、そこから突起頂部の中心度ＬＰ’／ＬＧを求め、５点の平均値を封止材シートの突起頂部の中心度ＬＰ’／ＬＧとした。 (4) the center of L P of the protruding apex '/ L G
(1) to obtain the shape information of the width direction 5 points in the same manner as, from which obtains a center level L P '/ L G of the projection top, center of the protruding top of the encapsulant sheet the average of 5 points It was L P '/ L G.
　（５）光沢ムラの判定
　封止材シートの光沢を目視にて確認し、光沢ムラがない状態を「Ａ」、異物・欠点の検出には問題の無い程度の軽微な光沢ムラを「Ｂ」、顕著な光沢ムラを「Ｃ」として３段階で評価した。 (5) Judgment of gloss unevenness The gloss of the encapsulant sheet is visually confirmed, “A” when there is no gloss unevenness, and “B” with a slight gloss unevenness that does not cause any problems in detecting foreign matter and defects. The remarkable gloss unevenness was evaluated as “C” in three stages.
　（６）セルクラックの判定
　１８０ｍｍ角の正方形状の封止材シート、ガラス板（厚み３ｍｍ）と、ポリエステル製太陽電池バックシート（厚み２４０μｍ）を用意した。二種類の多結晶太陽電池セル（３バスバー、サイズ１５６ｍｍ角、厚み２００μｍ、並びに３バスバー、サイズ１５６ｍｍ角、厚み１８０μｍ）に、自動配線機を使用してインターコネクタ（厚み２８０μｍ、幅２ｍｍ）を半田付けし、インターコネクタ付きの太陽電池セルを作成した。前記のガラス板の上に、封止材シート、インターコネクタ付き太陽電池セル、封止材シート、バックシートの順で積層し、ＪＥＴ社製真空ラミネーターにて、熱板温度１４５℃、真空引き４分、プレス１分、圧力保持１０分（合計１５分）の条件で真空ラミネートを行った。なお、前記の積層においては封止材シートの突起が太陽電池セルに接するように積層した。得られた太陽電池モジュールのセルクラックを目視およびＥＬ画像検査装置にて確認し、厚み２００μｍ、ならびに厚み１８０μｍのセルを使用した太陽電池モジュールにおいて、ＥＬ画像検査にてクラック由来の非発光部が無い状態を「ＡＡ」、厚み２００μｍのセルを使用した太陽電池モジュールにおいて、ＥＬ画像検査にてクラック由来の非発光部が無いが、厚み１８０μｍのセルを使用した太陽電池モジュールにおいて、目視では確認できないがＥＬ画像検査ではクラック由来の非発光部がある状態を「Ａ」、厚み２００μｍのセルを使用した太陽電池モジュールにおいて目視では確認できないがＥＬ画像検査ではクラック由来の非発光部がある状態を「Ｂ」、厚み２００μｍのセルを使用した太陽電池モジュールにおいて目視で確認できるセルクラックがある状態を「Ｃ」として、４段階で評価した。 (6) Determination of cell crack A 180 mm square sealing material sheet, a glass plate (thickness 3 mm), and a polyester solar battery backsheet (thickness 240 μm) were prepared. Solder the interconnector (thickness 280 μm, width 2 mm) to two types of polycrystalline solar cells (3 busbars, size 156 mm square, thickness 200 μm, and 3 bus bars, size 156 mm square, thickness 180 μm) using an automatic wiring machine A solar cell with an interconnector was created. On the glass plate, a sealing material sheet, a solar battery cell with an interconnector, a sealing material sheet, and a back sheet are laminated in this order, and a hot plate temperature of 145 ° C. and a vacuum drawing of 4 using a JET vacuum laminator. Vacuum lamination was performed under the conditions of 1 minute, press 1 minute, and pressure holding 10 minutes (total 15 minutes). In addition, in the said lamination | stacking, it laminated | stacked so that the processus | protrusion of a sealing material sheet might contact | connect a photovoltaic cell. Cell cracks of the obtained solar cell module were confirmed visually and with an EL image inspection apparatus, and in a solar cell module using cells having a thickness of 200 μm and a thickness of 180 μm, there was no non-light emitting portion derived from cracks in EL image inspection In the solar cell module using a cell having a thickness of “AA” and a thickness of 200 μm, there is no non-light-emitting portion derived from cracks in EL image inspection, but in a solar cell module using a cell having a thickness of 180 μm, it cannot be visually confirmed. In EL image inspection, a state where there is a non-light emitting portion derived from a crack is “A”, and in a solar cell module using a cell having a thickness of 200 μm, it cannot be visually confirmed. "In a solar cell module using cells with a thickness of 200 µm, That a state in which there is a cell crack as "C", was evaluated in four stages.
　（７）脱気性の評価
　上記（６）にて得られた太陽電池モジュール中に気泡が残存しているかを目視にて確認し、気泡がない状態を「Ａ」、気泡が確認できる状態を「Ｃ」として、２段階で評価した。 (7) Evaluation of deaeration The presence of bubbles in the solar cell module obtained in (6) above is visually confirmed. The state where there are no bubbles is “A”, and the state where bubbles can be confirmed is “ C ”was evaluated in two stages.
　（実施例１）ＥＶＡ樹脂（酢酸ビニル含有量：２８質量％、メルトフローレイト：１５ｇ／１０分（１９０℃））、架橋剤、架橋助剤、シランカップリング剤、紫外線吸収剤、光安定化剤を２軸押出機に供給して溶融混練し、Ｔダイから押出して厚み４５０μｍのＥＶＡシートを得た。このＥＶＡシートと凹型の模様が彫刻されたアルミ板を８５℃の熱板上で加熱し、シート温度が８５℃に到達した後、面圧５ＭＰａにて５秒間プレスした後水冷式手動冷却プレス機にて面圧１ＭＰａにて１分間プレスすることで急冷し、表面突起を有する封止材シートを得た。 (Example 1) EVA resin (vinyl acetate content: 28% by mass, melt flow rate: 15 g / 10 min (190 ° C.)), crosslinking agent, crosslinking aid, silane coupling agent, ultraviolet absorber, light stabilization The agent was supplied to a twin screw extruder, melted and kneaded, and extruded from a T die to obtain an EVA sheet having a thickness of 450 μm. This EVA sheet and an aluminum plate engraved with a concave pattern are heated on a hot plate at 85 ° C., and after the sheet temperature reaches 85 ° C., it is pressed at a surface pressure of 5 MPa for 5 seconds, and then a water-cooled manual cooling press machine Was quenched by pressing at a surface pressure of 1 MPa for 1 minute to obtain a sealing material sheet having surface protrusions.
　表１に示す通り、この封止材シートの突起の底部は四角形であり、頂部比率Ｘは０．２５、突起頂部の中心度ＬＰ’／ＬＧは０．９０、アスペクト比Ｈ／Ｄは０．３０、突起の個数は９００個／ｃｍ２であり、光沢ムラがなく、太陽電池モジュールの作成に際し、厚み２００μｍ並びに厚み１８０μｍのセルを用いても、セルクラックが発生せず、気泡も発生させない良好なシートであった。 As shown in Table 1, the bottom portion of the projection of the sealing material sheet is square, the top ratio X is 0.25, the center of L P '/ L G of the protruding apex 0.90, the aspect ratio H / D is 0.30, the number of protrusions is 900 pieces / cm 2 , there is no uneven gloss, and no cell cracks and bubbles are generated even when cells having a thickness of 200 μm and thickness of 180 μm are used in the production of a solar cell module. It was a good sheet that could not be made.
　（実施例２～１７）
　シート突起の裾部の形状、頂部比率Ｘ、頂部の中心度ＬＰ’／ＬＧ、アスペクト比Ｈ／Ｄ、突起の個数を変えるようにアルミ板の彫刻を変更した以外は実施例１と同様の方法で封止材シートを得て、光沢ムラ、セルクラック、脱気性を評価した。 (Examples 2 to 17)
Same as Example 1 except that the shape of the hem of the sheet protrusion, the apex ratio X, the centrality of the apex L P ′ / L G , the aspect ratio H / D, and the aluminum plate engraving was changed to change the number of protrusions The sealing material sheet was obtained by this method, and gloss unevenness, cell cracks, and deaeration were evaluated.
　（実施例１８～２０）
　シート突起の裾部の形状、頂部比率Ｘ、頂部の中心度ＬＰ’／ＬＧ、アスペクト比Ｈ／Ｄ、突起の個数を変えるようにアルミ板の彫刻を変更しプレス時間を１、２、３秒間と変えてプレスした以外は実施例１７と同様の方法で封止材シートを得て、光沢ムラ、セルクラック、脱気性を評価した。 (Examples 18 to 20)
Change the sculpture of the aluminum plate to change the shape of the hem of the sheet protrusion, the top ratio X, the centrality L P ′ / L G of the top, the aspect ratio H / D, the number of protrusions, and press time 1, 2, Except for pressing for 3 seconds, a sealing material sheet was obtained in the same manner as in Example 17, and gloss unevenness, cell cracks, and deaeration were evaluated.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　（比較例１～６）
　シート突起の裾部の形状、頂部比率Ｘ、頂部の中心度ＬＰ’／ＬＧ、アスペクト比Ｈ／Ｄ、突起の個数を変えるようにアルミ板の彫刻を変更した以外は実施例１と同様の方法で封止材シートを得て、光沢ムラ、セルクラック、脱気性を評価した。 (Comparative Examples 1 to 6)
Same as Example 1 except that the shape of the hem of the sheet protrusion, the apex ratio X, the centrality of the apex L P ′ / L G , the aspect ratio H / D, and the aluminum plate engraving was changed to change the number of protrusions The sealing material sheet was obtained by this method, and gloss unevenness, cell cracks, and deaeration were evaluated.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　　１　　円錐台形を裾部に有する突起
　　２　　四角錐台形を裾部に有する突起
　　３　　六角錘台形を裾部に有する突起
　１０　　角錐台形の底面
　１１　　角錐台形の裾部
　１２　　凸な曲面形状の頂部
　１３　　円錐台形の裾部 DESCRIPTION OF SYMBOLS 1 Protrusion which has frustoconical shape in skirt part 2 Protrusion which has quadratic pyramid shape in hem part 3 Protrusion which has hexagonal frustum shape in hem part 10 Bottom surface of truncated pyramid 11 Bottom part of truncated pyramid shape 12 Top part of convex curved shape 13 Hem

Claims (5)

  1. 少なくとも一方の表面に、１ｃｍ２あたり４０個以上２３００個以下の突起を有する、熱可塑性樹脂からなる太陽電池封止材シートであって、前記突起は多角形を底面とする角錐台形の裾部と、凸な曲面形状である頂部とから構成され、該突起の以下に定義する頂部比率Ｘが０．１以上０．４以下であることを特徴とする太陽電池封止材シート。
    頂部比率Ｘの定義：
    （１）突起部の最頂部をＰ、前記最頂部Ｐを角錐台形の底面に投影した点をＰ’、Ｐ’から角錐台形の底面の任意の辺に引いた垂線の足をＱとし、これらの点（Ｐ，Ｐ’，Ｑ）を通る断面を取る。
    （２）点（Ｐ，Ｐ’，Ｑ）を通る断面において、線分Ｐ’Ｑを１０等分した区間を点Ｑより区間Ｒ１～Ｒ１０とし、線分Ｐ’Ｑ上の区間Ｒｊ（１≦ｊ≦１０）の境界点ｒｊ－１、ｒｊを通り、線分Ｐ’Ｑに直交する直線をＳｊ－１、Ｓｊとし、該直線と曲線ＰＱの交点をｔｊ－１、ｔｊとする。区間Ｒｊにおいて、点ｔｊ－１、ｔｊを結ぶ直線と、直線Ｐ’Ｑのなす鋭角をθｊとする。
    （３）（θ１＋θ２）／２　－θｊ≧４°（１≦ｊ≦１０）を満たす区間Ｒｊの数を求め、１０で除す。
    （４）上記（１）～（３）を底面の多角形の各辺に対して行い、平均したものを、その突起の頂部比率Ｘと定義する。     A solar cell encapsulant sheet made of a thermoplastic resin having 40 to 2300 protrusions per 1 cm 2 on at least one surface, the protrusions having a truncated pyramid shape with a polygonal bottom surface, A solar cell encapsulant sheet comprising: a top portion having a convex curved surface shape, and a top portion ratio X defined below of the protrusion is 0.1 or more and 0.4 or less.
    Definition of the top ratio X:
    (1) P is the top of the protrusion, P ′ is the point at which the top P is projected onto the bottom of the truncated pyramid, and Q is the perpendicular foot drawn from P ′ to any side of the bottom of the truncated pyramid. A cross section passing through the points (P, P ′, Q) is taken.
    (2) In a cross section passing through the point (P, P ′, Q), a section obtained by equally dividing the line segment P′Q by 10 is defined as sections R 1 to R 10 from the point Q, and a section R j on the line segment P′Q. The straight lines that pass through the boundary points r j−1 and r j of (1 ≦ j ≦ 10) and are orthogonal to the line segment P′Q are S j−1 and S j, and the intersection of the straight line and the curve PQ is t j− 1 and t j . In the section R j , an acute angle formed by the straight line connecting the points t j−1 and t j and the straight line P′Q is θ j .
    (3) The number of sections R j satisfying (θ 1 + θ 2 ) / 2 −θ j ≧ 4 ° (1 ≦ j ≦ 10) is obtained and divided by 10.
    (4) The above (1) to (3) are performed on each side of the bottom polygon, and the average is defined as the top ratio X of the protrusions.
  2. 前記角錐台形の底面の形状が三角形、四角形、五角形、または六角形である請求項１に記載の太陽電池封止材シート。 The solar cell encapsulant sheet according to claim 1, wherein the shape of the bottom surface of the truncated pyramid is a triangle, a quadrangle, a pentagon, or a hexagon.
  3. 前記点Ｐ’から前記角錐台形の底面の多角形の辺までの最短距離ＬＰ’と、前記角錐台形の底面の多角形の重心Ｇから前記底面の多角形の辺までの最短距離ＬＧとの比から求まる突起頂部の中心度ＬＰ’／ＬＧが０．５以上１以下である請求項１または２に記載の太陽電池封止材シート。 And 'shortest distance L P to the sides of the polygonal bottom face of the truncated pyramid from' the point P, a shortest distance L G from the center of gravity G of the polygonal bottom face of the truncated pyramid to the side of the polygon of the bottom surface solar cell encapsulant sheet according to claim 1 or 2 centrality L P '/ L G of the projecting apex which is obtained from the ratio of is 0.5 or more and 1 or less.
  4. 前記突起の高さをＨとし、前記突起の底面の外接円の直径をＤとしたとき、突起のアスペクト比Ｈ／Ｄが０．０３以上０．８０以下である請求項１～３のいずれかに記載の太陽電池封止材シート。 The aspect ratio H / D of the protrusion is 0.03 or more and 0.80 or less, where H is the height of the protrusion and D is the diameter of the circumscribed circle of the bottom surface of the protrusion. A solar cell encapsulant sheet as described in 1.
  5. 受光面保護材と、裏面保護材と、この受光面保護材と裏面保護材との間に配置され、請求項１～４のいずれかに記載の太陽電池封止材シートにより太陽電池セルが封止された層と、で構成された、太陽電池モジュール。 The solar cell is sealed by the solar cell sealing material sheet according to any one of claims 1 to 4, which is disposed between the light receiving surface protective material, the back surface protective material, and the light receiving surface protective material and the back surface protective material. A solar cell module composed of a stopped layer.
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