JP2015233095A - Solar battery unit and method for manufacturing solar battery unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a solar battery unit having good solar battery characteristics with solar battery cells arranged to be connected to wiring members via no bus-bar electrode; and a method for manufacturing such a solar battery unit.SOLUTION: A solar battery unit 1 comprises: solar battery cells 2; and wiring members 5 electrically connecting between the solar battery cells 2. Each solar battery cell 2 is bonded to the wiring member 5 by an adhesive member 6 via no bus-bar electrode 11 at least on the side of a light-receiving surface 2a of the solar battery cell 2. The adhesive member 6 has a total light transmittance of 50% or larger. According to this embodiment, light reaching under each wiring member 5 will be incident on the light-receiving surface 2a of the solar battery cell 2 underlying the wiring member 5, contributing to power generation and therefore, the solar battery characteristics can be enhanced.

Description

  The present invention relates to a solar cell unit and a method for manufacturing a solar cell unit.

  In the solar cell unit, a plurality of solar cells are connected in series and / or in parallel via bus bar electrodes and wiring members (tab wires) electrically connected to the surface electrodes (thin wire electrodes) of the solar cells. Have a structure. Since solar cells are used in outdoor environments, it is necessary to ensure resistance to temperature changes, moisture, strong winds, snow accumulation, etc., and the solar cell group to which the bus bar electrodes and wiring members are connected is sealed with a sealing member. It is common. Usually, a plurality of sealing members such as ethylene vinyl acetate (EVA) are sandwiched between tempered glass and a back sheet, and further sandwiched between the sealing members so as to laminate a group of solar cells to which wiring members are connected. Thereafter, sealing is performed by a vacuum laminator.

  Conventionally, solder has been used for joining the surface electrode and the wiring member when manufacturing the solar cell unit (see, for example, Patent Documents 1 and 2). Solder is widely used because it is excellent in connection reliability such as electrical conductivity and fixing strength, is inexpensive and versatile. However, in the soldering method, since the melting temperature of the solder is usually about 230 to 260 ° C., the high temperature accompanying the joining, the volumetric shrinkage of the solder, etc. adversely affect the semiconductor structure of the solar battery cell. It may cause characteristic deterioration.

  On the other hand, a joining method using an adhesive member without using solder is also known. For example, the following patent documents 3 to 5 disclose a joining method using a conductive paste, and the following patent documents 6 to 8 disclose a joining method using a conductive film. According to the joining method using these adhesive members, it becomes possible to join the surface electrode and the wiring member without using the bus bar electrode as in the solar cell unit described in Patent Document 9 below. By not interposing the bus bar electrode, the continuity between the surface electrode and the wiring member is excellent, and a stable connection state can be obtained by directly joining the wiring member and the solar battery cell. Further, in general, by not using a bus bar electrode containing Ag, the amount of Ag used in the solar cell unit is reduced, which contributes to cost reduction.

JP 2004-204256 A JP-A-2005-050780 JP 2000-286436 A JP 2001-357897 A Japanese Patent No. 3448924 JP 2005-101519 A JP 2007-214533 A JP 2008-300403 A JP 2013-51446 A

  In recent years, solar cells have attracted more and more attention as a means of supplying clean and undepleted energy, and further improvement of solar cell characteristics is expected. One means for improving the solar cell characteristics is to increase the light incident on the light receiving surface of the solar cell. However, for example, in the solar battery unit according to Patent Document 9 described above, an adhesive member, a wiring member, and the like are arranged on the light receiving surface side of the solar battery cell. For this reason, there is a problem that a part of the light is shielded or attenuated by an adhesive member, a wiring member or the like before entering the light receiving surface.

  The present invention has been made in view of the above problems, and in a solar cell electrically connected to a wiring member without a bus bar electrode, a solar cell unit and a solar cell unit having good solar cell characteristics It aims at providing the manufacturing method of.

  In order to solve the above problems, a solar battery unit according to the present invention is a solar battery unit including a plurality of solar battery cells and a wiring member that electrically connects the solar battery cells, at least of the solar battery cells. On the light receiving surface side, the solar cell and the wiring member are joined by the adhesive member, and the surface electrode of the solar cell and the wiring member are connected without the bus bar electrode, and the total light transmittance of the adhesive member is 50% or more.

  According to the solar cell unit of the present invention, by having the above-described configuration, the light that has traveled under the wiring member enters the light receiving surface of the solar cell under the wiring member and contributes to power generation. Characteristics can be improved.

  Moreover, it is preferable that the refractive index of an adhesive member is 1.4 or more and 3.6 or less. Thereby, light can be efficiently guided under the wiring member.

  In addition, it is preferable that a sealing member for sealing the solar battery cell to which the wiring member is bonded is further provided, and the refractive index of the adhesive member is equal to or higher than the refractive index of the sealing member. Thereby, reflection of light at the interface between the adhesive member and the sealing member can be suppressed, and light can be efficiently guided under the wiring member.

  Further, the haze of the adhesive member is preferably 90% or less.

  Moreover, it is preferable that the adhesive member contains metal particles. Thereby, connectivity, conductivity, elasticity, heat resistance, water resistance, gas barrier properties, and an appropriate refractive index can be imparted to the adhesive member.

  Moreover, it is preferable that a wiring member has an uneven | corrugated shape in at least one part of an outer surface. Thereby, the adhesiveness of a wiring member and an adhesive member improves.

  Moreover, it is preferable that the surface of a wiring member contains Ag. Thereby, the light which is reflected by the surface of a wiring member and injects into the light-receiving surface of a photovoltaic cell increases.

  The method for producing a solar cell unit according to the present invention is a method for producing the above-described solar cell unit, and an arrangement step of arranging an adhesive member and a wiring member in this order on the surface electrode of the solar cell, and an arrangement step And a connecting step of sandwiching the solar cell and the wiring member at a pressure of 0.1 MPa or more and 2.0 MPa or less and connecting the surface electrode and the wiring member.

  Moreover, it is preferable to arrange | position a film-like adhesive member on a surface electrode at an arrangement | positioning process. Thereby, a stable and uniform connection state is realized in the solar battery cell that is electrically connected to the wiring member without passing through the bus bar electrode.

  ADVANTAGE OF THE INVENTION According to this invention, the solar cell unit which has a favorable solar cell characteristic, and the manufacturing method of a solar cell unit are obtained in the photovoltaic cell electrically connected with a wiring member, without passing through a bus-bar electrode.

(A) It is a schematic diagram which shows the principal part of the surface side of the solar cell unit which concerns on this embodiment. (B) It is a schematic diagram which shows the principal part by the side of the back surface of the solar cell unit which concerns on this embodiment. It is typical sectional drawing which looked at the solar cell unit concerning this embodiment from the side. It is sectional drawing which shows typically the principal part of the solar cell unit which concerns on this embodiment. (A) It is a schematic diagram which shows the principal part by the side of the surface of the solar cell unit which concerns on a modification. (B) It is a schematic diagram which shows the principal part by the side of the back surface of the solar cell unit which concerns on a modification. It is sectional drawing which shows typically the principal part of the solar cell unit which concerns on a modification. It is sectional drawing which shows typically the principal part of the solar cell unit which concerns on a modification. (A) It is a schematic diagram which shows the principal part by the side of the surface of the conventional solar cell unit. (B) It is a schematic diagram which shows the principal part by the side of the back surface of the conventional solar cell unit. It is sectional drawing which shows the principal part of the conventional solar cell unit typically.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. The numerical range includes the upper and lower end values.

  FIG. 1 is a schematic diagram showing a main part of a solar cell unit according to the present embodiment, and shows an outline of a structure when a plurality of solar cells 2 are connected to each other as an example. Fig.1 (a) shows the surface side of the solar cell unit 1, and FIG.1 (b) shows the back surface side.

  FIG. 3 is a cross-sectional view schematically showing the main part of the solar cell unit according to the present embodiment. FIG. 3 is exaggerated for purposes of illustration. For example, the surface electrode 3 is provided on the light receiving surface 2a side of the solar battery cell 2 according to this embodiment, and the back electrode 4 is provided on the back surface 2b side. 2, the back electrode 4 is not shown. 5 to 8 are similarly exaggerated for the sake of explanation.

  In the solar battery cell 102 included in the conventional solar battery unit 101, as shown in FIGS. 7 and 8, a surface electrode 103 composed of a plurality of elongated linear electrodes is formed on the light receiving surface 102a. . A wiring member 105 having a smaller number than the surface electrode 103 and a width wider than the surface electrode 103 is arranged on the light receiving surface 102 a via the bus bar electrode 111 so as to be orthogonal to the surface electrode 103.

  In the solar cell unit 1 according to the present embodiment, as shown in FIGS. 1, 2, and 3, the light receiving surface 2 a that is the surface of the solar cell 2 is configured with a plurality of elongated linear electrodes. A surface electrode 3 (also referred to as a fine wire electrode or a finger electrode) is formed, and a back electrode 4 that covers the entire surface is formed on the back surface 2 b of the solar battery cell 2. The front surface electrode 3 is made of, for example, Ag, and the back surface electrode 4 is made of, for example, Al. On the back surface 2b side of the solar battery cell 2, the wiring member 5 (both the wiring wire or the tab wire) for connecting the solar battery cell 2 in series and / or in parallel to the back electrode 4 through the bus bar electrode 11 containing Ag. Is connected). On the other hand, on the light receiving surface 2 a side of the solar battery cell 2, the wiring member 5 is connected to the surface electrode 3 so as to be orthogonal to the surface electrode 3 without passing through the bus bar electrode 11.

  As a method of connecting the surface electrode 3 and the wiring member 5 without passing through the bus bar electrode 11, the bus bar electrode 11 is not disposed on the light receiving surface 2a side of the solar battery cell 2 having the surface electrode 3, and the surface electrode 3 There is a method of obtaining electrical connection with the wiring member 5.

  As a method of connecting the surface electrode 3 and the wiring member 5 without passing through the bus bar electrode 11, it is conceivable to join the surface electrode 3 and the wiring member 5 with solder. However, when joining with solder, since the surface electrode 3 and the wiring member 5 are joined only on the surface electrode 3, the joining strength may not be sufficient. Further, it is difficult to maintain an electrically stable connection state with respect to the surface electrode 3. Therefore, in the present embodiment, the light receiving surface 2a of the solar battery cell 2 and the wiring member 5 are joined by the adhesive member 6 so that the surface electrode 3 and the wiring member 5 are connected without the bus bar electrode 11 interposed therebetween. The adhesive member 6 provides the electrical conductivity indicated by the arrow A1 in FIG. 3 between the wiring member 5 and the surface electrode 3, and the adhesive indicated by the arrow A2 in FIG. 3 between the wiring member 5 and the solar battery cell 2. As a result, a stable and uniform connection state can be obtained. “The surface electrode 3 and the wiring member 5 are connected without the bus bar electrode 11” means that the wiring member 5 is directly connected to the surface electrode 3 of the solar battery cell 2.

  Here, examples of the surface electrode 3 include known materials capable of obtaining electrical conduction. For example, various conductive particles are dispersed in a general glass paste containing silver or an adhesive resin. Silver paste, gold paste, carbon paste, nickel paste, aluminum paste, ITO formed by firing or vapor deposition, and the like. Among these, a glass paste electrode containing silver is preferably used from the viewpoints of heat resistance, conductivity, stability, and cost.

  Examples of the solar battery cell 2 include crystal solar battery cells such as single crystal silicon and polycrystalline silicon, and thin film solar battery cells such as amorphous silicon, CIGS, and CdTe. As a typical example, a solar battery cell in which an Ag electrode and an Al electrode are provided as a surface electrode 3 on a substrate made of at least one of Si single crystal, polycrystal, and amorphous by screen printing or the like. 2 is mentioned. As shown in FIGS. 4, 5, and 6, the solar battery cell 2 has a surface electrode 3 made of Ag on both front and back surfaces, and a double-sided light receiving type in which an antireflection film and a passivation layer are provided on both front and back surfaces. The solar cell units 31 and 41 may be used. Details of the solar cell units 31 and 41 will be described later.

  Examples of the material of the adhesive member 6 include epoxy resin, acrylic resin, phenoxy resin, melamine resin, polyurethane resin, polyester resin, polyethylene resin, polyimide resin, polyamide resin, phenol resin, and silicon resin. It can be used, or it can be used as a mixture, a copolymer, etc. which combined 2 or more types. Among these, it is preferable that at least one of an epoxy resin, a phenoxy resin, a polyethylene resin, and an acrylic resin is contained in the adhesive member 6 from the viewpoint of connection reliability.

  These adhesive members 6 have a total light transmittance of 50% or more so that the light that travels under the wiring member 5 enters the solar cells 2 under the wiring member 5 and contributes to power generation. The total light transmittance is more preferably 70% or more, and the total light transmittance is more preferably 80% or more.

  The haze of the adhesive member 6 is defined in JIS K 7136-1: 2000. The haze is preferably 90% or less, and preferably 70% or less so that the light that travels under the wiring member 5 enters the solar cells 2 under the wiring member 5 and contributes to power generation. Is more preferable, and it is still more preferable that it is 50% or less.

  Although the total light transmittance is specified in JIS K 7361-1: 1997, the wavelength sensitivity of the crystalline silicon solar cell is high at 600 nm to 1100 nm, and the wavelength sensitivity of the amorphous silicon solar cell is high at 300 nm to 600 nm. According to the material of 2, it is preferable that the transmittance in each wavelength sensitivity band is high.

  In addition, the refractive index of the adhesive member 6 is preferably 1.4 or more and 3.6 or less, and is preferably 1.48 or more in order to efficiently guide light that travels under the wiring member 5 to the lower side of the wiring member 5. More preferably. In particular, the refractive index of the adhesive member 6 is more preferably equal to or higher than the refractive index of the sealing member 8 described later.

  In general, the refractive index of the resin is 1.49 to 1.53 for acrylic resin, 1.55 to 1.66 for epoxy resin, 1.53 to 1.6 for polyethylene resin, and 1.5 to 1 for polystyrene resin. 1.6, polyester resin 1.60, MBS resin (methyl methacrylate, butadiene, styrene copolymer) 1.54, silicone resin 1.43, cyanoacrylate resin 1.48-1.49, butyl rubber Is 1.51 and polycarbonate resin is 1.59. These resins can be used alone or in combination of two or more.

Furthermore, the adhesive member 6 may contain metal particles for imparting connectivity, electrical conductivity, elasticity, heat resistance, water resistance, gas barrier properties, an appropriate refractive index, and the like. For example, an adhesive member 6 containing metal particles, a wiring member 5, etc. are arranged in the solar battery cell 2, and they are pressure-bonded so that the metal particles bite into the surface electrode 3 and the wiring member 5. You may improve electroconductivity, the intensity | strength of joining, etc. As the metal particles, metal oxide particles, particles covered with a metal film, particles covered with a metal oxide film, and the like can be used. These particles include gold, Ag, Cu, Ni, lead, tin, bismuth, solder, gold / nickel plated plastic particles, copper plated particles, nickel plated particles, solder plated particles, ZnO, ITO, SiO ₂ , alumina, Examples thereof include titanium oxide, indium oxide, tin oxide, tantalum oxide, aluminum oxide, and zirconium oxide. In addition, these metal particles preferably have a particle shape such as a chestnut shape or a spherical shape from the viewpoint of the embedding property of the metal particles to the adherend surfaces during bonding. That is, the metal particles having such a shape have high embeddability even with respect to the complicated uneven shape of the outer surface 5a of the surface electrode 3 and the wiring member 5 of the solar battery cell 2, and fluctuations such as vibration and expansion after joining. Therefore, the connection reliability can be further improved.

  The particle size of the metal particles is preferably in the range of 1 μm to 50 μm, and more preferably in the range of 1 μm to 30 μm.

  The content of the metal particles in the adhesive member 6 may be in a range in which the total light transmittance, adhesiveness, and the like of the adhesive member 6 are not significantly reduced. For example, the volume is preferably 10% by volume or less based on the total volume of the adhesive member 6. May be 0.1-7% by volume.

  For example, the adhesive member 6 may be formed as a film by applying a coating solution obtained by dissolving or dispersing the above-described various materials in a solvent onto a release film such as a polyethylene terephthalate film and removing the solvent. The film-like adhesive member 6 thus obtained is superior to the paste-like adhesive member 6 in terms of film thickness dimensional accuracy and pressure distribution at the time of pressure bonding. In addition, by using a film shape, uniform and stable connection is possible when connecting without passing through the bus bar electrode 11, which contributes to improvement in yield, reliability, and the like.

  In the above, an example of a plastic film is given as the release film, but an adhesive film integrated with the wiring member 5 can also be obtained by using a metal film as the release film.

  The thickness of the adhesive member 6 in the case of forming a film can be controlled by adjusting the non-volatile content in the coating solution and adjusting the gap between the applicator and the lip coater. The thickness of the film-shaped adhesive member 6 is preferably 5 μm to 50 μm, and more preferably 10 μm to 35 μm.

The wiring member 5 is preferably a wire-like metal. Examples of the metal include gold, Ag, Cu, Ni, lead, tin, bismuth, solder, ZnO, ITO, SiO ₂ , Al, alumina, titanium oxide, indium oxide, tin oxide, tantalum oxide, aluminum oxide, zirconium oxide, and the like. Is mentioned. The wiring member 5 may be composed of two or more types using the above metals for the core material and the covering material, respectively. Among these, in order to reflect incident light efficiently, the outermost surface is preferably solder, Al, Ag, or the like.

  The outer surface 5a of the wiring member 5 is formed with a concavo-convex shape in order to scatter incident light and increase the light incident on the light receiving surface 2a of the solar battery cell 2 and to improve the adhesion to the adhesive member 6. It is preferable. The maximum uneven step is 0.1 μm to 200 μm, more preferably 1 μm to 150 μm, and even more preferably 5 μm to 100 μm. In order to securely connect the surface electrode 3 and the wiring member 5, it is preferable that the concavo-convex shape is provided on the outer surface 5 a of the wiring member 5, and stripe-shaped concavo-convex is formed in the longitudinal direction of the wiring member 5. The uneven shape may be formed on the entire outer surface 5 a of the wiring member 5, on one side, or on both sides.

  The solar cell unit 1 configured as described above can be manufactured by the following method. First, the arrangement | positioning process which arrange | positions the adhesive member 6 and the wiring member 5 in this order on the surface electrode 3 of the photovoltaic cell 2 is performed. Next, after the disposing step, a connecting step of sandwiching the solar battery cell 2 and the wiring member 5 with a pressure of 0.1 MPa or more and 2.0 MPa or less and connecting the surface electrode 3 and the wiring member 5 is performed. In the connecting step, the adhesive member 6 can be bonded to the wiring member 5 by heating, ultraviolet rays, pressure, or the like. In order to facilitate the bonding, to reliably cure the resin, and to ensure the contact between the wiring member 5 and the surface electrode 3, it is particularly preferable to perform bonding (thermocompression bonding) by heating and pressurization. In order to prevent damage to the solar battery cell 2, the connection temperature is preferably 50 ° C. to 200 ° C., and more preferably 80 ° C. to 180 ° C. Moreover, about a pressure, 0.05 MPa or more and 2.5 MPa or less are preferable, and 0.1 MPa or more and 2.0 MPa or less are more preferable. Or you may join to the other sealing member 8 collectively only by the sealing process by a lamination. The conditions for the sealing step by laminating are usually determined by the crosslinking conditions such as EVA generally used as the sealing member 8, but generally the conditions such as holding at 150 ° C. for about 10 minutes. Can be mentioned. By connecting the surface of the wiring member 5 into at least a part of the bus bar electrode 11 by thermocompression bonding or laminating, the connection state may be made more reliable.

  The solar cell array composed of the solar cell 2, the adhesive member 6, and the wiring member 5 is further installed in a laminator device in a state where a sealing member 8, such as EVA, and glass are laminated, and the solar cell is subjected to a sealing process. It becomes unit 1.

  The solar cell unit 1 according to this embodiment thus manufactured provides good solar cell characteristics in a solar cell in which the solar cells 2 and the wiring member 5 are joined without the bus bar electrode 11 interposed therebetween. be able to.

  As shown in FIG. 1 (a), FIG. 1 (b), and FIG. 4, the solar cell unit 1 includes a surface electrode 3 (thin wire electrode) on the light receiving surface 2a side and a back electrode 4 on the back surface 2b side. A plurality of battery cells 2 are connected to each other by a wiring member 5. Then, one end side of the wiring member 5 is joined to the thin wire electrode as the surface electrode 3 by being joined by the adhesive member 6 on the light receiving surface 2 a of the solar battery cell 2. The other end side of the wiring member 5 is connected to the bus bar electrode 11 on the back surface 2 b of the solar battery cell 2.

  Since the surface electrode 3 and the wiring member 5 are connected as described above, the solar cell unit 1 having such a configuration can obtain good solar cell characteristics.

  As a method for evaluating whether the solar battery cell 2 and the wiring member 5 are appropriately joined, a current-voltage (IV) curve measurement using a solar simulator can be given. The product of the short-circuit current (Isc) and the open circuit voltage (Voc) obtained at this time can be evaluated by the value of the curve factor (FF) obtained by dividing the product by the maximum current value (Pmax).

  In FIG. 3, typical sectional drawing of the laminated body installed in the laminator apparatus when the solar cell unit 1 is produced through the sealing process mentioned above is shown. In this laminate, glass 9, sealing member 8, wiring member 5, adhesive member 6, solar battery cell 2, bus bar electrode 11, wiring member 5, sealing member 8, and backsheet 10 are arranged in this order from the surface side. Has been. The solar cell 2 is provided with a surface electrode 3 on the light receiving surface 2a side and a back electrode (not shown) on the back surface 2b side. The wiring member 5 is disposed at a position orthogonal to the surface electrode 3 of the solar battery cell 2.

  Examples of the glass 9 include white plate tempered glass with dimples for solar cells. An example of the sealing member 8 is an EVA sheet made of EVA. Examples of the wiring member 5 include a tab wire obtained by dipping or plating a solder on a Cu wire. Examples of the backsheet 10 include PET-based or tedla-PET laminate materials, metal foil-PET laminate materials, and the like.

  The present invention is not limited to the above embodiment. For example, although the single-sided light receiving type solar cell unit 1 has been exemplified in the above embodiment, the present invention can also be applied to the double-sided light receiving type solar cell units 31 and 41 as shown in FIG. In the double-sided light receiving type solar battery unit 31, as shown in FIG. 5, the solar battery cell 2 has a front surface electrode 3 (thin wire electrode) also on the back surface 2b side. And the adhesive member 6 and the wiring member 5 are arrange | positioned at the surface electrode 3 by the side of the back surface 2b of the photovoltaic cell 2, and the back surface 2b and wiring member of the photovoltaic cell 2 are provided by means, such as a heating, irradiation of an ultraviolet-ray, provision of a pressure. 5 are joined. Thereby, it electrically connects between the surface electrode 3 by the side of the back surface 2b of the photovoltaic cell 2, and the wiring member 5, and favorable electroconductivity is obtained. Moreover, in the solar cell unit 31, the sealing member 8 and the back sheet 10 are further laminated | stacked with respect to the wiring member 5 arrange | positioned at the back surface 2b side of the photovoltaic cell 2. FIG. Thereby, even when the light incident from the light receiving surface 2 a side does not enter the solar battery cell 2 and passes through the back surface 2 b side, it is reflected by the back sheet 10 and enters the back surface 2 b of the solar battery cell 2. By doing so, efficient power generation becomes possible.

Further, in the double-sided light receiving type solar cell unit 41, as shown in FIG. 6, the solar cell 2 also has a surface electrode 3 (fine wire electrode) on the back surface 2b side, and further an adhesive member 6 and a wiring member 5 are arranged. It is common to the solar cell unit 31 in that it is. However, in the solar cell unit 41, the glass 9 is arranged instead of the back sheet 10 on the back surface 2 b side of the solar cell 2. Thereby, the light incident from the back surface 2b side passes through the glass 9, the sealing member 8, and the adhesive member 6 on the back surface 2b side, and enters the back surface 2b of the solar battery cell 2, thereby generating efficient power generation. It becomes possible.
[Example]

EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.
<Production of Adhesive Film (Adhesive Member 6) and Production of Solar Cell Unit 1>
(Example 1)
(Production of polyethylene resin film (adhesive member 6))

  100 g of ethylene-vinyl acetate resin (EVA) manufactured by Tosoh Corporation as a transparent dispersion medium resin: Ultrasen 634 (not containing an ultraviolet absorber), a peroxide thermal radical polymerization initiator manufactured by Arkema Yoshitomi Corporation: Luperox A wavelength conversion resin composition was obtained by kneading 1.5 g of 101 and 0.5 g of silane coupling agent: SZ6030 manufactured by Toray Dow Corning Co., Ltd. with a roll mill.

About 30 g of the resin composition for wavelength conversion obtained above was sandwiched between release sheets, and 0.030 mm thick stainless steel spacers were used, and a hot plate was adjusted to 80 ° C. to form a sheet. This was slit to a width of 1.5 mm to obtain a polyethylene resin film having a film thickness of 25 μm. The total light transmittance of this polyethylene resin film was 89.20%. In addition, the total light transmittance of the polyethylene resin film was measured with a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH5000) using the cured film.
(Production of solar cell unit 1)

  Using the polyethylene resin film on the light receiving surface 2a of the solar battery cell 2 (156 mm × 156 mm, polycrystalline silicon) in which the bus bar electrode 11 is not formed and only the thin wire electrode as the surface electrode 3 is formed, A tab wire (Hitachi Cable Co., Ltd., SSA-TPS) as the wiring member 5 was connected.

  A crimping head for crimping from above the wiring member 5 (tab wire) of the solar battery cell 2 on which the wiring member 5 (tab wire) is placed, and a dedicated thermocompression bonding machine equipped with a heating mechanism (Shibaura Mechatronics Co., Ltd.) The wiring member 5 (tab wire) and the solar battery cell 2 were bonded by thermocompression over 30 seconds so that the temperature of the polyethylene resin film was 180 ° C. and the pressure applied to the bonded portion was 2 MPa.

  Next, the solar cell 2 to which the wiring member 5 (tab wire) is joined is reinforced glass (manufactured by Asahi Glass Co., Ltd.), the sealing member 8 is ethylene-vinyl acetate resin (EVA, refractive index 1.54), back sheet 10 is laminated in the order of glass 9 / EVA / solar cell 2 / EVA / backsheet 10, and this laminate is placed in a vacuum laminator, evacuated at 150 ° C. for 5 minutes, and maintained for 5 minutes. Was laminated to prepare a solar cell unit 1.

  About the obtained solar cell unit 1, IV curve was measured using the solar simulator (WXS-155S-10, AM1.5G) by Wacom Denso Co., Ltd., and the short circuit current Isc was calculated | required from this IV curve.

The short-circuit current Isc was 9360 mA, and it was confirmed that sufficient characteristics as a solar cell were obtained.
(Example 2)
(Production of epoxy resin film (adhesive member 6))

50 g of phenoxy resin (high molecular weight epoxy resin) (product name “PKHC” manufactured by Union Carbide), 20 g of epoxy resin (product name “YL-980” manufactured by Japan Epoxy Resin Co., Ltd.) and 5 g of imidazole were added to ethyl acetate. A 30% by mass ethyl acetate solution was prepared. The obtained mixed composition was applied onto a polyethylene terephthalate film using an applicator (manufactured by YOSHIMISU), and dried on a hot plate at 70 ° C. for 10 minutes to produce an epoxy resin film having a thickness of 25 μm. The total light transmittance of this epoxy resin film was measured in the same manner as in Example 1. As a result, it was 74.46%.
(Production of solar cell unit 1)

  The wiring member 5 (tab wire) is connected to the solar battery cell 2 using the epoxy resin film, and the wiring member 5 (tab wire) is connected so that the joining temperature is 180 ° C. and the pressure applied to the joining portion is 2 MPa. A solar cell unit 1 was produced in the same manner as in Example 1 except that the solar cells 2 were joined by thermocompression bonding over 10 seconds. About the obtained solar cell unit 1, it carried out similarly to Example 1, and calculated | required the short circuit current Isc.

The short-circuit current Isc was 9096 mA, and it was confirmed that sufficient characteristics as a solar cell were obtained.
(Example 3)

  An ethyl acetate solution of Example 2 was prepared, and Ni particles having an average particle diameter of 5 μm were added thereto in an amount of 5% by volume based on the total volume of the solid component, and an epoxy resin film having a total light transmittance of 55.21% was used. The solar cell unit 1 was produced in the same manner as in Example 2 except that the wiring member 5 (tab wire) was joined to the solar cell 2. About the obtained solar cell unit 1, the short circuit current Isc was calculated | required like the above.

The short-circuit current Isc was 9090 mA, and it was confirmed that sufficient characteristics as a solar cell were obtained.
Example 4

  The wiring member 5 (tab wire) was connected to the solar battery cell 2 using the cyanoacrylate resin (trade name “Aron Alpha” manufactured by Toagosei Co., Ltd.) having a total light transmittance of 100%, and the resin of Example 1 was joined. The same as in Example 1 except that the tab wire and the solar battery cell 2 were subjected to thermocompression bonding over 30 seconds so that the temperature was 100 ° C. and the pressure applied to the joining portion was 2 MPa, and then left to stand for 30 minutes at room temperature. A solar cell unit 1 was produced. Moreover, resin was apply | coated on the glass substrate and it measured in the state which set the film thickness of hardening to 25 micrometers. About the obtained solar cell unit 1, the short circuit current Isc was calculated | required like the above.

The short-circuit current Isc was 9069 mA, and it was confirmed that sufficient characteristics as a solar cell were obtained.
(Comparative Example 1)

  A butyl rubber film (manufactured by Nitto Shinko Co., Ltd., butyl rubber tape No. 11) was stretched using a glass rod to form a sheet having a thickness of 25 μm. This was slit to a width of 1.5 mm to obtain a butyl rubber film. The total light transmittance of this butyl rubber film was measured and found to be 6.42%. The wiring member 5 (tab wire) is connected to the solar battery cell 2 using the resin of Example 1 so that the joining temperature is 120 ° C. and the pressure applied to the joining portion is 2 MPa. A solar battery unit 1 was produced in the same manner as in Example 1 except that the solar battery cell 2 was joined by thermocompression bonding over 50 seconds. About the obtained solar cell unit 1, the short circuit current Isc was calculated | required like the above.

  The short circuit current Isc was 8843 mA.

The results are shown in Table 1.

  DESCRIPTION OF SYMBOLS 1,31,41 ... Solar cell unit, 2 ... Solar cell, 2a ... Light-receiving surface, 3 ... Surface electrode, 5 ... Wiring member, 5a ... Outer surface, 6 ... Adhesive member, 8 ... Sealing member, 11 ... Busbar electrode .

Claims (9)

A solar cell unit comprising a plurality of solar cells and a wiring member that electrically connects the solar cells,
At least on the light receiving surface side of the solar battery cell, the solar battery cell and the wiring member are joined by an adhesive member, and the surface electrode of the solar battery cell and the wiring member are connected without interposing a bus bar electrode. ,
The solar cell unit whose total light transmittance of the said adhesive member is 50% or more.   The solar cell unit according to claim 1, wherein a refractive index of the adhesive member is 1.4 or more and 3.6 or less. A sealing member for sealing the solar battery cell to which the wiring member is bonded;
The solar cell unit of Claim 1 or 2 whose refractive index of the said adhesive member is more than the refractive index of the said sealing member.   The solar cell unit according to claim 1, wherein the adhesive member has a haze of 90% or less.   The solar cell unit according to claim 1, wherein metal particles are included in the adhesive member.   The said wiring member is a solar cell unit as described in any one of Claims 1-5 which has uneven | corrugated shape in at least one part of an outer surface.   The solar cell unit according to any one of claims 1 to 6, wherein a surface of the wiring member contains Ag. A method for producing the solar cell unit according to claim 1,
An arrangement step of arranging the adhesive member and the wiring member in this order on the surface electrode of the solar battery cell,
A solar cell unit including, after the placing step, a connecting step of sandwiching the solar battery cell and the wiring member at a pressure of 0.1 MPa or more and 2.0 MPa or less and connecting the surface electrode and the wiring member. Manufacturing method.   The manufacturing method of the solar cell unit according to claim 8, wherein in the arranging step, the film-like adhesive member is arranged on the surface electrode.

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