JP2015115368A - Solar battery module and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solar battery module of high power generation efficiency, by increasing the contribution ratio to power generation, of the incident light to an intercell region.SOLUTION: In a light-receiving surface side sealant 4a of a solar battery module 1, a wavelength conversion layer 2 where phosphor particles 2b are dispersed is formed in an intercell region R. The phosphor particles 2b use a material absorbing the light of a specific wavelength region, and emitting the light of longer wavelength. An end face 2T of the wavelength conversion layer 2 facing a solar battery cell is inclining to face a light-receiving surface 6A of solar battery cells 6. With such a configuration, the incident light can be condensed onto a cell by performing wavelength conversion of the light incident to the intercell region Rof adjoining solar battery cells 6, and using the wavelength conversion layer 2 as a waveguide.

Description

  The present invention relates to a solar cell module and a manufacturing method thereof, and more particularly to a wavelength conversion type solar cell module.

  In general, a Si crystal solar cell module is composed of a plurality of solar cells, and converts light incident on the cells into electric power. These cells are arranged with a gap of about 1 to 4 mm in the horizontal plane of the module, and are electrically connected by tab wires. Therefore, there is a region on the module surface where no cell exists and does not directly contribute to power generation. For example, it is assumed that one module is composed of 50 cells, and each cell is arranged in 5 rows of 10 cells at equal intervals of 4 mm. In addition, assuming that each cell has an octagonal shape with a square corner of 156 mm square, the cell gap region (hereinafter referred to as an inter-cell region) occupies approximately 15% of the module surface area. In order to reduce the inter-cell area and improve the conversion efficiency of the solar cell module, it is effective to reduce the cell interval. However, in reality, since the stress of the tab line increases and cell cracking and wiring peeling occur, it is not easy to narrow the cell interval.

  On the other hand, the light incident on the inter-cell region does not contribute to power generation at all. In the solar cell module, a part of the light incident on the above-mentioned inter-cell region is reflected by the back sheet, and further reflected again at the light-transmitting surface-side translucent substrate and the air layer interface, so that the surface of the solar cell (Hereinafter referred to as indirect incident light). With this effect, a part of the incident light to the inter-cell region of the solar battery cell can be used for power generation. In order to increase the indirect incident light to the solar battery cell, a technique for diffusing the light incident on the inter-cell region as much as possible and increasing the amount of reflected light on the surface of the translucent substrate is required. Therefore, for example, Patent Document 1 proposes a module having a structure in which the diffuse reflectance is increased by forming irregularities on the back sheet. Patent Document 2 discloses a module structure in which a light-receiving surface side sealing material in a region between cells has a triangular recess structure, and this layer is a layer having a refractive index different from that of the surrounding sealing material (for example, an air layer). ing. Indirect incident light is increased by refracting and diffusing incident light in this air layer. Furthermore, Patent Document 3 discloses a configuration in which a wavelength conversion layer is provided on the light-receiving surface side of the solar battery cell, and a slope that reflects light reaching the side edge of the wavelength conversion layer is provided. As in the above example, a technique for effectively utilizing incident light to an inter-cell region for the purpose of improving module conversion efficiency is disclosed.

JP 2012-79772 A JP 2011-29273 A JP 2012-216620 A

  However, according to the above conventional technique, although effective use of incident light to the inter-cell region has been studied, almost no ultraviolet light having a wavelength of 400 nm or less has been used for power generation. The reason is the following two points.

  The first is light loss due to the sealing material and the back sheet. The solar cell module has a structure in which solar cells are sealed between a light-transmitting substrate on the front surface and a back sheet on the back surface by a sealing material having a thickness of about 0.5 mm. The thickness of the translucent substrate is 3.2 mm. For this reason, the optical path length until light incident perpendicularly to the cell directly enters the cell is about 3.7 mm, whereas the optical path length of indirect incident light is 11.7 mm or more, which is three times longer. In addition, light loss of 10% or more occurs due to light transmission and absorption in the backsheet. Due to the absorption / transmission loss due to these members, the proportion of short-wavelength light that is particularly susceptible to absorption / scattering among the incident light to the inter-cell region significantly decreases.

  The second is due to the difference in spectral sensitivity for each wavelength of the solar battery cell. The spectral sensitivity of the solar battery cell is not constant over the entire wavelength range, and varies depending on the material characteristics of the solar battery element. In particular, in a heterojunction type single crystal Si solar cell, the contribution to the power generation of light in a short wavelength region such as ultraviolet light to near ultraviolet light is about half or less of visible light.

  The present invention has been made in view of the above, and reduces the optical path length until the light incident on the inter-cell region indirectly enters the solar cell, and at the same time, the wavelength suitable for power generation of the solar cell. An object is to obtain a solar cell module with high conversion efficiency and a method for manufacturing the solar cell module.

  In order to solve the above-described problems and achieve the object, the solar cell module of the present invention includes a wavelength conversion layer in the inter-cell region on the light receiving surface side, and the light incident on this layer has a wavelength with higher cell spectral sensitivity. Has the function of converting to light. This wavelength conversion layer has an inclined end surface formed obliquely so that the end surface faces the light receiving surface of the solar battery cell.

  According to the present invention, ultraviolet light incident on the inter-cell region can be converted into light having a wavelength with high spectral sensitivity of the cell by the wavelength conversion layer. Furthermore, by using the wavelength conversion layer as a waveguide, it is possible to reflect the light incident on the inter-cell region within the wavelength conversion layer and collect it on the cell. Due to this effect, the light incident on the inter-cell region in the solar cell module of the present invention has a significantly reduced optical path length to the cell as compared with the indirect incident light due to reflection on the conventional backsheet. Therefore, according to the said structure, since the synergistic effect of the above-mentioned wavelength conversion effect | action and a condensing effect | action is acquired, it is very effective for the conversion efficiency improvement of a solar cell module.

  In addition, since it is possible to reduce the ultraviolet light reaching the back sheet, deterioration phenomena such as yellowing of the back sheet due to ultraviolet light can be prevented. Thereby, it can contribute also to the lifetime improvement and reliability improvement of a solar cell module. Alternatively, since the necessity of countermeasures against ultraviolet rays on the back sheet side is reduced, the cost of the back sheet can be reduced, and the price of the solar cell module can be reduced.

1A and 1B are diagrams showing a solar cell module according to Embodiment 1, wherein FIG. 1A is a schematic cross-sectional view of the solar cell module, and FIG. 1B is a schematic cross-sectional view of a solar cell used here. It is. FIG. 2 is a diagram schematically illustrating the behavior of light inside the wavelength conversion layer. FIGS. 3A and 3B are diagrams showing a manufacturing process of the light-receiving surface side sealing material used in the solar cell module of the first embodiment. FIG. 4 is an exploded perspective view of the solar cell module according to the first embodiment. FIG. 5 is a schematic cross-sectional view showing a modification of the solar cell module according to the first embodiment. FIG. 6 is a schematic cross-sectional view showing another modification of the solar cell module according to the first embodiment. FIG. 7 is a schematic cross-sectional view of the solar cell module according to the second embodiment. FIGS. 8A to 8E are schematic cross-sectional views illustrating the manufacturing process of the solar cell module of the second embodiment. FIG. 9 is a schematic cross-sectional view of the solar cell module according to the third embodiment. FIG. 10 is a schematic cross-sectional view of the solar cell module according to the fourth embodiment. FIGS. 11A to 11C are schematic cross-sectional views illustrating the manufacturing process of the light-receiving surface side sealing material used in the solar cell module of the fourth embodiment. FIG. 12 is a schematic cross-sectional view of the solar cell module according to the fifth embodiment. FIG. 13 is a schematic cross-sectional view of the solar cell module according to the sixth embodiment. FIG. 14 is a schematic cross-sectional view of a translucent substrate used in the solar cell module according to the sixth embodiment. FIG. 15 is an exploded perspective view of the solar cell module according to the seventh embodiment. FIG. 16 is an exploded perspective view of the solar cell module according to the eighth embodiment. FIG. 17 is an enlarged schematic diagram of a main part of the solar cell module according to the eighth embodiment.

  Embodiments of a solar cell module and a manufacturing method thereof according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings. Further, even a plan view may be hatched to make the drawing easy to see.

Embodiment 1 FIG.
(Configuration of wavelength conversion type solar cell module)
First, the configuration of the solar cell module according to Embodiment 1 will be described. FIG. 1A is a schematic cross-sectional view of the solar cell module 1 of the first embodiment, and FIG. 1B is a schematic cross-sectional view of the solar cell 6 used here. This solar cell module 1 includes a plurality of solar cells 6, a light receiving surface side sealing material 4a that covers the light receiving surface 6A of the solar cells 6, and a back surface 6B that is a surface facing the light receiving surface 6A of the solar cells. The back surface side sealing material 4b which covers is integrally sealed. The light receiving surface side sealing material 4 a is disposed in the inter-cell region of the adjacent solar cells 6, and the wavelength opposite to the solar cells 6 is formed obliquely with respect to the light receiving surface 6 </ b> A of the solar cells 6. A conversion layer 2 and a light receiving surface side sealing layer that contacts the wavelength conversion layer 2 and contacts the light receiving surface side of the solar battery cell are provided. This wavelength conversion layer 2 forms an inclined end face that is formed so that the end face 2T facing the solar battery cell 6 faces the light receiving face of the solar battery cell. This solar battery module 1 is further sealed on the light receiving face side. The outer sides of the material 4 a and the back surface side sealing material 4 b are sandwiched between the translucent substrate 5 and the back sheet 8. A plurality of solar cells are arranged with an interval of 1 mm or more, and are electrically connected by an interconnector 7. Here, the light-receiving surface side sealing material 4a and the back surface side sealing material 4b are made of the same resin, and are melted and cured to form the sealing material 4.

In the inter-cell area R _I of the adjacent solar cells 6 each other, the phosphor particles 2b to form the wavelength conversion layer 2 dispersed in a matrix 2a in a partial region of the light-receiving-side sealing member 4a. The surface of the wavelength conversion layer in the thickness direction (hereinafter referred to as end surface 16) is designed to be inclined with respect to the horizontal plane of the solar cell module. As an example of a structure that satisfies this condition, the cross-sectional structure of the wavelength conversion layer 2 is trapezoidal as shown in FIG.

  The wavelength conversion layer 2 is composed of a mixture of a base material 2a made of a thermoplastic resin and phosphor particles 2b as functional particles of the wavelength conversion material. The wavelength conversion material is a downshift material that converts light having a wavelength of about 300 to 400 nm into light having a wavelength of about 400 to 900 nm.

  These wavelength conversion materials may be dispersed in a light-transmitting polymer material such as an acrylic resin or a silicone resin. It can be formed into a solution using an appropriate solvent, and formed by sputtering, printing, spray coating, or the like. Furthermore, the density of the phosphor particles 2b in the wavelength conversion layer 2 is not necessarily uniform. In the wavelength conversion layer 2, the density of the phosphor particles 2 b is increased in a region close to the translucent substrate 5, and the concentration near the bottom surface is decreased, thereby condensing light due to changes in the phosphor usage as a whole or the refractive index. Sex can be controlled.

The wavelength conversion material converts light having a wavelength of about 300 to 400 nm into light having a wavelength of about 400 to 900 nm. For example, the excitation wavelength is about 300 to 500 nm, which is close to ultraviolet light, and the emission wavelength is about 500 to 500 of visible light. CaAlSiN ₃ : Eu ²⁺ which is about 700 nm is used. Other inorganic fluorescent agents include zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), cadmium sulfide (CdS); Er ³⁺ , Yb ³⁺ , Ho ³⁺ , Pr ³⁺ , An inorganic fluorescent agent containing a rare earth complex such as a rare earth-containing YAG (yttrium, aluminum, garnet) containing a rare earth element such as Eu ³⁺ may be used. Further, it is possible to appropriately select a phosphor such as an organic phosphor or an organometallic complex as required. In other words, the wavelength conversion layer absorbs light in a specific wavelength region and emits fluorescent material such as inorganic phosphor, organic phosphor, organometallic complex, and rare earth complex that emits light having a longer wavelength than the absorbed light. It can be formed by dispersing it in a resin, glass, film or the like.

  The solar battery cell 6 is provided with current collecting electrodes 66a and 66b on the front surface of the light receiving surface 6A and the front surface of the rear surface 6B, and the electrodes of the adjacent solar battery cells 6 arranged in series are interconnected by an interconnector 7.

  In addition, as will be described later, it is a diagram showing the solar cell module 1 in which twelve solar cells 6 are connected in series, but the number and arrangement can be arbitrarily changed, and parallel connection may be combined. Although not shown in the drawing, lead wires for taking out electric power to the back side of the solar cell module 1 are connected to both ends of the solar cell module 1.

  As the glass plate as the translucent substrate 5, for example, a material such as soda lime glass can be used. In a solar cell module used outdoors, a glass plate that has been thermally or chemically reinforced may be used as the light-receiving surface side protective material. The size of the glass plate can be variously changed depending on the number of solar cells 6, but a typical thickness is 0.5 to 3 mm. As the back film 8, a film having a low moisture permeability or a glass plate similar to the front side is used so that the solar battery cell 6 does not deteriorate due to the ingress of moisture. In order to reflect the solar cell 6 and the light passing through the gap between the solar cell 6 and the solar cell 6, a white or metal light reflective material may be used as the back film 8. As the sealing material 4, translucent EVA, silicone resin, or the like can be used. For the interconnector 7, for example, a copper wire coated with solder can be used.

  FIG.1 (b) is sectional drawing which shows schematic structure of the photovoltaic cell 6 used with the solar cell module 1 by Embodiment 1 of this invention. The n-type semiconductor substrate is a thin semiconductor substrate made of crystalline silicon such as single crystal silicon or polycrystalline silicon, a compound semiconductor, or the like. In this embodiment, an n-type single crystal silicon substrate 61 is used. In the case of crystalline silicon, the typical substrate size is approximately 10 to 15 cm square, and the thickness is 0.1 to 0.3 mm.

  i-type amorphous silicon layers 62 a and 62 b are formed on both surfaces of n-type single crystal silicon substrate 61. On the i-type amorphous silicon layer 62a, a p-type amorphous silicon layer 63 containing impurities of a conductivity type opposite to that of the n-type single crystal silicon substrate 61 is formed. An impurity of the same conductivity type as that of the n-type single crystal silicon substrate 61 is included on the i-type amorphous silicon layer 62b formed on the substrate surface opposite to the side where the p-type amorphous silicon layer 63 is formed. An n-type amorphous silicon layer 64 is formed. Translucent electrodes 65 a and 65 b are formed on the p-type amorphous silicon layer 63 and the n-type amorphous silicon layer 64. A collecting electrode 66a is formed on the translucent electrode 65a, and a collecting electrode 66b is formed on the translucent electrode 65b. The collecting electrode 66 a is a thin line-shaped electrode formed on the surface of the light receiving surface 6 A of the solar battery cell 6, and the collecting electrode 66 b is an electrode formed on the entire surface of the back surface 6 B of the solar battery cell 6. The collector electrodes 66a and 66b can be formed on both surfaces of the n-type single crystal silicon substrate 61 by printing a metal paste in which metal fine particles such as silver or copper and a resin are mixed, and film formation such as vapor deposition and sputtering. The current generated in the surface of the n-type single crystal silicon substrate 61 is collected by technology, plating, or the like. The current collecting electrode 66a is preferably a grid pattern in which fine lines extending in a straight line are arranged in parallel at intervals as shown in the figure, but may be a mesh pattern or a dendritic pattern. The collector electrode 66a is sometimes called a grid electrode or a finger electrode because of its shape.

  As shown in FIG. 1B, the n-type single crystal silicon substrate 61 has fine irregularities for preventing reflection on both surfaces. In the drawing, both surfaces of the n-type single crystal silicon substrate 61 are uneven, but a flat layer may be formed on the back side, or both sides may be flat.

Then, the function and effect of the solar cell module of this Embodiment are demonstrated. First, in FIG. 1, the incident light L ₁ entering the inter-cell region passes through the translucent substrate 5 and enters the wavelength conversion layer 2. Of this light, light in a specific wavelength region that is wavelength-converted (for example, ultraviolet light having a wavelength of 300 nm to 400 nm) is absorbed by the phosphor particles 2b and emitted as fluorescence L ₂ having a longer wavelength (for example, wavelength 500 nm). . When a single crystal Si heterojunction cell is used as the solar battery cell 6, the quantum efficiency is 20% or less for light having a wavelength of 300 nm, whereas it is 80% or more for light having a wavelength of 500 nm. By thus converting the wavelength of ultraviolet light, the power generation efficiency due to the light incident on the inter-cell area R _I can be greatly improved.

  Moreover, the sealing material which has ethylene-vinyl acetate copolymer (EVA) as a main component is used for the majority of the solar cell modules marketed. Such a sealing material is often added with an ultraviolet light absorbing agent in order to prevent the ultraviolet light deterioration of EVA. Therefore, EVA has a very low transmittance for light having a wavelength of 400 nm or less, and the transmittance is almost 0% for light having a wavelength of 300 nm.

On the other hand, when silicone is used as the base material 2a of the wavelength conversion layer 2, the transmittance of silicone shows a high transmittance of about 90% even for light with a wavelength of 300 nm. Thus, by forming the wavelength conversion layer 2 to the inter-cell area R _I, conventionally possible to reach the cell after having converted to a wavelength suitable for generating ultraviolet light that has been absorbed by the sealing material It becomes. Thereby, the incident light to the photovoltaic cell 6 increases, and the power generation efficiency of the photovoltaic module 1 is improved.

  For example, assuming that the area where the solar battery cell 6 does not exist in the solar battery module is 16% of the whole, and assuming that light having a wavelength of 300 to 400 nm incident on this region is converted to light of 500 nm, about 0.3 points. Conversion efficiency can be expected.

The behavior of light inside the wavelength conversion layer 2 is schematically shown in FIG. As described above, light having a short wavelength out of light incident on the wavelength conversion layer 2 is absorbed by the phosphor and emitted as light having a longer wavelength (fluorescence L ₂ ). At this time, the phosphor particles 2b regardless of the incident direction of light, it is emitted toward the fluorescent L ₂ in all directions. The light emitted perpendicularly to the bottom surface of the wavelength conversion layer 2 passes through the bottom surface of the wavelength conversion layer 2 and enters the back sheet 8 through the sealing material 4. A part of the light reflected by the back sheet 8 is totally reflected by the translucent substrate 5 and enters the solar battery cell 6 (indirect incident light).

On the other hand, of the light emitted from the phosphor particles 2b, the light emitted at an angle greater than the critical angle repeats total reflection inside the wavelength conversion layer 2 as shown by the arrow in FIG. 2, and about 70 to 80% is in the end face 2T direction. It is focused on. Desirably, if the normal line passing through the center of the end face 2T passes through the center of the light receiving surface 6A of the solar battery cell 6, more light can be collected. From the end face condensing of the wavelength conversion layer 2, by inclining the end face 2T to face in the direction of the solar cell 6, actively direction of the solar cell 6 light incident on the inter-cell area R _I It is possible to collect light. As a result, the optical path length to the cell can be reduced to one third or less as compared with the conventional indirect incident light.

In addition, when Lumogen F Violet 570 is used as a phosphor, its maximum quantum efficiency (in CH ₂ Cl ₂ ) is 94%, so that light loss associated with wavelength conversion in the phosphor is about 10% or less. . On the other hand, the transmission / absorption loss due to the backsheet 8 is about 10%, which is equal to or greater than the light absorption / loss due to the phosphor.

Than is reflected by the back sheet 8 light incident on the inter-cell area R _I For the above reasons, it can significantly reduce the light loss by employing the structure of the first embodiment utilizing a wavelength conversion layer 2 is there. The remarkable effect of the solar cell module of the present embodiment is that, by introducing the wavelength conversion layer 2 whose end face 2T is inclined in this way, the traveling direction of light can be controlled in addition to the wavelength conversion effect. .

  As described above, by using the module structure of the present invention, the wavelength conversion action and the light collection action act as a synergistic effect, which is very effective in improving the power generation efficiency of the solar cell module.

Further, when the ultraviolet light reaches the back sheet 8, deterioration such as yellowing of the sheet occurs, which causes a decrease in module power generation performance. However it is possible to reduce the ultraviolet light irradiated to the back sheet 8 by the ultraviolet light in the cell between the regions R _I as the solar cell module 1 of this embodiment is provided a wavelength conversion layer 2 which converts the visible light . This contributes to extending the life of the solar cell module 1. Alternatively, the module manufacturing cost can be reduced because the backsheet 8 does not need to be resistant to ultraviolet light.

  As described above, this embodiment is effective not only for improving the efficiency of the solar cell module but also for extending the life.

  Next, a method for manufacturing the solar cell module according to Embodiment 1 will be described. First, the solar cells 6 are connected by the interconnector 7. For the connection of the interconnector 7, low melting point solder or the like is used. Note that the interconnector 7 that connects two adjacent solar cells 6 ensures electrical continuity by connecting the interconnector 7 and the bus electrode that is arranged perpendicular to the current collecting electrode 66a on the solar cell. doing. Next, as shown in an exploded perspective view before the lamination step in FIG. 4, the light-transmitting substrate 5 made of a glass plate, the light-receiving surface side sealing material 4 a including the wavelength conversion layer 2, and the interconnector 7 are connected to each other. The solar battery cell 6, the back surface side sealing material 4b, and the back film 8 are stacked in order, and the sealing process of heating and pressing in vacuum is performed. The light receiving surface side sealing material 4a and the back surface side sealing material 4b are melted to fill a gap between the light receiving surface side translucent substrate 5 and the back surface side back film 8, thereby fixing the solar cells 6. . In this way, the solar cell module 1 shown in FIG. 1A is completed.

  This will be described in detail below. The manufacturing method of the wavelength conversion layer 2 is shown below. First, as shown in FIG. 3A, a light receiving surface side sealing material 4a having a concave structure corresponding to a desired shape of the wavelength conversion layer 2 is formed. The concave structure is produced as a sheet having a concave structure in advance by physically cutting a sheet-like sealing material or using a melt extrusion molding method or an extrusion laminating method. The light-receiving surface side sealing material 4a is a thermoplastic resin or a thermosetting translucent resin capable of sealing the solar battery cells 6, and preferably has a thickness of 0.1 to 1 mm and a melting point of 100 to 180 ° C. As such a material, for example, a sealing material mainly composed of EVA, polyvinyl butyral (PVB), ionomer, polyolefin, or the like can be used.

  Subsequently, the phosphor particles 2b are dispersed in a base material 2a made of a liquid or gel-like translucent resin material. In order to arrange the manufacturing process as much as possible, the thermosetting temperature is preferably equal to or less than that of the light-receiving surface side sealing material 4a used for the module. For example, a silicone resin can be used as the gel material that becomes the base material 2a for dispersing the phosphor particles 2b. Further, in order to uniformly disperse the phosphor particles 2b in the base material 2a, the phosphor particles 2b are previously dispersed in a volatile organic solvent such as acetone, ethanol, and toluene, and then mixed with the base material 2a. It doesn't matter. However, the organic solvent to be used must be a material that does not hinder the thermosetting of the base material 2a.

  When Lumogen F Violet 570 is used as the phosphor particles 2b and a silicone resin is used as the base material 2a, the amount of the phosphor particles 2b is preferably 0.01 to 0.05% with respect to the weight ratio of silicone. If a concentration higher than this is added, the influence of multiple absorption that absorbs the light emitted from the phosphor particles 2b again becomes stronger, and the transmittance decreases.

  Subsequently, as shown in FIG. 3 (b), the gel-like resin 2G in which the phosphor is dispersed is poured into the concave portion of the sheet-like light-receiving surface side sealing material 4a having a concave structure, and superheated while vacuum degassing. By doing so, the resin is temporarily cured. By temporary curing, even if the temperature rises again, it does not flow. Thus, the wavelength conversion sealing material 3 having a sheet-like wavelength conversion function in which the wavelength conversion layer 2 and the light receiving surface side sealing material 4a are integrated can be produced. Using this wavelength conversion sealing material 3, as shown in an exploded perspective view in FIG. 4, a stacked body is formed, and the solar cells 6 are sealed with a laminator to manufacture a wavelength conversion type solar cell module. be able to. Here, the translucent substrate 5, the sheet-like wavelength conversion encapsulant 3, the solar cells 6 interconnected by the interconnector 7, the back-side encapsulant 4b, and the back sheet 8 are sequentially laminated.

  As a modification of the above method, the gel resin may not be poured into the concave structure of the light receiving surface side sealing material 4a at a time. It is possible to form a phosphor concentration gradient in the wavelength conversion layer by repeating the procedure of pouring a desired amount of resin material into the recess, preliminarily curing by heating, and pouring the resin material with the phosphor concentration changed. Is possible. In addition, when using a relatively high density phosphor such as a rare earth metal complex as a wavelength conversion agent, the phosphor sinks to the bottom of the wavelength conversion layer due to the influence of gravity, and the phosphor concentration in the wavelength conversion layer is not uniform. There is a possibility. However, by flowing the gel material into the concave structure in a plurality of times as described above, the influence of such deposition on the bottom of the phosphor can be mitigated.

  According to the above method, by using the sheet-like wavelength conversion sealing material 3 in which the wavelength conversion layer 2 and the light receiving surface side sealing material 4a are integrated, a sealing method using a conventional laminator can be applied as it is. Become. Therefore, this production method is a low cost and excellent mass productivity method.

  The cross-sectional structure of the wavelength conversion layer 2 is not limited to a trapezoidal shape. For example, as shown in a modification in FIG. 5, only a part of the surface in the thickness direction of the wavelength conversion layer 2 is inclined, and the inclined end surface 2TS is formed. It may be configured. Further, as shown in FIG. 6 as another modification, the shape of the end surface may constitute a convex curved surface 2TR.

  In addition, the width of the light receiving surface of the wavelength conversion layer 2 may not be the same as the width of the inter-cell region, and may be smaller than the width of the inter-cell region or may have a structure protruding on the cell. Furthermore, the wavelength conversion layer 2 may not be in contact with the translucent substrate 5, but the wavelength conversion layer 2 and the translucent substrate 5 must be in contact with each other in order to eliminate the influence of absorption by the sealing material. Is desirable.

Embodiment 2. FIG.
Next, a solar cell module and a manufacturing method thereof according to Embodiment 2 of the present invention will be described. In the present embodiment, as shown in FIG. 7, the wavelength conversion layer 2 is further brought into contact with a low refractive index sealing material 4l having a lower refractive index than the base material 2a in a region corresponding to the inter-cell region. It is characterized by that. About another part, it is the same as that of the solar cell module of the said Embodiment 1, and abbreviate | omits description here. The same symbols are assigned to the same parts.

  In the module structure of the present embodiment, as shown in FIG. 7, a high refractive index sealing material 4 h is disposed in a region in contact with the inclined end surface 2 T of the wavelength conversion layer 2 and in contact with the light receiving surface 6 A of the solar battery cell 6. . In the region not involved in the wavelength conversion, the refractive index of the high refractive index sealing material 4h is larger than the refractive index of the resin material that is the base material 2a of the wavelength conversion layer 2, and is the outermost surface layer on the light receiving surface 6A side of the solar battery cell 6. The refractive index of the translucent conductive film constituting the antireflection layer or translucent electrode 65a is smaller. By making the refractive index of the sealing material in contact with the end face 2T of the wavelength conversion layer 2 larger than that of the base material of the wavelength conversion layer, the interface reflectance can be reduced. Furthermore, the reflectance at the cell / sealing material interface can be reduced by making the refractive index of the high refractive index sealing material 4h smaller than the refractive index of the cell outermost layer.

  For example, silicone having a refractive index of 1.5 is used as a resin material constituting the base material 2a of the wavelength conversion layer 2, and a transparent electrode 65a made of a transparent conductive film having a refractive index of 2.0 is formed on the cell surface. In this case, the refractive index of the high-refractive-index sealing material 4h is preferably about 1.75, which is an intermediate between them. Further, as a method for controlling the refractive index of the sealing material, a method of dispersing an inorganic filler powder material such as titanium oxide or zinc oxide in a liquid translucent resin can be given. Further, a low refractive index sealing material 41 (back surface side sealing material) may be formed in a region in contact with the bottom surface of the wavelength conversion layer 2 and not in contact with the light receiving surface 6A of the solar battery cell 6. As the material of the low refractive index sealing material 4l, a material having a refractive index smaller than that of the resin material that is the base material 2a of the wavelength conversion layer 2 is used. With this structure, the interface reflectance at the bottom surface of the wavelength conversion layer 2 can be increased and light can be confined in the wavelength conversion layer 2.

  With the above structure, the end face condensing function of the wavelength conversion layer 2 can be improved. That is, the solar cell 6 is obtained by increasing the interface reflectance at the bottom surface of the wavelength conversion layer 2 and reducing the interface reflectance at the end surface 2T even for light having a wavelength that is not subjected to the wavelength conversion action by the phosphor. Improve the light condensing effect. Furthermore, since the refractive index of the sealing material in contact with the solar battery cell 6 is increased, the cell / sealing material interface reflectance can be reduced. With the above effect, there is an advantage that the amount of light incident on the cell can be increased and the power generation efficiency of the module can be improved.

  Hereinafter, an example of the sealing process in the manufacturing method of a solar cell module is demonstrated in detail. First, as shown in FIG. 8A, a low-refractive index sealing material 4l having a concave structure is prepared in a region where solar cells 6 are arranged. The concave structure can be manufactured by the same method as shown in the first embodiment. Next, as shown in FIG. 8B, only the back surface 6B of the solar battery cell 6 is sealed with a laminator using the low refractive index sealing material 4l and the back sheet 8. At this time, the surface of the solar battery cell 6 may be covered with a protective film 17 in order to protect the cell surface. The protective film 17 may be any material that protects the solar battery cell 6 and can be peeled off from the sealing material after lamination. For example, a Teflon (registered trademark) sheet can be used. This is referred to as a back surface sealing module Sb.

  Subsequently, as shown in FIG. 8C, the light receiving surface side sheet Sa in which the high refractive index sealing material 4h and the wavelength conversion layer 2 are integrated is used as the light receiving surface side sealing material in the first embodiment (FIG. 3). ). Further, the bottom of the wavelength conversion layer 2 of the light receiving surface side sheet is cut as shown in FIG. This is the light-receiving surface side sheet Sa.

  Finally, as shown in FIG. 8E, the back surface sealing module is sealed with a laminator using the light receiving surface side sheet 13 and the translucent substrate 5. Thus, the solar cell module 1 shown in FIG. 7 can be manufactured by dividing the sealing of the cell front and back into two stages.

  As described above, by using the sheet-like wavelength conversion sealing material in which the wavelength conversion layer and the sealing material are integrated, the cells can be sealed without changing the conventional laminating process. Therefore, this method is a low cost and excellent mass productivity method.

  As described above, according to the present embodiment, the interface reflectance at the interface between the end face 2T of the wavelength conversion layer 2 and the sealing material can be reduced, and the light is condensed on the end face 2T of the wavelength conversion layer 2. Can efficiently reach the solar battery cell 6. This has the advantage that the amount of light incident on the cell can be increased and the power generation efficiency of the module can be improved.

Embodiment 3 FIG.
Next, a solar cell module according to Embodiment 3 of the present invention will be described. In the present embodiment, in the solar cell module shown in the second embodiment, as shown in FIG. 9, the phosphor particles 4r having a wavelength conversion function are dispersed in the high refractive index sealing material 4h to obtain the second wavelength. The conversion layer 14 is assumed. That is, in the present embodiment, the wavelength conversion layer is constituted by a two-layer structure including the first wavelength conversion layer 2 and the second wavelength conversion layer 14. Here, since the first wavelength conversion layer 2 has the same configuration as the wavelength conversion layer used in the first embodiment, the same reference numerals are used here. The phosphor particles 4r of the second wavelength conversion layer 14 absorb longer wavelength light than the phosphor particles 2b included in the first wavelength conversion layer 2, and further convert the absorbed light to the longer wavelength side. It is characterized by having. For example, it is assumed that Lumogen F Violet 570 is used for the first wavelength conversion layer 2 and Lumogen F Yellow 083 (BASF) whose wavelength conversion region is on the longer wavelength side is used for the second wavelength conversion layer 14. As a result, the ultraviolet light incident between the cells is first wavelength-converted by the first wavelength conversion layer 2. Further, this light is condensed on the end face of the second wavelength conversion layer 14 and is incident on the second wavelength conversion layer 14. Here, the wavelength is converted again and enters the solar battery cell 6. About another part, it is the same as that of the solar cell module of the said Embodiment 1, and abbreviate | omits description here. The same symbols are assigned to the same parts.

  As described above, the incident light can be adjusted to a wavelength region where the spectral sensitivity of the solar battery cell is high by using the multilayer structure of the wavelength conversion layer. Thereby, the conversion efficiency of a solar cell module can be improved.

Embodiment 4 FIG.
Next, a solar cell module according to Embodiment 4 of the present invention will be described. In the present embodiment, the solar cell module shown in Embodiment 1 is made of aluminum having a function of reflecting light to the interface between the bottom surface of the wavelength conversion layer 2 and the sealing material 4 as shown in FIG. A reflection plate 13 is provided. About another part, it is the same as that of the solar cell module of the said Embodiment 1, and abbreviate | omits description here. The same symbols are assigned to the same parts.

  In manufacturing, as shown in FIGS. 11A to 11C, a concave structure corresponding to the shape of the desired wavelength conversion layer 2 is formed in the same manner as shown in FIG. 3A in the first embodiment. The light-receiving surface sealing material 4a is formed (FIG. 11A). Then, the reflecting plate 13 is formed by sticking an aluminum tape to a region to be the bottom surface of the sealing material having the concave structure (FIG. 11B). Alternatively, the reflective film may be formed by a technique such as vapor deposition of a highly reflective metal such as aluminum or silver on the bottom surface of the light receiving surface side sealing material 4a having a concave structure, or applying a white paint. Thereafter, in the same manner as in the first embodiment, the gel-like resin 2G in which the phosphor is dispersed in the concave portion of the sheet-like light-receiving surface side sealing material 4a in which the concave structure is formed as shown in FIG. The resin is temporarily cured by pouring and heating while vacuum degassing. By temporary curing, even if the temperature rises again, it does not flow. In this manner, a sheet-like wavelength conversion sealing material 3 in which the wavelength conversion layer 2 and the light receiving surface side sealing material 4a are integrated can be produced. A wavelength conversion type solar cell module can be manufactured by forming a stack using the wavelength conversion sealing material 3 and sealing the solar cells 6 with a laminator. Here, the translucent substrate 5, the sheet-like wavelength conversion sealing material 3, the solar cell 6 interconnected by the interconnector 7, the back surface side sealing material 4b, and the back sheet 8 are sequentially laminated.

  With the above structure, the effect of confining the light that has reached the bottom surface of the wavelength conversion layer 2 due to the presence of the reflector 13 inside the layer is increased. In particular, the effect of condensing light having a wavelength not involved in wavelength conversion on the end face is significantly improved. Due to this effect, loss of long-wavelength light mainly in the sealing material or the back sheet can be reduced, so that the amount of light incident on the cell is increased and the conversion efficiency of the solar cell module is improved.

  In addition, since the light applied to the back sheet 8 can be completely blocked, the back sheet 8 can be prevented from being deteriorated by ultraviolet light, thereby contributing to the extension of the module life and the cost reduction of the back sheet 8.

  This reflector can be applied not only to the solar cell module of the first embodiment but also to the solar cell modules of the second and third embodiments.

Embodiment 5.
In the wavelength conversion type solar cell module 1 shown in the first to fourth embodiments, the reflection plate 23 is formed at the interface between the frame and the edge of the wavelength conversion layer formed on the outer periphery of the module as shown in FIG. It is provided with. Although not shown, a buffer material is provided on the inner wall of the frame, and a reflection plate 23 is provided on the end face of the outer peripheral portion of the wavelength conversion layer in contact with the buffer material of the frame 20. As in the fourth embodiment, the reflector can be formed by attaching an aluminum tape or a mirror, or using a white paint or a white adhesive.

  The light incident on the wavelength conversion layer 2 repeats total reflection as shown in FIG. 2 and is guided in the horizontal direction of the module. Due to this action, a part of the incident light is guided to the outer periphery of the module and enters the buffer material at the interface between the frame and the module. In general, a material having low reflectance such as black rubber is used for the buffer material, so that the light condensed in the end face direction is absorbed by the buffer material and does not contribute to power generation. Therefore, by forming a reflector on the outer periphery of the wavelength conversion layer, the light collected on the outer periphery can be reflected and guided in the cell direction. This effect increases the amount of light incident on the cell and increases the amount of generated current of the solar cell module.

  Also in the conventional solar cell module, a part of incident light reaches the module outer periphery through reflection on the back sheet and glass. However, since the wavelength conversion layer is used as a waveguide in the present embodiment, the amount of light reaching the outer periphery of the module is increased as compared with the conventional module. For the above reason, the effect produced by forming the reflector on the outer periphery of the module becomes more remarkable when combined with the wavelength conversion layer.

Embodiment 6.
In this embodiment, the wavelength conversion layer 52 in which the end face is inclined to form a cell between the regions R _I of the transparent substrate 51 as shown in FIG. 13, characterized in that the light receiving surface side sheet 50 of this . As the translucent substrate 51, a glass plate, a translucent resin film, an acrylic plate, or the like can be used.

  A method for manufacturing the wavelength conversion layer is shown in FIG. First, the end surface of the translucent resin film 52a in which the phosphor particles 52b are dispersed is cut obliquely. Next, this material does not contain a phosphor, and a transparent substrate 51 made of a resin substrate manufactured so as to correspond to the end face shape of the wavelength conversion layer is bonded with an optical adhesive or the like. Heat and melt with to stick together. Thereby, a wavelength conversion layer and a translucent board | substrate can be integrated.

When the wavelength conversion layer is formed on a part of the sealing material as in the first embodiment, a part of the ultraviolet light is absorbed by the translucent substrate 5. Meanwhile, in the present embodiment has the advantage that for comprising a wavelength converting layer in the cell between the regions R _I of the transparent substrate 51, the loss of ultraviolet light is reduced wavelength convertible amount increases. In this example, the translucent substrate may be formed of a glass substrate, and the translucent resin film may be formed of a translucent glass substrate.

Embodiment 7.
In this embodiment, wherein the end face is formed in a matrix in the inter-cell area R _I of the wavelength conversion sealing material 3 as shown in FIG. 15 the wavelength conversion layer 2 which is inclined. About another part, it is the same as that of the solar cell module of the said Embodiment 1, and abbreviate | omits description here. The same symbols are assigned to the same parts.

  According to such a configuration, there is an advantage that more light can be taken into the wavelength conversion layer 2 and the amount of light that can be wavelength-converted is increased, but there is a possibility that part of the light directly incident on the solar cell is blocked. is there.

Embodiment 8.
In this embodiment, characterized by being formed in an island shape in the intercell region R _I of the wavelength conversion sealing material 3 as a wavelength conversion layer 2 which end surface is inclined in Figure 16. About another part, it is the same as that of the solar cell module of the said Embodiment 1, and abbreviate | omits description here. The same symbols are assigned to the same parts.

  According to such a configuration, the amount of light taken into the wavelength conversion layer 2 is reduced and the amount of light that can be converted is reduced, but the probability that light directly incident on the solar cell is shielded is reduced.

In addition, as shown in FIG. 17, a main part enlarged schematic diagram, the shape of each solar battery cell 6 in the solar battery module is often an octagonal shape by using the corner 6 </ b> M as a chamfer. In this case, the wavelength conversion layer 2 formed in an island shape in the inter-cell region R _I has a shape having a slight overlap portion along the outer shape of the solar battery cell 6 as indicated by a broken line. It is desirable to be formed. That is, it is desirable that the wavelength conversion layer 2 formed in an island shape is formed so as to have a polygonal shape formed by the corners 6M that are close to each other among the corners 6M of four adjacent cells.

  In addition, each element included in each of the above-described embodiments can be combined as much as technically possible, and a combination of these is also included in the scope of the embodiment as long as it includes the features of the embodiment. In addition, various modifications may be conceived by those skilled in the art within the scope of the idea of the embodiments, and these modifications are also within the scope of the embodiments.

  For example, when the problems described in the column of problems to be solved by the invention can be solved even if some structural requirements are deleted from all the structural requirements shown in the first to eighth embodiments or the respective embodiments. The configuration from which this configuration requirement is deleted can be extracted as an invention. Furthermore, the constituent elements from the first embodiment to the eighth embodiment may be appropriately combined.

  Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Solar cell module, 2 wavelength conversion layer (1st wavelength conversion layer), 2a base material, 2b phosphor particle, 2T end surface, 3 wavelength conversion sealing material, 4 sealing material, 4a light-receiving surface side sealing material, 4b back-surface-side sealing member, 5 light-transmissive substrate, 6 solar cell, 6A-receiving surface, 6B backside, 6M corner, 7 interconnector, 8 backsheet, L ₁ incident light, L ₂ fluorescence, 13 reflector, 4l low refractive index encapsulant, 4h high refractive index sealing member, 14 second wavelength conversion layer, 17 protective film, 20 frames, 23 reflector, between R _I cell region.

Claims (10)

A plurality of solar cells,
A light-receiving surface side sealing material covering the light-receiving surface of the solar battery cell;
A solar cell module comprising a back surface side sealing material covering a back surface side which is a surface facing the light receiving surface of the solar cell, and being integrally sealed,
The light-receiving surface side sealing material is
Arranged in the inter-cell region of the adjacent solar cells,
A wavelength conversion layer having an inclined end face formed obliquely so as to face the light receiving surface of the solar battery cell;
A solar cell module comprising: a light receiving surface side sealing layer that contacts the wavelength conversion layer and contacts the light receiving surface side of the solar battery cell.   2. The solar cell module according to claim 1, wherein a normal line passing through a center of the inclined end surface of the wavelength conversion layer passes through a center of the light receiving surface of the solar cell. The wavelength conversion layer is composed of a base material made of a thermoplastic resin and functional particles having a wavelength conversion function,
The solar cell module according to claim 1 or 2, wherein the light-receiving surface side sealing layer has a high refractive index sealing material adjacent to the wavelength conversion layer and having a higher refractive index than the base material. .   4. The solar cell module according to claim 3, wherein the light-receiving surface side sealing layer is smaller than a refractive index of an antireflection film or a translucent conductive film constituting the outermost surface layer of the solar battery cell.   5. The wavelength conversion layer according to claim 1, wherein the wavelength conversion layer is in contact with a low refractive index sealing material having a lower refractive index than the base material in a region corresponding to the inter-cell region. The solar cell module according to.   In the inter-cell region, the wavelength conversion layer is in contact with the first wavelength conversion layer in contact with the light receiving surface support plate in the first base material, the first wavelength conversion layer, and the first base material. The phosphor particles are dispersed in a second base material having a higher refractive index than the material, and the second wavelength conversion layer has a light emission wavelength larger than that of the first wavelength conversion layer. The solar cell module of any one of Claim 2 to 5.   The solar cell module according to any one of claims 1 to 6, wherein the wavelength conversion layer includes a reflecting plate or a reflecting film that reflects light on a bottom surface.   The solar cell module according to any one of claims 1 to 7, wherein the solar cell module includes a reflector at an interface between a frame that covers a peripheral edge and an end of the wavelength conversion layer. A plurality of solar cells,
A translucent substrate;
A light-receiving surface side sealing material covering the light-receiving surface of the solar battery cell;
A back side sealing material covering the back side which is a surface facing the light receiving surface of the solar battery cell;
A solar cell module comprising a backsheet and integrally sealed,
The translucent substrate is
Arranged in the inter-cell region of the adjacent solar cells,
A solar cell module comprising a wavelength conversion layer having an inclined end surface formed obliquely so as to face the light receiving surface of the solar cell. A sheet-shaped light-receiving surface side sealing having a wavelength conversion layer having an inclined end surface by pouring a liquid or gel-like resin material in which phosphor particles are dispersed into a light-receiving surface side sealing material on a sheet having a concave structure Forming a material;
Sandwiching the solar battery cell between the light receiving surface side sealing material and the back surface side sealing material so that the inclined end face faces the light receiving surface of the solar battery cell, and forming a stack,
Heating and pressurizing the stack and laminating;
The manufacturing method of the solar cell module characterized by including.

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