JP2014179513A - Solar battery module and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solar battery module for improving power generation efficiency by efficiently increasing a light amount radiated to a light receiving surface of a solar battery cell.SOLUTION: A solar battery module comprises: a plurality of solar battery cells 3 arranged in arrays and connected by lead wire; a resin sealing layer composed of light receiving surface side sealing material 2 and back surface side sealing material 5; a translucent substrates 1 stacked on the light receiving surface side of the resin sealing layer; and a back sheet 6 stacked on the back surface side of the resin sealing layer. White inorganic pigment is contained in the back surface side sealing material 5 of the light receiving surface, and is dispersed in an inter-cell region 10 of the plurality of solar battery cells 3 so that a salient part 11 is constructed on the light incident side rather than the light receiving surface of the solar battery cell 3.

Description

  The present invention relates to a solar battery module and a method for manufacturing the same, and in particular, in a solar battery module in which a plurality of solar battery cells are resin-sealed, particularly, the light incident on the gap between the solar battery cell and the solar battery cell is effectively used. This relates to a structure that increases power generation efficiency.

  Solar cells using crystalline silicon as a substrate are generally produced with a thickness of 0.1 mm to 0.3 mm and are vulnerable to physical impact. Therefore, in the solar cell module, a light-transmitting substrate such as glass is disposed on the light-receiving surface side for buffering physical impact on the solar cell, and sealed on the light-receiving surface side and the back surface side of the solar cell. Stop material is filled. Usually, a light receiving surface side sealing material having a thickness of 0.4 mm to 1.0 mm is provided on the light receiving surface side of the solar battery cell, and a back surface side sealing material having a thickness of 0.4 mm to 1.0 mm is provided on the back surface side. A back sheet is further provided on the back side of the back side sealing material in order to maintain insulation.

  In a solar cell module, solar cells are connected in series with lead wires, so that a plurality of solar cells arranged side by side and the solar cells have a gap of 2 mm to 4 mm for routing the lead wires. . The light irradiated to other than the solar cell light receiving surface passes through this gap, is reflected by the back sheet, hits the translucent substrate, is reflected again, and is applied to the light receiving surface of the solar cell. That is, the light receiving surface side of the back sheet contains a colorant such as titanium white (titanium dioxide) so as to be scattered and reflected, and the light vertically incident on the translucent substrate in the gap portion between the solar cells is The light-transmitting substrate and the sealing material go straight and are scattered and reflected by the back sheet. The light scattered and reflected by the back sheet enters the interface between the air layer and the translucent substrate with an incident angle, and a part of the light is reflected at the interface between the air layer and the translucent substrate. Irradiates the light receiving surface of the cell. This light also contributes to power generation.

  However, since the scattering reflection surface of the back sheet is on the back side with respect to the light receiving surface of the solar battery cell, there is a problem that the component irradiated on the back surface of the solar battery cell does not contribute to power generation. On the other hand, conventionally, a coloring agent such as titanium white (titanium dioxide) is added to the sealing material on the back side of the solar battery cell in order to effectively use the light incident on the gap between the solar battery cell. And the technique which forms a scattering reflection surface in the same plane as the light-receiving surface of a photovoltaic cell is also disclosed (for example, patent document 1). With this configuration, it is said that the light use efficiency is increased and the power generation efficiency of the solar cell is improved.

  In addition, the refractive index is different from that of the light-transmitting substrate or the resin sealing layer between the light-transmitting substrate and the resin sealing layer in the gap portion between adjacent solar cells, and the cross section is convex on the back surface side. A technique for forming a refractive layer is also disclosed (for example, Patent Document 2). With this configuration, it is supposed that the effect of refracting the light incident on the gap portion and directly guiding it to the light receiving surface of the solar battery cell can be obtained.

  In addition, in order to suppress misalignment and cell cracking during lamination of the solar cell module, the solar cell module sealing material provided with a positioning recess in the region corresponding to the cell region in the back surface side sealing material Have also been studied (for example, Patent Document 3). Further, this Patent Document 3 also describes that the back side sealing material may be colored white or the like in accordance with the surrounding installation environment.

JP 2012-004146 A JP 2011-029273 A JP 2005-236217 A

  However, according to the technique of the above-mentioned conventional Patent Document 1, the light incident on the gap between the solar cells does not directly enter the light receiving surface of the solar cells, but from the interface between the translucent substrate and the air. Only the reflected light contributes to power generation. Here, the scattered light on the surface of the sealing material on the back surface side of the solar battery cell has a relatively large amount of reflection component having a reflection angle near 0 °. Since the reflectivity at the interface depends on the incident angle as well as the refractive index difference, a lot of light is not reflected at the interface between the translucent substrate and the air, but is emitted to the outside. The efficiency was low and it was not sufficient in improving the power generation efficiency.

  On the other hand, according to the technique of Patent Document 2, a part of the light incident on the gap between the solar cells is directly incident on the light receiving surface of the solar cells, but is refracted by the translucent substrate and the refractive index layer. Since there is a difference in rate, incident light is reflected at the interface, travels straight again, and is emitted to the outside of the translucent substrate. Therefore, the utilization efficiency of light is low, and it is not sufficient in improving the power generation efficiency.

  Furthermore, if the sealing material for solar cell modules which provided the recessed part in the part equivalent to a cell area | region for the purpose of positioning and cell crack suppression like patent document 3 is used, it will protrude in an inter-cell area | region as a result. The height of the convex part which becomes will become larger than the thickness of a photovoltaic cell. For this reason, the back surface side sealing material after lamination has covered a part of the light-receiving surface of a photovoltaic cell, and there existed a problem that the utilization efficiency of light fell rather. Further, when the height of the convex portion is made smaller than that of the solar battery cell, a structure similar to that of the solar battery module of Patent Document 1 is obtained, the light utilization efficiency is low, and the power generation efficiency is not sufficient.

  This invention is made | formed in view of the above, Comprising: It aims at improving the utilization efficiency of the light which injected into the clearance gap part between photovoltaic cells, and improving the electric power generation efficiency of a photovoltaic module.

  In order to solve the above-described problems and achieve the object, the present invention provides a plurality of solar cells that are connected by a translucent substrate, a light-receiving surface side sealing material, and lead wires and arranged on the same surface. And a back surface side sealing material and a back sheet are sequentially laminated and resin-sealed solar cell module, and the back surface side sealing material disposed between the back sheet and the solar cells, It is made of a material having a different refractive index so as to form a scattering interface with respect to the light receiving surface side sealing material, and the back surface side sealing material is the solar cell in the inter-cell region of the plurality of solar cells. It projects from the light receiving surface to the light incident side.

  According to the present invention, in the gap region between the plurality of solar cells, the scattering layer is convexly formed on the light incident side with respect to the plane coincident with the light receiving surface of the solar cells, so that the incident light reflected by the scattering layer However, the component which penetrate | invades into a photovoltaic cell light-receiving surface can be obtained, without passing through the reflection of the translucent substrate surface. And since the incident angle to the translucent substrate surface can be increased, the reflectance on the translucent substrate surface can be increased, the light utilization efficiency can be increased, and the power generation efficiency is improved. Play.

1-1 is a cross-sectional view (corresponding to the AA cross section in FIG. 2-1) showing the main part of the solar cell module according to Embodiment 1 of the present invention. 1-2 is a cross-sectional view (corresponding to the BB cross section of FIG. 2-1) showing the main part of the solar cell module according to Embodiment 1 of the present invention. FIGS. 2-1 is a principal part expansion perspective view which shows the state except the sealing material of the solar cell module by Embodiment 1 of this invention. FIGS. FIG. 2-2 is a partially broken perspective view of the solar cell module according to Embodiment 1 of the present invention. FIG. 2-3 is an enlarged perspective view of the string of the solar cell module according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view illustrating the optical path of incident light between cells of the solar cell module according to Embodiment 1 of the present invention. FIGS. 4-1 is sectional drawing which shows the manufacturing process of the solar cell module of Embodiment 1 of this invention. FIGS. 4-2 is sectional drawing which shows the manufacturing process of the solar cell module of Embodiment 1 of this invention. 4-3 is sectional drawing which shows the manufacturing process of the solar cell module of Embodiment 1 of this invention. FIGS. 4-4 is sectional drawing which shows the manufacturing process of the solar cell module of Embodiment 1 of this invention. FIG. 5 is a cross-sectional view showing the manufacturing process of the solar cell module according to Embodiment 2 of the present invention. FIG. 6 is a cross-sectional view showing a manufacturing process for the solar cell module according to Embodiment 3 of the present invention. FIG. 7: is sectional drawing which shows the manufacturing process of the solar cell module of Embodiment 4 of this invention. FIG. 8 is a cross-sectional view showing the solar cell module according to Embodiment 5 of the present invention. FIG. 9 is a cross-sectional view showing a manufacturing process for the solar cell module according to Embodiment 5 of the present invention. FIG. 10 is an essential part enlarged perspective view showing a state in which the sealing material of the solar cell module according to Embodiment 6 of the present invention is removed. FIG. 11: is a principal part expansion perspective view which shows the state except the sealing material of the solar cell module by Embodiment 7 of this invention. FIG. 12 is a main part enlarged perspective view showing a state in which the sealing material of the solar cell module according to Embodiment 8 of the present invention is removed. FIG. 13 is a cross-sectional view showing a solar cell module of Comparative Example 1 shown for comparison of light paths. FIG. 14 is a cross-sectional view showing a solar cell module of Comparative Example 2 shown for comparison of light paths.

  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. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. 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.

Embodiment 1 FIG.
FIGS. 1-1 and 1-2 are sectional views of the vicinity of the inter-cell region of the solar cell module according to Embodiment 1 of the present invention. FIG. 1-1 is a cross-sectional view that does not include the lead wire 4, and FIG. 1-2 is a cross-sectional view that includes the lead wire 4. FIGS. 2-1 to 2-3 are views showing the main part of the solar cell module according to Embodiment 1 of the present invention. FIG. 2-1 is a main part enlarged perspective view showing a state in which the sealing material of the solar cell module is removed, FIG. 2-2 is a partially broken perspective view of the solar cell module, and FIG. It is a perspective view. FIGS. 1-1 and 1-2 correspond to the AA cross section and the BB cross section of FIG. In FIGS. 1-1 and 1-2, the solar cell module 50 includes a light-transmitting substrate 1 made of a light-transmitting material such as glass and a light-receiving surface-side sealing material 2 made of a light-transmitting resin from the light receiving surface side. And the some photovoltaic cell 3, the back surface side sealing material 5, and the back sheet 6 excellent in the weather resistance are laminated | stacked and comprised in this order. The back surface side sealing material 5 is made of a material having a higher refractive index than that of the light receiving surface side sealing material 2, and the inter-cell region 10 protrudes from the light receiving surface of the solar battery cell 3 to the light incident side. And That is, the back surface side sealing material 5 forms a convex portion 11 protruding from the solar battery cell 3 in the inter-cell region 10, enters the inter-cell region 10, and the convex portion 11 of the back surface side sealing material 5 The light reflected at the interface is guided to the solar battery cell 3. Here, as shown in FIG. 2A, the plurality of solar cells 3 are connected in series by five lead wires 4 to form a string S, and three such strings S are juxtaposed to form a matrix cell. Constructs an array. The solar cell 3 has a light receiving surface side electrode 3a and a back surface electrode 3b, and a lead wire 4 is connected to the light receiving surface side electrode 3a and the back surface electrode 3b by solder bonding. In addition, the light-receiving surface side sealing material 2 and the back surface side sealing material 5 are united by heat treatment, and the solar battery cell 3 is resin-sealed to form a resin sealing layer. The outer peripheral edge portion of the laminated body having such a configuration is covered with the outer frame 7 over the entire periphery, and the solar cell module 50 is manufactured as shown in a partially broken perspective view in FIG.

  In addition, as shown in FIG. 1-2, the inter-cell area | region 10 which the lead wire 4 cross | intersects the back surface sealing material 5 containing a white inorganic pigment rather than the same plane as the light-receiving surface of the photovoltaic cell 3 to the back sheet 6 side. Is arranged. And the back surface side sealing material 5 in which the white inorganic pigment is dispersed so as to be convex toward the light incident side only in the inter-cell region 10 where the lead wire 4 does not cross is formed, and a scattering interface is formed. Yes. This configuration makes it difficult for stress to be applied to the lead wires 4 and improves the reliability of the solar cell module.

  For the translucent substrate 1, a synthetic resin material such as a glass material or a polycarbonate resin is used. Further, as the glass material, white plate glass, tempered glass, heat ray reflective glass or the like is used, and generally white plate tempered glass having a thickness of about 3 mm to 4 mm is often used. On the other hand, a polycarbonate resin having a thickness of about 5 mm is often used.

  The light-receiving surface side sealing material 2 is made of a material having translucency, heat resistance, electrical insulation, and flexibility. The main component is ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), silicone resin, or the like. A synthetic resin material is preferable. And a resin-sealed layer is formed by melting and hardening a sheet-like form or a liquid form.

  The solar cells 3 are made of single crystal silicon or a polycrystalline silicon substrate having a thickness of about 0.1 mm to 0.3 mm, and are arranged in a matrix. A pn junction is formed inside the solar battery cell 3, electrodes (not shown) are provided on the light receiving surface and the back surface, and an antireflection film is provided on the light receiving surface. The lead wires 4 are sequentially connected from the light receiving surface side electrode 3a provided on the light receiving surface to the back electrode 3b provided on the back surface of the adjacent cell, thereby realizing series connection between the adjacent solar cells 3. . Moreover, in order to reflect the light which permeate | transmitted with the photovoltaic cell 3 among the light which injected into the photovoltaic cell 3, and to recycle | reuse, the reflective layer may be formed in the back surface of the photovoltaic cell.

  The lead wire 4 is made of a metal wire having a thickness of about 0.1 mm to 0.4 mm, and is appropriately formed with solder plating, a rust preventive layer, and an adhesive layer, and is electrically joined to the solar battery cell 3. The three are electrically connected. As described above, the solar cells 3 arranged in a matrix in the solar cell module 50 are sequentially connected mainly in the longitudinal direction of the solar cell module 50 to form the string S of the solar cells 3. In addition, in order to increase the generated voltage, there are some which are connected not only in the longitudinal direction but also in the short direction, and all the solar cells 3 are connected in series.

  For the back sheet 6, a material excellent in moisture permeability, weather resistance, hydrolysis resistance, and insulation is used, and a fluororesin sheet, a polyethylene terephthalate (PET) sheet on which alumina or silica is deposited, and the like are used.

  As the back surface side sealing material 5, in a gap region (inter-cell region 10) of a plurality of solar cells 3, a white inorganic pigment is dispersed so as to protrude more on the light incident side than the light receiving surface of the solar cells 3. It is desirable to do. In the inter-cell region 10, an interface between the light-receiving surface side sealing material 2 and the back surface side sealing material 5 made of materials having different refractive indexes is a scattering layer. This scattering layer is formed so as to protrude toward the light incident side from the plane that coincides with the light receiving surface of the solar battery cell 3. For this reason, the incident light 21 reflected by the scattering layer can obtain a component that enters the light receiving surface of the solar battery cell without being reflected by the surface of the light transmissive substrate, and the angle of incidence on the surface of the light transmissive substrate 1. 32 can be increased. Therefore, the light is reflected on the surface of the light-transmitting substrate 1 to become reflected light 21R, the reflectance can be increased, the light utilization efficiency can be increased, and the power generation efficiency is improved.

  Thus, the back surface side sealing material 5 is made of a material having heat resistance, electrical insulation, and flexibility in which a white inorganic pigment is dispersed. Specifically, synthetic resin materials mainly composed of ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), silicone resin, etc., and inorganic powder made of titanium white, zinc white, barium sulfate, lithopone, silica, etc. An example in which a white inorganic pigment appropriately surface-treated is dispersed is given.

  In addition, the scattering reflection characteristic of the back surface side sealing material 5 is ideal to have a high reflectance and a reflection characteristic that uniformly reflects in all directions, and it is advantageous that the content of the white inorganic pigment is large. . However, when the content of the white inorganic pigment is increased, the fluidity at the time of sealing is lowered, and the solar battery cell 3 is damaged. For example, when titanium white exceeding 30% by weight as a white inorganic pigment is mixed in ethylene vinyl acetate, cell cracking may occur near the tab line formed on the surface of the solar cell 3 due to the pressure at the time of sealing. There is a problem that the productivity of solar cell modules is lacking. Therefore, the content of the white inorganic pigment is desirably 30% by weight or less. Moreover, although the minimum of content of a white inorganic pigment cannot be set easily, when there is little content, the reflectance in the interface of the light-receiving surface side sealing material 2 and the back surface side sealing material 5 will become low. For example, when titanium white of less than 5% by weight as a white inorganic pigment is mixed in ethylene vinyl acetate, the amount of light absorbed in the back surface side sealing material 5 with respect to reflection increases. For this reason, the effect is low if it is not contained in an amount of 5 wt% or more.

  In addition, the particle size of the white inorganic pigment needs to be sufficiently larger than the sensing wavelength of the solar battery cell because Rayleigh scattering and Mie scattering have a dominant size and are difficult to scatter backward with respect to incident light. . In general, it is necessary that the particle size is 5 times or more, specifically 5 μm or more with respect to 1 μm which is a long wavelength among the sensing wavelengths of solar cells. The same applies to the particle size of not only the white inorganic pigment but also other scattering particles such as bubbles or polymer materials.

  And in this Embodiment, the back surface side sealing material 5 makes the cross section convex to the light-receiving surface side in the inter-cell region 10, and is closer to the light-receiving surface side than the same plane as the light-receiving surface of the solar battery cell 3. It has the convex part 11 which protrudes.

  However, since the light reception is suppressed when the white inorganic pigment covers the light receiving surface of the solar battery cell 3, it is preferable that the convex portion 11 is formed only in the inter-cell region 10.

  The higher the height of the convex portion 11, the larger the solid angle between the slope of the convex portion 11 and the light receiving surface of the solar cell 3, and the more efficiently the light incident on the inter-cell region 10 is solar cell. 3 can be guided to the light receiving surface. However, if the thickness is equal to the thickness of the light-receiving surface side sealing material 2, the vicinity of the apex of the convex portion 11 is parallel to the plane having the light-receiving surface of the solar battery cell 3, and the efficiency is lowered.

  In addition, if the height of the convex portion 11 is too high, the amount of flow of the sealing material at the time of lamination increases, or the residual stress of the sealing material after processing of the concave portion of the sealing material increases. The positional deviation of the convex part 11 becomes remarkable. When we evaluated with an actual machine, it has been confirmed that if the thickness is 80% or less with respect to the thickness of the light-receiving surface side sealing material 2, no significant displacement occurs. The thickness of the light-receiving surface side sealing material 2 is preferably 80% or less.

  The convex part 11 of the back surface side sealing material 5 may be installed over almost all the inter-cell regions 10 of the solar cell module 50 as indicated by broken lines in FIG. Further, the effect of the present invention can be obtained even if it is installed only in a part of the inter-cell region 10, for example, the inter-cell region 10 avoiding the vicinity of the lead wire 4. Further, the shape of the convex portion 11 of the back surface side sealing material 5 may be a dot shape or a line shape. If it is linear, almost all of the light incident on the inter-cell region 10 can be captured. Moreover, if it is a dot form, all the surrounding surfaces of a dot will comprise a scattering surface, the contact area of the back surface side sealing material 5 and the light-receiving surface side sealing material 2 will increase, and adhesiveness will improve.

  The operation will be described based on the enlarged view of the cross section near the inter-cell region 10 shown in FIG. Incident light 20 to the inter-cell region 10 passes through the translucent substrate 1 and the light-receiving surface side sealing material 2 having substantially the same refractive index, and is closer to the light-receiving surface than the same plane as the light-receiving surface of the solar battery cell 3. It reaches the interface between the protruding convex portion 11 of the back surface side sealing material 5 and the light receiving surface side sealing material 2. A white inorganic pigment is dispersed in the back surface side sealing material 2, and the incident light 20 is diffusely reflected at this interface. In general, diffuse reflection reflects light at all angles compared to regular reflection, but the amount of light near the regular reflection component is large. Therefore, also in the case of diffuse reflection, it is important to consider the optical path of the regular reflection component in order to increase the light utilization efficiency.

  FIG. 3 shows an optical path 21 of the regular reflection component of incident light at the interface. Since the back surface side sealing material is convex toward the light receiving surface, the incident angle at the interface between the translucent substrate 1 and air is shown. 32 can be increased. As a result, the regular reflection component of the incident light can be efficiently reflected again toward the light receiving surface side of the solar battery cell 3 at the interface between the translucent substrate 1 and the air (21R). Therefore, with this structure, the incident light 20 to the inter-cell region 10 can be efficiently guided to the light receiving surface of the solar battery cell 3, and the power generation efficiency of the solar battery module 50 can be improved.

  Furthermore, since the back surface side sealing material 5 forms the convex part 11 which becomes convex on the light receiving surface side, the optical path 22 of a part of the scattered light of the incident light at the front and back surface side sealing material interface shown in FIG. As described above, a part of the scattered reflection component can be directly incident on the light receiving surface of the solar battery cell 3 only through the light receiving surface side sealing material 2. Incident light 20 entering the interspace 10 can be efficiently guided to the light receiving surface of the solar battery cell 3, and the power generation efficiency of the solar battery module 50 can be improved.

  If the protrusion amount of the convex portion 11 of the back surface side sealing material 5 with respect to the same plane as the light receiving surface of the solar battery cell 3 exceeds 0, an effect can be expected, but the slope of the convex portion 11 of the back surface side sealing material 5 The larger the solid angle between the light receiving surface of the solar battery cell 3 and the same plane, the greater the effect of introducing the incident light to the inter-cell region 10 into the solar cell light receiving surface.

  On the other hand, in the conventional solar cell module (Comparative Example 1) such as the prior art document 1, the solar cell is sandwiched and stacked between the light-receiving surface side sealing material and the back surface-side sealing material. The interface between the sealing material and the back surface side sealing material is formed between a plane that matches the light receiving surface of the solar battery cell and a plane that matches the back surface, and the light receiving surface of the translucent substrate 1 or the solar battery cell 3. The plane including the plane is translated. That is, compared with Embodiment 1, the convex part 11 is not provided in the back surface side sealing material 5 which protrudes in the light-receiving surface side rather than the same plane as the light-receiving surface of the photovoltaic cell 3.

  FIG. 13 is a cross-sectional view showing a solar cell module of Comparative Example 1 shown for comparison of light paths. The incident light 20 to the inter-cell region passes through the translucent substrate 1 and the light-receiving surface side sealing material 2 and is on a plane located on the back side of the light-receiving surface of the solar battery cell 3 as in the first embodiment. It reaches the interface between a certain back surface side sealing material 5 and the light receiving surface side sealing material 2. Since this interface is parallel to the surface of the translucent substrate 1, light incident from the vertical direction enters the back surface side sealing material 5 perpendicularly. The regular reflection component 21 which is the main reflection component is reflected again vertically and emitted to the outside, so that it does not enter the light receiving surface of the solar battery cell 3.

  Further, in a conventional solar cell module (Comparative Example 2) such as Prior Art Document 2 shown in FIG. 14, a refractive layer 15 is provided between the translucent substrate 1 and the light receiving surface side sealing material 2. Therefore, the incident light 20 to the inter-cell region 10 is refracted at the interface between the refractive layer 15 and the light-receiving surface side sealing material 2, and a part of the light is sealed on the light-receiving surface side of the solar battery cell 3. It has a component that is directly incident only through the material 2. However, there is also refracted light 24 incident on the side surface of the solar battery cell 3 and the back sheet 6. In addition, since the refractive index is greatly different between the translucent substrate 1 and the refractive layer 15 formed in the inter-cell region, the reflected light at the interface of the translucent substrate 1 out of the refracted light 24 refracted by the refractive layer 15. Since the component by 23 becomes large, is reflected again vertically, and is emitted to the outside, the component that does not enter the light receiving surface of the solar battery cell 3 increases.

  For the above reasons, the solar cell module having the structure of the first embodiment can efficiently guide the incident light in the inter-cell region to the light receiving surface of the solar cell, and can improve the power generation efficiency.

  Next, a method for manufacturing the solar cell module having the structure of the first embodiment will be described with reference to FIGS.

  In producing the sheet-shaped light-receiving surface side sealing material 2 made of a synthetic resin mainly composed of ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), silicone resin, etc., for example, the above-mentioned synthetic resin is publicly known. Ordinary extrusion molding of a composition obtained by mixing a material obtained by appropriately mixing a crosslinking agent, a crosslinking aid, an adhesion improver, an anti-aging agent and the like by a known method using a super mixer (high-speed fluid mixer), a roll mill, or the like, or It can be manufactured by a method of forming a sheet by molding by calendar molding or the like. By providing convex portions on the extrusion mold or calender molding heating roll, the light-receiving surface side sealing material 2 in which the concave portions 40 are formed as shown in FIG. Is formed and placed on the translucent substrate 1.

  Then, as shown in FIG. 4B, the solar cells 3 interconnected by the lead wires 4 are arranged so that the light receiving surface side faces the translucent substrate 1 side so as to align with the concave portion 40. Then, it is placed on the light receiving surface side sealing material 2.

  Thereafter, as shown in FIG. 4C, the sheet-like back side sealing material 5 and the back sheet 6 are sequentially placed on the solar battery cell 3. Here, as the back side sealing material, a sheet-like material made of a synthetic resin mainly composed of ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), a silicone resin, or the like in which a white inorganic pigment is dispersed is used.

  Finally, heat molding is performed while applying pressure. In the present embodiment, this step is performed by pressurizing at about 0.5 atm to 1.0 atm while heating for about 15 minutes to 1 hour at a temperature of 100 ° C. to 200 ° C. in a vacuum state with a laminator. Since the light-receiving surface side sealing material 2 and the back surface side sealing material 5 are softened and melted and crosslinked and fused, the laminate is integrated. Further, the softened and melted back surface side sealing material 5 enters the concave portion 40 of the light receiving surface side sealing material 2, and the convex portion 11 is formed in the back surface side sealing material 5 of the first embodiment. By this step, as shown in FIG. 4-4, the back surface side sealing material 5 enters the concave portion 40 of the light receiving surface side sealing material 2 to form the convex portion 11.

  Thus, the solar cell module 50 shown in FIGS. 1-1 and 1-2 is easily formed.

  In addition, what does not form the recessed part 40 as the light-receiving surface side sealing material 2 may be prepared, and the recessed part 40 may be formed by thermoforming this sheet-like light-receiving surface side sealing material 2. In the light-receiving surface side sealing material 2 in which the convex portion is provided on the heating roll and the concave portion 40 is formed, only the concave portion 40 along the long side direction can be formed. On the other hand, when forming the recessed part 40 by thermoforming the sheet-like light-receiving surface side sealing material 2, the recessed part of the light-receiving surface side sealing material 2 extended | stretched not only to the long side direction of a sheet | seat but to a short side direction. There is an advantage that 40 can be formed.

  As described above, in the method according to the present embodiment, the sheet material of the light-receiving surface side sealing material 2 prepared in advance is arranged on the translucent substrate 1 and further electrically connected by the lead wires 4. The solar cells 3 are arranged with the light receiving surface side facing the translucent substrate 1 side. Further, a sheet-like back side sealing material 5 made of a synthetic resin in which a white inorganic pigment is dispersed is disposed. Finally, the back sheet 6 is disposed on the back surface side sealing material 5. By heating the above laminated body with a laminator, the back surface side sealing material 5 penetrates into the recess 40, and therefore, the intrusion area of the back surface side sealing material 5 does not spread out from the shape of the recess 40. As assumed when the sealing material described in Technical Document 3 is used, the back surface side sealing material can be prevented from covering the light receiving surface of the solar battery cell.

  Finally, the outer frame 7 (made of a metal material such as aluminum or SUS, or a synthetic resin material) is fitted to each side of the outer periphery of the integrated laminate, and each corner is fixed to FIG. The solar cell module 50 is completed as shown in a partially broken perspective view.

  Furthermore, by making the light-receiving surface side sealing material region corresponding to the inter-cell region 10 in the vicinity of the lead wire 4 flat, stress on the lead wire 4 during lamination can be reduced, and deformation and disconnection occur. The possibility is reduced. Further, the reliability of the solar cell module 50 can be improved because the possibility of peeling between the lead wire 4 and the sealing material and disconnection of the lead wire 4 during use of the solar cell module 50 can be reduced. Can do.

Embodiment 2.
Further, as shown in the process cross-sectional view showing the state at the time of lamination (before pressure molding) in FIG. 5, the back side sealing material 5 in which the convex portion 41 is formed in the portion corresponding to the vicinity of the inter-cell region 10 is used. However, it can be manufactured similarly.

  In manufacturing, the method for forming the convex portion 41 on the back side sealing material 5 can be manufactured in the same manner as the method for forming the concave portion 40 of the light receiving surface side sealing material 2.

Embodiment 3 FIG.
Furthermore, as shown in the process cross-sectional view showing the state at the time of lamination (before pressure molding) in FIG. 6, the light-receiving surface side sealing material 2 in which the concave portion 40 is formed and the back side sealing in which the convex portion 41 is formed. Even when the materials 5 are combined, they can be manufactured in the same manner.

  In this case as well, the back surface side sealing material region corresponding to the inter-cell region 10 in the vicinity of the lead wire 4 or the light receiving surface side sealing material region is made flat, so that the stress applied to the lead wire 4 at the time of lamination is increased. And the possibility of deformation and disconnection is reduced. Furthermore, the reliability of the solar cell module 50 can be improved because it is possible to reduce the possibility of peeling between the lead wire 4 and the sealing material and the disconnection of the lead wire 4 during use of the solar cell module 50. .

Embodiment 4 FIG.
Further, as shown in the process cross-sectional view of the state before pressure molding in FIG. 7, both the light-receiving surface side sealing material 2 and the back surface side sealing material 5 are in sheet form, and the back surface side sealing material is used during lamination. 5 may be formed with convex portions 11. In this example, the laminate is laminated by a laminating apparatus 48 including a laminate light-receiving surface side mold 45 and a laminate back-side mold 46 formed with a laminate back-side mold convex portion 47, so that the first embodiment is used. The convex part 11 is formed in the back surface side sealing material 5 similarly to.

  In this Embodiment, the convex part 11 can be easily formed in the back surface side sealing material 5 by pressing the lamination back surface side metal mold convex part 47 against the back sheet 6 and the back surface side sealing material 5. . In this case, since both back side sealing materials can be formed using a flat sheet, workability is high. Moreover, by aligning with the position of the solar battery cell 3 and pressing the laminate back surface mold convex portion 47, it is possible to perform molding while maintaining good positional accuracy with respect to the inter-cell region.

  In addition, the back surface side sealing material 5 in which the convex portion 11 has already been formed or the light receiving surface side sealing material 2 in which the concave portion has been formed may be molded using the laminate back surface side mold convex portion 47 of the laminating device 48. In this case, the molding can be performed more efficiently.

Embodiment 5 FIG.
In the first embodiment, the convex portion 11 of the back surface side sealing material 5 is formed with a single layer structure, but may be formed so as to have a multilayer structure with different refractive indexes. FIG. 8 is a cross-sectional view showing the main part of this solar cell module, and FIG. 9 is a process cross-sectional view showing a state during lamination (before pressure molding) in the manufacturing process. In the present embodiment, the back surface side sealing material has a three-layer structure of a first layer 5a, a second layer 5b, and a third layer 5c that are configured so that the refractive index gradually increases from the solar battery cell 3 side. The convex portion 11 is also composed of three layers of a first layer 5a, a second layer 5b, and a third layer 5c. For this reason, the reflectivity in the convex part 11 improves. Further, by selecting the composition of the three layers in consideration of not only the refractive index but also mechanical strength and adhesion, it is possible to provide a solar cell module with extremely high photoelectric conversion efficiency and high reliability. .

  At the time of manufacturing, the back side sealing material 5 in the fourth embodiment is simply replaced with a three-layer sheet of the first layer 5a, the second layer 5b, and the third layer 5c. That is, by using the laminating apparatus 48 used in Embodiment 4 and using a three-layer flat sheet, all can be formed using a flat sheet, so that workability is high. Moreover, it is possible to perform molding while maintaining good positional accuracy with respect to the inter-cell region 10 by aligning with the position of the solar battery cell 3 and pressing the laminate back surface mold convex portion 47. . In addition, the back surface of the back sheet 6 is subjected to heat treatment again to be flattened.

  Also in this configuration, the convex portion 11 may be formed as large as possible while avoiding the lead wire 4, but may be formed in a linear shape in the inter-cell region 10, or as shown in FIG. You may form in a shape (it mentions later). In the case of this structure, the light that passes through the three-layer film and enters the solar battery cell 3 becomes more reliable by forming it as large as possible in the form of dots. However, the shape is not limited, and can be selected in consideration of the material and workability of the light-receiving surface side sealing material and the back surface side sealing material.

  Further, as the three-layer sheets of the first layer 5a, the second layer 5b, and the third layer 5c constituting the back side sealing material, those having different refractive indexes were used, but three sheets having the same composition were prepared. And may be laminated. In this case, since the sheet density becomes lower toward the outside of the convex portion due to the extent of the formation of the convex portion, the refractive index also changes, and the convex portion 11 having a multilayer structure is formed.

  In the first embodiment, the convex portion formed in the inter-cell region 10 is formed as large as possible avoiding the lead wire 4, but is not limited to this shape, and the light receiving surface side sealing material and the back surface side Selection is possible in consideration of the material of the sealing material, workability, and the like.

  10 to 12 are enlarged perspective views of main parts corresponding to FIG. 2-1 in the first embodiment, and the planar shapes of the convex portions 11 of the back surface side sealing material 5 are different. Others are the same.

Embodiment 6 FIG.
In the sixth embodiment, as shown in FIG. 10, convex portions 11 are formed in the inter-cell region 10 so as to form a line having a predetermined width. Since other parts are the same as those in the first embodiment, the description thereof is omitted here. The same symbols are assigned to the same parts.

  According to this structure, since the shape is simple, formation is easy. For example, as shown in the sectional view of FIG. 7, it is possible to perform the processing more efficiently when the shape processing is performed using the laminating apparatus.

Embodiment 7 FIG.
In the seventh embodiment, as shown in FIG. 11, in addition to the convex portions 11 formed to form a line having a predetermined width in the inter-cell region 10, dot-shaped convex portions 11 are formed between the lead wires 4. Is formed. Since other parts are the same as those in the first embodiment, the description thereof is omitted here. The same symbols are assigned to the same parts.

  According to this configuration, light can be guided more effectively, and the photoelectric conversion efficiency can be increased.

Embodiment 8 FIG.
In the eighth embodiment, as shown in FIG. 12, a large number of dot-like convex portions 11 are formed in the inter-cell region 10 avoiding the lead wires 4. Since other parts are the same as those in the first embodiment, the description thereof is omitted here. The same symbols are assigned to the same parts.

  According to this configuration, shape processing is simple and light can be guided more effectively. In particular, when a convex portion having a multilayer structure as shown in the fifth embodiment is formed to enhance reflectivity (scattering property), this planar shape is desirable.

  In addition, in the solar cell module of Embodiment 1, a reflective film may be formed so as to cover the surface of the convex portion 11 of the back surface side sealing material 5.

  In Embodiments 1 to 4 and 6 to 8, the back-side sealing material 5 is made of a resin containing a white inorganic pigment, but is not limited to this, from bubbles, high refractive index resins, and the like. A resin containing reflective particles is also applicable. Further, a reflective film such as a metal film may be formed on the surface of the convex portion 11. Furthermore, as in the case of the fifth embodiment, it may be composed of a multilayer body having different refractive indexes. The back surface side sealing material 5 desirably has a higher refractive index than the light receiving surface side sealing material 2, but if formed so that the refractive index is different, the scattering property at the interface can be enhanced.

  The solar cell used in the solar cell module of the above embodiment is a diffusion type solar cell in which an n-type impurity is diffused into a p-type single crystal silicon substrate to form a pn junction. Thin film solar cells, such as thin film solar cells, in which a pn junction is formed by forming a p-type amorphous silicon layer, a p-type polycrystalline silicon layer, etc. on the surface of a silicon substrate such as a p-type single crystal silicon substrate or an n-type polycrystalline silicon substrate The present invention can also be applied to other optical elements such as EL elements.

  As described above, the solar cell module and the manufacturing method thereof according to the present invention are useful for increasing the utilization efficiency of incident light.

  DESCRIPTION OF SYMBOLS 1 Translucent board | substrate, 2 Light receiving surface side sealing material, 3 Solar cell, 3a Light receiving surface side electrode, 3b Back surface electrode, 4 Lead wire, 5 Back surface side sealing material, 5a 1st layer, 5b 2nd layer, 5c 3rd layer, 6 back sheet, 7 outer frame, 10 inter-cell region, 11 back side sealing material convex, 20 incident light to inter-cell region, 21 positive incident light at front and back side sealing material interface Optical path of reflection component, 22 Optical path of scattered light of incident light at front and back side sealing material interface, 23 Reflected light at interface between refractive layer and translucent substrate, 24 refracted light, 32 Translucent substrate Incidence angle at the interface between air and air, 40 concave portion, 41 convex portion, 45 laminate light receiving surface side mold, 46 laminate back surface side mold, 47 laminate back surface side mold convex portion, 48 laminating device, 50 solar cell module.

Claims (7)

A translucent substrate, a light receiving surface side sealing material, a plurality of solar cells connected by lead wires and arranged on the same surface, a back surface side sealing material, and a back sheet are sequentially laminated, and resin A sealed solar cell module,
The back surface side sealing material disposed between the back sheet and the solar battery cell is made of a material having a different refractive index so as to form a scattering interface with respect to the light receiving surface side sealing material,
In the inter-cell region of the plurality of solar cells, the back surface side sealing material protrudes to the light incident side from the light receiving surface of the solar cells.   The solar cell module according to claim 1, wherein the back surface side sealing material contains a white inorganic pigment.   The white inorganic pigment is titanium white, zinc white, barium sulfate, lithopone, silica, or a mixture thereof, and the particle size of aggregates or primary particles dispersed in the back side sealing material is 3. The solar cell module according to claim 2, wherein the solar cell module is 5 μm or more and 5 to 30 wt% in the back surface side sealing material. The back side sealing material is
In the inter-cell region that the lead wire crosses, it is arranged on the back sheet side from the same plane as the light receiving surface of the solar battery cell,
The solar cell module according to any one of claims 1 to 3, wherein the inter-cell region where the lead wire does not cross is formed to have a convex portion on the light incident side. A translucent substrate;
A light-receiving surface side sealing material having a concave portion in a position corresponding to between cells in advance,
A plurality of solar cells connected by lead wires and arranged on the same plane;
A back surface side sealing material having a refractive index different from that of the light receiving surface side sealing material;
A step of sequentially laminating a back sheet and forming a laminate;
The laminated body is heated and pressurized to form a scattering interface in which the back surface side sealing material protrudes to the light incident side from the light receiving surface of the solar battery cell in the inter-cell region of the plurality of solar battery cells. And a step of sealing the solar cell module. A translucent substrate;
A light-receiving surface side sealing material;
A plurality of solar cells connected by lead wires and arranged on the same plane;
A back surface side sealing material having a refractive index different from that of the light receiving surface side sealing material, and having a concave portion in a position corresponding to between cells in advance,
A step of sequentially laminating a back sheet and forming a laminate;
The laminated body is heated and pressurized to form a scattering interface in which the back surface side sealing material protrudes to the light incident side from the light receiving surface of the solar battery cell in the inter-cell region of the plurality of solar battery cells. And a step of sealing the solar cell module. A translucent substrate;
A light-receiving surface side sealing material;
A plurality of solar cells connected by lead wires and arranged on the same plane;
A back side sealing material having a refractive index different from that of the light receiving surface side sealing material;
A step of sequentially laminating a back sheet and forming a laminate;
The laminated body is heated and pressed using a mold having a convex portion at a position corresponding to the inter-cell region, and the back surface side sealing material is the solar cell in the inter-cell region of the plurality of solar cells. And a step of sealing so as to constitute a scattering interface protruding to the light incident side from the light receiving surface of the solar cell module.

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