JP2009111122A - Solar cell module and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell module ensuring higher power generating efficiency and excellent reliability, and to provide a method of manufacturing the same. <P>SOLUTION: The solar cell module includes a light receiving surface 1a, a light transmitting substrate 1 having the rear surface 1b of the light receiving surface 1a, a solar cell element 2 provided on the rear surface of the light transmitting substrate 1, and a sealing material 3 for sealing the solar cell element 2. Moreover, the light transmitting substrate 1 includes a plurality of portions 16 projected to the side of rear surface 1b. The plurality of solar cell elements 2 are fixed to the plurality of projected portions 16. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solar cell module and a manufacturing method thereof.

A conventional solar cell module includes a translucent substrate, a sheet made of an ethylene vinyl acetate copolymer (hereinafter abbreviated as EVA) placed on the translucent substrate, and a plurality of pieces placed on the sheet. It has a solar cell element and a plurality of solar cell elements, and includes a sheet of EVA and a back sheet made of weathering resin such as fluororesin.
JP 2003-31824 A

  In the above-described solar cell module, it is important to improve power generation efficiency while further spread is expected. Regarding the improvement of the power generation efficiency, it is important to improve the amount of light incident on the solar cell element and to improve the reliability of the solar cell element.

  The present invention has been made in view of such problems, and an object thereof is to provide a solar cell module having high power generation efficiency and high reliability and a method for manufacturing the same.

  A solar cell module according to the present invention seals a light-transmitting substrate having a light-receiving surface and a back surface of the light-receiving surface, a solar cell element provided on the back surface of the light-transmitting substrate, and the solar cell element. And a sealing material to be stopped.

  The method for manufacturing a solar cell module according to the present invention includes a step of preparing a translucent substrate having a light receiving surface and a back surface of the light receiving surface, a solar cell element, and a sealing material, and the translucent substrate. The step of disposing the solar cell element on the back surface of the substrate, and the step of sealing the solar cell element disposed on the back surface of the translucent substrate with the sealing material.

  The solar cell module which concerns on this invention has a solar cell element arrange | positioned at the back surface of a translucent board | substrate. That is, the light receiving surface of the solar cell element is disposed in contact with the back surface of the translucent substrate. For this reason, absorption of the light between a translucent board | substrate and a solar cell element is reduced, and it becomes possible to provide a solar cell module with high power generation efficiency.

  Moreover, in the solar cell module manufacturing method according to the present invention, the solar cell element can be sealed at a temperature lower than the temperature at which EVA is softened, melted and integrated. Therefore, a decrease in the adhesive strength between the electrode of the solar cell element and the silicon substrate can be reduced, and a highly reliable solar cell module can be obtained.

  Hereinafter, embodiments of the solar cell module of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
<Solar cell module>
The solar cell module of the present embodiment includes a translucent substrate 1 having a light receiving surface 1a and a back surface 1b of the light receiving surface, a solar cell element 2, and a sealing material 3 for sealing the solar cell element 2. The solar cell module has a structure in which a plurality of solar cell elements 2 are arranged on a translucent substrate 1 and the plurality of solar cell elements 2 are sealed with a sealing material.

  FIG. 1 is a plan view (light-receiving surface side) of the solar cell module of the present embodiment. In FIG. 1, a solar cell module is provided on the outer periphery of a solar cell panel composed of a translucent substrate 1 and a string in which a plurality of solar cell elements 2 are electrically connected by connection tabs 4 and the solar cell panel. Module frame 5.

  As the translucent substrate 1, a substrate made of glass or transparent resin is used. As the glass plate, white plate glass, tempered glass, double tempered glass, heat ray reflective glass or the like is used, but generally white plate tempered glass having a thickness of about 3 mm to 5 mm is used. Moreover, when resin is used as the translucent board | substrate 1, the weight reduction of a solar cell module is attained. The resin is acrylic, polyvinyl chloride, polycarbonate, PET (polyethylene terephthalate), or the like. In particular, when acrylic is used, since the light transmittance is high, the power generation efficiency of the solar cell module is excellent. As such a translucent substrate 1, for example, a flat plate having a thickness of about 5 mm is used.

  FIG. 2 is a plan view of the light receiving surface side of the solar cell element 2 used in the solar cell module of the present embodiment. FIG. 3 is a plan view of the light receiving surface side of the solar cell element 2 in which the connection tabs 4 are connected to the bus bar electrodes 25 on the light receiving surface side and the back surface side.

  The solar cell element 2 of the present embodiment includes a semiconductor substrate 21, a bus bar electrode 25 formed on the light receiving surface of the semiconductor substrate 21, and a finger electrode 26 electrically connected to the bus bar electrode 25. The bus bar electrode 25 has a function of collecting optical carriers of the finger electrode 26, and the connection tab 4 is connected to the surface. When the surface of the bus bar electrode 25 is coated with solder, the bus bar electrode 25 can be protected and the connection tab 4 can be easily attached.

  The solar cell element 2 of the present embodiment is disposed on the back surface 1 b of the translucent substrate 1. 4 is a cross-sectional view of the solar cell panel of the solar cell module shown in FIG. In the solar cell module of the present embodiment, the solar cell element 2 is in a state where the light receiving surface is in close contact with the back surface 1b of the translucent substrate 1 as shown in FIG. Accordingly, light is hardly absorbed between the solar cell element 3 and the translucent substrate 1. Therefore, the photovoltaic power generation efficiency of the solar cell module is improved.

  2 and 3, the finger electrodes 26 intersect perpendicularly with the bus bar electrodes 25, and are formed on the plurality of semiconductor substrates 21 in parallel with the sides of the solar cell element 2. Since a plurality of finger electrodes 26 are formed on the surface of the solar cell element 2, the collection efficiency of photogenerated carriers is improved. The bus bar electrode 25 and the finger electrode 26 are similarly formed on the back surface (non-light receiving surface) side of the solar cell element 2.

  Such a solar cell element 2 is made of, for example, single crystal silicon or polycrystalline silicon having a thickness of about 0.2 to 0.4 mm and a size of about 150 to 160 mm square. Inside the solar cell element 2 is formed a PN junction in which a P layer containing a large amount of P-type impurities such as boron and an N layer containing a large amount of N-type impurities such as phosphorus are in contact. The bus bar electrode 25 and the finger electrode 26 are formed by screen printing a conductive paste mainly composed of silver or the like. The width of the finger electrode 26 is, for example, about 0.1 to 0.2 mm, and the interval between the plurality of finger electrodes 26 is about 2 to 4 mm. Further, the bus bar electrodes 25 to which the connection tabs 4 are attached are formed on the semiconductor substrate 21 with a width of about 1 to 3 mm and about 2 to 3 pieces.

  The sealing material 3 has a function of protecting and sealing the solar cell element 2 and is disposed on the solar cell element 2 disposed on the translucent substrate 1. By disposing the sealing material 3 on the solar cell element 2, even if a force is applied from the back side of the solar cell module, cracking of the solar cell 2 and the like can be reduced. Protect.

  Since such a sealing material 3 molds the solar cell element 2, it has fluidity in a state before solidifying. As the sealing material 3, a material that is solidified by a change with time, heating, or irradiation with ultraviolet rays is used. Examples of the ultraviolet curable resin used in the present embodiment include a urethane acrylate resin and an epoxy acrylate resin. Moreover, as resin which hardens | cures with a time-dependent change, a silicone resin is mentioned, for example. Moreover, as a thermosetting resin, an epoxy resin, a phenol resin, etc. are mentioned, for example. In particular, when a silicone resin that is solidified by aging in about 6 to 24 hours after molding is used, the number of steps can be reduced because it is not necessary to perform a treatment such as heating after molding. Furthermore, when a silicone resin is used, since the moisture permeability is low, it can be suitably used from the viewpoint of the weather resistance of the solar cell module.

  Since such a sealing material 3 molds the solar cell element 2, it has fluidity in a state before solidifying. As the sealing material 3, a material that is solidified by a change with time, heating, or irradiation with ultraviolet rays is used. The sealing material 3 used in the present embodiment is an epoxy resin, an acrylic resin, a phenol resin, a polyimide resin, an epoxy acrylate resin, or the like. In particular, when a silicone resin that is solidified by aging in about 6 to 24 hours after molding is used, the number of steps can be reduced because it is not necessary to perform a treatment such as heating after molding. Furthermore, when a silicone resin is used, since the moisture permeability is low, it can be suitably used from the viewpoint of the weather resistance of the solar cell module.

  The connection tab 4 has a function of electrically connecting the plurality of solar cell elements 2. One end of the connection tab 4 shown in FIG. 3 is soldered onto the light receiving surface side bus bar electrode 5 of the solar cell element 2. Moreover, the other end part of the connection tab 4 is soldered to the back surface side bus-bar electrode of another adjacent solar cell element, and the adjacent solar cell elements are electrically connected.

  Such a connection tab 4 is formed by, for example, coating the surface of a low resistance solar cell element wiring material such as copper or aluminum by plating or dipping to about 70 μm. The width of the connection tab 4 is equal to or less than the width of the bus bar electrode 25 so that the connection tab 3 does not shade the light receiving surface of the solar cell element 2 when soldered to the bus bar electrode 25. Moreover, the length of the connection tab 4 has the length which connects between adjacent solar cell elements and overlaps with the bus-bar electrode 25 of an adjacent solar cell element. When a polycrystalline silicon solar cell element of about 150 mm square is used, the connection tab 3 has a width of about 1 to 3 mm, a thickness of about 0.1 to 0.3 mm, and a length of about 240 to 300 mm. As shown in FIG. 3, when the connection tab 3 is arranged so as to overlap almost all the bus bar electrodes 25 of the solar cell element 2, the resistance component of the solar cell element is reduced.

  The solar cell module of the present embodiment includes a module frame 5 provided around the solar cell panel. The module frame 5 has a role to reinforce the solar cell panel and a role to be attached to a frame or the like. In FIG. 1, the module frame 5 is composed of a long side frame along the long side of the solar cell panel and a pair of short side frames along the short side, and these are coupled by screwing together. It has become. The module frame 5 is made of, for example, an aluminum extruded product.

<< Solar Cell Module Manufacturing Method >>
5 and 6 show the structure and manufacturing method of the solar cell module according to this embodiment.

  The manufacturing method of the solar cell module according to the present embodiment is performed according to the following procedure.

(A) A translucent substrate 1 having a light receiving surface 1a and a back surface 1b, a solar cell element 3, and a sealing material 13 before solidification are prepared.

(A) The solar cell element 3 is disposed on the back surface 1 b of the translucent substrate 1.

(C) The solar cell element 3 disposed on the back surface 1b of the translucent substrate 1 is sealed with a sealing material 13 before solidification.

  In a conventional solar cell module manufacturing method, each member is superimposed on a light-transmitting substrate, and this solar cell module is heated and pressed under reduced pressure by a device called a laminator. EVA is softened, melted and integrated. For this reason, the temperature of the solar cell element rises to a temperature (about 120 to 160 ° C.) at which the EVA softens, melts, and crosslinks during the process, and the adhesive strength between the electrode of the solar cell element and the silicon substrate decreases. was there. In the manufacturing method of the solar cell module of the present embodiment, the sealing resin 13 is cured due to a change with time or the like, so that the solar cell element 2 can be sealed at 45 ° C. or lower. It is possible to prevent a decrease in the adhesive strength between the electrode and the silicon substrate. Moreover, the crack and crack which arise in a solar cell element can also be reduced.

  In the process (A) of the present embodiment, the translucent substrate 1 is inserted into the mold 15 on the work table. On the translucent substrate 1, a string composed of a plurality of solar cell elements 2 connected by the connection tab 4 is placed. For example, a frame 15 made of stainless steel or aluminum having a thickness of about 1 to 3 mm and a width of about 30 to 50 mm is prepared by welding or screwing. Further, the size of the mold 15 is produced so that the inner dimension 15t of the mold 15 is larger than the outer dimension 1t of the translucent substrate 1 by about 0.5 to 2 mm. Such a mold 15 can also be used as the frame 5 of the solar cell module described above. In the manufacturing method of the solar cell module of the present embodiment, since the sealing resin 13 is injected into the mold 15, a sheet-like sealing resin back sheet is not used. For this reason, when manufacturing solar cell modules of various sizes, there is no need to prepare an EVA sheet or back sheet of a sealing material corresponding to the size of each solar cell module. Furthermore, in the manufacturing method of the solar cell module of the present embodiment, since the sealing resin 13 is injected into the mold 15, a sheet-shaped sealing resin back sheet is not used. For this reason, since it is not necessary to superimpose each member, such as EVA sheet | seat of a sealing material, and a back surface sheet, on a predetermined position, it becomes possible to reduce a man-hour.

  In the step (c) of the present embodiment, sealing of the solar cell element 2 is performed by discharging and injecting the sealing material 13 before solidification into the mold 15 from the injector 14 (FIG. 6). At this time, in order to protect the solar cell element 2 from impact and moisture intrusion, the thickness of the sealing material 13 before solidification is made thicker than the thickness of the solar cell element 2. The sealing material 13 before solidification has a thickness of about 3 to 15 mm from the back surface side of the solar cell element 2, for example. After being injected onto the solar cell element 2, the sealing material 13 is solidified.

  The injector 14 used in the step (c) stores the sealing material 13 therein, and discharges the sealing material 13 from the tip of the injector 14 by a gas pressure such as nitrogen and an electromagnetic valve. When the injector 14 is configured to be freely driven in a plurality of directions at a predetermined speed by a servo motor controlled by a sequencer or the like, it is easy to apply the sealing material 12 uniformly inside the mold material 11.

  When the mold 15 is not used as the frame 5, after the sealing material 12 is solidified after the step (c), the sealing material on the inner surface of the mold 15 is separated with a cutter knife or the like, and the mold 15 is extracted. Thereafter, the module frame 4 is fitted on the outer periphery of the solar cell panel, and the four corners of the module frame are screwed to complete the solar cell module.

(Second Embodiment)
A second embodiment of the solar cell module of the present invention will be described with reference to FIGS.

  FIG. 7 is a perspective view showing a translucent substrate 10 used in the solar cell module of the second embodiment, and FIG. 8 is a cross section of the solar cell module in which the translucent substrate 10 shown in FIG. 7 is used. FIG.

  In the present embodiment, a plurality of projecting portions 16 are provided on the surface of the translucent substrate 10 on the side where the solar cell element 2 is disposed. Solar cell element 2 is placed between adjacent protrusions 16. Thus, the translucent substrate 10 has a plurality of projecting portions 16 projecting to the back surface side, and the solar cell element 2 is located between the adjacent projecting portions 16 of the translucent substrate 10 (the space in FIG. 7). The solar cell element 2 can be easily positioned by being fixed to the bottom 16b) of 16s.

  Here, the “back surface” of the translucent substrate 10 on which the solar cell element 2 is arranged in the present embodiment refers to the bottom 16 b of the space 16 between the protrusions 16. The width between the adjacent protrusions 16 is approximately the same as the side length of the solar cell element.

  Such protrusions 16 are created, for example, by cutting a glass or acrylic resin into a predetermined size on a flat plate of glass or resin and pasting it with a transparent adhesive. In addition, there is a method of manufacturing the transparent substrate 1 together with the light-transmitting substrate 1 by injection molding a transparent resin at a low cost. Such protrusions 16 are not bar-shaped as shown in FIG. 7, but may be hemispherical that supports the solar cell element 2 with dots.

<< Solar Cell Module Manufacturing Method >>
The manufacturing method of the solar cell module of this embodiment is performed in the following procedure.

  First, the translucent substrate 10 shown in FIG. 7 is inserted into the mold 15 on the work table.

Next, a plurality of solar cell elements 2 connected by the connection tabs 3 are placed between the plurality of projecting portions 16 of the translucent substrate 1 inside the mold 15. When the connection tab 3 is connected between the electrode on the upper surface of the solar cell element and the electrode on the lower surface of the adjacent solar cell element, a plurality of the connection tabs 3 connected in series by the connection tab 3 in the X direction of FIG. A solar cell element is placed. In the case of a back-contact type solar cell element, a plurality of solar cell elements connected in series in the Y direction of FIG. In any case, two side surfaces of each of the plurality of solar cell elements 2 are held by the protrusions 16.

Then, the sealing material 13 before solidifying into the inside of the mold 15 is discharged and injected from the injector 14, and the back surface of the solar cell element 2 is sealed with the sealing material 13 to obtain a solar cell module.

(Third embodiment)
A third embodiment of the solar cell module of the present invention will be described with reference to FIGS.

  FIG. 9 is a perspective view showing a translucent substrate 20 used in the solar cell module of the third embodiment, and FIG. 10 is a cross section of the solar cell module in which the translucent substrate 20 shown in FIG. 9 is used. FIG.

  In the present embodiment, a plurality of projecting portions 26 are provided on the surface of the translucent substrate 20 on the side where the solar cell element 2 is disposed. The protrusion part 26 of this Embodiment is larger than the protrusion part 16 shown in 2nd Embodiment.

  In the present embodiment, the solar cell element 2 is placed on the protruding portion 26. Since the solar cell element 2 is directly placed on the projecting portion 26, sunlight passes only through the translucent substrate 20 before reaching the solar cell element 2 from outside the solar cell module (generally, the atmosphere). pass. Accordingly, it is possible to reduce the amount of light emitted from the solar cell module without entering the solar cell element due to total reflection or the like.

  Here, the “back surface” of the translucent substrate 20 on which the solar cell element 2 is arranged in the present embodiment refers to the surface (upper surface in FIG. 10) 26 b of the protruding portion 26.

(Fourth embodiment)
A fourth embodiment of the solar cell module of the present invention will be described with reference to FIGS.

  FIG. 11 is a perspective view showing a translucent substrate 30 used in the solar cell module of the fourth embodiment, and FIG. 12 is a cross section of the solar cell module in which the translucent substrate 30 shown in FIG. 10 is used. FIG.

  In the present embodiment, a plurality of projecting portions 36 are provided on the surface of the translucent substrate 30 on the side where the solar cell element 2 is disposed. The end of the solar cell element 2 is directly placed on the plurality of protrusions 36.

  In the present embodiment, the sealing material 13 wraps around the space 36 s between the plurality of protrusions 36. Thus, by providing the solar cell element 2 on the protruding portion 36 of the translucent substrate 30, the appearance on the light receiving surface side of the solar cell module can be improved. Moreover, it becomes possible to set the thickness of the sealing material 3 to arbitrary thickness by adjusting the height of the protrusion part 36. FIG. By making the height of the protruding portion 36 lower than the thickness of a conventional EVA sheet or the like, the light absorption of the sealing material can be kept low, and the power generation efficiency can be improved.

  The size of the protruding portion 36 is, for example, about 0.3 to 3 mm in height and about 4 to 8 mm in width, and the length is about 40 to 60% of the length difference between the sides of the solar cell element.

  Moreover, in the manufacturing method of the solar cell module of the present embodiment, the plurality of solar cell elements 2 connected by the connection tab 3 are placed on the protruding portion 36 of the translucent substrate 30 inside the mold 15. Moreover, the solar cell element 2 can be protected from impact and humidity intrusion by injecting the sealing material 13 before solidification about 3 to 15 mm higher than the solar cell element 2.

  Further, the height of the protrusions 36 on the translucent substrate 1 before the solar cell element 2 is placed in advance so that the sealing material 13 before solidification easily wraps around the space 36s between the plurality of protrusions 36. Until 30% to 70% of the sealing material 13 before solidification is injected, and then the solar cell element 3 is placed on the protruding portion 36, and the sealing material 13 before solidification is injected again, The solar cell element 2 may be sealed.

  Further, the protruding portions 36 of the translucent substrate 30 may be placed not only on the two sides on the back side of the solar cell element 2 but on all four sides. Further, the protruding portion 36 is not a rod-shaped member as shown in FIG. 11, but may be a hemispherical member that supports the solar cell element 2 with dots.

  In addition, this invention is not limited to the said embodiment, Many corrections and changes can be added within the scope of the present invention. For example, the solar cell element is not limited to a crystalline solar cell such as a single crystal or polycrystalline silicon, and can be applied to a thin film solar cell. Further, it can be used as a frameless type module without a module frame.

It is a top view by the side of the light-receiving surface of the solar cell module of 1st Embodiment. It is a top view by the side of the light-receiving surface of the solar cell element used for the solar cell module of FIG. FIG. 3 is a plan view of a light receiving surface side of a solar cell element in which connection tabs are connected to bus bar electrodes on the light receiving surface side and the back surface side of the solar cell element shown in FIG. 2. It is sectional drawing of the solar cell panel which comprises the solar cell module of FIG. It is a disassembled perspective view of the solar cell module of 1st Embodiment. The manufacturing method of the solar cell module of 1st Embodiment is shown. It is a perspective view which shows the translucent board | substrate of the solar cell module of 2nd Embodiment. It is sectional drawing of the solar cell module of 2nd Embodiment. It is a perspective view which shows the translucent board | substrate of the solar cell module of 3rd Embodiment. It is sectional drawing of the solar cell module of 3rd Embodiment. It is a perspective view which shows the translucent board | substrate of the solar cell module of 4th Embodiment. It is sectional drawing of the solar cell module of 4th Embodiment.

Explanation of symbols

1; Translucent substrate 2; Solar cell element 4; Module frame

Claims (12)

A translucent substrate having a light receiving surface and a back surface of the light receiving surface;
A solar cell element provided on the back surface of the translucent substrate;
A sealing material for sealing the solar cell element;
Solar cell module with The solar cell module according to claim 1, wherein the translucent substrate is a resin. The solar cell module according to claim 1, wherein the sealing material is an ultraviolet curable resin. The solar cell module according to claim 1, wherein the sealing material is a silicone resin. The solar cell module according to claim 1, wherein the translucent substrate has a protruding portion that protrudes toward the back surface side. The solar cell module according to claim 5, wherein the solar cell element is disposed on the protruding portion of the translucent substrate. The solar cell according to claim 5, wherein the translucent substrate has a plurality of the protruding portions, and the solar cell element is disposed between the plurality of adjacent protruding portions. module. Preparing a light transmissive substrate having a light receiving surface and a back surface of the light receiving surface, a solar cell element, and a sealing material;
Arranging the solar cell element on the back surface of the translucent substrate;
Sealing the solar cell element disposed on the back surface of the translucent substrate with the sealing material;
The manufacturing method of the solar cell module which has. The method for manufacturing a solar cell module according to claim 8, wherein the sealing material is a silicone resin. Preparing the frame;
The method for manufacturing a solar cell module according to claim 8, further comprising a step of disposing the translucent substrate inside the frame. The method for manufacturing a solar cell module according to claim 10, wherein the sealing of the solar cell element includes a step of pouring the resin into the frame. The solar cell module manufacturing method according to any one of claims 8 to 11, wherein the sealing of the solar cell element is performed at 45 ° C or lower.

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