JP2011044751A - Solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell module wherein the occurrence of warpage and cracks of solar cells can be suppressed. <P>SOLUTION: The solar cell module has: a first solar cell provided with a connection electrode for connecting a wiring material to the light incidence side; and a second solar cell provided with a connection electrode for connecting a wiring material to the light incidence side, wherein the first solar cell and the second solar cell are electrically connected by the wiring materials, and each of one end part sides of the connection electrodes has a tapered shape. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a solar cell module including a plurality of solar cells connected to each other by a wiring material.

  Solar cells are expected as a new energy source because they can directly convert clean and infinitely supplied solar energy into electrical energy.

  Generally, the output per solar cell is about several watts. Therefore, when a solar cell is used as a power source for a house or a building, a solar cell module whose output is increased by connecting a plurality of solar cells is used.

  The solar cell module includes a plurality of solar cells sealed by a sealing material between the light-receiving surface side protective material and the back surface side protective material.

  The plurality of solar cells are arranged along the arrangement direction and are electrically connected to each other by a wiring material. Specifically, the wiring member is disposed along the arrangement direction on the light receiving surface of one solar cell and on the back surface of another solar cell adjacent to the one solar cell (see, for example, Patent Document 1). ). The planar shape of the wiring material is a rectangle, and the end surface of the wiring material in the arrangement direction is orthogonal to the arrangement direction.

JP 2002-359388 A

Here, the linear expansion coefficient of the wiring material (copper linear expansion coefficient: about 17 × 10 ⁻⁶ (1 / K)) is equal to the linear expansion coefficient of the semiconductor substrate (Si linear expansion coefficient: about 3.4 × 10 ^{− 6} (1 / K)). Therefore, internal stress is generated in the wiring material according to the temperature change when the wiring material is thermally bonded to the solar cell.

  Such an internal stress increases toward the end of the wiring material in the arrangement direction. Therefore, the solar cell is most affected by the internal stress of the wiring material at the contact point with one end of the wiring material in the arrangement direction. As a result, there is a problem that the solar cell is likely to be cracked starting from a contact point between one end of the wiring member in the arrangement direction and the solar cell.

  On the other hand, the solar cell is likely to warp due to the influence of the internal stress of the wiring material. Such warpage increases as the internal stress of the wiring member increases toward one end, so that there is a problem that the warpage is particularly large in a portion of the solar cell that is in contact with one end of the wiring member.

  This invention is made | formed in view of the above-mentioned situation, and aims at providing the solar cell module which can suppress generation | occurrence | production of the curvature and crack of a solar cell.

A solar cell module according to a feature of the present invention includes a first solar cell provided with a connection electrode for connecting a wiring material on the light incident side and a second electrode provided with a connection electrode for connecting the wiring material on the light incident side. A solar cell module having a solar cell, wherein the first solar cell and the second solar cell are electrically connected to each other by the wiring member,
The gist of the present invention is that the one end side of the connection electrode is a solar cell module having a tapered shape.

ADVANTAGE OF THE INVENTION According to this invention, the solar cell module which can suppress generation | occurrence | production of the curvature and crack of a solar cell can be provided.

It is a side view of the solar cell module 100 which concerns on embodiment of this invention. It is a top view of the solar cell 10 which concerns on embodiment of this invention. It is a top view of the solar cell string 1 which concerns on embodiment of this invention. It is a figure for demonstrating the manufacturing method of the solar cell module 100 which concerns on embodiment of this invention. It is a figure for demonstrating the difference between the wiring material 11 which concerns on embodiment of this invention, and the conventional wiring material 110. FIG. It is a figure for demonstrating the difference between the manufacturing method of the wiring material 11 which concerns on embodiment of this invention, and the manufacturing method of the conventional wiring material 110. FIG. It is a top view of the wiring material 11 which concerns on embodiment of this invention.

Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.
(Configuration of solar cell module)
A schematic configuration of a solar cell module 100 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a side view of a solar cell module 100 according to an embodiment.

  The solar cell module 100 includes a solar cell string 1, a light receiving surface side protective material 2, a back surface side protective material 3, and a sealing material 4.

  The solar cell string 1 is sealed with a sealing material 4 between the light receiving surface side protective material 2 and the back surface side protective material 3. The solar cell string 1 includes a plurality of solar cells 10 and a plurality of wiring members 11. The solar cells 10 are electrically connected to each other by the wiring members 11. The detailed configuration of the solar cell string 1 will be described later.

  Each solar cell 10 has a light receiving surface that faces the light receiving surface side protective material 2, and a back surface that is provided on the opposite side of the light receiving surface and faces the back surface side protective material 3. The solar cells 10 are arranged along the arrangement direction H. The detailed configuration of the solar cell 10 will be described later.

  The light receiving surface side protection member 2 is disposed on the light receiving surface side of each solar cell 10 and protects the surface of the solar cell module 100. As the light-receiving surface side protective material 2, glass having translucency and water shielding properties, translucent plastic, or the like can be used.

  The back surface side protective material 3 is disposed on the back surface side of each solar cell 10 and protects the back surface of the solar cell module 100. As the back surface side protective material 3, a resin film such as PET (Polyethylene Terephthalate), a laminated film having a structure in which an Al foil is sandwiched between resin films, and the like can be used.

  The sealing material 4 seals the solar cell string 1 between the light receiving surface side protective material 2 and the back surface side protective material 3. As the sealing material 4, a translucent resin such as EVA, EEA, PVB, silicon, urethane, acrylic, or epoxy can be used.

  An Al frame (not shown) can be attached to the outer periphery of such a solar cell module 100.

(Configuration of solar cell)
Below, the structure of the solar cell 10 which concerns on embodiment is demonstrated, referring drawings. FIG. 2A is a plan view of the solar cell 10 as viewed from the light receiving surface side. FIG.2 (b) is the top view which looked at the solar cell 10 from the back surface side.

  As shown in FIGS. 2A and 2B, the solar cell 10 includes a photoelectric conversion unit 20, a thin wire electrode 30, and a connection electrode 40. Moreover, the solar cell 10 has the light-receiving surface 10A which receives sunlight, and the back surface 10B provided in the opposite side of the light-receiving surface 10A. Each of the light receiving surface 10 </ b> A and the back surface 10 </ b> B is a main surface of the solar cell 10. The thin wire electrode 30 and the connection electrode 40 are similarly formed in a comb shape on the light receiving surface 10 </ b> A and the back surface 10 </ b> B of the solar cell 10.

  The photoelectric conversion unit 20 generates photogenerated carriers by receiving light. The photogenerated carrier refers to holes and electrons generated by absorption of sunlight into the photoelectric conversion unit 20. The photoelectric conversion unit 20 includes a semiconductor junction such as a pn-type junction or a pin junction. The photoelectric conversion unit 20 can be formed using a general semiconductor material such as a crystalline semiconductor material such as single crystal Si or polycrystalline Si, or a compound semiconductor material such as GaAs or InP.

  The thin wire electrode 30 is a collection electrode that collects photogenerated carriers from the photoelectric conversion unit 20. A plurality of fine wire electrodes 30 are formed on the photoelectric conversion unit 20 along a direction substantially orthogonal to the arrangement direction H. The thin wire electrode 30 can be formed of, for example, a resin-type conductive paste or a sintered-type conductive paste (ceramic paste). In addition, the dimension and the number of the thin wire electrodes 30 can be set to an appropriate number in consideration of the size and physical properties of the photoelectric conversion unit 20. For example, when the size of the photoelectric conversion unit 20 is about 100 mm square, about 50 fine wire electrodes 30 can be formed. Note that, on the back surface 10B of the solar cell 10, a collecting electrode that covers the entire back surface 10B may be formed instead of the thin wire electrode 30.

  The connection electrode 40 is an electrode for connecting the wiring material 11. The connection electrode 40 is formed along the arrangement direction H on the photoelectric conversion unit 20. The connection electrode 40 can be formed of a resin-type conductive paste, a sintered-type conductive paste (ceramic paste), or the like. The dimensions and the number of connection electrodes 40 can be set to an appropriate number in consideration of the size and physical properties of the photoelectric conversion unit 20. For example, when the dimension of the photoelectric conversion unit 20 is about 100 mm square, two connection electrodes 40 having a width of about 1.5 mm can be formed.

Here, the connection electrode 40 according to the present embodiment is formed in a tapered shape along the arrangement direction. That is, as shown in FIGS. 2A and 2B, the planar shape of the connection electrode 40 is a triangle. This shape is set so as to correspond to the shape of the wiring material 11 described later.
(Configuration of solar cell string)
Below, the structure of the solar cell string 1 which concerns on embodiment is demonstrated, referring drawings. Fig.3 (a) is the top view which looked at the solar cell string 1 from the light-receiving surface side. FIG.3 (b) is the top view which looked at the solar cell string 1 from the back surface side.

  As shown in FIG. 3, each wiring member 11 is electrically connected to one solar cell 10 and another solar cell 10 adjacent to one solar cell 10. Specifically, one end portion of the wiring member 11 is connected along the arrangement direction H to a connection electrode 40 (see FIG. 2A) formed on the light receiving surface 10A of one solar cell 10. . The other end of the wiring member 11 is connected to a connection electrode 40 (see FIG. 2B) formed on the back surface 10B of another solar cell 10. Thereby, one solar cell 10 and the other solar cell 10 are electrically connected in series. In addition, the wiring material 11 is bend | folded in the thickness direction of a solar cell module between each solar cell 10 (refer FIG. 1).

  Here, it should be noted that one end portion of the wiring member 11 according to the present embodiment is formed in a tapered shape along the arrangement direction. Specifically, as shown in FIG. 3A, the width of one end portion of the wiring member 11 becomes narrower as the distance from the other solar cell 10 increases in a plan view when one solar cell 10 is viewed from the light receiving surface side. It has become.

  In addition, it should be noted that the other end portion of the wiring member 11 according to the present embodiment is formed in a tapered shape along the arrangement direction. Specifically, as shown in FIG. 3B, the width of the other end portion of the wiring member 11 increases as the distance from the one solar cell 10 increases in plan view when other solar cells 10 are viewed from the light receiving surface side. It is narrower.

  The wiring material 11 is comprised by the low resistance body and the conductor which covers the outer periphery of a low resistance body, for example. As the low resistance body, a thin plate or twisted copper, silver, gold, tin, nickel, aluminum, or an alloy thereof can be used. As the conductor, lead-free solder plating, tin plating, or the like can be used. The wiring member 11 is connected to the connection electrode 40 using a resin adhesive, solder, or the like. As will be described later, the planar shape of the wiring member 11 is a substantially parallelogram.

(Method for manufacturing solar cell module)
Next, the manufacturing method of the solar cell module 100 is demonstrated, referring drawings.

  First, the wiring member 11 is formed by cutting the metal wire along the cutting direction S. Specifically, as shown in FIG. 4A, a predetermined amount of the metal wire 12 wound around the cylindrical bobbin 50 is pulled out along the pull-out direction A by a plurality of rollers 51. Subsequently, the metal wire 12 is cut by the cutting blade 52. By repeating this process, the wiring member 11 having a predetermined length l is continuously formed as shown in FIG. As shown in the figure, the cutting direction S for cutting the metal wire 12 is a direction that intersects the short direction T perpendicular to the longitudinal direction N of the metal wire 12. Therefore, the planar shape of the wiring member 11 is formed in a substantially parallelogram.

  Next, one end of the wiring member 11 is connected to the light receiving surface 10 </ b> A of one solar cell 10, and the other end of the wiring member 11 is connected to the back surface 10 </ b> B of the other solar cell 10. Specifically, the wiring member 11 is bonded to the connection electrode 40 by soldering or the like. By repeating this process, the solar cell string 1 shown in FIG. 3 is formed.

  Next, an EVA (sealing material 4) sheet, a solar cell string 1, an EVA (sealing material 4) sheet, and a PET sheet (back surface side protection material 3) are sequentially placed on the glass substrate (light-receiving surface side protection material 2). Laminate to form a laminate. Subsequently, EVA is cured by heat-pressing the laminate from above and below. Thus, the solar cell module 100 is manufactured.

  Note that a terminal box, an Al frame, or the like can be attached to the solar cell module 100.

(Function and effect)
In the solar cell module 100 according to the embodiment, one end of the wiring member 11 is connected to the light receiving surface 10A of one solar cell 10 along the arrangement direction H, and the other end of the wiring member 11 is arranged in the arrangement direction. Along H, the connection is made on the back surface 10 </ b> B of one solar cell 10. In a plan view when one solar cell 10 is viewed from the light receiving surface 10 </ b> A side, the width of one end portion of the wiring member 11 becomes narrower as the distance from the other solar cell 10 increases.

  Thus, one end of the wiring member 11 is formed in a tapered shape along the arrangement direction H. That is, the cross-sectional area of the wiring member 11 at the cut surface orthogonal to the arrangement direction H becomes smaller toward one end of the wiring member 11. Therefore, the internal stress of the wiring material 11 generated according to the temperature change when the wiring material 11 is thermally bonded to the solar cell 10 becomes smaller toward one end of the wiring material 11. As a result, it is possible to prevent the solar cell from cracking starting from one end of the wiring member 11.

Specifically, as shown in FIG. 5A, the internal stress σ (kgf / mm ² ) of the wiring material 11 increases toward the end point a of the wiring material 11 (σ _a > σ _b > σ _c > Σ _d ). On the other hand, the cross-sectional area S (mm ² ) of the wiring material 11 becomes smaller toward the end point a of the wiring material 11 (0≈S ₁₀ <S ₁₁ <S ₁₂ <S ₁₃ ). Note that the points b, c, and d are located at distances x, 2x, and 3x from the end point a.

Further, as shown in FIG. 5B, the internal stress σ ′ (kgf / mm ² ) of the conventional wiring member 110 becomes larger toward the end point _a ′ of the wiring member 110 (σ _a ′> σ _b ′). > Σ _c ′> σ _d ′). On the other hand, the cross-sectional area S ′ (mm ² ) of the wiring material 110 is substantially constant regardless of the distance from the end point a ′ of the wiring material 110 (S ₁₀ ′ = S ₁₁ ′ = S ₁₂ ′ = S ₁₃ ′). ).

  Here, the tensile force F in the L direction inside the wiring member is calculated by the product of the internal stress and the cross-sectional area. Since the cross-sectional area of the wiring member 11 decreases toward the end point a, the tensile force in the vicinity of the end point a of the wiring member 11 is smaller than the tensile force in the vicinity of the end point a ′ of the wiring member 110. As a result, according to the wiring member 11 according to the present embodiment, cracking of the solar cell starting from the vicinity of the end point can be suppressed as compared with the conventional wiring member 110.

Further, the area S ₂ of the bottom surface where the wiring material 11 according to the present embodiment contacts the solar cell 10 is smaller than the area S ₂ ′ of the bottom surface where the conventional wiring material 110 contacts the solar cell 10. Therefore, according to the wiring member 11 according to the present embodiment, the influence of the tensile force inside the wiring member on the solar cell can be reduced as compared with the conventional wiring member 110. As a result, according to the wiring member 11 according to the present embodiment, it is possible to suppress the warpage of the solar cell 10.

  Moreover, since the width | variety of the other end part of the wiring material 11 which concerns on this embodiment is narrow as it leaves | separates from one solar cell 10, the effect demonstrated above can be acquired also about the other solar cell 10. FIG.

  Moreover, the wiring material 11 is electrically connected to many thin wire electrodes 30 as it approaches other solar cells 10. Therefore, the number of photogenerated carriers (electrons or holes) moving in the wiring material 11 increases as the distance from the other solar cell 10 increases. Here, the cross-sectional area of the one end portion of the wiring member 11 is wider as it approaches another solar cell 10. Therefore, according to the wiring material 11 according to the present embodiment, the smooth movement of the photogenerated carrier in the wiring material 11 can be maintained.

  Further, the shape of the connection electrode 40 is tapered to reflect the shape of the wiring material 11. For this reason, the light shielding area by the connection electrode 40 and the wiring material 11 on the light incident side can be reduced as compared with the conventional case. As a result, since the amount of light incident on the photoelectric conversion unit 20 can be increased, the amount of photogenerated carriers generated in the photoelectric conversion unit 20 can be increased.

  In the method for manufacturing the solar cell module 100 according to the present embodiment, the wiring member 11 is formed by cutting the metal wire 12 along the cutting direction S. Here, since the cutting direction S is a direction intersecting with the short direction T of the metal wire 12, the wiring member 11 is formed in a substantially parallelogram. Therefore, more wiring members 11 can be produced as compared with the case where the metal wire 12 is cut along the short direction T. As a result, the manufacturing cost of the solar cell module 100 can be reduced.

  Specifically, as shown in FIGS. 6A and 6B, when a metal wire 12 having a length of 4 l is used to form a wiring material having a length l, cutting is performed along the short direction T. As a result, four conventional wiring members 110 can be formed. On the other hand, by cutting along the cutting direction S, seven wiring members 11 according to the present embodiment can be formed from the metal wire 12 having a length of 4 l.

(Other embodiments)
Although the present invention has been described according to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the wiring member 11 is connected to the light receiving surface 10A of one solar cell 10 and the back surface 10B of the other solar cell 10. The light receiving surface 10 </ b> A and the light receiving surface 10 </ b> A of another solar cell 10 may be connected. In this case, if the polarity of the light receiving surface 10A of one solar cell 10 and the polarity of the light receiving surface 10A of the other solar cell 10 are different, the one solar cell 10 and the other solar cell 10 are electrically connected. Connected in series.

  Moreover, in the said embodiment, although both the one end part and the other end part of the wiring material 11 were formed in the taper shape, only one side may be formed in the taper shape.

  Moreover, in the said embodiment, although the edge part of the wiring material 11 was sharply formed in planar view, it is not restricted to this. The end part of the wiring material 11 should just be formed in the taper shape. Specifically, for example, the end portion of the wiring member 11 may be formed in a shape as shown in FIGS.

  Moreover, in the said embodiment, although the electrode 40 for a connection was formed in the taper shape, it is not restricted to this. For example, the connection electrode 40 may be formed in a rectangular shape as in the conventional case. Even in this case, the influence of the tensile force inside the wiring member 11 on the solar cell 10 can be reduced, so that the solar cell 10 can be prevented from warping or cracking.

  Although not particularly mentioned in the above embodiment, the metal wire 12 wound around the bobbin 50 has a curl, so when the metal wire 12 is cut by the cutting blade 52, the curl of the metal wire 12 is You may correct it.

  As described above, the present invention naturally includes various embodiments not described herein. Accordingly, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Solar cell string 2 ... Light-receiving surface side protective material 3 ... Back surface side protective material 4 ... Sealing material 10 ... Solar cell 11 ... Wiring material
DESCRIPTION OF SYMBOLS 12 ... Metal wire 20 ... Photoelectric conversion part 30 ... Fine wire electrode 40 ... Connection electrode 50 ... Bobbin 51 ... Roller 52 ... Cutting blade 100 ... Solar cell module 110 ... Wiring material

Claims (4)

A solar having a first solar cell provided with a connection electrode for connecting a wiring material on the light incident side and a second solar cell provided with a connection electrode for connecting the wiring material on the light incident side A battery module,
The first solar cell and the second solar cell are electrically connected to each other by the wiring member,
One end of the connection electrode is a solar cell module having a tapered shape.   The solar cell module according to claim 1, wherein the tapered end portion has a non-sharp shape.   The solar cell module according to claim 2, wherein the other end portion side of the connection electrode has a rectangular shape. The solar cell module according to claim 2, wherein the other end portion side of the connection electrode has a tapered shape.

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