JP4642662B2 - Photovoltaic element - Google Patents

Description

  The present invention relates to a photovoltaic device, a photovoltaic device assembly, a photovoltaic device module, and methods for producing them. In particular, the present invention relates to a solar cell, a solar cell assembly, a solar cell module, and a method for manufacturing them, which are intended to generate electricity by light.

  It is well known that the use of metal wires as grid electrodes and busbar / interconnectors for solar cells leads to improved solar cell performance, but it is sufficient due to the difficulty of wiring metal wires at high speeds. Cost merit is not achieved and it has not spread.

  One of the reasons why high-speed wiring of metal wires to solar cells is difficult is that wire bonding technology that is prevalent in the semiconductor field cannot be used as existing high-speed wiring technology. Wire bonding is a technique suitable for wiring in a short distance such as between a lead frame and a chip electrode pad. Therefore, it is difficult to apply to a portion that needs to be wired over a long distance, such as a grid electrode of a solar cell. Also, metal wires that can be wire-bonded are generally expensive. When such metal wires are wired on the surface of a solar cell over a long distance, it is difficult to obtain a cost merit.

  For this reason, in Patent Documents 1 to 4, an adhesive coating layer is formed on a metal wire, a plurality of the metal wires are arranged in parallel, are stretched on the photovoltaic body, and are heat-pressed on the photovoltaic body. The slow wiring method is adopted.

  However, Patent Document 5 discloses an idea that can realize a sufficient cost merit even if a high-speed wiring of a metal wire is realized and an inexpensive metal wire is used for a grid electrode or a bus bar / interconnector. The idea is to form a sheet-like electrode body formed by weaving metal wires 10 and to bond it on the photovoltaic body 1 as shown in FIG. A mesh body made of a metal wire fabric is used in various fields such as a screen printing plate, a high-temperature gas filter, and an electromagnetic wave absorbing sheet. These are formed by an apparatus using an automatic loom in the textile industry. Therefore, it can be formed at a very high speed and in a large area. If the large-area and high-speed network is cut and bonded onto the photovoltaic element, the solar cell of FIG. 19 is completed. This can be said to be a very high-speed wiring method as compared with the wiring methods disclosed in Patent Documents 1 to 4.

JP 2004-134656 A Japanese Patent Laid-Open No. 2004-140024 Japanese Patent Laid-Open No. 3-6867 JP-A-8-46226 JP-A-6-151915

  However, the solar cell of Patent Document 5 has not been realized. The reason is that the joining of the metal wire 10 and the photovoltaic element 1 tends to be insufficient.

  The sheet-like electrode body of Patent Document 5 is a woven fabric as shown in FIG. 20a), and is basically composed of vertical fibers 12t and horizontal fibers 12y, and the two cross each other. The shape of the fabric is maintained by the frictional force of the portion where the vertical fibers 12t and the horizontal fibers 12y intersect. In order to sufficiently obtain this frictional force, it is necessary to apply a strong tension to each fiber so that the longitudinal fiber 12t and the transverse fiber 12y are pressed against each other at a portion where the longitudinal fiber 12t and the transverse fiber 12y intersect. Otherwise, the frictional force is reduced and the intersection is easily displaced, so that it is impossible to maintain the shape of the fabric. In order to apply a strong tension to each fiber, it is necessary to closely weave the longitudinal fibers 12t and the transverse fibers 12y. If the longitudinal fibers 12t and the transverse fibers 12y are closely woven, a strong tension is applied to each fiber in the weaving process as follows.

  FIG. 20b) shows a view of the loom from the side. First, a plurality of longitudinal fibers 12t are regularly and densely wound around a cylindrical part called a warp beam. Next, the plurality of longitudinal fibers 12t are pulled out from the warp beam, wound on a winding roll through a dropper and a heald, and stretched in the air. At this time, the plurality of vertical fibers 12t are stretched side by side in parallel. Then, the plurality of stretched vertical fibers 12t are regularly distributed up and down with a heald in the order in which they are arranged. The horizontal fiber 12y is passed through the gap between the upper vertical fiber 12t and the lower vertical fiber 12t, which are created by sorting up and down, and is fitted into the left gap in the drawing using a scissors. At this time, the transverse fibers 12y are substantially linear. In order to fit the next horizontal fiber 12y, when the vertical fibers 12t that have been distributed up and down are turned upside down by using a heald, the horizontal fibers 12y and the vertical fibers 12t that have been fitted first are shown in FIG. 20a). As shown in the cross-sectional view, it bends from a straight line to a wavy line. Therefore, the length of each fiber is increased by the amount of bending, and the tension of each fiber is increased by this elongation. When the longitudinal fibers 12t and the transverse fibers 12y are densely woven, the elongation increases when each fiber changes from a straight line to a wavy line, and therefore a stronger tension is applied to each fiber. In other words, in other words, the sheet-like electrode body 11 disclosed in Patent Document 5 is a woven fabric made of a metal wire, and in order to maintain the shape, the fibers forming the woven fabric are inevitably densely woven. It is necessary to be bent in a wavy line.

  Moreover, as shown in FIG. 20a), the sheet-like electrode body of Patent Document 5 is the simplest plain weave fabric among the fabrics. This is because in the process of weaving the woven fabric, when the vertical fibers 12t arranged in the air are regularly distributed up and down in order, the adjacent vertical fibers 12t are always arranged up and down alternately. In addition, it is woven by sorting up and down. Therefore, as shown in the cross-sectional view of FIG. 20a), the longitudinal fibers 12t are bent so as to sew between the transverse fibers 12y, and have a continuous wavy shape like a sine wave. Similarly, the transverse fibers 12y are bent so as to sew between the transverse fibers 12y, and have a continuous wavy shape like a sine wave.

  As a result, when such a net-like body is joined to the photovoltaic body, as shown in the AA ′ cross-sectional view of FIG. 19, the joining surface of the metal wire 10 and the photovoltaic body 1 is only the portion B in the figure. Become. This is almost a point contact and has a small bonding area. Therefore, both electrical joining and mechanical joining tend to be insufficient. If the electrical junction is insufficient, the series resistance component of the solar cell increases and the performance decreases. Moreover, if mechanical joining is insufficient, durability will fall and it will become impossible to maintain the stable performance over a long period of time. The AA ′ cross section is a cross section along the horizontal line 10b, but this situation is the same when viewed from the cross section along the vertical line 10a. Similarly to the horizontal line 10b, the joint surface between the vertical line 10a and the photovoltaic element is the same. However, it is close to point contact, and electrical and mechanical joints tend to be insufficient.

  By the way, as shown in FIG. 21, the space between the vertical lines 10a and the space between the horizontal lines 10b are increased to increase the aperture ratio of the mesh body, thereby increasing the bonding area between the horizontal line 10b and the photovoltaic element 1 on the bonding surface B. It is possible to enlarge it. However, in this case, since the tension between the vertical line 10a and the horizontal line 10b is easily loosened, the intersection is easily displaced. And a net-like body will lose shape easily.

  If the mesh body loses its shape, for one thing, productivity is significantly reduced. Moreover, the space | interval of the metal wire 10 becomes non-uniform | heterogenous and the problem that the performance of a solar cell falls also generate | occur | produces. This is because if the intervals between the metal wires 10 are not uniform, the current collection efficiency at the portion where the interval is wide is greatly reduced, whereas the current collection efficiency at the portion where the interval is wide is greatly reduced. This is because the performance of the solar cell is lowered. The current collection efficiency referred to here is a small Joule loss caused when a current generated in the photovoltaic element flows on the surface of the photovoltaic element toward the lattice electrode.

  Eventually, the interval between the vertical lines 10a and the interval between the horizontal lines 10b cannot be increased until a joining surface B having a sufficient area as shown in FIG. 21 is obtained.

  As described above, the solar cell of Patent Document 5 is in a situation where an increase in series resistance component due to insufficient electrical connection between the metal wire 10 and the photovoltaic element 1 and a decrease in performance are likely to occur. In addition, due to insufficient mechanical joining between the metal wire 10 and the photovoltaic element, it was difficult to exhibit stable performance over a long period of time.

  Therefore, the present invention dramatically improves the performance and durability of a photovoltaic element of a type in which a sheet-like electrode body having a metal wire as a constituent element is bonded onto the photovoltaic element, and is extremely low in price, An object of the present invention is to provide a photovoltaic device which can be produced at high speed and has high performance and durability.

  That is, the photovoltaic element of the present invention is characterized in that a sheet-like electrode body obtained by sewing a metal wire on the surface of a translucent sheet and a photovoltaic body are joined.

  The photovoltaic element assembly of the present invention is characterized in that a plurality of photovoltaic bodies are connected in parallel by a sheet-like electrode body in which a metal wire is sewn on the surface of a translucent sheet. .

  Further, another photovoltaic element assembly of the present invention comprises a plurality of photovoltaic elements or photovoltaic element assemblies by a sheet-like electrode body in which a metal wire is sewn on the surface of a translucent sheet. It is characterized by being connected in series.

  In addition, the method for producing a photovoltaic element of the present invention includes a step of joining a photovoltaic element and a sheet-like electrode body in which a metal wire is sewn on the surface of the translucent sheet. To do.

  The method for producing a photovoltaic element module according to the present invention includes a step of joining a photovoltaic element to a sheet-like electrode body in which a metal wire is sewn on a surface of a translucent sheet, and the photovoltaic element. And the step of sealing with transparent resin are performed in the same step.

  ADVANTAGE OF THE INVENTION According to this invention, the performance and durability of a photovoltaic element of the type which joins the sheet-like electrode body which consists of metal wires on a photovoltaic body are improved dramatically. This also makes it possible to provide a photovoltaic device that can be produced at a very low cost and at high speed, and that has higher performance and higher durability.

  Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

<Embodiment 1>
FIG. 1 is a schematic view schematically showing an example of the photovoltaic element of the present invention.

  FIG. 1a) is a view showing a sheet-like electrode body, a left view is a bottom view, and a right view is a top view. The sheet-like electrode body 11 of this example is obtained by sewing the metal wire 10 on the lower surface of the translucent sheet 22.

  FIG. 1b) shows a photovoltaic element. The photovoltaic element of this example is completed by joining both the upper surface of the photovoltaic body 1 and the lower surface of the sheet electrode body 11 together. Then, the electric power generated by the light incident on the photovoltaic body 1 is extracted through the metal wire 10 of the sheet electrode body 11 to the outside of the photovoltaic element.

  FIG. 1c) is a sectional view taken along the line AA 'of FIG. 1b). According to this example, the junction distance B between the metal wire 10 and the photovoltaic element 1 can be increased. For this reason, the joining is a joining by wire, and in Patent Document 5, the joining portion between the metal wire and the photovoltaic element is joining at a point, but the joining area can be remarkably increased.

  In this example, when the bonding area between the metal wire 10 and the photovoltaic element 1 is increased, the bonding resistance between the sheet-like electrode body 22 and the photovoltaic element 1 is decreased, and the performance of the photovoltaic element is improved. improves. Further, the bonding strength is increased and the reliability is improved. That is, the performance and reliability problems that occur in the case of the photovoltaic element disclosed in Patent Document 5 are solved.

  In addition, since the fixation with the translucent sheet | seat 22 of the metal wire 10 becomes loose when the joining distance B is extremely long, when joining the sheet-like electrode body 11 and the photovoltaic body 1, the metal wire 10 is It becomes easy to bend. If the metal wire 10 is bent, the current collection efficiency of the grid electrode (metal wire 10) is lowered, and the performance of the photovoltaic device is lowered, which is not preferable. For a metal wire having a thickness of about 10 μm to 1 mm, the pitch (bonding distance) B is preferably several mm to several tens mm.

  The sewing method of the translucent sheet 22 and the metal wire 10 in this example is a method classified as hand-sewing in JIS L0120, and is difficult to sew with a known sewing machine. However, it can also be formed at high speed by mechanizing the method as shown in FIG. That is, as shown in FIG. 2a), a plurality of metal wires 10 passed through the sewing needle are arranged and stretched, the translucent sheet 22 is folded, and the ends of the folds are sewn so as to squeeze with the sewing needle. Next, as shown in FIG. 2b), when the folded translucent sheet is spread, the sheet-like electrode body of FIG. 1 is completed.

  FIG. 3 is an example in which the sewing method in FIG. 1 is changed. FIG. 3 is a cross-sectional view of the photovoltaic element, corresponding to FIG. 1c). As shown in FIG. 3, it is preferable that the metal wire 10 is sewn so as not to be exposed on the upper surface of the translucent sheet 22 in that the joining area between the metal wire 10 and the photovoltaic element 1 can be increased. Comparing FIG. 1c) and FIG. 3, the size of one seam G is smaller in FIG. Due to this, it can be seen that in the case of FIG. 3, the bonding distance B is increased as compared with the case of FIG. 1. Furthermore, when the translucent sheet 22 functions as a sealing layer of the photovoltaic element, the sewing method as shown in FIG. 3 is preferable. This is because, in the case of FIG. 1, the metal wire 10 is exposed on the upper surface of the translucent sheet 22, and thus a sealing layer is further required on the upper part.

<Embodiment 2>
FIG. 4 is a schematic view schematically showing another example of the photovoltaic element of the present invention. This example is different from the first embodiment in that the metal wire 10 is sewn to the translucent sheet 22 by the sewing thread 14.

  FIG. 4 a) is a diagram showing a sheet-like electrode body, the left figure is a bottom view, and the right figure is a top view. In the sheet-like electrode body 11 of this example, the metal wire 10 is sewn to the lower surface of the translucent sheet 22 by sewing with a sewing thread 14.

  FIG. 4b) shows a photovoltaic element. The photovoltaic element of this example is completed by joining both the upper surface of the photovoltaic body 1 and the lower surface of the sheet electrode body 11 together.

  4c) are cross-sectional views taken along the line BB 'in FIG. 4a) and along the line AA' in FIG. 4b). In this example, similarly to the first embodiment, the bonding distance B between the metal wire 10 and the photovoltaic element 1 can be increased. In particular, if a known lockstitch sewing machine is used, the length can be easily increased to about several tens of millimeters. For this reason, the joining is a joining by wire, and the joining area is remarkably increased.

  Furthermore, this example is superior to the first embodiment in that the junction area between the metal wire 10 and the photovoltaic element 1 can be increased.

  In the first embodiment, the metal wire 10 penetrates through the translucent sheet 22 to form a seam. Therefore, the metal wire 10 floats from the surface of the photovoltaic element 1 at the seam G portion. Although it is possible to make the seam G smaller as shown in FIG. 3, as the seam G is made smaller, the operation of forming the seam becomes difficult and the productivity is also lowered. However, when the metal wire 10 is sewn with the sewing thread 14 as in this example, the length that the metal wire 10 floats from the surface of the photovoltaic element 1 is sewn as indicated by G in FIG. It can be easily suppressed to the thickness of the thread. Therefore, the present example in which the metal wire 10 is sewn with the sewing thread 14 has an effect of increasing the bonding area between the metal wire 10 and the photovoltaic element 1.

  Furthermore, this example is superior to Example 1 in that higher productivity can be obtained.

  If the translucent sheet 22 and the metal wire 10 are sewn with only the metal wire 10 as in the first embodiment, the metal wire 10 must pass through the translucent sheet 22 without fail. When penetrating the metal wire 10 through the translucent sheet 22, it is necessary to apply a large tension to the metal wire 10 because there is a frictional force received from the inner surface of the through hole. Furthermore, a large bending stress is applied to the metal wire 10 from the inner surface of the through hole due to the deformation of the through hole due to the deformation of the translucent sheet 22. Since the metal wire 10 is made of metal, the region showing elasticity against stress is narrow, and plastic deformation is likely to occur. If a large plastic deformation occurs in the metal wire 10 and an extreme elongation, kink, breakage or the like of the metal wire occurs, the current collection efficiency of the grid electrode is lowered, leading to a decrease in the performance of the photovoltaic device. Therefore, if a sheet-like electrode body like the first embodiment is formed at high speed, various restrictions are added.

  However, in this example, it is the sewing thread 14 that penetrates the translucent sheet 22. For this reason, if the well-known thread | yarn which is hard to plastically deform and has moderate elasticity is used for the sewing thread | yarn 14, said problem can be avoided. Therefore, high-speed molding of the sheet-like electrode body is easier than in the first embodiment, the metal wire 10 can be sewn to the translucent sheet 22 at high speed, and higher productivity can be obtained.

  FIG. 5 shows a process of sewing one stitch of a known lockstitch sewing machine. FIG. 5 shows only a part of the sewing machine (sewing needle 23 and shuttle 24). A bobbin around which a bobbin thread 26 is wound is stored in the hook 24. In FIG. 5a) the sewing needle 23 is at the lowest point. In this state, the needle thread 25 passed through the needle hole formed in the needle tip of the sewing needle 23 is drawn under the fabric 27. When the sewing needle 23 rises slightly toward FIG. 5 b), the needle thread 25 drawn under the fabric 27 is loosened. The sword 28 of the rotating hook 24 hooks the slack of the needle thread 25. 5c) to 5g), the shuttle 24 further rotates, so that the sword tip 28 draws the needle thread 25 further under the fabric 27 to form a large loop. At the same time, the hook 24 in which the bobbin wound with the bobbin thread 26 is housed in the loop. Finally, in FIG. 5h), when a balance (not shown) pulls up the needle thread 25, the needle thread 25 that has come out under the fabric is pulled back upward.

  The sheet-like electrode body 11 of this example can be formed more easily and at a higher speed than that of the first embodiment by using such a known book-stitch sewing machine. For example, if the stitch pitch is 20 mm and the sewing speed is 2,500 times per minute, it is possible to wire metal wires at 50 m per minute.

  The sewing thread 14 is preferably transparent. If a transparent material is used, light incident on the photovoltaic device is not blocked, so that the performance of the photovoltaic device is improved compared to the case where an opaque material is used.

  In the case of this example, it is preferable to control the amount of penetration of the metal wire 10 into the translucent sheet 22 in the portion indicated by C in FIG. In FIG. 5 d), the upper thread (needle thread) 25 is pulled up to the middle in the thickness direction of the fabric 27. Accordingly, the lower thread (bobbin thread) 26 has penetrated to the middle of the cloth 27 in the thickness direction. In the case of this example, as shown in the BB ′ cross-sectional view of FIG. 4 c), the lifting amount of the metal wire 10 corresponding to the lower thread is controlled to be several times the thickness of the sewing thread 14. Thus, it is preferable to control the pulling amount of the metal wire 10 to be several times the thickness of the sewing thread 14. This is because the distance through which the power of the photovoltaic element is transmitted through the metal wire 10 is prevented from becoming longer, and the current collection efficiency of the grid electrode is improved. Further, if the amount of the metal wire 10 drawn into the translucent sheet 22 is suppressed and the height from the light incident surface of the photovoltaic element to the upper surface of the metal wire 10 is lowered, the lattice electrode is placed on the photovoltaic element. It is possible to reduce the shadow formed. Also in this sense, it is preferable to suppress the amount of drawing the metal wire 10. Further, if the amount of drawing the metal wire 10 is suppressed, the kink is prevented from being generated in the portion where the metal wire 10 is drawn, and the metal wire 10 is hardly broken. Therefore, it is preferable in terms of reliability. However, if the pull-in amount of the metal wire 10 is extremely small, the sewing thread 14 in the portion indicated by C in FIG. 4c) BB ′ sectional view protrudes downward on the lower surface of the sheet-like electrode body 11. Therefore, it becomes an obstacle when the sheet-like electrode body 11 is joined to the photovoltaic body 1, and the bonding distance B between the metal wire 10 and the photovoltaic body 1 may be shortened. Therefore, it is preferable to draw the metal wire 10 so that the transparent yarn 14 does not protrude as shown in FIG.

  The seam pitch P shown in FIG. 5d) can be increased by adjusting a feed mechanism of the fabric 27 (not shown). In this example, B in FIG. 4c) corresponds to this pitch P. By increasing the pitch P, B becomes longer and the junction area between the metal wire 10 and the photovoltaic element 1 can be increased.

<Embodiment 3>
FIG. 6 shows another example in which the metal wire 10 is sewn to the translucent sheet 22 by the sewing thread 14.

  FIG. 6 a) is a diagram showing a sheet-like electrode body, the left figure is a bottom view, and the right figure is a top view. In the sheet-like electrode body 11 of this example, the metal wire 10 is used as a decorative thread by sewing a sewing thread 14 in a crossing direction on the metal wire 10 placed side by side on the surface of the translucent sheet 22. The light transmitting sheet 22 is sewn. The metal wire 10 is sewn to the lower surface of the translucent sheet 22 by the main sewing using both the needle thread, the bobbin thread and the sewing thread 14.

  FIG. 6b) shows a photovoltaic element. The photovoltaic element of this example is completed by joining both the upper surface of the photovoltaic body 1 and the lower surface of the sheet electrode body 11 together. 6c) is a cross-sectional view taken along the line AA 'of FIG. 6b). In this example, similarly to the second embodiment, the junction distance B between the metal wire 10 and the photovoltaic element 1 can be increased.

  By the way, in Embodiment 2, the metal wire 10 itself functions as a sewing thread for maintaining the seam. If there is no metal wire 10, no seam is formed, and the sewing thread 14 is translucent. It leaves the seat. On the other hand, in the case of this example, the seam of the sewing thread 14 is maintained even without the metal wire 10. In this way, a thread that is inserted as a decoration in the seam without directly contributing to the maintenance of the seam is called a decorative thread. According to JIS L0120, such a decorative thread is inserted in the stitch type of class 600. It is necessary to apply a tension for maintaining the seam to the entire sewing thread to the sewing thread for maintaining the seam, and due to this tension, a large friction or stress is easily applied to a portion where the sewing thread intersects. On the other hand, even if the decorative thread to be inserted for decoration is loose, the seam is retained, so that it is not necessary to apply tension as much as the sewing thread. For this reason, when the metal wire 10 is sewn to the translucent sheet with the sewing thread 14, the metal wire 10 can be sewn as a decorative thread to stretch, bend, kink, It is possible to prevent the occurrence of breakage, which is preferable in terms of improving the performance of the photovoltaic element and reliability.

  In addition, the metal wire 10 and the translucent sheet 22 are sewn by sewing the sewing thread 14 in the direction intersecting with the metal wire 10 as in this example, thereby increasing the productivity. Highly preferred above. This is because the distance for sewing the sewing thread 14 is shortened compared to the case of sewing the sewing thread 14 of the metal wire in the same direction as the metal line 10 as in the second embodiment, and the material used and the sewing This is because it takes less time.

  FIGS. 7 and 8 show another example in which the sewing thread 14 is sewn in the direction intersecting the metal wire 10. 7 and 8 show only a bottom view and a top view of the sheet-like electrode body.

  As shown in FIG. 7 a), there may be a part where the sewing thread 14 is sewn in parallel with the metal wire 10. In this case, as shown in FIG. 6, there is no need to interrupt the sewing process and perform thread trimming, so that the sewing thread 14 can be continuously sewn.

  As shown in FIG. 7 b, there may be a part where the sewing thread 14 is sewn so as to cross the metal wire 10 obliquely. The sewing thread 14 is sewn while moving the translucent sheet 22 on which the metal wire 10 is placed upward or downward in the figure under the sewing head that periodically reciprocates in the left-right direction in the figure. Is possible. As shown in the enlarged view, the sewing thread 14 may be sewed by switching back to the portion where the sewing thread 14 has been sewn once to reinforce the sewing strength.

  FIG. 7 c) shows a grid made of thick metal wires 10 a and a grid made of thin metal wires 10 b placed on the translucent sheet 22 so as to be orthogonal to each other in this order. These points are sewn to the translucent sheet 22. If necessary, two or more kinds of metal wires 10 may be sewn to the sheet-like electrode body 11 in this way. By doing so, a sheet-like electrode body with high current collection efficiency can be easily formed. In the example of FIG. 7c), the thin metal wire 10b functions as a grid electrode, and the thick metal wire 10a functions as a bus bar. Therefore, the electric power generated by the photovoltaic element is first transmitted through the grid electrodes made of the thin metal wires 10b, gathered in the bus bars made of the thick metal wires 10a, and taken out through the bus bars. Therefore, by adjusting the thickness and interval of the thin metal wire 10b and the thick metal wire 10a according to the performance of the photovoltaic element, an electrode with high current collection efficiency can be obtained. Here, as the two or more kinds of metal wires, metal wires having different thicknesses as described above may be used, or metal wires having different materials may be used. You may use the metal wire from which thickness and kind differ.

  FIG. 8 shows an example of sewing using a plurality of sewing heads. These can be formed very quickly using, for example, the apparatus shown in FIG. A bobbin around which a metal wire 10 is wound is set on the left part of the apparatus shown in FIG. From there, a plurality of metal wires 10 are arranged in the right direction in the figure and pulled out in the horizontal direction. Separately, the translucent sheet 22 is drawn rightward from the roll of the translucent sheet 22 in the same manner as the metal wire 10. A plurality of the above-described metal wires 10 drawn out side by side are placed on the drawn translucent sheet 22 and then inserted into a transport roll. Further, a sewing thread (not shown) is sewed onto the translucent sheet 22 from above the metal wire 10 by the sewing device on the right side of the transport roll, and the metal wire 10 and the translucent sheet 22 are sewn. . The metal wire 10 integrated in this way and the translucent sheet 22 are divided by a dividing press machine to obtain the sheet-like electrode body 11.

  The sewing locations are not limited to those shown in FIGS. What is necessary is just to sew a key point so that the metal wire 10 may not bend when joining the translucent sheet | seat 11 and the photovoltaic body 1. FIG.

<Embodiment example 4>
FIG. 10 a) is a diagram showing a sheet-like electrode body, the left figure is a bottom view, and the right figure is a top view. The sheet-like electrode body 11 of this example is different from the third embodiment in that the sewing thread 14 is sewed by single-ring stitching composed of a stitch type 101 described in JIS L0120 and a component called looping.

  FIG. 10b) is a diagram showing a photovoltaic element. The photovoltaic element of this example is completed by joining both the upper surface of the photovoltaic body 1 and the lower surface of the sheet electrode body 11 together. FIG. 10c) is a sectional view taken along the line AA 'of FIG. 10b). In this example, similarly to the third embodiment, the junction distance B between the metal wire 10 and the photovoltaic element 1 can be increased.

  The stitch form 101 and the single ring stitch are formed by a known single ring stitch sewing machine shown in FIG. FIG. 11 illustrates the process of sewing one stitch of a known single-ring stitch machine. FIG. 11 shows only a part of the sewing machine (sewing needle 23 and looper). Unlike the main sewing machine shown in FIG. 5, only the sewing thread (needle thread) 25 is used and there is no bobbin thread. In FIG. 11a) the sewing needle 23 is in the middle of lowering. Further, the fabric 27 is also moving to the left by one stitch pitch. In addition, the looper is in a state of passing through the first loop. In FIGS. 11 a) to b), the fabric 27 moved by one stitch pitch stops, and the sewing needle 23 penetrates the fabric 27 while drawing the needle thread 25 that has passed through the needle hole under the fabric 27. In FIG. 11 b), the sewing needle 23 is slightly raised from the lowest point, and the second loop is formed by the needle thread 25 remaining under the fabric 27. The tip of the rotating looper passes through this second loop. From FIG. 11b) to c), the second loop is passed through the first loop by the looper. As shown in FIGS. 11c) to 11d, the needle 23 is raised, the looper is further rotated, and the second loop is enlarged. As a result, the first loop is small and one seam is completed. In order to further increase the sewing strength, it is possible to use double ring stitching instead of single ring stitching.

  FIG. 12 shows basic components constituting the seam. FIG. 12a) shows a component called cross thread racing. This is a component in which the needle thread 25 passes through the loop formed by the other thread, or the other thread passes through the loop formed by the needle thread 25, and the needle thread 25 and the other thread intersect. . The other thread lacing is a basic constituent element of the main sewing shown in the third embodiment, and is formed as shown in FIG. 5, for example. In FIG. 5, the bobbin around which the bobbin thread (other thread) is wound passes through the loop formed by the needle thread 25. In order to form the other yarn lacing in this way, it is necessary that the other yarn (bobbin) passes through the loop formed by one yarn.

  On the other hand, FIG. 12b) shows a component called looping. This is a component that loops through the loop. The left figure is called self thread looping, and the other loop formed by the needle thread 25 (self thread) passes through the loop formed by the needle thread 25. The right figure is called other thread looping, and the loop formed by the other thread passes through the loop formed by the needle thread 25 or the loop formed by the other thread is the loop formed by the other thread. Go through the inside. The self-looping is a basic component of the single ring sewing of this example, and is formed as shown in FIG. 11, for example. In FIG. 11, the second loop formed by the looper passes through the first loop formed by the needle thread 25. In general, in order to form a looping, only the thread loop passes through the loop, so that it is not necessary for the entire thread (bobbin) to pass through unlike the racing.

  Except for the sewing method classified as hand-sewn in JIS L0120, the stitches of known sewing machines are basically formed by these lacing or looping. The stitch types 101 to 108 of JIS L0120 consist of own yarn looping. Similarly, 301 to 327 are types including other yarn racing. 401 to 417, 501 to 521, and 601 to 609 are due to other yarn looping.

  The sewing method of the metal wire 10 and the translucent sheet 22 is preferably a form formed by looping among these stitch forms. This is because if the sewing method is based on looping, the productivity of the sheet-like electrode body 11 is significantly improved as compared with the sewing method based on racing. In order to perform looping as described above, it is basically unnecessary to pass a bobbin wound with the whole thread through the loop. For this reason, there is no restriction on the size of the bobbin around which the yarn is wound. For this reason, it is possible to drastically reduce the replacement frequency of the bobbin, and the productivity is increased. On the other hand, in the case of racing in which the bobbin passes through the loop, if the bobbin is small, a device that can be sewn at a high speed can be formed, but the frequency of bobbin replacement increases. On the other hand, if the bobbin is large, it is difficult to rotate the shuttle 24 of FIG. 5 at a high speed, so that the sewing speed decreases. Therefore, the size of the bobbin is limited.

  For the above reason, in particular, in the method of continuously sewing the metal wire 10 on the roll-shaped translucent sheet 22 as shown in FIG. 9, sewing by looping is suitable. In order to increase the productivity of the apparatus as shown in FIG. 9, chain stitching using a plurality of needles is more suitable. For example, there is an apparatus that industrially arranges about 30 needles and continuously performs the stitch format 401 of JIS L0120 in parallel. By using such an apparatus, high productivity can be obtained.

  FIG. 13 shows a method of simultaneously performing the stitch format 101 (single ring stitching) with ten needles arranged at equal intervals. FIG. 13 shows only the needle thread 25, and the cloth, needle, looper, etc. are not shown. FIG. 13 is a perspective view, and FIG. 13a) shows only a single needle thread 25 extracted virtually. Originally, as shown in FIG. The two needle threads are linked to each other in some places. This sewing method basically consists of a single ring stitch shown in the enlarged view of FIG. 13a). However, unlike ordinary single-ring stitches, each time two stitches are sewn, the needle stab position is moved by a fixed distance (distance indicated by d in the figure) in the direction perpendicular to the basic sewing direction indicated by arrow D. Is. FIG. 13a) shows a state in which sewing has been carried out 17 stitches from the start of sewing by changing the sewing direction diagonally at the portion indicated by t while sewing in the basic sewing direction indicated by arrow D. ing. If the sewing method of FIG. 13a) is simultaneously performed with ten needles arranged in parallel and the needle threads are linked to each other, the sewing method of FIG. 13b) is possible. If the roll unwinding direction of the translucent sheet 22 in FIG. 9 and the direction indicated by the arrow D in FIG. 13 coincide with each other by such a method, it is possible to sew while constantly rotating the roll. Therefore, productivity is high.

<Modification>
This invention is not limited to the surface of the photovoltaic body which joins a sheet-like electrode body. The surface to which the sheet-like electrode body is bonded may be the light incident surface, the non-light incident surface, or both of the photovoltaic element. In any case, the effects of the invention can be obtained. However, it is necessary to select a metal wire sewing method suitable for each of the light incident surface and the non-light incident surface.

  When joining to a non-light-incident surface, the sewing method which can make the Joule loss which generate | occur | produces when an electric current flows into the sheet-like electrode body 11, a production cost, and material cost small in good balance is desirable.

  On the other hand, when bonding to the light incident surface, by adjusting the thickness, spacing, etc. of the metal wires constituting the sheet electrode body, the Joule loss due to the current flowing through the sheet electrode body and the sheet electrode body is lightened. It is necessary to balance with the shadow loss due to blocking. That is, it is necessary to adjust the thickness, interval, and the like of the metal wires constituting the sheet-like electrode body to optimum values in accordance with the power generation capacity of the photovoltaic body.

  Further, in common with the sheet-like electrode body of the present invention, a part thereof may have a part that is sewn differently from the other part, and if necessary, a reinforcing material such as polycarbonate fiber. May be sewn. Further, a metal foil or the like may be sewn or joined to the sheet-like electrode body.

  Further, in order to serialize the photovoltaic bodies, a sheet-like electrode body having a series portion in which a metal wire protrudes from the surface of the translucent sheet is formed, and this photovoltaic electrode body is used as one photovoltaic body. The series part may be joined to the other photovoltaic element.

  The meaning of terms will be explained below.

<Metal wire 10>
Although this invention is not limited by the kind of metal wire, the following are mentioned as a metal wire.

  Metal wires are industrially stably supplied as wires. As a production method thereof, a method obtained from a base material through a wire drawing step is common. The wire drawing process may be performed by applying heat to the base material, or may be performed by drawing through a die. An annealing step may be provided in addition to the wire drawing step. There is also a method of forming a wire by slitting a foil material formed by rolling or electrolysis. In this case, the cross section is rectangular.

  As the material of the metal wire, for example, materials such as copper, silver, gold, platinum, aluminum, molybdenum, and tungsten are preferable because of their low specific resistance. Among them, copper is most used because of its low electrical resistance and low cost. The metal wire may be an alloy of these metals.

  A thin metal layer or resin layer may be formed on the surface of the metal wire for the purpose of bonding the photovoltaic element and the metal wire, preventing corrosion, preventing oxidation, improving electrical conduction, etc. is there. Moreover, the antirust process may be performed. As the metal layer formed on the surface, for example, a precious metal that is not easily corroded such as silver, palladium, an alloy of silver and palladium, gold, or a metal having good corrosion resistance such as nickel, tin, or solder is used. Among these, gold, silver, tin, and solder are preferable because they are not easily affected by humidity. As a method for forming the metal layer, for example, a plating method or a cladding method is generally used. The thickness of the conductive resin that covers the metal wire is determined as desired. For example, when the metal wire has a circular cross section, a thickness of 1% to 10% of the diameter is suitable. The specific resistance of the metal layer and the resin layer is preferably 10 Ωcm or less in consideration of the effects of electrical continuity, corrosion resistance, and metal layer thickness. Specifically, a sintered silver paste in which silver particles and glass frit, an organic vehicle, etc. are mixed, a resin-based conductive paste in which silver particles or rust-proof copper particles are dispersed in a thermoplastic or thermosetting resin, Examples thereof include a carbon paste in which graphite is dispersed instead of silver, or a low-temperature firing type silver paste mainly composed of a solvent and silver oxide.

  The cross-sectional shape of the metal wire is preferably a circle, but may be a rectangle, a triangle, or the like, and is appropriately selected as desired. The diameter of the metal wire is selected so as to minimize the entire loss such as Joule loss and shadow loss. For example, a copper wire having a diameter of 25 μm to 1 mm is often used. More preferably, an efficient photovoltaic device can be obtained by setting the thickness to 25 μm to 200 μm. If the thickness is smaller than 25 μm, the metal wire is easily cut, making it difficult to manufacture, and increasing electric loss. Further, when the thickness is 200 μm or more, shadow loss increases, or unevenness of the surface of the photovoltaic element increases, and when filling the element surface with resin, a filler such as EVA may have to be thickened. is there.

<Translucent sheet 22>
The translucent sheet is a sheet-like member on which a metal wire is sewn and is transparent. As a condition desired for the translucent sheet, first, it is possible to make the photovoltaic element transparent when it is resin-sealed. This is because the photovoltaic element is generally used in a state sealed with resin. Regarding the transparency, the total light transmittance is required to be 90% or more in the state where the translucent sheet is bonded to the photovoltaic element and the resin is sealed, and more preferably 95% or more. This is to effectively use the power generation performance of the photovoltaic element.

  In order to set the total light transmittance to 90% or more, it is effective that the refractive indexes of the translucent sheet and the sealing resin are substantially equal. In general, since the sealing resin has a refractive index of about 1.4 to 1.6, it is desirable that the refractive index of the material constituting the translucent sheet is also 1.4 to 1.6. Furthermore, in order to set the total light transmittance to 90% or more, it is preferable that the interface between the sealing resin and the translucent sheet is not perpendicular to the light incident direction but inclined. This is because the light reflected at the interface between the sealing resin and the translucent sheet can be totally reflected at the interface between the sealing resin and the air and incident again on the photovoltaic element. Therefore, the average inclination angle of the interface between the sealing resin and the translucent sheet needs to be 20 degrees or more, and more preferably 40 degrees or more. In order to increase this average inclination angle, it is effective to form grooves on the surface of the translucent sheet by a process such as scribe or press molding, or to form a non-uniform film by a process such as vapor deposition, sputtering, or plating. Is.

  Moreover, in order to set the total light transmittance to 90% or more, an air layer remains at the interface between the sealing resin and the translucent sheet during resin sealing, thereby preventing the reflectance of incident light from increasing. There is a need. For this reason, it is desired that the surface of the translucent sheet has a characteristic that the sealing resin can easily permeate in detail. In other words, in the sealing process, it is desirable that the liquid resin has high wettability with respect to the translucent sheet surface and that the translucent sheet surface does not have a fine structure through which the resin cannot penetrate. Specifically, the contact angle between the resin and the translucent sheet is desirably 90 ° or less, and it is preferable that the translucent sheet does not have a fine gap on the order of several μm.

  Furthermore, as a second condition desired for the translucent sheet, it is possible to easily penetrate the sewing needle. This is because when the translucent sheet has extreme hardness and elasticity, it is difficult to penetrate the sewing needle and the productivity of the photovoltaic element is lowered. Furthermore, the needle thread may break due to frictional heat between the sewing machine needle and the translucent sheet.

  As a translucent sheet satisfying the above-mentioned desired conditions, ethylene vinyl acetate copolymer (EVA), ethylene methacrylic acid copolymer (EMAA), ethylene methyl acrylate copolymer (EMA), ethylene ethyl acrylate copolymer Examples thereof include a resin sheet made of a polyolefin resin such as coalescence (EEA) and butyral resin, a urethane resin, a silicone resin, and a fluororesin. In particular, EVA and EMAA, which are general sealing resins for solar cell modules, are suitable in terms of transparency. These resins are preferably formed into a sheet shape using a known roll molding machine or an extrusion molding machine and used as a translucent sheet. The thickness of the sheet can be appropriately selected depending on the thickness of the metal wire, sewing thread, sewing needle, strength, etc., but a thickness of about 0.01 to 1 mm is preferable. Further, it is also effective to make the sheet a net-like body by making a large number of pores in the sheet so that the sewing needle can easily penetrate.

  Furthermore, the cloth which consists of a fiber is mentioned as a translucent sheet | seat with easy sewing. This is because the cloth has an infinite number of gaps through which the sewing needle penetrates, and therefore resistance to penetration of the sewing needle is extremely small. Examples of such a fabric include a woven fabric and a knitted fabric composed of yarns formed by twisting a plurality of fibers, but a nonwoven fabric composed of transparent single fibers is preferable. One reason is that the fiber density of the nonwoven fabric is smaller than that of the woven fabric or knitted fabric, and the resistance when the sewing machine needle penetrates is extremely small. Also, unlike woven fabrics and knitted fabrics, which consist of yarns in which a plurality of fibers are twisted together and have fine gaps in the order of μm between the fibers, the nonwoven fabrics are made of single fibers, the gaps between the fibers are large, and the sealing resin is It is also because it is easy to impregnate and it is easy to ensure the aforementioned transparency. In particular, a glass nonwoven fabric made of glass fibers is most suitable because it has a high heat resistant temperature and can be used even when the above-described sintered conductive paste is used, and also has sufficient weather resistance and strength. The cross section of the fibers constituting these fabrics is often circular, but triangular, rectangular, or polygonal cross sections may be used in order to enhance the resin impregnation property.

<Sewing thread>
It is a thread for sewing a metal wire to a translucent sheet by sewing to the translucent sheet. As described above, those which are difficult to plastically deform and have moderate elasticity are preferable. In particular, when used as a needle thread of a known sewing machine, excellent elasticity is required. This is because strong tension and bending stress are applied to the needle thread when the sewing needle is passed through the cloth, when a loop is formed in the needle thread, and when the needle thread is pulled up with a balance. In order to prevent the needle thread from being plastically deformed by this tension or bending stress and extending or kinking in the needle thread, the needle thread is required to have excellent elasticity. A known sewing thread can be cited as such a material having elasticity. Among these, nylon, polyester, acrylic, urethane, and the like are preferable as the resin fiber. Further, long glass fibers are also preferable because they have moderate elasticity.

  Further, the sewing thread is preferably transparent. Generally, a photovoltaic element is used in a state of being sealed with a resin. If the sewing thread is transparent when the photovoltaic element is resin-sealed, it is possible to prevent loss due to the shadow formed on the light incident surface of the photovoltaic element by the sewing thread. That is, any sealing resin that has good surface wettability and almost no difference in refractive index can be used. What gave surface treatment in order to improve the impregnation property of resin is suitable. Moreover, you may use the translucent member from which a warp differs, and the translucent member from which a kind differs as needed. Further, the cross-sectional shape may be a circle, a triangle, a rectangle, or the like.

<Photovoltaic body 1>
It has the effect | action which converts the energy of the incident light into electric power. Although this invention is not limited by the kind of photovoltaic body, the following are mentioned as a photovoltaic body. Known is a photovoltaic layer alone, or a composite of a photovoltaic layer and a substrate for maintaining the shape of the photovoltaic layer, an electrode layer for passing current, a layer for reflecting light, etc. is there.

  Most often, the photovoltaic layer consists of a semiconductor junction. Semiconductors are broadly divided into silicon and compound semiconductors represented by gallium arsenide and cadmium sulfide. Further, in terms of the band structure of the junction, a pn junction type that is a simple junction between the same type of p-type semiconductor and an n-type semiconductor, a heterojunction type that includes junctions of different semiconductors with different forbidden bands, and a semiconductor-metal Schottky barrier. Classified into types. The crystal structure is classified into a crystal system, a polycrystal system, a thin film microcrystal system, and a thin film amorphous system. In terms of the layer structure, a single layer composed of a single junction layer, a tandem layer formed by stacking two junction layers in series, and a triple layer including three layers are well known.

  As the thin film substrate, either a conductive substrate or an insulating substrate can be used. A metal substrate such as stainless steel or aluminum is suitable as the conductive substrate. Examples of the insulating substrate include a substrate made of glass, ceramic, and resin.

When the photovoltaic element is a thin film type, it is preferable to form a transparent conductive oxide layer such as ITO or Sn ₂ O ₃ for the purpose of improving the conductivity of the light incident side surface. When the photovoltaic element is a semiconductor substrate system, a silicon oxide film or a nitride film is often formed on the light incident surface for the purpose of preventing reflection of incident light and passivation of the surface. A layer having high reflectivity and high conductivity with respect to sunlight such as silver or aluminum is used on the surface on the light incident side of the semiconductor substrate system.

<Bonding of sheet electrode body and photovoltaic body>
What is necessary is just to select suitably the joining method of a sheet-like electrode body and a photovoltaic body with a photovoltaic body and a metal wire. For example, the joining method shown in FIG. In FIG. 14, the sheet-like electrode body shows only the metal wire 10, and the translucent sheet is not shown.

  In FIG. 14 a), an adhesive layer 10 h is applied in advance to the surface of the metal wire 10 s and is bonded onto the photovoltaic element 1. A sheet-like electrode body in which a metal wire 10s previously coated with an adhesive layer 10h is sewn may be formed and joined to the photovoltaic element 1, or a sheet-like electrode in which the metal wire 10s is sewn first. The body may be formed, and then the adhesive layer 10 h may be formed and bonded onto the photovoltaic body 1. When the photovoltaic element is formed by laminating a thin film semiconductor layer and a transparent electrode layer on a substrate, a conductive paste such as a resin-based silver paste, carbon paste, or ITO paste can be used as the adhesive layer 10h. When the photovoltaic element is made of a single crystal or polycrystalline semiconductor substrate, a passivation layer made of silicon nitride is generally formed on the surface. Therefore, it is preferable to select a sintered silver paste that can fire through the passivation layer as the adhesive layer 10s.

  FIG. 14 b) shows a case where a printed electrode 15 on which a conductive paste is printed is formed on the photovoltaic body 1, and the metal wire 10 is joined on the photovoltaic body 1 by the printed electrode 15.

  FIG. 14c) is due to the following method. First, after forming the printing electrode 15 with a conductive paste on the photovoltaic element 1, a coating 16 made of a low melting point metal is formed on the printing electrode 15. Further, a metal wire 10s having a coating 10h made of the same low melting point metal is heat-pressed from above.

  FIG. 14 d) shows the metal wire 10 pressed against the surface of the photovoltaic body 1 and sealed with a transparent resin 21 in that state.

  Except for the case where the temperature exceeds 400 ° C. as in the case where the passivation film is fired, any of the methods shown in FIG. 14 can be used as a device for joining the sheet-like electrode body onto the photovoltaic body 1. A known thermocompression bonding apparatus is suitable. That is, if a known vacuum laminator, roll laminator or the like is used, thermocompression bonding can be easily performed. Moreover, it is also possible to perform sealing simultaneously with the joining step by laminating the photovoltaic body 1, the sheet electrode body, and the sealing resin in order. In the case where the adhesive layer 10h and the printed electrode 15 are cured at ultraviolet rays or at room temperature, a device suitable for each may be used. Also in that case, it is preferable to press the sheet-like electrode body against the photovoltaic body and to press-bond the metal wire 10 more firmly to the photovoltaic body.

<Photovoltaic element assembly>
An assembly of photovoltaic elements obtained by connecting a plurality of photovoltaic bodies in parallel by joining a single sheet-like electrode body on the surface of the plurality of photovoltaic bodies arranged in parallel. is there. Alternatively, it is obtained by inserting a plurality of photovoltaic bodies in series by inserting a sheet-like electrode body between a plurality of parallel photovoltaic bodies and joining the sheet-like electrode body to the surface of the photovoltaic body. It is an aggregate of photovoltaic elements to be manufactured.

  FIG. 15 shows an example. FIG. 15 a) shows a sheet electrode body 11. A thick metal wire 10a and a thin metal wire 10b are sewn to the lower surface of the translucent sheet 22 with sewing threads (not shown). This sheet-like electrode body has a series part A in which a thick metal wire 10 a protrudes from the surface of the translucent sheet 22. FIG. 15 b) shows four photovoltaic elements 1 made of a polycrystalline substrate. FIG. 15c) is a view in which the lower surface of the sheet-like electrode body 11 of FIG. 15a) is joined to the surface of the photovoltaic body of FIG. 15b). In this way, if a large number of photovoltaic bodies are joined in parallel with a large sheet-like electrode body 11 in which a metal wire is sewn on the surface of a translucent sheet, a high-performance and highly reliable photovoltaic element assembly can be obtained. It can be manufactured at a very high speed, and the productivity is greatly improved.

  Furthermore, by preparing and arranging a plurality of photovoltaic element aggregates of FIG. 15c), joining the back surface of each photovoltaic element aggregate to the series part A of the adjacent photovoltaic element aggregates, FIG. 15d) shows a plurality of photovoltaic element assemblies connected in series. In this way, it is possible to efficiently produce a large-area photovoltaic element assembly.

  FIG. 15 is an example, and the photovoltaic body is not limited to a polycrystalline substrate, and can be applied to all the photovoltaic bodies described above.

<Sealing, transparent resin, photovoltaic element module>
Generally, a photovoltaic element or a photovoltaic element assembly is sealed with a transparent resin. The term “sealing” as used herein refers to forming a protective layer of a transparent resin around the photovoltaic element or the photovoltaic element assembly. By this sealing, the photovoltaic element and the photovoltaic element assembly can have mechanical strength, moisture resistance, weather resistance, electrical insulation, and design properties, and can be protected from the external environment. A photovoltaic element module is a module in which a photovoltaic element or a photovoltaic element assembly is sealed with a transparent resin and a power extraction terminal, a power extraction line, a bypass diode, and the like are attached.

  As shown in FIG. 17a), a photovoltaic module 1 and a sheet-like electrode body 11 are sandwiched and sealed with a sheet of transparent resin 21 to form a module. Conventionally, if the metal wire and the photovoltaic element 1 are simply joined and sealed together, the metal wire is likely to meander and bend, resulting in poor productivity. On the other hand, if the bonding and sealing of the sheet-like electrode body woven with metal wires and the photovoltaic body are performed together as in Patent Document 5, productivity is good, but characteristics and reliability are low. there were. However, if the sheet-like electrode body 11 of the present invention in which the photovoltaic layer 1 and the metal wire are sewn on the surface is sandwiched between the sheets of the transparent resin 21, the productivity and the characteristics and reliability are high. It is possible to form a highly functional module.

  As shown in FIG. 17 b), the sealing structure includes a surface protective layer made of glass, a fluororesin sheet or the like, or a reinforcing layer in which glass fibers and resin fibers are placed in the transparent resin 21. In addition, a substrate made of metal, ceramic, or the like may be included. Moreover, as shown in FIG. 17c), a transparent substrate such as tempered glass or an acrylic plate, and a back surface protective layer such as an aluminum film or a fluorine film may be included. Furthermore, as shown in FIG. 17d, the photovoltaic element 1 may be formed on a glass or resin substrate, and the sheet-like electrode body 11 may be provided on the back surface thereof.

  As a sealing method, there are a method of curing after coating a liquid resin, and a method of curing after pouring the liquid resin into a mold, and a method of laminating a sheet of the transparent resin 21 is preferable.

  As a method for coating a liquid resin, a spray coating method for curing, a spin coating method, and a curtain coating method are generally known. Examples of the film laminating method include a vacuum laminating method, a pressure laminating method, and a roll laminating method. The vacuum laminating method is a method in which a laminate of a photovoltaic element and a film resin is sandwiched between a substrate and a rubber sheet, and the resin is heated and melted while exhausting a gas between the substrate and the rubber sheet. The pressure laminating method is a method in which the resin is heated and melted while being pressurized with gas from above the rubber sheet, and the roll laminating method is a method in which the sheet is sandwiched between two rolls and heated and melted while being pressurized. Further, the vacuum pressure laminating method is a method in which the resin is heated and melted by evacuating the space between the substrate and the rubber sheet and applying pressure from above the rubber sheet with a gas. Any of these methods may be used in the present invention.

  Any resin can be used for the transparent resin 21 as long as it basically transmits light necessary for the photovoltaic layer. The effect is not lost depending on the type of resin. Specific resin names include ethylene vinyl acetate copolymer (EVA), ethylene methacrylic acid copolymer (EMAA), ethylene methyl acrylate copolymer (EMA), ethylene ethyl acrylate copolymer (EEA), butyral. Examples thereof include polyolefin resins such as resins, urethane resins, silicone resins, and fluororesins.

Furthermore, when the photovoltaic element is used outdoors as a solar cell, the transparency is 80% or more in the visible light wavelength region of 400 to 800 nm, and the moisture permeability at 40 ° C. and 90% RH is 0.01 to 20 g. It is desirable to have high moisture resistance at about / m ² · day. It is also known to add an inorganic compound as necessary in order to improve the weather resistance. Furthermore, in order to improve moisture resistance, it is desirable to form a cured resin in which molecules are crosslinked to form a network structure. As a curing method, there are a moisture curing type by atmospheric moisture, curing by isocyanate, and heat curing by blocking isocyanate. Among these, a method in which an inorganic polymer composed of an acrylic resin and an organosiloxane is heated and crosslinked with a blocking isocyanate is preferable. The dissociation temperature of the blocking agent is preferably 80 ° C. or higher and 220 ° C. or lower. If it is less than 80 ° C., the pot life of the resin itself is shortened. When the temperature exceeds 220 ° C., heating for dissociation may cause thermal degradation of the acrylic resin itself, which may adversely affect the photovoltaic element. Since at least a part of the blocking agent after dissociation remains in the coating film, a blocking agent that does not react with the coating composition should be selected. In order to impart adhesiveness, it is also possible to add 0.05 to 10% of a silane, titanium or aluminum coupling agent with respect to the resin content. Preferably, a silane coupling agent is added in an amount of 0.05 to 8.0%. As a specific method for forming a coating film, a resin solution is coated on a photovoltaic element by a spray coater, a spin coater, or a curtain coat, and the solvent is dried and then cured by heating.

  When the sheet-like electrode body is formed by sewing a metal wire with a transparent sewing thread, it is preferable to use the same type of transparent resin as the sewing thread. This is because the difference in refractive index between the sewing thread and the transparent resin is reduced, and the reflection of light at the interface between the two is reduced. Similarly, it is preferable to use the same kind of the translucent sheet and the transparent resin. This is also because the difference in refractive index between the translucent sheet and the transparent resin is reduced, and reflection of light at the interface between the two is reduced.

  Although the Example of the photovoltaic device of this invention and the manufacturing method of a photovoltaic device is shown below, the content of this invention is not limited by the following Examples.

<Example 1>
As shown below, the photovoltaic device shown in FIG. 1 was produced. The figure is a schematic diagram, and the length, the ratio thereof, the number of metal wires, etc. are not accurate.

[Photovoltaic body 1]
A rolled stainless steel substrate made of SUS430 having a thickness of 0.15 mm, the surface of which was washed, was prepared. Next, a thin film layer (thickness of 1 μm or less) of tungsten, silver, and zinc oxide was formed on the surface of the substrate by a known sputtering method. Next, a zinc oxide layer having a thickness of about 2 μm was formed by a known electrodeposition method. Further, by a known CVD method, two microcrystalline silicon layers each having a thickness of about 3 μm consisting of three layers of n layer, i layer and p layer, and a thickness of 1 μm or less consisting of three layers of n layer, i layer and p layer. A photovoltaic layer was formed by overlapping the amorphous silicon layer. Finally, an ITO layer having a thickness of 70 nm was formed by a known sputtering method. By cutting this substrate, a photovoltaic element 1 (239 mm × 356 mm) was produced.

The photovoltaic element 1 was subjected to the following treatment to prevent the photovoltaic layer from being short-circuited at the edge of the substrate. That is, an ITO layer etchant (FeCl ₃ ) -containing paste is screen-printed along the outer periphery of the substrate on the surface of the photovoltaic element 1, and then a portion of the ITO layer is removed by washing with pure water. . This ensured electrical separation between the upper electrode made of the ITO layer and the lower electrode made of the substrate, tungsten, silver, and zinc oxide.

[Metal wire 10]
A raw material was prepared by pasting a silver foil having a thickness of 50 μm on the outer periphery of a copper wire having a diameter of 4 to 5 mm. Next, it was shaped into a core wire having a diameter of 100 μm by a wire drawing device. This core wire was continuously produced and 500 g was wound around a bobbin. The silver coating after shaping was about 1 μm thick.

  Next, a coating made of a resin containing a conductive filler was formed around the core wire by a roll coater for enameled wire. The coating had a two-layer structure of a fully cured inner layer and an outer layer for adhesively fixing the metal wire 10 on the photovoltaic layer.

  The method for forming the inner layer is as follows. First, the core wire was unwound from the bobbin and passed through the inner layer forming treatment tank. The inner layer forming treatment tank comprises a rotating roll winding up a resin containing a filler for the inner layer and a felt. The core wire passed through the inner layer forming treatment layer first comes into contact with the rotating roll. At this time, the resin wound up by the rotary roll is applied to the core wire. Furthermore, the core wire contacts the felt. At this time, excess resin is removed. Furthermore, the core wire passes through the heating furnace. At this time, the applied resin is completely cured. In order to prevent eccentricity of the resin application amount, a series of steps of application, removal, and curing was performed a plurality of times. The outer diameter of the core wire coated with the resin was measured on the winding side of the core wire, and the value was fed back to adjust the viscosity of the resin. The feedback mechanism is a mechanism that lowers the viscosity of the resin, lowers the amount of resin wound up by the rotary roll, and decreases the coating amount. The viscosity of the resin was adjusted by adding xylene as a solvent.

  The composition of the resin used is as follows. Carbon black having a diameter of 30 ± 20 nm was used as the filler. Carbon black was adjusted to a volume density of 35%. The mixing ratio of the filler and the resin was such that the weight of the mixture was 100, and the following components were mixed and dispersed with a paint shaker to prepare a resin.

Carbon black 37.1 parts by weight Butyral resin 6.4 parts by weight Cresol resin, phenol resin, aromatic hydrocarbon resin 4.2 parts by weight Curing material 18 parts by weight diol isocyanate 18 parts by weight xylene, 12 parts diethylene glycol monomethyl ether Parts by weight, 3.6 parts by weight of cyclohexanone 0.7 parts by weight of γ-mercaptopropyltrimethoxysilane as a coupling agent

  The coating of the inner layer completed as described above had a thickness of about 5 μm and a resistivity of about 0.5 Ωcm.

  The method for forming the outer layer is as follows. The core wire coated with the inner layer was passed through the outer layer forming treatment tank. The outer layer forming treatment tank is composed of a rotating roll winding up a resin containing an outer layer filler and a die. The core wire passed through the outer layer forming treatment layer first comes into contact with the rotating roll. At this time, the resin wound up by the rotary roll is applied to the core wire. Furthermore, the core wire passes through the die. At this time, excess resin is removed. Furthermore, the core wire passes through the heating furnace. At this time, the solvent of the applied resin evaporates and the resin is semi-cured. In order to prevent eccentricity of the resin application amount, a series of steps of application, removal, and curing was performed a plurality of times. Each time the number of times was repeated, the hole diameter of the die was increased, and the thickness of the outer layer was finally 20 μm.

The composition of the resin used is as follows. Carbon black having a diameter of 30 ± 20 nm was used as the filler. The following components were mixed and dispersed with a paint shaker to prepare a resin.
Carbon black 35 parts by weight Urethane resin 41 parts by weight Phenoxy resin 14 parts by weight Hydrogenated diphenylmethane diisocyanate 6 parts by weight Solvent 4 parts by weight Aromatic solvent 4 parts by weight γ-Mercaptopropyltrimethoxysilane 0.7 parts by weight

  The resistivity of the outer layer coating completed as described above was about 0.5 Ωcm.

[Sheet-shaped electrode body 11]
The metal wire 10 was sewn on the surface of the translucent sheet 22 having a size of 239 mm × 356 mm to form a sheet-like electrode body 11. The translucent sheet used is an EVA sheet having a width of 250 mm and a thickness of 0.5 mm. The apparatus shown in FIG. 2 was used. Since the pitch of the most suitable metal wire 10 calculated from the thickness of the metal wire 10 of this example and the performance of the photovoltaic element 1 was 3 mm, the pitch of the metal wire 10 was formed to be 3 mm. did. The stitch pitch was 70 mm, and the stitch length was 2 mm. Further, at this time, the apparatus was operated at such a speed that the metal wire 10 did not stretch and break.

[Photovoltaic element]
As shown in FIG. 16, a sheet-like electrode body 11 was joined on the photovoltaic body 1. First, as shown in FIG. 16 a), a photovoltaic element 1 and a sheet-like electrode body 11 were prepared. Next, as shown in FIG. 16 b), the photovoltaic element 1 and the sheet electrode body 11 were overlapped. Next, as shown in FIG. 16c), the product made in FIG. 16b) was inserted into the vacuum laminator. This vacuum laminator includes a chamber 18, a fluororesin-based diaphragm 19, and a heating plate 20. Next, the chamber 18 was overlaid on the heating plate 20 as shown in FIG. In this state, the inside of the chamber 18 is evacuated, and the diaphragm 19 is attracted upward. Further, as shown in FIG. 16 e), the atmosphere was introduced into the chamber 18, and the sheet-like electrode body 11 was pressed against the photovoltaic body 1 by the diaphragm 19. Finally, as shown in FIG. 16f), the photovoltaic element was taken out of the vacuum laminator and cooled to complete the photovoltaic element.

  When the photovoltaic element of this example was analyzed, the junction part of the sheet-like electrode body 11 and the photovoltaic body 1 was the part shown by B in FIG.

[Comparative Example 1]
A photovoltaic device using a sheet-like electrode body in which the same metal wire as in Example 1 was woven in the same manner as in the past was produced. FIG. 18 shows the photovoltaic element of this example. FIG. 18a) is a plan view of the photovoltaic element of this comparative example. The photovoltaic element of this example is formed by joining a sheet-like electrode body 11 in which a metal wire 10 and transparent yarn are woven in a plain weave to the surface of the photovoltaic body 1. FIG. 18b) is an enlarged view of the sheet-like electrode body 11 in the portion surrounded by the square B in FIG. 18a), the left figure is a top view, and the right figure is a bottom view. Further, FIG. 18c) is a cross-sectional view of the photovoltaic element taken along the lines AA 'and CC' shown in the top view.

  The photovoltaic element of this example was produced in exactly the same manner as in Example 1 except for the step of producing a sheet-like electrode body. First, the same metal wire as in Example 1 was produced. In addition, a highly transparent polyester yarn having a diameter of 0.1 mm was prepared as a transparent fiber. As the vertical fibers, the metal wire 10 and the polyester yarn were woven in a ratio of 5: 1. All the transverse fibers were polyester yarns. Next, the sheet-like electrode body 11 was woven by plain weaving using a known loom. Since the pitch of the vertical fibers and the horizontal fibers at this time was 0.5 mm, it was a sheet-like electrode body having a sufficient shape retention force. Thereafter, using the same vacuum laminator as in Example 1, the sheet-like electrode body 11 was joined on the photovoltaic body.

  When the photovoltaic element of this example was analyzed, the joint surface between the sheet-like electrode body 11 and the photovoltaic body 1 was a portion indicated by D in FIGS. The area was close to point contact as shown in white in FIG. B), and was much smaller than the joint surface of Example 1.

[Comparative Example 2]
As another comparative example, a modified sheet-like electrode body of Comparative Example 1 was produced. As in Comparative Example 1, the sheet-like electrode body of this example is a plain weave of metal wires and polyester yarns, but all the longitudinal fibers are metal wires and the pitch is 3 mm. Furthermore, the pitch of the transverse fibers (polyester yarn) was also 3 mm. Other than that was carried out in the same manner as in Comparative Example 1.

  This pitch of 3 mm is rough as a pitch for weaving the same metal wire as in Example 1 and the same polyester yarn as in Comparative Example 1. Therefore, sufficient tension was not applied to the metal wire, and the shape of the sheet-like electrode body of this example was extremely unstable. For this reason, it was deformed during the process of being stacked on the photovoltaic element, and the distance between the fibers was shifted.

[Characteristic]
When the characteristics of the photovoltaic elements fabricated in Comparative Examples 1 and 2 were measured, it was found that the series resistance component was large and the conversion efficiency tended to be low. Moreover, when the photovoltaic element of the comparative example 1 was hold | maintained in a high temperature high humidity state, the tendency for a serial resistance component to become large was also shown. The photovoltaic element produced in Example 1 had a smaller series resistance component and higher conversion efficiency than Comparative Examples 1 and 2. In addition, no increase in the series resistance component was observed even when kept in a high temperature and high humidity state.

  Further, the productivity of the sheet-like electrode body of Example 1 in which the metal wire is sewn on the translucent sheet is comparable to the productivity of Comparative Examples 1 and 2 in which the metal wire and the transparent fiber are plain weave. It was a thing. From the above, the effects of the present invention are clear.

<Example 2>
The photovoltaic element of this example is shown in FIG. FIG. 4 shows each part of the photovoltaic device of this example in the same format as FIG. The sheet-like electrode body 11 of this example is obtained by sewing a metal wire 10 similar to that of Example 1 on a translucent sheet 22 similar to that of Example 1 with a sewing thread 14. The pitch of the metal wires 10 was 3 mm, the same as in Example 1. As the sewing thread 14, a highly transparent polyester thread having a diameter of 0.1 mm was used.

  The metal wire 10 was sewn on the lower surface of the translucent sheet 22 by a main sewing using a known main sewing machine having the mechanism of FIG. 5 using a polyester yarn as a needle yarn and a metal wire as a bobbin yarn. At this time, the pitch of the seam was set to 70 mm as in the first embodiment. Since a sewing machine having three needles was used and the number of rotations was sewn at 1000 rpm, the metal wire 10 and the translucent sheet 22 could be sewn much faster than in the case of Example 1. It was possible.

  When the photovoltaic element of this example was analyzed, the joint surface between the sheet-like electrode body 11 and the photovoltaic body 1 was a portion indicated by B in FIG. This was larger than the joint surface of Example 1.

  When the characteristics of the produced photovoltaic device were measured in the same manner as in Example 1, the conversion efficiency of the photovoltaic device of this example was higher than that of Example 1. In addition, no increase in the series resistance component was observed even when kept in a high temperature and high humidity state.

  As a result of analysis, the photovoltaic element of this example had a smaller series resistance component than that of Example 1. From this, the effect of sewing the metal wire on the translucent sheet with the sewing thread is clear.

<Example 3>
The photovoltaic element of this example was manufactured in the same manner as in Example 2 except that only the sheet-like electrode body was different from that in Example 2. In the same manner as in Example 2, the sheet-like electrode body of this example is sewn on the same light-transmitting sheet as in Example 1 by using the same metal wire as in Example 1 with the same sewing thread as in Example 2. It is a thing. However, as shown in FIG. 6, the sewing thread 14 is sewn from the top of the metal wire 10 placed as a decorative thread on the lower surface of the translucent sheet 22 in the direction perpendicular to the metal wire 10 by the main sewing. This is different from the second embodiment.

  The sheet-like electrode body of this example was produced using the apparatus of FIG. First, the bobbin around which the metal wire 10 was wound was set on the bobbin setting part in the left part of the apparatus. Next, the metal wire 10 was pulled out in the horizontal right direction from the bobbin in a state of being arranged in parallel at a pitch of 3 mm. In FIG. 9A, the metal wire 10 appears to be one, but the metal wires are arranged in the depth direction of the drawing. Separately, the translucent sheet 22 was pulled rightward from the roll of the translucent sheet 22 in the same manner as the metal wire 10. The plurality of metal wires 10 drawn out side by side were placed on the drawn translucent sheet 22 and then inserted into a transport roll. Further, a sewing thread (not shown) is sewed onto the translucent sheet 22 from above the metal wire 10 by the sewing device on the right side of the transport roll, and the metal wire 10 and the translucent sheet 22 are sewn. It was. The main sewing apparatus has a mechanism including the sewing machine needle 23 and the shuttle 24 shown in FIG. For sewing the sewing thread, the same polyester as in Example 2 was used for both the needle thread and the bobbin thread. The stitch pitch was 3 mm, and the rotational speed of the sewing machine was 1000 rpm. While the sewing thread was sewn, the conveyance roll was stopped, and the sewing direction of the sewing thread was a direction perpendicular to the metal wire 10 (the depth direction in the drawing). The integrated metal wire 10 and the translucent sheet 22 were divided by a division press to obtain a sheet-like electrode body 11. The place where the sewing thread is sewn is the place shown in FIG. 6a). In FIG. 6 a), the sewing interval of the sewing thread 14 was set to 70 mm, which is the same as the stitch interval of Example 2. Since the sheet-like electrode body was produced as described above, it was possible to form the sheet-like electrode body at a higher speed than in Example 2.

  When the characteristics of the photovoltaic element of this example were measured, conversion efficiency equivalent to that of Example 2 was obtained. In addition, no significant increase in the series resistance component was observed even when kept in a high temperature and high humidity state.

  From the above, the effect of sewing the sewing thread in the direction intersecting with the metal line using the metal line as a decorative thread is clear.

<Example 4>
This example differs from Example 3 only in the method of sewing the sewing thread of the sheet-like electrode body. The photovoltaic element of this example is shown in FIG. The sewing thread 14 is sewn on the translucent sheet 22 in this example by single ring sewing. All other operations were performed in the same manner as in Example 3.

  The apparatus for forming the sheet-like electrode body used in this example was the apparatus shown in FIG. However, a device having a sewing device different from the device of Example 3 was used. The main sewing apparatus has a mechanism composed of the sewing needle 23 and the looper shown in FIG. 11, and can perform single ring sewing by looping. As the sewing thread, the same polyester as in Example 3 was used. The stitch pitch was the same as in Example 3, 3 mm, and the rotational speed of the sewing machine was similarly 1000 rpm. Further, as in Example 3, while the sewing thread was sewn, the conveyance roll was stopped, and the sewing direction of the sewing thread was a direction perpendicular to the metal wire 10 (the depth direction in the drawing). The integrated metal wire 10 and the translucent sheet 22 were divided by a division press to obtain a sheet-like electrode body 11. The location where the sewing thread is sewn is the location shown in FIG. In FIG. 10 a), the sewing interval of the sewing thread 14 was set to 70 mm as in the third embodiment. Since the sewing device of this example was a device for single ring sewing, the bobbin thread replacement work required in the case of Example 3 was unnecessary. Therefore, it was possible to form the sheet-like electrode body at a higher speed than in the case of Example 3.

  When the characteristics of the photovoltaic element of this example were measured in the same manner as in Example 3, conversion efficiency equivalent to that in Example 3 was obtained. In addition, no increase in the series resistance component was observed even when kept in a high temperature and high humidity state.

  From the above, the effect of sewing by looping is clear.

<Example 5>
This example differs from Example 4 only in the way of sewing the sewing thread of the sheet-like electrode body. The sewing thread 14 is sewn on the translucent sheet 22 in this example by single-ring sewing with a plurality of needles as shown in FIG. All other operations were performed in the same manner as in Example 4.

  The apparatus for forming the sheet-like electrode body used in this example was the apparatus shown in FIG. However, a device having a sewing device different from the device of Example 4 was used. The sewing device of this example basically has a mechanism comprising the sewing needle 23 and looper shown in FIG. 11, and is a device that can perform single ring sewing by looping. However, it differs from that of Example 4 in that it has the same number of sewing needles as the number of metal wires 10 set in the apparatus of FIG.

  In the sewing apparatus of this example, the sewing needles are arranged in a line at equal intervals, and each sewing needle performs the single ring sewing shown in the enlarged view of FIG. FIG. 13 is a perspective view. In the figure, only the needle thread 25 (sewing thread) is shown, and the needle, looper, and translucent sheet are not shown. Each sewing needle does not move in the direction of arrow D, and the translucent sheet moves in the direction opposite to arrow D, so that sewing of the sewing thread proceeds relatively in the direction of arrow D. The metal wire is arranged so as to come to the position and direction indicated by the broken line in FIG. 13a), and one metal wire is sewn to the translucent sheet by one sewing thread. The unwinding direction of the metal wire 10 and the unwinding direction of the translucent sheet 22 shown in FIG. 9 correspond to the direction of the arrow D in FIG. In FIG. 13a), each time two stitches are sewn, the sewing position is changed to the direction of arrow D by moving the needle position by a distance d in the direction perpendicular to the direction indicated by arrow D, as in the portion indicated by t. On the other hand, it is changed diagonally. However, in this example, this movement of the needle position is performed once every 17 stitches. Since the stitch pitch in this example is 3 mm, which is the same as that in Example 4, as shown by t in FIG. 13a), the portion where the sewing direction changes obliquely with respect to the direction of the arrow D It appeared once every 71 mm in the direction. Further, FIG. 13b) is a diagram when the sewing method shown in FIG. 13a) is simultaneously performed by ten sewing needles arranged in a line at equal intervals d. In this example, the same number of sewing machines as metal wires are used. This is different from FIG. The distance d between the sewing needles and the pitch of the metal wires were 3 mm.

  Moreover, the polyester similar to Example 4 was used for the sewing thread. The number of rotations of the sewing machine was also 1000 rpm, the same as in Example 4. The integrated metal wire 10 and the translucent sheet 22 were divided by a division press to obtain a sheet-like electrode body 11. Unlike the case of Example 4, the sheet-like electrode body forming apparatus of this example was able to sew the sewing thread without stopping the transport roll. Therefore, it was possible to form the sheet-like electrode body at a higher speed than in the case of Example 4.

  When the characteristics of the photovoltaic element of this example were measured in the same manner as in Example 4, conversion efficiency equivalent to that in Example 4 was obtained. In addition, no increase in the series resistance component was observed even when kept in a high temperature and high humidity state.

  From the above, the effect of sewing a metal wire by ring stitching with a plurality of needles is clear.

<Example 6>
The photovoltaic element of this example differs from Example 5 only in that a non-woven fabric made of glass fiber having a weight per unit area of 80 g / m ² is used as the translucent sheet. By using this non-woven fabric, the resistance when the sewing needle is passed through the translucent sheet can be reduced, and the number of rotations of the sewing device can be increased from 1000 rpm to 1500 rpm. It was possible to form a sheet-like electrode body at high speed.

  The photovoltaic element of this example was sealed with a known laminator and sealing resin (EVA), and the characteristics were measured in the same manner as in Example 5. As a result, the same conversion as in Example 5 was obtained. Efficiency was obtained. In addition, no increase in the series resistance component was observed even when kept in a high temperature and high humidity state.

  As mentioned above, the effect of using a transparent fiber nonwoven fabric for a translucent sheet is clear.

<Example 7>
The photovoltaic element assembly of this example was produced as follows. The photovoltaic element assembly of this example is shown in FIG.

  First, phosphorus was thermally diffused on the surface of a 6-inch p-type polycrystalline substrate to form an n-layer, thereby producing a pn junction. Next, an antireflection film made of silicon nitride was formed on the n layer using a vacuum film forming apparatus, and an excess n layer on the side surface and back surface of the substrate was removed with an etching solution. Furthermore, a silver paste and an aluminum paste were printed in a predetermined shape on the back surface and fired using a known firing furnace to form a back electrode. Thus, the photovoltaic element 1 was completed. Four completed photovoltaic elements were arranged in a horizontal row as shown in FIG. 15b).

  On the other hand, a silver paste containing silver particles, glass frit, organic vehicle, solvent, etc. is applied to a copper wire having a diameter of 0.1 mm by a roll coater, and the applied silver paste is baked in a temporary baking furnace (about 200 ° C.) to make it thin. A metal wire 10b was produced. At this time, the thickness of the applied paste layer was 20 μm. Further, the same silver paste was temporarily baked on a copper wire having a diameter of 0.15 mm to produce a thick metal wire 10a. The produced thick metal wire 10a and the thin metal wire 10b were sewn on the translucent sheet 22 in this order as shown in FIG. At this time, a portion indicated by A in FIG. 15a) is a portion in which the thick metal wire 10a protrudes from the translucent sheet. The pitch of the thin metal wires was 3 mm, and the pitch of the thick metal wires was 20 mm. A glass nonwoven fabric was used as the translucent sheet.

  Next, the sheet-like electrode body 11 of FIG. 15a) is overlaid on the photovoltaic body of FIG. 15b) so that the lower surface of the sheet-like electrode body 11 and the light incident surface of the photovoltaic body 1 are aligned. 15c) was formed. Further, a plurality of laminates shown in FIG. 15c) are prepared, and the prepared laminates are sequentially arranged so that adjacent laminates are placed on the region A shown in FIG. 15a). A laminate was obtained. However, only the sheet-like electrode bodies of the laminated body arranged last have no area A and have a size that fits on the photovoltaic body.

  Finally, in a state where both sides of the large laminate of FIG. 15d) are sandwiched between quartz plates and put under pressure, it is put into a firing furnace at 500 ° C., and the silver paste layer formed on the surface of the metal wire 10 is completely sintered. I let you. At this time, the silver paste penetrated the silicon nitride film formed on the substrate surface, and an electrical contact between the metal line and the n layer was formed. At the same time, the parallel photovoltaic bodies 1 shown in FIG. 15 a) are electrically connected in parallel by the sheet-like electrode body 11, and the plurality of parallel laminated bodies shown in FIG. (Shown in FIG. 15c) was electrically connected in series by a sheet-like electrode body.

  As described above, since a plurality of substrates (photovoltaic bodies) can be connected in series and in parallel by the produced sheet-like electrode body, a large-area photovoltaic element assembly can be manufactured very easily. It was possible.

[Comparative Example 3]
A photovoltaic element assembly was produced using the sheet-like electrode body obtained by plain weaving the metal wires of Example 7. It was produced in the same manner as in Example 7 except that a plain woven fabric was used as the sheet-like electrode body. The interval between the transverse fibers and the interval between the longitudinal fibers of the used fabric was 3 mm.

[Characteristic]
When the characteristics of the photovoltaic device produced in Comparative Example 3 were measured, it was found that the series resistance component was large and the conversion efficiency tended to be low. Moreover, when the photovoltaic element of the comparative example 3 was hold | maintained in a high temperature high humidity state, the tendency for a serial resistance component to become large was also shown. The photovoltaic element assembly produced in Example 7 had a smaller series resistance component and higher conversion efficiency than Comparative Example 3. In addition, no significant increase in the series resistance component was observed even when kept in a high temperature and high humidity state.

  From the above, the effects of the present invention are clear. That is, according to the present invention, a photovoltaic device assembly having high performance, high reliability, and extremely high productivity was obtained.

<Example 8>
The photovoltaic element module of this example was manufactured as follows. The photovoltaic element of Example 2 was sandwiched between two PMMA plates and heat-sealed with a vacuum laminator. The PMMA plate used had a thickness of 2 mm. Simultaneously with the joining of the sheet-like electrode body and the photovoltaic body, the resin sealing process was completed and it was possible to manufacture very easily.

<Example 9>
The photovoltaic element module of this example is different from Example 8 only in the photovoltaic element. The photovoltaic element of this example was produced as follows. A sheet-like electrode body was produced using PMMA yarn instead of the polyester yarn of Example 2, and laminated on the photovoltaic body produced in the same manner as in Example 2.

  When the short-circuit current of the photovoltaic element module of this example and the photovoltaic element module of Example 8 were compared, the short-circuit current of the photovoltaic element module of this example was short-circuited by the photovoltaic element module of Example 8. It was larger than the current value. This is considered to be because there is no reflection of light at the interface between the sewing thread (PMMA thread) and the sealing resin (PMMA) in this example.

It is the schematic which shows the photovoltaic element of Example 1 of an embodiment. It is the schematic which shows an example of the manufacturing method of the photovoltaic element of FIG. It is a figure explaining the modification of the photovoltaic element of FIG. It is the schematic which shows the photovoltaic element of Example 2 of an embodiment. It is the schematic which shows an example of the manufacturing method of the photovoltaic element of FIG. It is the schematic which shows the photovoltaic element of Example 3 of an embodiment. It is a figure explaining the modification of the photovoltaic device of FIG. It is a figure explaining the modification of the photovoltaic device of FIG. It is the schematic which shows an example of the manufacturing method of the photovoltaic element of FIG. It is the schematic which shows the photovoltaic element of Example 4 of an embodiment. It is the schematic which shows an example of the manufacturing method of the photovoltaic element of FIG. It is a figure which shows the basic component which comprises a seam. It is a figure explaining the method of performing single ring stitching simultaneously with a plurality of needles. It is a figure explaining an example of the joining method of a sheet-like electrode body and a photovoltaic body. It is the schematic which shows an example of the photovoltaic element assembly | assembly of this invention. FIG. 3 is a schematic view showing a method for producing the photovoltaic element of Example 1. It is the schematic which shows an example of the photovoltaic element module of this invention. 3 is a schematic view showing a photovoltaic element of Comparative Example 1. FIG. It is a figure explaining a prior art. It is a figure explaining a prior art. It is a figure explaining a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photovoltaic body 10 Metal wire 11 Sheet-like electrode body 12 Fiber 14 Sewing thread 15 Printed electrode 16 Cover (solder)
18 Chamber 19 Diaphragm 20 Heating plate 21 Transparent resin 22 Translucent sheet 23 Sewing needle 24 Hook 25 Needle thread (upper thread, sewing thread)
26 Bobbin thread (lower thread)
27 Fabric

Claims (16)

  A photovoltaic element comprising: a sheet-like electrode body having a metal wire sewn on a surface of a translucent sheet; and a photovoltaic body.   The photovoltaic element according to claim 1, wherein the metal wire is sewn with a sewing thread.   The photovoltaic element according to claim 2, wherein the sewing thread is transparent.   The photovoltaic element according to claim 2 or 3, wherein the metal wire is sewn as a decorative thread.   The photovoltaic element according to any one of claims 2 to 4, wherein the sewing thread is sewn in a direction intersecting with the metal line.   The photovoltaic element according to claim 2, wherein the sewing is performed by looping.   The photovoltaic element according to any one of claims 2 to 6, wherein the sewing is performed by chain stitching with a plurality of needles.   The photovoltaic element according to any one of claims 1 to 7, wherein the sheet-like electrode body has two or more kinds of metal wires.   The photovoltaic element according to any one of claims 1 to 8, wherein the translucent sheet is a transparent fiber nonwoven fabric.   A photovoltaic element assembly comprising a plurality of photovoltaic elements connected in parallel by a sheet-like electrode body in which a metal wire is sewn on a surface of a translucent sheet.   A photovoltaic element assembly comprising a plurality of photovoltaic elements or photovoltaic element aggregates connected in series by a sheet-like electrode body in which metal wires are sewn on the surface of the translucent sheet body.   A photovoltaic device module in which the photovoltaic device according to any one of claims 1 to 9 or the photovoltaic device assembly according to claim 10 or 11 is sealed with at least a transparent resin.   13. The photovoltaic element module according to claim 12, wherein the transparent resin is the same kind of resin as the sewing thread.   A method for manufacturing a photovoltaic device, comprising a step of joining a sheet-like electrode body in which a metal wire is sewn on a surface of a translucent sheet and a photovoltaic body.   The sheet-like electrode body is formed by sewing a transparent thread on the translucent sheet after placing the metal wire on the surface of the translucent sheet. Photovoltaic element manufacturing method.   The step of joining the sheet-like electrode body sewn on the surface of the translucent sheet and the photovoltaic body and the step of sealing the photovoltaic body with a transparent resin are performed in the same step. A method for producing a photovoltaic element module, comprising:

Images