JP2007165785A - Solar cell with interconnector, solar cell string, and solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell with an interconnector that can decrease the warp of a solar cell, a solar cell string, and a solar cell module. <P>SOLUTION: The solar cell with the interconnector, the solar cell string, and the solar cell module that include a solar cell provided with a bus bar electrode configured by a plurality of first connection sections that are connected to the interconnector and a plurality of first non-connection sections that are not connected to the interconnector alternately arranged and a finger electrode that is extended from the bus bar electrode on the first principal plane of a semiconductor substrate, the interconnector has a plurality of small cross-section areas where the cross-section area of a cross-section vertical in the longitudinal direction of the interconnector is locally small and a plurality of non small cross-section area sections positioned between a plurality of the small cross-section area sections, the small cross-section area sections are each disposed at positions corresponding to the first non-connection sections, and the first non-connection sections corresponding to the non small cross-section area sections are disposed between the first non-connection sections at positions corresponding to the small cross-section area sections, are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solar cell with an interconnector, a solar cell string, and a solar cell module.

  In recent years, a solar cell that directly converts solar energy into electric energy has been rapidly expected as a next-generation energy source particularly from the viewpoint of global environmental problems. There are various types of solar cells, such as those using compound semiconductors or organic materials, but the mainstream is currently using silicon crystals.

  FIG. 8 shows a schematic cross-sectional view of an example of a conventional solar cell. Here, in the solar cell, an n + layer 11 is formed on the light receiving surface of a p-type silicon substrate 10 as a semiconductor substrate, whereby a pn junction is formed by the p-type silicon substrate 10 and the n + layer 11. An antireflection film 12 and a silver electrode 13 are formed on the light receiving surface of the p-type silicon substrate 10, respectively. A p + layer 15 is formed on the back surface of the p-type silicon substrate 10 opposite to the light receiving surface. An aluminum electrode 14 and a silver electrode 16 are formed on the back surface of the p-type silicon substrate 10, respectively.

  9A to 9I show an example of a conventional solar cell manufacturing method. First, as shown in the schematic perspective view of FIG. 9A, a silicon ingot 17 obtained by recrystallizing the raw material of p-type silicon crystal in a crucible and cutting it into silicon blocks 18 is cut. Next, as shown in the schematic perspective view of FIG. 9B, the silicon block 18 is cut with a wire saw, whereby the p-type silicon substrate 10 is obtained.

  Next, the damage layer 19 at the time of slicing the p-type silicon substrate 10 shown in the schematic cross-sectional view of FIG. 9C is removed by etching the surface of the p-type silicon substrate 10 with alkali or acid. At this time, if the etching conditions are adjusted, minute irregularities (not shown) can be formed on the surface of the p-type silicon substrate 10. Due to the unevenness, reflection of sunlight incident on the surface of the p-type silicon substrate 10 is reduced, and the conversion efficiency of the solar cell can be increased.

Subsequently, as shown in the schematic cross-sectional view of FIG. 9D, a dopant liquid containing a compound containing phosphorus on one main surface (hereinafter referred to as “first main surface”) of the p-type silicon substrate 10. 20 is applied. Then, the p-type silicon substrate 10 after the application of the dopant liquid 20 is heat-treated at a temperature of 800 ° C. to 950 ° C. for 5 to 30 minutes, whereby phosphorus as an n-type dopant diffuses into the first main surface of the p-type silicon substrate 10. Then, as shown in the schematic sectional view of FIG. 9E, the n + layer 11 is formed on the first main surface of the p-type silicon substrate 10. As a method for forming the n + layer 11, there is a method by vapor phase diffusion using P ₂ O ₅ or POCl ₃ besides the method of applying the dopant liquid.

  Next, after removing the glass layer formed on the first main surface of the p-type silicon substrate 10 during the diffusion of phosphorus by acid treatment, as shown in the schematic cross-sectional view of FIG. An antireflection film 12 is formed on the first main surface. Known methods for forming the antireflection film 12 include a method of forming a titanium oxide film using an atmospheric pressure CVD method and a method of forming a silicon nitride film using a plasma CVD method. In addition, when phosphorus is diffused by a method of applying a dopant solution, the n + layer 11 and the antireflection coating 12 are simultaneously formed by using a dopant solution that contains the material of the antireflection coating 12 in addition to phosphorus. It can also be formed. The antireflection film 12 may be formed after the silver electrode is formed.

  9 (g), an aluminum electrode 14 is formed on the other main surface (hereinafter referred to as “second main surface”) of the p-type silicon substrate 10 and p-type silicon. A p + layer 15 is formed on the second main surface of the substrate 10. The aluminum electrode 14 and the p + layer 15 are formed by, for example, printing aluminum paste made of aluminum powder, glass frit, resin and organic solvent by screen printing or the like, and then heat-treating the p-type silicon substrate 10 to melt the aluminum. A p + layer 15 is formed under the aluminum-silicon alloy layer formed by alloying with silicon, and an aluminum electrode 14 is formed on the second main surface of the p-type silicon substrate 10. Further, the difference in dopant concentration between the p-type silicon substrate 10 and the p + layer 15 causes a potential difference (acts as a potential barrier) at the interface between the p-type silicon substrate 10 and the p + layer 15, and the photogenerated carriers are converted into p-type silicon The recombination in the vicinity of the second main surface of the substrate 10 is prevented. This improves both the short circuit current (Isc) and the open circuit voltage (Voc) of the solar cell.

  Thereafter, a silver electrode 16 is formed on the second main surface of the p-type silicon substrate 10 as shown in the schematic cross-sectional view of FIG. The silver electrode 16 can be obtained, for example, by heat-treating the p-type silicon substrate 10 after printing a silver paste made of silver powder, glass frit, resin and organic solvent by screen printing or the like.

  Then, a silver electrode 13 is formed on the first main surface of the p-type silicon substrate 10 as shown in the schematic cross-sectional view of FIG. The silver electrode 13 is a line of the silver electrode 13 in order to keep the series resistance including the contact resistance with the p-type silicon substrate 10 low and to reduce the formation area of the silver electrode 13 so as not to reduce the amount of incident sunlight. Pattern design such as width, pitch and thickness is important. As a method for forming the silver electrode 13, for example, a silver paste made of silver powder, glass frit, resin and organic solvent is printed on the surface of the antireflection film 12 by screen printing or the like, and then the p-type silicon substrate 10 is heat-treated. As a result, a fire-through method in which silver paste penetrates the antireflection film 12 and allows good electrical contact with the first main surface of the p-type silicon substrate 10 is used in the mass production line.

  As described above, the solar cell having the configuration shown in FIG. 8 can be manufactured. The surface of the silver electrode 13 and the silver electrode 16 can be coated with solder by immersing the p-type silicon substrate 10 after the formation of the silver electrode 13 and the silver electrode 16 in a molten solder bath. This solder coating may be omitted depending on the process. Further, the solar cell manufactured as described above can be irradiated with simulated sunlight using a solar simulator, and the current-voltage (IV) characteristic of the solar cell can be measured to inspect the IV characteristic.

  In many cases, a plurality of solar cells are connected in series to form a solar cell string, and then the solar cell string is sealed with a sealing material and sold and used as a solar cell module.

  10A to 10E show an example of a conventional method for manufacturing a solar cell module. First, as shown in the schematic perspective view of FIG. 10A, an interconnector 31 that is a conductive member is connected to the silver electrode on the first main surface of the solar cell manufactured as described above. A solar cell 30 with an interconnector is produced.

  Next, as shown in the schematic perspective view of FIG. 10B, the solar cells 30 with interconnectors are arranged in a row and connected to the silver electrodes on the first main surface of the solar cells 30 with interconnectors. The other end of the connector 31 is connected to the silver electrode on the second main surface of the other solar cell 30 with an interconnector to produce a solar cell string 34.

  Next, as shown in the schematic perspective view of FIG. 10C, the solar cell strings 34 are arranged side by side, and the interconnector 31 protruding from both ends of the solar cell string 34 and the other solar cell strings 34 are protruded from both ends. The solar cell strings are connected to each other by connecting the interconnector 31 being connected in series using the wiring member 33 that is a conductive member.

  Subsequently, as shown in the schematic perspective view of FIG. 10D, the connected solar cell string 34 is sandwiched between EVA (ethylene vinyl acetate) films 36 as a sealing material, and then the glass plate 35 and the back film. 37. Then, when the bubbles that have entered between the EVA films 36 are decompressed and heated, the EVA film 36 is cured and the solar cell string 34 is sealed in the EVA. Thereby, a solar cell module is produced.

Thereafter, as shown in the schematic side view of FIG. 10E, the solar cell module is disposed in the aluminum frame 40, and the terminal box 38 including the cable 39 is attached to the solar cell module. The solar cell module manufactured as described above is irradiated with simulated sunlight using a solar simulator, and the current-voltage (IV) characteristics of the solar cell are measured to inspect the IV characteristics.
JP 2005-142282 A

As solar power generation systems rapidly spread, it is essential to reduce the manufacturing cost of solar cells. In reducing the manufacturing cost of solar cells, increasing the size and reducing the thickness of a silicon substrate, which is a semiconductor substrate, is a very effective means. However, with the increase in size and thickness of silicon substrates, when forming solar cells with interconnectors and solar cell strings, solar cell electrodes (such as bus bar electrodes) and copper interconnectors are fixed with solder or the like. in the cooling step after the heating step of connecting, the thermal expansion coefficient difference between the silicon substrate and the interconnector of a solar cell (relative to thermal expansion coefficient of 3.5 × 10 ^-6 / K in silicon, copper 17.6 × 10 ^{- 6} / K, which is a difference of about 5 times), a large internal stress is generated in each of the silicon substrate and the interconnector, causing a problem that the solar cell is largely warped.

  This is because, after the solar cell electrode and the interconnector are fixed in the heating step, when the solar cell electrode and the interconnector in a heated state are cooled to room temperature, the interconnector contracts more than the solar cell. It is considered that the concave warpage occurred in the solar cell. The warp generated in the solar cell causes a transport error and a crack in the solar cell in the transport system of the automated solar cell module production line. Moreover, when the solar cell which comprises a solar cell string has curvature, in the formation process of a solar cell string, the sealing process by the sealing material for preparation of a solar cell module, etc. locally to a solar cell A strong force is applied, causing cracks in the solar cell.

  For example, Patent Document 1 discloses a method of providing a small cross-sectional area portion having a locally reduced cross-sectional area in an interconnector that connects adjacent solar cells. As described above, when the interconnector and solar cell that have been heated by the heating step are cooled to room temperature, a concave warp occurs in the solar cell. At that time, a force (restoring force) for returning to the original shape is generated in the solar cell, and this restoring force applies tensile stress to the interconnector. According to the method disclosed in Patent Literature 1, when a tensile stress is applied to the interconnector, a small cross-sectional area that is relatively weak compared to other portions is stretched to reduce the warpage of the solar cell. be able to.

  FIG. 13 shows a schematic cross-sectional view of an example of a solar cell string in which solar cells having the light receiving surface shown in FIG. 11 and the back surface shown in FIG. 12 are connected using the interconnector described in Patent Document 1. A schematic plan view of the light receiving surface of the solar cell string shown in FIG. 14 is shown in FIG.

  Here, as shown in FIG. 11, the silver electrode 13 on the light receiving surface of the solar cell is composed of a single linear bus bar electrode 13a having a relatively large width and a plurality of relatively small lines extending from the bus bar electrode 13a. The finger electrode 13b has a shape. The bus bar electrode 13a includes a linear first connection part 51 for fixing and connecting to the interconnector, and a first non-connection part 42 that is a gap that is not connected to the interconnector. The portions 51 and the first non-connecting portions 42 are alternately arranged. Specifically, three first connection portions 51 are formed in one bus bar electrode 13a shown in FIG. 11, and between the adjacent first connection portions 51 and on the first main surface of the p-type silicon substrate 10. A first non-connecting portion 42 is formed at each end.

  Further, as shown in FIG. 12, the aluminum electrode 14 is formed on almost the entire second main surface of the p-type silicon substrate 10, and the silver electrode 16 is only a part of the second main surface of the p-type silicon substrate 10. Is formed. Here, the silver electrode 16 corresponds to a second connecting portion for connecting to the interconnector, and the aluminum electrode 14 positioned between the silver electrodes 16 arranged in the longitudinal direction of the silver electrode 16 is not connected to the interconnector. It corresponds to a second non-connection part. Therefore, the silver electrodes 16 as the second connection portions and the aluminum electrodes 14 as the second non-connection portions are alternately arranged. In addition, the 2nd main surface of the p-type silicon substrate 10 as a semiconductor substrate turns into a main surface on the opposite side to the 1st main surface of the p-type silicon substrate 10 as a semiconductor substrate.

  Further, as shown in FIG. 13, in the solar cell string using the interconnector described in Patent Document 1, the interconnector 31 is fixedly connected to the first connection part 51 of the light receiving surface of the solar cell with solder or the like. However, it is fixed and connected to the silver electrode 16 on the back surface of another adjacent solar cell with solder or the like. In FIG. 13, the description of the n + layer and the p + layer is omitted.

  As shown in FIGS. 13 and 14, the small cross-sectional area portion 41 of the interconnector 31 has a position corresponding to the first non-connecting portion 42 on the light receiving surface of the solar cell and a second non-connecting portion on the back surface of the solar cell. The small cross-sectional area 41 of the interconnector 31 is not fixed by solder or the like. Accordingly, when a tensile stress is applied to the interconnector 31, the small cross-sectional area 41 having a relatively low strength as compared with other portions can be freely extended, so that the warpage of the solar cell can be reduced. it can. However, further improvements are desired with respect to reducing solar cell warpage.

  Then, the objective of this invention is providing the solar cell with an interconnector and solar cell string which can further improve reduction of the curvature of a solar cell, and the solar cell module containing the solar cell string.

  The present invention includes a bus bar electrode in which a plurality of first connection portions for connecting to an interconnector and a plurality of first non-connection portions not connected to the interconnector are alternately arranged, a finger electrode extending from the bus bar electrode, Is a solar cell with an interconnector, wherein the interconnector is connected to the first connection portion of the solar cell, the interconnector being perpendicular to the longitudinal direction thereof. A plurality of small cross-sectional area portions where the cross-sectional area of the cross-section is locally reduced, and a non-small cross-sectional area portion located between the small cross-sectional area portions, At least one first non-connecting portion corresponding to the non-small cross-sectional area portion is arranged between the first non-connecting portions arranged at positions corresponding to the one non-connecting portion and located at positions corresponding to the small cross-sectional area portions. Interconnector Characterized in that it is a solar battery can.

  Here, in the solar cell with an interconnector according to the present invention, the second connection portion for connecting to the interconnector is not connected to the interconnector on the second main surface opposite to the first main surface of the semiconductor substrate. The second non-connecting portions can be alternately arranged.

  Moreover, in the solar cell with an interconnector of this invention, it is preferable to arrange | position a 1st connection part and a 2nd connection part in the mutually symmetrical position regarding a semiconductor substrate, respectively.

  Moreover, in the solar cell with an interconnector of the present invention, the bus bar electrode has three first non-connection portions, and the small cross-sectional area portions are arranged at positions corresponding to the first non-connection portions located at both ends. be able to.

  The present invention also provides a bus bar electrode in which a plurality of first connection portions for connecting to an interconnector and a plurality of first non-connection portions not connected to the interconnector are alternately arranged, and a finger electrode extending from the bus bar electrode And a solar cell string in which a plurality of solar cells provided on the first main surface of the semiconductor substrate are connected by an interconnector, and the interconnector has a cross-sectional area of a cross section perpendicular to the longitudinal direction locally. A plurality of small cross-sectional area portions that are small, and a non-small cross-sectional area portion located between the small cross-sectional area portions, each of the small cross-sectional area portions corresponding to the first non-connecting portion And at least one first non-connection portion corresponding to the non-small cross-sectional area portion is disposed between the first non-connection portions located at positions corresponding to the small cross-sectional area portions. With features That.

  Here, in the solar cell string of the present invention, on the second main surface opposite to the first main surface of the semiconductor substrate, the second connection portion for connecting to the interconnector and the second not connected to the interconnector. The non-connection portions can be arranged alternately.

  Moreover, in the solar cell string of this invention, a 1st connection part and a 2nd connection part can each be arrange | positioned in the mutually symmetrical position regarding a semiconductor substrate.

  In the solar cell string of the present invention, the bus bar electrode has three first non-connection portions, and the small cross-sectional area portions can be arranged at positions corresponding to the first non-connection portions located at both ends. .

  Furthermore, this invention is a solar cell module containing the solar cell string in any one of said.

  ADVANTAGE OF THE INVENTION According to this invention, the solar cell with an interconnector and solar cell string which can further improve reduction of the curvature of a solar cell, and the solar cell module containing the solar cell string can be provided.

  Embodiments of the present invention will be described below. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

  FIG. 1 shows a schematic plan view of a preferred example of a light receiving surface which is a first main surface of a p-type silicon substrate 10 as a semiconductor substrate of a solar cell used in the present invention. Here, the silver electrode 13 on the light-receiving surface of the solar cell includes one linear bus bar electrode 13a having a relatively large width, and a plurality of relatively small linear finger electrodes 13b extending from the bus bar electrode 13a. It is composed of The bus bar electrode 13a includes a linear first connection part 51 for fixing and connecting to the interconnector, and a first non-connection part 42 that is a gap that is not connected to the interconnector. The portions 51 and the first non-connecting portions 42 are alternately arranged. Specifically, four first connection portions 51 are formed in one bus bar electrode 13 a shown in FIG. 1, and three first non-connection portions 42 are formed between adjacent first connection portions 51. ing.

  In FIG. 2, the typical top view of a preferable example of the back surface used as the 2nd main surface of the p-type silicon substrate 10 as a semiconductor substrate of the solar cell used for this invention is shown. The aluminum electrode 14 is formed on almost the entire second main surface of the p-type silicon substrate 10, and the silver electrode 16 is formed only on a part of the second main surface of the p-type silicon substrate 10. Here, the silver electrode 16 corresponds to a second connecting portion for connecting to the interconnector, and the aluminum electrode 14 positioned between the silver electrodes 16 arranged in the longitudinal direction of the silver electrode 16 is connected to the interconnector. This corresponds to a second unconnected portion that is not connected. Therefore, the silver electrodes 16 as the second connection portions and the aluminum electrodes 14 as the second non-connection portions are alternately arranged. The back surface as the second main surface of the semiconductor substrate is a main surface opposite to the light receiving surface as the first main surface of the semiconductor substrate.

  In FIG. 3, the typical top view of a preferable example of the interconnector used for this invention is shown. Here, the interconnector 31 has a plurality of small cross-sectional area portions 41 whose cross-sectional areas perpendicular to the longitudinal direction are locally small and a non-small cross-sectional area portion located between the small cross-sectional area portions 41. 61. In the present invention, the interconnector is a member having conductivity, and the cross-sectional area of the cross section perpendicular to the longitudinal direction is locally small. If it has the non-small cross-sectional area part located in, the shape and material will not be specifically limited. In the present invention, the cross-sectional area of the non-small cross-sectional area portion of the interconnector has a larger cross-sectional area perpendicular to the longitudinal direction of the interconnector than the small cross-sectional area portion.

  In FIG. 4, the typical enlarged plan view of the light-receiving surface of a preferable example of the solar cell with an interconnector of this invention is shown. The interconnector 31 shown in FIG. 3 is connected to the first connection portion 51 of the solar cell having the light receiving surface shown in FIG. 1 and the back surface shown in FIG. Is formed. Here, in the solar cell with an interconnector of the present invention, the two small cross-sectional area portions 41 of the interconnector 31 are first non-connected at both ends of the first non-connecting portions 42 arranged on the light receiving surface of the solar cell. It is arranged at a position corresponding to the connection portion 42, and one of the positions corresponding to the non-small cross-sectional area portion 61 is disposed between the first non-connection portions 42 at both ends at the position corresponding to the small cross-sectional area portion 41. A first non-connection portion 42 is disposed.

  As shown in FIG. 4, in the solar cell with an interconnector according to the present invention, not only the first non-connecting portion 42 is disposed at a position corresponding to the small cross-sectional area portion 41, but also between the small cross-sectional area portions 41. The first non-connecting portion 42 is also arranged at a position corresponding to the non-small cross-sectional area portion 61. Therefore, in the solar cell with an interconnector according to the present invention, the p-type silicon substrate 10 and the interconnector in the cooling step after the heating step in which the first connection part 51 of the solar cell and the interconnector 31 are fixed and connected by solder or the like. Even when internal stress is generated in each of the connectors 31, the internal stress can be relieved not only in the small cross-sectional area 41 of the interconnector 31 but also in the non-small cross-sectional area 61 between the small cross-sectional areas 41. In addition, the warpage of the solar cell can be further reduced as compared with the solar cell with an interconnector using the interconnector of Patent Document 1 shown in FIG.

  FIG. 5 shows a schematic cross-sectional view of the solar cell with an interconnector of the present invention shown in FIG. Here, in the solar cell with an interconnector of the present invention, the silver electrode 16 as the second connection portion and the first connection portion 51 are arranged at positions symmetrical to each other with respect to the p-type silicon substrate 10 as the semiconductor substrate. Has been. One of the causes of the warpage of the solar cell is that the internal stress generated in the solar cell due to the difference in thermal expansion between the solar cell and the interconnector differs between the light receiving surface and the back surface of the solar cell. By adopting such a configuration, the internal stress generated in the solar cell due to the difference in thermal expansion between the solar cell and the interconnector can be made substantially equal between the light receiving surface and the back surface of the solar cell.

  Therefore, in the solar cell with an interconnector of the present invention, when internal stress is generated in the solar cell due to the difference in thermal expansion between the solar cell and the interconnector, the solar cell is connected to the solar cell as described in Patent Document 1. In addition to relaxation by free stretching of the small cross-sectional area that is not made, relaxation by free deformation of the non-small cross-sectional area that is not connected to the solar cell, and further, the first connection portion of the light receiving surface of the solar cell and Since the internal stress is substantially equal between the light receiving surface and the back surface of the solar cell by disposing the second connection portion on the back surface at positions symmetrical to each other with respect to the semiconductor substrate, the warpage of the solar cell is reduced. Further improvements can be desired.

  In FIG. 6, typical sectional drawing of a preferable example of the solar cell string of this invention is shown. Here, the solar cell string is formed by connecting a plurality of solar cells with an interconnector of the present invention configured as shown in FIGS. 4 and 5. That is, the other end of the interconnector 31 connected to the light receiving surface of the solar cell 60 with an interconnector of the present invention is the silver electrode 16 as the second connection portion on the back surface of the solar cell 62 with an interconnector of the present invention. It is connected to the. Moreover, in each of the solar cell with interconnector 60 and the solar cell with interconnector 62, the silver electrode 16 as the second connection portion and the first connection portion 51 are respectively related to the p-type silicon substrate 10 as the semiconductor substrate. It arrange | positions in the mutually symmetrical position.

  FIG. 7 shows a schematic plan view of the light receiving surface of the solar cell string of the present invention shown in FIG. Here, in the solar cell string of the present invention, the small cross-sectional area portion 41 of the interconnector 31 has the first non-connecting portions 42 at the both ends of the first non-connecting portions 42 arranged on the light receiving surface of the solar cell 60 with an interconnector. It arrange | positions in the position corresponding to the 1st non-connection part 42 of the both ends among the position corresponding to the connection part 42, and the 1st non-connection part 42 arrange | positioned at the light-receiving surface of the solar cell 62 with an interconnector. And between the 1st non-connection part 42 of the both ends arrange | positioned at the light-receiving surface of the solar cell 60 with an interconnector, one 1st non-connection part 42 in the position corresponding to the non-small cross-sectional area part 61 is provided. Is arranged. Moreover, between the 1st non-connection part 42 of the both ends arrange | positioned at the light-receiving surface of the solar cell 62 with an interconnector, one 1st non-connection part 42 in the position corresponding to the non-small cross-sectional area part 61 is also provided. Is arranged.

  Moreover, the small cross-sectional area part 41 of the interconnector 31 is the position corresponding to the 2nd non-connection part of both ends among the 2nd non-connection parts arrange | positioned at the back surface of the solar cell 60 with an interconnector, and a solar cell with an interconnector. Of the second non-connecting parts arranged on the back surface of 62, the two non-connecting parts are arranged at positions corresponding to the second non-connecting parts at both ends.

  Therefore, in the solar cell string of the present invention, when internal stress occurs in the solar cell due to the difference in thermal expansion between the solar cell and the interconnector, the solar cell with interconnector 60 and the solar cell with interconnector 62 For both the light receiving surface and the back surface, as described in Patent Document 1, relaxation by free stretching of the small cross-sectional area portion 41 not connected to the solar cell and non-small cross-sectional area portion 61 not connected to the solar cell Of the solar cell by arranging the first connection portion of the light receiving surface of the solar cell and the second connection portion of the back surface symmetrical with each other with respect to the semiconductor substrate. Since the effect of making the internal stress approximately equal on the front and back surfaces is obtained, further improvement in reducing the warpage of the solar cell can be expected. .

  The solar cell module of the present invention including the solar cell string of the present invention can be obtained by sealing the solar cell string of the present invention with a sealing material such as EVA by a conventionally known method.

  In addition, although the other description about said embodiment of this invention is the same as the description in the column of said background art, it is not limited to the description. For example, in the present invention, a semiconductor substrate other than the p-type silicon substrate may be used, and the p-type and n-type conductivity types described in the background section above may be interchanged. In the present invention, the first connection portion and the second connection portion are not necessarily silver electrodes. In the present invention, the first non-connecting portion does not need to be a gap, and the second non-connecting portion does not need to be made of an aluminum electrode. Further, in the present invention, the first disposed at a position corresponding to the non-small cross-sectional area portion of the interconnector, which is installed between the first non-connecting portions disposed at positions corresponding to the small cross-sectional area portion of the interconnector. The number of one non-connecting portion is not limited to one and may be two or more.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  ADVANTAGE OF THE INVENTION According to this invention, the solar cell with an interconnector and solar cell string which can further improve reduction of the curvature of a solar cell, and the solar cell module containing the solar cell string can be provided.

It is a typical top view of a preferable example of the light-receiving surface used as the 1st main surface of the semiconductor substrate of the solar cell used for this invention. It is a typical top view of a preferable example of the back surface used as the 2nd main surface of the semiconductor substrate of the solar cell used for this invention. It is a typical top view of a desirable example of an interconnector used for the present invention. It is a typical enlarged plan view of the light-receiving surface of a preferable example of the solar cell with an interconnector of the present invention. It is typical sectional drawing of the solar cell with an interconnector of this invention shown in FIG. It is typical sectional drawing of a preferable example of the solar cell string of this invention. It is a typical enlarged plan view of the light-receiving surface of the solar cell string of the present invention shown in FIG. It is typical sectional drawing of an example of the conventional solar cell. It is a figure for illustrating an example of the manufacturing method of the conventional solar cell. It is a figure for illustrating an example of the manufacturing method of the conventional solar cell module. It is a top view of the light-receiving surface of an example of the solar cell before connecting using the interconnector of patent document 1. It is a top view of the back surface of the solar cell shown in FIG. It is typical sectional drawing of the solar cell string which connected the solar cell which has the light-receiving surface shown in FIG. 11, and the back surface shown in FIG. 12 using the interconnector of patent document 1. FIG. It is a typical enlarged plan view of the light-receiving surface of the solar cell string shown in FIG.

Explanation of symbols

  10 p-type silicon substrate, 11 n + layer, 12 antireflection film, 13 and 16 silver electrode, 13a bus bar electrode, 13b finger electrode, 14 aluminum electrode, 31 interconnector, 41 small cross-sectional area portion, 42 first non-connecting portion , 51 1st connection part, 60,62 Solar cell with an interconnector, 61 Non-small cross-sectional area part.

Claims (9)

A bus bar electrode in which a plurality of first connection portions for connecting to an interconnector and a plurality of first non-connection portions not connected to the interconnector are alternately arranged, and a finger electrode extending from the bus bar electrode, a semiconductor substrate A solar cell with an interconnector including a solar cell provided on the first main surface, wherein an interconnector is connected to the first connection portion of the solar cell,
The interconnector has a plurality of small cross-sectional area portions whose cross-sectional areas perpendicular to the longitudinal direction are locally small, and a non-small cross-sectional area portion located between the small cross-sectional area portions. And
Each of the small cross-sectional area portions is disposed at a position corresponding to the first non-connecting portion,
At least one first non-connecting portion corresponding to the non-small cross-sectional area portion is disposed between the first non-connecting portions located at positions corresponding to the small cross-sectional area portions, Solar cell with interconnector.   On the second main surface opposite to the first main surface of the semiconductor substrate, second connection portions for connecting to the interconnector and second non-connecting portions not connected to the interconnector are alternately arranged. The solar cell with an interconnector according to claim 1, wherein:   3. The solar cell with an interconnector according to claim 2, wherein the first connection portion and the second connection portion are arranged at positions that are symmetrical to each other with respect to the semiconductor substrate.   The bus bar electrode includes three first non-connection portions, and the small cross-sectional area portions are arranged at positions corresponding to the first non-connection portions located at both ends. Item 4. A solar cell with an interconnector according to any one of Items 1 to 3. A bus bar electrode in which a plurality of first connection portions for connecting to an interconnector and a plurality of first non-connection portions not connected to the interconnector are alternately arranged, and a finger electrode extending from the bus bar electrode, a semiconductor substrate A solar cell string in which a plurality of solar cells provided on the first main surface are connected by an interconnector,
The interconnector has a plurality of small cross-sectional area portions whose cross-sectional areas perpendicular to the longitudinal direction are locally small, and a non-small cross-sectional area portion located between the small cross-sectional area portions. And
Each of the small cross-sectional area portions is disposed at a position corresponding to the first non-connecting portion,
At least one first non-connecting portion corresponding to the non-small cross-sectional area portion is disposed between the first non-connecting portions located at positions corresponding to the small cross-sectional area portions, Solar cell string.   On the second main surface opposite to the first main surface of the semiconductor substrate, second connection portions for connecting to the interconnector and second non-connecting portions not connected to the interconnector are alternately arranged. The solar cell string according to claim 5, wherein:   The solar cell string according to claim 6, wherein the first connection part and the second connection part are arranged at positions symmetrical to each other with respect to the semiconductor substrate.   The bus bar electrode includes three first non-connection portions, and the small cross-sectional area portions are arranged at positions corresponding to the first non-connection portions located at both ends. Item 8. The solar cell string according to any one of Items 5 to 7.   The solar cell module containing the solar cell string in any one of Claim 5 to 8.

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