JP2007250623A - 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 interconnector for reducing warpage of the solar cell without increase in the manufacturing steps, and also to provide a solar cell string and a solar cell module. <P>SOLUTION: The solar cell with interconnector is connected at the interconnector to a first connecting portion of the solar cell. A bus bar electrode has a structure that a first non-connecting portion is arranged among the first connecting portions. The first connecting portion and the first non-connecting portion are alternately arranged in the direction orthogonal to the longitudinal direction of the bus bar electrode. The interconnector includes a plurality of small cross-sectional areas where a cross-sectional area of the cross-section perpendicular to the longitudinal direction of the interconnector is locally reduced, and a plurality of non-small cross-sectional areas located among the small cross-sectional areas. The small cross-sectional area is the solar cell with interconnector, solar cell string, and solar cell module including the solar cell string arranged in the first non-connecting portion. <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.

  In FIG. 10, typical sectional drawing of an example of the conventional solar cell is shown. Here, in the solar cell, the n + layer 11 is formed on the light receiving surface of the p-type silicon substrate 10, thereby forming a pn junction between the p-type silicon substrate 10 and the n + layer 11. An antireflection film 12 and a silver electrode 13 are respectively formed on the light receiving surface of the silicon substrate 10. 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. Here, the silver electrode 13 on the light receiving surface of the p-type silicon substrate 10 includes a bus bar electrode for connection to the interconnector and a finger electrode extending from the bus bar electrode. Moreover, the silver electrode 16 on the back surface of the p-type silicon substrate 10 serves as a back surface electrode for connection to the interconnector.

  FIGS. 11A to 11I show an example of a conventional solar cell manufacturing method. First, as shown in FIG. 11A, 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 FIG. 11B, the p-type silicon substrate 10 is obtained by cutting the silicon block 18 with a wire saw.

  Next, the damage layer 19 at the time of slicing the p-type silicon substrate 10 shown in FIG. 11C 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 FIG. 11 (d), a dopant liquid 20 containing a compound containing phosphorus is applied on one main surface (hereinafter referred to as “first main surface”) of the p-type silicon substrate 10. 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 FIG. 11E, 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 the glass layer formed on the first main surface of the p-type silicon substrate 10 during phosphorus diffusion is removed by acid treatment, the first main surface of the p-type silicon substrate 10 as shown in FIG. An antireflection film 12 is formed thereon. 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.

  Then, as shown in FIG. 11G, 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 the second of the p-type silicon substrate 10 is formed. A p + layer 15 is formed on the main surface. 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, as shown in FIG. 11 (h), a silver electrode 16 is formed on the second main surface of the p-type silicon substrate 10. 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, as shown in FIG. 11 (i), a silver electrode 13 is formed on the first main surface of the p-type silicon substrate 10. 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. For example, as disclosed in Patent Document 1, a slit may be provided in the bus bar electrode in order to form the bus bar electrode thick. 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. 10 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.

  FIGS. 12A to 12E show an example of a conventional method for manufacturing a solar cell module. First, as shown to Fig.12 (a), the interconnector 31 which is an electroconductive member is connected on the silver electrode of the 1st main surface of the solar cell manufactured as mentioned above, and a solar cell with an interconnector 30 is produced.

  Next, as shown in FIG.12 (b), the other end of the interconnector 31 which arrange | positions the solar cell 30 with an interconnector in a line, and is connected to the silver electrode of the 1st main surface of the solar cell 30 with an interconnector. Is connected to the silver electrode on the second main surface of the solar cell 30 with another interconnector to produce a solar cell string 34.

  Next, as shown in FIG. 12C, the solar cell strings are arranged side by side, and the interconnector 31 protruding from both ends of the solar cell string and the interconnector 31 protruding from both ends of the other solar cell string are electrically conductive. The solar cell strings are connected to each other by connecting in series using the wiring member 33 as a member.

  Subsequently, as shown in FIG. 12 (d), the connected solar cell string 34 is sandwiched between EVA (ethylene vinyl acetate) films 36 as a sealing material, and then between a glass plate 35 and a back film 37. Pinch. 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 is sealed in the EVA. Thereby, a solar cell module is produced.

Then, as shown in FIG.12 (e), a solar cell module is arrange | positioned in the aluminum frame 40, and the terminal box 38 provided with the cable 39 is attached to a 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 2001-44459 A 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 the silicon substrate, when the solar cell string is formed, the cooling after the heating process in which the bus bar electrode on the light receiving surface of the solar cell and the interconnector made of copper are fixed and connected by solder or the like. In the process, the difference in thermal expansion coefficient between the silicon substrate of the solar cell and the interconnector (the thermal expansion coefficient of silicon is 3.5 × 10 ⁻⁶ / K, whereas copper is 17.6 × 10 ⁻⁶ / K, 5 times There is a problem that the solar cell is warped.

  This is because, in the above heating step, after fixing the solar cell and the interconnector, when the solar cell and the interconnector in a heated state are cooled to room temperature, the interconnector contracts more than the solar cell. It is thought that the concave warpage occurred in the battery. 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.

  Therefore, Patent Document 2 discloses a method of providing a small cross-sectional area part whose cross-sectional area is locally reduced 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 Document 2, when a tensile stress is applied to the interconnector, a small cross-sectional area portion that is relatively weak compared to other portions is stretched to reduce the warpage of the solar cell. be able to.

  FIG. 15 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. 13 and the back surface shown in FIG. 14 are connected using the interconnector described in Patent Document 2, and FIG. FIG. 16 shows a schematic plan view of the light receiving surface of the solar cell string shown.

  Here, as shown in FIG. 13, the silver electrode 13 on the light-receiving surface of the solar cell has one linear bus bar electrode 13 a having a relatively large width and a plurality of linear shapes having a relatively small width extending from the bus bar electrode 13 a. Finger electrode 13b. 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 which is a gap that is not connected to the interconnector. The first connection part 51 and the 1st non-connecting part 42 are arranged by turns along the longitudinal direction of bus bar electrode 13a.

  As shown in FIG. 14, 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 becomes a second connection part for fixing and connecting to the interconnector, and the aluminum electrode 14 positioned between the silver electrodes 16 becomes a second non-connecting part 14a not connected to the interconnector. And the back surface electrode 60 is formed from the silver electrode 16 as a 2nd connection part, and the 2nd non-connection part 14a. 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. 15, in the solar cell string using the interconnector described in Patent Document 2, the interconnector 31 fixedly connected to the first connection part 51 of the light receiving surface of the solar cell by 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. 15, the description of the n + layer and the p + layer is omitted.

  Further, as shown in FIGS. 15 and 16, the small cross-sectional area 41 of the interconnector 31 is disposed in the first non-connecting portion 42 and the second non-connecting portion 14 a of the solar cell, respectively. The small cross-sectional area 41 is not fixed with 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, in the above method, when connecting the interconnector 31 to the solar cell, the small cross-sectional area 41 of the interconnector 31, the first non-connecting portion 42 of the light receiving surface of the solar cell, and the second non-connecting portion 14a of the back surface. Are strictly aligned and connected, which increases the number of processes and decreases productivity. Moreover, if the small cross-sectional area part 41 of the interconnector 31, the 1st non-connecting part 42 of the light-receiving surface of a solar cell, and the 2nd non-connecting part 14a of a back surface are connected by shifting | deviating, the effect of the curvature reduction of a solar cell will be effective. There was a problem that it could not be obtained sufficiently.

  Then, the objective of this invention is providing the solar cell with an interconnector and solar cell string which can reduce the curvature of a solar cell, without increasing the number of processes, and a solar cell module.

  According to the present invention, a bus bar electrode including a first connection portion for connecting to an interconnector and a first non-connection portion not connected to the interconnector, and a finger electrode extending from the bus bar electrode are provided on the first main surface of the semiconductor substrate. The interconnector is connected to the first connection portion of the solar cell, and the bus bar electrode has the first non-connection portion disposed between the first connection portions. The first connecting portion and the first non-connecting portion are alternately arranged in a direction perpendicular to the longitudinal direction of the bus bar electrode, and the interconnector has a cross-sectional area perpendicular to the longitudinal direction of the interconnector. Has a plurality of small cross-sectional area portions that are locally small, and a non-small cross-sectional area portion located between the small cross-sectional area portions, and the small cross-sectional area portion is disposed in the first non-connecting portion. Inter A connector with a solar battery.

  The present invention also provides a bus bar electrode composed of a first connecting portion for connecting to an interconnector and a first non-connecting portion not connected to the interconnector, and a finger electrode extending from the bus bar electrode. A back electrode comprising a second connection part for connecting to the interconnector and a second non-connecting part not connected to the interconnector on the second principal surface opposite to the first principal surface of the semiconductor substrate. A solar cell with an interconnector in which an interconnector is connected to a second connection portion of the solar cell, and the back electrode has a second non-connection portion disposed between the second connection portions. The second connecting portion and the second non-connecting portion are alternately arranged in a direction orthogonal to the longitudinal direction of the back electrode, and the interconnector has a cross section perpendicular to the longitudinal direction of the interconnector. A plurality of small cross-sectional area portions whose area is locally reduced, and a non-small cross-sectional area portion located between the small cross-sectional area portions, the small cross-sectional area portion being a second non-connecting portion It is the solar cell with the interconnector arrange | positioned. Here, the bus bar electrode may have a configuration in which the first non-connection portion is disposed between the first connection portions, and the first connection portion and the first non-connection portion are orthogonal to the longitudinal direction of the bus bar electrode. It may be arranged alternately in the direction. Moreover, it is preferable that the 1st connection part and the 2nd connection part are each formed in the position which is mutually symmetrical with respect to a semiconductor substrate.

  The present invention also provides a bus bar electrode composed of a first connecting portion for connecting to an interconnector and a first non-connecting portion not connected to the interconnector, and a finger electrode extending from the bus bar electrode. A solar cell string in which a plurality of solar cells provided on a surface are connected by an interconnector, and the bus bar electrode has a configuration in which a first non-connection portion is disposed between first connection portions, The one connection part and the first non-connection part are alternately arranged in a direction orthogonal to the longitudinal direction of the bus bar electrode, and the cross-sectional area of the cross-section perpendicular to the longitudinal direction of the interconnector is locally reduced. The solar cell string includes a plurality of small cross-sectional area portions and a non-small cross-sectional area portion positioned between the small cross-sectional area portions, and the small cross-sectional area portion is disposed in the first non-connecting portion. .

  The present invention also provides a bus bar electrode composed of a first connecting portion for connecting to an interconnector and a first non-connecting portion not connected to the interconnector, and a finger electrode extending from the bus bar electrode. A back electrode comprising a second connection part for connecting to the interconnector and a second non-connecting part not connected to the interconnector on the second principal surface opposite to the first principal surface of the semiconductor substrate. A solar cell string in which a plurality of solar cells are connected by an interconnector, and the back electrode has a configuration in which a second non-connection portion is disposed between the second connection portions, and a second connection And the second non-connecting portion are alternately arranged in a direction perpendicular to the longitudinal direction of the back electrode, and the interconnector has a locally reduced cross-sectional area perpendicular to the longitudinal direction of the interconnector. A plurality of small cross-sectional area portions and a non-small cross-sectional area portion located between the small cross-sectional area portions, and the small cross-sectional area portion is a solar cell string disposed in the second non-connecting portion is there. Here, the bus bar electrode may have a configuration in which the first non-connection portion is disposed between the first connection portions, and the first connection portion and the first non-connection portion are orthogonal to the longitudinal direction of the bus bar electrode. It may be arranged alternately in the direction. Moreover, it is preferable that the 1st connection part and the 2nd connection part are each formed in the position which is mutually symmetrical with respect to a semiconductor substrate.

  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 reduce the curvature of a solar cell, without increasing the number of processes, and a solar cell module 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.

  In FIG. 1, the typical top view of a preferable example of the light-receiving surface of the solar cell used for this invention is shown. Here, on the first main surface of the p-type silicon substrate 10 serving as the light receiving surface of the solar cell of the present invention, a relatively wide linear bus bar electrode 13a extending in the left-right direction of the paper surface, and the bus bar electrode 13a to the paper surface. And a plurality of narrow linear finger electrodes 13b extending in the vertical direction. The bus bar electrode 13a includes a first connection portion 51 made of a silver electrode for fixing and connecting to the interconnector, and a first non-connection portion 42 that is a gap that is not connected to the interconnector. Here, the bus bar electrode 13a has a configuration in which a first non-connecting portion 42 is disposed between the first connecting portions 51, and the first connecting portion 51 and the first non-connecting portion 42 are connected to the bus bar electrode 13a. They are alternately arranged in a direction perpendicular to the longitudinal direction.

  FIG. 2 shows a schematic plan view of a preferred example of the back surface of the solar cell shown in FIG. Here, an aluminum electrode 14 is formed on substantially the entire second main surface of the p-type silicon substrate 10 which is the back surface of the solar cell of the present invention, and a silver electrode 16 is formed so as to extend in the left-right direction on the paper surface. ing. Here, the silver electrode 16 serves as a second connection part for fixing and connecting to the interconnector, and the aluminum electrode 14 disposed between the two silver electrodes 16 is not connected to the interconnector. 14a. Moreover, the back electrode 60 is comprised from the silver electrode 16 as a 2nd connection part, and the 2nd non-connection part 14a. Here, the back surface electrode 60 has a configuration in which the second non-connection portion 14a is disposed between the silver electrodes 16 as the second connection portions, and the second non-connection portion and the silver electrodes 16 as the second connection portions are arranged. The connection portions 14 a are alternately arranged in a direction orthogonal to the longitudinal direction of the back electrode 60.

  FIG. 3 is a schematic cross-sectional view of a solar cell having the light receiving surface shown in FIG. 1 and the back surface shown in FIG. FIG. 3 schematically shows an example of a cross section along a direction orthogonal to the longitudinal direction of the bus bar electrode of the solar cell. Here, as shown in FIG. 3, the silver electrode 16 as the first connection portion 51 and the second connection portion is formed at positions symmetrical to each other with respect to the p-type silicon substrate 10 as the semiconductor substrate.

  In FIG. 4, the typical top view of a preferable example of the interconnector used for this invention is shown. Here, the interconnector 31 includes a plurality of small cross-sectional area portions 41 in which the cross-sectional area of the cross section perpendicular to the longitudinal direction of the interconnector 31 is locally small, and a non-small size located between the small cross-sectional area portions 41. And a cross-sectional area 61. In the present invention, the interconnector is a member having conductivity, and includes a plurality of small cross-sectional area portions whose cross-sectional area perpendicular to the longitudinal direction is locally reduced, and a small cross-sectional area portion. If it has the non-small cross-sectional area part located in between, 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.

  FIG. 5A shows a schematic plan view of a preferred example of the solar cell with an interconnector of the present invention. Here, in the solar cell with an interconnector of the present invention, the interconnector 31 shown in FIG. 4 is fixed to the first connection part 51 of the light receiving surface of the solar cell having the light receiving surface shown in FIG. 1 and the back surface shown in FIG. It is a connected configuration. In the solar cell with an interconnector of the present invention shown in FIG. 5A, for example, as shown in the schematic enlarged plan view of FIG. 5B, the small cross-sectional area 41 of the interconnector 31 is the first light receiving surface. The interconnector 31 is connected so as to be disposed in the non-connecting portion 42.

  FIG. 6 (a) shows a schematic plan view of another preferred example of the solar cell with an interconnector of the present invention. Here, in the solar cell with an interconnector of the present invention, the interconnector 31 shown in FIG. 4 is provided on the silver electrode 16 as the second connecting portion on the back surface of the solar cell having the light receiving surface shown in FIG. 1 and the back surface shown in FIG. The configuration is fixed and connected. In the solar cell with an interconnector of the present invention shown in FIG. 6 (a), for example, as shown in the schematic enlarged plan view of FIG. The interconnector 31 is connected so that it may be arrange | positioned at the connection part 14a.

  Thus, in the solar cell with an interconnector according to the present invention, the small cross-sectional area 41 having a relatively low strength compared to the other portions of the interconnector 31 is used as the first non-connection portion 42 or the second non-connection portion 14a. Since the small cross-sectional area 41 is in a free state without being fixed, the small cross-sectional area 41 is freely deformed to relieve the stress, thereby reducing the warpage of the solar cell. be able to.

  Moreover, in the solar cell with an interconnector of the present invention, the first connecting portion 51 that is a connecting portion between the interconnector 31 and the solar cell and the silver electrode 16 as the second connecting portion are respectively semiconductors on the light receiving surface and the back surface of the solar cell. When the p-type silicon substrate 10 as a substrate is formed at a symmetrical position, the stress generated due to the difference in thermal expansion coefficient between the interconnector 31 and the p-type silicon substrate of the solar cell is received by the solar cell. Since the surface and the back surface are substantially equal, and the same force is applied to the solar cell from each of the light receiving surface and the back surface of the solar cell, warpage generated in the solar cell can be further reduced.

  Furthermore, when manufacturing the solar cell with an interconnector according to the present invention, the first non-connected portion 42 and the second non-connected portion 14a of the solar cell are continuously formed in the longitudinal direction of the bus bar electrode 13a and the back electrode 60, respectively. Therefore, the interconnector 31 can be connected without strict alignment between the small cross-sectional area 41 of the interconnector 31 and the first non-connected portion 42 or the second non-connected portion 14a of the solar cell. .

  Therefore, in the solar cell with an interconnector of the present invention, the warpage of the solar cell can be reduced without increasing the number of steps.

  Moreover, in the solar cell with an interconnector of the present invention, the light receiving surface and / or the back surface of the solar cell with an interconnector of the present invention is required even when the number of small cross-sectional areas 41 of the interconnector 31 needs to be increased or decreased. The number of small cross-sectional area portions 41 of the interconnector 31 can be changed without changing the electrode shape.

  In FIG. 7, typical sectional drawing of another preferable example of the solar cell string of this invention is shown. Here, the solar cell string is configured by connecting a plurality of solar cells with an interconnector of the present invention shown in FIG. 5 (a) or FIG. 6 (a). That is, in the adjacent solar cell with an interconnector of the present invention, one end of the interconnector 31 that connects the interconnector solar cells is the silver electrode 16 as the second connection portion on the back surface of the first solar cell with interconnector 80. The other end of the interconnector 31 is connected to the first connection part 51 on the light receiving surface of the solar cell 81 with the second interconnector.

  FIG. 8 is a schematic plan view of the light receiving surface of the solar cell string of the present invention shown in FIG. FIG. 9 shows a schematic plan view of the back surface of the solar cell string of the present invention shown in FIG. Here, in the solar cell string of the present invention shown in FIGS. 8 and 9, the interconnector 31 has a small cross-sectional area 41 of the interconnector 31 and a first non-connecting portion 42 and a back surface of the light receiving surface of the solar cell, respectively. The second non-connection portion 14a is connected so as to be disposed.

  As described above, in the solar cell string of the present invention, the small cross-sectional area portion 41 that is relatively weak compared to the other portions of the interconnector 31 is disposed in the first non-connection portion 42 and the second non-connection portion 14a. Since the small cross-sectional area 41 is not fixed and is in a free state, the small cross-sectional area 41 can be freely deformed to relieve the stress, thereby reducing the warpage of the solar cell. it can.

  Further, in the solar cell string of the present invention, the first connection part 51 which is a connection part between the interconnector 31 and the solar cell and the silver electrode 16 as the second connection part are respectively used as a semiconductor substrate on the light receiving surface and the back surface of the solar cell. When the p-type silicon substrate 10 is formed at a symmetrical position, the stress generated due to the difference in thermal expansion coefficient between the interconnector 31 and the p-type silicon substrate of the solar cell is different from that of the light-receiving surface of the solar cell. Since it becomes substantially equal on the back surface and equal force acts on the solar cell from each of the light receiving surface and the back surface of the solar cell, warpage occurring in the solar cell can be further reduced.

  Furthermore, when manufacturing the solar cell string of the present invention, the first non-connected portion 42 and the second non-connected portion 14a of the solar cell are formed continuously in the longitudinal direction of the bus bar electrode 13a and the back electrode 60, respectively. Thus, the interconnector 31 can be connected without strict alignment between the small cross-sectional area 41 of the interconnector 31 and the first non-connected portion 42 or the second non-connected portion 14a of the solar cell.

  Therefore, in the solar cell string of the present invention, the warpage of the solar cell can be reduced without increasing the number of steps.

  Further, in the solar cell string of the present invention, even when it is necessary to increase or decrease the number of small cross-sectional area portions 41 of the interconnector 31, without changing the electrode shape on the light receiving surface and / or the back surface of the solar cell. It is possible to cope with a change in the number of small cross-sectional area portions 41 of the interconnector 31.

  The solar cell module 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.

  The description other than the above is the same as the description in the background art section above, but 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 do not necessarily need to be silver electrodes, the first non-connection portion does not need to be a gap, and the second non-connection portion is made of an aluminum electrode. There is no need to be.

  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 reduce the curvature of a solar cell, without increasing the number of processes, and a solar cell module can be provided.

It is a typical top view of a preferable example of the light-receiving surface of the solar cell used for this invention. It is a typical top view of a preferable example of the back surface of the solar cell shown in FIG. It is typical sectional drawing of the solar cell which has the light-receiving surface shown in FIG. 1, and the back surface shown in FIG. It is a typical top view of a desirable example of an interconnector used for the present invention. (A) is a typical top view of a preferable example of the solar cell with an interconnector of this invention, (b) is a typical enlarged plan view of the 1st non-connecting part vicinity shown to (a). (A) is a typical top view of another example of the preferable solar cell with an interconnector of this invention, (b) is a typical enlarged plan view of the 2nd non-connection part vicinity shown to (a). . It is typical sectional drawing of another preferable example of the solar cell string of this invention. It is a typical top view of the light-receiving surface of the solar cell string of this invention shown in FIG. It is a typical top view of the back surface of the solar cell string of this invention shown in FIG. It is typical sectional drawing of an example of the conventional solar cell. It is a figure which shows an example of the manufacturing method of the conventional solar cell. It is a figure which shows an example of the manufacturing method of the conventional solar cell module. It is a typical top view of the light-receiving surface of the conventional solar cell. It is a typical top view of the back surface of the conventional solar cell. It is typical sectional drawing of an example of the solar cell string which connected the solar cell which has the light-receiving surface shown in FIG. 13, and the back surface shown in FIG. FIG. 16 is a schematic enlarged plan view of a light receiving surface of the solar cell string shown in FIG. 15.

Explanation of symbols

10 p-type silicon substrate, 11 n + layer, 12 antireflection film, 13, 16 silver electrode, 1
3a busbar electrode, 13b finger electrode, 14 aluminum electrode, 14a second non-connecting portion, 15 p + layer, 17 silicon ingot, 18 silicon block, 20 dopant liquid, 30 solar cell, 31 interconnector, 33 wiring material, 34 solar Battery string, 35 Glass plate, 36 EVA film, 37 Back film, 38 Terminal box, 39 Cable, 40 Aluminum frame, 41 Small cross-sectional area, 42 First non-connection, 51 First connection, 60 Back electrode, 61 Non-small cross-sectional area part, 80 1st solar cell, 81 2nd solar cell.

Claims (9)

Provided on the first main surface of the semiconductor substrate are a bus bar electrode composed of a first connecting portion for connecting to the interconnector and a first non-connecting portion not connected to the interconnector, and a finger electrode extending from the bus bar electrode. A solar cell with an interconnector including a solar cell, wherein an interconnector is connected to the first connection part of the solar cell,
The bus bar electrode has a configuration in which the first non-connection portion is disposed between the first connection portions,
The first connection portion and the first non-connection portion are alternately arranged in a direction orthogonal to the longitudinal direction of the bus bar electrode,
The interconnector includes a plurality of small cross-sectional area portions in which a cross-sectional area perpendicular to the longitudinal direction of the interconnector is locally small, and a non-small cross-sectional area portion positioned between the small cross-sectional area portions, , And
The solar cell with an interconnector, wherein the small cross-sectional area portion is disposed in the first non-connecting portion. A bus bar electrode composed of a first connection part for connecting to the interconnector and a first non-connection part not connected to the interconnector, and a finger electrode extending from the bus bar electrode are provided on the first main surface of the semiconductor substrate, On the second main surface opposite to the first main surface of the semiconductor substrate, a back electrode comprising a second connecting portion for connecting to the interconnector and a second non-connecting portion not connected to the interconnector is provided. A solar cell with an interconnector including a solar cell, wherein an interconnector is connected to the second connection part of the solar cell,
The back electrode has a configuration in which the second non-connecting portion is disposed between the second connecting portions,
The second connection portion and the second non-connection portion are alternately arranged in a direction orthogonal to the longitudinal direction of the back electrode,
The interconnector includes a plurality of small cross-sectional area portions in which a cross-sectional area perpendicular to the longitudinal direction of the interconnector is locally small, and a non-small cross-sectional area portion located between the small cross-sectional area portions, , And
The solar cell with an interconnector, wherein the small cross-sectional area portion is arranged in the second non-connecting portion. The bus bar electrode has a configuration in which the first non-connection portion is disposed between the first connection portions,
The solar cell with an interconnector according to claim 2, wherein the first connection portion and the first non-connection portion are alternately arranged in a direction orthogonal to a longitudinal direction of the bus bar electrode.   4. The solar cell with an interconnector according to claim 2, wherein the first connection portion and the second connection portion are formed at positions that are symmetrical to each other with respect to the semiconductor substrate. 5. Provided on the first main surface of the semiconductor substrate are a bus bar electrode composed of a first connecting portion for connecting to the interconnector and a first non-connecting portion not connected to the interconnector, and a finger electrode extending from the bus bar electrode. A solar cell string in which a plurality of solar cells are connected by an interconnector,
The bus bar electrode has a configuration in which the first non-connection portion is disposed between the first connection portions,
The first connection portion and the first non-connection portion are alternately arranged in a direction orthogonal to the longitudinal direction of the bus bar electrode,
The interconnector includes a plurality of small cross-sectional area portions in which a cross-sectional area perpendicular to the longitudinal direction of the interconnector is locally small, and a non-small cross-sectional area portion located between the small cross-sectional area portions, , And
The solar cell string, wherein the small cross-sectional area is disposed in the first non-connecting portion. A bus bar electrode composed of a first connection part for connecting to the interconnector and a first non-connection part not connected to the interconnector, and a finger electrode extending from the bus bar electrode are provided on the first main surface of the semiconductor substrate, On the second main surface opposite to the first main surface of the semiconductor substrate, a back electrode comprising a second connecting portion for connecting to the interconnector and a second non-connecting portion not connected to the interconnector is provided. A solar cell string in which a plurality of solar cells are connected by an interconnector,
The back electrode has a configuration in which the second non-connecting portion is disposed between the second connecting portions,
The second connection portion and the second non-connection portion are alternately arranged in a direction orthogonal to the longitudinal direction of the back electrode,
The interconnector includes a plurality of small cross-sectional area portions in which a cross-sectional area perpendicular to the longitudinal direction of the interconnector is locally small, and a non-small cross-sectional area portion located between the small cross-sectional area portions, , And
The solar cell string, wherein the small cross-sectional area portion is disposed in the second non-connecting portion. The bus bar electrode has a configuration in which the first non-connection portion is disposed between the first connection portions,
The solar cell string according to claim 6, wherein the first connection portions and the first non-connection portions are alternately arranged in a direction orthogonal to a longitudinal direction of the bus bar electrode.   The solar cell string according to claim 6 or 7, wherein the first connection part and the second connection part are formed at positions symmetrical to each other with respect to the semiconductor substrate.   The solar cell module containing the solar cell string in any one of Claim 5 to 8.

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