JP2007288113A - Solar cell, solar cell string and solar cell module - Google Patents

Abstract

Provided are a solar cell, a solar cell string, and a solar cell module that can reduce warpage of a solar cell, reduce shadow loss, and improve printability during mass production.
A bus bar electrode and a plurality of linear finger electrodes extending from the bus bar electrode are provided on a first main surface of a semiconductor substrate, and the bus bar electrode includes a band-shaped portion having a hollow portion, A region where the hollow portion exists in the longitudinal direction of the bus bar electrode is defined as a first unconnected portion that is not connected to the interconnector, and a region other than the first unconnected portion in the longitudinal direction of the bus bar electrode is connected to the interconnector. A solar cell, a solar cell string, and a solar cell module in which first connection portions and first non-connection portions are alternately arranged in the longitudinal direction of the bus bar electrode.
[Selection] Figure 1

Description

  The present invention relates to a solar cell, 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, 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.

  9A to 9I show an example of a conventional solar cell manufacturing method. First, as shown in FIG. 9A, a silicon ingot 17 obtained by recrystallizing a p-type silicon crystal raw material after being melted in a crucible is cut into silicon blocks 18. Next, as shown in FIG. 9B, 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. 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 FIG. 9D, 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. 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 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. 9G, 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. 9H, 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. 9 (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. 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 to Fig.10 (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.

  Next, as shown in FIG. 10B, the other end of the interconnector 31 in which the solar cells 30 to which the interconnectors are connected is arranged in a row and is connected to the silver electrode on the first main surface of the solar cells 30. Is connected to the silver electrode on the second main surface of another solar cell 30 to produce a solar cell string 34.

  Next, as shown in 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 interconnector 31 protruding from both ends of the other solar cell string 34 Are connected in series using the wiring member 33 which is a conductive member, thereby connecting the solar cell strings to each other.

  Subsequently, as shown in FIG. 10 (d), the connected solar cell string 34 is sandwiched between EVA (ethylene vinyl acetate) films 36 as a sealing material, and then between the glass plate 35 and the 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.10 (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 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 1 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 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. 11 is a schematic cross-sectional view of an example of a solar cell string in which solar cells having the light receiving surface electrode shown in FIG. 11 and the back electrode shown in FIG. 12 are connected using the interconnector described in Patent Document 1. FIG. 14 shows a schematic plan view of the light receiving surface of the solar cell string shown in FIG. 13 and shown in FIG.

  Here, as shown in FIG. 11, the silver electrode 13 on the light-receiving surface that is the first main surface of the p-type silicon substrate 10 of the solar cell is composed of one linear bus bar electrode 13a and a bus bar electrode having a relatively large width. A plurality of linear finger electrodes 13b extending from 13a and having a relatively small width. The bus bar electrode 13a includes a linear first connection portion 51 for fixing and connecting to the interconnector, and a first non-connection portion 42 not connected to the interconnector. 1 non-connecting portions 42 are alternately arranged along the longitudinal direction of the bus bar electrodes 13a.

  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 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. 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 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 solar cell constituting this solar cell string, since the width of the first non-connecting portion 42 is larger than the width of the first connecting portion 51, the shadow loss increases, and the printability at the time of mass production There was a problem that decreased.

  Accordingly, an object of the present invention is to provide a solar cell, a solar cell string, and a solar cell module that can reduce warpage of the solar cell, reduce shadow loss, and improve printability during mass production. There is to do.

  The present invention is provided with a bus bar electrode and a plurality of linear finger electrodes extending from the bus bar electrode on the first main surface of the semiconductor substrate, and the bus bar electrode includes a band-shaped portion having a hollow portion, A region where the hollow portion exists in the longitudinal direction of the bus bar electrode is defined as a first unconnected portion that is not connected to the interconnector, and a region other than the first unconnected portion in the longitudinal direction of the bus bar electrode is connected to the interconnector. In this solar cell, the first connection portion and the first non-connection portion are alternately arranged in the longitudinal direction of the bus bar electrode.

  Here, in the solar cell 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 non-connector not connected to the interconnector. The connection portions may be formed alternately.

  Moreover, in the solar cell of this invention, it is preferable that the 1st connection part and the 2nd connection part are each formed in the mutually symmetrical position regarding a semiconductor substrate.

  In the solar cell of the present invention, it is preferable that the bus bar electrode has a plurality of hollow portions, and the intervals between the adjacent hollow portions are equal. In the present invention, “equal interval” means that the absolute value of the difference between the maximum length and the minimum length among all the intervals of the adjacent hollow portions is 0.5 mm or less. .

  Further, the present invention is a solar cell string in which a plurality of the solar cells are connected, and in the adjacent solar cells, the first connection portion of the first solar cell and the second connection portion of the second solar cell. Are solar cell strings connected to the interconnector.

  Here, in the solar cell string of the present invention, the cross-sectional area of the interconnector is locally reduced in at least one of the location corresponding to the first non-connecting portion and the location corresponding to the second non-connecting portion. It is preferable to have a small cross-sectional area portion.

  Further, in the solar cell string of the present invention, the interconnector has a cross-sectional area of the interconnector that is locally reduced at all the locations corresponding to the first non-connecting portion and the location corresponding to the second non-connecting portion. It is preferable to have a small cross-sectional area.

  In the solar cell string of the present invention, it is preferable that the interconnector has a small cross-sectional area part in which the cross-sectional area of the interconnector is locally reduced in at least one part corresponding to the hollow part.

  In the solar cell string of the present invention, it is preferable that the interconnector has a small cross-sectional area part in which the cross-sectional area of the interconnector is locally reduced at all the parts corresponding to the hollow part.

  Moreover, in the solar cell string of the present invention, the bus bar electrode has a plurality of hollow portions, and at least one interval between the end portion of the first main surface and the hollow portion adjacent to the end portion of the first main surface. The interval is preferably narrower than the interval between adjacent hollow portions.

  Furthermore, the present invention is a solar cell module in which any of the above solar cell strings is sealed with a sealing material.

  According to the present invention, it is possible to provide a solar cell, a solar cell string, and a solar cell module that can reduce warpage of a solar cell, reduce shadow loss, and improve printability during mass production. Can do.

  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 electrode shape of the light-receiving surface of the solar cell of this invention is shown. FIG. 2 shows a schematic enlarged plan view of the electrode shape of the light receiving surface of the solar cell shown in FIG. As shown in FIG. 1, on the first main surface of the p-type silicon substrate that is 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 on the paper surface, and the bus bar electrode A silver electrode 13 comprising a plurality of narrow linear finger electrodes 13b extending from 13a in the vertical direction of the paper surface is provided.

  Here, as shown in FIGS. 1 and 2, the bus bar electrode 13a includes a band-shaped portion having a hollow portion, and the region where the hollow portion 42a exists in the longitudinal direction of the bus bar electrode 13a is not connected to the interconnector. When the first connecting portion 42 is used as the first connecting portion 51 for connecting a region other than the first non-connecting portion 42 to the interconnector in the longitudinal direction of the bus bar electrode 13a, the first connection is made in the longitudinal direction of the bus bar electrode 13a. The portions 51 and the first non-connecting portions 42 are alternately arranged.

  As shown in FIG. 1 and FIG. 2, in the solar cell of the present invention, the bus bar electrode 13a in the first non-connecting portion 42 is wider in the width direction than the solar cell having the light receiving surface electrode having the shape shown in FIG. It does not swell greatly. Therefore, in the solar cell of the present invention, the area where the light receiving surface is hidden by the bus bar electrode 13a can be reduced as compared with the solar cell having the light receiving surface electrode having the shape shown in FIG. Can do. In addition, when the bus bar electrode 13a is formed by using the screen printing method, the width of the bus bar electrode 13a in the first non-connecting portion 42 can be narrowed, so that the blur at the time of screen printing is reduced and the mass production is reduced. Printability is improved.

  FIG. 3 shows a schematic plan view of a preferred example of the electrode shape on 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 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. Yes. Here, the silver electrode 16 serves as a second connection portion 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. Part 14a. The silver electrodes 16 as the second connection portions and the second non-connection portions 14 a are alternately arranged in the longitudinal direction of the silver electrodes 16.

  In the solar cell of the present invention, for example, as shown in FIGS. 1 and 3, the silver electrodes 16 as the first connection portion 51 and the second connection portion are symmetrical with respect to the p-type silicon substrate 10 as the semiconductor substrate, respectively. It is preferable that it is formed at a position. In this case, in the cooling process after the connection between the solar cell and the interconnector, the stress generated due to the difference in thermal expansion coefficient between the interconnector and the solar cell is almost equal between the light receiving surface and the back surface of the solar cell. Since equal force acts on the solar cell from each of the light receiving surface and the back surface of the solar cell, the warp generated in the solar cell tends to be reduced.

  In the solar cell of the present invention, the bus bar electrode 13a has a plurality of (for example, three or more) hollow portions 42a, and it is preferable that the intervals between the adjacent hollow portions 42a be equal. In this case, it tends to be easy to process an interconnector having a small cross-sectional area portion to be described later for connection to the solar cell of the present invention. That is, when the intervals between the adjacent hollow portions 42a are equal, it is possible to form the small cross-sectional area portions of the interconnector at equal intervals. It tends to be.

  In FIG. 4, the typical top view of a preferable example of the interconnector for connecting to the solar cell of this invention is shown. Here, the interconnector 31 has 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. In the present invention, the interconnector is a member having conductivity, and if it has a small cross-sectional area portion in which the cross-sectional area of the cross section perpendicular to the longitudinal direction is locally small, its shape The material is not particularly limited. Further, as described above, it is preferable that the small cross-sectional area portions 41 of the interconnector 31 shown in FIG. 4 are formed at equal intervals.

  In FIG. 5, typical sectional drawing of a preferable example of the solar cell string of this invention is shown. FIG. 6 shows a schematic plan view when the solar cell string of the present invention shown in FIG. 5 is viewed from the light receiving surface side. FIG. 7 shows a schematic enlarged plan view of the vicinity of the first non-connection portion of the solar cell string of the present invention shown in FIGS. 5 and 6. Here, the solar cell string of the present invention includes a plurality of solar cells of the present invention having the light receiving surface electrode having the shape shown in FIG. 1 and the back surface electrode having the shape shown in FIG. 3, using the interconnector shown in FIG. It has become the composition.

  In the solar cell string of the present invention shown in FIGS. 5 to 7, one end of the interconnector 31 is fixedly connected to the first connection part 51 of the first solar cell 80, and the other end of the interconnector 31 is connected. It is fixedly connected to the silver electrode 16 as the second connection portion of the second solar cell 81. In the interconnector 31, the small cross-sectional area 41 of the interconnector 31 has a hollow portion 42 a of the first non-connection portion of the light receiving surface of the first solar cell 80 and a second non-connection of the back surface of the second solar cell 81. It connects so that it may be arrange | positioned at the part 14a. Moreover, as shown in FIG. 5, in the 1st solar cell 80 and the 2nd solar cell 81, the 1st connection part 51 and the silver electrode 16 as a 2nd connection part are respectively on the light-receiving surface and back surface of a solar cell. Each is formed in a symmetrical position with respect to the p-type silicon substrate 10 as a semiconductor substrate.

  As described above, in the solar cell string of the present invention, the small cross-sectional area portion 41 having relatively weak strength as compared with other portions of the interconnector 31 includes the hollow portion 42a and the second non-connecting portion 14a of the first non-connecting portion. Since the small cross-sectional area 41 is not fixed and is in a free state, the small cross-sectional area 41 is freely deformed to relieve the stress, thereby reducing the warpage of the solar cell. can do.

  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. The p-type silicon substrate 10 is preferably formed at a symmetrical position. In this case, 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 becomes substantially equal between the light receiving surface and the back surface of the solar cell, and the light receiving surface and the back surface of the solar cell. Since an equal force is applied to the solar cell from each of the above, warpage occurring in the solar cell can be further reduced.

  Moreover, in the solar cell string of this invention, from a viewpoint of reducing the curvature which arises in a solar cell, the interconnector 31 is the location corresponding to the 1st non-connecting part 42, and the location corresponding to the 2nd non-connecting part 14a. It is preferable to connect so as to have the small cross-sectional area 41 of the interconnector 31 at least at one place, and to all the places corresponding to the first non-connecting portion 42 and the locations corresponding to the second non-connecting portion 14a. It is more preferable to connect so as to have a small cross-sectional area 41 of the interconnector 31.

  In particular, in the above-described solar cell string of the present invention, the interconnector 31 has a location corresponding to the hollow portion 42 a of the first solar cell 80 and a location corresponding to the second non-connection portion 14 a of the second solar cell 81. Are connected so that the small cross-sectional area portions 41 are disposed at all the locations of the first solar cell 80, the locations corresponding to the hollow portions 42a of the first solar cell 80, and the second unconnected portion 14a of the second solar cell 81. Even if it is formed in at least one of the locations corresponding to, the effect of reducing the warpage of the solar cell can be obtained. However, the small cross-sectional area 41 of the interconnector 31 is arranged as many as possible in locations corresponding to the hollow portion 42a of the first solar cell 80 and locations corresponding to the second non-connecting portion 14a of the second solar cell 81. Therefore, the interconnector 31 has a location corresponding to the hollow portion 42a of the first solar cell 80 and the second solar cell as described above. It is most preferable that the small cross-sectional area portions 41 are connected so as to be arranged at all the locations corresponding to the 81 second non-connecting portions 14a.

  In the solar cell string of the present invention, when at least one bus bar electrode 13a of the first solar cell 80 and the second solar cell 81 has a plurality of (for example, two or more) hollow portions 42a, It is preferable that the interval between the end portion of the first main surface of the p-type silicon substrate 10 as the semiconductor substrate and the hollow portion 42a adjacent to the end portion be narrower than the interval between the adjacent hollow portions 42a. In this case, since it is possible to form the small cross-sectional area portion 41 of the interconnector 31 at equal intervals, the processing of the interconnector 31 tends to be easy.

  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 bus bar electrode, the finger electrode, the first connection portion, and the second connection portion do not necessarily need to be silver electrodes, and the second non-connection portion does not need to be made of an aluminum electrode.

  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, while being able to reduce the curvature of a solar cell, a shadow loss is reduced, the solar cell with an interconnector which can improve the printability at the time of mass production, a solar cell string, and a solar cell module Can be provided.

It is a typical top view of a preferable example which shows the electrode shape of the light-receiving surface of the solar cell of this invention. It is a typical enlarged plan view of the electrode shape of the light-receiving surface of the solar cell shown in FIG. It is a typical top view of a preferable example which shows the electrode shape of the back surface of the solar cell shown in FIG. It is a typical top view of a desirable example of an interconnector for connecting to a solar cell of the present invention. It is typical sectional drawing of a preferable example of the solar cell string of this invention. It is a typical top view when the solar cell string of this invention shown in FIG. 5 is seen from the light-receiving surface side. It is a typical enlarged plan view of the vicinity of the 1st non-connecting part of the solar cell string of this invention shown in FIG. 5 and FIG. It is typical sectional drawing of an example of the conventional solar cell. It is a schematic diagram illustrating an example of the manufacturing method of the conventional solar cell. It is a schematic diagram illustrating an example of the manufacturing method of the conventional solar cell module. It is a typical top view which shows an example of the electrode shape of the light-receiving surface of a solar cell. It is a typical top view which shows an example of the electrode shape of the back surface of a solar cell. 11 is a schematic cross-sectional view of an example of a solar cell string in which solar cells having the light receiving surface electrode shown in FIG. 11 and the back electrode shown in FIG. 12 are connected using the interconnector described in Patent Document 1. FIG. is there. It is a typical top 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, 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-connecting part, 42a Hollow part, 51 First connecting part, 80 A first solar cell, 81 a second solar cell.

Claims (11)

A bus bar electrode and a plurality of linear finger electrodes extending from the bus bar electrode are provided on the first main surface of the semiconductor substrate,
The bus bar electrode includes a band-shaped portion having a hollow portion,
A region where the hollow portion exists in the longitudinal direction of the bus bar electrode is a first non-connection portion that is not connected to an interconnector,
When a region other than the first non-connection portion in the longitudinal direction of the bus bar electrode is a first connection portion for connecting to the interconnector,
The solar cell in which the first connection portion and the first non-connection portion are alternately arranged in the longitudinal direction of the bus bar electrode.   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 formed. The solar cell according to claim 1, wherein:   The solar cell according to claim 2, wherein the first connection portion and the second connection portion are formed at positions that are symmetrical with each other with respect to the semiconductor substrate.   4. The solar cell according to claim 1, wherein the bus bar electrode has a plurality of the hollow portions, and the intervals between the adjacent hollow portions are equal.   A solar cell string in which a plurality of the solar cells according to claim 2 are connected, wherein in the adjacent solar cells, the first connection portion of the first solar cell and the first of the second solar cell. A solar cell string in which two connecting portions are connected to an interconnector.   The interconnector has a small cross-sectional area portion in which the cross-sectional area of the interconnector is locally reduced in at least one position corresponding to the first non-connecting portion and the location corresponding to the second non-connecting portion. The solar cell string according to claim 5, comprising:   The interconnector has a small cross-sectional area portion in which the cross-sectional area of the interconnector is locally reduced at all the locations corresponding to the first non-connecting portion and the location corresponding to the second non-connecting portion. The solar cell string according to claim 5, comprising:   The said interconnector has the small cross-sectional area part by which the cross-sectional area of the said interconnector was reduced locally at least in one place corresponding to the said hollow part, The sun of Claim 5 characterized by the above-mentioned. Battery string.   6. The sun according to claim 5, wherein the interconnector has a small cross-sectional area part in which the cross-sectional area of the interconnector is locally reduced at all of the parts corresponding to the hollow part. Battery string.   The bus bar electrode has a plurality of the hollow portions, and at least one interval among the intervals between the end portion of the first main surface and the hollow portion adjacent to the end portion of the first main surface is The solar cell string according to any one of claims 5 to 9, wherein the solar cell string is narrower than an interval between the adjacent hollow portions.   A solar cell module, wherein the solar cell string according to claim 5 is sealed with a sealing material.

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