JP4040659B2 - Solar cell, solar cell string, and solar cell module - Google Patents

Solar cell, solar cell string, and solar cell module Download PDF

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JP4040659B2
JP4040659B2 JP2006112232A JP2006112232A JP4040659B2 JP 4040659 B2 JP4040659 B2 JP 4040659B2 JP 2006112232 A JP2006112232 A JP 2006112232A JP 2006112232 A JP2006112232 A JP 2006112232A JP 4040659 B2 JP4040659 B2 JP 4040659B2
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solar cell
non
interconnector
connecting portion
portion
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JP2007287861A (en
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京太郎 中村
孝尚 倉橋
彰 宮澤
敏夫 木村
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シャープ株式会社
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy

Description

  The present invention includes a solar cell electrically connected to another solar cell via an interconnector, a solar cell string in which a plurality of solar cells are electrically connected, and a solar cell string enclosed by a sealing material The present invention relates to a solar cell module.

  Solar cells convert solar energy directly into electrical energy. Therefore, in recent years, in particular, from the viewpoint of global environmental problems, expectations for solar cells are rapidly increasing as next-generation energy sources. As a material for photoelectric conversion in the solar cell, various materials such as a compound semiconductor or an organic material are used. At present, silicon crystals are mainly used.

  Hereinafter, a conventional solar cell will be described with reference to FIGS. First, the structure of a conventional solar cell will be described with reference to FIG.

FIG. 13 is a schematic cross-sectional view of an example of a conventional solar cell. As shown in FIG. 13, in the conventional solar cell, the n + layer 11 is formed from the light receiving surface of the p-type silicon substrate 10 to a position at a predetermined depth. 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 respectively formed on the light receiving surface of the p-type silicon substrate 10. A p + layer 15 is formed from the back surface of the light receiving surface of the p-type silicon substrate 10 to a position at a predetermined depth. An aluminum electrode 14 and a silver electrode 16 are also formed on the back surface of the p-type silicon substrate 10.

  Next, an example of a conventional method for manufacturing a solar cell will be described with reference to FIGS. In a conventional method for manufacturing a solar cell, first, a p-type silicon crystal material is melted in a crucible. Thereafter, the silicon ingot is recrystallized. Next, as shown in FIG. 14, the silicon ingot 17 is cut into silicon blocks 18. Next, as shown in FIG. 15, the silicon block 18 is cut by a wire saw. Thereby, the p-type silicon substrate 10 is obtained. At this time, as shown in FIG. 16, a damage layer 19 is formed on the p-type silicon substrate 10.

  Next, the surface of the p-type silicon substrate 10 is etched by alkali or acid. Thereby, the damaged layer 19 is removed from the surface of the p-type silicon substrate 10. At this time, if the etching conditions are adjusted, minute irregularities (not shown) may be formed on the surface of the p-type silicon substrate 10. Due to the unevenness, the reflection amount of sunlight incident on the surface of the p-type silicon substrate 10 is reduced. As a result, the conversion efficiency of the solar cell is increased.

Next, a dopant liquid 20 containing a compound containing phosphorus is applied onto one main surface (hereinafter referred to as “first main surface”) of the p-type silicon substrate 10. Thereafter, the p-type silicon substrate 10 coated with the dopant solution 20 is heat-treated at a temperature of 800 ° C. to 950 ° C. for 5 to 30 minutes. Thereby, as shown in FIG. 17, phosphorus, which is an n-type dopant, diffuses into the first main surface of the p-type silicon substrate 10. As a result, n + layer 11 is formed on the first main surface of p-type silicon substrate 10 as shown in FIG. As a method for forming the n + layer 11, there is a method using vapor phase diffusion using P 2 O 5 or POCl 3 besides the method of applying the dopant liquid.

A glass layer is formed on the first main surface of the p-type silicon substrate 10 when phosphorus is diffused. The glass layer is removed by acid treatment. Thereafter, as shown in FIG. 19, antireflection film 12 is formed on the first main surface of p-type silicon substrate 10. As a method of forming the antireflection film 12, a method of forming a titanium oxide film using an atmospheric pressure CVD (Chemical Vapor deposition) method or a method of forming a silicon nitride film using a plasma CVD method is known. In addition, when phosphorus is diffused by a method of applying a dopant liquid, a dopant liquid containing a material for the antireflection film 12 in addition to phosphorus may be used. According to this, the n + layer 11 and the antireflection film 12 can be formed simultaneously. Further, the antireflection film 12 may be performed after the silver electrode is formed.

Next, as shown in FIG. 20, 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 p-type silicon substrate 10 2 p + layer 15 is formed on the main surface. The aluminum electrode 14 and the p + layer 15 are formed by the following method.

For example, first, an aluminum paste made of aluminum powder, glass frit, resin, and organic solvent is prepared. Next, an aluminum paste is printed on the back surface of the silicon substrate 10 by screen printing or the like. Thereafter, the p-type silicon substrate 10 is heat-treated. Thereby, aluminum is melted and alloyed with the surface layer portion of the p-type silicon substrate 10. At this time, the p + layer 15 is formed under the aluminum-silicon alloy layer. An aluminum electrode 14 is formed on the second main surface of p-type silicon substrate 10.

In addition, the difference in dopant concentration between the p-type silicon substrate 10 and the p + layer 15, a potential difference is generated (acts as a potential barrier) at the interface between the p-type silicon substrate 10 and the p + layer 15. This prevents photogenerated carriers from recombining near the second main surface of the p-type silicon substrate 10. As a result, both the short circuit current (Isc) and the open circuit voltage (Voc) of the solar cell increase.

  Thereafter, as shown in FIG. 21, silver electrode 16 is formed on the second main surface of p-type silicon substrate 10. In forming the silver electrode 16, for example, first, a silver paste made of silver powder, glass frit, resin and organic solvent is prepared. Next, a silver paste is printed on the p-type silicon substrate 10 by screen printing or the like. Thereafter, the p-type silicon substrate 10 is heat-treated. Thereby, the silver electrode 16 is obtained.

  Next, as shown in FIG. 22, silver electrode 13 is formed on the first main surface of p-type silicon substrate 10. At this time, it is desirable that the series resistance including the contact resistance between the silver electrode 13 and the p-type silicon substrate 10 is low and the formation area of the silver electrode 13 is small. This is because the amount of incident sunlight is prevented from decreasing. Therefore, the pattern design such as the line width, pitch, and thickness of the silver electrode 13 is important.

  As a method for forming the silver electrode 13, the following method can be considered. For example, first, a silver paste made of silver powder, glass frit, resin and organic solvent is prepared. Next, a silver paste is printed on the surface of the antireflection film 12 by screen printing or the like. Thereafter, the p-type silicon substrate 10 is heat-treated. Thereby, the silver paste penetrates the antireflection film 12 and comes into contact with the first main surface of the p-type silicon substrate 10. Such a method is called a fire-through method and is mainly used in a mass production line.

  Through the above manufacturing process, the solar cell having the structure shown in FIG. 13 is manufactured. The p-type silicon substrate 10 after the silver electrode 13 and the silver electrode 16 are formed is immersed in the molten solder bath. Thereby, solder can be coated on the surfaces of the silver electrode 13 and the silver electrode 16. This solder coating may be omitted. Further, the solar cell manufactured as described above is irradiated with simulated sunlight using a solar simulator. Thereby, the current-voltage (IV) characteristic of the solar cell is inspected.

  The plurality of solar cells manufactured as described above are connected in series by an interconnector. Thereby, a solar cell string is formed. Thereafter, the solar cell string is encapsulated by the sealing material. Thereby, the solar cell module is completed.

  23 to 27 are views for explaining an example of a conventional method for manufacturing a solar cell module. In the conventional method for manufacturing a solar cell module, first, as shown in FIG. 23, an interconnector 31 that is a conductive member is connected on a silver electrode 13 (not shown) on the first main surface of the solar cell 30. Is done.

  Next, as shown in FIG. 24, the solar cells 30 to which the interconnectors 31 are connected are arranged in a line. The other end of the interconnector 31 connected to the silver electrode 13 (not shown) on the first main surface of the solar cell 30 is the silver electrode 16 (not shown) on the second main surface of the other solar cell 30. Connected to. As a result, a solar cell string is formed.

  Next, as shown in FIG. 25, the solar cell strings are arranged, 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 strings are electrically conductive. They are connected in series using a wiring member 33 that is a conductive member. Thereby, the solar cell strings are connected to each other.

  Next, as shown in FIG. 26, a plurality of solar cell strings 34 connected in series are sandwiched between EVA (ethylene vinyl acetate) films 36 as sealing materials. Thereafter, the EVA film 36 is sandwiched between the glass plate 35 and the back film 37. Next, bubbles that have entered between the EVA films 36 are extracted by the decompression means. Thereafter, the EVA film 36 is heated. Thereby, the EVA film 36 is cured. As a result, the solar cell string 34 is sealed in EVA. Thereby, a solar cell module is completed.

  Thereafter, as shown in FIG. 27, 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. Moreover, simulated solar light is irradiated to said solar cell module using a solar simulator. Thereby, the current-voltage (IV) characteristic of the solar cell is measured.

  FIG. 28 shows a pattern of the silver electrode 13 formed on the first main surface of the p-type silicon substrate 10 which becomes the light receiving surface of the solar cell shown in FIG. Here, the silver electrode 13 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.

  FIG. 29 shows a pattern of the aluminum electrode 14 and the silver electrode 16 formed on the second main surface of the p-type silicon substrate 10 which is the back surface of the solar cell shown in FIG. As shown in FIG. 29, 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. Is formed. This is because the aluminum electrode 14 cannot be coated with solder, but the silver electrode 16 can be coated with solder.

FIG. 30 shows a schematic cross section of a solar cell string in which solar cells having the structure shown in FIG. 13 are connected in series. As shown in FIG. 30, the interconnector 31 is fixed to the bus bar electrode 13 a on the light receiving surface of the solar cell 30 with solder or the like. Further, the interconnector 31 is fixed to the silver electrode 16 on the back surface of another adjacent solar cell 30 with solder or the like. In FIG. 30, the description of the n + layer and the p + layer is omitted.

  As the above-described solar power generation system is rapidly spread, it is indispensable to reduce the manufacturing cost of the solar cell 30.

  In order to reduce the manufacturing cost of solar cells, it is very effective to increase the size and thickness of a silicon substrate as a semiconductor substrate. However, as the silicon substrate becomes larger and thinner, the following problems occur.

  In order to form the solar cell string 34, a heat treatment step is performed in which the bus bar electrode 13a on the light receiving surface of the solar cell 30 and the interconnector 31 made of copper are fixed with solder or the like. A subsequent cooling step is performed.

The thermal expansion coefficient of silicon is 3.5 × 10 −6 / K. On the other hand, the thermal expansion coefficient of copper is 17.6 × 10 −6 / K. Moreover, the thermal expansion coefficient of copper is about 5 times the thermal expansion coefficient of silicon. Therefore, due to the difference in thermal expansion coefficient between the p-type silicon substrate 10 of the solar cell 30 and the interconnector 31 made of copper, the interconnector 31 contracts more than the solar cell 30. As a result, the solar cell 30 is warped. Moreover, a crack occurs in the light receiving surface of the solar cell 30 that is in contact with the bus bar electrode 13 a of the solar cell 30.

  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 30 as a method for solving the above-described problem.

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 this time, a force (restoring force) for returning to the original shape is generated in the solar cell. This restoring force applies a tensile stress to the interconnector.
JP 2005-142282 A

  According to the method disclosed in Patent Document 1, when a tensile stress is applied to the interconnector, a small cross-sectional area portion having a relatively small strength as compared with other portions is extended. Thereby, the curvature of a solar cell is suppressed to some extent. However, a method that does not cause any warpage of the solar cell is desired.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a solar cell, a solar cell string, and a solar cell module that do not warp.

  In addition, as an undisclosed technique, the inventors of the present application form an electrode on a semiconductor substrate having a connection portion that is in contact with the interconnector and a non-connection portion that is not in contact with the interconnector, and is not connected We are studying to absorb the stress generated in the interconnector. However, the non-connection portion functions as a resistor and is a useless portion as an electrode material. Accordingly, a further object of the present invention is to provide a solar cell, a solar cell string, and a solar cell module that do not warp while reducing the resistance of the electrode material and reducing waste of the electrode material.

The solar cell of the present invention comprises a semiconductor substrate having a photoelectric conversion portion in the vicinity of the main surface, one electrode extending linearly on the main surface, and another electrode connected to the one electrode on the main surface. I have. One electrode includes a plurality of connecting portions which can be electrically connected via the interconnector to another solar cell, but to connect the connection part between the non-connected that extends linearly so as not to contact the interconnector Includes with parts. Further, the non-connecting portion bypasses the gap disposed between the connecting portions connected by the non-connecting portion and connects the connecting portions to each other, and the connection portion extends and the non-connecting portion extends. The angle is greater than 90 ° and less than 180 °.

  According to said structure, the solar cell which does not produce curvature is obtained. Moreover, according to said structure, compared with the solar cell whose angle which the direction which a connection part extends and the direction which a connection part makes is 90 degrees, a connection part becomes short. Therefore, the series resistance of the non-connection portion is reduced. Moreover, shadow loss is reduced, that is, the amount of electrode material used is reduced.

  The solar cell of the present invention is provided on the other main surface on the back side of the main surface of the semiconductor substrate, and a plurality of other connection portions that can be connected to another interconnector different from the interconnector, and on the other main surface And at least one other non-connection portion that is provided between the other connection portions and extends linearly so as not to contact the interconnector.

  In addition, the connection part and the other connection part may be arranged mirror-symmetrically with respect to the semiconductor substrate.

  Further, the non-connecting portion may extend from the end face of the connecting portion. Moreover, the non-connection part may extend from the side surface of the connection part. Moreover, the non-connection part may consist of the combination of a linear part. Moreover, the non-connecting part may include an arcuate part. Moreover, it is desirable that the width of the non-connection portion is less than ½ of the width of the connection portion.

  Further, at least one of the connection portions adjacent to the end portion of the main surface may be installed away from the end portion of the main surface.

  The solar cell string of the present invention includes a plurality of solar cells. Each of the plurality of solar cells is the above-described solar cell of the present invention. In the solar cell string of the present invention, the aforementioned plurality of solar cells are connected in series. Moreover, in the relationship between solar cells adjacent to each other, a connection portion of one solar cell and another connection portion of the other solar cell are electrically connected via an interconnector.

The interconnector may be bent between the solar cells.
Further, the cross-sectional area of the interconnector is locally reduced to at least one of a position facing at least one non-connecting portion and a position facing at least one other non-connecting portion. It is desirable to have a small cross-sectional area.

  Moreover, it is desirable that the interconnector has a portion having a locally small cross-sectional area at all positions including a position facing at least one non-connecting portion and a position corresponding to at least another non-connecting portion.

  In the solar cell module of the present invention, the above-described solar cell string is constituted by a sealing material.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the curvature of the solar cell which arises when forming a solar cell string can be suppressed.

  In order to solve the above-mentioned problems, the inventors of the present application have developed a solar cell as shown in FIG. 31 and FIG. As shown in FIGS. 31 and 32, the solar cell includes a linear electrode 13a formed on the first main surface of the silicon substrate and a plurality of linear finger electrodes 13b extending from the bus bar electrode 13a. And. In addition, the bus bar electrode 13a includes a first connection portion 51 that can be connected to the interconnector 31, a straight line that extends without being connected to the interconnector 31 and that extends parallel to the side of the first connection portion 51, and the first connection. 1st non-connecting part 42 extended along each of the straight line extended perpendicularly to the side of part 51. Moreover, the 1st connection part 51 and the non-connection part 42 are arranged by turns. The first unconnected portion 42 is not connected to the interconnector 31. Therefore, the deformation of the interconnector 31 is not constrained at the portion corresponding to the first non-connecting portion 42. Therefore, even if the interconnector 31 expands in the linear direction, the linear expansion is absorbed by the portion corresponding to the first non-connecting portion 42. Therefore, warpage of the p-type silicon substrate 10 is prevented.

  In the above solar cell, as shown in FIGS. 31 and 32, the first non-connecting portion 42 is not connected to the interconnector 31 when the first connecting portion 51 is connected to the interconnector 31. That is, the interconnector 31 and the first non-connecting portion 42 do not overlap in plan view. For this reason, when the first non-connecting portion 42 becomes thick, there arises a problem of an increase in generation of unnecessary electrode material, that is, an increase in shadow loss. In addition, the current collected by the finger electrode 13 b connected to the first non-connecting portion 42 reaches the interconnector 31 from the first connecting portion 51 via the first non-connecting portion 42. Therefore, if the first non-connection portion 42 becomes thin, there arises a problem that the series resistance of the first non-connection portion 42 increases.

  In this case, if the width of the first non-connection portion 42 is reduced in order to reduce the shadow loss, the series resistance of the first non-connection portion 42 is increased. Conversely, when the width of the first non-connecting portion 42 is increased in order to reduce the series resistance, the shadow loss increases. That is, the increase in shadow loss and the increase in series resistance have a trade-off relationship. Therefore, it is difficult to solve these problems at the same time.

  Therefore, in the solar cell of the embodiment shown below, both the above-described problem of increase in the shadow loss of the non-connection portion and the problem of increase in series resistance are solved.

  Hereinafter, a solar cell according to an embodiment of the present invention will be described with reference to the drawings. In the drawings of the present specification, parts denoted by the same reference numerals are the same parts or parts corresponding to the parts. Of the matters described above, matters not described in the embodiments described below are also applicable to the following embodiments unless the object of the present invention is impaired. And 2 and 6 to 10, the interconnector 31 is drawn with a broken line because it is not actually connected to the bus bar electrode 13a.

  FIG. 1 is a schematic plan view of an example of the light receiving surface of the solar cell of the embodiment. In the solar cell of the present embodiment, the light receiving surface is the first main surface of p-type silicon substrate 10 as in the prior art. On the first main surface, a relatively wide linear bus bar electrode 13a extending in the left-right direction of the paper surface is provided. The bus bar electrode 13a is an example of the first electrode of the present invention. On the first main surface, a plurality of relatively narrow linear finger electrodes 13b extending from the bus bar electrode 13a in the vertical direction of the drawing are provided. The finger electrode 13b is an example of another electrode of the present invention. Moreover, although the bus-bar electrode 13a and the finger electrode 13b are orthogonal, those positional relationships can be changed according to the form of a solar cell.

  The bus bar electrode 13 a includes a linear first connection portion 51 that is fixed to and electrically connected to the interconnector 31. The bus bar electrode 13 a includes two first non-connecting portions 42 that extend in the same direction via a gap that is not electrically connected to the interconnector 31. The first connection parts 51 and the first non-connection parts 42 are alternately arranged. Specifically, as shown in FIG. 1, three first connection portions 51 are formed for one bus bar electrode 13a. In addition, one first non-connection portion 42 is formed between the adjacent first connection portions 51.

  FIG. 2 is a schematic enlarged plan view of the first unconnected portion 42 shown in FIG. 1 and the structure in the vicinity thereof. In the present embodiment, as shown in FIG. 2, the first non-connecting portion 42 forms an angle of about 150 ° with respect to the direction in which the side 51 a of the first connecting portion 51 extends. 51 extends from the side 51a. This angle may be any value as long as it is larger than 90 ° and smaller than 180 °. Further, the first non-connecting portion 41 is composed of two linear members that connect the side edges 51 a of the first connecting portion 51. Each of the two linear members includes a plurality of (for example, three) straight portions.

  FIG. 3 is a schematic plan view of an example of the back surface of the solar cell shown in FIG. In the solar cell of the present embodiment, the back surface of the light receiving surface is the second main surface of p-type silicon substrate 10 as in the prior art. On the 2nd main surface, the silver electrode 16 as a 2nd connection part electrically connected to the interconnector 31 is provided. A second non-connection portion that is not electrically connected to the interconnector 31 is provided on the second main surface. Moreover, the silver electrode 16 as a 2nd connection part and the aluminum electrode 14 as a 2nd non-connection part are alternately arrange | positioned on the 2nd main surface.

  In the present embodiment, the aluminum electrode 14 as the second non-connection portion is provided so as to surround each of the silver electrodes 16 as the second connection portion. The second connection part (silver electrode 16) and the first connection part 51 are arranged mirror-symmetrically with respect to the p-type silicon substrate 10.

  FIG. 4 is 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. 1 and the back surface shown in FIG. 3 are connected in series. FIG. 5 is a schematic enlarged plan view when the solar cell string shown in FIG. 4 is viewed from the light receiving surface side. In the present embodiment, one of the solar cells adjacent to each other, the first connecting portion 51 of one solar cell and the silver electrode 16 that is the second connecting portion of the other solar cell are electrically connected by solder or the like. It is fixed and electrically connected to an interconnector 31 made of a member.

Moreover, neither the aluminum electrode 14 used as the 1st non-connecting part 42 of a solar cell nor the 2nd non-connecting part is being fixed to the interconnector 31, and is not electrically connected. In addition, the interconnector 31 is bent in the edge part of a solar cell between solar cells. In FIG. 4, the drawing of the n + layer and the p + layer is omitted.

  In the solar cell string of the present embodiment, each of the two first non-connection portions 42 of the solar cell is shorter than the solar cell string shown in FIGS. 31 and 32.

  The current flowing through the finger electrode 13b shown in FIG. 2 flows through the first non-connecting portion 42 until reaching the first connecting portion 51 of the bus bar electrode 13a. This shortest distance is 2.9 mm. On the other hand, the current flowing through the finger electrode 13b shown in FIG. 32 also flows through the first non-connection portion 42 until reaching the first connection portion 51 of the bus bar electrode 13a. This shortest distance is 4.0 mm.

  Due to this difference in length, a difference occurs in the resistance value of the first non-connecting portion 42. Therefore, the solar cell shown in FIG. 2 of the present embodiment has better characteristics than the solar cells shown in FIG. 31 and FIG.

  Further, as described above, the first non-connecting portion 42 is a portion that does not overlap the interconnector 31, and is therefore a shadow loss portion. Therefore, if the line width is the same, the first non-connecting portion 42 shown in FIG. 1 of the present embodiment is approximately less than the first non-connecting portion 42 shown in FIGS. 31 and 32. 20% shadow loss can be reduced.

  Further, the shortening of the first non-connecting portion 42 reduces the possibility that the first non-connecting portion 42 may be blurred when the first non-connecting portion 42 is printed on the p-type silicon substrate 10. . Therefore, the resistance value from the finger electrode 13b connected to the first non-connecting portion 42 to the first connecting portion 51 of the bus bar electrode 13a is further reduced. As a result, the yield of solar cells can be improved.

  Further, in the present embodiment, the shape of the first non-connecting portion 42 is not limited to the shape shown in FIGS. 1 and 2, and may be the shape shown in FIG. 6, for example. In FIG. 6, the first non-connecting portion 42 extends from the side of the first connecting portion 51 at an angle of about 135 ° with respect to the side 51 a of the first connecting portion 51.

  In the present invention, the shape of the first non-connecting portion 42 is not limited to the shape shown in FIGS. 1 and 2, and may be the shape shown in FIG. 7, for example. In FIG. 7, the first non-connecting portion 42 extends from the side surface of the first connecting portion 51. According to this, even when the width of the interconnector 31 and the width of the bus bar electrode 13a are substantially equal, the angle formed by the interconnector 31 and the bus bar electrode 51 at the intersection of the interconnector 31 and the bus bar electrode 51 is reduced to about It can be reduced to about 30 °.

  If the first non-connecting portion 41 as described above is provided, the stress generated in the p-type silicon substrate 10 due to the difference between the thermal expansion coefficient of the interconnector 31 and the thermal expansion coefficient of the silicon substrate 10 is reduced. The That is, since the first non-connecting portion 41 is not restrained by the interconnector 31, the first unconnected portion 41 is freely deformed even if thermal expansion occurs, and absorbs the entire linear expansion of the interconnector 31. As a result, the risk of wafer cracking is reduced.

  Further, when the interconnector 31 is narrower than the bus bar electrode 13a, even if the first non-connecting portion 42 extends from the end face of the first connecting portion 51, the same effect as described above can be obtained. When the interconnector 31 is wider than the bus bar electrode 13a, the bus bar electrode having the shape shown in FIG. 1 can be obtained if the first non-connecting portion 42 extends from the side surface 51a of the first connecting portion 51. The same effect as that obtained by 13a can be obtained. The first non-connecting portion 42 used in the present invention may have any other shape as long as the object of the invention can be achieved.

  Moreover, in the solar cell of this invention, the shape of the 1st non-connecting part 42 may be a shape containing an arc-shaped part, as FIG. 8 or FIG. 9 shows. Note that, according to the shape shown in FIG. 9, the non-connecting portion 42 extends from the end surface of the first connecting portion 51.

  By adopting these shapes, the angle formed by the bus bar electrode 13a and the interconnector 31 at the intersection between the bus bar electrode 13a and the interconnector 31 is reduced. As a result, the length of the first unconnected portion 41 can be shortened.

  When the width of the interconnector 31 is larger than the width of the bus bar electrode 13a, the shape shown in FIG. 8 is adopted, and when the width of the interconnector 13 is smaller than the width of the bus bar electrode 13a, FIG. It is desirable to adopt the shape shown in FIG.

  Moreover, in the solar cell of this invention, the shape of the bus-bar electrode 13a of the 1st non-connection part 42 is the width | variety of the bus-bar electrode 13a of the 1st non-connection part 42 shown by FIG. May have different widths. As the width of the bus bar electrode 13a of the first non-connecting portion 42 is smaller, the series resistance value is increased, but the amount of electrode material used is reduced. Conversely, the larger the cross-sectional area of the first non-connecting portion 42, the more the electrode material is used, but the series resistance value is reduced. However, when compared with the case where the first non-connecting portion 42 is not provided, the shadow loss increases when the cross-sectional area of the first non-connecting portion 42 is larger than ½ of the cross-sectional area of the first connecting portion 51, that is, the electrode. There is almost no merit in reducing the series resistance value only by increasing the amount of material used. Therefore, it is desirable that the maximum cross-sectional area of the first non-connecting portion 42 is ½ or less of the maximum cross-sectional area of the first connecting portion 51.

  11 is a schematic enlarged plan view of a state where an interconnector having a shape different from the shape shown in FIG. 5 is connected. Here, the notch is formed in the interconnector 31 shown in FIG. Thereby, the cross-sectional area of the interconnector 31 has a small cross-sectional area 41 that is locally small.

  In the present invention, the “small cross-sectional area portion” refers to a portion of the interconnector 31 where the cross-sectional area perpendicular to the longitudinal direction of the interconnector 31 is locally reduced. Further, in a state where the interconnector 31 is connected, the small cross-sectional area portion 41 is disposed so as to correspond to the first non-connecting portion 42.

  FIG. 12 is a schematic cross-sectional view of an example of a solar cell string configured using the interconnector 31 shown in FIG. Here, the small cross-sectional area portions 41 of the interconnector 31 are disposed at all locations corresponding to the first non-connecting portion 42 and at all locations corresponding to the aluminum electrode 14 that is the second non-connecting portion.

As shown in FIG. 12, the interconnector 31 is also bent between the solar cells. In FIG. 12, drawing of the n + layer and the p + layer is omitted.

  As described above, in the present embodiment, using the interconnector 31 having the small cross-sectional area 41, the small cross-sectional area 41 corresponds to the first non-connecting portion 42 and the second non-connecting portion (aluminum electrode). A solar cell string to which the interconnector 31 is connected may be formed so as to be arranged at least at one of the locations corresponding to 14), preferably at all locations. In this case, in addition to the effect of reducing the warpage of the solar cell described above, the small cross-sectional area 41 having a lower strength than the other parts of the interconnector 31 is extended, and the stress generated in the interconnector 31 is reduced. Is done. Thereby, the curvature of a solar cell is reduced.

  That is, when the small cross-sectional area 41 of the interconnector 31 is arranged in the first non-connecting part 42 and the second non-connecting part (aluminum electrode), the small cross-sectional area 41 is not fixed and is in a free state. It has become. Therefore, the small cross-sectional area 41 can be freely deformed. As a result, in the solar cell of the present embodiment, the stress generated in the silicon substrate 10 or the like due to the extension of the interconnector 31 is reduced. Therefore, in this case, warpage occurring in the solar cells constituting the solar cell string is greatly reduced. As a result, it becomes possible to significantly reduce the occurrence of cracks in the solar cells that constitute the solar cell string.

  In the solar cell of the present invention, the interconnector 31 having the shape shown in FIG. 11 may be used.

  Such a solar cell string of the present embodiment is sealed with a sealing material such as EVA by a conventionally known method. Thereby, the solar cell module of the present embodiment is completed.

  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 conductivity types of the p-type and the n-type described in the background art section may be exchanged.

  Moreover, in the solar cell of this invention, a 1st connection part and a 2nd connection part are not limited to a silver electrode, The electrode containing another electroconductive substance may be sufficient. The first non-connecting portion is not limited to the gap and may be a portion including a substance having low conductivity. Further, the second non-connecting portion is not limited to the aluminum electrode, and may be a portion including a substance having low conductivity.

  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 which can reduce generation | occurrence | production of the crack of the solar cell which comprises a solar cell string, a solar cell string, and a solar cell module can be provided.

It is a typical top view of an example of the light-receiving surface of the solar cell of embodiment. It is a typical enlarged plan view of the 1st non-connecting part of the solar cell of an embodiment. FIG. 2 is a schematic plan view of an example of the back surface of the solar cell shown in FIG. 1. FIG. 4 is a schematic cross-sectional view of an example of a solar cell string in which solar cells having the light receiving surface shown in FIGS. 1 and 2 and the back surface shown in FIG. 3 are connected in series. It is a typical enlarged plan view when the solar cell string shown in FIG. 4 is seen from the light receiving surface side. It is a typical top view of other examples of the 1st non-connection part of an embodiment. It is a typical top view of other examples of the 1st non-connection part of an embodiment. It is a typical top view of other examples of the 1st non-connection part of an embodiment. It is a typical top view of other examples of the 1st non-connection part of an embodiment. It is a typical top view of other examples of the 1st non-connection part of an embodiment. It is a typical top view of an example of the structure of the 1st non-connection part to which the interconnector was connected. It is typical sectional drawing of an example of the solar cell string comprised using the interconnector shown by FIG. It is typical sectional drawing of an example of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell. It is a figure for demonstrating the manufacturing method of the conventional solar cell module. It is a figure for demonstrating the manufacturing method of the conventional solar cell module. It is a figure for demonstrating the manufacturing method of the conventional solar cell module. It is a figure for demonstrating the manufacturing method of the conventional solar cell module. It is a figure for demonstrating the manufacturing method of the conventional solar cell module. It is a figure which shows the pattern of the silver electrode formed on the 1st main surface of the p-type silicon substrate used as the light-receiving surface of the solar cell shown by FIG. It is a figure which shows the pattern of the aluminum electrode and silver electrode which were formed on the 2nd main surface of the p-type silicon substrate used as the back surface of the solar cell shown by FIG. It is typical sectional drawing of the solar cell string which connected the solar cell shown by FIG. 13 in series. It is a typical top view of an example of the light-receiving surface of the solar cell which the inventors of this application developed previously as an undisclosed technique. FIG. 32 is a schematic enlarged plan view of the vicinity of a first non-connection portion shown in FIG. 31.

Explanation of symbols

10 p-type silicon substrate, 11 n + layer, 12 antireflection film, 13, 16 silver electrode, 1
3a bus bar electrode, 13b finger electrode, 14 aluminum electrode, 15 p + layer, 17 silicon ingot, 18 silicon block, 20 dopant liquid, 30 solar cell, 31 interconnector, 33 wiring material, 34 solar cell string, 35 glass plate, 36 EVA film, 37 back film, 38 terminal box, 39 cable, 40 aluminum frame, 41 small cross-sectional area portion, 42 first non-connection portion, 51 first connection portion.

Claims (14)

  1. A semiconductor substrate having a photoelectric conversion portion in the vicinity of the main surface;
    One electrode extending linearly on the main surface;
    Another electrode connected to the one electrode on the main surface,
    The one electrode is
    A plurality of connections that can be electrically connected to other solar cells via an interconnector;
    Connecting the front Kise' connection part between, but includes a non-connecting portion said that extends linearly so as not to contact the interconnector,
    The non-connecting portion connects the connecting portions by bypassing a gap disposed between the connecting portions to which the non-connecting portion is connected,
    A solar cell, wherein an angle formed between a direction in which the connection portion extends and a direction in which the non-connection portion extends is greater than 90 ° and less than 180 °.
  2. A plurality of other connecting portions provided on the other main surface on the back side of the main surface of the semiconductor substrate, which can be connected to another interconnector different from the interconnector;
    The apparatus further comprises at least one other non-connection portion provided between the plurality of other connection portions on the other main surface and extending linearly so as not to contact the interconnector. 1. The solar cell according to 1.
  3.   The solar cell according to claim 2, wherein the connection part and the other connection part are arranged in mirror symmetry with respect to the semiconductor substrate.
  4.   The solar cell according to claim 1, wherein the non-connecting portion extends from an end surface of the connecting portion.
  5.   The solar cell according to claim 1, wherein the non-connection portion extends from a side surface of the connection portion.
  6.   The solar cell according to any one of claims 1 to 5, wherein the non-connecting portion includes a combination of straight portions.
  7.   The solar cell according to claim 1, wherein the non-connecting portion includes an arc-shaped portion.
  8.   The solar cell in any one of Claims 1-7 whose cross-sectional area of the said non-connection part is less than 1/2 of the cross-sectional area of the said connection part.
  9.   The solar cell according to any one of claims 1 to 8, wherein at least one of the connection portions adjacent to an end portion of the main surface is disposed apart from an end portion of the main surface.
  10. With multiple solar cells,
    Each of the plurality of solar cells is a solar cell according to any one of claims 1 to 9,
    A solar cell string in which the plurality of solar cells are connected in series,
    In the relationship between the solar cells adjacent to each other, the solar cell in which the connecting portion of one of the solar cells and the other connecting portion of the other solar cell are electrically connected via the interconnector. string.
  11.   The solar cell string according to claim 10, wherein the interconnector is bent between the solar cells.
  12. The interconnector has a portion having a locally small cross-sectional area at at least one of a position facing the non-connecting portion and a position facing the other non-connecting portion. The solar cell string as described.
  13.   The interconnector has a portion having a locally small cross-sectional area at all positions of the position facing the at least one unconnected portion and the position facing the at least one other unconnected portion. Or the solar cell string of 11.
  14.   The solar cell module in which the solar cell string in any one of Claims 10-13 was included by the sealing material.
JP2006112232A 2006-04-14 2006-04-14 Solar cell, solar cell string, and solar cell module Active JP4040659B2 (en)

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JP2006112232A JP4040659B2 (en) 2006-04-14 2006-04-14 Solar cell, solar cell string, and solar cell module
PCT/JP2007/055171 WO2007119365A1 (en) 2006-04-14 2007-03-15 Solar cell, solar cell string and solar cell module
EP07738621A EP2012362A1 (en) 2006-04-14 2007-03-15 Solar cell, solar cell string and solar cell module
US12/296,748 US8440907B2 (en) 2006-04-14 2007-03-15 Solar cell, solar cell string and solar cell module
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JP4174545B1 (en) * 2007-05-10 2008-11-05 シャープ株式会社 Solar cell, solar cell manufacturing method, solar cell string and solar cell module
KR101195624B1 (en) * 2008-03-31 2012-10-30 샤프 가부시키가이샤 Solar cell, solar cell string and solar cell module
WO2010007946A1 (en) * 2008-07-16 2010-01-21 三菱電機株式会社 Interconnector
JP2010239167A (en) * 2010-07-30 2010-10-21 Sanyo Electric Co Ltd Solar cell module
JP5857237B2 (en) * 2010-11-29 2016-02-10 パナソニックIpマネジメント株式会社 Solar cell and solar cell module
JP5014502B2 (en) * 2011-06-20 2012-08-29 三洋電機株式会社 Method for manufacturing solar cell and method for manufacturing solar cell module
JP5014503B2 (en) * 2011-06-20 2012-08-29 三洋電機株式会社 Solar cell and solar cell module
JP5306423B2 (en) * 2011-07-19 2013-10-02 三菱電機株式会社 Solar cells
CN103797583B (en) * 2011-09-13 2015-07-15 京瓷株式会社 Solar cell module
JP5857245B2 (en) * 2011-09-29 2016-02-10 パナソニックIpマネジメント株式会社 Solar cell, solar cell module and manufacturing method thereof
JP5820278B2 (en) * 2012-01-10 2015-11-24 シャープ株式会社 Solar cell and method for manufacturing solar cell
EP3125300B1 (en) * 2014-03-27 2018-12-12 KYOCERA Corporation Solar cell and solar cell module using same
KR101861172B1 (en) * 2014-07-09 2018-05-28 엘지전자 주식회사 Solar cell
JP6573151B2 (en) * 2014-09-29 2019-09-11 パナソニックIpマネジメント株式会社 Manufacturing method of solar cell
JP2018137250A (en) * 2015-06-30 2018-08-30 パナソニックIpマネジメント株式会社 Solar cell module
JP2015188117A (en) * 2015-07-29 2015-10-29 パナソニックIpマネジメント株式会社 solar cell
KR101778128B1 (en) * 2016-01-20 2017-09-13 엘지전자 주식회사 Solar cell
WO2018235202A1 (en) * 2017-06-21 2018-12-27 三菱電機株式会社 Solar battery cell and solar battery module

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