WO2012090641A1 - Solar cell - Google Patents

Solar cell Download PDF

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Publication number
WO2012090641A1
WO2012090641A1 PCT/JP2011/077769 JP2011077769W WO2012090641A1 WO 2012090641 A1 WO2012090641 A1 WO 2012090641A1 JP 2011077769 W JP2011077769 W JP 2011077769W WO 2012090641 A1 WO2012090641 A1 WO 2012090641A1
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Prior art keywords
conductivity type
conductivity
finger electrode
type
solar cell
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PCT/JP2011/077769
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French (fr)
Japanese (ja)
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有二 菱田
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三洋電機株式会社
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Publication of WO2012090641A1 publication Critical patent/WO2012090641A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H01L31/022441—Electrode arrangements specially adapted for back-contact solar cells
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/547—Monocrystalline silicon PV cells

Definitions

  • the present invention relates to a back junction solar cell.
  • Patent Document 1 describes a solar cell in which comb-shaped p-side electrodes and n-side electrodes that are interleaved with each other are formed on the back surface as a back surface junction type solar cell.
  • this back junction solar cell it is not necessary to provide an electrode on the light receiving surface side. For this reason, in the back junction solar cell, the light receiving efficiency can be increased. Therefore, higher photoelectric conversion efficiency can be realized.
  • the present invention has been made in view of such a point, and an object thereof is to provide a solar cell having improved photoelectric conversion efficiency.
  • the solar cell according to the present invention includes a solar cell substrate, one conductivity type side electrode, and another conductivity type side electrode.
  • the solar cell substrate has one conductivity type surface and another conductivity type surface on one main surface.
  • the one conductivity type side electrode is arranged on the one conductivity type surface.
  • the other conductivity type side electrode is disposed on the other conductivity type surface.
  • the other conductivity type side electrode has a plurality of other conductivity type side finger electrode portions and another conductivity type side bus bar portions. Each of the plurality of other conductivity type finger electrode portions extends from one side in the first direction toward the other side.
  • the plurality of other conductivity type finger electrode portions are arranged along a second direction perpendicular to the first direction.
  • the other conductivity type side bus bar portion electrically connects a plurality of other conductivity type side finger electrode portions.
  • the one conductivity type side electrode has a plurality of comb-like electrode portions.
  • the plurality of comb-like electrode portions are arranged along the second direction.
  • Each of the plurality of comb-like electrode portions has a plurality of one-conductivity-type finger electrode portions and a one-conductivity-type busbar portion.
  • Each of the plurality of one-conductivity-type finger electrode portions extends from the other side in the first direction toward one side between the other-conductivity-type finger electrode portions adjacent in the second direction.
  • the one conductivity type side bus bar portion electrically connects a plurality of one conductivity type side finger electrode portions.
  • the plurality of other-conductivity-type finger electrode portions include other-conductivity-type finger electrode portions located between the comb-shaped electrode portions adjacent in the second direction.
  • the front end portion of the other conductivity type finger electrode portion located between the adjacent comb-shaped electrode portions is positioned between the one conductivity-type bus bar portions of the adjacent comb-shaped electrode portions.
  • a solar cell having improved photoelectric conversion efficiency can be provided.
  • FIG. 1 is a schematic plan view of the solar cell according to the first embodiment.
  • FIG. 2 is a schematic plan view of the solar cell according to the second embodiment.
  • FIG. 3 is a schematic plan view of a solar cell according to the third embodiment.
  • FIG. 4 is a schematic plan view of a solar cell according to the fourth embodiment.
  • FIG. 5 is a schematic plan view of a solar cell according to the fifth embodiment.
  • FIG. 6 is a schematic plan view in which a part of the solar cell according to the fifth embodiment is enlarged.
  • FIG. 7 is a schematic plan view in which a part of the solar cell according to the first embodiment is enlarged.
  • FIG. 1 is a schematic plan view of the back surface of the solar cell 1 of the present embodiment.
  • FIG. 1 and FIGS. 2 to 7 described below hatching is provided for easy understanding of the shape of the electrode, but the hatched region in FIGS. 1 to 7 is not a cross section.
  • the solar cell 1 is a so-called back junction type solar cell.
  • the solar cell 1 has a solar cell substrate 10.
  • the solar cell substrate 10 is a member that generates carriers such as electrons and holes by receiving light.
  • Solar cell substrate 10 has a light receiving surface and a back surface 10a. The n-type surface 10an and the p-type surface 10ap are exposed on the back surface 10a.
  • the solar cell substrate 10 includes a substrate made of a crystalline semiconductor having one conductivity type, and a p-type amorphous semiconductor layer and an n-type amorphous semiconductor layer disposed on the back surface of the semiconductor substrate. There may be.
  • the p-type surface 10ap is constituted by the surface of the p-type amorphous semiconductor layer.
  • the n-type surface 10an is constituted by the surface of the n-type amorphous semiconductor layer.
  • the p-type amorphous semiconductor layer can be formed of, for example, p-type amorphous silicon containing hydrogen.
  • the n-type amorphous semiconductor layer can be formed of, for example, n-type amorphous silicon containing hydrogen.
  • An i-type amorphous semiconductor layer having a thickness that does not substantially contribute to power generation is disposed between each of the p-type amorphous semiconductor layer and the n-type amorphous semiconductor layer and the crystalline semiconductor layer. May be.
  • the i-type amorphous semiconductor layer can be formed of, for example, i-type amorphous silicon containing hydrogen.
  • the solar cell substrate 10 has one conductivity type, and a semiconductor substrate in which a p-type dopant diffusion region in which a p-type dopant is diffused and an n-type dopant diffusion region in which an n-type dopant is diffused is provided on the back surface side. It may be configured.
  • the p-type surface 10ap is constituted by the surface of the p-type dopant diffusion region.
  • the n-type surface 10an is constituted by the surface of the n-type dopant diffusion region.
  • the thickness of the semiconductor substrate is preferably 2 mm or less.
  • the lower limit of the thickness of the semiconductor substrate is preferably 0.01 mm.
  • the specific resistance of the crystalline semiconductor substrate is preferably 0.1 ⁇ cm to 100 ⁇ cm.
  • the solar cell substrate 10 includes an n-type semiconductor substrate, and a p-type amorphous semiconductor layer and an n-type amorphous semiconductor layer disposed on the back surface of the semiconductor substrate.
  • n-type semiconductor substrate a p-type amorphous semiconductor layer and an n-type amorphous semiconductor layer disposed on the back surface of the semiconductor substrate.
  • one conductivity type is n-type, and holes become minority carriers.
  • a p-side electrode 11p and an n-side electrode 11n are disposed on the back surface 10a of the solar cell substrate 10.
  • the p-side electrode 11p is disposed on the p-type surface 10ap.
  • the n-side electrode 11n is disposed on the n-type surface 10an.
  • the material of the p-side electrode 11p and the n-side electrode 11n is not particularly limited as long as it is a conductive material.
  • Each of the p-side electrode 11p and the n-side electrode 11n includes, for example, a metal such as silver, copper, aluminum, titanium, nickel, or chromium, an alloy containing one or more of these metals, TCO (Transparent Conductive Oxide), and the like. Can be formed.
  • each of the p-side electrode 11p and the n-side electrode 11n may be configured by a stacked body of a plurality of conductive layers made of, for example, the above metal, alloy, or TCO.
  • Each of the p-side electrode 11p and the n-side electrode 11n can be formed using, for example, a sputtering method, a vapor deposition method, a screen printing method, a plating method, or the like.
  • the p-side electrode 11p is composed of one comb-like electrode.
  • the p-side electrode 11p may be composed of a plurality of comb-like electrodes.
  • the p-side electrode 11p has a plurality of finger electrode portions 12p as p-side finger electrode portions and a bus bar portion 13p as a p-side bus bar portion.
  • Each of the plurality of finger electrode portions 12p extends linearly from the x2 side in the x direction toward the x1 side.
  • the plurality of finger electrode portions 12p are arranged along the y direction perpendicular to the x direction.
  • the plurality of finger electrode portions 12p are electrically connected by the bus bar portion 13p.
  • the bus bar portion 13p is disposed on the x2 side of the plurality of finger electrode portions 12p.
  • the bus bar portion 13p is formed in a linear shape.
  • the shape of the p-side bus bar portion is not particularly limited as long as a plurality of p-side finger electrode portions are electrically connected.
  • the p-side bus bar portion may not be linear.
  • the p-side bus bar portion may include an electrode pad and a plurality of connection portions that connect the electrode pad and the p-side finger electrode portion.
  • the n-side electrode 11n is separated into a plurality of electrode portions. Specifically, the n-side electrode 11n has a plurality of comb-like electrode portions 14. The number of comb-like electrode portions 14 included in the n-side electrode 11n is preferably 2 to 50, and more preferably 3 to 5.
  • the plurality of comb-like electrode portions 14 are arranged along the y direction. Each of the plurality of comb-like electrode portions 14 and the p-side electrode 11p are interleaved with each other.
  • Each of the plurality of comb-like electrode portions 14 includes a plurality of finger electrode portions 12n as n-side finger electrode portions and a bus bar portion 13n.
  • the plurality of finger electrode portions 12n are arranged along the y direction.
  • Each of the plurality of finger electrode portions 12n extends linearly from the x1 side in the x direction toward the x2 side between the finger electrode portions 12p adjacent in the y direction.
  • the plurality of finger electrode portions 12n are electrically connected by the bus bar portion 13n.
  • the bus bar portion 13n is disposed on the x1 side of the plurality of finger electrode portions 12n.
  • the bus bar portion 13n is formed in a linear shape.
  • the shape of the n-side bus bar portion is not particularly limited as long as a plurality of n-side finger electrode portions are electrically connected.
  • the n-side bus bar portion may not be linear.
  • the n-side bus bar portion may include an electrode pad and a plurality of connection portions that connect the electrode pad and the n-side finger electrode portion.
  • the shortest distance between the bus bar portions 13n of the comb-like electrode portions 14 adjacent in the y direction is preferably 0.001 mm to 10 mm, and more preferably 0.001 mm to 4 mm.
  • finger electrode portions 12p are arranged. That is, the plurality of finger electrode portions 12p include the finger electrode portions 12p1 positioned between the comb-like electrode portions 14 adjacent in the y direction.
  • the finger electrode portion 12p1 is longer than the other finger electrode portions 12p.
  • the tip of the finger electrode portion 12p1 is located between the bus bar portions 13n of the comb-like electrode portions 14 adjacent in the y direction. In other words, the tip of the finger electrode portion 12p1 reaches the position of the bus bar portion 13n in the x direction.
  • the tip of the finger electrode portion 12p1 faces at least a part of the bus bar portion 13n in the y direction.
  • the tip of the finger electrode portion 12p1 on the x1 side is flush with the end of the bus bar portion 13n on the x1 side.
  • the tip end of the finger electrode portion 12p1 on the x1 side may be located on the x2 side with respect to the tip end on the x1 side of the bus bar portion 13n, or may be located on the x1 side with respect to the tip end on the x1 side of the bus bar portion 13n. That is, the finger electrode portion 12p1 only needs to face at least a part of the bus bar portion 13n in the y direction.
  • the finger electrode portion located on the outermost side in the y direction is the finger electrode portion 12p. That is, the plurality of finger electrode portions 12p include the finger electrode portions 12p2 located on the outermost side in the y direction among the plurality of finger electrode portions 12p and the plurality of finger electrode portions 12n.
  • the finger electrode portion 12p2 faces at least a part of the bus bar portion 13n in the y direction. That is, the tip of the finger electrode portion 12p2 reaches the position of the bus bar portion 13n in the x direction.
  • the tip of the finger electrode portion 12p2 on the x1 side and the end of the bus bar portion 13n on the x1 side are flush with each other.
  • the tip end of the finger electrode portion 12p2 on the x1 side may be located on the x2 side with respect to the tip end on the x1 side of the bus bar portion 13n, or may be located on the x1 side with respect to the tip end on the x1 side of the bus bar portion 13n.
  • the n-side electrode 11n is divided into a plurality of comb-like electrode portions 14.
  • the p-side finger electrode portion 12p1 is located between the bus bar portions 13n.
  • the area of the n-side bus bar portion 13n is small.
  • the distance which must move until the holes which are the minority carriers generated in the portion located under the bus bar portion 13n of the solar cell substrate 10 are collected by the p-side electrode 11p is short. Therefore, in this embodiment, the loss
  • the finger electrode portion 12p2 is also provided so as to face the bus bar portion 13n in the y direction, similarly to the finger electrode portion 12p1. Therefore, disappearance due to recombination of holes is more effectively suppressed. Therefore, further improved photoelectric conversion efficiency can be realized.
  • the shortest distance between the bus bar portions 13n is 0.001 mm or more.
  • the photoelectric conversion efficiency may decrease due to an increase in the resistance component.
  • the shortest distance between the bus-bar parts 13n is 10 mm or less, and it is preferable that it is 4 mm or less.
  • FIG. 2 is a schematic plan view of the solar cell according to the second embodiment.
  • the solar cell 2 of the present embodiment differs from the solar cell 1 of the first embodiment in the shape of the bus bar portion 13n and the shape of the finger electrode portion 12p1.
  • the bus bar portion 13n is narrower from the x2 side in the x direction toward the x1 side.
  • the bus bar portion 13n has a trapezoidal shape with the upper base facing the x2 side.
  • the tip of the finger electrode portion 12p1 is wider from the x2 side in the x direction toward the x1 side.
  • the tip of the finger electrode portion 12p1 has a trapezoidal shape with the bottom bottom facing the x1 side.
  • the area of the bus bar portion 13n is smaller than that of the solar cell 1 of the first embodiment.
  • the finger electrode portion 12p1 is wider toward the x1 side, the holes generated in the portion located below the bus bar portion 13n of the solar cell substrate 10 move until they are collected by the p-side electrode 11p. The distance you have to do is getting shorter. Therefore, disappearance due to hole recombination can be more effectively suppressed. Therefore, further improved photoelectric conversion efficiency can be obtained.
  • the base angle of the bus bar portion 13n (and the base angle of the tip portion of the finger electrode portion 12p1) is preferably 0 ° to 90 ° (180 ° to 90 °), and 30 ° to 60 ° (150 ° to 120 °) is more preferable.
  • FIG. 3 is a schematic plan view of a solar cell according to the third embodiment.
  • the solar cell 3 according to the present embodiment is the first embodiment described above in that a plurality of finger electrode portions 12p1 are disposed between the comb-like electrode portions 14 adjacent in the y direction. Different from the solar cell 1 of FIG. Even in this case, improved photoelectric conversion efficiency can be realized as in the first embodiment.
  • FIG. 4 is a schematic plan view of a solar cell according to the fourth embodiment.
  • the solar cell 4 according to the present embodiment is similar to the second embodiment in that each of the front end portions of the bus bar portion 13n and the finger electrode portion 12p1 is formed in a trapezoidal shape. Different from the solar cell 3 of the third embodiment. For this reason, the solar cell 4 of this embodiment has a higher photoelectric conversion efficiency than the solar cell 3.
  • FIG. 5 is a schematic plan view of a solar cell according to the fifth embodiment.
  • FIG. 6 is a schematic plan view in which a part of the solar cell according to the fifth embodiment is enlarged.
  • the solar cell 5 of the present embodiment is different from the solar cell 1 of the first embodiment in that the p-side electrode 11p has an electrode portion 15p.
  • the electrode part 15p is electrically connected to the finger electrode part 12p1. Specifically, in the present embodiment, the electrode portion 15p connects the tip portions of the plurality of finger electrode portions 12p1.
  • the electrode portion 15p is provided on the x1 side of the bus bar portion 13n so as to extend along the y direction.
  • the holes 16 generated in the portion located below the x1 side portion of the bus bar portion 13n in the solar cell substrate 10 are finger electrodes. It must travel a long distance before being collected by the part 12p. Therefore, the holes 16 are likely to disappear due to recombination.
  • the electrode portion 15p as described above is provided. For this reason, as shown in FIG. 6, until the holes 16 generated in the portion located below the x1 side portion of the bus bar portion 13n in the solar cell substrate 10 are collected by the electrode portion 15p of the p-side electrode 11p. The distance you have to move to is short. Therefore, the holes 16 are unlikely to disappear due to recombination. Therefore, more improved photoelectric conversion efficiency can be realized.
  • one conductivity type is n-type and the other conductivity type is p-type.
  • the present invention is not limited to this, and one conductivity type may be p-type and another conductivity type may be n-type. In this case, the same effect as in the case where electrons are minority carriers and holes are minority carriers can be obtained.

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Abstract

A solar cell with improved photoelectric conversion efficiency is provided. An electrode (11p) on the side of an other conductivity type has a plurality of finger electrode sections (12p) on the side of the other conductivity type and a bus bar section (13p) on the side of the other conductivity type that electrically connects the plurality of finger electrode sections (12p) on the side of the other conductivity type. An electrode (11n) on the side of one conductivity type has a plurality of comb-shaped electrode sections (14). Each of the plurality of comb-shaped electrode sections (14) has a plurality of one conductive side finger electrode sections (12n) on the side of the one conductivity type and a bus bar section (13n) on the side of the one conductivity type that electrically connects the plurality of finger electrode sections (12n) on the side of the one conductivity type. The plurality of finger electrode sections (12p) on the side of the other conductivity type include a finger electrode section (12p1) on the side of the other conductivity type, positioned between adjacent comb-shaped electrode sections (14) in a second direction (y). The end section of the finger electrode section (12p1) on the side of the other conductivity type is positioned between bus bar sections (13n) on the side of the one conductivity type in adjacent comb-shaped electrode sections (14).

Description

太陽電池Solar cell
　本発明は、裏面接合型の太陽電池に関する。 The present invention relates to a back junction solar cell.
　従来、太陽電池の裏面側にｐ型及びｎ型の半導体領域が配されている所謂裏面接合型の太陽電池が知られている。例えば、下記の特許文献１には、裏面接合型の太陽電池として、互いに間挿し合うくし歯状のｐ側電極とｎ側電極とが裏面の上に形成された太陽電池が記載されている。この裏面接合型の太陽電池では、受光面側に電極を設ける必要がない。このため、裏面接合型の太陽電池では、光の受光効率を高めることができる。従って、より高い光電変換効率を実現し得る。 Conventionally, a so-called back junction type solar cell in which p-type and n-type semiconductor regions are arranged on the back side of the solar cell is known. For example, Patent Document 1 described below describes a solar cell in which comb-shaped p-side electrodes and n-side electrodes that are interleaved with each other are formed on the back surface as a back surface junction type solar cell. In this back junction solar cell, it is not necessary to provide an electrode on the light receiving surface side. For this reason, in the back junction solar cell, the light receiving efficiency can be increased. Therefore, higher photoelectric conversion efficiency can be realized.
特開２０１０－８０８８７号公報JP 2010-80887 A
　しかしながら、近年、太陽電池に対する光電変換効率向上の要求がさらに高まってきている。 However, in recent years, there has been an increasing demand for improvement in photoelectric conversion efficiency for solar cells.
　本発明は、斯かる点に鑑みて成されたものであり、その目的は、改善された光電変換効率を有する太陽電池を提供することにある。 The present invention has been made in view of such a point, and an object thereof is to provide a solar cell having improved photoelectric conversion efficiency.
　本発明に係る太陽電池は、太陽電池基板と、一導電型側電極と、他導電型側電極とを備えている。太陽電池基板は、一主面に、一導電型表面と他導電型表面とを有する。一導電型側電極は、一導電型表面の上に配されている。他導電型側電極は、他導電型表面の上に配されている。他導電型側電極は、複数の他導電型側フィンガー電極部と、他導電型側バスバー部とを有する。複数の他導電型側フィンガー電極部のそれぞれは、第１の方向の一方側から他方側に向かって延びている。複数の他導電型側フィンガー電極部は、第１の方向に垂直な第２の方向に沿って配列されている。他導電型側バスバー部は、複数の他導電型側フィンガー電極部を電気的に接続している。一導電型側電極は、複数のくし歯状電極部を有する。複数のくし歯状電極部は、第２の方向に沿って配列されている。複数のくし歯状電極部のそれぞれは、複数の一導電型側フィンガー電極部と、一導電型側バスバー部とを有する。複数の一導電型側フィンガー電極部のそれぞれは、第２の方向において隣り合う他導電型側フィンガー電極部間において第１の方向の他方側から一方側に向かって延びている。一導電型側バスバー部は、複数の一導電型側フィンガー電極部を電気的に接続している。複数の他導電型側フィンガー電極部は、第２の方向において隣り合うくし歯状電極部間に位置している他導電型側フィンガー電極部を含む。隣り合うくし歯状電極部間に位置している他導電型側フィンガー電極部の先端部は、隣り合うくし歯状電極部の一導電型側バスバー部間に位置している。 The solar cell according to the present invention includes a solar cell substrate, one conductivity type side electrode, and another conductivity type side electrode. The solar cell substrate has one conductivity type surface and another conductivity type surface on one main surface. The one conductivity type side electrode is arranged on the one conductivity type surface. The other conductivity type side electrode is disposed on the other conductivity type surface. The other conductivity type side electrode has a plurality of other conductivity type side finger electrode portions and another conductivity type side bus bar portions. Each of the plurality of other conductivity type finger electrode portions extends from one side in the first direction toward the other side. The plurality of other conductivity type finger electrode portions are arranged along a second direction perpendicular to the first direction. The other conductivity type side bus bar portion electrically connects a plurality of other conductivity type side finger electrode portions. The one conductivity type side electrode has a plurality of comb-like electrode portions. The plurality of comb-like electrode portions are arranged along the second direction. Each of the plurality of comb-like electrode portions has a plurality of one-conductivity-type finger electrode portions and a one-conductivity-type busbar portion. Each of the plurality of one-conductivity-type finger electrode portions extends from the other side in the first direction toward one side between the other-conductivity-type finger electrode portions adjacent in the second direction. The one conductivity type side bus bar portion electrically connects a plurality of one conductivity type side finger electrode portions. The plurality of other-conductivity-type finger electrode portions include other-conductivity-type finger electrode portions located between the comb-shaped electrode portions adjacent in the second direction. The front end portion of the other conductivity type finger electrode portion located between the adjacent comb-shaped electrode portions is positioned between the one conductivity-type bus bar portions of the adjacent comb-shaped electrode portions.
　本発明によれば、改善された光電変換効率を有する太陽電池を提供することができる。 According to the present invention, a solar cell having improved photoelectric conversion efficiency can be provided.
図１は、第１の実施形態に係る太陽電池の略図的平面図である。FIG. 1 is a schematic plan view of the solar cell according to the first embodiment. 図２は、第２の実施形態に係る太陽電池の略図的平面図である。FIG. 2 is a schematic plan view of the solar cell according to the second embodiment. 図３は、第３の実施形態に係る太陽電池の略図的平面図である。FIG. 3 is a schematic plan view of a solar cell according to the third embodiment. 図４は、第４の実施形態に係る太陽電池の略図的平面図である。FIG. 4 is a schematic plan view of a solar cell according to the fourth embodiment. 図５は、第５の実施形態に係る太陽電池の略図的平面図である。FIG. 5 is a schematic plan view of a solar cell according to the fifth embodiment. 図６は、第５の実施形態に係る太陽電池の一部分を拡大した略図的平面図である。FIG. 6 is a schematic plan view in which a part of the solar cell according to the fifth embodiment is enlarged. 図７は、第１の実施形態に係る太陽電池の一部分を拡大した略図的平面図である。FIG. 7 is a schematic plan view in which a part of the solar cell according to the first embodiment is enlarged.
　以下、本発明を実施した好ましい形態の一例について説明する。但し、以下の実施形態は、単なる例示である。本発明は、以下の実施形態に何ら限定されない。 Hereinafter, an example of a preferable embodiment in which the present invention is implemented will be described. However, the following embodiments are merely examples. The present invention is not limited to the following embodiments.
　また、実施形態等において参照する各図面において、実質的に同一の機能を有する部材は同一の符号で参照することとする。また、実施形態等において参照する図面は、模式的に記載されたものであり、図面に描画された物体の寸法の比率などは、現実の物体の寸法の比率などとは異なる場合がある。図面相互間においても、物体の寸法比率等が異なる場合がある。具体的な物体の寸法比率等は、以下の説明を参酌して判断されるべきである。 In each drawing referred to in the embodiment and the like, members having substantially the same function are referred to by the same reference numerals. The drawings referred to in the embodiments and the like are schematically described, and the ratio of the dimensions of the objects drawn in the drawings may be different from the ratio of the dimensions of the actual objects. The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio of the object should be determined in consideration of the following description.
　（第１の実施形態）
　図１は、本実施形態の太陽電池１の裏面の略図的平面図である。この図１及び下記の図２～図７においては、電極の形状をわかりやすくするためにハッチングを附しているが、図１～図７においてハッチングが附された領域は、断面ではない。 (First embodiment)
FIG. 1 is a schematic plan view of the back surface of the solar cell 1 of the present embodiment. In FIG. 1 and FIGS. 2 to 7 described below, hatching is provided for easy understanding of the shape of the electrode, but the hatched region in FIGS. 1 to 7 is not a cross section.
　太陽電池１は、所謂裏面接合型の太陽電池である。太陽電池１は、太陽電池基板１０を有する。太陽電池基板１０は、受光することによって電子や正孔などのキャリアを生成させる部材である。太陽電池基板１０は、受光面と、裏面１０ａとを有する。裏面１０ａには、ｎ型表面１０ａｎと、ｐ型表面１０ａｐとが露出している。 The solar cell 1 is a so-called back junction type solar cell. The solar cell 1 has a solar cell substrate 10. The solar cell substrate 10 is a member that generates carriers such as electrons and holes by receiving light. Solar cell substrate 10 has a light receiving surface and a back surface 10a. The n-type surface 10an and the p-type surface 10ap are exposed on the back surface 10a.
　太陽電池基板１０は、一導電型を有する結晶性半導体からなる基板と、その半導体基板の裏面の上に配されたｐ型非晶質半導体層及びｎ型非晶質半導体層とを有するものであってもよい。その場合は、ｐ型表面１０ａｐは、ｐ型非晶質半導体層の表面により構成される。ｎ型表面１０ａｎは、ｎ型非晶質半導体層の表面により構成される。 The solar cell substrate 10 includes a substrate made of a crystalline semiconductor having one conductivity type, and a p-type amorphous semiconductor layer and an n-type amorphous semiconductor layer disposed on the back surface of the semiconductor substrate. There may be. In that case, the p-type surface 10ap is constituted by the surface of the p-type amorphous semiconductor layer. The n-type surface 10an is constituted by the surface of the n-type amorphous semiconductor layer.
　なお、ｐ型非晶質半導体層は、例えば、水素を含むｐ型のアモルファスシリコンにより形成することができる。ｎ型非晶質半導体層は、例えば、水素を含むｎ型のアモルファスシリコンにより形成することができる。ｐ型非晶質半導体層及びｎ型非晶質半導体層のそれぞれと、結晶性半導体層との間に、発電に実質的に寄与しない程度の厚みのｉ型非晶質半導体層が配されていてもよい。ｉ型非晶質半導体層は、例えば、水素を含むｉ型のアモルファスシリコンにより形成することができる。 Note that the p-type amorphous semiconductor layer can be formed of, for example, p-type amorphous silicon containing hydrogen. The n-type amorphous semiconductor layer can be formed of, for example, n-type amorphous silicon containing hydrogen. An i-type amorphous semiconductor layer having a thickness that does not substantially contribute to power generation is disposed between each of the p-type amorphous semiconductor layer and the n-type amorphous semiconductor layer and the crystalline semiconductor layer. May be. The i-type amorphous semiconductor layer can be formed of, for example, i-type amorphous silicon containing hydrogen.
　また、太陽電池基板１０は、一導電型を有し、裏面側に、ｐ型ドーパントが拡散したｐ型ドーパント拡散領域及びｎ型ドーパントが拡散したｎ型ドーパント拡散領域が設けられている半導体基板により構成されていてもよい。この場合は、ｐ型表面１０ａｐは、ｐ型ドーパント拡散領域の表面により構成される。ｎ型表面１０ａｎは、ｎ型ドーパント拡散領域の表面により構成される。 Further, the solar cell substrate 10 has one conductivity type, and a semiconductor substrate in which a p-type dopant diffusion region in which a p-type dopant is diffused and an n-type dopant diffusion region in which an n-type dopant is diffused is provided on the back surface side. It may be configured. In this case, the p-type surface 10ap is constituted by the surface of the p-type dopant diffusion region. The n-type surface 10an is constituted by the surface of the n-type dopant diffusion region.
　半導体基板の厚みは、２ｍｍ以下であることが好ましい。半導体基板の厚みの下限は、０．０１ｍｍであることが好ましい。結晶性半導体基板の比抵抗は、０．１Ωｃｍ～１００Ωｃｍであることが好ましい。 The thickness of the semiconductor substrate is preferably 2 mm or less. The lower limit of the thickness of the semiconductor substrate is preferably 0.01 mm. The specific resistance of the crystalline semiconductor substrate is preferably 0.1 Ωcm to 100 Ωcm.
　以下、本実施形態では、太陽電池基板１０が、ｎ型の半導体基板と、半導体基板の裏面の上に配されたｐ型非晶質半導体層及びｎ型非晶質半導体層とを有するものである例について説明する。従って、本実施形態では、一導電型はｎ型であり、正孔が少数キャリアとなる。 Hereinafter, in the present embodiment, the solar cell substrate 10 includes an n-type semiconductor substrate, and a p-type amorphous semiconductor layer and an n-type amorphous semiconductor layer disposed on the back surface of the semiconductor substrate. An example will be described. Accordingly, in this embodiment, one conductivity type is n-type, and holes become minority carriers.
　太陽電池基板１０の裏面１０ａの上には、ｐ側電極１１ｐとｎ側電極１１ｎとが配されている。ｐ側電極１１ｐは、ｐ型表面１０ａｐの上に配されている。ｎ側電極１１ｎは、ｎ型表面１０ａｎの上に配されている。 A p-side electrode 11p and an n-side electrode 11n are disposed on the back surface 10a of the solar cell substrate 10. The p-side electrode 11p is disposed on the p-type surface 10ap. The n-side electrode 11n is disposed on the n-type surface 10an.
　ｐ側電極１１ｐ及びｎ側電極１１ｎの材質は、導電材料である限りにおいて特に限定されない。ｐ側電極１１ｐ及びｎ側電極１１ｎのそれぞれは、例えば、銀、銅、アルミニウム、チタン、ニッケル、クロムなどの金属や、それらの金属のうちの一種以上を含む合金、ＴＣＯ（Ｔｒａｎｓｐａｒｅｎｔ　Ｃｏｎｄｕｃｔｉｖｅ　Ｏｘｉｄｅ）などにより形成することができる。また、ｐ側電極１１ｐ及びｎ側電極１１ｎのそれぞれは、例えば、上記金属や合金、ＴＣＯからなる複数の導電層の積層体により構成されていてもよい。ｐ側電極１１ｐ及びｎ側電極１１ｎのそれぞれは、例えば、スパッタ法、蒸着法、スクリーン印刷法或いはメッキ法等を用いて形成することができる。 The material of the p-side electrode 11p and the n-side electrode 11n is not particularly limited as long as it is a conductive material. Each of the p-side electrode 11p and the n-side electrode 11n includes, for example, a metal such as silver, copper, aluminum, titanium, nickel, or chromium, an alloy containing one or more of these metals, TCO (Transparent Conductive Oxide), and the like. Can be formed. In addition, each of the p-side electrode 11p and the n-side electrode 11n may be configured by a stacked body of a plurality of conductive layers made of, for example, the above metal, alloy, or TCO. Each of the p-side electrode 11p and the n-side electrode 11n can be formed using, for example, a sputtering method, a vapor deposition method, a screen printing method, a plating method, or the like.
　本実施形態では、ｐ側電極１１ｐは、ひとつのくし歯状電極により構成されている。もっとも、本発明においては、ｐ側電極１１ｐは、複数のくし歯状電極により構成されていてもよい。ｐ側電極１１ｐは、ｐ側フィンガー電極部としての複数のフィンガー電極部１２ｐと、ｐ側バスバー部としてのバスバー部１３ｐとを有する。複数のフィンガー電極部１２ｐのそれぞれは、ｘ方向のｘ２側からｘ１側に向かって直線状に延びている。複数のフィンガー電極部１２ｐは、ｘ方向に対して垂直なｙ方向に沿って配列されている。 In the present embodiment, the p-side electrode 11p is composed of one comb-like electrode. However, in the present invention, the p-side electrode 11p may be composed of a plurality of comb-like electrodes. The p-side electrode 11p has a plurality of finger electrode portions 12p as p-side finger electrode portions and a bus bar portion 13p as a p-side bus bar portion. Each of the plurality of finger electrode portions 12p extends linearly from the x2 side in the x direction toward the x1 side. The plurality of finger electrode portions 12p are arranged along the y direction perpendicular to the x direction.
　複数のフィンガー電極部１２ｐは、バスバー部１３ｐにより電気的に接続されている。本実施形態では、バスバー部１３ｐは、複数のフィンガー電極部１２ｐのｘ２側に配置されている。バスバー部１３ｐは、直線状に形成されている。但し、本発明は、この構成に限定されない。本発明において、ｐ側バスバー部の形状は、複数のｐ側フィンガー電極部を電気的に接続している限りにおいて特に限定されない。ｐ側バスバー部は、直線状でなくてもよい。例えば、ｐ側バスバー部は、電極パッドと、その電極パッドとｐ側フィンガー電極部とを接続している複数の接続部とを有するものであってもよい。 The plurality of finger electrode portions 12p are electrically connected by the bus bar portion 13p. In the present embodiment, the bus bar portion 13p is disposed on the x2 side of the plurality of finger electrode portions 12p. The bus bar portion 13p is formed in a linear shape. However, the present invention is not limited to this configuration. In the present invention, the shape of the p-side bus bar portion is not particularly limited as long as a plurality of p-side finger electrode portions are electrically connected. The p-side bus bar portion may not be linear. For example, the p-side bus bar portion may include an electrode pad and a plurality of connection portions that connect the electrode pad and the p-side finger electrode portion.
　本実施形態では、ｎ側電極１１ｎは、複数の電極部に分離されている。具体的には、ｎ側電極１１ｎは、複数のくし歯状電極部１４を有する。ｎ側電極１１ｎに含まれるくし歯状電極部１４の数は、２～５０であることが好ましく、３～５であることがより好ましい。 In this embodiment, the n-side electrode 11n is separated into a plurality of electrode portions. Specifically, the n-side electrode 11n has a plurality of comb-like electrode portions 14. The number of comb-like electrode portions 14 included in the n-side electrode 11n is preferably 2 to 50, and more preferably 3 to 5.
　複数のくし歯状電極部１４は、ｙ方向に沿って配列されている。複数のくし歯状電極部１４のそれぞれと、ｐ側電極１１ｐとは、互いに間挿し合っている。 The plurality of comb-like electrode portions 14 are arranged along the y direction. Each of the plurality of comb-like electrode portions 14 and the p-side electrode 11p are interleaved with each other.
　複数のくし歯状電極部１４のそれぞれは、ｎ側フィンガー電極部としての複数のフィンガー電極部１２ｎと、バスバー部１３ｎとを有する。複数のフィンガー電極部１２ｎは、ｙ方向に沿って配列されている。複数のフィンガー電極部１２ｎのそれぞれは、ｙ方向において隣り合うフィンガー電極部１２ｐ間において、ｘ方向のｘ１側からｘ２側に向かって直線状に延びている。 Each of the plurality of comb-like electrode portions 14 includes a plurality of finger electrode portions 12n as n-side finger electrode portions and a bus bar portion 13n. The plurality of finger electrode portions 12n are arranged along the y direction. Each of the plurality of finger electrode portions 12n extends linearly from the x1 side in the x direction toward the x2 side between the finger electrode portions 12p adjacent in the y direction.
　複数のフィンガー電極部１２ｎは、バスバー部１３ｎによって電気的に接続されている。本実施形態では、バスバー部１３ｎは、複数のフィンガー電極部１２ｎのｘ１側に配置されている。バスバー部１３ｎは、直線状に形成されている。但し、本発明は、この構成に限定されない。本発明において、ｎ側バスバー部の形状は、複数のｎ側フィンガー電極部を電気的に接続している限りにおいて特に限定されない。ｎ側バスバー部は、直線状でなくてもよい。例えば、ｎ側バスバー部は、電極パッドと、その電極パッドとｎ側フィンガー電極部とを接続している複数の接続部とを有するものであってもよい。 The plurality of finger electrode portions 12n are electrically connected by the bus bar portion 13n. In the present embodiment, the bus bar portion 13n is disposed on the x1 side of the plurality of finger electrode portions 12n. The bus bar portion 13n is formed in a linear shape. However, the present invention is not limited to this configuration. In the present invention, the shape of the n-side bus bar portion is not particularly limited as long as a plurality of n-side finger electrode portions are electrically connected. The n-side bus bar portion may not be linear. For example, the n-side bus bar portion may include an electrode pad and a plurality of connection portions that connect the electrode pad and the n-side finger electrode portion.
　ｙ方向において隣り合うくし歯状電極部１４のバスバー部１３ｎ間の最短距離は、０．００１ｍｍ～１０ｍｍであることが好ましく、０．００１ｍｍ～４ｍｍであることがより好ましい。 The shortest distance between the bus bar portions 13n of the comb-like electrode portions 14 adjacent in the y direction is preferably 0.001 mm to 10 mm, and more preferably 0.001 mm to 4 mm.
　ｙ方向において隣り合うくし歯状電極部１４の間には、フィンガー電極部１２ｐが配されている。すなわち、複数のフィンガー電極部１２ｐは、ｙ方向において隣り合うくし歯状電極部１４の間に位置するフィンガー電極部１２ｐ１を含む。このフィンガー電極部１２ｐ１は、他のフィンガー電極部１２ｐよりも長い。フィンガー電極部１２ｐ１の先端部は、ｙ方向において隣り合うくし歯状電極部１４のバスバー部１３ｎ間に位置している。換言すれば、フィンガー電極部１２ｐ１の先端は、ｘ方向において、バスバー部１３ｎの位置にまで至っている。フィンガー電極部１２ｐ１の先端部は、ｙ方向において、バスバー部１３ｎの少なくとも一部と対向している。 Between the comb-like electrode portions 14 adjacent in the y direction, finger electrode portions 12p are arranged. That is, the plurality of finger electrode portions 12p include the finger electrode portions 12p1 positioned between the comb-like electrode portions 14 adjacent in the y direction. The finger electrode portion 12p1 is longer than the other finger electrode portions 12p. The tip of the finger electrode portion 12p1 is located between the bus bar portions 13n of the comb-like electrode portions 14 adjacent in the y direction. In other words, the tip of the finger electrode portion 12p1 reaches the position of the bus bar portion 13n in the x direction. The tip of the finger electrode portion 12p1 faces at least a part of the bus bar portion 13n in the y direction.
　なお、本実施形態では、フィンガー電極部１２ｐ１のｘ１側先端と、バスバー部１３ｎのｘ１側の端辺とは面一となっている。但し、本発明は、この構成に限定されない。フィンガー電極部１２ｐ１のｘ１側先端は、バスバー部１３ｎのｘ１側先端よりもｘ２側に位置していてもよいし、バスバー部１３ｎのｘ１側先端よりもｘ１側に位置していてもよい。すなわち、フィンガー電極部１２ｐ１は、バスバー部１３ｎの少なくとも一部とｙ方向において対向していればよい。 In this embodiment, the tip of the finger electrode portion 12p1 on the x1 side is flush with the end of the bus bar portion 13n on the x1 side. However, the present invention is not limited to this configuration. The tip end of the finger electrode portion 12p1 on the x1 side may be located on the x2 side with respect to the tip end on the x1 side of the bus bar portion 13n, or may be located on the x1 side with respect to the tip end on the x1 side of the bus bar portion 13n. That is, the finger electrode portion 12p1 only needs to face at least a part of the bus bar portion 13n in the y direction.
　複数のフィンガー電極部１２ｐ及び複数のフィンガー電極部１２ｎのうち、ｙ方向における最も外側に位置するフィンガー電極部は、フィンガー電極部１２ｐである。すなわち、複数のフィンガー電極部１２ｐは、複数のフィンガー電極部１２ｐ及び複数のフィンガー電極部１２ｎのうちｙ方向における最も外側に位置するフィンガー電極部１２ｐ２を含む。このフィンガー電極部１２ｐ２は、ｙ方向においてバスバー部１３ｎの少なくとも一部と対向している。すなわち、フィンガー電極部１２ｐ２の先端は、ｘ方向において、バスバー部１３ｎの位置にまで至っている。 Among the plurality of finger electrode portions 12p and the plurality of finger electrode portions 12n, the finger electrode portion located on the outermost side in the y direction is the finger electrode portion 12p. That is, the plurality of finger electrode portions 12p include the finger electrode portions 12p2 located on the outermost side in the y direction among the plurality of finger electrode portions 12p and the plurality of finger electrode portions 12n. The finger electrode portion 12p2 faces at least a part of the bus bar portion 13n in the y direction. That is, the tip of the finger electrode portion 12p2 reaches the position of the bus bar portion 13n in the x direction.
　なお、本実施形態では、フィンガー電極部１２ｐ２のｘ１側先端と、バスバー部１３ｎのｘ１側の端辺とは面一となっている。但し、本発明は、この構成に限定されない。フィンガー電極部１２ｐ２のｘ１側先端は、バスバー部１３ｎのｘ１側先端よりもｘ２側に位置していてもよいし、バスバー部１３ｎのｘ１側先端よりもｘ１側に位置していてもよい。 In this embodiment, the tip of the finger electrode portion 12p2 on the x1 side and the end of the bus bar portion 13n on the x1 side are flush with each other. However, the present invention is not limited to this configuration. The tip end of the finger electrode portion 12p2 on the x1 side may be located on the x2 side with respect to the tip end on the x1 side of the bus bar portion 13n, or may be located on the x1 side with respect to the tip end on the x1 side of the bus bar portion 13n.
　ところで、下記の特許文献１に記載のように、ｎ側電極及びｐ側電極のそれぞれをひとつのくし歯状電極により構成した場合は、光電変換効率を十分に改善することは困難である。これは、太陽電池基板のｎ側電極のバスバー部の下に位置する部分で生じた少数キャリアである正孔がｐ側電極に収集されるまでに移動しなければならない距離が長いために再結合により消失しやすいことによるものと考えられる。 By the way, as described in Patent Document 1 below, when each of the n-side electrode and the p-side electrode is composed of one comb-like electrode, it is difficult to sufficiently improve the photoelectric conversion efficiency. This is because recombination occurs because the holes that are minority carriers generated in the portion located below the bus bar portion of the n-side electrode of the solar cell substrate have to travel before being collected by the p-side electrode. This is probably due to the fact that it is easily lost.
　これに対して本実施形態では、ｎ側電極１１ｎが複数のくし歯状電極部１４に分割されている。そして、ｐ側のフィンガー電極部１２ｐ１がバスバー部１３ｎの間に位置している。このため、ｎ側のバスバー部１３ｎの面積が小さい。また、太陽電池基板１０のバスバー部１３ｎの下に位置する部分で生じた少数キャリアである正孔がｐ側電極１１ｐにより収集されるまでに移動しなければならない距離が短い。よって、本実施形態では、正孔の再結合による消失を効果的に抑制することができる。従って、光電変換効率を改善することができる。 In contrast, in the present embodiment, the n-side electrode 11n is divided into a plurality of comb-like electrode portions 14. The p-side finger electrode portion 12p1 is located between the bus bar portions 13n. For this reason, the area of the n-side bus bar portion 13n is small. Moreover, the distance which must move until the holes which are the minority carriers generated in the portion located under the bus bar portion 13n of the solar cell substrate 10 are collected by the p-side electrode 11p is short. Therefore, in this embodiment, the loss | disappearance by recombination of a hole can be suppressed effectively. Therefore, the photoelectric conversion efficiency can be improved.
　また、本実施形態では、フィンガー電極部１２ｐ２も、フィンガー電極部１２ｐ１と同様に、バスバー部１３ｎとｙ方向において対向するように設けられている。従って、正孔の再結合による消失がより効果的に抑制されている。従って、さらに改善された光電変換効率を実現することができる。 In this embodiment, the finger electrode portion 12p2 is also provided so as to face the bus bar portion 13n in the y direction, similarly to the finger electrode portion 12p1. Therefore, disappearance due to recombination of holes is more effectively suppressed. Therefore, further improved photoelectric conversion efficiency can be realized.
　光電変換効率をより大きく改善する観点からは、バスバー部１３ｎの面積を小さくすることが好ましい。よって、バスバー部１３ｎ間の最短距離を長くすることが好ましい。具体的には、バスバー部１３ｎ間の最短距離は、０．００１ｍｍ以上であることが好ましい。しかしながら、バスバー部１３ｎ間の最短距離を長くしすぎると、抵抗成分の増加等により光電変換効率がかえって低下してしまう場合がある。このため、バスバー部１３ｎ間の最短距離は、１０ｍｍ以下であることが好ましく、４ｍｍ以下であることが好ましい。 From the viewpoint of greatly improving the photoelectric conversion efficiency, it is preferable to reduce the area of the bus bar portion 13n. Therefore, it is preferable to lengthen the shortest distance between the bus bar portions 13n. Specifically, it is preferable that the shortest distance between the bus bar portions 13n is 0.001 mm or more. However, if the shortest distance between the bus bar portions 13n is too long, the photoelectric conversion efficiency may decrease due to an increase in the resistance component. For this reason, it is preferable that the shortest distance between the bus-bar parts 13n is 10 mm or less, and it is preferable that it is 4 mm or less.
　以下、本発明を実施した好ましい形態の他の例について説明する。以下の説明において、上記第１の実施形態と実質的に共通の機能を有する部材を共通の符号で参照し、説明を省略する。 Hereinafter, other examples of preferred embodiments in which the present invention is implemented will be described. In the following description, members having substantially the same functions as those of the first embodiment are referred to by the same reference numerals, and description thereof is omitted.
　（第２の実施形態）
　図２は、第２の実施形態に係る太陽電池の略図的平面図である。 (Second Embodiment)
FIG. 2 is a schematic plan view of the solar cell according to the second embodiment.
　本実施形態の太陽電池２は、バスバー部１３ｎの形状と、フィンガー電極部１２ｐ１の形状とにおいて上記第１の実施形態の太陽電池１と異なる。太陽電池２では、バスバー部１３ｎは、ｘ方向のｘ２側からｘ１側に向かって幅狭となっている。具体的には、バスバー部１３ｎは、ｘ２側に上底が向く台形状である。フィンガー電極部１２ｐ１の先端部は、ｘ方向のｘ２側からｘ１側に向かって幅広となっている。具体的には、フィンガー電極部１２ｐ１の先端部は、ｘ１側に下底が向く台形状である。 The solar cell 2 of the present embodiment differs from the solar cell 1 of the first embodiment in the shape of the bus bar portion 13n and the shape of the finger electrode portion 12p1. In the solar cell 2, the bus bar portion 13n is narrower from the x2 side in the x direction toward the x1 side. Specifically, the bus bar portion 13n has a trapezoidal shape with the upper base facing the x2 side. The tip of the finger electrode portion 12p1 is wider from the x2 side in the x direction toward the x1 side. Specifically, the tip of the finger electrode portion 12p1 has a trapezoidal shape with the bottom bottom facing the x1 side.
　このため、太陽電池２では、上記第１の実施形態の太陽電池１よりも、バスバー部１３ｎの面積が小さくされている。また、フィンガー電極部１２ｐ１がｘ１側に向かって幅広となっているため、太陽電池基板１０のバスバー部１３ｎの下に位置する部分で生じた正孔がｐ側電極１１ｐにより収集されるまでに移動しなければならない距離がより短くなっている。よって、正孔の再結合による消失をより効果的に抑制することができる。従って、さらに改善された光電変換効率を得ることができる。 For this reason, in the solar cell 2, the area of the bus bar portion 13n is smaller than that of the solar cell 1 of the first embodiment. Further, since the finger electrode portion 12p1 is wider toward the x1 side, the holes generated in the portion located below the bus bar portion 13n of the solar cell substrate 10 move until they are collected by the p-side electrode 11p. The distance you have to do is getting shorter. Therefore, disappearance due to hole recombination can be more effectively suppressed. Therefore, further improved photoelectric conversion efficiency can be obtained.
　なお、バスバー部１３ｎの底角（及びフィンガー電極部１２ｐ１の先端部の底角は）、０°～９０°（１８０°～９０°）であることが好ましく、３０°～６０°（１５０°～１２０°）であることがより好ましい。 The base angle of the bus bar portion 13n (and the base angle of the tip portion of the finger electrode portion 12p1) is preferably 0 ° to 90 ° (180 ° to 90 °), and 30 ° to 60 ° (150 ° to 120 °) is more preferable.
　（第３の実施形態）
　図３は、第３の実施形態に係る太陽電池の略図的平面図である。図３に示すように、本実施形態に係る太陽電池３は、ｙ方向において隣り合うくし歯状電極部１４間に複数のフィンガー電極部１２ｐ１が配置されている点で、上記第１の実施形態の太陽電池１と異なる。この場合であっても、上記第１の実施形態と同様に、改善された光電変換効率を実現することができる。 (Third embodiment)
FIG. 3 is a schematic plan view of a solar cell according to the third embodiment. As shown in FIG. 3, the solar cell 3 according to the present embodiment is the first embodiment described above in that a plurality of finger electrode portions 12p1 are disposed between the comb-like electrode portions 14 adjacent in the y direction. Different from the solar cell 1 of FIG. Even in this case, improved photoelectric conversion efficiency can be realized as in the first embodiment.
　（第４の実施形態）
　図４は、第４の実施形態に係る太陽電池の略図的平面図である。図４に示すように、本実施形態に係る太陽電池４は、上記第２の実施形態と同様に、バスバー部１３ｎ及びフィンガー電極部１２ｐ１の先端部のそれぞれが台形状に形成されている点で上記第３の実施形態の太陽電池３と異なる。このため、本実施形態の太陽電池４では、太陽電池３よりもさらに高い光電変換効率を有する。 (Fourth embodiment)
FIG. 4 is a schematic plan view of a solar cell according to the fourth embodiment. As shown in FIG. 4, the solar cell 4 according to the present embodiment is similar to the second embodiment in that each of the front end portions of the bus bar portion 13n and the finger electrode portion 12p1 is formed in a trapezoidal shape. Different from the solar cell 3 of the third embodiment. For this reason, the solar cell 4 of this embodiment has a higher photoelectric conversion efficiency than the solar cell 3.
　（第５の実施形態）
　図５は、第５の実施形態に係る太陽電池の略図的平面図である。図６は、第５の実施形態に係る太陽電池の一部分を拡大した略図的平面図である。図５に示すように、本実施形態の太陽電池５は、ｐ側電極１１ｐが、電極部１５ｐを有する点で、第１の実施形態の太陽電池１と異なる。 (Fifth embodiment)
FIG. 5 is a schematic plan view of a solar cell according to the fifth embodiment. FIG. 6 is a schematic plan view in which a part of the solar cell according to the fifth embodiment is enlarged. As shown in FIG. 5, the solar cell 5 of the present embodiment is different from the solar cell 1 of the first embodiment in that the p-side electrode 11p has an electrode portion 15p.
　電極部１５ｐは、フィンガー電極部１２ｐ１に電気的に接続されている。具体的には、本実施形態では、電極部１５ｐは、複数のフィンガー電極部１２ｐ１の先端部を接続している。電極部１５ｐは、バスバー部１３ｎのｘ１側において、ｙ方向に沿って延びるように設けられている。 The electrode part 15p is electrically connected to the finger electrode part 12p1. Specifically, in the present embodiment, the electrode portion 15p connects the tip portions of the plurality of finger electrode portions 12p1. The electrode portion 15p is provided on the x1 side of the bus bar portion 13n so as to extend along the y direction.
　例えば、第１の実施形態の太陽電池１では、図７に示すように、太陽電池基板１０のうち、バスバー部１３ｎのｘ１側部分の下に位置する部分で生じた正孔１６は、フィンガー電極部１２ｐにより収集されるまでに長い距離を移動しなければならない。従って、正孔１６は、再結合により消失しやすい。 For example, in the solar cell 1 of the first embodiment, as shown in FIG. 7, the holes 16 generated in the portion located below the x1 side portion of the bus bar portion 13n in the solar cell substrate 10 are finger electrodes. It must travel a long distance before being collected by the part 12p. Therefore, the holes 16 are likely to disappear due to recombination.
　それに対して、本実施形態では、上述のような電極部１５ｐが設けられている。このため、図６に示すように、太陽電池基板１０のうち、バスバー部１３ｎのｘ１側部分の下に位置する部分で生じた正孔１６がｐ側電極１１ｐの電極部１５ｐにより収集されるまでに移動しなければならない距離が短い。よって、正孔１６は、再結合により消失し難い。従って、より改善された光電変換効率を実現することができる。 In contrast, in the present embodiment, the electrode portion 15p as described above is provided. For this reason, as shown in FIG. 6, until the holes 16 generated in the portion located below the x1 side portion of the bus bar portion 13n in the solar cell substrate 10 are collected by the electrode portion 15p of the p-side electrode 11p. The distance you have to move to is short. Therefore, the holes 16 are unlikely to disappear due to recombination. Therefore, more improved photoelectric conversion efficiency can be realized.
　なお、上記実施形態では、一導電型をｎ型、他導電型をｐ型として説明を行った。しかし本発明はこれに限られず、一導電型をｐ型、他導電型をｎ型としてもよい。この場合、電子が少数キャリアとなり、正孔が少数キャリアの場合と同様の作用効果を得ることができる。 In the embodiment described above, one conductivity type is n-type and the other conductivity type is p-type. However, the present invention is not limited to this, and one conductivity type may be p-type and another conductivity type may be n-type. In this case, the same effect as in the case where electrons are minority carriers and holes are minority carriers can be obtained.
１～５…太陽電池
１０…太陽電池基板
１０ａ…裏面
１０ａｎ…ｎ型表面
１０ａｐ…ｐ型表面
１１ｎ…ｎ側電極
１１ｐ…ｐ側電極
１２ｎ…フィンガー電極部
１２ｐ…フィンガー電極部
１３ｎ…バスバー部
１３ｐ…バスバー部
１４…くし歯状電極部
１５ｐ…電極部
１６…正孔 DESCRIPTION OF SYMBOLS 1-5 ... Solar cell 10 ... Solar cell board | substrate 10a ... Back surface 10an ... n-type surface 10ap ... p-type surface 11n ... n-side electrode 11p ... p-side electrode 12n ... finger electrode part 12p ... finger electrode part 13n ... bus-bar part 13p ... Busbar part 14 ... comb-like electrode part 15p ... electrode part 16 ... hole

Claims (7)

  1. 　一主面に一導電型表面と他導電型表面とを有する太陽電池基板と、
    　前記一導電型表面の上に配された一導電型側電極と、
    　前記他導電型表面の上に配された他導電型側電極と、
    を備え、
    　前記他導電型側電極は、第１の方向の一方側から他方側に向かって延び、前記第１の方向に垂直な第２の方向に沿って配列された複数の他導電型側フィンガー電極部と、前記複数の他導電型側フィンガー電極部を電気的に接続している他導電型側バスバー部とを有し、
    　前記一導電型側電極は、前記第２の方向に沿って配列されており、前記第２の方向において隣り合う前記他導電型側フィンガー電極部間において前記第１の方向の他方側から一方側に向かって延びる複数の一導電型側フィンガー電極部と、前記複数の一導電型側フィンガー電極部を電気的に接続している一導電型側バスバー部とを有する複数のくし歯状電極部を有し、
    　前記複数の他導電型側フィンガー電極部は、前記第２の方向において隣り合う前記くし歯状電極部間に位置している他導電型側フィンガー電極部を含み、
    　前記隣り合うくし歯状電極部間に位置している他導電型側フィンガー電極部の先端部は、前記隣り合うくし歯状電極部の一導電型側バスバー部間に位置している、太陽電池。     A solar cell substrate having one conductivity type surface and another conductivity type surface on one main surface;
    A one-conductivity-type side electrode disposed on the one-conductivity-type surface;
    Another conductivity type side electrode disposed on the other conductivity type surface;
    With
    The other conductivity type side electrode extends from one side of the first direction toward the other side and is arranged along a second direction perpendicular to the first direction. And another conductivity type side bus bar portion electrically connecting the plurality of other conductivity type side finger electrode portions,
    The one-conductivity-type side electrodes are arranged along the second direction, and the other-conductivity-type finger electrode portions adjacent to each other in the second direction are on the one side from the other side in the first direction. A plurality of comb-like electrode portions each having a plurality of one-conductivity-type finger electrode portions extending toward the surface and a one-conductivity-type bus bar portion electrically connecting the plurality of one-conductivity-type finger electrodes. Have
    The plurality of other-conductivity-type finger electrode portions include other-conductivity-type finger electrode portions located between the comb-shaped electrode portions adjacent in the second direction,
    The solar cell in which the front-end | tip part of the other conductivity type side finger electrode part located between the said adjacent comb-tooth shaped electrode parts is located between the one conductivity type side bus-bar parts of the said adjacent comb-tooth shaped electrode part. .
  2. 　前記太陽電池基板は、前記他導電型側のキャリアが少数キャリアである、請求項１に記載の太陽電池。 The solar cell substrate according to claim 1, wherein the carrier on the other conductivity type side is a minority carrier.
  3. 　前記一導電型側バスバー部は、前記第１の方向の他方側に向かって幅狭となっており、
    　前記隣り合うくし歯状電極部間に位置している他導電型側フィンガー電極部の先端部は、前記第１の方向の他方側に向かって幅広となっている、請求項１または２に記載の太陽電池。     The one conductivity type bus bar portion is narrower toward the other side in the first direction,
    The tip part of the other conductivity type side finger electrode part located between the said adjacent comb-tooth shaped electrode parts is wide toward the other side of the said 1st direction. Solar cells.
  4. 　前記第２の方向において隣り合う前記くし歯状電極部間に複数の他導電型側フィンガー電極部が配されている、請求項１～３のいずれか一項に記載の太陽電池。 The solar cell according to any one of claims 1 to 3, wherein a plurality of other-conductivity-type-side finger electrode portions are arranged between the comb-like electrode portions adjacent in the second direction.
  5. 　前記他導電型側電極は、前記他導電型側フィンガー電極部に電気的に接続されており、前記一導電型側バスバー部よりも前記第１の方向の他方側において前記第２の方向に沿って延びる電極部をさらに有する、請求項１～４のいずれか一項に記載の太陽電池。 The other conductivity type side electrode is electrically connected to the other conductivity type side finger electrode portion, and along the second direction on the other side of the first direction than the one conductivity type bus bar portion. The solar cell according to any one of claims 1 to 4, further comprising an electrode portion extending in a vertical direction.
  6. 　前記隣り合うくし歯状電極部の一導電型側バスバー部間の最短距離が１０ｍｍ以下である、請求項１～５のいずれか一項に記載の太陽電池。 The solar cell according to any one of claims 1 to 5, wherein the shortest distance between the one conductive type bus bar portions of the adjacent comb-shaped electrode portions is 10 mm or less.
  7. 　前記複数の他導電型側フィンガー電極部及び前記複数の一導電型側フィンガー電極部のうち、前記第２の方向における最も外側に位置するフィンガー電極部が前記他導電型側フィンガー電極部であり、当該他導電型側フィンガー電極部の先端部は、前記第２の方向において前記一導電型側バスバー部と対向している、請求項１～６のいずれか一項に記載の太陽電池。 Among the plurality of other conductivity type finger electrode parts and the plurality of one conductivity type finger electrode parts, the finger electrode part located on the outermost side in the second direction is the other conductivity type finger electrode part, The solar cell according to any one of claims 1 to 6, wherein a tip portion of the other conductivity type side finger electrode portion is opposed to the one conductivity type side bus bar portion in the second direction.
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