JP2013004885A

JP2013004885A - Condensing-type solar cell module

Info

Publication number: JP2013004885A
Application number: JP2011136908A
Authority: JP
Inventors: Toru Nakagawa; 徹中川; Teruhiro Ito; 彰宏伊藤; Akio Matsushita; 明生松下
Original assignee: Panasonic Corp
Current assignee: Panasonic Corp
Priority date: 2011-06-21
Filing date: 2011-06-21
Publication date: 2013-01-07

Abstract

PROBLEM TO BE SOLVED: To efficiently release heat generated inside a power generation element to the outside in a condensing-type solar cell module having an integrated structure of a lens and a power generation element.SOLUTION: A condensing-type solar cell module has a lens array 101, a power generation element 103, and a heat releasing plate 102. The power generation element 103 comprises: a power generation layer 201; a first electrode 206: a second electrode 207; a first bump 208; and a second bump 209. In a transmission plane view, the first bump is not overlapping the power generation layer, and a first surface of the power generation layer is connected to the first bump via the first electrode. In the transmission plane view, the second bump is not overlapping the power generation layer, and a second surface of the power generation layer is connected to the second bump via the second electrode. The thickness of the first electrode and the second electrode are greater than the thickness of the power generation layer. The first bump is electrically connected via an anisotropic conductive layer to an electrode formed on the heat releasing plate, and the second pump is electrically connected via an anisotropic conductive layer to an electrode formed via an insulator film on the heat releasing plate.

Description

本発明は集光型太陽電池に関する。 The present invention relates to a concentrating solar cell.

集光型太陽電池は、レンズを用いて発電素子に太陽光を集光して、発電する太陽電池である。発電素子は、光照射によって電流が発生する素子である。発電素子は、１層または数層積層したＰｎ接合からなる半導体層と、半導体層内に発生した電流を外部に取り出すための電極とを有する。 A concentrating solar cell is a solar cell that collects sunlight on a power generation element using a lens to generate power. The power generation element is an element that generates a current by light irradiation. The power generation element includes a semiconductor layer made of a Pn junction in which one layer or several layers are stacked, and an electrode for taking out current generated in the semiconductor layer to the outside.

特許文献１は、レンズの底面に発電素子が直接接触した、レンズと発電素子が一体構造の集光型太陽電池が開示されている。図７に示す集光型太陽電池は、太陽電池チップ７０１のそれぞれに小型のレンズ７０２が配置固着されている。太陽電池チップ７０１は、印刷配線パターンを有する下部基体７０３上に装着されている。下部基体７０３は、発電素子からの熱を除去するための放熱板となる。 Patent Document 1 discloses a concentrating solar cell in which a power generation element is in direct contact with the bottom surface of the lens and the lens and the power generation element are integrated. In the concentrating solar cell shown in FIG. 7, a small lens 702 is disposed and fixed to each solar cell chip 701. The solar cell chip 701 is mounted on a lower base 703 having a printed wiring pattern. The lower base 703 serves as a heat radiating plate for removing heat from the power generation element.

一方、集光型太陽電池においては、発電素子に太陽光が集光されるので、発電素子の温度が上がり太陽電池の発電効率が低下する恐れがある。このため、発電素子で発生した熱を効率よく素子外部に逃がす必要がある。 On the other hand, in a concentrating solar cell, sunlight is concentrated on the power generation element, so that the temperature of the power generation element increases and the power generation efficiency of the solar cell may decrease. For this reason, it is necessary to efficiently release the heat generated in the power generation element to the outside of the element.

特許文献４は、太陽電池セル１４と放熱基台１２との間に、カーボン、ガラス繊維、アルミナ、金属粒子などを混入した樹脂シート２２を入れ、太陽電池セル１４の熱を、放熱基台１２に逃がすことが開示されている。 In Patent Document 4, a resin sheet 22 mixed with carbon, glass fiber, alumina, metal particles and the like is inserted between the solar battery cell 14 and the heat dissipation base 12, and the heat of the solar battery cell 14 is transferred to the heat dissipation base 12. Is disclosed.

特開昭５８−６８９８８号公報Japanese Patent Laid-Open No. 58-68988 特開２００５−１４２３８５号公報JP 2005-142385 A

特許文献２で開示されているカーボン、ガラス繊維、アルミナ、金属粒子などを混入した樹脂シートは、素子の放熱性が悪く、放熱用の銅板２４が必要となる。また、集光用レンズを一体にした構成についての開示はない。
本発明は、かかる課題を解決し、発電素子内で発生した熱を効率良く放熱板に逃がすことが可能な、レンズと発電素子とが一体構造の集光型太陽電池を提供することを目的とする。 The resin sheet mixed with carbon, glass fiber, alumina, metal particles, etc. disclosed in Patent Document 2 has poor heat dissipation of the element, and requires a copper plate 24 for heat dissipation. Further, there is no disclosure about a configuration in which a condensing lens is integrated.
An object of the present invention is to solve such problems and to provide a concentrating solar cell in which a lens and a power generation element are integrated, which can efficiently release heat generated in the power generation element to a heat sink. To do.

従来の課題を解決するために、本発明の集光型太陽電池は、
光入射面を有し、前記光入射面から入射した光を集光するレンズアレイと、
前記レンズアレイにより集光した光を受光し、電気を発生する発電素子と、
前記発電素子に対して前記レンズアレイと対向する側に配置した放熱板とを有する集光型太陽電池であって、
前記発電素子は、
発電層、第１の電極、第２の電極、第１バンプ、第２バンプを含み、
前記発電層は、ｎ型半導体層およびｐ型半導体層を積層し、
透過平面視において、第１バンプが前記発電層に重ならず、
第１電極を介して前記ｎ型半導体層が第１バンプに電気的に接続されており、
透過平面視において、第２バンプが前記発電層に重ならず、
第２電極を介して前記ｐ型半導体層が第２バンプに電気的に接続されており、
前記第１電極及び第２電極の厚みは、前記発電層の厚みよりも大きく、
前記第１バンプは、放熱板上に形成した電極と、異方性導電性膜を介して電気的に接合され、
前記第２バンプは、放熱板上に絶縁膜を介して形成した電極と、異方性導電性膜を介して電気的に接合される。
また、光入射面を有し、前記光入射面から入射した光を集光するレンズアレイと、
前記レンズアレイにより集光した光を受光し、電気を発生する発電素子と、
前記発電素子に対して前記レンズアレイと対向する側に配置した放熱板とを有する集光型太陽電池であって、
前記発電素子は、
発電層、第１の電極、第２の電極、第１バンプ、第２バンプを含み、
前記発電層は、ｎ型半導体層およびｐ型半導体層を積層し、
透過平面視において、第１バンプが前記発電層に重ならず、
第１電極を介して前記ｐ型半導体層が第１バンプに電気的に接続されており、
透過平面視において、第２バンプが前記発電層に重ならず、
第２電極を介して前記ｎ型半導体層が第２バンプに電気的に接続されており、
前記第１電極及び第２電極の厚みは、前記発電層の厚みよりも大きく、
前記第１バンプは、放熱板上に形成した電極と、異方性導電性膜を介して電気的に接合され、
前記第２バンプは、放熱板上に絶縁膜を介して形成した電極と、異方性導電性膜を介して電気的に接合される。 In order to solve the conventional problems, the concentrating solar cell of the present invention is
A lens array that has a light incident surface and collects light incident from the light incident surface;
A power generating element that receives light collected by the lens array and generates electricity;
A concentrating solar cell having a heat radiating plate disposed on the side facing the lens array with respect to the power generation element,
The power generating element is:
Including a power generation layer, a first electrode, a second electrode, a first bump, a second bump,
The power generation layer is formed by laminating an n-type semiconductor layer and a p-type semiconductor layer,
In transmission plan view, the first bump does not overlap the power generation layer,
The n-type semiconductor layer is electrically connected to the first bump via the first electrode;
In transmission plan view, the second bump does not overlap the power generation layer,
The p-type semiconductor layer is electrically connected to the second bump via the second electrode;
The thickness of the first electrode and the second electrode is larger than the thickness of the power generation layer,
The first bump is electrically bonded to an electrode formed on a heat sink via an anisotropic conductive film,
The second bump is electrically joined to an electrode formed on the heat sink via an insulating film via an anisotropic conductive film.
A lens array that has a light incident surface and collects light incident from the light incident surface;
A power generating element that receives light collected by the lens array and generates electricity;
A concentrating solar cell having a heat radiating plate disposed on the side facing the lens array with respect to the power generation element,
The power generating element is:
Including a power generation layer, a first electrode, a second electrode, a first bump, a second bump,
The power generation layer is formed by laminating an n-type semiconductor layer and a p-type semiconductor layer,
In transmission plan view, the first bump does not overlap the power generation layer,
The p-type semiconductor layer is electrically connected to the first bump via the first electrode;
In transmission plan view, the second bump does not overlap the power generation layer,
The n-type semiconductor layer is electrically connected to the second bump via the second electrode;
The thickness of the first electrode and the second electrode is larger than the thickness of the power generation layer,
The first bump is electrically bonded to an electrode formed on a heat sink via an anisotropic conductive film,
The second bump is electrically joined to an electrode formed on the heat sink via an insulating film via an anisotropic conductive film.

本発明の集光型太陽電池は、第１電極と第２電極の厚みが半導体層の厚みよりも大きく、さらに、第１電極と第２電極の一部が素子の外部に位置する。従って、第１と第２電極は、発電素子の放熱板として機能し、素子内部で発生した熱を、早く第１と第２電極に放熱する。 In the concentrating solar cell of the present invention, the thickness of the first electrode and the second electrode is larger than the thickness of the semiconductor layer, and the first electrode and a part of the second electrode are located outside the element. Accordingly, the first and second electrodes function as a heat radiating plate of the power generation element, and heat generated inside the element is quickly radiated to the first and second electrodes.

また、本発明の集光型太陽電池は、第１と第２電極が、それぞれ、異方性導電膜の金属粒子を介して放熱板上に形成された第３と第４電極に接合、又は接触し、第１と第２の電極の熱は、効率良く第３と第４電極を通して放熱板に伝導する。この結果、発電素子内部で発生した熱は効率良く放熱板に伝達される。 In the concentrating solar cell of the present invention, the first and second electrodes are respectively joined to the third and fourth electrodes formed on the heat sink via the metal particles of the anisotropic conductive film, or The heat of the first and second electrodes in contact is efficiently conducted to the heat sink through the third and fourth electrodes. As a result, the heat generated inside the power generation element is efficiently transmitted to the heat sink.

また、異方性導電膜１０４によって、集光用のレンズアレイ１０１、発電素子１０３、放熱板１０２を一体固定でき、レンズアレイに発生した熱も、異方性導電膜１０４を介して放熱板に伝えることができる。 Further, the condensing lens array 101, the power generation element 103, and the heat radiating plate 102 can be integrally fixed by the anisotropic conductive film 104, and the heat generated in the lens array is also transferred to the heat radiating plate via the anisotropic conductive film 104. I can tell you.

(ａ)本発明の集光型太陽電池システムの概略図、(ｂ)図(ａ)のＡ−Ａ部の断面模式図。(a) Schematic diagram of concentrating solar cell system of the present invention, (b) Schematic cross-sectional view of the AA portion of FIG. 本発明の集光型太陽電池の素子近傍の断面模式図。The cross-sectional schematic diagram of the element vicinity of the concentrating solar cell of this invention. 本発明の集光型太陽電池の素子近傍の断面模式図。The cross-sectional schematic diagram of the element vicinity of the concentrating solar cell of this invention. 本発明の集光型太陽電池の素子の平面図と側面図。The top view and side view of the element of the concentrating solar cell of this invention. 本発明の集光型太陽電池の発電素子と放熱板との位置関係を示した平面模式図。The plane schematic diagram which showed the positional relationship of the electric power generating element and heat sink of the concentrating solar cell of this invention. 本発明の集光型太陽電池の発電素子の作製方法を示した断面模式図。The cross-sectional schematic diagram which showed the preparation methods of the electric power generating element of the concentrating solar cell of this invention. 本発明の集光型太陽電池の発電素子の作製方法を示した平面模式図。The plane schematic diagram which showed the preparation methods of the electric power generation element of the concentrating solar cell of this invention. 従来の集光型太陽電池の断面模式図。The cross-sectional schematic diagram of the conventional concentrating solar cell. 従来の太陽電池セルの放熱構造を示す図。The figure which shows the thermal radiation structure of the conventional photovoltaic cell.

本発明の実施態様について説明する。
本発明の一実施態様は、光入射面となる第１面と、前記光入射面に対向する平らな第２面を有するレンズアレイ、ここで、前記第２面近傍に焦点が存在する、および、前記レンズアレイの第２面内に存在する前記焦点の付近に、透明性樹脂を介して接触する複数個の発電素子、および、前記発電素子に対して前記第２面と反対の側に配置した放熱板からなる集光型太陽電池であって、
前記発電素子は、光を照射する第１面とそれに対向する第２面を有する板形状の半導体層、および、前記第１面上に形成された第５電極、および、前記第２面上に形成された第６電極、および、前記第５電極に電気的に接合する板形状の第１電極、および前記第６電極に電気的に接合する板形状の第２電極からなり、
前記第１電極と前記第２電極の厚みが、前記半導体層の厚みよりも大きく、
前記第１電極の一部、および、前記第２電極の一部が前記半導体層の外側に存在し、
前記半導体層の第１面が前記レンズの第二面と対向し、
前記半導体層の外側に位置する第１電極の領域と放熱板上に形成された第３電極、および、前記半導体層の外側に位置する第２電極の領域と放熱板上に形成された第４電極が異方性導電性樹脂で電気的に接合されている。
本発明の一実施態様は、
光入射面（１０８）を有し、前記光入射面から入射した光を集光するレンズアレイ（１０１）と、
前記レンズアレイにより集光した光を受光し、電気を発生する発電素子（１０３）と、
前記発電素子に対して前記レンズアレイと対向する側に配置した放熱板（１０２）とを有する集光型太陽電池であって、
前記発電素子は、
光が入射する第一面（２０１ａ）と、前記第一面に対向する第二面（２０１ｂ）とを有する半導体層（２０１）と、
前記第一面上に形成された第５電極（２０２）と、
前記第二面上に形成された第６電極（２０３）と、
前記第５電極と電気的に接合されるとともに、前記半導体層の厚みよりも大きい厚みを有し、かつ前記半導体層の外周側に端部が突出する第１電極（２０６）と、
前記第６電極と電気的に接合されるとともに、前記半導体層の厚みよりも大きい厚みを有し、かつ前記半導体層の外周側に端部が突出する第２電極（２０７）と、
前記半導体層の外周側に突出した第１電極の端部領域（２０６ｃ）と放熱板上に形成された第３電極（２１０）、
および、前記半導体層の外周側に突出した第２電極の端部領域（２０７ｃ）と放熱板上に形成された第４電極（２１１）を、それぞれ電気的に接合する異方性導電性樹脂（１０４）とを備え、
前記レンズアレイと前記放熱板とは、異方性導電膜によって接合されている。 Embodiments of the present invention will be described.
One embodiment of the present invention includes a lens array having a first surface that is a light incident surface and a flat second surface that faces the light incident surface, wherein a focal point exists in the vicinity of the second surface; and A plurality of power generating elements in contact with each other through a transparent resin in the vicinity of the focal point existing in the second surface of the lens array, and disposed on the side opposite to the second surface with respect to the power generating elements A concentrating solar cell comprising a heat sink,
The power generating element includes a plate-shaped semiconductor layer having a first surface for irradiating light and a second surface facing the first surface, a fifth electrode formed on the first surface, and a second surface on the second surface. The formed sixth electrode, the plate-shaped first electrode that is electrically joined to the fifth electrode, and the plate-shaped second electrode that is electrically joined to the sixth electrode,
A thickness of the first electrode and the second electrode is greater than a thickness of the semiconductor layer;
A part of the first electrode and a part of the second electrode are present outside the semiconductor layer;
The first surface of the semiconductor layer faces the second surface of the lens;
The first electrode region located outside the semiconductor layer and the third electrode formed on the heat sink, and the second electrode region located outside the semiconductor layer and the fourth electrode formed on the heat sink. The electrode is electrically bonded with an anisotropic conductive resin.
One embodiment of the present invention is:
A lens array (101) having a light incident surface (108) and condensing light incident from the light incident surface;
A power generating element (103) that receives light collected by the lens array and generates electricity;
A concentrating solar cell having a heat sink (102) disposed on the side facing the lens array with respect to the power generation element,
The power generating element is:
A semiconductor layer (201) having a first surface (201a) on which light is incident and a second surface (201b) facing the first surface;
A fifth electrode (202) formed on the first surface;
A sixth electrode (203) formed on the second surface;
A first electrode (206) electrically connected to the fifth electrode, having a thickness larger than the thickness of the semiconductor layer, and having an end protruding to the outer peripheral side of the semiconductor layer;
A second electrode (207) electrically connected to the sixth electrode, having a thickness larger than the thickness of the semiconductor layer, and having an end protruding to the outer peripheral side of the semiconductor layer;
An end region (206c) of the first electrode protruding to the outer peripheral side of the semiconductor layer and a third electrode (210) formed on the heat sink;
And the anisotropic conductive resin (Electric conductive resin which electrically joins the edge part area | region (207c) of the 2nd electrode which protruded to the outer peripheral side of the said semiconductor layer, and the 4th electrode (211) formed on the heat sink, respectively. 104)
The lens array and the heat sink are joined by an anisotropic conductive film.

加えて、
第１電極の端部の第一面（２０６ｄ）、第２電極の端部の第一面（２０７ｄ）、及び半導体層の光照射面（２０１ａ）は略同一平面上に位置させ、第１電極の端部の第一面、第２電極の端部の第一面、半導体層の光照射面上に透明樹脂（２１５）を介してレンズアレイを設ける。
また、前記異方性導電膜が、熱硬化性樹脂と金属粒子からなる。
また、前記金属粒子が、金粒子、表面に金を被覆した樹脂粒子、または半田粒子である。
本発明の一実施態様は、
光入射面を有し、前記光入射面から入射した光を集光するレンズアレイと、
前記レンズアレイにより集光した光を受光し、電気を発生する発電素子と、
前記発電素子に対して前記レンズアレイと対向する側に配置した放熱板とを有する集光型太陽電池であって、
前記発電素子は、
発電層、第１の電極、第２の電極、第１バンプ、第２バンプを含み、
前記発電層は、ｎ型半導体層およびｐ型半導体層を積層し、
透過平面視において、第１バンプが前記発電層に重ならず、
第１電極を介して前記ｎ型半導体層が第１バンプに電気的に接続されており、
透過平面視において、第２バンプが前記発電層に重ならず、
第２電極を介して前記ｐ型半導体層が第２バンプに電気的に接続されており、
前記第１電極及び第２電極の厚みは、前記発電層の厚みよりも大きく、
前記第１バンプは、放熱板上に形成した電極と、異方性導電性膜を介して電気的に接合され、
前記第２バンプは、放熱板上に絶縁膜を介して形成した電極と、異方性導電性膜を介して電気的に接合される。
本発明の一実施態様は、
光入射面を有し、前記光入射面から入射した光を集光するレンズアレイと、
前記レンズアレイにより集光した光を受光し、電気を発生する発電素子と、
前記発電素子に対して前記レンズアレイと対向する側に配置した放熱板とを有する集光型太陽電池であって、
前記発電素子は、
発電層、第１の電極、第２の電極、第１バンプ、第２バンプを含み、
前記発電層は、ｎ型半導体層およびｐ型半導体層を積層し、
透過平面視において、第１バンプが前記発電層に重ならず、
第１電極を介して前記ｐ型半導体層が第１バンプに電気的に接続されており、
透過平面視において、第２バンプが前記発電層に重ならず、
第２電極を介して前記ｎ型半導体層が第２バンプに電気的に接続されており、
前記第１電極及び第２電極の厚みは、前記発電層の厚みよりも大きく、
前記第１バンプは、放熱板上に形成した電極と、異方性導電性膜を介して電気的に接合され、
前記第２バンプは、放熱板上に絶縁膜を介して形成した電極と、異方性導電性膜を介して電気的に接合される。
更に、
第１電極は、半導体層における光入射面側の第一面上に形成される第５電極と、前記第５電極に電気的に接続される電極とからなり、
第２電極は、前記第一面と対向する第二面上に形成される第６電極と、前記第６電極と電気的に接続される電極とからなる。
以下本発明の実施の形態について、図面を参照しながら説明する。 in addition,
The first surface (206d) of the end portion of the first electrode, the first surface (207d) of the end portion of the second electrode, and the light irradiation surface (201a) of the semiconductor layer are positioned on substantially the same plane. A lens array is provided via a transparent resin (215) on the first surface of the first electrode, the first surface of the second electrode, and the light irradiation surface of the semiconductor layer.
The anisotropic conductive film is made of a thermosetting resin and metal particles.
The metal particles are gold particles, resin particles whose surfaces are coated with gold, or solder particles.
One embodiment of the present invention is:
A lens array that has a light incident surface and collects light incident from the light incident surface;
A power generating element that receives light collected by the lens array and generates electricity;
A concentrating solar cell having a heat radiating plate disposed on the side facing the lens array with respect to the power generation element,
The power generating element is:
Including a power generation layer, a first electrode, a second electrode, a first bump, a second bump,
The power generation layer is formed by laminating an n-type semiconductor layer and a p-type semiconductor layer,
In transmission plan view, the first bump does not overlap the power generation layer,
The n-type semiconductor layer is electrically connected to the first bump via the first electrode;
In transmission plan view, the second bump does not overlap the power generation layer,
The p-type semiconductor layer is electrically connected to the second bump via the second electrode;
The thickness of the first electrode and the second electrode is larger than the thickness of the power generation layer,
The first bump is electrically bonded to an electrode formed on a heat sink via an anisotropic conductive film,
The second bump is electrically joined to an electrode formed on the heat sink via an insulating film via an anisotropic conductive film.
One embodiment of the present invention is:
A lens array that has a light incident surface and collects light incident from the light incident surface;
A power generating element that receives light collected by the lens array and generates electricity;
A concentrating solar cell having a heat radiating plate disposed on the side facing the lens array with respect to the power generation element,
The power generating element is:
Including a power generation layer, a first electrode, a second electrode, a first bump, a second bump,
The power generation layer is formed by laminating an n-type semiconductor layer and a p-type semiconductor layer,
In transmission plan view, the first bump does not overlap the power generation layer,
The p-type semiconductor layer is electrically connected to the first bump via the first electrode;
In transmission plan view, the second bump does not overlap the power generation layer,
The n-type semiconductor layer is electrically connected to the second bump via the second electrode;
The thickness of the first electrode and the second electrode is larger than the thickness of the power generation layer,
The first bump is electrically bonded to an electrode formed on a heat sink via an anisotropic conductive film,
The second bump is electrically joined to an electrode formed on the heat sink via an insulating film via an anisotropic conductive film.
Furthermore,
The first electrode includes a fifth electrode formed on the first surface on the light incident surface side in the semiconductor layer, and an electrode electrically connected to the fifth electrode,
The second electrode includes a sixth electrode formed on the second surface facing the first surface, and an electrode electrically connected to the sixth electrode.
Embodiments of the present invention will be described below with reference to the drawings.

本実施の形態では、本発明の集光型太陽電池の具体的な構造を示す。 In this embodiment, a specific structure of the concentrating solar cell of the present invention is shown.

図１（ａ）は、本発明の一実施形態における集光型太陽電池システムの模式図である。図１（ｂ）は、図１(ａ)の集光型太陽電池１００のＡ-Ａ面における断面模式図である。
集光型太陽電池システム１０７は、集光型太陽電池１００と、集光型太陽電池１００を支える支柱１０５、台１０６、集光型太陽電池を動かして太陽光を追尾するための駆動装置（図示せず）から構成される。
集光型太陽電池１００は、集光用のレンズアレイ１０１、発電素子１０３、放熱板１０２とを順に配置されている。
レンズアレイ１０１は、太陽光が入射する第１面１０８と、第１面１０８に対向する第２面１０９から構成され、太陽光を集光する。本実施形態の集光型太陽電池は、対向する第２面１０９が平面形状であり、第２面１０９内近傍にレンズの焦点が存在する。
レンズアレイ１０１は、太陽光を集光するレンズを二次元に配列した構造を有する。図１（ａ）で示すレンズアレイは、光入射側から個々のレンズを見た時のレンズの平面形状は四角形である。レンズ形状は四角形に限る必要はなく、多角形でも良い。例えば、個々のレンズの平面形状が六角形の場、レンズアレイは、個々のレンズが蜂の巣状に配置された構造となる。 Fig.1 (a) is a schematic diagram of the concentrating solar cell system in one Embodiment of this invention. FIG.1 (b) is a cross-sectional schematic diagram in the AA surface of the concentrating solar cell 100 of Fig.1 (a).
The concentrating solar cell system 107 includes a concentrating solar cell 100, a column 105 that supports the concentrating solar cell 100, a base 106, and a drive device for tracking sunlight by moving the concentrating solar cell (see FIG. (Not shown).
In the concentrating solar cell 100, a condensing lens array 101, a power generation element 103, and a heat radiating plate 102 are arranged in this order.
The lens array 101 includes a first surface 108 on which sunlight is incident and a second surface 109 facing the first surface 108, and condenses the sunlight. In the concentrating solar cell of this embodiment, the second surface 109 facing is a planar shape, and the focal point of the lens exists in the vicinity of the second surface 109.
The lens array 101 has a structure in which lenses that collect sunlight are two-dimensionally arranged. In the lens array shown in FIG. 1A, the planar shape of each lens when viewed from the light incident side is a quadrangle. The lens shape is not limited to a quadrangle, and may be a polygon. For example, when the planar shape of each lens is a hexagon, the lens array has a structure in which individual lenses are arranged in a honeycomb shape.

図１（ｂ）で示すように、発電素子１０３は、接着剤としての透明樹脂２１５を介して、レンズアレイの第２面１０９の焦点付近に接触している。放熱板１０２は、発電素子１０３に対して、レンズアレイの第２面１０９とは反対側に配置されている。本実施形態の集光型太陽電池１００は、レンズアレイ１０１と放熱板１０２によって発電素子１０３をはさんだ構造になっている。 As shown in FIG. 1B, the power generation element 103 is in contact with the vicinity of the focal point of the second surface 109 of the lens array via a transparent resin 215 as an adhesive. The heat radiating plate 102 is disposed on the opposite side of the power generation element 103 from the second surface 109 of the lens array. The concentrating solar cell 100 of this embodiment has a structure in which a power generation element 103 is sandwiched between a lens array 101 and a heat sink 102.

図２は、一個の発電素子１０３の近傍の断面模式図である。図３（ａ）は発電素子の側面図、図３（ｂ）は下面図、図３（ｃ）は上面図である。
図２Ａ、図２Ｂ、図３を用いて本実施形態の集光型太陽電池に用いる発電素子の構造を説明する。
発電素子１０３は、半導体層２０１（発電層）、半導体層２０１の光照射面側２０１ａに形成した第５電極２０２、光照射面２０１ａと対向する面側２０１ｂに形成した第６電極２０３、板形状の第１電極２０６、板形状の第２電極２０７を有する。
第１電極２０６は、第５電極２０２と電気的に接続しており、図２に示すように第一端部２０６ａ、中間部２０６ｂ、第二端部２０６ｃを有する。第一端部２０６ａは、第６電極２０３側に絶縁膜２０４を介して位置し、中間部２０６ｂで屈曲し、第二端部２０６ｃは半導体層２０１の外周側から突出する。第１電極２０６の中間部２０６ｂ、端部２０６ｃの部分が、接続用金属膜２０５を介して第５電極２０２と電気的に接続している。
第２電極２０７は、第６電極２０３と電気的に接続しており、図２に示すように第三端部２０７ａ、中間部２０７ｂ、第四端部２０７ｃを有する。端部２０７ａは第６電極２０３に接続され、中間部２０７ｂで屈曲し、端部２０７ｃは半導体層２０１の外周側から突出する。
第１電極２０６の端部２０６ｃの第一面２０６ｄと、第２電極の端部２０７ｃの第一面２０７ｄは、半導体層２０１の光照射面２０１ａ（第５電極２０２を含む）と略同一平面上になるように構成されている。
本実施形態の、第１電極２０６と第２電極２０７は、図２に示すように、屈曲した形状であり、端部（２０６ａ、２０７ａ）、中間部（２０６ｂ、２０７ｂ）、端部（２０６ｃ、２０６ｃ）の各厚み（ｔ１、ｔ２、ｔ３）は均一でない。
ここで、厚み（ｔ１，ｔ２，ｔ３）は、電極の一端から他端における各位置の厚みである。
本実施形態の第１電極と第２電極の厚みとは、電極を構成する最小の厚み（ｔ１、ｔ２、ｔ３の中で最小の厚み）と定義する。
また、第１電極２０６と第２電極２０７の厚みは、半導体層２０１の厚みよりも大きい。第１電極と第２電極の厚みに制限はないが、半導体層２０１の厚みの１．５〜３倍が望ましい。３倍よりも大きくすると、第３と第４電極形成時に発生した応力により半導体層が割れる場合がある。
第１電極２０６と第２電極２０７とは、絶縁膜２０４によって電気的に絶縁されている。
第１電極２０６の端部２０６ｃの第二面２０６ｅ及び第２電極２０７の端部２０７ｃの第二面２０７ｅ上には、それぞれ、第１バンプ２０８と第２バンプ２０９が形成されている。バンプ材料にはＡｕを用いることが望ましい。
図２、３に示すように、発電素子は、発電層（半導体層）、第１の電極、第２の電極、第１バンプ、第２バンプを含む。前記発電層は、ｎ型半導体層およびｐ型半導体層を積層し、前記ｎ型半導体層は前記ｐ型半導体層上に積層しており、透過平面視において、第１バンプが前記発電層に重ならず、第１電極を介して前記ｎ型半導体層が第１バンプに電気的に接続されており、透過平面視において、第２バンプが前記発電層に重ならず、第２電極を介して前記ｐ型半導体層が第２バンプに電気的に接続されている。
また、ｐ型半導体層とｎ型半導体層とを入れ替えた構造でもよい。すなわち、
発電素子は、発電層（半導体層）、第１の電極、第２の電極、第１バンプ、第２バンプを含む。前記発電層は、ｎ型半導体層およびｐ型半導体層を積層し、前記ｐ型半導体層は前記ｎ型半導体層上に積層しており、透過平面視において、第１バンプが前記発電層に重ならず、第１電極を介して前記ｐ型半導体層が第１バンプに電気的に接続されており、透過平面視において、第２バンプが前記発電層に重ならず、第２電極を介して前記ｎ型半導体層が第２バンプに電気的に接続されている。 FIG. 2 is a schematic cross-sectional view of the vicinity of one power generating element 103. 3A is a side view of the power generation element, FIG. 3B is a bottom view, and FIG. 3C is a top view.
The structure of the power generation element used in the concentrating solar cell of this embodiment will be described with reference to FIGS. 2A, 2B, and 3.
The power generation element 103 includes a semiconductor layer 201 (power generation layer), a fifth electrode 202 formed on the light irradiation surface side 201a of the semiconductor layer 201, a sixth electrode 203 formed on the surface side 201b facing the light irradiation surface 201a, and a plate shape The first electrode 206 and the plate-like second electrode 207 are provided.
The first electrode 206 is electrically connected to the fifth electrode 202 and has a first end portion 206a, an intermediate portion 206b, and a second end portion 206c as shown in FIG. The first end portion 206 a is located on the sixth electrode 203 side through the insulating film 204, is bent at the intermediate portion 206 b, and the second end portion 206 c protrudes from the outer peripheral side of the semiconductor layer 201. The intermediate portion 206 b and the end portion 206 c of the first electrode 206 are electrically connected to the fifth electrode 202 through the connection metal film 205.
The second electrode 207 is electrically connected to the sixth electrode 203 and has a third end 207a, an intermediate portion 207b, and a fourth end 207c as shown in FIG. The end portion 207 a is connected to the sixth electrode 203, is bent at the intermediate portion 207 b, and the end portion 207 c protrudes from the outer peripheral side of the semiconductor layer 201.
The first surface 206d of the end portion 206c of the first electrode 206 and the first surface 207d of the end portion 207c of the second electrode are substantially flush with the light irradiation surface 201a (including the fifth electrode 202) of the semiconductor layer 201. It is configured to be.
As shown in FIG. 2, the first electrode 206 and the second electrode 207 of the present embodiment have a bent shape, and end portions (206a, 207a), intermediate portions (206b, 207b), end portions (206c, Each thickness (t1, t2, t3) of 206c) is not uniform.
Here, the thickness (t1, t2, t3) is a thickness at each position from one end of the electrode to the other end.
The thicknesses of the first electrode and the second electrode in the present embodiment are defined as the minimum thickness (the minimum thickness among t1, t2, and t3) constituting the electrode.
The thicknesses of the first electrode 206 and the second electrode 207 are larger than the thickness of the semiconductor layer 201. Although there is no restriction | limiting in the thickness of a 1st electrode and a 2nd electrode, 1.5 to 3 times the thickness of the semiconductor layer 201 is desirable. If it is larger than 3 times, the semiconductor layer may break due to the stress generated when the third and fourth electrodes are formed.
The first electrode 206 and the second electrode 207 are electrically insulated by the insulating film 204.
A first bump 208 and a second bump 209 are formed on the second surface 206e of the end portion 206c of the first electrode 206 and the second surface 207e of the end portion 207c of the second electrode 207, respectively. It is desirable to use Au as the bump material.
As shown in FIGS. 2 and 3, the power generation element includes a power generation layer (semiconductor layer), a first electrode, a second electrode, a first bump, and a second bump. The power generation layer includes an n-type semiconductor layer and a p-type semiconductor layer, the n-type semiconductor layer is stacked on the p-type semiconductor layer, and the first bump overlaps the power generation layer in a transmission plan view. In addition, the n-type semiconductor layer is electrically connected to the first bump via the first electrode, and the second bump does not overlap the power generation layer in the transmission plan view. The p-type semiconductor layer is electrically connected to the second bump.
Moreover, the structure which replaced the p-type semiconductor layer and the n-type semiconductor layer may be sufficient. That is,
The power generation element includes a power generation layer (semiconductor layer), a first electrode, a second electrode, a first bump, and a second bump. The power generation layer includes an n-type semiconductor layer and a p-type semiconductor layer, the p-type semiconductor layer is stacked on the n-type semiconductor layer, and the first bump overlaps the power generation layer in a transmission plan view. In addition, the p-type semiconductor layer is electrically connected to the first bump via the first electrode, and the second bump does not overlap the power generation layer in the transmission plan view. The n-type semiconductor layer is electrically connected to the second bump.

半導体層（発電層）２０１は、ｐｎ接合が積層された構造を含めば特に制限はない。例えば、半導体層としては、ｎ型のＧａＡｓ薄膜とｐ型のＧａＡｓ薄膜が積層されたもの、または、光入射面から順に、ｎ型ＩｎＧａＰ膜、ｐ型ＩｎＧａＰ膜、トンネル接合膜、ｎ型ＧａＡｓ膜、ｐ型ＧａＡｓ膜、トンネル接合膜、ｎ型ＩｎＧａＡｓ膜、ｐ型ＩｎＧａＰ膜が積層されたものがある。また、上記半導体層のｐｎ接合の順序が反対でも良い。この場合、ｎｐ接合が積層された構造となる。第１電極と第２電極に接触する部分に、低効率の低いコンタクト層を挿入しても良い。また、光電流の再結合を防ぐために、再結合防止用の薄膜を挿入しても良い。 The semiconductor layer (power generation layer) 201 is not particularly limited as long as it includes a structure in which pn junctions are stacked. For example, as the semiconductor layer, an n-type GaAs thin film and a p-type GaAs thin film are laminated, or an n-type InGaP film, a p-type InGaP film, a tunnel junction film, and an n-type GaAs film in order from the light incident surface. , A p-type GaAs film, a tunnel junction film, an n-type InGaAs film, and a p-type InGaP film. Further, the order of the pn junctions of the semiconductor layers may be reversed. In this case, an np junction is stacked. A contact layer with low efficiency may be inserted in a portion in contact with the first electrode and the second electrode. In order to prevent photocurrent recombination, a thin film for preventing recombination may be inserted.

第５電極と第６電極の材料は、半導体層２０１とオーミック接続するものが好ましく、例えばＴｉとＡｕの積層膜、Ｔｉ、Ｐｔ、Ａｕの積層膜、ＡｕＧｅ合金、Ｎｉ、Ａｕの積層膜を使用することができる。第５電極２０２は、図３（ｃ）で示すように、櫛型状であることが望ましい。櫛型形状にすることで、発電素子に照射された太陽光が半導体層２０１に入射して吸収される。
第１電極２０６と第２電極２０７の材料は、Ａｕ又はＮｉを使用することができる。
図２を用いて、本発明の集光型太陽電池の構造を示す。
発電素子１０３は、第５電極２０２の面がレンズアレイの第２面１０９に透明樹脂２１５を介して配置されている。透明樹脂２１５としては、アクリル系接着性樹脂を用いることができる。また第１電極２０６の端部２０６ｃは接続用金属膜２０５を介して、第２電極２０７の端部２０７ｃは、絶縁膜２０４を介して、それぞれ、透明樹脂２１５に接触している。
本実施の形態では、第１電極２０６と第２電極２０７上に、それぞれ、第１バンプ２０８と第２バンプ２０９が形成されている。第１バンプ２０８と第２バンプ２０９は、それぞれ、異方性導電膜１０４によって、放熱板１０２上の第３電極２１０と第４電極２１１に電気的に接続されている。第１バンプ２０８と第３電極２１０の間、および、第２バンプ２０９と第４電極２１１の間に金属粒子２１３が複数個存在する。そして、
第１バンプ２０８及び第２バンプ２０９と、金属粒子２１３、
第３電極２１０及び第４電極２１１と、金属粒子２１３、
金属粒子２１３同士が接触または接合することにより、電気的に接続される。バンプがない場合に比べて、バンプがある方が電気接続しやすいが、バンプを用いなくても接続は可能である。第１電極２０６と第２電極２０７とを金属粒子２１３を用いて、第３電極２１０、第４電極２１１と接合しても良い。 The material of the fifth electrode and the sixth electrode is preferably one that is in ohmic contact with the semiconductor layer 201. For example, a laminated film of Ti and Au, a laminated film of Ti, Pt, Au, an AuGe alloy, a laminated film of Ni, Au is used. can do. The fifth electrode 202 is preferably comb-shaped as shown in FIG. By adopting a comb shape, sunlight irradiated to the power generation element enters the semiconductor layer 201 and is absorbed.
Au or Ni can be used for the material of the first electrode 206 and the second electrode 207.
The structure of the concentrating solar cell of the present invention is shown using FIG.
In the power generation element 103, the surface of the fifth electrode 202 is disposed on the second surface 109 of the lens array via a transparent resin 215. As the transparent resin 215, an acrylic adhesive resin can be used. Further, the end portion 206c of the first electrode 206 is in contact with the transparent resin 215 via the connecting metal film 205, and the end portion 207c of the second electrode 207 is in contact with the transparent resin 215, respectively.
In the present embodiment, a first bump 208 and a second bump 209 are formed on the first electrode 206 and the second electrode 207, respectively. The first bump 208 and the second bump 209 are electrically connected to the third electrode 210 and the fourth electrode 211 on the heat sink 102 by the anisotropic conductive film 104, respectively. A plurality of metal particles 213 exist between the first bump 208 and the third electrode 210 and between the second bump 209 and the fourth electrode 211. And
A first bump 208 and a second bump 209, a metal particle 213,
A third electrode 210 and a fourth electrode 211, a metal particle 213,
The metal particles 213 are electrically connected by contact or bonding. Compared to the case without bumps, it is easier to make electrical connection with bumps, but connection is possible without using bumps. The first electrode 206 and the second electrode 207 may be joined to the third electrode 210 and the fourth electrode 211 using metal particles 213.

上述したように、異方性導電膜１０４は、発電素子１０３と放熱板１０２に形成した第３電極２１０及び第４電極２１１とを電気的に接合すると同時に、放熱板１０２とレンズアレイ１０１とを接着固定する。
異方性導電膜１０４によって、レンズアレイ１０１、発電素子１０３、放熱板１０２を一体固定でき、レンズアレイに発生した熱も、異方性導電膜１０４を介して放熱板に伝えることができる。
第１電極２０６の端部２０６ｃの第一面２０６ｄと、第２電極の端部２０７ｃの第一面２０７ｄは、半導体層２０１の光照射面２０１ａ（第５電極２０２を含む）と略同一平面上にし、第一面２０６ｄ、第一面２０７ｄ、光照射面２０１ａ上に、透明樹脂を介してレンズアレイ１０１を設けることにより、発電素子１０３とレンズアレイ１０１との平行度を精度よく保つことができる。
放熱板１０２の材料としてはアルミニウムや銅を用いることができる。放熱板１０２は、第３電極２１０と電気的に接続されている。放熱板１０２は、絶縁膜２１２によって第４電極２１１と電気的に絶縁されている。この結果、第３電極２１０と第４電極２１１は電気的に絶縁されている。 As described above, the anisotropic conductive film 104 electrically connects the power generation element 103 and the third electrode 210 and the fourth electrode 211 formed on the heat sink 102, and at the same time, connects the heat sink 102 and the lens array 101. Adhere and fix.
The lens array 101, the power generating element 103, and the heat radiating plate 102 can be fixed integrally with the anisotropic conductive film 104, and heat generated in the lens array can be transmitted to the heat radiating plate through the anisotropic conductive film 104.
The first surface 206d of the end portion 206c of the first electrode 206 and the first surface 207d of the end portion 207c of the second electrode are substantially flush with the light irradiation surface 201a (including the fifth electrode 202) of the semiconductor layer 201. In addition, by providing the lens array 101 via the transparent resin on the first surface 206d, the first surface 207d, and the light irradiation surface 201a, the parallelism between the power generation element 103 and the lens array 101 can be accurately maintained. .
Aluminum or copper can be used as the material of the heat sink 102. The heat sink 102 is electrically connected to the third electrode 210. The heat sink 102 is electrically insulated from the fourth electrode 211 by the insulating film 212. As a result, the third electrode 210 and the fourth electrode 211 are electrically insulated.

異方性導電膜１０４は、金属粒子２１３が熱硬化性樹脂２１４に均一に分散した構造を有する。金属粒子には、Ａｕ、ＡｕやＮｉで被覆された樹脂粒子、またはハンダ粒子を用いることができる。 The anisotropic conductive film 104 has a structure in which the metal particles 213 are uniformly dispersed in the thermosetting resin 214. As the metal particles, resin particles coated with Au, Au or Ni, or solder particles can be used.

図４は、放熱板１０２をレンズアレイ１０１側から見た平面模式図である。図では、発電素子１０３が４個の場合を記載しているが、これ以上の数でも良い。また、理解しやすいように、図４では、レンズアレイ１０１と、発電素子１０３周辺の異方性導電膜１０４は省略されている。
発電素子１０３における各々の第５電極２０２は、接続用金属膜２０５、第１電極２０６、（第１バンプ２０８）、金属粒子２１３、第３電極２１０を介して放熱板１０２と電気的に接続させている。発電素子１０３のおける各々の第６電極２０３は、第２電極２０７、（第２バンプ２０９）、金属粒子２１３を介して第４電極２１１に電気的に接続されている。第４電極２１１は、共通電極４０１に電気的に接続されている。第４電極２１１と共通電極４０１とは、絶縁膜２１２によって放熱板１０２と電気的に絶縁されている。
このように、本実施形態の集光型太陽電池は、電気回路的には、発電素子１０３が並列接続された構造を有する。複数の発電素子１０３で発電した電気エネルギーは、外部取り出し線４０２、４０３によって外部に取り出すことができる。
本実施形態の集光型太陽電池においては、発電素子上の第５電極２０２と第６電極２０３に、それぞれ、板形状の第１電極２０６と板形状の第２電極２０７が電気的に接合する構造を有する。この構造によって、半導体層２０１内部で発生した熱は、第５電極２０２と第６電極２０３を介して、第１電極２０６と第２電極２０７に伝わる。
また、本実施の形態の集光型太陽電池においては、板形状の第１電極２０６と第２電極２０７の厚みが半導体層２０１の膜厚よりも大きく、さらに、第１電極２０６と第２電極２０７の一部は半導体層２０１の外部に位置することを特徴とする。
従って、第１電極２０６と第２電極は、発電素子１０３の放熱板として働き、半導体層２０１内部で発生した熱が第１電極２０６と第２電極２０７に放熱される。 FIG. 4 is a schematic plan view of the heat radiating plate 102 as viewed from the lens array 101 side. In the figure, the case where there are four power generating elements 103 is shown, but a number larger than this may be used. For ease of understanding, in FIG. 4, the lens array 101 and the anisotropic conductive film 104 around the power generation element 103 are omitted.
Each fifth electrode 202 in the power generation element 103 is electrically connected to the heat sink 102 via the connection metal film 205, the first electrode 206, the (first bump 208), the metal particles 213, and the third electrode 210. ing. Each sixth electrode 203 in the power generation element 103 is electrically connected to the fourth electrode 211 via the second electrode 207, the (second bump 209), and the metal particles 213. The fourth electrode 211 is electrically connected to the common electrode 401. The fourth electrode 211 and the common electrode 401 are electrically insulated from the heat sink 102 by the insulating film 212.
As described above, the concentrating solar cell according to the present embodiment has a structure in which the power generation elements 103 are connected in parallel in terms of an electric circuit. Electric energy generated by the plurality of power generation elements 103 can be extracted to the outside through the external extraction lines 402 and 403.
In the concentrating solar cell of this embodiment, the plate-shaped first electrode 206 and the plate-shaped second electrode 207 are electrically joined to the fifth electrode 202 and the sixth electrode 203 on the power generation element, respectively. It has a structure. With this structure, heat generated in the semiconductor layer 201 is transmitted to the first electrode 206 and the second electrode 207 through the fifth electrode 202 and the sixth electrode 203.
In the concentrating solar cell of the present embodiment, the thickness of the plate-shaped first electrode 206 and the second electrode 207 is larger than the thickness of the semiconductor layer 201, and the first electrode 206 and the second electrode Part of 207 is located outside the semiconductor layer 201.
Accordingly, the first electrode 206 and the second electrode function as a heat radiating plate of the power generation element 103, and heat generated in the semiconductor layer 201 is radiated to the first electrode 206 and the second electrode 207.

また、本実施の形態の集光型太陽電池においては、板形状の第１電極２０６と第２電極２０７が、それぞれ、異方性導電膜１０４によって放熱板上に形成された第３電極２１０と第４電極２１１に接合していることを特徴とする。第１電極２０６と第３電極２１０の間、および、第２電極２０７と第４電極２１１の間には金属粒子が存在するので、第１電極２０６と第２電極２０７の熱は、率良く第３電極２１０と第４電極２１１を通して放熱板１０２に伝導する。この結果、半導体層２０１で発生した熱は効率良く放熱板１０２に伝わり、半導体層２０１の熱を冷却することができる。 Further, in the concentrating solar cell of the present embodiment, the plate-shaped first electrode 206 and the second electrode 207 are respectively formed of the third electrode 210 formed on the heat sink by the anisotropic conductive film 104. It is characterized by being bonded to the fourth electrode 211. Since metal particles are present between the first electrode 206 and the third electrode 210 and between the second electrode 207 and the fourth electrode 211, the heat of the first electrode 206 and the second electrode 207 is efficiently increased. The heat is conducted to the heat sink 102 through the three electrodes 210 and the fourth electrode 211. As a result, the heat generated in the semiconductor layer 201 is efficiently transmitted to the heat sink 102 and the heat of the semiconductor layer 201 can be cooled.

尚、本実施の形態で第１電極２０６は、第５電極２０２を含んで、第１の電極とし、第２電極２０７は、第６電極２０３を含んで、第２の電極としてもよい。
（実施の形態２）
本実施の形態では、実施の形態１で示した集光型太陽電池の作製方法を示す。図２、図５、図６を用いて本発明の集光型太陽電池の作製方法を説明する。 In the present embodiment, the first electrode 206 may be the first electrode including the fifth electrode 202, and the second electrode 207 may be the second electrode including the sixth electrode 203.
(Embodiment 2)
In this embodiment mode, a method for manufacturing the concentrating solar cell described in Embodiment Mode 1 will be described. The manufacturing method of the concentrating solar cell of this invention is demonstrated using FIG.2, FIG.5, FIG.6.

図５と図６は、発電素子の作製方法を示した断面模式図である。図６（ａ）、（ｂ）、（ｃ）、（ｄ）、（ｅ）は、それぞれ、図５（ａ）、（ｂ）、（ｃ）、（ｄ）、（ｅ）を半導体層５０１側から見た平面模式図である。
図５（ａ）と図６（ａ）で示すように、基板５０３に犠牲層５０２を介して半導体層５０１を形成する。基板５０３としては、例えば、厚みが４００〜６００μｍのＧａＡｓ基板を用いることができる。犠牲層５０２としては、例えば、膜厚が１０〜２００ｎｍのＡｌＡｓ膜を用いることができる。半導体層５０１としては、例えば、ｎ型のＧａＡｓ薄膜とｐ型のＧａＡｓを積層したもの、または、基板側から、ｎ型ＩｎＧａＰ膜、ｐ型ＩｎＧａＰ膜、トンネル接合膜、ｎ型ＧａＡｓ膜、ｐ型ＧａＡｓ膜、トンネル接合膜、ｎ型ＩｎＧａＡｓ膜、ｐ型ＩｎＧａＡｓ膜が積層されたものを用いることができる。また、半導体層５０１の再下部と最上面に、電極とオーミックコンタクト接続をするための抵抗率の低いコンタクト層を作製しても良い。また、光電流の再結合を防ぐために、再結合防止用の薄膜を挿入しても良い。 5 and 6 are schematic cross-sectional views illustrating a method for manufacturing a power generation element. 6A, 6 B, 6 C, 6 D, and 6 E are different from FIGS. 5A, 5 B, 5 C, 6 D, and 5 E, respectively, in the semiconductor layer 501. It is the plane schematic diagram seen from the side.
As shown in FIGS. 5A and 6A, a semiconductor layer 501 is formed on a substrate 503 with a sacrificial layer 502 interposed therebetween. As the substrate 503, for example, a GaAs substrate having a thickness of 400 to 600 μm can be used. As the sacrificial layer 502, for example, an AlAs film having a thickness of 10 to 200 nm can be used. As the semiconductor layer 501, for example, an n-type GaAs thin film and p-type GaAs are stacked, or from the substrate side, an n-type InGaP film, a p-type InGaP film, a tunnel junction film, an n-type GaAs film, and a p-type film. A laminate of a GaAs film, a tunnel junction film, an n-type InGaAs film, and a p-type InGaAs film can be used. Further, a contact layer having a low resistivity for making ohmic contact with the electrode may be formed on the lower part and the uppermost surface of the semiconductor layer 501. In order to prevent photocurrent recombination, a thin film for preventing recombination may be inserted.

次に、図５（ｂ）と図６（ｂ）で示すように、犠牲層５０２を残して、半導体層５０１をパターニングする。パターンのサイズには特に制限がないが、例えば一辺が１００〜１０００μｍの正方形にすることが望ましい。パターニングは、ウェットエッチング法またはドライエッチング法を用いることができる。なお、図ではパターニングした半導体層２０１が一個しか示されていないが、実際は、基板５０３上にパターニングした多数個の半導体層２０１が存在する。 Next, as shown in FIGS. 5B and 6B, the semiconductor layer 501 is patterned leaving the sacrificial layer 502. Although there is no restriction | limiting in particular in the size of a pattern, For example, it is desirable to make it a square whose one side is 100-1000 micrometers. For the patterning, a wet etching method or a dry etching method can be used. Note that only one patterned semiconductor layer 201 is shown in the figure, but actually, there are a large number of patterned semiconductor layers 201 on the substrate 503.

次に、図５（ｃ）と図６（ｃ）で示すように、第６電極２０３と接続用電極２０５を形成する。これらの電極は、例えば、パターニングしたレジスト膜を形成後、真空電子ビーム蒸着法でＴｉ、Ａｕ薄膜を形成した後、レジストを剥離することで形成することができる。第６電極２０３と接続用電極２０５の厚みに特に制限はないが、１０〜３００ｎｍが好ましい。 Next, as shown in FIGS. 5C and 6C, the sixth electrode 203 and the connection electrode 205 are formed. These electrodes can be formed by, for example, forming a patterned resist film, forming a Ti or Au thin film by vacuum electron beam evaporation, and then peeling the resist. Although there is no restriction | limiting in particular in the thickness of the 6th electrode 203 and the connection electrode 205, 10-300 nm is preferable.

次に、図５（ｄ）と図６（ｄ）で示すように、絶縁膜２０４を形成する。絶縁膜としては、酸化シリコン薄膜またはチッ化シリコン薄膜を用いることができる。これらの薄膜は、真空スパッタリング法またはＣＶＤ法で形成することができる。絶縁膜２０４は、ドライエッチング法によりパターニングすることが可能である。 Next, as shown in FIGS. 5D and 6D, an insulating film 204 is formed. As the insulating film, a silicon oxide thin film or a silicon nitride thin film can be used. These thin films can be formed by vacuum sputtering or CVD. The insulating film 204 can be patterned by a dry etching method.

次に、図５（ｅ）と図６（ｅ）で示すように、第１電極２０６と第２電極２０７を形成する。これらの電極は電界メッキ法により形成することができる。電極材料としてはＡｕ又はＮｉを用いることができる。 Next, as shown in FIGS. 5E and 6E, the first electrode 206 and the second electrode 207 are formed. These electrodes can be formed by electroplating. Au or Ni can be used as the electrode material.

次に、図５(ｆ)で示すように、第１電極２０６と第２電極２０７に、それぞれ、第１バンプ２０８及び第２バンプ２０９を形成する。 Next, as shown in FIG. 5F, a first bump 208 and a second bump 209 are formed on the first electrode 206 and the second electrode 207, respectively.

次に、図５(ｇ)で示すように、基板５０３と転写用基板５０４とを、ワックス５０５を用いて貼り付ける。転写用基板としては例えばガラス基板やシリコンウェーハを用いることができる。 Next, as shown in FIG. 5G, the substrate 503 and the transfer substrate 504 are attached using a wax 505. For example, a glass substrate or a silicon wafer can be used as the transfer substrate.

次に、図５(ｈ)で示すように、犠牲層５０２を残して、ウエットエッチング法またはドライエッチング法によって基板５０３のみを除去する。基板がＧａＡｓ、犠牲層がＡｌＡｓの場合は、酒石酸と過酸化水素水の混合溶液を用いることで基板のみをウェットエッチングすることが可能である。 Next, as shown in FIG. 5H, only the substrate 503 is removed by wet etching or dry etching, leaving the sacrificial layer 502. When the substrate is GaAs and the sacrificial layer is AlAs, it is possible to wet-etch only the substrate by using a mixed solution of tartaric acid and hydrogen peroxide solution.

次に、図５（ｉ）で示すように、犠牲層を除去した後、第５電極２０２を形成する。犠牲層がＡｌＡｓの場合は、フッ酸水溶液を用いて除去することができる。第５電極２０２は、図３（ｃ）で示すように、櫛型形状であることが望ましい。第５電極２０２は、犠牲層５０２を除去した後、犠牲層５０２の存在した面に、例えばＴｉとＡｕの積層膜を形成し、所定の形状のレジストのパターンを形成し、このＴｉとＡｕの積層膜をエッチング除去後、レジストを剥離することで形成することができる。 Next, as shown in FIG. 5I, after removing the sacrificial layer, the fifth electrode 202 is formed. When the sacrificial layer is AlAs, the sacrificial layer can be removed using an aqueous hydrofluoric acid solution. The fifth electrode 202 is preferably comb-shaped as shown in FIG. For the fifth electrode 202, after removing the sacrificial layer 502, a laminated film of Ti and Au, for example, is formed on the surface where the sacrificial layer 502 exists, and a resist pattern of a predetermined shape is formed. After the laminated film is removed by etching, the resist can be peeled off.

最後に、図５(ｊ)で示すように、ワックスを有機溶剤で溶解して発電素子１０３を転写用基板５０４から剥離する。 Finally, as shown in FIG. 5J, the power generation element 103 is peeled from the transfer substrate 504 by dissolving wax with an organic solvent.

次に、図２で示すように、作製した発電素子１０３を、第５電極２０２がレンズアレイの第２面１０９に向くように透明樹脂２１５を介してレンズアレイの第２面１０９に配置する。発電素子１０３をレンズアレイの第２面１０９に配置する方法に制限はないが、例えば、以下の方法を用いることができる。すなわち、最初に、レンズアレイの第２面１０９の全面にアクリル系の接着剤を塗布する。
次に、真空ピンセットで発電素子１０３をつかみ、発電素子１０３をレンズアレイの第２面１０９の所定の位置に移動し、発電素子１０３を接着剤の上に置く。最後に、接着剤を硬化して、発電素子１０３をレンズアレイの第２面１０９に固定する。
次に、発電素子を配置したレンズアレイの第２面１０９の全体に異方性導電膜１０４を形成する。異方性導電膜の形成方法には以下の二種類がある。一つ目は、Ａｕ粒子やＡｕ又はＮｉを分散した熱硬化性樹脂フィルムをレンズアレイの第２面１０９に貼り付ける方法である。この方法には、例えば、ソニ−ケミカル＆インフォメーションデバイス製の異方性導電フィルムＣＰ６９２０Ｆ３を用いることができる。二つ目は、ハンダ粒子を分散した熱硬化性樹脂内を塗布する方法である。二つ目の方法は、例えば、特許第４４３２９４９号公報、特許第４５９１３９９号公報、特開２００８−６９３１７号公報に記述されている。
次に、第１バンプ２０８と第３電極２１０、および、第２バンプ２０９と第４電極２１１が接触するように、放熱板１０２をレンズアレイ１０１の第２面１０９に押し付ける。押し付けた状態で放熱板を加熱した後、冷却する。これにより、図２で示すように、第１バンプ２０８と第３電極２１０、及び、第２バンプ２０９と第４電極２１１が電気的に接合される。 Next, as shown in FIG. 2, the produced power generation element 103 is disposed on the second surface 109 of the lens array via the transparent resin 215 so that the fifth electrode 202 faces the second surface 109 of the lens array. Although there is no restriction | limiting in the method of arrange | positioning the electric power generation element 103 in the 2nd surface 109 of a lens array, For example, the following method can be used. That is, first, an acrylic adhesive is applied to the entire second surface 109 of the lens array.
Next, the power generation element 103 is grasped with vacuum tweezers, the power generation element 103 is moved to a predetermined position on the second surface 109 of the lens array, and the power generation element 103 is placed on the adhesive. Finally, the adhesive is cured to fix the power generating element 103 to the second surface 109 of the lens array.
Next, the anisotropic conductive film 104 is formed on the entire second surface 109 of the lens array in which the power generating elements are arranged. There are the following two methods for forming the anisotropic conductive film. The first is a method of attaching a thermosetting resin film in which Au particles or Au or Ni is dispersed to the second surface 109 of the lens array. In this method, for example, an anisotropic conductive film CP6920F3 manufactured by Sony Chemical & Information Device can be used. The second is a method of applying the inside of a thermosetting resin in which solder particles are dispersed. The second method is described in, for example, Japanese Patent No. 4432949, Japanese Patent No. 459399, and Japanese Patent Application Laid-Open No. 2008-69317.
Next, the heat sink 102 is pressed against the second surface 109 of the lens array 101 so that the first bump 208 and the third electrode 210 and the second bump 209 and the fourth electrode 211 are in contact with each other. The heat sink is heated in the pressed state and then cooled. As a result, as shown in FIG. 2, the first bump 208 and the third electrode 210, and the second bump 209 and the fourth electrode 211 are electrically joined.

本実施の形態においては、第１バンプ２０８と第２バンプ２０９が、半導体層２０１の外側に位置しているので、放熱板１０２をレンズアレイ１０１に押し付けるときに、半導体層２０１には直接力がかからない。この結果、半導体層２０１が割れることがない。 In the present embodiment, since the first bump 208 and the second bump 209 are located outside the semiconductor layer 201, when the heat sink 102 is pressed against the lens array 101, direct force is applied to the semiconductor layer 201. It does not take. As a result, the semiconductor layer 201 is not broken.

以上の工程により、本発明の集光型太陽電池を作製することができる。 The concentrating solar cell of the present invention can be manufactured through the above steps.

本発明は、集光型太陽電池に利用できる。 The present invention can be used for a concentrating solar cell.

１００集光型太陽電池
１０１レンズアレイ
１０２放熱板
１０３発電素子
１０４異方性導電膜
１０５支柱
１０６台
１０７集光型太陽電池システム
１０８第１面（入射面）
１０９第２面（入射面と対向する面）
２０１半導体層（発電層）
２０２第５電極
２０３第６電極
２０４絶縁膜
２０５接続用電極（接続用金属膜）
２０６第１電極
２０７第２電極
２０８第１バンプ
２０９第２バンプ
２１０第３電極
２１１第４電極
２１２絶縁膜
２１３金属粒子
２１４熱硬化性樹脂
２１５透明樹脂
４０１共通電極
４０２外部取り出し線
５０１半導体層（発電層）
５０２犠牲層
５０３基板
５０４転写用基板
５０５ワックス
７０１太陽電池チップ
７０２レンズ
７０３下部基体 DESCRIPTION OF SYMBOLS 100 Concentration type solar cell 101 Lens array 102 Heat sink 103 Power generation element 104 Anisotropic conductive film 105 Support column 106 Stand 107 Concentration type solar cell system 108 1st surface (incident surface)
109 2nd surface (surface facing the incident surface)
201 Semiconductor layer (power generation layer)
202 5th electrode 203 6th electrode 204 Insulating film 205 Connection electrode (metal film for connection)
206 First electrode 207 Second electrode 208 First bump 209 Second bump 210 Third electrode 211 Fourth electrode 212 Insulating film 213 Metal particle 214 Thermosetting resin 215 Transparent resin 401 Common electrode 402 External lead wire 501 Semiconductor layer (power generation layer)
502 Sacrificial layer 503 Substrate 504 Transfer substrate 505 Wax 701 Solar cell chip 702 Lens 703 Lower substrate

Claims

A lens array having a first surface serving as a light incident surface and a flat second surface facing the light incident surface, wherein a focal point exists in the vicinity of the second surface, and the second surface of the lens array A concentrating type comprising a plurality of power generation elements that are in contact with each other through a transparent resin in the vicinity of the focal point existing inside, and a heat radiating plate disposed on the side opposite to the second surface with respect to the power generation elements A solar cell,
The power generating element includes a plate-shaped semiconductor layer having a first surface for irradiating light and a second surface facing the first surface, a fifth electrode formed on the first surface, and a second surface on the second surface. The formed sixth electrode, the plate-shaped first electrode that is electrically joined to the fifth electrode, and the plate-shaped second electrode that is electrically joined to the sixth electrode,
A thickness of the first electrode and the second electrode is greater than a thickness of the semiconductor layer;
A part of the first electrode and a part of the second electrode are present outside the semiconductor layer;
The first surface of the semiconductor layer faces the second surface of the lens;
The first electrode region located outside the semiconductor layer and the third electrode formed on the heat sink, and the second electrode region located outside the semiconductor layer and the fourth electrode formed on the heat sink. A concentrating solar cell, wherein the electrodes are electrically joined with an anisotropic conductive resin.

A lens array (101) having a light incident surface (108) and condensing light incident from the light incident surface;
A power generating element (103) that receives light collected by the lens array and generates electricity;
A concentrating solar cell having a heat sink (102) disposed on the side facing the lens array with respect to the power generation element,
The power generating element is:
A semiconductor layer (201) having a first surface (201a) on which light is incident and a second surface (201b) facing the first surface;
A fifth electrode (202) formed on the first surface;
A sixth electrode (203) formed on the second surface;
A first electrode (206) electrically connected to the fifth electrode, having a thickness larger than the thickness of the semiconductor layer, and having an end protruding to the outer peripheral side of the semiconductor layer;
A second electrode (207) electrically connected to the sixth electrode, having a thickness larger than the thickness of the semiconductor layer, and having an end protruding to the outer peripheral side of the semiconductor layer;
An end region (206c) of the first electrode protruding to the outer peripheral side of the semiconductor layer and a third electrode (210) formed on the heat sink;
And the anisotropic conductive resin (Electric conductive resin which electrically joins the edge part area | region (207c) of the 2nd electrode which protruded to the outer peripheral side of the said semiconductor layer, and the 4th electrode (211) formed on the heat sink, respectively. 104)
The said lens array and the said heat sink are the concentrating solar cells joined by the anisotropic conductive film.

The first surface (206d) of the end portion of the first electrode, the first surface (207d) of the end portion of the second electrode, and the light irradiation surface (201a) of the semiconductor layer are positioned on substantially the same plane. The concentrating solar cell according to claim 2, wherein a lens array is provided on the first surface of the end portion, the first surface of the end portion of the second electrode, and the light irradiation surface of the semiconductor layer via a transparent resin (215).

The concentrating solar cell according to claim 2, wherein the anisotropic conductive film is made of a thermosetting resin and metal particles.

The concentrating solar cell according to claim 2, wherein the metal particles are gold particles or resin particles whose surfaces are coated with gold.

The concentrating solar cell according to claim 2, wherein the metal particles are solder particles.

A lens array that has a light incident surface and collects light incident from the light incident surface;
A power generating element that receives light collected by the lens array and generates electricity;
A concentrating solar cell having a heat radiating plate disposed on the side facing the lens array with respect to the power generation element,
The power generating element is:
Including a power generation layer, a first electrode, a second electrode, a first bump, a second bump,
The power generation layer is formed by laminating an n-type semiconductor layer and a p-type semiconductor layer,
In transmission plan view, the first bump does not overlap the power generation layer,
The n-type semiconductor layer is electrically connected to the first bump via the first electrode;
In transmission plan view, the second bump does not overlap the power generation layer,
The p-type semiconductor layer is electrically connected to the second bump via the second electrode;
The thickness of the first electrode and the second electrode is larger than the thickness of the power generation layer,
The first bump is electrically bonded to an electrode formed on a heat sink via an anisotropic conductive film,
The second bump is a concentrating solar cell in which the second bump is electrically joined to an electrode formed on the heat sink via an insulating film via an anisotropic conductive film.

A lens array that has a light incident surface and collects light incident from the light incident surface;
A power generating element that receives light collected by the lens array and generates electricity;
A concentrating solar cell having a heat radiating plate disposed on the side facing the lens array with respect to the power generation element,
The power generating element is:
Including a power generation layer, a first electrode, a second electrode, a first bump, a second bump,
The power generation layer is formed by laminating an n-type semiconductor layer and a p-type semiconductor layer,
In transmission plan view, the first bump does not overlap the power generation layer,
The p-type semiconductor layer is electrically connected to the first bump via the first electrode;
In transmission plan view, the second bump does not overlap the power generation layer,
The n-type semiconductor layer is electrically connected to the second bump via the second electrode;
The thickness of the first electrode and the second electrode is larger than the thickness of the power generation layer,
The first bump is electrically bonded to an electrode formed on a heat sink via an anisotropic conductive film,
The second bump is a concentrating solar cell in which the second bump is electrically joined to an electrode formed on the heat sink via an insulating film via an anisotropic conductive film.

The first electrode includes a fifth electrode formed on the first surface on the light incident surface side in the semiconductor layer, and an electrode electrically connected to the fifth electrode,
The condensing type according to claim 7 or 8, wherein the second electrode includes a sixth electrode formed on a second surface facing the first surface, and an electrode electrically connected to the sixth electrode. Solar cell.