JP2011035150A - Photoelectric converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a photoelectric converter of a mechanical stack system, by which high generation efficiency equivalent to that of a lamination type thin-film photoelectric converter is provided by a simple configuration. <P>SOLUTION: A first photoelectric conversion module in which plural first photoelectric conversion elements each forming in order a first substrate side electrode and a first photoelectric conversion layer on one surface of a first substrate with a translucency and an insulation performance, are formed; and a second photoelectric conversion module in which plural second photoelectric conversion elements each forming in order a second substrate side electrode and a second photoelectric conversion layer on one surface of a second substrate, are formed, are stuck while the first and second photoelectric conversion elements face inward. Plural photoelectric conversion element pairs constituted by electrically connecting in series the first and second photoelectric conversion elements across a transparent conductive layer, are provided. In the adjacent photoelectric conversion element pairs, the adjacent photoelectric conversion element pairs are electrically connected in series by electrically connecting one first substrate side electrode and the other second substrate side electrode with a connecting member. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion device, and more particularly to a mechanical stack type photoelectric conversion device in which two types of photoelectric conversion elements respectively formed on different substrates are arranged to face each other.

  In a conventional stacked thin film silicon photoelectric conversion device, for example, a transparent electrode layer, a photoelectric conversion layer containing silicon, and a back electrode are stacked on a light transmitting insulating substrate to form an element. In such a stacked thin film silicon photoelectric conversion device, a plurality of photoelectric conversion layers having different light absorption characteristics are stacked in order to improve photoelectric conversion efficiency. Moreover, in order to utilize sunlight effectively, the fine concavo-convex structure is provided on the surface of the transmissive electrode layer. This fine concavo-convex structure improves the absorption of sunlight into the photoelectric conversion layer. However, sunlight has various wavelengths, and the optimal uneven structure size varies depending on the wavelength, but it is difficult to provide various fine uneven structures.

  Therefore, in order to employ an optimum uneven structure for each photoelectric conversion layer, a mechanical stack type thin film photoelectric conversion device in which photoelectric conversion modules are stacked is used. In the mechanical stack type thin film photoelectric conversion device, the stacked photoelectric conversion modules are formed on independent substrates. That is, in a conventional mechanical stack type thin film photoelectric conversion module, for example, a photoelectric conversion module in which a transparent electrode layer and a photoelectric conversion layer made of a thin film semiconductor are formed on a transparent substrate, and a metal electrode on the substrate The photoelectric conversion module on which the photoelectric conversion layer formed of the layer and the thin film semiconductor is formed so as to face each other so that the surface on which the photoelectric conversion layer is not formed is arranged on the outside, and the output is individually taken out It is configured.

  Further, in each photoelectric conversion module, a plurality of photoelectric conversion elements are processed in a stripe shape, and adjacent photoelectric conversion elements are electrically connected in series and arranged adjacent to each other with a predetermined distance therebetween. The photoelectric conversion layers are electrically separated.

  In addition, in the stacked type thin film photoelectric conversion device of the mechanical stack type, in order to improve efficiency, the band gap of the photoelectric conversion layer formed on the substrate on the light incident side is changed to that of the photoelectric conversion layer formed on the other substrate. Make it wider than the band gap. Thereby, light of high energy (short wavelength) is absorbed by the photoelectric conversion element formed on the substrate on the light incident side, and light transmitted through the photoelectric conversion element is absorbed by the photoelectric conversion element formed on the other substrate. Therefore, light can be used efficiently. However, in such a mechanical stack type thin film photoelectric conversion device, the open-circuit voltages have different values because the band gaps of the photoelectric conversion layers formed on the respective substrates are different.

  As such a mechanical stack type thin film photoelectric conversion device, for example, the space between the thin film solar cell unit cells provided on two opposing substrates is blocked from the outside, and electric power is taken out from each substrate by separate wiring. A structure has been proposed in which the optimum operating voltage of thin-film solar cell units provided on two opposing substrates is made equal and connected in parallel internally to extract power. In addition, the number of thin-film solar cell units connected in series in each substrate is adjusted in order to equalize the optimum operating voltage of both substrates, and both substrates are held at intervals by a peripheral frame or sealing glass (for example, Patent Document 1).

Japanese Patent Laid-Open No. 60-30163

  However, according to the above-described conventional technology, in the configuration in which power is extracted from both substrates by separate wiring, a plurality of output wirings having different voltages and currents are mixed, and the configuration of the power extraction unit becomes complicated. is there. In addition, in the configuration in which the optimum operating voltage between the two substrates is matched and connected in parallel inside, the take-out part is simple, but a voltage difference arises due to the difference in temperature dependence of the voltage in the thin film solar cell unit cell of both substrates. Thus, there is a problem that the current generated in the thin film solar cell unit cell on one substrate flows to the other.

  The present invention has been made in view of the above, and an object thereof is to obtain a mechanical stack type photoelectric conversion device capable of realizing high power generation efficiency similar to that of a stacked thin film photoelectric conversion device with a simple configuration. To do.

  In order to solve the above-described problems and achieve the object, a photoelectric conversion device according to the present invention includes a first substrate-side electrode, a first photoelectric conversion layer, and a light-transmitting and insulating first substrate. A first photoelectric conversion module in which a plurality of first photoelectric conversion elements are formed in sequence, and a second photoelectric conversion in which a second substrate side electrode and a second photoelectric conversion layer are sequentially formed on one surface of a second substrate. A second photoelectric conversion module in which a plurality of elements are formed, and the first photoelectric conversion element and the second photoelectric conversion element are bonded to each other, and the first photoelectric conversion element disposed at an opposite position and the first photoelectric conversion element A plurality of photoelectric conversion element pairs configured such that the second photoelectric conversion elements are electrically connected in series with the transparent conductive layer interposed therebetween, and one of the first substrate side electrode and the other in the adjacent photoelectric conversion element pair The second substrate side electrode of the Said photoelectric conversion elements adjacent pairs by being electrically connected are electrically connected in series, characterized by.

  According to the present invention, a pair of photoelectric conversion elements that are configured by electrically connecting a first photoelectric conversion element and a second photoelectric conversion element that are disposed at opposing positions are electrically connected in series. As a result, the photoelectric conversion element operates at the optimum operating point. Thereby, there is an effect that a mechanical stack type photoelectric conversion device having high power generation efficiency similar to that of the stacked thin film photoelectric conversion device can be obtained with a simple configuration.

1-1 is a plan view showing a schematic configuration of a mechanical stack type thin film photoelectric conversion device according to Embodiment 1 of the present invention. FIG. FIGS. 1-2 is principal part sectional drawing for demonstrating the cross-section of the mechanical stack type thin film photoelectric conversion apparatus concerning Embodiment 1 of this invention. FIGS. FIG. 2 is an equivalent circuit diagram of the mechanical stack type thin film photoelectric conversion device according to the first embodiment of the present invention. FIG. 3 is an equivalent circuit diagram of a conventional mechanical stack type photoelectric conversion device. FIG. 4 is an equivalent circuit diagram of a conventional mechanical stack type photoelectric conversion device. FIGS. 5-1 is principal part sectional drawing for demonstrating the manufacturing process of the thin film photoelectric conversion apparatus of the mechanical stack system concerning Embodiment 1 of this invention. FIGS. FIGS. 5-2 is principal part sectional drawing for demonstrating the manufacturing process of the thin film photoelectric conversion apparatus of the mechanical stack type concerning Embodiment 1 of this invention. FIGS. FIGS. 5-3 is principal part sectional drawing for demonstrating the manufacturing process of the thin film photoelectric conversion apparatus of the mechanical stack system concerning Embodiment 1 of this invention. FIGS. 5-4 is principal part sectional drawing for demonstrating the manufacturing process of the thin film photoelectric conversion apparatus of the mechanical stack | stuck system concerning Embodiment 1 of this invention. FIG. 6 is a perspective view showing a schematic configuration of a mechanical stack type photoelectric conversion apparatus according to Embodiment 2 of the present invention. FIG. 7 is an exploded perspective view showing a state in which the opposing photoelectric conversion modules in the mechanical stack type photoelectric conversion apparatus according to the second embodiment of the present invention are disassembled. FIG. 8 is an exploded perspective view showing a state in which each layer of the photoelectric conversion module in the mechanical stack type photoelectric conversion apparatus according to the second embodiment of the present invention is disassembled.

  Embodiments of a photoelectric conversion device according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings.

Embodiment 1 FIG.
1-1 is a plan view showing a schematic configuration of a mechanical stack type thin film photoelectric conversion device 1 according to a first embodiment of the present invention. 1-2 is a diagram for explaining a cross-sectional structure of the thin-film photoelectric conversion device 1, and is a main-portion cross-sectional view in the direction of line AA ′ in FIG. 1-1.

  The mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment includes a first photoelectric conversion module 2 and a second photoelectric conversion module 7 which are thin film photoelectric conversion modules each including a plurality of photoelectric conversion elements. Has a configuration in which the photoelectric conversion elements are bonded to each other, and light enters from the substrate side of the first photoelectric conversion module 2.

  The first photoelectric conversion module 2 includes a plurality of photoelectric conversion elements 3a and 3b (hereinafter sometimes collectively referred to as photoelectric conversion elements 3) which are first photoelectric conversion elements. The photoelectric conversion element 3 has a texture structure (not shown) on the surface opposite to the light-transmitting insulating substrate 4 on the light-transmitting insulating substrate 4 that is the first substrate. The transparent electrode layer 5 which is a first substrate side electrode patterned in a stripe shape extending in a direction substantially parallel to the short direction, and the short side of the translucent insulating substrate 4 having substantially the same shape and arrangement as the transparent electrode layer 5 A thin film semiconductor layer 6, which is a first thin film semiconductor layer patterned in a stripe shape extending in a direction substantially parallel to the direction, is sequentially stacked. In the first photoelectric conversion module 2, the adjacent photoelectric conversion elements 3 are not electrically connected to each other.

  In addition, in FIG. 1-2, although two adjacent photoelectric conversion elements 3a and 3b are shown among the 1st photoelectric conversion modules 2 for convenience, the quantity of the photoelectric conversion elements 3 with which the 1st photoelectric conversion module 2 is provided. However, the present invention is not limited to this, and a large number of photoelectric conversion elements 3 are formed on the translucent insulating substrate 4.

  In the mechanical stack type thin film photoelectric conversion device 1, since light is incident from the light-transmissive insulating substrate 4 side of the first photoelectric conversion module 2, the light-transmissive insulating substrate 4 is made of a light-transmitting material such as glass or transparent resin. A plate-like member or a sheet-like member made of an insulating material having the above is used.

For the transparent electrode layer 5, a transparent conductive oxide (TCO) such as tin oxide (SnO ₂ ), zinc oxide (ZnO), indium oxide (In ₂ O ₃ ), or the like is used as a transparent conductive film having optical transparency. It is formed using a method such as CVD (Chemical Vapor Deposition), sputtering, or vapor deposition. Further, the transparent electrode layer 5 has a surface texture structure (not shown) in which a concavo-convex shape is formed on the surface opposite to the translucent insulating substrate 4. The texture structure has a function of scattering incident sunlight, absorbing incident light more efficiently by the first photoelectric conversion module 2 and the second photoelectric conversion module 7, and improving light use efficiency. The texture structure of the transparent electrode layer 5 is an uneven structure suitable for light absorption for the thin film semiconductor layer 6 of the first photoelectric conversion module 2. Note that an undercoat layer made of silicon oxide (SiO ₂ ) or the like may be formed on the translucent insulating substrate 4 as a blocking layer for impurities from the translucent insulating substrate 4 as necessary.

  The thin film semiconductor layer 6 is disposed behind the transparent electrode layer 5 as viewed from the light incident side, has a P-I-N structure, and is configured by laminating one or more thin film semiconductor layers that generate power by incident light. The The thin film semiconductor layer 6 includes a P-type semiconductor layer that is a first conductive type semiconductor layer from the translucent insulating substrate 4 side, an I-type semiconductor layer that is a substantially intrinsic photoelectric conversion layer and is a second conductive type semiconductor layer, And a PIN junction composed of an N-type semiconductor layer which is a third conductivity type semiconductor layer. In the present embodiment, the thin film semiconductor layer 6 includes, in order from the translucent insulating substrate 4 side, a P-type hydrogenated amorphous silicon carbide (a-SiC: H) layer, which is a first conductive type semiconductor layer, and a second conductive type. P-I- consisting of an I-type hydrogenated amorphous silicon (a-Si: H) layer as a type semiconductor layer and an N-type hydrogenated amorphous silicon (a-Si: H) layer as a third conductivity type semiconductor layer N junction is formed.

  The thin film semiconductor layer 6 is a P-type hydrogenated amorphous silicon carbide (a-SiC: H) layer or a second conductivity type semiconductor layer, which is a first conductivity type semiconductor layer, from the translucent insulating substrate 4 side. I-type hydrogenated amorphous silicon (a-Si: H) layer, N-type hydrogenated microcrystalline silicon (μc-Si: H) layer as a third conductivity type semiconductor layer, P as a first conductivity-type semiconductor layer Type hydrogenated microcrystalline silicon (μc-Si: H) layer, second conductivity type semiconductor layer I type hydrogenated microcrystalline silicon (μc-Si: H) layer, third conductivity type semiconductor layer N Alternatively, a two-stage PIN junction composed of a hydrogenated microcrystalline silicon (μc-Si: H) layer may be used.

Further, in the case where the thin film semiconductor layer 6 is formed by laminating a plurality of thin film semiconductor layers as in the two-stage P-I-N junction described above, an oxide microcrystal is formed between the P-I-N junctions. Inserting an intermediate layer such as silicon (μc-SiO _x (X = 0 to 2)) or aluminum-added zinc oxide (ZnO: Al) to improve electrical and optical connection between P-I-N junctions May be.

  The second photoelectric conversion module 7 includes a plurality of photoelectric conversion elements 8a and 8b (hereinafter may be collectively referred to as photoelectric conversion elements 8), which are second photoelectric conversion elements. The photoelectric conversion element 8 has a textured structure on the surface opposite to the conductive metal substrate 9 on the conductive metal substrate 9 which is an elongated second substrate having a concavo-convex shape on the surface, and is short of the translucent insulating substrate 4. The back transparent electrode layer 10, which is a second substrate side electrode patterned in a stripe shape extending in a direction substantially parallel to the hand direction, has the same shape and arrangement as the back transparent electrode layer 10, and is short of the translucent insulating substrate 4. A thin film semiconductor layer 11 that is a second thin film semiconductor layer patterned in a stripe shape extending in a direction substantially parallel to the hand direction is sequentially stacked. In the second photoelectric conversion module 7, the adjacent photoelectric conversion elements 8 are not electrically connected.

  In addition, in FIG. 1-2, although 2 adjacent photoelectric conversion elements 8a and 8b are shown among the 2nd photoelectric conversion modules 7 for convenience, the quantity of the photoelectric conversion elements 8 with which the 2nd photoelectric conversion module 7 is provided. Is not limited to this, and a large number of photoelectric conversion elements 8 are formed on the conductive metal substrate 9.

  As the conductive metal substrate 9, for example, a metal substrate such as silver (Ag) or aluminum (Al) is used. The conductive metal substrate 9 has a concavo-convex structure larger (gradual) than the texture structure included in the transparent electrode layer 5 on the surface on the back surface transparent electrode layer 10 side.

The back transparent electrode layer 10 uses a transparent conductive oxide (TCO) such as tin oxide (SnO ₂ ), zinc oxide (ZnO), indium oxide (In ₂ O ₃ ), for example, as a transparent conductive film having optical transparency. And formed using a method such as CVD, sputtering, or vapor deposition. Moreover, an undercoat layer made of silicon oxide (SiO ₂ ) or the like may be formed on the conductive metal substrate 9 as a blocking layer for impurities from the conductive metal substrate 9 as necessary. Moreover, the back surface transparent electrode layer 10 has a shape along the surface shape of the conductive metal substrate 9 and has a texture structure having a concavo-convex structure larger (gradual) than the texture structure included in the transparent electrode layer 5 on both main surfaces. . This texture structure is an uneven structure suitable for light absorption for the thin film semiconductor layer 11 of the second photoelectric conversion module 7.

  The thin film semiconductor layer 11 is disposed in front of the back transparent electrode layer 10 as viewed from the light incident side, has a PIN structure, and is configured by laminating one or more thin film semiconductor layers that generate power by incident light. Is done. The thin film semiconductor layer 11 includes, from the back transparent electrode layer 10 side, an N-type semiconductor layer that is a third conductive semiconductor layer, an I-type semiconductor layer that is a substantially intrinsic photoelectric conversion layer and is a second conductive semiconductor layer, and a first conductive layer. An N-I-P junction composed of a P-type semiconductor layer which is a one-conductivity-type semiconductor layer is formed. In the present embodiment, the thin film semiconductor layer 11 includes, in order from the back transparent electrode layer 10 side, an N-type hydrogenated microcrystalline silicon (μc-Si: H) layer, which is a third conductivity type semiconductor layer, and a second conductivity type. An N-type consisting of an I-type hydrogenated microcrystalline silicon (μc-Si: H) layer as a semiconductor layer and a P-type hydrogenated microcrystalline silicon (μc-Si: H) layer as a first conductivity type semiconductor layer. An IP junction is formed.

  Further, the thin film semiconductor layer 11 is an N-type hydrogenated microcrystalline silicon (μc-Si: H) layer, which is a third conductivity type semiconductor layer, and an I, which is a second conductivity type semiconductor layer, from the back transparent electrode layer 10 side. Type hydrogenated microcrystalline silicon (μc-Si: H) layer, P-type hydrogenated microcrystalline silicon (μc-Si: H) layer which is the first conductivity type semiconductor layer, N which is the third conductivity type semiconductor layer Type hydrogenated microcrystalline silicon (μc-Si: H) layer, second conductivity type semiconductor layer I type hydrogenated amorphous silicon germanium (a-SiGe: H) layer, first conductivity type semiconductor layer P Alternatively, a two-stage N-I-P junction structure including a hydrogenated microcrystalline silicon (μc-Si: H) layer may be used.

Further, in the case where the thin film semiconductor layer 11 is configured by laminating a plurality of thin film semiconductor layers as in the above-described two-stage NIP junction, an oxide microcrystal is formed between the NIP junctions. Inserting an intermediate layer such as silicon (μc-SiO _x (X = 0-2)) or aluminum-added zinc oxide (ZnO: Al) to improve the electrical and optical connection between NIP junctions May be.

  As a combination of the first photoelectric conversion module 2 and the second photoelectric conversion module 7, for example, (1) 1-stage pin junction-1 stage nip junction, (2) 2-stage, Pin junction-1 stage nip junction, (3) 1 stage pin junction-2 stage nip junction, (4) 2 stage pin junction-2 stage nip junction.

  Further, the width in the longitudinal direction of the translucent insulating substrate 4 in the photoelectric conversion element 3 (the width in the direction of the line AA ′ in FIG. 1-1) and the translucent insulating substrate 4 in the photoelectric conversion element 8. The width in the longitudinal direction (width in the direction of the line segment AA ′ in FIG. 1-1) is substantially the same, and the photoelectric conversion element 3 and the photoelectric conversion element 8 are opposed to each other in the thin film photoelectric conversion device 1. The photoelectric conversion element 3 and the photoelectric conversion element 8 constitute a pair. That is, in FIG. 1-2, the photoelectric conversion element 3a and the photoelectric conversion element 8a are arranged at positions facing each other to constitute a photoelectric conversion element pair, and the photoelectric conversion element 3b and the photoelectric conversion element 8b are opposed to each other. The photoelectric conversion element pair is configured by being arranged at a position. This photoelectric conversion element pair can be regarded as a new photoelectric conversion element. Adjacent photoelectric conversion element pairs are separated by an insulating resin 13.

  Also, as shown in FIG. 1B, in the photoelectric conversion element 3 and the photoelectric conversion element 8 that face each other, the thin film semiconductor layer 6 and the thin film semiconductor layer 11 are disposed between the thin film semiconductor layer 6 and the thin film semiconductor layer 11. The transparent conductive layer 12 is electrically connected and bonded. The transparent conductive layer 12 is made of, for example, a metal paste or an anisotropic conductive film, and has both transparency and conductivity. Such a transparent conductive layer 12 is applied and fired with a metal alkoxide solution obtained by mixing a metal oxide such as zinc oxide or tin oxide with an organic solvent such as ethanol, 2-methoxyethanol or monoethanolamine. Can be obtained. The transparent conductive layer 12 can be replaced with a resin or sheet having both transparency and conductivity. Further, the transparent conductive layer 12 may be one in which metal particles or conductive oxide particles are dispersed in a transparent resin.

  With such a configuration, the opposing photoelectric conversion element 3 and the photoelectric conversion element 8 are electrically directly connected, and an element configuration similar to that of the stacked thin film photoelectric conversion element formed on the same substrate is obtained. All the photoelectric conversion element pairs of the thin film photoelectric conversion device 1 have substantially the same characteristics. And in the thin film photoelectric conversion apparatus 1, a power fall can be prevented compared with parallel connection. Moreover, since the elements of the first photoelectric conversion module 2 and the second photoelectric conversion module 7 are connected in series, compared with the case where the first photoelectric conversion module 2 and the second photoelectric conversion module 7 are paralleled. The voltage can be easily increased, and loss due to wiring resistance can be reduced.

  In the adjacent photoelectric conversion element pair, for example, the conductive metal substrate 9 of the photoelectric conversion element 8a and the transparent electrode layer 5 of the photoelectric conversion element 3b constituting the adjacent pair are electrically connected by the metal substrate 14 as a connecting member. Connected. With such a configuration, adjacent photoelectric conversion element pairs are electrically connected directly, and an element configuration similar to that in a case where stacked thin film photoelectric conversion elements formed on the same substrate are connected in series is obtained.

  Connection by the connection member of the first embodiment will be described in more detail. In the first photoelectric conversion module 2, the transparent electrode layer 5 on the translucent insulating substrate 4 has a region protruding from below the thin film semiconductor layer 6, and this portion serves as a connection portion. This connection portion is in the separation groove of the thin film semiconductor layer 6. One of the metal substrates 14 is electrically connected to the back transparent electrode layer 10 that is the second substrate side electrode through the conductive metal substrate 9. The other of the metal substrates 14 extends from the conductive metal substrate 9 side toward the connection portion of the transparent electrode layer 5 in the separation groove, and adjacent photoelectric conversion element pairs are electrically connected in series. Since the metal substrate 14 has a structure that extends and is connected to the substrate substantially perpendicularly, it is possible to form a relatively narrow separation groove, and the area of the separation groove that does not contribute to power generation can be reduced. The metal substrate 14 is disposed so as not to contact the conductive metal substrate 9 and the second substrate side electrode of the adjacent photoelectric conversion element pair. In addition, about the above specific connection structure, it can change variously including the shape and connection position of a member. The metal substrate 14 may not be directly in contact with the transparent electrode layer 5 but may be connected via another conductive member formed on the transparent electrode layer 5.

  FIG. 2 is an equivalent circuit diagram of the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment. As shown in FIG. 2, in the thin film photoelectric conversion device 1, all the photoelectric conversion elements 3 and the photoelectric conversion elements 8 are alternately connected in series, and the photoelectric conversion elements 3 are the same as in the stacked thin film photoelectric conversion device. , 8 operate at the optimum operating point, and the power generation efficiency is improved. Thereby, in the thin film photoelectric conversion apparatus 1, the photoelectric conversion efficiency equivalent to a lamination type thin film photoelectric conversion apparatus is realizable.

  3 and 4 are equivalent circuit diagrams of a conventional mechanical stack type photoelectric conversion device. The photoelectric conversion device illustrated in FIGS. 3 and 4 includes a first photoelectric conversion module 211 in which a plurality of photoelectric conversion elements 201 are formed and a second photoelectric conversion module 212 in which a plurality of photoelectric conversion elements 202 are formed. This is a mechanical stack type photoelectric conversion device configured by arranging elements facing each other. Generally, the power generation characteristics of the photoelectric conversion element 201 and the photoelectric conversion element 202 in a mechanical stack type photoelectric conversion apparatus are different. For this reason, in the conventional mechanical stack type photoelectric conversion device, as shown in FIG. 3 and FIG. 4, the output is independently taken out from each module, or the number of series stages of photoelectric conversion elements is set so that the output voltages are almost equal. The method of changing is adopted. FIG. 3 shows a mechanical stack type photoelectric conversion device that takes out outputs from each module independently. FIG. 4 shows a mechanical stack type photoelectric conversion device in which the number of series stages of photoelectric conversion elements is changed for each module so that the output voltages are substantially equal.

  However, in the case of a method of independently taking out the output from each module, an output taking-out unit is required for each module, and a plurality of output wirings having different voltages and currents are mixed, resulting in an increase in member cost. The structure becomes complicated. Also, in the case of a system in which the optimum operating voltage between both boards is matched and connected in parallel internally, and the number of series stages of photoelectric conversion elements is changed for each module, the voltage difference is due to the difference in temperature dependence of the voltage of both boards. As a result, the current generated by one substrate flows to the other. In addition, since the number of series-connected photoelectric conversion elements formed in the same size module is different between the two modules, the performance equivalent to that of the stacked thin film photoelectric conversion apparatus having the same number of photoelectric conversion elements. This cannot be realized, and the power generation efficiency of the entire stack module is reduced.

  On the other hand, in the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment, the opposing photoelectric conversion element 3 and the photoelectric conversion element 8 are electrically connected, and adjacent to the photoelectric conversion element 3. All the photoelectric conversion elements 3 and the photoelectric conversion elements 8 are alternately connected in series by being electrically connected to the photoelectric conversion elements 8 constituting the pair of photoelectric conversion elements to be equivalent to the stacked thin film photoelectric conversion device. The photoelectric conversion elements 3 and 8 operate at the optimum operating point, and the power generation efficiency is improved.

  Next, a method for manufacturing the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment will be described with reference to FIGS. 5A to 5D are cross-sectional views of relevant parts for explaining the manufacturing process of the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment.

First, the first photoelectric conversion module 2 is produced. First, for example, a flat glass substrate is prepared as the translucent insulating substrate 4. On one surface side of the translucent insulating substrate 4, tin oxide (SnO ₂ ), zinc oxide (having an uneven texture structure on the surface) A transparent electrode layer 5 made of a transparent conductive oxide (TCO) such as ZnO) or indium oxide (In ₂ O ₃ ) is formed by a method such as a CVD method, a sputtering method, or a vapor deposition method.

  Next, a thin film semiconductor layer 6 for photoelectric conversion made of, for example, amorphous silicon is formed on the transparent electrode layer 5 by a plasma CVD method or the like, and the first photoelectric conversion module 2 ′ before the photoelectric conversion element is separated. Get. Here, the thin-film semiconductor layer 6 includes a p-type hydrogenated amorphous silicon carbide (a-SiC: H) layer and a second conductive semiconductor layer, which are first conductive semiconductor layers, from the translucent insulating substrate 4 side. An i-type hydrogenated amorphous silicon (a-Si: H) layer and an n-type hydrogenated amorphous silicon (a-Si: H) layer which is a third conductivity type semiconductor layer are sequentially formed (FIG. 5-1). Thereafter, the first photoelectric conversion module 2 is obtained by forming a separation groove in the first photoelectric conversion module 2 ′ before element separation, for example, by laser scribing and dividing it into a plurality of photoelectric conversion elements 3 (FIG. Not shown). When forming the separation groove, the transparent electrode layer 5 is removed from the lower part of the thin film semiconductor layer 6 by using the process of removing the transparent electrode layer 5 and the process of removing the thin film semiconductor layer 6 while leaving the transparent electrode layer 5. An area where the portion protrudes is formed in advance. As a result, a part of the transparent electrode layer 5 serving as a connection portion is exposed at the bottom of the separation groove of the thin film semiconductor layer 6.

  Next, the second photoelectric conversion module 7 is produced. First, as the conductive metal substrate 9, for example, a metal substrate that reflects light such as silver (Ag) or aluminum (Al) having an uneven texture structure on one side is prepared. Here, the texture structure is a texture structure having a concavo-convex structure larger (gradual) than the texture structure on the surface of the transparent electrode layer 5.

Next, a back transparent electrode made of a transparent conductive oxide (TCO) such as tin oxide (SnO ₂ ), zinc oxide (ZnO), or indium oxide (In ₂ O ₃ ) is formed on one surface side of the conductive metal substrate 9. Layer 10 is formed using a method such as CVD, sputtering, or vapor deposition. Moreover, an undercoat layer made of silicon oxide (SiO ₂ ) or the like may be formed on the conductive metal substrate 9 as a blocking layer for impurities from the conductive metal substrate 9 as necessary.

  Next, a thin film semiconductor layer 11 for photoelectric conversion made of, for example, hydrogenated microcrystalline silicon is formed on the back transparent electrode layer 10 by plasma CVD or the like, and the second photoelectric before the photoelectric conversion element is separated. A conversion module 7 ′ is obtained. Here, from the back transparent electrode layer 10 side as the thin film semiconductor layer 11, an n-type hydrogenated microcrystalline silicon (μc-Si: H) layer that is a third conductivity type semiconductor layer, and i that is a second conductivity type semiconductor layer. Type hydrogenated microcrystalline silicon (.mu.c-Si: H) layer and p-type hydrogenated microcrystalline silicon (.mu.c-Si: H) layer, which is a first conductivity type semiconductor layer, are sequentially formed (FIG. 5-2). .

  Thereafter, the second photoelectric conversion module 7 is obtained by dividing the second photoelectric conversion module 7 ′ before element separation into a plurality of photoelectric conversion elements 8 by laser scribing, for example (not shown). Here, the second photoelectric conversion module 7 is divided for each conductive metal substrate 9.

  Next, on the entire surface of the thin film semiconductor layer 6 of the first photoelectric conversion module 2 and on the entire surface of the thin film semiconductor layer 11 of the second photoelectric conversion module 7, for example, a metal oxide such as zinc oxide or tin oxide and A metal alkoxide solution mixed with an organic solvent such as ethanol, 2-methoxyethanol, or monoethanolamine is applied and pre-baked. Then, the application surfaces of the first photoelectric conversion module 2 and the second photoelectric conversion module 7 are opposed to each other so that the photoelectric conversion element 3 and the photoelectric conversion element 8 forming the photoelectric conversion element pair face each other. After the pressure bonding, the main baking is performed. Thereby, the transparent conductive layer 12 is formed between the thin film semiconductor layer 6 and the thin film semiconductor layer 11 (FIG. 5-3). The transparent conductive layer 12 is not desirable because it causes a short circuit that protrudes from the thin film semiconductor layer 6 or the thin film semiconductor layer 11 to the separation groove side. When the transparent conductive layer 12 is formed by applying the raw material as described above, a method such as screen printing may be used at the time of application. The application shape of the screen printing is preferably the same shape as the surface of the thin film semiconductor layer or a slightly smaller pattern.

  Here, the thin film semiconductor layer 6 of the opposing first photoelectric conversion module 2 and the thin film semiconductor layer 11 of the second photoelectric conversion module 7 are transparent between the thin film semiconductor layer 6 and the thin film semiconductor layer 11. The conductive layer 12 is electrically connected. The transparent conductive layer 12 may be replaced with a resin or sheet having both transparency and conductivity.

  After that, the insulating resin 13 is disposed along the side wall in the separation groove, and the metal substrate 14 is embedded between the insulating resin 13 along the extending direction of the separation groove (FIG. 5-4). By the metal substrate 14, the conductive metal substrate 9 of the photoelectric conversion element 8 and the transparent electrode layer 5 of the photoelectric conversion element 3 constituting an adjacent pair are electrically connected. Thereby, the mechanical stack type thin film photoelectric conversion device 1 in which the first photoelectric conversion module 2 and the second photoelectric conversion module 7 as shown in FIGS. 1-1 and 1-2 are bonded together is obtained. Thereafter, an output extraction section (not shown) is formed at each of the photoelectric conversion elements at both ends among the plurality of photoelectric conversion elements connected in series.

  As described above, in the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment, the opposing photoelectric conversion element pairs are electrically connected, and the photoelectric conversion elements 3 and the photoelectric elements constituting the adjacent pairs are electrically connected. When the conversion element 8 is electrically connected, all the photoelectric conversion elements 3 and the photoelectric conversion elements 8 are alternately connected in series as in the equivalent circuit shown in FIG. Thereby, since the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment has a connection configuration equivalent to that of the stacked thin film photoelectric conversion device, the photoelectric conversion elements 3 and 8 operate at an optimum operating point. Power generation efficiency is improved. As a result, the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment can realize the photoelectric conversion efficiency equivalent to that of the stacked thin film photoelectric conversion device by the mechanical stack type photoelectric conversion device. It has a remarkable effect that has never been seen before.

  Further, in the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment, since the photoelectric conversion element pairs are connected in series with the same configuration as the stacked thin film photoelectric conversion device, conventionally two photoelectric conversions are performed. Output take-out sections required for each of the modules are collected in a single location (not shown). That is, it is only necessary to provide one output extraction unit for each of the photoelectric conversion elements at both ends among the plurality of photoelectric conversion elements connected in series. Thereby, since the structure of the thin film photoelectric conversion device 1 is simplified, the durability is excellent, the manufacturing process can be simplified, and the number of members used for the output extraction unit can be reduced, so that the cost can be reduced. Further, since there is no parallel connection of photoelectric conversion elements, a reverse voltage is unlikely to occur in the output extraction path.

  Further, in the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment, the transparent conductive layer 12 electrically connects between the photoelectric conversion element 3 and the photoelectric conversion element 8 constituting the photoelectric conversion element pair. Since the bonding can be realized at the same time, the electrical connection between the elements is reliable and easy.

  In the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment, the second photoelectric conversion module 7 is formed on an elongated conductive metal substrate 9. For this reason, even when a failure occurs in the second photoelectric conversion module 7, it is only necessary to remove the corresponding second photoelectric conversion module 7, and the second photoelectric conversion module 7 is formed on a single substrate having a large area. The yield is improved as compared with the case where two photoelectric conversion modules are formed. Moreover, since the 2nd photoelectric conversion module 7 is isolate | separated, the curvature and damage resulting from the difference in the expansion coefficient by the heat | fever of the photoelectric conversion element 3 and the photoelectric conversion element 8 can be suppressed.

Embodiment 2. FIG.
FIG. 6 is a perspective view showing a schematic configuration of a mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment of the present invention. FIG. 7 is an exploded perspective view illustrating a state where the opposing photoelectric conversion modules in the mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment are disassembled. FIG. 8 is an exploded perspective view illustrating a state in which each layer of the photoelectric conversion module in the mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment is disassembled.

  The mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment includes a first photoelectric conversion module 22 and a second photoelectric conversion module 27 which are thin film photoelectric conversion modules each including a plurality of photoelectric conversion elements. Has a configuration in which the photoelectric conversion elements are attached to each other, and light enters from the first photoelectric conversion module 22 side.

  The first photoelectric conversion module 22 includes a plurality of photoelectric conversion elements 23a, 23b, 23c, and 23d (hereinafter may be collectively referred to as photoelectric conversion elements 23), which are first photoelectric conversion elements. The photoelectric conversion element 23 has a texture structure (not shown) on the surface opposite to the light-transmitting insulating substrate 24 on the light-transmitting insulating substrate 24 that is the first light-transmitting insulating substrate. The transparent electrode layer 25, which is a first transparent electrode layer patterned in a stripe shape extending in a direction substantially parallel to the short direction of the conductive insulating substrate 24, and substantially parallel to the short direction of the translucent insulating substrate 4 A thin film semiconductor layer 26 that is a first thin film semiconductor layer patterned in a stripe shape extending in the direction is sequentially stacked. In the first photoelectric conversion module 22, adjacent photoelectric conversion elements 23 are not electrically connected.

  6 to 8 illustrate the case where the first photoelectric conversion module 22 includes four adjacent photoelectric conversion elements 23a, 23b, 23c, and 23d, the first photoelectric conversion module 22 includes. The number of photoelectric conversion elements 23 is not limited to this, and a larger number of photoelectric conversion elements 23 may be formed on the translucent insulating substrate 24.

  In the mechanical stack type thin film photoelectric conversion device 21, since light enters from the first photoelectric conversion module 22 side, the translucent insulating substrate 24 is a plate made of a translucent insulating material such as glass or transparent resin. A sheet-like member or a sheet-like member is used.

For the transparent electrode layer 25, a transparent conductive oxide (TCO) such as tin oxide (SnO ₂ ), zinc oxide (ZnO), indium oxide (In ₂ O ₃ ), or the like is used as a transparent conductive film having optical transparency. It is formed using a method such as CVD (Chemical Vapor Deposition), sputtering, or vapor deposition. Further, the transparent electrode layer 25 has a surface texture structure (not shown) in which a concavo-convex shape is formed on the surface opposite to the translucent insulating substrate 24. This texture structure has a function to scatter incident sunlight, absorb incident light more efficiently by the first photoelectric conversion module 22 and the second photoelectric conversion module 27, and increase light use efficiency. Further, the transparent electrode layer 25 has outer peripheral connection portions 33 that are electrical connection regions at both ends in the short direction of the translucent insulating substrate 24. Note that an undercoat layer made of silicon oxide (SiO ₂ ) or the like may be formed on the light-transmitting insulating substrate 24 as a blocking layer for impurities from the light-transmitting insulating substrate 24 as necessary.

  The thin film semiconductor layer 26 is disposed behind the transparent electrode layer 25 as viewed from the light incident side, has a P-I-N structure, and is configured by laminating one or more thin film semiconductor layers that generate power by incident light. The The thin film semiconductor layer 26 includes a P-type semiconductor layer that is a first conductive type semiconductor layer from the translucent insulating substrate 24 side, an I-type semiconductor layer that is a substantially intrinsic photoelectric conversion layer and is a second conductive type semiconductor layer, And a PIN junction composed of an N-type semiconductor layer which is a third conductivity type semiconductor layer. In the present embodiment, the thin film semiconductor layer 26 includes, in order from the translucent insulating substrate 24 side, a P-type hydrogenated amorphous silicon carbide (a-SiC: H) layer, which is a first conductive type semiconductor layer, and a second conductive type. P-I- consisting of an I-type hydrogenated amorphous silicon (a-Si: H) layer as a type semiconductor layer and an N-type hydrogenated amorphous silicon (a-Si: H) layer as a third conductivity type semiconductor layer N junction is formed.

  The thin-film semiconductor layer 26 is a P-type hydrogenated amorphous silicon carbide (a-SiC: H) layer or a second conductivity-type semiconductor layer that is a first conductivity-type semiconductor layer from the translucent insulating substrate 24 side. I-type hydrogenated amorphous silicon (a-Si: H) layer, N-type hydrogenated microcrystalline silicon (μc-Si: H) layer as a third conductivity type semiconductor layer, P as a first conductivity-type semiconductor layer Type hydrogenated microcrystalline silicon (μc-Si: H) layer, second conductivity type semiconductor layer I type hydrogenated microcrystalline silicon (μc-Si: H) layer, third conductivity type semiconductor layer N Alternatively, a two-stage PIN junction composed of a hydrogenated microcrystalline silicon (μc-Si: H) layer may be used.

Further, when a plurality of thin film semiconductor layers are stacked to form the thin film semiconductor layer 26 as in the above-described two-stage P-I-N junction, oxide microcrystals are formed between the respective P-I-N junctions. Inserting an intermediate layer such as silicon (μc-SiO _x (X = 0-2)) or aluminum-added zinc oxide (ZnO: Al) to improve electrical and optical connection between P-I-N junctions May be.

  The second photoelectric conversion module 27 includes a plurality of photoelectric conversion elements 28a, 28b, 28c, and 28d (hereinafter may be collectively referred to as photoelectric conversion elements 28), which are second photoelectric conversion elements. The photoelectric conversion element 28 has a back surface patterned to the same shape as the conductive metal substrate 29 having a textured structure on the surface opposite to the conductive metal substrate 29 on an elongated conductive metal substrate 29 having an uneven shape on the surface. A transparent electrode layer 30 and a thin film semiconductor layer 31 which is a second thin film semiconductor layer patterned in a stripe shape extending in a direction substantially parallel to the short direction of the translucent insulating substrate 24 are sequentially laminated. Yes. In the second photoelectric conversion module 7, adjacent photoelectric conversion elements 28 are not electrically connected to each other.

  6 to 8 show four adjacent photoelectric conversion elements 28a, 28b, 28c, and 28d among the second photoelectric conversion modules 27 for convenience, the photoelectrics included in the second photoelectric conversion module 27 are shown. The number of conversion elements 28 is not limited to this, and a large number of photoelectric conversion elements 28 are formed on the conductive metal substrate 9.

  As the conductive metal substrate 29, for example, a metal substrate such as silver (Ag) or aluminum (Al) is used. The conductive metal substrate 29 has a concavo-convex structure larger (gradual) than the texture structure included in the transparent electrode layer 25 on the surface on the back surface transparent electrode layer 30 side.

The back transparent electrode layer 30 uses a transparent conductive oxide (TCO) such as tin oxide (SnO ₂ ), zinc oxide (ZnO), indium oxide (In ₂ O ₃ ), for example, as a transparent conductive film having optical transparency. And formed using a method such as CVD, sputtering, or vapor deposition. Moreover, the back surface transparent electrode layer 30 has a shape along the surface shape of the conductive metal substrate 29 and has a texture structure having a concavo-convex structure larger than the texture structure of the transparent electrode layer 25 on both main surfaces. . This texture structure is an uneven structure suitable for light absorption for the thin film semiconductor layer 31 of the second photoelectric conversion module 27. The back transparent electrode layer 30 has outer peripheral connection portions 34 that are electrical connection regions at both ends in the short direction of the translucent insulating substrate 24. Note that an undercoat layer made of silicon oxide (SiO ₂ ) or the like may be formed on the conductive metal substrate 29 as a blocking layer for impurities from the conductive metal substrate 29 as necessary.

  The thin film semiconductor layer 31 is disposed in front of the back transparent electrode layer 30 as viewed from the light incident side, has a PIN structure, and includes one or more thin film semiconductor layers that generate power by incident light. Is done. The thin film semiconductor layer 31 includes, from the back transparent electrode layer 30 side, an N-type semiconductor layer that is a third conductive semiconductor layer, an I-type semiconductor layer that is a substantially intrinsic photoelectric conversion layer and is a second conductive semiconductor layer, and a first conductive layer. An N-I-P junction composed of a P-type semiconductor layer which is a one-conductivity-type semiconductor layer is formed. In the present embodiment, the thin film semiconductor layer 31 includes, in order from the back transparent electrode layer 30 side, an n-type hydrogenated microcrystalline silicon (μc-Si: H) layer, which is a third conductivity type semiconductor layer, and a second conductivity type. An N-type consisting of an i-type hydrogenated microcrystalline silicon (μc-Si: H) layer as a semiconductor layer and a p-type hydrogenated microcrystalline silicon (μc-Si: H) layer as a first conductivity type semiconductor layer. An IP junction is formed.

  In addition, the thin film semiconductor layer 31 is an n-type hydrogenated microcrystalline silicon (μc-Si: H) layer that is a third conductivity type semiconductor layer and i that is a second conductivity type semiconductor layer from the back transparent electrode layer 30 side. Type hydrogenated microcrystalline silicon (μc-Si: H) layer, p-type hydrogenated microcrystalline silicon (μc-Si: H) layer as a first conductivity type semiconductor layer, n as a third conductivity type semiconductor layer Type hydrogenated microcrystalline silicon (μc-Si: H) layer, i-type hydrogenated amorphous silicon germanium (a-SiGe: H) layer as the second conductivity type semiconductor layer, p as the first conductivity type semiconductor layer Alternatively, a two-stage N-I-P junction structure including a hydrogenated microcrystalline silicon (μc-Si: H) layer may be used.

Further, in the case where the thin film semiconductor layer 11 is configured by laminating a plurality of thin film semiconductor layers as in the above-described two-stage NIP junction, an oxide microcrystal is formed between the NIP junctions. Inserting an intermediate layer such as silicon (μc-SiO _x (X = 0-2)) or aluminum-added zinc oxide (ZnO: Al) to improve the electrical and optical connection between NIP junctions May be.

  As a combination of the first photoelectric conversion module 22 and the second photoelectric conversion module 27, the lamination form of the thin film semiconductor layer in each module is, for example, (1) 1-stage pin junction-1 stage nip junction, (2) 2-stage Pin junction-1 stage nip junction, (3) 1 stage pin junction-2 stage nip junction, (4) 2 stage pin junction-2 stage nip junction.

  Moreover, the width in the longitudinal direction of the translucent insulating substrate 24 in the photoelectric conversion element 23 and the width in the longitudinal direction of the translucent insulating substrate 24 in the photoelectric conversion element 28 are substantially the same, and the thin film photoelectric conversion is performed. In the device 21, the photoelectric conversion element 23 and the photoelectric conversion element 28 are arranged at positions facing each other, and constitute a pair of the photoelectric conversion element 23 and the photoelectric conversion element 28.

  That is, in FIGS. 6 to 8, the photoelectric conversion element 23 a and the photoelectric conversion element 28 a are arranged at positions facing each other to constitute a photoelectric conversion element pair, and the photoelectric conversion element 23 b and the photoelectric conversion element 28 b are relative to each other. A photoelectric conversion element pair is configured by being arranged at a position where Further, the photoelectric conversion element 23c and the photoelectric conversion element 28c are arranged at positions facing each other to constitute a photoelectric conversion element pair, and the photoelectric conversion element 23d and the photoelectric conversion element 28d are arranged at positions facing each other to perform photoelectric conversion. An element pair is configured. This photoelectric conversion element pair can be regarded as a new photoelectric conversion element.

  In the photoelectric conversion element 23 and the photoelectric conversion element 28 which face each other, the thin film semiconductor layer 26 and the thin film semiconductor layer 31 are electrically connected by the transparent conductive layer 32 disposed between the thin film semiconductor layer 26 and the thin film semiconductor layer 31. Connected to and bonded. The transparent conductive layer 32 is made of, for example, a metal paste or an anisotropic conductive film, and has both transparency and conductivity. The transparent conductive layer 32 is made of a metal alkoxide solution obtained by mixing a metal oxide such as zinc oxide or tin oxide with an organic solvent such as ethanol, 2-methoxyethanol, or monoethanolamine. And the thin film semiconductor layer 31 are applied and fired on the entire surface. The transparent conductive layer 32 can be replaced with a resin or sheet having both transparency and conductivity. It may be one in which metal particles or conductive oxide particles are dispersed in a transparent resin.

  With such a configuration, all the photoelectric conversion elements 23 and photoelectric conversion elements 28 are alternately connected in series as in the equivalent circuit shown in FIG. That is, the opposing photoelectric conversion element 23 and the photoelectric conversion element 28 are electrically connected directly, and have the same element configuration as a stacked thin film photoelectric conversion element formed on the same substrate, and a mechanical stack type thin film photoelectric conversion. All the photoelectric conversion element pairs of the device 21 have substantially the same characteristics. And in the thin film photoelectric conversion apparatus 21, a power drop can be prevented compared with parallel connection. In addition, since the elements of the first photoelectric conversion module 22 and the second photoelectric conversion module 27 are connected in series, compared to the case where the first photoelectric conversion module 22 and the second photoelectric conversion module 27 are paralleled. The voltage can be easily increased, and loss due to wiring resistance can be reduced.

  As shown in FIGS. 6 to 8, in the adjacent photoelectric conversion element pair, the transparent electrode layer 25 of one first photoelectric conversion module 22 and the back surface transparent electrode layer 30 of the other second photoelectric conversion module 27. Are the outer peripheral connection portion 33 of the transparent electrode layer 25 in the short direction of the translucent insulating substrate 24 and the outer peripheral connection portion 34 of the back surface transparent electrode layer 30 in the short direction of the translucent insulating substrate 24, They are electrically connected by a certain conductive layer 35. The conductive layer 35 is not particularly limited as long as it can contact the transparent electrode layer 25 and the back transparent electrode layer 30 such as an electrode paste, a conductive resin, or a conductive sheet. Such a conductive layer 35 is obtained by press-bonding the thin film semiconductor layer 26 and the thin film semiconductor layer 31 after applying a conductive paste to the outer peripheral connection portion 33 and the outer peripheral connection portion 34. As a result, the pair of opposing photoelectric conversion elements 23 and the photoelectric conversion elements 28 are electrically connected. With such a configuration, adjacent photoelectric conversion element pairs are electrically connected directly, and an element configuration similar to that in a case where stacked thin film photoelectric conversion elements formed on the same substrate are connected in series is obtained.

  The connection by the connection member according to the second embodiment will be described in more detail. In the first photoelectric conversion module 22, the transparent electrode layer 25 on the translucent insulating substrate 24 has a region protruding from the bottom of the thin film semiconductor layer 26. This protruding region becomes an outer peripheral connection portion 33 located on the outer side of the longitudinal end portion of the thin film semiconductor layer 26 divided for each element. The outer peripheral connection portion 33 has an extending portion extending to the adjacent photoelectric conversion element pair side, and the extending portion is located to the outside of the longitudinal end portion of the first thin film semiconductor layer 26. Moreover, the outer periphery connection part 33 is the shape extended from the middle of the edge part of the longitudinal direction of the 1st thin film semiconductor layer 26 to the adjacent photoelectric conversion element pair side so that this extension part may not contact with the adjacent outer periphery connection part 33. It is said that.

  On the other hand, in the second photoelectric conversion module 27, the back transparent electrode layer 30 on the conductive metal substrate 29 has a region protruding from the bottom of the thin film semiconductor layer 31. This protruding region becomes the outer peripheral connection portion 34 located on the outer side of the end portion in the longitudinal direction of the thin film semiconductor layer 31 divided for each element. When the translucent insulating substrate 24 and the conductive metal substrate 29 are opposed to each other, the outer peripheral connection portion 34 is located at a position facing the extending portion of the outer peripheral connection portion 33 of the adjacent photoelectric conversion element pair.

  By forming the outer periphery connection portion 33 and the outer periphery connection portion 34 in such a shape, the photoelectric conversion element pairs can be connected in series with a simple configuration in which the conductive layer 35 is sandwiched therebetween. The conductive layer 35 is a connection member that extends from the other substrate side toward the connection portion of one substrate. The connecting member becomes an electrical path substantially perpendicular to the substrate, and the resistance of the connecting member can be reduced. Further, as shown in the figure, it is desirable that the outer peripheral connection portion 33 and the outer peripheral connection portion 34 of the same photoelectric conversion element pair have a non-opposing shape, so that it is possible to prevent a short circuit due to conductive dust or the like sandwiched therebetween. .

  In the above description, the extending portion is provided on the outer peripheral connecting portion 33 side. However, the same connection is possible even if provided on the outer peripheral connecting portion 34 side. In the figure, the outer peripheral connection portion 33 and the outer peripheral connection portion 34 are provided on both sides of the substrate. However, the thin film semiconductor layer is divided by dividing the thin film semiconductor layer in the middle of the substrate, and such connection is made in one groove. A location may be provided. Further, it is not essential that the conductive layer 35 is in direct contact with the transparent electrode layer 25 or the back surface transparent electrode layer 30. For example, in the case of having a conductive film formed so as to be in contact with the transparent electrode layer 25 or the back surface transparent electrode layer 30, the conductive layer 35 may be in contact with those conductive films. Moreover, the outer periphery connection part 33 and the outer periphery connection part 34 may be formed with such an electrically conductive film.

  The mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment has the same basic steps as the mechanical stack type thin film photoelectric conversion device 1 according to the first embodiment. It is made as follows.

First, the first photoelectric conversion module 22 is manufactured. First, for example, a flat glass substrate is prepared as the translucent insulating substrate 24, and on one surface side of the translucent insulating substrate 24, tin oxide (SnO ₂ ), zinc oxide (having an uneven texture structure on the surface) is prepared. A transparent electrode layer 25 made of a transparent conductive oxide (TCO) such as ZnO) or indium oxide (In ₂ O ₃ ) is formed by a method such as CVD, sputtering, or vapor deposition. Here, the transparent electrode layer 25 has a stripe shape extending in a direction substantially parallel to the transversal direction of the translucent insulating substrate 24, and has outer peripheral connection portions at both ends in the transversal direction of the translucent insulating substrate 24. Patterned into a shape having 33.

  Next, a thin film semiconductor layer 6 for photoelectric conversion made of, for example, amorphous silicon is formed on the transparent electrode layer 25 by a plasma CVD method or the like in a stripe shape extending in a direction substantially parallel to the short direction of the translucent insulating substrate 4. To form. The thin film semiconductor layer 26 is, for example, a p-type hydrogenated amorphous silicon carbide (a-SiC: H) layer, which is a first conductive type semiconductor layer, or a second conductive type semiconductor layer, from the translucent insulating substrate 24 side. An i-type hydrogenated amorphous silicon (a-Si: H) layer and an n-type hydrogenated amorphous silicon (a-Si: H) layer as a third conductivity type semiconductor layer are sequentially formed. Thereby, the 1st photoelectric conversion module 22 is obtained.

  Next, the second photoelectric conversion module 27 is manufactured. First, as the conductive metal substrate 29, for example, a metal substrate that reflects light such as silver (Ag) or aluminum (Al) having an uneven texture structure on one side is prepared. Here, the texture structure is a texture structure having a concavo-convex structure larger (gradual) than the texture structure on the surface of the transparent electrode layer 25.

Next, a back transparent electrode made of a transparent conductive oxide (TCO) such as tin oxide (SnO ₂ ), zinc oxide (ZnO), or indium oxide (In ₂ O ₃ ) is formed on one side of the conductive metal substrate 29. Layer 30 is formed using a method such as CVD, sputtering, or vapor deposition. On the conductive metal substrate 29, an undercoat layer made of silicon oxide (SiO ₂ ) or the like may be formed as a blocking layer for impurities from the conductive metal substrate 29 as necessary.

  Next, a thin film semiconductor layer 31 for photoelectric conversion made of, for example, hydrogenated microcrystalline silicon is formed on the back transparent electrode layer 30 by a plasma CVD method or the like. As the thin-film semiconductor layer 31, from the back transparent electrode layer 30 side, an n-type hydrogenated microcrystalline silicon (μc-Si: H) layer that is a third conductivity type semiconductor layer, and an i-type that is a second conductivity type semiconductor layer. A hydrogenated microcrystalline silicon (μc-Si: H) layer and a p-type hydrogenated microcrystalline silicon (μc-Si: H) layer which is a first conductive type semiconductor layer are sequentially formed.

  Then, the 2nd photoelectric conversion module 27 is obtained by dividing | segmenting into the some photoelectric conversion element 8 by a laser scribe, for example. Here, the second photoelectric conversion module 27 is divided for each conductive metal substrate 29. In addition, the second photoelectric conversion module 27 has a striped shape extending in a direction substantially parallel to the short direction of the conductive metal substrate 29, and back surface transparent electrodes at both ends in the short direction of the conductive metal substrate 29. The layer 30 is patterned into a shape having the outer peripheral connection portion 34. The outer peripheral connection portion 34 is formed at a position facing the outer peripheral connection portion 33 when the mechanical stack type thin film photoelectric conversion device 21 is assembled.

  Next, on the entire surface of the first photoelectric conversion module 22 on the thin film semiconductor layer 26 and on the entire surface of the second photoelectric conversion module 27 on the thin film semiconductor layer 31, for example, a metal oxide such as zinc oxide or tin oxide and, for example, ethanol. A metal alkoxide solution mixed with an organic solvent such as 2-methoxyethanol or monoethanolamine is applied and pre-baked. Further, for example, an electrode paste is applied to the outer peripheral connection portions 33 at both ends of the translucent insulating substrate 24 of the first photoelectric conversion module 22.

  Then, the application surfaces of the first photoelectric conversion module 22 and the second photoelectric conversion module 27 are made to face each other so that the photoelectric conversion element 23 and the photoelectric conversion element 28 forming the photoelectric conversion element pair face each other. After the pressure bonding, the main baking is performed. Thereby, the transparent conductive layer 32 is formed between the thin film semiconductor layer 26 and the thin film semiconductor layer 31. In addition, a conductive layer 35 is formed between the outer peripheral connection portion 33 and the outer peripheral connection portion 34.

  Here, the thin film semiconductor layer 26 of the first photoelectric conversion module 22 and the thin film semiconductor layer 31 of the second photoelectric conversion module 27 facing each other are transparent disposed between the thin film semiconductor layer 26 and the thin film semiconductor layer 31. They are electrically connected by the conductive layer 32. Moreover, the back surface transparent electrode layer 30 of the photoelectric conversion element 28 and the transparent electrode layer 25 of the photoelectric conversion element 23 constituting the adjacent pair are conductive layers arranged between the outer peripheral connection portion 33 and the outer peripheral connection portion 34. 35 is electrically connected.

  As a result, a mechanical stack type thin film photoelectric conversion device 21 in which the first photoelectric conversion module 2 and the second photoelectric conversion module 27 are bonded together as shown in FIGS. 6 to 8 is obtained. Thereafter, one output extraction portion is formed at each of the photoelectric conversion elements at both ends among the plurality of photoelectric conversion elements connected in series.

  As described above, in the mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment, the opposing photoelectric conversion element pairs are electrically connected, and the photoelectric conversion elements 23 and the photoelectric elements constituting the adjacent pairs are electrically connected. By being electrically connected to the conversion element 28, all the photoelectric conversion elements 23 and the photoelectric conversion elements 28 are alternately connected in series as in the equivalent circuit shown in FIG. Thereby, since the thin film photoelectric conversion device 21 of the mechanical stack type according to the second embodiment has the same connection configuration as the stacked thin film photoelectric conversion device, the photoelectric conversion elements 23 and 28 operate at the optimum operating point, Power generation efficiency is improved. As a result, the mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment can realize the photoelectric conversion efficiency equivalent to that of the stacked thin film photoelectric conversion device by the mechanical stack type photoelectric conversion device. It has a remarkable effect that has never been seen before.

  Further, in the mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment, the photoelectric conversion element pairs are connected in series with the same configuration as that of the stacked thin film photoelectric conversion device. Output take-out sections required for each of the modules are collected in a single location (not shown). That is, it is only necessary to provide one output extraction unit for each of the photoelectric conversion elements at both ends among the plurality of photoelectric conversion elements connected in series. Thereby, since the structure of the thin film photoelectric conversion device 21 is simplified, the durability is excellent, the manufacturing process can be simplified, and the number of members used for the output extraction unit can be reduced, so that the cost can be reduced. Further, since there is no parallel connection of photoelectric conversion elements, a reverse voltage is unlikely to occur in the output extraction path.

  Further, in the mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment, the transparent conductive layer 32 electrically connects the photoelectric conversion element 23 and the photoelectric conversion element 28 that constitute the photoelectric conversion element pair. Since the bonding can be realized at the same time, the electrical connection between the elements is reliable and easy.

  In the mechanical stack type thin film photoelectric conversion device 21 according to the second embodiment, the second photoelectric conversion module 27 is formed on an elongated conductive metal substrate 29. For this reason, even if a failure occurs in the second photoelectric conversion module 27, it is only necessary to remove the corresponding second photoelectric conversion module 27, and the second photoelectric conversion module is formed on one large-area substrate. Yield is better than if it is. Moreover, since the 2nd photoelectric conversion module 27 is isolate | separated, the curvature and damage resulting from the difference in the expansion coefficient by the heat | fever of the photoelectric conversion element 23 and the photoelectric conversion element 28 can be suppressed.

  Furthermore, in the thin film photoelectric conversion device 21 of the mechanical stack system according to the second embodiment, the back surface transparent electrode layer 30 of the photoelectric conversion element 28 and the transparent electrode layer 25 of the photoelectric conversion element 23 constituting the adjacent pair, Since the electrical connection is made by the conductive layer 35 disposed between the outer peripheral connection part 33 and the outer peripheral connection part 34 which are displaced from the main region of the photoelectric conversion element, the photoelectric conversion element 23 and the photoelectric conversion element 28 are easily connected. Can be connected in series.

  In the above embodiment, the back transparent electrode layer 30 is formed between the conductive metal substrate 29 of the second photoelectric conversion module 27 and the thin film semiconductor layer 31, but the back transparent electrode layer 30 is not necessarily essential. Absent. When the back transparent electrode layer 30 is not provided, the conductive metal substrate 29 itself becomes the second substrate side electrode. When the thin film semiconductor layer 31 is made of a material containing silicon as a main component and the conductive metal substrate 29 is made of a material such as silver (Ag) that easily diffuses into silicon, the back transparent electrode layer 30 is desirable as a diffusion preventing layer. However, the back transparent electrode layer 30 may be omitted when these materials are difficult to interact with each other or when such an interaction preventing process is performed.

  Moreover, although the case where the electroconductive metal substrate 29 was used in the 2nd photoelectric conversion module 27 was shown in said embodiment, the electroconductive metal substrate in which the metal film was formed on the insulating substrate may be sufficient. In the second embodiment, the case where the conductive metal substrate 29 divided for each pair of photoelectric conversion elements is used is shown. However, the conductive metal substrate 29 described in the second embodiment is formed on one insulating substrate. A conductive metal substrate in which a metal film pattern having a similar shape is divided for each element may be used. In that case, the process of bonding the substrates facing each other is simplified, and a peripheral portion of the bonded substrates is sealed, whereby a highly reliable photoelectric conversion device is obtained. Further, it is desirable to use the same material as the substrate 22 of the first photoelectric conversion module for the insulating substrate because deformation due to a difference in thermal expansion accompanying a temperature change can be prevented.

  As described above, the thin film photoelectric conversion device according to the present invention is useful for realizing high power generation efficiency similar to that of the stacked thin film photoelectric conversion device with a mechanically stacked photoelectric conversion device having a simple configuration.

DESCRIPTION OF SYMBOLS 1 Thin film photoelectric conversion apparatus 2 1st photoelectric conversion module 3 Photoelectric conversion element 3a Photoelectric conversion element 3b Photoelectric conversion element 4 Translucent insulating substrate 5 Transparent electrode layer 6 Thin film semiconductor layer 7 2nd photoelectric conversion module 8 Photoelectric conversion element 8a Photoelectric conversion element 8b Photoelectric conversion element 9 Conductive metal substrate 10 Back surface transparent electrode layer 11 Thin film semiconductor layer 12 Transparent conductive layer 13 Insulating resin 14 Metal substrate 21 First thin film photoelectric conversion device 22 Photoelectric conversion module 23 Photoelectric conversion element 23a Photoelectric Conversion element 23b Photoelectric conversion element 23c Photoelectric conversion element 23d Photoelectric conversion element 24 Translucent insulating substrate 25 Transparent electrode layer 26 Thin film semiconductor layer 27 Second photoelectric conversion module 28 Photoelectric conversion element 28a Photoelectric conversion element 28b Photoelectric conversion element 28c Photoelectric conversion Element 28d Photoelectric conversion element 29 Conductive metal substrate 30 Back Transparent electrode layer 31 thin film semiconductor layer 32 transparent conductive layer 33 the outer peripheral connecting portion 34 the outer peripheral connecting portion 35 the conductive layer 201 photoelectric conversion element 202 photoelectrically converting element 211 first photoelectric conversion module 212 and the second photoelectric conversion module

Claims (8)

A first photoelectric conversion module in which a plurality of first photoelectric conversion elements in which a first substrate side electrode and a first photoelectric conversion layer are sequentially formed on one surface of a first substrate having translucency and insulation; A second photoelectric conversion module in which a plurality of second photoelectric conversion elements each having a second substrate side electrode and a second photoelectric conversion layer formed in order on one surface of the two substrates are the first photoelectric conversion element and the first photoelectric conversion element; 2 It is bonded with the photoelectric conversion element inside,
A plurality of pairs of photoelectric conversion elements configured such that the first photoelectric conversion element and the second photoelectric conversion element arranged at opposite positions are electrically connected in series with a transparent conductive layer interposed therebetween;
In the adjacent photoelectric conversion element pairs, one of the first substrate side electrodes and the other second substrate side electrode are electrically connected by a connecting member, whereby the adjacent photoelectric conversion element pairs are electrically connected in series. Being connected,
A photoelectric conversion device characterized by the above. The first photoelectric conversion element has a first connection portion that protrudes from below the first photoelectric conversion layer on the first substrate, and the connection member faces the first connection portion from the second substrate side. Being an extended member,
The photoelectric conversion device according to claim 1. The second substrate is divided for each second photoelectric conversion element;
The photoelectric conversion device according to claim 1, wherein: The second substrate is made of a conductive metal electrically connected to the second substrate side electrode,
The connection member is sandwiched between insulating photoelectric layers between adjacent photoelectric conversion element pairs and insulated from the first photoelectric conversion layer, the transparent conductive layer, and the second photoelectric conversion layer, and one of the first photoelectric conversion layers. A metal member that electrically connects the substrate-side electrode and the other second substrate-side electrode;
The photoelectric conversion device according to claim 3. The second substrate-side electrode has a second connection portion that protrudes from below the second photoelectric conversion layer on the second substrate, and one of the second connection portion and the other of the adjacent photoelectric conversion element pair The first connection portion is provided at a position opposite to each other, and the connection member is a member sandwiched between the second connection portion and the first connection portion;
The photoelectric conversion device according to claim 2, wherein: The first photoelectric conversion layer and the second photoelectric conversion layer have a shape that is long in a specific direction, and the first connection portion and the second connection portion are formed of the first photoelectric conversion layer and the second photoelectric conversion layer. Provided on the side in the longitudinal direction, at least one of the first connection portion and the second connection portion has a shape extending to the side in the longitudinal direction of the adjacent photoelectric conversion element pair;
The photoelectric conversion device according to claim 5. The second substrate is made of a conductive metal electrically connected to the second substrate side electrode,
The first substrate and the second substrate each have an outer peripheral connection portion that is an electrical connection region on the outer peripheral portion of the substrate,
The connection member is a conductive layer that electrically connects an outer peripheral connection portion of one of the first substrates and an outer peripheral connection portion of the other second substrate in the adjacent photoelectric conversion element pair;
The photoelectric conversion device according to claim 3. The first photoelectric conversion layer and the second photoelectric conversion layer have uneven shapes of different sizes;
The photoelectric conversion device according to claim 1, wherein:

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