JP2014045124A - Solar cell and manufacturing method therefor, solar cell module and manufacturing method therefor - Google Patents

Abstract

The solar cell substrate is provided with high reliability in connection between the electrode on the back surface side of the solar cell substrate and the wiring of the wiring substrate, and avoids a short circuit between adjacent electrodes on the back surface side of the solar cell substrate. The solar cell which can aim at narrowing of the pitch of the electrode arrange | positioned at the back surface side of is realized.
A structure in which strip-shaped p-type semiconductor regions (comb teeth) 10b and strip-shaped n-type semiconductor regions (comb teeth) 20b are alternately arranged on the back surface opposite to the light receiving surface of an n-type silicon substrate 1. In the solar cell, a p-type electrode 11 formed on the strip-shaped p-type semiconductor region 10b so as to extend along this region, and an n-type electrode 12 formed on the strip-shaped n-type semiconductor region 20b so as to extend along this region. An electrode layer 12a formed so that the n-type electrode 12 is in contact with the n-type semiconductor region 20b, and a plating layer 12b formed so as to cover the electrode layer. The mold electrode 12 was covered with the insulating resin film 15 except for one end side portion.
[Selection] Figure 1

Description

  The present invention relates to a solar cell and a method for manufacturing the solar cell, and a solar cell module and a method for manufacturing the solar cell, and more particularly, a solar cell having a structure in which a collecting electrode is formed on the back surface opposite to the light receiving surface of a semiconductor substrate. The present invention relates to a method, a solar battery module using a solar battery having such a structure as a solar battery cell, and a manufacturing method thereof.

In recent years, a solar cell that directly converts solar energy into electric energy has been rapidly expected as a next-generation energy source particularly from the viewpoint of global environmental problems. As a solar cell,
There are various types such as those using compound semiconductors or organic materials, but the mainstream is currently using silicon crystals.

  Currently, the most manufactured and sold solar cells are a light receiving surface that is a surface on which sunlight is incident on a semiconductor substrate constituting the solar cell (hereinafter also referred to as a solar cell substrate or simply a substrate), In this structure, electrodes are formed on the back surface opposite to the light receiving surface.

  However, when an electrode is formed on the light receiving surface of the solar cell substrate, light is reflected or absorbed by the electrode, so that sunlight incident on the solar cell substrate is equivalent to the area of the electrode formed on the light receiving surface. Will decrease.

  Therefore, a back electrode type solar cell in which an electrode is formed only on the back surface of the solar cell substrate has been developed.

  In this back electrode type solar cell, by disposing the electrode on the back surface, the shadow area of the electrode on the light receiving surface is eliminated, and the pn junction is also located on the back surface side of the substrate. Even when an uneven structure (texture structure) for efficiently capturing sunlight is provided on the surface of the substrate, a good pn junction can be formed.

  FIG. 15 is a plan view for explaining a conventional back electrode type solar cell, and schematically shows the structure on the back surface side.

The solar cell 200 includes a p ⁺ type semiconductor region (diffusion region) having a substantially square solar cell substrate 210 made of, for example, an n-type silicon substrate, and a comb-shaped planar pattern formed on the back surface of the n-type silicon substrate 210. 201 and an n ⁺ -type semiconductor region (diffusion region) 202 having a comb-shaped planar pattern formed on the back surface of the substrate 210. Here, the p ⁺ -type semiconductor region (diffusion region) 201 and the n ⁺ -type semiconductor region (diffusion region) 202 are arranged so that the respective comb-shaped planar patterns penetrate each other. That is, on the back surface of the solar cell substrate 210, the comb tooth portions (parts equivalent to the comb teeth) 201 b of the p ⁺ type semiconductor region 201 and the comb tooth portions (comb teeth) of the n ⁺ type semiconductor region 202. and equality portion) 202b are alternately arranged, the comb tooth 201b of the ^{p +} -type semiconductor regions 201, at one end, is equivalent to the spine of the comb back (comb of the ^{p +} -type semiconductor region 201 parts ) and connected together to 201a, also part comb-tooth portion 202b of the ^{n +} -type semiconductor regions 202, at the other end, which equivalent to the spine of the comb back (comb ^{n +} -type semiconductor region 202) 202a is integrally connected.

A p-type electrode (comb-type p-type electrode) 211 having a planar pattern corresponding to the comb-shaped planar pattern is provided on the p ⁺ -type semiconductor region 201, and on the n ⁺ -type semiconductor region 202. Is provided with an n-type electrode (comb n-type electrode) 212 having a planar pattern corresponding to the comb-shaped planar pattern.

That is, the comb-type p-type electrode 211 is composed of the back portion 211a and the tooth portion 211b arranged on the comb back portion 201a and the comb tooth portion 201b of the p ⁺ type semiconductor region 201, and the comb-type n-type electrode 212 is The n ⁺ type semiconductor region 202 includes a back portion 212a and a tooth portion 212b disposed on the comb back portion 202a and the comb tooth portion 202b.

  FIG. 16 is a plan view for explaining a solar cell module using such a solar cell.

  This solar cell module 220 is formed by connecting the solar cells 200 shown in FIG. 15 in series. The solar cell module 220 shown in FIG. 16 has three solar cells having the same structure as the solar cell 200 shown in FIG. 200a to 200c are connected in series.

  That is, this solar cell module 220 connects the back portion 211a of the p-type electrode 211 of the central solar cell 200b to the back portion 212a of the n-type electrode 212 of the solar cell 200a on one side by the electrode connecting member 221, thereby The back portion 212a of the n-type electrode 212 of the battery 200b is connected to the back portion 211a of the p-type electrode 211 of the solar cell 200c on the other side by the electrode connecting member 221.

However, in such a solar cell using a comb-shaped electrode, it is necessary to increase the teeth of the comb-shaped electrode in order to reduce the resistance of the electrode. Therefore, it is necessary to provide a margin for the interval between the teeth of the comb-shaped electrodes having different sizes. For this reason, the interval between the teeth of the comb-tooth 201b in the p ⁺ -type semiconductor region 201 and the interval between the comb-tooth portions 202b in the n ⁺ -type semiconductor region 202 ( As a result, the width of the pn junction surface that can be secured on one solar cell substrate is limited, and there is a problem that the current collection efficiency cannot be increased.

  Therefore, as a solution to the reduction in the resistance of the electrodes of the solar cell and the peak of current collection efficiency due to the margin of the arrangement interval, the electrode of the solar cell was formed on the mounting substrate (wiring substrate) side, There is a solar cell of a system (hereinafter referred to as a wiring sheet system) connected to a wiring including the same plane pattern as the electrode.

  FIG. 17 and FIG. 18 are diagrams for explaining a conventional solar cell of a wiring sheet type, FIG. 17 shows the arrangement of semiconductor regions on the back side of the substrate, and FIG. 18 shows the back side of the solar cell substrate. The arrangement of the electrodes is shown.

For example, in this solar cell 300, strip-shaped p ⁺ -type semiconductor regions 301 and strip-shaped n ⁺ -type semiconductor regions 302 are alternately arranged on the back surface of the substrate 310. Further, as shown in FIG. 18, a p-type electrode 311 extending along this region is provided on the belt-like p ⁺ type semiconductor region 301 so as to be electrically connected to the region 301. As shown in FIG. 18, an n-type electrode 312 extending along this region is provided on the n ⁺ -type semiconductor region 302 so as to be electrically connected to the region 302.

  FIG. 19 is a diagram for explaining the structure of a wiring board on which such a wiring sheet type solar cell is mounted.

  A wiring board 350 shown in FIG. 19 has a plurality of mounting regions R on which the solar cells 300 shown in FIGS. 17 and 18 are mounted. Here, the wiring board 350 has a structure having 16 mounting regions R, and the insulating sheet material 350a constituting the wiring substrate 350 includes a p-type wiring 351 and an n-type wiring 352 for each mounting region R. When the solar cell 300 is disposed in the mounting region R, the p-type electrode 311 and the n-type electrode 312 of the solar cell correspond to the corresponding p-type wire 351 of the wiring board. And it arrange | positions so that the n-type wiring 352 may be opposed.

  Here, one p-type wiring 351 and the other n-type wiring 352 in two adjacent mounting regions arranged side by side in the direction in which each wiring extends (the vertical direction in the drawing) are connected by the first connection wiring 354a. In addition, one p-type wiring 351 and the other n-type wiring 352 in the two mounting regions adjacent to each other along the side perpendicular to the direction in which each wiring extends of the wiring board 350 are the second The connection wiring 354b is connected. Further, here, the wiring pattern of the wiring board 350 is formed so that the solar cells arranged in each mounting region R are connected in series, and the p-type electrode 351 in the mounting region located at the head of the series connection is common. The n-type electrode 352 in the mounting region connected to the wiring 354c and located at the end of the series connection is connected to the common wiring 354d.

  The solar cell module 500 shown in FIG. 20 is obtained by mounting the above-described wiring sheet type solar cell 300 in each mounting region R of the wiring substrate 350.

  In such a wiring sheet type solar cell 300, low-resistance wiring is formed on the wiring substrate 350, so that the p-type electrode 311 and the n-type electrode 312 arranged on the solar cell substrate 310 are made of the solar cell substrate. Any device may be used as long as it collects the charges generated in the band-shaped p-type semiconductor region 301 and the band-shaped n-type semiconductor region 302 and delivers them to the p-type wiring 351 and the n-type wiring 352 of the wiring substrate 350. It is not necessary to move in the longitudinal direction, and a structure having a narrow width can be obtained without considering a reduction in resistance.

Thus, by adopting the wiring sheet method as the solar cell, the arrangement pitch of the band-shaped n ⁺ -type semiconductor region and the band-shaped p ⁺ -type semiconductor region formed on the back surface of the solar cell substrate is inevitably shortened. It becomes possible to increase power generation efficiency.

  In addition, there exists a thing disclosed in patent documents 1-3 as a solar cell of a back electrode type.

International Publication No. 2005/013321 Pamphlet JP 2009-88145 A JP 2010-16074 A

  By the way, in order to form the p-type electrode and the n-type electrode of the solar cell in a predetermined pattern, it is necessary to use an expensive resist or to perform a complicated etching process. As a method, for example, a method of forming a fired electrode as a p-type electrode and an n-type electrode by directly pattern-printing and firing a conductive paste containing a metal powder such as silver on the back surface of a solar cell substrate has been studied. However, there is a problem that the reliability of the connection between the fired electrode and the n-type wiring and the p-type wiring of the wiring board cannot be ensured only by the fired electrode formed by firing the silver paste because the surface area is small and the thickness is thin. .

  Therefore, the surface area and thickness of the electrode layer used as an electrode of the solar cell are increased by making the fired electrode thicker by plating, or by making the fired electrode covered with a conductive resin and thickened. Thus, a method for ensuring the reliability of the connection between the electrode of the solar cell and the wiring of the wiring board has been considered.

  However, in the structure in which the fired electrode is thickened by plating or the structure in which the fired electrode is covered with a conductive resin and thickened, the distance between the p-type electrode and the n-type electrode on the back surface of the solar cell substrate becomes narrow, and the dust Due to such adhesion, a short circuit is likely to occur between adjacent electrodes having different polarities, and it becomes difficult to narrow the pitch of the electrodes of the solar cell substrate.

  The present invention has been made to solve such a conventional problem, and can make the connection between the electrode on the back surface side of the solar cell substrate and the wiring of the wiring substrate highly reliable, Moreover, a solar cell capable of reducing the pitch of the electrodes arranged on the back surface side of the solar cell substrate while avoiding a short circuit between adjacent electrodes on the back surface side of the solar cell substrate, a method for manufacturing the solar cell, and the solar cell It is an object to obtain a module and a manufacturing method thereof.

  A solar cell according to the present invention includes a first conductivity type semiconductor substrate, the first main surface of the first conductivity type semiconductor substrate is a light receiving surface, and the opposite side to the first main surface of the first conductivity type semiconductor substrate. A solar cell in which a strip-shaped first conductive semiconductor region and a strip-shaped second conductive semiconductor region are alternately arranged on the second main surface of the first conductive semiconductor region along the region on the first conductive semiconductor region. A first electrode formed to extend; and a second electrode formed on the second conductivity type semiconductor region so as to extend along the region; and the first electrode has the first conductivity type. An electrode layer formed so as to be in contact with the semiconductor region; and a plating layer formed so as to cover the electrode layer, wherein the plating layer is formed of an insulating resin film except for one end side portion of the first electrode. This is a covered structure, whereby the above object is achieved.

  In the solar cell according to the present invention, the first electrode has a structure in which one end portion of the first electrode of the plating layer is covered with an adhesive including a conductive adhesive and an insulating adhesive. It is preferable that

  The present invention provides the solar cell, wherein the second electrode includes an electrode layer formed so as to be in contact with the second conductive semiconductor region, and the electrode layer constituting the second electrode is formed of a conductive adhesive. And a structure covered with an adhesive containing an insulating adhesive.

  In the solar cell according to the present invention, the electrode layers constituting the first electrode and the second electrode are preferably fired electrode layers obtained by firing a conductive paste containing metal powder.

  According to the present invention, in the solar cell, the conductive paste preferably includes silver as a metal powder, and the fired electrode layer is a silver electrode layer.

  According to the present invention, in the solar cell, the insulating resin film covering the plating layer of the first electrode is increased in viscosity from the uncured state by supplying energy to the uncured state. After the first cured state is reached, the viscosity is once lowered from the first cured state to be in a softened state, and then the viscosity is increased again to be in a state in which the viscosity is higher than the first cured state. The insulating adhesive material constituting the adhesive material has a property of being cured, and the energy is supplied to the uncured state, whereby the viscosity increases from the uncured state and the cured state. It is preferable to have the following properties.

  In the solar cell according to the aspect of the invention, it is preferable that the first cured state has a higher viscosity, lower adhesiveness, and shape retainability than an uncured state at normal temperature.

  In the solar cell according to the aspect of the invention, it is preferable that the band-shaped second conductive semiconductor region is wider than the band-shaped first conductive semiconductor region.

  According to the present invention, in the solar cell, the first conductive semiconductor substrate is an n-type silicon substrate, the second conductive semiconductor region is a p-type diffusion region in which boron is diffused, and the first conductive type The semiconductor region is preferably an n-type diffusion region in which phosphorus is diffused.

  A method for manufacturing a solar cell according to the present invention includes a first conductive semiconductor substrate, the first main surface of the first conductive semiconductor substrate is a light receiving surface, and the first main surface of the first conductive semiconductor substrate is Is a method of manufacturing a solar cell in which strip-shaped first conductive semiconductor regions and strip-shaped second conductive semiconductor regions are alternately arranged on the second main surface on the opposite side, wherein the first conductive semiconductor regions And a step of forming an electrode layer on each of the second conductivity type semiconductor regions so as to extend along these regions, and a step of selectively forming a plating layer only on the electrode layer on the first conductivity type semiconductor region. And a step of covering the plating layer formed on the electrode layer on the first conductive type semiconductor region with an insulating resin film except for one end side portion of the electrode layer on the first conductive type semiconductor region. Therefore, the above object can be achieved.

  According to the present invention, in the method for manufacturing a solar cell, a portion of the plating layer formed on the electrode layer of the first conductive type semiconductor region that is not covered with the insulating resin film, and on the second conductive type semiconductor region It is preferable to have a step of covering the electrode layer with an adhesive including an insulating adhesive and a conductive adhesive.

  The solar cell module according to the present invention is a solar cell module in which one or more solar cells are mounted on a wiring board, and the solar cell includes a first conductivity type semiconductor substrate, and the first conductivity type semiconductor substrate. A first conductive surface of the first conductive semiconductor substrate and a second conductive surface of the first conductive semiconductor substrate on a side opposite to the first main surface of the first conductive semiconductor substrate. The first electrode formed on the first conductive type semiconductor region so as to extend along the region, and the second conductive type semiconductor region along the region. A second electrode formed so as to extend, and the first electrode includes an electrode layer formed so as to be in contact with the first conductivity type semiconductor region, and a plating layer formed so as to cover the electrode layer. Including an insulating resin except for one end side portion of the first electrode. The wiring board is disposed in each mounting area where the solar cell is mounted so as to face the first electrode of the solar cell mounted on the wiring board, and the first The first wiring connected to the electrode and each mounting region for mounting the solar cell are arranged so as to face the second electrode of the solar cell mounted on the wiring board, and are connected to the second electrode. The first electrode is electrically connected to the first wiring at one end portion thereof, thereby achieving the above object.

  In the solar cell module according to the present invention, the first electrode and the first wiring are obtained by melting a solder resin applied to the surface of the plating layer in one end side portion of the first electrode. It is preferable to be connected by a conductive adhesive constituting the solder resin.

  The present invention provides the solar cell module, wherein the second electrode and the second wiring are obtained by melting a solder resin applied to a surface of an electrode layer constituting the second electrode. It is preferable that they are connected by a conductive adhesive that constitutes.

  In the solar cell module according to the present invention, a connection portion between the second electrode and the second wiring is applied to the surface of an electrode layer constituting the second electrode with respect to the first electrode. It is preferable that the insulating adhesive constituting the solder resin is electrically insulated from the insulating resin film covering the plating layer of the first electrode.

  A method for producing a solar cell module according to the present invention is a method for producing a solar cell module by mounting one or more solar cells on a wiring board, the solar cell comprising a first conductivity type semiconductor substrate, The first main surface of the first conductivity type semiconductor substrate is a light receiving surface, and the first main surface of the first conductivity type semiconductor substrate is opposite to the first main surface of the first main surface of the first conductivity type semiconductor substrate. Second conductivity type semiconductor regions are alternately arranged, the first electrode formed on the first conductivity type semiconductor region so as to extend along the region, and the second conductivity type semiconductor region. And a second electrode formed so as to extend along this region, the first electrode being formed so as to be in contact with the first conductivity type semiconductor region and covering the electrode layer A plated layer, and the plated layer is connected to one end side of the first electrode. The second electrode includes an electrode layer formed so as to be in contact with the second conductivity type semiconductor region, and the wiring substrate includes the solar cell. In each mounting region to be mounted, when the solar cell is mounted on the wiring board, the first wiring arranged to face the first electrode of the solar cell, and the mounting region in which the solar cell is mounted And a second wiring arranged so as to face the second electrode of the solar cell when the solar cell is mounted on the wiring board, and the method includes the first conductive semiconductor. A portion of the plated layer formed on the electrode layer in the region that is not covered with the insulating resin film, and the electrode layer on the second conductive type semiconductor region are bonded to each other including an insulating adhesive and a conductive adhesive. A step of coating with a material; and the solar cell on the wiring substrate. The first electrode and the second electrode are arranged so as to be opposed to the first and second wirings of the wiring board, and the insulating resin film and the adhesive are heat-treated. A portion of the plating layer formed on the electrode layer that is not covered with the insulating resin film is connected to the first wiring by a conductive adhesive contained in the adhesive, and the electrode of the second electrode And a step of connecting the layer and the second wiring with a conductive adhesive contained in the adhesive, thereby achieving the above object.

  Next, the operation will be described.

  In the present invention, the strip-shaped first conductive semiconductor region and the strip-shaped second conductive semiconductor region are formed on the second main surface opposite to the first main surface, which is the light receiving surface of the first conductive semiconductor substrate. In the alternately arranged solar cells, the first electrode of the first electrode on the first conductivity type semiconductor region and the second electrode on the second conductivity type semiconductor region is connected to the first conductivity type semiconductor region. A structure including an electrode layer formed so as to be in contact with and a plating layer formed so as to cover the electrode layer, and the plating layer is covered with an insulating resin film except for one end portion of the first electrode Therefore, the adjacent first electrode and the second electrode are insulated and separated by the insulating resin film covering the first electrode, and avoiding a short circuit between these electrodes. A narrow pitch can be achieved.

  The first electrode has a structure in which an electrode layer formed so as to be in contact with the first conductivity type semiconductor region is thickened by a plating layer formed so as to cover the electrode layer. In addition, the connection with the wiring of the wiring board on which the solar cell is mounted can be made highly reliable, and it is not necessary to use an expensive conductive resin to thicken the electrode layer of the first electrode. .

  Moreover, since only one of the first electrode and the second electrode of the solar cell is thickened by plating, the pitch between the electrodes is made narrower than when both electrodes are thickened by plating. Can do.

  As a result, the connection between the electrode on the back side of the solar cell substrate and the wiring on the wiring substrate can be made highly reliable, and the pitch of the electrodes can be reduced while avoiding a short circuit due to adhesion of dust or the like. In addition, a significant increase in the manufacturing cost of the solar cell can be avoided.

  As described above, according to the present invention, the connection between the electrode on the back surface side of the solar cell substrate and the wiring on the wiring substrate can be made highly reliable, and the adjacent electrode on the back surface side of the solar cell substrate. Solar cell capable of reducing the pitch of the electrodes arranged on the back surface side of the solar cell substrate while avoiding short circuit between the solar cell and the manufacturing method thereof, and the solar cell module and the manufacturing method thereof can be realized. .

FIG. 1 is a diagram for explaining a solar cell according to Embodiment 1 of the present invention. FIG. 1 (a) shows the structure of the back surface of the solar cell, and FIG. 1 (d) and FIG. FIG. 1B shows an enlarged view of the G1 portion and the G2 portion of FIG. 1A, FIG. 1B shows the cross-sectional structure of the E1-E1 ′ line portion of FIG. 1D, and FIG. The cross-section of the F1-F1 'line part of e) is shown. FIG. 2 is a diagram for explaining a solar cell according to Embodiment 1 of the present invention, and FIG. 2 (a), FIG. 2 (b), FIG. 2 (c), and FIG. The structure of the A1-A1 'line cross section, B1-B1' line cross section, C1-C1 'line cross section, and D1-D1' line cross section of a) is shown. FIG. 3 is a diagram for explaining the solar cell manufacturing method according to the first embodiment of the present invention in the order of steps by cross-sectional structures (FIGS. 3A to 3I) in main steps. FIG. 4 is a diagram for explaining a method for manufacturing a solar cell according to Embodiment 1 of the present invention, and is a diagram for explaining a process for plating an electrode layer of an n-type electrode in this solar cell. FIG. 5 is a diagram for explaining the solar cell according to Embodiment 1 of the present invention, and shows a wiring structure on a wiring board for taking out electric power from the solar cell. FIG. 6 is a diagram for explaining the solar cell according to Embodiment 1 of the present invention, and FIG. 6 (a) schematically shows an enlarged structure of the A5 portion in FIG. 5 and FIG. 6 (b). And FIG. 6C show the cross-sectional structures of the A6-A6 ′ line portion and the B6-B6 ′ line portion of FIG. 6A, respectively. FIG. 7 is a diagram for explaining the solar cell according to Embodiment 1 of the present invention, and shows a solar cell module in which the solar cell shown in FIG. 1 is attached to a wiring board. FIG. 8 is a plan view illustrating the solar cell according to Embodiment 1 of the present invention, and p of the solar cell in a portion corresponding to one solar cell of the solar cell module shown in FIG. 7 (A7 portion in FIG. 7). The positional relationship between the type electrode and the n-type electrode and the p-type wiring and the n-type wiring of the wiring board is shown. FIG. 9 is a diagram for explaining the solar cell according to Embodiment 1 of the present invention, and FIG. 9 (a), FIG. 9 (b), FIG. 9 (c), and FIG. 8 shows a cross-sectional structure of the solar cell module shown, that is, a cross-sectional structure taken along line A8-A8 ′, B8-B8 ′, C8-C8 ′, and D8-D8 ′ in FIG. . FIG. 10 is a diagram for explaining the solar cell according to Embodiment 1 of the present invention. The process before the solar cell shown in FIG. 1 is attached to the wiring board shown in FIG. 5 is treated as A1-A1 ′ in FIG. Line sectional view (FIG. 10A), B1-B1 ′ line sectional view (FIG. 10B), C1-C1 ′ line sectional view (FIG. 10C), D1-D1 ′ line sectional view (FIG. 10 (d)). FIG. 11 is a cross-sectional view illustrating the solar cell according to Embodiment 1 of the present invention, and FIG. 11 (a), FIG. 11 (b), FIG. 11 (c), and FIG. 8A, taken along the line A8-A8 ′, the line cross section B8-B8 ′, the line cross section C8-C8 ′ in the state where the solar cell shown in FIG. The structure of the D8-D8 'line cross section is shown. 12 is a cross-sectional view illustrating the solar cell according to Embodiment 1 of the present invention. FIGS. 12 (a), 12 (b), 12 (c), and 12 (d) are respectively the same as FIG. 8 is a cross section taken along line A8-A8 ′, a cross section taken along line B8-B8 ′, a cross section taken along line C8-C8 ′ in FIG. 8A in a state where the resin is softened by superimposing the solar cell on the wiring board shown in FIG. And the structure of the D8-D8 'line cross section is shown. FIG. 13 is a diagram for explaining the solar cell according to Embodiment 1 of the present invention, and shows another example of the structure of the wiring in the wiring board for taking out power from the solar cell. 14 is a plan view illustrating the solar cell according to Embodiment 1 of the present invention, and shows a solar cell module in which the solar cell shown in FIG. 1 is attached to the wiring board shown in FIG. FIG. 15 is a plan view illustrating a conventional solar cell, and schematically shows the structure of the back surface of the solar cell. FIG. 16 is a plan view for explaining a conventional solar cell, and shows a solar cell module formed by connecting a plurality of solar cells shown in FIG. FIG. 17 is a diagram for explaining a conventional solar cell of a wiring sheet type, and shows the arrangement of semiconductor regions on the back side of the substrate. FIG. 18 is a diagram for explaining a conventional solar cell of a wiring sheet type, and shows the arrangement of electrodes on the back side of the substrate. FIG. 19 is a diagram for explaining the structure of a wiring board on which a conventional solar cell of a wiring sheet type is mounted. FIG. 20 is a diagram showing a solar cell module in which a wiring sheet type conventional solar cell is attached to a wiring board.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram for explaining a solar cell according to Embodiment 1 of the present invention, and FIG. 1A shows the structure of the back surface of the solar cell.

This solar cell 100 includes a substantially square solar cell substrate 1 made of, for example, an n-type silicon substrate, and a p ⁺ type semiconductor region (diffusion region) having a comb-shaped planar pattern formed on the back surface of the n-type silicon substrate 1. 10 and an n ⁺ type semiconductor region (diffusion region) 20 having a comb-shaped planar pattern formed on the back surface of the n-type silicon substrate 1.

Here, the ^{p.sup. +} Type semiconductor region (diffusion region) 10 and the n.sup. ⁺ Type semiconductor region (diffusion region) 20 are arranged such that their respective comb-shaped planar patterns penetrate each other. That is, on the back surface of the solar cell substrate 1, the comb-tooth portion (part corresponding to the comb-shaped tooth) 10 b of the p ⁺ -type semiconductor region 10 and the comb-tooth portion (corresponding to the comb-shaped tooth) of the n-type semiconductor region 20. Portion) 20b are alternately arranged. comb teeth 10b of the p ⁺ -type semiconductor region 10, at one end, are connected together to p ⁺ -type comb back (portion to equivalent to the spine of the comb) of the semiconductor region 10 10a. The comb tooth 20b of the ^{n +} -type semiconductor region 20 is the other end of the ^{n +} -type semiconductor region 20, and integral to the ^{n +} -type comb back (portion to equivalent to the spine of the comb) of the semiconductor region 20 20a Connected. Here, the width of the comb tooth portion 10 b of the p ⁺ type semiconductor region 10 is wider than the width of the comb tooth portion 20 b of the n ⁺ type semiconductor region 20.

A p-type electrode (strip-shaped p-type electrode) 11 having a strip-shaped pattern corresponding to the planar pattern of the comb-tooth portion 10b is provided on the comb-tooth portion 10b of the p ⁺ -type semiconductor region 10. An n-type electrode (strip-shaped n-type electrode) 12 having a strip-shaped pattern corresponding to the planar pattern of the comb-tooth portion 20b is provided on the comb-tooth portion 20b of the n ⁺ -type semiconductor region 20.

  Moreover, since the solar cell 100 of this Embodiment 1 is a wiring sheet system, each strip | belt-shaped n-type electrode 12 and each strip | belt-shaped p-type electrode 11 are not electrically connected on the solar cell board | substrate 1, This solar An n-type wiring 112 for electrically connecting the individual band-shaped n-type electrodes 12 of the solar cell is formed on the wiring board 110 (see FIG. 5) on which the battery is mounted, and the individual band-shaped p-type electrodes 11 of the solar cell are formed. A p-type wiring 111 for electrically connecting the two is formed.

The planar pattern of the p ⁺ type semiconductor region 10 and the n ⁺ type semiconductor region 20 is not limited to the comb-shaped planar pattern, but is a striped pattern composed only of comb-tooth portions of the comb-shaped planar pattern. It may be. In this case, the planar pattern of the p ⁺ type semiconductor region and the n ⁺ type semiconductor region formed on the back surface side of the solar cell substrate is a plane in which strip-shaped p ⁺ type semiconductor regions and strip-shaped n ⁺ type semiconductor regions are alternately arranged. Any pattern including a pattern may be used.

  1 (d) and 1 (e) show an enlarged view of the G1 and G2 portions of FIG. 1 (a), and FIG. 1 (b) shows an E1-E1 ′ line portion of FIG. 1 (d). A cross-sectional structure is shown, and FIG. 1C shows a cross-sectional structure taken along line F1-F1 ′ in FIG.

  As shown in FIG. 1B, a texture structure 4 is formed on the surface (light receiving surface) of the n-type silicon substrate 1, and the light receiving surface is in a fine uneven state. In FIG. 1B, the texture structure 4 is indicated by a straight line. An antireflection film (for example, silicon nitride film) 2 is formed on the surface of the texture structure.

Then, on the p ⁺ type semiconductor region 10 b formed on the back surface of the n-type silicon substrate 1, firing as the p-type electrode 11 through a contact hole 31 formed in the passivation film (for example, silicon oxide film) 3. An electrode is formed. A fired electrode (electrode layer) 12a is formed on the n ⁺ type semiconductor region 20b formed on the back surface of the n-type silicon substrate 1 through a contact hole 32 formed in the passivation film 3. The fired electrode 12a is covered with a plating layer 12b. The fired electrode 12a and the surrounding plating layer 12b constitute a belt-like n-type electrode 12, and the belt-like n-type electrode 12 covers the plating layer 12b at a portion other than one end. An insulating resin film 15 is formed (see FIG. 1B), and the plating layer 12b is exposed at one end of the band-shaped n-type electrode 12 (see FIG. 1C).

  FIG. 2 is a view for explaining a cross-sectional structure of the electrode of the solar cell according to Embodiment 1 of the present invention. FIG. 2 (a), FIG. 2 (b), FIG. 2 (c), and FIG. The structures of the A1-A1 ′ line cross section, the B1-B1 ′ line cross section, the C1-C1 ′ line cross section, and the D1-D1 ′ line cross section of FIG. In FIG. 2, a specific cross-sectional structure of the solar cell substrate is omitted.

  That is, the strip-shaped p-type electrodes 11 and the strip-shaped n-type electrodes 12 are alternately arranged on the solar cell substrate 1, and the strip-shaped n-type electrode 12 is a fired electrode 12 a and a plating layer formed so as to cover it. 2b, the surface of the plating layer 12b is covered with an insulating resin film 15 except for one end A2 as shown in FIG. 2 (d). The layer 12b is exposed.

  When the insulating resin film 15 is supplied with energy in an uncured state, the viscosity rises from the uncured state to the first cured state, and then the viscosity is changed from the first cured state. Is once lowered to a softened state, and then the viscosity is increased again to have a second cured state in which the viscosity is higher than that of the first cured state. This first cured state is a state in which the viscosity is higher than the uncured state at room temperature, the adhesiveness is low, and the shape is retained.

  Next, the manufacturing method of the solar cell of Embodiment 1 will be described.

  FIG. 3 is a diagram for explaining an example of the manufacturing method of the solar cell according to Embodiment 1 of the present invention in the order of steps by cross-sectional structures (FIGS. 3A to 3I) in main steps.

  First, as shown to Fig.3 (a), an n-type silicon substrate is prepared as the board | substrate 1 of a solar cell. Here, a case where an n-type semiconductor substrate is used as the solar cell substrate 1 will be described, but the solar cell substrate may be a p-type semiconductor substrate. However, when a p-type semiconductor substrate is used, each of the semiconductor regions and electrodes described below has the conductivity type reversed.

  As the n-type silicon substrate 1, for example, a silicon wafer obtained by slicing a silicon ingot is used. Note that removal of slice damage to a silicon substrate created by slicing such a silicon ingot is performed by, for example, treating the surface of the silicon substrate after slicing with a mixed acid of hydrogen fluoride aqueous solution and nitric acid or an alkaline aqueous solution such as sodium hydroxide. This can be done by etching or the like.

  Further, the size and shape of the n-type silicon substrate 1 are not particularly limited. For example, from a practical aspect, a substantially rectangular surface having a thickness of 100 μm to 300 μm and a side length of 100 mm to 200 mm is used. What is necessary is just to have.

  Next, after a texture mask 7 made of a silicon oxide film is formed on the back surface of the n-type silicon substrate 1 by atmospheric pressure CVD, the n-type silicon substrate 1 is etched to make the light-receiving surface of the n-type silicon substrate 1 minute. The texture structure 4 is formed by processing into a rough surface (FIG. 3B). In FIG. 3, the texture structure 4 is indicated by a straight line for convenience.

  In this etching process, for example, as an etchant, a solution obtained by adding isopropyl alcohol to an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide is used. In the etching process, the etchant is, for example, 70 ° C. or higher and 80 ° C. or lower. To be heated. Such a texture structure 4 is not necessarily formed.

  Next, after removing the texture mask 7 using an aqueous hydrogen fluoride solution or the like, diffusion masks 8a and 8b made of a silicon oxide film are formed on the light-receiving surface and the back surface of the n-type silicon substrate 1 by an atmospheric pressure CVD method. An opening is formed in the diffusion mask 8b on the back surface by etching using an selectively applied etching paste (FIG. 3C).

Next, p-type impurities (boron) are diffused through the opening of diffusion mask 8b to form p ⁺ -type semiconductor region 10 on the back surface of n-type silicon substrate 1, and then diffusion masks 8a and 8b are masked. It removes using hydrogen fluoride (HF) aqueous solution etc. (FIG.3 (d)). FIG. 3D shows a comb tooth portion 10 b of the p ⁺ type semiconductor region 10.

Next, diffusion masks 9a and 9b are formed on the light-receiving surface and the back surface of n-type silicon substrate 1 in the same manner as diffusion masks 8a and 8b, and openings are formed in diffusion mask 9b on the back surface (FIG. 3 (e)). The n ⁺ type semiconductor region 20 is formed on the back surface of the n type silicon substrate 1 by vapor phase diffusion using POCl ₃ as a raw material, and then the diffusion masks 9a and 9b are removed with an aqueous hydrogen fluoride solution or the like (FIG. 3 ( f)). FIG. 3F shows the comb tooth portion 20 b of the n ⁺ type semiconductor region 20.

  Next, a passivation film 3 made of a silicon oxide film is formed on the back surface of the n-type silicon substrate 1 by thermal oxidation, and an antireflection film 2 made of a silicon nitride film is formed on the light-receiving surface of the n-type silicon substrate 1 by, for example, plasma CVD. Is formed (FIG. 3G).

Subsequently, the passivation film 3 is selectively removed by etching using an etching paste to form portions corresponding to the comb tooth portions 10b of the p ⁺ type semiconductor region 10 and the comb tooth portions 20b of the n ⁺ type semiconductor region 20. Contact holes 31 and 32 are formed (FIG. 3H).

  Next, after applying a conductive paste in a desired pattern to the back surface of the n-type silicon substrate 1, the conductive paste is baked to form a baked electrode 11 as a band-shaped p-type electrode and a band-shaped n-type electrode. An electrode (electrode layer) 12a is formed (FIG. 3 (i)).

  Here, the conductive paste used for forming the fired electrode is not particularly limited as long as it is used as an electrode of a solar cell. For example, a metal powder such as aluminum, silver, copper, nickel, etc. A conductive paste containing a frit, an organic vehicle, and an organic solvent can be used. As a preferred composition of the conductive paste, for example, metal powder is 60 to 80% by mass, glass frit is 1 to 10% by mass, organic vehicle is 1 to 15% by mass, and the other parts are included. It is an organic solvent. By setting it as such a composition, formation of the plating layer with respect to a baking electrode can be performed favorably. The conductive paste can be applied by known printing such as screen printing or an ink jet method.

  In the conductive paste firing step, when the paste material containing the above metal powder as a main component is fired at a temperature of 400 ° C. or higher in an oxidizing atmosphere furnace, the organic vehicle as the resin component burns, and the powder metal particles Since solid-phase metal diffusion occurs from the contact portion between the metal particles to form an integrated metal lump, it becomes conductive. Further, since the frit exists in a state dispersed in the paste material, it remains in a three-dimensional distribution other than the contact between the metal particles. As a result, the surface of the n-type silicon substrate 1 and the surface of the frit are sintered. Adhesiveness with the metal can be obtained.

  FIG. 4 is a diagram for explaining a method for manufacturing a solar cell according to Embodiment 1 of the present invention, and is a diagram for explaining a process for plating an n-type electrode in this solar cell.

  The solar cell substrate obtained by the treatment step shown in FIG. 3 is immersed in the activator. For example, it is preferable to immerse in an aqueous solution containing ammonium fluoride at room temperature for 1 minute. After the treatment with the activator, the plate is washed with water, and immersed in a container 6 filled with a plating solution 5, as shown in FIG.

  Here, the solar cell substrate 1 is held horizontally in the container 6, and the light L is irradiated to the light receiving surface side. However, the light irradiation method is not limited to such a method as long as the light receiving surface of the solar cell substrate 1 is exposed to light. When the solar cell substrate 1 is exposed to light, an internal electromotive force is generated, and metal ions present as cations in the plating solution are deposited on the negative electrode (n-type electrode) 12a, so that the plating layer 12b is formed. grow up.

  In this method, since the photovoltaic power of the solar cell is used, if the intensity of light hitting the solar cell substrate is increased, the growth rate of plating is also increased. As the plating solution, for example, an existing nickel plating solution containing nickel chloride, ammonium chloride, formaldehyde, and potassium hydroxide can be used.

For example, in a state where the solar cell 20 is irradiated with light equivalent to 1 SUN (usually 100 mW / cm ² ), the nickel plating solution is adjusted to pH 10 and the temperature is adjusted to 25 ° C. and immersed for 5 minutes to obtain a thickness of 10 μm. Of nickel was obtained.

  Thus, by using the electromotive force of the solar cell, only the fired electrode 12a constituting the n-type electrode 12 of the solar cell substrate 1 can be selectively plated very easily, and the cross-sectional area of the n-type electrode and The surface area can be increased.

  Thereafter, the plating layer 12b formed on the fired electrode 12a is covered with the insulating resin film 15 except for one end side portion of the fired electrode.

  For example, a method such as screen printing, dispenser coating, or inkjet coating can be used to form the insulating resin film 15.

  As this insulating resin film 15, when heated in an uncured liquid state, the viscosity increases and becomes a cured state (first cured state), and then the viscosity decreases and softens. This is preferable because it has a characteristic of increasing to a cured state (second cured state).

  Such a resin also has an insulation property that can prevent a short circuit between the electrodes on the back surface of the solar cell 100 and between the wirings of the wiring substrate 110 in the second cured state. In order to maintain the long-term reliability of the battery module, the battery module preferably has an adhesive strength that can maintain the mechanical connection strength between the solar cell substrate 1 and the wiring substrate 10.

  Further, it is also preferable to use a swelling type resin as the insulating resin 15. The swelling type resin is a mixture of an uncured and liquid resin and a fine particle resin. The thermal behavior of the swelling type resin is, for example, as follows. When the swelling type resin is heated above the glass transition temperature of the fine particle resin, the liquid resin enters between the molecules of the fine particle resin. As a result, the volume of the resin in the fine particle state is apparently expanded (swelled state) and the viscosity is increased, so that the apparently cured state (first cured state) is obtained. However, since the resin in the liquid state is uncured, when heated again, the resin in the liquid state that has entered between the molecules of the resin in the fine particle state can flow, and the viscosity is lowered to a softened state. When the heating is further continued, the resin in the liquid state is cured and becomes a cured state (second cured state).

  Next, a wiring board on which a solar cell is mounted will be described.

  5 and 6 are diagrams for explaining the solar cell according to Embodiment 1 of the present invention, and FIG. 5 shows the structure of the wiring in the wiring board for taking out electric power from this solar cell, and FIG. Fig. 6 schematically shows an enlarged view of the structure of the A5 portion in Fig. 5, and Fig. 6 (b) and Fig. 6 (c) show the A6-A6 'line portion and B6-B6 in Fig. 6 (a), respectively. 'The cross-sectional structure of the line portion is shown.

  The wiring board 110 shown in FIG. 5 has a plurality of mounting regions R5 for mounting the solar cell shown in FIG. Here, the wiring board 110 has a structure having 16 mounting regions R5, and the insulating sheet material 110a constituting the wiring substrate 110 includes a p-type wiring 111 and an n-type wiring for each mounting region R5. 112, and when the solar cell 100 is arranged in the mounting region R5, the p-type electrode 11 and the n-type electrode 12 of the solar cell face the p-type wiring 111 and the n-type wiring 112 of the wiring board. It has become.

  Here, one p-type wiring 111 and the other n-type wiring 112 in two mounting regions adjacent to each other in the extending direction of each wiring are connected by the first connection wiring 114a. One p-type wiring 111 and the other n-type wiring 112 in two mounting regions adjacent to each other along a side perpendicular to the direction in which each wiring extends on the substrate 110 are connected by a second connection wiring 114b. It is connected. Further, here, the wiring pattern of the wiring substrate 110 is formed so that the solar cells 100 arranged in each mounting region R5 are connected in series, and the p-type wiring 111 in the mounting region located at the head of the series connection is common. The n-type wiring 112 in the mounting region that is connected to the wiring 114c and located at the end of the series connection is connected to the common wiring 114d.

  The solar cell module 1000 (see FIG. 7) can be created by mounting the wiring sheet type solar cell 100 described in FIG. 1 on the wiring substrate 110 shown in FIG.

  7 shows this solar cell module 1000, and FIG. 8 shows a solar cell in a portion (A7 portion in FIG. 7) corresponding to one solar cell of the solar cell module shown in FIG. The positional relationship between the p-type electrode and the n-type electrode, and the p-type wiring and the n-type wiring of the wiring board is shown. 9 is a cross-sectional structure of the solar cell module shown in FIG. 8, that is, a cross section taken along line A8-A8 ′ in FIG. 8A (FIG. 9A), and a cross section taken along line B8-B8 ′ in FIG. )), C8-C8 ′ line cross section (FIG. 9C), and D8-D8 ′ line cross section (FIG. 9D).

  As can be seen from these figures, the p-type electrode 11 of the solar cell substrate 1 is arranged so as to overlap the p-type wiring 111 of the wiring substrate 110 over the entire length thereof, and the n-type electrode of the solar cell substrate 1 12 is arranged so as to overlap with the n-type wiring 112 of the wiring substrate 110 only at one end portion thereof.

  As shown in FIGS. 9A and 9C, the p-type electrode 11 of the solar cell substrate 1 is electrically connected to the p-type wiring 111 of the wiring substrate 110 by the conductive member 16b. As shown in FIGS. 9B and 9D, one n-type electrode 12 is electrically connected to the n-type wiring 112 of the wiring board 110 by a conductive member 16b on one end side thereof.

  And in the part which the p-type electrode 11 and the n-type electrode 12 adjoin, these electrodes are electrically insulated by the insulating resin film 15 and the insulating adhesive material 16a.

  Next, a method for creating a solar cell module will be described with reference to FIGS.

  FIG. 10 is a cross-sectional view taken along the line A1-A1 ′ of FIG. 1A (FIG. 10A) and the line B1-B1 ′ of FIG. 1A showing a process before the solar cell shown in FIG. 1 is attached to the wiring board shown in FIG. A cross-sectional view (FIG. 10B), a C1-C1 ′ line cross-sectional view (FIG. 10C), and a D1-D1 ′ line cross-sectional view (FIG. 10D) are shown.

  11 shows a cross section taken along the line A8-A8 ′ in FIG. 8A (FIG. 11A) and a cross section taken along the line B8-B8 ′ in the state where the solar cell shown in FIG. 1 is overlaid on the wiring substrate shown in FIG. (FIG. 11 (b)), C8-C8 ′ sectional view (FIG. 11 (c)), D8-D8 ′ sectional view (FIG. 11 (d)).

  FIG. 12 is a cross-sectional view taken along line A8-A8 ′ of FIG. 8A (FIG. 12A) and B8 in a state where the resin is softened by superimposing the solar cell shown in FIG. 1 on the wiring board shown in FIG. -B8 'sectional view (FIG. 12 (b)), C8-C8' sectional view (FIG. 12 (c)), D8-D8 'sectional view (FIG. 12 (d)).

  First, on the substrate 1 of the solar cell 100 shown in FIGS. 1 and 2, an adhesive (for example, Sn-Bi solder particles dispersed in an epoxy adhesive) in which a conductive adhesive 16b is mixed with an insulating adhesive 16a. A solder resin 16 is selectively applied (FIG. 10). At this time, the selective application of the solder resin 16 is performed by applying the solder resin to the solar cell substrate 1 by screen printing in a state where only the area where the solder resin is to be applied is exposed by the screen printing mask. Moreover, when performing this screen printing, the insulating resin film 15 already formed on the solar cell substrate 1 is in a semi-cured state.

  Specifically, by selective application of the solder resin, the solder resin 16 covers the p-type electrode 11 on the solar cell substrate 1 and the plating layer 12b on one end side of the n-type electrode 12 is exposed. It is applied to cover the part.

  Next, as shown in FIG. 11, the solar cell 100 shown in FIGS. 1 and 2 is arranged in the mounting region R5 of the wiring board 110 shown in FIGS. At this time, the p-type electrode 11 on the back surface side of the solar cell faces the p-type wiring 111 of the insulating sheet material 110 a of the wiring substrate 110, and one end side portion of the n-type electrode 12 is the insulating sheet material 110 a of the wiring substrate 110. The solar cell 100 is disposed on the wiring substrate 110 so as to face the n-type wiring 112.

  Next, as shown in FIG. 12, the insulating resin film 15 is softened and both substrates are pressurized, whereby the solar cell substrate 1 and the wiring substrate between the adjacent p-type electrode 11 and n-type electrode 12 are pressed. The softened insulating resin film 15 is filled in a region surrounded by the insulating sheet material 110a.

  Thereafter, the insulating adhesive 16a and the conductive adhesive 16b of the solder resin 16 are melted, and the conductive adhesive 16b is connected between the p-type electrode 11 and the p-type wiring 111 and one end side portion of the n-type electrode 12. As shown in FIG. 9, the p-type electrode 11 and the p-type wiring 111 are electrically connected to each other by the conductive adhesive 16 b, and one end side portion of the n-type electrode 12 is formed. And the n-type wiring 112 are electrically connected by the conductive adhesive 16b. Thereafter, the insulating adhesive 16a and the insulating resin film 15 are cured to fix the solar cell substrate 1 and the wiring substrate 110a. Thereby, the solar cell module 1000 shown in FIG. 7 is completed.

  As described above, in the solar cell 100 of the first embodiment, the p-type electrode 11 is formed by firing a conductive paste (for example, silver paste) containing a metal powder such as silver, and the n-type electrode 12 is formed of this conductive material. Since it is formed by baking paste and subsequent plating, patterning of n-type electrode and p-type electrode can be done by using an expensive resist or a complicated etching process with a mask for screen printing of conductive paste. It can be done easily without having to do.

  Further, the n-type electrode 12 was thickened by covering the fired electrode 12a with the plating layer 12b, and the p-type electrode 11 was thickened by covering with the solder resin (adhesive) 16. Because of the structure, it is possible to make the connection between the electrode on the back side of the solar cell substrate and the wiring of the wiring substrate highly reliable, and also suppress the use of expensive conductive resin, and the manufacturing cost of the solar cell Can be avoided.

  In addition, since the portion other than the one end portion of the n-type electrode 12 is covered with the insulating resin film 15, even if dust or the like adheres across the adjacent n-type electrode and p-type electrode, these polarities No short circuit occurs between different electrodes, and the pitch of the electrodes arranged on the back side of the solar cell substrate is narrowed while avoiding a short circuit between adjacent electrodes on the back side of the solar cell substrate Can do.

  Furthermore, when the solar cell 100 of the first embodiment is mounted on the wiring board, an insulating adhesive is provided so as to cover the exposed portion on one end side of the n-type electrode 12 on the back surface of the solar cell substrate 1 and the p-type electrode 11. Solder resin 16 including 16a and conductive adhesive 16b is selectively applied, and the solar cell substrate 1 is placed on the wiring substrate 110, and the p-type electrode 11 and the n-type electrode 12 are the p-type wiring 111 of the wiring substrate 110. Then, the conductive adhesive 16b is melted between the p-type electrode 11 and the p-type wiring 111 and the one end side portion of the n-type electrode 12 and the n-type. Since these electrodes and the wiring are electrically connected to each other by being agglomerated between the wiring 112, the fired electrode as the p-type electrode 11 and the p-type wiring 111 of the wiring board, which is not particularly formed with a plating layer, Connection is also reliable It can be.

  As a result, the connection between the electrode on the back side of the solar cell substrate and the wiring on the wiring substrate can be made highly reliable, and the pitch of the electrodes can be reduced while avoiding a short circuit due to adhesion of dust or the like. In addition, a significant increase in the manufacturing cost of the solar cell can be avoided.

  In the first embodiment, the solder resin 16 is applied to the back surface of the solar cell substrate before the solar cell is mounted on the wiring substrate, and the solar cell 100 does not have the solder resin 16. However, the solar cell covers the p-type electrode 11 on the solar cell substrate 1 with the solder resin 16 in the solar cell 100 of the first embodiment, and the plating layer 12b on one end side of the n-type electrode 12 is exposed. It is good also as a structure which covered the part which carried out.

  Moreover, in the said Embodiment 1, what formed so that the solar cell which has arrange | positioned the wiring pattern of p-type wiring and n-type wiring in each mounting area | region as a wiring board which mounts a solar cell was connected in series was shown. However, the wiring pattern of the wiring board on which the solar cell of Embodiment 1 is mounted is not limited to this.

  For example, FIG. 13 shows another example of the structure of the wiring in the wiring board for extracting power from the solar cell according to Embodiment 1 of the present invention.

14 shows a solar cell module in which the solar cell shown in FIG. 1 is attached to the wiring substrate shown in FIG. 13. The wiring substrate 120 shown in FIG. 13 has a mounting region R13 for mounting the solar cell shown in FIG. Have more than one. Here, the wiring board 120 has a structure having 16 mounting regions R13, and the insulating sheet material 120a constituting the wiring substrate 120 includes a p-type wiring 121 and an n-type wiring for each mounting region R13. 122 is provided, and when the solar cell 100 is disposed in the mounting region R13, each p-type electrode 11 of the solar cell faces the p-type wire 121 of the wiring substrate, and one end side of each n-type electrode 12 of the solar cell. The portion faces the n-type wiring 122 of the wiring board.

  Here, the p-type wiring 121 and the n-type wiring 122 of the wiring board 120 are the same as the p-type wiring 111 and the n-type wiring 112 of the wiring board 110 shown in FIG. 5, and are adjacent to each other in the extending direction of each wiring. One p-type wiring 121 in the two mounting regions and the other n-type wiring 122 are connected by a first connection wiring 124a, and are orthogonal to the direction in which each wiring extends on the wiring board 120. The p-type wirings 121 in the four mounting regions adjacent to each other along one side are commonly connected by a common wiring 124b. The n-type wirings 122 in the four mounting regions adjacent to each other along the other side of the wiring board 120 that is orthogonal to the direction in which each wiring extends are commonly connected by a common wiring 124b.

  The above-described wiring sheet type solar cell 100 of FIG. 1 is mounted on the wiring substrate 120 shown in FIG. 13, and the solar cell module 2000 shown in FIG. 14 can be created.

  This solar cell module 2000 includes four series connection bodies formed by connecting four solar cells in series, and has a configuration in which these four series connection bodies are connected in parallel.

  As mentioned above, although this invention has been illustrated using preferable embodiment of this invention, this invention should not be limited and limited to this embodiment. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  INDUSTRIAL APPLICABILITY In the field of a solar cell and a manufacturing method thereof, and a solar cell module and a manufacturing method thereof, the connection between the electrode on the back surface side of the solar cell substrate and the wiring of the wiring substrate can be made highly reliable. Moreover, a solar cell capable of reducing the pitch of the electrodes disposed on the back surface side of the solar cell substrate while avoiding a short circuit between adjacent electrodes on the back surface side of the solar cell substrate, a method for manufacturing the solar cell, and the sun A battery module and a manufacturing method thereof can be realized.

1 Solar cell substrate (n-type silicon substrate)
2 Antireflection film (silicon nitride film)
3 Passivation film (silicon oxide film)
4 Texture structure 10 p ⁺ type semiconductor region (diffusion region)
10a, 20a Comb back part 10b, 20b Comb tooth part 11 p-type electrode (band-like p-type electrode)
12 n-type electrode (band n-type electrode)
12a Firing electrode 12b Plating electrode 15 Insulating resin film 16 Solder resin (conductive resin film)
16a Insulating adhesive 16b Conductive adhesive 20 n ⁺ type semiconductor region (diffusion region)
31, 32 Contact hole 100 Solar cell 110, 120 Wiring substrate 110a, 120a Insulating sheet material 111, 121 P-type wiring 112, 122 n-type wiring 114a First connection wiring 114b Second connection wiring 124a Connection wiring 114c, 114d, 124b Common wiring 1000, 2000 Solar cell module R5, R13 Mounting area

Claims (16)

A first conductive type semiconductor substrate, a first main surface of the first conductive type semiconductor substrate as a light-receiving surface, and a second main surface opposite to the first main surface of the first conductive type semiconductor substrate; A solar cell in which the first conductive semiconductor regions and the second conductive semiconductor regions in a band shape are alternately arranged,
A first electrode formed on the first conductivity type semiconductor region so as to extend along the region;
A second electrode formed on the second conductivity type semiconductor region so as to extend along the region;
The first electrode includes an electrode layer formed so as to be in contact with the first conductivity type semiconductor region, and a plating layer formed so as to cover the electrode layer, and the plating layer is included in the first electrode. A solar cell having a structure coated with an insulating resin film except for one end portion of the solar cell. The solar cell according to claim 1,
The first electrode is a solar cell having a structure in which one end side portion of the first electrode of the plating layer is covered with an adhesive including a conductive adhesive and an insulating adhesive. The solar cell according to claim 2,
The second electrode includes an electrode layer formed to be in contact with the second conductivity type semiconductor region,
A solar cell having a structure in which an electrode layer constituting the second electrode is covered with an adhesive including a conductive adhesive and an insulating adhesive. The solar cell according to claim 3,
The electrode layer which comprises the said 1st electrode and this 2nd electrode is a solar cell which is a baking electrode layer formed by baking the electrically conductive paste containing metal powder. The solar cell according to claim 4,
The conductive paste contains silver as a metal powder,
The solar cell, wherein the fired electrode layer is a silver electrode layer. The solar cell according to any one of claims 2 to 5,
After the insulating resin film covering the plated layer of the first electrode is supplied with energy in an uncured state, the viscosity rises from the uncured state and becomes the first cured state, From the first cured state, the viscosity is once lowered to be in a softened state, and then the viscosity is increased again to be in a second cured state in which the viscosity is higher than the first cured state. And
The insulating adhesive material which comprises the said adhesive material is a solar cell which has a property which a viscosity rises from the said uncured state and becomes a cured state by supplying energy to an uncured state. The solar cell according to claim 6,
The first cured state is a solar cell in which the viscosity is higher than that in an uncured state at normal temperature, the adhesiveness is low, and the shape is retained. The solar cell according to any one of claims 1 to 7,
The band-shaped second conductive semiconductor region is a solar cell whose width is wider than the width of the band-shaped first conductive semiconductor region. The solar cell according to any one of claims 1 to 8,
The first conductive semiconductor substrate is an n-type silicon substrate;
The second conductivity type semiconductor region is a p-type diffusion region in which boron is diffused,
The first conductivity type semiconductor region is a solar cell, which is an n-type diffusion region in which phosphorus is diffused. A first conductive type semiconductor substrate, a first main surface of the first conductive type semiconductor substrate as a light-receiving surface, and a second main surface opposite to the first main surface of the first conductive type semiconductor substrate; A method of manufacturing a solar cell in which first conductive semiconductor regions and strip-shaped second conductive semiconductor regions are alternately arranged,
Forming an electrode layer on each of the first conductive semiconductor region and the second conductive semiconductor region so as to extend along these regions;
Forming a plating layer selectively only on the electrode layer on the first conductivity type semiconductor region;
Covering the plating layer formed on the electrode layer on the first conductivity type semiconductor region with an insulating resin film except for one end side portion of the electrode layer on the first conductivity type semiconductor region, Battery manufacturing method. In the manufacturing method of the solar cell of Claim 10,
A portion of the plating layer formed on the electrode layer in the first conductivity type semiconductor region, which is not covered with the insulating resin film, and the electrode layer on the second conductivity type semiconductor region are electrically conductive with an insulating adhesive. The manufacturing method of a solar cell which has the process coat | covered with the adhesive material containing an adhesive material. A solar cell module in which one or more solar cells are mounted on a wiring board,
The solar cell is
A first conductive type semiconductor substrate, a first main surface of the first conductive type semiconductor substrate as a light-receiving surface, and a second main surface opposite to the first main surface of the first conductive type semiconductor substrate; The first conductivity type semiconductor regions and the band-like second conductivity type semiconductor regions are alternately arranged,
A first electrode formed on the first conductivity type semiconductor region so as to extend along the region;
A second electrode formed on the second conductivity type semiconductor region so as to extend along the region;
The first electrode includes an electrode layer formed so as to be in contact with the first conductivity type semiconductor region, and a plating layer formed so as to cover the electrode layer, and the plating layer is included in the first electrode. It has a structure coated with an insulating resin film except for one end side of
The wiring board is
A first wiring connected to the first electrode, arranged to face each first electrode of the solar cell mounted on the wiring board, in each mounting region for mounting the solar cell;
In each mounting area for mounting the solar cell, the second wiring is disposed so as to face the second electrode of the solar cell mounted on the wiring board, and connected to the second electrode,
The solar cell module, wherein the first electrode is electrically connected to the first wiring at one end side portion thereof. The solar cell module according to claim 12, wherein
The first electrode and the first wiring are conductive adhesives constituting the solder resin obtained by melting the solder resin applied to the surface of the plating layer in one end side portion of the first electrode. A solar cell module connected by In the solar cell module according to claim 12 or 13,
The second electrode and the second wiring are connected by a conductive adhesive constituting the solder resin obtained by melting the solder resin applied to the surface of the electrode layer constituting the second electrode. The solar cell module. The solar cell module according to claim 14, wherein
The connecting portion between the second electrode and the second wiring is an insulating adhesive that constitutes a solder resin applied to the surface of the electrode layer constituting the second electrode with respect to the first electrode. And a solar cell module that is electrically insulated by an insulating resin film that covers the plating layer of the first electrode. A method of manufacturing a solar cell module by mounting one or more solar cells on a wiring board,
The solar cell is
A first conductive type semiconductor substrate, a first main surface of the first conductive type semiconductor substrate as a light-receiving surface, and a second main surface opposite to the first main surface of the first conductive type semiconductor substrate; The first conductivity type semiconductor regions and the band-like second conductivity type semiconductor regions are alternately arranged,
A first electrode formed on the first conductivity type semiconductor region so as to extend along the region;
A second electrode formed on the second conductivity type semiconductor region so as to extend along the region;
The first electrode includes an electrode layer formed so as to be in contact with the first conductivity type semiconductor region, and a plating layer formed so as to cover the electrode layer, and the plating layer is included in the first electrode. It has a structure coated with an insulating resin film except for one end side of
The second electrode includes an electrode layer formed in contact with the second conductivity type semiconductor region,
The wiring board is
A first wiring disposed so as to face the first electrode of the solar cell when the solar cell is mounted on the wiring board in each mounting region for mounting the solar cell;
Each mounting region for mounting the solar cell includes a second wiring arranged so as to face the second electrode of the solar cell when the solar cell is mounted on the wiring board.
The method includes insulating bonding between a portion of the plating layer formed on the electrode layer in the first conductivity type semiconductor region and not covered with the insulating resin film, and the electrode layer on the second conductivity type semiconductor region. Coating with an adhesive comprising a material and a conductive adhesive;
Placing the solar cell on the wiring substrate so that the first and second electrodes of the solar cell face the first and second wirings of the wiring substrate;
A portion of the plating layer formed on the electrode layer of the first electrode by heat treatment of the insulating resin film and the adhesive material is bonded to the first wiring and a portion not covered with the insulating resin film. And connecting the electrode layer of the second electrode and the second wiring with the conductive adhesive contained in the adhesive. Production method.

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