WO2021140897A1

WO2021140897A1 - Method for manufacturing solar cell and solar cell

Info

Publication number: WO2021140897A1
Application number: PCT/JP2020/047682
Authority: WO
Inventors: 正典兼松; 訓太吉河; 小西　克典
Original assignee: 株式会社カネカ
Priority date: 2020-01-08
Filing date: 2020-12-21
Publication date: 2021-07-15
Also published as: JPWO2021140897A1; JP7539415B2

Abstract

To provide a method for manufacturing a solar cell that can manufacture a highly efficient solar cell at low cost. A method for manufacturing a solar cell according to an aspect of the present invention comprises the steps of: forming a first semiconductor layer and a second semiconductor layer on the rear surface of a semiconductor substrate; laminating a transparent electrode on the rear surface side of the semiconductor substrate to cover the first semiconductor layer and the second semiconductor layer; forming a first base electrode and a second base electrode by laminating a first conductive paste; forming a first insulating part and a second insulating part arranged in matrix form by laminating an insulating paste; forming a first high electrode and a second high electrode by laminating a second conductive paste; selectively removing the transparent electrode by etching using, as masks, the first base electrode, the second base electrode, the first insulating part, the second insulating part, the first high electrode, and the second high electrode; and connecting the first high electrode and the second high electrode via a first wiring material and a second wiring material.

Description

Solar cell manufacturing method and solar cells

The present invention relates to a solar cell manufacturing method and a solar cell.

A plurality of strip-shaped first semiconductor layers and second semiconductor layers alternately formed on the back surface of the semiconductor substrate, and a plurality of strip-shaped first base electrodes and second layers laminated on the first semiconductor layer and the second semiconductor layer, respectively. It is arranged so as to bridge between the base electrode, the plurality of first raised electrodes and the second raised electrodes stacked alternately on the first base electrode and the second base electrode, and the plurality of first raised electrodes. A back contact type solar cell including a first wiring material and a second wiring material arranged so as to bridge between a plurality of second raised electrodes is known.

In such a solar cell, in order to prevent a short circuit between the first base electrode and the second wiring material and a short circuit between the second base electrode and the first wiring material, it intersects with the second wiring material of the first base electrode. There is also known a configuration in which an insulating material is laminated in a region to be formed and a region intersecting the first wiring material of the second base electrode (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-3724

In the above-mentioned solar cell, the base electrode and the raised electrode can be formed relatively easily by screen-printing a material such as silver paste. Further, an insulating material for preventing a short circuit between the base electrode and the wiring material can also be arranged by screen printing. In order to efficiently collect current from the semiconductor layer, it is desirable to increase the width of the base electrode. However, since the silver paste is relatively expensive, forming a wide base electrode with the silver paste has the disadvantage of increasing the cost of the solar cell. Therefore, it is an object of the present invention to provide a solar cell manufacturing method capable of manufacturing a highly efficient solar cell at a low cost and an inexpensive and highly efficient solar cell.

In the solar cell manufacturing method according to one aspect of the present invention, a first semiconductor layer and a second semiconductor layer extending in the first direction are alternately formed on the back surface of the semiconductor substrate in the second direction intersecting the first direction, respectively. The step, the step of laminating a transparent electrode on the back surface side of the semiconductor substrate so as to cover the first semiconductor layer and the second semiconductor layer, and the step of laminating the first conductive paste, the first of the transparent electrodes. A first base electrode extending in the first direction is formed in a region laminated on the semiconductor layer, and a second base electrode extending in the first direction is formed in a region laminated on the second semiconductor layer of the transparent electrode. By laminating the insulating paste, the transparent electrode and the first base electrode are arranged so as to be included in the first semiconductor layer in a plan view, respectively, in the first direction and the second. A plurality of first insulating portions arranged in a matrix in the direction are formed, and are arranged across the transparent electrode and the second base electrode so as to be included in the second semiconductor layer in a plan view, respectively, in the first direction. The first base electrode is formed by forming a plurality of second insulating portions arranged in a matrix alternately arranged with the first insulating portion in the second direction and laminating the second conductive paste. The step of forming the first raised electrode in the region where the first insulating portion is not laminated and forming the second raised electrode in the region where the second insulating portion of the second base electrode is not laminated, and the first step. The transparent electrode is selectively removed by etching using the 1 base electrode, the second base electrode, the first insulating portion, the second insulating portion, the first raised electrode, and the second raised electrode as masks. The step includes a step of connecting between the first raised electrodes and the second raised electrodes by the first wiring material and the second wiring material extending in the second direction, respectively.

In the solar cell manufacturing method according to the above aspect, after the transparent electrode is selectively removed, the resin contained in the first base electrode, the second base electrode, the first insulating portion, and the second insulating portion is heated. May be further provided with a step of exuding.

In the solar cell manufacturing method according to the above aspect, the first conductive paste, the insulating paste, and the second conductive paste may be laminated by screen printing, respectively.

A solar cell according to another aspect of the present invention has a plurality of first semiconductor layers alternately provided on a semiconductor substrate and the back surface of the semiconductor substrate in a second direction extending in the first direction and intersecting the first direction. And a plurality of second semiconductor layers, a plurality of first transparent electrodes laminated so as to extend in the first direction on each of the first semiconductor layers, and each of the second semiconductor layers so as to extend in the first direction. A plurality of second transparent electrodes to be laminated, a plurality of first base electrodes laminated so as to extend in the first direction on each of the first transparent electrodes, and each of the second transparent electrodes in the first direction. A plurality of second base electrodes stacked so as to extend and a plurality of second base electrodes are arranged in a matrix at intervals in the first direction and the second direction so as to be laminated on a plurality of portions of the first base electrodes. The first raised electrode and the first raised electrode are alternately spaced in the first direction and the second direction so as to be laminated on the plurality of first raised electrodes and a plurality of portions of the second base electrode. The portion between the plurality of second raised electrodes arranged in a matrix and the first raised electrode of each of the first base electrodes is covered so as to be included in the first semiconductor layer in a plan view. It covers a portion between the first transparent electrode, the first insulating portion laminated over the first base electrode, and the second raised electrode of each of the second base electrodes, and each covers the portion between the first transparent electrode and the second raised electrode in a plan view. A second insulating portion laminated over the second transparent electrode and the second base electrode so as to be included in the second semiconductor layer, and arranged on the back surface side of the first raised electrode and the first insulating portion. , The first wiring material that electrically connects between the first raised electrodes, and the second raised electrode and the second raised electrode are arranged on the back surface side of the second insulating portion, and are electrically connected between the second raised electrodes. A second wiring material to be connected to the object is provided.

In the solar cell according to the above aspect, the first insulating portion and the second insulating portion are separated from the first semiconductor layer and the second semiconductor layer, and the width of the first insulating portion in the second direction is The width of the first transparent electrode may be larger than the width of the second direction, and the width of the second insulating portion in the second direction may be larger than the width of the second transparent electrode in the second direction.

In the solar cell according to the above aspect, the width of the region where the first insulating portion of the first base electrode is laminated and the portion where the second insulating portion of the second base electrode is laminated is the width in the second direction. The width of the region where the first raised electrode of the first base electrode is laminated and the portion of the second base electrode where the second raised electrode is laminated is smaller than the width in the second direction, and the first insulation is provided. The width of the portion and the second insulating portion in the second direction is such that the region where the first raised electrode of the first base electrode is laminated and the second raised electrode of the second base electrode are laminated. It may be substantially equal to the width of the portion in the second direction.

In the solar cell according to the above aspect, the side surfaces of the first transparent electrode and the second transparent electrode may be at least partially covered with resin.

According to the present invention, it is possible to provide a solar cell manufacturing method capable of manufacturing a highly efficient solar cell at low cost and an inexpensive and highly efficient solar cell.

It is a back view which shows the structure of the solar cell which concerns on one Embodiment of this invention. FIG. 5 is a cross-sectional view taken along the line AA of the solar cell of FIG. It is a back view which shows the state which removed some components of the solar cell of FIG. It is a flowchart which shows the procedure of the solar cell manufacturing method which concerns on one Embodiment of this invention. It is a schematic cross-sectional view which shows one process of the solar cell manufacturing method of FIG. It is a schematic cross-sectional view which shows the next process of FIG. 5 of the solar cell manufacturing method of FIG. It is a schematic cross-sectional view which shows the next process of FIG. 6 of the solar cell manufacturing method of FIG. It is a schematic cross-sectional view which shows the next process of FIG. 7 of the solar cell manufacturing method of FIG. It is a schematic cross-sectional view which shows the next process of FIG. 8 of the solar cell manufacturing method of FIG. It is a schematic cross-sectional view which shows the next process of FIG. 9 of the solar cell manufacturing method of FIG. It is a schematic cross-sectional view which shows the next process of FIG. 10 of the solar cell manufacturing method of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic back view showing the configuration of the solar cell 1 according to the embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of the solar cell 1 of FIG. The hatching in FIG. 1 is attached to make it easier to distinguish each component, and does not mean a cross section. In addition, for convenience, hatching, member codes, and the like may be omitted, but in such cases, other drawings shall be referred to. Further, the dimensions of the various members in the drawings are adjusted for convenience so that they can be easily seen.

The solar cell 1 is a so-called heterojunction back contact type solar cell. The solar cell 1 includes a semiconductor substrate 11, a first semiconductor layer 21 and a second semiconductor layer 22 arranged on the back surface of the semiconductor substrate 11 (a surface opposite to the incident surface of light), a first semiconductor layer 21, and the like. The first transparent electrode 31 and the second transparent electrode 32 arranged on the back surface side of the second semiconductor layer 22, and the first base arranged on the back surface side of the first transparent electrode 31 and the second transparent electrode 32, respectively. The electrodes 41 and the second base electrode 42, the first raised electrode 51 and the second raised electrode 52 arranged on the first base electrode 41 and the second base electrode 42, respectively, and the first base electrode 41 and the first Between the first insulating portion 61 and the second insulating portion 62 that cover the region where the first raised electrode 51 and the second raised electrode 52 of the two base electrodes 42 are not arranged, and between the first raised electrode 51 and the second. The first covering portion 81 and the first covering portion 81 and the second covering material 71 and the second wiring material 72 connecting between the two raised electrodes 52, respectively, and the side surfaces of the first transparent electrode 31 and the second transparent electrode 32 are partially covered. The two covering portions 82 are provided.

The semiconductor substrate 11 is formed of a crystalline silicon material such as single crystal silicon or polycrystalline silicon. The semiconductor substrate 11 is, for example, an n-type semiconductor substrate in which a crystalline silicon material is doped with an n-type dopant. Examples of the n-type dopant include phosphorus (P). The semiconductor substrate 11 functions as a photoelectric conversion substrate that absorbs incident light from the light receiving surface side to generate optical carriers (electrons and holes). By using crystalline silicon as the material of the semiconductor substrate 11, a relatively high output (stable output regardless of the illuminance) can be obtained even when the dark current is relatively small and the intensity of the incident light is low.

The first semiconductor layer 21 and the second semiconductor layer 22 have different conductive types from each other. As an example, the first semiconductor layer 21 is formed of a p-type semiconductor, and the second semiconductor layer 22 is formed of an n-type semiconductor. The first semiconductor layer 21 and the second semiconductor layer 22 can be formed of, for example, an amorphous silicon material containing a dopant that imparts a desired conductive type. Examples of the p-type dopant include boron (B), and examples of the n-type dopant include phosphorus (P) described above.

The first semiconductor layer 21 and the second semiconductor layer 22 are each formed in a band shape extending in the first direction. In the solar cell 1, the plurality of first semiconductor layers 21 and the plurality of second semiconductor layers 22 are alternately provided in the second direction intersecting the first direction. The first semiconductor layer 21 and the second semiconductor layer 22 are preferably arranged so as to cover substantially the entire surface of the semiconductor substrate 11.

The first transparent electrode 31 is laminated on each of the first semiconductor layers 21 so as to extend in the first direction, and the second transparent electrode 32 is laminated on each of the second semiconductor layers 22 so as to extend in the first direction. The first transparent electrode 31 and the second transparent electrode 32 are thin layers that collect current from the first semiconductor layer 21 and the second semiconductor layer 22 and connect to the first base electrode 41 and the second base electrode 42. Further, the first transparent electrode 31 and the second transparent electrode 32 have adhesiveness caused by a difference in material between the first semiconductor layer 21 and the second semiconductor layer 22 and the first base electrode 41 and the second base electrode 42. It functions as an intermediate layer that prevents a decrease and an increase in electrical resistance at the interface.

The first transparent electrode 31 and the second transparent electrode 32 have a width smaller than that of the first semiconductor layer 21 and the second semiconductor layer 22 in the second direction so as not to come into contact with each other, and the first semiconductor layer 21 and the first semiconductor layer 21 in the first direction. The two semiconductor layers 22 are laminated over substantially the entire length. The width of the first transparent electrode 31 and the second transparent electrode 32 changes in the second direction corresponding to the first base electrode 41 and the second base electrode 42, which will be described later, and the first insulating portion 61 and the second insulating portion 62. ..

The first transparent electrode 31 and the second transparent electrode 32 can be formed of the same material. Examples of the material forming the first transparent electrode 31 and the second transparent electrode 32 include ITO (Indium Tin Oxide) and zinc oxide (ZnO). Further, the first transparent electrode 31 and the second transparent electrode 32 are laminated in a wider area than the first base electrode 41 and the second base electrode 42, which will be described later, so that the first base electrode 41 and the second base electrode 42 are laminated. The current collecting capacity can be improved.

The first base electrode 41 is laminated on each of the first transparent electrodes 31 so as to extend in the first direction, and the second base electrode 42 is laminated on each of the second transparent electrodes 32 so as to extend in the first direction. The first base electrode 41 and the second base electrode 42 collect electric power via the first transparent electrode 31 and the second transparent electrode 32.

FIG. 3 shows the solar cell 1 in a state where the first raised electrode 51, the second raised electrode 52, the first wiring material 71, and the second wiring material 72 are removed. As shown in the figure, the width of the portion in which the first raised electrode 51 and the second raised electrode 52 of the first base electrode 41 and the second base electrode 42 are laminated is the portion between them, that is, the first. It is larger than the width in the second direction at the portion where the first insulating portion 61 and the second insulating portion 62 of the base electrode 41 and the second base electrode 42 are laminated.

More specifically, the width of the first base electrode 41 and the second base electrode 42 in the second direction in the portion where the first raised electrode 51 and the second raised electrode 52 are laminated is the width of the first raised electrode 51 and the second raised electrode 42. 2 The height of the raised electrode 52 and a sufficient connection area between the first wiring material 71 and the second wiring material 72 are set so as to be secured. Further, the width in the second direction in the region where the first raised electrode 51 and the second raised electrode 52 of the first base electrode 41 and the second base electrode 42 are laminated is the first transparent electrode 31 or the second transparent electrode. It may be slightly larger than the width of 32 in the second direction. That is, the first base electrode 41 and the second base electrode 42 are connected to the first semiconductor layer 21 and the second semiconductor layer 22 at the ends in the second direction without passing through the first transparent electrode 31 and the second transparent electrode 32. It may have regions facing each other with a gap.

Further, a region between the first raised electrode 51 of the first base electrode 41 and the second base electrode 42 or between the second raised electrode 52, that is, the first insulation of the first base electrode 41 and the second base electrode 42. The width of the portion in which the portion 61 and the second insulating portion 62 are laminated in the second direction is preferably the minimum necessary size that can ensure conductivity. Considering the misalignment of each component, the width of the first base electrode 41 and the second base electrode 42 is set at both ends of the region covered by the first insulating portion 61 and the second insulating portion 62 in the first direction. It is more preferable that the size is reduced only in the region to be excluded.

The first base electrode 41 and the second base electrode 42 can be formed from a conductive paste containing conductive particles and a resin binder. As a specific conductive paste, a silver paste can be typically mentioned. By using the conductive paste, the first base electrode 41 and the second base electrode 42 having a sufficient thickness so that the electric resistance can be reduced can be formed at a relatively low cost.

The first raised electrodes 51 are arranged in a matrix at intervals in the first direction and the second direction so as to be laminated on a plurality of portions of the respective first base electrodes 41, and the second raised electrodes 52 are arranged in a matrix. , The first raised electrode 51 and the first raised electrode 51 are arranged in a matrix at intervals so as to be laminated on a plurality of portions of each second base electrode 42 in the first direction and the second direction. The first raised electrode 51 is interposed between the first base electrode 41 and the first wiring material 71 to separate the first wiring material 71 from the second base electrode 42. The second raised electrode 52 is interposed between the second base electrode 42 and the second wiring material 72 to separate the second wiring material 72 from the first base electrode 41.

The first raised electrode 51 and the second raised electrode 52 can be formed from a conductive paste such as silver paste, in order to improve the adhesiveness with the first base electrode 41 and the second base electrode 42. In addition, it is preferably formed of the same material as the first base electrode 41 and the second base electrode 42.

The heights of the first raised electrode 51 and the second raised electrode 52 are set to the first insulating portion 61 and the second insulating portion 62 so that reliable contact with the first wiring material 71 and the second wiring material 72 can be obtained. It is preferably sufficiently larger than the height of. The width of the first raised electrode 51 and the second raised electrode 52 in the second direction is substantially equal to the width of the laminated region of the first base electrode 41 and the second base electrode 42 in order to increase the height efficiently. Is preferable. The length of the first raised electrode 51 and the second raised electrode 52 in the first direction is such that the first raised electrode 51 and the second wiring material 72 are short-circuited and the second raised electrode 52 and the first wiring material 71 are short-circuited. In order to prevent a short circuit with the above, it is preferable that the distance between the first raised electrode 51 and the second raised electrode 52 is smaller than the distance in the first direction so as not to overlap when viewed from the second direction.

The first insulating portion 61 covers the portion between the first raised electrodes 51 of each of the first base electrodes 41, and the first transparent electrode 31 and the first base are included in the first semiconductor layer 21 in a plan view. It is laminated across the electrodes 41. The second insulating portion 62 covers the portion between the second raised electrodes 52 of each of the second base electrodes 42, and the second transparent electrode 32 and the second base are included in the second semiconductor layer 22 in a plan view. It is laminated over the electrodes 42. The first insulating portion 61 and the second insulating portion 62 may be laminated on the ends of the first raised electrode 51 and the second raised electrode 52 in the first direction. The first insulating portion 61 and the second insulating portion 62 ensure the insulation between the first wiring material 71 and the second base electrode 42 and the insulation between the second wiring material 72 and the first base electrode 41. Further, since the first insulating portion 61 and the second insulating portion 62 particularly cover the portions of the first base electrode 41 and the second base electrode 42 having a small cross-sectional area to prevent contact with moisture or the like, the first insulating portion 61 and the second insulating portion 62 are first. The portion of the base electrode 41 and the second base electrode 42 having a small cross-sectional area is corroded and the conductivity is greatly impaired, and the first transparent electrode 31 and the second transparent electrode of the first base electrode 41 and the second base electrode 42 are greatly impaired. It is possible to prevent peeling from 32.

The width of the first insulating portion 61 and the second insulating portion 62 in the second direction is the portion where the first raised electrode 51 and the second raised electrode 52 of the first base electrode 41 and the second base electrode 42 are laminated. It is preferable that the width is substantially equal to the width in the second direction. As a result, the widths of the first transparent electrode 31 and the second transparent electrode 32 in the second direction can be made substantially constant, so that the widths of the first transparent electrode 31 and the second transparent electrode 32 in the second direction are increased. Therefore, the current collecting resistance can be made smaller. Further, the lengths of the first insulating portion 61 and the second insulating portion 62 in the first direction are such that the first raised electrode 51 and the second wiring material 72 are short-circuited and the second raised electrode 52 and the first wiring material 71 are short-circuited. In order to prevent a short circuit with the first raised electrode 51, it is preferable that the length of the first raised electrode 51 and the second raised electrode 52 is larger than the length in the first direction.

The first insulating portion 61 and the second insulating portion 62 can be formed from a paste-like material having insulating properties. As a material for forming the first insulating portion 61 and the second insulating portion 62, for example, a thermosetting resin composition containing an epoxy resin or the like as a main component can be used.

The first wiring material 71 is arranged on the back surface side of the first raised electrode 51 and the first insulating portion 61, electrically connects between the first raised electrodes 51, and the second wiring material 72 is the second. It is arranged on the back surface side of the raised electrode 52 and the second insulating portion 62, and electrically connects the second raised electrode 52.

The first wiring material 71 and the second wiring material 72 can be formed of, for example, a conductor such as a copper wire. The first wiring material 71 and the second wiring material 72 and the first raised electrode 51 and the second raised electrode 52 can be connected by, for example, solder, a conductive adhesive, or the like. As the first wiring material 71 and the second wiring material 72, a metal wire coated with solder for connecting the outer surface to the first raised electrode 51 and the second raised electrode 52 may be used.

The first covering portion 81 and the second covering portion 82 cover the end faces of the first transparent electrode 31 and the second transparent electrode 32 on both sides in the second direction. The first coating portion 81 and the second coating portion 82 can be formed by exuding the resin components of the first base electrode 41 and the second base electrode 42, and the first insulating portion 61 and the second insulating portion 62. .. By forming the first coating portion 81 and the second coating portion 82, the first transparent electrode 31 and the second transparent electrode 32 can be formed even when water has penetrated into the solar cell module formed by using the solar cell 1. It can be protected and the deterioration of the performance of the solar cell 1 can be suppressed.

As described above, in the solar cell 1, the first base electrode 41, the second base electrode 42, the first raised electrode 51, and the second raised electrode 52 for collecting electricity are formed with a vacuum facility required. Since it can be formed by printing and firing a paste-like material without using technology, it can be manufactured at a relatively low cost. Further, the solar cell 1 includes a first transparent electrode 31 and a second transparent electrode 32 for extracting electric power from the first semiconductor layer 21 and the second semiconductor layer 22, so that the first base electrode 41 and the second base electrode 42 can be separated from each other. The width of the portion between the first raised electrode 51 and the second raised electrode 52 can be reduced. As a result, the amount of the relatively expensive conductive paste used is reduced, so that the solar cell 1 can be manufactured with high efficiency and at a relatively low cost.

Next, a method for manufacturing the solar cell 1 will be described. The solar cell 1 can be manufactured by the solar cell manufacturing method shown in FIG. The solar cell manufacturing method of FIG. 4 is an embodiment of the solar cell manufacturing method according to the present invention.

The solar cell manufacturing method of the present embodiment includes a step of forming the first semiconductor layer 21 and the second semiconductor layer 22 on the back surface of the semiconductor substrate 11 (step S01: semiconductor layer forming step), and the first semiconductor layer 21 and the second. A step of laminating the transparent electrode 30 on the back surface side of the semiconductor substrate 11 so as to cover the semiconductor layer 22 (step S02: transparent electrode laminating step) and a first base electrode 41 and a second by laminating the first conductive paste. A step of forming the base electrode 42 (step S03: base electrode forming step) and a step of forming the first insulating portion 61 and the second insulating portion 62 by laminating the insulating paste (step S04: insulating portion forming step). And the step of forming the first raised electrode 51 and the second raised electrode 52 by laminating the second conductive paste (step S05: raised electrode forming step), and the first base electrode 41, the first 2 A step of etching the transparent electrode 30 using the base electrode 42, the first insulating portion 61, the second insulating portion 62, the first raised electrode 51, and the second raised electrode 52 as masks (step S06: etching step). A step of firing the first base electrode 41, the second base electrode 42, the first insulating portion 61, the second insulating portion 62, the first raised electrode 51, and the second raised electrode 52 (step S07: firing step). A step of connecting the first wiring material 71 and the second wiring material 72 to the first raised electrode 51 and the second raised electrode 52 (step S08: wiring material connecting step) is provided.

In the semiconductor layer forming step of step S01, as shown in FIG. 5, the first semiconductor layer 21 and the second semiconductor layer 22 are formed so as to be alternately arranged in the second direction on the back surface of the semiconductor substrate 11. Specifically, the first semiconductor layer 21 and the second semiconductor layer 22 can be formed in order by forming a mask on the back surface of the semiconductor substrate 11 and laminating semiconductor materials by, for example, a film forming technique such as CVD. it can.

In the transparent electrode laminating step of step S02, as shown in FIG. 6, the entire back surface side of the semiconductor substrate 11 on which the first semiconductor layer 21 and the second semiconductor layer 22 are formed is covered with a film forming technique such as CVD or PVD. 1 The materials forming the transparent electrode 31 and the second transparent electrode 32 are laminated.

In the base electrode forming step of step S03, as shown in FIG. 7, the first base electrode 41 is formed in the region laminated on the first semiconductor layer 21 of the transparent electrode 30 by laminating the first conductive paste. At the same time, the second base electrode 42 is formed in the region laminated on the second semiconductor layer 22 of the transparent electrode 30. The first conductive paste can be selectively laminated by screen printing. Further, in the base electrode forming step, the solvent contained in the first conductive paste may be volatilized, and the formed first base electrode 41 and the second base electrode 42 may be dried so as not to be easily deformed. preferable. The drying conditions can be, for example, about 3 minutes at 150 ° C.

In the insulating portion forming step of step S04, as shown in FIG. 8, the first insulating portion 61 and the second insulating portion 62 are formed by laminating the insulating paste. The first insulating portions 61 are arranged across the transparent electrode 30 and the first base electrode 41 so as to be included in the first semiconductor layer 21 in a plan view, and are arranged in a matrix in the first direction and the second direction, respectively. It is formed. The second insulating portion 62 is arranged so as to be included in the second semiconductor layer 22 in a plan view so as to be included in the transparent electrode 30 and the second base electrode 42, respectively, and the second insulating portion 62 and the first insulating portion 61 in the first direction and the second direction. It is formed so as to be arranged in a matrix arranged alternately. The insulating paste can be selectively laminated by screen printing. Further, also in the insulating portion forming step, it is preferable to volatilize the solvent contained in the insulating paste and perform drying so that the formed first insulating portion 61 and the second insulating portion 62 are not easily deformed. The drying conditions can be, for example, about 3 minutes at 150 ° C.

In the step of forming the raised electrode in step S05, as shown in FIG. 9, by laminating the second conductive paste, the first raised electrode is formed in a region where the first insulating portion 61 of the first base electrode 41 is not laminated. The 51 is formed, and the second raised electrode 52 is formed in a region where the second insulating portion 62 of the second base electrode 42 is not laminated. The first raised electrode 51 and the second raised electrode 52 are arranged in a matrix arranged in the first direction and the second direction, respectively, and are formed so as to be alternately arranged in the first direction and the second direction. The second conductive paste can also be selectively laminated by screen printing. Further, also in the bulking electrode forming step, the solvent contained in the second conductive paste is volatilized, and the formed first raised electrode 51 and the second raised electrode 52 are dried so as not to be easily deformed. It is preferable to do so. The drying conditions can also be, for example, about 3 minutes at 150 ° C.

In the etching step of step S06, as shown in FIG. 10, the first base electrode 41, the second base electrode 42, the first insulating portion 61, the second insulating portion 62, the first raised electrode 51, and the second raised electrode The first semiconductor layer 21 is included in the first semiconductor layer 21 in a plan view by selectively removing the region of the transparent electrode 30 straddling the first semiconductor layer 21 and the second semiconductor layer 22 by etching with the 52 as a mask. The transparent electrode 31 and the second transparent electrode 32 included in the second semiconductor layer 22 are separated from each other in a plan view. As an etching solution capable of etching the transparent electrode 30 formed from ITO, for example, hydrochloric acid or the like can be used.

At this time, the widths of the first transparent electrode 31 and the second transparent electrode 32 separated by the side etch effect in the second direction are the first base electrode 41, the second base electrode 42, and the second base electrode 42, which are masked in a plan view. It is slightly smaller than the width of the envelope shape of the 1 insulating portion 61, the 2nd insulating portion 62, the 1st raised electrode 51, and the 2nd raised electrode 52 in the second direction. Therefore, the position shift occurs for some reason, and the first insulating portion 61 or the second insulating portion 62 causes the first base electrode 41, the second base electrode 42, the first raised electrode 51, and the second raised electrode 52. Even when the portion is in contact with the portion adjacent to the second direction, the transparent electrode 30 immediately below the contact portion can be removed to separate the first transparent electrode 31 and the second transparent electrode 32.

In the firing step of step S07, the first base electrode 41, the second base electrode 42, the first insulating portion 61, the second insulating portion 62, the first raised electrode 51, and the second raised electrode 52 are cured by heating. .. Further, in the firing step, the first base electrode 41, the second base electrode 42, the first insulating portion 61, the second insulating portion 62, the first raised electrode 51, and the second raised electrode 52 are formed by heating. The resin components of the conductive paste, the insulating paste, and the second conductive paste of No. 1 are exuded, and as shown in FIG. 11, the end faces of the first transparent electrode 31 and the second transparent electrode 32 on both sides in the second direction. The first coating portion 81 and the second coating portion 82 that cover a part or all of the above can be formed. The firing conditions can be, for example, 180 ° C. for about 60 minutes.

In the wiring material connecting step of step S08, between the first raised electrode 51 and the second raised electrode 52 arranged in the second direction by the first wiring material 71 and the second wiring material 72 extending in the second direction, respectively. Connecting. As a result, the solar cell 1 as shown in FIG. 2 can be obtained.

In the above solar cell manufacturing method, the transparent electrode 30 is formed on the front surface in the transparent electrode laminating step, and the first base electrode 41, the second base electrode 42, the first insulating portion 61, and the second insulating portion are formed in the transparent electrode selective removal step. Since etching is performed using 62, the first raised electrode 51 and the second raised electrode 52 as masks, it is not necessary to form a dedicated mask for forming the first transparent electrode 31 and the second transparent electrode 32. A highly efficient solar cell 1 can be manufactured at a relatively low cost.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and modifications can be made. For example, the solar cell according to the present invention has additional components such as an intrinsic semiconductor layer that insulates between each component, an antireflection film that suppresses light reflection, and a resin film that protects electrodes and the like, in addition to the above-mentioned components. May be provided. Further, in the solar cell according to the present invention, the covering portion may not be provided. That is, the first conductive paste forming the first base electrode and the second base electrode, the insulating paste forming the first insulating portion and the second insulating portion, and the first raised electrode and the second raised electrode are formed. As the second conductive paste, one in which the resin component does not easily exude during firing may be used.

In the solar cell manufacturing method according to the present invention, firing may be performed before the etching step. In this case, since the covering portion is not formed, it is preferable to use as the first conductive paste, the insulating paste and the second conductive paste, which are hard to exude the resin component at the time of firing. Further, in the solar cell manufacturing method according to the present invention, the order of the insulating portion forming step and the raised electrode forming step may be changed.

1 Solar cell 11 Semiconductor substrate 21 1st semiconductor layer 22 2nd semiconductor layer 31 1st transparent electrode 32 2nd transparent electrode 41 1st base electrode 42 2nd base electrode 51 1st raised electrode 52 2nd raised electrode 61 1 Insulation part 62 Second insulation part 71 First wiring material 72 Second wiring material 81 First coating part 82 Second coating part

Claims

A step of alternately forming a first semiconductor layer and a second semiconductor layer extending in the first direction on the back surface of the semiconductor substrate in the second direction intersecting the first direction, respectively.
A step of laminating a transparent electrode on the back surface side of the semiconductor substrate so as to cover the first semiconductor layer and the second semiconductor layer, and
By laminating the first conductive paste, the first base electrode extending in the first direction is formed in the region laminated with the first semiconductor layer of the transparent electrode, and the second semiconductor of the transparent electrode is formed. A step of forming a second base electrode extending in the first direction in each of the regions laminated in the layer, and a step of forming the second base electrode.
By laminating the insulating paste, they are arranged across the transparent electrode and the first base electrode so as to be encapsulated in the first semiconductor layer in a plan view, respectively, and are arranged in a matrix in the first direction and the second direction. A plurality of first insulating portions arranged in line with each other are formed, and are arranged across the transparent electrode and the second base electrode so as to be included in the second semiconductor layer in a plan view, respectively, in the first direction and the second. A step of forming a plurality of second insulating portions arranged in a matrix alternately arranged with the first insulating portion in the direction, and
By laminating the second conductive paste, the first raised electrode is formed in the region where the first insulating portion of the first base electrode is not laminated, and the second insulating portion of the second base electrode is formed. The step of forming the second raised electrode in the non-stacked region and
The transparent electrode is selectively selected by etching using the first base electrode, the second base electrode, the first insulating portion, the second insulating portion, the first raised electrode, and the second raised electrode as masks. The process of removing and
A step of connecting between the first raised electrodes and between the second raised electrodes by the first wiring material and the second wiring material extending in the second direction, respectively.
A solar cell manufacturing method.
A claim further comprising a step of selectively exuding the transparent electrode and then heating to exude the resin contained in the first base electrode, the second base electrode, and the first insulating portion and the second insulating portion. Item 2. The solar cell manufacturing method according to item 1.
The solar cell manufacturing method according to claim 1 or 2, wherein the first conductive paste, the insulating paste, and the second conductive paste are laminated by screen printing, respectively.
With a semiconductor substrate
A plurality of first semiconductor layers and a plurality of second semiconductor layers extending in the first direction and alternately provided in the second direction intersecting the first direction on the back surface of the semiconductor substrate.
A plurality of first transparent electrodes laminated on each of the first semiconductor layers so as to extend in the first direction, and a plurality of second transparent electrodes laminated on each of the second semiconductor layers so as to extend in the first direction. When,
A plurality of first base electrodes laminated so as to extend in the first direction on each of the first transparent electrodes, and a plurality of second base electrodes laminated so as to extend in the first direction on each of the second transparent electrodes. When,
A plurality of first raised electrodes arranged in a matrix at intervals in the first direction and the second direction so as to be laminated on a plurality of portions of each of the first base electrodes, and each of the above. A plurality of second raised electrodes arranged in a matrix in the first direction and the second direction at intervals alternately from the first raised electrode so as to be laminated on a plurality of portions of the second base electrode. With electrodes
The portion of each of the first base electrodes between the first raised electrodes is covered, and the first transparent electrode and the first base electrode are laminated so as to be included in the first semiconductor layer in a plan view. The second transparent electrode and the said A second insulating part laminated over the second base electrode and
A first wiring material arranged on the back surface side of the first raised electrode and the first insulating portion and electrically connecting between the first raised electrodes, and the second raised electrode and the second insulating. A second wiring material, which is arranged on the back surface side of the portion and electrically connects between the second raised electrodes,
With a solar cell.
The first insulating portion and the second insulating portion are separated from the first semiconductor layer and the second semiconductor layer.
The width of the first insulating portion in the second direction is larger than the width of the first transparent electrode in the second direction, and the width of the second insulating portion in the second direction is the width of the second transparent electrode. The solar cell according to claim 4, which is larger than the width in two directions.
The width in the second direction of the region where the first insulating portion of the first base electrode is laminated and the portion where the second insulating portion of the second base electrode is laminated is the width of the first base electrode. 1 The width of the region where the raised electrodes are laminated and the portion of the second base electrode on which the second raised electrode is laminated is smaller than the width in the second direction.
The width of the first insulating portion and the second insulating portion in the second direction is the region where the first raised electrode of the first base electrode is laminated and the second raised electrode of the second base electrode. The solar cell according to claim 4 or 5, wherein the width of the portion where is laminated is substantially equal to the width of the portion in the second direction.
The solar cell according to any one of claims 4 to 6, wherein the first transparent electrode and the side surface of the second transparent electrode are at least partially coated with a resin.