JP7539415B2 - Solar cell manufacturing method and solar cell - Google Patents

Description

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

A back-contact solar cell is known that includes a plurality of strip-shaped first and second semiconductor layers alternately formed on the back surface of a semiconductor substrate, a plurality of strip-shaped first and second base electrodes stacked on the first and second semiconductor layers, respectively, a plurality of first and second elevated electrodes stacked alternately on the first and second base electrodes, a first wiring material arranged to bridge between the plurality of first elevated electrodes, and a second wiring material arranged to bridge between the plurality of second elevated electrodes.

In such solar cells, in order to prevent short circuits between the first base electrode and the second wiring material, and between the second base electrode and the first wiring material, a configuration is also known in which insulating material is laminated in the area where the first base electrode intersects with the second wiring material and in the area where the second base electrode intersects with the first wiring material (see, for example, Patent Document 1).

JP 2011-3724 A

In the solar cell described above, the base electrode and the elevated electrode can be formed relatively easily by screen printing a material such as silver paste. Insulating material that prevents short circuits between the base electrode and the wiring material can also be disposed 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 silver paste is relatively expensive, forming a wide base electrode using silver paste causes the inconvenience of increasing the cost of the solar cell. Therefore, the objective of the present invention is to provide a solar cell manufacturing method that can manufacture highly efficient solar cells at low cost, and a solar cell that is inexpensive and highly efficient.

A solar cell manufacturing method according to one aspect of the present invention includes the steps of: forming a first semiconductor layer and a second semiconductor layer, each extending in a first direction, alternately on the back surface of a semiconductor substrate in a second direction intersecting the first direction; stacking 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; stacking a first conductive paste to form a first base electrode extending in the first direction in the region of the transparent electrode stacked on the first semiconductor layer, and a second base electrode extending in the first direction in the region of the transparent electrode stacked on the second semiconductor layer; stacking an insulating paste to form a plurality of first insulating parts arranged in a matrix in the first direction and the second direction, each of which is disposed across the transparent electrode and the first base electrode so as to be included in the first semiconductor layer in a plan view; the step of forming a plurality of second insulating portions arranged in a matrix and alternately arranged with the first insulating portions in the first direction and the second direction, the second insulating portions being disposed across the transparent electrode and the second base electrode so as to be included in the second semiconductor layer in a planar view; the step of forming a first elevated electrode in a region of the first base electrode where the first insulating portion is not laminated and forming a second elevated electrode in a region of the second base electrode where the second insulating portion is not laminated by stacking a second conductive paste; the step of selectively removing the transparent electrode by etching using the first base electrode, the second base electrode, the first insulating portion, the second insulating portion, the first elevated electrode, and the second elevated electrode as a mask; and the step of connecting the first elevated electrodes and the second elevated electrodes, respectively, by first wiring material and second wiring material extending in the second direction.

The solar cell manufacturing method according to the above aspect may further include a step of, after selectively removing the transparent electrode, causing the resin contained in the first base electrode and the second base electrode and the first insulating portion and the second insulating portion to seep out by heating.

In the solar cell manufacturing method relating to the above aspect, the lamination of the first conductive paste, the lamination of the insulating paste and the lamination of the second conductive paste may each be performed by screen printing.

A solar cell according to another aspect of the present invention includes a semiconductor substrate, a plurality of first semiconductor layers and a plurality of second semiconductor layers extending in a first direction on the rear surface of the semiconductor substrate and arranged alternately in a second direction intersecting the first direction, a plurality of first transparent electrodes stacked on each of the first semiconductor layers so as to extend in the first direction, a plurality of second transparent electrodes stacked on each of the second semiconductor layers so as to extend in the first direction, a plurality of first base electrodes stacked on each of the first transparent electrodes so as to extend in the first direction, a plurality of second base electrodes stacked on each of the second transparent electrodes so as to extend in the first direction, a plurality of first elevated electrodes arranged in a matrix at intervals in the first direction and the second direction so as to be stacked on a plurality of portions of each of the first base electrodes, and a plurality of portions of each of the second base electrodes. a first insulating portion covering a portion of each of the first base electrodes between the first elevated electrodes and laminated across the first transparent electrode and the first base electrode so as to be included in the first semiconductor layer in a planar view, and a second insulating portion covering a portion of each of the second base electrodes between the second elevated electrodes and laminated across the second transparent electrode and the second base electrode so as to be included in the second semiconductor layer in a planar view; a first wiring material arranged on a back side of the first elevated electrode and the first insulating portion, electrically connecting the first elevated electrodes, and a second wiring material arranged on a back side of the second elevated electrode and the second insulating portion, electrically connecting the second elevated electrodes.

In the solar cell relating to the above aspect, the first insulating portion and the second insulating portion are spaced apart from the first semiconductor layer and the second semiconductor layer, the width of the first insulating portion in the second direction is greater 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 greater than the width of the second transparent electrode in the second direction.

In the solar cell according to the above aspect, 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 may be smaller than the width in the second direction of the region where the first elevated electrode of the first base electrode is laminated and the portion where the second elevated electrode of the second base electrode is laminated, and the width in the second direction of the first insulating portion and the second insulating portion may be approximately equal to the width in the second direction of the region where the first elevated electrode of the first base electrode is laminated and the portion where the second elevated electrode of the second base electrode is laminated.

In the solar cell relating 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.

The present invention provides a solar cell manufacturing method capable of producing highly efficient solar cells at low cost, and a solar cell that is low cost and highly efficient.

FIG. 2 is a rear view showing the configuration of a solar cell according to one embodiment of the present invention. 2 is a cross-sectional view of the solar cell shown in FIG. 1 taken along line AA. 2 is a rear view showing the solar cell of FIG. 1 with some components removed. FIG. 1 is a flowchart showing the steps of a solar cell manufacturing method according to one embodiment of the present invention. 5 is a schematic cross-sectional view showing a step of the solar cell manufacturing method of FIG. 4. 5 in the solar cell manufacturing method of FIG. 4. FIG. 5 is a schematic cross-sectional view showing a step subsequent to that of FIG. 6 in the method of manufacturing the solar cell of FIG. 4. 8 is a schematic cross-sectional view showing a step subsequent to that of FIG. 7 in the method of manufacturing the solar cell of FIG. 4 . 8 in the solar cell manufacturing method of FIG. 4. FIG. 5 is a schematic cross-sectional view showing a step subsequent to that of FIG. 9 in the method of manufacturing the solar cell of FIG. 4 . 10 in the solar cell manufacturing method of FIG. 4. FIG.

Below, an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a schematic back view showing the configuration of a solar cell 1 according to one embodiment of the present invention. Figure 2 is a cross-sectional view of the solar cell 1 of Figure 1 taken along line A-A. Note that the hatching in Figure 1 is added to make it easier to distinguish between the various components, and does not mean a cross section. Also, for convenience, hatching and component symbols may be omitted, in which case reference should be made to other drawings. Also, the dimensions of the various components in the drawings have been adjusted for convenience so as to make them easy to see.

The solar cell 1 is a so-called heterojunction back-contact type solar cell. The solar cell 1 comprises a semiconductor substrate 11, a first semiconductor layer 21 and a second semiconductor layer 22 disposed on the back surface (the surface opposite to the light incidence surface) of the semiconductor substrate 11, a first transparent electrode 31 and a second transparent electrode 32 disposed on the back surface sides of the first semiconductor layer 21 and the second semiconductor layer 22, respectively, a first base electrode 41 and a second base electrode 42 disposed on the back surface sides of the first transparent electrode 31 and the second transparent electrode 32, respectively, and a plurality of transparent electrodes 41 and 42 disposed on each of the first base electrode 41 and the second base electrode 42. the first elevated electrode 51 and the second elevated electrode 52 being disposed on the first base electrode 41 and the second base electrode 42, a first insulating portion 61 and a second insulating portion 62 covering areas of the first base electrode 41 and the second base electrode 42 where the first elevated electrode 51 and the second elevated electrode 52 are not disposed, a first wiring member 71 and a second wiring member 72 connecting the first elevated electrodes 51 and the second elevated electrodes 52, respectively, and a first covering portion 81 and a second covering portion 82 at least partially covering the side surfaces of the first transparent electrode 31 and the second transparent electrode 32.

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. An example of an n-type dopant is phosphorus (P). The semiconductor substrate 11 functions as a photoelectric conversion substrate that absorbs incident light from the light receiving surface side and generates photocarriers (electrons and holes). By using crystalline silicon as the material for the semiconductor substrate 11, the dark current is relatively small, and a relatively high output (stable output regardless of illuminance) can be obtained even when the intensity of the incident light is low.

The first semiconductor layer 21 and the second semiconductor layer 22 have different conductivity types. For 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 the desired conductivity type. An example of the p-type dopant is boron (B), and an example of the n-type dopant is phosphorus (P) as described above.

The first semiconductor layer 21 and the second semiconductor layer 22 are each formed in a strip shape extending in a first direction. In the solar cell 1, a plurality of first semiconductor layers 21 and a plurality of second semiconductor layers 22 are alternately provided in a 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. The first transparent electrode 31 and the second transparent electrode 32 also function as intermediate layers that prevent a decrease in adhesion and an increase in electrical resistance at the interface caused by differences in materials between the first semiconductor layer 21 and the second semiconductor layer 22 and the first base electrode 41 and the second base electrode 42.

The first transparent electrode 31 and the second transparent electrode 32 are stacked in the first direction over substantially the entire length of the first semiconductor layer 21 and the second semiconductor layer 22 with 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 contact each other. The width of the first transparent electrode 31 and the second transparent electrode 32 in the second direction changes in response to the first base electrode 41 and the second base electrode 42 and the first insulating portion 61 and the second insulating portion 62 described later.

The first transparent electrode 31 and the second transparent electrode 32 can be formed from the same material. Examples of materials for forming the first transparent electrode 31 and the second transparent electrode 32 include ITO (Indium Tin Oxide) and zinc oxide (ZnO). In addition, the first transparent electrode 31 and the second transparent electrode 32 are stacked over a larger area than the first base electrode 41 and the second base electrode 42 described below, thereby improving the current collection ability of the first base electrode 41 and the second base electrode 42.

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 power via the first transparent electrode 31 and the second transparent electrode 32.

3 shows the solar cell 1 with the first elevated electrode 51, the second elevated electrode 52, the first wiring material 71, and the second wiring material 72 removed. As shown in the figure, the width in the second direction of the portion where the first elevated electrode 51 and the second elevated electrode 52 of the first base electrode 41 and the second base electrode 42 are stacked is greater than the width in the second direction of the portion therebetween, that is, the portion where the first insulating portion 61 and the second insulating portion 62 of the first base electrode 41 and the second base electrode 42 are stacked.

More specifically, the width in the second direction of the first base electrode 41 and the second base electrode 42 in the portion where the first elevated electrode 51 and the second elevated electrode 52 are stacked is set so as to ensure the necessary height of the first elevated electrode 51 and the second elevated electrode 52 and a sufficient connection area between the first wiring material 71 and the second wiring material 72. In addition, the width in the second direction of the first base electrode 41 and the second base electrode 42 in the region where the first elevated electrode 51 and the second elevated electrode 52 are stacked may be slightly larger than the width in the second direction of the first transparent electrode 31 or the second transparent electrode 32. In other words, the first base electrode 41 and the second base electrode 42 may have an area at the end in the second direction that faces the first semiconductor layer 21 and the second semiconductor layer 22 with a gap therebetween without the first transparent electrode 31 and the second transparent electrode 32 being interposed therebetween.

In addition, the width in the second direction of the region between the first elevated electrode 51 or the second elevated electrode 52 of the first base electrode 41 and the second base electrode 42, that is, the portion where the first insulating portion 61 and the second insulating portion 62 of the first base electrode 41 and the second base electrode 42 are laminated, is preferably set to the minimum size necessary to ensure conductivity. Taking into account the positional deviation of each component, it is more preferable that the width of the first base electrode 41 and the second base electrode 42 is reduced only in the region covered by the first insulating portion 61 and the second insulating portion 62 except for both ends in the first direction.

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. A specific example of the conductive paste is a silver paste. By using the conductive paste, the first base electrode 41 and the second base electrode 42 can be formed relatively inexpensively with a sufficient thickness to reduce electrical resistance.

The first elevated electrodes 51 are arranged in a matrix with gaps in the first and second directions so as to be stacked on multiple portions of each of the first base electrodes 41, and the second elevated electrodes 52 are arranged in a matrix with gaps in between the first elevated electrodes 51 in the first and second directions so as to be stacked on multiple portions of each of the second base electrodes 42. The first elevated electrode 51 is interposed between the first base electrode 41 and the first wiring member 71 to separate the first wiring member 71 from the second base electrode 42. The second elevated electrode 52 is interposed between the second base electrode 42 and the second wiring member 72 to separate the second wiring member 72 from the first base electrode 41.

The first elevated electrode 51 and the second elevated electrode 52 can be formed from a conductive paste such as silver paste, and are preferably formed from the same type of material as the first base electrode 41 and the second base electrode 42 in order to improve adhesion with the first base electrode 41 and the second base electrode 42.

The height of the first and second bulky electrodes 51 and 52 is preferably sufficiently greater than the height of the first and second insulating parts 61 and 62 so as to ensure reliable contact with the first and second wiring members 71 and 72. The width of the first and second bulky electrodes 51 and 52 in the second direction is preferably approximately equal to the width of the laminated region of the first and second base electrodes 41 and 42 in order to efficiently increase the height. The length of the first and second bulky electrodes 51 and 52 in the first direction is preferably smaller than the distance in the first direction so that the first and second bulky electrodes 51 and 52 do not overlap when viewed from the second direction in order to prevent a short circuit between the first and second wiring members 72 and between the second and first wiring members 71.

The first insulating portion 61 covers the portion between the first elevated electrodes 51 of each of the first base electrodes 41, and is laminated across the first transparent electrode 31 and the first base electrode 41 so as to be included in the first semiconductor layer 21 in a planar view. The second insulating portion 62 covers the portion between the second elevated electrodes 52 of each of the second base electrodes 42, and is laminated across the second transparent electrode 32 and the second base electrode 42 so as to be included in the second semiconductor layer 22 in a planar view. The first insulating portion 61 and the second insulating portion 62 may be laminated on the ends of the first elevated electrode 51 and the second elevated electrode 52 in the first direction. The first insulating portion 61 and the second insulating portion 62 ensure insulation between the first wiring member 71 and the second base electrode 42 and insulation between the second wiring member 72 and the first base electrode 41. Furthermore, 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 which have a small cross-sectional area to prevent contact with moisture, etc., thereby preventing the portions of the first base electrode 41 and the second base electrode 42 which have a small cross-sectional area from corroding and causing a significant loss of conductivity, and preventing the first base electrode 41 and the second base electrode 42 from peeling off from the first transparent electrode 31 and the second transparent electrode 32.

It is preferable that the width in the second direction of the first insulating portion 61 and the second insulating portion 62 is approximately equal to the width in the second direction of the portion where the first elevated electrode 51 and the second elevated electrode 52 of the first base electrode 41 and the second base electrode 42 are laminated. This allows the width in the second direction of the first transparent electrode 31 and the second transparent electrode 32 to be approximately constant, so that the width in the second direction of the first transparent electrode 31 and the second transparent electrode 32 can be increased to further reduce the current collection resistance. In addition, it is preferable that the length in the first direction of the first insulating portion 61 and the second insulating portion 62 is greater than the length in the first direction of the first elevated electrode 51 and the second elevated electrode 52 in order to prevent a short circuit between the first elevated electrode 51 and the second wiring member 72 and a short circuit between the second elevated electrode 52 and the first wiring member 71.

The first insulating portion 61 and the second insulating portion 62 can be formed from a paste-like material having insulating properties. The material for forming the first insulating portion 61 and the second insulating portion 62 can be, for example, a thermosetting resin composition mainly composed of an epoxy resin or the like.

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

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

The first covering portion 81 and the second covering portion 82 cover both end faces in the second direction of the first transparent electrode 31 and the second transparent electrode 32. The first covering portion 81 and the second covering 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 covering portion 81 and the second covering portion 82, even if moisture penetrates into a solar cell module formed using the solar cell 1, the first transparent electrode 31 and the second transparent electrode 32 can be protected and a decrease in performance of the solar cell 1 can be suppressed.

As described above, the solar cell 1 can be manufactured relatively inexpensively because the first base electrode 41, the second base electrode 42, the first elevated electrode 51, and the second elevated electrode 52 for current collection can be formed by printing and baking a paste-like material without using a film formation technique that requires vacuum equipment. Furthermore, the solar cell 1 is provided with the first transparent electrode 31 and the second transparent electrode 32 that extract power from the first semiconductor layer 21 and the second semiconductor layer 22, so that the width of the portion between the first elevated electrode 51 and the second elevated electrode 52 of the first base electrode 41 and the second base electrode 42 can be reduced. This reduces the amount of relatively expensive conductive paste used, so the solar cell 1 can be manufactured relatively inexpensively while being highly efficient.

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 Figure 4. The solar cell manufacturing method in Figure 4 is one embodiment of the solar cell manufacturing method according to the present invention.

The solar cell manufacturing method of this embodiment includes a step of forming a first semiconductor layer 21 and a second semiconductor layer 22 on the back surface of the semiconductor substrate 11 (step S01: semiconductor layer formation step), a step of laminating a transparent electrode 30 on the back surface side of the semiconductor substrate 11 so as to cover the first semiconductor layer 21 and the second semiconductor layer 22 (step S02: transparent electrode lamination step), a step of forming a first base electrode 41 and a second base electrode 42 by laminating a first conductive paste (step S03: base electrode formation step), a step of forming a first insulating portion 61 and a second insulating portion 62 by laminating an insulating paste (step S04: insulating portion formation step), and a step of forming a first insulating portion 61 and a second insulating portion 62 by laminating a second conductive paste (step S05: insulating portion formation step). The method includes a step of forming the first elevated electrode 51 and the second elevated electrode 52 (step S05: elevated electrode forming step), a step of etching the transparent electrode 30 using the first base electrode 41, the second base electrode 42, the first insulating portion 61, the second insulating portion 62, the first elevated electrode 51, and the second elevated electrode 52 as a mask (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 elevated electrode 51, and the second elevated electrode 52 (step S07: firing step), and a step of connecting the first wiring member 71 and the second wiring member 72 to the first elevated electrode 51 and the second elevated electrode 52 (step S08: wiring member connecting step).

5, in the semiconductor layer formation process of step S01, the first semiconductor layer 21 and the second semiconductor layer 22 are formed on the back surface of the semiconductor substrate 11 so as to be alternately arranged in the second direction. 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 stacking semiconductor materials by a film formation technique such as CVD.

In the transparent electrode lamination process of step S02, as shown in FIG. 6, materials for forming the first transparent electrode 31 and the second transparent electrode 32 are laminated on 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, for example, by a film formation technique such as CVD or PVD.

In the base electrode formation process of step S03, as shown in FIG. 7, a first conductive paste is laminated to form a first base electrode 41 in the area laminated on the first semiconductor layer 21 of the transparent electrode 30, and a second base electrode 42 is formed in the area laminated on the second semiconductor layer 22 of the transparent electrode 30. The first conductive paste can be selectively laminated by screen printing. In addition, in the base electrode formation process, it is preferable to volatilize the solvent contained in the first conductive paste and dry the first base electrode 41 and the second base electrode 42 so that they do not easily deform. The drying conditions can be, for example, about 3 minutes at 150°C.

In the insulating part forming process of step S04, as shown in FIG. 8, the first insulating part 61 and the second insulating part 62 are formed by stacking insulating paste. The first insulating part 61 is 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 is formed so as to be arranged in a matrix in the first direction and the second direction. The second insulating part 62 is arranged across the transparent electrode 30 and the second base electrode 42 so as to be included in the second semiconductor layer 22 in a plan view, and is formed so as to be arranged in a matrix in which the first insulating part 61 and the second insulating part 62 are alternately arranged in the first direction and the second direction. The insulating paste can be selectively stacked by screen printing. Also, in the insulating part forming process, it is preferable to volatilize the solvent contained in the insulating paste and dry the formed first insulating part 61 and second insulating part 62 so that they do not easily deform. The drying conditions can be, for example, about 3 minutes at 150 ° C.

In the elevated electrode formation process of step S05, as shown in FIG. 9, the second conductive paste is laminated to form the first elevated electrode 51 in the area where the first insulating portion 61 of the first base electrode 41 is not laminated, and the second elevated electrode 52 is formed in the area where the second insulating portion 62 of the second base electrode 42 is not laminated. The first elevated electrode 51 and the second elevated electrode 52 are arranged in a matrix 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. In addition, in the elevated electrode formation process, it is preferable to volatilize the solvent contained in the second conductive paste and dry the formed first elevated electrode 51 and second elevated electrode 52 so that they do not easily deform. The drying conditions can also be, for example, about 3 minutes at 150 ° C.

10, in the etching process of step S06, the first base electrode 41, the second base electrode 42, the first insulating portion 61, the second insulating portion 62, the first elevated electrode 51, and the second elevated electrode 52 are used as a mask to selectively remove the area of the transparent electrode 30 that spans the first semiconductor layer 21 and the second semiconductor layer 22, thereby separating the first transparent electrode 31 that is included in the first semiconductor layer 21 in a planar view from the second transparent electrode 32 that is included in the second semiconductor layer 22 in a planar view. For example, hydrochloric acid can be used as an etching solution that can etch the transparent electrode 30 made of ITO.

At this time, due to the side etch effect, the width in the second direction of the separated first transparent electrode 31 and second transparent electrode 32 becomes slightly smaller than the width in the second direction of the envelope shape of the first base electrode 41, the second base electrode 42, the first insulating portion 61, the second insulating portion 62, the first elevated electrode 51, and the second elevated electrode 52 that are masked in a plan view. Therefore, even if a position shift occurs for some reason and the first insulating portion 61 or the second insulating portion 62 contacts the adjacent portion in the second direction of the first base electrode 41, the second base electrode 42, the first elevated electrode 51, and the second elevated electrode 52, the transparent electrode 30 directly below the contact portion can be removed to separate the first transparent electrode 31 and the second transparent electrode 32.

In the firing process 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 bulk electrode 51, and the second bulk electrode 52 are hardened by heating. In addition, in the firing process, the resin components of the first conductive paste, the insulating paste, and the second conductive paste that form the first base electrode 41, the second base electrode 42, the first insulating portion 61, the second insulating portion 62, the first bulk electrode 51, and the second bulk electrode 52 are exuded by heating, and as shown in FIG. 11, the first covering portion 81 and the second covering portion 82 that cover part or all of the end faces on both sides in the second direction of the first transparent electrode 31 and the second transparent electrode 32 can be formed. The firing conditions can be, for example, 180° C. for about 60 minutes.

In the wiring member connection process of step S08, the first wiring member 71 and the second wiring member 72 extending in the second direction connect the first elevated electrodes 51 and the second elevated electrodes 52 arranged in the second direction, respectively. This makes it possible to obtain the solar cell 1 as shown in FIG. 2.

In the above solar cell manufacturing method, a transparent electrode 30 is formed on the front surface in the transparent electrode lamination process, and etching is performed using the first base electrode 41, the second base electrode 42, the first insulating portion 61, the second insulating portion 62, the first elevated electrode 51 and the second elevated electrode 52 as masks in the transparent electrode selective removal process. Therefore, there is no need to form a dedicated mask for forming the first transparent electrode 31 and the second transparent electrode 32, and a highly efficient solar cell 1 can be manufactured at a relatively low cost.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and various modifications and variations are possible. For example, the solar cell according to the present invention may include, in addition to the above-mentioned components, further components such as an intrinsic semiconductor layer that insulates each component, an anti-reflection film that suppresses reflection of light, and a resin film that protects the electrodes, etc. In addition, the solar cell according to the present invention may not have a covering portion. In other words, the first conductive paste that forms the first base electrode and the second base electrode, the insulating paste that forms the first insulating portion and the second insulating portion, and the second conductive paste that forms the first elevated electrode and the second elevated electrode may be ones that are less likely to exude resin components during firing.

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 the first conductive paste, insulating paste, and second conductive paste from which the resin components are unlikely to seep out during firing. Also, in the solar cell manufacturing method according to the present invention, the order of the insulating portion forming step and the elevated electrode forming step may be reversed.

REFERENCE SIGNS LIST 1 solar cell 11 semiconductor substrate 21 first semiconductor layer 22 second semiconductor layer 31 first transparent electrode 32 second transparent electrode 41 first base electrode 42 second base electrode 51 first elevated electrode 52 second elevated electrode 61 first insulating portion 62 second insulating portion 71 first wiring member 72 second wiring member 81 first covering portion 82 second covering portion

Claims (7)

forming, on a rear surface of a semiconductor substrate, first semiconductor layers and second semiconductor layers each extending in a first direction, alternately in a second direction intersecting the first direction;
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;
forming a first base electrode extending in the first direction in a region of the transparent electrode laminated on the first semiconductor layer by laminating a first conductive paste, and forming a second base electrode extending in the first direction in a region of the transparent electrode laminated on the second semiconductor layer;
forming a plurality of first insulating portions arranged in a matrix in the first direction and the second direction, the first insulating portions being disposed across the transparent electrode and the first base electrode so as to be included in the first semiconductor layer in a planar view, and a plurality of second insulating portions arranged in a matrix in the first direction and the second direction, the second insulating portions being disposed across the transparent electrode and the second base electrode so as to be included in the second semiconductor layer in a planar view, and the second insulating portions being arranged alternately with the first insulating portions in the first direction and the second direction;
forming a first elevated electrode in a region of the first base electrode where the first insulating portion is not laminated, and forming a second elevated electrode in a region of the second base electrode where the second insulating portion is not laminated, by laminating a second conductive paste;
selectively removing the transparent electrode by etching using the first base electrode, the second base electrode, the first insulating portion, the second insulating portion, the first elevated electrode, and the second elevated electrode as a mask;
connecting the first elevated electrodes and the second elevated electrodes by first wiring members and second wiring members extending in the second direction, respectively;
A solar cell manufacturing method comprising: The solar cell manufacturing method according to claim 1, further comprising a step of exuding the resin contained in the first base electrode, the second base electrode, and the first insulating portion and the second insulating portion by heating after selectively removing the transparent electrode. The solar cell manufacturing method according to claim 1 or 2, wherein the lamination of the first conductive paste, the lamination of the insulating paste, and the lamination of the second conductive paste are each performed by screen printing. A semiconductor substrate;
a plurality of first semiconductor layers and a plurality of second semiconductor layers each extending in a first direction and alternately provided in a second direction intersecting the first direction on a rear 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;
a plurality of first base electrodes stacked on each of the first transparent electrodes to extend in the first direction, and a plurality of second base electrodes stacked on each of the second transparent electrodes to extend in the first direction;
a plurality of first elevated electrodes arranged in a matrix at intervals in the first direction and the second direction so as to be stacked on a plurality of portions of each of the first base electrodes; and a plurality of second elevated electrodes arranged in a matrix at intervals alternately with the first elevated electrodes in the first direction and the second direction so as to be stacked on a plurality of portions of each of the second base electrodes;
a first insulating portion that covers a portion of each of the first base electrodes between the first elevated electrodes and is laminated across the first transparent electrode and the first base electrode so as to be included in the first semiconductor layer in a plan view, and a second insulating portion that covers a portion of each of the second base electrodes between the second elevated electrodes and is laminated across the second transparent electrode and the second base electrode so as to be included in the second semiconductor layer in a plan view;
a first wiring member disposed on a rear surface side of the first elevated electrode and the first insulating portion, electrically connecting the first elevated electrodes, and a second wiring member disposed on a rear surface side of the second elevated electrode and the second insulating portion, electrically connecting the second elevated electrodes;
A solar cell comprising: the first insulating portion and the second insulating portion are spaced apart from the first semiconductor layer and the second semiconductor layer,
The solar cell of claim 4 , wherein the width in the second direction of the first insulating portion is greater than the width in the second direction of the first transparent electrode, and the width in the second direction of the second insulating portion is greater than the width in the second direction of the second transparent electrode. a width in the second direction of a region of the first base electrode where the first insulating portion is laminated and a portion of the second base electrode where the second insulating portion is laminated is smaller than a width in the second direction of a region of the first base electrode where the first elevated electrode is laminated and a portion of the second base electrode where the second elevated electrode is laminated,
6. The solar cell according to claim 4 or 5, wherein the width in the second direction of the first insulating portion and the second insulating portion is approximately equal to the width in the second direction of a region of the first base electrode where the first elevated electrode is stacked and a portion of the second base electrode where the second elevated electrode is stacked. A solar cell according to any one of claims 4 to 6, wherein the side surfaces of the first transparent electrode and the second transparent electrode are at least partially covered with a resin.

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