JP2018074125A - Solar battery cell, solar battery module, and method for manufacturing solar battery cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar battery cell arranged so that even if a stress is applied to the solar battery cell, the decrease in output can be suppressed by controlling a position where the stress is concentrated.SOLUTION: A solar battery cell 10 comprises: a silicon substrate 10d having crystallinity; a plurality of finger electrodes 70 provided on a first principal face of the silicon substrate 10d and serving to collect light-reception charges generated in a light-receiving region on the silicon substrate 10d; n wiring lines 80 (n is an integer of 2 or larger) provided to be orthogonal to the plurality of finger electrodes 70 and serving to collect light-reception charges generated in the light-receiving region on the silicon substrate 10d; and one or more concave parts 90 formed on at least one of the first principal face and a second principal face opposed to the first principal face. Each of the one or more concave parts 90 is formed in a region 91 between a straight line S1 extending along one wiring line 80a of the two wiring lines 80 located at outermost positions, and a straight line S2 extending along the other wiring line 80b in plan view for the solar battery cell 10.SELECTED DRAWING: Figure 4A

Description

  The present invention relates to a solar battery cell, a solar battery module including the solar battery cell, and a method for manufacturing the solar battery cell.

  2. Description of the Related Art Conventionally, solar cells and solar cell modules using solar cells have been developed as photoelectric conversion devices that convert light energy into electrical energy. Solar cells and solar cell modules using solar cells can convert inexhaustible sunlight directly into electricity, and are environmentally friendly and less clean than fossil fuel power generation. Expected.

  For example, Patent Document 1 discloses a solar battery cell and a solar battery module that improve photoelectric conversion efficiency.

Japanese Patent Laying-Open No. 2015-188117

  However, in the solar cell of Patent Document 1, when stress is applied to the solar cell, a position where the stress is concentrated (stress concentration position) is not considered. That is, in the solar cell of Patent Document 1, the stress concentration position cannot be controlled. Therefore, depending on the stress concentration position, a region that is electrically divided in the solar battery cell is generated, thereby reducing the output of the solar battery cell. Moreover, in a solar cell module provided with a plurality of solar cells, the output of the solar cell module is reduced due to a decrease in the output of the solar cell.

  Therefore, an object of the present invention is to provide a solar battery cell or the like that can suppress a decrease in output by controlling the stress concentration position even when stress is applied to the solar battery cell.

  In order to achieve the above object, one aspect of a solar cell according to the present invention is provided in a silicon substrate having crystallinity and a first main surface of the silicon substrate, and is generated in a light receiving region on the silicon substrate. A plurality of finger electrodes for collecting received light charges and n (n is an integer of 2 or more) provided to be orthogonal to the finger electrodes and for collecting received light charges generated in the light receiving region on the silicon substrate Wiring and one or more recesses formed in at least one of the first main surface and the second main surface facing away from the first main surface, each of the one or more recesses being a solar battery cell In plan view, the outermost two wirings are formed in a region sandwiched between a straight line obtained by extending one wiring and a straight line obtained by extending the other wiring.

  Moreover, one aspect of the solar cell module according to the present invention is a solar cell module including a plurality of solar cells and a wiring member that electrically connects the adjacent solar cells, and the plurality of solar cells. At least one of the cells is a solar cell as described above.

  Moreover, the one aspect | mode of the manufacturing method of the photovoltaic cell which concerns on this invention is a manufacturing method of the photovoltaic cell as described above, Comprising: The process of forming the said recessed part by laser processing is included.

  According to the solar cell etc. which concern on this invention, even when stress is added to the photovoltaic cell, the fall of an output can be suppressed.

3 is a schematic plan view of the solar cell module according to Embodiment 1. FIG. It is sectional drawing of the solar cell module which concerns on Embodiment 1 in the II-II line | wire of FIG. 3 is a cross-sectional view showing an example of a solar battery cell according to Embodiment 1. FIG. 3 is a plan view showing an example of a recess formed in the solar battery cell according to Embodiment 1. FIG. It is sectional drawing of the photovoltaic cell which concerns on Embodiment 1 in the IVB-IVB line | wire of FIG. 4A. It is a figure which shows the example which forms a recessed part by laser processing. 6 is a plan view showing an example of a recess formed in a solar battery cell according to Embodiment 2. FIG. 10 is a plan view showing an example of a recess and a groove formed in a solar battery cell according to Embodiment 3. FIG.

  Below, the photovoltaic cell which concerns on embodiment of this invention, and a photovoltaic module provided with the said photovoltaic cell are demonstrated in detail using drawing. Each of the embodiments described below shows a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement of components, connection modes, processes, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.

  Each figure is a schematic diagram and is not necessarily shown strictly. Moreover, in each figure, the same code | symbol is attached | subjected to the substantially same structure, The overlapping description may be abbreviate | omitted or simplified.

  In the present specification, the description of “substantially **” is intended to include what is substantially recognized as **. For example, when “substantially parallel” is described as an example, It is intended to include things that are recognized as parallel to.

  Moreover, in each figure, a Z-axis direction is a direction perpendicular | vertical to the main surface of a solar cell module and the main surface of a photovoltaic cell. The X-axis direction and the Y-axis direction are orthogonal to each other, and both are directions orthogonal to the Z-axis direction. For example, in the following embodiments, “plan view” means viewing from the Z-axis direction.

(Embodiment 1)
The first embodiment will be described below with reference to FIGS.

[1. Schematic configuration of solar cell module]
First, an example of a schematic configuration of the solar cell module according to the present embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a schematic plan view of a solar cell module 1 according to the present embodiment. FIG. 2 is a cross-sectional view of solar cell module 1 according to the present embodiment taken along line II-II in FIG.

  As shown in FIGS. 1 and 2, the solar cell module 1 includes a plurality of solar cells 10, a tab wiring 20, a surface protection member 30, a back surface protection member 40, a filling member 50, and a frame 60. Prepare. The solar cell module 1 has a structure in which a plurality of solar cells 10 are sealed with a filling member 50 between a front surface protection member 30 and a back surface protection member 40.

  As shown in FIG. 1, the planar view shape of the solar cell module 1 is a substantially rectangular shape, for example.

  Hereinafter, each component of the solar cell module 1 will be described in more detail with reference to FIGS. 1, 2, and FIGS. 3, 4 </ b> A, and 4 </ b> B.

[1-1. Solar cell]
The solar cell 10 is a photoelectric conversion element (photovoltaic element) that converts light such as sunlight into electric power. As shown in FIG. 1, a plurality of solar cells 10 are arranged in a matrix (matrix shape) on the same plane.

  The plurality of solar cells 10 arranged in a straight line form a string (cell string) by connecting two adjacent solar cells 10 by tab wiring 20. The plurality of solar cells 10 in one string 10S are electrically connected by the tab wiring 20 and connected in series.

  Each string 10S is connected to other wiring (not shown) via the tab wiring 20. Thus, a plurality of strings 10S are connected in series or in parallel to form a cell array.

  As shown in FIG. 1, the plurality of solar cells 10 are arranged with gaps between the solar cells 10 adjacent in the row direction and the column direction. For example, a light reflecting member (not shown) may be disposed in the gap. Thereby, the light incident on the gap region between the solar battery cells 10 is reflected on the surface of the light reflecting member. This reflected light is reflected again at the interface between the surface protection member 30 and the external space of the solar cell module 1 and redistributed onto the solar cells 10. Therefore, the photoelectric conversion efficiency of the entire solar cell module 1 can be improved.

  In this Embodiment, the planar view shape of the photovoltaic cell 10 is substantially rectangular shape. For example, the solar battery cell 10 has a shape in which a 125 mm square square is missing. For example, the thickness of the silicon substrate 10d is 150 μm or less.

  FIG. 3 is a cross-sectional view showing an example of the solar battery cell 10 according to the present embodiment. Moreover, FIG. 4A is a top view which shows an example of the recessed part 90 currently formed in the photovoltaic cell 10 which concerns on this Embodiment. 3 is a cross-sectional view taken along line III-III in FIG. 4A.

  As shown in FIG. 3, the solar cell 10 has a semiconductor pn junction as a basic structure. As an example, one of an n-type single crystal silicon substrate 10d and an n-type single crystal silicon substrate 10d, which is an n-type semiconductor substrate. P-type amorphous silicon layer 10b and p-side electrode 10a sequentially formed on the main surface side of the n-type, and n-type amorphous silicon sequentially formed on the other main surface side of the n-type single crystal silicon substrate 10d. The layer 10e and the n-side electrode 10f are configured. The p-side electrode 10a and the n-side electrode 10f are transparent electrodes such as ITO (Indium Tin Oxide).

  Further, i is a passivation layer between the n-type single crystal silicon substrate 10d and the p-type amorphous silicon layer 10b and between the n-type single crystal silicon substrate 10d and the n-type amorphous silicon layer 10e. A type amorphous silicon layer 10c is provided. Thereby, it can suppress that the produced | generated carrier recombines. Therefore, the photoelectric conversion efficiency of the solar cell module 1 can be improved. Note that the passivation layer is not limited to the i-type amorphous silicon layer 10c, and may be a silicon oxide layer, a silicon nitride layer, or the like, or may not be provided.

  The crystalline silicon substrate constituting the solar cell 10 is not limited to a single crystal silicon substrate (n-type single crystal silicon substrate or p-type single crystal silicon substrate), but may be a polycrystalline silicon substrate. In the following description, the case where the crystalline silicon substrate is an n-type single crystal silicon substrate (hereinafter referred to as a silicon substrate 10d) will be described.

  Although the heterojunction solar cell has been described above, the solar cell 10 is not limited to the heterojunction type. For example, the solar cell 10 may be a crystalline silicon type solar cell such as a single crystal silicon type or a polycrystalline silicon type.

  In this Embodiment, although the photovoltaic cell 10 is arrange | positioned so that the p side electrode 10a may become the main light-receiving surface side of the solar cell module 1, it is not limited to this. For example, the n-side electrode 10f may be disposed on the main light receiving surface side of the solar cell module 1. Moreover, when the solar cell module 1 is a single-sided light reception system, the electrode located in the back surface side does not need to be transparent, For example, the metal electrode which has reflectivity may be sufficient.

  In each solar cell 10, the surface is a surface on the surface protection member 30 side, and the back surface is a surface on the back surface protection member 40 side. As shown in FIG. 2, the front surface collecting electrode 11 and the back surface collecting electrode 12 are formed in the solar battery cell 10. The surface collection electrode 11 is electrically connected to the surface side electrode (for example, p side electrode 10a) of the photovoltaic cell 10. The back surface collecting electrode 12 is electrically connected to the back surface side electrode (for example, n side electrode 10f) of the photovoltaic cell 10.

  Each of the front surface collecting electrode 11 and the back surface collecting electrode 12 is connected to, for example, a plurality of finger electrodes 70 formed linearly so as to be orthogonal to the extending direction of the tab wiring 20, and these finger electrodes 70. A plurality of bus bar electrodes 80 are formed in a straight line along the direction orthogonal to the finger electrode 70 (the extending direction of the tab wiring 20). For example, the number of bus bar electrodes 80 is the same as that of the tab wiring 20, and is three in the present embodiment. The number of bus bar electrodes 80 is not limited to three and may be two or more. Further, the front collector electrode 11 and the rear collector electrode 12 have the same shape as each other, but are not limited thereto. The bus bar electrode 80 is an example of wiring.

  As for the photovoltaic cell 10 comprised in this way, both the front surface and a back surface become a light-receiving surface. When light enters the solar battery cell 10, carriers are generated in the photoelectric conversion part of the solar battery cell 10. The generated carriers are collected by the front surface collecting electrode 11 and the back surface collecting electrode 12 and flow into the tab wiring 20. As described above, by providing the front collector electrode 11 and the rear collector electrode 12, carriers generated in the solar battery cell 10 can be efficiently taken out to an external circuit.

  Note that fine irregularities called a texture structure in which a plurality of pyramids are two-dimensionally arranged may be formed on the surface of the silicon substrate 10d. In the solar battery cell 10 whose both surfaces are light receiving surfaces, a texture structure may be formed on the front surface and the back surface of the silicon substrate 10d. Thereby, it can reduce that the reflected light reflected on the surface or the back surface of the photovoltaic cell 10 is emitted to the outside of the photovoltaic module 1 including the photovoltaic cell 10. That is, since the incident light into the solar battery cell 10 increases, the power generation efficiency of the solar battery cell 10 is improved. For example, the texture structure is formed by anisotropically etching the surface of the silicon substrate 10d. The depth of the texture structure (the depth defined by the top and the valley) is, for example, 1 μm or more and 10 μm or less.

[1-2. Tab wiring (interconnector)]
As shown in FIG.1 and FIG.2, the tab wiring 20 (interconnector) electrically connects two adjacent photovoltaic cells 10 in the string 10S. As shown in FIG. 1, in the present embodiment, two adjacent solar cells 10 are connected by three tab wirings 20 arranged substantially in parallel with each other. As shown in FIG. 2, for each tab wiring 20, one end of the tab wiring 20 is arranged on the surface of one of the two adjacent solar battery cells 10, The end portion is disposed on the back surface of the other solar battery cell 10 of the two adjacent solar battery cells 10. Each tab wiring 20 electrically connects the front surface collecting electrode 11 of one solar cell 10 and the back surface collecting electrode 12 of the other solar cell 10 in two adjacent solar cells 10. For example, the tab wiring 20 and the front surface collecting electrode 11 of the solar battery cell 10 and the bus bar electrode 80 of the back surface collecting electrode 12 are joined by a conductive adhesive such as a solder material or a resin adhesive. When the tab wiring 20 and the front surface collecting electrode 11 of the solar battery cell 10 and the bus bar electrode 80 of the back surface collecting electrode 12 are joined with a resin adhesive, the resin adhesive may include conductive particles. The tab wiring 20 is an example of a wiring member.

  In the present embodiment, three bus bar electrodes 80 are formed. As shown in FIG. 4A, the tab wiring 20 is joined to each of the three bus bar electrodes 80. In FIG. 4A, the tab wiring 20 is indicated by a broken line, and the tab wiring 20 is overlapped with and joined to the bus bar electrode 80.

  The tab wiring 20 is a long conductive wiring, for example, a ribbon-shaped metal foil. The tab wiring 20 can be produced, for example, by cutting a metal foil such as a copper foil or a silver foil, which is covered with solder, silver, or the like into a strip having a predetermined length.

[1-3. Surface protection member, back surface protection member]
The surface protection member 30 is disposed on the surface side of the solar battery cell 10 and protects the inside of the solar battery module 1 (solar battery cell 10 or the like) from an external environment such as wind and rain or an external impact. From this point of view, the surface protection member 30 may be, for example, glass having translucency and water shielding properties, a hard resin member having film-like or plate-like hard translucency properties and water shielding properties, and the like.

  The back surface protection member 40 is disposed on the back surface side of the solar battery cell 10 and protects the inside of the solar battery module 1 from the external environment. For the back surface protection member 40, for example, a film-like or plate-like resin sheet made of a resin material such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) can be used. In addition, when the solar cell module 1 is a single-sided light-receiving method, the back surface protection member 40 is good also as an opaque board or film.

[1-4. Filling member]
A filling member 50 is filled between the front surface protection member 30 and the back surface protection member 40. The front surface protection member 30, the back surface protection member 40, and the solar battery cell 10 are bonded and fixed by the filling member 50. In the present embodiment, the filling member 50 is filled so as to fill a space between the front surface protection member 30 and the back surface protection member 40.

  As shown in FIG. 2, the filling member 50 includes a front surface filling member 51 and a back surface filling member 52. Each of the surface filling member 51 and the back surface filling member 52 covers the plurality of solar cells 10 arranged in a matrix.

  The plurality of solar cells 10 are entirely covered with the filling member 50 by performing a laminating process (lamination process) while being sandwiched between, for example, a sheet-like surface filling member 51 and a back surface filling member 52.

  The surface filling member 51 before the laminating process is a resin sheet made of a translucent resin material such as ethylene vinyl acetate (EVA) or polyolefin, and includes a plurality of solar cells 10, the surface protection member 30, and the like. It is arranged between.

  The back surface filling member 52 before the laminating process is a resin sheet made of, for example, a resin material such as EVA or polyolefin, and is disposed between the plurality of solar cells 10 and the back surface protection member 40. In addition, when the solar cell module 1 is a single-sided light reception system, the back surface filling member 52 is not restricted to a translucent material, and may be comprised with coloring materials, such as a black material or a white material.

[1-5. flame]
The frame 60 is an outer frame that covers the peripheral edge of the solar cell module 1. The frame 60 is, for example, an aluminum frame (aluminum frame) made of aluminum.

[2. Solar cell structure]
Next, solar cell 10 according to the present embodiment will be described with reference to FIGS. 4A and 4B. FIG. 4B is a cross-sectional view of solar cell 10 according to the present embodiment taken along line IVB-IVB in FIG. 4A. In FIG. 4B, only the silicon substrate 10d and the recess 90 formed in the silicon substrate 10d are illustrated.

  As shown in FIG. 4A, solar cell 10 according to the present embodiment is characterized in that silicon substrate 10 d has recess 90. The recess 90 is a dent formed on the surface of the silicon substrate 10d. In general, when stress is applied, stress applied to a portion where the uniform shape such as a groove or a hole is changed increases as compared to other portions. That is, since the concave portion 90 is formed in the silicon substrate 10 d, when stress is applied to the solar battery cell 10, the stress is easily concentrated on the concave portion 90. Thereby, the position where the stress is concentrated (stress concentration position) can be controlled in the recess 90. Therefore, when an excessive stress is applied to the solar cell 10, the stress is concentrated in the recess 90, so that the solar cell 10 is easily cracked starting from the recess 90.

  Here, the direction in which the solar battery cell 10 breaks will be described. For example, a silicon substrate 10d (single crystal silicon substrate) having a (100) plane as a main surface (front and back surfaces) has two cleavage planes (for example, (011) plane and (0-11) plane) orthogonal to each other. Have. The silicon substrate 10d having such a cleavage plane has a property of being easily broken along a direction parallel to the cleavage plane. In the plan view of the solar battery cell 10, directions that travel along the cleavage plane (direction parallel to the cleavage plane) are referred to as cleavage directions 92a and 92b (also referred to as a first cleavage direction 92a and a second cleavage direction 92b). That is, in the plan view of the solar battery cell 10, the silicon substrate 10d is easily cracked along a direction parallel to the cleavage directions 92a and 92b.

  The surface of the silicon substrate 10d is a surface on the main light receiving surface side of the solar cell module 1 in the main surface of the silicon substrate 10d, and is an example of a first main surface. The back surface of the silicon substrate 10d is a surface of the silicon substrate 10d facing away from the surface of the silicon substrate 10d, and is an example of a second main surface.

  When the solar battery cell 10 is cracked, the solar battery cell 10 is easily cracked along the cleavage directions 92a and 92b of the silicon substrate 10d. In the present embodiment, the cleavage directions 92 a and 92 b are directions that form approximately 45 ° with the end sides of the solar battery cell 10. Further, the first cleavage direction 92a and the second cleavage direction 92b are orthogonal to each other. Note that the cleavage directions 92a and 92b are not limited to a direction that forms approximately 45 ° with the end side of the solar battery cell 10. For example, it may be a direction orthogonal to and parallel to the end side of the solar battery cell 10 (for example, the first cleavage direction 92a is orthogonal to the end side and the second cleavage direction 92b is parallel to the end side). However, it may be in other directions.

  As described above, in the present embodiment, when the solar battery cell 10 is cracked, the position of the concave portion 90 becomes the starting point of cracking, and cracks along the cleavage directions 92 a and 92 b of the solar battery cell 10. In a plan view with respect to the solar battery cell 10 (when the solar battery cell 10 is seen in a plan view), the concave portion 90 includes a straight line S1 and a second bus bar electrode 80b obtained by extending the first bus bar electrode 80a of the plurality of bus bar electrodes 80. It is formed in a region 91 sandwiched between stretched straight lines S2. That is, the recess 90 is formed in a region 91 sandwiched between straight lines obtained by extending the first bus bar electrode 80a and the second bus bar electrode 80b which are the two outermost bus bar electrodes. In the present embodiment, when the linear distance between adjacent bus bar electrodes 80 (the first bus bar electrode 80a and the third bus bar electrode 80c) is a distance D [mm], the recess 90 is formed in the region 91 in the first bus bar electrode. An imaginary line 93 connecting the end of 80a and the end of the third bus bar electrode 80c is formed at an inner position of D / 2 [mm] or more. More specifically, the recess 90 is formed in the longitudinal direction of the bus bar electrode 80 from each of two virtual lines 93 connecting the end of the first bus bar electrode 80a and the end of the third bus bar electrode 80c in the region 91. Is formed at an inner position of D / 2 [mm] or more.

  Thereby, when the crack 90 starts from the concave portion 90 along the cleavage directions 92 a and 92 b, the crack intersects the bus bar electrode 80 in plan view. That is, the bus bar electrode 80 is included in each broken region. In other words, when the concave portion 90 is formed inward from the virtual line 93 connecting the end portions of the bus bar electrode 80 by D / 2 or more, and cracked along the cleavage directions 92a and 92b starting from the concave portion 90 In addition, it is possible to suppress formation of a region that does not include the bus bar electrode 80 in each of the broken regions. In addition, the recessed part 90 may be formed in the edge contained in the area | region 91, for example. As a result, a region that does not include the bus bar electrode 80 is less likely to occur when the concave portion 90 formed at the end side is the starting point and the crack is broken along the cleavage directions 92a and 92b.

  The first bus bar electrode 80a is an example of one wiring, and the second bus bar electrode 80b is an example of the other wiring. Further, the adjacent bus bar electrodes 80 are not limited to the first bus bar electrode 80a and the third bus bar electrode 80c. For example, the distance D may be a linear distance between the second bus bar electrode 80b and the third bus bar electrode 80c. The distance D is not limited to the linear distance between the adjacent bus bar electrodes 80. For example, the distance D is the linear distance between the two outermost bus bar electrodes 80 (the first bus bar electrode 80a and the second bus bar electrode 80b). It is good.

  Moreover, since the stress concentration position cannot be controlled unless the concave portion 90 is formed in the silicon substrate 10d, a plurality of cracks may be formed in the solar battery cell starting from an arbitrary position. Thereby, depending on the position of the starting point of the crack, there is a possibility that a region that is not electrically connected (electrically divided) to the bus bar electrode 80 may be generated. For example, the region that is not electrically connected is a region that is formed by four cracks and that does not include the bus bar electrode 80 in the region. Thereby, since the received light charge generated in the region cannot be collected, the output of the solar battery cell is lowered.

  Note that the phrase “not electrically connected to the bus bar electrode 80” means that the bus bar electrode 80 is not electrically connected via the finger electrode 70 or the transparent electrode, for example. That is, even if the solar cell 10 is broken and a region not including the bus bar electrode 80 is generated, the region including the bus bar electrode 80 and the region not including the bus bar electrode 80 are electrically connected via the finger electrode 70 or the transparent electrode. If connected to the solar cell 10, the solar battery cell 10 can collect received light charges generated in a region not including the bus bar electrode 80.

  In addition, the bus bar electrode 80 may be broken due to the solar cell 10 being cracked. The bus bar electrode 80 is an electrode capable of outputting a voltage corresponding to the charge collected on the solar battery cell 10 to an external circuit. Therefore, even if the bus bar electrode 80 is cracked due to cracking of the solar battery cell 10, the solar battery cell 10 can output a voltage to an external circuit. That is, even if the bus bar electrode 80 is broken, the solar battery cell 10 can suppress a decrease in output. Specifically, as described above, each of the bus bar electrodes 80 is joined to the tab wiring 20. That is, the bus bar electrode 80 and the tab wiring 20 are electrically connected. Thereby, even if the bus bar electrodes 80 (for example, the first bus bar electrodes 80a) are cracked due to the crack of the solar battery cell 10, the broken bus bar electrodes 80 (for example, the cracked first bus bar electrodes 80a) are not connected to each other. Are electrically connected. Thereby, even if the bus bar electrode 80 is cracked, the solar battery cell 10 can collect current. Therefore, if the bus bar electrode 80 is included in the cracked region, the solar battery cell 10 can collect current. In other words, when the solar battery cell 10 is cracked, by forming the recess 90 so that the bus bar electrode 80 is included in all the cracked regions, a decrease in output can be suppressed even if the solar battery cell 10 is cracked. .

  In the present embodiment, one recess 90 is formed in the region 91. Specifically, one recess 90 is formed in a region sandwiched between a straight line S1 extending from the first bus bar electrode 80a and a straight line extending from the third bus bar electrode 80c. The number of recesses 90 formed in the region 91 is, for example, 2 × (n−1) or less when the number of bus bar electrodes 80 is n (n is an integer of 2 or more).

  In the present embodiment, since there are three bus bar electrodes 80, the number of formed recesses 90 is four or less. Each of the four or less recesses 90 is formed in the region 91. For example, in a plan view with respect to the solar battery cell 10, a region sandwiched between straight lines extending adjacent bus bar electrodes (for example, a straight line S <b> 1 extending the first bus bar electrode 80 a and a straight line extending the third bus bar electrode 80 c). Two recesses 90 may be formed in each of the first and second regions, and a region sandwiched between the straight line S2 extending the second bus bar electrode 80b and the straight line extending the third bus bar electrode 80c. For example, one concave portion 90 may be formed on each edge included in a region sandwiched between straight lines obtained by extending adjacent bus bar electrodes 80. In addition, for example, two recesses 90 may be formed at a position D / 2 or more inward from the end side in a region sandwiched between straight lines extending adjacent bus bar electrodes 80. That is, a region sandwiched by straight lines extending adjacent bus bar electrodes (for example, a region sandwiched by straight lines S1 extending the first bus bar electrode 80a and straight lines extending the third bus bar electrode 80c, and the second bus bar electrode When the straight line S2 extending 80b and the region sandwiched between the straight lines extending the third bus bar electrode 80c are divided into four, a recess 90 may be formed in each region.

  In addition, it is preferable that the recessed part 90 currently formed in the photovoltaic cell 10 is formed only in the area | region 91. FIG. Thereby, the dent of area | regions other than the area | region 91 becomes a starting point, and it can suppress that the photovoltaic cell 10 is cracked. When the solar cell 10 is cracked starting from a position other than the region 91, there is a high possibility that a region not electrically connected to the bus bar electrode 80 is generated depending on the position of the starting point. That is, since the concave portion 90 is formed only in the region 91, the solar battery cell 10 is cracked starting from the concave portion 90 in the region 91, so that a decrease in the output of the solar battery cell 10 can be suppressed.

  In the present embodiment, the shape of the recess 90 in plan view is a substantially circular shape. Note that the shape of the recess 90 in plan view is not limited to a substantially circular shape. For example, the shape of the recess 90 in a plan view may be a shape having an apex angle such as a substantially triangular shape. Thereby, when a stress is applied to the solar battery cell 10, the stress can be more concentrated in the recess 90. In addition, the size (for example, diameter) of the recessed part 90 is not specifically limited in the planar view of the photovoltaic cell 10. Further, the apex angle is not particularly limited. It may be an obtuse angle, an acute angle, or a right angle.

  Next, the cross-sectional shape of the recess 90 will be described with reference to FIG. 4B. As shown in FIG. 4B, the cross-sectional shape of the recess 90 is, for example, a substantially inverted triangular shape. The cross-sectional shape of the recess 90 may be, for example, a substantially rectangular shape or a substantially arc shape, or other shapes. For example, the cross-sectional shape of the recess 90 may be a shape having an acute angle. Further, the recess 90 is formed deeper than, for example, a groove-shaped wire mark (saw mark) formed in the silicon substrate 10d. The wire trace is a groove formed on the front surface and the back surface of the silicon substrate 10d by the wire when the silicon ingot is sliced with a wire using an apparatus such as a wire saw to produce the silicon substrate 10d. That is, the recess 90 according to the present embodiment is a groove different from the wire trace. The depth of the silicon substrate 10d is a depth defined by the surface of the silicon substrate 10d (the surface on the Z-axis plus side) and the valley of the recess 90 in FIG. 4B. The depth of the wire trace is a depth defined by the surface of the silicon substrate 10d and the valley of the wire trace in FIG. 4B. Moreover, the recessed part 90 is formed deeper than the texture structure formed in the silicon substrate 10d, for example.

  In addition, although the recessed part 90 demonstrated the example currently formed in the surface of the photovoltaic cell 10 in this Embodiment, it is not limited to this. For example, the recessed part 90 may be formed in the back surface of the photovoltaic cell 10, and may be formed in both surfaces of the surface and the back surface. That is, the recessed part 90 should just be formed in at least one surface of a surface and a back surface. In addition, the surface of the photovoltaic cell 10 is a surface on the main light receiving surface side in the solar cell module 1 among the principal surfaces of the photovoltaic cell 10. Moreover, the back surface of the solar battery cell 10 is a surface of the solar battery cell 10 facing away from the surface of the solar battery cell 10.

  Moreover, even if the solar cell 10 is cracked in the solar cell module 1 including the plurality of solar cells 10 according to the present embodiment and the tab wiring 20 that electrically connects the solar cells 10 to each other, It can suppress that the output of the battery cell 10 falls. That is, it can suppress that an output falls as the solar cell module 1. FIG. In addition, the solar cell module 1 should just be the solar cell 10 mentioned above at least 1 among the several photovoltaic cell with which the said solar cell module 1 is provided. Thereby, when the stress is added to the solar cell module 1, the fall of the output of the solar cell module 1 can be suppressed.

[3. Groove part manufacturing method]
Then, the manufacturing method which forms the recessed part 90 in the surface of the silicon substrate 10d is demonstrated using FIG. FIG. 5 is a diagram showing an example in which the concave portion 90 is formed by laser processing. In FIGS. 5A and 5B, a laser processing apparatus including a laser oscillator, an optical system such as a condenser lens, a table for fixing a workpiece, and the like is omitted. A laser beam L to be irradiated and a silicon substrate 10d as a workpiece are illustrated.

  FIG. 5A shows an example in which the surface of the silicon substrate 10d is irradiated with the laser beam L. FIG. For example, the laser beam L is irradiated to a position where the concave portion 90 of the silicon substrate 10d is formed. As a result, the position of the silicon substrate 10d irradiated with the laser beam L melts or evaporates, thereby forming a recess 90 on the surface of the silicon substrate 10d. The position where the laser beam L is irradiated is determined in consideration of the position where the bus bar electrode 80 is formed. When a plurality of recesses 90 are formed, the position of each recess 90 is irradiated with the laser beam L.

  FIG. 5B is a view showing the silicon substrate 10d in which the concave portion 90 is formed by irradiating the laser beam L as shown in FIG. A recess 90 is formed at the position irradiated with the laser beam L in FIG. FIG. 5B shows an example in which the shape of the recess 90 in a plan view (viewed from the Z-axis direction) is a substantially circular shape.

  Laser processing has little influence on the silicon substrate 10d, and the recess 90 can be formed at low cost. The type of laser used for laser processing is not particularly limited. For example, a gas laser such as a carbon dioxide laser or a solid state laser such as a YAG (yttrium, aluminum, garnet) laser is used. The type of laser, the output of the laser, and the like may be appropriately determined depending on the material to be processed, thickness, processing accuracy, and the like.

  FIG. 5C is a perspective view of the solar battery cell 10 having the recess 90. Specifically, it is a perspective view of the solar battery cell 10 in which electrodes and the like are formed on the silicon substrate 10d shown in FIG. As shown in FIG. 5C, the solar battery cell 10 is sandwiched between a straight line S1 obtained by extending the first bus bar electrode 80a, which is the outermost bus bar electrode 80, and a straight line S2 obtained by extending the second bus bar electrode 80b. A recessed portion 90 is provided in the region 91 formed.

  Moreover, the process of forming the recessed part 90 should just be performed in the process of forming the photovoltaic cell 10 from the silicon substrate 10d. For example, the formation of the recess 90 may be performed before the texture structure is formed on the silicon substrate 10d, or may be performed after the texture structure is formed.

  In addition, although the example which forms the recessed part 90 by laser processing was demonstrated above, the method of forming the recessed part 90 is not limited to this. For example, the recess 90 may be formed by grinding, or another method may be used. Moreover, although the example which forms the substantially circular recessed part 90 by laser processing was demonstrated above, even if the planar view shape of the recessed part 90 is other than a substantially circular shape, the recessed part 90 can be formed by laser processing.

(Embodiment 2)
Next, the solar cell 100 according to Embodiment 2 will be described with reference to FIG. Solar cell 100 according to the present embodiment differs from solar cell 10 according to Embodiment 1 in the shape of the recess. In the present embodiment, the matters described in the first embodiment are omitted, and the description will focus on differences from the first embodiment.

  FIG. 6 is a plan view showing an example of the recess 190 formed in the solar battery cell 100 according to the present embodiment. As shown in FIG. 6, the concave portion 190 of the first embodiment is that the concave portion 190 is formed so as to penetrate from the front surface to the back surface of the solar battery cell 10 (from the first main surface to the second main surface of the silicon substrate 10 d). Different from 90.

  The recess 190 is a notch formed so as to penetrate from the front surface to the back surface of the solar battery cell 100. The shape of the recess 190 in plan view is, for example, a substantially triangular shape. In addition, the substantially triangular shape means an imaginary line (in the drawing) that forms a top portion 193 when one end of the straight portion 191 and the straight portion 192 is in contact with each other, and connects the other end of the straight portion 191 and the straight portion 192 in plan view. 1, a straight line portion 191, and a straight line portion 192. In FIG. 6, the top 193 is located in a direction toward the inner side of the solar battery cell 100 in plan view.

  Further, for example, when viewed at the atomic level, a case where the top portion 193 has a flat shape or a curvature (for example, a U shape) is also included in a substantially triangular shape. Moreover, when the angle of the linear part 191 and the linear part 192 with respect to the edge of the photovoltaic cell 10 in planar view with respect to the photovoltaic cell 10 is formed differently, it is included in a substantially triangular shape. Furthermore, the case where the end side and the other end of the straight portion 191 and the straight portion 192 are connected with a curvature is also included in a substantially triangular shape. The shape of the recess 190 in plan view is not limited to a substantially triangular shape. For example, the shape of the recess 190 in plan view may be a rectangle, a polygon, a circle, or other shapes. Further, the angle (vertical angle) formed by the straight line portion 191 and the straight line portion 192 is not particularly limited. It may be an obtuse angle, an acute angle, or a right angle. The apex angle may have a curvature.

  In the present embodiment, one recess 190 is formed on the end side included in region 91. More specifically, recess 190 is an edge included in a region sandwiched by straight lines extending adjacent bus bar electrodes 80 (in this embodiment, first bus bar electrode 80a and third bus bar electrode 80c), and One is formed at a substantially central position of the end side. Note that the number of formed recesses 190 is not limited to one. A plurality of the recesses 190 may be formed. Further, the position where the recess 190 is formed is not limited to the end side included in the region 91. The recess 190 may be formed in the region 91. More specifically, the recess 190 may be formed in the region 91 and at a position that does not overlap the finger electrode 70 or the bus bar electrode 80 in plan view. For example, you may form the recessed part 190 of this Embodiment in the position of the recessed part 90 shown in Embodiment 1. FIG.

  Since the recess 190 is formed so as to penetrate from the front surface to the back surface of the solar battery cell 100, when stress is applied to the solar battery cell 100, the stress tends to concentrate on the recess 190. And it becomes easy to generate | occur | produce a crack from the recessed part 190 to which stress concentrated and added. Moreover, in this Embodiment, since the recessed part 190 has the top part 193 in planar view, it becomes easy to concentrate stress on the said top part 193. FIG. And when stress concentrates on the top part 193, it becomes easy to generate | occur | produce a crack from the said top part 193. Further, the cracking direction is the direction along the cleavage directions 92a and 92b as in the first embodiment.

  The manufacturing method for forming the recess 190 is the same as that in the first embodiment, and the description thereof is omitted.

(Embodiment 3)
Then, the photovoltaic cell 200 which concerns on Embodiment 3 is demonstrated using FIG. Solar cell 200 according to the present embodiment is different from solar cell 100 according to Embodiment 2 in that groove 290 is connected to recess 190.

  FIG. 7 is a plan view showing an example of the recess 190 and the groove 290 formed in the solar battery cell 200 according to the present embodiment. In addition, the recessed part 190 is the same as the recessed part of Embodiment 2, and description is abbreviate | omitted.

  In the present embodiment, two grooves 290 are formed from the top 193 of the recess 190. More specifically, one end of each of the two groove portions 290 in the longitudinal direction is connected to the top portion 193 of the concave portion 190. That is, one end of the groove portion 290 is formed in the region 91. And in this Embodiment, each of the other end of the edge part of the elongate direction of the groove part 290 is connected to the different edge of the photovoltaic cell 200. FIG.

  The groove part 290 is formed deeper than the wire mark, for example. That is, the groove part 290 is a groove different from the wire trace. The groove 290 may be formed so as to intersect the wire trace. Moreover, the groove part 290 may be formed from the dent which does not penetrate like the recessed part 90 of Embodiment 1. FIG. In that case, for example, the groove 290 may be formed to have a depth substantially equal to a recess that does not penetrate (for example, the recess 90 of the first embodiment).

  As in the second embodiment, the recess 190 is preferably formed at a substantially central position of the end side included in a region sandwiched by straight lines extending adjacent bus bar electrodes 80. Accordingly, the groove 290 formed from the recess 190 is easily formed so as to intersect with at least one bus bar electrode 80. That is, when the solar battery cell 200 is cracked along the groove portion 290, it is possible to suppress the generation of a region that does not include the bus bar electrode 80 in the solar battery cell 200, that is, a region that is not electrically connected to the bus bar electrode 80. can do. Therefore, even if the solar cell 200 according to the present embodiment is cracked, it is possible to suppress the output of the solar cell 200 from being lowered.

  The groove 290 is not limited to being formed from the top 193 of the recess 190. Moreover, the number of the groove parts 290 formed is not limited to two. For example, the number of groove portions 290 formed from one recess 190 is four or less. For example, when the recess is formed in the vicinity of the center of the solar battery cell 200 in plan view as in the first embodiment, four grooves are formed along the first cleavage direction 92a or the second cleavage direction 92b from the recess. 290 is formed.

  For example, each of the two groove portions 290 is formed along the first cleavage direction 92a or the second cleavage direction 92b in plan view. That is, the groove part 290 is connected to the recessed part 190, and is formed in the relationship of about 45 degrees with the edge of the photovoltaic cell 200 in planar view. In the present embodiment, the groove 290 is formed in a substantially linear shape, but is not limited to this. For example, the groove 290 may be formed in a substantially arc shape.

  In addition, each of the other ends of the groove portion 290 is not limited to being formed over the end side of the solar battery cell 200 (connected to the end side). The groove part 290 should just be formed along cleavage direction 92a, 92b, and does not need to be formed over an edge. For example, the groove part 290 may be formed only in the region 91. Thereby, the processing time which forms the groove part 290 can be shortened.

  By forming the groove 290, when stress is applied to the solar battery cell 200, the stress is concentrated not only on the recess 190 but also on the groove 290. That is, cracks are generated starting from the recesses 190 and are easily cracked in the direction in which the grooves 290 are formed. Thereby, the direction which the photovoltaic cell 200 is cracked can be controlled more accurately. In addition, it is preferable that the groove part 290 is formed in the substantially linear form from a viewpoint of controlling the cracking direction.

  For example, the groove part 290 is formed by irradiating the position where the groove part 290 is formed with the laser beam L along the shape of the groove part 290.

(Effects etc.)
Solar cell 10 according to one embodiment of the present invention is provided with a crystalline silicon substrate 10d and a light receiving charge that is provided on a first main surface of silicon substrate 10d and is generated in a light receiving region on silicon substrate 10d. A plurality of finger electrodes 70, and n (n is an integer of 2 or more) bus bar electrodes (wirings) that are provided orthogonal to the finger electrodes 70 and collect light-receiving charges generated in the light-receiving region on the silicon substrate 10d. ) 80 and one or more recesses 90 formed on at least one of the first main surface and the second main surface facing away from the first main surface. Each of the one or more recesses 90 includes a straight line S1 extending from the first bus bar electrode (one wiring) 80a of the two outermost bus bar electrodes (wirings) 80 in a plan view with respect to the solar battery cell 10. The second bus bar electrode (the other wiring) 80b is formed in a region 91 sandwiched between extended straight lines S2.

  Thereby, when a stress is applied to the solar battery cell 10, the stress is easily concentrated on the recess 90 formed on the surface of the silicon substrate 10d. That is, the stress concentration position can be controlled by forming the recess 90. Therefore, when the solar battery cell 10 is stressed and cracked, the solar battery cell 10 is easily cracked starting from the recess 90 (stress concentration position).

  Further, the cracking direction of the solar battery cell 10 is a direction along the cleavage directions 92a and 92b of the silicon substrate 10d. By forming the recess 90 in the region 91, when the solar cell 10 is cracked along the cleavage directions 92a and 92b starting from the recess 90, there is a high possibility that the bus bar electrode 80 is included in each of the cracked regions. Become. By including the bus bar electrode 80 in each cracked region, it is possible to collect charges generated in each cracked region. That is, current collection is possible even when the solar battery cell 10 is broken. Therefore, even when stress is applied to the solar battery cell 10, it is possible to suppress a decrease in output.

  In addition, each of the one or more recesses 90 is deeper than the groove-shaped wire mark formed in the silicon substrate 10d. Further, a texture structure is formed on the first main surface of the silicon substrate 10d, and each of the recesses 90 is deeper than the texture structure.

  Thereby, when stress is added to the photovoltaic cell 10, it can suppress that the photovoltaic cell 10 is cracked from a wire trace or a texture structure. That is, the solar cell 10 is easily cracked starting from the recess 90. Therefore, it becomes easy to control the stress concentration position, that is, the position of the starting point at which the solar battery cell 10 breaks.

  Further, the one or more recesses 90 are formed on the end sides of the solar battery cell 10 included in the region 91.

  Thereby, when the photovoltaic cell 10 is cracked along the cleavage directions 92a and 92b starting from the recess 90, it is possible to suppress the generation of a region that does not include the bus bar electrode 80.

  Moreover, the one or more recessed parts 90 are formed in the position of the approximate center of an edge.

  Thereby, when the photovoltaic cell 10 is further cracked along the cleavage directions 92a and 92b starting from the recess 90, it is possible to suppress the generation of a region that does not include the bus bar electrode 80 (wiring). .

  Further, when the linear distance between two adjacent bus bar electrodes 80 (wiring) is D, one or more recesses 90 are D / 2 or more from a virtual line 93 connecting the ends of the bus bar electrodes 80 in the region 91. It is formed at the inner position.

  Thereby, when the photovoltaic cell 10 is cracked along the cleavage directions 92 a and 92 b starting from the recess 90, the crack intersects the bus bar electrode 80. That is, the bus bar electrode 80 is included in each broken region. Therefore, it can suppress that the area | region where the bus-bar electrode 80 is not contained generate | occur | produces.

  The number of one or more recesses 90 formed in the region 91 is 2 × (n−1) or less.

  As a result, when a crack is generated starting from the plurality of recesses 90, it is possible to suppress the generation of a region that is surrounded by each crack and does not include the bus bar electrode 80.

  Further, each of the one or more recesses 90 is formed only in the region 91.

  Thereby, it can suppress that the dent except the area | region 91 becomes a starting point, and the photovoltaic cell 10 is cracked. When the solar cell 10 is cracked starting from a position other than the region 91, there is a high possibility that a region not including the bus bar electrode 80 is generated depending on the position of the starting point. That is, the output of the solar battery cell 10 decreases. On the other hand, since the concave portion 90 is formed only in the region 91, the solar battery cell 10 can suppress the occurrence of a region that does not include the bus bar electrode 80 when the solar battery cell 10 is broken. Therefore, the fall of the output of the photovoltaic cell 10 can be suppressed.

  Further, the one or more recesses 190 penetrate from the first main surface to the second main surface.

  Thereby, when a stress is applied to the solar battery cell 100, the stress is more likely to be concentrated in the recessed portion 190 that passes therethrough.

  Furthermore, it has the groove part 290 connected to the 1 or more recessed part 190, and the groove part 290 is formed in the substantially linear shape or the substantially circular arc shape along the cleavage direction 92a, 92b of the photovoltaic cell 200 in planar view. ing.

  As a result, cracks are generated starting from the recesses 190 and are easily cracked in the direction in which the grooves 290 are formed. That is, the direction in which the solar battery cell 200 is cracked can be controlled more accurately in the direction along the cleavage directions 92a and 92b.

  The wiring is a bus bar electrode 80.

  Thereby, it can suppress that an output falls even if a photovoltaic cell cracks by forming a recessed part in the area | region 91 pinched by the straight line which extended the bus-bar electrode 80. FIG.

  The silicon substrate 10d is a single crystal silicon substrate.

  Thereby, when the silicon substrate 10d is a single crystal silicon substrate, a reduction in output can be suppressed even if the solar battery cell is cracked.

  Moreover, the solar cell module 1 which concerns on 1 aspect of embodiment is a solar cell module provided with a several photovoltaic cell and the wiring member which electrically connects an adjacent photovoltaic cell. And at least 1 of the several photovoltaic cell is the photovoltaic cell 10,100,200 mentioned above.

  Thereby, even if stress is added to the solar cells 10, 100, and 200 included in the solar cell module 1 and the solar cells 10, 100, and 200 are cracked, a decrease in the output of the solar cells 10, 100, and 200 is suppressed. Is done. Therefore, it can suppress that an output falls as the solar cell module 1. FIG.

  A method for manufacturing a solar battery cell according to one aspect of the embodiment is a method for manufacturing the above-described solar battery cells 10, 100, 200, and includes a step of forming recesses 90, 190 by laser processing.

  By using laser processing, the above-described concave portions 90 and 190 can be formed at a low cost with little influence on the silicon substrate 10d. Similarly, the groove 290 may be formed by laser processing.

(Other variations)
As mentioned above, although the photovoltaic cell and solar cell module which concern on this invention were demonstrated based on embodiment, this invention is not limited to the said embodiment.

  For example, although an example in which a plurality of finger electrodes and n (three in the above embodiment) bus bar electrodes are formed on the surface of the solar battery cell has been described, the present invention is not limited thereto. For example, instead of the bus bar electrode 80, wire wiring (also referred to as first wire wiring) may be formed. The wire wiring is connected to the finger electrode 70 formed in the solar battery cell via a conductive adhesive, and is arranged in a substantially straight line along the direction intersecting the finger electrode 70. For example, the wire wiring is disposed along a direction substantially orthogonal to the finger electrode 70. The wire wiring is, for example, a long conductive wiring.

  The wire wiring further collects the carriers collected by the finger electrodes 70. At least two wire wirings are formed. The recesses described above are formed, for example, in a region sandwiched between straight lines obtained by extending the outermost wire wiring. The wire wiring (first wire wiring) is an example of wiring.

  Furthermore, the 1st wire wiring which an adjacent photovoltaic cell has may be electrically connected through the 2nd wire wiring different from a 1st wire wiring, for example. For example, the second wire wiring includes the end portion of the first wire wiring disposed on the surface of one of the two adjacent solar cells and the other of the two adjacent solar cells. The end of the first wire wiring disposed on the back surface of the solar cell is electrically connected. The second wire wiring is an example of a wiring member. The first wire wiring and the second wire wiring may be integrally formed.

  Thereby, even when stress is applied to the solar battery cell having the wire wiring and it is cracked, a current collecting effect can be exhibited. Therefore, even if the solar battery cell having the wire wiring is cracked, a decrease in output can be suppressed.

  Moreover, you may form the recessed part mentioned above, or a recessed part and a groove part in a back junction type photovoltaic cell. In the back junction solar cell, a collector electrode for collecting carriers is formed on the back surface of the solar cell. Specifically, a first collector electrode that collects carriers (electrons) and a second collector electrode that collects carriers (holes) are formed. For example, the first collector electrode and the second collector electrode are formed in a comb shape. That is, each of the first collector electrode and the second collector electrode is formed along a direction that is commonly connected to the plurality of first electrodes formed in parallel with the first electrode and orthogonal to the first electrode, And a second electrode that further collects carriers collected by the first electrode. In this case, the first electrode is an example of a finger electrode, and the second electrode is an example of a bus bar electrode (wiring).

  In addition, the number of the 1st collector electrode and the 2nd collector electrode which are formed is not specifically limited. One set may be formed, or a plurality of sets may be formed. In addition, since the second electrode (wiring) is formed on each of the first collector electrode and the second collector electrode, two or more second electrodes are formed in the back junction solar cell. For example, the concave portion is formed in a region sandwiched by straight lines obtained by extending the second electrode located at the outermost portion.

  Thereby, even when stress is applied to the back junction solar cell and it is cracked, when the tab wiring is connected to the second electrode, a current collecting effect can be exhibited. Therefore, even if the back junction solar cell is cracked, a decrease in output can be suppressed.

  In the above embodiment, an example in which the crystalline silicon substrate is a single crystal silicon substrate has been described, but the present invention is not limited to this. For example, the crystalline silicon substrate may be a polycrystalline silicon substrate. Polycrystalline silicon is composed of a plurality of single crystal silicons. Therefore, when the crystalline silicon substrate is a polycrystalline silicon substrate, a crystal grain boundary (interface) is formed between adjacent single crystal silicons. The cleavage direction in the polycrystalline silicon substrate corresponds to, for example, a direction along a crystal grain boundary (a direction parallel to the crystal grain boundary) in plan view. The groove is formed, for example, along the cleavage direction, that is, along the crystal grain boundary.

  Thereby, also in a polycrystalline silicon substrate, a recessed part becomes a starting point and a crack generate | occur | produces. When the polycrystalline silicon substrate is cracked along the cleavage direction, a recess is formed so that a region not including the bus bar electrode 80 is not generated, so that a decrease in output can be suppressed even if the solar cell is cracked. . Note that the positions of the recesses formed in the polycrystalline silicon substrate are within the region sandwiched by straight lines extending the bus bar electrodes 80, as in the case of the single crystal silicon substrate (similar to the above embodiment). For example, it is in a region sandwiched by straight lines extending the outermost bus bar electrode 80.

  Moreover, although the said embodiment demonstrated the example in which the finger electrode and the bus-bar electrode were formed in the surface and back surface of a photovoltaic cell, it is not limited to this. For example, when the solar cell module is a single-sided light receiving system, a solid electrode that covers the entire back surface side of the solar cell may be formed on the back surface of the solar cell. In that case, the tab wiring is joined on the solid electrode. For example, at least two tab wires are provided. In addition, the position of the recessed part currently formed in the photovoltaic cell which has a solid electrode on the back surface is in the area | region pinched by the straight line which extended | stretched the outermost tab wiring, for example.

  Thereby, there exists an effect similar to the said embodiment.

  In addition, it is realized by arbitrarily combining the components and functions in each embodiment without departing from the gist of the present invention, or forms obtained by subjecting each embodiment to various modifications conceived by those skilled in the art. Forms are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Solar cell module 10, 100, 200 Solar cell 10d n-type single crystal silicon substrate (silicon substrate)
20 Tab wiring (wiring member)
70 Finger electrode 80 Bus bar electrode (wiring)
80a First bus bar electrode (one wiring)
80b Second bus bar electrode (the other wiring)
90, 190 Concave portion 91 Region 92a First cleavage direction (cleavage direction)
92b Second cleavage direction (cleavage direction)
93 Virtual line 290 Groove S1, S2 Straight line D Distance

Claims (14)

A silicon substrate having crystallinity;
A plurality of finger electrodes that are provided on the first main surface of the silicon substrate and collect light-receiving charges generated in a light-receiving region on the silicon substrate;
N wirings (n is an integer of 2 or more) provided to be orthogonal to the finger electrodes and collect the received charge generated in the light receiving region on the silicon substrate;
One or more recesses formed on at least one of the first main surface and the second main surface facing away from the first main surface;
Each of the one or more recesses is in a region sandwiched between a straight line extending from one of the two outermost wirings and a straight line extending from the other wiring in a plan view with respect to the solar battery cell. Formed solar cells. The solar cell according to claim 1, wherein each of the one or more recesses is deeper than a groove-like wire mark formed in the silicon substrate. A texture structure is formed on the first main surface of the silicon substrate,
The solar cell according to claim 1, wherein each of the one or more recesses is deeper than the texture structure. The solar cell according to any one of claims 1 to 3, wherein the one or more recesses are formed on an end side of the solar cell included in the region. The solar cell according to claim 4, wherein the one or more recesses are formed at a position substantially in the center of the end side. If the linear distance between two adjacent wires is D,
The sun according to any one of claims 1 to 3, wherein the one or more recesses are formed at a position D / 2 or more inward from a virtual line connecting the ends of the wiring in the region. Battery cell. The number of the 1 or more recessed part currently formed in the said area | region is 2x (n-1) or less, The photovoltaic cell of any one of Claims 1-6. Each of the said 1 or more recessed part is formed only in the said area | region. The photovoltaic cell of any one of Claims 1-7. The photovoltaic cell according to any one of claims 1 to 8, wherein the one or more recesses penetrate from the first main surface to the second main surface. And a groove connected to the one or more recesses,
The solar cell according to any one of claims 1 to 9, wherein the groove is formed in a substantially linear shape or a substantially arc shape along a cleavage direction of the solar cell in a plan view. The solar cell according to claim 1, wherein the wiring is a bus bar electrode. The solar cell according to claim 1, wherein the silicon substrate is a single crystal silicon substrate. A solar cell module comprising a plurality of solar cells and a wiring member that electrically connects the adjacent solar cells,
At least one of the plurality of solar cells is the solar cell according to any one of claims 1 to 12. A solar cell module. It is a manufacturing method of the photovoltaic cell according to any one of claims 1 to 12,
The manufacturing method of a photovoltaic cell including the process of forming the said recessed part by laser processing.

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