Solar cell element and solar cell module

Abstract

The solar cell element includes a semiconductor substrate having a first surface and a second surface, and a first electrode on the first surface. The first electrode includes a bus bar portion (311b) disposed along the first direction and a plurality of finger portions (311f) arranged in the first direction. The bus bar portion (311b) includes a first region (A1) and a second region (A2), which are different from each other in position in the first direction. The plurality of fingers (311f) include a plurality of first fingers (311f1) connected to the first region (A1) and a plurality of second fingers (311f2) connected to the second region (A2). Each first finger (311f1) includes a first portion (P1) connected to the first region (A1) and a second portion (P2) separated from the first region (A1). Each second finger (311f2) includes a third portion (P3) connected to the second region (A2) and a fourth portion (P4) separated from the second region (A2). The width of the first portion (P1) is larger than that of the third portion (P3).

Description

[0001] Cross-reference to related applications

[0002] The present application claims priority from Japanese Patent Application No. 2022-139718 (filed on September 2, 2022), the disclosure of which is incorporated herein in its entirety for reference. Technical Field

[0003] The present disclosure relates to a solar cell element and a solar cell module. Background Art

[0004] There is a solar cell module having a plurality of solar cell elements, a plurality of wiring materials and a sealing material. In the solar cell module, the plurality of wiring materials electrically connect two adjacent solar cell elements among the plurality of solar cell elements, respectively. The sealing material is arranged in a state of covering the plurality of solar cell elements.

[0005] Each solar cell element is provided with a grid-shaped electrode (also referred to as a grid electrode), for example, on the upper surface side of the solar cell element (for example, refer to the descriptions of Patent Documents 1 and 2). The grid electrode has a plurality of bus bar portions and a plurality of finger portions. The plurality of bus bar portions are arranged, for example, approximately in parallel on the upper surface side of the solar cell element. The plurality of finger portions are arranged, for example, approximately in parallel on the upper surface side of the solar cell element. Each finger portion is, for example, approximately orthogonal to the plurality of bus bar portions and is thinner than each of the plurality of bus bar portions.

[0006] In recent years, there has been an increasing demand for improved power generation efficiency and reliability in solar cell elements and solar cell modules.

[0007] Prior Art Literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2005-116906

[0010] Patent Document 2: Japanese Patent Application No. 2015-528645 Summary of the invention

[0011] Disclosed are a solar cell element and a solar cell module.

[0012] One mode of a solar cell element comprises a semiconductor substrate and a first electrode. The semiconductor substrate has a first surface and a second surface opposite to the first surface. The first electrode is located on the first surface. The first electrode includes a bus bar portion and a plurality of finger portions. The bus bar portion is arranged along a first direction of the first surface. The plurality of finger portions are arranged in the first direction. The plurality of finger portions are linear portions thinner than the bus bar portion, and are connected to the bus bar portion in a state of crossing the bus bar portion. The bus bar portion includes a first region and a second region whose positions are different from each other in the first direction. The plurality of finger portions include a plurality of first finger portions connected to the first region and a plurality of second finger portions connected to the second region. The plurality of first finger portions respectively include a first portion connected to the first region and a second portion separated from the first region. The plurality of second finger portions respectively include a third portion connected to the second region and a fourth portion separated from the second region. The width of the first portion is greater than the width of the third portion.

[0013] One embodiment of a solar cell module includes a solar cell section and a sealing material covering the solar cell section. The solar cell section includes a first solar cell element, a second solar cell element, and a first wiring material. The first solar cell element and the second solar cell element are separated in a first direction and arranged in a second direction opposite to the first direction. The first wiring material includes a portion joined to the first solar cell element and a portion joined to the second solar cell element. The first solar cell element includes the solar cell element of the above embodiment. The bus bar section has a first end and a second end opposite to the first end in the first direction. The first region includes a first end portion of the bus bar section located on the first end side. The plurality of first finger-shaped portions include two or more first finger-shaped portions connected to the first end portion. The second end is located closer to the second solar cell element than the first end in the first direction. The first wiring material has a third end and a fourth end in the first direction. The third end is located in a region along the first solar cell element. The fourth end is located in a region along the second solar cell element. The first wiring material is in a state of being joined to the bus bar section along the first direction. The first wiring material includes a portion on the third end side joined to the first end portion.

[0014] One embodiment of a solar cell module includes a solar cell section and a sealing material covering the solar cell section. The solar cell section includes a first solar cell element, a second solar cell element, and a first wiring material. The first solar cell element and the second solar cell element are separated in a first direction and arranged in a second direction opposite to the first direction. The first wiring material includes a portion joined to the first solar cell element and a portion joined to the second solar cell element. The first solar cell element includes the solar cell element of the above embodiment. The bus bar section has a first end and a second end opposite to the first end in the first direction. The second end is located closer to the second solar cell element than the first end in the first direction. The bus bar section includes a first end portion located on the first end side. The first region includes a second end portion of the bus bar section located on the second end side. The plurality of first finger portions include two or more first finger portions connected to the second end portion. The first wiring material has a third end and a fourth end in the first direction. The third end is located in a region along the first solar cell element. The fourth end is located in a region along the second solar cell element. The first wiring material is in a state of being joined to the bus bar section along the first direction. The first wiring material includes a portion on the third end side joined to the first end portion.

[0015] One embodiment of a solar cell module includes a solar cell section and a sealing material covering the solar cell section. The solar cell section includes a first solar cell element, a second solar cell element, and a first wiring material. The first solar cell element and the second solar cell element are separated in a first direction and arranged in a second direction opposite to the first direction. The first wiring material includes a portion bonded to the first solar cell element and a portion bonded to the second solar cell element. The first solar cell element includes the solar cell element of the above embodiment. The bus bar section includes a first island portion and a second island portion arranged in the first direction, and includes a connecting portion connecting the first island portion and the second island portion. The plurality of finger portions include a third finger portion connected to the connecting portion. The third finger portion includes: two fifth portions, which are respectively connected to the third direction side of the connecting portion intersecting the first direction and along the first surface and the fourth direction side opposite to the third direction; and a sixth portion, which is separated from the connecting portion. In the first direction, the width of each of the two fifth portions is greater than the width of the sixth portion. The two fifth portions have a fifth end located in the fourth direction and a sixth end located in the third direction. In the third direction, a length from the fifth end to the sixth end is greater than a width of the first wiring material. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a diagram schematically showing an example of the structure when the first element surface of the solar cell element according to the first embodiment is viewed from above.

[0017] Figure 2 This is a diagram schematically showing an example of the structure when the second element surface of the solar cell element according to the first embodiment is viewed from above.

[0018] Figure 3 It is schematically indicated Figure 1 as well as Figure 2 FIG. 1 is a diagram showing an example of an imaginary cross-section of a solar cell element taken along line III-III.

[0019] Figure 4 It is schematically indicated Figure 1 A diagram showing an example of the structure of section IV of a solar cell element.

[0020] Figure 5 It is a plan view schematically showing an example of the appearance of the solar cell module according to the first embodiment when viewed from above.

[0021] Figure 6 It is schematically indicated Figure 5 FIG. 4 is a diagram showing an example of an imaginary cross-section of a solar cell module taken along line VI-VI.

[0022] Figure 7 It is schematically represented in Figure 1 FIG. 1 is a diagram showing an example of a state in which a first wiring material is joined to a bus bar portion in portion IV of a solar cell element.

[0023] Figure 8 This is a diagram schematically showing an example of a state of a virtual cross section during the production of a specific example of a method for producing a solar cell element.

[0024] Fig. 9 This is a diagram schematically showing an example of a state of a virtual cross section during the production of a specific example of a method for producing a solar cell element.

[0025] Fig.10 This is a diagram schematically showing an example of a state of a virtual cross section during the production of a specific example of a method for producing a solar cell element.

[0026] Fig.11 This is a diagram schematically showing an example of a state of a virtual cross section during the production of a specific example of a method for producing a solar cell element.

[0027] Fig.12 This is a diagram schematically showing an example of a state of a virtual cross section during the production of a specific example of a method for producing a solar cell element.

[0028] Fig.13 This is a diagram schematically showing an example of a state of a virtual cross section during the manufacturing process of a specific example of the method for manufacturing the solar cell module according to the first embodiment.

[0029] Fig.14 This is a diagram schematically showing an example of a state of a virtual cross section during the manufacturing process of a specific example of the method for manufacturing the solar cell module according to the first embodiment.

[0030] Fig.15 The solar cell element according to the second embodiment is schematically shown. Figure 1 A diagram showing an example of the structure of a portion corresponding to portion IV of a solar cell element.

[0031] Fig.16 is a schematic diagram showing the solar cell element according to the second embodiment. Figure 1 FIG. 1 is a diagram showing an example of a state in which a first wiring material is joined to a bus bar portion in a portion corresponding to portion IV of a solar cell element.

[0032] Fig.17 The solar cell element according to the third embodiment is schematically shown. Figure 1 A diagram showing an example of the structure of a portion corresponding to portion IV of a solar cell element.

[0033] Fig.18 is a schematic diagram showing the solar cell element according to the third embodiment. Figure 1 FIG. 1 is a diagram showing an example of a state in which a first wiring material is joined to a bus bar portion in a portion corresponding to portion IV of a solar cell element.

[0034] Fig.19 is a schematic diagram showing a solar cell element according to another embodiment. Figure 1 A diagram showing an example of the structure of a portion corresponding to portion IV of a solar cell element.

[0035] Fig. 20 is a schematic diagram showing a solar cell element according to another embodiment. Figure 1 A diagram showing an example of the structure of a portion corresponding to portion IV of a solar cell element.

[0036] Fig.21 is a schematic diagram showing a solar cell element according to another embodiment. Figure 1A diagram showing an example of the structure of a portion corresponding to portion IV of a solar cell element.

[0037] Fig. 22 is a schematic diagram showing a solar cell element according to another embodiment. Figure 1 A diagram showing an example of the structure of a portion corresponding to portion IV of a solar cell element.

[0038] Fig.23 is a schematic diagram showing a solar cell element according to another embodiment. Figure 1 A diagram showing an example of the structure of a portion corresponding to portion IV of a solar cell element.

[0039] Fig.24 is a schematic diagram showing a solar cell element according to another embodiment. Figure 1 A diagram showing an example of the structure of a portion corresponding to portion IV of a solar cell element.

[0040] Fig.25 This is a diagram schematically showing an example of a structure when the second element surface of a solar cell element according to another embodiment is viewed from above. DETAILED DESCRIPTION

[0041] There is a solar cell module having a plurality of solar cell elements, a plurality of wiring materials and a sealing material. In the solar cell module, the plurality of wiring materials electrically connect two adjacent solar cell elements among the plurality of solar cell elements, respectively. The sealing material is arranged in a state of covering the plurality of solar cell elements.

[0042] Each solar cell element is provided with a grid-shaped electrode (also referred to as a grid electrode), for example, on the upper surface side of the solar cell element. The grid electrode has a plurality of bus bar portions and a plurality of finger portions. The plurality of bus bar portions are, for example, arranged approximately in parallel on the upper surface side of the solar cell element. Each of the plurality of finger portions has, for example, a linear form thinner than the plurality of bus bar portions. In addition, in the case where the width of the plurality of bus bar portions is not constant, the linear form thinner than the plurality of bus bar portions means that each of the plurality of finger portions has a linear form thinner than the maximum width of the plurality of bus bar portions. The plurality of finger portions are, for example, arranged approximately in parallel on the upper surface side of the solar cell element. Each finger portion is, for example, approximately orthogonal to the plurality of bus bar portions.

[0043] Each wiring material is joined to the bus bar portion in the grid electrode by welding or the like.

[0044] However, regarding solar cell elements, for example, it is conceivable that the amount of sunlight received that contributes to power generation can be increased by thinning grid electrodes that block sunlight.

[0045] However, if the grid electrode is made too thin, disconnection may easily occur in the grid electrode.

[0046] An important factor that easily causes disconnection is, for example, that in a solar cell module installed outdoors, humidity stress caused by humidity and / or rainfall may reduce the bonding strength between the bus bar portion and the finger portion and the semiconductor substrate.

[0047] As the next important factor, the temperature rise corresponding to the irradiation of sunlight and power generation during the day and the temperature drop at night are repeatedly generated. In this case, the expansion caused by the temperature rise and the contraction caused by the temperature drop are repeatedly generated in each part of the solar cell module. At this time, due to the difference in thermal expansion coefficients corresponding to the materials constituting each part of the solar cell module, stress is repeatedly generated in the solar cell module. For example, due to the expansion and contraction of the wiring material and the sealing material, the wiring material applies stress to the busbar part.

[0048] Due to the above two important factors, the bus bar portion may be separated from the semiconductor substrate.

[0049] For example, when the bus bar portion is partially peeled off from the semiconductor substrate starting from the end of the bus bar portion located on the end side of the long side direction of the wiring material, the portion of the bus bar portion peeled off from the semiconductor substrate is easily displaced. As a result, a particularly large shear stress is generated in the portion of the finger portion connected to the bus bar portion (also referred to as a connecting portion).

[0050] Here, for example, if the width of the connecting portion of the finger is too small, the finger is more likely to break at the connecting portion. In addition, if the use period of the solar cell module and the solar cell element becomes longer, the finger is more likely to break due to fatigue at the connecting portion due to repeated stress concentration.

[0051] In addition, it is considered that the smaller the width of the connecting portion of the finger, the higher the possibility of stress concentration in the connecting portion of the finger, and the smaller the width of the connecting portion of the finger, the more likely it is that the finger will be broken in a short time due to the progression of cracks starting from the stress concentration portion in the connecting portion of the finger.

[0052] If the finger-shaped portion is disconnected, the output characteristics of the solar cell module are degraded. The deterioration of the output characteristics of the solar cell module is also referred to as degradation of the output characteristics of the solar cell module.

[0053] Here, for example, increasing the width of the connection portion in each finger-shaped portion may be considered. However, if the width of the connection portion in each finger-shaped portion is increased, the amount of sunlight received that contributes to power generation in the solar cell element decreases.

[0054] Therefore, there is room for improvement in terms of increasing power generation efficiency and reliability in solar cell elements and solar cell modules.

[0055] Therefore, the inventors of the present disclosure have developed a technology capable of improving power generation efficiency and reliability for a solar cell element and a solar cell module. In this regard, first to third embodiments and other embodiments will be described below with reference to the drawings.

[0056] In the drawings, the same reference numerals are used for parts having the same or substantially the same structure and function. Therefore, substantially repeated descriptions are appropriately omitted in the following description. The drawings are schematically shown. Figures 1 to 25 The right-handed XYZ coordinate system is marked in FIG. In the XYZ coordinate system, the direction along the long side direction of the bus bar portion 311b of the solar cell element 31 is the -Y direction as the first direction. The direction opposite to the first direction is set as the +Y direction as the second direction. The direction along the long side direction of the finger-shaped portion 311f of the solar cell element 31 is set as the +X direction as the third direction. The direction opposite to the third direction is set as the -X direction as the fourth direction. The direction perpendicular to the first element surface F1 of the solar cell element 31 (also referred to as the normal direction) which is orthogonal to both the -Y direction and the +X direction is set as the +Z direction.

[0057] <1. First embodiment>

[0058] <1-1. Solar cell element>

[0059] Reference Figures 1 to 4 The solar cell element 31 according to the first embodiment will be described.

[0060] The solar cell element 31 can convert light energy into electric energy. The solar cell element 31 has a plate shape, for example.

[0061] like Figures 1 to 3 As shown, the solar cell element 31 has a first element surface F1 and a second element surface F2. The second element surface F2 is a surface on the opposite side to the first element surface F1. Figures 1 to 3In the example, the first element surface F1 is in a state facing the +Z direction, and the second element surface F2 is in a state facing the -Z direction. For example, the first element surface F1 has a function as a surface mainly incident on light (the light-receiving surface is also called the front surface). For example, the second element surface F2 has a function as the back surface opposite to the light-receiving surface. The first element surface F1 and the second element surface F2 each have a rectangular shape such as a roughly square. Here, the shape of each of the first element surface F1 and the second element surface F2 is not limited to a rectangle. For example, in each of the first element surface F1 and the second element surface F2, each corner can be an arc shape or a shape with a C-chamfered corner. The first element surface F1 and the second element surface F2 each have a roughly square shape with a side length of about 150 millimeters (mm) to 250 mm. The first element surface F1 and the second element surface F2 can each have a roughly rectangular shape, for example.

[0062] like Figure 1 as well as Figure 3 As shown in FIG. 3 , the solar cell element 31 includes a semiconductor substrate 310 and a first electrode 311. Figure 2 as well as Figure 3 As shown, the solar cell element 31 includes a second electrode 312 .

[0063] <1-1-1. Semiconductor substrate>

[0064] The semiconductor substrate 310 has, for example, a first surface 310a and a second surface 310b. The first surface 310a is a surface on the first element surface F1 side. The second surface 310b is a surface on the second element surface F2 side. In other words, the second surface 310b is a surface on the opposite side to the first surface 310a. The semiconductor substrate 310 has, for example, a plate-like shape.

[0065] The semiconductor substrate 310 may be a crystalline semiconductor such as crystalline silicon, an amorphous semiconductor such as amorphous silicon, or a compound semiconductor using four elements such as copper, indium, gallium, and selenium or two elements such as cadmium and tellurium. Here, it is assumed that the semiconductor substrate 310 is crystalline silicon. In this case, Figure 3As shown, the semiconductor substrate 310 mainly includes: a region (also referred to as a first type region) 310f having a semiconductor of a first conductivity type; and a region (also referred to as a second type region) 310s having a semiconductor of a second conductivity type opposite to the first conductivity type. The first type region 310f is, for example, located on the second surface 310b side of the semiconductor substrate 310. The second type region 310s is, for example, located on the surface portion of the first surface 310a side of the semiconductor substrate 310. The surface portion may be a portion of the semiconductor substrate 310 that forms the first surface 310a along the first surface 310a. Here, for example, when the first conductivity type is p-type, the second conductivity type is n-type. For example, when the first conductivity type is n-type, the second conductivity type is p-type. Thus, the semiconductor substrate 310 has, for example, a pn junction portion located at the interface between the first type region 310f and the second type region 310s.

[0066] The first surface 310a and the second surface 310b each have a rectangular shape, such as a roughly square. Here, the shape of each of the first surface 310a and the second surface 310b is not limited to a rectangular shape. For example, in each of the first surface 310a and the second surface 310b, each corner may be an arc shape, or may have a shape with a C-chamfered corner. The first surface 310a and the second surface 310b each have a roughly square shape, such as a length of one side of about 150 mm to 250 mm. The first surface 310a and the second surface 310b may also each have a roughly rectangular shape, such as a roughly rectangular shape. The thickness of the semiconductor substrate 310 is, for example, set to about 50 μm (micrometers) to 250 μm.

[0067] <1-1-2. First electrode>

[0068] The first electrode 311 is located, for example, on the first surface 310a of the semiconductor substrate 310. In other words, the first electrode 311 is located on the first element surface F1 side of the solar cell element 31. Here, the length (also referred to as thickness) of the first electrode 311 in the +Z direction is set to about 0.5 μm to 50 μm, for example.

[0069] The first electrode 311 includes, for example, a bus bar portion 311 b as a first output portion and a plurality of finger portions 311 f as a plurality of first collector portions. More specifically, for example, the first electrode 311 includes a plurality of bus bar portions 311 b and a plurality of finger portions 311 f.

[0070] Each bus bar portion 311b is located along the -Y direction as the first direction, and the first direction is along the first surface 310a. In other words, each bus bar portion 311b has a long side direction along the -Y direction as the first direction. From another point of view, each bus bar portion 311b has an elongated shape along the -Y direction as the first direction. For example, a plurality of bus bar portions 311b are arranged in the +X direction as the third direction. For example, the plurality of bus bar portions 311b have the same structure. In manufacturing a solar cell module 100 (see Figure 5 ), the first wiring material 32 (see FIG. 1 ) for electrically connecting two adjacent solar cell elements 31 is joined to the bus bar portion 311 b. Figure 5 ).

[0071] The plurality of finger-shaped portions 311f are arranged in the -Y direction as the first direction. The plurality of finger-shaped portions 311f are linear portions thinner than the bus bar portion 311b. Each finger-shaped portion 311f is connected to the plurality of bus bar portions 311b in a state of crossing the plurality of bus bar portions 311b. In other words, the plurality of finger-shaped portions 311f are connected to the bus bar portion 311b in a state of crossing the bus bar portion 311b. Each finger-shaped portion 311f is arranged, for example, along the +X direction as the third direction, and the third direction is along the first surface 310a. In other words, each finger-shaped portion 311f has, for example, a long side direction along the +X direction as the third direction. From another point of view, each finger-shaped portion 311f has a thin and long linear shape along the +X direction as the third direction.

[0072] exist Figure 1 In the example, five bus bar portions 311b as a plurality of substantially parallel bus bar portions 311b and a plurality of substantially parallel finger portions 311f exist in a substantially orthogonal state. In other words, the first electrode 311 may also be a grid-shaped electrode. Here, the number of bus bar portions 311b in the first electrode 311 is not limited to five. The number of bus bar portions 311b in the first electrode 311 may be any number from 5 to 15, for example.

[0073] Here, if Figure 1 As shown, the first electrode 311 may include, for example, an auxiliary electrode 311a provided along the outer edge portion in the -X direction and an auxiliary electrode 311a provided along the outer edge portion in the +X direction on the first surface 310a. Each auxiliary electrode 311a, for example, connects a plurality of substantially parallel finger-shaped portions 311f to each other. In addition, for example, the anti-reflection film 314 may be located in an area where the first electrode 311 is not present on the second type region 310s of the semiconductor substrate 310. The anti-reflection film 314 may be, for example, an insulating film made of silicon nitride or the like. For example, Figure 1 as well as Figure 3 As shown, the passivation film 313 may be present between the second type region 310s of the semiconductor substrate 310 and the anti-reflection film 314. The passivation film 313 may be a thin film made of, for example, an oxide such as aluminum oxide or a nitride.

[0074] For example, when the main component of the material of the first electrode 311 is silver, the first electrode 311 can be formed by applying a silver paste into a desired shape by screen printing or the like, and then firing the silver paste. In this specification, the main component refers to a component with the largest (highest) ratio (also referred to as content) among the components constituting a substance. The silver paste is, for example, a metal paste containing a metal powder including silver as a main component, an organic vehicle, and glass frit. The plurality of busbar portions 311b, the plurality of finger portions 311f, and the two auxiliary electrodes 311a in the first electrode 311 may be formed by different processes or by the same process.

[0075] <1-1-3. Second electrode>

[0076] The second electrode 312 is located on the second element surface F2 side of the semiconductor substrate 310 , for example.

[0077] The second electrode 312 includes, for example, a second output portion 312 b and a second power collecting portion 312 c. More specifically, for example, the second electrode 312 includes a plurality of second output portions 312 b and a second power collecting portion 312 c.

[0078] Each second output portion 312b is arranged along the -Y direction as the first direction. For example, the plurality of second output portions 312b are arranged in the +X direction as the third direction. Each second output portion 312b includes, for example, a plurality of electrode portions arranged in a row. Figure 2 In the example, each second output portion 312b includes, for example, 7 electrode portions arranged in a row.

[0079] The second collector portion 312c is located on the second element surface F2 side of the semiconductor substrate 310. The second collector portion 312c is located on substantially the entire surface of the region where the second output portion 312b does not exist, except for a portion where the second output portion 312b overlaps with the second collector portion 312c and is connected to each other, on the second element surface F2 side of the semiconductor substrate 310. In addition, the second collector portion 312c does not need to be located on substantially the entire surface, and may exist in a lattice shape, for example.

[0080] Here, for example, Figure 2 as well as Figure 3As shown, a passivation film 313 may be present between the first type region 310f of the semiconductor substrate 310 and the second output portion 312b and the second collector portion 312c. The passivation film 313 may be, for example, a thin film made of oxides such as aluminum oxide or nitrides. In this case, the passivation film 313 is located between the first type region 310f and the second output portion 312b and the second collector portion 312c in a desired pattern. Furthermore, a film (also referred to as a protective film) 315 for protecting the passivation film 313 may be present between the passivation film 313 and the second collector portion 312c. The protective film 315 may be, for example, a thin film made of oxides such as silicon oxide. The protective film 315 is located between the passivation film 313 and the second collector portion 312c in a desired pattern. The protective film 315 may be, for example, Figure 3 As shown, it does not exist between the passivation film 313 and the second output portion 312b. In this case, the protective film 315 has a plurality of hole portions where the second output portion 312b is located. In addition, for example, the protective film 315 may also exist between the passivation film 313 and the second output portion 312b. The passivation film 313 and the protective film 315, for example, have a plurality of through holes for making a part of the second collector portion 312c contact with the first type region 310f. The first type region 310f, for example, has a region (the high concentration region is also called a BSF (Back Surface Field) region) 310t in which the concentration of the first conductive type doping element is higher than that of other regions of the first type region 310f in the portion of the surface layer in contact with the second collector portion 312c.

[0081] For example, when the main component of the material of the second output portion 312b is silver, the silver paste is applied into a desired shape by screen printing or the like, and then the silver paste is fired, thereby forming the second output portion 312b. For example, when the main component of the material of the second collector portion 312c is aluminum, the aluminum paste is applied into a desired shape by screen printing or the like, and then the aluminum paste is fired, thereby forming the second collector portion 312c. The aluminum paste may be a metal paste containing a metal powder including aluminum as a main component, an organic vehicle, and glass frit.

[0082] <1-1-4. Structure and characteristics of the first electrode>

[0083] <<Bus bar structure>>

[0084] like Figure 4As shown, for example, the bus bar portion 311b includes a first area A1 and a second area A2. The positions of the first area A1 and the second area A2 in the -Y direction as the first direction are different from each other. Here, the situation where the positions in the -Y direction as the first direction are different from each other may also be referred to as the Y coordinates being different from each other. In other words, the Y coordinates of the first area A1 and the second area A2 are different from each other. In addition, the situation where the positions in the -Y direction as the first direction are different from each other may also be referred to as the distances measured from one end of the bus bar portion 311b in the Y direction being different from each other. In other words, the distances of the first area A1 and the second area A2 measured from one end of the bus bar portion 311b in the Y direction are different from each other.

[0085] The bus bar portion 311b has a first end (also referred to as a first end) E1 and a second end (also referred to as a second end) E2 in the -Y direction, which is the first direction. In this case, in the bus bar portion 311b, the second end E2 is located on the opposite side of the first end E1 in the -Y direction, which is the first direction. In other words, the bus bar portion 311b has a pair of first ends E1 and second ends E2 in the Y direction. Figure 4 In the example of , the first end E1 is the end of the bus bar portion 311b in the -Y direction as the first direction, and the second end E2 is the end of the bus bar portion 311b in the +Y direction as the second direction. In addition, for example, the bus bar portion 311b includes a portion (also referred to as a first end portion) Ep1 of the bus bar portion 311b located on the first end E1 side. For example, the bus bar portion 311b includes a portion (also referred to as a second end portion) Ep2 of the bus bar portion 311b located on the second end E2 side.

[0086] In the first embodiment, the first region A1 includes, for example, a portion (also referred to as a first end portion) Ep1 of the bus bar portion 311 b located on the first end E1 side. The second region A2 includes, for example, a portion of the bus bar portion 311 b different from the first end portion Ep1.

[0087] In the first embodiment, for example, the bus bar portion 311 b includes a plurality of island-shaped portions (the island-shaped portions are also referred to as land portions) Ip1 arranged along the −Y direction as the first direction. Figure 4In the example of , the bus bar portion 311b includes 7 island portions Ip1 as a plurality of island portions Ip1. The 7 island portions Ip1 include a first island portion Ip11, a second island portion Ip12, a third island portion Ip13, a fourth island portion Ip14, a fifth island portion Ip15, a sixth island portion Ip16, and a seventh island portion Ip17. The first island portion Ip11, the second island portion Ip12, the third island portion Ip13, the fourth island portion Ip14, the fifth island portion Ip15, the sixth island portion Ip16, and the seventh island portion Ip17 are arranged in the order described along the -Y direction as the first direction. In other words, the bus bar portion 311b includes the first island portion Ip11 and the second island portion Ip12 arranged along the -Y direction as the first direction. Here, the number of island portions Ip1 in the bus bar portion 311b is not limited to 7. For example, the number of the island-shaped portions Ip1 in the bus bar portion 311 b may be any number from three to thirty.

[0088] The first end portion Ep1 constituting the first region A1 includes, for example, the island portion Ip1 located closest to the first end E1 among the plurality of island portions Ip1 in one bus bar portion 311b, that is, the seventh island portion Ip17. In addition, the second region A2 includes an island portion Ip1 different from the seventh island portion Ip17 among the plurality of island portions Ip1 in one bus bar portion 311b. Figure 4 In the example of FIG. 3 , in one bus bar portion 311 b, the second region A2 includes all island portions Ip1 except the seventh island portion Ip17 among the plurality of island portions Ip1. More specifically, the second region A2 includes the first island portion Ip11, the second island portion Ip12, the third island portion Ip13, the fourth island portion Ip14, the fifth island portion Ip15, and the sixth island portion Ip16.

[0089] For example, when looking down at the first element surface F1, each island-shaped portion Ip1 has a rectangular shape as an example of a rectangular shape. Here, the shape of each island-shaped portion Ip1 is not limited to a rectangle. For example, the corners of each island-shaped portion Ip1 may be arc-shaped or may have a shape with a cut corner. The length (also referred to as the width) W1 of the island-shaped portion Ip1 in the +X direction as the third direction is set to about 0.25 mm to 4 mm, for example. The length (also referred to as the length) of the island-shaped portion Ip1 in the -Y direction as the first direction is set to about 0.25 mm to 10 mm, for example.

[0090] In the first embodiment, for example, the bus bar portion 311b includes a portion (also referred to as a connecting portion) Cp1 connecting two adjacent island portions Ip1. More specifically, for example, the bus bar portion 311b includes a plurality of connecting portions Cp1 connecting a plurality of island portions Ip1 in sequence. Figure 4 In the example of , the bus bar portion 311b includes six connecting portions Cp1 that sequentially connect the seven island portions Ip1. More specifically, the bus bar portion 311b includes a connecting portion Cp1 that connects the first island portion Ip11 and the second island portion Ip12. The bus bar portion 311b includes a connecting portion Cp1 that connects the second island portion Ip12 and the third island portion Ip13. The bus bar portion 311b includes a connecting portion Cp1 that connects the third island portion Ip13 and the fourth island portion Ip14. The bus bar portion 311b includes a connecting portion Cp1 that connects the fourth island portion Ip14 and the fifth island portion Ip15. The bus bar portion 311b includes a connecting portion Cp1 that connects the fifth island portion Ip15 and the sixth island portion Ip16. The bus bar portion 311b includes a connection portion Cp1 connecting the sixth island portion Ip16 and the seventh island portion Ip17. Here, the number of connection portions Cp1 in the bus bar portion 311b is not limited to 6. For example, the number of connection portions Cp1 in the bus bar portion 311b can be appropriately set according to the number of the plurality of island portions Ip1.

[0091] For example, when looking down at the first element surface F1, the connection portion Cp1 has an elongated shape along the -Y direction as the first direction. In other words, the connection portion Cp1 has a long side direction along the -Y direction as the first direction and a short side direction along the +X direction as the third direction. The length (also referred to as the width) of the connection portion Cp1 in the +X direction as the third direction is smaller than the length (width) W1 of the island portion Ip1 in the +X direction as the third direction. Thus, for example, the material required for forming the bus bar portion 311b can be reduced. In addition, for example, the amount of sunlight incident on the semiconductor substrate 310 and blocked by the bus bar portion 311b can be reduced. Therefore, for example, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved. Here, the width of the connection portion Cp1 is set to about 0.01 mm to 0.4 mm, for example. Furthermore, for example, when the solar cell module 100 is manufactured, if the connection portion Cp1 exists, even if the first wiring member 32 is not bonded to a part of the island portion Ip1, a decrease in the power output from the solar cell element 31 can be reduced.

[0092] In addition, Figure 4In the example, the connecting portion Cp1 is, for example, in a state of connecting the approximately central portions of the two adjacent island-like portions Ip1 in the +X direction as the third direction. More specifically, the connecting portion Cp1 between the first island-like portion Ip11 and the second island-like portion Ip12 is in a state of connecting the approximately central portions of the first island-like portion Ip11 and the second island-like portion Ip12 in the +X direction as the third direction. The connecting portion Cp1 between the second island-like portion Ip12 and the third island-like portion Ip13 is in a state of connecting the approximately central portions of the second island-like portion Ip12 and the third island-like portion Ip13 in the +X direction as the third direction. The connecting portion Cp1 between the third island-like portion Ip13 and the fourth island-like portion Ip14 is in a state of connecting the approximately central portions of the third island-like portion Ip13 and the fourth island-like portion Ip14 in the +X direction as the third direction. The connecting portion Cp1 between the fourth island portion Ip14 and the fifth island portion Ip15 is in a state of connecting the respective substantially central portions of the fourth island portion Ip14 and the fifth island portion Ip15 in the +X direction as the third direction. The connecting portion Cp1 between the fifth island portion Ip15 and the sixth island portion Ip16 is in a state of connecting the respective substantially central portions of the fifth island portion Ip15 and the sixth island portion Ip16 in the +X direction as the third direction. The connecting portion Cp1 between the sixth island portion Ip16 and the seventh island portion Ip17 is in a state of connecting the respective substantially central portions of the sixth island portion Ip16 and the seventh island portion Ip17 in the +X direction as the third direction.

[0093] Here, the second region A2 may include, for example, a plurality of connection portions Cp1. More specifically, in one bus bar portion 311b, the second region A2 may include all the connection portions Cp1.

[0094] In addition, for example, the bus bar portion 311b includes a first protruding portion Dp1 and a second protruding portion Dp2. The first protruding portion Dp1 is a portion that protrudes from the island portion Ip1 located closest to the first end E1 among the multiple island portions Ip1 in the bus bar portion 311b, that is, the seventh island portion Ip17, toward the -Y direction, which is the first direction. The second protruding portion Dp2 is a portion that protrudes from the island portion Ip1 located closest to the second end E2 among the multiple island portions Ip1 in the bus bar portion 311b, that is, the first island portion Ip11, toward the +Y direction, which is the second direction. Figure 4In the example of FIG. 1 , the first protrusion Dp1 protrudes from a substantially central portion of the seventh island portion Ip17 in the +X direction as the third direction toward the -Y direction as the first direction. The second protrusion Dp2 protrudes from a substantially central portion of the first island portion Ip11 in the +X direction as the third direction toward the +Y direction as the second direction. Here, for example, the bus bar portion 311b may not include the first protrusion Dp1 or the second protrusion Dp2.

[0095] <<Structure of the finger>>

[0096] like Figure 4 As shown, the plurality of finger-shaped portions 311f are arranged at a given pitch in the -Y direction as the first direction, for example. The given pitch is set to about 0.8 mm to 2 mm, for example. Here, for example, the interval between two adjacently arranged finger-shaped portions 311f may also slightly deviate from the given pitch.

[0097] like Figure 4 As shown, the plurality of fingers 311f include a plurality of first fingers 311f1 and a plurality of second fingers 311f2. The plurality of first fingers 311f1 are respectively connected to the first area A1 of the bus bar 311b. The plurality of second fingers 311f2 are respectively connected to the second area A2 of the bus bar 311b.

[0098] In the first embodiment, the plurality of first finger portions 311f1 include two or more first finger portions 311f1 connected to the first end portion Ep1. More specifically, the plurality of first finger portions 311f1 are respectively connected to the island portion Ip1 located closest to the first end E1 among the plurality of island portions Ip1 in one bus bar portion 311b, that is, the seventh island portion Ip17. In addition, the plurality of second finger portions 311f2 are respectively connected to the island portion Ip1 different from the seventh island portion Ip17 among the plurality of island portions Ip1 in one bus bar portion 311b.

[0099] The plurality of first finger-shaped portions 311f1 respectively include a portion (the first portion is also referred to as a first connecting portion) P1 connected to the first area A1 and a portion (the second portion is also referred to as a first thin line portion) P2 separated from the first area A1. Here, the situation where the second portion P2 is separated from the first area A1 may be renamed as the situation where the second portion P2 is not physically connected to the first area A1. In other words, the second portion P2 is not directly connected to the first area A1. In addition, the situation where the second portion P2 is separated from the first area A1 may be renamed as the situation where the second portion P2 is electrically connected to the first area A1 via the first portion P1. In other words, the second portion P2 is electrically connected to the first area A1 via the first portion P1. The length (also referred to as the width) of the first portion P1 in the -Y direction which is the first direction is greater than the length (also referred to as the width) of the second portion P2 in the -Y direction which is the first direction. Here, for example, when the solar cell module 100 is manufactured, even if the first wiring material 32 bonded to the first area A1 of the bus bar portion 311b applies a force to the first area A1, it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the first area A1 among the plurality of first finger portions 311f1. As a result, the reliability of the solar cell element 31 and the solar cell module 100 can be improved by improving durability.

[0100] Here, the width of the second portion (first thin line portion) P2 is set to, for example, about 10 μm to 100 μm. The width of the first portion (first connecting portion) P1 is set to, for example, about 1.05 to 10 times the width of the second portion (first thin line portion) P2. The length of the first portion (first connecting portion) P1 in the +X direction, which is the third direction, is set to, for example, about 0.1 mm to 3 mm.

[0101] For example, the first portion P1 is connected to the island portion Ip1 located closest to the first end E1 among the plurality of island portions Ip1 in one bus bar portion 311b, that is, the seventh island portion Ip17. More specifically, for example, each first finger portion 311f1 is connected to the +X direction side as the third direction and the -X direction side as the fourth direction of the seventh island portion Ip17, respectively. Moreover, for example, each first finger portion 311f1 includes two first portions P1 connected to the +X direction side as the third direction and the -X direction side as the fourth direction of the seventh island portion Ip17, respectively. More specifically, for example, each first finger portion 311f1 includes one first portion P1 connected to the +X direction side as the third direction of the seventh island portion Ip17, and one first portion P1 connected to the -X direction side as the fourth direction of the seventh island portion Ip17. For example, the second portion P2 is separated from the seventh island portion Ip17, which is the island portion Ip1 closest to the first end E1 among the plurality of island portions Ip1 in one bus bar portion 311b. In each first finger portion 311f1, the second portion P2 is, for example, a portion different from the first portion P1.

[0102] The plurality of second finger-shaped portions 311f2 respectively include a portion (the third portion is also referred to as the second connecting portion) P3 connected to the second area A2 and a portion (the fourth portion is also referred to as the second thin line portion) P4 separated from the second area A2. Here, the situation where the fourth portion P4 is separated from the second area A2 may be referred to as the situation where the fourth portion P4 is not physically connected to the second area A1. In other words, the fourth portion P4 is not directly connected to the second area A2. In addition, the situation where the fourth portion P4 is separated from the second area A2 may be referred to as the situation where the fourth portion P4 is electrically connected to the second area A2 via the third portion P3. In other words, the fourth portion P4 is electrically connected to the second area A2 via the third portion P3. The length (also referred to as the width) of the third portion P3 in the -Y direction as the first direction is greater than the length (also referred to as the width) of the fourth portion P4 in the -Y direction as the first direction. Here, for example, in the -Y direction as the first direction, the width of the third portion P3 is smaller than the width of the first portion P1. In other words, the width of the first portion (first connection portion) P1 of a portion of the plurality of fingers 311f, namely the first finger 311f1, is selectively increased. Thus, for example, compared with a configuration in which all the fingers 311f have the same and large width or a configuration in which all the fingers 311f have the same structure as the first finger 311f1, the amount of sunlight incident on the semiconductor substrate 310 and blocked by the plurality of second fingers 311f2 can be reduced. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved. In addition, the material required to form the plurality of fingers 311f can be reduced. From another point of view, for example, the width of the first portion P1 of the first finger 311f1 is larger than the width of the third portion P3 of the second finger 311f2. Thus, for example, when the solar cell module 100 is manufactured, even if the first wiring material 32 joined to the bus bar portion 311b applies force to the bus bar portion 311b, it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the first area A1 among the plurality of first finger portions 311f1. As a result, the reliability can be improved by improving the durability of the solar cell element 31 and the solar cell module 100. Therefore, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved.

[0103] Here, the width of the fourth portion (second thin line portion) P4 may be the same as or different from the width of the second portion (first thin line portion) P2. The width of the fourth portion (second thin line portion) P4 is, for example, set to about 10 μm to 100 μm. The width of the third portion (second connecting portion) P3 is, for example, set to about 1 to 10 times the width of the fourth portion (second thin line portion) P4. The length of the third portion (second connecting portion) P3 in the +X direction, which is the third direction, is, for example, set to about 0.1 mm to 3 mm. Here, for example, if the width of the third portion P3 is larger than the width of the fourth portion P4, when the solar cell module 100 is manufactured, even if the first wiring material 32 bonded to the second area A2 of the bus bar portion 311 b applies a force to the second area A2, the occurrence of disconnection in the third portion P3, which is the portion connected to the second area A2, of the plurality of second finger-shaped portions 311 f2 can be reduced.

[0104] For example, the third portion P3 is connected to an island portion Ip1 different from the seventh island portion Ip17 among the plurality of island portions Ip1 in one bus bar portion 311b. More specifically, for example, each second finger portion 311f2 is connected to the +X direction side as the third direction and the -X direction side as the fourth direction of an island portion Ip1 different from the seventh island portion Ip17 among the plurality of island portions Ip1 in one bus bar portion 311b. Moreover, for example, each second finger portion 311f2 includes two third portions P3 respectively connected to the +X direction side as the third direction and the -X direction side as the fourth direction of an island portion Ip1 different from the seventh island portion Ip17 among the plurality of island portions Ip1. More specifically, for example, each second finger-shaped portion 311f2 includes: a third portion P3 connected to the +X direction side as the third direction in the island-shaped portion Ip1 different from the seventh island-shaped portion Ip17; and a third portion P3 connected to the -X direction side as the fourth direction in the island-shaped portion Ip1 different from the seventh island-shaped portion Ip17. In addition, for example, the fourth portion P4 separates the island-shaped portion Ip1 different from the seventh island-shaped portion Ip17 among the plurality of island-shaped portions Ip1. In each second finger-shaped portion 311f2, the fourth portion P4 is, for example, a portion different from the third portion P3.

[0105] In addition, for example Figure 4As shown, the plurality of fingers 311f include a third finger 311f3. More specifically, the plurality of fingers 311f include a plurality of third fingers 311f3. In addition, the third finger 311f3 is connected to the connecting portion Cp1. More specifically, the plurality of third fingers 311f3 are respectively connected to the connecting portion Cp1. In addition, the third finger 311f3 includes a portion (the fifth portion is also referred to as the third connecting portion) P5 connected to the connecting portion Cp1, and a portion (the sixth portion is also referred to as the third thin line portion) P6 separated from the connecting portion Cp1. Here, the case where the sixth portion P6 is separated from the connecting portion Cp1 may be referred to as the sixth portion P6 not being physically connected to the connecting portion Cp1. In other words, the sixth portion P6 is not directly connected to the connecting portion Cp1. In addition, the case where the sixth portion P6 is separated from the connecting portion Cp1 may be referred to as the sixth portion P6 being electrically connected to the connecting portion Cp1 via the fifth portion P5. In other words, the sixth portion P6 is electrically connected to the connecting portion Cp1 via the fifth portion P5. More specifically, the plurality of third finger portions 311f3 each include a fifth portion (third connecting portion) P5 connected to the connecting portion Cp1 and a sixth portion (third thin line portion) P6 separated from the connecting portion Cp1. The length (also referred to as the width) of the fifth portion P5 in the -Y direction as the first direction is greater than the length (also referred to as the width) of the sixth portion P6 in the -Y direction as the first direction. Here, for example, if the width of the fifth portion P5 is smaller than the width of the first portion P1, the amount of sunlight incident on the semiconductor substrate 310 that is blocked by the plurality of third finger portions 311f3 is reduced. As a result, for example, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved.

[0106] Here, the width of the sixth portion (third thin line portion) P6 may be the same as or different from the width of the fourth portion (second thin line portion) P4. The width of the sixth portion (third thin line portion) P6 is set to, for example, about 10 μm to 100 μm. The width of the fifth portion (third connecting portion) P5 is set to, for example, about 1 to 10 times the width of the sixth portion (third thin line portion) P6. The length of the fifth portion (third connecting portion) P5 in the +X direction, which is the third direction, is set to, for example, about 0.1 mm to 3 mm. Here, for example, if the width of the fifth portion P5 is larger than the width of the sixth portion P6, when the solar cell module 100 is manufactured, even if the first wiring material 32 bonded to the connecting portion Cp1 in the bus bar portion 311 b applies a force to the connecting portion Cp1, the occurrence of disconnection in the fifth portion P5 connected to the connecting portion Cp1 in the plurality of third finger-shaped portions 311 f3 can be reduced.

[0107] In addition, for example, each third finger-shaped portion 311f3 is connected to the +X direction side as the third direction and the -X direction side as the fourth direction in the connecting portion Cp1. Moreover, for example, each third finger-shaped portion 311f3 includes two fifth portions P5 connected to the +X direction side as the third direction and the -X direction side as the fourth direction in the connecting portion Cp1. More specifically, for example, each third finger-shaped portion 311f3 includes one fifth portion P5 connected to the +X direction side as the third direction in the connecting portion Cp1, and one fifth portion P5 connected to the -X direction side as the fourth direction in the connecting portion Cp1. In other words, for example, the third finger-shaped portion 311f3 includes two fifth portions P5 connected to the +X direction side as the third direction and the -X direction side as the fourth direction in the connecting portion Cp1, and a sixth portion P6 separated from the connecting portion Cp1. The +X direction as the third direction is a direction intersecting the -Y direction as the first direction and along the first surface 310a. In each third finger-shaped portion 311f3, the sixth portion P6 is, for example, a portion different from the fifth portion P5. Here, for example, the two fifth portions P5 have an end portion (also referred to as a fifth end) E5 located in the -X direction, which is the fourth direction opposite to the +X direction, which is the third direction, and an end portion (also referred to as a sixth end) E6 located in the +X direction, which is the third direction. In other words, for example, the fifth portion P5 located in the -X direction, which is the fourth direction, more than the connecting portion Cp1 of the two fifth portions P5 connected to the +X direction side, which is the third direction, and the -X direction side, which is the fourth direction, respectively, has the fifth end E5 as the end portion on the opposite side to the connecting portion Cp1. For example, the fifth portion P5 located in the +X direction, which is the third direction, more than the connecting portion Cp1 of the two fifth portions P5 connected to the +X direction side, which is the third direction, and the -X direction side, which is the fourth direction, respectively, has the sixth end E6 as the end portion on the opposite side to the connecting portion Cp1.

[0108] Here, for example, when the second area A2 includes a plurality of connection portions Cp1, the plurality of second fingers 311f2 includes a plurality of third fingers 311f3.

[0109] In addition, for example Figure 4 As shown, the plurality of fingers 311f include a fourth finger 311f4 and a fifth finger 311f5.

[0110] The fourth finger-shaped portion 311f4 is connected to the first protruding portion Dp1. The fourth finger-shaped portion 311f4 includes a portion (the seventh portion is also referred to as the fourth connecting portion) P7 connected to the first protruding portion Dp1 and a portion (the eighth portion is also referred to as the fourth thin line portion) P8 separated from the first protruding portion Dp1. Here, the case where the eighth portion P8 is separated from the first protruding portion Dp1 may be referred to as the eighth portion P8 not being physically connected to the first protruding portion Dp1. In other words, the eighth portion P8 is not directly connected to the first protruding portion Dp1. In addition, the eighth portion P8 is separated from the first protruding portion Dp1 and referred to as the eighth portion P8 being electrically connected to the first protruding portion Dp1 via the seventh portion P7. In other words, the eighth portion P8 is electrically connected to the first protruding portion Dp1 via the seventh portion P7. The length (also referred to as the width) of the seventh portion P7 in the -Y direction as the first direction is greater than the length (also referred to as the width) of the eighth portion P8 in the -Y direction as the first direction. Here, for example, if the width of the seventh portion P7 is smaller than the width of the first portion P1, the amount of sunlight incident on the semiconductor substrate 310 and blocked by the plurality of fourth finger portions 311f4 can be reduced. As a result, for example, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved.

[0111] Here, the width of the eighth portion (fourth thin line portion) P8 may be the same as or different from the width of the fourth portion (second thin line portion) P4. The width of the eighth portion (fourth thin line portion) P8 is, for example, set to about 10 μm to 100 μm. The width of the seventh portion (fourth connecting portion) P7 is, for example, set to about 1 to 10 times the width of the eighth portion (fourth thin line portion) P8. The length of the seventh portion (fourth connecting portion) P7 in the +X direction, which is the third direction, is, for example, set to about 0.1 mm to 3 mm.

[0112] In addition, for example, the fourth finger-shaped portion 311f4 is connected to the +X direction side as the third direction and the -X direction side as the fourth direction of the first protruding portion Dp1, respectively. Moreover, for example, the fourth finger-shaped portion 311f4 includes two seventh portions P7 connected to the +X direction side as the third direction and the -X direction side as the fourth direction of the first protruding portion Dp1, respectively. More specifically, for example, each fourth finger-shaped portion 311f4 includes one seventh portion P7 connected to the +X direction side as the third direction of the first protruding portion Dp1 and one seventh portion P7 connected to the -X direction side as the fourth direction of the first protruding portion Dp1. In the fourth finger-shaped portion 311f4, the eighth portion P8 is, for example, a portion different from the seventh portion P7.

[0113] The fifth finger-shaped portion 311f5 is connected to the second protruding portion Dp2. The fifth finger-shaped portion 311f5 includes a portion (the ninth portion is also referred to as the fifth connecting portion) P9 connected to the second protruding portion Dp2 and a portion (the tenth portion is also referred to as the fifth thin line portion) P10 separated from the second protruding portion Dp2. Here, the situation where the tenth portion P10 is separated from the second protruding portion Dp2 may be referred to as the tenth portion P10 not being physically connected to the second protruding portion Dp2. In other words, the tenth portion P10 is not directly connected to the second protruding portion Dp2. In addition, the situation where the tenth portion P10 is separated from the second protruding portion Dp2 may be referred to as the tenth portion P10 being electrically connected to the second protruding portion Dp2 via the ninth portion P9. In other words, the tenth portion P10 is electrically connected to the second protruding portion Dp2 via the ninth portion P9. The length (also referred to as the width) of the ninth portion P9 in the -Y direction as the first direction is greater than the length (also referred to as the width) of the tenth portion P10 in the -Y direction as the first direction. Here, for example, if the width of the ninth portion P9 is smaller than the width of the first portion P1, the amount of sunlight blocked by the plurality of fifth finger portions 311f5 incident on the semiconductor substrate 310 can be reduced. As a result, for example, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved.

[0114] Here, the width of the tenth portion (fifth thin line portion) P10 may be the same as or different from the width of the fourth portion (second thin line portion) P4. The width of the tenth portion (fifth thin line portion) P10 is set to, for example, about 10 μm to 100 μm. The width of the ninth portion (fifth connecting portion) P9 is set to, for example, about 1 to 10 times the width of the tenth portion (fifth thin line portion) P10. The length of the ninth portion (fifth connecting portion) P9 in the +X direction, which is the third direction, is set to, for example, about 0.1 mm to 3 mm. Here, for example, if the width of the ninth portion P9 is larger than the width of the tenth portion P10, when the solar cell module 100 is manufactured, even if the first wiring material 32 bonded to the second protruding portion Dp2 of the bus bar portion 311 b applies a force to the second protruding portion Dp2, the occurrence of disconnection in the ninth portion P9, which is the portion of the fifth finger portion 311 f5 connected to the second protruding portion Dp2, can be reduced.

[0115] In addition, for example, the fifth finger-shaped portion 311f5 is connected to the +X direction side as the third direction and the -X direction side as the fourth direction in the second protruding portion Dp2, respectively. Also, for example, the fifth finger-shaped portion 311f5 includes two ninth portions P9 connected to the +X direction side as the third direction and the -X direction side as the fourth direction in the second protruding portion Dp2, respectively. More specifically, for example, each fifth finger-shaped portion 311f5 includes one ninth portion P9 connected to the +X direction side as the third direction in the second protruding portion Dp2 and one ninth portion P9 connected to the -X direction side as the fourth direction in the second protruding portion Dp2. In the fifth finger-shaped portion 311f5, the tenth portion P10 is, for example, a portion different from the ninth portion P9.

[0116] Here, for example, when the bus bar portion 311b does not include the first protrusion Dp1, the plurality of fingers 311f may not include the fourth finger 311f4. Also, for example, when the bus bar portion 311b does not include the second protrusion Dp2, the plurality of fingers 311f may not include the fifth finger 311f5.

[0117] <1-2. Solar cell module>

[0118] Reference Figures 5 to 7 The solar cell module 100 according to the first embodiment will be described. The solar cell module 100 according to the first embodiment is manufactured using, for example, the solar cell element 31 according to the first embodiment described above.

[0119] like Figure 5 as well as Figure 6 As shown, the solar cell module 100 includes, for example, a power generator 10. The power generator 10 has, for example, a surface 10f on which light is mainly incident (the front surface is also referred to as a light-receiving surface) and a surface 10b located on the opposite side of the front surface 10f (also referred to as a back surface).

[0120] For example, the front surface 10f is in a state of facing the +Z direction. For example, the back surface 10b is in a state of facing the -Z direction. When the solar cell module 100 is used for power generation outdoors, the +Z direction is set to face the sun in the south, for example. Figure 5 In the example of FIG. 1 , the front surface 10 f has a rectangular shape as an example of a rectangular shape.

[0121] The solar cell module 100 may further include, for example, a terminal box J1 for taking out the power generated by the power generator 10 to the outside. The terminal box J1 is located, for example, on the back surface 10b of the power generator 10. The solar cell module 100 may further include, for example, a frame 6 for protecting the outer periphery of the power generator 10. The frame 6 is, for example, arranged along the outer periphery of the power generator 10. In this case, for example, a sealing material with low moisture permeability such as a butyl resin may be further filled between the outer periphery of the power generator 10 and the frame 6.

[0122] like Figure 5 as well as Figure 6 As shown, for example, the power generator 10 includes a solar cell section 3 and a sealing material 4. Furthermore, for example, the power generator 10 includes a first protective member 1 and a second protective member 2.

[0123] <1-2-1. First protective member>

[0124] The first protective member 1 is, for example, a member for protecting the solar cell section 3 from the front surface 10f side. The first protective member 1 is, for example, in a state of constituting the front surface 10f of the power generator 10. The first protective member 1 is, for example, light-transmitting. Specifically, the first protective member 1 is, for example, light-transmitting with respect to a specific range of wavelengths. The specific range of wavelengths includes, for example, wavelengths of light that can be photoelectrically converted by the solar cell section 3. If the specific range of wavelengths includes wavelengths of light with high irradiation intensity in sunlight, the photoelectric conversion efficiency of the solar cell module 100 can be improved. Figure 6 As shown, the first protective member 1 has a first surface 1f and a second surface 1s. The first surface 1f is, for example, in a state of constituting the front surface 10f of the power generation body 10. The first surface 1f is a surface on the opposite side of the solar cell section 3. The second surface 1s is a surface on the opposite side of the first protective member 1 to the first surface 1f. The second surface 1s is opposite to the solar cell section 3. Figure 5 as well as Figure 6 In the example, the first surface 1f and the second surface 1s each have a rectangular shape as an example of a rectangle. The first protective member 1 is, for example, a flat plate or sheet-like member. The material of the flat plate-like member is, for example, a resin such as glass or polycarbonate. The material of the sheet-like member is, for example, a resin such as a weather-resistant fluorine-based resin. The weather-resistant fluorine-based resin includes, for example, fluorinated ethylene propylene copolymer (Fluorinated Ethylene Propylene: FEP), ethylene-tetrafluoroethylene copolymer (Ethylene Tetrafluoroethylene: ETFE) and / or ethylene-chlorotrifluoroethylene copolymer (Ethylene Chlorotrifluoroethylene: ECTFE).

[0125] <1-2-2. Second protective member>

[0126] The second protective member 2 is, for example, a member for protecting the solar cell section 3 from the back surface 10b side. The second protective member 2, for example, is in a state of constituting the back surface 10b of the power generator 10. The second protective member 2 may or may not be light-transmissive. Figure 6 As shown, the second protective member 2 has a third surface 2f and a fourth surface 2s. The fourth surface 2s is, for example, in a state of constituting the back surface 10b of the power generation body 10. The fourth surface 2s is a surface on the opposite side of the solar cell section 3. The third surface 2f is a surface on the opposite side of the fourth surface 2s in the second protective member 2. The third surface 2f is opposite to the solar cell section 3. Figure 5 as well as Figure 6 In the example of the third surface 2f and the fourth surface 2s, the third surface 2f and the fourth surface 2s each have a rectangular shape as an example of a rectangle. The second protective member 2 is, for example, a sheet-like or flat-plate-like member. The sheet-like member is, for example, a back plate constituting the back surface 10b. The material of the back plate is, for example, a resin. In addition, the flat-plate-like member is, for example, a glass plate or a polycarbonate plate.

[0127] <1-2-3. Solar cell unit>

[0128] The solar cell section 3 is located, for example, between the first protective member 1 and the second protective member 2. In other words, the solar cell section 3 is in a state of facing the first protective member 1 and facing the second protective member 2 in the Z direction.

[0129] like Figure 5 as well as Figure 6 As shown, the solar cell section 3 includes, for example, a plurality of solar cell elements 31. The plurality of solar cell elements 31 are located between the second surface 1s of the first protective member 1 and the third surface 2f of the second protective member 2. From another point of view, the plurality of solar cell elements 31 are arranged in a state opposite to the second surface 1s of the first protective member 1. In addition, the plurality of solar cell elements 31 are arranged along the second surface 1s of the first protective member 1. In other words, the plurality of solar cell elements 31 are in a state of being arranged in a plane along the second surface 1s of the first protective member 1. Figure 5 as well as Figure 6 In the example of FIG. 1 , a plurality of solar cell elements 31 exist in a state of being two-dimensionally arranged along a virtual XY plane.

[0130] More specifically, for example, in each of the plurality of solar cell elements 31, the first element surface F1 faces the second surface 1s of the first protective member 1, and the second element surface F2 faces the third surface 2f of the second protective member 2. Figure 6In the example, the first element surface F1 is in a state facing the +Z direction, and the second element surface F2 is in a state facing the -Z direction.

[0131] The solar cell section 3 includes, for example, a first wiring material 32. In addition, the solar cell section 3 includes, for example, a second wiring material 33. Figure 5 as well as Figure 6 In the example shown in FIG. 5 , the solar cell section 3 includes a plurality of first wiring members 32 and a plurality of second wiring members 33 .

[0132] The solar cell section 3 includes, for example, a plurality of solar cell strings 30. The plurality of solar cell strings 30 are arranged in, for example, the +X direction which is the third direction. Figure 5 as well as Figure 6 In the example of FIG. 3 , the solar cell section 3 includes four solar cell strings 30 as the plurality of solar cell strings 30. More specifically, Figure 5 As shown, the four solar cell strings 30 include a first solar cell string 30a, a second solar cell string 30b, a third solar cell string 30c, and a fourth solar cell string 30d. The first solar cell string 30a, the second solar cell string 30b, the third solar cell string 30c, and the fourth solar cell string 30d are arranged in the +X direction as the third direction in the order described.

[0133] exist Figure 5 as well as Figure 6In the example, the first solar cell string 30a and the third solar cell string 30c have substantially the same structure, and the second solar cell string 30b and the fourth solar cell string 30d have substantially the same structure. Moreover, the structures of the two solar cell strings 30 adjacent to each other in the +X direction as the third direction have a substantially quadratic symmetric rotational symmetric relationship in which the structures are substantially the same when rotated 180 degrees around the axis of symmetry parallel to the Z axis. For example, the first solar cell string 30a and the second solar cell string 30b have a substantially quadratic symmetric rotational symmetric relationship in which the structures are substantially the same when rotated 180 degrees around the axis of symmetry parallel to the Z axis. The second solar cell string 30b and the third solar cell string 30c have a substantially quadratic symmetric rotational symmetric relationship in which the structures are substantially the same when rotated 180 degrees around the axis of symmetry parallel to the Z axis. The third solar cell string 30c and the fourth solar cell string 30d have a substantially quadratic symmetric rotational symmetric relationship in which the structures are substantially the same when rotated 180 degrees around the axis of symmetry parallel to the Z axis. In other words, although not strictly speaking, the second solar cell string 30b and the fourth solar cell string 30d can be regarded as having the following structures: based on the first solar cell string 30a and the third solar cell string 30c, the first direction is changed from the -Y direction to the +Y direction, and the second direction is changed from the +Y direction to the -Y direction. In order to avoid complicating the description below, when describing the structure of the solar cell string 30, the structure of the first solar cell string 30a is sometimes used as a representative example.

[0134] Each of the plurality of solar cell strings 30 includes, for example, two or more solar cell elements 31 and a plurality of first wiring members 32. In each solar cell string 30, the two or more solar cell elements 31 are arranged in, for example, the +Y direction which is the second direction. Figure 5 as well as Figure 6 In the example of FIG. 1 , each solar cell string 30 includes six solar cell elements 31 separated in the −Y direction as the first direction, as two or more solar cell elements 31. More specifically, as Figure 5 as well as Figure 6As shown, the six solar cell elements 31 include a first solar cell element 31a, a second solar cell element 31b, a third solar cell element 31c, a fourth solar cell element 31d, a fifth solar cell element 31e, and a sixth solar cell element 31f. The first solar cell element 31a, the second solar cell element 31b, the third solar cell element 31c, the fourth solar cell element 31d, the fifth solar cell element 31e, and the sixth solar cell element 31f are arranged in the +Y direction as the second direction in the order described. In other words, the first solar cell element 31a and the second solar cell element 31b are separated in the -Y direction as the first direction and arranged in the +Y direction as the second direction. The second solar cell element 31b and the third solar cell element 31c are separated in the -Y direction as the first direction and arranged in the +Y direction as the second direction. The third solar cell element 31c and the fourth solar cell element 31d are separated in the -Y direction as the first direction and arranged in the +Y direction as the second direction. The fourth solar cell element 31d and the fifth solar cell element 31e are separated in the -Y direction as the first direction and arranged in the +Y direction as the second direction. The fifth solar cell element 31 e and the sixth solar cell element 31 f are separated in the −Y direction as the first direction and are arranged in the +Y direction as the second direction.

[0135] The plurality of first wiring members 32 are in a state of electrically connecting two mutually adjacent solar cell elements 31 among two or more solar cell elements 31 in each solar cell string 30. Specifically, for example, in the first solar cell string 30a and the third solar cell string 30c, the first wiring member 32 connects the second output portion 312b located on the second element surface F2 of one solar cell element 31 and the bus bar portion 311b located on the first element surface F1 of another solar cell element 31 adjacent to the one solar cell element 31 in the -Y direction as the first direction. In addition, for example, in the second solar cell string 30b and the fourth solar cell string 30d, the first wiring member 32 connects the second output portion 312b located on the second element surface F2 of one solar cell element 31 and the bus bar portion 311b located on the first element surface F1 of another solar cell element 31 adjacent to the one solar cell element 31 in the +Y direction as the second direction.

[0136] exist Figure 5 as well as Figure 6In the example of , five first wiring materials 32 as a plurality of first wiring materials 32 are in a state of electrically connecting the first solar cell element 31a and the second solar cell element 31b. Here, for example, each first wiring material 32 includes a portion bonded to the first solar cell element 31a and a portion bonded to the second solar cell element 31b. Five first wiring materials 32 as a plurality of first wiring materials 32 are in a state of electrically connecting the second solar cell element 31b and the third solar cell element 31c. Here, for example, each first wiring material 32 includes a portion bonded to the second solar cell element 31b and a portion bonded to the third solar cell element 31c. Five first wiring materials 32 as a plurality of first wiring materials 32 are in a state of electrically connecting the third solar cell element 31c and the fourth solar cell element 31d. Here, for example, each first wiring material 32 includes a portion bonded to the third solar cell element 31c and a portion bonded to the fourth solar cell element 31d. Five first wiring materials 32 as a plurality of first wiring materials 32 are in a state of electrically connecting the fourth solar cell element 31d and the fifth solar cell element 31e. Here, for example, each first wiring material 32 includes a portion bonded to the fourth solar cell element 31d and a portion bonded to the fifth solar cell element 31e. Five first wiring materials 32 as a plurality of first wiring materials 32 are in a state of electrically connecting the fifth solar cell element 31e and the sixth solar cell element 31f, respectively. Here, for example, each first wiring material 32 includes a portion bonded to the fifth solar cell element 31e and a portion bonded to the sixth solar cell element 31f.

[0137] The plurality of second wiring members 33 are in a state of electrically connecting two mutually adjacent solar cell strings 30 among the plurality of solar cell strings 30. Figure 5 In the example of FIG. 1 , the first second wiring material 33 electrically connects the first solar cell string 30a and the second solar cell string 30b. The second second wiring material 33 electrically connects the second solar cell string 30b and the third solar cell string 30c. The third second wiring material 33 electrically connects the third solar cell string 30c and the fourth solar cell string 30d.

[0138] The power generator 10 further includes, for example, two third wiring members 34. In order to output power from the solar cell section 3, the two third wiring members 34 are connected to the solar cell section 3, respectively. Figure 5In the example of , the first third wiring material 34 is electrically connected to the first solar cell string 30a located at the end in the -X direction. The second third wiring material 34 is electrically connected to the fourth solar cell string 30d located at the end in the +X direction. The two third wiring materials 34 each have a portion that is, for example, led to the outside of the power generation body 10. For example, the two third wiring materials 34 each exist in a state of being led to the outside of the power generation body 10 through the hole portion that penetrates the second protective member 2.

[0139] Here, for example, the number of solar cell strings 30 included in the solar cell section 3 is not limited to a plurality. The solar cell section 3 may include one solar cell string 30 or any number of two or more solar cell strings 30. In other words, the solar cell section 3 may include one or more solar cell strings 30. For example, in the case where the solar cell section 3 includes one solar cell string 30, the solar cell section 3 may not include the second wiring material 33. In addition, for example, as two or more solar cell elements 31, the solar cell string 30 may include two solar cell elements 31 or any number of three or more solar cell elements 31. Here, for example, a method in which the solar cell string 30 includes a first solar cell element 31a and a second solar cell element 31b as two solar cell elements 31 may be adopted. In other words, for example, a method in which the solar cell section 3 includes a first solar cell element 31a, a second solar cell element 31b, and a first wiring material 32 may be adopted.

[0140] <1-2-4. Sealing materials>

[0141] The sealing material 4 is, for example, in a state of covering the solar cell section 3. For example, the sealing material 4 is in a state of contacting the second surface 1s and the third surface 2f. In other words, the sealing material 4 is, for example, present in a state of filling the region between the first protective member 1 and the second protective member 2, and is in a state of covering the solar cell section 3 between the first protective member 1 and the second protective member 2. The sealing material 4 includes, for example, a sealing material (also referred to as a first sealing material) 41 located on the front surface 10f side and a sealing material (also referred to as a second sealing material) 42 located on the back surface 10b side. The first sealing material 41 is, for example, in a state of covering the entire surface of the solar cell section 3 on the first protective member 1 side. In other words, the first sealing material 41 is, for example, in a state of covering the solar cell section 3 between the first protective member 1 and the solar cell section 3. The second sealing material 42 is, for example, in a state of covering the entire surface of the solar cell section 3 on the second protective member 2 side. In other words, the second sealing material 42 is, for example, in a state of covering the solar cell section 3 between the second protective member 2 and the solar cell section 3. Therefore, the solar cell section 3 is, for example, in a state of being sandwiched and surrounded by the first sealing material 41 and the second sealing material 42. Thereby, for example, the posture of the solar cell section 3 can be maintained by the sealing material 4 .

[0142] In addition, the sealing material 4 is, for example, light-transmitting. Here, the sealing material 4 is, for example, light-transmitting to the wavelength of the above-mentioned specific range. For example, if at least the first sealing material 41 of the first sealing material 41 and the second sealing material 42 constituting the sealing material 4 is light-transmitting, the incident light from the front surface 10f side can reach the solar cell part 3. For example, the materials of the first sealing material 41 and the second sealing material 42 can be resins. More specifically, the material of the first sealing material 41 can be, for example, polyvinyl acetals such as ethylene-vinyl acetate copolymer (EVA: Ethylene-Vinyl Acetate), polyvinyl butyral (PVB: Poly-Vinyl Butyral), or polyolefin elastomer (POE: Polyolefin-Elastomer). Here, for example, if the material of the first sealing material 41 is relatively cheap EVA, the performance of protecting multiple solar cell elements 31 can be easily achieved.

[0143] As the material of the second sealing material 42, for example, polyvinyl acetal such as EVA or PVB or POE is applied, similarly to the first sealing material 41. Each of the first sealing material 41 and the second sealing material 42 may be composed of, for example, two or more materials.

[0144] In addition, the power generator 10 may also include a sealing portion (not shown) arranged along the annular portion opened to the external space in the region between the first protective member 1 and the second protective member 2. In this case, the sealing portion exists, for example, in a state of surrounding the outer peripheral portion of the region including the solar cell section 3 and the sealing material 4 in the region between the first protective member 1 and the second protective member 2. Here, the sealing portion exists, for example, in a manner of filling the region from the first protective member 1 to the second protective member 2. Here, for example, if the sealing portion has a lower moisture permeability than the sealing material 4, the sealing portion can seal the portion along the outer peripheral portion in the region between the first protective member 1 and the second protective member 2. Thus, the sealing portion can reduce the intrusion of moisture, etc. from the outside of the solar cell module 100 to the solar cell section 3. The material of the sealing portion is, for example, a butyl resin, a polyisocyanate resin, or an acrylic resin. The material of the sealing portion, for example, if it is a material with low moisture permeability, can include metals such as copper or solder or non-metals such as glass.

[0145] <1-2-5. Electrical connection between two adjacent solar cell elements>

[0146] The first wiring material 32 is, for example, in a state where the bus bar portion 311b as the first output portion located on the first element surface F1 of one solar cell element 31 is electrically connected to the second output portion 312b located on the second element surface F2 of another solar cell element 31 adjacent to the solar cell element 31 in the first direction or the second direction. Figure 1 as well as Figure 2 In the example of FIG. 1 , the outer edges of the plurality of first wiring members 32 bonded to the solar cell elements 31 are virtually depicted by thin double-dashed lines. Figure 1 , Figure 2 , Figures 5 to 7In the example of , the first wiring material 32 has an elongated shape along the -Y direction as the first direction. Here, the first wiring material 32 is, for example, in a state of being joined to the bus bar portion 311b of one solar cell element 31 and the second output portion 312b of another solar cell element 31 adjacent to the one solar cell element 31. Here, for example, there is a portion (also referred to as a first joining portion) 321 that joins the first wiring material 32 to the bus bar portion 311b between the first wiring material 32 and the bus bar portion 311b. Therefore, for example, the first wiring material 32 is in a state of being joined to the bus bar portion 311b of one solar cell element 31 via the first joining portion 321. In addition, for example, there is a portion (also referred to as a second joining portion) 322 that joins the first wiring material 32 to the second output portion 312b between the first wiring material 32 and the second output portion 312b. Therefore, for example, the first wiring material 32 is in a state of being joined to the second output portion 312b of another solar cell element 31 adjacent to the one solar cell element 31 via the second joining portion 322.

[0147] The first wiring material 32 is, for example, a metal body having a conductive line or strip shape. The shape of the cross section of the first wiring material 32 perpendicular to the long side direction may be, for example, a polygonal shape such as a rectangle, a triangle or a trapezoid, or a shape having a curve such as a circle or an ellipse, or a shape formed by combining a polygonal shape and a shape having a curve. The width W2 of the first wiring material 32 is, for example, set to 0.2 mm to 1.5 mm. The thickness of the first wiring material 32 is, for example, set to 0.1 mm to 1.5 mm. The width W2 of the first wiring material 32 is, for example, the length in the direction perpendicular to the long side direction of the first wiring material 32 (also referred to as the width direction) when looking down at the first element surface F1 of the solar cell element 31. The long side direction of the first wiring material 32 is, for example, the direction along the -Y direction as the first direction. The thickness of the first wiring material 32 is, for example, the length in the direction perpendicular to both the long side direction and the width direction of the first wiring material 32 (also referred to as the thickness direction). The material of the conductive metal body used for the first wiring material 32 is, for example, a good conductor such as copper.

[0148] The materials of the first joint portion 321 and the second joint portion 322 are, for example, low melting point alloys such as solder (tin solder) or low melting point single metals. For example, the entire surface of the first wiring material 32 is covered with solder. The first wiring material 32 is, for example, in a state of being electrically connected to the bus bar portion 311b and the second output portion 312b by welding. Here, for example, the solder between the first wiring material 32 and the bus bar portion 311b is in a state of constituting the first joint portion 321. In addition, for example, the solder between the first wiring material 32 and the second output portion 312b is in a state of constituting the second joint portion 322.

[0149] <<Joining of the first wiring member to the bus bar portion>>

[0150] In a first embodiment, for example, Figure 1 , Figure 2 as well as Figures 5 to 7 As shown, in the first solar cell element 31a, in the -Y direction as the first direction, the second end E2 of the bus bar portion 311b is located closer to the second solar cell element 31b than the first end E1 of the bus bar portion 311b. For example, in the second solar cell element 31b, in the -Y direction as the first direction, the second end E2 of the bus bar portion 311b is located closer to the third solar cell element 31c than the first end E1 of the bus bar portion 311b. For example, in the third solar cell element 31c, in the -Y direction as the first direction, the second end E2 of the bus bar portion 311b is located closer to the fourth solar cell element 31d than the first end E1 of the bus bar portion 311b. For example, in the fourth solar cell element 31d, in the -Y direction as the first direction, the second end E2 of the bus bar portion 311b is located closer to the fifth solar cell element 31e than the first end E1 of the bus bar portion 311b. For example, in the fifth solar cell element 31e, in the -Y direction as the first direction, the second end E2 of the bus bar portion 311b is located closer to the sixth solar cell element 31f than the first end E1 of the bus bar portion 311b.

[0151] In the state of the solar cell module 100, for example, Figure 1 as well as Figure 7 As shown, the first wiring material 32 is joined to the bus bar portion 311 b.

[0152] For example, Figure 1 , Figure 2 , Figure 6 as well as Figure 7As shown, the first wiring material 32 has a third end (also referred to as a third end) E3 and a fourth end (also referred to as a fourth end) E4 in the -Y direction as the first direction. In other words, the first wiring material 32 has a pair of third ends E3 and fourth ends E4 in the Y direction. Figure 1 , Figure 2 , Figure 6 as well as Figure 7 In the example, the third end E3 is the end of the first wiring material 32 in the -Y direction which is the first direction, and the fourth end E4 is the end of the first wiring material 32 in the +Y direction which is the second direction. In other words, for example, the first wiring material 32 has the third end E3 located on the -Y direction side which is the first direction on the first element surface F1, and the fourth end E4 located on the +Y direction side which is the second direction on the second element surface F2.

[0153] In the first embodiment, for example, in the first wiring material 32 that electrically connects the first solar cell element 31a and the second solar cell element 31b, the third end E3 is located in a region along the first solar cell element 31a, and the fourth end E4 is located in a region along the second solar cell element 31b. For example, in the first wiring material 32 that electrically connects the second solar cell element 31b and the third solar cell element 31c, the third end E3 is located in a region along the second solar cell element 31b, and the fourth end E4 is located in a region along the third solar cell element 31c. For example, in the first wiring material 32 that electrically connects the third solar cell element 31c and the fourth solar cell element 31d, the third end E3 is located in a region along the third solar cell element 31c, and the fourth end E4 is located in a region along the fourth solar cell element 31d. For example, in the first wiring material 32 that electrically connects the fourth solar cell element 31d and the fifth solar cell element 31e, the third end E3 is located in a region along the fourth solar cell element 31d, and the fourth end E4 is located in a region along the fifth solar cell element 31e. For example, in the first wiring member 32 electrically connecting the fifth solar cell element 31e and the sixth solar cell element 31f, the third end E3 is located in a region along the fifth solar cell element 31e and the fourth end E4 is located in a region along the sixth solar cell element 31f.

[0154] For example, Figure 1 as well as Figure 7As shown, the first wiring material 32 is in a state of being bonded to the bus bar portion 311b along the -Y direction as the first direction. More specifically, for example, in the first solar cell element 31a, the first wiring material 32 is in a state of being bonded to the bus bar portion 311b along the -Y direction as the first direction. For example, in the second solar cell element 31b, the first wiring material 32 is in a state of being bonded to the bus bar portion 311b along the -Y direction as the first direction. For example, in the third solar cell element 31c, the first wiring material 32 is in a state of being bonded to the bus bar portion 311b along the -Y direction as the first direction. For example, in the fourth solar cell element 31d, the first wiring material 32 is in a state of being bonded to the bus bar portion 311b along the -Y direction as the first direction. For example, in the fifth solar cell element 31e, the first wiring material 32 is in a state of being bonded to the bus bar portion 311b along the -Y direction as the first direction.

[0155] In addition, for example, Figure 2 As shown, the first wiring material 32 is in a state of being bonded to the second output portion 312b along the -Y direction as the first direction. More specifically, for example, in the second solar cell element 31b, the first wiring material 32 is in a state of being bonded to the second output portion 312b along the -Y direction as the first direction. For example, in the third solar cell element 31c, the first wiring material 32 is in a state of being bonded to the second output portion 312b along the -Y direction as the first direction. For example, in the fourth solar cell element 31d, the first wiring material 32 is in a state of being bonded to the second output portion 312b along the -Y direction as the first direction. For example, in the fifth solar cell element 31e, the first wiring material 32 is in a state of being bonded to the second output portion 312b along the -Y direction as the first direction. For example, in the sixth solar cell element 31f, the first wiring material 32 is in a state of being bonded to the second output portion 312b along the -Y direction as the first direction.

[0156] Moreover, in the first embodiment, for example, the first wiring material 32 includes a portion on the third end E3 side joined to the first end portion Ep1 of the bus bar portion 311 b. More specifically, for example, a portion of the first wiring material 32 constituting the third end E3 is joined to the first end portion Ep1 (for example, the seventh island portion Ip17).

[0157] <<Mechanism of Deterioration of Output Characteristics and Operations and Effects of First Embodiment>>

[0158] Here, for example, it is assumed that the solar cell module 100 is installed outdoors or the like for use. In this case, for example, during the day, the temperature of the solar cell module 100 rises due to the irradiation of the solar cell module 100 with sunlight and the power generation in the solar cell module 100 corresponding to the irradiation with sunlight. On the other hand, at night, the solar cell module 100 is not irradiated with sunlight, and the temperature of the solar cell module 100 decreases. Therefore, for example, in each part of the solar cell module 100, expansion due to a rise in temperature and contraction due to a drop in temperature are repeatedly generated. Here, due to the difference in thermal expansion coefficients corresponding to the materials constituting each part of the solar cell module 100, stress is repeatedly applied and relaxed in the solar cell module 100.

[0159] For example, it is assumed that the material of the first wiring material 32 is copper, the material of the first joint portion 321 that joins the first wiring material 32 to the bus bar portion 311b is solder, the material of the first electrode 311 is silver, and the material of the semiconductor substrate 310 is silicon. For example, the instantaneous linear expansion coefficient of copper is approximately 1.74×10 -5 [1 / K], the instantaneous linear expansion coefficient of solder is about 2.35×10 -5 [1 / K], the instantaneous linear expansion coefficient of silver is about 1.91×10 -5 [1 / K], the instantaneous linear expansion coefficient of silicon is about 0.26×10 -5 [1 / K]. K is Kelvin. Therefore, the first wiring material 32 , the first bonding portion 321 , and the first electrode 311 can expand and contract to a greater extent than the semiconductor substrate 310 in accordance with the rise and fall of the temperature.

[0160] Here, for example, the first electrode 311 is located on the first surface 310a of the semiconductor substrate 310, and the first wiring material 32 is joined to the bus bar portion 311b of the first electrode 311. In addition, in the first electrode 311, the bus bar portion 311b is connected to the finger portion 311f thinner than the bus bar portion 311b. Therefore, for example, when a force is applied to the bus bar portion 311b due to expansion and contraction in the longitudinal direction of the first wiring material 32, stress may be concentrated on the portion of the finger portion 311f connected to the bus bar portion 311b.

[0161] For example, when the first wiring material 32 expands, in the portion of the first wiring material 32 provided along the bus bar portion 311b, except for the portion near the third end E3, the expansion in the -Y direction, which is the first direction, and the expansion in the +Y direction, which is the second direction, cancel each other out between two or more portions joined to the bus bar portion 311b. On the other hand, the portion near the third end E3 of the first wiring material 32 provided along the bus bar portion 311b is easy to expand in the -Y direction, which is the first direction, and can apply a force in the -Y direction, which is the first direction, to the bus bar portion 311b. In this case, for example, when the portion constituting the third end E3 of the first wiring material 32 applies a force in the -Y direction, which is the first direction, to the first end portion Ep1 (for example, the seventh island portion Ip17), there is a possibility that stress concentration occurs in the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (for example, the seventh island portion Ip17).

[0162] For example, when the first wiring material 32 shrinks, the shrinkage in the +Y direction, which is the second direction, and the shrinkage in the -Y direction, which is the first direction, are offset between two or more portions joined to the bus bar portion 311b, except for the portion near the third end E3, among the portions of the first wiring material 32 disposed along the bus bar portion 311b. On the other hand, the portion near the third end E3 among the portions of the first wiring material 32 disposed along the bus bar portion 311b is likely to shrink in the +Y direction, which is the second direction, and a force can be applied to the bus bar portion 311b in the +Y direction, which is the second direction. In this case, for example, when the portion constituting the third end E3 of the first wiring material 32 applies a force in the +Y direction, which is the second direction, to the first end portion Ep1 (for example, the seventh island portion Ip17), there is a possibility that stress concentration occurs in the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (for example, the seventh island portion Ip17).

[0163] In contrast, in the solar cell module 100 according to the first embodiment, the width of the first portion (first connection portion) P1 of the first finger portion 311f1 is larger than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. Therefore, even if the portion constituting the third end E3 of the first wiring member 32 applies a force to the first end portion Ep1 (for example, the seventh island portion Ip17) in either the -Y direction as the first direction or the +Y direction as the second direction, it is considered that the stress applied to the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (for example, the seventh island portion Ip17) may be reduced.

[0164] Furthermore, in a solar cell module 100 installed outdoors, for example, the bonding strength between the bus bar portion 311 b and the semiconductor substrate 310 may be reduced due to a combination of moisture stress caused by humidity and / or rainfall and temperature stress caused by temperature.

[0165] Here, for example, it is assumed that the first wiring member 32 that connects the bus bar portion 311b of the first solar cell element 31 and the second output portion 312b of the second solar cell element 31 adjacent to the first solar cell element 31 shrinks. In this case, the displacement of the bus bar portion 311b accompanying the shrinkage of the first wiring member 32 increases from the second end E2 of the bus bar portion 311b of the first solar cell element 31 close to the second solar cell element 31 to the first end E1 close to the third end E3 that is the end (free end) of the first wiring member 32. In this case, it is considered that the stress generated in the bus bar portion 311b is proportional to the magnitude of the displacement of the bus bar portion 311b. Therefore, it is considered that the stress generated in the bus bar portion 311b is particularly large in the first end portion Ep1 (for example, the seventh island portion Ip17) located on the first end E1 side close to the third end E3 that is the end (free end) of the first wiring member 32 in the bus bar portion 311b.

[0166] On the contrary, here, for example, it is assumed that the first wiring member 32 that connects the bus bar portion 311b of the first solar cell element 31 and the second output portion 312b of the second solar cell element 31 adjacent to the first solar cell element 31 expands. In this case, the displacement of the bus bar portion 311b accompanying the expansion of the first wiring member 32 increases from the second end E2 of the bus bar portion 311b of the first solar cell element 31 close to the second solar cell element 31 to the first end E1 close to the third end E3 as the end (free end) of the first wiring member 32. In this case, it is considered that the stress generated in the bus bar portion 311b is proportional to the magnitude of the displacement of the bus bar portion 311b. Therefore, it is considered that the stress generated in the bus bar portion 311b is particularly large in the first end portion Ep1 (for example, the seventh island portion Ip17) located on the first end E1 side close to the third end E3 as the end (free end) of the first wiring member 32 in the bus bar portion 311b.

[0167] In these cases, if the adhesive strength between the bus bar portion 311b and the semiconductor substrate 310 is reduced due to the hygrothermal stress, the bus bar portion 311b may partially peel off from the semiconductor substrate 310 starting from the first end E1 side at the first end portion Ep1 (for example, the seventh island portion Ip17) of the bus bar portion 311b of the first solar cell element 31. In other words, peeling may occur between the semiconductor substrate 310 and the first electrode 311 starting from the first end E1 side.

[0168] Thereafter, in the solar cell module 100, the temperature rises in accordance with the irradiation of sunlight and power generation during the day and the temperature drops at night are repeated, and the thermal expansion and thermal contraction of the first wiring member 32 are repeated. As a result, the bus bar portion 311b can be partially peeled off from the semiconductor substrate 310 starting from the first end E1 side.

[0169] Here, the portion of the bus bar portion 311b that is peeled off from the semiconductor substrate 310 is displaced in a manner corresponding to the displacement caused by the thermal expansion and thermal contraction of the first wiring material 32. At this time, since there is no constraint of the semiconductor substrate 310 in the portion of the bus bar portion 311b that is peeled off from the semiconductor substrate 310 and the first wiring material 32 bonded to the portion, a larger displacement is generated than in the case where the bus bar portion 311b is not peeled off from the semiconductor substrate 310. This large displacement generated in the bus bar portion 311b generates a greater stress in the first portion P1 of the first finger portion 311f1 to which the bus bar portion 311b is connected than in the case where the bus bar portion 311b is not peeled off from the semiconductor substrate 310.

[0170] As a result of the above, for example, the first end portion Ep1 located on the first end E1 side of the bus bar portion 311b of the first solar cell element 31 is more likely to generate greater stress in the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (for example, the first island portion Ip11) after the local peeling from the semiconductor substrate 310 starting from the first end E1 side occurs, compared with before the local peeling from the semiconductor substrate 310 starting from the first end E1 side occurs.

[0171] If such a greater stress is repeatedly generated in the first portion P1 of the first finger 311f1, cracks may be generated on the surface of the first portion P1. The cracks may develop at a speed corresponding to the stress generated in the first portion P1.

[0172] In contrast, in the first embodiment, the width of the first portion (first connection portion) P1 is increased. More specifically, in the first embodiment, the width of the first portion (first connection portion) P1 is made larger than the width of the third portion P3. As a result, the time until the first portion P1 of the first finger portion 311f1 is disconnected can be extended. As a result, the speed of deterioration of the output characteristics caused by the increase and decrease of the temperature in the solar cell module 100 can be reduced. In other words, the degree of deterioration of the output characteristics of the solar cell module 100 when the same stress is applied can be reduced.

[0173] As described above, in the first embodiment, the reliability of the solar cell element 31 and the solar cell module 100 can be improved.

[0174] Here, improvement of the degree of degradation of output characteristics with respect to moist heat stress in the solar cell module 100 according to the first embodiment will be described with reference to specific examples.

[0175] Here, as three specific examples of the solar cell module 100 involved in the first embodiment, a solar cell module of the first specific example (also referred to as the first specific example), a solar cell module of the second specific example (also referred to as the second specific example), and a solar cell module of the third specific example (also referred to as the third specific example) were manufactured. In the first specific example, the width of the first portion (first connection portion) P1 of each of all the first finger portions 311f1 connected to the seventh island portion Ip17 as the first end portion Ep1 was set to 60μm. In the second specific example, the width of the first portion (first connection portion) P1 of each of all the first finger portions 311f1 connected to the seventh island portion Ip17 as the first end portion Ep1 was set to 120μm. In the third specific example, the width of the first portion (first connection portion) P1 of each of all the first finger portions 311f1 connected to the seventh island portion Ip17 as the first end portion Ep1 was set to 180μm. In the first specific example, the second specific example, and the third specific example, the length of the first portion (first connection portion) P1 in the +X direction, which is the third direction, is set to 1.5 mm, and the width of all the finger portions 311f except the first portion (first connection portion) P1 is set to 32 μm. In addition, the first specific example, the second specific example, and the third specific example have the same structure except for the width of the first portion (first connection portion) P1.

[0176] In addition, as a reference example of the solar cell module, a solar cell module of the first reference example (also referred to as the first reference example) was manufactured. The first reference example is based on the first specific example, the second specific example, and the third specific example, and is a solar cell module having a structure in which the width of each first portion (first connection portion) P1 of all first finger portions 311f1 connected to the seventh island portion Ip17 as the first end portion Ep1 is changed to 32μm. That is, in the first reference example, the width of all finger portions 311f is set to 32μm.

[0177] As a composite stress test for each solar cell module, a high temperature and high humidity test and a temperature cycle test were performed in sequence. In the high temperature and high humidity test, the solar cell module was placed in an environment with a temperature of 85 degrees Celsius (85°C) and a humidity of 85% for 1,000 hours. In the temperature cycle test, the following test was performed: 100 cycles of periodically changing the temperature of the solar cell module between 85°C and -40°C over a period of 6 hours were used as one set of treatments, and two sets of treatments were performed on the solar cell module.

[0178] Then, the fill factors (FF: Fill Factor) before and after the combined stress test for applying the moisture-heat stress were measured for the solar cell modules of the first specific example, the second specific example, the third specific example, and the first reference example.

[0179] Here, based on the FF (curve factor) measured before and after the composite stress test, the change rate of FF is calculated for the first specific example, the second specific example, the third specific example, and the first reference example. Here, for each of the first specific example, the second specific example, the third specific example, and the first reference example, the change rate of FF (in percentage (%)) is calculated according to formula (1). In addition, for any of the first specific example, the second specific example, the third specific example, and the first reference example, the FF after the composite stress test is a smaller value than the FF before the composite stress test, and the change rate of FF is a negative value.

[0180] FF change rate [%] = {(FF after the combined stress test - FF before the combined stress test) / FF before the combined stress test} × 100 ... (1).

[0181] Furthermore, the change rate of FF (curve factor) with respect to the first reference example is set as the first reference change rate, the change rate of FF (curve factor) with respect to the first specific example is set as the first change rate, the change rate of FF (curve factor) with respect to the second specific example is set as the second change rate, and the change rate of FF (curve factor) with respect to the third specific example is set as the third change rate.

[0182] Table 1 shows the relative change rates of the first specific example, the second specific example, and the third specific example based on the first reference change rate.

[0183] In Table 1, 0% is shown as a reference value for the first reference example. In addition, as the relative change rate of FF (curve factor) for the first specific example (also referred to as the first relative change rate), a value obtained by subtracting the first reference change rate from the first change rate, that is, +0.4%, is shown. In addition, as the relative change rate of FF (curve factor) for the second specific example (also referred to as the second relative change rate), a value obtained by subtracting the first reference change rate from the second change rate, that is, +1.9%, is shown. In addition, as the relative change rate of FF (curve factor) for the third specific example (also referred to as the third relative change rate), a value obtained by subtracting the first reference change rate from the third change rate, that is, +2.7%, is shown. That is, the first relative change rate, the second relative change rate, and the third relative change rate are calculated according to Formula (2), Formula (3), and Formula (4), respectively.

[0184] First relative change rate = first change rate - first reference change rate... (2)

[0185] Second relative change rate = second change rate - first reference change rate... (3)

[0186] The third relative change rate = the third change rate - the first reference change rate ... (4).

[0187] In addition, Table 1 also shows the width of the first portion (first connecting portion) P1 of each of the first reference example, the first specific example, the second specific example, and the third specific example.

[0188] [Table 1]

[0189]

[0190] As shown in Table 1, in the first specific example, the second specific example, and the third specific example in which the width of the first portion (first connection portion) P1 is increased to 60 μm, 120 μm, and 180 μm compared to the first reference example in which the width of the first portion (first connection portion) P1 is set to 32 μm, the negative values ​​of the first change rate, the second change rate, and the third change rate are closer to zero (0) than the first reference change rate which is a negative value, and it can be confirmed that the rate of reduction of FF (curve factor) due to the combined cycle test is reduced. More specifically, in the first specific example in which the width of the first portion (first connection portion) P1 is increased to 60 μm compared to the first reference example in which the width of the first portion (first connection portion) P1 is set to 32 μm, it can be confirmed that the negative value of the first change rate is closer to zero (0) than the first reference change rate which is a negative value, and the rate of reduction of FF (curve factor) due to the combined cycle test is reduced. In the second specific example in which the width of the first portion (first connection portion) P1 is increased to 120 μm compared to the first reference example in which the width of the first portion (first connection portion) P1 is set to 32 μm, the negative value of the second change rate is closer to zero (0) than the first reference change rate which is a negative value, and it can be confirmed that the reduction rate of FF (curve factor) caused by the combined cycle test is reduced. In the third specific example in which the width of the first portion (first connection portion) P1 is increased to 180 μm compared to the first reference example in which the width of the first portion (first connection portion) P1 is set to 32 μm, it can be confirmed that the negative value of the third change rate is closer to zero (0) than the first reference change rate which is a negative value, and the reduction rate of FF (curve factor) caused by the combined cycle test is reduced. That is, it was confirmed that, as in the first embodiment, by increasing the width of the first portion (first connection portion) P1, the degree of deterioration of the output characteristics of the solar cell module 100 when the same stress is applied is reduced. In other words, it is inferred that, by increasing the width of the first portion (first connection portion) P1 as in the first embodiment, durability is improved in the solar cell element 31 and the solar cell module 100 , thereby improving reliability.

[0191] In addition, as shown in Table 1, the greater the width of the first portion (first connection portion) P1, the greater the positive value of the relative change rate of FF, the closer the change rate of FF as a negative value is to zero (0), and the smaller the absolute value of the change rate of FF becomes, so it can be confirmed that the reduction rate of FF (curve factor) caused by the combined cycle test becomes smaller. That is, in the first embodiment, it is confirmed that there is a tendency that the greater the width of the first portion (first connection portion) P1, the smaller the degree of deterioration of the output characteristics of the solar cell module 100 when the same stress is applied.

[0192] However, from another point of view, in the solar cell module 100 according to the first embodiment, the width of the third portion (second connection portion) P3 of the second finger 311f2 is smaller than the width of the first portion (first connection portion) P1 of the first finger 311f1. In other words, the width of a portion of the fingers 311f, that is, the first portion (first connection portion) P1 of the first finger 311f1, is selectively increased. Therefore, for example, compared with a configuration in which all the fingers 311f have the same and large width or a configuration in which all the fingers 311f have the same structure as the first finger 311f1, the amount of sunlight incident on the semiconductor substrate 310 that is blocked by the plurality of second fingers 311f2 can be reduced. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved. Therefore, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved. Furthermore, the material required to form the plurality of fingers 311f can also be reduced.

[0193] Here, for example, consider a case where the first wiring material 32 is joined to the bus bar portion 311b in a state where the long side direction of the first wiring material 32 is slightly inclined with respect to the -Y direction as the first direction. In this case, for example, the position of the first wiring material 32 joined to the first end portion Ep1 (for example, the seventh island portion Ip17) of the bus bar portion 311b is likely to be deviated from the center of the width direction of the first end portion Ep1 (for example, the seventh island portion Ip17). The width direction may be a direction along the +X direction as the third direction. Therefore, for example, there is a case where the portion near the third end E3 of the first wiring material 32 is close to the first finger portion 311f1, and the force applied to the seventh island portion Ip17 from the portion near the third end E3 of the first wiring material 32 is likely to be applied to the first portion P1 in accordance with the expansion and contraction of the portion near the third end E3 of the first wiring material 32. Even in this case, for example, if the width of the first portion (first connection portion) P1 of the first finger portion 311f1 is larger than the width of the third portion (second connection portion) P3 of the second finger portion 311f2, the stress applied to the first portion P1 may be reduced.

[0194] Furthermore, for example, even if the first end portion Ep1 of the bus bar portion 311b is partially peeled off from the semiconductor substrate 310 due to the moist heat stress, if the width of the first portion (first connection portion) P1 is large, the time until the first portion (first connection portion) P1 is disconnected may be prolonged. Here, for example, if the width of the first portion (first connection portion) P1 is larger than the width of the third portion P3, the width of the first portion (first connection portion) P1 may be increased.

[0195] Thus, among the plurality of first finger portions 311f1, it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the first end portion Ep1.

[0196] However, when the solar cell element 31 according to the first embodiment is used to manufacture the solar cell module 100, the portion constituting the third end E3 of the first wiring member 32 can be joined to the first end portion Ep1 (for example, the seventh island portion Ip17). In this case, as described above, in the solar cell module 100, for example, when the portion constituting the third end E3 of the first wiring member 32 applies a force to the first end portion Ep1 (for example, the seventh island portion Ip17) in either the -Y direction as the first direction or the +Y direction as the second direction, stress concentration may occur in the first portion P1 of the first finger 311f1 connected to the first end portion Ep1 (for example, the seventh island portion Ip17).

[0197] In contrast, in the state of the solar cell element 31 according to the first embodiment before manufacturing the solar cell module 100, the width of the first portion (first connection portion) P1 of the first finger portion 311f1 connected to the first end portion Ep1 (for example, the seventh island portion Ip17) in the bus bar portion 311b is greater than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. Furthermore, for example, when the solar cell module 100 is manufactured using the solar cell element 31 according to the first embodiment, the portion constituting the third end E3 of the first wiring member 32 can be joined to the first end portion Ep1 (for example, the seventh island portion Ip17). Therefore, it is considered that: for example, no matter which direction of the -Y direction as the first direction and the +Y direction as the second direction is applied to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) by the portion constituting the third end E3 in the first wiring material 32, the stress applied to the first portion P1 of the first finger-shaped portion 311f1 connected to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) is likely to be reduced.

[0198] Furthermore, for example, even if the first end portion Ep1 of the bus bar portion 311b is partially peeled off from the semiconductor substrate 310 due to the moist heat stress, if the width of the first portion (first connection portion) P1 is large, the time until the first portion (first connection portion) P1 is disconnected may be prolonged. Here, for example, if the width of the first portion (first connection portion) P1 is larger than the width of the third portion P3, the width of the first portion (first connection portion) P1 may be increased.

[0199] Thus, among the plurality of first finger portions 311 f 1 , it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the first end portion Ep1 (for example, the seventh island portion Ip17 ).

[0200] As a result, in the solar cell element 31 and the solar cell module 100 , the reliability can be improved by improving the durability.

[0201] Furthermore, from another point of view, in the state of the solar cell element 31 according to the first embodiment before the solar cell module 100 is manufactured, the width of the third portion (second connection portion) P3 of the second finger 311f2 is smaller than the width of the first portion (first connection portion) P1 of the first finger 311f1. In other words, the width of a part of the fingers 311f among the plurality of fingers 311f, that is, the first portion (first connection portion) P1 of the first finger 311f1 is selectively increased. Therefore, when the solar cell module 100 is manufactured using the solar cell element 31 according to the first embodiment, for example, compared with a method in which all the fingers 311f have the same and large width or a method in which all the fingers 311f have the same structure as the first finger 311f1, the amount of sunlight incident on the semiconductor substrate 310 that is blocked by the plurality of second fingers 311f2 can be reduced. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved. Therefore, it is possible to improve the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100. In addition, it is also possible to reduce the material required to form the plurality of finger portions 311f.

[0202] In other words, assuming that the solar cell element 31 according to the first embodiment is used to manufacture the solar cell module 100, the solar cell element 31 according to the first embodiment has a structure suitable for improving the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100. That is, according to the solar cell element 31 according to the first embodiment, it is possible to improve the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100. In addition, it is also possible to reduce the material required for forming the plurality of finger-shaped portions 311f.

[0203] Here, for example, in the third finger portion 311f3 connected to the connection portion CP1, the width of the fifth portion P5 may be larger than the width of the sixth portion P6, and the length L1 from the fifth end E5 to the sixth end E6 in the +X direction as the third direction may be larger than the width W2 of the first wiring member 32. Thus, for example, even when the width W2 of the first wiring member 32 is larger than the width of the connection portion Cp1, the first wiring member 32 is bonded to the fifth portion P5 in the third finger portion 311f3, and the bonding of the first wiring member 32 to the sixth portion P6 thinner than the fifth portion P5 can be reduced. Therefore, for example, in the solar cell module 100, even if the first wiring member 32 expands and contracts according to the rise and fall of the temperature, the force applied by the first wiring member 32 to the sixth portion (third thin line portion) P6 may be reduced.

[0204] As a result, the occurrence of disconnection in the third finger portion 311f3 can be reduced.

[0205] That is, the occurrence of disconnection in the finger portion 311f can be reduced. Therefore, in the solar cell element 31 and the solar cell module 100, the reliability can be improved by improving the durability.

[0206] Here, for example, if the width W1 of the island portion Ip1 is larger than the width W2 of the first wiring material 32, the first wiring material 32 can be joined at a position deviated from the center of the island portion Ip1 in the direction (also referred to as the width direction) along the +X direction which is the third direction of the island portion Ip1. Therefore, for example, when the first wiring material 32 is joined to the bus bar portion 311b, it is possible to allow the first wiring material 32 to deviate from the bus bar portion 311b in the direction along the +X direction which is the third direction, and to allow the long side direction of the first wiring material 32 to be slightly inclined with respect to the -Y direction which is the first direction.

[0207] <1-3. Manufacturing of solar cell elements>

[0208] Reference Figure 3 as well as Figures 8 to 12 An example of a method for manufacturing the solar cell element 31 is described. For example, the solar cell element 31 can be manufactured by preparing a semiconductor substrate 310, forming a texture structure, forming a second type region 310s, forming a passivation film 313, forming an anti-reflection film 314, forming a protective film 315, and forming an electrode in the order described below.

[0209] <<Preparation of semiconductor substrate>>

[0210] For example, Figure 8As shown, a semiconductor substrate 310 is prepared. The semiconductor substrate 310 has a first surface 310a and a second surface 310b on the opposite side of the first surface 310a. The semiconductor substrate 310 can be formed, for example, using an existing Czochralski (CZ) method or a casting method. Here, an example of using a p-type polycrystalline silicon ingot as a first conductivity type produced by a casting method is described. The semiconductor substrate 310 is produced by thinning the ingot to a desired thickness of, for example, less than 250 μm. Here, for example, by applying a slight amount of etching to the surface of the semiconductor substrate 310 with an aqueous solution of sodium hydroxide, potassium hydroxide, or nitric acid, it is possible to remove a mechanically damaged layer and a contaminated layer in the cut surface of the semiconductor substrate 310.

[0211] <<Formation of Texture Structure>>

[0212] For example, Fig. 9 As shown, a structure having a fine concavo-convex shape (also referred to as a texture structure) is formed on the first surface 310a of the semiconductor substrate 310. The texture structure can be formed by wet or dry etching. Wet etching can be performed, for example, using an alkaline aqueous solution such as sodium hydroxide or an acidic aqueous solution such as fluorine nitric acid. Dry etching can be performed, for example, using a reactive ion etching (RIE) method.

[0213] <<Formation of Second Conductivity Type Region>>

[0214] For example, Fig.10 As shown, a region of n-type semiconductor of the second conductivity type, i.e., a second type region 310s, is formed on the first surface 310a having a texture structure in the semiconductor substrate 310. More specifically, a region of n-type semiconductor of the second conductivity type, i.e., a second type region 310s, is formed on the surface layer of the first surface 310a having a texture structure in the semiconductor substrate 310. The second type region 310s can be formed, for example, by using a coating thermal diffusion method or a gas phase thermal diffusion method. In the coating thermal diffusion method, for example, phosphorus pentoxide (P pentoxide) in a paste form is applied. 2 O 5 ) is applied to the surface of the semiconductor substrate 310 to thermally diffuse phosphorus. In the gas phase thermal diffusion method, for example, phosphorus oxychloride (POCl 3) is used as a diffusion source. Here, for example, in the case where the second type region 310s is also formed on the second surface 310b side of the semiconductor substrate 310, the second type region 310s formed on the second surface 310b side is removed by etching using an aqueous solution of fluorine nitric acid. Thereafter, for example, when the second type region 310s is formed, the phosphorus glass attached to the first surface 310a side of the semiconductor substrate 310 is removed by etching. Here, for example, a diffusion mask may be formed in advance on the second surface 310b side of the semiconductor substrate 310, the second type region 310s may be formed by a vapor phase thermal diffusion method or the like, and then the diffusion mask may be removed.

[0215] <<Formation of Passivation Film>>

[0216] For example, a passivation film 313 is formed at least on the second surface 310b of the semiconductor substrate 310. Fig.11 As shown, a passivation film 313 is formed on the second surface 310b and the first surface 310a of the semiconductor substrate 310. The passivation film 313 can be composed of a film mainly containing aluminum oxide, for example. Here, the passivation film 313 can be formed by, for example, an atomic layer deposition (ALD) method. According to the ALD method, for example, the passivation film 313 can be formed around the entire periphery including the end surface of the semiconductor substrate 310. In the formation process of the passivation film 313 based on the ALD method, first, the semiconductor substrate 310 formed to the second type region 310s is placed in the chamber of the film forming device. Then, while the semiconductor substrate 310 is heated from 100 degrees Celsius (100°C) to a temperature range of about 250 degrees Celsius (250°C), the following steps A to D are repeated multiple times, thereby forming a passivation film 313 mainly containing aluminum oxide. Thus, a passivation film 313 having a desired thickness is formed.

[0217] [Process A] Aluminum raw materials such as trimethylaluminum (TMA) for forming aluminum oxide are supplied to the semiconductor substrate 310 together with a carrier gas such as argon (Ar) gas or nitrogen gas. As a result, the aluminum raw material is adsorbed around the entire periphery of the semiconductor substrate 310. The time for supplying TMA is set to, for example, about 15 milliseconds to 3000 milliseconds. Here, at the beginning of process A, for example, the surface of the semiconductor substrate 310 is terminated with a hydroxyl group (OH group). In this case, the surface of the semiconductor substrate 310 has a Si-OH structure. This structure can be formed, for example, by treating the semiconductor substrate 310 with dilute hydrofluoric acid and washing it with pure water in the order described below.

[0218] [Step B] The chamber of the film forming apparatus is purged using nitrogen gas. Here, the aluminum raw material in the chamber is removed, and the aluminum raw material other than the components chemically adsorbed at the atomic layer level in the aluminum raw material physically adsorbed and chemically adsorbed on the semiconductor substrate 310 is removed. Here, the time for purging the chamber with nitrogen gas is set to, for example, about 1 second to several tens of seconds.

[0219] [Step C] An oxidant such as water or ozone gas is supplied into the chamber of the film forming device. As a result, the alkyl groups contained in TMA are removed and replaced by OH groups. As a result, an atomic layer of aluminum oxide is formed on the semiconductor substrate 310. Here, the time for supplying the oxidant into the chamber is set to, for example, about 750 milliseconds to 1100 milliseconds. Here, for example, hydrogen can be supplied into the chamber together with the oxidant so that the aluminum oxide contains hydrogen atoms.

[0220] [Step D] Purging the chamber of the film forming device with nitrogen gas. Thus, the oxidant in the chamber is removed. Here, for example, the oxidant that does not contribute to the reaction when aluminum oxide is formed at the atomic layer level on the semiconductor substrate 310 is removed. Here, the time for purging the chamber with nitrogen gas is set to about 1 second to several tens of seconds, for example.

[0221] <<Formation of anti-reflection film>>

[0222] For example, Fig.11 As shown, an anti-reflection film 314 is formed on the passivation film 313. The anti-reflection film 314 can be composed of, for example, a silicon nitride film. Here, the anti-reflection film 314 can be formed, for example, using a plasma CVD (plasma-enhanced chemical vapor deposition: PECVD) method or a sputtering method. When the PECVD method is used, the semiconductor substrate 310 is heated in advance to a temperature higher than the temperature during the film formation of the anti-reflection film 314. Thereafter, the reaction pressure is set to about 50 Pa (Pascal) to 200 Pa, and the mixed gas of silane and ammonia diluted with nitrogen is plasma-formed by glow discharge decomposition and deposited on the heated semiconductor substrate 310. Thus, an anti-reflection film 314 is formed on the semiconductor substrate 310. Here, the film formation temperature is set to about 350°C to 650°C, and the pre-heating temperature of the semiconductor substrate 310 is set to about 50°C higher than the film formation temperature. As the frequency of the high-frequency power source required for glow discharge, a frequency of about 10 kilohertz (kHz) to 500 kHz or a frequency of MHz band such as 13.5 megahertz (MHz) is adopted. The flow rate of the gas is appropriately determined according to the size of the reaction chamber, etc. For example, the flow rate of the gas is set to a range of about 150 ml per minute to 6000 ml per minute. Here, the value (B / A) obtained by dividing the flow rate B of the ammonia gas by the flow rate A of the silane gas is set to a range of 0.5 to 1.5.

[0223] <<Formation of protective film>>

[0224] For example, Fig.12 As shown, a protective film 315 having a desired pattern is formed on the passivation film 313 at least on the second surface 310b side of the semiconductor substrate 310. The desired pattern includes a plurality of through holes, etc. The protective film 315 can be formed, for example, by a wet or dry process. The wet process, for example, uses a process such as coating with a solution. The dry process, for example, uses a process such as PECVD or sputtering. For example, in the case of a wet process using coating with a solution, after a solution is applied to the passivation film 313 in a manner having a desired pattern, the solution is dried to form the protective film 315. The desired pattern includes a plurality of through holes. Here, as a solution, for example, an insulating paste is used. As an insulating paste, for example, an insulating paste including a siloxane resin, an organic solvent, and a plurality of fillers, which are raw materials for the protective film 315, is used. Siloxane resin is a siloxane compound having a siloxane bond (Si-O-Si bond). For example, the siloxane resin is a low molecular weight resin having a molecular weight of 15,000 or less, which is produced by hydrolyzing and polycondensing alkoxysilane or silazane. The solution can be applied, for example, using a screen printing method. The applied solution can be dried, for example, using a hot plate or a drying oven.

[0225] <<Electrode formation>>

[0226] For example, Figure 3 As shown, a first electrode 311 and a second electrode 312 are formed.

[0227] Here, for example, a material for forming the first electrode 311 (also referred to as a first electrode material) is arranged in a desired pattern on the first surface 310a side of the semiconductor substrate 310. More specifically, for example, the first electrode material is arranged in a desired pattern on the anti-reflection film 314 formed on the first surface 310a. Then, the first electrode 311 is formed by heating the first electrode material. For example, when the main component of the material of the first electrode 311 is silver, a silver paste is used as the first electrode material. In this case, the arrangement of the first electrode material is performed, for example, by applying a silver paste. The application of the silver paste can be achieved, for example, by a screen printing method. Here, the solvent in the silver paste can be evaporated by drying the applied silver paste at a given temperature. Thereafter, for example, in a firing furnace, the silver paste is fired under the conditions of a maximum temperature of about 600°C to 850°C and a heating time of about tens of seconds to tens of minutes. Thus, the first electrode 311 can be formed.

[0228] In addition, here, for example, a material for forming the second electrode 312 (also referred to as a second electrode material) is arranged in a desired pattern on the second surface 310b side of the semiconductor substrate 310. More specifically, for example, a material for forming the second electrode 312 (also referred to as a second electrode material) is arranged on the protective film 315, in a plurality of through holes of the protective film 315, and in a plurality of hole portions of the protective film 315. Then, the second electrode 312 is formed by heating the second electrode material. For example, when the main component of the material of the second output portion 312b is silver and the main component of the material of the second collector portion 312c is aluminum, silver paste and aluminum paste are used as the second electrode material. In this case, the arrangement of the second electrode material is performed, for example, by applying a silver paste and applying an aluminum paste. The application of the silver paste and the application of the aluminum paste can be achieved, for example, by a screen printing method, etc. Here, for example, a silver paste is applied in a desired pattern on the second surface 310b side of the semiconductor substrate 310. More specifically, for example, silver paste is applied on the passivation film 313 exposed from the multiple holes of the protective film 315. In addition, for example, on the second surface 310b side of the semiconductor substrate 310, aluminum paste is applied in a desired pattern that contacts a portion of the applied silver paste. More specifically, for example, aluminum paste is applied on the protective film 315 on the second surface 310b, in the multiple through holes of the protective film 315, and on a portion of the applied silver paste. Here, the silver paste and the solvent in the silver paste can be evaporated by drying the applied silver paste and the silver paste at a given temperature. Thereafter, for example, in a firing furnace, the silver paste and the aluminum paste are fired under the conditions of a maximum temperature of about 600°C to 850°C and a heating time of about tens of seconds to tens of minutes. In this way, the second electrode 312 can be formed. When the aluminum paste is fired, the aluminum paste disposed in the plurality of through holes of the protective film 315 is fired through (also referred to as burn-through) the passivation film 313, and a BSF region 310t is formed on the surface of the first type region 310f. Here, for example, the second output portion 312b and the second collector portion 312c may be formed simultaneously, the second collector portion 312c may be formed after the second output portion 312b is formed, or the second output portion 312b may be formed after the second collector portion 312c is formed.

[0229] Here, for example, the first electrode 311 and the second electrode 312 may be formed by applying the metal pastes and then firing them simultaneously.

[0230] <1-4. Manufacturing of solar cell modules>

[0231] Reference Fig.13 as well as Fig.14 An example of a method for manufacturing the solar cell module 100 according to the first embodiment will be described.

[0232] First, prepare the first protective member 1. Here, for example, as the first protective member 1, a member having a rectangular front and back surface and a light-transmitting flat plate or sheet shape is prepared.

[0233] Next, for example, Fig.13 as well as Fig.14 As shown, the laminate 10s is formed by laminating the first protective member 1, the first sheet 41s, the solar cell section 3, the second sheet 42s, and the second protective member 2 in the order described. In the laminate 10s, for example, the portion of the third wiring material 34 connected to the solar cell section 3 for connecting to the terminal box J1 and the like outside the power generation body 10 is arranged in a state of being led out to the outside of the laminate 10s.

[0234] The first sheet 41s is a resin sheet that serves as the material of the first sealing material 41. The material of the resin sheet is, for example, EVA. In the laminate 10s, the first sheet 41s is located between the first protective member 1 and the solar cell section 3. In other words, in the laminate 10s, the first sheet 41s is located on the first protective member 1, and the solar cell section 3 is located on the first sheet 41s. The first sheet 41s has a rectangular shape as an example of a rectangular shape when viewed from above. The first sheet 41s can be composed of one sheet or two or more sheets.

[0235] The second sheet material 42s is a resin sheet material that becomes the material of the second sealing material 42. The material of the resin sheet material is, for example, EVA. The second sheet material 42s may also include a pigment. In the laminate 10s, the second sheet material 42s is located between the solar cell portion 3 and the second protective member 2. In other words, in the laminate 10s, the second sheet material 42s is located above the solar cell portion 3, and the second protective member 2 is located above the second sheet material 42s. The second sheet material 42s has a rectangular shape as an example of a rectangular shape when viewed from above. The second sheet material 42s may be composed of one sheet material or may be composed of two or more sheets.

[0236] Next, for example, a lamination process is performed on the stack 10s. In the lamination process, for example, a lamination device (also called a laminator) is used to integrate the stack 10s. For example, in the laminator, the stack 10s is placed on a heater plate in the chamber, the air pressure in the chamber is reduced from 50Pa (Pascal) to about 150Pa, and the stack 10s is heated from 100°C to about 200°C. Here, the first sheet 41s and the second sheet 42s are in a state where they can flow to a certain extent by heating. In this state, in the chamber, the stack 10s can be integrated by pressing the stack 10s in the +Z direction using a pressing body such as a diaphragm sheet. Next, a cross-linking process is performed on the stack 10s. In the cross-linking process, for example, a cross-linking furnace is used to heat the integrated stack 10s from 110°C to about 210°C. This treatment can impart rubber elasticity to the first sheet 41s and the second sheet 42s, and improve the heat resistance of the first sheet 41s and the second sheet 42s.

[0237] In this way, the power generator 10 can be manufactured.

[0238] After the lamination process, the terminal box J1 and the frame 6 may be appropriately mounted on the power generation body 10. In this case, for example, a portion of the third wiring material 34 drawn from the solar cell section 3 to the outside of the power generation body 10 is appropriately connected to the terminal in the terminal box J1. In addition, when the frame 6 is mounted along the outer periphery of the power generation body 10, for example, a sealing material with low moisture permeability such as a butyl resin is filled between the outer periphery of the power generation body 10 and the frame 6. In this way, the solar cell module 100 according to the first embodiment can be manufactured.

[0239] <1-5. Summary of the first embodiment>

[0240] In the solar cell element 31 according to the first embodiment, the width of the first portion (first connection portion) P1 of the first finger 311f1 is larger than the width of the third portion (second connection portion) P3 of the second finger 311f2. Thus, for example, when the solar cell module 100 is manufactured using the solar cell element 31 according to the first embodiment, even if the first wiring material 32 joined to the bus bar portion 311b applies force to the bus bar portion 311b, the occurrence of disconnection in the first portion P1 connected to the first end portion Ep1 among the plurality of first fingers 311f1 can be reduced. As a result, the reliability can be improved by improving the durability in the solar cell element 31 and the solar cell module 100. In addition, for example, compared with a configuration in which all the fingers 311f have the same and large width or a configuration in which all the fingers 311f have the same structure as the first fingers 311f1, the amount of sunlight that is blocked by the plurality of second fingers 311f2 and that enters the semiconductor substrate 310 can be reduced. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved. Therefore, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved. In addition, the material required to form the plurality of finger portions 311f can also be reduced.

[0241] In the solar cell module 100 according to the first embodiment, the width of the first portion (first connection portion) P1 of the first finger portion 311f1 is larger than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. Therefore, it is considered that the stress applied to the first portion P1 of the first finger portion 311f1 is likely to be reduced regardless of whether the portion constituting the third end E3 of the first wiring member 32 applies a force to the first end portion Ep1 in either the -Y direction as the first direction or the +Y direction as the second direction.

[0242] Furthermore, for example, even if the first end portion Ep1 of the bus bar portion 311b is partially peeled off from the semiconductor substrate 310 due to the moist heat stress, if the width of the first portion (first connection portion) P1 is large, the time until the first portion (first connection portion) P1 is disconnected may be prolonged. Here, for example, if the width of the first portion (first connection portion) P1 is larger than the width of the third portion P3, the width of the first portion (first connection portion) P1 may be increased.

[0243] Thus, among the plurality of first finger portions 311f1, it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the first end portion Ep1.

[0244] As a result, in the solar cell element 31 and the solar cell module 100, the reliability can be improved by improving the durability. In addition, compared with, for example, a method in which all the finger-shaped portions 311f have an equal and large width, or a method in which all the finger-shaped portions 311f have the same structure as the first finger-shaped portion 311f1, the amount of sunlight incident on the semiconductor substrate 310 and blocked by the plurality of second finger-shaped portions 311f2 can be reduced. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved. Therefore, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved. In addition, the material required to form the plurality of finger-shaped portions 311f can also be reduced.

[0245] <2. Other embodiments>

[0246] The present disclosure is not limited to the above-described first embodiment, and various changes and improvements can be made without departing from the gist of the present disclosure.

[0247] <2-1. Second embodiment>

[0248] In the solar cell element 31 according to the first embodiment, for example, Fig.15 As shown, the first area A1 may include the second end portion Ep2 of the bus bar portion 311b located on the second end E2 side instead of the first end portion Ep1 of the bus bar portion 311b located on the first end E1 side. Also, for example, the plurality of first finger portions 311f1 may include two or more first finger portions 311f1 connected to the second end portion Ep2.

[0249] In the solar cell element 31 according to the second embodiment, for example, the second end portion Ep2 constituting the first region A1 includes a first island portion Ip11, which is an island portion Ip1 located closest to the second end E2 among a plurality of island portions Ip1 in one bus bar portion 311b. In addition, the second region A2 includes an island portion Ip1 different from the first island portion Ip11 among a plurality of island portions Ip1 in one bus bar portion 311b. Fig.15 In the example of FIG. 3 , in one bus bar portion 311 b, the second region A2 includes all island portions Ip1 except the first island portion Ip11 among the plurality of island portions Ip1. More specifically, the second region A2 includes the second island portion Ip12, the third island portion Ip13, the fourth island portion Ip14, the fifth island portion Ip15, the sixth island portion Ip16, and the seventh island portion Ip17.

[0250] In the solar cell element 31 according to the second embodiment, for example, the plurality of first finger portions 311f1 are connected to the first island portion Ip11, which is the island portion Ip1 located closest to the second end E2 among the plurality of island portions Ip1 in one bus bar portion 311b. Furthermore, for example, the first portion P1 of the first finger portion 311f1 is connected to the first island portion Ip11, which is the island portion Ip1 located closest to the second end E2 among the plurality of island portions Ip1 in one bus bar portion 311b. More specifically, for example, each first finger portion 311f1 is connected to the +X direction side, which is the third direction, and the -X direction side, which is the fourth direction, of the first island portion Ip11. Furthermore, for example, each first finger portion 311f1 includes two first portions P1, which are connected to the +X direction side, which is the third direction, and the -X direction side, which is the fourth direction, of the first island portion Ip11. More specifically, for example, each first finger-shaped portion 311f1 includes: a first portion P1 connected to the +X direction side of the first island-shaped portion Ip11, which is the third direction; and a first portion P1 connected to the -X direction side of the first island-shaped portion Ip11, which is the fourth direction. In addition, for example, the second portion P2 of the first finger-shaped portion 311f1 is separated from the island-shaped portion Ip1 located closest to the second end E2 among the plurality of island-shaped portions Ip1 in one bus bar portion 311b, that is, the first island-shaped portion Ip11. In each first finger-shaped portion 311f1, for example, the second portion P2 is a portion different from the first portion P1.

[0251] In addition, in the solar cell element 31 according to the second embodiment, for example, a plurality of second finger portions 311f2 are respectively connected to an island portion Ip1 different from the first island portion Ip11 among a plurality of island portions Ip1 in one bus bar portion 311b. Furthermore, a third portion P3 of the second finger portion 311f2 is connected to an island portion Ip1 different from the first island portion Ip11 among a plurality of island portions Ip1 in one bus bar portion 311b. More specifically, for example, each second finger portion 311f2 is respectively connected to the +X direction side, which is the third direction, and the -X direction side, which is the fourth direction, of an island portion Ip1 different from the first island portion Ip1 among a plurality of island portions Ip1 in one bus bar portion 311b. Moreover, for example, each second finger-shaped portion 311f2 includes two third portions P3 connected to the +X direction side as the third direction and the -X direction side as the fourth direction of an island-shaped portion Ip1 different from the first island-shaped portion Ip11 among the plurality of island-shaped portions Ip1. More specifically, for example, each second finger-shaped portion 311f2 includes: one third portion P3 connected to the +X direction side as the third direction of an island-shaped portion Ip1 different from the first island-shaped portion Ip11; and one third portion P3 connected to the -X direction side as the fourth direction of an island-shaped portion Ip1 different from the first island-shaped portion Ip11. In addition, for example, the fourth portion P4 of the second finger-shaped portion 311f2 is separated from the island-shaped portion Ip1 different from the first island-shaped portion Ip11 among the plurality of island-shaped portions Ip1 in one bus bar portion 311b. In each second finger-shaped portion 311f2, the fourth portion P4 is, for example, a portion different from the third portion P3.

[0252] In the solar cell element 31 according to the second embodiment, as in the solar cell element 31 according to the first embodiment, the width of the third portion P3 is smaller than the width of the first portion P1 in the -Y direction, which is the first direction. In other words, the width of the first portion (first connection portion) P1 of the first finger 311f1, which is a part of the plurality of finger portions 311f, is selectively increased. Thus, for example, compared with a configuration in which all the finger portions 311f have the same and large width or a configuration in which all the finger portions 311f have the same structure as the first finger portion 311f1, the amount of sunlight incident on the semiconductor substrate 310 that is blocked by the plurality of second finger portions 311f2 is reduced. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved. In addition, the material required to form the plurality of finger portions 311f can be reduced. From another point of view, for example, the width of the first portion P1 of the first finger 311f1 is larger than the width of the third portion P3 of the second finger 311f2. Thus, for example, when the solar cell element 31 according to the second embodiment is used to manufacture the solar cell module 100, even if the first wiring material 32 bonded to the bus bar portion 311b applies a force to the bus bar portion 311b, it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the first area A1 among the plurality of first finger portions 311f1.

[0253] As a result, the durability of the solar cell element 31 and the solar cell module 100 can be improved, thereby improving the reliability. Therefore, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved.

[0254] The solar cell element 31 according to the second embodiment can be realized by, for example, rotating the solar cell element 31 according to the first embodiment by 180 degrees around the Z axis.

[0255] The solar cell module 100 according to the second embodiment can be manufactured, for example, based on the manufacturing method of the solar cell module 100 according to the first embodiment, using the solar cell element 31 according to the second embodiment instead of using the solar cell element 31 according to the first embodiment. In this case, for example, in a manner substantially similar to the first embodiment, Fig.16 As shown, the first wiring material 32 is joined to the bus bar portion 311b. Here, the first wiring material 32 includes a portion on the third end E3 side joined to the first end portion Ep1 (for example, the seventh island portion Ip17) of the bus bar portion 311b.

[0256] Here, for example, it is assumed that the solar cell module 100 is installed outdoors for use. In this case, for example, during the day, the temperature of the solar cell module 100 rises due to the irradiation of the solar cell module 100 with sunlight and the power generation in the solar cell module 100 corresponding to the irradiation with sunlight. On the other hand, at night, the solar cell module 100 is not irradiated with sunlight, and the temperature of the solar cell module 100 decreases. Therefore, for example, expansion due to the increase in temperature and contraction due to the decrease in temperature are repeated in various parts of the solar cell module 100. That is, due to the difference in thermal expansion coefficients corresponding to the materials constituting the various parts of the solar cell module 100, stress is repeatedly applied and relaxed in the solar cell module 100.

[0257] For example, it is assumed that the material of the sealing material 4 is EVA. For example, the instantaneous linear expansion coefficient of EVA is 16×10 -5 [1 / K] to 20×10 -5 Therefore, in the solar cell module 100, the sealing material 4 may expand greatly due to a temperature rise.

[0258] For example, the portion of the sealing material 4 located between the first solar cell element 31 and the second solar cell element 31 adjacently arranged in the -Y direction as the first direction expands due to the rise in temperature. In this case, for example, near the gap between the first solar cell element 31 and the second solar cell element 31 in the first wiring material 32 that electrically connects the first solar cell element 31 and the second solar cell element 31, a force that stretches in the +Z direction is applied to the portion of the first wiring material 32 that is joined to the bus bar portion 311b through the first joining portion 321, and a force that stretches in the -Z direction is applied to the portion of the first wiring material 32 that is joined to the second output portion 312b through the second joining portion 322. As a result, at the second end portion Ep2 on the second end E2 side near the second solar cell element 31 in the bus bar portion 311b of the first solar cell element 31, the bus bar portion 311b may partially peel off from the semiconductor substrate 310 starting from the second end E2 side. In other words, peeling may occur between the semiconductor substrate 310 and the first electrode 311 starting from the second end E2 side. Thereafter, the temperature rises in accordance with the irradiation of sunlight and power generation during the day, and the temperature drops at night, and the thermal expansion and thermal contraction of the first wiring material 32 are repeated. At this time, the portion of the bus bar portion 311b that is peeled off from the semiconductor substrate 310 is also displaced in accordance with the displacement caused by the thermal expansion and thermal contraction of the first wiring material 32. In addition, the portion of the bus bar portion 311b that is peeled off from the semiconductor substrate 310 cannot withstand the load caused by the displacement, and thus stress is generated in the connection portion of the finger portion 311f that is not peeled off from the semiconductor substrate 310 and the bus bar portion 311b that is partially peeled off from the semiconductor substrate 310.

[0259] As a result of the above, for example, the second end portion Ep2 located on the second end E2 side near the second solar cell element 31 in the bus bar portion 311b of the first solar cell element 31 may be relatively greatly displaced by the first wiring material 32. Therefore, for example, in the first solar cell element 31, relatively large stress may be generated in the first portion P1 of the first finger portion 311f1 connected to the second end portion Ep2 (for example, the first island portion Ip11).

[0260] More specifically, for example, the portion of the sealing material 4 located between the first solar cell element 31a and the second solar cell element 31b arranged adjacently expands due to a rise in temperature. In this case, for example, near the gap between the first solar cell element 31a and the second solar cell element 31b in the first wiring material 32 that electrically connects the first solar cell element 31a and the second solar cell element 31b arranged adjacently, a force that stretches in the +Z direction is applied to the portion of the first wiring material 32 that is joined to the bus bar portion 311b through the first joining portion 321, and a force that stretches in the -Z direction is applied to the portion of the first wiring material 32 that is joined to the second output portion 312b through the second joining portion 322. As a result, at the second end portion Ep2 on the second end E2 side of the bus bar portion 311b of the first solar cell element 31a located near the second solar cell element 31b, the bus bar portion 311b may be partially peeled off from the semiconductor substrate 310 starting from the second end E2 side. In other words, there is a possibility that peeling may occur between the semiconductor substrate 310 and the first electrode 311 starting from the second end E2 side. After that, the temperature rises in accordance with the irradiation of sunlight and power generation during the day, and the temperature drops at night, and the thermal expansion and thermal contraction of the first wiring material 32 are repeated. At this time, the portion of the bus bar portion 311b peeled from the semiconductor substrate 310 is also displaced in a manner corresponding to the displacement caused by the thermal expansion and thermal contraction of the first wiring material 32. In addition, the portion of the bus bar portion 311b peeled from the semiconductor substrate 310 cannot withstand the load caused by the displacement, so stress is generated in the connection portion of the finger portion 311f that has not been peeled off and the bus bar portion 311b that has been partially peeled off from the semiconductor substrate 310.

[0261] As a result of the above, for example, the second end portion Ep2 on the second end E2 side near the second solar cell element 31b in the bus bar portion 311b of the first solar cell element 31a may be relatively greatly displaced by the first wiring material 32. Therefore, for example, in the first solar cell element 31a, relatively large stress may be generated in the first portion P1 of the first finger portion 311f1 connected to the second end portion Ep2 (for example, the first island portion Ip11).

[0262] In contrast, in the solar cell module 100 according to the second embodiment, the width of the first portion (first connection portion) P1 of the first finger portion 311f1 is larger than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. Therefore, for example, even if a relatively large force is applied to the second end portion Ep2 of the bus bar portion 311b, the stress applied to the first portion P1 of the first finger portion 311f1 connected to the second end portion Ep2 (for example, the first island portion Ip11) may be reduced.

[0263] Furthermore, for example, even if the second end portion Ep2 of the bus bar portion 311b is partially peeled off from the semiconductor substrate 310 due to the moist heat stress, if the width of the first portion (first connection portion) P1 is large, the time until the first portion (first connection portion) P1 is disconnected may be prolonged. Here, for example, if the width of the first portion (first connection portion) P1 is larger than the width of the third portion P3, the width of the first portion (first connection portion) P1 may be increased.

[0264] Thus, among the plurality of first finger portions 311 f 1 , it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the second end portion Ep2 (for example, the first island portion Ip11 ).

[0265] As a result, in the solar cell element 31 and the solar cell module 100 , the reliability can be improved by improving the durability.

[0266] Furthermore, from another point of view, in the solar cell module 100 according to the first embodiment, the width of the third portion (second connection portion) P3 of the second finger 311f2 is smaller than the width of the first portion (first connection portion) P1 of the first finger 311f1. In other words, the width of a portion of the fingers 311f, that is, the first portion (first connection portion) P1 of the first finger 311f1, is selectively increased. Therefore, for example, compared with a configuration in which all the fingers 311f have the same and large width or a configuration in which all the fingers 311f have the same structure as the first finger 311f1, the amount of sunlight incident on the semiconductor substrate 310 that is blocked by the plurality of second fingers 311f2 is reduced. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved.

[0267] This can improve the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100. In addition, the material required to form the plurality of finger portions 311f can be reduced.

[0268] Here, for example, consider a case where the first wiring material 32 is joined to the bus bar portion 311b in a state where the first wiring material 32 is entirely offset in the +X direction as the third direction or the -X direction as the fourth direction relative to the center of the bus bar portion 311b in the +X direction as the third direction. In this case, for example, the position of the first wiring material 32 joined to the second end portion Ep2 (for example, the first island portion Ip11) is offset from the center in the width direction of the second end portion Ep2 (for example, the first island portion Ip11). The width direction may be a direction along the +X direction as the third direction. Therefore, sometimes the first wiring material 32 approaches the first finger portion 311f1, and the force applied by the first wiring material 32 to the second end portion Ep2 (for example, the first island portion Ip11) is easily applied to the first portion P1. Even in this case, if the width of the first portion (first connection portion) P1 of the first finger portion 311f1 is larger than the width of the third portion (second connection portion) P3 of the second finger portion 311f2, the stress applied to the first portion P1 may be reduced.

[0269] Furthermore, for example, even if the second end portion Ep2 of the bus bar portion 311b is partially peeled off from the semiconductor substrate 310 due to the moist heat stress, if the width of the first portion (first connection portion) P1 is large, the time until the first portion (first connection portion) P1 is disconnected may be prolonged. Here, for example, if the width of the first portion (first connection portion) P1 is larger than the width of the third portion P3, the width of the first portion (first connection portion) P1 may be increased.

[0270] Therefore, among the plurality of first fingers 311 f 1 , it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the second end portion Ep2 (for example, the first island portion Ip11 ).

[0271] However, as described above, in the solar cell module 100, for example, a relatively large force is applied to the second end portion Ep2 (for example, the first island portion Ip11) by the first wiring material 32, and stress concentration may occur in the first portion P1 of the first finger portion 311f1 connected to the second end portion Ep2 (for example, the first island portion Ip11).

[0272] In contrast, in the state of the solar cell element 31 according to the second embodiment before manufacturing the solar cell module 100, the width of the first portion (first connection portion) P1 of the first finger portion 311f1 connected to the second end portion Ep2 (for example, the first island portion Ip11) in the bus bar portion 311b is greater than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. Therefore, when the solar cell module 100 is manufactured using the solar cell element 31 according to the second embodiment, for example, even if the first wiring member 32 applies a relatively large force to the second end portion Ep2 (for example, the first island portion Ip11), the stress applied to the first portion P1 of the first finger portion 311f1 connected to the second end portion Ep2 (for example, the first island portion Ip11) may be reduced.

[0273] Furthermore, for example, even if the second end portion Ep2 of the bus bar portion 311b is partially peeled off from the semiconductor substrate 310 due to the moist heat stress, if the width of the first portion (first connection portion) P1 is large, the time until the first portion (first connection portion) P1 is disconnected may be prolonged. Here, for example, if the width of the first portion (first connection portion) P1 is larger than the width of the third portion P3, the width of the first portion (first connection portion) P1 may be increased.

[0274] Thus, among the plurality of first finger portions 311 f 1 , it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the second end portion Ep2 (for example, the first island portion Ip11 ).

[0275] As a result, in the solar cell element 31 and the solar cell module 100 , the reliability can be improved by improving the durability.

[0276] Furthermore, from another point of view, in the state of the solar cell element 31 according to the second embodiment before the solar cell module 100 is manufactured, the width of the third portion (second connection portion) P3 of the second finger 311f2 is smaller than the width of the first portion (first connection portion) P1 of the first finger 311f1. In other words, the width of a part of the fingers 311f among the plurality of fingers 311f, that is, the first portion (first connection portion) P1 of the first finger 311f1 is selectively increased. Therefore, when the solar cell module 100 is manufactured using the solar cell element 31 according to the second embodiment, for example, compared with a configuration in which all the fingers 311f have the same and large width or a configuration in which all the fingers 311f have the same structure as the first finger 311f1, the amount of sunlight incident on the semiconductor substrate 310 that is blocked by the plurality of second fingers 311f2 is reduced. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved. Therefore, it is possible to improve the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100. In addition, it is also possible to reduce the material required to form the plurality of finger portions 311f.

[0277] In other words, assuming that the solar cell element 31 according to the second embodiment is used to manufacture the solar cell module 100, the solar cell element 31 according to the second embodiment has a structure suitable for improving the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100. That is, according to the solar cell element 31 according to the second embodiment, it is possible to improve the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100. In addition, it is also possible to reduce the material required to form the plurality of finger-shaped portions 311f.

[0278] In addition, here, for example, when the bus bar portion 311b includes the second protruding portion Dp2, the first wiring material 32 may be joined to the second protruding portion Dp2. In this case, the width of the ninth portion (fifth connection portion) P9 of the fifth finger portion 311f5 connected to the second protruding portion Dp2 in the bus bar portion 311b may be greater than the width of the tenth portion (fifth thin line portion) P10 of the fifth finger portion 311f5. Moreover, the width of the ninth portion (fifth connection portion) P9 of the fifth finger portion 311f5 may be greater than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. Thus, for example, in the fifth finger portion 311f5, the occurrence of disconnection in the ninth portion P9 connected to the second protruding portion Dp2 can be reduced. As a result, in the solar cell element 31 and the solar cell module 100, the reliability can be improved by improving the durability. Here, for example, the second end portion Ep2 in the bus bar portion 311b may include the second protruding portion Dp2.

[0279] <2-2. Third embodiment>

[0280] In the above embodiments, for example, Fig.17 As shown, the first area A1 may include both the first end portion Ep1 and the second end portion Ep2 of a bus bar portion 311b. Also, for example, the plurality of first finger portions 311f1 may include two or more first finger portions 311f1 connected to the first end portion Ep1 and two or more first finger portions 311f1 connected to the second end portion Ep2.

[0281] In this case, for example, the first end portion Ep1 constituting the first region A1 includes an island portion Ip1 located closest to the first end E1 among a plurality of island portions Ip1 in a bus bar portion 311b, namely, the seventh island portion Ip17. For example, the second end portion Ep2 constituting the first region A1 includes an island portion Ip1 located closest to the second end E2 among a plurality of island portions Ip1 in a bus bar portion 311b, namely, the first island portion Ip11. Furthermore, for example, the second region A2 includes an island portion Ip1 different from the first island portion Ip11 and the seventh island portion Ip17 among a plurality of island portions Ip1 in a bus bar portion 311b. Fig.17 In the example of FIG. 3 , in one bus bar portion 311 b, the second region A2 includes all island portions Ip1 except the first island portion Ip11 and the seventh island portion Ip17 among the plurality of island portions Ip1. More specifically, the second region A2 includes the second island portion Ip12, the third island portion Ip13, the fourth island portion Ip14, the fifth island portion Ip15, and the sixth island portion Ip16.

[0282] If this structure is adopted, for example, two or more first finger-shaped portions 311f1 having the same characteristics are respectively connected to a pair of first end portions Ep1 and second end portions Ep2 in the Y direction, which is the long side direction of the bus bar portion 311b. As a result, when the solar cell element 31 involved in the third embodiment is used to manufacture the solar cell module 100, the occurrence of errors in the desired direction of arranging the solar cell element 31 can be reduced. As a result, for example, the operability in the manufacture of the solar cell module 100 can be improved. In addition, for example, the constraints on the design of the solar cell module 100 can be reduced.

[0283] In this case, it is possible to reduce the occurrence of disconnection in the first portion P1 connected to the first end portion Ep1 and the second end portion Ep2, respectively, among the plurality of first finger portions 311f1.

[0284] The solar cell module 100 according to the third embodiment can be manufactured, for example, based on the manufacturing method of the solar cell module 100 according to each of the above embodiments, using the solar cell element 31 according to the third embodiment instead of the solar cell element 31 according to each of the above embodiments. In this case, for example, in the same manner as in the above embodiments, Fig.18 As shown, the first wiring material 32 is joined to the bus bar portion 311b. Thus, the first wiring material 32 includes a portion on the third end E3 side joined to the first end portion Ep1 (e.g., the seventh island portion Ip17) of the bus bar portion 311b, and a portion joined to the second end portion Ep2 (e.g., the first island portion Ip11) of the bus bar portion 311b.

[0285] According to the solar cell module 100 according to the third embodiment, for example, it is possible to obtain operations and effects that are the same as or similar to those of the solar cell modules 100 according to the first embodiment and the second embodiment.

[0286] In addition, here, for example, the bus bar portion 311 b may include a first protruding portion Dp1 and a second protruding portion Dp2 .

[0287] In this case, for example, the width of the seventh portion (fourth connection portion) P7 of the fourth finger portion 311f4 connected to the first protruding portion Dp1 in the bus bar portion 311b may be greater than the width of the eighth portion (fourth thin line portion) P8 of the fourth finger portion 311f4. Also, for example, the width of the seventh portion (fourth connection portion) P7 of the fourth finger portion 311f4 may be greater than the width of the third portion (second thin line portion) P3 of the second finger portion 311f2. Thus, for example, in the fourth finger portion 311f4, the occurrence of disconnection in the seventh portion P7 connected to the first protruding portion Dp1 can be reduced. As a result, in the solar cell element 31 and the solar cell module 100, the reliability can be improved by improving the durability.

[0288] In addition, for example, the width of the ninth portion (fifth connection portion) P9 of the fifth finger portion 311f5 connected to the second protruding portion Dp2 in the bus bar portion 311b may be greater than the width of the tenth portion (fifth thin line portion) P10 of the fifth finger portion 311f5. Also, for example, the width of the ninth portion (fifth connection portion) P9 of the fifth finger portion 311f5 may be greater than the width of the third portion (second thin line portion) P3 of the second finger portion 311f2. Thus, for example, in the fifth finger portion 311f5, the occurrence of disconnection in the ninth portion P9 connected to the second protruding portion Dp2 can be reduced. As a result, in the solar cell element 31 and the solar cell module 100, the reliability can be improved by improving the durability. Here, for example, the first end portion Ep1 in the bus bar portion 311b may include the first protruding portion Dp1, and the second end portion Ep2 in the bus bar portion 311b may include the second protruding portion Dp2.

[0289] <2-3. Other embodiments>

[0290] In the solar cell element 31 according to each of the above-mentioned embodiments, for example, Fig.19 As shown, the first area A1 may also include a part of the connecting parts Cp1 among the multiple connecting parts Cp1. Here, for example, the connecting part Cp1 included in the first area A1 among the multiple connecting parts Cp1 is set as the first connecting part Cp1A. In addition, for example, the third finger 311f3 connected to the first connecting part Cp1A among the multiple third finger parts 311f3 is set as the third A finger 311f3A. In addition, for example, the fifth part (third connecting part) P5 in the third A finger 311f3A is set as the fifth A part (also called the third A connecting part) P5A. In this case, for example, in the third A finger 311f3A connected to the first connecting part Cp1A, the width of the fifth A part (third A connecting part) P5A is greater than the width of the sixth part (third thin line part) P6. In addition, for example, the width of the fifth A portion (third A connection portion) P5A of the third A finger portion 311f3A connected to the first connection portion Cp1A is greater than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. As a result, in the third A finger portion 311f3A, the occurrence of disconnection in the fifth A portion P5A can be reduced. As a result, in the solar cell element 31 and the solar cell module 100, the reliability can be improved by improving the durability.

[0291] Here, for example, in the case where the first region A1 includes the first end portion Ep1, the first end portion Ep1 may also include the first connection portion Cp1A. In this case, for example, a method may be adopted in which the first end portion Ep1 includes a connection portion Cp1 located closest to the first end E1 among a plurality of connection portions Cp1 in one bus bar portion 311b as the first connection portion Cp1A. More specifically, for example, the following method may be adopted: the first end portion Ep1 includes a seventh island portion Ip17, which is an island portion Ip1 located closest to the first end E1 among a plurality of island portions Ip1 in one bus bar portion 311b, and includes a connection portion Cp1 connected to the seventh island portion Ip17 as the first connection portion Cp1A. In addition, for example, in the case where the first region A1 includes the second end portion Ep2, the second end portion Ep2 may also include the first connection portion Cp1A. In this case, for example, the second end portion Ep2 may include a connection portion Cp1 located closest to the second end E2 among a plurality of connection portions Cp1 in one bus bar portion 311b as the first connection portion Cp1A. More specifically, for example, the second end portion Ep2 may include a first island portion Ip11, which is an island portion Ip1 located closest to the second end E2 among a plurality of island portions Ip1 in one bus bar portion 311b, and a connection portion Cp1 connected to the first island portion Ip11 as the first connection portion Cp1A.

[0292] In the above embodiments, for example, Fig. 20As shown, the width of the first portion P1 may not be constant between the plurality of first fingers 311f1 connected to the first region A1. For example, in the solar cell element 31, the width of the first portion P1 may gradually or stepwise increase as the first fingers 311f1 that are located in the -Y direction as the first direction and / or the +Y direction as the second direction are located. For example, in the case where the first region A1 includes the first end portion Ep1, the width of the first portion P1 may gradually or stepwise increase as the first fingers 311f1 that are closer to the first end E1 are located. For example, in the case where the first region A1 includes the second end portion Ep2, the width of the first portion P1 may gradually or stepwise increase as the first fingers 311f1 that are closer to the second end E2 are located. Thus, for example, the plurality of finger portions 311f can be strengthened according to the ease of stress concentration in the plurality of finger portions 311f caused by the force applied to the bus bar portion 311b from the first wiring material 32 in the state of the solar cell module 100. As a result, the occurrence of wire breakage in the plurality of finger portions 311f can be reduced. In addition, by selectively thickening the portion of the plurality of finger portions 311f connected to the bus bar portion 311b as needed, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved, and the material required to form the plurality of finger portions 311f can also be reduced.

[0293] In the above embodiments, for example, Fig. 20As shown, the width of the third portion P3 may not be constant between the plurality of second fingers 311f2 connected to the second region A2. For example, in the solar cell element 31, the width of the third portion P3 may gradually or stepwise increase as the second fingers 311f2 are located in the -Y direction as the first direction and / or the +Y direction as the second direction. For example, in the case where the first region A1 includes the first end portion Ep1, the width of the third portion P3 may gradually or stepwise increase as the second fingers 311f2 are located closer to the first end E1. For example, in the case where the first region A1 includes the second end portion Ep2, the width of the third portion P3 may gradually or stepwise increase as the second fingers 311f2 are located closer to the second end E2. Thus, for example, the plurality of finger portions 311f can be strengthened according to the ease of stress concentration in the plurality of finger portions 311f caused by the force applied to the bus bar portion 311b from the first wiring material 32 in the state of the solar cell module 100. As a result, the occurrence of wire breakage in the plurality of finger portions 311f can be reduced. In addition, by selectively thickening the portion of the plurality of finger portions 311f connected to the bus bar portion 311b as needed, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved, and the material required to form the plurality of finger portions 311f can also be reduced.

[0294] In the above embodiments, for example, Fig. 20As shown, the width of the fifth portion P5 may not be constant between the plurality of third fingers 311f3 connected to the connection portion Cp1. For example, in the solar cell element 31, the width of the fifth portion P5 may gradually or stepwise increase as the third fingers 311f3 are located in the -Y direction as the first direction and / or the +Y direction as the second direction. For example, in the case where the first region A1 includes the first end portion Ep1, the width of the fifth portion P5 may gradually or stepwise increase as the third fingers 311f3 are closer to the first end E1. For example, in the case where the first region A1 includes the second end portion Ep2, the width of the fifth portion P5 may gradually or stepwise increase as the third fingers 311f3 are closer to the second end E2. Thus, for example, the plurality of fingers 311f can be strengthened according to the ease of stress concentration in the plurality of fingers 311f caused by the force applied to the bus bar portion 311b from the first wiring material 32 in the state of the solar cell module 100. As a result, the occurrence of disconnection in the plurality of fingers 311f can be reduced. In addition, by selectively thickening the portion connected to the connection portion Cp1 in the plurality of fingers 311f as needed, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved, and the material required to form the plurality of fingers 311f can also be reduced.

[0295] In the above embodiments, for example, Figure 4 , Fig.15 , Fig.17 , Fig.19 as well as Fig. 20 As shown in FIG. 1 , the width of the first portion P1 in a first finger portion 311f1 may also be constant. In this case, for example, when looking down at the first element surface F1, the first portion P1 may also be rectangular. Fig.21 As shown, the width of the first portion P1 in a first finger-shaped portion 311f1 may not be constant. For example, the width of the first portion P1 may gradually or stepwise increase as it approaches the busbar portion 311b. In this case, for example, when looking down at the first element surface F1, the shape of the first portion P1 may be a polygonal shape such as a triangle or a trapezoid, a shape having a curve such as a semicircle or a semi-ellipse, or a shape that is a combination of a polygonal shape and a shape having a curve. Here, for example, a given statistical value such as the maximum value or average value of the length of the first portion P1 in the -Y direction as the first direction may be applied to the width of the first portion P1.

[0296] In addition, for example, the width of the third portion P3 in one second finger-shaped portion 311f2, the width of the fifth portion P5 in one third finger-shaped portion 311f3, the width of the seventh portion P7 in one fourth finger-shaped portion 311f4, and the width of the ninth portion P9 in one fifth finger-shaped portion 311f5 may be constant or non-constant. The widths of the third portion P3, the fifth portion P5, the seventh portion P7, and the ninth portion P9 may be, for example, gradually or stepwise larger as they approach the bus bar portion 311b. In this case, for example, when looking down at the first element surface F1, the shapes of the third portion P3, the fifth portion P5, the seventh portion P7, and the ninth portion P9 may be polygonal shapes such as triangles or trapezoids, shapes having curves such as semicircular shapes or semi-elliptical shapes, or shapes that are a combination of polygonal shapes and shapes having curves. Here, for example, a given statistical value such as a maximum value or an average value of the length in the -Y direction as the first direction can be applied to the widths of the third portion P3, the fifth portion P5, the seventh portion P7, and the ninth portion P9.

[0297] In the above embodiments, for example, Fig. 22 As shown, the first region A1 may not include any of the first end portion Ep1 and the second end portion Ep2 in the bus bar portion 311b. In other words, for example, in one bus bar portion 311b, the first region A1 and the second region A2 may be located at different positions in the -Y direction, which is the first direction. Even with this structure, for example, the plurality of finger portions 311f can be strengthened according to the ease of stress concentration in the plurality of finger portions 311f caused by the force applied to the bus bar portion 311b from the first wiring material 32 in the state of the solar cell module 100. As a result, the occurrence of disconnection in the plurality of finger portions 311f can be reduced. In addition, by selectively thickening the portion of the finger portions 311f of the plurality of finger portions 311f connected to the bus bar portion 311b, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be improved. Therefore, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved. Furthermore, the material required to form the plurality of fingers 311f can also be reduced.

[0298] In the above embodiments, for example, Fig.23As shown, one bus bar portion 311b may also be composed of a strip-shaped portion along the -Y direction as the first direction. In other words, one bus bar portion 311b may also be composed of a strip-shaped portion having a long side direction along the -Y direction as the first direction. In this case, the first area A1 of one bus bar portion 311b may include, for example, the first end portion Ep1, the second end portion Ep2, or may not include any of the first end portion Ep1 and the second end portion Ep2. Here, for example, in one bus bar portion 311b, all parts other than the first area A1 may be the second area A2. Here, the first end portion Ep1 may be, for example, a portion including the first end E1 when one bus bar portion 311b is equally divided into m (m is a natural number greater than or equal to 3) parts in the -Y direction as the first direction. The second end portion Ep2 may be, for example, a portion including the second end E2 when one bus bar portion 311b is equally divided into m (m is a natural number greater than or equal to 3) parts in the -Y direction as the first direction. Here, for example, if the length (also referred to as the width) of the bus bar portion 311b in the +X direction as the third direction is larger than the width W2 of the first wiring material 32, the first wiring material 32 can be joined to the bus bar portion 311b at a position deviated from the center of the bus bar portion 311b in the direction (also referred to as the width direction) along the +X direction as the third direction. Therefore, for example, when joining the first wiring material 32 to the bus bar portion 311b, it is possible to allow the first wiring material 32 to deviate from the position of the bus bar portion 311b in the +X direction as the third direction and to allow the long side direction of the first wiring material 32 to be slightly inclined with respect to the -Y direction as the first direction.

[0299] In the above embodiments, for example, Figure 4 , Fig.15 , Fig.17 , Figures 19 to 22 As shown in FIG. 1 , the length (width) of the island-shaped portion Ip1 in the +X direction as the third direction may be constant among the plurality of island-shaped portions Ip1. Fig.24As shown, for example, the length (width) of the island portion Ip1 in the +X direction as the third direction may not be constant among a plurality of island portions Ip1. For example, the width of the island portion Ip1 may gradually or stepwise increase as the island portion Ip1 is located in the position that advances in the -Y direction as the first direction and / or the +Y direction as the second direction. For example, the width of the island portion Ip1 may gradually or stepwise increase as the island portion Ip1 is closer to the first end E1, or the width of the island portion Ip1 may gradually or stepwise increase as the island portion Ip1 is closer to the second end E2. Thus, for example, even if the first wiring material 32 is joined to the bus bar portion 311b in a state where the long side direction of the first wiring material 32 is slightly inclined relative to the -Y direction as the first direction, the occurrence of a situation where the first wiring material 32 approaches the finger portion 311f can be reduced. As a result, for example, even if a force is applied to the bus bar portion 311b by the first wiring member 32 in the state of the solar cell module 100, the occurrence of disconnection in the finger portion 311f can be reduced. In addition, for example, the length (width) of the island portion Ip1 in the +X direction, which is the third direction, can be set according to the ease of stress concentration in the plurality of finger portions 311f caused by the force applied to the bus bar portion 311b from the first wiring member 32 in the state of the solar cell module 100. Thus, for example, even if a force is applied to the bus bar portion 311b by the first wiring member 32 in the state of the solar cell module 100, the occurrence of disconnection in the finger portion 311f can be reduced. In addition, in one island portion Ip1, the length (width) of the island portion Ip1 in the +X direction, which is the third direction, may not be constant. For example, the width of the island portion Ip1 may be gradually or stepwise increased in the -Y direction, which is the first direction, and / or the +Y direction, which is the second direction. In other words, the shape of the island portion Ip1 may be a trapezoid.

[0300] In each of the above-mentioned embodiments, for example, the solar cell element 31 may also be a substantially rectangular solar cell element formed by dividing a substantially square solar cell element. Here, for example, by equally dividing a substantially square solar cell element into n (n is a natural number greater than or equal to 2) in the long side direction of the bus bar portion 311b, a substantially rectangular solar cell element can be produced. For example, by dividing the solar cell element 31 involved in the above-mentioned third embodiment into two in the -Y direction as the first direction, the solar cell element 31 involved in the above-mentioned first embodiment and the solar cell element 31 involved in the above-mentioned second embodiment can be produced. In this case, for example, the number of the plurality of solar cell elements 31 included in each solar cell string 30 can be easily increased, and the voltage that can be output by the solar cell module 100 can be easily increased.

[0301] In the above-mentioned embodiments, for example, the third portion P3 in all the second fingers 311f2 is not limited to a smaller width than the first portion P1 in the first finger 311f1. For example, with respect to all the second fingers 311f2 connected to the second area A2, the third portion P3 in a part of the second fingers 311f2 may be not smaller than the first portion P1 in the first finger 311f1, and the third portion P3 in the remaining plurality of second fingers 311f2 may be smaller than the first portion P1 in the first finger 311f1. In this case, a part of the second fingers 311f2 may be other fingers (also referred to as sixth fingers) other than the second fingers 311f2. In addition, the area to which a part of the second fingers 311f2 in the bus bar portion 311b is connected may not be included in the second area A2, but may be another area (also referred to as the third area). Here, if the number of the second finger-shaped portions 311f2 of a part is less than the number of the remaining plurality of second finger-shaped portions 311f2, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved. In addition, the material required to form the plurality of finger-shaped portions 311f can be reduced. Here, the number of the second finger-shaped portions 311f2 of a part can be less than 50% of the number of the second finger-shaped portions 311f2 of all the second finger-shaped portions 311f2, less than 20% of the number of the second finger-shaped portions 311f2 of all the second finger-shaped portions 311f2, or less than 10% of the number of the second finger-shaped portions 311f2 of all the second finger-shaped portions 311f2. For example, the smaller the number of the second finger-shaped portions 311f2 of a part, the more the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved. In addition, the material required to form the plurality of finger-shaped portions 311f can be reduced.

[0302] In the above-mentioned embodiments, for example, in the solar cell element 31, the bus bar portion 311b and the finger portion 311f may cross in a non-orthogonal manner. For example, at the first end portion Ep1 of the bus bar portion 311b, when the width of the bus bar portion 311b gradually increases toward the first end E1, it can also be said that the finger portion 311f connected to the first end portion Ep1 and the bus bar portion 311b cross in a non-orthogonal manner. For example, at the second end portion Ep2 of the bus bar portion 311b, when the width of the bus bar portion 311b gradually increases toward the second end E2, it can also be said that the finger portion 311f connected to the second end portion Ep2 and the bus bar portion 311b cross in a non-orthogonal manner. In addition, for example, the first direction and the third direction may cross in a non-orthogonal manner. In other words, for example, the first direction and the third direction may cross at an angle of 90 degrees or at an angle other than 90 degrees. Angles other than 90 degrees may be, for example, an angle of 75 degrees to less than 90 degrees, an angle of 80 degrees to less than 90 degrees, or an angle of 85 degrees to less than 90 degrees.

[0303] In the above embodiments, for example, Fig.25 As shown, the shape of the second electrode 312 when the second element plane F2 is viewed from above may be the same as or similar to the shape of the first electrode 311 when the first element plane F1 is viewed from above. In other words, the second electrode 312 may be a grid-shaped electrode.

[0304] exist Fig.25In the example of , the second electrode 312 includes a plurality of bus bar portions 312b as a second output portion and a plurality of finger portions 312f as a collector portion. Each bus bar portion 312b is located along the -Y direction as a first direction, and the first direction is along the second surface 310b. In other words, each bus bar portion 312b has a long side direction along the -Y direction as the first direction. From another point of view, each bus bar portion 312b has an elongated shape along the -Y direction as the first direction. The plurality of bus bar portions 312b are arranged in the +X direction as a third direction. The plurality of bus bar portions 312b may also have the same structure respectively. In the case of manufacturing the solar cell module 100 using a plurality of solar cell elements 31, a first wiring material 32 for electrically connecting two adjacent solar cell elements 31 is joined to the bus bar portion 312b. The plurality of finger portions 312f are arranged in the -Y direction as the first direction. The plurality of finger portions 312f are linear portions thinner than the bus bar portion 312b. Each finger portion 312f is connected to the plurality of bus bar portions 312b in a state of crossing the plurality of bus bar portions 312b. In other words, the plurality of finger portions 312f are connected to the bus bar portion 312b in a state of crossing the bus bar portion 312b. Each finger portion 312f is, for example, located along the +X direction as the third direction, and the third direction is along the second surface 310b. In other words, each finger portion 312f has, for example, a long side direction along the +X direction as the third direction. From another point of view, each finger portion 312f has a thin and long linear shape along the +X direction as the third direction. The second electrode 312 may also include an auxiliary electrode 312a located at an outer edge portion along the -X direction and an auxiliary electrode 312a located at an outer edge portion along the +X direction on the second surface 310b. Each auxiliary electrode 311a connects the plurality of fingers 312f to each other. The passivation film 313 may be located in a region of the semiconductor substrate 310 on the first type region 310f where the second electrode 312 is not disposed. The protective film 315 may be located on the passivation film 313.

[0305] In this case, for example, the shape of the bus bar portion 312b of the second electrode 312 when looking down at the second element surface F2 may be the same as or similar to the shape of the bus bar portion 311b of the first electrode 311 when looking down at the first element surface F1. In other words, the bus bar portion 312b of the second electrode 312 may have the first area A1 and the second area A2 similarly to the bus bar portion 311b of the first electrode 311. For example, the shape of the plurality of finger-shaped portions 312f of the second electrode 312 when looking down at the second element surface F2 may be the same as or similar to the shape of the plurality of finger-shaped portions 311f of the first electrode 311 when looking down at the first element surface F1. In other words, the width of the portion connected to the bus bar portion 312b of each of the plurality of fingers 312f (also referred to as first fingers) 312f connected to the first area A1 may be greater than the width of the portion connected to the bus bar portion 312b of each of the plurality of fingers 312f (also referred to as second fingers) 312f connected to the second area A2. In other words, the width of the portion connected to the bus bar portion 312b of each of the plurality of first fingers 312f connected to the first area A1 may be selectively increased. Thus, the occurrence of disconnection in the plurality of fingers 312f of the second electrode 312 can be reduced by the same mechanism as that of the plurality of fingers 311f of the first electrode 311. As a result, the reliability can be improved by improving the durability of the solar cell element 31 and the solar cell module 100.

[0306] Here, when the main component of the material of the bus bar portion 312b is silver, the bus bar portion 312b can be formed by applying silver paste into a desired shape by screen printing or the like, and then firing the silver paste. When the main component of the material of the plurality of finger-shaped portions 312f is aluminum, the plurality of finger-shaped portions 312f can be formed by applying aluminum paste into a desired shape by screen printing or the like, and then firing the aluminum paste. Here, in a plan view of the second element surface F2, the bus bar portion 312b may have a structure in which a portion having silver as a main component is surrounded by a portion having aluminum as a main component. In addition, the main component of the material of the entire second electrode 312 may be silver.

[0307] Here, for example, if the second protective member 2 and the second sealing material 42 have light-transmitting properties, the solar cell element 31 can also perform photoelectric conversion based on the light incident from the back side 10b. In this case, the width of the portion connected to the bus bar portion 312b among the plurality of finger portions 312f in the second electrode 312 connected to the first area A1 is selectively increased, so that the power generation efficiency in the solar cell element 31 and the solar cell module 100 can be improved. Therefore, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved. In addition, the material required to form the plurality of finger portions 312f can also be reduced. Here, for example, one of the first electrode 311 and the second electrode 312 can have a structure including the first area A1 and the second area A2. In the case where the second electrode 312 has the first area A1 and the second area A2 and the first electrode 311 does not have the first area A1 and the second area A2, the names of the first surface 310a and the second surface 310b of the semiconductor substrate 310 can also be reversed.

[0308] In the above-mentioned embodiments, for example, the sealing material 4 may include the first sealing material 41 instead of the second sealing material 42. In this case, the first sealing material 41 is in a state of covering the solar cell section 3 between the first protective member 1 and the second protective member 2. In other words, the first sealing material 41 is in a state of covering the plurality of solar cell elements 31 between the first protective member 1 and the second protective member 2.

[0309] In each of the above-mentioned embodiments, for example, the second protective member 2 may be omitted. In this case, for example, free acids such as acetic acid generated in the sealing material 4 can be released from the sealing material 4 in a gaseous state toward the -Z direction. Thus, for example, the occurrence of adverse conditions in the solar cell section 3 caused by free acids can be reduced. In addition, for example, the first protective member 1 may be omitted. In this case, for example, free acids such as acetic acid generated in the sealing material 4 can be released from the sealing material 4 in a gaseous state toward the +Z direction. Thus, for example, the occurrence of adverse conditions in the solar cell section 3 caused by free acids can be reduced.

[0310] As described above, the solar cell element 31 and the solar cell module 100 involved in the above-mentioned embodiments are described in detail, but the above description is illustrative in all aspects, and the present disclosure is not limited to this. In addition, the above-mentioned various examples can be combined and applied as long as they are not contradictory to each other. Moreover, countless examples that are not exemplified can be assumed without departing from the scope of the present disclosure.

[0311] -Description of Reference Numerals-

[0312] 100 Solar cell modules

[0313] 3 Solar cell unit

[0314] 31 Solar cell elements

[0315] 310 Semiconductor Substrate

[0316] 310a Page 1

[0317] 310b Side 2

[0318] 311 First Electrode

[0319] 311b Busbar

[0320] 311f Finger

[0321] 311f1 First finger

[0322] 311f2 Second finger

[0323] 311f3 Third finger

[0324] 312 second electrode

[0325] 312b Second output portion, bus bar portion

[0326] 312f Finger

[0327] 31a First solar cell element

[0328] 31b Second solar cell element

[0329] 32. First wiring material

[0330] 4 Sealing materials

[0331] A1 First Area

[0332] A2 Second Area

[0333] Cp1 connection part

[0334] E1 First End

[0335] E2 Second terminal

[0336] E3 Third End

[0337] E4 Fourth End

[0338] E5 Fifth Terminal

[0339] E6 Sixth terminal

[0340] Ep1 First end part

[0341] Ep2 The second end

[0342] Ip1 island part.

Claims

1. A solar cell element comprising: A semiconductor substrate having a first surface and a second surface opposite to the first surface; and a first electrode, located on the first surface, The first electrode includes a bus bar portion and a plurality of finger portions, The bus bar portion is arranged along a first direction, and the first direction is along the first surface. The plurality of finger-shaped portions are arranged in the first direction, The plurality of finger portions are linear portions thinner than the bus bar portion, and are connected to the bus bar portion in a state of intersecting the bus bar portion. The bus bar portion includes a first region and a second region whose positions are different from each other in the first direction. The plurality of finger-shaped portions include a plurality of first finger-shaped portions connected to the first area and a plurality of second finger-shaped portions connected to the second area, The plurality of first finger-shaped portions respectively include a first portion connected to the first region and a second portion separated from the first region, The plurality of second finger-shaped portions respectively include a third portion connected to the second region and a fourth portion separated from the second region, The width of the first portion is greater than the width of the third portion.

2. The solar cell element according to claim 1, wherein The bus bar portion has a first end and a second end opposite to the first end in the first direction. The first region includes a first end portion of the bus bar portion located on the first end side, The plurality of first fingers include two or more first fingers connected to the first end portion.

3. The solar cell element according to claim 2, wherein The first region includes a second end portion of the bus bar portion located on the second end side, The plurality of first fingers include two or more first fingers connected to the second end portion.

4. A solar cell module comprising: Solar Cell Division; and a sealing material covering the solar cell portion, The solar cell section includes a first solar cell element, a second solar cell element, and a first wiring material. The first solar cell element and the second solar cell element are separated in a first direction and arranged in a second direction opposite to the first direction, The first wiring material includes a portion bonded to the first solar cell element and a portion bonded to the second solar cell element. The first solar cell element comprises the solar cell element according to claim 2, the second end is located closer to the second solar cell element than the first end in the first direction, The first wiring material has a third end and a fourth end in the first direction, The third end is located along the region of the first solar cell element, The fourth end is located along the region of the second solar cell element, The first wiring material is in a state of being joined to the bus bar portion along the first direction, The first wiring material includes a portion on the third end side joined to the first end portion.

5. A solar cell module comprising: Solar Cell Division; and a sealing material covering the solar cell portion, The solar cell section includes a first solar cell element, a second solar cell element, and a first wiring material. The first solar cell element and the second solar cell element are separated in a first direction and arranged in a second direction opposite to the first direction, The first wiring material includes a portion bonded to the first solar cell element and a portion bonded to the second solar cell element. The first solar cell element comprises the solar cell element according to claim 1, The bus bar portion has a first end and a second end opposite to the first end in the first direction. the second end is located closer to the second solar cell element than the first end in the first direction, The bus bar portion includes a first end portion located on the first end side, The first region includes a second end portion of the bus bar portion located on the second end side, The plurality of first finger-shaped portions include two or more first finger-shaped portions connected to the second end portion, The first wiring material has a third end and a fourth end in the first direction, The third end is located along the region of the first solar cell element, The fourth end is located along the region of the second solar cell element, The first wiring material is in a state of being joined to the bus bar portion along the first direction, The first wiring material includes a portion on the third end side joined to the first end portion.

6. The solar cell module according to claim 5, wherein: the first region includes the first end portion, The plurality of first fingers include two or more first fingers connected to the first end portion.

7. A solar cell module comprising: Solar Cell Division; and a sealing material covering the solar cell portion, The solar cell section includes a first solar cell element, a second solar cell element, and a first wiring material. The first solar cell element and the second solar cell element are separated in a first direction and arranged in a second direction opposite to the first direction, The first wiring material includes a portion bonded to the first solar cell element and a portion bonded to the second solar cell element. The first solar cell element comprises the solar cell element according to claim 1, The bus bar portion includes a first island portion and a second island portion arranged in the first direction, and includes a connecting portion connecting the first island portion and the second island portion, The plurality of fingers include a third finger connected to the connecting portion, The third finger portion comprises: two fifth portions, connected to the connecting portion on a third direction side intersecting the first direction and along the first surface and on a fourth direction side opposite to the third direction, respectively; and a sixth portion, separated from the connecting portion, In the first direction, the width of each of the two fifth portions is greater than the width of the sixth portion, The two fifth portions have a fifth end located in the fourth direction and a sixth end located in the third direction, In the third direction, a length from the fifth end to the sixth end is greater than a width of the first wiring material.

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