Solar cell glass and solar cell module

Abstract

This solar cell element comprises: a semiconductor substrate having first and second surfaces; and a first electrode on the first surface. The first electrode includes a busbar part (311b) positioned in a first direction, and a plurality of finger parts (311f) arranged side by side in the first direction. The busbar part (311b) includes first and second regions (A1, A2) different from each other in position in the first direction. The plurality of finger parts (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 of the first fingers (311f1) includes a first part (P1) connected to the first region (A1), and a second part (P2) separated from the first region (A1). Each of the second fingers (311f2) includes a third part (P3) connected to the second region (A2), and a fourth part (P4) separated from the second region (A2). The first part (P1) is larger in width than the third part (P3).

Description

Cross-reference to related applications

[0001] This application claims the priority of Japanese Application No. 2022-139718 (filed on September 2, 2022), and the entire disclosure of the Japanese application is incorporated herein by reference for this purpose.

Technical Field

[0002] This disclosure relates to solar cell elements and solar cell modules.

Background Art

[0003] There is a solar cell module including a plurality of solar cell elements, a plurality of wiring members, and a sealing material. In this solar cell module, each of the plurality of wiring members electrically connects between two adjacent solar cell elements among the plurality of solar cell elements. The sealing material is positioned in a state of covering the plurality of solar cell elements.

[0004] Each solar cell element includes, for example, a grid-shaped electrode (also referred to as a grid electrode) on the upper surface side of the solar cell element (see, for example, the descriptions of Patent Documents 1 and 2). This grid electrode has a plurality of bus bar portions and a large number of finger portions. The plurality of bus bar portions are arranged substantially parallel to each other, for example, on the upper surface side of the solar cell element. The large number of finger portions are arranged substantially parallel to each other, for example, on the upper surface side of the solar cell element. Each finger portion is substantially orthogonal to the plurality of bus bar portions and is thinner than each of the plurality of bus bar portions. ​​​​​​​​​​​​​​​​​​​Special Publication No. 2015-528645 [Overview of the project]

[0007] Solar cell elements and solar cell modules are disclosed.

[0008] One embodiment 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 busbar portion and a plurality of finger portions. The busbar portion is located along a first direction along the first surface. The plurality of finger portions are arranged in the first direction. Each of the plurality of finger portions is a linear portion thinner than the busbar portion and is connected to the busbar portion in a manner that intersects the busbar portion. The busbar portion includes a first region and a second region whose positions in the first direction are different from each other. 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. Each of the plurality of first finger portions includes a first portion connected to the first region and a second portion separated from the first region. Each of the plurality of second finger portions includes 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. The busbar portion includes a first island-shaped portion and a second island-shaped portion arranged in the first direction, and a connecting portion connecting the first island-shaped portion and the second island-shaped portion. The plurality of finger portions include a third finger portion connected to the connecting portion. The third finger portion includes two fifth portions connected to the connecting portion on the side in the third direction that intersects the first direction and is along the first surface, and on the side in the fourth direction opposite to the third direction, respectively, and a sixth portion that 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.

[0009] One embodiment of a solar cell module comprises 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 teeth, The second solar cell element against They are separated in the first direction. The second solar cell element is relative to the first solar cell element.They are aligned 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 according to the above embodiment. The busbar portion has a first end and a second end opposite to the first end in the first direction. The first region includes the first end portion of the busbar portion located on the first end side. The plurality of first finger portions include two or more first finger 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 joined to the busbar portion along the first direction. The first wiring material includes the portion on the third end side that is joined to the first end portion.

[0010] One embodiment of a solar cell module comprises 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 teeth, The second solar cell element against They are separated in the first direction. The second solar cell element is relative to the first solar cell element.They are aligned 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 according to the above embodiment. The busbar 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 busbar portion includes a first end portion located on the first end side. The first region includes a second end portion of the busbar portion 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 joined to the busbar portion along the first direction. The first wiring material includes the portion on the third end side that is joined to the first end portion.

[0011] One embodiment of a solar cell module comprises 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 teeth, The second solar cell element against They are separated in the first direction. The second solar cell element is relative to the first solar cell element. They are 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. . before Each of the two fifth portions has a fifth end located in the fourth direction and a sixth end located in the third direction. In the third direction, the length from the fifth end to the sixth end is greater than the width of the first wiring material. [Brief explanation of the drawing]

[0012] [Figure 1] FIG. 1 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 in plan. [Figure 2] FIG. 2 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 in plan. [Figure 3] FIG. 3 is a diagram schematically showing an example of a virtual cut surface along the III-III line of the solar cell element of FIGS. 1 and 2. [Figure 4] FIG. 4 is a diagram schematically showing an example of the structure in the IV part of the solar cell element of FIG. 1. [Figure 5] FIG. 5 is a plan view schematically showing an example of the appearance when the solar cell module according to the first embodiment is viewed in plan. [Figure 6] FIG. 6 is a diagram schematically showing an example of a virtual cut surface along the VI-VI line of the solar cell module of FIG. 5. [Figure 7] FIG. 7 is a diagram schematically showing an example of a state where a first wiring material is joined to a bus bar part in the IV part of the solar cell element of FIG. 1. [Figure 8] FIG. 8 is a diagram schematically showing an example of the state of a virtual cut surface during manufacturing in a specific example of the manufacturing method of the solar cell element. [Figure 9] FIG. 9 is a diagram schematically showing an example of the state of a virtual cut surface during manufacturing in a specific example of the manufacturing method of the solar cell element. [Figure 10] FIG. 10 is a diagram schematically showing an example of the state of a virtual cut surface during manufacturing in a specific example of the manufacturing method of the solar cell element. [Figure 11] FIG. 11 is a diagram schematically showing an example of the state of a virtual cut surface during manufacturing in a specific example of the manufacturing method of the solar cell element. [Figure 12] FIG. 12 is a diagram schematically showing an example of the state of a virtual cut surface during manufacturing in a specific example of the manufacturing method of the solar cell element. [Figure 13]FIG. 13 is a diagram schematically showing an example of the state of a virtual cut surface during manufacturing in a specific example of a method for manufacturing a solar cell module according to the first embodiment. [Figure 14] FIG. 14 is a diagram schematically showing an example of the state of a virtual cut surface during manufacturing in a specific example of a method for manufacturing a solar cell module according to the first embodiment. [Figure 15] FIG. 15 is a diagram schematically showing an example of the structure of a portion corresponding to the IV portion of the solar cell element in FIG. 1 among the solar cell elements according to the second embodiment. [Figure 16] FIG. 16 is a diagram schematically showing an example of a state in which a first wiring member is joined to a bus bar portion in a portion corresponding to the IV portion of the solar cell element in FIG. 1 among the solar cell elements according to the second embodiment. [Figure 17] FIG. 17 is a diagram schematically showing an example of the structure of a portion corresponding to the IV portion of the solar cell element in FIG. 1 among the solar cell elements according to the third embodiment. [Figure 18] FIG. 18 is a diagram schematically showing an example of a state in which a first wiring member is joined to a bus bar portion in a portion corresponding to the IV portion of the solar cell element in FIG. 1 among the solar cell elements according to the third embodiment. [Figure 19] FIG. 19 is a diagram schematically showing an example of the structure of a portion corresponding to the IV portion of the solar cell element in FIG. 1 among the solar cell elements according to another embodiment. [Figure 20] FIG. 20 is a diagram schematically showing an example of the structure of a portion corresponding to the IV portion of the solar cell element in FIG. 1 among the solar cell elements according to another embodiment. [Figure 21] FIG. 21 is a diagram schematically showing an example of the structure of a portion corresponding to the IV portion of the solar cell element in FIG. 1 among the solar cell elements according to another embodiment. [Figure 22] FIG. 22 is a diagram schematically showing an example of the structure of a portion corresponding to the IV portion of the solar cell element in FIG. 1 among the solar cell elements according to another embodiment. [Figure 23]Figure 23 is a schematic diagram showing an example of the structure of a portion of a solar cell element corresponding to section IV of the solar cell element in Figure 1, according to another embodiment of the solar cell element. [Figure 24] Figure 24 is a schematic diagram showing an example of the structure of a portion of a solar cell element corresponding to section IV of the solar cell element in Figure 1, according to another embodiment of the solar cell element. [Figure 25] Figure 25 is a schematic diagram showing an example of the structure of a solar cell element when the second element surface is viewed from above according to another embodiment. [Modes for carrying out the invention]

[0013] There is a solar cell module that comprises multiple solar cells, multiple wiring materials, and a encapsulant. In this solar cell module, each of the multiple wiring materials electrically connects two adjacent solar cells among the multiple solar cells. The encapsulant is positioned to cover the multiple solar cells.

[0014] Each solar cell element is equipped with, for example, a grid-like electrode (also called a grid electrode) on its upper surface. This grid electrode has multiple busbar sections and multiple finger sections. The multiple busbar sections are arranged substantially parallel to each other on, for example, the upper surface of the solar cell element. Each of the multiple finger sections has, for example, a linear shape that is thinner than the multiple busbar sections. If the width of the multiple busbar sections is not constant, the statement that each of the multiple finger sections has a linear shape that is thinner than the multiple busbar sections means that each of the multiple finger sections has a linear shape that is thinner than the widest width of the multiple busbar sections. The multiple finger sections are arranged substantially parallel to each other on, for example, the upper surface of the solar cell element. Each finger section is, for example, substantially perpendicular to the multiple busbar sections.

[0015] Each wiring material is joined to the busbar portion of the grid electrode by soldering or other means.

[0016] Incidentally, regarding solar cell elements, for example, it is conceivable to increase the amount of sunlight received that contributes to power generation by making the grid electrodes that block sunlight thinner.

[0017] However, if the grid electrodes are made too thin, there is a possibility that breaks may occur in the grid electrodes.

[0018] Factors that increase the likelihood of disconnection include, for example, in solar cell modules installed outdoors, a decrease in adhesive strength between the busbar and finger sections and the semiconductor substrate due to humidity and / or rainfall-related humidity stress.

[0019] Another contributing factor is the repeated temperature increases during the day due to sunlight irradiation and power generation, and the subsequent temperature decreases at night. In this case, each part of the solar cell module repeatedly expands due to the temperature increase and contracts due to the temperature decrease. At this time, due to differences in the thermal expansion coefficients of the materials constituting each part of the solar cell module, stress can repeatedly occur within the solar cell module. For example, the expansion and contraction of the wiring material and encapsulating material can cause stress on the busbar section of the wiring material.

[0020] Due to the two factors mentioned above, there is a risk that the busbar portion may detach from the semiconductor substrate.

[0021] For example, if the busbar portion, located at the longitudinal end of the wiring material, partially detaches from the semiconductor substrate, the detached portion of the busbar becomes more susceptible to displacement. As a result, particularly large shear stress is generated in the portion of the finger portion connected to the busbar portion (also called the connection portion).

[0022] For example, if the width of the connection point of the finger portion is excessively small, the likelihood of the finger portion breaking at the connection point increases. Also, as the lifespan of the solar cell module and solar cell elements increases, the likelihood of fatigue and breakage of the finger portion at the connection point increases due to repeated stress concentration.

[0023] Furthermore, it is possible that the narrower the width of the finger connection, the greater the concentration of stress at the finger connection, and that the narrower the width of the finger connection, the more likely it is that cracks originating from the stress concentration at the finger connection will propagate and cause the finger to break in a short period of time.

[0024] Furthermore, if a break occurs in the finger section, the output characteristics of the solar cell module will decrease. This decrease in the output characteristics of the solar cell module is also called degradation of the solar cell module's output characteristics.

[0025] One possible approach here is to increase the width of the connection points in each finger section. However, increasing the width of the connection points in each finger section reduces the amount of sunlight received by the solar cell element that contributes to power generation.

[0026] Therefore, there is room for improvement in terms of improving the power generation efficiency and reliability of solar cell elements and solar cell modules.

[0027] Therefore, the inventors of this disclosure have created a technology that can improve the power generation efficiency and reliability of solar cell elements and solar cell modules. This technology will be described below with reference to the drawings, with respect to the first to third embodiments and other embodiments.

[0028] In the drawings, the same reference numerals are used for parts that have the same or nearly identical configuration and function. As a result, redundant explanations will be omitted as appropriate in the following description. The drawings are shown schematically. Figures 1 to 25 are shown in a right-handed XYZ coordinate system. In this XYZ coordinate system, the direction along the longitudinal direction of the busbar portion 311b of the solar cell element 31 is defined as the -Y direction, which is the first direction. The direction opposite to the first direction is defined as the +Y direction, which is the second direction. The direction along the longitudinal direction of the finger portion 311f of the solar cell element 31 is defined as the +X direction, which is the third direction. The direction opposite to the third direction is defined as the -X direction, which is the fourth direction. The direction perpendicular to the first element surface F1 of the solar cell element 31 (also called the normal direction), which is orthogonal to both the -Y direction and the +X direction, is defined as the +Z direction.

[0029] <1. First Embodiment> <1-1. Solar Cell Elements> The solar cell element 31 according to the first embodiment will be described with reference to Figures 1 to 4.

[0030] The solar cell element 31 can convert light energy into electrical energy. The solar cell element 31 has, for example, a plate-like shape.

[0031] As shown in Figures 1 to 3, the solar cell element 31 has a first element surface F1 and a second element surface F2. The second element surface F2 is the surface opposite to the first element surface F1. In the example in Figures 1 to 3, the first element surface F1 is facing the +Z direction, and the second element surface F2 is facing the -Z direction. For example, the first element surface F1 mainly serves as the surface to which light is incident (also called the light-receiving surface or front surface). For example, the second element surface F2 serves 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 shape. Here, the shapes of the first element surface F1 and the second element surface F2 are not limited to a rectangular shape. For example, each corner of the first element surface F1 and the second element surface F2 may be arc-shaped, or may have a chamfered corner. Each of the first element surface F1 and the second element surface F2 has a roughly square shape, for example, with a side length of about 150 millimeters (mm) to 250 mm. Each of the first element surface F1 and the second element surface F2 may also have a roughly rectangular shape, for example.

[0032] As shown in Figures 1 and 3, the solar cell element 31 comprises a semiconductor substrate 310 and a first electrode 311. Furthermore, as shown in Figures 2 and 3, the solar cell element 31 also comprises a second electrode 312.

[0033] <1-1-1. Semiconductor Substrates> The semiconductor substrate 310 has, for example, a first surface 310a and a second surface 310b. The first surface 310a is the surface facing the first element surface F1. The second surface 310b is the surface facing the second element surface F2. In other words, the second surface 310b is the surface opposite to the first surface 310a. The semiconductor substrate 310 has, for example, a plate-like shape.

[0034] The semiconductor substrate 310 can be made of, for example, 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, we assume that crystalline silicon is used for the semiconductor substrate 310. In this case, as shown in Figure 3, the semiconductor substrate 310 mainly has a semiconductor region having a first conductivity type (also called the first type region) 310f and a semiconductor region having a second conductivity type opposite to the first conductivity type (also called the second type region) 310s. The first type region 310f is located, for example, on the second surface 310b side of the semiconductor substrate 310. The second type region 310s is located, for example, on the surface layer of the semiconductor substrate 310 on the first surface 310a side. The surface layer may be the portion that forms the first surface 310a along the first surface 310a of the semiconductor substrate 310. Here, for example, if the first conductivity type is p-type, then the second conductivity type is n-type. For example, if the first conductivity type is n-type, then the second conductivity type is p-type. As a result, the semiconductor substrate 310 has a pn junction located at the interface between the first-type region 310f and the second-type region 310s.

[0035] Each of the first surface 310a and the second surface 310b has a rectangular shape, such as a roughly square shape. Here, the shape of each of the first surface 310a and the second surface 310b is not limited to a rectangular shape. For example, each of the first surface 310a and the second surface 310b may have an arc shape or a shape with chamfered corners. Each of the first surface 310a and the second surface 310b has a roughly square shape, for example, with a side length of about 150 mm to 250 mm. Each of the first surface 310a and the second surface 310b may have a roughly rectangular shape, for example. The thickness of the semiconductor substrate 310 is, for example, about 50 micrometers (μm) to 250 μm.

[0036] <1-1-2. 1st electrode> 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 called thickness) of the first electrode 311 in the +Z direction is, for example, about 0.5 μm to 50 μm.

[0037] The first electrode 311 includes, for example, a busbar portion 311b as a first output portion and a plurality of finger portions 311f as a plurality of first current collectors. More specifically, for example, the first electrode 311 includes a plurality of busbar portions 311b and a plurality of finger portions 311f.

[0038] Each busbar portion 311b is located along the -Y direction, which is the first direction along the first surface 310a. In other words, each busbar portion 311b has a longitudinal direction along the -Y direction, which is the first direction. From another point of view, each busbar portion 311b has an elongated shape along the -Y direction, which is the first direction. For example, multiple busbar portions 311b are arranged in the +X direction, which is the third direction. Each of the multiple busbar portions 311b has, for example, the same structure. When manufacturing a solar cell module 100 (see Figure 5) using multiple solar cell elements 31, a first wiring material 32 (see Figure 5) for electrically connecting two adjacent solar cell elements 31 is joined to the busbar portion 311b.

[0039] The multiple finger portions 311f are aligned in the -Y direction as the first direction. Each of the multiple finger portions 311f is a linear portion thinner than the busbar portion 311b. Each finger portion 311f is connected to the multiple busbar portions 311b in a manner that intersects with them. In other words, each of the multiple finger portions 311f is connected to the busbar portions 311b in a manner that intersects with them. Each finger portion 311f is located, for example, along the +X direction as the third direction along the first surface 310a. In other words, each finger portion 311f has a longitudinal direction along the +X direction as the third direction. From another perspective, each finger portion 311f has an elongated linear shape along the +X direction as the third direction.

[0040] In the example shown in Figure 1, five busbar sections 311b, which are arranged substantially parallel to each other, and multiple finger sections 311f, which are arranged substantially parallel to each other, are positioned substantially orthogonally. In other words, the first electrode 311 may be a grid-shaped electrode. Here, the number of busbar sections 311b on the first electrode 311 is not limited to five. The number of busbar sections 311b on the first electrode 311 may be any number from five to fifteen, for example.

[0041] Here, as shown in Figure 1, the first electrode 311 may have, for example, an auxiliary electrode 311a located along the outer edge in the -X direction on the first surface 310a, and an auxiliary electrode 311a located along the outer edge in the +X direction. Each auxiliary electrode 311a connects, for example, a number of substantially parallel finger portions 311f to each other. Also, for example, an anti-reflective film 314 may be located in the region of the second type region 310s of the semiconductor substrate 310 where the first electrode 311 is not located. The anti-reflective film 314 is an insulating film made of, for example, silicon nitride. For example, as shown in Figures 1 and 3, a passivation film 313 may exist between the second type region 310s of the semiconductor substrate 310 and the anti-reflective film 314. The passivation film 313 is a thin film made of, for example, an oxide or nitride such as aluminum oxide.

[0042] For example, if the main component of the material for the first electrode 311 is silver, the first electrode 311 can be formed by applying a silver paste to a desired shape using a screen printing method or the like, and then firing the silver paste. In this specification, the main component means the component that is present in the largest proportion (also called the content) of the components that make up the substance. For example, the silver paste can be a metal paste containing silver as the main component, an organic vehicle, and glass frit. The multiple busbar portions 311b, multiple finger portions 311f, and two auxiliary electrodes 311a of the first electrode 311 may be formed in separate processes or in the same process.

[0043] <1-1-3.Second electrode> The second electrode 312 is located, for example, on the second element surface F2 side of the semiconductor substrate 310.

[0044] The second electrode 312 includes, for example, a second output section 312b and a second current collector section 312c. More specifically, for example, the second electrode 312 includes a plurality of second output sections 312b and second current collector sections 312c.

[0045] Each second output section 312b is positioned along the -Y direction, which is the first direction. Multiple second output sections 312b are arranged, for example, in the +X direction, which is the third direction. Each second output section 312b includes, for example, multiple electrode sections arranged in a row. In the example in Figure 2, each second output section 312b includes, for example, seven electrode sections arranged in a row.

[0046] The second current collector 312c is located on the second element surface F2 side of the semiconductor substrate 310. The second current collector 312c is located on the second element surface F2 side of the semiconductor substrate 310, covering almost the entire area where the second output unit 312b is not located, except for the portion where the second output unit 312b and the second current collector 312c are connected by overlapping. Note that the second current collector 312c does not need to cover almost the entire area; for example, it may be arranged in a grid pattern.

[0047] Here, for example, as shown in Figures 2 and 3, a passivation film 313 may be present between the first type region 310f of the semiconductor substrate 310 and the second output section 312b and the second current collector section 312c. The passivation film 313 is a thin film composed of, for example, an oxide or nitride such as aluminum oxide. In this case, the passivation film 313 is positioned in a desired pattern between the first type region 310f and the second output section 312b and the second current collector section 312c. Furthermore, a film (also called a protective film) 315 for protecting the passivation film 313 may be present between the passivation film 313 and the second current collector section 312c. The protective film 315 is a thin film composed of, for example, an oxide such as silicon oxide. The protective film 315 is positioned in a desired pattern between the passivation film 313 and the second current collector section 312c. The protective film 315 does not necessarily have to be present between the passivation film 313 and the second output section 312b, as shown in Figure 3. In this case, the protective film 315 has a plurality of holes where the second output section 312b is located. Alternatively, for example, the protective film 315 may be present between the passivation film 313 and the second output section 312b. The passivation film 313 and the protective film 315 have a number of through holes for bringing a portion of the second current collector section 312c into contact with the first type region 310f. The first type region 310f has a region (also called a high-concentration region or BSF (Back Surface Field) region) 310t in the surface layer portion in contact with the second current collector section 312c, where the concentration of the first conductivity type dopant element is higher than in other regions of the first type region 310f.

[0048] For example, if the main component of the material for the second output section 312b is silver, the second output section 312b can be formed by applying a silver paste to a desired shape using a screen printing method or the like, and then firing the silver paste. For example, if the main component of the material for the second current collector section 312c is aluminum, the second current collector section 312c can be formed by applying an aluminum paste to a desired shape using a screen printing method or the like, and then firing the aluminum paste. For example, the aluminum paste can be a metal paste containing metal powder with aluminum as the main component, an organic vehicle, and glass frit.

[0049] <1-1-4. Structure and characteristics of the first electrode> <<Busbar section structure>> As shown in Figure 4, for example, the busbar section 311b includes a first region A1 and a second region A2. The first region A1 and the second region A2 are located at different positions in the -Y direction, which is the first direction. Here, the fact that their positions are different in the -Y direction, which is the first direction, can be rephrased as their Y coordinates being different. In other words, the Y coordinates of the first region A1 and the second region A2 are different. Alternatively, the fact that their positions are different in the -Y direction, which is the first direction, can be rephrased as their distances measured from one end of the busbar section 311b in the Y direction being different. In other words, the distances measured from one end of the busbar section 311b in the Y direction are different for the first region A1 and the second region A2.

[0050] The busbar portion 311b has, for example, a first end (also called the first end) E1 and a second end (also called the second end) E2 in the -Y direction as the first direction. In this case, in the busbar portion 311b, the second end E2 is located on the opposite side from the first end E1 in the -Y direction as the first direction. In other words, the busbar portion 311b has a pair of first ends E1 and second ends E2 in the Y direction. In the example in Figure 4, the first end E1 is the end of the busbar portion 311b in the -Y direction as the first direction, and the second end E2 is the end of the busbar portion 311b in the +Y direction as the second direction. Also, for example, the busbar portion 311b includes a portion (also called the first end portion) Ep1 located on the side of the first end E1. For example, the busbar portion 311b includes the portion Ep2 located on the second end E2 side of the busbar portion 311b (also called the second end portion).

[0051] In the first embodiment, the first region A1 includes, for example, the portion of the busbar portion 311b located on the first end E1 side (also referred to as the first end portion) Ep1. The second region A2 includes, for example, a portion of the busbar portion 311b that is different from the first end portion Ep1.

[0052] In the first embodiment, for example, the busbar portion 311b includes a plurality of island-shaped portions (also called island portions or pad portions) Ip1 arranged in the -Y direction as the first direction. In the example of Figure 4, the busbar portion 311b includes seven island-shaped portions Ip1 as the plurality of island-shaped portions Ip1. The seven island-shaped portions Ip1 include a first island-shaped portion Ip11, a second island-shaped portion Ip12, a third island-shaped portion Ip13, a fourth island-shaped portion Ip14, a fifth island-shaped portion Ip15, a sixth island-shaped portion Ip16, and a seventh island-shaped portion Ip17. The first island-shaped portion Ip11, the second island-shaped portion Ip12, the third island-shaped portion Ip13, the fourth island-shaped portion Ip14, the fifth island-shaped portion Ip15, the sixth island-shaped portion Ip16, and the seventh island-shaped portion Ip17 are arranged in the order described herein in the -Y direction as the first direction. In other words, the busbar portion 311b includes the first island-shaped portion Ip11 and the second island-shaped portion Ip12, which are arranged in the -Y direction as the first direction. Here, the number of island-shaped portions Ip1 in the busbar portion 311b is not limited to seven. For example, the number of island-shaped portions Ip1 in the busbar portion 311b may be any number between three and thirty.

[0053] The first end portion Ep1 constituting the first region A1 includes, for example, the seventh island portion Ip17, which is the island portion Ip1 located furthest to the first end E1 among a plurality of island portions Ip1 in one busbar portion 311b. The second region A2 includes island portions Ip1 that are different from the seventh island portion Ip17 among the plurality of island portions Ip1 in one busbar portion 311b. In the example of Figure 4, in one busbar portion 311b, the second region A2 includes all island portions Ip1 except for the seventh island portion Ip17. 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.

[0054] For example, when the first element surface F1 is viewed from above, each island-like portion Ip1 has a rectangular shape, as an example of a rectangular shape. However, the shape of each island-like portion Ip1 is not limited to a rectangular shape. For example, the corners of each island-like portion Ip1 may be arc-shaped or have a rounded corner shape. The length (also called width) W1 of the island-like portion Ip1 in the third direction, the +X direction, is, for example, about 0.25 mm to 4 mm. The length (also simply called length) of the island-like portion Ip1 in the first direction, the -Y direction, is, for example, about 0.25 mm to 10 mm.

[0055] Furthermore, in the first embodiment, for example, the busbar portion 311b includes a portion (also called a connecting portion) Cp1 that connects two adjacent island-shaped portions Ip1. More specifically, for example, the busbar portion 311b includes a plurality of connecting portions Cp1 that sequentially connect a plurality of island-shaped portions Ip1. In the example of Figure 4, the busbar portion 311b includes six connecting portions Cp1 that sequentially connect seven island-shaped portions Ip1. More specifically, the busbar portion 311b includes a connecting portion Cp1 that connects the first island-shaped portion Ip11 and the second island-shaped portion Ip12. The busbar portion 311b includes a connecting portion Cp1 that connects the second island-shaped portion Ip12 and the third island-shaped portion Ip13. The busbar portion 311b includes a connecting portion Cp1 that connects the third island-shaped portion Ip13 and the fourth island-shaped portion Ip14. The busbar section 311b includes a connecting section Cp1 that connects the fourth island-shaped section Ip14 and the fifth island-shaped section Ip15. The busbar section 311b also includes a connecting section Cp1 that connects the fifth island-shaped section Ip15 and the sixth island-shaped section Ip16. The busbar section 311b also includes a connecting section Cp1 that connects the sixth island-shaped section Ip16 and the seventh island-shaped section Ip17. Here, the number of connecting sections Cp1 in the busbar section 311b is not limited to six. For example, the number of connecting sections Cp1 in the busbar section 311b can be appropriately set according to the number of island-shaped sections Ip1.

[0056] For example, when the first element surface F1 is viewed from above, the connecting portion Cp1 has an elongated shape along the -Y direction, which is the first direction. In other words, the connecting portion Cp1 has a longitudinal direction along the -Y direction, which is the first direction, and a transverse direction along the +X direction, which is the third direction. The length (also called width) of the connecting portion Cp1 in the +X direction, which is the third direction, is smaller than the length (width) W1 of the island-shaped portion Ip1 in the +X direction, which is the third direction. This makes it possible to reduce the amount of material required to form the busbar portion 311b, for example. Also, it is possible to reduce the amount of sunlight that is blocked from entering the semiconductor substrate 310 by the busbar portion 311b, for example. For this reason, it is possible to increase the power generation efficiency of the solar cell element 31 and the solar cell module 100, for example. Here, the width of the connecting portion Cp1 is, for example, about 0.01 mm to 0.4 mm. Furthermore, for example, when a solar cell module 100 is manufactured, if a connecting portion Cp1 exists, the reduction in power output from the solar cell element 31 can be reduced even if the first wiring material 32 is not connected to some island-shaped portions Ip1.

[0057] Furthermore, in the example shown in Figure 4, the connecting portion Cp1 connects, for example, the approximately central portions in the +X direction, which is the third direction, of two adjacent island-shaped portions Ip1. More specifically, the connecting portion Cp1 between the first island-shaped portion Ip11 and the second island-shaped portion Ip12 connects the approximately central portions in the +X direction, which is the third direction, of both the first island-shaped portion Ip11 and the second island-shaped portion Ip12. The connecting portion Cp1 between the second island-shaped portion Ip12 and the third island-shaped portion Ip13 connects the approximately central portions in the +X direction, which is the third direction, of both the second island-shaped portion Ip12 and the third island-shaped portion Ip13. The connecting portion Cp1 between the third island-shaped portion Ip13 and the fourth island-shaped portion Ip14 connects the approximately central portions in the +X direction, which is the third direction, of both the third island-shaped portion Ip13 and the fourth island-shaped portion Ip14. The connecting portion Cp1 between the fourth island-shaped portion Ip14 and the fifth island-shaped portion Ip15 connects the approximately central portions of the fourth island-shaped portion Ip14 and the fifth island-shaped portion Ip15 in the +X direction, which is the third direction of each. The connecting portion Cp1 between the fifth island-shaped portion Ip15 and the sixth island-shaped portion Ip16 connects the approximately central portions of the fifth island-shaped portion Ip15 and the sixth island-shaped portion Ip16 in the +X direction, which is the third direction of each. The connecting portion Cp1 between the sixth island-shaped portion Ip16 and the seventh island-shaped portion Ip17 connects the approximately central portions of the sixth island-shaped portion Ip16 and the seventh island-shaped portion Ip17 in the +X direction, which is the third direction of each.

[0058] Here, the second region A2 may include, for example, multiple connecting portions Cp1. More specifically, in one busbar portion 311b, the second region A2 may include all of the connecting portions Cp1.

[0059] Furthermore, for example, the busbar portion 311b includes a first protruding portion Dp1 and a second protruding portion Dp2. The first protruding portion Dp1 is a portion that protrudes in the -Y direction as the first direction from the seventh island portion Ip17, which is the island portion Ip1 located furthest towards the first end E1 among the multiple island portions Ip1 in one busbar portion 311b. The second protruding portion Dp2 is a portion that protrudes in the +Y direction as the second direction from the first island portion Ip11, which is the island portion Ip11 located furthest towards the second end E2 among the multiple island portions Ip1 in one busbar portion 311b. In the example in Figure 4, the first protruding portion Dp1 protrudes in the -Y direction as the first direction from the approximately central portion in the +X direction as the third direction of the seventh island portion Ip17. The second protruding portion Dp2 protrudes in the second direction (+Y) from approximately the central portion of the first island-shaped portion Ip11 in the third direction (+X). Here, for example, the busbar portion 311b does not have to include the first protruding portion Dp1, nor does it have to include the second protruding portion Dp2.

[0060] <<Structure of the finger section>> As shown in Figure 4, the multiple finger portions 311f are arranged at a predetermined pitch in the -Y direction, which is the first direction. The predetermined pitch is, for example, about 0.8 mm to 2 mm. Here, for example, the distance between two adjacent finger portions 311f may be slightly deviated from the predetermined pitch.

[0061] As shown in Figure 4, the multiple finger sections 311f include multiple first finger sections 311f1 and multiple second finger sections 311f2. Each of the multiple first finger sections 311f1 is connected to the first region A1 of the busbar section 311b. Each of the multiple second finger sections 311f2 is connected to the second region A2 of the busbar section 311b.

[0062] 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, each of the plurality of first finger portions 311f1 is connected to the seventh island portion Ip17, which is the island portion Ip1 located furthest to the first end E1 among the plurality of island portions Ip1 in one busbar portion 311b. In addition, each of the plurality of second finger portions 311f2 is connected to an island portion Ip1 different from the seventh island portion Ip17 among the plurality of island portions Ip1 in one busbar portion 311b.

[0063] Each of the multiple first finger portions 311f1 includes a portion P1 connected to the first region A1 (also called the first portion or first connection portion) and a portion P2 separated from the first region A1 (also called the second portion or first thin wire portion). Here, the fact that the second portion P2 is separated from the first region A1 can be rephrased as the fact that the second portion P2 is not physically connected to the first region A1. In other words, the second portion P2 is not directly connected to the first region A1. Alternatively, the fact that the second portion P2 is separated from the first region A1 can be rephrased as the fact that the second portion P2 is electrically connected to the first region A1 via the first portion P1. In other words, the second portion P2 is electrically connected to the first region A1 via the first portion P1. The length (also called the width) of the first portion P1 in the -Y direction as the first direction is greater than the length (also called the width) of the second portion P2 in the -Y direction as the first direction. For example, when manufacturing a solar cell module 100, even if the first wiring material 32 joined to the first region A1 of the busbar portion 311b applies force to the first region A1, the occurrence of disconnection in the first portion P1 of the multiple first finger portions 311f1 connected to the first region A1 can be reduced. As a result, the durability of the solar cell element 31 and the solar cell module 100 can be improved, thereby improving reliability.

[0064] Here, the width of the second part (first thin wire section) P2 is, for example, about 10 μm to 100 μm. The width of the first part (first connecting section) P1 is, for example, about 1.05 to 10 times the width of the second part (first thin wire section) P2. The length of the first part (first connecting section) P1 in the third direction, the +X direction, is, for example, about 0.1 mm to 3 mm.

[0065] For example, the first portion P1 is connected to the seventh island portion Ip17, which is the island portion Ip1 located furthest to the first end E1 among a plurality of island portions Ip1 in one busbar portion 311b. More specifically, for example, each first finger portion 311f1 is connected to the side in the +X direction as a third direction and the side in the -X direction as a fourth direction in the seventh island portion Ip17. And, for example, each first finger portion 311f1 includes two first portions P1, each connected to the side in the +X direction as a third direction and the side in the -X direction as a fourth direction in the seventh island portion Ip17. More specifically, for example, each first finger portion 311f1 includes one first portion P1 connected to the side of the seventh island portion Ip17 in the +X direction as the third direction, and another first portion P1 connected to the side of the seventh island portion Ip17 in the -X direction as the fourth direction. Also, for example, the second portion P2 is separated from the seventh island portion Ip17, which is the island portion Ip1 located furthest to the first end E1 among the multiple island portions Ip1 in one busbar portion 311b. In each first finger portion 311f1, the second portion P2 is, for example, a different portion from the first portion P1.

[0066] Each of the multiple second finger portions 311f2 includes a portion P3 connected to the second region A2 (also called the third portion or second connection portion) and a portion P4 separated from the second region A2 (also called the fourth portion or second thin wire portion). Here, the fact that the fourth portion P4 is separated from the second region A2 can be rephrased as the fact that the fourth portion P4 is not physically connected to the second region A1. In other words, the fourth portion P4 is not directly connected to the second region A2. Alternatively, the fact that the fourth portion P4 is separated from the second region A2 can be rephrased as the fact that the fourth portion P4 is electrically connected to the second region A2 via the third portion P3. In other words, the fourth portion P4 is electrically connected to the second region A2 via the third portion P3. The length (also called the width) of the third portion P3 in the first direction (-Y direction) is greater than or equal to the length (also called the width) of the fourth portion P4 in the first direction (-Y 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 the first finger portion 311f1, which is a part of the multiple finger portions 311f, is selectively increased. As a result, compared to a configuration in which the widths of all finger portions 311f are equally large, or a configuration in which all finger portions 311f have the same structure as the first finger portion 311f1, the amount of sunlight that is blocked from entering the semiconductor substrate 310 by the multiple second finger 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 increased. In addition, the amount of material required to form the multiple finger portions 311f can be reduced. From another perspective, for example, the width of the first portion P1 of the first finger portion 311f1 is larger than the width of the third portion P3 of the second finger portion 311f2. As a result, for example, when manufacturing a solar cell module 100, even if the first wiring material 32 joined to the busbar portion 311b applies force to the busbar portion 311b, the occurrence of disconnection in the first portion P1 connected to the first region A1 of the multiple first finger portions 311f1 can be reduced. As a result, the durability of the solar cell element 31 and the solar cell module 100 can be improved, thereby improving reliability.Therefore, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved.

[0067] Here, the width of the fourth section (second thin wire section) P4 may be the same as, for example, the width of the second section (first thin wire section) P2, or it may be different from the width of the second section (first thin wire section) P2. The width of the fourth section (second thin wire section) P4 is, for example, about 10 μm to 100 μm. The width of the third section (second connecting section) P3 is, for example, about 1 to 10 times the width of the fourth section (second thin wire section) P4. The length of the third section (second connecting section) P3 in the +X direction as the third direction is, for example, about 0.1 mm to 3 mm. Here, for example, if the width of the third portion P3 is greater than the width of the fourth portion P4, then when the solar cell module 100 is manufactured, even if the first wiring material 32 joined to the second region A2 of the busbar portion 311b applies force to the second region A2, the occurrence of disconnection in the third portion P3, which is the portion of the multiple second finger portions 311f2 connected to the second region A2, can be reduced.

[0068] For example, the third portion P3 is connected to an island portion Ip1 that is different from the seventh island portion Ip17 among the multiple island portions Ip1 in one busbar portion 311b. More specifically, for example, each second finger portion 311f2 is connected to the side in the +X direction as a third direction and the side in the -X direction as a fourth direction in an island portion Ip1 that is different from the seventh island portion Ip17 among the multiple island portions Ip1 in one busbar portion 311b. And, for example, each second finger portion 311f2 includes two third portions P3 that are connected to the side in the +X direction as a third direction and the side in the -X direction as a fourth direction in an island portion Ip1 that is different from the seventh island portion Ip17 among the multiple island portions Ip1. More specifically, for example, each second finger portion 311f2 includes one third portion P3 connected to the +X direction side as a third direction in an island portion Ip1 different from the seventh island portion Ip17, and another third portion P3 connected to the -X direction side as a fourth direction in an island portion Ip1 different from the seventh island portion Ip17. Also, for example, the fourth portion P4 is separated from the island portion Ip1 that is different from the seventh island portion Ip17 among the multiple island portions Ip1. In each second finger portion 311f2, the fourth portion P4 is, for example, a portion different from the third portion P3.

[0069] Furthermore, as shown in Figure 4, for example, the multiple finger portions 311f include a third finger portion 311f3. More specifically, the multiple finger portions 311f include a multiple third finger portion 311f3. The third finger portion 311f3 is connected to the connecting portion Cp1. More specifically, each of the multiple third finger portions 311f3 is connected to the connecting portion Cp1. The third finger portion 311f3 includes a portion P5 connected to the connecting portion Cp1 (also called the fifth portion or third connecting portion) and a portion P6 separated from the connecting portion Cp1 (also called the sixth portion or third thin wire portion). Here, the fact that the sixth portion P6 is separated from the connecting portion Cp1 can be rephrased as the fact that the sixth portion P6 is not physically connected to the connecting portion Cp1. In other words, the sixth portion P6 is not directly connected to the connecting portion Cp1. Furthermore, the fact that the sixth portion P6 is separated from the connecting portion Cp1 can be rephrased 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, each of the multiple third finger portions 311f3 includes a fifth portion (third connecting portion) P5 connected to the connecting portion Cp1 and a sixth portion (third thin wire portion) P6 separated from the connecting portion Cp1. The length (also called the width) of the fifth portion P5 in the -Y direction as the first direction is greater than or equal to the length (also called 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 that is blocked from entering the semiconductor substrate 310 by the multiple third finger portions 311f3 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 increased.

[0070] Here, the width of the sixth section (third thin wire section) P6 may be the same as, for example, the width of the fourth section (second thin wire section) P4, or it may be different from the width of the fourth section (second thin wire section) P4. The width of the sixth section (third thin wire section) P6 is, for example, about 10 μm to 100 μm. The width of the fifth section (third connecting section) P5 is, for example, about 1 to 10 times the width of the sixth section (third thin wire section) P6. The length of the fifth section (third connecting section) P5 in the +X direction as the third direction is, for example, about 0.1 mm to 3 mm. Here, for example, if the width of the fifth portion P5 is greater than the width of the sixth portion P6, then when the solar cell module 100 is manufactured, even if the first wiring material 32 joined to the connecting portion Cp1 of the busbar portion 311b applies force to the connecting portion Cp1, the occurrence of disconnection in the fifth portion P5 connected to the connecting portion Cp1 of the multiple third finger portions 311f3 can be reduced.

[0071] Furthermore, for example, each third finger portion 311f3 is connected to the side in the +X direction as the third direction and the side in the -X direction as the fourth direction of the connecting portion Cp1. And, for example, each third finger portion 311f3 includes two fifth portions P5 connected to the side in the +X direction as the third direction and the side in the -X direction as the fourth direction of the connecting portion Cp1. More specifically, for example, each third finger portion 311f3 includes one fifth portion P5 connected to the side in the +X direction as the third direction of the connecting portion Cp1 and one fifth portion P5 connected to the side in the -X direction as the fourth direction of the connecting portion Cp1. In other words, for example, the third finger portion 311f3 includes two fifth portions P5 connected to the side in the +X direction as the third direction and the side in the -X direction as the fourth direction of the connecting portion Cp1, and a sixth portion P6 that is detached from the connecting portion Cp1. The +X direction as the third direction intersects with the -Y direction as the first direction and is a direction along the first surface 310a. In each third finger portion 311f3, the sixth portion P6 is, for example, a different portion from the fifth portion P5. Here, for example, two fifth portions P5 have an end (also called the fifth end) E5 located in the -X direction as the fourth direction, opposite to the +X direction as the third direction, and an end (also called the sixth end) E6 located in the +X direction as the third direction. In other words, for example, of the two fifth portions P5 connected to the side of the connecting portion Cp1 in the +X direction as the third direction and the side in the -X direction as the fourth direction, the fifth portion P5 located in the -X direction as the fourth direction from the connecting portion Cp1 has a fifth end E5 as the end opposite to the connecting portion Cp1. For example, of the two fifth parts P5 connected to the +X side (a third direction) and the -X side (a fourth direction) of the connecting part Cp1, the fifth part P5 located in the +X direction (a third direction) more than the connecting part Cp1 has a sixth end E6 as the end opposite to the connecting part Cp1.

[0072] Here, for example, if the second region A2 includes a plurality of connecting portions Cp1, then the plurality of second finger portions 311f2 include a plurality of third finger portions 311f3.

[0073] Furthermore, as shown in Figure 4, for example, the multiple finger portions 311f include a fourth finger portion 311f4 and a fifth finger portion 311f5.

[0074] The fourth finger portion 311f4 is connected to the first protruding portion Dp1. The fourth finger portion 311f4 includes a portion P7 connected to the first protruding portion Dp1 (also called the seventh portion or the fourth connection portion) and a portion P8 separated from the first protruding portion Dp1 (also called the eighth portion or the fourth thin wire portion). Here, the fact that the eighth portion P8 is separated from the first protruding portion Dp1 can be rephrased as the fact that the eighth portion P8 is not 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. Alternatively, the fact that the eighth portion P8 is separated from the first protruding portion Dp1 can be rephrased 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 called the width) of the seventh portion P7 in the first direction, the -Y direction, is greater than or equal to the length (also called the width) of the eighth portion P8 in the first direction, the -Y 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 that is blocked from entering the semiconductor substrate 310 by the multiple 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 increased.

[0075] Here, the width of the eighth section (fourth thin wire section) P8 may be the same as, for example, the width of the fourth section (second thin wire section) P4, or it may be different from the width of the fourth section (second thin wire section) P4. The width of the eighth section (fourth thin wire section) P8 is, for example, about 10 μm to 100 μm. The width of the seventh section (fourth connecting section) P7 is, for example, about 1 to 10 times the width of the eighth section (fourth thin wire section) P8. The length of the seventh section (fourth connecting section) P7 in the third direction, the +X direction, is, for example, about 0.1 mm to 3 mm.

[0076] Furthermore, for example, the fourth finger portion 311f4 is connected to the side of the first protruding portion Dp1 in the +X direction as the third direction and to the side of the first protruding portion Dp1 in the -X direction as the fourth direction. And, for example, the fourth finger portion 311f4 includes two seventh portions P7 connected to the side of the first protruding portion Dp1 in the +X direction as the third direction and to the side of the first protruding portion Dp1 in the -X direction as the fourth direction. More specifically, for example, each fourth finger portion 311f4 includes one seventh portion P7 connected to the side of the first protruding portion Dp1 in the +X direction as the third direction and one seventh portion P7 connected to the side of the first protruding portion Dp1 in the -X direction as the fourth direction. In the fourth finger portion 311f4, the eighth portion P8 is, for example, a portion different from the seventh portion P7.

[0077] The fifth finger portion 311f5 is connected to the second protruding portion Dp2. The fifth finger portion 311f5 includes a portion P9 connected to the second protruding portion Dp2 (also called the ninth portion or the fifth connection portion) and a portion P10 that is separated from the second protruding portion Dp2 (also called the tenth portion or the fifth thin wire portion). Here, the fact that the tenth portion P10 is separated from the second protruding portion Dp2 can be rephrased as the fact that the tenth portion P10 is not 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. Alternatively, the fact that the tenth portion P10 is separated from the second protruding portion Dp2 can be rephrased 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 called the width) of the ninth portion P9 in the first direction, the -Y direction, is greater than or equal to the length (also called the width) of the tenth portion P10 in the first direction, the -Y 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 that is blocked from entering the semiconductor substrate 310 by the multiple fifth finger portions 311f5 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 increased.

[0078] Here, the width of the 10th section (5th thin wire section) P10 may be the same as, for example, the width of the 4th section (2nd thin wire section) P4, or it may be different from the width of the 4th section (2nd thin wire section) P4. The width of the 10th section (5th thin wire section) P10 is, for example, about 10 μm to 100 μm. The width of the 9th section (5th connecting section) P9 is, for example, about 1 to 10 times the width of the 10th section (5th thin wire section) P10. The length of the 9th section (5th connecting section) P9 in the +X direction as the third direction is, for example, about 0.1 mm to 3 mm. Here, for example, if the width of the ninth portion P9 is greater than the width of the tenth portion P10, then when the solar cell module 100 is manufactured, even if the first wiring material 32 joined to the second protruding portion Dp2 of the busbar portion 311b applies force to the second protruding portion Dp2, the occurrence of disconnection in the ninth portion P9, which is the part of the fifth finger portion 311f5 connected to the second protruding portion Dp2, can be reduced.

[0079] Furthermore, for example, the fifth finger portion 311f5 is connected to the side of the second protruding portion Dp2 in the +X direction as the third direction and the side of the second protruding portion Dp2 in the -X direction as the fourth direction. And, for example, the fifth finger portion 311f5 includes two ninth portions P9 connected to the side of the second protruding portion Dp2 in the +X direction as the third direction and the side of the second protruding portion Dp2 in the -X direction as the fourth direction. More specifically, for example, each fifth finger portion 311f5 includes one ninth portion P9 connected to the side of the second protruding portion Dp2 in the +X direction as the third direction and one ninth portion P9 connected to the side of the second protruding portion Dp2 in the -X direction as the fourth direction. In the fifth finger portion 311f5, the tenth portion P10 is, for example, a portion different from the ninth portion P9.

[0080] Here, for example, if the busbar portion 311b does not include the first protruding portion Dp1, the multiple finger portions 311f do not need to include the fourth finger portion 311f4. Also, for example, if the busbar portion 311b does not include the second protruding portion Dp2, the multiple finger portions 311f do not need to include the fifth finger portion 311f5.

[0081] <1-2. Solar Cell Modules> A solar cell module 100 according to the first embodiment will be described with reference to Figures 5 to 7. The solar cell module 100 according to the first embodiment is manufactured, for example, using the solar cell element 31 according to the first embodiment described above.

[0082] As shown in Figures 5 and 6, the solar cell module 100 includes, for example, a power generation element 10. The power generation element 10 has, for example, a surface 10f to which light is mainly incident (also called the front surface or light-receiving surface) and a surface 10b located on the opposite side of this front surface 10f (also called the back surface).

[0083] For example, the front surface 10f is facing the +Z direction. For example, the back surface 10b is facing the -Z direction. When the solar cell module 100 is used for power generation outdoors, the +Z direction is set to face, for example, the sun at its highest point in the sky. In the example in Figure 5, the front surface 10f has a rectangular shape as an example of a rectangular shape.

[0084] The solar cell module 100 may further include, for example, a terminal box J1 for extracting power generated in 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 located, for example, along the outer periphery of the power generator 10. In this case, for example, a low-moisture-permeability sealing material such as a butyl resin may be filled between the outer periphery of the power generator 10 and the frame 6.

[0085] As shown in Figures 5 and 6, for example, the power generation unit 10 comprises a solar cell unit 3 and a sealing material 4. Furthermore, for example, the power generation unit 10 comprises a first protective member 1 and a second protective member 2.

[0086] <1-2-1. First protective member> The first protective member 1 is, for example, a member for protecting the solar cell unit 3 from the front surface 10f side. The first protective member 1 is, for example, in a state where it constitutes the front surface 10f of the power generation unit 10. The first protective member 1 is, for example, light-transmitting. Specifically, the first protective member 1 is, for example, light-transmitting to light of a specific range of wavelengths. The specific range of wavelengths includes, for example, the wavelengths of light that the solar cell unit 3 can photoelectrically convert. If the specific range of wavelengths includes wavelengths of light with high irradiation intensity from sunlight, the photoelectric conversion efficiency of the solar cell module 100 can be improved. As shown in Figure 6, 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 where it constitutes the front surface 10f of the power generation unit 10. The first surface 1f is the surface opposite to the solar cell unit 3. The second surface 1s is the surface of the first protective member 1 opposite to the first surface 1f. The second surface 1s faces the solar cell unit 3. In the examples shown in Figures 5 and 6, 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 may be, for example, a flat plate or a sheet. The material for the flat plate may be, for example, glass or a resin such as polycarbonate. The material for the sheet may be, for example, a weather-resistant fluorine-based resin. Weather-resistant fluorine-based resins include, for example, fluorinated ethylene propylene copolymer (FEP), ethylene tetrafluoroethylene copolymer (ETFE), and / or ethylene chlorotrifluoroethylene copolymer (ECTFE).

[0087] <1-2-2. Second protective component> The second protective member 2 is, for example, a member for protecting the solar cell portion 3 from the back surface 10b side. The second protective member 2 is, for example, in a state where it constitutes the back surface 10b of the power generation unit 10. The second protective member 2 may or may not be light-transmitting. As shown in Figure 6, 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 where it constitutes the back surface 10b of the power generation unit 10. The fourth surface 2s is the surface opposite to the solar cell portion 3. The third surface 2f is the surface of the second protective member 2 opposite to the fourth surface 2s. The third surface 2f faces the solar cell portion 3. In the examples of Figures 5 and 6, the third surface 2f and the fourth surface 2s each have a rectangular shape as an example of a rectangle. For example, a sheet-like or flat plate-like member can be applied to the second protective member 2. For example, a backsheet that constitutes the back surface 10b can be applied to the sheet-like member. For the back sheet material, for example, resin may be used. For the flat plate-shaped components, for example, glass plates or polycarbonate plates may be used.

[0088] <1-2-3. Solar cell section> The solar cell unit 3 is located, for example, between the first protective member 1 and the second protective member 2. In other words, the solar cell unit 3 is facing both the first protective member 1 and the second protective member 2 in the Z direction.

[0089] As shown in Figures 5 and 6, the solar cell unit 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. In other words, the plurality of solar cell elements 31 are located facing the second surface 1s of the first protective member 1. Furthermore, the plurality of solar cell elements 31 are aligned along the second surface 1s of the first protective member 1. In other words, the plurality of solar cell elements 31 are arranged planarly along the second surface 1s of the first protective member 1. In the example of Figures 5 and 6, the plurality of solar cell elements 31 are located in a two-dimensional arrangement along a virtual XY plane.

[0090] More specifically, for example, in each of the multiple 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. In the example in Figure 6, the first element surface F1 is facing in the +Z direction, and the second element surface F2 is facing in the -Z direction.

[0091] The solar cell unit 3 includes, for example, a first wiring material 32. The solar cell unit 3 also includes, for example, a second wiring material 33. In the examples of Figures 5 and 6, the solar cell unit 3 includes a plurality of first wiring materials 32 and a plurality of second wiring materials 33.

[0092] The solar cell unit 3 includes, for example, a plurality of solar cell strings 30. The plurality of solar cell strings 30 are arranged, for example, in the +X direction as a third direction. In the examples of Figures 5 and 6, the solar cell unit 3 includes four solar cell strings 30 as the plurality of solar cell strings 30. More specifically, as shown in Figure 5, 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 a third direction in the order described herein.

[0093] In the examples shown in Figures 5 and 6, the first solar cell string 30a and the third solar cell string 30c have substantially identical configurations, and the second solar cell string 30b and the fourth solar cell string 30d have substantially identical configurations. Furthermore, the configurations of two adjacent solar cell strings 30 in the third direction, the +X direction, have substantially twofold rotational symmetry, meaning that when rotated 180 degrees around a symmetry axis parallel to the Z-axis, they have substantially identical configurations. For example, the first solar cell string 30a and the second solar cell string 30b have substantially twofold rotational symmetry, meaning that when rotated 180 degrees around a symmetry axis parallel to the Z-axis, they have substantially twofold rotational symmetry, meaning that when rotated 180 degrees around a symmetry axis parallel to the Z-axis, they have substantially twofold rotational symmetry, meaning that when rotated 180 degrees around a symmetry axis parallel to the Z-axis, they have substantially twofold rotational symmetry, meaning that when rotated 180 degrees around a symmetry axis parallel to the Z-axis, they have substantially identical configurations. The third solar cell string 30c and the fourth solar cell string 30d have a substantially twofold rotational symmetry relationship, meaning that when rotated 180 degrees around an axis of symmetry parallel to the Z-axis, they have almost identical configurations. In other words, although not strictly accurate, the second solar cell string 30b and the fourth solar cell string 30d can be considered to have configurations based on the first solar cell string 30a and the third solar cell string 30c, respectively, with the first direction changed from the -Y direction to the +Y direction and the second direction changed from the +Y direction to the -Y direction. In the following, to avoid complicating the explanation, the configuration of the first solar cell string 30a will sometimes be described as a representative example when describing the configuration of the solar cell strings 30.

[0094] Each of the multiple solar cell strings 30 includes, for example, two or more solar cell elements 31 and multiple first wiring materials 32. In each solar cell string 30, the two or more solar cell elements 31 are aligned, for example, in the +Y direction as a second direction. In the example of Figures 5 and 6, each solar cell string 30 includes six solar cell elements 31 that are separated in the -Y direction as a first direction, as two or more solar cell elements 31. More specifically, as shown in Figures 5 and 6, 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 aligned in the +Y direction as a second direction, in the order described herein. In other words, the first solar cell element 31a and the second solar cell element 31b are separated in the first direction, the -Y direction, and aligned in the second direction, the +Y direction. The second solar cell element 31b and the third solar cell element 31c are separated in the first direction, the -Y direction, and aligned in the second direction, the +Y direction. The third solar cell element 31c and the fourth solar cell element 31d are separated in the first direction, the -Y direction, and aligned in the second direction, the +Y direction. The fourth solar cell element 31d and the fifth solar cell element 31e are separated in the first direction, the -Y direction, and aligned in the second direction, the +Y direction. The fifth solar cell element 31e and the sixth solar cell element 31f are separated in the first direction, the -Y direction, and aligned in the second direction, the +Y direction.

[0095] Multiple first wiring materials 32 electrically connect two adjacent solar cell elements 31 from 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 material 32 connects the second output section 312b on the second element surface F2 of one solar cell element 31 to the busbar section 311b on the first element surface F1 of another solar cell element 31 that is adjacent to this solar cell element 31 in the first direction, the -Y direction. Also, for example, in the second solar cell string 30b and the fourth solar cell string 30d, the first wiring material 32 connects the second output section 312b on the second element surface F2 of one solar cell element 31 to the busbar section 311b on the first element surface F1 of another solar cell element 31 that is adjacent to this solar cell element 31 in the second direction, the +Y direction.

[0096] In the examples of Figures 5 and 6, each of the five first wiring materials 32, which constitute a plurality of first wiring materials 32, is electrically connected to the first solar cell element 31a and the second solar cell element 31b. Here, for example, each first wiring material 32 includes a portion joined to the first solar cell element 31a and a portion joined to the second solar cell element 31b. Each of the five first wiring materials 32, which constitute a plurality of first wiring materials 32, is electrically connected to the second solar cell element 31b and the third solar cell element 31c. Here, for example, each first wiring material 32 includes a portion joined to the second solar cell element 31b and a portion joined to the third solar cell element 31c. Each of the five first wiring materials 32, which constitute a plurality of first wiring materials 32, is electrically connected to the third solar cell element 31c and the fourth solar cell element 31d. Here, for example, each first wiring material 32 includes a portion joined to the third solar cell element 31c and a portion joined to the fourth solar cell element 31d. Each of the five first wiring materials 32, as a plurality of first wiring materials 32, is in a state where it electrically connects the fourth solar cell element 31d and the fifth solar cell element 31e. Here, for example, each first wiring material 32 includes a portion joined to the fourth solar cell element 31d and a portion joined to the fifth solar cell element 31e. Each of the five first wiring materials 32, as a plurality of first wiring materials 32, is in a state where it electrically connects the fifth solar cell element 31e and the sixth solar cell element 31f. Here, for example, each first wiring material 32 includes a portion joined to the fifth solar cell element 31e and a portion joined to the sixth solar cell element 31f.

[0097] Each of the multiple second wiring materials 33 electrically connects two adjacent solar cell strings 30 among the multiple solar cell strings 30. In the example in Figure 5, 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.

[0098] The power generator 10 further includes, for example, two third wiring members 34. Each of the two third wiring members 34 is connected to the solar cell unit 3 to output power from the solar cell unit 3. In the example of Figure 5, the first third wiring member 34 is electrically connected to the first solar cell string 30a located at the far end in the -X direction. The second third wiring member 34 is electrically connected to the fourth solar cell string 30d located at the far end in the +X direction. Each of the two third wiring members 34 has, for example, a portion that is drawn out to the outside of the power generator 10. For example, each of the two third wiring members 34 is located in a state where it is drawn out to the outside of the power generator 10 through a hole that penetrates the second protective member 2.

[0099] Here, for example, the number of solar cell strings 30 included in the solar cell unit 3 is not limited to multiple. The solar cell unit 3 may include one solar cell string 30, or it may include any number of solar cell strings 30, two or more. In other words, the solar cell unit 3 may include one or more solar cell strings 30. For example, if the solar cell unit 3 includes one solar cell string 30, the solar cell unit 3 does not need to include the second wiring material 33. Also, for example, the solar cell string 30 may include two or more solar cell elements 31, such as two solar cell elements 31, or it may include any number of solar cell elements 31, three or more. Here, for example, a configuration 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 can be adopted. In other words, for example, a configuration in which the solar cell unit 3 includes a first solar cell element 31a, a second solar cell element 31b, and a first wiring material 32 can be adopted.

[0100] <1-2-4. Sealing Material> The sealing material 4 is, for example, covering the solar cell section 3. For example, the sealing material 4 is in contact with the second surface 1s and the third surface 2f. In other words, the sealing material 4 is, for example, positioned in a state where it fills the area between the first protective member 1 and the second protective member 2, and is 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 called the first sealing material) 41 located on the front surface 10f side and a sealing material (also called the second sealing material) 42 located on the back surface 10b side. The first sealing material 41 is, for example, covering the entire surface of the solar cell section 3 on the side of the first protective member 1. In other words, the first sealing material 41 is, for example, 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, covering the entire surface of the solar cell section 3 on the side of the second protective member 2. In other words, the second sealing material 42 is, for example, positioned between the second protective member 2 and the solar cell unit 3, covering the solar cell unit 3. As a result, the solar cell unit 3 is sandwiched and surrounded by, for example, the first sealing material 41 and the second sealing material 42. This allows, for example, the sealing material 4 to maintain the orientation of the solar cell unit 3.

[0101] Furthermore, the encapsulant 4 is, for example, light-transmitting. Here, the encapsulant 4 is, for example, light-transmitting to light of a specific range of wavelengths as described above. For example, if at least the first encapsulant 41 of the first encapsulant 41 and second encapsulant 42 constituting the encapsulant 4 is light-transmitting, incident light from the front surface 10f can reach the solar cell section 3. For example, resin is applied to the materials of the first encapsulant 41 and the second encapsulant 42. More specifically, the material of the first encapsulant 41 is, for example, ethylene vinyl acetate copolymer (EVA). Polyvinyl acetal such as polyvinyl butyral (PVB), or polyolefin elastomer (POE) can be used. For example, if a relatively inexpensive material such as EVA is used for the first encapsulant 41, the ability to protect multiple solar cell elements 31 can be easily achieved.

[0102] Furthermore, the material of the second encapsulant 42 may be, for example, polyvinyl acetal such as EVA or PVB, or POE, similar to the first encapsulant 41. Each of the first encapsulant 41 and the second encapsulant 42 may be composed of, for example, two or more different materials.

[0103] Furthermore, the power generation unit 10 may further include a packing portion (not shown) located along an annular portion of the region between the first protective member 1 and the second protective member 2 that is open to the external space. In this case, the packing portion is located, for example, surrounding the outer periphery of the region between the first protective member 1 and the second protective member 2 that includes the solar cell portion 3 and the sealing material 4. Here, the packing portion is located in a form that fills the region from the first protective member 1 to the second protective member 2. Here, for example, if the packing portion has a lower moisture permeability than the sealing material 4, the packing portion can seal the portion along the outer periphery of the region between the first protective member 1 and the second protective member 2. As a result, the packing portion can reduce the intrusion of moisture and other substances from the outside of the solar cell module 100 towards the solar cell portion 3. For example, the material of the packing portion may be a butyl resin, a polyisopropylene resin, or an acrylic resin. The material of the packing portion may include metals such as copper or solder, or nonmetals such as glass, as long as it has low moisture permeability.

[0104] <1-2-5. Electrical connection between two adjacent solar cell elements> The first wiring material 32 electrically connects, for example, the busbar portion 311b, which serves as a first output portion, on the first element surface F1 of one solar cell element 31, to the second output portion 312b, which is on the second element surface F2 of another solar cell element 31 adjacent to this solar cell element 31 in a first or second direction. Specifically, in the examples of Figures 1 and 2, the outer edges of the multiple first wiring materials 32 joined to each of the solar cell elements 31 are virtually depicted as thin dashed lines. In the examples of Figures 1, 2, and 5 to 7, the first wiring material 32 has an elongated shape along the -Y direction, which is the first direction. Here, the first wiring material 32 is joined, for example, to the busbar portion 311b of one solar cell element 31 and to the second output portion 312b of another solar cell element 31 adjacent to this solar cell element 31. Here, for example, there is a portion 321 (also called the first joining portion) between the first wiring material 32 and the busbar portion 311b that connects the first wiring material 32 and the busbar portion 311b. Therefore, for example, the first wiring material 32 is joined to the busbar portion 311b of one solar cell element 31 via the first joining portion 321. Also, for example, there is a portion 322 (also called the second joining portion) between the first wiring material 32 and the second output portion 312b. Therefore, for example, the first wiring material 32 is joined to the second output portion 312b of another solar cell element 31 adjacent to one solar cell element 31 via the second joining portion 322.

[0105] The first wiring material 32 may be, for example, a linear or strip-shaped conductive metal body. The cross-sectional shape of the first wiring material 32 perpendicular to the longitudinal direction may be, for example, a polygonal shape such as a rectangle, triangle, or trapezoid, or a curved shape such as a circle or ellipse, or a shape that combines a polygonal shape and a curved shape. The width W2 of the first wiring material 32 may be, for example, 0.2 mm to 1.5 mm. The thickness of the first wiring material 32 may be, for example, 0.1 mm to 1.5 mm. The width W2 of the first wiring material 32 may be, for example, the length in the direction perpendicular to the longitudinal direction (also called the width direction) of the first wiring material 32 when the first element surface F1 of the solar cell element 31 is viewed from above. The longitudinal direction of the first wiring material 32 may be, for example, the direction along the -Y direction as the first direction. The thickness of the first wiring material 32 may be, for example, the length in the direction perpendicular to both the longitudinal direction and the width direction (also called the thickness direction) of the first wiring material 32. For example, a good conductor such as copper can be used as the conductive metal material applied to the first wiring material 32.

[0106] The materials used for the first joint portion 321 and the second joint portion 322 are, for example, low-melting-point alloys such as solder or low-melting-point elemental metals. For example, a configuration is adopted in which the entire surface of the first wiring material 32 is covered with solder. The first wiring material 32 is electrically connected to the busbar portion 311b and the second output portion 312b, respectively, by soldering. Here, for example, the solder located between the first wiring material 32 and the busbar portion 311b constitutes the first joint portion 321. Also, for example, the solder located between the first wiring material 32 and the second output portion 312b constitutes the second joint portion 322.

[0107] <<Joining the first wiring material to the busbar section>> In the first embodiment, for example, as shown in Figures 1, 2 and 5 to 7, in the first solar cell element 31a, in the -Y direction as the first direction, the second end E2 of the busbar portion 311b is located closer to the second solar cell element 31b than the first end E1 of the busbar 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 busbar portion 311b is located closer to the third solar cell element 31c than the first end E1 of the busbar 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 busbar portion 311b is located closer to the fourth solar cell element 31d than the first end E1 of the busbar 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 busbar portion 311b is located closer to the fifth solar cell element 31e than the first end E1 of the busbar 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 busbar portion 311b is located closer to the sixth solar cell element 31f than the first end E1 of the busbar portion 311b.

[0108] In the state of the solar cell module 100, for example, as shown in Figures 1 and 7, the first wiring material 32 is joined to the busbar portion 311b.

[0109] For example, as shown in Figures 1, 2, 6, and 7, the first wiring material 32 has a third end (also called the third end) E3 and a fourth end (also called the 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. In the examples of Figures 1, 2, 6, and 7, the third end E3 is the end of the first wiring material 32 in the -Y direction as the first direction, and the fourth end E4 is the end of the first wiring material 32 in the +Y direction as the second direction. In other words, for example, the first wiring material 32 has a third end E3 located on the -Y direction side as the first direction on the first element surface F1, and a fourth end E4 located on the +Y direction side as the second direction on the second element surface F2.

[0110] In the first embodiment, for example, in the first wiring material 32 electrically connecting 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 electrically connecting 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 electrically connecting 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 material 32 that electrically connects 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.

[0111] For example, as shown in Figures 1 and 7, the first wiring material 32 is joined to the busbar 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 joined to the busbar 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 joined to the busbar 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 joined to the busbar 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 joined to the busbar 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 joined to the busbar portion 311b along the -Y direction as the first direction.

[0112] Furthermore, as shown in Figure 2, for example, the first wiring material 32 is joined to the second output section 312b along the -Y direction, which is the first direction. More specifically, for example, in the second solar cell element 31b, the first wiring material 32 is joined to the second output section 312b along the -Y direction, which is the first direction. For example, in the third solar cell element 31c, the first wiring material 32 is joined to the second output section 312b along the -Y direction, which is the first direction. For example, in the fourth solar cell element 31d, the first wiring material 32 is joined to the second output section 312b along the -Y direction, which is the first direction. For example, in the fifth solar cell element 31e, the first wiring material 32 is joined to the second output section 312b along the -Y direction, which is the first direction. For example, in the sixth solar cell element 31f, the first wiring material 32 is joined to the second output section 312b along the -Y direction, which is the first direction.

[0113] In the first embodiment, for example, the first wiring material 32 includes a portion on the third end E3 side that is joined to the first end portion Ep1 of the busbar portion 311b. More specifically, for example, the portion of the first wiring material 32 that constitutes the third end E3 is joined to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17).

[0114] <<Mechanism of output characteristic degradation and its operation and effect according to the first embodiment>> Here, let's consider a case where the solar cell module 100 is installed and used outdoors. In this case, for example, during the day, the temperature of the solar cell module 100 rises in response to sunlight irradiation and the power generation by the solar cell module 100 in response to that sunlight irradiation. 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 temperature rise and contraction due to temperature decrease repeatedly occur in each part of the solar cell module 100. Here, due to the difference in thermal expansion coefficients depending on the materials that make up each part of the solar cell module 100, repeated stress application and relaxation can occur within the solar cell module 100.

[0115] For example, consider a case where the material of the first wiring material 32 is copper, the material of the first joint portion 321 joining the first wiring material 32 and the busbar 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 coefficient of thermal expansion of copper is approximately 1.74 × 10⁻⁶. -5 [1 / K], and the instantaneous linear expansion coefficient of solder is approximately 2.35 × 10⁻⁶. -5 [1 / K], and the instantaneous linear expansion coefficient of silver is approximately 1.91 × 10⁻⁶. -5 [1 / K], and the instantaneous coefficient of thermal expansion of silicon is approximately 0.26 × 10⁻⁶. -5 The temperature is [1 / K], where K is Kelvin. Therefore, the first wiring material 32, the first junction portion 321, and the first electrode 311 may expand and contract more significantly in response to temperature changes than the semiconductor substrate 310.

[0116] Here, for example, a first electrode 311 is located on the first surface 310a of the semiconductor substrate 310, and a first wiring material 32 is bonded to the busbar portion 311b of the first electrode 311. In addition, a finger portion 311f, which is thinner than the busbar portion 311b, is connected to the busbar portion 311b of the first electrode 311. Therefore, for example, if a force is applied to the busbar portion 311b due to expansion and contraction in the longitudinal direction of the first wiring material 32, stress concentration may occur in the portion of the finger portion 311f that is connected to the busbar portion 311b.

[0117] For example, when the first wiring material 32 expands, in the portion of the first wiring material 32 located along the busbar portion 311b, excluding the portion near the third end E3, the expansion in the -Y direction (first direction) and the expansion in the +Y direction (second direction) cancel each other out between two or more portions joined to the busbar portion 311b. On the other hand, the portion of the first wiring material 32 located along the busbar portion 311b near the third end E3 is prone to expanding in the -Y direction (first direction), and can apply a force to the busbar portion 311b in the -Y direction (first direction). In this case, for example, if the portion of the first wiring material 32 constituting the third end E3 applies a force to the first end portion Ep1 (e.g., the seventh island-shaped portion Ip17) in the -Y direction (first direction), stress concentration may occur in the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (e.g., the seventh island-shaped portion Ip17).

[0118] For example, when the first wiring material 32 shrinks, in the portion of the first wiring material 32 located along the busbar portion 311b, excluding the portion near the third end E3, the shrinkage in the +Y direction (second direction) and the shrinkage in the -Y direction (first direction) cancel each other out between two or more portions joined to the busbar portion 311b. On the other hand, the portion of the first wiring material 32 located along the busbar portion 311b near the third end E3 is prone to shrinking in the +Y direction (second direction), and can apply a force to the busbar portion 311b in the +Y direction (second direction). In this case, for example, if the portion of the first wiring material 32 constituting the third end E3 applies a force to the first end portion Ep1 (e.g., the seventh island-shaped portion Ip17) in the +Y direction (second direction), stress concentration may occur in the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (e.g., the seventh island-shaped portion Ip17).

[0119] 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 greater than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. Therefore, even if a force is applied to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) by the portion of the first wiring material 32 that constitutes the third end E3, in either the first direction (-Y direction) or the second direction (+Y direction), the stress on the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) may be reduced.

[0120] Furthermore, in solar cell modules 100 installed outdoors, for example, the adhesive strength between the busbar portion 311b and the semiconductor substrate 310 may decrease due to moist heat stress, which is a combination of humidity stress caused by humidity and / or rainfall, and temperature stress caused by temperature.

[0121] Here, for example, consider the case where the first wiring material 32 connecting the busbar 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 busbar portion 311b due to the shrinkage of the first wiring material 32 increases from the second end E2 of the busbar portion 311b of the first solar cell element 31, which is closer to the second solar cell element 31, to the first end E1, which is closer to the third end E3, which is the end (free end) of the first wiring material 32. In this case, the stress generated in the busbar portion 311b is considered to be proportional to the magnitude of the displacement of the busbar portion 311b. Therefore, the stress generated in the busbar portion 311b is thought to be particularly large in the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) located on the first end E1 side, which is close to the third end E3, which is the end (free end) of the first wiring material 32.

[0122] Conversely, let's consider a case where, for example, the first wiring material 32 connecting the busbar 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 busbar portion 311b due to the expansion of the first wiring material 32 increases from the second end E2 of the busbar portion 311b of the first solar cell element 31, which is closer to the second solar cell element 31, to the first end E1, which is closer to the third end E3, which is the end (free end) of the first wiring material 32. In this case, the stress generated in the busbar portion 311b is considered to be proportional to the magnitude of the displacement of the busbar portion 311b. Therefore, the stress generated in the busbar portion 311b is thought to be particularly large in the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) located on the first end E1 side, which is close to the third end E3, which is the end (free end) of the first wiring material 32.

[0123] In these cases, if the adhesive strength between the busbar portion 311b and the semiconductor substrate 310 decreases due to moist heat stress, the busbar portion 311b of the first solar cell element 31 may partially delaminate from the semiconductor substrate 310, starting from the first end E1 side, at the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) located on the first end E1 side. In other words, delamination may occur between the semiconductor substrate 310 and the first electrode 311, starting from the first end E1 side.

[0124] Subsequently, in the solar cell module 100, repeated temperature increases due to sunlight irradiation and power generation during the day, and temperature decreases at night, cause repeated thermal expansion and contraction of the first wiring material 32. As a result, the busbar portion 311b may partially peel off from the semiconductor substrate 310, starting from the first end E1.

[0125] Here, in the portion of the busbar portion 311b that has detached from the semiconductor substrate 310, displacement occurs in response to the displacement caused by thermal expansion and contraction of the first wiring material 32. At this time, since the portion of the busbar portion 311b that has detached from the semiconductor substrate 310 and the first wiring material 32 joined to this portion are not constrained by the semiconductor substrate 310, a larger displacement occurs than when the busbar portion 311b has not detached from the semiconductor substrate 310. This large displacement occurring in the busbar portion 311b generates a larger stress in the first portion P1 of the first finger portion 311f1 to which the busbar portion 311b is connected than when the busbar portion 311b has not detached from the semiconductor substrate 310.

[0126] As a result of the above, for example, the first end portion Ep1 located on the first end E1 side of the busbar portion 311b of the first solar cell element 31 may generate greater stress in the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (e.g., the first island-shaped portion Ip11) after partial delamination from the semiconductor substrate 310 starting from the first end E1 side occurs, compared to before partial delamination from the semiconductor substrate 310 starting from the first end E1 side occurs.

[0127] Furthermore, if such large stresses repeatedly occur in the first portion P1 of the first finger portion 311f1, cracks may develop from the surface of the first portion P1. These cracks may propagate at a rate corresponding to the stress generated in the first portion P1.

[0128] 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. This increases the time until the first portion P1 of the first finger portion 311f1 breaks. As a result, the rate of degradation of the output characteristics caused by temperature rise and fall in the solar cell module 100 can be reduced. In other words, the degree of degradation of the output characteristics of the solar cell module 100 when the same stress is applied can be reduced.

[0129] Based on the above, in the first embodiment, the reliability of the solar cell element 31 and the solar cell module 100 can be improved.

[0130] Here, we will explain with specific examples how to improve the degree of degradation of the output characteristics in the solar cell module 100 according to the first embodiment in response to humid heat stress.

[0131] Here, as three specific examples of the solar cell module 100 according to the first embodiment, the solar cell module of the first example (also simply called the first example), the solar cell module of the second example (also simply called the second example), and the solar cell module of the third example (also simply called the third example) were manufactured. In the first example, the width of the first portion (first connection portion) P1 in each of the first finger portions 311f1 connected to the seventh island-shaped portion Ip17 as the first end portion Ep1 was set to 60 μm. In the second example, the width of the first portion (first connection portion) P1 in each of the first finger portions 311f1 connected to the seventh island-shaped portion Ip17 as the first end portion Ep1 was set to 120 μm. In the third example, the width of the first portion (first connection portion) P1 in each of the first finger portions 311f1 connected to the seventh island-shaped portion Ip17 as the first end portion Ep1 was set to 180 μm. In each of the first, second, and third specific examples, the length of the first portion (first connection portion) P1 in the +X direction as the third direction was set to 1.5 mm, and the width of all finger portions 311f excluding the first portion (first connection portion) P1 was set to 32 μm. Furthermore, the other configurations, excluding the width of the first portion (first connection portion) P1, were the same between the first, second, and third specific examples.

[0132] Furthermore, as a reference example of a solar cell module, a solar cell module of the first reference example (also simply called the first reference example) was fabricated. The first reference example is a solar cell module based on the first, second, and third specific examples, respectively, in which the width of the first portion (first connection portion) P1 in each of the first finger portions 311f1 connected to the seventh island-shaped portion Ip17 as the first end portion Ep1 is changed to 32 μm. In other words, in the first reference example, the width of all finger portions 311f is set to 32 μm.

[0133] As a combined stress test for each solar cell module, a high-temperature and high-humidity test and a temperature cycling 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 1000 hours. In the temperature cycling test, the temperature of the solar cell module was periodically changed between 85°C and -40°C over a period of 6 hours. Two sets of these treatments were performed on the solar cell module.

[0134] Then, for each of the solar cell modules in the first, second, third, and first example examples, the fill factor (FF) was measured before and after a combined stress test to apply moist heat stress.

[0135] Here, the percentage change in FF (curve factor) was calculated for each of the first, second, third, and first reference examples, based on the FF measured before and after the combined stress test. Here, for each of the first, second, third, and first reference examples, the percentage change in FF (in percent (%)) was calculated according to equation (1). In all of the first, second, third, and first reference examples, the FF after the combined stress test was smaller than the FF before the combined stress test, and the percentage change in FF was a negative value.

[0136] The percentage change in FF [%] = {(FF after the combined stress test - FF before the combined stress test) / FF × 100 before the combined stress test (1).

[0137] Furthermore, the rate of change of FF (curve factor) for the first reference example was designated as the first reference rate of change, the rate of change of FF (curve factor) for the first specific example was designated as the first rate of change, the rate of change of FF (curve factor) for the second specific example was designated as the second rate of change, and the rate of change of FF (curve factor) for the third specific example was designated as the third rate of change.

[0138] Table 1 shows the relative rates of change for the first, second, and third specific examples, based on the first reference rate of change.

[0139] Table 1 shows that 0% is the baseline value for the first reference example. Furthermore, the relative rate of change of the FF (curve factor) for the first specific example (also called the first relative rate of change) is shown as +0.4%, which is the value obtained by subtracting the first reference rate of change from the first rate of change. Similarly, the relative rate of change of the FF (curve factor) for the second specific example (also called the second relative rate of change) is shown as +1.9%, which is the value obtained by subtracting the first reference rate of change from the second rate of change. Finally, the relative rate of change of the FF (curve factor) for the third specific example (also called the third relative rate of change) is shown as +2.7%, which is the value obtained by subtracting the first reference rate of change from the third rate of change. In other words, the first, second, and third relative rates of change were calculated according to equations (2), (3), and (4), respectively.

[0140] First relative rate of change = First rate of change - First reference rate of change ... (2) Second relative rate of change = Second rate of change - First reference rate of change ... (3) Third relative rate of change = Third rate of change - First reference rate of change ... (4).

[0141] Table 1 also shows the width of the first part (first connection part) P1 in each of the first reference example, the first specific example, the second specific example, and the third specific example.

[0142] [Table 1]

[0143] As shown in Table 1, compared to the first reference example in which the width of the first part (first connection part) P1 was 32 μm, in the first, second, and third specific examples in which the width of the first part (first connection part) P1 was expanded to 60 μm, 120 μm, and 180 μm, the negative values ​​of the first, second, and third rate of change were closer to zero (0) than the negative value of the first reference rate of change, confirming that the rate of decrease of FF (curve factor) due to the combined cycle test was smaller. More specifically, compared to the first reference example in which the width of the first part (first connection part) P1 was 32 μm, in the first specific example in which the width of the first part (first connection part) P1 was expanded to 60 μm, the negative value of the first rate of change was closer to zero (0) than the negative value of the first reference rate of change, confirming that the rate of decrease of FF (curve factor) due to the combined cycle test was smaller. In the second specific example, where the width of the first part (first connection part) P1 was increased to 120 μm, compared to the first reference example where the width of the first part (first connection part) P1 was 32 μm, the negative value of the second rate of change was closer to zero (0) than the negative value of the first reference rate of change, confirming that the rate of decrease in FF (curve factor) due to the combined cycle test was smaller. In the third specific example, where the width of the first part (first connection part) P1 was increased to 180 μm, compared to the first reference example where the width of the first part (first connection part) P1 was 32 μm, the negative value of the third rate of change was closer to zero (0) than the negative value of the first reference rate of change, confirming that the rate of decrease in FF (curve factor) due to the combined cycle test was smaller. In other words, as in the first embodiment, it was confirmed that increasing the width of the first part (first connection part) P1 reduces the degree of degradation of the output characteristics of the solar cell module 100 when the same stress is applied. In other words, it was estimated that increasing the width of the first portion (first connection portion) P1, as in the first embodiment, could improve the durability of the solar cell element 31 and the solar cell module 100, thereby improving reliability.

[0144] Furthermore, as shown in Table 1, it was confirmed that the larger the width of the first part (first connection part) P1, the larger the positive value of the relative rate of change of FF, the closer the rate of change of FF (which is a negative value) was to zero (0), and the smaller the absolute value of the rate of change of FF. In other words, in the first embodiment, it was confirmed that the larger the width of the first part (first connection part) P1, the less the degree of degradation of the output characteristics of the solar cell module 100 tends to be when the same stress is applied.

[0145] Incidentally, from another perspective, 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 portion 311f2 is smaller than the width of the first portion (first connection portion) P1 of the first finger portion 311f1. In other words, the width of the first portion (first connection portion) P1 of the first finger portion 311f1, which is a part of the multiple finger portions 311f, is selectively made larger. Therefore, compared to, for example, a configuration in which the widths of all finger portions 311f are equally large, or a configuration in which all finger portions 311f have the same structure as the first finger portion 311f1, the amount of sunlight that is blocked from entering the semiconductor substrate 310 by the multiple second finger 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 increased. 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 amount of material required to form the multiple finger portions 311f can be reduced.

[0146] Here, for example, it is conceivable that the first wiring material 32 is joined to the busbar portion 311b with its longitudinal direction 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 of the busbar portion 311b (for example, the seventh island-shaped portion Ip17) is likely to be offset from the center in the width direction of the first end portion Ep1 (for example, the seventh island-shaped portion Ip17). This width direction may be along the +X direction as the third direction. As a result, for example, the portion of the first wiring material 32 near the third end E3 approaches the first finger portion 311f1, and in accordance with the expansion and contraction of the portion of the first wiring material 32 near the third end E3, the force applied from the portion of the first wiring material 32 near the third end E3 to the seventh island-shaped portion Ip17 is more likely to be applied to the first portion P1. Even in this case, for example, if the width of the first part (first connection part) P1 of the first finger part 311f1 is greater than the width of the third part (second connection part) P3 of the second finger part 311f2, it is possible that the stress on the first part P1 will be reduced.

[0147] Furthermore, for example, even if the first end portion Ep1 of the busbar portion 311b partially peels off from the semiconductor substrate 310 due to 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 breaks may be extended. 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 large.

[0148] This reduces the occurrence of disconnections in the first portion P1 connected to the first end portion Ep1 in multiple first finger portions 311f1.

[0149] Incidentally, when manufacturing a solar cell module 100 using the solar cell element 31 according to the first embodiment described above, the portion constituting the third end E3 of the first wiring material 32 can be joined to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17). In this case, as described above, if, for example, the portion constituting the third end E3 of the first wiring material 32 in the solar cell module 100 applies force to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) in either the first direction (-Y direction) or the second direction (+Y direction), stress concentration may occur in the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17).

[0150] 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 part (first connection part) P1 of the first finger part 311f1 connected to the first end part Ep1 (for example, the seventh island-shaped part Ip17) of the busbar part 311b is greater than the width of the third part (second connection part) P3 of the second finger part 311f2. Then, for example, when manufacturing the solar cell module 100 using the solar cell element 31 according to the first embodiment, the part constituting the third end E3 of the first wiring material 32 can be joined to the first end part Ep1 (for example, the seventh island-shaped part Ip17). Therefore, for example, if a force is applied to the portion of the first wiring material 32 that constitutes the third end E3 in the first direction, either in the -Y direction as the first direction or in the +Y direction as the second direction, relative to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17), it is possible that the stress on the first portion P1 of the first finger portion 311f1 connected to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) will be reduced.

[0151] Furthermore, for example, even if the first end portion Ep1 of the busbar portion 311b partially peels off from the semiconductor substrate 310 due to 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 breaks may be extended. 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 large.

[0152] This reduces the occurrence of disconnections in the first portion P1 connected to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) in multiple first finger portions 311f1.

[0153] As a result, the reliability of the solar cell element 31 and the solar cell module 100 can be improved by enhancing their durability.

[0154] From another perspective, 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 third portion (second connection portion) P3 of the second finger portion 311f2 is smaller than the width of the first portion (first connection portion) P1 of the first finger portion 311f1. In other words, the width of the first portion (first connection portion) P1 of the first finger portion 311f1, which is a part of the multiple finger portions 311f, is selectively increased. Therefore, when manufacturing the solar cell module 100 using the solar cell element 31 according to the first embodiment, the amount of sunlight that is blocked from entering the semiconductor substrate 310 by the multiple second finger portions 311f2 can be reduced compared to, for example, a configuration in which the widths of all finger portions 311f are equally large, or a configuration in which all finger portions 311f have the same structure as the first finger portion 311f1. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be increased. 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 amount of material required to form the multiple finger portions 311f can be reduced.

[0155] In other words, assuming that a solar cell module 100 is manufactured using the solar cell element 31 according to the first embodiment, the solar cell element 31 according to the first embodiment has a configuration suitable for improving the power generation efficiency and reliability of both the solar cell element 31 and the solar cell module 100. That is, the solar cell element 31 according to the first embodiment can improve the power generation efficiency and reliability of both the solar cell element 31 and the solar cell module 100. Furthermore, it is possible to reduce the amount of material required to form the multiple finger portions 311f.

[0156] Here, for example, in the third finger portion 311f3 connected to the connecting portion Cp1, the width of the fifth portion P5 may be greater 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 greater than the width W2 of the first wiring material 32. As a result, for example, even if the width W2 of the first wiring material 32 is greater than the width of the connecting portion Cp1, the first wiring material 32 is joined to the fifth portion P5 of the third finger portion 311f3, and the occurrence of joining the first wiring material 32 to the sixth portion P6, which is thinner than the fifth portion P5, can be reduced. For this reason, for example, in the solar cell module 100, even if the first wiring material 32 expands and contracts in response to temperature changes, it is possible that the force applied to the sixth portion (third thin wire portion) P6 by the first wiring material 32 will be reduced.

[0157] As a result, the occurrence of wire breakage in the third finger portion 311f3 can be reduced.

[0158] In other words, the occurrence of wire breakage in the finger portion 311f can be reduced. Therefore, the reliability of the solar cell element 31 and the solar cell module 100 can be improved by increasing their durability.

[0159] Here, for example, if the width W1 of the island-shaped portion Ip1 is greater than the width W2 of the first wiring material 32, the first wiring material 32 can be joined to a position offset from the center of the island-shaped portion Ip1 in the direction along the +X direction (also called the width direction), which is the third direction of the island-shaped portion Ip1. For this reason, for example, when joining the first wiring material 32 to the busbar portion 311b, a displacement of the position of the first wiring material 32 in the direction along the +X direction (the third direction) with respect to the busbar portion 311b, and a slight inclination of the longitudinal direction of the first wiring material 32 with respect to the -Y direction (the first direction) can be permitted.

[0160] <1-3. Manufacturing of Solar Cell Elements> An example of a method for manufacturing a solar cell element 31 will be described with reference to Figures 3 and 8 to 12. For example, a solar cell element 31 can be manufactured by performing the following steps in the order described: preparation of the semiconductor substrate 310, formation of the texture structure, formation of the second type region 310s, formation of the passivation film 313, formation of the anti-reflective film 314, formation of the protective film 315, and formation of the electrodes.

[0161] <<Preparation of semiconductor substrates>> For example, a semiconductor substrate 310 is prepared as shown in Figure 8. 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 is prepared, for example, by an existing Czochralski (CZ) method or casting method. It can be formed using the following methods. Here, we will describe an example using a p-type polycrystalline silicon ingot as the first conductivity type, which is produced by a casting method. A semiconductor substrate 310 is fabricated by slicing this ingot to a desired thickness of, for example, 250 μm or less. Here, for example, by etching the surface of the semiconductor substrate 310 with a small amount of aqueous solution such as sodium hydroxide, potassium hydroxide, or hydrofluoric acid, the mechanically damaged layer and the contaminated layer at the cut surface of the semiconductor substrate 310 can be removed.

[0162] <<Formation of Texture Structure>> For example, as shown in Figure 9, a structure with fine irregularities (also called a textured structure) is formed on the first surface 310a of the semiconductor substrate 310. The textured structure can be formed by wet or dry etching. Wet etching can be carried out using, for example, an alkaline aqueous solution such as sodium hydroxide or an acidic aqueous solution such as hydrofluoric acid. Dry etching can be carried out using, for example, reactive ion etching (RIE). This can be implemented using laws such as the ) Act.

[0163] <<Formation of the second conductivity region>> For example, as shown in Figure 10, a second type region 310s, which is a region of n-type semiconductor as a second conductivity type, is formed on the first surface 310a of the semiconductor substrate 310 that has a textured structure. More specifically, a second type region 310s, which is a region of n-type semiconductor as a second conductivity type, is formed on the surface layer of the first surface 310a of the semiconductor substrate 310 that has a textured structure. The second type region 310s can be formed, for example, using a coating thermal diffusion method or a gas-phase thermal diffusion method. For the coating thermal diffusion method, for example, a method is applied in which paste-like phosphorus pentoxide (P2O5) is applied to the surface of the semiconductor substrate 310 and phosphorus is thermally diffused. For the gas-phase thermal diffusion method, for example, a method is applied in which gaseous phosphorus oxychloride (POCl3) is used as a diffusion source. Here, for example, if a type 2 region 310s is also formed on the second surface 310b side of the semiconductor substrate 310, the type 2 region 310s formed on the second surface 310b side is removed by etching with an aqueous solution of hydrofluoric acid. Then, for example, phosphorus glass that adhered to the first surface 310a side of the semiconductor substrate 310 when forming the type 2 region 310s 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 type 2 region 310s may be formed by a vapor-phase thermal diffusion method or the like, and then the diffusion mask may be removed.

[0164] <<Formation of passivation membrane>> For example, a passivation film 313 is formed on at least the second surface 310b of the semiconductor substrate 310. For example, as shown in Figure 11, 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 may consist of, for example, a film mainly containing aluminum oxide. Here, the passivation film 313 can be formed by, for example, atomic layer deposition (ALD) method. According to the ALD method, for example, a semiconductor substrate A passivation film 313 can be formed around the entire periphery of 310, including the end face. In the ALD method for forming the passivation film 313, first, a semiconductor substrate 310 with the type 2 region 310s formed is placed in the chamber of the film deposition apparatus. Then, while the semiconductor substrate 310 is heated to a temperature range of approximately 100 degrees Celsius to 250 degrees Celsius, steps A to D are repeated multiple times to form a passivation film 313 mainly containing aluminum oxide. This forms a passivation film 313 with a desired thickness.

[0165] [Step A] An aluminum raw material, such as trimethylaluminium (TMA), for forming aluminum oxide is supplied onto the semiconductor substrate 310 along with a carrier gas such as argon (Ar) gas or nitrogen gas. As a result, the aluminum raw material is adsorbed all around the semiconductor substrate 310. The time for which the TMA is supplied is set to, for example, 15 milliseconds to about 3000 milliseconds. At the start of Step A, for example, the surface of the semiconductor substrate 310 is terminated with hydroxyl groups (OH groups). 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 above.

[0166] [Step B] The chamber of the film deposition apparatus is purified with nitrogen gas. Here, aluminum raw materials are removed from the chamber, and aluminum raw materials other than those chemically adsorbed at the atomic layer level are removed from the aluminum raw materials that have been physically and chemically adsorbed onto the semiconductor substrate 310. The time for purifying the chamber with nitrogen gas is set to, for example, 1 second to several tens of seconds.

[0167] [Step C] An oxidizing agent such as water or ozone gas is supplied into the chamber of the film deposition apparatus. This removes the alkyl groups contained in the TMA and replaces them with OH groups. This forms an atomic layer of aluminum oxide on the semiconductor substrate 310. Here, the time for which the oxidizing agent is supplied into the chamber is set to, for example, about 750 milliseconds to 1100 milliseconds. Here, for example, hydrogen may be supplied into the chamber along with the oxidizing agent to make the aluminum oxide contain hydrogen atoms.

[0168] [Step D] The chamber of the film deposition apparatus is purified with nitrogen gas. This removes the oxidizing agent in the chamber. For example, oxidizing agents that did not contribute to the reaction during the formation of atomic layer-level aluminum oxide on the semiconductor substrate 310 are removed. The time for purifying the chamber with nitrogen gas is set to, for example, 1 second to several tens of seconds.

[0169] <<Anti-reflective coating formation>> For example, as shown in Figure 11, an anti-reflective film 314 is formed on the passivation film 313. The anti-reflective film 314 may be composed of, for example, a silicon nitride film. Here, the anti-reflective film 314 can be formed using, for example, plasma-enhanced chemical vapor deposition (PECVD) or sputtering. When using the PECVD method, the semiconductor substrate 310 is preheated to a temperature higher than the temperature during the deposition of the anti-reflective film 314. Then, the reaction pressure is set to about 50 Pascals (Pa) to 200 Pa, and a mixed gas of silane and ammonia diluted with nitrogen gas is plasma-decomposed by glow discharge decomposition and deposited on the heated semiconductor substrate 310. This forms an anti-reflective film 314 on the semiconductor substrate 310. Here, the deposition temperature is set to about 350°C to 650°C, and the preheating temperature of the semiconductor substrate 310 is set to about 50°C higher than the deposition temperature. For the high-frequency power supply required for glow discharge, frequencies ranging from approximately 10 kilohertz (kHz) to 500 kHz, or MHz band frequencies such as 13.5 megahertz (MHz), are used. The gas flow rate is determined appropriately depending on the size of the reaction chamber. For example, the gas flow rate is set in the range of approximately 150 milliliters per minute to 6000 milliliters per minute. Here, the value obtained by dividing the ammonia gas flow rate B by the silane gas flow rate A (B / A) is set in the range of 0.5 to 1.5.

[0170] <<Formation of protective film>> For example, as shown in Figure 12, 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 large number of through holes. The protective film 315 can be formed by, for example, a wet or dry process. A wet process may include, for example, a process using the coating of a solution. A dry process may include, for example, a process using the PECVD method or the sputtering method. For example, if a wet process using the coating of a solution is employed, the protective film 315 is formed by coating the passivation film 313 with a desired pattern in a form, at least on the second surface 310b side of the semiconductor substrate 310, and then drying the solution. The desired pattern includes a large number of through holes. Here, for example, an insulating paste is used as the solution. As the insulating paste, for example, an insulating paste containing a siloxane resin, an organic solvent, and a plurality of fillers, which are the raw materials for the protective film 315, is employed. Siloxane resins are siloxane compounds having siloxane bonds (Si-O-Si bonds). For example, siloxane resins include low molecular weight resins with a molecular weight of 15,000 or less, produced by hydrolysis and condensation polymerization of alkoxysilanes or silazanes. The solution can be applied using methods such as screen printing. The solution can be dried after application using methods such as a hot plate or a drying oven.

[0171] <<Electrode Formation>> For example, as shown in Figure 3, a first electrode 311 and a second electrode 312 are formed.

[0172] Here, for example, a material for forming the first electrode 311 (also called the 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 an anti-reflective film 314 formed on the first surface 310a. Then, the first electrode 311 is formed by heating this first electrode material. For example, if the main component of the material of the first electrode 311 is silver, silver paste is used as the first electrode material. In this case, the arrangement of the first electrode material is carried out, for example, by coating the silver paste. The coating of the silver paste can be achieved, for example, by a screen printing method. Here, the solvent in the silver paste may be evaporated by drying the coated silver paste at a predetermined temperature. After that, for example, the silver paste is fired in a firing furnace under conditions where the maximum temperature is about 600°C to 850°C and the heating time is about several tens of seconds to several tens of minutes. This makes it possible to form the first electrode 311.

[0173] Furthermore, here, for example, a material for forming the second electrode 312 (also called the second electrode material) is arranged in a desired pattern on the second surface 310b side of the semiconductor substrate 310. More specifically, for example, the material for forming the second electrode 312 (also called the second electrode material) is arranged on the protective film 315, in the numerous through-holes of the protective film 315, and in the multiple holes of the protective film 315. Then, the second electrode 312 is formed by heating this second electrode material. For example, if the main component of the material for the second output section 312b is silver and the main component of the material for the second current collector section 312c is aluminum, then silver paste and aluminum paste are used as the second electrode material. In this case, the arrangement of the second electrode material is carried out, for example, by coating the silver paste and coating the aluminum paste. The coating of silver paste and the coating of aluminum paste can be achieved, for example, by screen printing. Here, for example, silver paste is applied to the second surface 310b of the semiconductor substrate 310 in a desired pattern. More specifically, for example, silver paste is applied to the passivation film 313 exposed from multiple holes in the protective film 315. Also, for example, aluminum paste is applied to the second surface 310b of the semiconductor substrate 310 in a desired pattern that contacts a portion of the applied silver paste. More specifically, for example, aluminum paste is applied to the protective film 315 on the second surface 310b, inside the numerous through-holes of the protective film 315, and on a portion of the applied silver paste. Here, the applied silver paste and aluminum paste may be dried at a predetermined temperature to evaporate the solvent in the silver paste and aluminum paste. After that, for example, the silver paste and aluminum paste are fired in a firing furnace under conditions where the maximum temperature is about 600°C to 850°C and the heating time is about several tens of seconds to several tens of minutes. This allows the second electrode 312 to be formed. When the aluminum paste is fired, the aluminum paste placed in the numerous through-holes of the protective film 315 undergoes firing penetration (also called fire-through) of the passivation film 313, forming a BSF region 310t on the surface of the first type region 310f.Here, for example, the second output section 312b and the second current collector section 312c may be formed simultaneously, or the second current collector section 312c may be formed after the second output section 312b, or the second output section 312b may be formed after the second current collector section 312c.

[0174] Here, for example, the first electrode 311 and the second electrode 312 may be formed by applying the respective metal pastes and then firing them simultaneously.

[0175] <1-4. Manufacturing of solar cell modules> An example of a manufacturing method for the solar cell module 100 according to the first embodiment will be described with reference to Figures 13 and 14.

[0176] First, prepare the first protective member 1. Here, for example, the first protective member 1 may be a rectangular flat or sheet-like member with a translucent surface.

[0177] Next, as shown in Figures 13 and 14, for example, the first protective member 1, the first sheet material 41s, the solar cell section 3, the second sheet material 42s, and the second protective member 2 are stacked in the order described above to form a laminate 10s. In the laminate 10s, for example, the portion of the third wiring material 34 connected to the solar cell section 3 that is connected to the terminal box J1 or the like outside the power generation unit 10 is positioned so that it is exposed to the outside of the laminate 10s.

[0178] The first sheet material 41s is a resin sheet material that forms the basis of the first encapsulant 41. For example, EVA can be used as the material for this resin sheet material. In the laminate 10s, the first sheet material 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 material 41s is located on top of the first protective member 1, and the solar cell section 3 is located on top of the first sheet material 41s. In a plan view, the first sheet material 41s has a rectangular shape, which is an example of a rectangular shape. The first sheet material 41s may consist of one sheet or two or more sheets.

[0179] The second sheet material 42s is a resin sheet material that forms the basis of the second encapsulant material 42. For example, EVA can be used as the material for this resin sheet material. The second sheet material 42s may contain a pigment. In the laminate 10s, the second sheet material 42s is located between the solar cell section 3 and the second protective member 2. In other words, in the laminate 10s, the second sheet material 42s is located on top of the solar cell section 3, and the second protective member 2 is located on top of the second sheet material 42s. In a plan view, the second sheet material 42s has a rectangular shape, which is an example of a rectangular shape. The second sheet material 42s may consist of one sheet or two or more sheets.

[0180] Next, for example, a lamination process is performed on the laminate 10s. In this lamination process, for example, a laminating device (also called a laminator) is used to integrate the laminate 10s. For example, in a laminator, the laminate 10s is placed on a heater plate in the chamber, and the pressure inside the chamber is reduced from 50 Pascals (Pa) to about 150 Pa while the laminate 10s is heated to about 100°C to 200°C. At this point, the first sheet material 41s and the second sheet material 42s become somewhat fluid due to the heating. In this state, the laminate 10s can be integrated by pressing it in the +Z direction with a pressing body such as a diaphragm sheet inside the chamber. Next, a crosslinking process is performed on the laminate 10s. In this crosslinking process, for example, a crosslinking furnace is used to heat the integrated laminate 10s to about 110°C to 210°C. This process imparts rubber elasticity to the first sheet material 41s and the second sheet material 42s, and also improves the heat resistance of the first sheet material 41s and the second sheet material 42s.

[0181] This makes it possible to manufacture the power generator 10.

[0182] After lamination, the terminal box J1 and frame 6 may be attached to the power generation unit 10 as appropriate. In this case, for example, a portion of the third wiring material 34 that is pulled out from the solar cell section 3 to the outside of the power generation unit 10 is appropriately connected to the terminals in the terminal box J1. Also, for example, when attaching the frame 6 along the outer circumference of the power generation unit 10, a low moisture permeability sealing material such as a butyl resin is filled between the outer circumference of the power generation unit 10 and the frame 6. This makes it possible to manufacture the solar cell module 100 according to the first embodiment.

[0183] <1-5. Summary of the First Embodiment> 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 portion 311f1 is greater than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. As a result, for example, when a 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 busbar portion 311b applies force to the busbar portion 311b, the occurrence of disconnection in the first portion P1 connected to the first end portion Ep1 of the multiple first finger portions 311f1 can be reduced. As a result, durability can be improved in the solar cell element 31 and the solar cell module 100, thereby improving reliability. Furthermore, compared to, for example, a configuration in which the width of all finger portions 311f is equally large, or a configuration in which all finger portions 311f have the same structure as the first finger portion 311f1, the amount of sunlight that is blocked from entering the semiconductor substrate 310 by the multiple second finger 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 increased. 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 amount of material required to form the multiple finger portions 311f can be reduced.

[0184] 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 greater than the width of the third portion (second connection portion) P3 of the second finger portion 311f2. Therefore, regardless of whether a force is applied to the first end portion Ep1 in the -Y direction as the first direction or the +Y direction as the second direction by the portion of the first wiring material 32 that constitutes the third end E3, the stress on the first portion P1 of the first finger portion 311f1 may be small.

[0185] Furthermore, for example, even if the first end portion Ep1 of the busbar portion 311b partially peels off from the semiconductor substrate 310 due to 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 breaks may be extended. 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 large.

[0186] This reduces the occurrence of disconnections in the first portion P1 connected to the first end portion Ep1 in multiple first finger portions 311f1.

[0187] As a result, the durability of the solar cell element 31 and the solar cell module 100 can be improved, thereby increasing their reliability. Furthermore, compared to, for example, a configuration in which all finger portions 311f have equally large widths, or a configuration in which all finger portions 311f have the same structure as the first finger portion 311f1, the amount of sunlight that is blocked from entering the semiconductor substrate 310 by the multiple second finger 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 increased. 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 amount of material required to form the multiple finger portions 311f can be reduced.

[0188] <2. Other Embodiments> This disclosure is not limited to the first embodiment described above, and various modifications and improvements are possible without departing from the gist of this disclosure.

[0189] <2-1. Second Embodiment> In the solar cell element 31 according to the first embodiment described above, for example, as shown in Figure 15, the first region A1 may include a second end portion Ep2 located on the second end E2 side of the busbar portion 311b instead of a first end portion Ep1 located on the first end E1 side of the busbar portion 311b. Furthermore, 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.

[0190] 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 the island portion Ip1 located furthest to the second end E2 among a plurality of island portions Ip1 in one busbar portion 311b. The second region A2 also includes island portions Ip1 different from the first island portion Ip11 among a plurality of island portions Ip1 in one busbar portion 311b. In the example of Figure 15, in one busbar portion 311b, the second region A2 includes all island portions Ip1 except the first island portion Ip11 among a 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.

[0191] Furthermore, in the solar cell element 31 according to the second embodiment, for example, each of the multiple first finger portions 311f1 is connected to the first island portion Ip11, which is the island portion Ip1 located furthest towards the second end E2 among the multiple island portions Ip1 in one busbar portion 311b. And, 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 Ip11 located furthest towards the second end E2 among the multiple island portions Ip1 in one busbar portion 311b. More specifically, for example, each first finger portion 311f1 is connected to the side in the +X direction as a third direction and the side in the -X direction as a fourth direction in the first island portion Ip11, respectively. For example, each first finger portion 311f1 includes two first portions P1 connected to the side of the first island portion Ip11 in the +X direction as a third direction and the side of the first island portion Ip11 in the -X direction as a fourth direction, respectively. More specifically, for example, each first finger portion 311f1 includes one first portion P1 connected to the side of the first island portion Ip11 in the +X direction as a third direction, and one first portion P1 connected to the side of the first island portion Ip11 in the -X direction as a fourth direction. Also, for example, a second portion P2 of the first finger portion 311f1 is separated from the first island portion Ip11, which is the island portion Ip1 located furthest to the second end E2 among a plurality of island portions Ip1 in one busbar portion 311b. In each first finger portion 311f1, the second portion P2 is, for example, a portion different from the first portion P1.

[0192] Furthermore, in the solar cell element 31 according to the second embodiment, for example, each of the multiple second finger portions 311f2 is connected to an island portion Ip1 different from the first island portion Ip11 among the multiple island portions Ip1 in one busbar portion 311b. And the third portion P3 of the second finger portion 311f2 is connected to an island portion Ip1 different from the first island portion Ip11 among the multiple island portions Ip1 in one busbar portion 311b. More specifically, for example, each second finger portion 311f2 is connected to the side in the +X direction as a third direction and the side in the -X direction as a fourth direction in an island portion Ip1 different from the first island portion Ip11 among the multiple island portions Ip1 in one busbar portion 311b. Furthermore, for example, each second finger portion 311f2 includes two third portions P3 connected to the side in the +X direction as a third direction and the side in the -X direction as a fourth direction in an island portion Ip1 that is different from the first island portion Ip11 among the multiple island portions Ip1. More specifically, for example, each second finger portion 311f2 includes one third portion P3 connected to the side in the +X direction as a third direction in an island portion Ip1 that is different from the first island portion Ip11, and one third portion P3 connected to the side in the -X direction as a fourth direction in an island portion Ip1 that is different from the first island portion Ip11. Also, for example, the fourth portion P4 of the second finger portion 311f2 is separated from an island portion Ip1 that is different from the first island portion Ip11 among the multiple island portions Ip1 in one busbar portion 311b. In each second finger portion 311f2, the fourth portion P4 is, for example, a different portion from the third portion P3.

[0193] 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 in the -Y direction as the first direction is smaller than the width of the first portion P1. In other words, the width of the first portion (first connection portion) P1 of the first finger portion 311f1, which is a part of the multiple finger portions 311f, is selectively increased. As a result, compared to, for example, a configuration in which the widths of all finger portions 311f are equally large, or a configuration in which all finger portions 311f have the same structure as the first finger portion 311f1, the amount of sunlight that is blocked from entering the semiconductor substrate 310 by the multiple second finger 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 increased. In addition, the amount of material required to form the multiple finger portions 311f can be reduced. From another point of view, for example, the width of the first portion P1 of the first finger portion 311f1 is larger than the width of the third portion P3 of the second finger portion 311f2. As a result, for example, when a solar cell module 100 is manufactured using the solar cell element 31 according to the second embodiment, even if the first wiring material 32 joined to the busbar portion 311b applies force to the busbar portion 311b, the occurrence of disconnection in the first portion P1 connected to the first region A1 of the plurality of first finger portions 311f1 can be reduced.

[0194] As a result, the durability of the solar cell element 31 and the solar cell module 100 can be improved, thereby increasing their reliability. Therefore, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved.

[0195] The solar cell element 31 according to the second embodiment described above can be realized, for example, by rotating the solar cell element 31 according to the first embodiment described above by 180 degrees around the Z-axis.

[0196] 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, but using the solar cell element 31 according to the second embodiment instead of the solar cell element 31 according to the first embodiment. In this case, for example, the first wiring material 32 is joined to the busbar portion 311b in substantially the same form as the first embodiment, as shown in Figure 16. Here, the first wiring material 32 includes the portion on the third end E3 side joined to the first end portion Ep1 (for example, the seventh island-shaped portion Ip17) of the busbar portion 311b.

[0197] Here, let's consider a case where the solar cell module 100 is installed and used outdoors. In this case, for example, during the day, the temperature of the solar cell module 100 rises in response to sunlight irradiation and the power generation by the solar cell module 100 in accordance with that sunlight irradiation. 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 temperature rise and contraction due to temperature decrease repeatedly occur in each part of the solar cell module 100. That is, due to the difference in thermal expansion coefficients according to the materials that make up each part of the solar cell module 100, stress can be repeatedly applied and relieved within the solar cell module 100.

[0198] For example, let's assume that the material of the sealing material 4 is EVA. For example, the instantaneous coefficient of thermal expansion of EVA is 16 × 10⁻⁶. -5 [1 / K] to 20 × 10 -5 It is approximately [1 / K]. Therefore, in the solar cell module 100, the encapsulant 4 may undergo relatively large expansion due to the rise in temperature.

[0199] For example, in the sealing material 4, the portion located between the first solar cell element 31 and the second solar cell element 31, which are adjacent to each other in the first direction (-Y), expands in response 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 pulling force in the +Z direction is applied to the portion of the first wiring material 32 that is joined to the busbar portion 311b by the first joining portion 321, and a pulling force in the -Z direction is applied to the portion of the first wiring material 32 that is joined to the second output portion 312b by the second joining portion 322. As a result, at the second end portion Ep2 of the busbar portion 311b of the first solar cell element 31, located near the second end E2 side of the second solar cell element 31, there is a risk that the busbar portion 311b may partially detach from the semiconductor substrate 310, starting from the second end E2 side. In other words, there is a risk that delamination may occur between the semiconductor substrate 310 and the first electrode 311, starting from the second end E2 side. Subsequently, repeated temperature increases due to sunlight irradiation and power generation during the day, and temperature decreases at night, cause repeated thermal expansion and contraction of the first wiring material 32. At this time, in accordance with the displacement caused by the thermal expansion and contraction of the first wiring material 32, displacement also occurs in the portion of the busbar portion 311b that has detached from the semiconductor substrate 310. Furthermore, since the portion of the busbar portion 311b that has detached from the semiconductor substrate 310 cannot support the load caused by the displacement, stress is generated at the connection point between the finger portion 311f, which has not detached from the semiconductor substrate 310, and the partially detached busbar portion 311b.

[0200] As a result of the above, for example, in the second end portion Ep2 of the busbar portion 311b of the first solar cell element 31, located on the second end E2 side near the second solar cell element 31, a relatively large displacement may occur due to the first wiring material 32. Therefore, for example, in the first solar cell element 31, a relatively large stress 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-shaped portion Ip11).

[0201] More specifically, for example, the portion of the encapsulating material 4 located between the adjacent first solar cell element 31a and the second solar cell element 31b expands in response to the 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 adjacent first solar cell element 31a and the second solar cell element 31b, a pulling force is applied in the +Z direction to the portion of the first wiring material 32 that is joined to the busbar portion 311b by the first joining portion 321, and a pulling force is applied in the -Z direction to the portion of the first wiring material 32 that is joined to the second output portion 312b by the second joining portion 322. As a result, the portion located on the second end E2 side near the second solar cell element 31b in the busbar portion 311b of the first solar cell element 31a expands. At the second end portion Ep2, there is a risk that the busbar portion 311b may partially detach from the semiconductor substrate 310, starting from the second end E2 side. In other words, there is a risk that delamination may occur between the semiconductor substrate 310 and the first electrode 311, starting from the second end E2 side. Subsequently, repeated temperature increases due to sunlight irradiation and power generation during the day, and temperature decreases at night, cause repeated thermal expansion and contraction of the first wiring material 32. At this time, in response to the displacement caused by the thermal expansion and contraction of the first wiring material 32, displacement also occurs in the portion of the busbar portion 311b that has detached from the semiconductor substrate 310. Since the portion of the busbar portion 311b that has detached from the semiconductor substrate 310 cannot support the load caused by the displacement, stress occurs at the connection point between the undetached finger portion 311f and the partially detached busbar portion 311b from the semiconductor substrate 310.

[0202] As a result of the above, for example, the second solar cell in the busbar portion 311b of the first solar cell element 31a In the second end portion Ep2 located on the second end E2 side near the battery element 31b, relatively large displacement may occur due to the first wiring material 32. Therefore, for example, in the first solar cell element 31a, the second end portion Ep2 (for example, the first island-shaped portion Ip11) is connected A relatively large stress may occur in the first portion P1 of the first finger portion 311f1.

[0203] 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 greater 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 busbar portion 311b, it is possible that the stress on the first portion P1 of the first finger portion 311f1 connected to the second end portion Ep2 (for example, the first island-shaped portion Ip11) will be reduced.

[0204] Furthermore, for example, even if the second end portion Ep2 of the busbar portion 311b partially peels off from the semiconductor substrate 310 due to 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 breaks may be extended. 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 large.

[0205] This reduces the occurrence of disconnections in the first portion P1 connected to the second end portion Ep2 (for example, the first island-shaped portion Ip11) in multiple first finger portions 311f1.

[0206] As a result, the reliability of the solar cell element 31 and the solar cell module 100 can be improved by enhancing their durability.

[0207] From another perspective, 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 portion 311f2 is smaller than the width of the first portion (first connection portion) P1 of the first finger portion 311f1. In other words, the width of the first portion (first connection portion) P1 of the first finger portion 311f1, which is a part of the multiple finger portions 311f, is selectively increased. Therefore, compared to, for example, a configuration in which the widths of all finger portions 311f are equally large, or a configuration in which all finger portions 311f have the same structure as the first finger portion 311f1, the amount of sunlight that is blocked from entering the semiconductor substrate 310 by the multiple second finger 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 increased.

[0208] As a result, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved. In addition, the amount of material required to form the multiple finger portions 311f can be reduced.

[0209] Here, for example, it is conceivable that the first wiring material 32 is joined to the busbar portion 311b while being shifted overall in the +X direction (third direction) or the -X direction (fourth direction) with respect to the center of the busbar portion 311b in the +X direction (third direction). In this case, for example, the position of the first wiring material 32 joined to the second end portion Ep2 (e.g., the first island-shaped portion Ip11) is shifted from the center in the width direction of the second end portion Ep2 (e.g., the first island-shaped portion Ip11). This width direction may be along the +X direction (third direction). As a result, the first wiring material 32 approaches the first finger portion 311f1, and the force that the first wiring material 32 applies to the second end portion Ep2 (e.g., the first island-shaped portion Ip11) may be more likely to be applied to the first portion P1. Even in this case, if the width of the first part (first connection part) P1 of the first finger part 311f1 is greater than the width of the third part (second connection part) P3 of the second finger part 311f2, it is possible that the stress on the first part P1 will be reduced.

[0210] Furthermore, for example, even if the second end portion Ep2 of the busbar portion 311b partially peels off from the semiconductor substrate 310 due to 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 breaks may be extended. 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 large.

[0211] Therefore, in multiple first finger portions 311f1, the occurrence of disconnection in the first portion P1 connected to the second end portion Ep2 (for example, the first island-shaped portion Ip11) can be reduced.

[0212] Incidentally, as mentioned 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-shaped 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-shaped portion Ip11).

[0213] 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 part (first connection part) P1 of the first finger part 311f1 connected to the second end part Ep2 (e.g., the first island-shaped part Ip11) of the busbar part 311b is greater than the width of the third part (second connection part) P3 of the second finger part 311f2. Therefore, when manufacturing the solar cell module 100 using the solar cell element 31 according to the second embodiment, even if the first wiring material 32 applies a relatively large force to the second end part Ep2 (e.g., the first island-shaped part Ip11), it is possible that the stress on the first part P1 of the first finger part 311f1 connected to the second end part Ep2 (e.g., the first island-shaped part Ip11) will be small.

[0214] Furthermore, for example, even if the second end portion Ep2 of the busbar portion 311b partially peels off from the semiconductor substrate 310 due to 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 breaks may be extended. 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 large.

[0215] This reduces the occurrence of disconnections in the first portion P1 connected to the second end portion Ep2 (for example, the first island-shaped portion Ip11) in multiple first finger portions 311f1.

[0216] As a result, the reliability of the solar cell element 31 and the solar cell module 100 can be improved by enhancing their durability.

[0217] From another perspective, 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 third portion (second connection portion) P3 of the second finger portion 311f2 is smaller than the width of the first portion (first connection portion) P1 of the first finger portion 311f1. In other words, the width of the first portion (first connection portion) P1 of the first finger portion 311f1, which is a part of the multiple finger portions 311f, is selectively increased. Therefore, when manufacturing the solar cell module 100 using the solar cell element 31 according to the second embodiment, the amount of sunlight that is blocked from entering the semiconductor substrate 310 by the multiple second finger portions 311f2 can be reduced compared to, for example, a configuration in which the widths of all finger portions 311f are equally large, or a configuration in which all finger portions 311f have the same structure as the first finger portion 311f1. As a result, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be increased. 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 amount of material required to form the multiple finger portions 311f can be reduced.

[0218] In other words, assuming that a solar cell module 100 is manufactured using the solar cell element 31 according to the second embodiment, the solar cell element 31 according to the second embodiment has a configuration suitable for improving the power generation efficiency and reliability of both the solar cell element 31 and the solar cell module 100. That is, the solar cell element 31 according to the second embodiment can improve the power generation efficiency and reliability of both the solar cell element 31 and the solar cell module 100. Furthermore, it is possible to reduce the amount of material required to form the multiple finger portions 311f.

[0219] Furthermore, if, for example, the busbar 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 of the busbar portion 311b may be greater than the width of the tenth portion (fifth thin wire portion) P10 of the fifth finger portion 311f5. And 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. The size may also be larger. This can reduce the occurrence of disconnection in the ninth portion P9 connected to the second protruding portion Dp2 in the fifth finger portion 311f5, for example. As a result, durability can be improved in the solar cell element 31 and the solar cell module 100, thereby improving reliability. Here, for example, the second end portion Ep2 of the busbar portion 311b may include the second protruding portion Dp2.

[0220] <2-2. Third Embodiment> In each of the above embodiments, for example, as shown in Figure 17, the first region A1 may include both the first end portion Ep1 and the second end portion Ep2 of a single busbar portion 311b. Furthermore, 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.

[0221] In this case, for example, the first end portion Ep1 constituting the first region A1 includes the seventh island portion Ip17, which is the island portion Ip1 located furthest towards the first end E1 among the multiple island portions Ip1 in one busbar portion 311b. For example, the second end portion Ep2 constituting the first region A1 includes the first island portion Ip11, which is the island portion Ip1 located furthest towards the second end E2 among the multiple island portions Ip1 in one busbar portion 311b. Also, for example, the second region A2 includes island portions Ip1 that are different from the first island portion Ip11 and the seventh island portion Ip17 among the multiple island portions Ip1 in one busbar portion 311b. In the example of Figure 17, in one busbar portion 311b, the second region A2 includes all island portions Ip1 except for the first island portion Ip11 and the seventh island portion Ip17. 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.

[0222] If this configuration is adopted, for example, two or more first finger portions 311f1 having the same characteristics are connected to each of the pair of first end portions Ep1 and second end portions Ep2 in the Y direction, which is the longitudinal direction of the busbar portion 311b. This can reduce the occurrence of errors in the desired orientation of the solar cell elements 31 when manufacturing the solar cell module 100 using the solar cell elements 31 according to the third embodiment. As a result, for example, the workability in manufacturing the solar cell module 100 can be improved. Also, for example, design constraints on the solar cell module 100 can be reduced.

[0223] Furthermore, in this case, the occurrence of wire breakage can be reduced in the first portion P1 connected to the first end portion Ep1 and the second end portion Ep2, respectively, among the multiple first finger portions 311f1.

[0224] 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, but using the solar cell element 31 according to the third embodiment instead of using the solar cell element 31 according to each of the above embodiments. In this case, for example, the first wiring material 32 is joined to the busbar portion 311b in the same form as in each of the above embodiments, as shown in Figure 18. As a result, 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-shaped portion Ip17) of the busbar portion 311b, and a portion joined to the second end portion Ep2 (for example, the first island-shaped portion Ip11) of the busbar portion 311b.

[0225] According to the solar cell module 100 of the third embodiment, for example, the same or similar operations and effects can be obtained as those of the solar cell module 100 according to the first embodiment and the second embodiment, respectively.

[0226] In this case, for example, the busbar portion 311b may include a first protruding portion Dp1 and a second protruding portion Dp2.

[0227] 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 of the busbar portion 311b may be greater than the width of the eighth portion (fourth thin wire portion) P8 of the fourth finger portion 311f4. Furthermore, 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 wire portion) P3 of the second finger portion 311f2. This can reduce the occurrence of disconnection in the seventh portion P7 connected to the first protruding portion Dp1 in the fourth finger portion 311f4. As a result, the durability of the solar cell element 31 and the solar cell module 100 can be improved, thereby improving reliability.

[0228] Furthermore, 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 of the busbar portion 311b may be greater than the width of the tenth portion (fifth thin wire 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 wire portion) P3 of the second finger portion 311f2. This can reduce the occurrence of disconnection in the ninth portion P9 connected to the second protruding portion Dp2 in the fifth finger portion 311f5. As a result, the durability of the solar cell element 31 and the solar cell module 100 can be improved, thereby improving reliability. Here, for example, the first end portion Ep1 of the busbar portion 311b may include a first protruding portion Dp1, and the second end portion Ep2 of the busbar portion 311b may include a second protruding portion Dp2.

[0229] <2-3. Other Embodiments> In the solar cell element 31 according to each of the above embodiments, for example, as shown in Figure 19, the first region A1 may include some of the multiple connecting portions Cp1. Here, for example, the connecting portion Cp1 included in the first region A1 from among the multiple connecting portions Cp1 is referred to as the first connecting portion Cp1A. Also, for example, the third finger portion 311f3 connected to the first connecting portion Cp1A from among the multiple third finger portions 311f3 is referred to as the third A finger portion 311f3A. Also, for example, the fifth portion (third connection portion) P5 in the third A finger portion 311f3A is referred to as the fifth A portion (also called the third A connection portion) P5A. In this case, for example, in the third A finger portion 311f3A connected to the first connecting portion Cp1A, the width of the fifth A portion (third A connection portion) P5A is greater than the width of the sixth portion (third thin wire portion) P6. Furthermore, for example, the width of the 5A portion (3A connection portion) P5A of the 3A finger portion 311f3A connected to the 1st connection portion Cp1A is greater than the width of the 3rd portion (2nd connection portion) P3 of the 2nd finger portion 311f2. As a result, the occurrence of disconnection in the 5A portion P5A of the 3A finger portion 311f3A can be reduced. Consequently, the durability of the solar cell element 31 and the solar cell module 100 can be improved, thereby improving reliability.

[0230] Here, for example, if the first region A1 includes the first end portion Ep1, the first end portion Ep1 may include the first connecting portion Cp1A. In this case, for example, the first end portion Ep1 may include the connecting portion Cp1 located furthest toward the first end E1 among a plurality of connecting portions Cp1 in one busbar portion 311b as the first connecting portion Cp1A. More specifically, for example, the first end portion Ep1 may include the seventh island portion Ip17, which is the island portion Ip1 located furthest toward the first end E1 among a plurality of island portions Ip1 in one busbar portion 311b, and also include the connecting portion Cp1 connected to this seventh island portion Ip17 as the first connecting portion Cp1A. Also, for example, if the first region A1 includes the second end portion Ep2, the second end portion Ep2 may include the first connecting portion Cp1A. In this case, for example, a configuration may be adopted in which the second end portion Ep2 includes, as the first connecting portion Cp1A, the connecting portion Cp1 located furthest toward the second end E2 among a plurality of connecting portions Cp1 in one busbar portion 311b. More specifically, for example, a configuration may be adopted in which the second end portion Ep2 includes, as the first island portion Ip11 which is the island portion Ip11 located furthest toward the second end E2 among a plurality of island portions Ip1 in one busbar portion 311b, and also includes, as the first connecting portion Cp1A, the connecting portion Cp1 connected to this first island portion Ip11.

[0231] In each of the above embodiments, for example, as shown in Figure 20, the width of the first portion P1 does not have to be constant between the multiple first finger portions 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 finger portion 311f1 is located further along in the -Y direction as the first direction and / or the +Y direction as the second direction. For example, if the first region A1 includes a first end portion Ep1, the width of the first portion P1 may gradually or stepwise increase as the first finger portion 311f1 is closer to the first end E1. For example, if the first region A1 includes a second end portion Ep2, the width of the first portion P1 may gradually or stepwise increase as the first finger portion 311f1 is closer to the second end E2. This allows for the reinforcement of the multiple finger portions 311f in accordance with the ease with which stress concentrates in the multiple finger portions 311f due to the force applied from the first wiring material 32 to the busbar portion 311b in the state of the solar cell module 100. As a result, the occurrence of disconnections in the multiple finger portions 311f can be reduced. Furthermore, by selectively thickening the portion of the multiple finger portions 311f connected to the busbar portion 311b as needed, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be increased, and the amount of material required to form the multiple finger portions 311f can also be reduced.

[0232] In each of the above embodiments, for example, as shown in Figure 20, the width of the third portion P3 does not have to be constant between the multiple second finger portions 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 finger portion 311f2 is located further along in the -Y direction as the first direction and / or the +Y direction as the second direction. For example, if 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 finger portion 311f2 is closer to the first end E1. For example, if 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 finger portion 311f2 is closer to the second end E2. This allows for the reinforcement of the multiple finger portions 311f in accordance with the ease with which stress concentrates in the multiple finger portions 311f due to the force applied from the first wiring material 32 to the busbar portion 311b in the state of the solar cell module 100. As a result, the occurrence of disconnections in the multiple finger portions 311f can be reduced. Furthermore, by selectively thickening the portion of the multiple finger portions 311f connected to the busbar portion 311b as needed, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be increased, and the amount of material required to form the multiple finger portions 311f can also be reduced.

[0233] In each of the above embodiments, for example, as shown in Figure 20, the width of the fifth portion P5 does not have to be constant between the multiple third finger portions 311f3 connected to the connecting 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 finger portion 311f3 is located further along in the -Y direction as the first direction and / or the +Y direction as the second direction. For example, if 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 finger portion 311f3 is closer to the first end E1. For example, if 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 finger portion 311f3 is closer to the second end E2. This allows for the reinforcement of the multiple finger portions 311f in accordance with the ease with which stress concentrates in the multiple finger portions 311f due to the force applied from the first wiring material 32 to the busbar portion 311b in the state of the solar cell module 100. As a result, the occurrence of wire breakage in the multiple finger portions 311f can be reduced. Furthermore, by selectively thickening the portion of the multiple finger portions 311f connected to the connecting portion Cp1 as needed, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be increased, and the amount of material required to form the multiple finger portions 311f can also be reduced.

[0234] In each of the above embodiments, for example, as shown in Figures 4, 15, 17, 19, and 20, the width of the first portion P1 in one first finger portion 311f1 may be constant. In this case, for example, when the first element surface F1 is viewed from above, the first portion P1 may be rectangular. Also, for example, as shown in Figure 21, the width of the first portion P1 in one first finger portion 311f1 may not be constant. For example, the width of the first portion P1 may gradually or in steps increase as it approaches the busbar portion 311b. In this case, for example, when the first element surface F1 is viewed from above, the shape of the first portion P1 may be a polygonal shape such as a triangle or trapezoid, a curved shape such as a semicircle or semiellipse, or a shape that combines a polygonal shape and a curved shape. Here, for example, a predetermined statistical value such as the maximum 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.

[0235] Furthermore, for example, the width of the third portion P3 in one second finger portion 311f2, the width of the fifth portion P5 in one third finger portion 311f3, the width of the seventh portion P7 in one fourth finger portion 311f4, and the width of the ninth portion P9 in one fifth finger portion 311f5 may or may not be constant. The widths of the third portion P3, fifth portion P5, seventh portion P7, and ninth portion P9 may increase gradually or in steps as they approach the busbar portion 311b. In this case, for example, when the first element surface F1 is viewed from above, the shapes of the third portion P3, fifth portion P5, seventh portion P7, and ninth portion P9 may be polygonal shapes such as triangles or trapezoids, curved shapes such as semicircles or semi-ellipses, or shapes that combine polygonal shapes and curved shapes. Here, for example, the widths of the third part P3, the fifth part P5, the seventh part P7, and the ninth part P9 may be assigned predetermined statistical values, such as the maximum or average value of the length in the -Y direction as the first direction.

[0236] In each of the above embodiments, for example, as shown in Figure 22, the first region A1 does not have to include either the first end portion Ep1 or the second end portion Ep2 of the busbar portion 311b. In other words, for example, in one busbar portion 311b, the first region A1 and the second region A2 only need to be in different positions in the -Y direction as the first direction. Even if this configuration is adopted, the multiple finger portions 311f can be reinforced according to the ease with which stress concentrates in the multiple finger portions 311f due to the force applied from the first wiring material 32 to the busbar portion 311b in the state of the solar cell module 100. As a result, the occurrence of disconnections in the multiple finger portions 311f can be reduced. Furthermore, by selectively thickening the portion of some of the multiple finger portions 311f that is connected to the busbar portion 311b, the power generation efficiency of the solar cell element 31 and the solar cell module 100 can be increased. 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 amount of material required to form the multiple finger portions 311f can be reduced.

[0237] In each of the above embodiments, for example, as shown in Figure 23, one busbar portion 311b may be composed of a single strip-shaped portion along the -Y direction as the first direction. In other words, one busbar portion 311b may be composed of a single strip-shaped portion having a longitudinal direction along the -Y direction as the first direction. In this case, the first region A1 of one busbar portion 311b may include, for example, a first end portion Ep1, or a second end portion Ep2, or it may not include either the first end portion Ep1 or the second end portion Ep2. Here, for example, in one busbar portion 311b, all portions other than the first region A1 may be the second region A2. Here, the first end portion Ep1 may be, for example, the portion including the first end E1 when one busbar portion 311b is equally divided into m portions (m is a natural number of 3 or more) along the -Y direction as the first direction. The second end portion Ep2 may include, for example, the portion containing the second end E2 when one busbar portion 311b is equally divided into m portions (where m is a natural number greater than or equal to 3) in the -Y direction as the first direction. Furthermore, if, for example, the length (also called the width) of the busbar portion 311b in the +X direction as the third direction is greater than the width W2 of the first wiring material 32, the first wiring material 32 can be joined at a position offset from the center of the busbar portion 311b in the direction along the +X direction as the third direction (also called the width direction). For this reason, for example, when joining the first wiring material 32 to the busbar portion 311b, a displacement of the position of the first wiring material 32 in the +X direction as the third direction with respect to the busbar portion 311b, and a slight inclination of the longitudinal direction of the first wiring material 32 with respect to the -Y direction as the first direction may be permitted.

[0238] In each of the above embodiments, for example, as shown in Figures 4, 15, 17, 19 to 22, the length (width) of an island-shaped portion Ip1 in the +X direction as the third direction may be constant between multiple island-shaped portions Ip1. Also, for example, as shown in Figure 24, the length (width) of an island-shaped portion Ip1 in the +X direction as the third direction may not be constant between multiple island-shaped portions Ip1. For example, the width of an island-shaped portion Ip1 may gradually or stepwise increase as it is located further along the -Y direction as the first direction and / or the +Y direction as the second direction. For example, the width of an island-shaped portion Ip1 may gradually or stepwise increase as it is closer to the first end E1, and the width of an island-shaped portion Ip1 may gradually or stepwise increase as it is closer to the second end E2. As a result, even if the first wiring material 32 is joined to the busbar portion 311b with its longitudinal direction slightly inclined with respect to the -Y direction as the first direction, the occurrence of the first wiring material 32 approaching the finger portion 311f can be reduced. As a result, even if a force is applied to the busbar portion 311b by the first wiring material 32 in the state of the solar cell module 100, the occurrence of wire breakage at the finger portion 311f can be reduced. Furthermore, for example, the length (width) of the island-shaped portion Ip1 in the +X direction as the third direction can be set according to the ease with which stress concentrates in the multiple finger portions 311f due to the force applied from the first wiring material 32 to the busbar portion 311b in the state of the solar cell module 100. As a result, even if a force is applied to the busbar portion 311b by the first wiring material 32 in the state of the solar cell module 100, the occurrence of wire breakage at the finger portion 311f can be reduced. Furthermore, in a single island-like portion Ip1, the length (width) of the island-like portion Ip1 in the +X direction, which is the third direction, does not have to be constant. For example, in the -Y direction, which is the first direction, and / or the +Y direction, which is the second direction, the width of the island-like portion Ip1 may increase gradually or in steps. In other words, the shape of the island-like portion Ip1 may be trapezoidal.

[0239] In each of the above embodiments, for example, the solar cell element 31 may be a substantially rectangular solar cell element formed by dividing a substantially square solar cell element. Here, for example, a substantially rectangular solar cell element can be manufactured by dividing a substantially square solar cell element into n equal parts (n is a natural number of 2 or more) in the longitudinal direction of the busbar portion 311b. For example, the solar cell element 31 of the third embodiment can be divided into two in the -Y direction as the first direction to manufacture the solar cell element 31 of the first embodiment and the solar cell element 31 of the second embodiment. In this case, for example, it is easy to increase the number of solar cell elements 31 included in each solar cell string 30, and the voltage that the solar cell module 100 can output can be easily increased.

[0240] In each of the above embodiments, for example, the width of the third portion P3 in all second finger portions 311f2 is not limited to a configuration in which the width of the third portion P3 in all second finger portions 311f2 is smaller than the width of the first portion P1 in the first finger portion 311f1. For example, for all second finger portions 311f2 connected to the second region A2, a configuration may be adopted in which the width of the third portion P3 in some second finger portions 311f2 is not smaller than the width of the first portion P1 in the first finger portion 311f1, and the width of the third portion P3 in the remaining plurality of second finger portions 311f2 is smaller than the width of the first portion P1 in the first finger portion 311f1. In this case, each of the some second finger portions 311f2 may be a different finger portion (also called a sixth finger portion) that is not a second finger portion 311f2. Furthermore, the region to which some of the second finger portions 311f2 of the busbar portion 311b are connected may not be included in the second region A2 and may be considered a separate region (also called the third region). Here, if the number of some second finger portions 311f2 is less than the number of the remaining multiple second finger portions 311f2, the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be improved. It is also possible to reduce the amount of material required to form the multiple finger portions 311f. Here, the number of some second finger portions 311f2 may be less than 50% of the total number of second finger portions 311f2, less than 20% of the total number of second finger portions 311f2, or less than 10% of the total number of second finger portions 311f2. For example, the fewer the number of some second finger portions 311f2, the better the power generation efficiency and reliability of the solar cell element 31 and the solar cell module 100 can be. It is also possible to reduce the amount of material required to form the multiple finger portions 311f.

[0241] In each of the above embodiments, for example, in the solar cell element 31, the busbar portion 311b and the finger portion 311f may intersect in a non-orthogonal manner. For example, if the width of the busbar portion 311b gradually increases toward the first end E1 at the first end portion Ep1 of the busbar portion 311b, then it can be said that the finger portion 311f connected to the first end portion Ep1 and the busbar portion 311b intersect in a non-orthogonal manner. For example, if the width of the busbar portion 311b gradually increases toward the second end E2 at the second end portion Ep2 of the busbar portion 311b, then it can be said that the finger portion 311f connected to the second end portion Ep2 and the busbar portion 311b intersect in a non-orthogonal manner. Furthermore, for example, the first direction and the third direction may intersect without being orthogonal. In other words, for example, the first direction and the third direction may intersect at a 90-degree angle, or at an angle other than 90 degrees. For angles other than 90 degrees, for example, angles between 75 degrees and less than 90 degrees may be applied, or angles between 80 degrees and less than 90 degrees may be applied, or angles between 85 degrees and less than 90 degrees may be applied.

[0242] In each of the above embodiments, for example, as shown in Figure 25, the shape of the second electrode 312 when the second element surface F2 is viewed from above may be the same as or similar to the shape of the first electrode 311 when the first element surface F1 is viewed from above. In other words, the second electrode 312 may be a grid-shaped electrode.

[0243] In the example shown in Figure 25, the second electrode 312 includes a plurality of busbar sections 312b as a second output section and a plurality of finger sections 312f as current collectors. Each busbar section 312b is located along the -Y direction, which is the first direction along the second surface 310b. In other words, each busbar section 312b has a longitudinal direction along the -Y direction, which is the first direction. From another perspective, each busbar section 312b has an elongated shape along the -Y direction, which is the first direction. The plurality of busbar sections 312b are arranged in the +X direction, which is the third direction. Each of the plurality of busbar sections 312b may have the same structure. When manufacturing a 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 busbar section 312b. The plurality of finger sections 312f are arranged in the -Y direction, which is the first direction. Each of the multiple finger portions 312f is a linear portion thinner than the busbar portion 312b. Each finger portion 312f is connected to the multiple busbar portions 312b in a manner that intersects with them. In other words, each of the multiple finger portions 312f is connected to the busbar portions 312b in a manner that intersects with them. Each finger portion 312f is located, for example, along the +X direction as a third direction along the second surface 310b. In other words, each finger portion 312f has, for example, a longitudinal direction along the +X direction as a third direction. From another point of view, each finger portion 312f has an elongated linear shape along the +X direction as a third direction. The second electrode 312 may have an auxiliary electrode 312a located along the outer edge in the -X direction on the second surface 310b, and an auxiliary electrode 312a located along the outer edge in the +X direction. Each auxiliary electrode 311a interconnects a number of finger portions 312f. A passivation film 313 may be located on the first type region 310f of the semiconductor substrate 310 in the region where the second electrode 312 is not located. A protective film 315 may be located on the passivation film 313.

[0244] In this case, for example, the shape of the busbar portion 312b of the second electrode 312 when the second element surface F2 is viewed from above is the same as or similar to the shape of the busbar portion 311b of the first electrode 311 when the first element surface F1 is viewed from above. In other words, the busbar portion 312b of the second electrode 312 may have a first region A1 and a second region A2, just like the busbar portion 311b of the first electrode 311. For example, the shape of the multiple finger portions 312f of the second electrode 312 when the second element surface F2 is viewed from above is the same as or similar to the multiple finger portions 311f of the first electrode 311 when the first element surface F1 is viewed from above. In other words, the width of the portion of each of the multiple finger portions 312f connected to the first region A1 (also called the first finger portion) 312f that is connected to the busbar portion 312b may be greater than the width of the portion of each of the multiple finger portions 312f connected to the second region A2 (also called the second finger portion) 312f that is connected to the busbar portion 312b. In other words, the width of the portion of each of the multiple first finger portions 312f connected to the first region A1 that is connected to the busbar portion 312b may be selectively larger. This reduces the occurrence of disconnections in the multiple finger portions 312f of the second electrode 312 through the same mechanism as the multiple finger portions 311f of the first electrode 311. As a result, the reliability of the solar cell element 31 and the solar cell module 100 can be improved by improving durability.

[0245] Here, if the main component of the material of the busbar portion 312b is silver, the busbar portion 312b can be formed by applying silver paste to a desired shape using a screen printing method or the like, and then firing the silver paste. If the main component of the material of the multiple finger portions 312f is aluminum, the multiple finger portions 312f can be formed by applying aluminum paste to a desired shape using a screen printing method or the like, and then firing the aluminum paste. Here, when the second element surface F2 is viewed from above, the busbar portion 312b may have a structure in which a portion mainly composed of silver is surrounded by a portion mainly composed of aluminum. Also, here, the main component of the overall material of the second electrode 312 may be silver.

[0246] Here, for example, if the second protective member 2 and the second sealing material 42 are light-transmitting, the solar cell element 31 may perform photoelectric conversion in response to light incident from the back surface 10b side. In this case, the width of the portion of the finger portion 312f connected to the busbar portion 312b of the finger portion 312f of the plurality of finger portions 312f of the second electrode 312 that is connected to the first region A1 is selectively increased, which can increase the power generation efficiency 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. In addition, the amount of material required to form the plurality of finger portions 312f can be reduced. Here, for example, one of the electrodes of the first electrode 311 and the second electrode 312 may have a structure having a first region A1 and a second region A2. If the second electrode 312 has a first region A1 and a second region A2, and the first electrode 311 does not have a first region A1 and a second region A2, then the names of the first surface 310a and the second surface 310b of the semiconductor substrate 310 may be reversed.

[0247] In each of the above embodiments, for example, the sealing material 4 may not include the second sealing material 42, but may include the first sealing material 41. In this case, the first sealing material 41 covers the solar cell portion 3 between the first protective member 1 and the second protective member 2. In other words, the first sealing material 41 covers the multiple solar cell elements 31 between the first protective member 1 and the second protective member 2.

[0248] In each of the above 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. This can reduce, for example, the occurrence of malfunctions in the solar cell section 3 due to free acids. Also, 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. This can reduce, for example, the occurrence of malfunctions in the solar cell section 3 due to free acids.

[0249] As described above, the solar cell elements 31 and solar cell modules 100 according to each embodiment have been described in detail, but the above descriptions are illustrative in all respects and this disclosure is not limited thereto. Furthermore, the various examples described above can be applied in combination as long as they do not contradict each other. And countless examples not illustrated can be conceived without falling outside the scope of this disclosure. [Explanation of symbols]

[0250] 100 solar modules 3 Solar cell section 31 Solar cell elements 310 Semiconductor substrates 310a 1st page 310b 2nd side 311 1st electrode 311b Busbar section 311f Finger section 311f1 First finger section 311f2 Second finger section 311f3 Third Finger Part 312 Second Electrode 312b Second Output Part, Bus Bar Part 312f Finger Part 31a First Solar Cell Element 31b Second Solar Cell Element 32 First Wiring Material 4 Encapsulant A1 First Region A2 Second Region Cp1 Connection Part E1 First End E2 Second End E3 Third End E4 Fourth End E5 Fifth End E6 Sixth End Ep1 First End Part Ep2 Second End Part Ip1 Island Part

Claims

1. A semiconductor substrate having a first surface and a second surface on the opposite side of the first surface, The first electrode is located on the first surface, The first electrode includes a busbar portion and a plurality of finger portions, The busbar portion is located along the first direction along the first surface, The plurality of finger portions are arranged in the first direction, Each of the aforementioned plurality of finger portions is a linear portion thinner than the busbar portion and is connected to the busbar portion in a manner that intersects with the busbar portion. The busbar portion includes a first region and a second region whose positions in the first direction are different from each other. 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. Each of the plurality of first finger portions includes a first portion connected to the first region and a second portion separated from the first region. Each of the plurality of second finger portions includes a third portion connected to the second region and a fourth portion separated from the second region. The width of the first part is greater than the width of the third part. The busbar portion includes a first island-shaped portion and a second island-shaped portion that are aligned in the first direction, and also includes a connecting portion that connects the first island-shaped portion and the second island-shaped portion. The plurality of finger portions include a third finger portion connected to the connecting portion. The third finger portion includes two fifth portions that intersect the first direction of the connecting portion and are connected to the third direction side along the first surface and to the fourth direction side opposite to the third direction, and a sixth portion that is separated from the connecting portion. A solar cell element in which, in the first direction, the width of each of the two fifth portions is greater than the width of the sixth portion.

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

3. A solar cell element according to claim 2, The first region includes the second end portion located on the second end side of the busbar portion, The plurality of first finger portions include two or more first finger portions connected to the second end portion, wherein the solar cell element.

4. The solar cell section, The solar cell portion comprises 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 is separated from the second solar cell element in a first direction, and the second solar cell element is aligned with the first solar cell element 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 described in 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 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 joined to the busbar portion along the first direction, A solar cell module, wherein the first wiring material includes a portion on the third end side joined to the first end portion.

5. The solar cell section, The solar cell portion comprises 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 is separated from the second solar cell element in a first direction, and the second solar cell element is aligned with the first solar cell element 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 described in claim 1, The busbar 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 busbar portion includes a first end portion located on the first end side, The first region includes the second end portion located on the second end side of the busbar portion, 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 joined to the busbar portion along the first direction, A solar cell module, wherein the first wiring material includes a portion on the third end side joined to the first end portion.

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

7. The solar cell section, The solar cell portion comprises 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 is separated from the second solar cell element in a first direction, and the second solar cell element is aligned with the first solar cell element 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 described in claim 1, The two fifth portions each have a fifth end located in the fourth direction and a sixth end located in the third direction. A solar cell module in which, in the third direction, the length from the fifth end to the sixth end is greater than the width of the first wiring material.

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