Solar cell module and its manufacturing method

Abstract

To provide a solar cell module in which solar cells are connected to one another by a plurality of wiring members.SOLUTION: The solar cell module includes: a semiconductor substrate; a plurality of solar cells including a first electrode and a second electrode alternately formed in parallel in the first direction on the back surface of the semiconductor substrate; a plurality of first wiring members which are formed in a second direction intersecting a first direction for directly connecting the plurality of solar cells and electrically connected to the first electrode by a conductive layer for insulating the second electrode; and a plurality of second wiring members in which the plurality of solar cells are connected in series to form them in the second direction and which are electrically connected to the second electrode by the conductive layer for insulating the first electrode, where each of the plurality of solar cells includes a first pad part which is formed in a region where the first wiring members and the first electrode intersect, and a second pad part which is formed in a region where the second wiring members and the second electrode intersect, and the first pad part or the second pad part has at least one second contact pad part which includes a first contact pad part having a width greater than that of the first or the second electrode, respectively and is larger than the first contact pad part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a solar cell module in which solar cells are interconnected by a plurality of wiring members, and to a manufacturing method thereof. [Background technology]

[0002] Recently, as the depletion of existing energy resources such as oil and coal is predicted, interest in alternative energy sources to replace them is growing. Among them, solar cells, which generate electrical energy from solar energy, are attracting attention because they are an abundant energy resource and do not cause environmental pollution.

[0003] A typical solar cell has a conductive substrate that contains p-type or n-type impurities. The device has an emitter region and a back surface field region (BSF) that are doped with impurities at a higher concentration than the substrate, and electrodes that are electrically connected to the emitter region and the back surface field region, respectively. At this time, a pn junction is formed between the substrate and the emitter region, and electrical energy is produced using the photoelectric effect.

[0004] When light is incident on a solar cell, multiple electron-hole pairs are generated in the semiconductor. The electron-hole pairs are separated into electrons and holes, and the electrons and holes move toward the n-type and p-type semiconductors, for example, toward the emitter and back surface field regions, and are collected by electrodes. These electrodes are connected with wires to obtain electricity. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to provide a solar cell module with improved efficiency. [Means for solving the problem]

[0006] A solar cell module according to one embodiment of the present invention includes a semiconductor substrate, a plurality of solar cells including first electrodes and second electrodes formed in a first direction on a rear surface of the semiconductor substrate so as to be alternately parallel to each other, a plurality of first wiring members formed in a second direction intersecting the first direction, electrically connected to the first electrodes by a conductive layer and insulated from the second electrodes in order to connect the plurality of solar cells in series with each other, and a second wiring member formed in the second direction, electrically connected to the second electrodes by a conductive layer and insulated from the first electrodes in order to connect the plurality of solar cells in series with each other, each of the plurality of solar cells includes a first pad portion formed in a region where the first wiring member and the first electrode intersect and a second pad portion formed in a region where the second wiring member and the second electrode intersect, and the first pad portion or the second pad portion has a first contact pad portion having a width greater than the width of each of the first and second electrodes, and has at least one second contact pad portion having a size greater than the first contact pad portion.

[0007] Here, at least a portion of the second electrode insulated from the first wiring member or at least a portion of the first electrode insulated from the second wiring member may include a disconnection portion where the electrode is partially disconnected.

[0008] Here, a bank may be formed that selectively covers the tip of the electrode at the disconnection portion.

[0009] Furthermore, an insulating layer may be formed on at least a portion of the insulated portion between the first electrode and the second wiring member, or at least a portion of the insulated portion between the second electrode and the first wiring member.

[0010] In addition, the first and second pads may be formed of the same material as the first electrode or the second electrode, and at least one of the first and second pads may include a slit formed as a narrow groove.

[0011] Alternatively, the first and second pad portions may be formed of a conductive material different from that of the first electrode or the second electrode.

[0012] Here, the width of the plurality of first electrodes and the plurality of second electrodes can be 100 μm to 600 μm, and the thickness can be 0.1 μm to 10.0 μm.

[0013] The width of the first wiring member and the second wiring member may be 1 mm to 50 mm, and the thickness may be 25 μm to 200 μm.

[0014] Additionally, each of the multiple solar cells may include multiple dispersion layers that selectively attach the first wiring material and the second wiring material to the semiconductor substrate in the region between the insulating layer and the conductive layer.

[0015] Here, the plurality of dispersion layers may be made of the same material as the first electrode or the second electrode, or may be made of the same material as the insulating layer or the conductive layer.

[0016] A solar cell module according to another example of the present invention includes a semiconductor substrate, a plurality of solar cells including first electrodes formed parallel to each other on a front surface of the semiconductor substrate and a second electrode formed on a rear surface of the substrate, and a plurality of wiring members connecting the first electrodes formed on a first solar cell adjacent to each other among the plurality of solar cells to a plurality of second electrodes formed on a second solar cell, at least a portion of the first electrodes in each of the plurality of solar cells have a plurality of first pad portions having a width greater than the line width of the first electrode in an area where the wiring member and the first electrode intersect, and at least one of the plurality of first pad portions is a different size than the remaining pad portions.

[0017] Here, the plurality of first pad portions may include an auxiliary pad portion having a first size and an extended pad portion having a second size larger than the first size.

[0018] In addition, the second electrodes are formed in a plurality of pieces parallel to each other and have a plurality of second pad portions formed in areas where the wiring material and the second electrodes intersect, and the plurality of second pad portions may include auxiliary pad portions and extended pad portions having different sizes.

[0019] In this case, the width or length of the extended pad portion of the second pad portion may be greater than the width or length of the auxiliary pad portion.

[0020] In addition, the extended pad portion of each of the first and second pad portions may be located in an outer region of the semiconductor substrate than the auxiliary pad portion along the length direction of the wiring member in each of the plurality of solar cells. As an example, the extended pad portion of each of the first and second pad portions may be formed on an outermost first electrode among first electrodes intersecting along the length direction of the wiring member in each of the plurality of solar cells.

[0021] Alternatively, in each of the first and second pad sections, the extended pad section and the auxiliary pad section may be repeatedly arranged in a certain pattern along the length of the wiring material.

[0022] Here, at least one of the width, length, or number of the plurality of first pad portions may be different from at least one of the width, length, or number of the plurality of second pad portions.

[0023] In addition, the number of the first pads may be 6 or more and may be smaller than or equal to the number of the first electrodes, and the number of the second pads may be 6 or more and may be smaller than or equal to the number of the second electrodes. For example, the number of the first pads may be greater than the number of the second pads.

[0024] The solar cell array may further include a plurality of connection electrodes electrically connecting the first pad portions or the second pad portions to the first electrode or the second electrode in a wiring direction in each of the solar cells.

[0025] Here, the line width of the multiple connection electrodes may be the same as or larger than the line width of the first electrode or the second electrode, and may be smaller than the width of the pad portion.

[0026] The plurality of wiring members may include 6 to 30 pieces, and may be formed of wires with a circular cross section and a diameter of 250 μm to 500 μm.

[0027] Here, the width of the extended pad portion of the first pad portion or the second pad portion may be larger than the width of the wiring material and smaller than 2.5 mm.

[0028] In addition, the length of the first pad portion or the second pad portion may be longer than the line width of the first electrode or the second electrode and smaller than 30 mm.

[0029] Furthermore, the ratio (m / n) of the number of the second pad portions (m) to the number (n) of the first pad portions is 0.5 < It is possible that m / n<1.

[0030] In addition, the pitch between the second pads may be larger than the pitch between the first pads, and the pitch between the first electrodes may be equal to or larger than the pitch between the second electrodes. Thus, the number of the second electrodes may be larger than the number of the first electrodes.

[0031] The solar cell may further include a reflector coupled to the wiring material between the first solar cell and the second solar cell. Effect of the Invention

[0032] The solar cell module according to the present invention includes pad portions of different sizes, and can improve the physical adhesion and contact resistance between the wiring material and the electrodes while minimizing bending of the semiconductor substrate. [Brief description of the drawings]

[0033] The drawings attached to this specification show schematic views for easily explaining the invention, and therefore the attached drawings may differ from the actual ones.

[0034] [Figure 1] 1 is a diagram showing an overall view of a solar cell module according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram showing a schematic cross-sectional view of the solar cell shown in FIG. [Diagram 3]FIG. 2 is a diagram showing an overall view of a wiring member in the solar cell module of FIG. [Figure 4] FIG. 2 is a diagram showing a cross-sectional view of a wiring material in the solar cell module of FIG. [Diagram 5] 13A and 13B are diagrams showing the state of a wiring material according to another embodiment. [Figure 6] FIG. 2 is a diagram showing a cross-sectional view of a wiring material. [Figure 7] 11A and 11B are diagrams illustrating a buffer portion formed on a wiring material. [Figure 8] FIG. 2 is a simplified diagram showing the electrodes and wiring members of each solar cell in the solar cell module shown in FIG. 1 and the connections between them. [Figure 9] 9 is a diagram showing a cross-sectional view taken along line II' in FIG. 8. FIG. [Figure 10] 9 is a diagram showing a cross-sectional view taken along line II-II' in FIG. 8. FIG. [Figure 11] FIG. 13 is a diagram showing a state in which a pad portion is formed at the intersection of an electrode and a wiring material. [Figure 12] 12 is a diagram showing a cross-section taken along line III-III' in FIG. 11. FIG. [Figure 13] FIG. 2 is a cross-sectional view showing a pad portion formed from a layer different from the electrode. [Figure 14] FIG. 13 is a diagram showing a state in which the pad portion is configured to further include a slit. [Figure 15] FIG. 13 is a diagram showing a configuration in which the size of the pad portion varies depending on the position. [Figure 16] FIG. 13 is a diagram showing a configuration in which the size of the pad portion varies depending on the position. [Figure 17] FIG. 13 is a diagram showing an electrode structure including a broken portion. [Figure 18] 11A and 11B are diagrams illustrating how the width of a broken portion varies depending on the position. [Figure 19] FIG. 13 is a diagram showing the state of a broken portion including a bank. [Figure 20] FIG. 20 is a diagram showing a cross-sectional view taken along line IV-IV' in FIG. 19. [Figure 21] 4A and 4B are diagrams showing connection electrode portions that electrically connect pad portions; [Figure 22] 22 is a diagram showing a cross-sectional view taken along line VV' in FIG. 21. FIG. [Figure 23] 1 is a diagram showing a flow of a manufacturing method for a solar cell module according to an embodiment; [Figure 24] FIG. 2 is a diagram showing a state in which a dispersion layer is disposed between a conductive layer and an insulating layer. [Diagram 25] 25 is a diagram showing a cross-sectional view taken along line VI-VI' in FIG. 24. FIG. [Figure 26] FIG. 13 is a diagram showing a state in which a dispersion layer is formed on an electrode including a broken portion. [Figure 27] FIG. 27 is a diagram showing a cross-sectional view taken along line VII-VII' in FIG. 26. [Figure 28] FIG. 13 is a diagram showing a state in which the dispersion layer is made up of multiple layers. [Figure 29] FIG. 1 is a diagram showing the overall appearance of a solar cell module made up of solar cells of a conventional structure. [Diagram 30] 30 is a diagram showing a cross-sectional view taken along line XI-XI' in FIG. 29. FIG. [Diagram 31] 30 is a diagram showing a cross-sectional view taken along line XII-XII' in FIG. 29. FIG. [Diagram 32] FIG. 13 is a diagram showing the state of a wiring material. [Diagram 33] FIG. 2 is a diagram showing a state of a first electrode in the first embodiment. [Diagram 34] FIG. 11 is a diagram showing a state of a first electrode according to the second embodiment. [Diagram 35] FIG. 13 is a diagram showing a state of a first electrode in the third embodiment. [Diagram 36] FIG. 13 is a diagram showing the state of a first electrode in the fourth embodiment. [Figure 37] FIG. 13 is a diagram showing the state of a first electrode in the fifth embodiment. [Figure 38] FIG. 23 is a diagram showing the state of a first electrode in the sixth embodiment. [Figure 39] FIG. 13 is a diagram showing the state of a first electrode in the seventh embodiment. [Diagram 40] FIG. 2 is a diagram showing a first electrode including an expansion pad portion and an auxiliary pad portion. [Diagram 41] FIG. 13 is a diagram showing a state in which the second electrode includes an expansion pad portion and an auxiliary pad portion. [Diagram 42] FIG. 1 is a diagram showing an overall configuration of a solar cell module made up of solar cells of a conventional structure, including a reflector. [Diagram 43] FIG. 43 is a diagram showing a cross-sectional view taken along the line AA in FIG. 42. [Diagram 44] 43 is a diagram showing a cross-sectional view taken along the line BB in FIG. 42. [Diagram 45] FIG. 43 is a diagram showing the state of wiring materials in the solar cell module shown in FIG. 42. [Figure 46] FIG. 43 is a diagram showing a first electrode of the solar cell module shown in FIG. [Figure 47] FIG. 43 is a diagram showing a second electrode of the solar cell module shown in FIG. [Figure 48] 11 is a diagram showing the positional relationship between a front pad portion and a rear pad portion. FIG. [Figure 49] 11 is a diagram showing the positional relationship between a front pad portion and a rear pad portion. FIG. [Figure 50] 11 is a diagram showing the positional relationship between a front pad portion and a rear pad portion. FIG. [Figure 51] 11 is a diagram showing the positional relationship between a front pad portion and a rear pad portion. FIG. [Figure 52] This is to explain the reflector of the solar cell module shown in FIG. [Figure 53] FIG. 53 is a diagram showing a cut state along line CC in FIG. 52. [Figure 54] 53A to 53C are diagrams showing various states of the reflector along the CC line direction in FIG. 52. [Figure 55] 53A to 53C are diagrams showing various states of the reflector along the CC line direction in FIG. 52. [Figure 56] 53A to 53C are diagrams showing various states of the reflector along the CC line direction in FIG. 52. [Figure 57] 53A to 53C are diagrams showing various states of the reflector along the CC line direction in FIG. 52. [Figure 58] 53A to 53C are diagrams showing various states of the reflector along the CC line direction in FIG. 52. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The embodiment described below is merely a preferred embodiment and does not represent all of the present invention. In particular, an embodiment created by selectively selecting and combining each component described in the embodiment below also belongs to the present invention because each component has already been described.

[0036] FIG. 1 is a diagram showing the overall appearance of a solar cell module according to one embodiment of the present invention, illustrating the appearance of three solar cells adjacent to each other in the lateral direction.

[0037] Each of the solar cells (10a-10c) has a cubic shape with a small thickness, and a first conductivity type electrode (hereinafter, first electrode) 11 and a second conductivity type electrode (hereinafter, second electrode) 13 that separate and collect charges and holes are formed on the rear surface.

[0038] The first electrodes 11 and the second electrodes 13 may be formed in a first direction so as to be alternately parallel to each other on the rear surface of the semiconductor substrate 15. For example, as shown in Fig. 1, the first electrodes 11 and the second electrodes 13 are arranged so as to be elongated in the vertical direction and to be parallel to adjacent ones. Also, the first electrodes 11 and the second electrodes 13 are arranged in an alternate manner in the horizontal direction and are spaced apart from adjacent ones by a certain distance.

[0039] The first electrode 11 and the second electrode 13 are electrically connected to a wiring member 25. 1 and is connected to the second electrode 13 or the first electrode 11 of another adjacent solar cell.

[0040] The wiring members 25 are arranged in a second direction, which is a horizontal direction intersecting with a first direction, which is a length direction of the electrodes (11, 13), in order to connect the solar cells (10a, 10b, 10c) in series with each other, and electrically connect two adjacent solar cells. The solar cells (10a-10c) may be connected in series or in parallel, but the following description will be given assuming that the solar cells (10a-10c) are connected in series.

[0041] Wiring member 25 includes first wiring member 21 and second wiring member 23. Taking second solar cell 10b disposed in the center as an example, first wiring member 21 can be electrically connected to first electrode 11 and insulated from second electrode 13, and second wiring member 23 can be electrically connected to second electrode 13 and insulated from first electrode 11.

[0042] Therefore, the first wiring member 21 is electrically connected to the first electrode 11 of the second solar cell 10b located in the center, and the other end is connected to the second electrode 13 of the third solar cell 10c. The second solar cell 10b and the third solar cell 10c are connected to each other. The second wiring member 23 is electrically connected to the second electrode 13 of the second solar cell 10b located in the center, and the other end is connected to the first electrode 11 of the first solar cell 10a, thereby connecting the second solar cell 10b and the first solar cell 10a.

[0043] The first wiring members 21 and second wiring members 23 are arranged alternately in the vertical direction, and are arranged so as to be parallel to adjacent ones.

[0044] In this manner, by arranging the wiring members 25 in a direction intersecting the electrodes (11, 13), it becomes easier to connect the wiring members 25 to the electrodes (11, 13), and it also becomes easier to align the electrodes (11, 13) and the wiring members 25. The first electrodes 11 and second electrodes 13 are all arranged parallel to the rear surface, and the wiring material 25 is connected in a direction that intersects with this, so that the thermal deformation direction of the wiring material 25 and the thermal deformation direction of the electrodes (11, 13) intersect, thereby protecting the solar cell from potential stress caused by thermal deformation.

[0045] Figure 2 shows a schematic cross-sectional view of the solar cell shown in Figure 1. As shown in Figure 2, in this embodiment, the solar cell forms a rear-contact structure in which both the first electrode 11 and the second electrode 13 are located on the rear surface of a semiconductor substrate 15 having a first conductivity type (e.g., p-type or n-type).

[0046] Thin films 16 and 17 are formed on the front surface of the semiconductor substrate 15, where light is incident, and on the rear surface, which is the opposite surface, of the semiconductor substrate 15, to prevent light reflection and provide passivation. .

[0047] Between the first electrode 11 and the semiconductor substrate 15, and between the second electrode 13 and the semiconductor substrate 15, an emitter 18 for lowering the potential barrier and a back surface field portion 19 are formed with a thin thickness, so that charges can be easily collected in the direction of the electrodes (11, 13).

[0048] Such solar cells have a square planar shape of 180 (mm) x 180 (mm) or less in width x length, and a very thin plate shape of 250 (μm) or less in thickness. Therefore, they are inevitably affected by thermal deformation, and in particular, because the first and second electrodes (11, 13) have a different thermal expansion coefficient from the semiconductor substrate 15, potential stress due to thermal deformation is inherent, which can lead to physical destruction or bending of the solar cell.

[0049] In this embodiment, the electrode width (wd) is increased compared to the conventional one, but the thickness (td) is relatively decreased to solve the problem of thermal deformation. Experimentally, the electrode width (wd) is formed between 100 μm and 600 μm, and the thickness (td) is formed between 0.1 μm and 10.0 μm, and the above-mentioned problem can be solved while stable charge collection is possible.

[0050] Fig. 3 shows the overall state of the wiring material in the solar cell module of Fig. 1, and Fig. 4 shows its cross-sectional state. As shown in Fig. 3 and Fig. 4, wiring material 25 is in the form of a thin rectangular belt. The cross-sectional state of wiring material 25 is rectangular, with a width (sd) of 1.0-50 mm and a thickness (Ad) of 25-200 μm.

[0051] When the wiring material 25 is connected to the electrodes (11, 13) and thermally deforms, the deformation force is transmitted to the solar cells (10a-10c), causing the solar cells (10a-10c) to deform. However, in this embodiment, the wiring material 25 is configured to have a reduced thickness to minimize thermal deformation, while having a wider width (sd) to improve charge transport.

[0052] The wiring material 25 has a cross-sectional appearance in which the coating layer 251 forming the surface coats the core layer 253 with a thin thickness of 15 μm-35 μm. The core layer 253 is made of a metal material with good conductivity such as Ni, Cu, Ag, or Al, and the coating layer 251 is made of Pb, Sn, or a solder having a chemical formula such as SnIn, SnBi, SnPb, Sn, SnCuAg, or SnCu, or a mixture of these.

[0053] FIG. 5 shows a wiring member according to another embodiment, and FIG. 6 shows its cross-sectional view. As shown in FIGS. 5 and 6, wiring member 25 according to this embodiment is in the form of a wire having a circular cross-section. Wiring member 35 according to this embodiment also includes coating layer 351 and core layer 353, and has a diameter between 250 μm and 500 μm. Thus, in this embodiment, since wiring member 25 has a circular cross-sectional shape, the problem of thermal deformation caused by wiring member 35 can be reduced more than that of the wiring member of FIG. 3.

[0054] Meanwhile, although FIGS. 3 and 5 show wiring material 25 with a rectangular cross section and a circular cross section, the cross section is not limited to this, and may be a polygon or a shape having a curved surface.

[0055] The wiring member 25 thus configured may further include a buffer portion 25a. Fig. 7 illustrates an example in which the buffer portion is formed on the strip-shaped wiring member as in Fig. 3 .

[0056] The buffer section 25a is configured to allow the wiring material to extend in the length direction, and may have any shape as long as it can be expanded, such as a twisted shape like a coil or a wrinkled shape with peaks and valleys, in which the actual length of the wiring material is longer than the width (Bwd) of the buffer section 25a. Figure 7 shows an example in which the buffer section 25a is wrinkled, and the length of the wiring material is longer than the width (Bwd) of the buffer section 25a.

[0057] Meanwhile, the width (Bwd) of the buffer portion 25a should be equal to or smaller than the spacing (fd) between the solar cells. As shown in FIG. 1, a plurality of solar cells are connected to each other by the wiring member 25 while maintaining a constant spacing (fd) between them. At this time, the buffer portion 25a is located between the solar cells, and even if the spacing between the solar cells connected to each other by the wiring member 25 increases, the buffer portion 25a may increase accordingly, and ultimately, the solar cell module can be protected from physical shocks such as the wiring member 25 being broken due to stress applied to the wiring member 25 or the portion where the wiring member 25 and the electrodes (11, 13) are connected being separated. Therefore, the width (Bwd) of the buffer portion 25a should be equal to or smaller than the spacing (fd) between the solar cells.

[0058] Hereinafter, the electrical connections between the electrodes of each solar cell and the wiring members in the solar cell module constructed in this manner will be described with reference to FIGS.

[0059] FIG. 8 is a simplified diagram showing the electrodes and wiring materials of each solar cell in the solar cell module shown in FIG. 1, as well as the connection relationships between them. FIG. 9 is a diagram showing a cross section taken along line I-I' in FIG. 8, and FIG. 10 is a diagram showing a cross section taken along line II-II' in FIG. 8.

[0060] Referring to this drawing, in each solar cell (10a-10c), the first electrode 11 and the second electrode 13 extend in parallel with the adjacent ones, and in the vertical direction (the y-axis direction of the drawing), The first electrodes 11 and the second electrodes 13 are arranged alternately.

[0061] The first wiring members 21 and second wiring members 23 also extend parallel to adjacent ones, and the first wiring members 21 and second wiring members 23 are arranged alternately in the horizontal direction (the x-axis direction in the drawing).

[0062] In this way, the first electrodes 11 and second electrodes 13 in each solar cell (10a-10c) are alternated, and the first wiring members 21 and second wiring members 23 are also arranged in an alternating manner. Meanwhile, the first electrodes 11 and second electrodes 13 collect charges of the first conductivity and the second conductivity that are opposite to each other, and the first wiring members 21 and second wiring members 23 also transmit charges that are different from each other. However, in this embodiment, the electrodes and wiring materials are all arranged in an alternating manner, so that charges can be collected and transferred in a balanced manner throughout each solar cell.

[0063] On the other hand, the first wiring member 21 is disposed across the second solar cell 10b and the third solar cell 10c. The second wiring member 23 is disposed across first solar cell 10a and second solar cell 10b to electrically connect them.

[0064] In each solar cell (10a-10c), a conductive layer 41 and an insulating layer 43 are located between the first wiring member 21 and the second wiring member 23, and between the first electrode 11 and the second electrode 13, to selectively connect or not electrically connect the wiring members and the electrodes.

[0065] The conductive layer 41 is made of epoxy-based or silicon-based synthetic resin containing conductive particles, and has adhesiveness and conductivity. The conductive particles may be Ni, Al, Ag, Cu, Pb, Sn, or a metal substance having a chemical formula such as SnIn, SnBi, SnPb, Sn, SnCuAg, or SnCu, or a mixture containing at least two of these. The conductive layer 41 may also be a tin alloy without synthetic resin, for example, a tin alloy having a chemical formula such as SnIn, SnBi, SnPb, Sn, SnCuAg, or SnCu.

[0066] The conductive layer 41 may also be made of solder paste. Solder paste is a paste containing solder particles containing lead (Pb) or tin (Sn). When heat is applied to the solder paste above its melting temperature, the solder particles in the solder paste melt and melt-bond the two base materials.

[0067] The conductive layer 41 is configured in this manner, and includes the first wiring member 21 / the second wiring member 23, and the first An electrical connection is established between the electrode 11 and the second electrode 13.

[0068] The insulating layer 43 is made of a synthetic resin such as an epoxy or silicon resin, or a ceramic. The first wiring member 21 and the first electrode 11 / the second wiring member 22 are formed of an adhesive insulating material such as a tack. 2 to prevent electrical connection between the electrodes 13.

[0069] In the second solar cell 10b, the conductive layer 41 is located in a first region (A1) where the first wiring member 21 and the first electrode 11 intersect, and in a second region (A2) where the second wiring member 23 and the second electrode 13 intersect, providing an electrical connection between them.

[0070] In the second solar cell 10b, the insulating layer 43 is located in a third region (A3) where the first wiring member 21 and the second electrode 13 intersect, and in a fourth region (A4) where the second wiring member 23 and the first electrode 11 intersect, to prevent electrical connection between them.

[0071] In addition, first wiring member 21 is electrically connected only to first electrode 11 from second solar cell 10b and is insulated from second electrode 13.

[0072] On the other hand, in the third solar cell 10c, the conductive layer 41 is formed such that the first wiring member 21 and the second electrode 13 are The insulating layer 43 is located in a fifth region (A5) where the first wiring member 21 and the first electrode 11 intersect, and the insulating layer 43 is located in a sixth region (A6) where the first wiring member 21 and the first electrode 11 intersect. Thus, in the third solar cell 10c, the first wiring member 21 is electrically connected only to the second electrode 13 and is insulated from the first electrode 13.

[0073] As a result, the first wiring material 21 is electrically connected only to the first electrode 11 from the second solar cell 10b, and is connected only to the second electrode 13 in the third solar cell 10c, electrically connecting the second solar cell 10b and the third solar cell 10c (see Figure 9).

[0074] In first solar cell 10a, conductive layer 41 is located in a seventh region (A7) where second wiring member 23 and first electrode 11 intersect, and insulating layer 43 is located in an eighth region (A8) where second wiring member 23 and second electrode 13 intersect. Thus, second wiring member 23 is electrically connected only to first electrode 11 from first solar cell 10a and is insulated from second electrode 13.

[0075] As a result, the second wiring material 23 is connected only to the second electrode 13 of the second solar cell 10b, and the first solar cell 10a is connected only to the first electrode 11, electrically connecting the second solar cell 10b and the first solar cell 10a (see FIG. 10).

[0076] In this way, the wiring members that are connected to and insulated from the electrodes by the conductive layer 41 and the insulating layer 43 are at least one first wiring member 21 and one second wiring member 23 based on one solar cell. A maximum of 20 first wiring members 21 and 20 second wiring members 23 are required, but this can be appropriately adjusted using variables such as the size of the solar cell, the size of the electrodes, and the size of the wiring members.

[0077] Furthermore, since the first wiring member 21 and the second wiring member 23 each connect two adjacent solar cells, such as the first and third solar cells (10a, 10c), in one solar cell, for example, the second solar cell 10b, the tip of the first wiring member 21 is located at the left end of the second solar cell 10b, and the tips of the second wiring member 23 are gathered at the opposite right end, and the number of wiring members 25 is half the total number of wiring members 25 arranged in each solar cell.

[0078] Figure 11 shows pad portion 14 formed at the intersection of electrodes (11, 13) and wiring material 25, and Figure 12 shows a cross section taken along line III-III' in Figure 11. The following description is based on second solar cell 10b.

[0079] As described above, conductive layer 41 is located at the connection points where the electrodes (11, 13) and wiring member 25 are electrically connected, electrically connecting first wiring member 21 and first electrode 11, and between second wiring member 23 and second electrode 13.

[0080] At non-connection points where the electrodes (11, 13) and wiring material 25 are not electrically connected, an insulating layer 43 is located to insulate between the first wiring material 21 and the second electrode 13, and between the second wiring material 23 and the first electrode 11.

[0081] Pad portion 14 is formed at each connection point of the multiple solar cells, and includes first pad portion 141 and second pad portion 143. Here, first pad portion 141 may be formed in a portion of first electrode 11 that is electrically connected to first wiring member 21 and first electrode 11 within a region where first wiring member 21 and first electrode 11 intersect, and may be formed in a portion of second electrode 13 that is electrically connected to second wiring member 23 and second electrode 13 within a region where second wiring member 23 and second electrode 13 intersect.

[0082] The pad portion 14 helps to ensure good electrical connection when the first and second electrodes (11, 13) and the wiring material 25 are connected by the conductive layer 41. When the charges collected by the electrodes (11, 13) are transferred to the wiring 25, the crossing area between the electrodes (11, 13) and the wiring 25 is increased to reduce the surface resistance, thereby reducing the loss of charges.

[0083] In this embodiment, the pad section 14 is formed of the same material as the electrodes (11, 13) and is configured as a part of the electrodes (11, 13), but is not limited to this. As an example, the pad section 14 may be formed of a different conductive material from the electrodes (11, 13) as illustrated in FIG. 13, or the conductive layer 41 may be configured as the pad section 14.

[0084] Pad portion 14 has a horizontal width (Pwa) smaller than the distance (Gwa) between first electrode 11 and second electrode 13, but larger than the line width (Gw) of the first and second electrodes (11, 13). In addition, pad portion 14 has a vertical width (Pwb) smaller than the distance (Wb) between first wiring member 21 and second wiring member 23, but larger than the line width (Bw) of wiring member 25.

[0085] If the width (Pwa) of pad portion 14 is larger than the distance (Gwa) between first electrode 11 and second electrode 13, adjacent electrodes may come into contact with each other due to pad portion 14, which may cause a problem of short circuit between them, and pad portion 14 cannot be formed unless it is larger than the line width (Gw) of the electrodes. Also, if the length (Pwb) of pad portion 14 is larger than the distance (Wb) between first wiring member 21 and second wiring member 23, it may come into contact with the pad formed on the adjacent electrode, which may also cause a problem of short circuit between two adjacent electrodes, and if it is not larger than the line width (Bw) of wiring member 25, the wiring member and the electrode can be stably connected.

[0086] FIG. 13 shows a cross-sectional view of the pad section 14', which is made up of electrodes and other layers. The pad section of the embodiment is different from the pad section 14 described above in that it is configured with an electrode on an electrode and another layer.

[0087] The pad portion 14' of this embodiment can be printed by a traditional screen printing method, an inkjet method, or the like. The pad portion 14' may be formed by a method such as a dispensing method, and may have a thickness of 1 μm to 20 μm. The pad portion 14' may be made of a metal such as Ni, Al, Ag, Cu, Pb, Sn, or a metal whose chemical formula is SnIn, SnBi, SnPb, Sn, SnCuAg, or SnCu, or a compound containing at least two of these metals. For example, the pad portion 14' may be made of the same material as the conductive layer 41.

[0088] In this embodiment, the pad portion 14' thus configured is located between the electrode 25 and the conductive layer 41 or the insulating layer 43, which has the effect of increasing the degree of freedom in design.

[0089] In other words, if the pad portion 14' does not exist or is configured as part of the electrode, the material constituting the conductive layer 41 or the insulating layer 43 must be selected based on the electrode 25, but the electrodes (11, 13) are already formed on the substrate, and it is not easy to change the material constituting the electrode.

[0090] In contrast, when the pad section 14' is composed of an electrode and other layers as in this embodiment, the material constituting the conductive layer 41 or the insulating layer 43 can be selected based on the pad section 14'. However, unlike the electrode, the pad section 14' is not formed on a substrate, so the material constituting the pad section 14' can be changed as necessary, and as a result, the range of materials to be selected for the conductive layer 41 or the insulating layer 43 can be expanded.

[0091] As an example, when the electrodes (11, 13) are made of Niv, if there is no pad portion 14', it is difficult to use solder made of tin or a tin alloy as the conductive layer material. However, if the pad portion 14' is made of one of Cu, Ag, and Au, it is possible to use solder made of tin or a tin alloy as the conductive layer material.

[0092] Fig. 14 shows a configuration in which the pad portion further includes a slit. As shown in Fig. 14, at least one of the first and second pad portions 14 can include a slit 145 formed as a narrow groove. The slits 145 are formed in the length direction of the wiring material 25, and a plurality of slits are formed symmetrically on the left and right sides based on the center line of the electrode 25. As a result, the overall appearance of the slits formed in the pad portion 14 is comb-shaped (Fig. 14(A)).

[0093] In the embodiment of FIG. 14, the slits 141 are formed in the length direction of the wiring material 25, but they may be formed in a diagonal direction as shown in (B), in a diamond shape as shown in (C), in a lattice shape as shown in (D), or in a pattern of a certain pattern. It is also possible for it to be formed without turns.

[0094] If the pad portion 14 is configured to further include a slit, when a conductive layer 41 is formed on the pad portion 14, the amount of coating can be increased, thereby improving the bonding strength and conductivity. Even if the electrode becomes larger due to the pad portion 14, the actual cross-sectional area can be maintained unchanged, preventing the recombination and loss of charges from the pad portion 14.

[0095] 15 and 16 show a configuration in which the size of the pad portion 14 varies depending on the position. FIG. 15 illustrates an example of selectively enlarging only one pad portion per line, while FIG. 16 illustrates an example of selectively enlarging only one pad portion per line.

[0096] In this embodiment, at least one of the pads 14 may have a different size from the remaining pads. More specifically, the first pad 141 or the second pad 143 may have a first contact pad 14a having a width larger than the widths of the first and second electrodes (11, 13), and may have at least one second contact pad 14b having a size larger than the first contact pad 14a. The size of the pad 14 is a concept that includes all cases where the two-dimensional area and the three-dimensional volume are different, and FIG. 15 shows a plan view of the electrode, showing a case where the bonding area where the wiring material 25 is electrically connected to the pad 14 via the conductive layer 41 is different.

[0097] In this embodiment, the second contact pad portion 14b has a larger area than the first contact pad portion 14a. A simple way to increase the area is to make the width (Pca) or the length (or length) (Pcb) of the second contact pad portion 14b larger than that of the first contact pad portion 14a. Fig. 15 shows that the width and length of the second contact pad portion 14b are both larger than the first contact pad portion 14a.

[0098] Meanwhile, in order to connect the electrodes (11, 13) to the pad portion 14, the entire solar cell must be exposed to high heat, which may cause a problem of the solar cell bending during the connection process. However, as in this embodiment, the size of the second contact pad portion 14b is configured to be larger than that of the first contact pad portion 14a, and the wiring material 25 is attached only to the second contact pad portion 14b first, and then the wiring material 25 is attached to the first contact pad portion 14a with a time lag, so that the solar cell is exposed to high temperatures with a time lag, thereby reducing the problem of the substrate bending. In addition, the contact resistance between the wiring 25 and the physical adhesive force of the first and second electrodes (11, 13) can be further improved through the second contact pad portion 14b.

[0099] In the manufacturing process, wiring material 25 is fixed by heat treatment while being raised onto the liquid conductive layer. However, since the conductive layer is liquid, wiring material 25 may warp during the heat treatment. However, this problem can be solved by first fixing the wiring material only to second contact pad portion 14b, and then fixing it to first contact pad portion 14a by heat treatment.

[0100] In this embodiment, the wiring material is heated to a temperature before the conductive layer and the insulating layer are hardened, temporarily fixed to the second contact pad portion 14b, and then the wiring material is heated to a temperature equal to or higher than the hardening temperature to connect the wiring material to the electrodes. Therefore, it is desirable that the number of second contact pad portions 14b required for temporary fixing is smaller than the number of first contact pad portions 14a.

[0101] FIG. 17 shows the state of the electrodes (11, 13) further including a broken portion 111.

[0102] As shown in FIG. 17, in the solar cell module of the present invention, at least a portion of the second electrode 13 insulated from the first wiring member 21, or at least a portion of the first electrode 11 insulated from the second wiring member 23, can include a broken portion 111 in which the electrode (11, 13) is partially disconnected.

[0103] In this embodiment, the broken portion 111 is a portion where the electrode (11, 13) is broken, and the electrode (11, 13) is absent for a certain width (Cw) in the longitudinal direction of the electrode (11, 13).

[0104] Such disconnected portions 111 are formed along the non-connected points, and include a first disconnected portion 111a and a second disconnected portion 111b. The first disconnected portion 111a is formed at each non-connected point in the first electrode 11, and the second disconnected portion 111b is formed at each non-connected point in the second electrode 13.

[0105] The disconnection portion 111 cuts off physical contact between the electrodes (11, 13) and the wiring material 25 at the non-connection point, and basically cuts off the electrical connection between them. The width (Cw) of such a disconnection portion must be at least larger than the line width (Bw) of the wiring material 25.

[0106] Disconnected portion 111 is formed at a non-connected point where the electrode is not connected to the wiring material, so even if electrode 111 includes a disconnected portion in this way, it does not affect the efficiency of the solar cell.

[0107] In this way, when the electrodes (11, 13) are formed to include the disconnected portion 111, the electrodes (11, 13) and the wiring material 25 are not physically connected, eliminating the need to place an insulating layer 43 at each non-connected point, thereby increasing the work yield while correspondingly reducing manufacturing costs.

[0108] FIG. 17 shows an example in which breaks 111 exist in both second electrode 13 insulated from first wiring member 21 and first electrode 11 insulated from second wiring member 23. However, such breaks 111 may exist only in a part of second electrode 13 insulated from first wiring member 21 and a part of first electrode 11 insulated from second wiring member 23. Alternatively, an insulating layer 43 may exist in the remaining part, and the insulating layer 43 may insulate first wiring member 21 from second electrode 13 and insulate second wiring member 23 from first electrode 11.

[0109] FIG. 18 is a diagram showing how the width of the broken portion varies depending on the position.

[0110] In Figure 18, the electrodes (11, 13) belonging to the first group (G1) are arranged adjacent to the left side (LL) of the solar cell in the longitudinal direction of the wiring material 25 of one solar cell, the electrodes (11, 13) belonging to the second group (G2) are arranged on the right side (RL), and the third group (G3) illustrates electrodes (11, 13) arranged in the center of the solar cell between the first group (G1) and the second group (G2).

[0111] In this embodiment, the broken portion 111 includes a first long broken portion 113 formed in an electrode (11, 13) belonging to the first group (G1), a second long broken portion 115 in the second group (G2), and a short broken portion 117 in the third group (G3).

[0112] First, in first long broken portion 113, the electrodes are separated by a first distance (Da1) in the length direction of the electrodes, in second long broken portion 115, by a second distance (Da2), and in short broken portion 117, by a third distance (Da3). Comparing first distance (Da1) and second distance (Da2), it is desirable that they are the same, but they are at least greater than third distance (Da3). In addition, third distance (Da3) is at least greater than the line width of wiring member 25, and first distance (Da1) and second distance (Da2) are smaller than the distance between first wiring member 21 and second wiring member 23.

[0113] In this way, since the break portion 111 includes the first long break portion 113, the second long break portion 115, and the short break portion 117, which have incorrect spacing depending on the position, when the wiring material 25 is fixed to the solar cells (10a-10c) due to the margin corresponding to the difference between the first distance (Da1) and the third distance (Da3), it is possible to prevent the wiring material from shifting and the wiring material coming into contact with the electrodes at the non-connected points, thereby preventing a problem of a short circuit.

[0114] Fig. 19 is a diagram showing a state of a broken portion including a bank, and Fig. 20 is a diagram showing a cross section cut along line IV-IV' in Fig. 19. In this embodiment, bank 51 means an insulating material that selectively wraps the end of electrode (11, 13) in electrode (11, 13) including broken portion 111, and includes first bank 51a and second bank 51b. First bank 51a and second bank 51b are divided into upper and lower islands based on wiring material 25. First bank 51a is arranged on the upper side based on wiring material 25, and second bank 51b is arranged on the lower side.

[0115] The paired banks 51 are located at the ends of the electrodes forming the disconnection portion 111 and have a cross-sectional appearance that wraps around the ends. This allows the wiring material 25 that crosses the disconnection portion 111 to be placed between the first bank 51a and the second bank 51b, preventing the wiring material 25 from coming into physical contact with the electrodes (11, 13) due to misalignment or the like.

[0116] The bank 51 should have a horizontal width (Bhw) larger than the line width (Gw) of the electrodes (11, 13) and smaller than the distance (Gwa) between the electrodes. Also, the vertical width (Bvw) should be smaller than the distance (Wb) between the wiring materials. do.

[0117] If the horizontal width (Bhw) of the bank 51 is larger than the line width (Gw) of the electrodes (11, 13), the bank 51 can wrap around the electrodes (11, 13) in the horizontal direction to prevent physical contact between the wiring material 25 and the electrodes (11, 13). If the horizontal width (Bhw) of the bank 51 is larger than the distance (Gwa) between the electrodes, the bank 51 can also be formed on the pad portion 14 adjacent to the break portion 111 in the vertical direction, thereby preventing physical contact between the pad portion 14 and the wiring material 25 at the connection point.

[0118] The bank 51 thus configured can be made of the same material as the insulating layer 43 or can be made of another material. Although a rectangular planar shape of the bank 51 is shown as an example, the shape is not limited to a circular or elliptical shape.

[0119] FIG. 21 is a diagram showing a connection electrode portion for electrically connecting pad portions 14, and FIG. 22 is a diagram showing a cross-sectional state along line VV' in FIG.

[0120] In this embodiment, the first electrode 11 includes a first pad portion 141 and a first disconnected portion 111a, and the second electrode 13 includes a second pad portion 143 and a second disconnected portion 111b.

[0121] In this embodiment, the connection electrode portion 61 is formed long in the horizontal direction (the y-axis direction in the drawing) and is positioned so as to overlap with the wiring material 25. This connection electrode 61 can be formed in the same process as the electrodes (11, 13), or it can be separated from the electrodes (11, 13) and formed in a different process. If the connection electrode 61 is formed in the same process as the electrodes, the connection electrode 61 and the electrodes are made of the same material, reducing the number of work steps, and if formed in a different process, the connection electrode and the electrodes can be made of different materials, increasing the range of materials to be selected for forming the connection electrode with the electrodes.

[0122] If the connection electrode portion 61 is formed like the electrodes (11, 13), it can be made of the same material as the electrodes (11, 13), or if it is formed in a different process, it can be made of a different material.

[0123] The connection electrode portion 61 includes a first connection electrode 61a and a second connection electrode 61b. The first connection electrode 61a physically and electrically connects the first pad portions 141 of the adjacent first electrodes 11 across a second disconnection portion 111b provided on the second electrode 13. Similarly, the second connection electrode 61b connects the second pad portions 143 of the adjacent second electrodes 13 across a first disconnection portion 111a provided on the first electrode 11.

[0124] The first connection electrode 61a and the second connection electrode 61b are arranged in parallel with each other at a constant distance (Cdd) between them. The distance (Cdd) between the first connection electrode 61a and the second connection electrode 61b is substantially the same as the distance (Wb) between the first wiring member 21 and the second wiring member 23.

[0125] Since wiring 25 is located on such connection electrode 61 , it is preferable that the line width (Cwd) of connection electrode 61 is equal to or larger than the line width (Bw) of wiring 25 , and is smaller than the vertical width of pad 14 .

[0126] Second wiring member 23 is located on first connection electrode 61a, and first wiring member 11 is located on second connection electrode 61b.

[0127] A conductive layer 41 is located between the connection electrode 61 and the wiring 25 to provide a good connection between them. Optionally, the conductive layer 41 can be omitted, in which case the wiring 25 is soldered directly to the connection electrode 61. Optionally, a solder paste can also be used to provide the connection between the two.

[0128] Hereinafter, a method for manufacturing such a solar cell module will be described with reference to FIG.

[0129] In step S11, insulating adhesive is applied to form an insulating layer at each disconnected point. The insulating adhesive is a viscous liquid material that is made of epoxy or silicone synthetic resin as the main ingredient, mixed with hardeners, fillers, reinforcing agents, etc. The insulating adhesive can be applied to the non-connected points using well-known techniques such as screen printing, inkjet, and dispensing.

[0130] This insulating adhesive is applied in an island shape to the non-connection points of wiring material 25 so that wiring material 25 is not connected to either first electrode 11 or second electrode 13, as in the pattern shown in FIG.

[0131] In the process temperature conditions, the curing temperature varies depending on the material of the insulating adhesive, and the melting temperature at which the insulating adhesive melts after curing must be higher than the curing temperature of the conductive adhesive and wiring material. Preferably, the curing temperature of the insulating adhesive is higher than 210 degrees Celsius and lower than 250 degrees Celsius, and the melting temperature is 400 degrees Celsius or higher.

[0132] After the insulating adhesive is applied, it is exposed to a temperature equal to or higher than its curing temperature to cure the insulating adhesive and form an insulating layer.

[0133] This step (S11) can be omitted depending on the configuration of the solar cell module. For example, in the embodiment of the solar cell module described above, in which the electrodes (11, 13) include a disconnection portion, the insulating layer 43 is not required, and therefore, in this embodiment, this step (S11) is omitted.

[0134] In step S12, conductive adhesive is used to form a conductive layer at each connection point. The conductive adhesive is a viscous liquid made of epoxy or silicon-based synthetic resin as the main ingredient, mixed with hardeners, fillers, and reinforcing agents, and further contains conductive particles. The conductive particles are Ni, Al, Ag, Cu, Pb, Sn, or metal materials with chemical formulas such as SnIn, SnBi, SnPb, Sn, SnCuAg, and SnCu, or mixtures containing at least two of these. The conductive adhesive can also be solder paste. Solder paste is a paste containing solder particles containing lead (Pb) or tin (Sn). When heated above the melting temperature, the solder particles in the solder paste melt and melt and bond both base materials.

[0135] Similarly, the conductive adhesive can be applied to the connection points by well known techniques such as screen printing, ink jet, or dispensing.

[0136] This conductive adhesive is applied in an island shape to the connection points so that the wiring material 25 is connected to either the first electrode 11 or the second electrode 13, as in the pattern shown in FIG.

[0137] Regarding the process temperature conditions, the curing temperature varies depending on the material constituting the conductive adhesive, as with the insulating adhesive, but must be at least lower than the melting temperature of the insulating layer 43. Also, the melting temperature at which the conductive adhesive melts after curing must be higher than the curing temperature of the wiring material.

[0138] Preferably, the curing temperature of the conductive adhesive is the same as the lamination temperature in step S15. In this way, when the curing temperature of the conductive adhesive is the same as the lamination temperature in step S15, the conductive adhesive is not cured immediately after being applied, but can be cured in step S15, which reduces the number of processes and reduces the possibility of thermal deformation since the solar cell is not exposed to high temperatures multiple times.

[0139] Furthermore, if the curing temperature of the insulating adhesive is also the same as the lamination temperature, the insulating adhesive can be cured in step S15 together with the conductive adhesive without curing in step S11, thereby reducing the need for two curing processes (insulating adhesive and conductive adhesive).

[0140] If the curing temperature of the conductive adhesive is different from the lamination temperature, the conductive adhesive is applied and then subsequently exposed to a curing temperature to form the conductive layer.

[0141] Next, in step S13, the first wiring members 21 and the second wiring members 23 are loaded. The first wiring members 21 and the second wiring members 23 are arranged in a manner that connects two adjacent solar cells to each other in the length direction, as illustrated in Fig. 8, and the first wiring members 21 and the second wiring members 23 are alternately arranged in a direction intersecting the length direction.

[0142] Next, in step S14, tape is used to fix the loaded first wiring member 21 and second wiring member 23 so that they do not move. In this step (S14), a liquid tape in which a liquid material is applied, and a solid tape in which an adhesive is applied to a film are used. The liquid tape is formed by applying a liquid material onto the first wiring member 21 and the second wiring member 23 with a dispenser and then immediately irradiating the liquid material with UV light to harden it, or the liquid material can be applied by a method such as screen printing or inkjet printing and then thermally hardened to form the liquid tape. The liquid material may be an epoxy-based or silicone-based synthetic resin.

[0143] The tape is attached in a direction intersecting the wiring 25 so as to facilitate fixing of the wiring 25, and may be in any form that can fix the wiring 25. As one example, tape may be attached to the entire rear surface of the solar cell where the wiring is located to protect the solar cell from moisture, or if either the conductive adhesive or the insulating adhesive has not hardened, the tape may be attached in such a way that some of the adhesive is exposed.

[0144] On the other hand, the wiring material 25 may be temporarily fixed at a curing temperature, for example 90 degrees Celsius to 120 degrees Celsius, before at least one of the conductive adhesive and the insulating adhesive is cured, in which case this step (S14) is omitted.

[0145] In step S15, the encapsulant and transparent substrate are placed on the modularized solar cell as described above, and the encapsulant and back sheet are placed underneath, and then these are packaged by thermocompression in a laminating device. The heat treatment temperature is 145 to 165 degrees Celsius. At this time, the electrodes are all fixed with tape while laminating, so the problem of electrode distortion during the lamination process can be prevented.

[0146] Hereinafter, an embodiment in which the solar cell further includes a dispersion layer will be described with reference to Figures 24 to 28. The embodiment described below will be described as including a dispersion layer only in some of the above-mentioned embodiments, but can be similarly applied to other embodiments not described.

[0147] FIG. 24 shows how a dispersion layer is disposed between a conductive layer and an insulating layer, and FIG. 25 is a cross-sectional view taken along line VI-VI' in FIG.

[0148] As shown in FIGS. 24 and 25, first electrodes 11 and second electrodes 13 are arranged alternately in the horizontal direction, and first wiring members 21 and second wiring members 23 are arranged alternately in the vertical direction.

[0149] Conductive layers 41 and insulating layers 43 are located along each of the connection points and non-connection points, and selectively connect or insulate the wiring material 25 and the electrodes (11, 13) at the intersections.

[0150] The dispersion layer 45 is laterally located between the conductive layer 41 and the insulating layer 43 and is formed separately therefrom to attach the wiring material 25 to the substrate. Preferably, the dispersion layer 45 is formed between each conductive layer 41 and the insulating layer 43, but may be selectively formed as required.

[0151] Since this dispersion layer 45 is formed between the intersections where the conductive layer 41 and the insulating layer 43 are formed, the width (Sph) should be smaller than the distance (Gwa) between the first electrode 11 and the second electrode so that the conductive layer 41 or the insulating layer 43 can be formed normally at the intersections.

[0152] Although the figure shows the vertical width (Spv) as being larger than the line width (Bw) of the wiring material 25, at least the vertical width (Spv) of the dispersion layer 45 should be larger than the line width of the wiring material 25 in this manner in order for the wiring material 25 to be stably attached to the substrate.

[0153] In a preferred example, the dispersion layer 45 can be formed of the same material as the conductive layer 41 or the insulating layer 43. The dispersion layer 45 can also be formed of the same material as the electrodes (11, 13).

[0154] In consideration of the manufacturing process, it is preferable that the dispersion layer 45 is formed simultaneously with the conductive layer 41. When the dispersion layer 45 is formed of the same material as the conductive layer 41, the dispersion layer 45 can be formed without adding a new process.

[0155] When the dispersion layer 45 is formed on the insulating layer 43, the dispersion layer 45 is located between the first electrode 11 and the second electrode 13, which collect different conductive charges. Therefore, when the dispersion layer 45 is formed from a conductive material, there is a risk of short circuiting. However, when the dispersion layer 45 is formed on the insulating layer 43, the dispersion layer 45 can be formed without these risks.

[0156] Meanwhile, it is desirable that the dispersion layer 45 thus formed has a larger coating area per wire than the conductive layer 41 or the insulating layer 43. The stress propagated from the wiring 25 breaks the physical bond between the electrode and the wiring as it propagates to the intersections, but if the coating area of ​​the dispersion layer 45 is larger than that of the conductive layer 41 or the insulating layer 43, the stress is propagated more to the dispersion layer 45 than to the intersections. Therefore, the stress propagated to the conductive layer 41 or the insulating layer 43 is reduced compared to before, and the above-mentioned problems can be alleviated.

[0157] FIG. 26 shows how a dispersion layer is formed when an electrode includes a broken portion, and FIG. 27 shows a cross-sectional view taken along line VII-VII' in FIG.

[0158] In the disconnection portion 111 as shown in FIGS. 26 and 27, the electrodes (11, 13) are disconnected, and the electrodes (11, 13) are missing for a certain width (Cw) in the longitudinal direction of the electrodes (11, 13).

[0159] Such disconnected portions 111 are formed along the non-connected points, and include a first disconnected portion 111a and a second disconnected portion 111b. The first disconnected portion 111a is formed for each non-connected point of the first electrode 11, and the second disconnected portion 111b is formed for each non-connected point of the second electrode 13.

[0160] A conductive layer 41 is located along the connection point to electrically connect the wiring material and the electrode.

[0161] In this embodiment, dispersion layer 45 is formed long in the length direction of wiring member 25 at the non-connection point where disconnection portion 111 is formed, and adheres wiring member 25 to the substrate.

[0162] By forming the dispersion layer 45 in this manner at the broken portion 111, the dispersion layer 45 is located between adjacent conductive layers 41 in the length direction of the wiring 25. Therefore, the horizontal width (Sph) of the dispersion layer 45 should be smaller than the distance between the first electrodes 11 and 11 or the distance between the second electrodes 13 and 13 which form connection points with the wiring 25. And, the vertical width (Spv) of the dispersion layer 45 should be larger than the line width of the wiring 25 so that the wiring 25 can be stably attached to the substrate.

[0163] FIG. 28 shows an example in which a plurality of dispersion layers are formed. In FIG. 27, the dispersion layer 45 is The figure shows the first to third dispersion layers (45a-45c) as an example in which the first to third dispersion layers (45a-45c) are all the same size, but the sizes can be different depending on the selection.

[0164] Hereinafter, a solar cell module made using solar cells of a conventional structure in which the first electrode and the second electrode are located on the front and rear surfaces of the substrate, respectively, will be described. Although there are differences in the structure of the solar cell compared to the above-mentioned embodiment, the fact that it includes a pad part and the size of the pad part is different is the same as the above-mentioned embodiment, and the technical idea is the same.

[0165] FIG. 29 is a perspective view showing the overall state of a solar cell module which is a solar cell of a conventional structure, FIG. 30 is a cross-sectional view taken along the line XI-XI' in FIG. 29, and FIG. FIG. 32 is a cross-sectional view taken along the line XII-XII′ in FIG. 29 , and FIG. 33 is a cross-sectional view taken along the line XII-XII′ in FIG. Shows.

[0166] 29 to 32, in the solar cell module of this embodiment, multiple solar cells arranged adjacent to each other are connected by multiple thin wiring members 125. Of the two adjacent solar cells, the wiring members 125 are electrically connected to a first electrode 113 formed on the front surface of a first solar cell (C1), and are also connected to a second electrode 115 formed on the rear surface of a second solar cell C2 adjacent to the first solar cell (C1).

[0167] The solar cell has a thin cubic shape, with horizontal and vertical dimensions of approximately 156 (mm)*156 (mm), and a thickness of 150 (μm)-200 (μm).

[0168] A first electrode 113 is located on the front surface, which is the surface where light is incident, and is connected to a wiring material 125. The first electrode 113 collects charges of opposite conductivity to that of the semiconductor substrate 111. In one example, if the semiconductor substrate 111 is a p-type semiconductor substrate, the first electrode 113 collects electrons.

[0169] The semiconductor substrate 111 forms a pn junction, and is made of an n-type or p-type semiconductor substrate containing a first conductive impurity.

[0170] A second electrode 115 is formed on the rear surface of the semiconductor substrate 111 in a direction intersecting with the first electrode 113. The second electrode 115 collects charges of opposite conductivity to the first electrode 113.

[0171] Between the semiconductor substrate 111 and the first electrode 113, and between the second electrode 115, there are an emitter layer and a back surface field portion that lower the potential barrier, and a passivation film that prevents charges from recombining from the surface, but this configuration has been omitted in the figure.

[0172] In the solar cell having such a configuration, two adjacent solar cells are connected by a plurality of wiring members 125 .

[0173] The number of such wiring members 125 may be 30 or less and 60 or more, and each wiring member 125 is in the form of a wire having a circular cross section as shown in (A) of Fig. 32. (B) in Fig. 32 shows the cross-sectional shape of wiring member 125.

[0174] As shown in the figure, the wiring material 125 has a cross-sectional view in which the coating layer 125a coats the core layer 125b with a thin thickness, for example, 12 (μm), and has an overall area of ​​250 (μm). The thickness is 500 (μm).

[0175] The core layer 125b is made of a metal having good conductivity such as Ni, Cu, Ag, or Al, and the coating layer 125a includes a metal material having a chemical formula such as Pb, Sn, SnIn, SnBi, SnPb, Sn, SnCuAg, or SnCu, particularly a solder, and can be physically and electrically connected to other metals through soldering.

[0176] When connecting two adjacent solar cells, for example, 10-15 pieces of wiring material 125 may be used when the semiconductor substrate is 156 (mm) x 156 (mm) in size, but the number of wiring materials 125 may vary depending on the size of the semiconductor substrate and the line width, thickness, pitch, etc. of the electrodes.

[0177] Although the above description is based on the fact that the lead 125 is in the form of a wire having a circular cross section, the cross section may have various shapes such as a rectangle or an oval.

[0178] Such wiring material 125 connects two adjacent solar cells, one connected to the first electrode 1130 of the first solar cell (C1) and the other connected to the second electrode 1150 of the second solar cell C2. A preferred mode of connecting electrodes and wiring material is soldering, which melts and bonds materials.

[0179] In this embodiment, at least a portion of the first electrode 113 may have a plurality of first pad portions 140 formed in the area where the first electrode 113 intersects with the wiring material 125, the first pad portions 140 having a width (w1) larger than the line width of the first electrode 1130.

[0180] The first pad portion 140 widens the area where the first electrode 1130 and the wiring 125 cross, thereby reducing the contact resistance when the wiring 125 is connected to the first electrode 1130, and increasing the physical bonding strength between the wiring 125 and the first electrode 1130. In this case, the width of the first electrode 1130 can be widened, or another electrode layer can be additionally formed.

[0181] Furthermore, in order to further improve the physical bonding strength and contact resistance while minimizing the banding of the semiconductor substrate with the wiring material 125, at least one pad portion of the first pad portion 140 may be different in size from the remaining pad portions. Here, the different sizes of the pad portions means that at least one of the widths or lengths of the pad portions is different. Therefore, the first pad portion 140 may include at least one pad portion having a different width or length. This will be described later.

[0182] The number of the first pad parts 140 may be six or more and may be less than the number of the first electrodes 113 .

[0183] Furthermore, taking into consideration the shading area where light is blocked by each of the first pad portions 140, the physical bonding force, and the contact resistance, the width (w1) of each of the first pad portions 140 may be greater than the line width of the first electrode 1130 and less than 2.5 mm, and the length of each may be greater than the line width of the first electrode 1130 and less than 30 mm.

[0184] In one example of a soldering method, the wiring 125 is placed on the front and rear surfaces of two adjacent solar cells, facing the first electrode 113 and the second electrode 115, respectively, and in this state, the coating layer 125a of the wiring 125 is heated to a temperature above its melting point for several seconds. As a result, the coating layer 125a melts and cools, the wiring 125 is attached to the electrodes.

[0185] In an alternative example, the wiring material 125 can be attached to the electrode with a conductive adhesive. The conductive adhesive is a material such as an epoxy-based synthetic resin or a silicon-based synthetic resin with Ni, A. It is a material that contains conductive particles represented as lead, Ag, Cu, Pb, Sn, SnIn, SnBi, SnPb, Sn, SnCuAg, and SnCu, and is a material that is liquid and thermoset when heat is applied. The wiring material 125 can also be attached with solder paste. Solder paste is a paste that contains solder particles containing lead (Pb) or tin (Sn), and when heat is applied above the melting temperature, the solder particles in the solder paste melt and melt and bond the two base materials.

[0186] Various aspects of the first electrode will be described below with reference to FIGS.

[0187] FIG. 33 shows the state of the first electrode in the first embodiment among various embodiments.

[0188] In FIG. 33, the first electrode 1130 includes a collecting electrode 1131 and a connecting electrode 1133 .

[0189] The collecting electrodes 1131 have a certain width, extend long in one direction, and are arranged parallel to adjacent ones to form a stripe array. The collecting electrodes 1131 have a width of 30 μm-100 μm, a thickness of 15 μm-30 μm, and a pitch (P1), which is the distance between electrodes, of 1.2 mm-2.2 mm.

[0190] The connection electrodes 1133 also have a constant line width, and extend long in a direction intersecting with the collecting electrodes 1131 to electrically and physically connect the collecting electrodes 1131 .

[0191] This connecting electrode 1133 is substantially the same as or wider than the collecting electrode 1131, having a line width of 75 μm-120 μm smaller than that of the first pad portion 140, and a thickness of 15 μm-30 μm, but the pitch (P2) is 5 mm-23 mm, which is larger than the pitch (P1) of the collecting electrode 1131 and is less than 10 times smaller.

[0192] Alternatively, the connection electrode 1133 may have a line width larger than that of the collecting electrode 1131 and may be equal to or smaller than the lateral width (w 1 ) of the first pad portion 140 .

[0193] At the point where the collecting electrode 1131 and the connecting electrode 1133 intersect, a first pad portion 140 is selectively formed.

[0194] As in the above-described embodiment, the first pad section 140 is configured to form an area where the electrode meets the wiring member 125, thereby enabling good coupling between the wiring member 125 and the electrode. It is preferable to form the first pad section 140 at every intersection, but it is also possible to selectively form the first pad section 140 only at even-numbered columns or odd-numbered columns, or to form the first pad section 140 in different rows according to a certain rule, and it is also possible to selectively form the first pad section 140 at every intersection or to arrange them randomly.

[0195] The number of the first pad units 140 is determined taking into consideration variables such as size, electrode thickness, pitch, etc. In this embodiment, the first pad units 140 are formed at all intersections of every sixth row.

[0196] Experimental results showed that when the collecting electrode 1131, the connecting electrode 1133, and the first pad portion 140 were fabricated within the ranges described in this specification, the solar cell showed the most ideal efficiency, and when any one of them was outside the ranges described, the desired efficiency was not achieved.

[0197] The collecting electrode 1131, the connecting electrode 1133, and the first pad portion 140 thus configured can be simultaneously formed by a screen printing method, in which case they are all made of the same material, for example, silver (Ag). Also, each component can be individually configured as necessary.

[0198] Wiring 125 is located directly above connection electrode 1133, and is formed long in a direction parallel to the connection electrode. Therefore, wiring 125 and connection electrode 1133 are arranged to face each other. Wiring 125 has a line width (Da) of 250 (μm) to 500 (μm).

[0199] Since the wiring material 125 is soldered while positioned on the connection electrode 1133 in this manner, it is fused and bonded not only to the first pad portion 140 but also to the connection electrode 1133, thereby reducing the contact resistance between the electrode and the wiring material, increasing the efficiency of the cell, and also increasing the bonding strength of the wiring material.

[0200] On the other hand, the collecting electrode 1131 may be configured to further include a disconnection portion 114 as in the second embodiment illustrated in Fig. 34. The disconnection portion 114 is a portion where the electrode is cut, and the collecting electrode 1131 has no electrode for a certain width (Cw) in its extension direction. Here, "Cw" refers to the width (Cw) of the disconnection portion 114 that may be formed at 1.5-1.8 mm when the pitch of the connecting electrodes 1133 is 10-14 mm, but the width (Cw) of the disconnection portion 114 can vary within the range of 1.5 to 3.2 mm.

[0201] In this embodiment, the disconnection portion 114 is formed every two rows, but can be changed in various ways depending on the selection. For example, the disconnection portion 114 can be formed every row, every third row, or randomly. In addition, in this embodiment, the disconnection portion 114 is formed between the connection electrodes, but can be formed in various positions depending on the selection.

[0202] In this embodiment, a connection electrode is connected between first pad portions 140 and wiring material 125 is soldered thereon, so there is no problem of reduced efficiency of the solar cell due to broken wire portion 114. Instead, by including broken wire portion 114 in first electrode 113, it is possible to reduce manufacturing costs.

[0203] FIG. 35 shows a pad portion 140 and an assistant pad portion 141 between the pad portions. 4 shows a first electrode of a further formed third embodiment.

[0204] As shown in FIG. 35, in the solar cell module according to the present invention, among a plurality of first pad portions 140 provided on each solar cell, at least one pad portion may be different in size from the remaining pad portions.

[0205] Here, at least one of the pad portions may be, for example, an auxiliary pad portion 141 having a relatively small size as shown in Fig. 35. In addition, the remaining pad portions may be pad portions 140 having a relatively large size compared to the auxiliary pad portion.

[0206] Therefore, the auxiliary pad portion 141 has a width or length smaller than the width or length of the pad portion 140 and is formed at an intersection located vertically between the first pad portions 140 to connect the wiring material 125 and the connection electrode 1133.

[0207] The auxiliary pad portion 141 may be made of the same material as the first pad portion 140, or may be made of a conductive adhesive made of an adhesive resin containing conductive metal particles.

[0208] It is desirable that the width (w2) of auxiliary pad portion 141 is equal to or smaller than the line width (Da) of wiring material 125.

[0209] Similar to the first pad portion 140, the size of the auxiliary pad portion 141 is also appropriately adjusted in consideration of various variables.

[0210] In FIG. 35, the auxiliary pad portions 141 are shown as being formed every two rows between the first pad portions 140, but it is also possible to form them in various shapes, such as being formed in every row or in triplicates.

[0211] Fig. 36 shows another example of the auxiliary pad unit 142 as the fourth embodiment. The only difference is that the auxiliary pad unit 141' shown in Fig. 35 is formed at an intersection, but the auxiliary pad unit 142 in Fig. 36 connects the collecting electrodes 1131 of two adjacent lines.

[0212] 36 has a smaller horizontal width (w3) than the first pad portion 140, but a larger vertical width (w4') than the first pad portion 140. Therefore, the contact area between the wiring 125 and the first electrode 1130 can be further increased, thereby reducing the contact resistance and increasing the bonding strength.

[0213] FIG. 37 is a diagram showing a part of a first electrode according to a fifth embodiment of the front electrode.

[0214] In this embodiment, the first electrode 1130 includes a ladder electrode 1135 and a wiring electrode 1137 .

[0215] The ladder electrode 1135 has a ladder shape including a pair of legs 1135a and a connection portion 1135b connecting between the legs 1135a.

[0216] The legs 1135a are spaced apart from each other by a certain distance (SA) and are formed long in the same direction as the extension direction of the lead 125. The distance (SA) between the legs is smaller than the pitch (PD) of the lead but larger than the width (w1) of the first pad portion 140. Preferably, the distance (SA) is 0.3 to 0.7 compared to the pitch (PD) of the lead.

[0217] The connecting portion 1135b connects between the pair of legs 1135a in a direction intersecting the legs 1135a. The connecting portions 1135b are spaced apart from each other by a fixed distance (S1), and the width (S1) is 1.3 mm to 1.9 mm.

[0218] The legs 1135a and connecting portions 1135b thus constituting the ladder electrode 1135 have a line width of 30 μm-120 μm, similar to the width of the collecting or connecting electrodes.

[0219] The wiring electrode 1137 electrically connects two adjacent ladder electrodes 1135 in a direction intersecting the ladder electrodes 1135. Like the ladder electrodes 1135, the wiring electrode 1137 has a line width of 30 μm to 120 μm.

[0220] Meanwhile, wiring material 125 is located along the center of ladder electrode 1135 and is connected to ladder electrode 1135. First pad portion 140 is selectively located at a position facing wiring material 125, and extension electrode 144 connects between first pad portion 140 and first pad portion 140.

[0221] The first pad section 140 is the same as that in the first embodiment described above, and therefore a detailed description thereof will be omitted here.

[0222] The line width (w4) of the extended electrode 144 is equal to or smaller than the width (w1) of the first pad portion 140, equal to or larger than the line width of the leg portions 1135a or the connection portions 1135b of the ladder electrode 1135, and smaller than the distance (SA) between the legs 1135a. The extended electrode 144 faces the wiring 125, and is a portion that is melted and bonded to the wiring 125 when the wiring 125 is soldered to the first electrode 1130. Therefore, when the extended electrode 144 is disposed in such a manner in the portion where the wiring 125 and the first electrode 1130 face each other, the area where the wiring 125 and the first electrode 1130 are bonded is increased, thereby increasing the bonding force and reducing the contact resistance.

[0223] In this embodiment, the ladder electrode 1135, the wiring electrode 1137, the first pad portion 140, and the extension electrode 144 can all be made simultaneously by screen printing. In this case, they are all made of the same metal material, for example, silver (Ag). Alternatively, these components can be formed in separate processes.

[0224] 38 and 39 show a state in which an auxiliary pad portion is formed between pad portions instead of the extended electrode 144. The only difference compared to FIG. 37 is that an auxiliary pad portion (141, 142) is located between the first pad portion 140 instead of the extended electrode 144 connecting the pad portions.

[0225] Similarly, the auxiliary pad portion 141 can increase the contact area with the wiring material 125, thereby decreasing the contact resistance and increasing the bonding strength. Also, since the auxiliary pad portion 141 is formed to have a smaller area than the extended electrode 144, it is expected to reduce the manufacturing cost.

[0226] The auxiliary pad portions 141 and 142 are the same as those in the previous embodiment, and therefore a detailed description thereof will be omitted here.

[0227] FIG. 40 shows a first electrode in which the first pad portion includes an extended pad portion 140e having a first size and an auxiliary pad portion 140a having a second size smaller than the first size.

[0228] In this embodiment, the first electrode 1130 includes a collecting electrode 1131 and a connecting electrode 1133 as previously described.

[0229] The first pad portions 140 may selectively include an extended pad portion 140e and an auxiliary pad portion 140a at positions where the lead 125 passes among the intersections of the collecting electrodes 1131 and the connecting electrodes 1133.

[0230] Here, the auxiliary pad portion 140a of the first pad portion 140 may have a first size, and the expansion pad portion 140e may have a second size larger than the first size. That is, the width and length of the expansion pad portion 140e may be larger than the width and length of the auxiliary pad portion 140a.

[0231] The auxiliary pad portion 140a may be located between a pair of the extended pad portions 140e in the longitudinal direction of the wiring material.

[0232] More specifically, the extended pad portion 140e of the first pad portion 140 may be located in an area outside the front area of ​​the semiconductor substrate 15 from the position of the auxiliary pad portion 140a along the length direction of the wiring material 125 in each of the plurality of solar cells.

[0233] As an example, the extended pad portion 140e may be formed on the outermost collecting electrode 1131 of the first electrode 1130 that crosses along the length direction of the wiring material 125 on the front surface of each semiconductor substrate 15 of the plurality of solar cells.

[0234] Therefore, the extended pad portion 140e is formed at the first and end of the semiconductor substrate 15 along the length of the wiring member 125, and a plurality of auxiliary pad portions 140a may be formed therebetween. However, the extended pad portion 140e is not necessarily limited to being formed at the first and end of the semiconductor substrate 15 along the length of the wiring member 125, and instead, the extended pad portion 140e may be formed at the first and end of the semiconductor substrate 15 along the length of the wiring member 125 in a plurality of pieces.

[0235] The auxiliary pads 140a are formed at every intersection between the extended pads 140e, or are intermittently arranged in two or four lines as necessary. The number of auxiliary pads 140a is determined according to the required bonding strength and production cost since it is related to the bonding strength of the wiring material 125 and the production cost, but preferably, one is formed for every 1 to 10 lines based on the collecting electrodes 1131, and the number is 6 to 48.

[0236] Further, the width of the extended pad portion 140e may be greater than the line width of the lead 125 and less than 2.5 mm, and the length of the extended pad portion 140e may be greater than the line width of the first electrode 1130 and less than 30 mm.

[0237] As an example, the size of the extended pad portion 140e is 0.25 mm to 2.5 mm in width (in a direction intersecting the length direction of the wiring material) and 0.035 mm to 30 mm in length (in the extension direction of the wiring material), more preferably 0.4 mm to 6 mm. The size of the auxiliary pad portion 140a is 0.035 mm to 30 mm in width, preferably 0.25 mm to 2.5 mm in length.

[0238] More preferably, the width of the extended pad portion 140e may be the same as the width of the auxiliary pad portion 140a, and the length of the extended pad portion 140e may be 3 to 10 times the length of the auxiliary pad portion 140a.

[0239] Therefore, in order for the size of the extended pad portion 140e to be larger than that of the auxiliary pad portion 140a, it is possible to make both the width and the length larger if the length is larger while the length is the same, or to make the width and the length larger while the width is the same, and in this embodiment, when the size is larger, this includes both cases.

[0240] On the other hand, FIG. 41 shows the state of the second electrode when the first electrode is configured to include an expansion pad portion and an auxiliary pad portion in this manner.

[0241] 41, the second electrode 1150 may be configured to include a plurality of collecting electrodes 1151 and a connecting electrode 1153 formed in parallel to each other, similar to the front electrode 1130. Here, the connecting electrode 1153 may be omitted.

[0242] Here, the collecting electrodes 1151 may be formed in a direction intersecting the length direction of the lead 125 .

[0243] The collecting electrode 1151 of the second electrode 1150 may include a plurality of second pad portions (140e', 140a') formed in an area where the lead 125 and the collecting electrode 1151 cross each other.

[0244] Here, the number of the plurality of second pad portions (140e', 140a') is six or more, and may be less than or equal to the number of the collecting electrodes 1151 of the second electrode 115.

[0245] The plurality of second pad portions (140e', 140a') may include an auxiliary pad portion 140a' and an expanded pad portion 140e' having different sizes. Here, the size of the expanded pad portion 140e' may be larger than the size of the auxiliary pad portion 140a'. Therefore, the width or length of the expanded pad portion 140e' may be larger than the width or length of the auxiliary pad portion 140a'.

[0246] In addition, among the second pad portions (140e', 140a'), the extended pad portion 140e' may be located in an area outside the rear area of ​​the semiconductor substrate 15 from the position of the auxiliary pad portion 140a' along the longitudinal direction of the wiring material 125 in each of the plurality of solar cells.

[0247] As an example, among the second pad portions (140e', 140a'), the extended pad portion 140e may be formed on the outermost collecting electrode 1151 of the second electrode 1150 that crosses along the longitudinal direction of the wiring material 125 from the rear surface of each semiconductor substrate 15 of the multiple solar cells.

[0248] Therefore, the extended pad portion 140e' is formed at the first and end of the semiconductor substrate 15 along the length of the wiring member 125, and a plurality of auxiliary pad portions 140a' may be formed therebetween. However, the second pad portion (140e', 140a') is not limited to the extended pad portion 140e' being formed at the first and end of the semiconductor substrate 15 along the length of the wiring member 125 as shown in Fig. 41, and unlike this, the extended pad portion 140e' may be formed at the first and end of the rear region of the semiconductor substrate 15 along the length of the wiring member 125 in a plurality of portions.

[0249] In this manner, when a rear electrode is formed including an extended pad portion 140e' and an auxiliary pad portion 140a', like the front side, at least one of the width, length or number of the plurality of first pad portions (140e, 140a) may be different from at least one of the width, length or number of the plurality of second pad portions (140e', 140a').

[0250] For example, the number of the first pad portions (140e, 140a) formed on the front surface is greater than the number of the second pad portions (140e', 140a') formed on the rear surface. The size of each of the first pad portions 140e, 140a may be smaller than the size of each of the second pad portions 140e', 140a'. In this case, the collecting electrode 1151 formed on the rear surface may also be formed to have a line width larger than that of the collecting electrode 1131 on the front surface.

[0251] Further, the width of the extended pad portion 140e may be greater than the line width of the lead 125 and less than 2.5 mm, and the length of the extended pad portion 140e may be greater than the line width of the first electrode 1130 and less than 30 mm.

[0252] For example, the extended pad portion 140e' and the auxiliary pad portion 140a' of the rear electrode 115 may have a width of 0.25 to 2.5 mm, but may be longer than the first pad portion (140e, 140a) formed on the front surface. For example, the length of the extended pad portion 140e' may be between 0.6 to 12 mm, and preferably about 5.5 to 7.5 mm. The length of the auxiliary pad portion 140a' is between 0.2 and 3 mm, and is between about 0.6 and 1.2 mm. It can be formed with.

[0253] Since the front surface is the surface through which light enters, if the size is increased like the pad portion formed on the rear surface, the shading area caused by the pad portion will become larger and the amount of incident light will decrease. Therefore, the size of the pad portion is reduced, and the number is increased to compensate for the reduced bonding force due to the reduced size.

[0254] The rear extension pad portion and auxiliary pad portion thus configured are preferably equal to or larger than the line width of the wiring material, and equal to or smaller than 5 times the line width.

[0255] Hereinafter, an embodiment in which a solar cell module consisting of solar cells of a conventional structure is provided with a reflector will be described with reference to Fig. 42 to Fig. 45. Fig. 42 is a perspective view showing the overall state of the solar cell module, Fig. 43 is a cross-sectional view taken along line AA in Fig. 42, Fig. 44 is a cross-sectional view taken along line BB in Fig. 42, and Fig. 45 shows the state of the wiring material in the solar cell module shown in Fig. 42.

[0256] 42 to 45, in the solar cell module of this embodiment, multiple solar cells arranged adjacent to each other are connected by multiple thin wiring members 125. The wiring members 125 are electrically connected to a first electrode 113 formed on the front surface of a first solar cell (C1) of two adjacent solar cells, and are also connected to a second electrode 115 formed on the rear surface of a second solar cell C2 adjacent to the first solar cell (C1).

[0257] The solar cell has a thin thickness and a rectangular shape with beveled or rounded corners, with horizontal and vertical dimensions of approximately 156 (mm) x 156 (mm), and a thickness of 150 (μm)-200 (μm).

[0258] A first electrode 113 is located on the front surface, which is the surface where light is incident, and is connected to the wiring material 125 via a first pad portion 140. The first electrode 113 collects charges having a conductivity opposite to that of the semiconductor substrate 111. In one example, if the semiconductor substrate 111 is a p-type semiconductor substrate, the first electrode 113 collects electrons.

[0259] The semiconductor substrate 111 forms a pn junction and is made of an n-type or p-type semiconductor substrate containing a first conductive impurity.

[0260] A second electrode 115 having a similar shape to the first electrode 113 is positioned on the rear surface of the semiconductor substrate 111 and is connected to the wiring material 125 via a second pad portion 160. The second electrode 115 collects charges having the opposite conductivity to that of the first electrode 113.

[0261] The first electrode 1130 and the second electrode 1150 will be described in detail below with reference to different drawings.

[0262] A back surface field portion 154 is located between the second electrode 1150 and the semiconductor substrate 111, and this back surface field portion 154 is formed only locally in a region corresponding to the second electrode 115, where the impurity having the same conductivity as the semiconductor substrate 111 is doped at a higher concentration than the substrate 111.

[0263] The back surface field region 154 has the same conductivity type as the substrate, and if the semiconductor substrate 111 is n-type, the back surface field region 154 is also n-type and can be formed by implanting phosphorus (P) as an impurity into the back surface of the substrate. Preferably, the back surface field region 154 can be locally formed by implanting impurities into the back surface of the substrate using an ion plating method, which is one of the ion implantation methods.

[0264] This rear surface electric field portion 154 forms a potential barrier due to the difference in impurity concentration with the substrate 111, thereby hindering the movement of charges having the same polarity as the substrate on the rear surface side and preventing recombination of different charges on the substrate surface.

[0265] In this embodiment, the back surface field portion 154 is not formed on the entire back surface of the substrate, but is formed only on some of the electrodes. However, it is also possible to form the back surface field portion 154 on the entire back surface of the semiconductor substrate 111.

[0266] In the solar cell having such a configuration, two adjacent solar cells are connected by a wiring member 125 .

[0267] The wiring material 125 has a wire shape as shown in (A) of Figure 45. (B) of Figure 45 shows the cross-sectional shape of the wiring material 125.

[0268] As shown in the figure, the wiring material 125 has a cross-sectional view in which the coating layer 125a coats the core layer 125b with a thin thickness (approximately 12 μm), and the overall thickness is 250 μm-550 μm. It has a thickness of 1 μm.

[0269] The core layer 125b is made of a metal having good conductivity, such as Ni, Cu, Ag, or Al, and the coating layer 125a includes a metal material having a chemical formula, such as Pb, Sn, SnIn, SnBi, SnPb, Sn, SnCuAg, or SnCu, particularly a solder, and can be soldered.

[0270] When connecting two adjacent solar cells, 10 to 15 pieces of wiring material 125 are used if the semiconductor substrate has a size of 156 mm x 156 mm, and are adjusted based on variables such as the size of the substrate, the line width, thickness, and pitch of the electrodes, and the thickness of the wiring material.

[0271] Although the above description is based on the fact that the lead 125 is in the form of a wire having a circular cross section, the cross section may have various shapes such as a rectangle or an oval.

[0272] Such a wiring material 125 connects two adjacent solar cells, one of which is connected to the first electrode 1130 via the first pad portion 140 of the first solar cell C1, and the other of which is connected to the second electrode 1150 via the second pad portion 160 of the second solar cell C2. A preferred method for connecting the electrodes and the wiring material is soldering, which melts and bonds materials, or a conductive adhesive in which conductive particles are included in an adhesive synthetic resin is also possible. do.

[0273] In this embodiment, a first pad section 140 and a second pad section 160 are further positioned at the intersection of the first electrode 1130 and the wiring 125. The first and second pad sections (140, 160) widen the area where the first electrode 1130 and the wiring 125 and the second electrode 1150 and the wiring 125 intersect, thereby reducing the contact resistance when the wiring 125 is connected to the first electrode 1130 and the second electrode 1150, respectively, and increasing the bonding strength between the wiring 125 and the electrodes (1130, 1150).

[0274] In one example of a soldering method, the wiring 125 is placed on the front and rear surfaces of two adjacent solar cells, respectively, so that the wiring 125 faces the first electrode 1130 and the second electrode 1150, and in this state, the coating layer 125a of the wiring 125 is heated to a temperature above its melting point for several seconds. As a result, the coating layer 125a melts and cools, and the wiring 125 is attached to the electrodes.

[0275] In this embodiment, a reflector 170 is further positioned between the solar cells. In the length direction of the wiring material 125, the solar cells are spaced apart from adjacent solar cells by a certain distance, and an inter-section (IA) exists between the solar cells. The reflector 170 is positioned in the inter-section (IA) to scatter light incident on the inter-section (IA) so that the light is incident on the adjacent solar cell.

[0276] Hereinafter, the first electrode 1130 of the solar cell module thus constructed will be described in more detail with reference to FIG.

[0277] In this embodiment, the first electrode 1130 includes a collecting electrode 1131 and a connecting electrode 1133 .

[0278] The collecting electrodes 1131 have a certain width and extend long in one direction, for example, in a direction intersecting the extension direction of the wiring material 125, and are arranged parallel to adjacent ones to form a stripe arrangement. The collecting electrodes 1131 have a width of 35 μm-100 μm, and the pitch (Pf), which is the distance between electrodes, is 1.2 mm-2.2 mm. The numerical ranges presented here are only preferred examples, and the numerical ranges may be adjusted according to various variables.

[0279] The connection electrodes 1133 also have a constant line width and extend long in a direction intersecting with the collecting electrodes 1131 , that is, in the same direction as the extension direction of the wiring material 125 , to electrically connect the collecting electrodes 1131 .

[0280] The connection electrodes 1133 have a line width of 30 μm-120 μm, which is substantially the same as or wider than the collecting electrodes 1131 and smaller than the pad portion, but the pitch (Bdf) is formed between 5 mm-23 mm, which can be larger than the pitch (Pf) of the collecting electrodes 1131 and less than 10 times smaller.

[0281] Alternatively, the connection electrode 1133 may have a line width larger than that of the collecting electrode 1131 and may be equal to or smaller than the lateral width (wfh) of the first pad portion 140 .

[0282] The connecting electrode 1133 in this configuration is not necessarily required, so the first electrode 1130 can also be configured with only the collecting electrode 1131 without the connecting electrode 1133 .

[0283] By omitting the connection electrode 1133, the area onto which light is incident can be increased, and from the manufacturer's point of view, material costs can be reduced, leading to reduced production costs.

[0284] A first pad portion 140 is selectively formed at a point where the collecting electrode 1131 and the connecting electrode 1133 intersect. The vertical width (wfv) of the first pad portion 140 is larger than the line width of the collecting electrode 1131 and smaller than 30 mm, and the horizontal width (wfh) of the first pad portion 140 is larger than the line width of the connecting electrode 1133 and smaller than 2.5 mm, for example, between 0.25 mm and 2.5 mm.

[0285] In a preferred embodiment, the first pad section 140 is preferably formed at every intersection, but may be disposed at equal intervals for each of a plurality of collecting electrodes based on one line of the connection electrode 1133, taking into consideration manufacturing costs, efficiency, etc. In the drawing, the first pad section 140 is disposed at an intersection for every 2*n (n=natural number) lines in the extension direction of the connection electrode 1133. This illustrates the formation of a cross point.

[0286] Therefore, if there are 12 connection electrodes 1131 and 100 collection electrodes 1133, the total number of pads formed on the front surface will be 50*12.

[0287] The collecting electrode 1131, the connecting electrode 1133, and the first pad portion 140 can be simultaneously formed by a screen printing method, in which case they are all made of the same material, for example, silver (Ag). Also, each component can be individually configured as needed.

[0288] Wiring 125 is located directly above connection electrode 1133, and is formed long in a direction parallel to the connection electrode. Therefore, wiring 125 and connection electrode 1133 are arranged to face each other. The line width (Da) of wiring 125 is 250 μm-500 μm, which is smaller than the width (wfh) of first pad portion 140.

[0289] Since the wiring material 125 is soldered while positioned on the connection electrode 1133 in this manner, it is fused and bonded not only to the first pad portion 140 but also to the connection electrode 1133, which reduces the contact resistance between the electrode and the wiring material, increases the efficiency of the solar cell, and may also increase the bonding strength of the wiring material.

[0290] Hereinafter, the second electrode 115 will be described in detail with reference to FIG.

[0291] In this embodiment, like the first electrode 1130, the second electrode 1150 also includes a collecting electrode 1151 and a connecting electrode 1153. In the following description, to avoid confusion with the first electrode 1130, the collecting electrode 1131 and the connecting electrode 1133 of the first electrode 1130 are referred to as the front collecting electrode 1131 and the front connecting electrode 1133, respectively, and the collecting electrode 1151 of the second electrode 1150 is referred to as the rear collecting electrode, and the connecting electrode 1153 is referred to as the rear connecting electrode.

[0292] The rear collector electrodes 1151 have a constant line width and are elongated in one direction, for example, a direction intersecting the extension direction of the wiring material 125, to have a stripe shape, and are arranged parallel to adjacent ones to form a stripe arrangement.

[0293] The rear collecting electrode 1151, like the front collecting electrode 1131, may have a line width of 35 μm-120 μm and a pitch (Pb) of 1.2 mm-2.2 mm. In this case, the line width of the rear collecting electrodes 1151 can be made larger than the line width of the front collecting electrodes 1131 , and the pitch of the rear collecting electrodes 1151 can be made smaller than the pitch of the front collecting electrodes 1131 .

[0294] In this manner, the rear collecting electrode 1151 can be made thicker than the front collecting electrode 1131 .

[0295] In addition, the series resistance of the front is large at about 120-140 (Ω / sq), while the rear is about 2 0-40(Ω / sq) is lower than the front surface. Therefore, the front collecting electrode 113 has a contact surface with the wiring material. To increase the product, a relatively larger number of pad portions is required than on the rear surface, which may result in the pitch of the front collecting electrodes 1131 being larger than that of the rear surface, and therefore the number of rear collecting electrodes 1151 being greater than that of the front collecting electrodes 1131.

[0296] Meanwhile, the figure shows that the line widths of the front collecting electrode 1131 and the back collecting electrode 1151 are the same.

[0297] Rear connection electrode 1153 also has a certain line width and extends long in a direction intersecting rear collecting electrode 1151, i.e., in the same direction as the extension direction of wiring material 125, to electrically connect rear collecting electrode 1151.

[0298] The rear connection electrode 1153 has a line width of 35 μm-120 μm, similar to the rear collecting electrode 1151, and a pitch (Bdb) of 9 mm-13 mm, similar to the front surface.

[0299] Alternatively, the rear connection electrode 1153 may have a line width larger than that of the rear collecting electrode 1151 and may be equal to or smaller than the lateral width (wbh) of the second pad portion 160 .

[0300] This rear connection electrode 1153 is not necessarily required, so the second electrode 115 may also be composed of only the collecting electrode 1151. By omitting the rear connection electrode 1153, the area onto which light is incident may increase, and from the manufacturer's point of view, it may reduce material costs and manufacturing costs.

[0301] A second pad portion 160 is selectively formed at a point where the rear collecting electrode 1151 and the rear connecting electrode 1153 intersect, so that the second electrode 1150 can be connected to the wiring material 125. In this embodiment, the size of the second pad portion 160 is formed to be larger than the first pad portion 140, and for example, the width of the second pad portion 160 may be formed between 0.25 mm and 2.5 mm, and the length of the second pad portion 160 may be formed between 0.1 mm and 12 mm.

[0302] In this embodiment, the number of second pad portions 160 is less than the number of first pad portions 140. In the figure, the number of second pad portions 160 is half that of the first pad portions 140. In the present invention, the first pad portion 140 and the second pad portion 160 are formed to have different sizes and numbers, but although the sizes are the same, the numbers may be different, or the numbers may be the same and only the sizes may be changed in a different way.

[0303] As illustrated in the drawing, the second electrode 1150 is formed such that a locally formed back surface field portion 154 corresponds to the collecting electrode 1151. The back surface field portion 154 is a region doped with impurities at a higher concentration than the semiconductor substrate 111. For example, if the impurity concentration of the semiconductor substrate 111 is 1*1016 (atoms / cm3), the back surface field portion 154 is , and is doped at a high concentration of 2*1020 (atoms / cm3).

[0304] In this embodiment, the rear surface field portion 154 is formed locally only for the collecting electrode 1151, and therefore, like the collecting electrode 1151, the rear surface field portion 154 is also spaced a certain distance from the adjacent one, forming an overall stripe arrangement.

[0305] In this way, the collecting electrode 1151 is formed on the rear surface of the semiconductor substrate 111 with the highly doped rear surface electric field portion 154 as an interface. When measured with a measuring device, the rear series resistance is 20 to 40 (Ω / □), while the front series resistance is about three times larger, 12 0-140(Ω / □).

[0306] This fact refutes the fact that the contact resistance between the wiring 125 and the electrode is much higher on the front side than on the rear side. As a result of the experiment conducted by the present inventor, it was found that the efficiency of the solar cell is not affected even if the number of the second pad parts 160 is reduced to 1 / 2 of the first pad parts 140. However, the number of the second pad parts 160 is less than half that of the first pad parts 140. It was shown that as the temperature increases, the efficiency of the solar cell drops sharply.

[0307] In this embodiment, the number of second pad units 160 is configured to be less than the number of first pad units 140, so that the efficiency of the solar cell can be maintained while effectively reducing the manufacturing cost.

[0308] The rear collecting electrode 1151, the rear connecting electrode 1153, and the second pad portion 160 can be simultaneously formed by a screen printing method, in which case they are all made of the same material, for example, silver (Ag). Also, each component can be individually constructed as necessary.

[0309] The wiring members 125 are located directly above the rear connection electrodes 1153 and are formed long in a direction parallel to the rear connection electrodes 1153. The pitch of the wiring members is substantially the same as the pitch (Bdb) of the connection electrodes 1153.

[0310] Even on the rear side, the wiring material 125 is soldered while being positioned on the rear connection electrode 1153 in this manner, so that even if the number of second pad portions 160 is relatively smaller than the number of first pad portions 140, the wiring material 125 is fused and bonded not only to the second pad portions 160 but also to the rear connection electrode 1153 in its length direction, thereby reducing the contact resistance between the electrode and the wiring material while also increasing the adhesive strength of the wiring material.

[0311] As described above, in this embodiment, the second pad portions 160 are formed in smaller numbers than the first pad portions 140, so that the positions of the first pad portions 140 and the second pad portions 160 are arranged in various arrangements according to the positions of the first electrodes and the second electrodes. In this regard, please refer to Figures 48 to 51.

[0312] In this drawing, only the components necessary for explanation are shown in a simplified manner, with a dashed line indicating front collecting electrode 1131, a dotted line indicating rear collecting electrode 1151, and a two-dot dashed line indicating wiring 125. It is also assumed that wiring 125 is located on the same line on the front and rear surfaces, and that first pad portion 140 and second pad portion 160 have the same size.

[0313] First, FIG. 48 shows a case where the pitches of front collecting electrode 1131 and rear collecting electrode 1151 are the same, and front collecting electrode 1131 and rear collecting electrode 1151 are positioned on the same line.

[0314] The first pad sections 140 are formed at multiples of 2, and there is one intersection where there is no first pad section 140 in the extension direction of the wiring material 125. The second pad sections 160 are formed at multiples of 4, and there are three intersections between which there are no second pad sections 160. As a result, the pitch (Pdf), which is the distance between the first pad sections 140, is smaller than the pitch (Pdb) of the second pad sections 160.

[0315] Meanwhile, the second pad portions 160 are formed in multiples of four, while the first pad portions 140 are formed in multiples of two. Therefore, when the first pad portions 140 and the second pad portions 160 are overlapped, all the second pad portions 160 are positioned so as to overlap with the first pad portions, and one first pad portion 140 is positioned between the second pad portions 160.

[0316] In comparison, Fig. 49 shows a state in which the front collecting electrode 1131 and the rear collecting electrode 1151 are positioned on the same line as in Fig. 48, but the second pad portions 160 do not overlap the first pad portions 140 but are formed between the first pad portions 140. In this case, the first pad portions 140 are formed in multiples of 2, and the second pad portions 160 are formed in multiples of 4, so that none of the second pad portions 160 overlap the first pad portions 140.

[0317] FIG. 50 illustrates a case where the pitch of the front collecting electrodes 1131 and the rear collecting electrodes 1151 are the same, but the front collecting electrodes 1131 and the rear collecting electrodes 1151 are not collinear.

[0318] In this case, the front collecting electrodes 1131 and the rear collecting electrodes 1151 are arranged alternately and not on the same line in the extension direction of the wiring 125. Also, the first pad section 140 is formed in a multiple of 2, and the second pad section 160 is formed in a multiple of 4, so that the first pad section 140 and the second pad section 160 are not overlapped.

[0319] 51 shows the case where the pitch of the front collecting electrodes 1131 is larger than the pitch of the rear collecting electrodes 1151. In this case, since the pitch of the rear collecting electrodes 1151 is smaller than the pitch of the front collecting electrodes 1131, the front collecting electrodes 1131 and the rear collecting electrodes 1151 may have various configurations such as being collinear, adjacent, or far apart.

[0320] Therefore, the second pad section 160 may be located at a position overlapping the first pad section 140, may be located at a position only partially overlapping the first pad section 140, or may be located at a different position.

[0321] 52 to 58, the reflector 170 of the solar cell module shown in Fig. 42 will be described below. Fig. 52 is a diagram for explaining the reflector, and is a plan view focusing on the inter section (IA), and Fig. 53 is a cross-sectional view taken along line CC in Fig. 52.

[0322] The second solar cell C2 is separated from the first solar cell C1 by an inter-section (IA) and is connected to the wiring member 125. A reflector 170 is located in the inter-section (IA).

[0323] In this embodiment, the reflector 170 is a bar-shaped rectangular parallelepiped, and has good reflection. As an example, the reflector 170 is made of the same material as the electrodes (113, 115) or the wiring material 125.

[0324] Reflector 170 is fixed to wiring 125, and is preferably soldered to wiring 125. In this case, when wiring 125 is soldered to electrodes (113, 115), reflector 170 is also soldered, so that the number of work steps can be reduced, and manufacturing costs can be reduced.

[0325] Preferably, the reflector 170 is connected to all of the wiring members 170 connecting the two solar cells. In this embodiment, twelve wiring members 125 are used to electrically connect the two solar cells (c1, c2), and the reflector 170 is soldered to all of the twelve wiring members.

[0326] Meanwhile, one end of the wiring 125 is connected to the first electrode 1130 of the first solar cell (C1), and the other end is connected to the second electrode 1150 of the second solar cell C2. Therefore, the wiring 125 is inclined at a predetermined angle in the inter section (IA), and the reflector 170 fixed to the wiring 125 in the inter section (IA) is also inclined at a predetermined angle.

[0327] Therefore, when light is incident on the inter section (IA), the light is reflected by the reflector 170. The light is reflected from the surface of the solar cell C1 and enters the adjacent second solar cell C2.

[0328] FIG. 54 shows a state in which a reflector 170 is positioned further inward than the edge of the first solar cell and is coupled to the wiring material.

[0329] In FIG. 54, the reflector 170 is further formed a certain distance (t) inward from the edge of the first solar cell (C1) and attached to the wiring material 125.

[0330] Meanwhile, one end of the wiring material 125 is connected to the first electrode 1130 of the first solar cell (C1), and the other end is connected to the second electrode 1150 of the second solar cell C2. Therefore, the wiring material 125 bends from top to bottom at the tip of the first solar cell (C1), and when the wiring material 125 made of a metal film bends in this manner, it is likely to break at the point of bending.

[0331] In this embodiment, reflector 170 is placed against the bent portion of wiring 125, so that the problem of wiring 125 being broken can be prevented.

[0332] FIG. 55 shows a state in which reflectors 170 are formed on the front and rear surfaces of the wiring material 125 in the inter-section (IA).

[0333] 55, the same as described above, except that reflectors 170 are formed above and below wiring 125, sandwiching the wiring 125. As such, reflector 170 is also formed below the wiring, so that it is possible to prevent the wiring 125 from being broken in the inter section (IA), and further, reflector 170 made of a metal material is further formed in the inter section (IA), so that the line resistance of wiring 125 can be reduced.

[0334] 56 shows how the surface of the reflector is uneven. The surface of the reflector 170 includes the unevenness 171, and when light is reflected on the surface of the reflector 170, it causes diffuse reflection, which can effectively increase the amount of light incident on the solar cell.

[0335] Fig. 57 shows that the surface of the reflector is composed of an inclined surface (Cs) and that unevenness 171 is formed on the inclined surface. Fig. 56 shows an example in which the inclined surface (Cs) is rounded, but any shape may be used as long as the height changes depending on the position. If the surface of the reflector has an inclined surface (Cs) in this way, light is further refracted from the surface of the reflector toward the solar cell by an amount corresponding to the inclination angle, so that the amount of light incident on the solar cell can be effectively increased.

[0336] The above description of the reflectors has been given taking as an example a case where one reflector 170 is arranged in the inter section (IA), but at least two or more reflectors 170 may be arranged as shown in Fig. 58. In this case, the multiple reflectors 170 may all be arranged as described in Figs. 53 to 57, or each of the reflectors may be configured in a different manner from each other. As an example, when there are two reflectors 170 in the inter section (IA), one is configured as shown in Fig. 55, and the other is configured as shown in Fig. 57.

[0337] In addition, in FIG. 58, an example is described in which the reflector 170 is divided into multiple parts in the extension direction of the wiring material, but it may also be configured to be divided into multiple parts in a direction intersecting the wiring material.

Claims

[Claim 1] A plurality of solar cells, each of which includes a semiconductor substrate, a first electrode formed on a front surface of the semiconductor substrate, and a second electrode formed on a rear surface of the semiconductor substrate; a plurality of wiring members connecting a first electrode formed on a first solar cell to a second electrode formed on a second solar cell, the first electrode being adjacent to the second solar cell among the plurality of solar cells; The first electrode includes a plurality of first collector electrodes formed in parallel to each other; a plurality of first connection electrodes that are continuously formed in a direction intersecting the plurality of first collecting electrodes and connect the plurality of first collecting electrodes; and in a region that overlaps the first connection electrodes, a plurality of first pad portions each having a width greater than a line width of the first connection electrode; The plurality of first pad portions include a first auxiliary pad portion having a first area and a first extended pad portion having a second area larger than the first area, The width of the first auxiliary pad portion is smaller than the width of the first extended pad portion, the first extension pad portion is located in an outermost region of the semiconductor substrate along a longitudinal direction of the wiring member in each of the plurality of solar cells and is located outside any of the first auxiliary pad portions; a width of the wiring member is smaller than a width of the first pad portion and is larger than a width of the first connection electrode; the wiring members are positioned to overlap the first connection electrodes and are provided on the first pad portion to be connected to the first extended pad portion and the first auxiliary pad portion; A solar cell module, wherein a pitch of the first pad portions is larger than a pitch of the first collecting electrodes and is larger than a length of the first auxiliary pad portions.

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