solar cell module

Abstract

To provide a solar cell module in which a plurality of solar cells are connected to each other with a plurality of wiring materials.SOLUTION: A solar cell module of the present invention includes a semiconductor substrate, a plurality of solar cells including a first electrode and a second electrode that are formed alternately in a first direction in parallel to a back surface of the semiconductor substrate, a plurality of first wiring materials formed in a second direction intersecting with the first direction in order to connect the solar cells in series, electrically connected to the first electrode by a conductive layer, and insulating the second electrode, and a second wiring material connecting the solar cells in series, formed in the second direction, electrically connected to the second electrode by the conductive layer, and insulating the first electrode. Each of the solar cells includes a first pad part formed in a region where the first wiring material intersects with the first electrode, and a second pad part formed in a region where the second wiring material intersects with the second electrode. The first pad part or the second pad part includes a first contact pad part that is wider than each of the first and second electrodes and includes at least one or more of second contact pad parts 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 connected to each other by a plurality of wiring members. [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 these, 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. It 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 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 generated 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, which 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 alternately and parallel to each other in a first direction on a rear surface of the semiconductor substrate, a plurality of first wiring members formed in a second direction intersecting the first direction to connect the plurality of solar cells in series, the first wiring members being electrically connected to the first electrodes by a conductive layer and insulated from the second electrodes, and a second wiring member formed in the second direction to connect the plurality of solar cells in series, the second wiring member being electrically connected to the second electrodes by a conductive layer and insulated from the first electrodes, each of the plurality of solar cells including 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, the first pad portion or the second pad portion having a first contact pad portion having a width greater than the width of each of the first and second electrodes, and 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 disconnected 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] The first and second pad portions may be formed of the same material as the first electrode or the second electrode, and at least one of the first and second pad portions 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] Each of the plurality of solar cells may include a plurality of 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 or second electrode, or may be made of the same material as the insulating layer or conductive layer.

[0016] Another example of the solar cell module of the present invention includes a semiconductor substrate, a plurality of solar cells including first electrodes formed parallel to each other on the front surface of the semiconductor substrate and second electrodes formed on the rear surface of the substrate, and a plurality of wiring members connecting the plurality of first electrodes formed on adjacent first solar cells among the plurality of solar cells to a plurality of second electrodes formed on adjacent second solar cells, wherein 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 from 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. For 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 portions, the expansion pad portions and the auxiliary pad portions may be repeatedly arranged in a predetermined 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 pad portions may be six or more and may be less than or equal to the number of the first electrodes, and the number of the second pad portions may be six or more and may be less than or equal to the number of the second electrodes. For example, the number of the first pad portions may be greater than the number of the second pad portions.

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

[0025] Here, the line width of the plurality of 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] 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 may be less 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, so that 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. [Effects of the Invention]

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

[0033] The drawings attached to this specification are diagrammatic in order to easily explain the invention, and therefore the attached drawings may differ from the actual state. [Figure 1] 1 is a diagram showing an overall view of a solar cell module according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram showing a schematic cross-sectional view of the solar cell shown in FIG. [Figure 3] FIG. 2 is a diagram showing the overall appearance of the wiring material in the solar cell module of FIG. [Figure 4] FIG. 2 is a diagram showing a cross section of a wiring material in the solar cell module of FIG. [Figure 5] 10A and 10B are diagrams showing the state of a wiring material according to another embodiment; [Figure 6] FIG. 2 is a diagram showing a cross section of a wiring material. [Figure 7] 10A and 10B are diagrams illustrating buffer portions formed on wiring materials. [Figure 8] FIG. 2 is a simplified diagram showing the electrodes and wiring materials of each solar cell in the solar cell module shown in FIG. 1, and the connections between them. [Figure 9] FIG. 9 is a diagram showing a cross section taken along line II' in FIG. 8. [Figure 10] 9 is a diagram showing a cross section taken along line II-II' in FIG. 8. FIG. [Figure 11] FIG. 10 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] FIG. 12 is a diagram showing a cross section taken along line III-III' in FIG. [Figure 13] FIG. 10 is a cross-sectional view showing a pad portion made of a layer different from the electrode. [Figure 14] FIG. 10 is a diagram showing a state in which the pad portion is configured to further include a slit. [Figure 15] FIG. 10 is a diagram showing a configuration in which the size of the pad portion varies depending on the position. [Figure 16] FIG. 10 is a diagram showing a configuration in which the size of the pad portion varies depending on the position. [Figure 17] FIG. 10 is a diagram showing an electrode structure including a broken portion. [Figure 18] 10A and 10B are diagrams illustrating how the width of a broken portion varies depending on the position. [Figure 19] FIG. 10 is a diagram showing the state of a broken portion including a bank. [Figure 20] FIG. 20 is a diagram showing a cross section taken along line IV-IV′ in FIG. 19. [Figure 21]10A and 10B are diagrams showing connection electrode portions that electrically connect pad portions; [Figure 22] FIG. 22 is a diagram showing a cross section taken along line VV' in FIG. 21. [Figure 23] 1 is a diagram showing a flow of a manufacturing method of a solar cell module according to an embodiment. [Figure 24] FIG. 10 is a diagram showing a state in which a dispersion layer is disposed between a conductive layer and an insulating layer. [Figure 25] FIG. 25 is a diagram showing a cross section taken along line VI-VI' in FIG. 24. [Figure 26] FIG. 10 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 section taken along line VII-VII′ in FIG. 26. [Figure 28] FIG. 10 is a diagram showing a state in which a plurality of dispersion layers are formed. [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. [Figure 30] FIG. 30 is a diagram showing a cross section taken along line XI-XI' in FIG. 29. [Figure 31] 30 is a diagram showing a cross section taken along line XII-XII' in FIG. 29. FIG. [Figure 32] FIG. 10 is a diagram showing the state of the wiring material. [Figure 33] FIG. 2 is a diagram showing the state of a first electrode according to the first embodiment. [Figure 34] FIG. 10 is a diagram showing the state of a first electrode according to the second embodiment. [Figure 35] FIG. 10 is a diagram showing the state of a first electrode according to a third embodiment. [Figure 36] FIG. 10 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 according to the fifth embodiment. [Figure 38] FIG. 13 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. [Figure 40]FIG. 10 is a diagram showing a state in which the first electrode includes an expansion pad portion and an auxiliary pad portion. [Figure 41] FIG. 10 is a diagram showing a state in which the second electrode includes an expansion pad portion and an auxiliary pad portion. [Figure 42] FIG. 1 is a diagram showing the overall configuration of a solar cell module including a reflector, which is made up of solar cells of a conventional structure. [Figure 43] FIG. 43 is a diagram showing a cross section taken along the line AA in FIG. 42. [Figure 44] FIG. 43 is a diagram showing a cross section taken along the line BB in FIG. 42. [Figure 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] 10A and 10B are diagrams showing the positional relationship between the front pad portion and the rear pad portion. [Figure 49] 10A and 10B are diagrams showing the positional relationship between the front pad portion and the rear pad portion. [Figure 50] 10A and 10B are diagrams showing the positional relationship between the front pad portion and the rear pad portion. [Figure 51] 10A and 10B are diagrams showing the positional relationship between the front pad portion and the rear pad portion. [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 state cut 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 INVENTION

[0034] 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 below through the embodiment also belongs to the present invention, since each component has already been described.

[0035] FIG. 1 is a diagram showing the overall appearance of a solar cell module according to one embodiment of the present invention, illustrating an example in which three solar cells are connected to each other adjacent to each other in the horizontal direction.

[0036] Each of the solar cells (10a-10c) has a cubic shape with a small thickness, and a first conductivity type electrode (hereinafter referred to as the first electrode) 11 and a second conductivity type electrode (hereinafter referred to as the second electrode) 13 that separate and collect electrons and holes are formed on the rear surface.

[0037] The first electrodes 11 and the second electrodes 13 may be formed in a first direction on the rear surface of the semiconductor substrate 15 so as to be alternately parallel to each other. For example, as shown in FIG. 1, the first electrodes 11 and the second electrodes 13 are arranged in a first direction so as to be elongated in the vertical direction and parallel to adjacent electrodes. Also, the first electrodes 11 and the second electrodes 13 are arranged in a second direction so as to be alternately spaced apart from adjacent electrodes.

[0038] The first electrode 11 and the second electrode 13 are electrically connected to wiring members 25. 1 and is connected to the second electrode 13 or the first electrode 11 of another adjacent solar cell.

[0039] 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), to electrically connect two adjacent solar cells to each other in order to connect the solar cells (10a, 10b, 10c) in series. The solar cells (10a-10c) may be connected in series or in parallel, but the following description will exemplify the solar cells (10a-10c) being connected in series.

[0040] The wiring member 25 includes a first wiring member 21 and a second wiring member 23. Taking the second solar cell 10b disposed in the center as an example, the first wiring member 21 can be electrically connected to the first electrode 11 and insulated from the second electrode 13, and the second wiring member 23 can be electrically connected to the second electrode 13 and insulated from the first electrode 11.

[0041] Therefore, first wiring member 21 is electrically connected to first electrode 11 of second solar cell 10b located in the center, and the other end is connected to second electrode 13 of third solar cell 10c, connecting second solar cell 10b and third solar cell 10c. Second wiring member 23 is electrically connected to second electrode 13 of second solar cell 10b located in the center, and the other end is connected to first electrode 11 of first solar cell 10a, connecting second solar cell 10b and first solar cell 10a.

[0042] The first wiring members 21 and second wiring members 23 are arranged alternately in the vertical direction, and are arranged so that adjacent ones are parallel to each other.

[0043] In this way, by arranging the wiring member 25 in a direction that intersects with the electrodes (11, 13), it becomes easier to connect the wiring member 25 to the electrodes (11, 13) and also to align the electrodes (11, 13) with the wiring member 25. In this embodiment, the first electrodes 11 and the second electrodes 13 are all arranged parallel to the rear surface, and the wiring member 25 is connected in a direction that intersects with this, so that the thermal deformation direction of the wiring member 25 intersects with the thermal deformation direction of the electrodes (11, 13), thereby protecting the solar cell from potential stress caused by thermal deformation.

[0044] 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).

[0045] 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.

[0046] Between the first electrode 11 and the semiconductor substrate 15, and between the second electrode 13 and the semiconductor substrate 15, an emitter 18 that lowers the potential barrier and a back surface field region 19 are formed with a thin thickness, so that charges can be easily collected in the direction of the electrodes (11, 13).

[0047] 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 susceptible to thermal deformation, and in particular, because the first and second electrodes (11, 13) have different thermal expansion coefficients from the semiconductor substrate 15, potential stress due to thermal deformation is inherent, which can lead to physical damage or bending of the solar cell.

[0048] In this embodiment, the electrode width (wd) is increased compared to the conventional method, but the thickness (td) is relatively reduced to solve the problem of thermal deformation. Experiments have shown that when 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, stable charge collection is possible and the above-mentioned problem is solved.

[0049] Figure 3 shows the overall appearance of the wiring material in the solar cell module of Figure 1, and Figure 4 shows its cross-section. As shown in Figures 3 and 4, wiring material 25 is a thin, rectangular strip. The cross-section of wiring material 25 is rectangular, with a width (sd) of 1.0-50 mm and a thickness (Ad) of 25-200 μm.

[0050] When the wiring member 25 is connected to the electrodes 11 and 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 member 25 is configured to have a reduced thickness to minimize thermal deformation, while having a wider width (sd) to improve charge transport.

[0051] The wiring material 25 has a cross-sectional appearance in which a coating layer 251 forming the surface coats a core layer 253 to 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 thereof.

[0052] 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 with a circular cross-section. Wiring member 35 according to this embodiment also includes coating layer 351 and core layer 353 and has a diameter of between 250 μm and 500 μm. As such, in this embodiment, because wiring member 25 has a circular cross-sectional shape, the problem of thermal deformation caused by wiring member 35 can be reduced compared to the wiring member shown in FIG. 3.

[0053] 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 polygonal or have a curved surface.

[0054] The wiring member 25 configured in this manner may further include a buffer portion 25a. Figure 7 illustrates an example in which the buffer portion is formed on the strip-shaped wiring member as in Figure 3 .

[0055] The buffer portion 25a is configured to allow the wiring material to stretch 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, where the actual length of the wiring material belonging to the buffer portion 25a is longer than the width (Bwd) of the buffer portion 25a. Figure 7 shows an example in which the buffer portion 25a is wrinkled and the length of the wiring material belonging to the buffer portion 25a is longer than the width (Bwd) of the buffer portion 25a.

[0056] 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, multiple solar cells are connected to each other by wiring 25 while maintaining a constant spacing (fd). Since the buffer portion 25a is located between the solar cells, even if the spacing between the solar cells connected by the wiring 25 increases, the buffer portion 25a may increase accordingly. Ultimately, this protects the solar cell module from physical shocks, such as breakage of the wiring 25 due to stress applied to the wiring 25 or separation of the connection between the wiring 25 and the electrodes (11, 13). Therefore, the width (Bwd) of the buffer portion 25a should be equal to or smaller than the spacing (fd) between the solar cells.

[0057] Hereinafter, the relationship in which the electrodes of each solar cell and the wiring material are electrically connected in the solar cell module configured as above will be described with reference to FIGS.

[0058] Figure 8 is a simplified diagram showing the electrodes and wiring materials of each solar cell in the solar cell module shown in Figure 1, as well as the connection relationships between them. Figure 9 is a diagram showing a cross section taken along line I-I' in Figure 8, and Figure 10 is a diagram showing a cross section taken along line II-II' in Figure 8.

[0059] Referring to this drawing, in each solar cell (10a-10c), the first electrodes 11 and second electrodes 13 extend parallel to adjacent ones, and the first electrodes 11 and second electrodes 13 are arranged alternately in the vertical direction (the y-axis direction of the drawing).

[0060] 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 (x-axis direction in the drawing).

[0061] 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 alternately. Meanwhile, the first electrodes 11 and second electrodes 13 collect charges of the first conductivity and the second conductivity, which are opposite to each other, and the first wiring members 21 and second wiring members 23 also transfer 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 the charge can be collected and transferred in a balanced manner throughout each solar cell.

[0062] 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 the first solar cell 10a and the second solar cell 10b to electrically connect them together.

[0063] 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 prevent electrical connection between the wiring member and the electrode.

[0064] The conductive layer 41 is made of epoxy-based or silicone-based synthetic resin containing conductive particles, providing 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, such as a tin alloy having a chemical formula such as SnIn, SnBi, SnPb, Sn, SnCuAg, or SnCu.

[0065] 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), and when heated above its melting temperature, the solder particles in the solder paste melt and melt-bond the two base materials.

[0066] Conductive layer 41 is configured in this manner, and electrically connects first wiring member 21 / second wiring member 23 and first electrode 11 / second electrode 13.

[0067] The insulating layer 43 is formed of an adhesive insulating material such as an epoxy-based or silicone-based synthetic resin, or a ceramic, and prevents electrical connection between the first wiring material 21 and the first electrode 11 / second electrode 13.

[0068] 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, electrically connecting them.

[0069] In addition, 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, preventing electrical connection between them.

[0070] 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.

[0071] On the other hand, in the third solar cell 10c, the conductive layer 41 is located in a fifth region (A5) where the first wiring member 21 and the second electrode 13 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. Therefore, 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.

[0072] 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).

[0073] 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. Therefore, second wiring member 23 is electrically connected only to first electrode 11 from first solar cell 10a and is insulated from second electrode 13.

[0074] As a result, the second wiring member 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 Figure 10).

[0075] 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. 20 pieces of the first wiring members 21 and 20 pieces of the second wiring members 23 are required, but this can be adjusted appropriately depending on the size of the solar cell, the size of the electrodes, the size of the wiring members, etc.

[0076] Furthermore, since the first wiring member 21 and the second wiring member 23 each connect two adjacent solar cells, for example, the first and third solar cells (10a, 10c), to 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.

[0077] Figure 11 shows pad portion 14 formed where electrodes (11, 13) and wiring material 25 intersect, 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.

[0078] As described above, conductive layer 41 is located at the connection points where electrodes (11, 13) and wiring member 25 are electrically connected, electrically connecting first wiring member 21 and first electrode 11, and second wiring member 23 and second electrode 13.

[0079] At the non-connection points where the electrodes (11, 13) and the wiring member 25 are not electrically connected, an insulating layer 43 is located to insulate the first wiring member 21 from the second electrode 13, and the second wiring member 23 from the first electrode 11.

[0080] Pad portion 14 is formed at each connection point of the plurality of solar cells, and includes first pad portion 141 and second pad portion 143. Here, first pad portion 141 can be formed in a partial region of first electrode 11 that is electrically connected to first wiring member 21 within the region where first electrode 11 intersects with first wiring member 21, and can be formed in a partial region of second electrode 13 that is electrically connected to second wiring member 23 within the region where second electrode 13 intersects with second wiring member 23.

[0081] 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, and also reduces charge loss by increasing the intersection area between the electrodes (11, 13) and the wiring material 25 and reducing surface resistance when the charges collected by the electrodes (11, 13) are transferred to the wiring material 25.

[0082] In this embodiment, the pad portion 14 is described as being formed of the same material as the electrodes (11, 13) and configured as a part of the electrodes (11, 13), but is not limited to this. For example, the pad portion 14 may be formed of a different conductive material from the electrodes (11, 13), as illustrated in Figure 13, or the conductive layer 41 may be configured as the pad portion 14.

[0083] The pad portion 14 has a horizontal width (Pwa) that is smaller than the distance (Gwa) between the first electrode 11 and the second electrode 13, but larger than the line width (Gw) of the first and second electrodes (11, 13). The vertical width (Pwb) can be smaller than the distance (Wb) between the first wiring member 21 and the second wiring member 23, but larger than the line width (Bw) of the wiring member 25.

[0084] If the width (Pwa) of the pad portion 14 is larger than the distance (Gwa) between the first electrode 11 and the second electrode 13, the pad portion 14 may cause adjacent electrodes to come into contact with each other, resulting in a short circuit between them. Therefore, the pad portion 14 must be larger than the line width (Gw) of the electrodes. Furthermore, if the length (Pwb) of the pad portion 14 is larger than the distance (Wb) between the first wiring member 21 and the second wiring member 23, the pad portion may come into contact with the pad formed on the adjacent electrode, resulting in a short circuit between the two adjacent electrodes. However, the width (Pwb) of the pad portion 14 must be smaller than the line width (Bw) of the wiring member 25 to ensure a stable connection between the wiring member and the electrode.

[0085] FIG. 13 shows a cross section 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.

[0086] The pad portion 14' of this embodiment can be printed by a conventional screen printing method, an ink jet method, or the like. The pad portion 14' can be formed by a method such as a dispensing method and has a thickness of 1 μm to 20 μm. The pad portion 14' can be made of 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' can be made of the same material as the conductive layer 41.

[0087] In this embodiment, the pad portion 14' configured in this manner 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.

[0088] In other words, if the pad portion 14' is not present or is configured as part of the electrode, the material constituting the conductive layer 41 or insulating layer 43 can only 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.

[0089] In contrast, when the pad portion 14' is composed of an electrode and other layers as in this embodiment, the material for the conductive layer 41 or the insulating layer 43 can be selected based on the pad portion 14'. However, unlike the electrode, the pad portion 14' is not formed on a substrate, so the material for the pad portion 14' can be changed as needed, thereby broadening the range of materials for the conductive layer 41 or the insulating layer 43.

[0090] For example, if the electrodes (11, 13) are made of Niv and 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, or Au, solder made of tin or a tin alloy can be used as the conductive layer material.

[0091] Figure 14 shows a configuration in which the pad portion further includes a slit. As shown in Figure 14, at least one of the first and second pad portions 14 may include a slit 145 formed as a narrow groove. The slits 145 are formed in the length direction of the wiring material 25, and multiple slits 145 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 (Figure 14 (A)).

[0092] 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 with a certain pattern. It is also possible to form it without turns.

[0093] 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 increases, 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.

[0094] 15 and 16 show a configuration in which the size of the pad portion 14 varies depending on the position. FIG. 16 illustrates an example in which only one pad portion per line is selectively enlarged, while FIG. 17 illustrates an example in which only one pad portion per line is selectively enlarged.

[0095] 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 greater than the widths of the first and second electrodes (11, 13), and at least one second contact pad 14b having a size greater 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. Figure 15 shows a plan view of an electrode, illustrating 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.

[0096] 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 width) (Pcb) of the second contact pad portion 14b larger than those of the first contact pad portion 14a. Figure 15 shows that the width and length of the second contact pad portion 14b are both larger than those of the first contact pad portion 14a.

[0097] On the other hand, in order to connect the electrodes (11, 13) to the pad portion 14, the entire solar cell must be exposed to high heat, which can cause the solar cell to bend during the connection process. However, in this embodiment, by configuring the second contact pad portion 14b to be larger than the first contact pad portion 14a and attaching the wiring material 25 to the second contact pad portion 14b first, and then attaching the wiring material 25 to the first contact pad portion 14a at a later time, the solar cell is exposed to high temperatures at different times, thereby reducing the problem of substrate bending. In addition, the contact resistance between the wiring material 25 and the physical adhesive force of the first and second electrodes (11, 13) can be further improved through the use of the second contact pad portion 14b.

[0098] During the manufacturing process, the wiring material 25 is fixed by heat treatment while it is placed on a liquid conductive layer. However, because the conductive layer is liquid, the wiring material 25 may warp during the heat treatment. However, this problem can be solved by first fixing the wiring material only to the second contact pad portion 14b, and then fixing it to the first contact pad portion 14a by heat treatment.

[0099] In this embodiment, the wiring material is heated to a temperature before the conductive layer and insulating layer are hardened, and temporarily fixed to the second contact pads 14b. Thereafter, 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 pads 14b required for temporary fixing be smaller than the number of first contact pads 14a.

[0100] FIG. 17 shows the state of the electrodes (11, 13) which further include a broken portion 111.

[0101] As shown in Figure 17, the solar cell module of the present invention can include a broken portion 111 in which the electrode (11, 13) is partially disconnected, in at least a portion of the second electrode 13 insulated from the first wiring member 21 or in at least a portion of the first electrode 11 insulated from the second wiring member 23.

[0102] In this embodiment, the disconnection portion 111 is a portion where the electrode (11, 13) is broken, and the electrode (11, 13) is missing for a certain width (Cw) in the longitudinal direction of the electrode (11, 13).

[0103] The 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.

[0104] The disconnection portion 111 essentially cuts off electrical connection between the electrodes (11, 13) and the wiring member 25 by preventing physical contact between them at the disconnection point. The width (Cw) of such a disconnection portion must be at least larger than the line width (Bw) of the wiring member 25.

[0105] 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.

[0106] 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, so there is no need to place an insulating layer 43 at each non-connected point, which increases work yield while correspondingly reducing manufacturing costs.

[0107] Figure 17 shows an example in which open sections 111 exist in all of the second electrode 13 insulated from the first wiring member 21 and the first electrode 11 insulated from the second wiring member 23. However, such open sections 111 may exist only in a portion of the second electrode 13 insulated from the first wiring member 21 and in a portion of the first electrode 11 insulated from the second wiring member 23. Alternatively, an insulating layer 43 may exist in the remaining portion, and the insulating layer 43 may insulate the first wiring member 21 from the second electrode 13 and insulate the second wiring member 23 from the first electrode 11.

[0108] FIG. 18 is a diagram showing how the width of the broken portion varies depending on the position.

[0109] 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 electrodes (11, 13) belonging to the third group (G3) are arranged in the center of the solar cell between the first group (G1) and the second group (G2).

[0110] In this embodiment, the broken wire portion 111 includes a first long broken wire portion 113 formed on the electrodes (11, 13) belonging to the first group (G1), a second long broken wire portion 115 of the second group (G2), and a short broken wire portion 117 of the third group (G3).

[0111] First, the first long broken portion 113 is separated by a first distance (Da1) in the longitudinal direction of the electrodes, the second long broken portion 115 is separated by a second distance (Da2), and the short broken portion 117 is separated by a third distance (Da3). Comparing the first distance (Da1) and the second distance (Da2), it is desirable that they are the same, but they should be at least greater than the third distance (Da3). Furthermore, the third distance (Da3) is at least greater than the line width of the wiring member 25, and the first distance (Da1) and the second distance (Da2) are smaller than the distance between the first wiring member 21 and the second wiring member 23.

[0112] In this way, since the disconnection portion 111 includes the first long disconnection portion 113, the second long disconnection portion 115, and the short disconnection portion 117, which are spaced apart depending on their positions, when the wiring material 25 is fixed to the solar cell (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 electrode at the non-connection point, thereby preventing a short circuit.

[0113] FIG. 19 is a diagram showing the state of a broken portion including a bank, and FIG. 20 is a diagram showing the state of a cross section cut along line IV-IV' in FIG. 19. In this embodiment, bank 51 refers to an insulating material that selectively encloses 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 island shapes based on wiring material 25. First bank 51a is arranged on top based on wiring material 25, and second bank 51b is arranged on the bottom.

[0114] The paired banks 51 are located at the ends of the electrodes forming the disconnection portion 111 and have a cross-sectional shape 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 other reasons.

[0115] 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. The vertical width (Bvw) should be smaller than the distance (Wb) between the wiring materials. do.

[0116] If the 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, preventing physical contact between the wiring material 25 and the electrodes (11, 13). If the 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 disconnection portion 111 in the vertical direction, preventing physical contact between the pad portion 14 and the wiring material 25 at the connection point.

[0117] The bank 51 thus configured can be made of the same material as the insulating layer 43 or can be made of a different material. Although the planar shape of the bank 51 is shown as a rectangle, there is no restriction on the shape, such as a circle or an ellipse.

[0118] FIG. 21 is a diagram showing a connection electrode portion for electrically connecting the pad portion 14, and FIG. 22 is a diagram showing a cross section taken along line VV' in FIG.

[0119] 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.

[0120] 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 the wiring material 25. This connection electrode 61 can be formed in the same process as the electrodes (11, 13), or it can be separate 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. If the connection electrode 61 is formed in a different process, the connection electrode and the electrodes can be made of different materials, increasing the range of materials to choose from for forming the connection electrode.

[0121] If the connection electrode portion 61 is formed like the electrodes (11, 13), it is made of the same material as the electrodes (11, 13), and if it is formed in a different process, it can be made of a different material.

[0122] 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 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 adjacent second electrodes 13 across a first disconnection portion 111a provided on the first electrode 11.

[0123] The first connection electrode 61a and the second connection electrode 61b are arranged parallel to each other at a constant distance (Cdd). 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.

[0124] Since wiring material 25 is located on such connection electrode portion 61, the line width (Cwd) of connection electrode portion 61 is preferably equal to or larger than the line width (Bw) of wiring material 25, and smaller than the vertical width of pad portion .

[0125] Second wiring member 23 is located on first connection electrode 61a, and first wiring member 11 is located on second connection electrode 61b.

[0126] A conductive layer 41 is located between the connection electrode 61 and the wiring member 25 to ensure a good connection between them. Optionally, the conductive layer 41 can be omitted, in which case the wiring member 25 is soldered directly to the connection electrode 61. Optionally, a solder paste can also be used to connect them.

[0127] A method for manufacturing such a solar cell module will be described below with reference to FIG.

[0128] In step S11, an insulating adhesive is applied to form an insulating layer at each disconnected point. The insulating adhesive is a viscous liquid such as epoxy. It is a material that is made of a silicone-based or silicone-based synthetic resin as the main ingredient, mixed with a hardener, filler, reinforcing agent, etc. This insulating adhesive can be applied to the disconnected points using well-known techniques such as screen printing, inkjet printing, and dispensing.

[0129] This insulating adhesive is applied in an island shape to the non-connection points of the wiring material 25 so that the wiring material 25 is not connected to either the first electrode 11 or the second electrode 13, as in the pattern shown in FIG.

[0130] In the process temperature conditions, the curing temperature varies depending on the material that makes up the insulating adhesive, and the melting temperature at which the insulating adhesive melts after curing is the same as that of the conductive adhesive. The curing temperature of the insulating adhesive must be higher than the curing temperature of the wiring material. Preferably, the curing temperature of the insulating adhesive is higher than 210°C and lower than 250°C, and the melting temperature is 400°C or higher.

[0131] After the insulating adhesive is applied, it is exposed to a temperature equal to or higher than the curing temperature to cure the insulating adhesive and form an insulating layer.

[0132] This step (S11) can be omitted depending on the configuration of the solar cell module. For example, among the embodiments of the solar cell module described above, in the embodiment 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.

[0133] In step S12, a conductive adhesive is applied to form a conductive layer at each connection point. The conductive adhesive is a viscous liquid called epoxy. It is a material that contains a hardener, filler, reinforcing agent, etc., mixed with a silicone-based or silicone-based synthetic resin as the main ingredient, and further contains conductive particles. The conductive particles are metal materials with chemical formulas such as Ni, Al, Ag, Cu, Pb, Sn, SnIn, SnBi, SnPb, Sn, SnCuAg, and SnCu, or a mixture 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 its melting temperature, the solder particles in the solder paste melt and fuse the two base materials together.

[0134] Similarly, the conductive adhesive can be applied to the connection points by well-known techniques such as screen printing, ink jetting, or dispensing.

[0135] 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.

[0136] Regarding the process temperature conditions, the curing temperature varies depending on the material constituting the conductive adhesive, just like the insulating adhesive, but must be at least lower than the melting temperature of the insulating layer 43. Furthermore, the melting temperature at which the conductive adhesive melts after curing must be higher than the curing temperature of the wiring material.

[0137] Preferably, the curing temperature of the conductive adhesive is the same as the lamination temperature in step S15. In this way, by setting the curing temperature of the conductive adhesive to be the same as the lamination temperature in step S15, the conductive adhesive can be cured in step S15 rather than immediately after being applied, which reduces the number of processes and reduces the possibility of thermal deformation because the solar cell is not exposed to high temperatures multiple times.

[0138] 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 like the conductive adhesive without curing in step S11, thereby reducing the need for two curing processes (insulating adhesive and conductive adhesive).

[0139] 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.

[0140] Next, in step S13, the first wiring members 21 and the second wiring members 23 are loaded. As shown in Fig. 8, the first wiring members 21 and the second wiring members 23 are arranged in a manner that connects two adjacent solar cells in the length direction, and the first wiring members 21 and the second wiring members 23 are alternately arranged in a direction intersecting the length direction.

[0141] 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), tape can be used, which is either a liquid tape applied with a liquid material or a solid tape with an adhesive applied to a film. Liquid tape can be formed by applying a liquid material onto the first wiring member 21 and second wiring member 23 using a dispenser and then immediately irradiating the liquid material with UV light to harden it, or it can be formed by applying a liquid material using a method such as screen printing or inkjet printing and then thermally hardening it. Epoxy-based or silicone-based synthetic resins can be used as the liquid material.

[0142] The tape may be attached in any shape as long as it is attached in a direction intersecting the wiring material 25 to facilitate fixing of the wiring material 25. For example, tape may be attached to the entire rear surface of the solar cell where the wiring material is located to protect the solar cell from moisture, or if the conductive adhesive or insulating adhesive has not yet hardened, tape may be attached in such a way that some of it is exposed.

[0143] On the other hand, the wiring material 25 may be temporarily fixed at a curing temperature, for example, 90 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.

[0144] In step S15, the encapsulant and transparent substrate are placed on top of the modularized solar cell, and the encapsulant and backsheet are placed underneath, and then these are packaged by thermocompression bonding in a laminating device. The heat treatment temperature is 145 to 165 degrees Celsius. At this time, the electrodes are all fixed with tape during lamination, which prevents the electrodes from warping during the lamination process.

[0145] 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-described embodiments, but can be similarly applied to other embodiments not described.

[0146] 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.

[0147] As shown in FIGS. 24 and 25, first electrodes 11 and second electrodes 13 are alternately arranged in the horizontal direction, and first wiring members 21 and second wiring members 23 are alternately arranged in the vertical direction.

[0148] Conductive layers 41 and insulating layers 43 are located along each of the connection points and non-connection points, selectively connecting or insulating the wiring material 25 and the electrodes (11, 13) at the intersections.

[0149] The dispersion layer 45 is laterally located between the conductive layer 41 and the insulating layer 43, and is formed separately from them to attach the wiring material 25 to the substrate. Preferably, such a dispersion layer 45 is formed between each conductive layer 41 and insulating layer 43, but it can be selectively formed as needed.

[0150] 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.

[0151] Although the vertical width (Spv) is shown in the figure as being larger than the line width (Bw) of the wiring material 25, the vertical width (Spv) of at least the dispersion layer 45 should be larger than the line width of the wiring material 25 in this way in order to stably attach the wiring material 25 to the substrate.

[0152] 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).

[0153] In consideration of the manufacturing process, it is desirable that the dispersion layer 45 is formed simultaneously with the formation of 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.

[0154] 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, if the dispersion layer 45 is formed from a conductive material, there is a risk of short circuits. However, if the dispersion layer 45 is formed on the insulating layer 43, the dispersion layer 45 can be formed without these risks.

[0155] Meanwhile, the dispersion layer 45 thus formed preferably has a larger application area per wire than the conductive layer 41 or insulating layer 43. Stress transmitted from the wiring material 25 is transmitted to the intersections and destroys the physical bond between the electrodes and the wiring material, but if the application area of ​​the dispersion layer 45 is larger than that of the conductive layer 41 or insulating layer 43, the stress is transmitted more to the dispersion layer 45 than to the intersections. Therefore, the stress transmitted to the conductive layer 41 or insulating layer 43 is reduced compared to before, thereby alleviating the above-mentioned problems.

[0156] FIG. 26 shows how a dispersion layer is formed when an electrode includes a broken portion, and FIG. 27 shows a cross section taken along line VII-VII' in FIG.

[0157] In the disconnection portion 111 shown in FIGS. 26 and 27, the electrodes (11, 13) are disconnected at a portion where the electrodes (11, 13) are missing for a certain width (Cw) in the longitudinal direction of the electrodes (11, 13).

[0158] The 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 of the first electrode 11, and the second disconnected portion 111b is formed at each non-connected point of the second electrode 13.

[0159] Conductive layers 41 are located along the connection points to electrically connect the wiring material and the electrodes.

[0160] 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.

[0161] The dispersion layer 45 is formed in the disconnection portion 111 in this manner, and is positioned 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 or the distance between the second electrodes 13, which form connection points with the wiring 25. The vertical width (Spv) of the dispersion layer 45 should be larger than the line width of the wiring 25 to ensure stable attachment of the wiring 25 to the substrate.

[0162] Figure 28 shows an example in which a plurality of dispersion layers are formed. In Figure 27, the dispersion layer 45 is composed of first to third dispersion layers (45a-45c). In the figure, the first to third dispersion layers (45a-45c) are shown to be all the same size, but they can also be configured to have different sizes depending on the selection.

[0163] 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 will be described. Although there are differences in the structure of the solar cell compared to the above-mentioned embodiment, the inclusion of a pad portion and the size of the pad portion are the same as the above-mentioned embodiment, and the technical concept is the same.

[0164] FIG. 29 is a perspective view showing the overall appearance of a solar cell module that 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. 31 29 is a cross-sectional view taken along the line XII-XII' in FIG. 29, and FIG. 32 is a view showing the state of the wiring material. Shows.

[0165] 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).

[0166] 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) to 200 (μm).

[0167] 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. For example, if the semiconductor substrate 111 is a p-type semiconductor substrate, the first electrode 113 collects electrons.

[0168] 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.

[0169] 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.

[0170] Between the semiconductor substrate 111 and the first electrode 113, and between the semiconductor substrate 111 and the second electrode 115, there are an emitter layer and a back surface field region that lower the potential barrier, and a passivation film that prevents charges from recombining from the surface, but these components are omitted from the figure.

[0171] In the solar cell having such a configuration, two adjacent solar cells are connected by a plurality of wiring members 125 .

[0172] The number of such wiring members 125 may be between 30 and 60, and each wiring member 125 has a wire shape with a circular cross section as shown in (A) of Figure 32. (B) of Figure 32 shows the cross-sectional shape of the wiring member 125.

[0173] As shown, the wiring material 125 has a cross-sectional view in which the coating layer 125a coats the core layer 125b to a thin thickness, for example, 12 μm, and has an overall thickness of 250 μm to 500 μm.

[0174] The core layer 125b is made of a metal with good conductivity such as Ni, Cu, Ag, or Al, and the coating layer 125a includes a metal material, particularly a solder, having a chemical formula such as Pb, Sn, SnIn, SnBi, SnPb, Sn, SnCuAg, or SnCu, and can be physically and electrically connected to other metals through soldering.

[0175] 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 material 125 may vary depending on the size of the semiconductor substrate and the line width, thickness, pitch, etc. of the electrodes.

[0176] Although the above description is based on the fact that the lead 125 is a wire having a circular cross section, the cross section may have various shapes such as a rectangular or oval shape.

[0177] 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 method for connecting electrodes and wiring material is soldering, which melts and bonds materials.

[0178] 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.

[0179] The first pad portion 140 widens the area where the first electrode 1130 and the wiring 125 intersect, thereby reducing contact resistance when connecting the wiring 125 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 added.

[0180] Furthermore, in order to further improve physical bonding strength and contact resistance while minimizing banding between the wiring material 125 and the semiconductor substrate, at least one pad portion of the first pad portion 140 may be different in size from the remaining pad portions. Here, different pad sizes refer to pad portions having different widths or lengths. Therefore, the first pad portion 140 may include at least one pad portion having different widths or lengths. This will be described later.

[0181] The number of the first pad units 140 may be six or more and may be less than the number of the first electrodes 113 .

[0182] 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.

[0183] 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 the coating layer 125a of the wiring 125 is heated to a temperature above its melting point for several seconds. As the coating layer 125a melts and cools, the wiring 125 is attached to the electrodes.

[0184] In an alternative example, the wiring material 125 can be attached to the electrode with a conductive adhesive. The conductive adhesive is an epoxy-based synthetic resin or a silicon-based synthetic resin with Ni, A. Liquids containing conductive particles such as l, Ag, Cu, Pb, Sn, SnIn, SnBi, SnPb, Sn, SnCuAg, and SnCu are The wiring material 125 is a material that hardens when heat is applied. The wiring material 125 can also be attached using solder paste. Solder paste is a paste containing solder particles containing lead (Pb) or tin (Sn). When heat is applied above the melting temperature, the solder particles in the solder paste melt, melting and bonding the two base materials.

[0185] Various aspects of the first electrode will be described below with reference to FIGS.

[0186] FIG. 33 shows the state of the first electrode in the first embodiment among various embodiments.

[0187] In FIG. 33, the first electrode 1130 includes a collecting electrode 1131 and a connecting electrode 1133 .

[0188] The collecting electrodes 1131 have a uniform width, extend long in one direction, and are arranged parallel to adjacent electrodes to form a stripe array. The collecting electrodes 1131 have a width of 30 μm to 100 μm, a thickness of 15 μm to 30 μm, and a pitch (P1), which is the distance between electrodes, of 1.2 mm to 2.2 mm.

[0189] The connecting electrodes 1133 also have a certain line width and extend long in a direction intersecting with the collecting electrodes 1131 to electrically and physically connect the collecting electrodes 1131 .

[0190] The connecting electrodes 1133 are substantially the same as or wider than the collecting electrodes 1131, with 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, except that the pitch (P2) is 5 mm-23 mm, which is larger than the pitch (P1) of the collecting electrodes 1131 and is less than 10 times smaller.

[0191] Alternatively, the connecting 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 (w1) of the first pad portion 140.

[0192] At the point where the collecting electrode 1131 and the connecting electrode 1133 intersect, a first pad portion 140 is selectively formed.

[0193] As in the previous embodiment, the first pad portion 140 forms an area where the electrode meets the wiring member 125, thereby enabling good bonding between the electrode and the wiring member 125. While it is preferable to form the first pad portion 140 at every intersection, it is also possible to selectively form the first pad portion 140 only at even-numbered columns or odd-numbered columns, or to form the first pad portion 140 at different rows according to a certain rule. It is also possible to selectively form the first pad portion 140 at every intersection or to arrange it randomly.

[0194] 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.

[0195] Experimental results showed that when the collection electrode 1131, connection electrode 1133, and first pad portion 140 were fabricated within the ranges described in this specification, the solar cell exhibited the most ideal efficiency, and when any one of them was outside the ranges described, the desired efficiency was not achieved.

[0196] The collecting electrode 1131, the connecting electrode 1133, and the first pad portion 140 configured as described above can be simultaneously formed by a screen printing method, in which case they are all made of the same material, for example, silver (Ag). Alternatively, each component can be configured separately as needed.

[0197] The wiring member 125 is located directly above the connection electrode 1133 and extends in a direction parallel to the connection electrode. Therefore, the wiring member 125 and the connection electrode 1133 face each other. The wiring member 125 has a line width (Da) of 250 μm to 500 μm.

[0198] 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.

[0199] Meanwhile, the collecting electrode 1131 may be configured to further include a disconnection portion 114, as in the second embodiment illustrated in Figure 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 when the pitch of the connecting electrodes 1133 is 10-14 mm, the width (Cw) of the disconnection portion 114 may be 1.5-1.8 mm, but the width (Cw) of the disconnection portion 114 can vary within the range of 1.5 to 3.2 mm.

[0200] In this embodiment, the disconnection portions 114 are formed every two rows, but this can be changed in various ways as desired. For example, the disconnection portions 114 can be formed every row, every three rows, or randomly. Also, in this embodiment, the disconnection portions 114 are formed between the connection electrodes, but this can also be formed in various positions as desired.

[0201] In this embodiment, the first pad portions 140 are connected to a connection electrode and the wiring material 125 is soldered thereon, so there is no problem of reduced efficiency of the solar cell due to the disconnection portion 114. In fact, the inclusion of the disconnection portion 114 in the first electrode 113 can reduce manufacturing costs.

[0202] FIG. 35 shows a pad portion 140 and an assistant pad portion 141 between the pad portions. 10 shows the first electrode of the third embodiment further formed.

[0203] As shown in FIG. 35, in the solar cell module according to the present invention, at least one of the plurality of first pad portions 140 provided in each solar cell may be different in size from the remaining pad portions.

[0204] 35, at least one pad portion may be a relatively small auxiliary pad portion 141. The remaining pad portions may be pad portions 140 that are relatively larger than the auxiliary pad portion.

[0205] 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 the intersection between the first pad portions 140 in the vertical direction to connect the wiring material 125 and the connection electrode 1133.

[0206] 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 adhesive resin containing conductive metal particles.

[0207] The width (w2) of the auxiliary pad portion 141 is preferably equal to or smaller than the line width (Da) of the wiring material 125.

[0208] The size of the auxiliary pad portion 141 is also determined in consideration of various variables, similar to the first pad portion 140. be adjusted appropriately.

[0209] In Figure 35, the auxiliary pad portions 141 are shown as being formed every two rows between the first pad portions 140, but they can also be formed in various forms, such as being formed every row or in triplicates.

[0210] Figure 36 shows another example of an auxiliary pad 142 according to the fourth embodiment. The auxiliary pad 141' shown in Figure 35 is formed at an intersection, but the auxiliary pad 142 in Figure 36 differs only in that it connects the collecting electrodes 1131 of two adjacent lines.

[0211] 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. This increases the contact area between the wiring 125 and the first electrode 1130, thereby reducing contact resistance and increasing bonding strength.

[0212] FIG. 37 is a diagram showing a part of a first electrode according to a fifth embodiment of the front electrode.

[0213] In this embodiment, the first electrode 1130 includes a ladder electrode 1135 and a wiring electrode 1137 .

[0214] The ladder electrode 1135 has a ladder shape including a pair of legs 1135a and a connecting portion 1135b connecting the legs 1135a to each other.

[0215] The legs 1135a are spaced apart from each other by a fixed 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 140. Preferably, the distance (SA) is 0.3 to 0.7 compared to the pitch (PD) of the lead.

[0216] The connecting portion 1135b connects 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.

[0217] The legs 1135a and connecting portions 1135b that make up the ladder electrode 1135 in this way have a line width of 30 μm-120 μm, similar to the width of the collecting or connecting electrodes.

[0218] 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 also has a line width of 30 μm to 120 μm.

[0219] Meanwhile, a wiring member 125 is positioned along the center of the ladder electrode 1135 and connected to the ladder electrode 1135. A first pad portion 140 is selectively positioned at a position opposite the wiring member 125, and an extension electrode 144 connects the first pad portion 140 to the first pad portion 140.

[0220] The first pad portion 140 is the same as that in the first embodiment described above, and therefore a detailed description thereof will be omitted here.

[0221] 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 the portion that is fused 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 the portion where the wiring 125 and the first electrode 1130 face each other, the bonding area between the wiring 125 and the first electrode 1130 is increased, thereby increasing the bonding strength and reducing the contact resistance.

[0222] In this embodiment, the ladder electrode 1135, the wiring electrode 1137, the first pad portion 140, and the extension electrode 144 can all be formed 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.

[0223] 38 and 39 show a state in which auxiliary pads are formed between pads instead of the extended electrodes 144. The only difference compared to FIG. 37 is that auxiliary pads (141, 142) are located between the first pads 140 instead of the extended electrodes 144 connecting the pads between the first pads 140.

[0224] Similarly, the auxiliary pad portion 141 can increase the contact area with the wiring material 125, thereby reducing the contact resistance and increasing the bonding strength. In addition, since it is formed with a smaller area than the extension electrode 144, it is also expected to have the effect of reducing manufacturing costs.

[0225] 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.

[0226] FIG. 40 shows a first electrode in which the first pad portion includes an expanded pad portion 140e having a first size and an auxiliary pad portion 140a having a second size smaller than the first size.

[0227] In this embodiment, the first electrode 1130 includes a collecting electrode 1131 and a connecting electrode 1133 as described above.

[0228] The plurality of first pad portions 140 may selectively include an expansion pad portion 140e and an auxiliary pad portion 140a at a position where the lead 125 passes among the intersections of the collecting electrodes 1131 and the connecting electrodes 1133.

[0229] Here, the auxiliary pad portion 140a of the first pad portion 140 may have a first size, and the expanded pad portion 140e may have a second size larger than the first size. That is, the width and length of the expanded pad portion 140e may be larger than the width and length of the auxiliary pad portion 140a.

[0230] The auxiliary pad portion 140a may be located between the pair of extended pad portions 140e in the length direction of the wiring material.

[0231] 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 along the length direction of the wiring material 125 in each of the plurality of solar cells from the position of the auxiliary pad portion 140a.

[0232] As an example, the extended pad portion 140e may be formed on the outermost collecting electrode 1131 of the first electrode 1130 that intersects along the length direction of the wiring material 125 on the front surface of each semiconductor substrate 15 of the plurality of solar cells.

[0233] Therefore, the expansion pad portion 140e is formed at the first and last positions 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 expansion pad portion 140e is not necessarily limited to being formed at the first and last positions of the semiconductor substrate 15 along the length of the wiring member 125, and instead, a plurality of expansion pad portions 140e may be formed at the first and last positions of the semiconductor substrate 15 along the length of the wiring member 125.

[0234] The auxiliary pad portions 140a are formed at every intersection between the extended pad portions 140e, or are arranged intermittently in two or four lines as necessary. The number of auxiliary pad portions 140a is determined based on the required bonding strength and production cost, as this is related to the bonding strength of the wiring material 125 and the production cost. Preferably, one auxiliary pad portion 140a is formed for every 1 to 10 lines based on the collecting electrodes 1131, and the total number is 6 to 48.

[0235] Furthermore, the width of the extended pad portion 140e may be greater than the line width of the wiring material 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.

[0236] For example, the size of the extended pad portion 140e is 0.25 mm to 2.5 mm in width (direction intersecting the length direction of the wiring material) and 0.035 mm to 30 mm in length (direction extending the wiring material), more preferably 0.4 mm to 6 mm. The width of the auxiliary pad portion 140a may be 0.035 mm to 30 mm, preferably 0.25 mm to 2.5 mm, and the length of the auxiliary pad portion 140a may be 0.1 mm to 1 mm.

[0237] 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.

[0238] Therefore, if the size of the expansion pad portion 140e is larger than the size of the auxiliary pad portion 140a, the length is the same and the width is larger, or if the width is the same and the length is longer, then both the width and length can be larger, and in this embodiment, when the size is larger, both cases are included.

[0239] 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 way.

[0240] 41, the second electrode 1150 may be configured to include a plurality of collecting electrodes 1151 formed in parallel to each other and a connecting electrode 1153, similar to the front electrode 1130. Here, the connecting electrode 1153 may be omitted.

[0241] Here, the collecting electrode 1151 may be formed in a direction intersecting the length direction of the lead 125 .

[0242] The collecting electrode 1151 of the second electrode 1150 may include a plurality of second pad portions (140e', 140a') formed in the area where the lead 125 and the collecting electrode 1151 intersect.

[0243] 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 collecting electrodes 1151 of the second electrode 115.

[0244] 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 expanded pad portion 140e' may be larger than 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'.

[0245] In addition, among the second pad portions (140e', 140a'), the extended pad portion 140e' may be located in an area outside the rear surface area of ​​the semiconductor substrate 15 along the length direction of the wiring material 125 in each of the plurality of solar cells from the position of the auxiliary pad portion 140a'.

[0246] 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 intersects along the length direction of the wiring material 125 from the rear surface of each semiconductor substrate 15 of the plurality of solar cells.

[0247] Therefore, the extended pad portion 140e' is formed at the first and last 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 last end of the semiconductor substrate 15 along the length of the wiring member 125 as shown in Fig. 41, and instead, a plurality of extended pad portions 140e' may be formed at the first and last end of the rear region of the semiconductor substrate 15 along the length of the wiring member 125.

[0248] In this way, when the rear electrode is formed to include an extended pad portion 140e' and an auxiliary pad portion 140a', just like the front, 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').

[0249] 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 plurality of first pad portions 140e and 140a may be smaller than the size of each of the plurality of second pad portions 140e' and 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.

[0250] Furthermore, 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.

[0251] 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 and may be longer than the first pad portions (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, preferably about 5.5 to 7.5 mm, and the length of the auxiliary pad portion 140a' may be between 0.2 to 3 mm, preferably about 0.6 to 1.2 mm.

[0252] Since the front surface is the surface through which light enters, if the size of the pad portion formed on the rear surface is increased, 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.

[0253] 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 five times the line width.

[0254] 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 appearance 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 appearance of wiring material in the solar cell module shown in Fig. 42.

[0255] 42 to 45, in the solar cell module of this embodiment, a plurality of solar cells arranged adjacent to each other are connected by a plurality of 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).

[0256] The solar cell has a thin thickness and a rectangular shape with beveled or rounded corners, and its horizontal and vertical dimensions are approximately 156 (mm) x 156 (mm), and its thickness is 150 (μm) - 200 (μm).

[0257] A first electrode 113 is located on the front surface, which is the surface onto which light is incident, and is connected to the wiring material 125 via a first pad portion 140. The first electrode 113 collects charges of opposite conductivity to that of the semiconductor substrate 111. For example, if the semiconductor substrate 111 is a p-type semiconductor substrate, the first electrode 113 collects electrons.

[0258] 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.

[0259] A second electrode 115 having a similar shape to the first electrode 113 is located on the rear surface of the semiconductor substrate 111 and is connected to the wiring member 125 via a second pad portion 160. The second electrode 115 collects charges of opposite conductivity to that of the first electrode 113.

[0260] The first electrode 1130 and the second electrode 1150 will be described in detail below with reference to different drawings.

[0261] A back surface field region 154 is located between the second electrode 1150 and the semiconductor substrate 111, and this back surface field region 154 is formed only locally in a region corresponding to the second electrode 115, where the impurities having the same conductivity as the semiconductor substrate 111 are doped at a higher concentration than the substrate 111.

[0262] The back surface field region 154 has the same conductivity type as the substrate. 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 ion plating, which is one of the ion implantation methods.

[0263] This back surface field region 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 back surface side and preventing recombination of different charges on the substrate surface.

[0264] In this embodiment, the back surface field region 154 is not formed on the entire back surface of the substrate, but is formed only on some electrodes. However, it is also possible to form the back surface field region 154 on the entire back surface of the semiconductor substrate 111.

[0265] In the solar cell having such a configuration, two adjacent solar cells are connected by a wiring member 125 .

[0266] The wiring member 125 has a wire shape as shown in (A) of Figure 45. (B) of Figure 45 shows the cross-sectional shape of the wiring member 125.

[0267] As shown, the wiring material 125 has a cross-sectional view in which a coating layer 125a coats a core layer 125b with a thin thickness (approximately 12 μm), and has an overall thickness of 250 μm to 550 μm.

[0268] The core layer 125b is made of a metal with good conductivity such as Ni, Cu, Ag, or Al, and the coating layer 125a includes a metal material, particularly a solder, having a chemical formula such as Pb, Sn, SnIn, SnBi, SnPb, Sn, SnCuAg, or SnCu, and is therefore solderable.

[0269] When connecting two adjacent solar cells, 10-15 pieces of this wiring material 125 are used if the semiconductor substrate has a size of 156mm x 156mm, and are adjusted using variables such as the size of the substrate, the line width, thickness, and pitch of the electrodes, and the thickness of the wiring material.

[0270] Although the above description is based on the fact that the lead 125 has a wire shape with a circular cross section, the cross section may have various shapes such as a rectangle or an oval.

[0271] The 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 made of adhesive synthetic resin containing conductive particles is also possible. do.

[0272] In this embodiment, a first pad portion 140 and a second pad portion 160 are further positioned at the intersection of the first electrode 1130 and the wiring 125. These first and second pad portions (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 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).

[0273] In one example of a soldering method, wiring 125 is placed on the front and rear surfaces of two adjacent solar cells, facing the first electrode 1130 and the second electrode 1150, respectively, and then the coating layer 125a of 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 wiring 125 is attached to the electrodes.

[0274] In this embodiment, a reflector 170 is further positioned between the solar cells. The solar cells are spaced a certain distance apart from adjacent solar cells in the length direction of the wiring material 125, and an inter-section (IA) exists between the solar cells. The reflector 170 is positioned in the inter-section (IA) and scatters light incident on the inter-section (IA) so that the light can be incident on the adjacent solar cell.

[0275] Hereinafter, the first electrode 1130 of the solar cell module configured as above will be described in more detail with reference to FIG.

[0276] In this embodiment, the first electrode 1130 includes a collecting electrode 1131 and a connecting electrode 1133 .

[0277] The collecting electrodes 1131 have a certain width and extend in one direction, for example, in a direction intersecting the extension direction of the wiring material 125, and are arranged parallel to adjacent electrodes to form a stripe array. The collecting electrodes 1131 have a width of 35 μm to 100 μm, and the pitch (Pf), which is the distance between electrodes, is 1.2 mm to 2.2 mm. The numerical ranges presented here are only preferred examples, and the numerical ranges may be adjusted to accommodate various variables.

[0278] The connection electrodes 1133 also have a certain 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.

[0279] 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.

[0280] Alternatively, the connecting 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 .

[0281] The connecting electrode 1133 having such a configuration is not necessarily a necessary configuration, so the first electrode 1130 can also be configured with only the collecting electrode 1131 without this connecting electrode 1133 .

[0282] 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.

[0283] A first pad portion 140 is selectively formed at the intersection of the collecting electrode 1131 and the connecting electrode 1133. The vertical width (wfv) of the first pad portion 140 is larger than the line width of the collecting electrode 1131 but 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 but smaller than 2.5 mm, for example, between 0.25 mm and 2.5 mm.

[0284] In a preferred embodiment, it is desirable to form the first pad unit 140 at every intersection, but depending on manufacturing cost, efficiency, etc., one first pad unit 140 may be disposed at equal intervals for each of a plurality of collecting electrodes based on one line of the connection electrode 1133. In the drawing, an example is shown in which the first pad unit 140 is formed at an intersection for every 2*n (n = natural number) lines in the extension direction of the connection electrode 1133.

[0285] 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.

[0286] 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). Alternatively, each component can be individually configured as needed.

[0287] The wiring member 125 is located directly above the connection electrode 1133 and extends in a direction parallel to the connection electrode. Therefore, the wiring member 125 and the connection electrode 1133 face each other. The wiring member 125 has a line width (Da) of 250 μm-500 μm, which is smaller than the width (wfh) of the first pad portion 140.

[0288] 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 solar cell, and may also increase the bonding strength of the wiring material.

[0289] The second electrode 115 will be described in detail below with reference to FIG.

[0290] In this embodiment, the second electrode 1150, like the first electrode 1130, 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 will be 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 will be referred to as the rear collecting electrode, and the connecting electrode 1153 will be referred to as the rear connecting electrode.

[0291] The rear collecting electrodes 1151 have a constant line width and are strip-shaped, extending long in one direction, for example, a direction intersecting the extension direction of the wiring material 125, and are arranged parallel to adjacent ones to form a stripe arrangement.

[0292] The rear collecting electrodes 1151 may have a line width of 35 μm-120 μm and a pitch (Pb) of 1.2 mm-2.2 mm, similar to the front collecting electrodes 1131. In another preferred embodiment, the line width of the rear collecting electrodes 1151 may be larger than that of the front collecting electrodes 1131, or the pitch of the rear collecting electrodes 1151 may be smaller than that of the front collecting electrodes 1131.

[0293] In this way, the rear collecting electrode 1151 can be made thicker than the front collecting electrode 1131 .

[0294] Also, the series resistance of the front surface is high at about 120-140 (Ω / sq), while that of the rear surface is lower at about 20-40 (Ω / sq). Therefore, the front collecting electrode 113 requires a relatively larger number of pad portions than the rear surface to increase the contact area with the wiring. As a result, the pitch of the front collecting electrodes 1131 becomes larger than that of the rear surface, and the number of rear collecting electrodes 1151 may be greater than that of the front collecting electrodes 1131.

[0295] On the other hand, the figure shows that the line widths of the front collecting electrode 1131 and the rear collecting electrode 1151 are the same.

[0296] The rear connection electrode 1153 also has a certain line width and extends long in a direction intersecting with the rear collecting electrode 1151, i.e., in the same direction as the extension direction of the wiring material 125, to electrically connect the rear collecting electrode 1151.

[0297] 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 pitch (Bdb) on the front surface.

[0298] 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 .

[0299] The rear connection electrode 1153 is not an essential component, and the second electrode 115 may also be formed of only the collecting electrode 1151. Omitting the rear connection electrode 1153 may increase the area onto which light is incident, and from the manufacturer's perspective, it may reduce material costs and manufacturing costs.

[0300] A second pad portion 160 is selectively formed at the intersection of the rear collecting electrode 1151 and the rear connecting electrode 1153, 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 larger than the first pad portion 140. For example, the width of the second pad portion 160 may be between 0.25 mm and 2.5 mm, and the length of the second pad portion 160 may be between 0.1 mm and 12 mm.

[0301] 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 different.

[0302] 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. This 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 doped with a high concentration of 2*1020 (atoms / cm3).

[0303] In this embodiment, the back surface field portion 154 is formed locally only for the collecting electrode 1151, and therefore, like the collecting electrode 1151, the back surface field portion 154 is also spaced a certain distance from the adjacent one, forming a stripe arrangement overall.

[0304] In this way, a collecting electrode 1151 is formed on the rear surface of the semiconductor substrate 111, with the heavily doped rear field region 154 as an interface. When measured with a measuring device, the series resistance on the rear side is 20-40 (Ω / □), while the front side is about three times larger, at 120-140 (Ω / □).

[0305] This fact refutes the idea that the contact resistance between the wiring 125 and the electrode is much greater on the front side than on the rear side. Experiments conducted by the inventors have shown that reducing the number of second pad portions 160 to 1 / 2 of the first pad portions 140 does not affect the efficiency of the solar cell. However, when the number of second pad portions 160 becomes less than 1 / 2 of the first pad portions 140, the efficiency of the solar cell decreases sharply.

[0306] In this embodiment, the number of second pad units 160 is configured to be less than the number of first pad units 140, thereby effectively reducing the manufacturing cost while maintaining the efficiency of the solar cell.

[0307] The rear collecting electrode 1151, rear connecting electrode 1153, and second pad portion 160 can be simultaneously formed by screen printing, in which case they are all made of the same material, for example, silver (Ag). Alternatively, each component can be individually configured as needed.

[0308] The wiring material 125 is located directly above the rear connection electrodes 1153 and is formed long in a direction parallel to the rear connection electrodes 1153, and the pitch of the wiring material is substantially the same as the pitch (Bdb) of the connection electrodes 1153.

[0309] Even on the rear side, the wiring material 125 is soldered while being placed on the rear connection electrode 1153 in this manner, so 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.

[0310] As described above, in this embodiment, the second pad portions 160 are formed in fewer numbers than the first pad portions 140, so the positions of the first pad portions 140 and the second pad portions 160 form various arrangements according to the positions of the first electrodes and second electrodes. In this regard, please refer to Figures 48 to 51.

[0311] In this drawing, only the components necessary for explanation are shown in a simplified manner, with dashed and dotted lines indicating front collecting electrode 1131, dotted lines indicating rear collecting electrode 1151, and two-dot chain lines indicating wiring 125. It is also assumed that wiring 125 is positioned 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.

[0312] First, FIG. 48 shows a case where the pitches of front collecting electrodes 1131 and rear collecting electrodes 1151 are the same and front collecting electrodes 1131 and rear collecting electrodes 1151 are positioned on the same line.

[0313] The first pad portions 140 are formed at intervals of multiples of two, and there is one intersection where there is no first pad portion 140 in the extension direction of the wiring material 125. The second pad portions 160 are formed at intervals of multiples of four, and there are three intersections between them where there is no second pad portion 160. As a result, the pitch (Pdf), which is the distance between the first pad portions 140, is smaller than the pitch (Pdb) of the second pad portions 160.

[0314] On the other hand, 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.

[0315] In comparison, Figure 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 Figure 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.

[0316] FIG. 50 shows a case where the pitch of the front collecting electrodes 1131 and the back collecting electrodes 1151 is the same, but the front collecting electrodes 1131 and the back collecting electrodes 1151 are not collinear.

[0317] 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 lead 125. The first pads 140 are formed in multiples of two, and the second pads 160 are formed in multiples of four, so the first pads 140 and the second pads 160 are not overlapping.

[0318] 51 shows a 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.

[0319] Therefore, the second pad section 160 may be positioned so as to overlap the first pad section 140, or may be positioned so as to overlap only partially with the first pad section 140, or may be positioned at a different position.

[0320] 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 centered on the inter section (IA), and Fig. 53 is a cross-sectional view taken along line CC in Fig. 52.

[0321] The second solar cell C2 is separated from the first solar cell C1 by an inter-section (IA) and connected to the wiring material 125. A reflector 170 is located in the inter-section (IA).

[0322] In this embodiment, the reflector 170 is a bar-shaped rectangular parallelepiped, and has good reflection. For example, the reflector 170 is made of the same material as the electrodes (113, 115) or the wiring material 125.

[0323] The reflector 170 is fixed to the wiring member 125, and is preferably soldered to the wiring member 125. In this case, when the wiring member 125 is soldered to the electrodes (113, 115), the reflector 170 is also soldered, thereby reducing the number of work steps and the manufacturing cost.

[0324] Preferably, the reflector 170 is connected to all of the wiring members 170 connecting two solar cells. In this embodiment, 12 wiring members 125 are used to electrically connect two solar cells (c1, c2), and the reflector 170 is soldered to all of the 12 wiring members.

[0325] 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 tilted 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 tilted at a predetermined angle.

[0326] Therefore, when light is incident on the inter section (IA), the light is reflected by the surface of the reflector 170 and is incident on the adjacent second solar cell C2.

[0327] FIG. 54 shows a state in which the reflector 170 is positioned further inward from the edge of the first solar cell and is connected to the wiring material.

[0328] 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.

[0329] 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.

[0330] In this embodiment, the reflector 170 is placed on the bent portion of the wiring 125, so that the problem of the wiring 125 being broken can be prevented.

[0331] FIG. 55 shows a state in which reflectors 170 are formed on the front and rear surfaces of the wiring 125 in the inter-section (IA).

[0332] 55, the same as described above, except that reflectors 170 are formed above and below the wiring 125. As such, the reflectors 170 are also formed below the wiring 125, which can prevent the wiring 125 from being broken in the inter section (IA). Furthermore, the reflectors 170 made of a metal material are further formed in the inter section (IA), which can reduce the line resistance of the wiring 125.

[0333] 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 from the surface of the reflector 170, it causes diffuse reflection, which can effectively increase the amount of light incident on the solar cell.

[0334] Figure 57 shows a state in which the surface of the reflector is made up of inclined surfaces (Cs) and unevenness 171 is formed on the inclined surfaces. Figure 56 illustrates an example in which the inclined surfaces (Cs) are rounded, but any shape is acceptable as long as the height varies depending on the position. If the surface of the reflector has inclined surfaces (Cs) in this way, light is further refracted from the surface of the reflector toward the solar cell in an amount corresponding to the inclination angle, thereby effectively increasing the amount of light incident on the solar cell.

[0335] The above description of the reflectors has been given taking the example of one reflector 170 being arranged in the inter section (IA), but at least two or more reflectors 170 may be arranged as shown in Figure 58. In this case, the multiple reflectors 170 may all be arranged as described in Figures 53 to 57, or each reflector may be configured in a different manner. As an example, if there are two reflectors 170 in the inter section (IA), one is configured as shown in Figure 55 and the other is configured as shown in Figure 57.

[0336] 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 the direction intersecting the wiring material.

Claims

1. a semiconductor substrate; and a plurality of solar cells including first electrodes for collecting charges of a first conductivity and second electrodes for collecting charges of a second conductivity, the first electrodes being formed on a rear surface of the semiconductor substrate in a first direction and 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 conductive layers, and insulated from the second electrodes, in order to connect the plurality of solar cells in series with each other; a second wiring member formed in the second direction, electrically connected to the second electrode by the conductive layer, and insulated from the first electrode, for connecting 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, A solar cell module, wherein the first pad portion or the second pad portion comprises a first contact pad portion and a second contact pad portion having a width greater than the width of the first and second electrodes, respectively, and the width of at least one of the second contact pad portions along the first direction is greater than the width of the first contact pad portion along the first direction.

2. 2. The solar cell module according to claim 1, wherein 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 includes a broken portion in which the electrode is partially broken.

3. The solar cell module according to claim 2 , wherein the width of the disconnection portion varies depending on the position of the disconnection portion in the first electrode or the second electrode.

4. The solar cell module according to claim 2 or 3, wherein a bank is formed in the disconnected portion, selectively wrapping the tip of the electrode.

5. The solar cell module according to any one of claims 1 to 4, wherein an insulating layer is 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.

6. 6. The solar cell module according to claim 1, wherein the first contact pad portion has a width greater than the widths of the first wiring member and the second wiring member.

7. A solar cell module described in any one of claims 1 to 6, wherein the width of the first pad portion and the second pad portion along the second direction is smaller than the distance between the first electrode and the second electrode, and the width of the first pad portion and the second pad portion along the first direction is smaller than the distance between the first wiring material and the second wiring material.

8. 8. The solar cell module according to claim 1, wherein at least one of the first pad portion and the second pad portion includes a slit formed in a groove shape.

9. The solar cell module according to any one of claims 1 to 8, wherein the size of the first pad portion or the second pad portion differs depending on the position at which the first pad portion or the second pad portion is formed.

10. The solar cell module according to any one of claims 1 to 9, wherein at least one of the first wiring member and the second wiring member includes a wrinkled buffer portion having peaks and valleys, and the length of the wiring member is increased by the buffer portion extending in the longitudinal direction.

11. A solar cell module as described in any one of claims 1 to 10, further comprising a plurality of connection electrodes that electrically connect a plurality of the first pad portions or a plurality of the second pad portions to the first electrode or the second electrode in the second direction in each of the plurality of solar cells.

12. 12. The solar cell module according to claim 1, wherein at least one of the first pad portion and the second pad portion is formed from the same material as the first electrode or the second electrode.

13. The solar cell module according to any one of claims 1 to 12, wherein at least one of the first pad portion and the second pad portion is formed from the first electrode or the second electrode and another conductive material.

14. 6. The solar cell module of claim 5, wherein each of the plurality of solar cells includes a plurality of 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.

Images