solar cell module

Abstract

Solar cell module, comprising a plurality of solar cells, each comprising a semiconductor substrate and first electrodes and second electrodes arranged alternately on a rear surface of the semiconductor substrate parallel to each other in a first direction; a plurality of first wiring elements arranged in a second direction that intersects the first direction, electrically connected to the first electrodes by a conductive layer, insulated from the second electrodes, and configured to connect the plurality of solar cells in series; and a plurality of second wiring elements arranged in the second direction, electrically connected to the second electrodes through the conductive layer, insulated from the first electrodes and configured to connect the plurality of solar cells in series, wherein each of the plurality of solar cells has first pads formed at intersections of the first wiring elements and the first electrodes, and second pads formed at intersections of the second wiring elements and the second electrodes, and wherein the first pads or the second pads have a first contact pad with a width greater than the width of each of the first and second electrodes, and at least one second contact pad with a larger size than the first contact pad.

Description

CROSS REFERENCE TO ASSOCIATED APPLICATION

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2014-0084829 filed on July 7, 2014 with the Korean Intellectual Property Office, No. 10-2014-0100083 filed on August 4, 2014 with the Korean Intellectual Property Office, No. 10-2014-0100084 filed on August 4, 2014 with the Korean Intellectual Property Office, and No. 10-2014-0136153 filed on October 8, 2014 with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTIONField of the invention

[0002] Embodiments of the invention relate to a solar cell module comprising a plurality of solar cells connected to one another by a plurality of wiring elements. Description of related technology

[0003] Since existing energy sources such as oil and coal are expected to be depleted soon, interest in alternative energy sources has recently increased. Among these alternative energy sources, solar cells for generating electrical energy from solar energy have come into particular focus, as solar cells use sunlight as a plentiful energy source and do not cause environmental pollution.

[0004] A solar cell generally comprises a conductive substrate containing p-type or n-type impurities, an emitter region and a backfield region, each more heavily doped with impurities than the substrate, and electrodes electrically connected to the emitter region and the backfield region, respectively. In this case, a pn junction forms between the substrate and the emitter region, generating electrical energy through a photoelectric effect.

[0005] When light falls on the solar cell, a plurality of electron-hole pairs are formed in the semiconductors. The electron-hole pairs are separated into electrons and holes. The electrons move to the n-type semiconductor, such as the emitter region, and are then collected by the electrodes connected to the emitter region, while the holes move to the p-type semiconductor, such as the backfield region, and are then collected by the electrodes connected to the backfield region. The electrodes are connected to each other by electrical wires to generate electrical current. SUMMARY OF THE INVENTION

[0006] Embodiments of the invention provide a solar cell module with improved efficiency.

[0007] In one aspect, there is a solar cell module comprising a plurality of solar cells, each comprising a semiconductor substrate and first electrodes and second electrodes alternately arranged on a rear surface of the semiconductor substrate in parallel with each other in a first direction; a plurality of first wiring elements arranged in a second direction crossing the first direction, electrically connected to the first electrodes via a conductive layer, insulated from the second electrodes, and configured to connect the plurality of solar cells in series;and a plurality of second wiring elements arranged in the second direction, electrically connected to the second electrodes via the conductive layer, insulated from the first electrodes, and configured to connect the plurality of solar cells in series, wherein each of the plurality of solar cells has first pads formed at the intersections of the first wiring elements and the first electrodes, and second pads formed at the intersections of the second wiring elements and the second electrodes, and wherein the first pads or the second pads have a first contact pad with a width larger than the width of each of the first and second electrodes, and at least one second contact pad with a size larger than the first contact pad.;

[0008] At least a portion of the second electrodes insulated from the first wiring elements or at least a portion of the first electrodes insulated from the second wiring elements may have an interruption portion in which the first electrodes or the second electrodes are not present.

[0009] A web may be arranged on the interruption section to selectively cover one end of the electrode.

[0010] An insulating layer may be formed in at least a portion of an insulating portion between a first electrode and a second wiring member or in at least a portion of an insulating portion between a second electrode and a first wiring member.

[0011] The first and second pads may be made of the same material as the first or second electrodes. In this case, at least one of the first and second pads may have a slot with a thin groove.

[0012] Alternatively, the first and second pads may be made of a different conductive material than the first or second electrodes.

[0013] Each of the first and second electrodes may have a width of 100 µm to 600 µm and a thickness of 0.1 µm to 10.0 µm.

[0014] Each of the first and second wiring elements may have a width of 1 mm to 50 mm and a thickness of 25 µm to 200 µm.

[0015] Each of the plurality of solar cells may include a plurality of dispersion layers disposed in a region between the insulating layer and the conductive layer and selectively securing the first wiring elements and the second wiring elements to the semiconductor substrate.

[0016] The majority of the dispersion layers may be made of the same material as the first or second electrodes or of the same material as the insulating layer or the conductive layer.

[0017] In another aspect, there is a solar cell module comprising a plurality of solar cells, each comprising a semiconductor substrate, first electrodes arranged parallel to each other on a front surface of the semiconductor substrate, and a second electrode arranged on a rear surface of the semiconductor substrate;and a plurality of wiring elements configured to connect the first electrodes of a first solar cell of the plurality of solar cells to the second electrode of a second solar cell adjacent to the first solar cell, wherein at least a portion of the first electrodes in each of the plurality of solar cells includes a plurality of first pads each having a width greater than a width of the first electrode at intersections of the wiring elements and the first electrodes, wherein a size of at least one of the first pads is different from a size of a remainder of the first pads;

[0018] The first pads may include an auxiliary pad having a first size and an extension pad having a second size larger than the first size.

[0019] The plurality of second electrodes may be arranged parallel to each other and may include a plurality of second pads at the intersections between the wiring elements and the second electrodes. The second pads may include an auxiliary pad and an extension pad, each of which has a different size.

[0020] For the second pads, the width or length of the extension pad can be greater than the width or length of the auxiliary pad.

[0021] In each of the first and second pads, the extension pad may be arranged closer to an end portion of the semiconductor substrate than to the auxiliary pad along a longitudinal direction of the wiring element in each of the plurality of solar cells. For example, in each of the first and second pads, the extension pad may be arranged at the outermost first electrodes among the first electrodes that cross the wiring elements along the longitudinal direction of the wiring element in each of the plurality of solar cells.

[0022] Alternatively, in each of the first and second pads, the extension pad and the auxiliary pad may be repeatedly arranged in a predetermined pattern along a longitudinal direction of the wiring member.

[0023] At least one of a width, a length, or a number of the first pads may be different from at least one of a width, a length, or a number of the second pads.

[0024] The number of first pads may be equal to or greater than six and may be equal to or less than the number of first electrodes. The number of second pads may be equal to or greater than six and may be equal to or less than the number of second electrodes. For example, the number of first pads may be greater than the number of second pads.

[0025] The solar cell module may further include a plurality of connection electrodes configured to electrically connect the first pads or the second pads to the first electrodes or the second electrodes in a direction of the wiring member in each of the plurality of solar cells.

[0026] The width of the plurality of connection electrodes may be equal to or greater than the width of the first electrodes or the second electrodes and may be smaller than the width of the first pads or the second pads.

[0027] A number of wiring elements may be 6 to 30, and each wiring element may have the shape of a wire with a circular cross-section and a diameter of 250 µm to 500 µm.

[0028] For the first pads or the second pads, a width of the extension pad may be larger than a width of the wiring element and less than 2.5 mm.

[0029] A length of the first pads or the second pads may be greater than a width of the first electrodes or the second electrodes and may be less than 30 mm.

[0030] A ratio (m / n) between a number (m) of the second pads and a number (n) of the first pads may be 0.5 ≤ m / n < 1.

[0031] A distance between the second pads may be greater than a distance between the first pads. A distance between the first electrodes may be equal to or greater than a distance between the second electrodes. Therefore, a number of second electrodes may be greater than a number of first electrodes.

[0032] The solar cell module may further comprise a reflector disposed between the first solar cell and the second solar cell and connected to the wiring elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are provided to provide a further understanding of the invention and are incorporated in this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings: Fig. 1 shows an entire shape of a solar cell module according to an embodiment of the invention; Fig. 2 is a cross-sectional view schematically showing a Fig. 1 shows the solar cell; Fig. 3 shows an entire shape of a wiring element of the Fig. 1 solar cell module shown; Fig. 4 is a cross-sectional view of a Fig. 3 wiring element shown; Fig. 5 shows another wiring element according to an exemplary embodiment of the invention; Fig. 6 is a cross-sectional view of a Fig. 5 wiring element shown; Fig. 7 shows a buffer formed on a wiring member; Fig. 8 shows a connection relationship between the electrodes of the individual solar cells and the wiring elements in the Fig. 1 solar cell module shown; Fig. 9 is a cross-sectional view taken along the Fig. 8 shown line I-I'; Fig. 10 is a cross section along the Fig. 8 shown line II-II'; Fig. 11 shows that a pad is formed at an intersection between an electrode and a wiring member; Fig. 12 is a cross-sectional view along the Fig. 11 shown line III-III'; Fig. 13 shows that a pad is configured as a layer different from an electrode; Fig. 14 shows that a pad also has a slot; Fig. 15 and Fig. 16 show that the size of a pad varies depending on its position; Fig. 17 shows an electrode with an interruption section; Fig. 18 shows that the width of the interruption section varies depending on the position; Fig. 19 shows an interrupted section with a web; Fig. 20 is a cross section along the Fig. 19 shown line IV-IV'; Fig. 21 shows a connecting electrode for electrically connecting a pad; Fig. 22 is a cross-sectional view along the Fig. 21 shown line V-V'; Fig. 23 is a flowchart showing a method of manufacturing a solar cell module according to an embodiment of the invention; Fig. 24 shows a dispersion layer disposed between a conductive layer and an insulating layer; Fig. 25 is a cross-sectional view along the Fig. 24 shown line VI-VI'; Fig. 26 shows a dispersion layer formed in an electrode having an interrupted portion; Fig. 27 is a cross-sectional view along the Fig. 26 shown line VII-VII'; Fig. 28 shows an example in which a dispersion layer is formed in plurality; Fig. 29 is a perspective view of a solar cell module comprising solar cells of conventional structure; Fig. 30 is a cross-sectional view taken along the Fig. 29 shown line AA; Fig. 31 is a cross-sectional view along the Fig. 29 shown line BB; Fig. 32 shows a wiring element; Fig. 33 shows a first example of a first electrode; Fig. 34 shows a second example of a first electrode; Fig. 35 shows a third example of a first electrode; Fig. 36 shows a fourth example of a first electrode; Fig. 37 shows a fifth example of a first electrode; Fig. 38 shows a sixth example of a first electrode; Fig. 39 shows a seventh example of a first electrode; Fig. 40 shows that a first electrode includes an extension pad and an auxiliary pad; Fig. 41 shows that a second electrode includes an extension pad and an auxiliary pad; Fig. 42 shows that a solar cell module comprising solar cells of conventional structure includes a reflector; Fig. 43 is a cross-sectional view along the Fig. 42 shown line AA; Fig. 44 is a cross-sectional view taken along the Fig. 42 shown line BB; Fig. 45 shows a wiring element of a Fig. 42 solar cell module shown; Fig. 46 shows a first electrode of a Fig. 42 solar cell module shown; Fig. 47 shows a second electrode of a Fig. 42 solar cell module shown; Fig. 48 to 51 show a positional relationship between a front pad and a rear pad; Fig. 52 shows a reflector of a Fig. 42 solar cell module shown; Fig. 53 is a cross-sectional view taken along the Fig. 52 shown line CC; and Fig. 54 to 58 show different structures of a reflector along the Fig. Line CC shown in Figure 52. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. The invention may, however, be embodied in many different forms and is not to be construed as limited to the embodiments illustrated herein. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. Care is taken to omit a detailed description of the prior art where it is determined that a detailed description of the prior art might misunderstand embodiments of the invention.

[0035] Fig. 1 shows an overall shape of a solar cell module according to an embodiment of the invention. In particular, Fig. 1 the solar cell module with three adjacent solar cells connected horizontally.

[0036] As in Fig. As shown in Figure 1, each of the solar cells 10a to 10c has a regular hexahedral shape with a thin thickness. Each solar cell includes first conductive electrodes (hereinafter referred to as "first electrodes") 11 and second conductive electrodes (hereinafter referred to as "second electrodes") 13 formed on a rear surface of the solar cell and collecting electrons and holes separately.

[0037] The first and second electrodes 11 and 13 are alternately arranged on a rear surface of a semiconductor substrate 15 parallel to each other in a first direction. As shown in Fig. For example, as shown in Figure 1, the first electrodes 11 extend vertically and are arranged parallel to each other, and the second electrodes 13 extend vertically and are arranged parallel to each other. The first and second electrodes 11 and 13 are arranged alternately horizontally and are separated by a uniform distance.

[0038] The first electrode 11 and the second electrode 13 are electrically connected to a wiring element 25 and thus connected to the second electrode 13 and the first electrode 11 of another solar cell adjacent to the solar cell.

[0039] The wiring member 25 is arranged in the horizontal direction (e.g., the second direction) that crosses the vertical direction (e.g., the first direction) of the first and second electrodes 11 and 13, and electrically connects the two adjacent solar cells to each other, thereby connecting the plurality of solar cells 10a to 10c in series. The solar cells 10a to 10c can be connected in series or in parallel. In the following description, the solar cell module in which the solar cells 10a to 10c are connected in series will be described as an example.

[0040] The wiring element 25 includes a first wiring element 21 and a second wiring element 23. The configuration will be described using the second solar cell 10b located in the center as an example. Namely, the first wiring element 21 is electrically connected to the first electrodes 11 and insulated from the second electrodes 13, and the second wiring element 23 is electrically connected to the second electrodes 13 and insulated from the first electrodes 11.

[0041] Specifically, one side of the first wiring member 21 is electrically connected to the first electrodes 11 of the second solar cell 10b, and the other side is electrically connected to the second electrodes 13 of the third solar cell 10c adjacent to the second solar cell 10b, thereby connecting the second solar cell 10b to the third solar cell 10c. Further, one side of the second wiring member 23 is electrically connected to the second electrodes 13 of the second solar cell 10b, and the other side is electrically connected to the first electrodes 11 of the first solar cell 10a adjacent to the second solar cell 10b, thereby connecting the second solar cell 10b to the first solar cell 10a.

[0042] The first wiring elements 21 and the second wiring elements 23 are arranged alternately in the vertical direction and parallel to each other.

[0043] Since the wiring elements 25 are arranged in a direction crossing the electrodes 11 and 13 as described above, it is easy to connect the wiring elements 25 to the electrodes 11 and 13, and the alignment between the wiring elements 25 and the electrodes 11 and 13 also becomes easy. In the embodiment of the invention, the first and second electrodes 11 and 13 are formed parallel to each other on the rear surface of the solar cell, and the wiring elements 25 are connected to the first and second electrodes 11 and 13 in the direction crossing the first and second electrodes 11 and 13. Therefore, a thermal deformation direction of the wiring elements 25 and a thermal deformation direction of the first and second electrodes 11 and 13 cross each other. This can protect the solar cell from latent stress resulting from thermal deformation.

[0044] Fig. 2 is a cross-sectional view schematically showing the Fig. 1 shows the solar cell. As shown in Fig. 2, the solar cell according to the invention is a back contact solar cell in which all the first and second electrodes 11 and 13 are arranged on the back surface of the semiconductor substrate 15 of a first conductivity type (e.g., a p-type or an n-type).

[0045] Thin layers 16 and 17 are applied to a front surface (on which light is incident) and the rear surface (opposite the front surface) of the semiconductor substrate 15, which prevent the reflection of light and fulfill a passivation function.

[0046] A thin emitter region 18 and a thin backfield region 19 are formed between the first electrode 11 and the semiconductor substrate 15 and between the second electrode 13 and the semiconductor substrate 15, respectively, each of which can reduce a potential barrier and facilitate the collection of charge carriers by the electrodes 11 and 13.

[0047] The solar cell has a square planar shape of 180 mm or less by 180 mm or less, and the thickness of the solar cell is equal to or less than 250 µm. This means that the solar cell has a very thin plate shape. Therefore, the solar cell with the thin plate shape may be susceptible to thermal deformation. In particular, the solar cell may exhibit latent stress resulting from thermal deformation because the first and second electrodes 11 and 13 have a different thermal expansion coefficient than the semiconductor substrate 15. Therefore, the solar cell may be physically broken or deformed.

[0048] However, the embodiment of the invention increases a width Wd of each of the first and second electrodes 11 and 13 and reduces a thickness td of each of the first and second electrodes 11 and 13 compared to the prior art, thereby solving the problem resulting from thermal deformation. According to an experiment, when the width Wd of the electrode was 100 µm to 600 µm and the thickness td of the electrode was 0.1 µm to 10.0 µm, carriers could be stably collected, and the above-described problems could be solved.

[0049] Fig. 3 shows an entire wiring element of the Fig. 1 solar cell module, and Fig. 4 is a cross-sectional view of the Fig. 3 shown wiring element. As shown in Fig. 3 and Fig. As shown in Figure 4, the wiring element 25 has a rectangular strip shape with a thin thickness and a rectangular cross-section. Furthermore, the wiring element 25 has a width Sd of 1.0 mm to 50 mm and a thickness Ad of 25 µm to 200 µm.

[0050] Since the wiring member 25 is connected to the electrodes 11 and 13, the thermal deformation of the wiring member 25 can be transmitted to the solar cells 10a to 10c when the wiring member 25 is thermally deformed. Consequently, the solar cells 10a to 10c can be deformed. However, in the embodiment of the present invention, the thermal deformation can be minimized by reducing the thickness Ad of the wiring member 25, and the transfer of carriers can also be smoothly performed by increasing the width Sd of the wiring member 25.

[0051] As in Fig. As shown in Figure 4, the wiring element 25 includes a cladding layer 251 forming the surface and a core layer 253 coated with the cladding layer 251 in a thin layer thickness, e.g., 15 µm to 35 µm. The core layer 253 may be formed of a metallic material with good conductivity, e.g., Ni, Cu, Ag, and Al. The cladding layer 251 may be made of Pb, Sn, or a solder having the chemical formula SnIn, SnBi, SnPb, SnCuAg, and SnCu, or a combination thereof.

[0052] Fig. 5 shows another wiring element according to the embodiment of the invention, and Fig. 6 is a cross-sectional view of the Fig. 5 shown wiring element. As shown in Fig. 5 and Fig. As shown in Figure 6, a wiring element 25 is in the form of a wire with a circular cross-section. The wiring element 25 includes a sheath layer 351 and a core layer 353 and has a diameter of 250 µm to 500 µm. As described above, thermal deformation due to the circular cross-section of the wiring element 25 can be reduced compared to the wiring element 25 shown in Figure 6. Fig. 3 further remove the wiring element 25 shown.

[0053] Fig. 3 and Fig. 5 show the rectangular wiring element and the circular wiring element as examples. However, the embodiment of the invention is not limited to this. For example, the wiring element may have a polygonal or curved shape.

[0054] The wiring member 25 having the configuration described above may further include a buffer. Fig. 7 shows an example where a buffer is placed on the Fig. 3 shown band-shaped wiring element.

[0055] As in Fig. As shown in Figure 7, a buffer 25a is configured so that the wiring member 25 can stretch in a longitudinal direction. The buffer 25a is configured so that the actual length of the buffer 25a is greater than the width Bwd of the buffer 25a, and therefore can have any shape as long as it can stretch. For example, the buffer 25a can have a twisted shape like a coil or a pleated shape with peaks and valleys. Fig. 7 shows as an example the buffer 25a in pleated form, in which the actual length of the buffer 25a is greater than the width Bwd of the buffer 25a.

[0056] In addition, the width Bwd of the buffer 25a must be equal to or smaller than the distance between the solar cells. As shown in Fig. 1, the majority of solar cells are arranged at a regular pitch fd and connected to each other by the wiring elements 25. The buffer 25a is provided between the solar cells. Even if the pitch between the solar cells connected by the wiring elements 25 increases, the buffer 25a can expand in accordance with the increased pitch. In this way, the wiring element 25 can be prevented from breaking due to stress applied to the wiring element 25, and the solar cell module can be protected from physical impact such as damage to a portion of the connection between the wiring element 25 and the first and second electrodes 11 and 13. Therefore, the width Bwd of the buffer 25a must be equal to or smaller than the pitch fd between the solar cells.

[0057] The following describes an electrical connection relationship between the electrodes of each solar cell and the wiring elements with reference to the Fig. 8 to 10 described.

[0058] Fig. Fig. 8 shows a connection relationship between the electrodes of each solar cell and the wiring elements in the Fig. 1 solar cell module shown. Fig. 9 is a cross-sectional view taken along the Fig. Line I-I' shown in Figure 8. Fig. 10 is a cross-sectional view taken along line II-II' shown in FIG: 8.

[0059] As in the Fig. As shown in Figures 8 to 10, in each of the solar cells 10a to 10c, the first electrodes 11 extend parallel to each other, and the second electrodes 13 extend parallel to each other. Furthermore, the first and second electrodes 11 and 13 are arranged alternately in the vertical direction (e.g., in the y-axis direction in the drawings).

[0060] In the same way as the first and second electrodes 11 and 13, the first wiring elements 21 extend parallel to each other, and the second wiring elements 23 extend parallel to each other. Furthermore, the first and second wiring elements 21 and 23 are arranged alternately in the horizontal direction (e.g., in the x-axis direction in the drawings).

[0061] As described above, in each of the solar cells 10a to 10c, the first and second electrodes 11 and 13 and the first and second wiring elements 21 and 23 are alternately arranged. The first electrode 11 and the second electrode 13 each collect carriers of a first conductivity type and carriers of a second conductivity type opposite to the first conductivity type, and the first and second wiring elements 21 and 23 transfer carriers of different conductivity types. In the embodiment of the invention, since the electrodes and wiring elements each have the alternate arrangement structure, each solar cell can uniformly collect and transfer carriers throughout the solar cell.

[0062] The first wiring elements 21 are arranged on the second solar cell 10b and the third solar cell 10c and electrically connect the second solar cell 10b to the third solar cell 10c. The second wiring elements 23 are arranged on the first solar cell 10a and the second solar cell 10b and electrically connect the first solar cell 10a to the second solar cell 10b.

[0063] In each of the solar cells 10a to 10c, a conductive layer 41 and an insulating layer 43 are disposed between the first and second wiring members 21 and 23 and between the first and second electrodes 11 and 13, thereby selectively connecting the wiring member and the electrode or selectively separating the wiring members and the electrodes.

[0064] The conductive layer 41 is designed such that conductive particles are encased in an epoxy-based or silicon-based resin. In this way, the conductive layer 41 has the necessary adhesion and conductivity. The conductive particles can be made of Ni, Al, Ag, Cu, Pb, Sn, or a metal material with the chemical formula SnIn, SnBi, SnPb, SnCuAg, SnCu, or a compound containing at least two of the above materials. The conductive layer 41 can be made of a tin (Sn) alloy that does not contain a synthetic resin, for example, a tin (Sn) alloy with the chemical formula SnIn, SnBi, SnPb, SnCuAg, and SnCu.

[0065] The conductive layer 41 may consist of a solder paste. The solder paste is a paste containing Pb- or Sn-containing solder particles and bonds two materials together by melting the solder particles present in the solder paste when the solder paste is exposed to heat equal to or higher than the melting temperature.

[0066] The conductive layer 41 thus formed electrically connects the first wiring element 21 or the second wiring element 23 and the first electrode 11 or the second electrode 13.

[0067] The insulating layer 43 is made of an adhesive insulating material, such as an epoxy-based resin, a silicon-based resin, or ceramic. The insulating layer 43 prevents electrical connection between the first wiring element 21 and the first electrode 11 or the 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 element 21 and the first electrode 11 cross, and in a second region A2 where the second wiring element 23 and the second electrode 13 cross, thereby 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 element 21 and the second electrode 13 cross, and in a fourth region A4 where the second wiring element 23 and the first electrode 11 cross, thereby electrically isolating them from each other.

[0070] The first wiring element 21 is thus electrically connected to the first electrode 11 of the second solar cell 10b and insulated from the second electrode 13 of the second solar cell 10b.

[0071] In the third solar cell 10c, the conductive layer 41 is located in a fifth region A5 where the first wiring element 21 and the second electrode 13 intersect, and the insulating layer 43 is located in a sixth region A6 where the first wiring element 21 and the first electrode 11 intersect. Thus, the first wiring element 21 is electrically connected to the second electrode 13 of the third solar cell 10c and insulated from the first electrode 11 of the third solar cell 10c.

[0072] As a result, the first wiring member 21 is electrically connected to the first electrode 11 of the second solar cell 10b and the second electrode 13 of the third solar cell 10c, thereby electrically connecting the second solar cell 10b to the third solar cell 10c (see Fig. 9).

[0073] In the first solar cell 10a, the conductive layer 41 is located in a seventh region A7 where the second wiring element 23 and the first electrode 11 intersect, and the insulating layer 43 is located in an eighth region A8 where the second wiring element 23 and the second electrode 13 intersect. Thus, the second wiring element 23 is electrically connected to the first electrode 11 of the first solar cell 10a and insulated from the second electrode 13 of the first solar cell 10a.

[0074] Thereby, the second wiring element 23 is electrically connected to the second electrode 13 of the second solar cell 10b and the first electrode 11 of the first solar cell 10a, whereby the second solar cell 10b is electrically connected to the first solar cell 10a (see Fig. 10).

[0075] As described above, in a solar cell, at least one first wiring element 21 and at least one second wiring element 23 are required as wiring elements connected to or insulated from the electrode via the conductive layer 41 and the insulating layer 43. Up to 20 first wiring elements 21 and up to 20 second wiring elements 23 are required in a solar cell. However, the number of wiring elements can be adjusted accordingly depending on the size of the solar cell, the size of the electrode, the size of the wiring element, etc.

[0076] The first wiring elements 21 and the second wiring elements 23 connect two solar cells (e.g., the first and third solar cells 10a and 10c) adjacent to one solar cell (e.g., the second solar cell 10b) to the one solar cell. Therefore, the ends of the first wiring elements 21 are gathered at a left edge of the second solar cell 10b, and the ends of the second wiring elements 23 are gathered at a right edge of the second solar cell 10b. The number of first and second wiring elements 21 and 23 in one solar cell is each half of the total number of wiring elements 25.

[0077] Fig. Fig. 11 shows that a pad 14 is formed at the intersections of the electrodes 11 and 13 and the wiring element 25, and Fig. 12 is a cross-sectional view along the Fig. 11. In the following description, the embodiment of the invention will be described using the second solar cell 10b as an example.

[0078] As described above, the conductive layer 41 is located in an electrical connection portion of the electrodes 11 and 13 and the wiring member 25, whereby the first wiring member 21 is electrically connected to the first electrode 11 and the second wiring member 23 is electrically connected to the second electrode 13.

[0079] In addition, the insulating layer 43 is located in a non-connecting portion between the electrodes 11 and 13 and the wiring member 25, thereby isolating the first wiring member 21 from the second electrode 13 and the second wiring member 23 from the first electrode 11.

[0080] The pad 14 is formed in the connecting portion between the electrodes 11 and 13 and the wiring member 25 in each solar cell, and includes first pads 141 and second pads 143. The first pads 141 are formed in a portion (i.e., an electrical connecting portion) of the first electrode 11 between the intersections of the first wiring members 21 and the first electrodes 11, and the second pads 143 are formed in a portion (i.e., an electrical connecting portion) of the second electrode 13 between the intersections of the second wiring members 23 and the second electrodes 13.

[0081] The pad 14 helps in the electrical connection of the first and second electrodes 11 and 13 to the wiring member 25 via the conductive layer 41. In addition, the pad 14 increases the intersection area between the electrodes 11 and 13 and the wiring member 25 when the charge carriers collected by the electrodes 11 and 13 are transferred to the wiring member 25 and reduces the surface resistance, thereby reducing the loss of charge carriers.

[0082] The embodiment of the invention describes that the pad 14 is formed of the same material as the electrodes 11 and 13 and is configured as a part of the electrodes 11 and 13, but is not limited thereto. For example, as shown in Fig. 13, the pad 14 may be formed of a different conductive material than the electrodes 11 and 13, or the conductive layer 41 may be configured as the pad 14.

[0083] A horizontal width Pwa of the pad 14 is smaller than a distance Gwa between the first and second electrodes 11 and 13 and larger than a width Gw of the first and second electrodes 11 and 13. Further, a vertical width Pwb of the pad 14 is smaller than a distance Wb between the first and second wiring elements 21 and 23 and larger than a width Bw of each of the first and second wiring elements 21 and 23.

[0084] When the horizontal width Pwa of the pad 14 is greater than the distance Gwa between the first and second electrodes 11 and 13, the adjacent electrodes may contact each other because of the pad 14. This may cause a short circuit between the adjacent electrodes. When the horizontal width Pwa of the pad 14 is greater than the width Gw of the electrode, the pad 14 can be stably configured. When the vertical width Pwb of the pad 14 is greater than the distance Wb between the first and second wiring elements 21 and 23, the adjacent pads may contact each other. This may cause a short circuit between the adjacent electrodes. When the vertical width Pwb of the pad 14 is greater than the width Bw of the wiring element, the wiring element can be stably connected to the electrode.

[0085] Fig. Figure 13 shows that a pad 14' is formed as a layer different from the electrode. Fig. Pad 14' shown in Figure 13 is formed on the electrode and configured as a layer different from the electrode, in contrast to pad 14 described above.

[0086] The Fig. The pad 14' shown in Figure 13 can be manufactured by a screen printing process, an inkjet process, a dispensing process, etc., and has a thickness of 1 µm to 20 µm. The pad 14' can be made of Ni, Al, Ag, Cu, Pb, Sn, or a metal material with the chemical formula SnIn, SnBi, SnPb, SnCuAg, SnCu, or a compound of at least two of the above-mentioned materials. The pad 14' can, for example, be made of the same material as the conductive layer 41.

[0087] Since the pad 14' in the embodiment according to the invention is arranged between the electrodes 11 and 13 and the conductive layer 41 or between the electrodes 11 and 13 and the insulating layer 43, the design freedom can be increased.

[0088] Indeed, if the pad 14' is not formed or configured as part of the electrode, the material of the conductive layer 41 or the insulating layer 43 can only be selected based on the electrode. However, since the electrodes have already been formed on the substrate, it is difficult to change the material of the electrodes.

[0089] In contrast, if the pad 14' is configured as the layer different from the electrode, as in Fig. As shown in Figure 13, the material forming the conductive layer 41 or the insulating layer 43 can be selected based on the pad 14'. Since the pad 14', unlike the electrode, is not formed on the substrate, the material forming the pad 14' can vary if necessary or desired. As a result, the range of material forming the conductive layer 41 or the insulating layer 43 can be wider.

[0090] For example, if the electrodes 11 and 13 are formed of Ni, it is difficult to use the solder made of tin (Sn) or Sn alloy as the material for the conductive layer if there is no pad 14'. However, if the pad 14' is made of Cu, Ag, or Au, the solder made of tin (Sn) or Sn alloy can be used as the material for the conductive layer.

[0091] Fig. 14 shows that the pad also has a slot. As in Fig. As shown in Figure 14, at least one of the first and second pads 14 may have slots 145, each having a thin groove. The slot 145 is formed along the longitudinal direction of the wiring element and is located in a majority left-right symmetrical manner around a center line of the wiring element. Therefore, the slots 145 of the pad 14 may be formed as shown in (A) of Figure 14. Fig. 14, be completely comb-shaped.

[0092] In Fig. 14 shows (A) that the slots 141 are formed along the longitudinal direction of the wiring member; (B) shows that the slots 141 are formed along an oblique direction of the wiring member; (C) shows that the slots 141 are formed in a diamond shape; and (D) shows that the slots 141 are formed in a lattice shape. Alternatively, the slots 141 may also be formed without a regular pattern.

[0093] If the pad 14 also has a slit, the amount of the conductive layer 41 to be deposited can be increased when the conductive layer 41 is formed on the pad 14. Consequently, the connection strength and conductivity can be increased. Even if the size of the electrode increases due to the pad 14, recombination and / or disappearance of charge carriers at the pad 14 can be prevented because the actual cross-sectional area of ​​the electrode does not increase.

[0094] The Fig. 15 and Fig. 16 show that the size of the pad 14 varies depending on the position. In particular, Fig. 15, that all pads of one row in the longitudinal direction of the wiring element 25 are larger than all pads of another row. Fig. 16 shows that only one of the pads in each row is larger than the remaining pads in each row. In the embodiment of the invention, at least one of the pads 14 may have a different size than the remaining pads 14. In particular, the first pad 141 or the second pad 142 may include a first contact pad 14a with a width greater than the width of each of the first and second electrodes 11 and 13 and a second contact pad 14b larger than the first contact pad 14a.

[0095] The size of the pad 14 includes a case where a two-dimensional area differs from a three-dimensional volume. Fig. 15, which is the top view of the electrode, shows various connection areas in which the wiring element 25 is electrically connected to the pad 14 via the conductive layer 41.

[0096] In Fig. 15, an area of ​​the second contact pad 14b is larger than an area of ​​the first contact pad 14a. A simple method for increasing the area is to increase the horizontal width Pca or the vertical width (or length) Pcb of the second contact pad 14b more than the horizontal width or vertical width of the first contact pad 14a. Fig. 15 shows, as an example, that both the horizontal width Pca and the vertical width Pcb of the second contact pad 14b are larger than the horizontal width and the vertical width of the first contact pad 14a.

[0097] Since the solar cell must be fully exposed to a high temperature to connect the electrodes 11 and 13 to the pad 14, the solar cell may be bent in a process for connecting the electrodes 11 and 13 and the pad 14. However, in the embodiment of the invention, since the size of the second contact pad 14b is larger than the size of the first contact pad 14a, the wiring member 25 is first attached to the second contact pad 14b. After a predetermined period of time has elapsed, the wiring member 25 is attached to the first contact pad 14a. Since the solar cell is exposed to a high temperature during the predetermined period of time, the deflection of the substrate can be reduced. The second contact pad 14b can also improve the physical bonding strength and contact resistance between the wiring member 25 and the first and second electrodes 11 and 13.

[0098] In one manufacturing method, the wiring element 25 is fixed by a thermal process in a state where the wiring element 25 is disposed on a liquid conductive layer. However, since the conductive layer is a liquid layer, the wiring element 25 may be bent during the thermal process. Since the wiring element 25 is first fixed to the second contact pad 14b in the embodiment of the present invention and can then be fixed to the first contact pad 14a by the thermal process, the bending of the wiring element 25 can be prevented.

[0099] In the embodiment of the invention, the wiring member 25 is heated to a temperature lower than the curing temperature at which the conductive layer or the insulating layer can be cured, and temporarily attached to the second contact pad 14b. Subsequently, the wiring member 25 is heated to a temperature equal to or higher than the curing temperature and connected to the electrode. Therefore, it is preferable, but not mandatory, that the number of temporarily attached second contact pads 14b be fewer than the number of first contact pads 14a.

[0100] Fig. 17 shows that each of the electrodes 11 and 13 also has an interruption portion.

[0101] As in Fig. 17, at least a portion of the second electrodes 13 insulated from the first wiring member 21 or at least a portion of the first electrodes 11 insulated from the second wiring member 23 in the solar cell module according to the embodiment of the invention may have a cut-off portion 111 in which the electrode is not present (or missing) by partially cutting off (or not forming) the electrode.

[0102] In the embodiment of the invention, the interrupted portion 111 is a portion where the electrode is cut off and absent. Each of the electrodes 11 and 13 is cut off by a predetermined width Cw in its longitudinal direction. Thus, each of the electrodes 11 and 13 is absent by the predetermined width Cw.

[0103] The interruption portion 111 is formed along non-connection portions and includes a first interruption portion 111a and a second interruption portion 111b. The first interruption portion 111a is formed in the non-connection portions of the first electrode 11, and the second interruption portion 111b is formed in the non-connection portions of the second electrode 13. The first interruption portion 111a and the second interruption portion 111b are arranged alternately and are not aligned.

[0104] The interruption section 111 prevents physical contact between the electrodes 11 and 13 and the wiring element 25 in the non-connection sections, thus blocking any electrical connection between them. The width Cw of the interruption section 111 must be greater than the width Bw of the wiring element 25.

[0105] Since the interruption portion 111 is formed in the non-connection portion between the electrodes 11 and 13 and the wiring member 25, the interruption portion 111 does not affect the efficiency of the solar cell even if the electrode has the interruption portion 111.

[0106] As described above, since the electrodes 11 and 13 are not physically connected to the wiring element 25 in the non-connection portions, the insulating layer 43 does not need to be formed in the non-connection portions when each of the electrodes 11 and 13 includes the interruption portion 111. Therefore, the manufacturing yield can be increased and the manufacturing cost can be reduced.

[0107] Fig. 17 shows that all of the second electrodes 13 insulated from the first wiring elements 21 and the first electrodes 11 insulated from the second wiring elements 23 have the interruption portion 111. However, only a portion of the second electrodes 13 insulated from the first wiring elements 21 and only a portion of the first electrodes 11 insulated from the second wiring elements 23 may have the interruption portion 111. The insulating layer 43 may be formed in the remaining portion of the first and second electrodes 11 and 13. Therefore, the first wiring elements 21 and the second electrodes 13 may be insulated by the insulating layer 43, and the second wiring elements 23 and the first electrodes 11 may be insulated by the insulating layer 43.

[0108] Fig. 18 shows that the width of the interruption section varies depending on the position.

[0109] In Fig. 18, it is assumed that the electrodes 11 and 13 belonging to a first group G1 denote the electrodes arranged in the longitudinal direction of the wiring element 25 adjacent to a left side LL of the solar cell; the electrodes 11 and 13 belonging to a second group G2 denote the electrodes arranged in the longitudinal direction of the wiring element 25 adjacent to a right side RL of the solar cell; and the electrodes 11 and 13 belonging to a third group G3 denote the electrodes arranged between the first group G1 and the second group G2, that is, in the center of the solar cell.

[0110] In the embodiment of the invention, the interruption section 111 includes a first long interruption section 113 formed on the electrodes 11 and 13 belonging to the first group G1, a second long interruption section 115 formed on the electrodes 11 and 13 belonging to the second group G2, and a short interruption section 117 formed on the electrodes 11 and 13 belonging to the third group G3.

[0111] The first long interruption section 113 separates the electrodes from each other by a first distance Da1 in the longitudinal direction of the electrode; the second long interruption section 115 separates the electrodes from each other by a second distance Da2 in the longitudinal direction of the electrode; and the short interruption section 117 separates the electrodes from each other by a third distance Da3 in the longitudinal direction of the electrode. It is preferable, but not required, that the first distance Da1 and the second distance Da2 be equal and greater than the third distance Da3. Furthermore, it is preferable, but not required, that the third distance Da3 be greater than the width of the wiring element 25 and the first distance Da1 and the second distance Da2 be smaller than the distance between the first and second wiring elements 21 and 23.

[0112] As described above, the disconnection portion 111 includes the first long disconnection portion 113, the second long disconnection portion 115, and the short disconnection portion 117, each of which has a different interelectrode pitch depending on the position. Therefore, when the wiring member 25 is attached to the solar cells 10a to 10c, a short circuit resulting from the bending of the wiring member 25 and contact between the wiring member 25 and the electrode in the non-connection portion can be prevented due to a clearance corresponding to a difference between the first pitch Da1 and the third pitch Da3.

[0113] Fig. 19 shows the interruption section enclosing (or contacting) a web, and Fig. 20 is a cross-sectional view taken along the Fig. 19. In the embodiment of the invention, a ridge 51 corresponds to an insulating material that selectively covers one end of the electrodes 11 and 13, including the interruption portion 111 (or is arranged or positioned thereon). The ridge 51 includes a first ridge 51a and a second ridge 51b. The first ridge 51a and the second ridge 51b are formed in an island shape on and below the wiring element 25. The first ridge 51a is located on the wiring element 25, and the second ridge 51b is located below the wiring element 25.

[0114] The paired ridge 51 is arranged at one end of the electrode forming the interruption portion 111 and has a cross-sectional shape that overlaps the end of the electrode. Thus, the wiring element 25 is located above the interruption portion 111 between the first ridge 51a and the second ridge 51b. Therefore, the ridge 51 can prevent physical contact between the wiring element 25 and the electrodes 11 and 13 resulting from misalignment.

[0115] A horizontal width Bhw of the web 51 must be greater than a width Gw of the electrodes 11 and 13 and must be smaller than a distance Gwa between the electrodes 11 and 13. Furthermore, a vertical width Bvw of the web 51 must be smaller than a distance Wb between the wiring elements.

[0116] When the horizontal width Bhw of the ridge 51 is larger than the width Gw of the electrodes 11 and 13, the ridge 51 overlaps the electrodes 11 and 13 in the horizontal direction. Therefore, the ridge 51 can prevent physical contact between the wiring member 25 and the electrodes 11 and 13. When the horizontal width Bhw of the ridge 51 is larger than the distance Gwa between the electrodes 11 and 13, the ridge 51 can be formed on the pad 14 adjacent to the interruption portion 111 in the vertical direction. Therefore, the ridge 51 can prevent physical contact between the pad 14 and the wiring member 25 in a portion of the connection.

[0117] The web 51 may be made of the same material as the insulating layer 43 or of a different material than the insulating layer 43. Fig. 19 and Fig. 20 shows, as an example, that the planar shape of the web 51 is a quadrilateral. Other shapes can be used for the web 51. The planar shape of the web 51 can be, for example, a circle or an oval.

[0118] Fig. 21 shows a connecting electrode for electrically connecting the pad 14, and Fig. 22 is a cross-sectional view along the Fig. Line V-V' shown in Figure 21.

[0119] In the embodiment of the invention, the first electrode 11 includes the first pad 141 and the first interruption portion 111a, and the second electrode 13 includes the second pad 143 and the second interruption portion 111b.

[0120] In the embodiment of the invention, a connecting electrode 61 extends in the horizontal direction (for example, in the y-axis direction in the drawing) and overlaps the wiring member 25. The connecting electrode 61 can be formed together with the electrodes 11 and 13 in the same process as the electrodes 11 and 13, or separately in a different process than the electrodes 11 and 13. When the connecting electrode 61 is manufactured in the same process as the electrodes 11 and 13, the connecting electrode 61 and the electrodes 11 and 13 can be made of the same material, so the number of manufacturing processes can be reduced. When the connecting electrode 61 and the electrodes 11 and 13 are manufactured in different processes, the connecting electrode 61 and the electrodes 11 and 13 can be made of different materials.Therefore, the choice of materials for the connecting electrode 61 and the electrodes 11 and 13 can be expanded.

[0121] In other words, if the connecting electrode 61 and the electrodes 11 and 13 are manufactured using the same process, the connecting electrode 61 and the electrodes 11 and 13 may be made of the same material. If the connecting electrode 61 and the electrodes 11 and 13 are manufactured using different processes, the connecting electrode 61 and the electrodes 11 and 13 may be made of different materials.

[0122] The connection electrode 61 includes a first connection electrode 61a and a second connection electrode 61b. The first connection electrode 61a is physically and electrically connected to the first pad 141 of the first electrode 11, which is adjacent to the second interruption portion 111b, via the second interruption portion 111b provided in the second electrode 13. The second connection electrode 61b, in the same manner as the first connection electrode 61a, is physically and electrically connected to the second pad 143 of the second electrode 13, which is adjacent to the first interruption portion 111a, via the first interruption portion 111a provided in the first electrode 11.

[0123] The first connection electrode 61a and the second connection electrode 61b are separated from each other by a predetermined distance Cdd and arranged parallel to each other. The distance Cdd between the first connection electrode 61a and the second connection electrode 61b is substantially the same as a distance Wb between the first wiring element 21 and the second wiring element 23.

[0124] Since the wiring element 25 is arranged on the connection electrode 61, it is preferable, but not mandatory, that a width Cwd of the connection electrode 61 is equal to or larger than a width Bw of the wiring element 25 and smaller than the vertical width of the pad 14.

[0125] The second wiring element 23 is located on the first connection electrode 61a and the first wiring element 21 is located on the second connection electrode 61b.

[0126] The conductive layer 41 is located between the connecting electrode 61 and the wiring element 25 and enables easy connection between the connecting electrode 61 and the wiring element 25. The conductive layer 41 can optionally be omitted. In this case, the wiring element 25 is soldered directly to the connecting electrode 61. Alternatively, a solder paste can also connect the wiring element 25 to the connecting electrode 61.

[0127] A method of manufacturing the solar cell module according to the embodiment of the invention will be described below with reference to Fig. 23 described.

[0128] In step S11, an insulating adhesive is applied to each non-connection portion to form an insulating layer. The insulating adhesive is a mixture of a curing agent containing a high-viscosity liquid epoxy- or silicon-based resin as the main component, a filler, a reinforcing agent, etc. The insulating adhesive can be applied to the non-connection portion by a known method, such as a screen printing method, an inkjet method, and a dispensing method.

[0129] The insulating adhesive may be applied to the non-connection portion in the form of an island so that the wiring member 25 is not connected to either of the first electrode 11 and the second electrode 13, as in the case shown in Fig. 8 shown patterns.

[0130] The curing temperature of the insulating adhesive varies depending on the material of the insulating adhesive. The melting temperature required to melt the insulating adhesive after curing the insulating adhesive must be higher than the curing temperatures of a conductive adhesive and the wiring element 25. Preferably, but not necessarily, the curing temperature of the insulating adhesive is higher than 210°C and lower than 250°C, and the melting temperature of the insulating adhesive is equal to or higher than 400°C.

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

[0132] Step S11 may be omitted depending on the configuration of the solar cell module. Since the solar cell module in which the electrodes 11 and 13 have the interruption portion does not require the insulating layer 43, step S11 may be omitted from the method for manufacturing the solar cell module.

[0133] In step S12, a conductive adhesive is applied to each connecting portion to form the conductive layer. The conductive adhesive is a mixture of a curing agent containing a high-viscosity liquid epoxy- or silicon-based resin as its main component, a filler, a reinforcing agent, etc., and also contains conductive particles. The conductive particles may comprise a metal material of Ni, Al, Ag, Cu, Pb, Sn, or a metal material with the chemical formula SnIn, SnBi, SnPb, SnCuAg, SnCu, or a mixture of at least two of these materials. A solder paste may be used as the conductive adhesive. The solder paste is a paste containing solder particles containing lead (Pb) or tin (Sn). When the solder paste is subjected to heat equal to or higher than the melting temperature, the solder paste bonds two materials, melting the solder particles present in the solder paste.

[0134] The conductive adhesive, like the insulating adhesive, can be applied to the connecting portion by a known method such as screen printing method, inkjet method and dispensing method.

[0135] The conductive adhesive may be applied to the connecting portion in the form of an island so that the wiring member 25 is connected to one of the first electrode 11 and the second electrode 13, as shown in the Fig. 8 shown patterns.

[0136] The curing temperature of the conductive adhesive varies depending on the material of the conductive adhesive, just as it does for the insulating adhesive. The curing temperature of the conductive adhesive must be lower than the melting temperature of the insulating layer 43. The melting temperature of the conductive adhesive after curing of the conductive adhesive must be higher than the curing temperature of the wiring element 25.

[0137] Preferably, the curing temperature of the conductive adhesive can be substantially the same as the lamination temperature in step S15. When the curing temperature of the conductive adhesive is substantially the same as the lamination temperature in step S15, the conductive adhesive does not need to be cured immediately after application of the conductive adhesive, since the conductive adhesive can be cured in step S15. This can reduce the number of manufacturing processes. Since the solar cell is exposed to the high temperature less frequently, thermal deformation of the solar cell can also be reduced.

[0138] If the curing temperature of the insulating adhesive is substantially the same as the lamination temperature in step S15, the insulating adhesive does not need to be cured in step S11 and can be cured together with the conductive adhesive in step S15. Therefore, the two curing processes (of the insulating adhesive and the conductive adhesive) can be omitted.

[0139] If the curing temperature of the conductive adhesive differs from the lamination temperature in step S15, the conductive adhesive is applied and then exposed to the curing temperature to form the conductive layer.

[0140] Subsequently, the first wiring element 21 and the second wiring element 23 are loaded in step S13. The first wiring element 21 and the second wiring element 23 are arranged in the form of a connection of the two solar cells that are adjacent in the longitudinal direction, as in the example of Fig. 8. The first wiring element 21 and the second wiring element 23 are arranged alternately in the direction crossing the longitudinal direction.

[0141] Then, in step S14, the loaded first and second wiring elements 21 and 23 are fixed with a tape to prevent them from moving. In step S14, the tape may be a liquid tape that applies a liquid material, or a solid tape that applies an adhesive to a film. The liquid tape may be formed by applying the liquid material to the first wiring element 21 and the second wiring element 23 using a dispenser, irradiating the liquid material with ultraviolet (UV) rays, and curing the liquid material. Alternatively, the liquid tape may be formed by applying and curing the liquid material using methods such as screen printing and inkjet printing. For the liquid material, an epoxy-based resin or a silicon-based resin may be used.

[0142] The tape is crossed in a direction that crosses the wiring element 25, allowing the wiring element 25 to be easily fixed. Any type of tape can be used for the tape as long as the tape can fix the wiring element 25. For example, the tape can be attached to the entire back surface of the solar cell on which the wiring element 25 is arranged, and can protect the solar cell from moisture. Alternatively, the tape can be attached so that a portion of the conductive adhesive and the insulating adhesive is exposed when the conductive adhesive or the insulating adhesive is not cured.

[0143] The wiring element 25 may be temporarily fixed at a temperature that is, for example, 90°C to 120°C lower than the curing temperature before the conductive adhesive and / or the insulating adhesive is cured. In this case, step S14 may be omitted.

[0144] In step S15, an encapsulant and a transparent substrate are placed on the thus-fabricated modular solar cell, and an encapsulant and a backsheet are placed under the modular solar cell. In this assembled state, the modular solar cell is thermally pressurized and packaged by a laminator. In this case, the temperature of the thermal process is 145°C to 165°C. Since the electrodes are laminated in a state where all the electrodes are fixed by the tape, it is possible to prevent the electrodes from becoming misaligned during the lamination process.

[0145] The embodiments of the invention in which the solar cell is configured to further include a dispersion layer are described below with reference to the Fig. 24 to 28. Only some of the following embodiments of the invention describe the solar cell including the dispersion layer. However, the configuration of the solar cell with the dispersion layer can be applied in the same or similar manner to the remaining embodiments of the invention.

[0146] Fig. 24 shows a dispersion layer disposed between the conductive layer and the insulating layer, and Fig. 25 is a cross-sectional view along the Fig. Line VI-VI' shown in Figure 24.

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

[0148] The conductive layer 41 and the insulating layer 43 are arranged along the connecting portion and the non-connecting portion, and selectively connect or insulate the wiring elements 25 and the electrodes 11 and 13 at an intersection of the connecting portion and the non-connecting portion.

[0149] A dispersion layer 45 is located horizontally between the conductive layer 41 and the insulating layer 43 and is separated from the conductive layer 41 and the insulating layer 43. The dispersion layer 45 fixes the wiring element 25 to the substrate. It is preferable, but not mandatory, that the dispersion layer 45 be disposed between the conductive layer 41 and the insulating layer 43. However, the dispersion layer 45 can also be selectively formed if necessary or desired.

[0150] Since the dispersion layer 45 is formed at the intersections of the conductive layer 41 and the insulating layer 43 and between the intersections, a horizontal width Sph of the dispersion layer 45 is smaller than a distance Gwa between the first electrode 11 and the second electrode 13. Therefore, the conductive layer 41 or the insulating layer 43 can be normally formed at the intersections.

[0151] In Fig. 24 and Fig. 25 shows the case where a vertical width Spv of the dispersion layer 45 is larger than the width Bw of the wiring element 25. When the vertical width Spv of the dispersion layer 45 is larger than the width Bw of the wiring element 25, the wiring element 25 can be stably attached to the substrate.

[0152] Preferably, the dispersion layer 45 may be made of the same material as the conductive layer 41 or the insulating layer 43. Furthermore, the dispersion layer 45 may be made of the same material as the electrodes 11 and 13.

[0153] Regarding the manufacturing process, it is preferable, but not mandatory, that the dispersion layer 45 be formed together with the conductive layer 41 while the conductive layer 41 is being formed. If the dispersion layer 45 is made of the same material as the conductive layer 41, the dispersion layer 45 can be formed without a new process.

[0154] When the dispersion layer 45 is formed of the same material as the insulating layer 43, the dispersion layer 45 can be formed stably without the risk of a short circuit that may occur when the dispersion layer 45 is formed of a conductive material, because the dispersion layer 45 is arranged between the first electrode 11 and the second electrode 13, which collect carriers of different conductivity types.

[0155] It is preferable, but not mandatory, that the deposition area of ​​each dispersion layer 45 thus formed be larger than the conductive layer 41 or the insulating layer 43. A voltage transmitted from the wiring element 25 is transmitted to the intersections and breaks the physical connection between the electrode and the wiring element. When the deposition area of ​​the dispersion layer 45 is larger than the conductive layer 41 or the insulating layer 43, the voltage transmitted to the dispersion layer 45 is greater than the voltage transmitted to the intersection. Thus, the voltage transmitted to the conductive layer 41 or the insulating layer 43 can be further reduced compared to the prior art.

[0156] Fig. 26 shows the formation of the dispersion layer when the electrode contains the interruption portion, and Fig. 27 is a cross-sectional view along the Fig. Line VII-VII' shown in Figure 26.

[0157] As in the Fig. 26 and Fig. 27, the interruption portion 111 is a portion in which the electrodes 11 and 13 are not present by a predetermined width Cw in the longitudinal direction of the electrodes 11 and 13.

[0158] The interruption portion 111 is formed along non-connection portions and includes a first interruption portion 111a and a second interruption portion 111b. The first interruption portion 111a is formed in the non-connection portions of the first electrode 11, and the second interruption portion 111b is formed in the non-connection portions of the second electrode 13.

[0159] The conductive layer 41 is located along the connecting portions and electrically connects the wiring member to the electrode.

[0160] In the embodiment of the invention, the dispersion layer 45 extends in the longitudinal direction of the wiring member 25 in the non-connection portions in which the interruption portion 111 is formed, and fixes the wiring member 25 to the substrate.

[0161] Since the dispersion layer 45 is formed in the interruption portion 111, the dispersion layer 45 is located between the conductive layers 41 in the longitudinal direction of the wiring element 25. Therefore, the horizontal width Sph of the dispersion layer 45 is smaller than the distance between the first electrodes 11 or the distance between the second electrodes 13, which together with the wiring element 25 form the connection portion. When the vertical width Spv of the dispersion layer 45 is larger than the width of the wiring element 25, the wiring element 25 can be stably attached to the substrate.

[0162] Fig. 28 shows an example in which the dispersion layer is formed in a plurality. In Fig. 28, the dispersion layer 45 is configured to include first to third dispersion layers 45a to 45c. In Fig. Figure 28 shows the case where the first to third dispersion layers 45a to 45c have the same size. The sizes of the first to third dispersion layers 45a to 45c may vary if necessary or desired.

[0163] The following describes a solar cell module with solar cells of a conventional structure, in which the first and second electrodes are formed on both the front and back surfaces of the substrate. There is a structural difference between the solar cells described above and the conventional solar cells. However, the solar cells according to the present invention are similar in that the solar cells contain pads of different sizes. Therefore, the solar cells according to the present invention share technical ideas.

[0164] Fig. 29 is a perspective view of a solar cell module having solar cells of conventional structure. Fig. 30 is a cross-sectional view taken along the Fig. Line AA shown in Figure 29. Fig. 31 is a cross-sectional view along the Fig. Line BB shown in Figure 29. Fig. 32 shows a wiring element.

[0165] As in the Fig. As shown in FIGS. 29 to 32, the solar cell module according to the embodiment of the invention connects a plurality of solar cells arranged adjacent to each other using a plurality of wiring members 125, each having a thin thickness. The wiring member 125 is electrically connected to first electrodes 113 formed on a front surface of a first solar cell C1 of two adjacent solar cells, and is electrically connected to second electrodes 115 formed on a rear surface of a second solar cell C2 adjacent to the first solar cell C1.

[0166] The solar cell is shaped like a cube with a small thickness. The cube-shaped solar cell measures approximately 156 mm long and 156 mm wide and has a thickness of 150 µm to 200 µm.

[0167] The first electrodes 113 are formed on a front surface of a semiconductor substrate 111 onto which light is incident and are connected to the wiring element 125. The first electrodes 113 collect charge carriers of a conductive type opposite to a conductive type of the semiconductor substrate 111. For example, if the semiconductor substrate 111 is a p-type semiconductor substrate, the first electrodes 113 can collect electrons.

[0168] The semiconductor substrate 111 forms a pn junction and is an n- or p-type semiconductor substrate containing impurities of a first conductivity type.

[0169] The second electrodes 115 are formed on a rear surface of the semiconductor substrate 111 in a direction that crosses the first electrodes 113. The second electrodes 115 collect charge carriers of a conductivity type opposite to the conductivity type of the first electrodes 113.

[0170] Between the semiconductor substrate 111 and the first electrodes 113, and between the semiconductor substrate 111 and the second electrodes 115, there are an emitter region and a backfield region, each of which reduces a potential barrier, and a passivation layer that prevents recombination of charge carriers at the surface of the semiconductor substrate 111. However, the above configuration has been omitted from the drawings.

[0171] The two adjacent solar cells, each having the configuration described above, are connected to each other by means of the plurality of wiring elements 125.

[0172] The number of wiring elements 125 can be 6 to 30. As shown in (A) of Fig. 32, the wiring element 125 may be in the form of a wire with a circular cross-section. (B) of Fig. 32 shows the circular cross section of the wiring element 125.

[0173] As in Fig. As shown in Figure 32, the wiring element 125 has a structure in which a cladding layer 125a is deposited on a core layer 125b with a small thickness (e.g., about 12 µm or less). The total thickness of the wiring element 125 is 300 µm to 500 µm.

[0174] The core layer 125b is made of a metal material with good conductivity, such as Ni, Cu, Ag, and Al. The cladding layer 125a is made of Pb, Sn, or a metal material with a chemical formula represented by SnIn, SnBi, SnPb, SnCuAg, and SnCu, and contains a solder. Therefore, the cladding layer 125a can be physically and electrically connected to another metal by soldering.

[0175] When connecting two adjacent solar cells using the wiring element 125, 10 to 15 wiring elements 125 can be used if the semiconductor substrate is 156 mm long and 156 mm wide. The number of wiring elements 125 can vary depending on the size of the semiconductor substrate, the width, the thickness, the pitch of the electrodes, etc.

[0176] So far, in the embodiment of the invention, the wiring element 125 has been described as having a wire shape with a circular cross section. However, the cross section of the wiring element 125 can have various shapes, including a rectangle and an oval.

[0177] The wiring element 125 electrically connects the two adjacent first and second solar cells C1 and C2 by connecting one side of the wiring element 125 to the first electrode 1130 of the first solar cell C1 and the other side of the wiring element 125 to the second electrode 1150 of the second solar cell C2. A preferred method for connecting the electrodes to the wiring element is the soldering method for melting and bonding the material.

[0178] In the embodiment of the invention, at least a portion of the first electrodes 113 may include a plurality of first pads 140 arranged at intersections of the first electrodes 113 and the wiring elements 125 and having a width w1 that is greater than a width of the first electrode 1130.

[0179] The first pad 140 increases the area where the first electrode 1130 and the wiring element 125 intersect, reducing the contact resistance when the first electrode 1130 is connected to the wiring element 125. Furthermore, the first pad 140 increases the strength of the physical connection between the first electrode 1130 and the wiring element 125. In this case, the width of the first electrode 1130 may be increased, or an additional electrode layer may be formed.

[0180] The size of at least one of the first pads 140 may differ from the size of the remaining first pads 140 to further improve the strength of the physical connection and the contact resistance between the wiring elements 125 and the semiconductor substrate 111, while minimizing the bending of the wiring elements 125 and the bending of the semiconductor substrate 111. A size difference between the first pads 140 means that the first pads 140 differ from each other in at least one of the two dimensions: width or length. Thus, the first pads 140 may include at least two pads that differ from each other in at least one of the dimensions: width or length. This is described below.

[0181] The number of first pads 140 may be equal to or greater than 6 and less than the number of first electrodes 113.

[0182] The width w1 of each first pad 140 may be greater than the width of the first electrode 1130 and may be less than 2.5 mm, taking into account a shadowing area in which light is shadowed by the first pad 140, the physical connection strength, and the contact resistance. Furthermore, the length of each first pad 140 may be greater than the width of the first electrode 1130 and less than 30 mm.

[0183] As an example of the soldering method, the wiring elements 125 are arranged on both the front surface and the back surface of each of the two adjacent solar cells, and are arranged opposite the first electrodes 113 and the second electrodes 115 of each of the two adjacent solar cells. In this state, the cladding layers 125a of the wiring elements 125 are heated to a temperature equal to or higher than a melting temperature for several seconds. While the cladding layers 125a are melted and cooled, the wiring elements 125 are fixed to the first and second electrodes 113 and 115.

[0184] In an alternative example, the wiring elements 125 may be attached to the electrodes with a conductive adhesive. The conductive adhesive is a material obtained by adding conductive particles of Ni, Al, Ag, Cu, Pb, Sn, SnIn, SnBi, SnPb, SnCuAg, and SnCu to an epoxy-based resin or a silicon-based resin. The conductive adhesive is a material that hardens when heat is applied to the conductive adhesive in a liquid state. Furthermore, the wiring element 125 may be attached in a solder paste state. The solder paste is a paste containing solder particles containing Pb or Sn, and melts and joins two materials while melting the solder particles present in the solder paste when heat equal to or higher than a melting temperature is applied.

[0185] Various examples of the first electrode are described below with reference to the Fig. 33 to 39 described.

[0186] Fig. 33 shows a first example of a first electrode.

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

[0188] The collecting electrode 1131 has a predetermined width and extends in one direction. The collecting electrodes 1131 are arranged parallel to each other and form a strip-like arrangement. The collecting electrode 1131 has a width of 30 µm to 100 µm and a thickness of 15 µm to 30 µm. The distance P1 between the collecting electrodes 1131 is 1.2 mm to 2.2 mm.

[0189] The connecting electrode 1133 has a predetermined width and extends in a direction that crosses the collecting electrode 1131. The connecting electrodes 1133 electrically and physically connect the collecting electrodes 1131.

[0190] A width of the connecting electrode 1133 is substantially equal to or greater than a width of the collecting electrode 1131 and smaller than a width of the first pad 140. For example, the width of the connecting electrode 1133 may be 75 µm to 120 µm. The thickness of the connecting electrode 1133 may be 15 µm to 30 µm. A distance P2 between the connecting electrodes 1133 may be 5 mm to 23 mm and may be less than ten times the distance P1 between the collecting electrodes 1131.

[0191] Alternatively, the width of the connection electrode 1133 may be greater than the width of the collecting electrode 1131 and equal to or less than the horizontal width w1 of the first pad 140.

[0192] The first pads 140 are selectively formed at the intersections between the collecting electrodes 1131 and the connecting electrodes 1133.

[0193] The first pad 140 is configured so that the electrode and the wiring member 125 can be smoothly connected to each other by increasing an intersection between the electrode and the wiring member 125, in the same manner as in the above-described embodiment. It is preferable, but not required, that the first pads 140 be formed at all intersections of the collecting electrodes 1131 and the connecting electrodes 1133, respectively. However, the first pads 140 may be selectively formed on odd or even rows, or they may be selectively formed according to a predetermined rule. Namely, the first pads 140 may be formed at all intersections or selectively at the intersections.

[0194] The number of the first pads 140 is determined depending on the size, thickness and spacing of the electrodes, etc. Fig. 33 shows that the first pads 140 are formed, for example, selectively at all intersections of six lines each.

[0195] The result of an experiment shows that the solar cell exhibits the best efficiency when the collecting electrode 1131, the connecting electrode 1133, and the first pad 140 are manufactured within the scope of the present disclosure. If the collecting electrode 1131, the connecting electrode 1133, and the first pad 140 are not within the scope of the present disclosure, the solar cell does not exhibit the desired efficiency.

[0196] The collecting electrode 1131, the connecting electrode 1133, and the first pad 140 can be fabricated simultaneously using the screen printing process. In this case, the collecting electrode 1131, the connecting electrode 1133, and the first pad 140 can be made of the same material, e.g., silver (Ag). The components can be fabricated separately if necessary or desired.

[0197] The wiring element 125 is arranged directly on the connecting electrode 1133 and extends in a direction parallel to the connecting electrode 1133. Thus, the wiring element 125 is arranged opposite the connecting electrode 1133. A width Da of the wiring element 125 is 250 µm to 500 µm.

[0198] Since the wiring element 125 is soldered in a state where the wiring element 125 is disposed on the connection electrode 1133, the wiring element 125 is connected to both the connection electrode 1133 and the first pad 140. Therefore, the contact resistance between the electrode and the wiring element can decrease, and the efficiency of the solar cell can increase. The connection strength of the wiring element can increase.

[0199] As in Fig. As shown in Figure 34, which shows a second example of the first electrode, the collecting electrode 1131 may further include an interrupted portion 114. The collecting electrode 1131 does not have a predetermined width Cw of the interrupted portion 114 in an extending direction of the collecting electrode 1131. When the distance between the collecting electrodes 1131 is 10 mm to 14 mm, the width Cw of the interrupted portion 114 may be 1.5 mm to 1.8 mm. Furthermore, the width Cw of the portion 114 may vary between 1.5 mm and 2.2 mm.

[0200] Fig. 34 shows, by way of example, that the interruption section 114 is formed every two rows. However, the second example of the first electrode can be changed. For example, the interruption section 114 can be formed in every row or every third row, or it can be formed randomly. In the second example of the first electrode, the interruption section 114 is formed between the connection electrodes 1133. However, the interruption section 114 can be formed in various locations.

[0201] In the second example of the first electrode, the connecting electrodes 1133 connect the first pads 140, and the wiring member 125 is soldered to the connecting electrode 1133. Therefore, there is no reduction in the efficiency of the solar cell due to the interruption portion 114. Furthermore, since the collecting electrode 1131 includes the interruption portion 114, the manufacturing cost of the solar cell is reduced.

[0202] Fig. 35 shows a third example of the first electrode in which an auxiliary pad is formed between the pads 140.

[0203] As in Fig. 35, in the solar cell module according to the embodiment of the invention, the size of at least one of the plurality of first pads 140 that each solar cell has may be different from the size of the remaining pads.

[0204] As in Fig. For example, as shown in Figure 35, at least one pad may be an auxiliary pad 141 with a relatively small size. The remaining pads may be pads 140 that are relatively larger than the auxiliary pad 141.

[0205] Accordingly, the auxiliary pad 141 has a smaller width or length than the pad 140. The auxiliary pad 141 is formed at an intersection between the first pads 140 in the vertical direction and connects the wiring member 125 and the connection electrodes 1133.

[0206] The auxiliary pad 141 may be made of the same material as the first pad 140. Alternatively, the pad 141 may be made of a conductive adhesive made of a resin with conductive metal particles.

[0207] Preferably, but not necessarily, a horizontal width w2 of the auxiliary pad 141 is equal to or smaller than the width Da of the wiring element 125.

[0208] The size of the auxiliary pad 141 is adjusted in the same way as the first pad 140, taking into account various variables.

[0209] Fig. 35 shows that the auxiliary pad 141 is formed, for example, every two rows between the first pads 140. The auxiliary pad 141 can be formed at various positions. For example, the pad 141 can be formed on every row or at a position corresponding to a multiple of three.

[0210] Fig. Figure 36 shows a different shape of the auxiliary pad as a fourth example for the first electrode. Fig. 35 is essentially the same as the auxiliary pad 141 shown in Fig. 36, except that the auxiliary pad 141' shown in Fig. 35 shown auxiliary pad 141' is formed at the intersection and in Fig. 36, the auxiliary pad 141' connects the collecting electrodes 1131 of two adjacent lines.

[0211] A horizontal width w3 of the auxiliary pad 141' in Fig. 36 is smaller than that of the first pad 140, and a vertical width w4' of the auxiliary pad 141' is larger than that of the first pad 140. This allows a contact area between the wiring member 125 and the first electrode 1130 to be further increased. Consequently, the contact resistance can be reduced and the connection strength can be increased.

[0212] Fig. 37 shows a fifth example of the first electrode.

[0213] In the fifth example of the first electrode, the first electrode 1130 includes a conductor electrode 1135 and a wiring electrode 1137.

[0214] The conductor electrode 1135 consists of a pair of legs 1135a and a connecting piece 1135b that connects the legs 1135a. Thus, the conductor electrodes 1135 form a conductor shape.

[0215] The legs 1135a are separated from each other by a predetermined distance SA and extend in the same direction as an extension direction of the wiring element 125. The distance SA between the legs 1135a is smaller than a distance PD of the wiring element 125 and greater than the width w1 of the first pad 140. Preferably, the distance SA between the legs 1135a is 0.3 to 0.7 of the distance PD of the wiring element 125.

[0216] The connecting piece 1135b connects the pair of legs 1135a in a direction that crosses the legs 1135a. The connecting pieces 1135b are separated by a predetermined distance S1, and the width S1 of the connecting piece 1135b is 1.3 mm to 1.9 mm.

[0217] The leg 1135a and the connecting piece 1135b that make up the conductor electrode 1135 have a width of 30 µm to 120 µm, similar to the width of the collecting or connecting electrode.

[0218] The wiring electrode 1137 electrically connects the two adjacent conductor electrodes 1135 in a direction that crosses the conductor electrode 1135. The wiring electrode 1137 has a width of 30 µm to 120 µm, similar to the conductor electrode 1135.

[0219] The wiring element 125 is located at the center of the conductor electrode 1135 and is connected thereto. The first pad 140 is selectively arranged at a location opposite the wiring element 125. An extension electrode 144 is arranged between the first pads 140 and connects the first pads 140 to each other.

[0220] Since the first pad 140 according to the fifth example of the first electrode is substantially the same as the first pad 140 according to the first example of the first electrode, further description may be brief or omitted entirely.

[0221] A width w4 of the extension electrode 144 is equal to or smaller than the width w1 of the first pad 140, is equal to or larger than the width of the leg 1135a or the connecting piece 1135b constituting the lead electrode 1135, and is smaller than the distance SA between the legs 1135a. The extension electrode 144 is a portion opposite to the wiring member 125 and connected to the wiring member 125 when the wiring member 125 is soldered to the first electrode 1130. Therefore, when the extension electrode 144 is formed in an opposite portion of the wiring member 125 and the first electrode 1130, a connection area between the wiring member 125 and the first electrode 1130 increases. Consequently, the connection strength therebetween can increase and the contact resistance can decrease.

[0222] In the fifth example of the first electrode, the conductor electrode 1135, the wiring electrode 1137, the first pad 140, and the extension electrode 144 can be formed simultaneously by the screen printing method. In this case, they can be made of the same metal material, such as silver (Ag). Alternatively, they can be formed individually by different methods.

[0223] Fig. 38 and Fig. 39 show that instead of the extension electrode 144, an auxiliary pad is formed between the first pads. Fig. 38 and Fig. The first electrode 1130 shown in Figure 39 differs from the one shown in Fig. 37 in that instead of the extension electrode 144, the auxiliary pads 141 and 142 are arranged between the first pads 140 and connect the first pads 140.

[0224] In the same way as with the extension electrode 144, the contact area between the auxiliary pads 141 and 142 and the wiring element 125 can be increased. Consequently, the connection strength between them can be increased and the contact resistance can be reduced. Furthermore, since the auxiliary pads 141 and 142 occupy a smaller area than the extension electrode 144, the manufacturing cost can be reduced.

[0225] Since the auxiliary pads 141 and 142 have been described above, further description can be kept brief or omitted entirely.

[0226] In Fig. 40, which shows the first electrode 1130, the first pad includes an extension pad 140e having a first size and an auxiliary pad 140a having a second size smaller than the first size.

[0227] In Fig. 40, the first electrode 1130 includes a collecting electrode 1131 and a connecting electrode 1133 in the same manner as in the examples described above.

[0228] The plurality of first pads 140 may selectively include the extension pads 140e and the auxiliary pads 140a at a location where the wiring elements 125 pass between the intersections of the collecting electrodes 1131 and the connecting electrodes 1133.

[0229] In Fig. 40, the extension pad 140e may have a first size, and the auxiliary pad 140a may have a second size that is smaller than the first size. Namely, the width or length of the extension pad 140e may be greater than the width or length of the auxiliary pad 140a.

[0230] The auxiliary pad 140a may be arranged between a pair of the extension pads 140e in the longitudinal direction of the wiring member 125.

[0231] In particular, the extension pad 140e in each of the plurality of solar cells may be positioned closer to an end portion of the front surface of the semiconductor substrate 15 than the auxiliary pad 140a along the longitudinal direction of the wiring member 125.

[0232] For example, the extension pad 140e may be arranged on the collecting electrode 1131 located on the outermost side among the collecting electrodes 1131 of the first electrode 1130 that crosses the wiring member 125 along the longitudinal direction of the wiring member 125 on the front surface of the semiconductor substrate 15 of each solar cell.

[0233] Accordingly, the two extension pads 140e may be formed on the upper and lower sides (i.e., the two outermost sides) of the semiconductor substrate 15 along the longitudinal direction of the wiring member 125. The plurality of auxiliary pads 140a may be formed between the extension pads 140e. However, the extension pads 140e are not limited to these and may be changed. For example, the plurality of extension pads 140e may be formed on each of the upper and lower sides (i.e., the two outermost sides) of the semiconductor substrate 15 along the longitudinal direction of the wiring member 125.

[0234] The auxiliary pads 140a can be formed at all intersections between the extension pads 140e, or can be arranged intermittently every two or every four rows. Since the number of auxiliary pads 140a is related to the connection strength of the wiring element 125 and the manufacturing cost, the number of auxiliary pads 140a is determined depending on the required connection strength and the manufacturing cost. Preferably, one pad 140a can be arranged every one to ten lines, and the number of pads 140a can be 6 to 48.

[0235] The width of the extension pad 140e may be greater than the width of the wiring element 125 and less than 2.5 mm. The length of the pad 140e may be greater than the width of the first electrode 1130 and less than 30 mm.

[0236] The size of the extension pad 140e may, for example, have a width (in a direction crossing the longitudinal direction of the wiring element) of 0.25 mm to 2.5 mm and a length (the extension direction of the wiring element) of 0.035 mm to 30 mm, preferably 0.4 mm to 6 mm. The size of the auxiliary pad 140a may have a width of 0.035 mm to 30 mm, preferably 0.25 mm to 2.5 mm, and a length of 0.1 mm to 1 mm.

[0237] Preferably, the width of the extension pad 140e may be equal to the width of the auxiliary pad 140a, and the length of the extension pad 140e may be three to ten times the length of the auxiliary pad 140a.

[0238] When the size of the extension pad 140e is larger than the size of the auxiliary pad 140a, the width of the extension pad 140e may be larger than the width of the auxiliary pad 140a when the length of the extension pad 140e is equal to the length of the auxiliary pad 140a. Alternatively, the length of the extension pad 140e may be larger than the length of the auxiliary pad 140a in a state where the width of the extension pad 140e is equal to the width of the auxiliary pad 140a. Alternatively, both the width and length of the extension pad 140e may be larger than the width and length of the auxiliary pad 140a. The embodiment of the invention includes all of the above examples.

[0239] Fig. 41 shows that the second electrode 1150 includes an extension pad and an auxiliary pad.

[0240] As in Fig. As shown in Figure 41, the second electrode 1150 may include a plurality of collecting electrodes 1151 and connecting electrodes 1153 in the same manner as the first electrode 1130. The connecting electrodes 1153 may be omitted if necessary or desired.

[0241] The collecting electrodes 1151 may be arranged parallel to each other and formed in the direction crossing the longitudinal direction of the wiring element 125.

[0242] The collecting electrode 1151 of the second electrode 1150 may include a plurality of second pads 140e' and 140a' formed at the intersections of the wiring elements 125 and the collecting electrode 1151.

[0243] The number of second pads 140e' and 140a' may be equal to or greater than six and may be equal to or less than the number of collecting electrodes 1151.

[0244] The second pads 140e' and 140a' may include an auxiliary pad 140a' and an extension pad 140e', each having a different size. In particular, the size of the extension pad 140e' may be larger than the size of the auxiliary pad 140a'. Thus, a width or length of the extension pad 140e' may be larger than a width or length of the auxiliary pad 140a'.

[0245] The extension pad 140e' may be arranged closer to an end portion of the rear surface of the semiconductor substrate 15 than to the auxiliary pad 140a' in each of the plurality of solar cells along the longitudinal direction of the wiring member 125.

[0246] For example, the extension pad 140e' may be arranged on the collecting electrode 1151 located on the outermost side among the collecting electrodes 1151 of the second electrode 1150 that crosses the wiring member 125 along the longitudinal direction of the wiring member 125 on the back surface of the semiconductor substrate 15 of each solar cell.

[0247] Accordingly, the extension pads 140e' may be formed on the upper and lower sides (i.e., the two outermost sides) of the semiconductor substrate 15 along the longitudinal direction of the wiring member 125. The plurality of auxiliary pads 140a' may be formed between the extension pads 140e'. However, the extension pads 140e' are not limited to this and may be changed. For example, the plurality of extension pads 140e' may be formed on each of the upper and lower sides (i.e., the two outermost sides) of the semiconductor substrate 15 along the longitudinal direction of the wiring member 125.

[0248] When the second electrode 1150 includes the extension pads 140e' and the auxiliary pads 140a' in the same manner as the first electrode 1130, at least one of the width, the length, or the plurality of the first pads 140e and 140a may be different from at least one of the width, the length, or the plurality of the second pads 140e' and 140a'.

[0249] For example, the number of first pads 140e and 140a formed on the front surface of the semiconductor substrate 15 may be greater than the number of second pads 140e' and 140a' formed on the back surface of the semiconductor substrate 15, and the size of each of the first pads 140e and 140a may be smaller than the size of each of the second pads 140e' and 140a'. Furthermore, the width of the collecting electrode 1151 formed on the back surface of the semiconductor substrate 15 may be greater than the width of the collecting electrode 1131 formed on the front surface of the semiconductor substrate 15.

[0250] Furthermore, the width of the extension pad 140e' may be greater than the width of the wiring element 125 and less than 2.5 mm. The length of the extension pad 140e' may be greater than the width of the first electrode 1130 and less than 30 mm.

[0251] For example, the width of the second pads 140e' and 140a' of the second electrode 1150 may be 0.25 mm to 2.5 mm, and the length of the second pads 140e' and 140a' may be longer than the length of the first pads 140e and 140a. For example, the length of the extension pad 140e' may be about 0.6 mm to 12 mm, preferably about 5.5 mm to 7.5 mm, and the length of the auxiliary pad 140a' may be about 0.2 mm to 3 mm, preferably about 0.6 mm to 1.2 mm.

[0252] Since light is incident on the front surface of the semiconductor substrate 15, the shading area of ​​the front surface of the semiconductor substrate 15 may increase as the size of the first pads of the front surface of the semiconductor substrate 15 increases, as does the size of the second pads of the back surface of the semiconductor substrate 15. The amount of light incident on the front surface of the semiconductor substrate 15 may decrease due to an increase in the shading area. Therefore, the embodiment of the invention may reduce the size of the pads and increase the number of pads to compensate for a decrease in the connection strength.

[0253] Preferably, but not necessarily, the width of the extension pads and the auxiliary pads of the front surface and the back surface of the semiconductor substrate 15 is equal to or larger than the width of the wiring element and equal to or smaller than five times thereof.

[0254] The embodiment of the invention in which a solar cell module with solar cells of conventional structure includes a reflector will be described below with reference to Fig. 42 to 45 described. Fig. 42 is a perspective view of the solar cell module. Fig. 43 is a cross-sectional view along the Fig. Line AA shown in Figure 42. Fig. 44 is a cross-sectional view taken along the Fig. Line BB shown in Figure 42. Fig. 45 shows a wiring element of the Fig. 42 solar cell module shown.

[0255] As in the Fig. As shown in FIGS. 42 to 45, the solar cell module according to the embodiment of the invention connects a plurality of solar cells arranged adjacent to each other using a plurality of wiring members 125, each having a thin thickness. The wiring member 125 is electrically connected to first electrodes 113 formed on a front surface of a first solar cell C1 of two adjacent solar cells, and is electrically connected to second electrodes 115 formed on a rear surface of a second solar cell C2 adjacent to the first solar cell C1.

[0256] The solar cell has a rectangular shape with a thin thickness and slanted or rounded edges. The solar cell measures approximately 156 mm long and 156 mm wide and has a thickness of 150 µm to 200 µm.

[0257] The first electrodes 113 are formed on a front surface of a semiconductor substrate 111 onto which light is incident and are connected to the wiring element 125 via a first pad 140. The first electrodes 113 collect charge carriers of a conductivity type opposite to a conductivity type of the semiconductor substrate 111. For example, if the semiconductor substrate 111 is a p-type semiconductor substrate, the first electrodes 113 can collect electrons.

[0258] The semiconductor substrate 111 forms a pn junction and is an n- or p-type semiconductor substrate containing impurities of a first conductivity type.

[0259] The second electrodes 115, which have a similar shape to the first electrodes 113, are formed on a rear surface of the semiconductor substrate 111 and are connected to the wiring element 125 via a second pad 160. The second electrodes 115 collect carriers of a conductivity type opposite to the conductivity type of the first electrodes 113.

[0260] The first electrode 1130 and the second electrode 1150 are described in detail below.

[0261] A backside field region 154 is located between the semiconductor substrate 111 and the second electrode 1150. The backside field region 154 is a region more heavily doped with impurities of the same conductivity type as the semiconductor substrate 111 than the semiconductor substrate 111, and is locally formed at a location corresponding to the second electrode 1150.

[0262] The backfield region 154 of the same conductivity type as the semiconductor substrate 111 may be n-type if the semiconductor substrate 111 is n-type. In this case, the backfield region 154 may be formed by injecting phosphorus (P), an example of an impurity, into the back surface of the semiconductor substrate 111. Preferably, the backfield region 154 may be formed locally by implanting impurities into the back surface of the semiconductor substrate 111 using an ion implantation method.

[0263] A potential barrier is formed by a difference between the impurity concentrations of the semiconductor substrate 111 and the backside field region 154, and prevents or reduces charge carriers of the same conductivity type as the semiconductor substrate 111 from moving to the back surface of the semiconductor substrate 111. Therefore, the backside field region 154 can prevent recombination and / or disappearance of charge carriers of different conductivity types on and around the surface of the semiconductor substrate 111.

[0264] In the embodiment of the invention, the backside field region 154 is not formed on the entire back surface of the semiconductor substrate 111, but on some electrodes. However, the backside field region 154 may be formed on the entire back surface of the semiconductor substrate 111.

[0265] The solar cells with the configuration described above are connected to each other via the wiring element 125.

[0266] As in (A) of Fig. 45, the wiring element 125 may be in the form of a wire with a circular cross-section. (B) of Fig. 45 shows a cross section of the wiring element 125.

[0267] As in Fig. As shown in Figure 45, the wiring element 125 has a structure in which a cladding layer 125a is deposited on a core layer 125b with a small thickness (e.g., about 12 µm or less). The total thickness of the wiring element 125 is 250 µm to 550 µm.

[0268] The core layer 125b is made of a metal material with good conductivity, such as Ni, Cu, Ag, and Al. The cladding layer 125a is made of Pb, Sn, or a metal material with a chemical formula represented by SnIn, SnBi, SnPb, SnCuAg, and SnCu, and contains a solder. Thus, the cladding layer 125a may be soldered.

[0269] When connecting two adjacent solar cells using the wiring element 125, 10 to 15 wiring elements 125 can be used if the semiconductor substrate is 156 mm long and 156 mm wide. The number of wiring elements 125 can vary depending on the size of the semiconductor substrate, the width, the thickness, the pitch of the electrodes, etc.

[0270] So far, in the embodiment of the invention, the wiring element 125 has been described as having a wire shape with a circular cross section. However, the cross section of the wiring element 125 can have various shapes, including a rectangle and an oval.

[0271] The wiring member 125 electrically connects the two adjacent first and second solar cells C1 and C2 by connecting one side of the wiring member 125 to the first electrode 1130 of the first solar cell C1 via the first pad 140 and the other side of the wiring member 125 to the second electrode 1150 of the second solar cell C2 via the second pad 160. A preferred method for connecting the electrodes to the wiring member uses soldering to melt and bond the material or a conductive adhesive in which conductive particles are contained in a resin having adhesion.

[0272] In the embodiment of the invention, a first pad 140 and a second pad 160 are arranged at an intersection of the first electrode 1130 and the wiring element 125, and at an intersection of the second electrode 1150 and the wiring element 125. The first and second pads 140 and 160 increase the crossing area of ​​the first electrode 1130 and the wiring element 125, and the crossing area of ​​the second electrode 1150 and the wiring element 125. Therefore, when the wiring element 125 is connected to the first electrode 1130 and the second electrode 1150, the first and second pads 140 and 160 reduce the contact resistance and increase the connection strength between the electrodes 113 and 115 and the wiring element 125.

[0273] As an example of the soldering method, the wiring elements 125 are arranged on both the front surface and the back surface of each of the two adjacent solar cells, and are arranged opposite the first electrodes 113 and the second electrodes 115 of each of the two adjacent solar cells. In this state, the cladding layers 125a of the wiring elements 125 are heated to a temperature equal to or higher than a melting temperature for several seconds. While the cladding layers 125a are melted and cooled, the wiring elements 125 are fixed to the first and second electrodes 113 and 115.

[0274] In the embodiment of the invention, a reflector 170 is arranged between the adjacent solar cells. The adjacent solar cells are separated from each other by a predetermined distance in the longitudinal direction of the wiring element 125, and a gap IA exists between the adjacent solar cells. The reflector 170 is positioned in the gap IA and scatters the light incident on the gap IA. Therefore, the reflector 170 causes the light to fall on the adjacent solar cell.

[0275] The first electrode 1130 of the solar cell module having the configuration described above will be described below with reference to Fig. 46 described in detail.

[0276] As in Fig. 46, the first electrode 1130 includes a collecting electrode 1131 and a connecting electrode 1133.

[0277] The collecting electrode 1131 has a predetermined width and extends in one direction, for example, in a direction that crosses the longitudinal direction of the wiring element 125. The collecting electrodes 1131 are arranged parallel to each other and form a strip-like array. The collecting electrode 1131 has a width of 35 µm to 100 µm, and the pitch Pf between the collecting electrodes 1131 is 1.2 mm to 2.2 mm. Other values ​​for the collecting electrode 1131 may also be used. For example, the width and pitch of the collecting electrodes 1131 can be adjusted depending on various variables.

[0278] The connecting electrode 1133 has a predetermined width and extends in a direction that crosses the collecting electrode 1131, namely, in the same direction as the longitudinal direction of the wiring member 125. The connecting electrodes 1133 electrically and physically connect the collecting electrodes 1131.

[0279] A width of the connecting electrode 1133 is substantially equal to or greater than a width of the collecting electrode 1131 and smaller than a width of the first pad 140. For example, the width of the connecting electrode 1133 may be 30 µm to 120 µm. A distance Bdf between the connecting electrodes 1133 may be 5 mm to 23 mm and less than ten times the distance Pf between the collecting electrodes 1131.

[0280] Alternatively, the width of the connection electrode 1133 may be greater than the width of the collecting electrode 1131 and equal to or less than the horizontal width wfh of the first pad 140.

[0281] Since the connecting electrode 1133 is not essential with the above-described configuration, the first electrode 1130 may include only the collecting electrodes 1131 without the connecting electrode 1133. Omitting the connecting electrode 1133 can increase the light incidence area and reduce the manufacturing cost.

[0282] The first pads 140 are selectively formed at the intersections between the collecting electrodes 1131 and the connecting electrodes 1133. A vertical width wfv of the first pad 140 is greater than the width of the collecting electrode 1131 and is less than 30 mm. A horizontal width wfh of the first pad 140 is greater than the width of the connecting electrode 1133 and is less than 2.5 mm. For example, the horizontal width wfh of the first pad 140 can be 0.25 mm to 2.5 mm.

[0283] Preferably, but not necessarily, the first pads 140 are formed at all intersections of the collecting electrodes 1131 and the connecting electrodes 1133, respectively. However, the first pads 140 may be formed every two rows of the collecting electrodes 1131 based on a connecting electrode 1133 to consider manufacturing costs, efficiency, etc. Fig. 46 shows that the first pads 140 are formed at the intersections every 2*n rows of the collecting electrodes 1131 in a longitudinal direction of the connecting electrode 1133, where n is a natural number.

[0284] Therefore, when the 12 connecting electrodes 1133 and the 100 collecting electrodes 1131 are formed, the total number of the first pads 140 is 50*12.

[0285] The collecting electrode 1131, the connecting electrode 1133, and the first pad 140 can be fabricated simultaneously using the screen printing process. In this case, the collecting electrode 1131, the connecting electrode 1133, and the first pad 140 can be made of the same material, e.g., silver (Ag). If necessary or desired, the components can also be fabricated separately.

[0286] The wiring element 125 is arranged directly on the connection electrode 1133 and extends in a direction parallel to the connection electrode 1133. Thus, the wiring element 125 is arranged opposite the connection electrode 1133. A width Da of the wiring element 125 is 250 µm to 500 µm and is smaller than the horizontal width wfh of the first pad 140.

[0287] Since the wiring element 125 is soldered in a state where the wiring element 125 is disposed on the connection electrode 1133, the wiring element 125 is connected to both the connection electrode 1133 and the first pad 140. Therefore, the contact resistance between the electrode and the wiring element can decrease, and the efficiency of the solar cell can increase. The connection strength of the wiring element can increase.

[0288] The second electrode 1150 will be described below with reference to Fig. 47 described in detail.

[0289] As in Fig. 47, the second electrode 1150 includes a collecting electrode 1151 and a connecting electrode 1153 in the same manner as the first electrode 1130. In the following description, the collecting electrode 1131 and the connecting electrode 1133 of the first electrode 1130 are referred to as the front collecting electrode 1131 and the front connecting electrode 1133, respectively, and the collecting electrode 1151 and the connecting electrode 1153 of the second electrode 1150 are referred to as the rear collecting electrode 1151 and the rear connecting electrode 1153, respectively, so that the first and second electrodes 113 and 115 are not confused with each other.

[0290] The rear collecting electrode 1151 has a predetermined width and extends in a direction, for example, a direction that crosses the longitudinal direction of the wiring element 125, and thus has a strip shape. The rear collecting electrodes 1151 are arranged parallel to each other and form a strip-like arrangement.

[0291] The rear collecting electrode 1151 has a width of 35 µm to 120 µm, and the distance Pb between the rear collecting electrodes 1151 is 1.2 mm to 2.2 mm in the same manner as the front collecting electrode 1131. Preferably, the width of the rear collecting electrode 1151 may be larger than the width of the front collecting electrode 1131, or the distance Pb of the rear collecting electrode 1151 may be smaller than the distance of the front collecting electrode 1131.

[0292] As described above, the rear collecting electrode 1151 may be designed to be thicker than the front collecting electrode 1131.

[0293] The series resistance of the front surface of the semiconductor substrate is approximately 120 to 140 Ω / sq, and the series resistance of the back surface of the semiconductor substrate is approximately 20 to 40 Ω / sq, which is lower than the series resistance of the front surface of the semiconductor substrate. For this reason, the number of pads formed on the front surface of the semiconductor substrate is larger than the number of pads formed on the back surface of the semiconductor substrate to increase the contact area between the front collecting electrode 1131 and the wiring element 125. As a result, the pitch of the front collecting electrode 1131 is larger than the pitch Pb of the back collecting electrode 1151, and the number of back collecting electrodes 1151 may be larger than the number of front collecting electrodes 1131.

[0294] Fig. 47 shows, as an example, that the width of the front collecting electrode 1131 is equal to the width of the rear collecting electrode 1151.

[0295] The rear connection electrode 1153 has a predetermined width and extends in a direction that crosses the rear collecting electrode 1151, namely, in the same direction as the longitudinal direction of the wiring member 125. The rear connection electrodes 1153 electrically and physically connect the rear collecting electrodes 1151.

[0296] The rear connection electrode 1153 may have a width of 35 µm to 120 µm in the same manner as the rear collection electrode 1151, and the distance Bdb between the rear connection electrodes 1153 may be 9 mm to 13 mm.

[0297] Alternatively, the width of the rear connection electrode 1153 may be greater than the width of the rear collecting electrode 1151 and equal to or less than the horizontal width wbh of the second pad 160.

[0298] Since the rear connection electrode 1153 is not necessarily required with the above-described configuration, the second electrode 1150 may include only the rear collecting electrodes 1151 without the rear connection electrode 1153. Omitting the rear connection electrode 1153 can increase the light incidence area and reduce the manufacturing cost.

[0299] The second pads 160 are selectively formed at intersections of the rear collecting electrodes 1151 and the rear connecting electrodes 1153, so that the second electrode 1150 can be connected to the wiring member 125 via the second pads 160. In the embodiment of the invention, the size of the second pad 160 is larger than the size of the first pad 140. For example, a width of the second pad 160 may be 0.25 mm to 2.5 mm, and a length of the second pad 160 may be 0.1 mm to 12 mm.

[0300] In the embodiment of the invention, the number of second pads 160 is less than the number of first pads 140. Fig. 46 and Fig. 47, as an example, the number of second pads 160 is half the number of first pads 140. The embodiment of the invention describes, as an example, that both the size and number of first pads 140 are different from the size and number of second pads 160. However, the size of first pads 140 may be different from the size of second pads 160 in a state where the number of first pads 140 is equal to the number of second pads 160. Alternatively, the number of first pads 140 may be different from the number of second pads 160 in a state where the size of first pads 140 is equal to the size of second pads 160.

[0301] As in Fig. 47, the backfield region 154 is formed locally associated with the rear collecting electrodes 1151 of the second electrode 1150. The backfield region 154 is a region that is more heavily doped with impurities of the same conductivity type as the semiconductor substrate 111 than the semiconductor substrate 111. For example, if the impurity concentration of the semiconductor substrate 111 is 1*1016 atoms / cm 3 , the impurity atom concentration of the backfield region can be 154 2*1020 atoms / cm 3 be.

[0302] Since, in the embodiment of the invention, the rear field region 154 is formed locally associated with the rear collecting electrodes 1151, the rear field region 154 is separated from each other by a predetermined distance in the same way as the rear collecting electrodes 1151. Thus, the rear field regions 154 are arranged entirely in a strip shape.

[0303] As described above, the rear collecting electrodes 1151 are formed on the rear surface of the semiconductor substrate 111, with the backfield region 154, which is a heavily doped region, serving as the interface. Thus, the series resistance of the rear surface of the semiconductor substrate 111 is 20 to 40 Ω / sq, and the series resistance of the front surface of the semiconductor substrate is approximately 120 to 140 Ω / sq, which is about three times the series resistance of the rear surface.

[0304] This indicates that the contact resistance between the electrode and the wiring element 125 on the front surface of the semiconductor substrate is much greater than the contact resistance between the electrode and the wiring element 125 on the back surface of the semiconductor substrate. The result of an experiment conducted by the inventor shows that even when the number of second pads 160 was reduced to half the number of first pads 140, there was no impact on the efficiency of the solar cell. However, when the number of second pads 160 was less than half the number of first pads 140, the efficiency of the solar cell was greatly reduced.

[0305] Accordingly, the embodiment of the invention can maintain the efficiency of the solar cell while efficiently reducing the manufacturing cost by further reducing the number of the second pads 160 than the number of the first pads 140.

[0306] The rear collecting electrode 1151, the rear connecting electrode 1153, and the second pad 160 can be fabricated simultaneously using the screen printing process. In this case, the rear collecting electrode 1151, the rear connecting electrode 1153, and the second pad 160 can be made of the same material, e.g., silver (Ag). The components can also be fabricated separately if necessary or desired.

[0307] The wiring element 125 is located directly on the rear connection electrode 1153 and extends in a direction parallel to the rear connection electrode 1153. The pitch of the wiring element 125 is substantially equal to the pitch Bdb of the rear connection electrode 1153.

[0308] Since the wiring member 125 is soldered in a state where the wiring member 125 is arranged on the rear connection electrode 1153, the wiring member 125 is connected to both the rear connection electrode 1153 and the second pad 160 even if the number of the second pads 160 is relatively less than the number of the first pads 140. Therefore, the contact resistance between the electrode and the wiring member can decrease and the connection strength of the wiring member can increase.

[0309] Since, as described above, the number of second pads 160 is less than the number of first pads 140, the first and second pads 140 and 160 may be arranged differently according to the first and second electrodes 113 and 115. This will be explained below with reference to the Fig. 48 to 51 are described in detail.

[0310] In the Fig. 48 to 51 only briefly describe the components that are described in detail below. Fig. 48 to 51, the one-dot line indicates the front collecting electrode 1131, the dotted line indicates the rear collecting electrode 1151, and the two-dot line indicates the wiring element 125. It is assumed that the wiring elements 125 on the front surface and the rear surface of the semiconductor substrate are on the same line, and that the first and second pads 140 and 160 have the same size.

[0311] Fig. 48 shows that the front collecting electrode 1131 and the rear collecting electrode 1151, for example, have the same distance and are located on the same line.

[0312] The first pads 140 are formed at a position corresponding to a multiple of two, so that there is one intersection in the longitudinal direction of the wiring element 125 that does not include the first pad 140. The second pads 160 are formed at a position corresponding to a multiple of four, so that there are three intersections in the longitudinal direction of the wiring element 125 that do not include the second pad 160. Thus, the distance Pdf between the first pads 140 is smaller than the distance Pdb between the second pads 160.

[0313] In the embodiment of the invention, the second pads 160 are formed at a position corresponding to a multiple of four, and the first pads 140 are formed at a position corresponding to a multiple of two. Therefore, when the first pad 140 and the second pad 160 overlap each other, all the second pads 160 overlap the first pads 140, and a first pad 140 is arranged between the second pads 160.

[0314] In Fig. 49, the front collecting electrode 1131 and the rear collecting electrode 1151 are arranged in the same manner as in Fig. 48 are arranged on the same line. However, the second pad 160 does not overlap the first pad 140 and is arranged between the first pads 140. In this case, since the first pads 140 are formed at the position corresponding to a multiple of two and the second pads 160 are formed at the position corresponding to a multiple of four, all of the second pads 160 do not overlap the first pads 140.

[0315] Fig. 50 shows that the front collecting electrode 1131 and the rear collecting electrode 1151, for example, have the same distance and are not on the same line.

[0316] In this case, the front collecting electrode 1131 and the rear collecting electrode 1151 are not on the same line in the longitudinal direction of the wiring member 125 and are arranged alternately. Since the first pads 140 are formed at a position corresponding to a multiple of two and the second pads 160 are formed at a position corresponding to a multiple of four, the first pad 140 and the second pad 160 do not overlap.

[0317] Fig. 51 shows, for example, that the pitch of the front collecting electrode 1131 is greater than the pitch of the rear collecting electrode 1151. Since in this case the pitch of the front collecting electrode 1131 is greater than the pitch of the rear collecting electrode 1151, the front collecting electrode 1131 and the rear collecting electrode 1151 can be on the same line, adjacent to each other, or far apart. In other words, the front collecting electrode 1131 and the rear collecting electrode 1151 can be positioned differently.

[0318] Accordingly, the second pad 160 may be arranged at a position that overlaps the first pad 140, may be arranged at a position that partially overlaps the first pad 140, or may be arranged at another position.

[0319] A reflector of the Fig. 42 is described below with reference to the Fig. 52 to 58 described in detail. Fig. 52 is a plan view of a reflector positioned in a space. Fig. 53 is a cross-sectional view taken along the Fig. Line CC shown in Figure 52.

[0320] The second solar cell C2 is separated from the first solar cell C1 by a gap IA and connected to the first solar cell C1 via the wiring element 125. A reflector 170 is arranged in the gap IA.

[0321] The reflector 170 has the shape of a rectangular cuboid and is made of a metal material with good reflectivity. The reflector 170 can, for example, be made of the same material as the electrodes 113 and 115 or the same material as the wiring element 125.

[0322] The reflector 170 is fixedly connected to the wiring element 125 and is preferably soldered to the wiring element 125. When the wiring element 125 is soldered to the electrodes 113 and 115, the wiring element 125 is soldered to both the reflector 170 and the electrodes 113 and 115. This can reduce the number of manufacturing processes and lower manufacturing costs.

[0323] Preferably, the reflector 170 is connected to all the wiring elements 125 connected to the first and second solar cells C1 and C2. In the embodiment of the invention, the 12 wiring elements 125 are used to electrically connect the first and second solar cells C1 and C2, and the reflector 170 is soldered to all 12 wiring elements 125.

[0324] One side of the wiring element 125 is connected to the first electrode 1130 of the first solar cell C1, and the other side is connected to the second electrode 1150 of the second solar cell C2. Thus, the wiring element 125 is tilted at a predetermined angle in the gap IA, and the reflector 170 connected to the wiring element 125 is tilted at a predetermined angle in the gap IA.

[0325] Therefore, when the light enters the gap IA, it is reflected by the surface of the reflector 170 and falls on the second solar cell C2 adjacent to the first solar cell C1.

[0326] Fig. 54 shows that a portion of the reflector 170 is disposed on the first solar cell C1.

[0327] As in Fig. 54, the reflector 170 is arranged on the first solar cell C1 at a predetermined distance t from one end of the first solar cell C1 and is fixed to the wiring member 125. Namely, the reflector 170 is not separated from the first solar cell C1 and is partially located on the first solar cell C1.

[0328] One side of the wiring element 125 is connected to the first electrode 1130 of the first solar cell C1, and the other side is connected to the second electrode 1150 of the second solar cell C2. Thus, the wiring element 125 bends downward at the end of the first solar cell C1. When the wiring element 125, consisting of a metal layer, bends downward at the end of the first solar cell C1, a break is easily created in a portion of the wiring element 125.

[0329] However, since the reflector 170 is arranged on the bent portion of the wiring member 125 in the embodiment of the present invention, disconnection of the wiring member 125 can be prevented.

[0330] Fig. 55 shows that the reflector 170 is arranged on each of a front surface and a rear surface of the wiring member 125 in the gap IA.

[0331] The Fig. The reflector 170 shown in FIG. 55 is the same as the reflector 170 described above, except that the reflector 170 is disposed on both the front surface and the rear surface of the wiring member 125. Since the reflector 170 is disposed on both the rear surface and the front surface of the wiring member 125, disconnection of the wiring member 125 in the gap 1A can be prevented. Furthermore, since the reflector 170 formed of the metal material is additionally formed in the gap 1A, the wiring resistance of the wiring member 125 can be reduced.

[0332] Fig. 56 shows that uneven portions are formed on the surface of the reflector 170. As in Fig. As shown in Figure 56, when the light is reflected from the surface of the reflector 170, it is diffusely reflected from the surface of the reflector 170 because the surface of the reflector 170 contains the uneven portions. Therefore, the amount of light incident on the solar cell can be efficiently increased.

[0333] Fig. 57 shows that the surface of the reflector 170 forms an inclined surface Cs and that uneven portions 71 are formed on the inclined surface Cs. Fig. 57 shows that the inclined surface Cs of the reflector 170 is, for example, round. However, as long as the height of the inclined surface Cs varies depending on the position, the inclined surface Cs can have any shape. When the surface of the reflector 170 has the above-described inclined surface Cs, the light from the surface of the reflector 170 is refracted toward the solar cell by an amount corresponding to an inclination angle. Therefore, the amount of light incident on the solar cell can be efficiently increased.

[0334] So far, in the embodiment of the invention, it has been described that one reflector 170 is arranged in the gap IA. However, at least two reflectors 170 may also be arranged in the gap IA, as shown in Fig. 58. In this case, the plurality of reflectors 170 may be arranged as described above with reference to the Fig. 53 to 57, or they may each be configured to have different configurations. For example, if the two reflectors 170 are arranged in the gap IA, as shown in Fig. 58, one of the two reflectors 170 can have the configuration of Fig. 55 and the other the configuration of Fig. 57.

[0335] Fig. 58 shows that the reflector 170 is divided into the plurality of reflectors in the longitudinal direction of the wiring member 125. However, the reflector 170 may also be divided into the plurality of reflectors in a direction crossing the wiring member 125.

[0336] Although the embodiments have been described with reference to a number of illustrative embodiments, it is understood that numerous other modifications and embodiments may be devised by those skilled in the art within the scope of the principles of this disclosure. In particular, various variations and modifications in the components and / or arrangements of the subject combination assembly are possible within the scope of the disclosure, the drawings, and the appended claims. In addition to the variations and modifications in the components and / or arrangements, alternative uses will also be apparent to those skilled in the art. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] KR 10-2014-0084829

[0001] KR 10-2014-0100083

[0001] KR 10-2014-0100084

[0001]

Claims

[1] Solar cell module, comprising a plurality of solar cells each comprising a semiconductor substrate and first electrodes and second electrodes alternately arranged on a rear surface of the semiconductor substrate parallel to each other in a first direction; a plurality of first wiring elements arranged in a second direction crossing the first direction, electrically connected to the first electrodes through a conductive layer, insulated from the second electrodes, and configured to connect the plurality of solar cells in series; and a plurality of second wiring elements arranged in the second direction, electrically connected to the second electrodes through the conductive layer, insulated from the first electrodes, and configured to connect the plurality of solar cells in series, wherein each of the plurality of solar cells has first pads formed at intersections of the first wiring elements and the first electrodes, and second pads formed at intersections of the second wiring elements and the second electrodes, and wherein the first pads or the second pads comprise a first contact pad having a width greater than the width of each of the first and second electrodes, and at least one second contact pad having a size larger than the first contact pad. [2] The solar cell module according to claim 1, wherein at least a portion of the second electrodes insulated from the first wiring elements or at least a portion of the first electrodes insulated from the second wiring elements has an interruption portion in which the first electrodes or the second electrodes are not present. [3] The solar cell module according to claim 2, wherein a ridge is arranged at the interruption portion to selectively cover one end of the electrode. [4] The solar cell module according to any one of claims 1 to 3, wherein an insulating layer is formed in at least a portion of an insulating portion between a first electrode and a second wiring member or in at least a portion of an insulating portion between a second electrode and a first wiring member; and / or wherein the first and second pads are formed of the same material as the first electrodes or the second electrodes; and / or wherein at least one of the first and second pads has a slot with a thin groove. [5] The solar cell module according to any one of claims 1 to 4, wherein the first and second pads are formed of a different conductive material than the first electrodes or the second electrodes. [6] The solar cell module according to any one of claims 1 to 5, wherein each of the first and second electrodes has a width of 100 µm to 600 µm and a thickness of 0.1 µm to 10.0 µm. [7] The solar cell module according to any one of claims 1 to 6, wherein each of the plurality of solar cells has a plurality of dispersion layers disposed in a region between the insulating layer and the conductive layer and selectively fixing the first wiring elements and the second wiring elements to the semiconductor substrate. [8] The solar cell module according to claim 7, wherein the plurality of dispersion layers are formed of the same material as the first electrodes or the second electrodes or the same material as the insulating layer or the conductive layer.

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