WO2016065942A1

WO2016065942A1 - Solar cell array, solar cell module and manufacturing methodthereof

Info

Publication number: WO2016065942A1
Application number: PCT/CN2015/084064
Authority: WO
Inventors: Zhiqiang Zhao; Shuping KANG; Zhanfeng Jiang; Long He
Original assignee: Byd Company Limited
Priority date: 2014-10-31
Filing date: 2015-07-15
Publication date: 2016-05-06

Abstract

A solar array (30), a solar cell module (100) and a manufacturing method thereof are disclosed. The solar cell array (30) includes a plurality of cells (31) and conductive wires (32) constituted by a metal wire, any two adjacent cells (31) being connected by the conductive wires (32), the conductive wires (32) being connected with front secondary grid lines (312) of the cell (31), and a connection material layer (3121) being disposed at a position where the front secondary grid lines (312) are connected with the conductive wires (32).

Description

SOLAR CELL ARRAY, SOLAR CELL MODULE AND MANUFACTURING METHODTHEREOF

FIELD

The present disclosure relates to a field of solar cells, and more particularly, to a solar cell array, a solar cell module and a manufacturing method thereof.

BACKGROUND

A solar cell module is one of the most important components of a solar power generation device. Sunlight irradiates to a cell from its front surface and is converted to electricity within the cell. And secondary grid lines and primary grid lines are disposed on the front surface. Then the current is output via the welding strip that covers and is welded with the primary grid lines. The welding strip, the primary grid lines and the secondary grid lines cover part of the front surface of the cell, and then the part of sunlight irradiating to the primary grid lines and the secondary grid lines cannot be converted into electric energy. Thus, the welding strip, the primary grid lines and the secondary grid lines need to be designed as fine as possible in order for the solar cell module to receive more sunlight. However, the welding strip, the primary grid lines and the secondary grid lines serve to conduct current, and in terms of resistivity, the finer the welding strip, the primary grid lines and the secondary grid lines are, the smaller the cross section area thereof is, which causes greater loss of electricity due to increased resistivity. Therefore, the welding strip, the primary grid lines and the secondary grid lines shall be designed to get a balance between light blocking and electrical conduction, and to take the cost into consideration.

SUMMARY

The present disclosure is based on discoveries and understanding of the applicant to the following facts and problems.

In prior art, the primary grid lines and the secondary grid lines of the solar cells are made of expensive silver paste, which results in complicated manufacturing process of the primary grid lines and the secondary grid lines and high cost. When the cells are connected to form a module, the primary grid lines on the front surface of a cell are welded with back electrodes of another adjacent cell by a solder strip. Consequently, the welding of the primary grid lines is complicated, and the manufacturing cost of the cells is high.

In prior art, two primary grid lines are usually disposed on the front surface of the cell, and formed by applying silver paste to the front surface of the cell. The primary grid lines have a great width (for example, up to over 2mm) , which consumes a large amount of silver, and makes the cost high.

In prior art, a solar cell with three primary grid lines is provided, but this kind of solar cell still consumes a large amount of silver, and has a high cost. Moreover, three primary grid lines increase the shading area, which lowers the photoelectric conversion efficiency.

In addition, the number of the primary grid lines is limited by the solder strip. The larger the number of the primary grid lines is, the finer a single primary grid line is, and hence the solder strip needs to be narrower. Therefore, it is more difficult to weld the primary grid lines with the solder strip and to produce the narrower solder strip, and thus the cost of the welding rises up.

Consequently, in order to lower the cost and reduce the shading area, in the prior art, the silver primary grid lines printed on the cells are replaced with the metal wires, such as copper wires which serve as the primary grid lines to output the current. Since the silver primary grid lines are no longer used, the cost can be reduced considerably； the diameter of the copper wire is relatively small, so the shading area can be decreased. Thus, the number of the primary grid lines can be further increased up to 10, and the cell of this kind may be called a cell with multiple primary grid lines.

In prior art, there is a technical solution that the electrical connection of the metal wire and the cells is formed by laminating a transparent film pasted with metal wires and the cells, yet in this technical solution, the transparent film weakens the absorption rate of light, and a plurality of parallel metal wires may be in bad connection with the cells, which may affect the electrical performance. Thus, the number of the metal wires needs to be increased. If the number of the metal wires is increased, the absorption rate of light from the front surface is affected, and the performance of the product is degraded. Consequently, the product in this technical solution is not promoted and commercialized. Moreover, as said above, the number of the parallel metal wires is limited by the distance between adjacent metal wires.

For example, an American patent discloses a technical solution that metal wires are fixed by a transparent film. In the patent, multiple primary grid lines are arranged in parallel, and laminated onto the cells via the transparent film. When the transparent film is laminated with the primary grid lines, the laminating temperature is much lower than the melting temperature of the transparent film, so the transparent film cannot really be laminated with the cells due to the intervals among the primary grid lines, and there will be gap between the transparent film and the cells, so as to cause poor airtightness of the cell module. Moreover, the photoelectric conversion efficiency of the cells will be greatly influenced due to oxidation of air and moisture.

Thus, in the field of solar cells, the structure of the solar cell is not complicated, but each component is crucial. The production of the primary grid lines takes various aspects into consideration, such as shading area, electric conductivity, equipment, process, cost, etc., and hence becomes a difficult and hot issue in the solar cell technology. In the market, a solar cell with two primary grid lines is replaced with a solar cell with three primary grid lines in 2007 through huge efforts of those skilled in the art. A few factories came up with a solar cell with four primary grid lines around 2014. The concept of multiple primary grid lines is put forward in the recent years, but still there is no fairly mature product.

The present disclosure seeks to solve at least one of the problems existing in the related art to at least some extent.

The present disclosure provides a solar cell without primary grid lines, which needs neither primary grid line nor sold strip disposed on the cells, and thus lowers the cost. The solar cell without primary grid lines can be commercialized for mass production, easy to manufacture with simple equipment, especially in low cost, and moreover have high photoelectric conversion efficiency.

According to a first aspect of embodiments of the present disclosure, a solar cell array includes a plurality of cells and conductive wires constituted by a metal wire, any two adjacent cells being connected by the conductive wires, the conductive wires being connected with front secondary grid lines of the cell, and a connection material layer being disposed at a position where the front secondary grid lines are connected with the conductive wires.

In the solar cell array according to embodiments of the present disclosure, the connection material layer is disposed on the front secondary grid lines of the cell, so as to improve the connection performance of the conductive wires and the secondary grid lines, and to render the solar cell module relatively high photoelectric conversion efficiency.

According to a second aspect of embodiments of the present disclosure, the solar cell module includes an upper cover plate, a front adhesive layer, a cell array, a back adhesive layer and a back plate superposed in sequence, the cell array being a solar cell array according to the above embodiments.

According to a third aspect of embodiments of the present disclosure, a method for manufacturing a solar cell module includes: connecting adjacent cells by conductive wires constituted by a metal wire to form a cell array, the conductive wires being connected with front secondary grid lines of the cell, and a connection material layer being disposed at a position where the front secondary grid lines are connected with the conductive wires； superposing an upper cover plate, a front adhesive layer, the cell array, a back adhesive layer and a back plate in sequence, in which a front surface of the cell faces the front adhesive layer, a back surface thereof facing the back adhesive layer, and laminating them to obtain the solar cell module.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a plan view of a solar cell array according to an embodiment of the present disclosure；

Fig. 2 is a transverse sectional view of a solar cell array according to an embodiment of the present disclosure；

Fig. 3 is a longitudinal sectional view of a solar cell array according to embodiments of the present disclosure；

Fig. 4 is a schematic diagram of a metal wire for forming a conductive wire according to embodiments of the present disclosure；

Fig. 5 is a plan view of a solar cell array according to another embodiment of the present disclosure；

Fig. 6 is a plan view of a solar cell array according to another embodiment of the present disclosure；

Fig. 7 is a schematic diagram of a metal wire extending reciprocally according to embodiments of the present disclosure；

Fig. 8 is a schematic diagram of two cells of a solar cell array according to embodiments of the present disclosure；

Fig. 9 is a sectional view of a solar cell array formed by connecting, by a metal wire, the two cells according to Fig. 8；

Fig. 10 is a schematic diagram of a solar cell module according to embodiments of the present disclosure；

Fig. 11 is a sectional view of part of the solar cell module according to Fig. 10；

Fig. 12 is a schematic diagram of a solar cell array according to another embodiment of the present disclosure；

Fig. 13 is a schematic diagram of a secondary grid line according to an embodiment of the present disclosure.

Reference numerals:

100 cell module

10 upper cover plate

20 front adhesive layer

30 cell array

31 cell

31A first cell

31B second cell

311 cell substrate

312 secondary grid line

312A front secondary grid line

312B back secondary grid line

3121 connection material layer

313 back electric field

314 back electrode

32 conductive wire

32A front conductive wire

32B back conductive wire

321 metal wire body

322 coating layer

33 short grid line

40 back adhesive layer

50 back plate

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described in detail and examples of the embodiments will be illustrated in the drawings, where same or similar reference numerals are used to indicate same or similar members or members with same or similar functions. The embodiments described herein with reference to the drawings are explanatory, which are used to illustrate the present disclosure, but shall not be construed to limit the present disclosure.

Part of technical terms in the present disclosure will be elaborated herein for clarity and convenience of description.

According to embodiments of the present disclosure, a cell 31 includes a cell substrate 311, secondary grid lines 312 disposed on a front surface (the surface on which light is incident) of the cell substrate 311, a back electric field 313 disposed on a back surface of the cell substrate 311, and back electrodes 314 disposed on the back electric field 313. Thus, the secondary grid lines 312 can be called the secondary grid lines 312 of the cell 31, the back electric field 313 called the back electric field 313 of the cell 31, and the back electrodes 314 called the back electrodes 314 of the cell 31.

A cell substrate 311 can be an intermediate product obtained by subjecting, for example, a silicon chip to processes of felting, diffusing, edge etching and silicon nitride layer depositing. However, it shall be understood that the cell substrate 311 in the present disclosure is not limited to be formed by the silicon chip, but includes a thin-film solar cell substrate or any other suitable solar cell substrate 311.

In other words, the cell 31 comprises a silicon chip, some processing layers on a surface of the silicon chip, secondary grid lines on a shiny surface (namely a front surface) , and a back electric field 313 and back electrodes 314 on a shady surface (namely a back surface) , or includes other equivalent solar cells of other types without any front electrode.

A cell unit includes a cell 31 and conductive wires 32 constituted by a metal wire S.

A solar cell array 30 includes a plurality of cells 31 and conductive wires 32 which connect adjacent cells 31 and are constituted by the metal wire S. In other words, the solar cell array 30 is formed of a plurality of cells 31 connected by the conductive wires 32.

In the solar cell array 30, the metal wire S constitutes the conductive wires 32 of the cell unit, and extends between surfaces of the adjacent cells 31, which shall be understood in a broad sense that the metal wire S may extend between front surfaces of the adjacent cells 31, or may extend between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31. When the metal wire S extends between the front surface of the first cell 31 and the back surface of the second cell 31 adjacent to the first cell 31, the conductive wires 32 may include front conductive wires 32A extending on the front surface of the cell 31 and electrically connected with the secondary grid lines 312 of the cell 31, and back conductive wires 32B extending on the back surface of the cell 31 and electrically connected with the back electrodes 314 of the cell 31. Part of the metal wire S between the adjacent cells 31 can be called connection conductive wires.

It shall be noted that in the present disclosure, the metal wire S refers to a metal wire for extending reciprocally on the cells 31 to form the conductive wires 32； the conductive wires 32 can be the metal wire body 321, or can include the metal wire body 321 and a coating layer outside the metal wire body 321, i.e. the metal wire S can be the metal wire body 321, or can consist of the metal wire body 321 and the coating layer outside the metal wire body 321, in which the coating layer may be an alloy of low melting point.

In the present disclosure, preferably, the metal wire S is the metal wire body 321, or a copper wire or an aluminum wire. Preferably, the metal wire body 321 is the copper wire. Correspondingly, the metal wire S can be the copper wire or the aluminum wire. Preferably, the metal wire S is the copper wire. Preferably, the metal wire S has a circular cross section, such that more sunlight may irradiate onto the cell substrate, to further improve the photoelectric conversion efficiency.

In the present disclosure, the cell substrate 311, the cell 31, the cell unit, the cell array 30 and the solar cell module are only for the convenience of description, and shall not be construed to limit the present disclosure.

All the ranges disclosed in the present disclosure include endpoints, and can be individual or combined. It shall be understood that the endpoints and any value of the ranges are not limited to an accurate range or value, but also include values proximate the ranges or values.

In the present disclosure, the orientation terms such as “upper” and “lower” usually refer to the orientation “upper” or “lower” as shown in the drawings under discussion, unless specified otherwise； “front surface” refers to a surface of the solar cell module facing the light in practical application (for example, when the module is in operation) , i.e. a shiny surface on which light is incident, while “back surface” refers to a surface of the solar cell module back to the light in practical application.

In the following, the solar cell array 30 will be described according to the embodiments of the present disclosure.

As shown in Fig. 1 to Fig. 13, the solar cell array 30 according to the embodiments of the present disclosure comprises a plurality of cells 31 and conductive wires 32； the conductive wires 32 are connected with front secondary grid lines 312 of the cell 31； and a connection material layer 3121 is disposed at a position where the secondary grid lines 312 are connected with the conductive wires 32.

In other words, the solar cell array 30 of the present disclosure consists of at least two cells 31, and the adjacent cells 31 are connected by a plurality of conductive wires 32. The cell 31 includes a cell substrate 311 and secondary grid lines 312 disposed on the cell substrate 311. The conductive wires 32 and the secondary grid lines 312 are connected to realize connection of two adjacent cells 31. The connection material layer 3121 is disposed at a position where the secondary grid lines 312 need to be connected with the conductive wires 32, so as to connect the secondary grid lines 312 with the conductive wires 32 (as shown in Fig. 13) .

Thus, in the solar cell array 30 according to embodiments of the present disclosure, the connection material layer 3121 is disposed on the secondary grid lines 312 for connection with the conductive wires 32, so as to improve the connection performance of the conductive wires 32 and the secondary grid lines 312, to prevent the conductive wires 32 and the secondary grid lines 312 from drifting, and to render the solar cell module relatively high photoelectric conversion efficiency.

In some specific embodiments of the present disclosure, the connection material layer can be a welding layer or a conductive adhesive. In other words, in the present disclosure, the connection material layer 3121 on the secondary grid lines 312 can be a welding layer or a conductive adhesive.

Specifically, the welding layer is an alloy layer. The alloy layer contains Sn, Bi, and at least one of Cu, In, Ag, Sb, Pb and Zn. The alloy layer has a melting point of 100 to 220℃.

Alternatively, the welding layer has a thickness of 1 to 20μm, preferably 4 to 10μm. The welding layer has a width of 10 to 300μm, preferably 30 to 120μm. Further, the welding layer has a length of 0.1 to 2mm, preferably 0.25 to 1mm.

That’s to say, the welding layer may be a metal with a lower melting point or an alloy, for example a tin alloy. The tin alloy can be a conventional tin alloy, for example, containing Sn, and at least one of Bi, Pb, Ag and Cu, more specifically, i.e. SnBi, SnPb, SnBiCu, SnPbAg, etc, so as to avoid insufficient soldering between the secondary grid lines 312 of the cell and the conductive wires 32, and to render the solar cell module higher photoelectric conversion efficiency.

More specifically, the alloy layer with a low melting point may cover the secondary grid lines 312 completely or partially. When the alloy layer covers the secondary grid lines 312 partially, the alloy layer is, preferably, formed at a position where it is welded with the conductive wires 32. The thickness, width and length of the alloy layer can be determined in a relatively wide range. Preferably, the alloy layer has a thickness of 4 to 10μm, a width of 30 to 120μm, and a length of 0.25 to 1mm. The alloy for forming the alloy layer with a low melting point may be a conventional alloy with a low melting point which can be 100 to 200℃.

Preferably, the alloy with the low melting point contains Sn, and at least one of Bi, In, Ag, Sb, Pb and Zn, more preferably, containing Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn. Specifically, the alloy may be at least one of Sn-Bi alloy, In-Sn alloy, Sn-Pb alloy, Sn-Bi-Pb alloy, Sn-Bi-Ag alloy, In-Sn-Cu alloy, Sn-Bi-Cu alloy and Sn-Bi-Zn alloy. Most preferably, the alloy is Bi-Sn-Pb alloy, for example, containing 40 weight percent of Sn, 55 weight percent of Bi, and 5 weight percent of Pb (i.e. Sn40％ -Bi55％ -Pb5％) . The thickness of the alloy layer with the low melting point can be 0.001 to 0.06mm. The conductive wire 32 may have a cross section of 0.01 to 0.5mm². The metal wire can be conventional in the art, for example, a copper wire.

In some specific embodiments of the present disclosure, based on the total weight of the alloy, there are 15 to 60 weight percent of Bi, 30 to 75 weight percent of Sn, 0 to 20 weight percent of Cu, 0 to 40 weight percent of In, 0 to 3 weight percent of Ag, 0 to 20 weight percent of Sb, 0 to 10 weight percent of Pb, and 0 to 20 weight percent of Zn in the alloy. Preferably, the alloy is at least one selected from 50％ Sn-48％ Bi-1.5％ Ag-0.5％ Cu, 58％ Bi-42％ Sn, and 65％ Sn-20％ Bi-10％ Pb-5％ Zn.

According to an embodiment of the present disclosure, the adjacent cells 31 are connected by a metal wire S that extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31 to form a plurality of conductive wires 32； the conductive wires 32 are connected with the secondary grid lines 312 on the front surface of the cell 31, a connection material layer 3121 being disposed at a position where the secondary grid lines on the front surface of the cell are connected with the conductive wires.

That’s to say, in the present disclosure, two adjacent cells 31 are connected with the conductive wires 32, and the metal wire S extends reciprocally between the surfaces of the two adjacent cells. The secondary grid lines 312 of the cell 31 are provided with the connection material layer, so the conductive wires 32 are connected with the secondary grid lines 312 of the cell via the connection material layer 3121.

The cell unit is formed by the cell 31 and the conductive wires 32 constituted by the metal wire S which extends on the surface of the cell 31. In other words, the solar cell array 30 according to the embodiments of the present disclosure are formed with a plurality of cell units； the conductive wires 32 of the plurality of cells are formed by the metal wire S which extends reciprocally between the surfaces of the cells 31.

It shall be understood that the term “extending reciprocally” in the application can be called “winding” which refers to that the metal wire S extends between the surfaces of the cells 31 along a reciprocal route.

In the present disclosure, it shall be understood in a broad sense that “the metal wire S extends reciprocally between surfaces of the cells 31. For example, the metal wire S may extend reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31； the metal wire S may extend from a surface of the first cell 31 through surfaces of a predetermined number of middle cells 31 to a surface of the last cell 31, and then extends back from the surface of the last cell 31 through the surfaces of a predetermined number of middle cells 31 to the surface of the first cell 31, extending reciprocally like this.

In addition, when the cells 31 are connected in parallel by the metal wire S, the metal wire S can extend on front surfaces of two cells 31, such that the metal wire S constitutes front conductive wires 32A of two cells connected in parallel. Alternatively, a first metal wire S extends reciprocally on the front surface of the cell 31, and a second metal wire S extends reciprocally on the back surface of the cell 31, such that the first metal wire S constitutes front conductive wires 32A, and the second metal wire S constitutes back conductive wires 32B.

When the cells 31 are connected in series by the metal wire S, the metal wire S can extend reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31, such that part of the metal wire S which extends on the front surface of the first cell 31 constitutes front conductive wires 32A, and part thereof which extends on the back surface of the second cell 31 constitutes back conductive wires 32B. In the present disclosure, unless specified otherwise, the conductive wires 32 can be understood as the front conductive wires 32A, the back conductive wires 32B, or the combination thereof.

The term “extending reciprocally” can be understood as that the metal wire S extends reciprocally once to form to two conductive wires 32 which are formed by winding a metal wire S. For example, two adjacent conductive wires form a U-shape structure or a V-shape structure, yet the present disclosure is not limited to the above.

In the solar cell array 30 according to the embodiments of the present disclosure, the conductive wires 32 of the plurality of cells 31 are constituted by the metal wire S which extends reciprocally； and the adjacent cells 31 are connected by the conductive wires 32. Hence, the conductive wires 32 of the cells are not necessarily made of expensive silver paste, and can be manufactured in a simple manner without using a solder strip to connect the cells. It is easy and convenient to connect the metal wire S with the secondary grid lines and the back electrodes, so that the cost of the cells is reduced considerably.

Moreover, since the conductive wires 32 are constituted by the metal wire S which extends reciprocally, the width of the conductive wires 32 (i.e. the width of projection of the metal wire on the cell) may be decreased, thereby decreasing the shading area of the conductive wires 32. Further, the number of the conductive wires 32 can be adjusted easily, and thus the resistance of the conductive wires 32 is reduced, compared with the primary grid lines made of the silver paste, and the photoelectric conversion efficiency is improved. Since the metal wire S extends reciprocally to form the conductive wires, when the cell array 30 is used to manufacture the solar cell module 100, the metal wire S will not tend to shift, i.e. the metal wire is not easy to “drift” , which will not affect but further improve the photoelectric conversion efficiency.

In the solar cell array according to the embodiments of the present disclosure, since the conductive wires are constituted by the metal wire which extends reciprocally, the structure of the conductive wires that are arranged in a winding way between the adjacent cells 31 to extend reciprocally is a folded shape, which is easy to manufacture in low cost, and can improve the photoelectric conversion efficiency of the solar cell array. The conductive wires 32 are welded with the secondary grid lines 312, and the conductive wires 32 in the solar cell module will not drift and be insufficiently welded, so as to obtain relatively high photoelectric conversion efficiency.

Therefore, the solar cell array 30 according to the embodiments of the present disclosure has low cost and high photoelectric conversion efficiency.

In the following, the solar cell array 30 according to specific embodiments of the present disclosure will be described with reference to the drawings.

The solar cell array 30 according to a specific embodiment of the present disclosure is illustrated with reference to Fig. 1 to Fig. 3.

In the embodiment shown in Fig. 1 to Fig. 3, two cells in the solar cell array 30 are shown. In other words, it shows two cells 31 connected with each other via the conductive wires 32 constituted by the metal wire S.

It can be understood that the cell 31 comprises a cell substrate 311, secondary grid lines 312 (i.e. front secondary grid lines 312A) disposed on a front surface of the cell substrate 311, a back electric field 313 disposed on a back surface of the cell substrate 311, and back electrodes 314 disposed on the back electric field 313. In the present disclosure, it can be understood that the back electrodes 314 may be back electrodes of a traditional cell, for example, printed by the silver paste, or may be back secondary grid lines 312B similar to the secondary grid lines on the front surface of the cell substrate, or may be multiple discrete welding portions, unless specified otherwise. The secondary grid line refers to the secondary grid lines 312 on the front surface of the cell substrate 311, unless specified otherwise.

As shown in Fig. 1 to Fig. 3, the solar cell array in the embodiment includes two

cells

31A, 31B (called a first cell 31A and a second cell 31B respectively for convenience of description) . The metal wire S extends reciprocally between the front surface of the first cell 31A (a shiny surface, i.e. an upper surface in Fig. 2) and the back surface of the second cell 31B, such that the metal wire S constitutes front conductive wires of the first cell 31A and back conductive wires of the second cell 31B. The metal wire S is electrically connected with the secondary grid lines of the first cell 31A (for example, being welded or bounded by a conductive adhesive) , and electrically connected with the back electrodes of the second cell 31B.

In an embodiment of the present disclosure, back electrodes 314 are disposed on the back surface of the cell substrate 311, and the metal wire is welded with the back electrodes 314.

That’s to say, in the embodiment, front secondary grid lines 312A are disposed on the front surface of the cell substrate 311, and back electrodes 314 are disposed on the back surface of the cell substrate 311. When located on the front surface of the cell substrate 311, the conductive wires 32 are welded with front secondary grid lines 312A； when located on the back surface of the cell substrate 311, the conductive wires 32 are welded with the back electrodes 314 on the back surface of the cell substrate 311.

In some embodiments, the metal wire extends reciprocally between the first cell 31A and the second cell 31B for 1o to 60 times. Preferably, as shown in Fig. 1, the metal wire extends reciprocally for 12 times to form 24 conductive wires, and there is only one metal wire. In other words, a single metal wire extends reciprocally for 12 times to form 24 conductive wires, and the distance of the adjacent conductive wires can range from 2.5mm to 15mm. In this embodiment, the number of the conductive wires is increased, compared with the traditional cell, such that the distance between the secondary grid lines and the conductive wires which the current runs through is decreased, so as to reduce the resistance and improve the photoelectric conversion efficiency. In the embodiment shown in Fig. 1, the adjacent conductive wires form a U-shape structure, for convenience of winding the metal wire. Alternatively, the present disclosure is not limited to the above. For example, the adjacent conductive wires form a V-shape structure.

In addition, it is convenient to electrically connect the metal with the secondary grid lines and/or the back electrodes, and to avoid drifting of the metal wire in the connection process so as to guarantee the photoelectric conversion efficiency. The electrical connection of the metal with the cell substrate can be conducted when or before the solar cell module is laminated, and preference is given to the latter.

In some embodiments, preferably, before the metal wire contact the cells, the metal wire extends under strain, i.e. straightening the metal wire. After the metal wire is connected with the secondary grid lines and the back electrodes of the cell, the strain of the metal wire can be released, so as to further avoid the drifting of the conductive wires when the solar cell module is manufactured, and to guarantee the photoelectric conversion efficiency.

Fig. 5 is a schematic diagram of a solar cell array according to another embodiment of the present disclosure. As shown in Fig. 5, the metal wire extends reciprocally between the front surface of the first cell 31A and the front surface of the second cell 31B, such that the metal wire constitutes front conductive wires of the first cell 31A and front conductive wires of the second cell 31B. In such a way, the first cell 31A and the second cell 31B are connected in parallel. Of course, it can be understood that preferably the back electrodes of the first cell 31A and the back electrodes of the second cell 31B also can be connected via back conductive wires constituted by another metal wire which extends reciprocally. Alternatively, the back electrodes of the first cell 31A and the back electrodes of the second cell 31B can be connected in a traditional manner.

In the cell array 30, the cell 31 can be a conventional cell 31 in the art, for example, a polycrystalline silicon cell 31. The secondary grid lines 312 on the shiny surface of the cell 31 can be Ag, Cu, Sn, and tin alloy. The secondary grid line 312 has a width of 40 to 80μm and a thickness of 5 to 20μm； there are 50 to 120 secondary grid lines, a distance between adjacent secondary grid lines ranging from 0.5 to 3mm.

The back electrodes 314 on the back surface of the cell 31 can be made of Ag, Cu, Sn and tin alloys. The back electrodes 314 are usually in a ribbon pattern, and have a width of 1 to 4mm, and a thickness of 5 to 20μm.

The solar cell array 30 according to another embodiment of the present disclosure is illustrated with reference to Fig. 6.

The solar cell array 30 according to the embodiment of the present disclosure comprises n×m cells 31. In other words, a plurality of cells 31 are arranged in an n×m matrix form, n representing a column, and m representing a row. More specifically, in the embodiment, 36 cells 31 are arranges into six columns and six rows, i.e. n＝m＝6. It can be understood that the present disclosure is not limited thereto. For example, the column number and the row number can be different. For convenience of description, in Fig. 6, in a direction from left to right, the cells 31 in one row are called a first cell 31, a second cell 31, a third cell 31, a fourth cell 31, a fifth cell 31, and a sixth cell 31 sequentially； in a direction from up to down, the columns of the cells 31 are called a first column of cells 31, a second column of cells 31, a third column of cells 31, a fourth column of cells 31, a fifth column of cells 31, and a sixth column of cells 31 sequentially.

In a row of the cells, the metal wire extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31； in two adjacent rows of cells 31, the metal wire extends reciprocally between a surface of a cell 31 in a a^th row and a surface of a cell in a (a+1) ^th row, and m-1≥a≥1.

As shown in Fig. 6, in a specific example, in a row of the cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31, so as to connect the cells in one row in series. In two adjacent rows of cells 31, the metal wire extends reciprocally between a front surface of a cell 31 at an end of the a^th row and a back surface of a cell 31 at an end of the (a+1) ^th row, to connect the two adjacent rows of cells 31 in series.

More preferably, in the two adjacent rows of cells 31, the metal wire extends reciprocally between the surface of the cell 31 at an end of the a^th row and the surface of the cell 31 at an end of the (a+1) ^th row, the end of the a^th row and the end of the (a+1) ^th row located at the same side of the matrix form, as shown in Fig. 6, located at the right side thereof.

More specifically, in the embodiment as shown in Fig. 6, in the first row, a first metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of the second cell 31；a second metal wire extends reciprocally between a front surface of the second cell 31 and a back surface of a third cell 31； a third metal wire extends reciprocally between a front surface of the third cell 31 and a back surface of a fourth cell 31； a fourth metal wire extends reciprocally between a front surface of the fourth cell 31 and a back surface of a fifth cell 31； a fifth metal wire extends reciprocally between a front surface of the fifth cell 31 and a back surface of a sixth cell 31.In such a way, the adjacent cells 31 in the first row are connected in series by corresponding metal wires.

A sixth metal wire extends reciprocally between a front surface of the sixth cell 31 in the first row and a back surface of a sixth cell 31 in the second row, such that the first row and the second row are connected in series. A seventh metal wire extends reciprocally between a front surface of the sixth cell 31 in the second row and a back surface of a fifth cell 31 in the second row； a eighth metal wire extends reciprocally between a front surface of the fifth cell 31 in the second row and a back surface of a fourth cell 31 in the second row, until a eleventh metal wire extends reciprocally between a front surface of a second cell 31 in the second row and a back surface of a first cell 31 in the second row, and then a twelfth metal wire extends reciprocally between a front surface of the first cell 31 in the second row and a back surface of a first cell 31 in the third row, such that the second row and the third row are connected in series. Sequentially, the third row and the fourth row are connected in series, the fourth row and the fifth row connected in series, the fifth row and the sixth row connected in series, such that the cell array 30 is manufacture. In this embodiment, a bus bar is disposed at the left side of the first cell 31 in the first row and the left side of the first cell 31 in the sixth row respectively； a first bus bar is connected with the conductive wire extending from the left side of the first cell 31 in the first row, and a second bus bar is connected with the conductive wire extending from the left side of the first cell 31 in the sixth row.

As said above, the cells in the embodiments of the present disclosure are connected in series by the conductive wires –the first row, the second row, the third row, the fourth row, the fifth row and the sixth row are connected in series by the conductive wires. As shown in the figures, alternatively, the second and third row, and the fourth and fifth rows can be connected in parallel with a diode respectively to avoid light spot effect. The diode can be connected in a manner commonly known to those skilled in the art, for example, by a bus bar.

However, the present disclosure is not limited to the above. For example, the first and second rows can be connected in series, the third and fourth rows connected in series, the fifth and sixth rows connected in series, and meanwhile the second and third rows are connected in parallel, the fourth and fifth connected in parallel. In such a case, a bus bar can be disposed at the left or right side of corresponding rows respectively.

Alternatively, the cells 31 in the same row can be connected in parallel. For example, a metal wire extends reciprocally from a front surface of a first cell 31 in a first row through the front surfaces of the second to sixth cells 31.

In some specific embodiments of the present disclosure, the binding force between the metal wire and the cells 31 ranges from 0.1N to 0.8N. That’s to say, the binding force between the conductive wires 32 and the cells 31 ranges from 0.1N to 0.8N. Preferably, the binding force between the metal wire and the cells ranges from 0.2N to 0.6N. so as to secure the welding between the cells and the metal wire, to avoid sealing-off of the cells in the operation and the transferring process and performance degradation due to poor connection, and to lower the cost.

The solar cell module 100 according to embodiments of the present disclosure is illustrated with reference to Fig. 10 and Fig. 11.

As shown in Fig. 10 and Fig. 11, the solar cell module 100 according to embodiments of the present disclosure includes an upper cover plate 10, a front adhesive layer 20, the cell array 30, a back adhesive layer 40 and a back plate 50 superposed sequentially along a direction from up to down.

The front adhesive layer 20 and the back adhesive layer 40 are adhesive layers commonly used in the art. Preferably, the front adhesive layer 20 and the back adhesive layer 40 are polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA) . In the present disclosure, polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA) are conventional products in the art, or can be obtained in a method known to those skilled in the art.

In the embodiments of the present disclosure, the upper cover plate 10 and the back plate 50 can be selected and determined by conventional technical means in the art. Preferably, the upper cover plate 10 and the back plate 50 can be transparent plates respectively, for example, glass plates.

In the process of manufacturing the solar cell module 100, the conductive wires can be first bounded or welded with the secondary grid lines and the back electrodes of the cell 31, and then superposed and laminated.

Other components of the solar cell module 100 according to the present disclosure are known in the art, which will be not described in detail herein.

In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156mm×156mm, the solar cell module has a series resistance of 380 to 440mΩ per 60 cells. The present disclosure is not limited to 60 cells, and there may be 30 cells, 72 cells, etc. When there are 72 cells, the series resistance of the solar cell module is 456 to 528mΩ, and the electrical performance of the cells is better.

In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156mm×156mm, the solar cell module has an open-circuit voltage of 37.5-38.5V per 60 cells. The present disclosure is not limited to 60 cells, and there may be 30 cells, 72 cells, etc. The short-circuit current is 8.9 to 9.4A, and has nothing to do with the number of the cells.

In some specific embodiments of the present disclosure, the solar cell module has a fill factor of 0.79 to 0.82, which is independent from the dimension and number of the cells, and can affect the electrical performance of the cells.

In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156mm×156mm, the solar cell module has a working voltage of 31.5-32V per 60 cells. The present disclosure is not limited to 60 cells, and there may be 30 cells, 72 cells, etc. The working current is 8.4 to 8.6A, and has nothing to do with the number of the cells.

In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156mm×156mm, the solar cell module has a conversion efficiency of 16.5-17.4％, and a power of 265-280W per 60 cells.

A method for manufacturing the solar cell module 100 according to the embodiments of the present disclosure will be illustrated with respect to Fig. 7 to Fig. 9.

Specifically, the method according to the embodiments of the present disclosure includes the following steps: connecting adjacent cells by conductive wires 32 constituted by a metal wire S to form a cell array, the conductive wires 32 being connected with front secondary grid lines 312A of the cell, and a connection material layer 3121 being disposed at a position where the front secondary grid lines 312A are connected with the conductive wires 32.

Preferably, the metal wire S extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31； the metal wire S is welded with the front secondary grid line 312A of the first cell 31 by the connection material layer 3121, and connected with the a back electrode on a back surface of the second cell 31, so as to form a cell array.

The connection material layer can be a welding layer or a conductive adhesive, and the welding layer can be an alloy with low melting point.

Then, the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 are superposed in sequence, in which the front surface of the cell 31 faces the front adhesive layer 20, the back surface thereof facing the back adhesive layer 4. Finally, they are laminated to obtain the solar cell module 100.

The method includes the steps of preparing a solar array 30, superposing the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 in sequence, and laminating them to obtain the solar cell module 100. It can be understood that the method further includes other steps, for example, sealing the gap between the upper cover plate 10 and the back plate 50 by a sealant, and fixing the above components together by a U-shape frame, which are known to those skilled in the art, and thus will be not described in detail herein.

The method includes a step of forming a plurality of conductive wires by a metal wire which extends reciprocally surfaces of cells 31 and is electrically connected with the surfaces of cells 31, such that the adjacent cells 31 are connected by the plurality of conductive wires to constitute a cell array 30.

Specifically, as shown in Fig. 7, the metal wire extends reciprocally for 12 times under strain. As shown in Fig. 8, a first cell 31A and a second cell 31B are prepared. As shown in Fig. 9, a front surface of the first cell 31A is connected with a metal wire, and a back surface of the second cell 31B is connected with the metal wire, such that the cell array 30 is formed. Fig. 9 shows two cells 31. As said above, when the cell array 30 has a plurality of cells 31, the metal wire which extends reciprocally connects the front surface of the first cell 31A and the back surface of the second cell 31B adjacent to the first cell 31A, i.e. connecting secondary grid lines of the first cell 31A with back electrodes of the second cell 31B by the metal wire. The metal wire extends reciprocally under strain from two clips at two ends thereof.

In the embodiment shown in Fig. 9, the adjacent cells are connected in series. As said above, the adjacent cells can be connected in parallel by the metal wire based on practical requirements.

The cell array 30 obtained is superposed with the upper cover plate 10, the front adhesive layer 20, the back adhesive layer 40 and the back plate 50 in sequence, in which the front surface of the cell 31 faces the front adhesive layer 20, and the back surface thereof faces the back adhesive layer 40, and then they are laminated to obtain the solar cell module 100. It can be understood that the metal wire can be bounded or welded with the cell 31 when or before they are laminated.

In the following, the solar cell module 100 of the present disclosure will be described with respect to specific examples.

Example 1

Example 1 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.

(1) Manufacturing conductive wires

A copper wire is used, and the cross section of the copper wire is 0.04mm².

(2) Manufacturing a solar cell module 100

A POE adhesive layer in 1630×980×0.5mm is provided (melting point: 65℃) , and a glass plate in 1633×985×3mm and a polycrystalline silicon cell 31 in 156×156×0.21mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60μm in width, 9μm in thickness) , each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7mm. An alloy layer of Sn40％ -Bi55％ -Pb5％ coats the portion where each secondary grid line is needs to be connected with the conductive wire, by screen printing. The alloy layer has a thickness of 10μm, a width of 60μm, and a length of 0.4mm. The cell 31 has five back electrodes (tin, 1.5mm in width, 10μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31mm.

The cells 31 are arranged in a matrix form. In two adjacent cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under strain. The metal wire extends reciprocally when its two ends are strained by two clips, so as to form 15 parallel conductive wires. The secondary grid lines of a first cell 31 are welded with the conductive wires, and the back electrodes of a second cell 31 are welded with the conductive wires, at 160℃ of the welding temperature. The distance between parallel adjacent conductive wires is 9.9mm. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the shiny surface of the cell 31 faces the front adhesive layer, and the shady surface of the cell 31 faces the back adhesive layer, and finally they are laminated in a laminator so as to obtain the solar cell module A1.

Example 2

Example 2 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.

(1) Manufacturing a primary grid line

A copper wire is used, and the cross section of the copper wire is 0.04mm².

(2) Manufacturing a solar cell module

A EVA adhesive layer in 1630×980×0.5mm is provided (melting point: 60℃) , and a glass plate in 1633×985×3mm and a polycrystalline silicon cell 31 in 156×156×0.21mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60μm in width, 9μm in thickness) , each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the two adjacent secondary grid lines is 1.7mm. The cell 31 has five back electrodes (tin, 1.5mm in width, 10μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in the longitudinal direction, and the distance between the two adjacent back electrodes is 31mm.

The cells 31 are arranged in a matrix form. An epoxy resin conductive adhesive layer is disposed at a portion where each secondary grid line needs to be connected with the conductive wire, by screen printing. The epoxy resin conductive adhesive layer has a thickness of 5μm, a width of 30μm, and a length of 0.6mm. In two adjacent cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under strain, so as to form 20 parallel conductive wires. The secondary grid lines of the first cell 31 are welded with the conductive wires, and the back electrodes of the second cell 31 are welded with the conductive wires. The distance between parallel adjacent conductive wires is 7mm. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the shiny surface of the cell 31 faces the front adhesive layer, and the shady surface of the cell 31 faces the back adhesive layer. Finally, they are laminated in a laminator so as to obtain a solar cell module A2.

Example 3

The difference between Example 3 and Example 1 lies in that the cells 31 are arranged in a matrix form, and in two adjacent cells, each of the fifteen parallel metal wires, by wiredrawing, is strained by the clips at its ends to flatten the cells. The tension of the clips is 2N. An alloy layer of Sn40％ -Bi55％ -Pb5％ is disposed at the portion where the secondary grid line on the front surface of the cell 31 contacts the metal wire, by screen printing. The alloy layer has a thickness of 15μm, a width of 100μm, and a length of 0.8mm. Each of the fifteen parallel metal wires is welded with secondary grid lines on a front surface of a first cell 31 respectively, and welded with back electrodes on a back surface of a second cell 31. The distance between the parallel adjacent conductive wires is 9.9mm. In such a way, a solar cell module A3 is obtained.

Example 4

The difference between Example 3 and Example 1 lies in that the cells 31 are arranged in a matrix form, and in two adjacent cells, each of the fifteen parallel metal wires, by wiredrawing, is strained by the clips at its ends to flatten the cells. The tension of the clips is 2N. An epoxy resin conductive adhesive layer is disposed at the portion where the secondary grid line on the front surface of the cell 31 contacts the metal wire, by screen printing. The alloy layer has a thickness of 3μm, a width of 80μm, and a length of 1mm. Each of the fifteen parallel metal wires is welded with secondary grid lines on a front surface of a first cell 31 respectively, and welded with back electrodes on a back surface of a second cell 31. The distance between the parallel adjacent conductive wires is 9.9mm. In such a way, a solar cell module A4 is obtained.

Comparison example 1

The difference between Comparison example 1 and Example 1 lies in that the cells are arranged in a matrix form； the fifteen metal wires connected in series are pasted on the transparent film, and then pasted on the cells. In two adjacent cells, the metal wire connects a front surface of a first cell and a back surface of a second cell. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the shiny surface of the cell 31 faces the front adhesive layer, and the shady surface of the cell 31 faces the back adhesive layer. Finally, they are laminated in a laminator so as to obtain a solar cell module D2.

Example 5

The solar cell module is manufactured according to the method in Example 2, but the difference compared with Example 2 lies in that short grid lines 33 (silver, 0.1mm in width) are disposed on the secondary grid lines of the shiny surface of the cell 31, and are perpendicular to the secondary grid lines for connecting part of the secondary grid lines at the edges of the shiny surface of the cell 31 with the conductive wires, as shown in Fig. 12, so as to obtain a solar cell module A5.

Example 6

The solar cell module is manufactured according to the method in Example 2, but the difference compared with Example 2 lies in that the cells 31 of six columns and six rows are connected in such a manner that in two adjacent rows of cells, the conductive wires extend from a shiny surface of a cell at an end of the a^th row (a≥1) to form electrical connection with a back surface of a cell 31 at an adjacent end of the (a+1) ^th row, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows of cells 31 are arranged in perpendicular to the conductive wires for connecting the adjacent cells 31 in the two rows. In such a way, the solar cell module A6 is obtained.

Testing example 1

(1) Whether the metal wire in the solar cell module drifts is observed with the naked eyes；

(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions: 1000W/m² of light intensity, AM1.5 spectrum, and 25℃. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 1.

Table 1

The fill factor refers to a ratio of the power at the maximum power point of the solar cell module and the maximum power theoretically at zero resistance, and represents the proximity of the actual power with respect to the theoretic maximum power, in which the greater the value is, the higher the photoelectric conversion efficiency is. Generally, the series resistance is small, so the fill factor is great. The photoelectric conversion efficiency refers to a ratio of converting the optical energy into electric energy by the module under a standard lighting condition (1000W/m² of light intensity) . The series resistance is equivalent to the internal resistance of the solar module, in which the greater the value is, the poorer the performance of the module is. The fill factor represents a ratio of the actual maximum power and the theoretical maximum power of the module, in which the greater the value is, the better the performance of the module is. The open-circuit voltage refers to the voltage of the module in an open circuit under a standard lighting condition. The short-circuit current refers to the current of the module in a short circuit under a standard lighting condition. The working voltage is the output voltage of the module working with the largest power under a standard lighting condition. The working current is the output current of the module working with the largest power under a standard lighting condition. The power is the maximum power which the module can reach under a standard lighting condition.

It can be indicated from Table 1 that for the solar cell module according to the embodiments of the present disclosure, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.

In the specification, it is to be understood that terms such as “central, ” “longitudinal, ” “lateral, ” “length, ” “width, ” “thickness, ” “upper, ” “lower, ” “front, ” “rear, ” “left, ” “right, ” “vertical, ” “horizontal, ” “top, ” “bottom, ” “inner, ” “outer, ” “clockwise, ” and “counterclockwise” should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the present disclosure be constructed or operated in a particular orientation.

In addition, terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance or to imply the number of indicated technical features. Thus, the feature defined with “first” and “second” may comprise one or more of this feature. In the description of the present disclosure, “aplurality of” means two or more than two, unless specified otherwise.

In the present disclosure, unless specified or limited otherwise, a structure in which a first feature is “on” or “below” a second feature may include an embodiment in which the first feature is in direct contact with the second feature, and may also include an embodiment in which the first feature and the second feature are not in direct contact with each other, but are contacted via an additional feature formed therebetween. Furthermore, a first feature “on, ” “above, ” or “on top of” a second feature may include an embodiment in which the first feature is right or obliquely “on, ” “above, ” or “on top of” the second feature, or just means that the first feature is at a height higher than that of the second feature； while a first feature “below, ” “under, ” or “on bottom of” a second feature may include an embodiment in which the first feature is right or obliquely “below, ” “under, ” or “on bottom of” the second feature, or just means that the first feature is at a height lower than that of the second feature.

Reference throughout this specification to “an embodiment, ” “some embodiments, ” or “some examples” means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, these terms throughout this specification do not necessarily refer to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

Although embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes, modifications, alternatives and variations can be made in the embodiments without departing from the scope of the present disclosure.

Claims

A solar cell array, comprising a plurality of cells and conductive wires constituted by a metal wire, any two adjacent cells being connected by the conductive wires, the conductive wires being connected with front secondary grid lines of the cell, and a connection material layer being disposed at a position where the front secondary grid lines are connected with the conductive wires.
The solar cell array according to claim 1, wherein the connection material layer is a welding layer or a conductive adhesive.
The solar cell array according to claim 2, wherein the welding layer is an alloy layer.
The solar cell array according to claim 3, wherein the welding layer contains Sn, Bi, and at least one of Cu, In, Ag, Sb, Pb and Zn.
The solar cell array according to claim 3 or 4, wherein the alloy layer has a melting point of 100 to 220℃.
The solar cell array according to claim 2, wherein the welding layer has a thickness of 1 to 20μm.
The solar cell array according to claim 6, wherein the welding layer has a thickness of 4 to 10μm.
The solar cell array according to claim 2, wherein the welding layer has a width of 10 to 300μm.
The solar cell array according to claim 8, wherein the welding layer has a width of 30 to 120μm.
The solar cell array according to claim 2, wherein the welding layer has a length of 0.1 to 2mm.
The solar cell array according to claim 10, wherein the welding layer has a length of 0.25 to 1mm.
The solar cell array according to claim 4, wherein based on the total weight of the alloy, there are 15 to 60 weight percent of Bi, 30 to 75 weight percent of Sn, 0 to 20 weight percent of Cu, 0 to 40 weight percent of In, 0 to 3 weight percent of Ag, 0 to 20 weight percent of Sb, 0 to 10 weight percent of Pb, and 0 to 20 weight percent of Zn in the alloy.
The solar cell array according to claim 8, wherein the alloy is at least one selected from 50％Sn-48％Bi-1.5％Ag-0.5％Cu, 58％Bi-42％Sn, and 65％Sn-20％Bi-10％Pb-5％Zn.
The solar cell array according to claim 1, wherein the adjacent cells are connected by a metal wire that extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell to form a plurality of conductive wires, the conductive wires being connected with the secondary grid lines by the connection material layer.
The solar cell array according to claim 14, wherein the metal wire extends reciprocally between a front surface of the first cell and a back surface of the second cell.
The solar cell array according to claim 15, wherein a back electrode is disposed on a back surface of the cell； a back conductive wire constituted by the metal wire is disposed on the back surface of the cell； the back conductive wire is connected with the back electrode.
The solar cell array according to claim 14, wherein the metal wire extends reciprocally between the front surface of the first cell and the back surface of the second cell for 10 to 60 times.
The solar cell array according to claim 10, wherein a distance between two adjacent conductive wires ranges from 2.5mm to 15mm.
The solar cell array according to claim 14, wherein the two adjacent conductive wires form a U-shape structure or a V-shape structure.
The solar cell array according to claim 14, wherein the cells are arranged in an n×m matrix form, n representing a column, and m representing a row；

in a row of cells, the metal wire extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell； in two adjacent rows of cells, the metal wire extends reciprocally between a surface of a cell in a a^th row and a surface of a cell in a (a+1) ^th row； and m-1≥a≥1.
The solar cell array according to claim 20, wherein in two adjacent rows of cells, the metal wire extends reciprocally between a surface of a cell at an end of the a^th row and a surface of a cell at an end of the (a+1) ^th row, the end of the a^th row and the end of the (a+1) ^th row located at the same side of the matrix form.
The solar cell array according to claim 20, wherein in a row of cells, the metal wire extends reciprocally between a front surface of a first cell and a back surface of a second cell adjacent to the first cell；

in two adjacent rows of cells, the metal wire extends reciprocally between a front surface of a cell at an end of the a^th row and a back surface of a cell at an end of the (a+1) ^th row, to connect the two adjacent rows of cells in series.
The solar cell array according to any one of claims 14 to 22, wherein there is a metal wire extending reciprocally between adjacent cells in a row； and there is a metal wire extending reciprocally between cells in adjacent rows.
The solar cell array according to claim 14, wherein there is a metal wire.
The solar cell array according to any one of claims 14 to 24, wherein the secondary grid line has a width of 40 to 80μm and a thickness of 5 to 20μm； there are 50 to 120 secondary grid lines, a distance between adjacent secondary grid lines ranging from 0.5 to 3mm.
The solar cell array according to any one of claims 14 to 25, wherein the metal wire is a copper wire.
The solar cell array according to any one of claims 14 to 26, wherein the metal wire is connected with the secondary grid line under strain.
A solar cell module, comprising an upper cover plate, a front adhesive layer, a cell array, a back adhesive layer and a back plate superposed in sequence, the cell array being a solar cell array according to any one of claims 1 to 24.
A method for manufacturing a solar cell module, comprising:

connecting adjacent cells by conductive wires constituted by a metal wire to form a cell array, the conductive wires being connected with front secondary grid lines of the cell, and a connection material layer being disposed at a position where the front secondary grid lines are connected with the conductive wires；

superposing an upper cover plate, a front adhesive layer, the cell array, a back adhesive layer and a back plate in sequence, in which a front surface of the cell faces the front adhesive layer, a back surface thereof facing the back adhesive layer, and laminating them to obtain the solar cell module.
The method according to claim 29, wherein the connection material layer is a welding layer or a conductive adhesive.
The method according to claim 30, wherein the metal wire extends reciprocally between a front surface of a first cell and a back surface of a second cell adjacent to the first cell； the metal wire is welded with a secondary grid line on a front surface of the first cell by the welding layer, and connected with the a back electrode on a back surface of the second cell.
The method according to claim 29, wherein the metal wire expends reciprocally under strain.