WO2016065946A1

WO2016065946A1 - Solar cell array, solar cell module and manufacturing method thereof

Info

Publication number: WO2016065946A1
Application number: PCT/CN2015/084094
Authority: WO
Inventors: Zhiqiang Zhao; Liguo Wang; Ye Tian; 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 cell 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) arranged in an n×m matrix form, in which in a row of cells, adjacent cells (31) are connected by the plurality of conductive wires (32), and at least two conductive wires (32) are constituted by a metal wire extending reciprocally between surfaces of the adjacent cells (31); in two adjacent rows of cells (31), a cell (31) in a a^th row and a cell in a (a+1) ^th row are connected by the plurality of conductive wires (32), and at least two conductive wires (32) are constituted by a metal wire extending reciprocally between a surface of a cell (31) in a a^th row and a surface of a cell (31) in a (a+1) ^th row. A secondary grid line (312) and a short grid line (33) are disposed on a front surface of the cell (31), and the secondary grid line (312) includes a middle secondary grid line (3122) intersected with the conductive wire (32) and an edge secondary grid line (3121) non-intersected with the conductive wire (32), the short grid line (33) being connected with the conductive wire (32) or at least one middle secondary grid line (3122).

Description

SOLAR CELL ARRAY, SOLAR CELL MODULE AND MANUFACTURING METHOD THEREOF

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. Primary grid lines and secondary grid lines are disposed on the front surface and cover part of the front surface of the cell body. As such, the part of sunlight irradiating to the primary grid lines and the secondary grid lines are blocked by the grid lines and cannot be converted into electric energy. Thus, 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 primary grid lines and the secondary grid lines serve to conduct current, and in terms of resistivity, the finer the primary grid lines and the secondary grid lines are, the smaller the cross section area thereof are, which causes greater loss of electricity due to increased resistivity. Therefore, the primary grid lines and the secondary grid lines shall be designed to achieve a balance between light blocking and electrical conduction, and to take the cost into consideration.

The current solar cell module mainly has a structure of three primary grid lines, and the primary grid lines are formed by printing silver paste on the surface of the cell and sintering. In such a way, the manufacturing of the primary grid lines has high cost but mature process.

Generally, if there are more primary grid lines of the solar cell, the distance between the secondary grid lines and the primary grid lines will be shorter, along with less resistance of the cells connected in series, and better electricity generation performance. However, when the number of the primary grid lines is increased, the width of the primary grid lines is decreased (otherwise the shading area is increased to lower the electricity generation efficiency) , such that it is more difficult to weld the cells in series. Currently, at most five primary grid lines of the cells connected in series can be welded successfully, but the product of five primary grid lines is not commercialized because the cost performance is lower than the product of three primary grid lines.

The solar cell with multiple primary grid lines (over 10 primary grid lines) can only use the metal wire as the primary grid lines, rather than adopt the primary grid lines sintered by silver paste, due to the limit of series welding technology.

The selection of material for the metal wire shall take cost, conductivity and weldability into consideration. In common metals, the conductivity of copper is slightly lower than silver but has a much lower cost than silver, so copper is given preference. However, the weldability of copper primary grid lines and silver secondary grid lines is not good at a low temperature, and the welding below 200℃ (too high temperature may damage the cells) .

Moreover, the metal wire cannot only serve as the primary grid lines on ordinary cells, but also as the welding strip to connect the ordinary cells. The metal wire bridges two adjacent cells–connecting the front surface of one cell with the back surface of the other cell to constitute a series circuit.

Generally, the solar cell module utilizes solar cells with three primary grid lines, and each row of cells is connected by a bus bar. In this connection mode, the current path is longer, along with greater resistance, which tends to cause insufficient welding, and hence affects the photoelectric conversion efficiency of the solar cell module.

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 causes a complicated manufacturing process of the primary grid lines and the secondary grid lines and high cost. When the cells are connected into 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.

However, 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.

Consequently, from the perspective of lowering the cost and reducing the shading area, the prior art replaces the silver primary grid lines printed on the cell with metal wires, for example, copper wires. The copper wires are welded with the secondary grid lines to output the current. Since the silver primary grid lines are no longer used, the cost can be reduced considerably. The copper wire has a smaller diameter to reduce the shading area, so the number of the copper wires can be raised up to 10. This kind of cell may be called a cell without primary grid lines, in which the metal wire replaces the silver primary grid lines and solder strips in the traditional solar cells.

After a long time research, the inventor of the present disclosure finds if a cell is manufacture in this way that multiple parallel metal wires are drawn simultaneously, cut off, and then welded to the cell simultaneously, due to limit of sophistication of equipment and process, for example, the influence of stress, the solar cell is bent to some extent when disposed at a free state, so the metal wire needs to remain kind of strained to flatten the cell (a test proves that the minimum strain is at least 2N for a copper wire with a diameter of 0.2mm) . In order to keep the strain, each metal wire needs to be provided with clips or similar equipment at the two ends thereof, and the equipment occupies certain space, but the space in the cell is limited. Thus, in the prior art, at most ten metal wires can be drawn, fixed and welded to a single cell, and it will be difficult to increase the number of the metal wires. The larger the number of the metal wires is, the more there are free ends, such that the equipment needs to control more metal wires at the same time, which is demanding as for the wiredrawing equipment. Moreover, the space of the solar cells is limited. For example, the dimension of a single cell is 156mm×156mm. In such limited space, the multiple metal wires need to be controlled accurately at the same time, which is demanding as for the equipment, especially as for the accuracy. Currently, it is still hard to control and weld multiple metal wires simultaneously in actual production, so the number of the conductive wires is limited, usually at most ten around, which is difficult to realize.

In order to solve the above problem, relevant patents (US20100275976 and US20100043863) provide a technical solution that multiple metal wires are fixed on a transparent film. That’s to say, multiple parallel metal wires are fixed on the transparent film by adhesion； then, the transparent film bound with the multiple parallel metal wires is attached to the cell； finally the metal wires contact with the secondary grid lines on the cell by lamination. By this method, the multiple metal wires are fixed via the transparent film, which solves the problem of controlling the multiple metal wires simultaneously, and further increases the number of the metal wires. However, the technical solution almost abandons the welding process. That’s to say, the metal wires are not connected with the secondary grid lines by the welding process； instead, the metal wires contact with the secondary grid lines by the laminating process, so as to output the current.

The above technical solution can further increase the number of the metal wires, but the transparent film may affect the light absorption, which causes kind of shading, and thus lowers the photoelectric conversion efficiency.

Furthermore, the above technical solution cannot connect the metal wires with the secondary grid lines by the welding process, because the melting temperature of the transparent film must be higher than the welding temperature (usually around 140℃) , otherwise the transparent film will melt in the process of welding, which may lose the function of fixing the metal wires, and then the metal wires drift, resulting in poor welding effects.

Moreover, it is known to those skilled in the art that the solar cells in use are sealed to prevent moisture and air from penetrating the cells, which may cause corrosion and short circuit. The encapsulating material at present is EVA whose melting point is 70℃ to 80℃, much lower than the welding temperature. If the welding process is employed, as said above, the melting temperature of the transparent film must be higher than the welding temperature, and the melting point of the encapsulating material. Thus, in the encapsulating process, the encapsulating material (EVA) will melt at the encapsulating temperature, but the transparent film will not, such that the melting encapsulating material cannot penetrate the solid transparent film to completely seal the cells. Hence, the sealing effect is poor, and the actual product tends to fail. In terms of encapsulating, the melting temperature of the transparent film needs to be lower than the welding temperature, which is an evident paradox.

Therefore, the technical solution of fixing the metal wires via the transparent film cannot adopt the welding process to weld the metal wires with the secondary grid lines, or the metal wires are in contact with the secondary grid lines on the cells, i.e. the metal wires are only put on the secondary grid lines. Thus, the connection strength of the metal wires and the secondary grid lines is so low that the metal wires tend to separate from the secondary grid lines in the laminating process or in use, which causes bad contact, low efficiency of the cells, or even failure thereof. Consequently, the product in this technical solution is not promoted and commercialized. There is no fairly mature solar cell without primary grid lines.

Especially, the metal wires are relatively fine and in a large number. Moreover, the metal wires are connected afterwards and have free ends. Due to the problem concerning the sophistication of the equipment, it cannot be guaranteed that the fine and many metal wires are connected with the cells in accurate positions, especially the accuracy of the positions of the ends. In order to avoid short circuits caused by the metal wire extending beyond the cells, the conductive wires are generally formed in the cells, in which case part of the secondary grid lines at the edges of the cells cannot be connected with the conductive wires well, thereby resulting in current loss.

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, and the number of the conductive wires disposed the cell can be increased up to 20 or even greater. In the present disclosure, the conductive wires are constituted by a few metal wires which extend reciprocally, so as to reduce the free ends. Consequently, the number of the metal wires is not limited by the space, and more conductive wires may be disposed on the cell to facilitate the welding between the multiple conductive wires and the secondary grid lines on the cell. Meanwhile, in the solar cell without primary grid lines of the present disclosure, the conductive wires and the secondary grid lines are connected by welding, which is reliable and simple to manufacture, and has good sealability and high efficiency. Thus, the solar cells satisfy the practical requirements and may be commercialized for mass production.

Thus, the present disclosure provides a solar cell array that is easy to manufacture in low cost, and improves the photoelectric conversion efficiency.

The present disclosure further provides a solar cell module having the above solar cell array. The solar cell module is easy to manufacture in low cost, and improves the photoelectric conversion efficiency.

The present disclosure further provides a method for manufacturing the solar cell module.

According to a first aspect of embodiments of the present disclosure, a solar cell array includes a plurality of cells arranged in an n×m matrix form, in which in a row of cells, adjacent cells are connected by a plurality of conductive wires, at least two conductive wires constituted by a metal wire which extends reciprocally between surfaces of adjacent cells； in two adjacent rows of cells, a cell in a a^th row and a cell in a (a+1) ^th row are connected by the plurality of conductive wires, and at least two conductive wires are constituted by a metal wire extending reciprocally between a surface of a cell in a a^th row and a surface of a cell in a (a+1) ^th row, n representing a column, m representing a row and m-1≥a≥1； a secondary grid line and a short grid line are disposed on a front surface of the cell, and the secondary grid line includes a middle secondary grid line intersected with the conductive wire and an edge secondary grid line non-intersected with the conductive wire, the short grid line being connected with the edge secondary grid line and being connected with the conductive wire or at least one middle secondary grid line. The metal wire is coated with a welding layer by which the metal wire is welded with the middle secondary grid line.

In the solar cell array according to embodiments of the present disclosure, the conductive wires are constituted by the metal wire which extends reciprocally. The conductive wires of this structure extend reciprocally between two adjacent cells in a winding way to form a folded shape, which is easy to manufacture in low cost, and can improve the photoelectric conversion efficiency of the solar cell array. Moreover, the conductive wires are arranged in a winding way to avoid failure of the whole conductive wires when a single primary grid line breaks off or is insufficiently welded, so as to avoid instability of the cells. The conductive wires and the secondary grid lines are welded, such that the conductive wires in the solar cell module will not drift or be insufficiently welded, and the solar cell module obtains relatively high photoelectric conversion efficiency.

Further, the cells in each row are directly connected by the conductive wires, which will use fewer bus bars, and reduces the connection distance, resistance and insufficient welding. The conductive wires are arranged in a winding way to avoid all the problems due to cutting the conductive wires. Moreover, the short grid lines are disposed on part of the secondary grid lines at the edges of the shiny surface of the cell, so as to avoid partial current loss because the conductive wires arranged in the winding way cannot reach the secondary grid lines at the edges of the cell. The primary grid liens are constituted by the metal wire coated with an alloy layer with a low melting point, so as to improve welding performance of the conductive wires with the secondary grid lines and/or back electrodes. The conductive wires in the solar cell module will not drift or be insufficiently welded, and have 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: forming a plurality of conductive wires by a metal wire which extends reciprocally a surface of a first cell of a plurality of cells and a surface of a second cell thereof, such that the adjacent cells are connected by the plurality of conductive wires to constitute a cell array, wherein the plurality of cells are arranged in an n×m matrix form； in a row of cells, a 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 to obtain the cell array, n representing a column, m representing a row and m-1≥a≥1, a secondary grid line and a short grid line being disposed on a front surface of the cell, the secondary grid line including a middle secondary grid line intersected with the conductive wire and an edge secondary grid line non-intersected with the conductive wire, the short grid line being connected with the edge secondary grid line, and being connected with the conductive wire or at least one middle secondary grid line, the metal wire being coated with a welding layer by which the metal wire is welded with the middle secondary grid line； 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 winding method in the present disclosure facilitates electrical connection of the metal wire with the cell, and the good connection performance is beneficial, especially, to welding of the metal wire with the cell, and can avoid insufficient welding of the conductive wires. The solar cell manufactured has beautiful design and good performance. Moreover, a suitable number of conductive wires can be manufactured, as long as they are strained by two clips, which is independent from space limit. The process is easy to realize with simple equipment, which can be industrialized. The edge secondary grid lines at the edges of the cell which are not intersected with the conductive wires are electrically with the conductive wires, so as to reduce current loss. The short grid lines can be formed by screen printing silver, which is easy to realize and to control with high accuracy. The electric connection of all the fine grid lines and the conductive wires can be guaranteed, which lowers the sophistication and difficulty of the process, and improves the photoelectric conversion efficiency of the cell considerably.

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 longitudinal sectional view of a solar cell array according to an embodiment of the present disclosure；

Fig. 3 is a transverse 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 metal wire under strain according to Comparison Example 1.

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 edge secondary grid line

3122 middle secondary grid line

313 back electric field

314 back electrode

32(32C) conductive wire

32A front conductive wire

32B back conductive wire

321 metal wire body

322 welding layer

33 short grid line

34 clip

40 back adhesive layer

50 lower cover 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 one embodiment 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.

The 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.

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.

In the present disclosure, descriptive terms, such as 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 scope of 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 with respect to the drawings.

As shown in Fig. 1 to Fig. 12, the solar cell array 30 according to the embodiments of the present disclosure comprises a plurality of cells 31 arranged in an n×m matrix form. In a row of cells 31, a 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 to form a plurality of conductive wires 32, the adjacent cells 31 being connected by the plurality of conductive wires 32.

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 31 in a (a+1) ^th row to connect the cells in two adjacent rows, in which n represents a column, m represents a row, and m-1≥a≥1.

The present disclosure is not limited to that multiple conductive wires 32 are formed by winding the metal wire –the conductive wires can be partially or completely formed by winding the metal wire. In other words, part of the conductive wires can be formed by non-winded metal wires. The present disclosure aims to reduce free ends, to enlarge operation space. The reciprocal extension can be back and forth once. There is no limit to the termination point of the reciprocal extension –the starting point and the termination point can be at the same cell or at different cells, as long as the metal wire is winded.

Secondary grid lines 312 and short grid lines 33 are disposed on a front surface of the cell 31, the secondary grid lines 312 include middle secondary grid lines 3122 intersected with the conductive wires 32 and edge secondary grid lines 3121 non-intersected with the conductive wires 32；the short grid lines 33 are connected with the edge secondary grid lines 3121, and are connected with the conductive wires 32 or at least one middle secondary grid line 3122. The metal wire is coated with a welding layer by which the metal wire is welded with the middle secondary grid lines 3122.

In other words, the solar cell array 30 according to the embodiments of the present disclosure is formed with at least four cells 31 which are arranged in a matrix form of two columns and two rows. Two adjacent cells 31 in the same row are connected by a plurality of conductive wires 32 constituted by the metal wire S which extends reciprocally between two adjacent cells 31. Two adjacent cells 31 in the same column are connected by a plurality of conductive wires 32 constituted by the metal wire S which extends reciprocally between two adjacent cells 31.

Each cell 31 comprises a cell substrate 311, secondary grid lines 312 and short grid lines 33 disposed on a front surface of the cell substrate 311, and back electrodes 314 disposed on a back surface of the cell substrate 311. Adjacent cells 31 are connected by a plurality of conductive wires 32 constituted by a metal wire S which extends reciprocally between the adjacent cells 31.

The secondary grid lines 312 located at a side surface of the cell substrate 311 comprises two parts –one part of the secondary grid lines 312 intersected with the conductive wires 32 and located in a middle position of the cell substrate 311 to form middle secondary grid lines 3122； the other part of the secondary grid lines 312 non-intersected with the conductive wires 32 and located at an edge of one side away from the conductive wires 32 to form edge secondary grid lines 3121.

The edge secondary grid lines 3121 are provided with short grid lines 33 connected with the conductive wires 32 or at least one middle secondary grid line 3122. The short grid lines 33 are located at the edges of the cell 31 where the conductive wires 32 cannot reach when being winded, so as to avoid current loss.

That’s to say, each cell 31 is provided with secondary grid lines 312 and short grid lines 33 on the front surface of the cell, and provided with back electrodes 314 on the back surface thereof. The two adjacent cells are connected by the plurality of conductive wires 32. The conductive wires 32 are constituted by the metal wire which extends reciprocally between two adjacent cells, and are provided with a welding layer for being welded with the secondary grid lines 312. The conductive wires 32 are welded with the secondary grid lines 312.

In the solar cell array according to embodiments of the present disclosure, the conductive wires are constituted by the metal wire which extends reciprocally. The conductive wires of this structure extend reciprocally between two adjacent cells in a winding way to form a folded shape, which is easy to manufacture in low cost, and can improve the photoelectric conversion efficiency of the solar cell array. Moreover, the conductive wires are arranged in a winding way to avoid failure of the whole conductive wires when a single primary grid line breaks off or is insufficiently welded, so as to avoid instability of the cells. The conductive wires and the secondary grid lines are welded, such that the conductive wires in the solar cell module will not drift or be insufficiently welded, and the solar cell module obtains relatively high photoelectric conversion efficiency. Further, the cells in each row are directly connected by the conductive wires, which will use fewer bus bars, and reduces the connection distance, resistance and insufficient welding. The conductive wires are arranged in a winding way to avoid all the problems due to cutting the conductive wires. Moreover, the short grid lines are disposed on part of the secondary grid lines at the edges of the shiny surface of the cell, so as to avoid partial current loss because the conductive wires arranged in the winding way cannot reach the secondary grid lines at the edges of the cell. The primary grid liens are constituted by the metal wire coated with an alloy layer with a low melting point, so as to improve welding performance of the conductive wires with the secondary grid lines and/or back electrodes. The conductive wires in the solar cell module will not drift or be insufficiently welded, and have relatively high photoelectric conversion efficiency.

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 the cells, such that the metal wire S constitutes a front conductive wire 32A. Alternatively, a first metal wire S extends reciprocally between the front surfaces of the cells, and a second metal wire S extends reciprocally between the back surfaces of the cells, such that the first metal wire S constitutes a front conductive wire 32A, and the second metal wire S constitutes a back conductive wire 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 a front conductive wire 32A, and part thereof which extends on the back surface of the second cell 31 constitutes a back conductive wire 32B. In the present disclosure, unless specified otherwise, the conductive wire 32 can be understood as the front conductive wire 32A, the back conductive wire 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, a plurality of conductive wires 32 of the cells 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 line and the back electrode, 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 conductive wires made of the silver paste, and the efficiency of photoelectric conversion 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 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, a secondary grid line 312 (a front secondary grid line 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 a back electrode 314 disposed on the back electric field 313. In the present disclosure, it can be understood that the back electrode 314 may be a back electrode of a traditional cell, for example, printed by the silver paste, or may be a back secondary grid line 312B similar to the secondary grid line 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 line 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 a front conductive wire of the first cell 31A and a back conductive wire of the second cell 31B. The metal wire S is electrically connected with the secondary grid line of the first cell 31A (for example, being welded or bounded by a conductive adhesive) , and electrically connected with the back electrode of the second cell 31B.

In some embodiments, the metal wire extends reciprocally between the first cell 31A and the second cell 31B for 10 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. Of course, the metal wire in the present disclosure is not limited to a single one –there may be multiple metal wires, or multiple metal wires are winded alone. In this embodiment, the number of the conductive wires is increased, compared with the traditional cell, such that the distance between the secondary grid line and the conductive wire 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.

More preferably, as shown in Fig. 4, the metal wire S includes a metal wire body 321 and a welding layer 322 coating the outer surface of the metal wire body. The metal wire is welded with the secondary grid lines and/or the back electrodes by the welding layer, such that 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. Of course, the electrical connection of the metal with the cell substrate can be conducted during or before the laminating process of the solar cell module, and preference is given to the latter.

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； and the conductive wires 32 include a metal wire body 321 and a welding layer 322 coating the metal wire body 321, i.e. the metal wire S consists of the metal wire body 321 and the welding layer 322 coating the metal wire body 321. In the embodiments of the present disclosure, unless specified otherwise, the metal wire represents the metal wire S which extends reciprocally on the cells to form the conductive wires 32.

In some embodiments, preferably, the metal wire body 321 is a copper wire. Of course, the metal wire S can be a copper wire, too. In other words, the metal wire does not include the welding layer 322, but the present disclosure does not limited thereto. For example, the metal wire body 321 can be an aluminum wire. Preferably, the metal wire S has a circular cross section, such that more sunlight can reach the cell substrate to further improve the photoelectric conversion efficiency.

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 a front conductive wire of the first cell 31A and a front conductive wire of the second cell 31B. In such a way, the first cell 31A and the second cell are connected in parallel. Of course, it can be understood that preferably the back electrode of the first cell 31A and the back electrode of the second cell 31B can be connected via a back conductive wire constituted by another metal wire which extends reciprocally. Alternatively, the back electrode of the first cell 31A and the back electrode of the second cell 31B can be connected in a traditional manner.

According to an embodiment of the present disclosure, the adjacent cells 31 are connected by a plurality of conductive wires 32 constituted by the metal wire which extends between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31.

Alternatively, the metal wire breaks off at a turn after being connected with the cells 31.

Preferably, the short grid lines 33 are connected with the edge secondary grid line 3121 closest to the middle secondary grid lines 3122.

In some other specific embodiments of the present disclosure, the short grid lines 33 are connected with the conductive wires 32. Preferably, the short grid lines 33 and the metal wire at the front surface of the cell 31 are connected at a turn.

According to an embodiment of the present disclosure, the short grid lines 33 are perpendicular to the secondary grid lines 312. The short grid lines 33 are, preferably, electrically connected with bended parts (ends proximate to the edges) of the conductive wires 32 on the shiny surface of the cell 31. An extra welding point can be added to decrease the probability of breaking the welding portion at the edges, and to further enhance the binding force of the metal wire and the cell. The connection with at the turn herein can be understood that the short grid lines 33 have intersection points with the turns, i.e. the short grid lines 33 do not terminate at the turns. More preferably, at least one short grid line 33 is disposed corresponding with each bended part. Of course, the short gird lines 33 can be connected with other parts of the conductive wires 32, for example, arc segments.

Since the distance between the bended parts of the conductive wires 32 and the edges of the cell 31 is usually short, the short grid lines 33 have a length of 1 to 10mm, preferably 2.4 to 7mm, a width of 0.05 to 0.5mm, and a thickness of 0.01 to 0.02mm. There are 3 to 40, preferably 6 to 20 short grid lines.

The short grid lines 33 can be disposed in the same manner as the secondary grid lines 312 on the shiny surface of the cell 31. For example, the short grid lines 33 can be printed along with the secondary grid lines 312 by silk-screen printing at the same screen plate (which can be made of silver paste) as the front secondary grid lines 3121.

In some preferable embodiments of the present disclosure, the secondary grid lines 312 have 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.

Alternatively, the metal wire breaks off at a turn after being connected with the cell 31. The metal wire breaks off at the turn after being welded with the cell 31 to form multiple independent conductive wires 32. The metal wire breaks off at the turn after being welded with the cell 31 to separate the multiple conductive wires 32, which can decrease the stress between the cells and peeling strength at the joints of the metal wire and the cell, and further improve the photoelectric conversion efficiency of the solar cell array 30.

In some specific embodiments of the present disclosure, in a row of the cells 31, the adjacent cells are connected by a metal wire that extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell and constitutes the conductive wire 32. Alternatively, a plurality of cells 31 are arranged in an n×m matrix form, and 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, in which n represents a column, m represents a row, and m-1≥a≥1.

Alternatively, in two adjacent rows of cells 31, the metal wire extends reciprocally between a surface of a cell 31 at an end of the a^th row and a surface of a 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.

Preferably, in the same row of 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. 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.

In other words, the solar cell array 30 according to the embodiment of the present disclosure is arranged in an n×m matrix form by a plurality of cells 31. Specifically, in the solar cell array 30, there are multiple cells 31, and the cells are arranged in the n×m matrix form. In a row of cells, the conductive wire 32 extends from a surface of a first cell 31, and is electrically connected with a surface of a second cell 31 adjacent to the first cell 31, to connect the cells 31 in the same row； in two adjacent rows of cells, the conductive wire 32 extends from a surface of a cell 31 in a a^th row and is electrically connected with a surface of a cell in a (a+1) ^th row, to connect the two adjacent rows of cells 31, in which n represents a column, m represents a row, and m-1≥a≥1.

N can range from 2 to 30, m ranging from 2 to 18. Preferably, multiple cells 31 are arranged in a 12×6 or 10×6 matrix form, i.e. 10 or 12 cells in a row, six rows in total. According to the preferable embodiment, the cells 31 in two adjacent rows are directly connected by the conductive wires without using the bus bars, which decreases the number of the bus bars, shortens the connection distance, and reduces the resistance, so as to obtain higher electricity generation performance of the solar cell module.

Preferably, in the two adjacent rows of cells 31, the conductive wire extends from a surface of a cell 31 at an end of a a^th row and is electrically connected with a surface of a cell at an end of a (a+1) ^th row.

According to a preferable embodiment of the present disclosure, a welding layer is disposed at a position where the conductive wires 32 are in contact with the secondary grid lines 312 and/or the back electrodes 314 of the cell 31. More preferably, the welding layer is disposed at the positions where the conductive wires 32 are in contact with the secondary grid lines 312 of the cell 31 and in contact with the back electrodes 314 thereof respectively. The welding layer can be only applied to the secondary grid lines 312 and back electrodes 314, or can also be applied to the conductive wires 32. The welding layer may be a metal with a lower melting point or an 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 conductive wires 32 and the secondary grid lines 312 and/or the back electrodes 314 of the cell, and to render the solar cell module higher photoelectric conversion efficiency.

In the cell array 30, the ratio of the thickness of the welding layer and the diameter of the metal wire is (0.02-0.5) : 1.

In the present disclosure, when there is a welding layer disposed at a position where the conductive wires 32 are in contact with the secondary grid lines 312 and/or the back electrodes 314 of the cell 31, the conductive wires 32 can be a metal wire. The metal wire may be conventional in the art, for example, a copper wire.

In an embodiment, the conductive wires (including the front conductive wires 32A and back conductive wires 32B) include a metal wire and an alloy layer with a low melting point coating the metal wire. The alloy layer may coat the metal wire completely or partially. When the alloy layer coats the metal wire partially, the alloy layer is, preferably, formed at a position where the alloy layer is welded with the secondary grid lines 312 and/or the back electrodes 314 of the cell 31. When the alloy layer coats the metal wire completely, the alloy layer can coat the periphery of the metal wire in a circular manner. The thickness of the alloy layer can fall into a relatively wide range. Preferably, the alloy layer has a thickness of 1 to 100μm, more preferably, 1 to 30μm. 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 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 a conductive wire extending from the left side of the first cell 31 in the first row, and a second bus bar is connected with a 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 cells 31 in the second row to the sixth row.

In some specific embodiments of the present disclosure, a 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 wire can be first bounded or welded with the secondary grid lines and the back electrode 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.

Specifically, the solar module 100 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. The cell array 30 includes a plurality of cells 31, and adjacent cells 31 are connected by the plurality of conductive wires 32. At least two conductive wires 32 are constituted by the metal wire S which extends reciprocally between surfaces of adjacent cells. The conductive wires 32 are welded with the secondary grid lines. The front adhesive layer 20 contacts with the conductive wires 32 directly and fills between the adjacent conductive wires 32.

That’s to say, the solar cell module 100 according to 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 cell array 30 includes a plurality of cells 31 and conductive wires 32 for connecting the plurality of cells 31. The conductive wires are constituted by the metal wire S which extends reciprocally between surfaces of two adjacent cells 31.

The conductive wires 32 are electrically connected with the cells 31, in which the front adhesive layer 20 on the cells 31 contacts with the conductive wires 32 directly and fills between the adjacent conductive wires 32, such that the front adhesive layer 20 can fix the conductive wires 32, and separate the conductive wires 32 from air and moisture from the outside world, so as to prevent the conductive wires 32 from oxidation and to guarantee the photoelectric conversion efficiency.

Thus, in the solar cell module 100 according to embodiments of the present disclosure, the conductive wires 32 constituted by the metal wire S which extends reciprocally replace traditional primary grid lines and solder strips, so as to reduce the cost. The metal wire S extends reciprocally to decrease the number of free ends of the metal wire S and to save the space for arranging the metal wire S, i.e. without being limited by the space. The number of the conductive wires 32 constituted by the metal wire which extends reciprocally may be increased considerably, which is easy to manufacture, and thus is suitable for mass production. The front adhesive layer 20 contacts with the conductive wires 32 directly and fills between the adjacent conductive wires 32, which can effectively isolate the conductive wires from air and moisture to prevent the conductive wires 32 from oxidation to guarantee the photoelectric conversion efficiency.

In some specific embodiments of the present disclosure, the metal wire S extends reciprocally between a front surface of a first cell and a back surface of a second cell adjacent to the first cell； the front adhesive layer 20 contacts with the conductive wires on the front surface of the first cell 31 directly and fills between the adjacent conductive wires 32 on the front surface of the first cell 31；the back adhesive layer 40 contacts with the conductive wires 32 on the back surface of the second cell 31 directly and fills between the adjacent conductive wires 32 on the back surface of the second cell 31.

In other words, in the present disclosure, the two adjacent cells 31 are connected by the metal wire S. In the two adjacent cells 31, the front surface of the first cell 31 is connected with the metal wire S, and the back surface of the second cell 31 is connected with the metal wire S.

The front adhesive layer 20 on the first cell 31 whose front surface is connected with the metal wire S is in direct contact with the metal wire S on the front surface of the first cell 31 and fills between the adjacent conductive wires 32. The back adhesive layer 40 on the second cell 31 whose back surface is connected with the metal wire S is in direct contact with the metal wire S on the back surface of the second cell 31 and fills between the adjacent conductive wires 32 (as shown in Fig. 2) .

Consequently, in the solar cell module 100 according to the present disclosure, not only the front adhesive layer 20 can separate the conductive wires 32 on the front surfaces of part of the cells 31 from the outside world, but also the back adhesive layer 40 can separate the conductive wires 32 on the back surfaces of part of the cells 31 from the outside world, so as to further guarantee the photoelectric conversion efficiency of the solar cell module 100.

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:

Forming a plurality of conductive wires 32 by a metal wire which extends reciprocally a surface of a first cell 31 of a plurality of cells 31 and a surface of a second cell 31 thereof, such that the adjacent cells 31 are connected by the plurality of conductive wires 32 to constitute a cell array 30, wherein the plurality of cells 31 are arranged in an n×m matrix form； in a row of cells 31, a 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 31 in a (a+1) ^th row to obtain the cell array 30, n representing a column, m representing a row and m-1≥a≥1, a secondary grid line 312 and a short grid line 33 being disposed on a front surface of the cell 31, the secondary grid line 312 including a middle secondary grid line 3122 intersected with the conductive wire 32 and an edge secondary grid line 3121 non-intersected with the conductive wire 32, the short grid line 33 being connected with the edge secondary grid line 3121, and being connected with the conductive wire 32 or at least one middle secondary grid line 3122, the metal wire being coated with a welding layer by which the metal wire is welded with the middle secondary grid line 3122；

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, 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 laminating them to obtain the solar cell module 100.

Specifically, the short grid lines 33 can be manufactured in the same way as the secondary grid lines 312 on the shiny surface of the cell 31, for example, screen printed in conjunction with the secondary grid lines and with the help of the same screen printing plate as the front secondary gird lines 3121, and the short grid lines 33 may be made of silver paste.

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 31 and a second cell 31 are prepared. As shown in Fig. 9, a front surface of the first cell 31 is connected with a metal wire, and a back surface of the second cell 31 is connected with the metal wire, such that the cell array 30 is formed. Fig. 9 shows two cells 31. 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 31 and the back surface of the second cell 31 adjacent to the first cell 31, i.e. connecting a secondary grid line of the first cell 31 with a back electrode of the second cell 31 by the metal wire. The metal wire extends reciprocally under strain from two clips at two ends thereof. The metal wire can be winded only with the help of two clips, which saves the clips considerably and then reduces the assembling space.

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 a front surface of the cell 31 faces the front adhesive layer 20, a back surface thereof facing the back adhesive layer 40, and laminating them 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.

The front adhesive layer 20 is disposed in direct contact with the conductive wires 32. In the process of laminating, the front adhesive layer 20 melts and fills the gaps between adjacent conductive wires 32. The back adhesive layer 40 is disposed in direct contact with the conductive wires 32. In the process of laminating, the back adhesive layer 40 melts and fills the gaps between adjacent conductive wires 32.

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 a metal wire S

An alloy layer of Sn40％-Bi55％-Pb5％ (melting point: 125℃) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.04mm², and the alloy layer has a thickness of 16μm. Hence, the metal wire S is obtained.

(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 1650×1000×3mm 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) on its front surface, 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.

The short grid lines are printed at an edge of a side of the front surface of the cell by a newly designed secondary grid mesh at the same time of printing the secondary grid lines. The short grid lines are perpendicular to the secondary grid lines, and connected with the outermost secondary grid line at the edge. The short grid line printed has a length of 5.1mm and a width of 0.2mm. There are eight short grid lines.

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.

60 cells 31 are arranged in a matrix form (six rows and ten columns) . In two adjacent cells 31 in a row, a 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 under strain from two clips at two ends thereof, and is intersected with the short gird lines at the turns formed by reciprocal extension, so as to form 15 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 9.9mm. 10 cells are connected in series into a row, and identical metal wires are arranged in the above way to obtain the same conductive wires, such that six rows of the cells of such kind are connected in series into a cell array. 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 20, such that the front adhesive layer 20 contacts with the conductive wires 32 directly； and the shady surface of the cell 31 faces the back adhesive layer 40, and finally they are laminated in a laminator, in which the front adhesive layer 20 fills between adjacent conductive wires 32. In such way, a solar cell module A1 is obtained.

Comparison example 1

The difference of Comparison example 1 and Example 1 lies in that a conventional grid mesh is employed, and the short grid lines are not printed at the same time of printing the secondary grid lines. In such a way, a solar cell module D1 as shown in Fig. 12 is obtained.

Comparison example 2

The differences between Comparison example 2 and Comparison example 1 lie in that the cells are arranged in a matrix form； 15 metal wires connected in series are pasted at a transparent adhesive layer, and the metal wires are attached to the solar 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, and a first transparent adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a second transparent adhesive layer, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down. Thus, a solar cell module D2 is obtained.

Comparison example 3

The difference of Comparison example 3 and Example 1 lies in that the cells 31 are arranged in a matrix form, and in two adjacent cells 31, each of the fifteen parallel metal wires, by wiredrawing as shown in Fig. 13, is strained by the clips 34 at the ends thereof to flatten the cell. the strain from the clips is 2N, such that each of the fifteen parallel metal wires is welded with a secondary grid line on a front surface of a first cell 31 respectively, and welded with a back electrode on a back surface of a second cell 31. The distance between of the adjacent conductive wires 32C in parallel to each other is 9.9mm. In such a way, a solar cell module D3 is obtained.

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 metal wire S

An alloy layer of Sn40％-Bi55％-Pb5％ (melting point: 125℃) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.03mm², and the alloy layer has a thickness of 10μm. Hence, the metal wire S is obtained.

(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 1650×1000×3mm 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) at its shiny surface, 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 short grid lines are printed at an edge of a side of the front surface of the cell by a newly designed secondary grid mesh at the same time of printing the secondary grid lines. The short grid lines are perpendicular to the secondary grid lines, and connected with the outermost secondary grid line at the edge. The short grid line printed has a length of 3.4mm and a width of 0.1mm. There are ten short grid lines.

60 cells 31 are arranged in a matrix form (six rows and ten columns) . In two adjacent cells 31 in a row, a 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 under strain from two clips at two ends thereof, and is intersected with the short gird lines at the turns formed by reciprocal extension, 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. 10 cells are connected in series into a row, and identical metal wires are arranged in the above way to obtain the same conductive wires, such that six rows of the cells of such kind are connected in series into a cell array. 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 20, such that the front adhesive layer 20 contacts with the conductive wires 32 directly； and the shady surface of the cell 31 faces the back adhesive layer 40, and finally they are laminated in a laminator, in which the front adhesive layer 20 fills between adjacent conductive wires 32. In such way, a solar cell module A2 is obtained.

Example 3

The solar cell module is manufactured according to the method in Example 2, but the difference compared with Example 2 lies in that the short grid lines are printed at an edge of a side of the front surface of the cell by a newly designed secondary grid mesh at the same time of printing the secondary grid lines. The short grid lines are perpendicular to the secondary grid lines, and connected with the outermost secondary grid line at the edge. The short grid line printed has a length of 5.1mm and a width of 0.15mm. There are ten short grid lines. The turn formed by reciprocal extension is located between the second and the third short grid lines. The short grid lines are intersected with the third secondary grid line.

Example 4

The solar cell module is manufactured according to the method in Example 2, but the difference compared with Example 2 lies in that after being welded the secondary grid lines, the metal wire cuts the arc segments at the turns to form separate and parallel 20 metal wires. The distance between adjacent parallel primary grid lines is 7mm. In such a way, a solar cell module A4 is obtained.

Example 5

The solar cell module is manufactured according to the method in Example 1, but the difference compared with Example 1 lies in that the alloy layer is 50％Sn-48％Bi-1.5％Ag-0.5％Cu (melting point: 160℃) . In such a way, a solar cell module A5 is obtained.

Example 6

The solar cell module is manufactured according to the method in Example 1, but the difference compared with Example 1 lies in that the alloy layer is 58％Bi-42％Sn. In such a way, a solar cell module A6 is obtained.

Example 7

The solar cell module is manufactured according to the method in Example 1, but the difference compared with Example 1 lies in that the alloy layer is 65％Sn-20％Bi-10％Pb-5％Zn. In such a way, a solar cell module A7 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 (STC) : 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.

Testing example 2

(1) Welding a metal wire onto a surface of a cell, the metal wire being in perpendicular to secondary grid lines of the cell；

(2) Placing the cell horizontally at a testing position of a tensile tester, and pressing blocks on the cell, in which the pressing blocks are disposed at two sides of the metal wire, such that the cell will not be pulled up during the test；

(3) Clamping the metal wire at a pull ring of a tension meter that forms an angle of 45° with the cell；

(4) Actuating the tension meter, such that the tension meter moves uniformly along a vertical direction, pulls up the metal wire from the surface of the cell and records the pull data tested, in which the data is averaged to obtain the pull data of the metal wire. The testing result is shown in Table 2.

Table 2

Module	A1	D1	D2	D3	A2	A3	A4	A5	A6	A7
Module	A1	D1	D2	D3	A2	A3	A4	A5	A6	A7	Tensile force (N)	0.45	0.38	0.25	0.26	0.34	0.33	0.39	0.48	0.43	0.37

It can be indicated from Table 2 that for the solar cell module according to the embodiments of the present disclosure, greater tensile force is needed to pull the metal wire away from the upper gall of the cell, which proves stronger stability of connection between the metal wire and the cell in the solar cell module.

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, “a plurality 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 arranged in an n×m matrix form, wherein

in a row of cells, adjacent cells are connected by a plurality of conductive wires, at least two conductive wires constituted by a metal wire which extends reciprocally between surfaces of adjacent cells；

in two adjacent rows of cells, a cell in a a^th row and a cell in a (a+1) ^th row are connected by the plurality of conductive wires, and at least two conductive wires are constituted by a metal wire extending reciprocally between a surface of a cell in a a^th row and a surface of a cell in a (a+1) ^th row, n representing a column, m representing a row and m-1≥a≥1；

a secondary grid line and a short grid line are disposed on a front surface of the cell, the secondary grid line includes a middle secondary grid line intersected with the conductive wire and an edge secondary grid line non-intersected with the conductive wire, the short grid line being connected with the edge secondary grid line, and being connected with the conductive wire or at least one middle secondary grid line, the metal wire coated with a welding layer by which the metal wire is welded with the middle secondary grid line.
The solar cell array according to claim 1, 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 2, 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 claim 2, 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 back surface of a cell at an end of the a^th row and a front 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 1 to 4, 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 any one of claims 1 to 5, wherein the metal wire extends reciprocally for 10 to 60 times.
The solar cell array according to any one of claims 1 to 6, wherein a distance between two adjacent conductive wires ranges from 2.5mm to 15mm.
The solar cell array according to any one of claims 1 to 7, wherein the two adjacent conductive wires form a U-shape structure or a V-shape structure.
The solar cell array according to any one of claims 1 to 8, wherein the metal wire is a copper wire.
The solar cell array according to any one of claims 1 to 9, wherein the metal wire has a circular cross section.
The solar cell array according to any one of claims 1 to 10, wherein the metal wire extends reciprocally under strain, before being connected with the cells.
The solar cell array according to any one of claims 1 to 11, wherein the welding layer is an alloy.
The solar cell array according to claim 12, wherein the welding layer contains Sn, and at least one of Bi, In, Ag, Sb, Pb and Zn.
The solar cell array according to claim 12, wherein the welding layer contains Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn.
The solar cell array according to any one of claims 1 to 14, wherein a ratio of a thickness of the welding layer and a diameter of the metal wire is (0.02-0.5) : 1.
The solar cell array according to any one of claims 1 to 15, wherein the short grid line is perpendicular to the secondary grid line.
The solar cell array according to any one of claims 1 to 16, wherein the metal wire breaks off at a turn after being connected with the cells.
The solar cell array according to any one of claims 1 to 17, wherein the short grid line has a width of 0.05 to 0.5mm； 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 1 to 18, wherein a binding force between the metal wire and the secondary grid lines ranges from 0.1N to 0.8N.
The solar cell array according to claim 19, wherein the binding force between the metal wire and the secondary grid lines ranges from 0.2N to 0.6N.
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 20.
The solar cell module according to claim 21, wherein the front adhesive layer contacts with the conductive wires directly and fills between adjacent conductive wires.
The solar cell module according to claim 21, 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 front adhesive layer contacts with the conductive wires on the front surface of the first cell directly and fills between the adjacent conductive wires on the front surface of the first cell； the back adhesive layer contacts with the conductive wires on the back surface of the second cell directly and fills between the adjacent conductive wires on the back surface of the second cell.
The solar cell module according to any one of claims 21 to 23, wherein the cell has a dimension of 156mm×156mm； and the solar cell module has a series resistance of 380 to 440 mΩ per 60 cells.
The solar cell module according to any one of claims 21 to 23, wherein the cell has a dimension of 156mm×156mm； and the solar cell module has an open-circuit voltage of 37.5-38.5V per 60 cells, and a short-circuit current 8.9-9.4A.
The solar cell module according to any one of claims 21 to 23, wherein the solar cell module has a fill factor of 0.79 to 0.82.
The solar cell module according to any one of claims 21 to 23, wherein the cell has a dimension of 156mm×156mm； and the solar cell module has a working voltage of 31.5-32V per 60 cells, and a working current of 8.4-8.6A.
The solar cell module according to any one of claims 21 to 23, wherein the cell has a dimension of 156mm×156mm； and 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 a solar cell module, comprising:

forming a plurality of conductive wires by a metal wire which extends reciprocally a surface of a first cell of a plurality of cells and a surface of a second cell thereof, such that the adjacent cells are connected by the plurality of conductive wires to constitute a cell array, wherein the plurality of cells are arranged in an n×m matrix form； in a row of cells, a 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 to obtain the cell array, n representing a column, m representing a row and m-1≥a≥1, a secondary grid line and a short grid line being disposed on a front surface of the cell, the secondary grid line including a middle secondary grid line intersected with the conductive wire and an edge secondary grid line non-intersected with the conductive wire, the short grid line being connected with the edge secondary grid line, and being connected with the conductive wire or at least one middle secondary grid line, the metal wire being coated with a welding layer by which the metal wire is welded with the middle secondary grid line；

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 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 method according to claim 30, 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 method according to claim 30, 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 back surface of a cell at an end of the a^th row and a front surface of a cell at an end of the (a+1) ^th row, to connect the two adjacent rows of cells in series.
The method according to any one of claims 29 to 32, 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 method according to any one of claims 29 to 33, wherein the metal wire extends reciprocally for 10 to 60 times.
The method according to any one of claims 29 to 34, wherein a distance between two adjacent conductive wires ranges from 2.5mm to 15mm.
The method according to any one of claims 29 to 35, wherein the metal wire is a copper wire.
The method according to any one of claims 29 to 36, wherein the metal wire extends reciprocally under strain, before being connected with the cells.
The method according to any one of claims 29 to 37, wherein the metal wire is welded with the secondary grid line and the short grip line by the welding layer coating the metal wire.