US20160126389A1 - Solar cell unit, solar cell array, solar cell module and manufacturing method thereof

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Abstract

Description

Claims

US20160126389A1

Publication number: US20160126389A1
Application number: US14/738,516
Authority: US
Inventors: Zhiqiang Zhao; Zhanfeng Jiang; Long He
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2014-10-31
Filing date: 2015-06-12
Publication date: 2016-05-05
Also published as: US20160126388A1; US10529868B2; US20160126363A1; US20160126362A1; US20160126364A1; US10193003B2; US20160126361A1; US10069019B2; US20160126365A1; US20160126372A1; US10381493B2; US20160126366A1; US20190051764A9; US20160126390A1; US20160126373A1

In one aspect, a solar cell unit comprises a cell. The cell includes a cell substrate and a plurality of secondary grid lines disposed on a front surface of the cell substrate. The solar cell unit also comprises a plurality of conductive wires spaced apart from each other. The plurality of conductive wires intersects and is connected with the secondary grid lines. At least one secondary grid line has at least one gap located between adjacent conductive wires.

The present application claims priority to the following 41 Chinese applications, the entireties of all of which are hereby incorporated by reference.

- 1. Chinese Patent Application No. 201410608576.6, filed Oct. 31, 2014;
- 2. Chinese Patent Application No. 201410606607.4, filed Oct. 31, 2014;
- 3. Chinese Patent Application No. 201410606601.7, filed Oct. 31, 2014;
- 4. Chinese Patent Application No. 201410606675.0, filed Oct. 31, 2014;
- 5. Chinese Patent Application No. 201410608579.X, filed Oct. 31, 2014;
- 6. Chinese Patent Application No. 201410608577.0, filed Oct. 31, 2014;
- 7. Chinese Patent Application No. 201410608580.2, filed Oct. 31, 2014;
- 8. Chinese Patent Application No. 201410606700.5, filed Oct. 31, 2014;
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- 36. Chinese Patent Application No. 201510217616.9, filed Apr. 3, 2015;
- 37. Chinese Patent Application No. 201520278149.6, filed Apr. 3, 2015;
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The present application is relevant to the following 10 U.S. applications, filed concurrently with the present application, the entireties of which are hereby incorporated by reference.
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-23), entitled “Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-24), entitled “Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-26), entitled “Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-28), entitled “Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-29), entitled “Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-32), entitled “Solar Cell Unit, Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-33), entitled “Solar Cell Unit, Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-35), entitled “Solar Cell Unit, Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-36), entitled “Solar Cell Unit, Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______; and
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-44), entitled “Method For Manufacturing Solar Cell Module,” filed ______.

FIELD

The present disclosure relates to the field of solar cells, and more particularly, to solar cell units, solar cell arrays, solar cell modules and a manufacturing methods thereof.

BACKGROUND

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

SUMMARY

In one aspect, a solar cell unit comprises a cell. The cell includes a cell substrate and a plurality of secondary grid lines disposed on a front surface of the cell substrate. The solar cell unit also comprises a plurality of conductive wires spaced apart from each other. The plurality of conductive wires intersects and is connected with the secondary grid lines. At least one secondary grid line has at least one gap located between adjacent conductive wires.
In another aspect, a method for manufacturing a solar cell module comprises providing a cell. The cell includes a cell substrate and a plurality of secondary grid lines disposed on a front surface of the cell substrate. The method also comprises intersecting and connecting conductive wires comprising a metal wire with the secondary grid lines to obtain a solar cell unit. At least one secondary grid line has at least one gap located between adjacent conductive wires. The method further comprises superposing an upper cover plate, a front adhesive layer, the solar cell unit, a back adhesive layer and a back plate in sequence. A front surface of the cell faces the front adhesive layer. A back surface thereof faces the back adhesive layer. The method also comprises laminating the superposed layers to obtain the solar cell module.

BRIEF DESCRIPTION OF THE DRAWINGS

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

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

FIG. 2B is a sectional view of a solar cell array according to another embodiment of the present disclosure;

FIG. 2C is a sectional view of a solar cell array according to yet another embodiment of the present disclosure;

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

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

FIG. 4B is a schematic diagram of a metal wire for forming a conductive wire according to another embodiment of the present disclosure;

FIG. 4C is a schematic diagram of a metal wire for forming a conductive wire according to yet another embodiment of the present disclosure;

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

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

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

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

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

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

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

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

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

FIG. 13 is a schematic diagram of a secondary grid line of a solar cell according to an embodiment of the present disclosure;

FIG. 14 is a schematic diagram of a secondary grid line of a solar cell according to another embodiment of the present disclosure.

FIG. 15 is a schematic diagram of a back welding portion of a solar cell unit according to an embodiment of the present disclosure.

REFERENCE NUMERALS

- 100 cell module
- 10 upper cover plate
- 20 front adhesive layer
- 30 cell array
- 31 cell
- 31A first cell
- 31B second cell
- 311 cell substrate
- 312 secondary grid line
- 312A front secondary grid line
- 312B back secondary grid line
- 3121 edge secondary grid line
- 3122 middle secondary grid line
- 3123 welding portion
- 3124 gap
- 313 back electric field
- 314 back electrode
- 32 conductive wire
- 32A front conductive wire
- 32B back conductive wire
- 321 metal wire body
- 322 connection material layer
- 33 short grid line
- 40 back adhesive layer
- 50 lower cover plate
- 51 reflective coating
- 60 U-shape frame
- 70 junction box
- 80 mounting block

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.
In prior art, the front surface of the solar cell is usually provided with the primary grid lines and the secondary grid lines to output the current generated by the photoelectric effect or chemistry effect. In order to improve the efficiency of the solar cells, solar cell manufacturers conducted extensive researches on how to increase the number of the primary grid lines. In prior art, the number of primary grid lines has been successfully increased from two to three, or even five.
However, in prior art, the primary grid lines are formed by printing the paste containing expensive silver, so the manufacturing cost is very high, and the increase of the silver primary grid lines absolutely causes an increase in cost. Moreover, the current silver primary grid line has a great width (for example, up to over 2 mm), such that the increase of the silver primary grid lines will enlarge the shaded area, and make the photoelectric conversion efficiency low.
Consequently, in order to lower the cost and reduce the shaded area, in prior art, the silver primary grid lines printed on the cells are replaced with metal wires, such as copper wires which serve as the primary grid lines to output the current. Since the silver primary grid lines are no longer used, the cost can be reduced considerably; the diameter of the copper wire is relatively small, so the shaded area can be decreased. Thus, the number of the primary grid lines can be further increased up to 10. This kind of cell may be called a cell with multiple primary grid lines, in which the metal wire replaces the silver primary grid lines and welding strips in the traditional solar cell.
After extensive research, the inventors of the present disclosure finds if a cell is manufacture in a way that multiple parallel metal wires are drawn simultaneously, cut off, and then welded to the cell simultaneously, due to limitations 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 strained to flatten the cell (a test proves that the minimum strain is at least 2 N for a copper wire with a diameter of 0.2 mm). 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 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 free ends there are, 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 156 mm×156 mm. 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 difficult to control and weld multiple metal wires simultaneously in actual production, so the number of the conductive wires is limited, usually at most about ten, 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 certain degree 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° C.). 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 circuits. The encapsulating material at present is EVA whose melting point is 70° C. to 80° C., 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, which is higher than 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. The metal wires are merely in contact with the secondary grid lines on the cells, i.e. the metal wires are only placed 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 relatively mature solar cell without primary grid lines.
Moreover, in solar cells, the secondary grid lines at the front surface of the cell are usually printed at the surface thereof by silver paste, and then sintered. The secondary grid lines of this structure are continuous and have an even dimension, which consumes more silver and results in higher cost.
Also, in solar cells without primary grid lines, since the conductive wires are metal wires of very small diameter, the welding of the conductive wires and the secondary grid lines is relatively difficult, which may cause insufficient welding and bad contact, thereby lowering the efficiency of the cells considerably and even resulting in failure thereof
The present disclosure seeks to solve at least one of the problems existing in the related art to at least some extent.
The solar cell with multiple primary grid lines provided in the present disclosure can be commercialized for mass production, and easy to manufacture with simple equipment, especially in low cost.
Thus, the present disclosure provides a solar cell unit that is easy to manufacture in low cost, and improves the photoelectric conversion efficiency.
Thus, the present disclosure provides a solar cell array that is easy to manufacture in low cost, and improves the photoelectric conversion efficiency.
Thus, the present disclosure provides a solar cell module with the above solar cell array, and 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 unit includes a cell consisting of a cell substrate and a plurality of secondary grid lines disposed on a front surface of the cell substrate; and a plurality of conductive wires spaced apart from each other, the plurality of conductive wires intersected and connected with the secondary grid lines, in which at least one secondary grid line has at least one gap located between adjacent conductive wires.
As for the solar cell unit according to embodiments of the present disclosure, at least one secondary grid line between adjacent conductive wires is provided with a gap, i.e. the at least one secondary grid line between the adjacent conductive wires breaks off in a position where there is no need to print silver paste or other materials for manufacturing the secondary grid lines, so as to save the amount of the material for manufacturing the secondary grid lines to lower the cost. Moreover, the inventor of the present disclosure finds out that the gaps disposed on the secondary grid lines will not affect the photoelectric conversion efficiency of the solar cell greatly. The solar cell unit according to the embodiments of the present disclosure still can obtain relatively high photoelectric conversion efficiency.
According to a second aspect of embodiments of the present disclosure, a solar cell array includes a plurality of solar cell units which are the solar cell units according to the above embodiments, and cells of the adjacent cell units are connected by the conductive wires.
According to a third aspect of embodiments of the present disclosure, a 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 fourth aspect of embodiments of the present disclosure, a method for manufacturing a solar cell module includes: providing a cell which includes a cell substrate and a plurality of secondary grid lines disposed on a front surface of the cell substrate; intersecting and connecting conductive wires constituted by a metal wire with the secondary grid lines to obtain a solar cell unit, in which at least one secondary grid line has at least one gap located between adjacent conductive wires; superposing an upper cover plate, a front adhesive layer, the solar cell unit, a back adhesive layer and a back plate in sequence, in which a front surface of the solar cell faces the front adhesive layer, a back surface thereof facing the back adhesive layer, and laminating them to obtain the solar cell module.
According to a fifth aspect of embodiments of the present disclosure, a solar cell unit includes a cell including a cell substrate, secondary grid lines spaced apart from each other in a front surface of the cell substrate, a back electric field disposed in a back surface of the cell substrate, and back welding portions spaced apart from each other in the back electric field, the back welding portions formed by applying silver paste or a tin alloy to the back field; front conductive wires constituted by a metal wire and electrically connected with the front secondary grid lines; and back conductive wires constituted by a metal wire and electrically connected with the back electric field via the back welding portions.
As for the solar cell unit according to embodiments of the present disclosure, the back electric field is disposed on the back surface of the cell substrate and back welding portions are disposed on the back electric field, such that the back conductive wires are welded with the back welding portions formed by silver paste or a tin alloy, which can improve connection performance of the back conductive wires and the back electric field considerably. Moreover, the solar cell unit in the present disclosure has simple production process-only screen printing design in need, and low cost.
According to a sixth aspect of embodiments of the present disclosure, a solar cell array includes a plurality of cell units which are the solar cell units according to the above embodiment, adjacent cells being connected by a metal wire which extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell, to form the front conductive wires and/or the back conductive wires.
According to a seventh aspect of embodiments of the present disclosure, a 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 an eighth aspect of embodiments of the present disclosure, a method for manufacturing a solar cell module includes: providing a cell which includes a cell substrate, secondary grid lines spaced apart from each other in a front surface of the cell substrate, a back electric field disposed in a back surface of the cell substrate, and back welding portions spaced apart from each other in the back electric field, the back welding portions formed by applying silver paste or a tin alloy to the back field; connecting front conductive wires constituted by a metal wire with the front secondary grid lines, and connecting back conductive wires constituted by a metal wire with the back secondary grid lines, to obtain a solar cell unit; superposing an upper cover plate, a front adhesive layer, the solar cell unit, a back adhesive layer and a back plate in sequence, in which a front surface of the solar cell unit faces the front adhesive layer, a back surface thereof facing the back adhesive layer, and laminating them to obtain the solar cell module.
According to a ninth aspect of embodiments of the present disclosure, a conductive wire of a solar cell unit is constituted by a metal wire whose cross section has a width gradually decreasing in a direction away from a cell.
The conductive wire according to embodiments of the present disclosure is constituted by the metal wire whose cross section has a width gradually decreasing in the direction away from the cell. That's to say, the area of the contact surface of the metal wire with the cell is larger than that of the surface of the metal wire opposite the contact surface. The conductive cross section of the metal wire with the cell is improved at the same time of reducing the shaded area, so as to improve the photoelectric conversion efficiency. Since the width of the cross section of the metal wire decreases gradually along the direction away from the cell, the side of the metal wire will have a certain tilting angle, i.e. the side surface is inclining. In such a case, the sunlight irradiating onto the tilting surface will be reflected to the front surface partially to raise light intensity, so as to improve the photoelectric conversion efficiency.
According to a tenth aspect of embodiments of the present disclosure, a solar cell unit includes a cell which consists of a cell substrate and a secondary grid line disposed on a front surface of the cell substrate; a conductive wire disposed on the front surface of the cell substrate, intersected and connected with the secondary grid line, and the conductive wire is a conductive wire for a solar cell unit according to the above embodiment.
According to an eleventh aspect of embodiments of the present disclosure, a solar cell array includes a plurality of solar cell units which are the solar cell units according to the above embodiments, and the adjacent cell units are connected by the metal wire.
According to a twelfth aspect of embodiments of the present disclosure, a 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 thirteenth aspect of embodiments of the present disclosure, a method for manufacturing a solar cell module includes: providing a solar cell array according to the above embodiments; superposing an upper cover plate, a front adhesive layer, the solar cell, a back adhesive layer and a back plate in sequence, in which a front surface of the solar cell unit faces the front adhesive layer, a back surface thereof facing the back adhesive layer, and laminating them to obtain the solar cell module.
According to a fourteenth aspect of embodiments of the present disclosure, a conductive wire of a solar cell unit is constituted by a metal wire whose height is H, and whose width is W, a ratio of the height H and the width W being greater than 1:1.
The conductive wire according to embodiments of the present disclosure is constituted by the metal wire whose height-width ratio is greater than 1, which can make full use of the space in the thickness direction of the cell, i.e. the space in the direction of the height of the conductive wires, so as to increase the cross section of the conductive wires. In other words, the conductive cross section can be enlarged with the same shaded area. When the shaded area is identical, the solar cell unit according to the embodiments of the present disclosure has larger conductive cross section of the conductive wires, so as to improve the performance of the cell.
According to a fifteenth aspect of embodiments of the present disclosure, a solar cell unit includes a cell which consists of a cell substrate and a secondary grid line disposed on a front surface of the cell substrate; a conductive wire disposed on the front surface of the cell substrate, intersected and connected with the secondary grid line, and the conductive wire is a conductive wire for a solar cell unit according to the above embodiments.
According to a sixteenth aspect of embodiments of the present disclosure, a solar cell array includes a plurality of solar cell units which are the solar cell units according to the above embodiments, and cells of the adjacent cell units are connected by the metal wire.
According to a seventeenth aspect of embodiments of the present disclosure, a 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 eighteenth aspect of embodiments of the present disclosure, a method for manufacturing a solar cell module includes: providing a solar cell array according to the above embodiments; superposing an upper cover plate, a front adhesive layer, the solar cell, a back adhesive layer and a back plate in sequence, in which a front surface of the solar cell unit faces the front adhesive layer, a back surface thereof facing the back adhesive layer, and laminating them to obtain the solar cell module.
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, referring to FIGS. 1-15, cell unit includes a cell 31 and conductive wires 32, so the conductive wires 32 can be called the conductive wires 32 of the cell unit.
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 front surface, and a back electric field 313 and back electrodes 314 on a back surface, or includes other equivalent solar cells of other types without any front electrode.
The cell unit, the cell 31 and the cell substrate 311 are used to illustrate the present disclosure, but shall not be construed to limit the present disclosure.
A solar cell array 30 is arranged by a plurality of cells, i.e. by a plurality of cells 31 connected by conductive wires 32.
In the solar cell array 30, a metal wire S constitutes the conductive wire 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 surfaces of the adjacent cells 31, or may be connected with a secondary grid line 312 of the cell 31, or may be connected with a secondary grid line 312 of a first cell 31 and a back electrode 314 of a second cell 31 adjacent to the first cell 31, or a part of the metal wire S is connected with the secondary grid line 312 and the other part of the metal wire S is connected with a back electrode 314 of the cell 31.
That's to say, the metal wire S can extend between front surfaces of adjacent cells 31, or 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 wire 32 may include a front conductive wire 32A extending on the front surface of the cell 31 and electrically connected with the secondary grid lien 312 of the cell 31, and a back conductive wire 32B extending on the back surface of the cell 31 and electrically connected with the back electrode 314 of the cell 31. Part of the metal wire S between the adjacent cells 31 can be called a connection conductive wire.
All the ranges disclosed in the present disclosure include endpoints, and can be individual or combined. It shall be understood that the terminals 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, 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 when the module is in operation, i.e. a surface on which light is incident, while “back surface” refers to a surface of the solar cell module back to the light when the module is in operation.
In the following, the solar cell unit will be described according to the embodiments of the present disclosure.
As shown in FIG. 1 to FIG. 13, the solar cell unit according to the embodiments of the present disclosure includes a cell 31 and conductive wires 32. Specifically, the cell 31 comprises a cell substrate 311 and secondary grid lines 312 disposed on a front surface of the cell substrate 311; the plurality of conductive wires 32 are spaced apart from each other, and intersected and connected with the secondary grid lines 312, in which at least one secondary grid line 312 has at least one gap located between adjacent conductive wires 32.
In other words, the solar cell according to the present disclosure is mainly formed with the cell 31 and conductive wires 32; the cell 31 is mainly constituted by the cell substrate 311 and secondary grid lines 312. In the present disclosure, the secondary grid lines 312 disposed on the front surface of the cell substrate 311 will be described in detail.
Specifically, a plurality of secondary grid lines 312 are disposed on the front surface of the cell substrate 311 and extend in one direction. A plurality of conductive wires 32 are disposed on the secondary grid lines 312 and extend in another direction. Each conductive wire 32 is intersected with the plurality of secondary grid lines 312 respectively; each secondary grid line 312 is intersected with the plurality of conductive wires 32 respectively.
That's to say, a plurality of conductive wires 32 and a plurality of secondary grid lines 312 can be intersected as a network, segments of multiple different secondary grid lines 312 are distributed between any two adjacent conductive wires 32, in which the segment of at least one secondary grid line 312 has one gap 3124, i.e. at least one of the multiple different secondary grid lines 312 between any two adjacent conductive wires 32 is formed with two segments.
As shown in FIG. 13, the secondary grid line 312 with the gap 3124 may have only one gap 3124, i.e. the part of the secondary grid line 312 is formed with two segments, or have multiple gaps 3124, i.e. the part of the secondary grid line 312 is formed with at least three segments.
It shall be noted that in the present disclosure, the secondary grid lines 312 are usually printed on the surface of the solar cell by silver paste, and sintered. The secondary grid lines 312 are provided with gaps 3124, i.e. being divided into multiple segments, such that the broken parts of the secondary grid lines 312 do not need silver paste printing, which can save the amount of silver.
Thus, as for the solar cell unit according to embodiments of the present disclosure, at least one secondary grid line 312 between adjacent conductive wires 32 is provided with a gap 3124, i.e. the at least one secondary grid line 312 between the adjacent conductive wires 32 breaks off in a position where there is no need to print silver paste or other materials for manufacturing the secondary grid lines 312, so as to save the amount of the material for manufacturing the secondary grid lines 312 to lower the cost.
According to an embodiment of the present disclosure, there are n conductive wires 32; and there is/are n−1 gap(s) 3124 in a single secondary grid line 312.
That's to say, supposing there are 15 conductive wires 32 arranged in parallel and intersected with the secondary grid lines 312 respectively. Any two adjacent conductive wires 32 divide each secondary grid line 312 into multiple segments. The fifteen conductive wires 32 divide each secondary grid line 312 into 16 segments, in which there are 14 segments of each secondary grid line 312 between the fifteen conductive wires 32, and each segment of each secondary grid line 312 is provided with one gap.
Thus, the secondary grid lines 312 of this structure can reduce the amount of raw materials to the greatest extent, so as to lower the cost.
Alternatively, in some embodiments of the present disclosure, a gap 3124 is disposed between two adjacent conductive wires 32.
That's to say, the secondary grid line 312 between two adjacent conductive wires 32 has a broken part, i.e. the secondary grid line 312 between two adjacent conductive wires 32 is formed with two segments. If only one gap 3124 is disposed between the two adjacent conductive wires 32, the process of manufacturing the secondary grid lines 312 can be reasonably controlled to simplify the production process at the same time of saving raw materials.
According to an embodiment of the present disclosure, the gap 3124 has a length of 0.2 to 5 mm in a longitudinal direction of the secondary grid line 312. Preferably, the gap 3124 has a length of 0.5 to 3 mm. Further, the gap 3124 is located in a middle position of the adjacent conductive wires 32.
Consequently, the length of the gap 3124 is designed as the above size, and the broken part of the secondary grid line 312 is located in a middle position of the adjacent conductive wires 32, such that the performance of the cell will not be greatly affected if the secondary grid lines break off, so as to save the raw materials, to guarantee the production operability, to simplify the production process, and control the photoelectric conversion efficiency of the cell in practical value.
Alternatively, according to an embodiment of the present disclosure, there are 20 to 200 secondary grid lines 312, preferably 30 to 120. A gap 3124 can be arranged at the part of each secondary grid line 312 between two adjacent conductive wires 32, to further reduce the materials for the secondary grid lines 312, thereby lowering the cost.
In some embodiments of the present disclosure, the conductive wires 32 are constituted by the metal wire body 321. In some embodiments, preferably, the metal wire body 321 is a copper wire, but the present disclosure is not limited thereto. For example, the metal wire body 321 can be an aluminum wire. Preferably, the metal wire body 321 has a circular cross section, such that more sunlight can irradiate the cell substrate to further improve the photoelectric conversion efficiency.
Further, the metal wire body 321 is coated with a welding layer at least at a part welded with the secondary grid lines 312, and the conductive wires 32 are welded with the secondary grid lines 312.
More preferably, as shown in FIG. 4A, the metal wire body 321 is coated with a connection material layer 322, such as a conductive adhesive layer or a welding layer. The metal wire is welded with the secondary grid line and/or the back electrode by the welding layer, such that it is convenient to electrically connect the metal wire body 321 with the secondary grid lines 312, 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 wire body 321 with the cell 31 can be conducted when or before the solar cell module is laminated, and preference is given to the latter.
In some other embodiments of the present disclosure, the secondary grid lines 312 are coated with a welding layer by which the conductive wires 32 are welded with the secondary grid lines 312.
That's to say, the conductive wires 32 and the secondary grid lines 312 can be welded by arranging the welding layer on the conductive wires 32 or on the secondary grid lines 312. When the welding layer is disposed on the secondary grid lines 312, only the welding point on the secondary grid lines 312 is usually provided with the welding layer, so as to guarantee the effect of welding the conductive wires 32 with the secondary grid lines 312, and to avoid the influence on the shaded area to guarantee the photoelectric conversion efficiency.
Alternatively, according to an embodiment of the present disclosure, the metal wire S extends reciprocally. Preferably, the metal wire S extends reciprocally under strain, before being connected with the secondary grid lines 312.
It shall be understood that the term “extending reciprocally” in the disclosure can be called “winding” which refers to that the metal wire S extends between the surfaces of the cells 31 along a reciprocal route.
Thus, in the cells according to the embodiments of the present disclosure, the conductive wires 32 are constituted by the metal wire S which extends reciprocally, and adjacent cells 31 are connected by the conductive wires 32. In such a case, the conductive wires 32 of the cell do not need expensive silver paste, and it is not necessary to use the welding strip to connect the cells, which is an easy manufacturing process. It is convenient to connect the metal wire S with the secondary grid lines 312 and back electrodes of the cells, so the cost of the cells is considerably reduced.
In some specific embodiments of the present disclosure, the secondary grid lines have a width in a welding position with the conductive wires 32 greater than in a non-welding position.
Specifically, as shown in FIG. 1, the secondary grid lines 312 are disposed on the front surface of the cell substrate 311 and extend in a direction. The conductive wires 32 are disposed on the secondary grid lines 312 and extend in another direction. The conductive wires 32 and the secondary grid lines 312 are welded at a portion where they are intersected. Usually, the conductive wires 32 are broader than the secondary grid lines 312, and the secondary grid lines 312 have a width in the welding portion with the conductive wire 32 greater than a width thereof in a non-welding portion.
That's to say, as shown in FIG. 13, the secondary grid lines 312 are broadened in a position where the secondary grid lines 312 are intersected with the conductive wires 32, and the broadened part of the secondary grid lines 312 is taken as a welding portion 3123 to be welded with the conductive wires 32. The welding portion 3123 of the secondary grid lines 312 is broaden to facilitate welding the secondary grid lines 312 with the conductive wires 32. Meanwhile, other parts of the secondary grid lines 312 remain the original width, or even reduce the width, which cannot only guarantee the welding effect of the secondary grid lines 312 and the conductive wires 32, but also reduce the shaded area.
Consequently, as for the solar cell according to the embodiments of the present disclosure, the portion where the secondary grid lines 312 are welded with the conductive wires 32 is widened, while other portions are relatively narrow, which makes it easier to weld the conductive wires 32 with the secondary grid lines 312, and to manufacture the welding portion, thereby reducing the cost. In such a case, the connection strength of the conductive wires 32 and the secondary grid lines 312 is enhanced, and the shaded area is decreased, which improves the photoelectric conversion efficiency of the solar cell.
According to an embodiment of the present disclosure, the secondary grid lines 312 have a width in the welding position greater than or equal to a diameter or width of the conductive wires 32.
In other words, the welding portion 3123 of the secondary grid lines 312 has a line width larger than or equal to that of the conductive wires 32. Thus, the portion where the secondary grid lines 312 are welded with the conductive wires 32 is configured to have a line width larger than or equal to that of the conductive wires 32, so as to further enhance the connection strength of the conductive wires 32 and the secondary grid lines 312, and to facilitate welding to reduce the cost.
In some other specific embodiments of the present disclosure, the short grid line 33 are disposed on the front surface of the cell substrate 311; the secondary grid lines 312 include middle secondary grid lines 3122 intersected with the conductive wires 32 and an edge secondary grid lines 3121 non-intersected with the conductive wires 33; the short grid lines 33 are connected with the edge secondary grid lines 3121, and connected with the conductive wires 32 or at least one middle secondary grid line 3122. Preferably, the short grid lines 33 are connected with the middle secondary grid lines 3122 closest to the edge secondary grid lines 3121.
As shown in FIG. 12, 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.
Thus, in the solar cell array 30 according to the embodiments of the present disclosure, the conductive wires 32 are constituted by the metal wire which extends reciprocally. The conductive wires 32 are constituted by the metal wire which extends reciprocally. The conductive wires 32 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 30.
As shown in FIG. 1 to FIG. 12, the solar cell unit according to the embodiments of the present application includes a cell 31, front conductive wires 32A and back conductive wires 32B.
Specifically, the cell 31 includes a cell substrate 311, secondary grid lines 312 spaced apart from each other in a front surface of the cell substrate 311, a back electric field 313 disposed in a back surface of the cell substrate 311, and back welding portions 314 spaced apart from each other in the back electric field 313, the back welding portions 314 formed by applying silver paste or a tin alloy to the back field 313; front conductive wires 32A constituted by a metal wire S and electrically connected with the front secondary grid lines 312A; and back conductive wires 32B constituted by a metal wire S and electrically connected with the back electric field 313 via the back welding portions 314.
In other words, the solar cell unit according to the present application is mainly formed with the cell 31 and conductive wires 32; the cell 31 is mainly constituted by the cell substrate 311 and secondary grid lines 312. In the present application, the front secondary grid lines 312A disposed on the front surface of the cell substrate 311 will be described in detail.
A plurality of front secondary grid lines 312A spaced from each other are disposed on the front surface of the cell substrate 311; front conductive wires 32A are disposed on the front surface of the cell substrate 311 and located on the front secondary grid lines 312A. The front conductive wires 32A are constituted by a metal wire S and electrically connected with the front secondary grid lines 312A.
The back electric field 313 is disposed on the back surface of the cell substrate 311; the back welding portions 314 are formed by applying silver paste or a tin alloy to the back field 313; the back conductive wires 32B are disposed on the back surface of the cell substrate 311 and located on the back welding portions 314, and are constituted by a metal wire S and electrically connected with the back welding portions 314.
It shall be noted that the solar cell unit mainly employs a structure of three conductive wires—three conductive wires printed by silver paste and sintered on the front and back surfaces respectively. The width of the conductive wire usually ranges from 1.4 mm to 2 mm.
In the solar cell unit without primary grid lines, the primary grid lines are usually replaced by multiple metal wires, and the secondary grid lines on the front surface are remained to connect the metal wires with the cells. The silver conductive wires on the back surface are replaced by the metal wires. However, the metal wires and the aluminum sintering layer on the back surface, i.e. the back electric fields, have poor welding performance. In the present application, if the back conductive wires 32B constituted by the metal wire S are directly welded with the back electric field 313, the welding performance tends to be poor, which affects the welding effect.
Thus, in the solar cell unit according to the embodiments of the present application, back electric fields 313 are disposed in the back surface of the cell substrate 311, and back welding portions 314 are disposed on the back electric fields 313. The front conductive wires 32A are welded with the back welding portions 314 formed by the silver paste or the tin alloy, which can improve the connection performance of the front conductive wires 32A and the back electric fields 313 considerably. Moreover, the solar cell unit in the present application has simple production process-only screen printing design in need, and low cost.
According to an embodiment of the present application, the tin alloy contains at least one of Cu, Ag, Pb, Bi, Zn, In, Fe and Ni, and Sn. In other words, the tin alloy is formed with Sn and at least one of Cu, Ag, Pb, Bi, Zn, In, Fe and Ni, such that the welding performance of the back welding portions 314 and the back conductive wires 32B will be better.
Alternatively, the back welding portions 314 are arranged into multiple rows spaced apart from each other; each row extends in a direction orthogonal to the back conductive wires 32B, and the back welding portions 314 in each row are spaced apart from each other. Thus, the back welding portions 314 of this structure can further reduce the amount of materials to reduce the cost.
Specifically, as shown in FIG. 1, the front secondary grid lines 312A on the cell substrate 311 extend in a direction from up to down, while the conductive wires 32A (including front conductive wires 32A and back conductive wires 32B) extend in a direction from left to right. Correspondingly, as shown in FIG. 3 and FIG. 15, the back welding portions 314 are arranged into multiple rows spaced apart from each other in the direction from left to right, and the back welding portions 314 in each row are orthogonal to the back conductive wires 32B respectively.
That's to say, in the embodiment of the present application, the structure of the back welding portions 314 is similar to that of the front secondary grid lines 312A. The back welding portions 314 can be understood as the back secondary grid lines 312B on the cell substrate 311. The back welding portions 314 only provide paste at the positions which need welding, rather than fill the whole cell substrate 311 with the past, which reduces the amount of raw materials considerably to lower the cost.
In some specific embodiments of the present application, the back welding portions 314 have a width in a direction parallel to the back conductive wires 32B than the front conductive wires 312A. Preferably, a distance between adjacent rows of the back welding portions 314 is greater than that between adjacent front secondary grid lines 312A.
Specifically, the back welding portions 314 do not need to consider the shading problem, so they can be arranged into a broader structure with respect to the front secondary grid lines 312A, thereby occupying a larger area. Since the back electric fields 313 have a much better conductive performance, the distance between the back welding portions 314 can be much greater than that of the front secondary grid lines 312A.
Preferably, there are 5 to 30 rows of back welding portions 314. Further, the back welding portions 314 have a width of 0.05 to 3 mm in the direction parallel to the back conductive wires 32B. More preferably, the width of the back welding portions 314 is 0.2 to 1.5 mm.
That's to say, the back welding portions 314 are arranged into 5 to 30 rows in the direction of left to right, and each back welding portion 314 has a preferable width of 0.2 to 1.5 mm in the direction of left to right. Thus, on the basis of cost control, the welding performance of the back welding portions 314 and the back conductive wires 32B can be guaranteed effectively.
According to an embodiment of the present application, part of the back welding portions 314 is inserted into the back electric field 313. Preferably, the back welding portions 314 are higher than the back electric fields 313 by 0.003-0.03 mm. Further, the back welding portions 314 are higher than the back electric fields 313 by 0.005-0.01 mm.
In other words, the back electric field 313 are disposed on the back surface of the cells substrate 311, and at least one part of the upper portion of the back welding portions 314 is inserted into the back electric field 313, and the back welding portions 314 are higher than the back electric fields 313 by 0.005-0.01 mm in the direction from up to down. Therefore, the welding performance of the back welding portions 314 and the back conductive wires 32B can be further guaranteed effectively.
In the following, the solar cell array 30 will be described according to the embodiments of the present application.
According to the embodiments of the present application, the solar cell array 30 includes a plurality of solar cells which are the solar cells according to the above embodiment, cells 31 of adjacent cells being connected by the metal wire S. The metal wire S 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 front conductive wires 32A and/or back conductive wires 32B.
That's to say, two adjacent cells 31 are connected by the conductive wires 32. The conductive wires 32 include the front conductive wires 32A located on the upper surface of the cell 31 and the back conductive wires 32B located on the lower surface of the cell 31. The conductive wires 32A and the back conductive wires 32B are both constituted by metal wires S.
In another embodiment, as shown in FIG. 2B and FIG. 4B, the conductive wires 32 of the solar cell unit are constituted by a metal wire whose cross section has a width gradually decreasing in a direction away from the cell 31.
In other words, take the conductive wires 32 disposed above the cell 31 for example. The shape of the cross section of the conductive wires 32 gradually increase from up to down. The upper surface of the conductive wires 32 is a front surface, and the lower surface thereof is a contact surface with the cell 31. The conductive wires 32 of this structure have an upper surface area smaller than a lower surface area. The conductive cross section of the conductive wires 32 with the cell 31 is improved at the same time of reducing the shaded area. The contact area of the conductive wires 32 with the cell 31 is relatively large, which can improve conductivity. Meanwhile, since the conductive wires have an inclining side surface, the sunlight irradiating onto the tilting surface will be reflected to the front surface partially to raise light intensity and correspondingly reduce the shaded surface, so as to improve the photoelectric conversion efficiency.
Thus, the conductive wires 32 of the solar cell unit according to the embodiments of the present disclosure are constituted by the metal wire whose cross section has a width gradually decreasing in a direction away from the cell 31. That's to say, the area of the contact surface of the metal wire with the cell 31 is larger than that of the surface of the metal wire opposite the contact surface. The conductive cross section of the metal wire with the cell 31 is improved at the same time of reducing the shaded area, so as to improve the photoelectric conversion efficiency.
Alternatively, in some specific embodiments of the present disclosure, the cross section of the metal wire is a triangle. In some other embodiments, the cross section of the metal wire is a trapezoid. Alternatively, the metal has a height of 0.2 to 0.5 mm.
That's to say, the metal has a thickness of 0.2 to 0.5 mm with respect to the cell 31. Thus, the conductive wires 32 constituted by the metal wire of this structure are connected with the cell 31 more stably, which not only can guarantee the conductive cross section of the metal wire with the cell 31, but also can reduce the shaded area.
As shown in FIG. 4B, according to one embodiment of the present disclosure, the conductive wires 32 are a copper wire coated with a connection material 322, i.e. the conductive wires 32 are constituted by the metal wire body 321 and the connection material 322 coating the metal wire body 321.
Alternatively, the connection material 322 is a welding layer. Further, the welding layer is an alloy layer. In some other specific embodiments of the present disclosure, the connection material 322 is a conductive adhesive.
That's to say, the metal wire body 321 is coated with the connection material 322, such as a conductive adhesive or a welding layer, so as to facilitate electric connection of the metal wire body 321 and the cell 31, and avoid affecting the photoelectric conversion efficiency due to the drifting of the metal wire during the connection process. Of course, the electric connection of the metal wire body 321 and the cell 31 can be conducted when or before the solar cell module is laminated. Preferably, they are connected before laminating.
As shown in FIG. 1 to FIG. 11, the solar cell unit according to the embodiments of the present application includes a cell 31 and conductive wires 32. The cell 31 consists of a cell substrate 311 and secondary grid lines 312 disposed on a front surface of the cell substrate 311; the conductive wires 32 are disposed on the front surface of the cell substrate 311, intersected and connected with the secondary grid lines 312, and the conductive wires 32 are the conductive wires 32 of the solar cell unit according to the above embodiments.
In other words, the solar cell according to the present application is mainly formed with the cell 31 and conductive wires 32; the cell 31 is mainly constituted by the cell substrate 311 and secondary grid lines 312. In the present application, the conductive cross section area of the conductive wires 32 and the cell 31 is relatively large, so as to improve the performance of the cell.
According to yet another embodiment, the conductive wires 32 of the solar cell unit will be described.
As shown in FIG. 2C to FIG. 4C, the conductive wires 32 of the solar cell unit according to the embodiments of the present disclosure are constituted by a metal wire whose height is H, and whose width is W, a ratio of the height H and the width W being greater than 1:1.
Specifically, take the conductive wires 32 disposed on the cell 31 for example. As for the conductive wires 32 according to the embodiments of the present disclosure, the ratio between the height H in the direction from up to down and the width W in the direction from left to right is greater than 1:1.
It shall be noted that if the melting connection is employed, for example, welding connection, after the conductive wires are connected with the secondary grid lines of the cell unit, part of the conductive wires may melt to be electrically connected with the secondary grid lines, such that the ratio of the height H and the width W of the conductive wires welded may be smaller than 1:1. Thus, the present disclosure refers to the ratio of the height and the width of the metal wire before welding, rather than the ratio of the height and the width of the conductive wires welded.
In other words, the conductive wires 32 according to embodiments of the present disclosure have a height-width ratio of greater than 1, such that the conductive wires 32 can make full use of the space in the direction of the height thereof, so as to increase the cross section of the conductive wires. In other words, the conductive cross section can be enlarged with the same shaded area of a single conductive wire. When the shaded area (i.e. the cross section) of the single conductive wire is identical, the shaded area of the conductive wires in the present disclosure is smaller, so more conductive wires can be adopted, to increase the conductive cross section of the conductive wire overall, so as to improve the performance of the cell.
Preferably, according to an embodiment of the present disclosure, the ratio of the height H and the width W is smaller than 6:1. More preferably, the ratio of the height H and the width W ranges from 1.5:1 to 3:1. In some specific embodiments of the present disclosure, the width W ranges from 0.04 mm to 0.2 mm. Preferably, the width W ranges from 0.08 mm to 0.2 mm.
Alternatively, the height H ranges from 0.15 mm to 0.8 mm. Further, the height H ranges from 0.2 mm to 0.5 mm.
Thus, the conductive cross section of the conductive wires 32 with the cell 31 can be configured to be larger, so as to further improve the performance of the cell.
As shown in FIG. 4C, in the present disclosure, the conductive wires 32 are a copper wire coated with a connection material 322, i.e. the conductive wires 32 are constituted by the metal wire 321 and the connection material 322 coating the metal wire 321.
Alternatively, the connection material 322 is a welding layer. Further, the welding layer is an alloy layer. In some other specific embodiments of the present disclosure, the connection material 322 is a conductive adhesive.
That's to say, the metal wire 321 is coated with the connection material 322, such as a conductive adhesive or a welding layer, so as to facilitate electric connection of the metal wire 321 and the cell 31, and avoid affecting the photoelectric conversion efficiency due to the drifting of the metal wire during the connection process. Of course, the electric connection of the metal wire 321 and the cell 31 can be conducted when or before the solar cell module is laminated. Preferably, they are connected before laminating.
In some specific embodiments of the present disclosure, the metal wire has a rectangular cross section. Further, a lead angle is disposed on two upper angles of the rectangle. Thus, the metal wire of this structure can reflect the light to the cell, which further improves light intensity on the cell, so as to improve photoelectric conversion efficiency.
In the following, the solar cell array 30 will be described according to the embodiments of the present disclosure.
According to the embodiments of the present disclosure, the solar cell array 30 includes a plurality of solar cell units which are the solar cell units according to the above embodiment, cells 31 of adjacent cell units being connected by the conductive wires 32.
Since the solar cell unit according to the above embodiment of the present disclosure has the above technical effect, the solar cell array 30 according to the embodiment of the present disclosure has the corresponding technical effect, i.e. saving the materials for manufacturing the secondary grid lines 312 and lowering the cost.
Specifically, in some embodiments of the present disclosure, the conductive wires are constituted by the metal wire S which extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31.
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 is formed with a plurality of cell units; the conductive wires 32 of the plurality of cells are formed by the metal wire body 321 which extends reciprocally between the surfaces of the cells 31.
It shall be understood that the term “extending reciprocally” in this disclosure can be called “winding” which means that the metal wire S extends between the surfaces of the cells 31. For example, referring to FIG. 1, in some circumstances, the metal wire extends between the surfaces of the cells 31 in the same plane, such as either between the front surfaces or between the bottom surfaces of the cells, to form a serpentine pattern. In some other circumstances, the metal wire S extends between the surfaces of the cells 31 in multiple planes, such as between both the front surface of a cell and the bottom surface of an adjacent cell, to form a serpentine pattern. In yet other circumstances, the metal wire S extends between the surfaces of the cells 31 both in the same plane and in multiple planes, such as sometimes between either the front surfaces or the bottom surfaces of some adjacent cells, and at other times between both the front surface of a certain cell and the bottom surface of an adjacent cell, to form a serpentine pattern. The plurality of conductive wires equals two or more passes of the serpentine shaped pattern. Preferably, two or more passes of the serpentine shaped pattern on the same plane are substantially parallel to each other. More preferably, all the passes of the serpentine shaped pattern on the same plane are substantially parallel to each other.
In the present disclosure, it shall be understood in a broad sense that “the metal wire S extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31. For example, the metal wire S may extend reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31; the metal wire S may extend from a surface of the first cell 31 through surfaces of a predetermined number of middle cells 31 to a surface of the last cell 31, and then extends back from the surface of the last cell 31 through the surfaces of a predetermined number of middle cells 31 to the surface of the first cell 31, extending reciprocally like this.
In addition, when the cells 31 are connected in parallel by the metal wire S, the metal wire S can extend on front surfaces of two cells, such that the metal wire S constitutes a front conductive wire 32A of two cells connected in series. Alternatively, a first metal wire S extends reciprocally on a front surface of a cell 31, and a second metal wire S extends reciprocally on a back surface of the cell 31, 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 body 321 extends reciprocally once to form two conductive wires 32 which form a U-shape or V-shape structure by the metal wire body 321 extending reciprocally, 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 cell units are constituted by the metal wire body 321 which extends reciprocally; and the adjacent cells 31 are connected by the conductive wires 32. Hence, the conductive wires 32 of the cell units in the present disclosure are used to output the current, and are not necessarily printed by 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 body 321 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 body 321 which extends reciprocally, the width of the conductive wires 32 (i.e. the width of projection of the metal wire on the cell) is much smaller than that of the current primary grid lines printed by silver paste, thereby decreasing the shaded area. 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 body 321 extends reciprocally to form the conductive wires, when the cell array 30 is used to manufacture the solar cell module 100, the metal wire body 321 is easier to control accurately and 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.
Therefore, the solar cell array 30 according to the embodiments of the present disclosure has low cost and high photoelectric conversion efficiency.
In the following, the solar cell array 30 according to specific embodiments of the present disclosure will be described with reference to the drawings.
The solar cell array 30 according to a specific embodiment of the present disclosure is illustrated with reference to FIG. 1 to FIG. 3.
In the embodiment shown in FIG. 1 to FIG. 3, two cell units in the solar cell array 30 are shown. In other words, it shows two cells bodies 31 connected with each other via the conductive wire 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.
Specifically, in an embodiment of the present disclosure, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31.
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 front 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 an embodiment of the present disclosure, back electrodes 314 are disposed on the back surface of the cell substrate 311, and the metal wire is welded with the back electrodes 314.
That's to say, in the embodiment, front secondary grid lines 312A are disposed on the front surface of the cell substrate 311, and back electrodes 314 are disposed on the back surface thereof. When the conductive wires 32 are located on the front surface of the cell substrate 311, the conductive wires 32 are welded with the front secondary grid lines 312A; when the conductive wires 32 are located on the back surface of the cell substrate 311, the conductive wires 32 are welded with the back electrodes 314 on the back surface of the cell substrate 311.
In some embodiments, there is a metal wire S. The metal wire S 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 2.5 mm to 15 mm. 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 forms 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 forms a V-shape structure.
In some embodiments, preferably, the metal wire is a copper wire, yet the present disclosure is not limited thereto. For example, the metal wire body 321 may be an aluminum wire. Preferably, the metal wire body 321 has a circular cross section, such that more sunlight can reach the cell substrate to further improve the photoelectric conversion efficiency.
More preferably, as shown in FIG. 4, the metal wire body 321 is coated with a connection material layer 322, such as a conductive adhesive layer or a welding layer. The metal wire is welded with the secondary grid line and/or the back electrode by the welding layer, such that it is convenient to electrically connect the metal wire with the secondary grid line and/or the back electrode, 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 wire with the cell can be conducted when or before the solar cell module is laminated, and preference is given to the latter.
In some embodiments, preferably, before the metal wire contact the cell, the metal wire extends under a strain, i.e. straightening the metal wire. After the metal wire is connected with the secondary grid line and the back electrode of the cell, the strain of the metal wire can be released, so as to further avoid the drifting of the conductive wire when the solar cell module is manufacture, and to guarantee the photoelectric conversion efficiency.
FIG. 5 is a schematic diagram of a solar cell array according to another embodiment of the present disclosure. As shown in FIG. 5, the metal wire extends reciprocally between the front surface of the first cell 31A and the front surface of the second cell 31B, such that the metal wire constitutes front conductive wires of the first cell 31A and 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.
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^throw and a surface of a cell in a (a+1)^throw, 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^throw and a back surface of a cell 31 at an end of the (a+1)^throw, 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^throw and the surface of the cell 31 at an end of the (a+1)^throw, the end of the a^throw and the end of the (a+1)^throw 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 Figs. 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 0.1 N to 0.8 N. That's to say, the binding force between the conductive wires 32 and the cells 31 ranges from 0.1 N to 0.8 N. Preferably, the binding force between the metal wire and the cells ranges from 0.2 N to 0.6 N, 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.
Preferably, there is a metal wire extending reciprocally between adjacent cells 31 in a row; and there is a metal wire extending reciprocally between cells 31 in adjacent rows. Thus, adjacent cells 31 can be connected by a single metal wire that extends reciprocally for several times, which is easier to manufacture in lower cost.
In an embodiment of the present disclosure, the metal wire is coated with a welding layer. The ratio of the thickness of the welding layer and the diameter of the metal wire is (0.02-0.5):1.
That's to say, in the cell array 30, the ratio of the thickness of the welding layer and the diameter of the conductive wire 32 (including the front conductive wire 32A and back conductive wire 32B) is (0.02-0.5):1.
In the present disclosure, the conductive wires 32 (including the front conductive wires 32A and back conductive wires 32B) consist of a metal wire and a welding layer coating the metal wire. The welding layer may coat the metal wire completely or partially. When the welding layer coats the metal wire partially, the alloy layer is, preferably, formed at a position where the welding layer is welded with the secondary grid lines 312 of the cell 31. When the welding layer coats the metal wire completely, the welding layer can coat the periphery of the metal wire in a circular manner. The thickness of the welding layer can fall into a relatively wide range. Preferably, the welding layer has a thickness of 1 to 100 μm, more preferably, 1 to 30 μm).
The alloy with a low melting point for forming the welding layer may be a conventional alloy with a low melting point which can be 100 to 220° C. 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 welding layer can be 0.001 to 0.06 mm. The conductive wire 32 may have a cross section of 0.01 to 0.5 mm². The metal wire can be conventional in the art, for example, a copper wire.
Moreover, in the present application, the secondary grid line 312 has a width of 40 to 80 μm and a thickness of 5 to 20 μm; there are 50 to 120 secondary grid lines 312, and the distance between adjacent secondary grid lines 312 ranges from 0.5 to 3 mm.
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 are 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. The 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 156 mm×156 mm, the solar cell module has a series resistance of 380 to 440 mΩ 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 528 mΩ, 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 156 mm×156 mm, the solar cell module has an open-circuit voltage of 37.5-38.5 V 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 9.4 A, and is not related to 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 156 mm×156 mm, the solar cell module has a working voltage of 31.5-32 V 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 8.6 A, and is not related to the number of the cells.
In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156 mm×156 mm, the solar cell module has a conversion efficiency of 16.5-17.4%, and a power of 265-280 W 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. 1 to FIG. 3 and FIG. 7 to FIG. 9.
Specifically, the method according to the embodiments of the present disclosure includes the following steps:
providing a cell 31 which includes a cell substrate 311 and a secondary grid line 312 disposed on a front surface of the cell substrate 311;
welding a conductive wire 32 constituted by a metal wire with the secondary grid line 312 to obtain a solar cell unit, in which the secondary grid line 312 has a width in a welding position with the conductive wire 32 greater than a width thereof in a non-welding position;
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.
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 on 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 a strain. As shown in FIG. 8, a first cell 31A and a second cell 31B are prepared. As shown in FIG. 9, a front surface of the first cell 31A is connected with a metal wire, and a back surface of the second cell 31B is connected with the metal wire, such that the cell array 30 is formed. FIG. 9 shows two cells 31. 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.
According to another embodiment of the present disclosure, the method includes the following steps:
providing a cell 31 which includes a cell substrate 311, secondary grid lines 312 spaced apart from each other in a front surface of the cell substrate 311, a back electric field 313 disposed in a back surface of the cell substrate 311, and back welding portions 314 spaced apart from each other in the back electric field 313, the back welding portions 314 formed by applying silver paste or a tin alloy to the back field 313; connecting front conductive wires 32A constituted by a metal wire with the front secondary grid lines 312A, and connecting back conductive wires 32B constituted by a metal wire with the back field 313 via the back welding portions 314, to obtain a solar cell unit; 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.
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 on 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.
The back electric filed 313 is disposed on the back surface of the cell substrate 311, and back welding portions 314 are formed on the back electric field 313 by applying the silver paste or the tin alloy (for example applying the silver paste or the tin alloy by screen printing). The back conductive wires 32B are disposed on the back surface of the cell substrate 311 and are located on the back welding portions 314. The back conductive wires 32B are constituted by the metal wire S and are electrically connected with the back welding portions 314.
Specifically, as shown in FIG. 7, the metal wire extends reciprocally for 12 times under a 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 welding portion 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° C.) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.04 mm², and the alloy layer has a thickness of 16 μm. Hence, the metal wire S is obtained.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm are provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. Each secondary grid line is provided with 14 gaps. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm 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 31 mm.
60 cells 31 are arranged in a matrix form. 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 a strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The secondary grid line of the first cell 31 is welded with the conductive wire, the secondary grid lines between two adjacent conductive wires being evenly distributed with one gap, and the back electrode of the second cell 31 is welded with the conductive wire at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 9.9 mm.
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 front 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 back 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 each secondary grid line 312 is a metal wire disposed continuously, so as to obtain a solar cell module D1.

Example 2

The difference of Example 2 and Example 1 lies in that the gap has a length of 3 mm in the length direction of the secondary grid line, so as to obtain a solar cell module A2.

Example 3

The difference of Example 3 and Example 1 lies in that the gap has a length of 5 mm in the length direction of the secondary grid line, so as to obtain a solar cell module A3.

Example 4

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° C.) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.03 mm², and the alloy layer has a thickness of 10 μm. Hence, the metal wire S is obtained.
(2) Manufacturing a Solar Cell Module 100
A EVA adhesive layer in 1630×980×0.5 mm are provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm) in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. Each secondary grid line is provided with 19 gaps. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm 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 31 mm.
60 cells 31 are arranged in a matrix form. 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 a strain from two clips at two ends thereof, so as to form 20 parallel conductive wires. The secondary grid line of the first cell 31 is welded with the conductive wire, the secondary grid lines between two adjacent conductive wires being evenly distributed with one gap, and the back electrode of the second cell 31 is welded with the conductive wire at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 7 mm.
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 front 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 back 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 A4 is obtained.

Example 5

The solar cell module is manufactured according to the method in Example 4, but the difference compared with Example 4 lies in that each secondary grid line is provided with 14 gaps. The secondary grid lines between part of adjacent conductive wires are evenly distributed with the gaps, while the secondary grid lines between other part of adjacent conductive wires are continuously arranged, so as to obtain a solar cell module A5.

Testing Example 1

(1) 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: 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 1.

TABLE 1

Solar cell module	A1	D1	A2	A3	A4	A5

Photoelectric conversion	17.1	16.8	16.9	16.7	17.2	17.1
efficiency (%)

As for the solar cell module according to the embodiments of the present disclosure, the gaps are disposed on the secondary grid lines, i.e. the silver paste is not printed at the gaps, which can reduce the amount of the silver paste and reduce the cost. It can be indicated from Table 1 that the gaps disposed on the secondary grid lines will not affect the photoelectric conversion efficiency of the solar cell, and the solar cell module according to the embodiments of the present disclosure can obtain relatively high photoelectric conversion efficiency can be obtained.

Example 11

Example 11 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
A copper wire is attached to an alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.), in which the copper wire has a cross section of 0.04 mm², and the alloy layer has a thickness of 16 μm, so as to obtain the metal wire S.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm are provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back welding portions on its back surface, and the back welding portions are formed by applying the silver paste to the back electric field. Each back welding portion substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back welding portions is 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell under a strain. The metal wire extends reciprocally under strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The metal wire extends reciprocally under strain from two clips at two ends thereof, 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 at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 9.9 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar.
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 front 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 back 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 A11 is obtained.

Comparison Example 11

The difference of Comparison example 11 and Example 11 lies in that no welding portion is disposed on the back surface of the cell, i.e. the back conductive wires being welded with the back electric filed directly. Thus, a solar cell module D11 is obtained.

Example 12

Example 12 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
A copper wire is attached to an alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.), in which the copper wire has a cross section of 0.03 mm², and the alloy layer has a thickness of 10 μm, so as to obtain the metal wire S.
(2) Manufacturing a Solar Cell Module
A EVA adhesive layer in 1630×980×0.5 mm are provided (melting point: 60° C.), and a glass plate in 1650×1000×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five non-continuous back welding portions on its back surface, and the back welding portions are formed by applying the silver paste to the back electric field. Each back welding portion substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back welding portions is 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell under strain, so as to form 20 parallel conductive wires. The secondary grid line of the first cell 31 is welded with the primary grid, and the back welding portion of the second cell 31 is welded with the primary grid, and the distance between parallel conductive wires is 7 mm. 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, the shady surface thereof facing the back adhesive layer 40, and they are laminated in a laminator so as to obtain a solar cell module A12.

Example 13

The solar cell module is manufactured according to the method in Example 11, but the difference compared with Example 11 lies in that the back surface of the cell is provided with 20 welding portions, so as to obtain a solar cell module A13.
Performance Test
(1) Welding-Binding Force Test Between the Edge Secondary Grid Lines and the Metal Wire
The welding-binding force in the solar cell modules A11-A15 and D11 will be tested in the following method respectively:
1. 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;
2. Clamping the metal wire at a pull ring of a tension meter that forms an angle of 45° with the cell;
3. 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.
(2) Photoelectric Conversion Efficiency Test
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): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 2.

Welding-binding force (N)	0.4	0.1	0.36	0.49	0.4	0.1
Photoelectric conversion	16.8	15.3	16.9	17.2	16.8	15.3
efficiency (%)

It can be indicated from Table 2 that the solar cell module according to the embodiments of the present disclosure has greater welding-binding force between the metal wire and the back welding portions, i.e. higher welding strength between the metal wire and the back surface of the cell, and obtains relatively high photoelectric conversion efficiency.

Example 31

Example 31 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
A copper wire is attached to an alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.), in which the copper wire has a trapezoid cross section of 0.04 mm², a height of 0.2 mm, a upper bottom with of 0.1 mm and a lower bottom width of 0.3 mm, and the alloy layer has a thickness of 16 μm, so as to obtain the metal wire S.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm are provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm 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 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell under strain. The metal wire extends reciprocally under strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The metal wire extends reciprocally under a strain from two clips at two ends thereof, 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 at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 9.9 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar.
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 front 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 back 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 A31 is obtained.

Comparison Example 31

The difference of Comparison example 1 and Example 1 lies in that the cross section of the wire copper is a trapezoid, and has an area of 0.2 mm×0.2 mm. Thus, a solar cell module D31 is obtained.

Example 2

The solar cell module is manufactured according to the method in Example 31, but the difference compared with Example 1 lies in that the cross section of the wire copper for forming the conductive wires is triangular, and has a height of 0.3 mm, a bottom with of 0.3 mm, so as to obtain a solar cell module A32.

Testing Example 31

(1) 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: 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 3.

	TABLE 3

	Solar cell module

	A31	A32	D31

Photoelectric conversion efficiency	16.9	17.1	16.7
(%)

It can be indicated from Table 3 that the solar cell module according to the embodiments of the present disclosure can obtain relatively high photoelectric conversion efficiency.

Example 41

Example 41 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof
(1) Manufacturing a Conductive Wire
A copper wire is attached to an alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.), in which the copper wire has a rectangular cross section; the ratio of the width and the height of the copper wire is 1:2; and the area of the cross section is 0.04 mm²; and the alloy layer has a thickness of 16 μm. Thus, the conductive wires are obtained.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm are provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm 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 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell under strain. The metal wire extends reciprocally under strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The metal wire extends reciprocally under a strain from two clips at two ends thereof, 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 at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 9.9 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar.
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 front 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 back 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 A41 is obtained.

Comparison Example 41

The difference of Comparison example 41 and Example 41 lies in that the copper wire has a height of 0.1 mm and a width of 0.2 mm. In such a way, a solar cell module D41 is obtained.

Example 42

The difference of Example 42 and Example 41 lies in that the ratio of the height and the width of the copper wire is 4:1, the height being 0.6 mm and the width being 0.15 mm. In such a way, a solar cell module A42 is obtained.

Example 43

The difference of Example 43 and Example 41 lies in that the ratio of the height and the width of the copper wire is 6:1, the height being 0.9 mm and the width being 0.15 mm. In such a way, a solar cell module A43 is obtained.

Testing Example 41

(1) 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: 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 4.

	TABLE 4

	Solar cell module

	A41	D41	A42	A43

Photoelectric conversion efficiency	16.7	15.8	16.8	16.9
(%)

It can be indicated from Table 4 that the solar cell module according to the embodiments of the present disclosure can obtain relatively high photoelectric conversion efficiency.
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.

Solar cell module

1. A solar cell unit, comprising:

a cell including a cell substrate and a plurality of secondary grid lines disposed on a front surface of the cell substrate; and

a plurality of conductive wires spaced apart from each other, the plurality of conductive wires intersecting and connected with the secondary grid lines, in which at least one secondary grid line has at least one gap located between adjacent conductive wires.

2. The solar cell unit according to claim 1, wherein there are n conductive wires; and there is/are n−1 gap(s) in a single secondary grid line.

3. The solar cell unit according to claim 2, wherein there is a gap between adjacent conductive wires.

4-5. (canceled)

6. The solar cell unit according to claim 1, wherein the gap is located in a middle position of the adjacent conductive wires.

7. (canceled)

8. The solar cell unit according to claim 1, wherein the conductive wires comprise a metal wire.

9. (canceled)

10. The solar cell unit according to claim 8, wherein the metal wire is coated with a welding layer by which the conductive wires are welded with the secondary grid lines.

11. The solar cell unit according to claim 10, wherein the secondary grid line has a width in a welding position with the conductive wire greater than in a non-welding position.

12. (canceled)

13. The solar cell unit according to claim 1, further comprising a short grid line disposed on the front surface of the cell substrate; the secondary grid lines including a middle secondary grid line intersected with the conductive wires and an edge secondary grid line non-intersected with the conductive wires; the short grid line connected with the edge secondary grid line, and with the conductive wires or at least one middle secondary grid line.

14. The solar cell unit according to claim 13, wherein the short grid lines are connected with the middle secondary grid lines closest to the edge secondary grid lines.

15. A solar cell array, comprising a plurality of solar cell units according to claim 1, cells of adjacent cell units being connected by the conductive wires.

16. The solar cell array according to claim 15, wherein the conductive wire comprises a metal wire; and the metal wire extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell.

17. The solar cell array according to claim 16, wherein the metal wire extends reciprocally between a front surface of the first cell and a back surface of the second cell.

18. The solar cell array according to claim 17, wherein a back electrode is disposed on the back surface of the cell substrate, and the metal wire is welded with the back electrode of the second cell.

19-21. (canceled)

22. The solar cell array according to claim 16, wherein the cells are arranged in an n×m matrix form, n representing a column, and m representing a row;

in a row of cells, the metal wire extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell; in two adjacent rows of cells, the metal wire extends reciprocally between a surface of a cell in a a^throw and a surface of a cell in a (a+1)^throw; and m−1≧a≧1.

23. The solar cell array according to claim 22, wherein in two adjacent rows of cells, the metal wire extends reciprocally between a surface of a cell at an end of the a^throw and a surface of a cell at an end of the (a+1)^throw, the end of the a^throw and the end of the (a+1)^throw located at the same side of the matrix form.

24. The solar cell array according to claim 23, 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 the cell at the end of the a^throw and a back surface of the cell at the end of the (a+1)^throw, to connect the two adjacent rows of cells in series.

25. The solar cell array according to claim 22, wherein one metal wire extends reciprocally between adjacent cells in a row; and another metal wire extends reciprocally between cells in adjacent rows.

26-31. (canceled)

32. A solar cell module, comprising an upper cover plate, a front adhesive layer, a solar cell array of claim 15, a back adhesive layer and a back plate superposed in sequence.

33. A method for manufacturing a solar cell module, comprising:

providing a cell which includes a cell substrate and a plurality of secondary grid lines disposed on a front surface of the cell substrate;

intersecting and connecting conductive wires comprising a metal wire with the secondary grid lines to obtain a solar cell unit, in which at least one secondary grid line has at least one gap located between adjacent conductive wires;

superposing an upper cover plate, a front adhesive layer, the solar cell unit, 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 the superposed layers to obtain the solar cell module.

34. (canceled)

35. The method according to claim 33, wherein the metal wire extends reciprocally on a surface of the cell.

36-111. (canceled)