WO2021036801A1

WO2021036801A1 - New metal-semiconductor-contact-type multi-busbar single crystalline efficient cell

Info

Publication number: WO2021036801A1
Application number: PCT/CN2020/108876
Authority: WO
Inventors: 王岚; 李忠涌; 张忠文; 谢毅
Original assignee: 通威太阳能（成都）有限公司; 通威太阳能(眉山)有限公司
Priority date: 2019-08-29
Filing date: 2020-08-13
Publication date: 2021-03-04
Also published as: CN210403748U

Abstract

Disclosed is a new metal-semiconductor-contact-type multi-busbar single crystalline efficient cell, belonging to the technical field of solar cells, and aiming to overcome the disadvantages of the prior art, to solve the problem of a hidden crack easily occurring at a connection position between a traditional busbar and a frame, and to solve the problem of an intersection and connection position between a finger and a welding spot or a busbar easily cracking after being subjected to a thermal cycling test. Connecting forks are provided at two end portions of a busbar in a cell. Each connecting fork comprises an end head and two end portion branches. One end of each of the two end portion branches is connected to the end head, and the other end of each of the two end portion branches extends to a frame line and comes into contact with the frame line. The end head and the two end portion branches form a U-shaped structure. Transition sections are respectively arranged at an intersection position between a finger and the busbar and at an intersection position between the finger and a welding spot. The present utility model is applicable to a solar cell.

Description

A new type of gold half-contact multi-bus grid single crystal high-efficiency battery

Technical field

The utility model belongs to the technical field of solar cells, and specifically relates to a new type of gold semi-contact type multi-main grid single crystal high-efficiency battery.

Background technique

Part of the sunlight irradiated on the solar cell enters the cell, and the other part is reflected by the surface of the cell. Only when it is successfully injected into the solar cell, excites the electron-hole pairs, and is successfully separated by the PN junction, can it be converted into effective electrical energy. When the charge leaves the PN junction and converges to the electrode, it will suffer from various resistance losses such as the resistance of the diffusion layer on the top of the battery, the contact resistance between the sub-gate and silicon material, the sub-gate resistance, and the main-gate resistance. When the number of main grids increases, the current transmission distance of the secondary grids decreases, and the corresponding power loss is inversely proportional to the square of the transmission distance. It is based on this principle that the power loss of the module gradually decreases with the increase of the number of main grids.

Existing solar cells generally adopt a new type of gold semi-contact multi-lead electrode design combined with high-resistance dense grid technology to further improve cell conversion efficiency. With the increase in the number of main grids, the width of the main grid needs to be further reduced. By reducing the width of the main grid, the surface shading and silver paste consumption can be reduced while maintaining or reducing the conduction resistance, which will reduce the overall photovoltaic solar cell manufacturing process. This efficiency improvement is of great significance.

In the current multi-bus grid solar cell, the end of the main grid is generally in direct contact with the frame line. Because the bus grid and the frame line have a certain height, when the film is pressed down, it may appear due to the height difference and instantaneous high temperature and high pressure. Hidden cracks affect the yield of solar panels.

At present, domestic solar panel manufacturers have improved the end of the main grid into a V-shaped connection fork during production, such as the multi-bus grid solar panel structure disclosed by patent application number: 2018213611045 and patent application number: 2018216043091. Including the V-shaped connection fork, this V-shaped connection fork is less likely to crack when exposed to instantaneous high temperature and high pressure than the structure where the main grid is directly in contact with the frame line, but there is still a risk of cracking.

Utility model content

The purpose of the utility model is to overcome the shortcomings of the prior art, provide a new type of gold semi-contact type multi-bus grid single crystal high-efficiency battery, solve the problem that the traditional main grid and the frame connection position are prone to cracks, and solve the problem of sub-grid lines The solder joints or busbar line transfer positions are easy to break after being subjected to the thermal cycle test.

The technical scheme adopted by the utility model is as follows:

A new type of gold semi-contact multi-bus grid single crystal high-efficiency battery includes a substrate, a positive electrode arranged on the front surface of the substrate, and a back electrode arranged on the back electric field of the substrate. The positive electrode includes a frame line and is arranged in the frame line A plurality of main grid lines arranged in parallel and a plurality of auxiliary grid lines arranged in parallel, a plurality of the main grid lines intersect with a plurality of the auxiliary grid lines perpendicularly, and a plurality of solder joints are arranged on the main grid lines at intervals , The two ends of the main grid line are provided with connecting forks, the connecting forks include an end and two end parts, one end of the two end parts is connected to the end, and the other end of the two end parts extends to the frame line And contact, the end and the two end parts branch to form a U-shaped structure;

The intersection position of the secondary grid line and the main grid line and the intersection position of the secondary grid line and the solder joint are respectively provided with a gradation section, one end of the gradation section is connected to the main grid line or the solder joint, and the other end of the gradation section is connected to the secondary grid line; The width of the gradation section gradually narrows from the end close to the main grid line to the end far away from the main grid line, or the width of the gradation section gradually narrows from the end close to the solder joint to the end far away from the solder joint.

Further, the intersection position of the secondary grid line and the end and the intersection position of the secondary grid line and the two end portions are respectively provided with gradual changes.

Further, the end head and the two end parts branch to form a 凵-shaped structure.

Further, the end and the two end parts are branched to form a trapezoidal structure, the distance between the two end parts near the end is small, and the distance between the two end parts far away from the end is large.

Further, a plurality of break openings are arranged at intervals on the border line.

Further, the solder joint has a rectangular structure with rounded corners, the narrow side length of the solder joint is 0.6 mm ± 0.2 mm, and the wide side length of the solder joint is 1 mm ± 0.2 mm.

Further, the length of the gradual change section is 0.6mm±0.2mm.

Further, the widest value of the gradual change section is 0.1±0.01mm, and the narrowest value of the gradual change section is 0.05±0.03mm.

Further, the width of the space between the openings is 0.3±0.05 mm.

Further, the distance between two adjacent main grid lines is 12.4 ± 0.05 mm, and the distance between two adjacent secondary grid lines is 1.74 ± 0.05 mm.

In summary, due to the adoption of the above technical scheme, the beneficial effects of the present invention are:

1. In the present utility model, U-shaped connecting forks are used at both ends of the main grid line, and when the film is subjected to instantaneous high temperature and high pressure, there will be no hidden cracks, which increases the yield of large-scale production;

2. In the present utility model, the transfer position of the auxiliary grid line and the welding point and the main grid line adopts a gradual section structure, and there will be no breakage after the cold and hot cycle test;

3. In the present utility model, the width of the main grid line and the auxiliary grid line is reduced, and the amount of silver paste is reduced, which is beneficial to saving costs; at the same time, the reduction of the width of the main grid line and the auxiliary grid line can further increase the illumination The receiving area improves the light conversion efficiency.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the front surface of the battery slice of the utility model;

Figure 2 is an enlarged schematic diagram of the selection frame on the front surface A of the battery slice of the present invention;

Figure 3 is a schematic diagram of the structure of the gradual change section of the utility model;

Figure 4 is a schematic diagram of the structure of the U-shaped connecting fork of the utility model;

Figure 5 is a structural schematic diagram of the utility model 凵-shaped connecting fork;

Figure 6 is a schematic diagram of the structure of the trapezoidal connecting fork of the utility model;

Figure 7 is a schematic diagram of the structure of the double U-shaped connecting fork of the utility model;

Figure 8 is a schematic structural diagram of Embodiment 5 of the utility model;

Figure 9 is an enlarged schematic diagram of the selection frame of utility model B;

Marks in the picture: 10-connecting fork, 11-secondary grid line, 12-frame line, 13-main grid line, 14-soldering point, 15-end, 16-end partial branch, 17-gradient section.

detailed description

In order to make the purpose, technical solutions and advantages of the utility model clearer, the utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present utility model, and are not used to limit the present utility model.

Example 1

This embodiment provides a new type of gold half-contact multi-bus grid single crystal high-efficiency battery, including a substrate, a positive electrode provided on the front surface of the substrate, and a back electrode provided on the back electric field of the substrate. Please refer to Figure 1 and Appendix As shown in FIG. 2, the positive electrode includes a frame line 12 and a plurality of parallel main grid lines 13 arranged in the frame line 12 and a plurality of parallel auxiliary grid lines 11, a plurality of the main grid lines 13 and A plurality of the secondary grid lines 11 intersect vertically, and a plurality of solder joints 14 are arranged on the main grid line 13 at intervals;

Please refer to FIG. 4, the two ends of the main grid line 13 are provided with connecting forks 10, the connecting fork 10 includes an end 15 and two end parts 16, one end of the two end parts 16 and the end 15 Connected, the other ends of the two end partial branches 16 extend to and contact the frame line 12, and the end 15 and the two end partial branches 16 form a U-shaped structure;

Please refer to FIG. 3, the intersection position of the secondary grid line 11 and the main grid line 13 and the intersection position of the secondary grid line 11 and the solder joint 14 are respectively provided with a gradation section 17, one end of the gradation section 17 and the main grid line 13 or The solder joints 14 are connected, and the other end of the gradation section 17 is connected to the secondary grid line 11; the width of the gradation section 17 gradually narrows from the end close to the main grid line 13 to the end far away from the main grid line 13, or the gradation section The width of 17 gradually narrows from the end close to the solder joint 14 to the end far away from the solder joint 14.

The connecting fork 10 adopts a U-shaped structure, which has a higher yield rate than the traditional direct connection with the frame line 12, a V-shaped structure or a three-pronged line structure. The V-shaped structure is subjected to instantaneous high temperature and high pressure due to the force on the end point 15. It is also prone to breakage, and the three-pronged wire structure will not only increase the amount of silver paste, but the three-pronged wire also has end-point forces, and its effect is far less practical than the U-shaped structure.

The intersection position of the secondary grid line 11 and the main grid line 13 and the intersection position of the secondary grid line 11 and the solder joint 14 are respectively provided with a gradual change section 17. The intersection position of the gradual change section 17 and the main grid line 13 or the transition section 17 and the solder joint 14 In the cold and hot temperature test, if the width of the connection point is too small, it is easy to break, and the use of the gradual section 17 can not only solve this problem, but also reduce the secondary grid line 11 at the position that does not intersect with the main grid line 13. Width, saving the amount of silver paste.

Example 2

As shown in FIG. 5, the structure of the connecting fork 10 also includes a 凵-shaped structure. The two-end branches 16 of the connecting fork 10 are respectively connected to the terminal 15 and the two-end branches 16 and the terminal 15 form a 凵-shaped structure. The connecting fork 10 is similar to the U-shaped structure. When it is subjected to instantaneous high pressure, high temperature or cold and hot temperature tests, the end point of its cross line will not be too strong, and the risk of cracking will also be reduced.

Example 3

As shown in Figure 6, the structure of the connecting fork 10 also includes a trapezoidal structure. The end 15 and the two end portions 16 form a trapezoidal structure. The distance between the two end portions 16 near the end is small, and the two end portions 16 The distance away from the tip is large.

The two end branches of the connecting fork 10 are respectively connected with the end and the frame line 12 to form a trapezoid; the two ends of the connecting fork 10 have an inclined structure, because the connecting position of the two ends of the branch 16 and the end 15 does not converge into a point, so , When subjected to instantaneous high temperature and high pressure, the pressure on the terminal 15 will not be too large, and there will be no risk of cracking.

Example 4

As shown in FIG. 7, the structure of the connecting fork 10 also includes a double U-shaped structure, two U-shaped structures are superimposed on each other, and the end branches 16 of the two U-shaped structures are connected to the frame line 12 respectively. Although this structure increases the amount of silver paste, it ensures the conduction between the main grid line 13 and the frame line 12, and there will be no problem of fracture affecting the yield.

Example 5

As shown in Figures 8 and 9, the frame line 12 is provided with a plurality of breaks at intervals. This structure not only saves the slurry cost of the frame line 12, but at the same time, there are cracks in the secondary grid line 11, which is not like the frame line. The structure that 12 is completely disconnected from the secondary grid line 11 causes the circuit of the entire battery to be disconnected. This embodiment adopts a discontinuous frame line structure. When one of the secondary grid lines 11 is cracked, the other secondary grid lines can be used. 11 form a pathway.

Example 6

The shape of the gradual change section 17 also includes a spindle structure, a fusiform structure, an isosceles trapezoid structure or a triangular structure. The gradual change section 17 mainly effectively reduces the problems of grid broken and hidden cracks, and improves the stability of the solar cell operation.

Example 7

The length of the gradation section 17 in this embodiment is 0.6mm, the widest value of the gradation section 17 is 0.1mm, the narrowest value of the gradation section 17 is 0.05mm, and the width of the busbar line 13 is 0.1mm. Considering the busbar line 13 The width of the sub-gate line 11 and the influence of the light-shielding area reduces the width of the main gate line 13 and the sub-gate line 11, and can also reduce the amount of silver paste, thereby saving costs.

Example 8

The solder joint 14 of this embodiment has a rounded rectangular structure, the wide side length of the solder joint 14 is 1 mm, the narrow side length of the solder joint 14 is 0.6 mm, and the rounded rectangular solder joints 14 are evenly distributed on the main grid line 13. This makes the distribution of the force of the welding ribbon on the cell more even, disperses the packaging stress of the cell, and improves the reliability.

Example 9

This embodiment provides a solar cell, and the four corners of the solar cell sheet are chamfered.

The utility model adopts U-shaped connecting forks 10 at both ends of the main grid line 13, when the film is subjected to instantaneous high temperature and high pressure, there will be no hidden cracks, so that the yield rate of large-scale production is increased; the auxiliary grid line 11 and The transition position of the solder joint 14 and the main grid line 12 adopts the structure of the gradual section 17, which will not break after the cold and hot cycle test; the width of the main grid line 13 and the auxiliary grid line 11 is reduced, and the amount of silver paste is reduced , It is beneficial to save costs; at the same time, the width of the main grid line 13 and the auxiliary grid line 11 is reduced, which can further increase the light receiving area and improve the light conversion efficiency.

The above are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modification, equivalent replacement and improvement made within the spirit and principle of the utility model shall be included in this utility model. Within the scope of protection of utility models.

Claims

A new type of gold half-contact multi-bus grid single crystal high-efficiency battery, including a substrate, a positive electrode arranged on the front surface of the substrate, and a back electrode arranged on the back electric field of the substrate. The positive electrode includes a frame line (12) and A plurality of parallel main grid lines (13) and a plurality of parallel auxiliary grid lines (11) in the frame line (12), a plurality of the main grid lines (13) and a plurality of the auxiliary grids The lines (11) intersect vertically, and a plurality of solder joints (14) are arranged on the main grid line (13) at intervals, which is characterized in that:

The two ends of the main grid line (13) are provided with connecting forks (10). The connecting forks (10) include an end (15) and two end portions (16), one end of the two end portions (16) Connected to the end (15), the other ends of the two end partial branches (16) extend and contact the frame line (12), and the end (15) and the two end partial branches (16) form a U-shaped structure;

The intersection position of the secondary grid line (11) and the main grid line (13) and the intersection position of the secondary grid line (11) and the solder joint (14) are respectively provided with a gradation section (17), one end of the gradation section (17) and the main The grid line (13) or the solder joint (14) is connected, and the other end of the gradation section (17) is connected to the secondary grid line (11); the width of the gradation section (17) is from the end close to the main grid line (13) to The end away from the main grid line (13) gradually narrows, or the width of the gradual section (17) gradually narrows from the end close to the solder joint (14) to the end away from the solder joint (14).
A new type of gold half-contact multi-main grid single crystal high-efficiency battery according to claim 1, characterized in that the intersection position of the secondary grid line (11) and the end (15) and the secondary grid line (11) and two The intersecting positions of the end branches (16) are also respectively provided with gradual changes (17).
The new type gold half-contact multi-bus grid single crystal high-efficiency battery according to claim 1, characterized in that the end (15) and the two end partial branches (16) form a ridge-shaped structure.
A new type of gold half-contact multi-bus grid single crystal high-efficiency battery according to claim 1, characterized in that the end (15) and the two end partial branches (16) form a trapezoidal structure, and the two end partial branches (16) form a trapezoidal structure. The distance between the positions close to the end (15) is small, and the distance between the two end partial branches (16) is large at the position far from the end (15).
The new type gold semi-contact multi-bus grid single crystal high-efficiency battery according to claim 1, characterized in that a plurality of openings are arranged on the frame line (12) at intervals.
The new type gold semi-contact multi-bus grid single crystal high-efficiency battery according to claim 1, wherein the solder joint (14) is a rounded rectangular structure, and the narrow side length of the solder joint (14) is 0.6 mm±0.2mm, the width of the solder joint (14) is 1mm±0.2mm.
The new type gold semi-contact multi-bus grid single crystal high-efficiency battery according to claim 1, characterized in that the length of the gradual change section (17) is 0.6mm±0.2mm.
A new type of gold semi-contact multi-bus grid single crystal high-efficiency battery according to claim 1 or 7, characterized in that the widest value of the gradual change section (17) is 0.1±0.01 mm, and the narrowest of the gradual change section (17) The value is 0.05±0.03mm.
The new type gold semi-contact multi-bus grid single crystal high-efficiency battery according to claim 5, characterized in that the width of the space between the openings is 0.3±0.05 mm.
The new type gold half-contact multi-bus grid single crystal high-efficiency battery according to claim 1, characterized in that the distance between two adjacent main grid lines (13) is 12.4 ± 0.05 mm, and two adjacent secondary The distance between the grid lines (11) is 1.74±0.05 mm.