Grid line structure of main-grid-free solar cell

Abstract

The utility model discloses a main-grid-free solar cell grid line structure, which comprises a first fine grid and a second fine grid which are positioned on two sides of a welding strip and are perpendicular to the welding strip, a vertical distance A is formed between the first fine grid and the second fine grid in the vertical direction, a transverse distance B is formed between the inner side end points of the first fine grid and the second fine grid in the transverse direction, and the first fine grid and the second fine grid are parallel to each other. The transverse distance B is not larger than the diameter b of the welding strip, and the inner end points of the first fine grid and the second fine grid are connected with the welding strip. The fine grid pattern of the main-grid-free solar cell is optimized, so that the contact point positions of the welding strip and the fine grid are multiplied, the bonding force between the welding strip and the cell can be ensured by connecting the grid line and the welding strip only in a welding mode, the problem that the welding strip is easy to separate from the grid is solved, the reliability of the module is improved, dispensing connection is not needed, the cell manufacturing steps are shortened, and the production cost is reduced. Therefore, the problem of component EL blackening caused by shielding of the insulating glue on the grid line during dispensing is avoided, the current collection capability of the solder strip is improved, the component power is further improved, and the cost of the component is reduced.

Description

Technical Field

[0001] The utility model relates to a grid line structure of a solar cell, in particular to a grid line structure of a solar cell without a main grid. Background Art

[0002] With the update and iteration of photovoltaic cell technology, N-type cells have gradually replaced PERC cells and become the mainstream. However, the silver paste consumption of TOPCon cells and HJT cells is relatively high. In order to further reduce the silver paste consumption, researchers have proposed many cost reduction technologies, such as silver-clad copper, 0BB, copper electroplating and other technologies. Among them, 0BB technology has been widely studied by researchers because of its busbar-free design, which can greatly reduce the cost of silver paste. Some companies have now entered the mass production stage.

[0003] At present, the main ways to implement 0BB technology are SmartWire, glue dispensing, and welding first and then glue dispensing. SmartWire has a high cost and there are patent barriers; glue dispensing is to print glue on the battery cell to make the soldering tape and the battery cell bonded, and then achieve alloying after lamination, but there is a problem of insufficient bonding between the soldering tape and the battery cell; welding first and then glue dispensing has more process steps, and glue dispensing may cover the metal grid line and EL blackening. Glue dispensing can improve the tension between the soldering tape and the battery cell, but the glue used is insulating glue. If the glue dispensing position deviates from the set position and covers the fine grid, it will reduce the collection of current, which will affect the power of the component. Utility Model Content

[0004] Purpose of the utility model: The purpose of the utility model is to provide a grid line structure of a main grid solar cell without a main grid, which can meet the bonding force between the welding strip and the battery cell without falling off the grid through welding and without the need for glue.

[0005] Technical solution: A busbar-free solar cell grid line structure, comprising a first fine grid and a second fine grid located on both sides of a welding strip and both perpendicular to the welding strip, the first fine grid and the second fine grid having a vertical spacing A in the vertical direction, the inner end points of the first fine grid and the second fine grid having a lateral spacing B in the lateral direction, the lateral spacing B being no greater than a diameter b of the welding strip, and the inner end points of the first fine grid and the second fine grid both being connected to the welding strip.

[0006] Preferably, the first fine grid and the second fine grid have the same size.

[0007] Furthermore, a plurality of first fine grids are arranged on the same side of the welding strip, and the plurality of first fine grids are arranged with gaps in the vertical direction.

[0008] Optimally, a plurality of first fine grids are arranged at equal intervals in the vertical direction, and the vertical interval A is 1 / 2 of the interval between adjacent first fine grids.

[0009] Furthermore, a plurality of second fine grids are arranged on the same side of the welding strip, and the plurality of second fine grids are arranged at intervals in the vertical direction.

[0010] Optimally, the plurality of second fine grids are arranged at equal intervals in the vertical direction, and the vertical interval A is 1 / 2 of the interval between adjacent second fine grids.

[0011] Preferably, the inner end points of the first fine grid and the second fine grid are connected to the welding strip by welding.

[0012] Furthermore, the vertical spacing A is 1 to 2 mm.

[0013] Beneficial effect: The advantages of the utility model are: the fine grid pattern is optimized for the main grid solar cell without main grid, so the contact points between the welding strip and the fine grid are multiplied, and the bonding strength between the welding strip and the battery cell can be ensured only by connecting the grid line and the welding strip by welding, thereby improving the problem of the welding strip easily coming off the grid, improving the reliability of the component, and eliminating the need for glue dispensing connection, and eliminating the steps of introducing colloid, printing glue screen, glue dispensing, curing colloid and fixtures. The battery manufacturing steps are greatly shortened, and the problem of blackening of the component EL caused by the insulating glue blocking the grid line during glue dispensing is avoided, and the ability of the welding strip to collect current is improved, thereby increasing the power of the component, which helps to reduce the cost of the component. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the fine grid pattern and the layout position of the welding ribbon of a conventional busbar-free solar cell;

[0015] Figure 2 A schematic diagram of the fine grid pattern and the layout position of the welding ribbon of the busbar-free solar cell of the present application;

[0016] Figure 3 This is an exploded diagram of the dimensional relationship between the first fine grid, the second fine grid, and the welding strip. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with specific embodiments.

[0018] A busbar-free solar cell grid line structure, as shown in the attached Figure 2 As shown, it includes a first fine grid 1 and a second fine grid 2. The first fine grid 1 and the second fine grid 2 are respectively located on both sides of the welding strip 3 in the vertical direction and are perpendicular to the welding strip 3. The first fine grid 1 and the second fine grid 2 are in the horizontal direction, but the two are not flush. Figure 3As shown, the first fine grid 1 and the second fine grid 2 have a vertical spacing A in the vertical direction, and the vertical spacing A is 1 to 2 mm, and the inner end point 11 of the first fine grid 1 and the inner end point 21 of the second fine grid 2 have a lateral spacing B in the lateral direction, and the lateral spacing B is equal to or less than the welding strip diameter b, so that the first fine grid 1 is directly connected to the welding strip 3 with its inner end point 11 and the second fine grid 2 is directly connected to the welding strip 3 with its inner end point 21, thereby ensuring that the welding strip is completely connected to the fine grid, thereby increasing the tension between the welding strip and the battery cell, and improving the carrier collection capacity.

[0019] It can be seen that the fine grids on the busbar-free solar cell of the present application are arranged in sections on both sides of the welding strip, and the width and length of the first fine grid and the second fine grid can be the same or different.

[0020] A plurality of first fine grids 1 are arranged on one side of the welding strip, and the plurality of first fine grids are arranged at intervals in the vertical direction, preferably at equal intervals. A plurality of second fine grids 2 are arranged on the other side of the welding strip, and the plurality of second fine grids are arranged at intervals in the vertical direction, preferably at equal intervals. Preferably, the vertical spacing A is 1 / 2 of the gap between two adjacent first fine grids, that is, the second fine grid is aligned at the midpoint between two adjacent first fine grids in the horizontal direction, and the vertical spacing A is 1 / 2 of the gap between two adjacent second fine grids, that is, the first fine grid is aligned at the midpoint between two adjacent second fine grids in the horizontal direction.

[0021] The fine grid pattern of the present application can be formed on the battery cell by screen printing using a screen plate. The number of fine grids in the fine grid pattern can be designed and set according to needs, and there is no restriction on the type of battery used for the fine grid pattern.

[0022] At the component end, the inner end point of the first fine grid, the inner end point of the second fine grid and the welding strip are connected by welding.

[0023] Depend on Figure 1 The local area I in Figure 2It is more obvious in the local area II in the figure: when the conventional fine grid pattern is used, there are only 7 contact points between the welding ribbon and the battery cell (i.e., the contact points between the welding ribbon and the fine grid). Since the battery cell is designed without a main grid, the bonding force between the welding ribbon and the battery cell may be insufficient, resulting in grid detachment. When welding at the component end, glue is needed to further fix the welding ribbon and the battery cell after the fine grid is welded to the welding ribbon to compensate for the problem of insufficient welding tension. However, after glue is dispensed, the glue dispense position may deviate from the original set position and cover the fine grid. In addition, the glue is an insulating glue, which will greatly increase the contact resistance here, which will weaken the current collection ability here, thereby causing the photovoltaic module to work poorly. The rate decreases; when the fine grid pattern of the present application is adopted, there are 14 contact points between the welding ribbon and the battery cell, which is twice that of the conventional fine grid pattern, which is sufficient to ensure the bonding strength between the welding ribbon and the battery cell. At the component end, only the grid line and the welding ribbon are connected by welding to fix the welding ribbon, which helps to improve the problem of easy detachment of the welding ribbon, and solves the problem of insufficient bonding strength between the welding ribbon and the battery cell in the main grid solar cell. The steps of introducing colloid, printing glue screen, dispensing glue, curing colloid and fixtures can be omitted, and the battery manufacturing steps are greatly shortened, which solves the problem of blackening of the component EL caused by the insulating glue, improves the ability of the welding ribbon to collect current, and helps to reduce the cost of the component.

[0024] The process of making batteries by welding at the component end: (1) Selecting battery cells; (2) Wiring: Arrange the welding strips vertically along the end points of each group of fine grids, and multiple welding strips are arranged on the battery cells; (3) Welding: Use infrared contact welding to weld the fine grid end points to the welding strips, and weld the battery cells and welding strips into strings; (4) Layout: Arrange multiple battery strings to form components; (5) Lamination: Put the laid-out components into the laminator, and the adhesive film will melt under certain conditions to bond the components, glass, and backplane together; (6) Framing: Assemble the aluminum frame and junction box of the component with silicone on the laminate; (7) Test packaging. In this production process, you can also apply glue on the welding strip after welding to enhance the adhesion of the welding strip in the interlayer component. At this time, it is necessary to pay attention to the glue application position so that it does not cover the fine grid.

Claims

1. A busbar-free solar cell grid line structure, characterized in that: It includes a first fine grid and a second fine grid located on both sides of the welding strip and both perpendicular to the welding strip, the first fine grid and the second fine grid have a vertical spacing A in the vertical direction, the inner end points of the first fine grid and the second fine grid have a transverse spacing B in the transverse direction, the transverse spacing B is not greater than the diameter b of the welding strip, and the inner end points of the first fine grid and the second fine grid are both connected to the welding strip.

2. The busbar-free solar cell grid line structure according to claim 1, characterized in that: The first fine grid and the second fine grid have the same size.

3. The busbar-free solar cell grid line structure according to claim 1 or 2, characterized in that: A plurality of first fine grids are arranged on the same side of the welding strip, and the plurality of first fine grids are arranged at intervals in the vertical direction.

4. The busbar-free solar cell grid line structure according to claim 3, characterized in that: A plurality of first fine grids are arranged at equal intervals in the vertical direction.

5. The busbar-free solar cell grid line structure according to claim 1 or 2, characterized in that: A plurality of second fine grids are arranged on the same side of the welding strip, and the plurality of second fine grids are arranged at intervals in the vertical direction.

6. The busbar-free solar cell grid line structure according to claim 5, characterized in that: A plurality of second fine grids are arranged at equal intervals in the vertical direction.

7. The busbar-free solar cell grid line structure according to claim 1, characterized in that: The inner end points of the first fine grid and the second fine grid are connected to the welding strip by welding.

8. The busbar-free solar cell grid line structure according to claim 1, characterized in that: The vertical spacing A is 1 to 2 mm.

9. The busbar-free solar cell grid line structure according to claim 4, characterized in that: The vertical spacing A is 1 / 2 of the gap between adjacent first fine grids.

10. The busbar-free solar cell grid line structure according to claim 6, characterized in that: The vertical spacing A is 1 / 2 of the gap between adjacent second fine grids.

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