XBC battery piece with anti-breaking grid lines

Abstract

The utility model discloses an XBC cell sheet provided with anti-breaking grid lines, which belongs to the technical field of solar cells and comprises a plurality of P regions and N regions which are sequentially and alternately arranged, main grid lines, auxiliary grid lines and anti-breaking grid lines are arranged in the P regions and the N regions, the auxiliary grid lines are vertically connected with the main grid lines, and the anti-breaking grid lines intersect with the auxiliary grid lines and are parallel to the main grid lines. At least three auxiliary grid lines are printed in the P region or the N region, the anti-breaking grid lines are vertically connected among the three auxiliary grid lines in the same P region or N region, the auxiliary grid line in the middle and the anti-breaking grid lines form a cross-shaped and T-shaped intersection point, and the intersection point is a welding point; a GAP isolation region is arranged between the adjacent P region and N region, and the area of the GAP region is smaller than that of an isolation region of a conventional XBC structure. The beneficial effects of the utility model lie in that the plurality of auxiliary grid lines are connected through the anti-breaking grid design so as to improve the anti-risk capability; the point, intersecting with the grid line, of the anti-breaking grid structure serves as a better weldable point to provide guarantee for follow-up 0BB welding.

Description

Technical Field

[0001] This utility model belongs to the field of solar cell technology, specifically relating to an XBC solar cell with anti-breakage grid lines. Background Technology

[0002] Back-contact (XBC) cells refer to various types of crystalline silicon solar cells with back-contact structures, including IBC, HBC, PBC, ABC, MBC, and HPBC. Due to their high efficiency, which is difficult for conventional solar cells to achieve, they have attracted much attention in the industry and have become a research hotspot for next-generation solar cell technology. Because of their high efficiency, unobstructed front side, and aesthetic appeal, they are expected to become the next mainstream cell technology after PERC and TOPCon. Compared with existing TOPCon and HJT cells, the biggest feature of XBC is the absence of grid lines on the front side. The back side is no longer a simple N-region or P-region, but rather typically has staggered P and N regions fabricated on the back of the cell, integrating the positive and negative electrodes on the back. Thanks to this structure, XBC cells do not have electrode grid lines obstructing the front side, thus improving both power generation efficiency and aesthetics.

[0003] Conventional anti-breakage grid designs typically integrate the grid lines onto the sub-grid, meaning the anti-breakage grid lines and sub-grid lines are printed simultaneously. In conventional XBC structures, only a single grid line is printed for each P and N region, with adjacent P and N regions separated by gaps to prevent direct conduction between the P and N gates. Because a single grid line is relatively long, printing defects in certain areas can prevent the collected current from flowing into the main grid, thus rendering the entire grid line ineffective. In conventional XBC designs, even a single printing defect on a grid line can severely impact the current collection of the entire grid line. Furthermore, the numerous gaps separating adjacent P and N regions result in a waste of usable battery area.

[0004] Existing technologies disclose several patents for batteries with anti-grid breakage features. Among them, utility model patent CN206116430U discloses an anti-grid breakage high-efficiency monocrystalline battery, including a cell comprising a monocrystalline silicon wafer, a hydrogenated amorphous silicon thin film, and a silicon oxide anti-reflective film. The surface of the monocrystalline silicon wafer is covered with the hydrogenated amorphous silicon thin film, and the surface of the hydrogenated amorphous silicon thin film is covered with the silicon oxide anti-reflective film. Main grid lines are longitudinally distributed on the surface of the cell, and sub-grid lines are laterally distributed on the surface of the cell. Anti-grid breakage lines are vertically distributed at intervals between the sub-grid lines. Although the conversion efficiency of the monocrystalline silicon battery can be optimized and improved by adding the hydrogenated amorphous silicon thin film and the silicon oxide anti-reflective film to the surface of the monocrystalline silicon wafer, problems still exist. A printing defect on a single grid line can severely affect the current collection of the entire grid line, and there are many gaps (GAPs) blocking adjacent P and N regions, resulting in a certain waste of usable battery area.

[0005] In view of this, the inventors conducted in-depth research to address this need, which led to this case. Utility Model Content

[0006] To overcome the problems in existing technologies where poor printing on a single grid line severely impacts current collection for the entire grid line, and numerous gaps (GAPs) obstructing adjacent P and N regions lead to wasted battery area, this invention provides an XBC cell with anti-breakage grid lines. The cell includes several staggered P and N regions. Each P and N region contains a main grid line, a sub-grid line, and an anti-breakage grid line. The sub-grid lines are perpendicularly connected to the main grid lines. The anti-breakage grid lines intersect with the sub-grid lines and are parallel to the main grid lines. At least three sub-grid lines are printed within each P or N region. The anti-breakage grid line is perpendicularly connected between the three sub-grid lines in the same P or N region, with the middle sub-grid line forming a cross and a T-shaped intersection with the anti-breakage grid line. These intersections are welding points. A GAP isolation area is provided between adjacent P and N regions, and the total area of ​​the GAP isolation area is smaller than the isolation area in a conventional XBC structure.

[0007] The anti-breakage grid design connects multiple originally unconnected grid lines to improve risk resistance; the anti-breakage grid structure at the cross position where it intersects with the grid lines serves as a higher quality weldable point, providing a guarantee for subsequent 0BB welding.

[0008] Furthermore, at least two anti-breakage grid lines are provided in a single P-region or N-region, the spacing between the anti-breakage grid lines is equally distributed according to the length of the P-region and the N-region, and the width of the anti-breakage grid lines is 10~60μm.

[0009] Furthermore, the width of each of the P-regions and the N-regions is set to 8~20mm, and the anti-breakage grid line is at least located in the middle of the sub-grid line and at the tail position away from the main grid line.

[0010] Furthermore, the screen opening width of the anti-breakage grid line is 10~60μm, and the anti-breakage grid line is electrically connected to the sub-grid line through a low-corrosion silver paste material.

[0011] Furthermore, when the anti-breakage grid line is applied to OBB graphics, the main grid can be completely replaced by the anti-breakage grid line, and the solder joints are printed with high solids content silver paste.

[0012] Furthermore, the extended connecting lines of some of the anti-breakage grid lines include, but are not limited to, straight connections, broken line connections, or wavy connections, and the length of the connection path does not exceed 20% of the length of the corresponding sub-grid line.

[0013] Furthermore, the width of the sub-gate line is 10~40μm, and the density of the sub-gate line is 15~25 lines / cm. The spacing between the sub-gate lines in the same P region and N region is 0.5~1mm, and the spacing between the main gate lines in adjacent N regions of the P region is set to 8~25mm.

[0014] Furthermore, the width of the GAP isolation area is 50~150μm, and it is formed by laser etching or mask printing process.

[0015] Furthermore, the silver paste solid content of the welding point is ≥85%, and the diameter of the welding point is 10~300μm.

[0016] Furthermore, the anti-breakage grid line is a straight line or a curve, and the extension line of the anti-breakage grid line forms an angle with the sub-grid line.

[0017] The beneficial effects of adopting the technical solution of this utility model are as follows:

[0018] (1) By using the anti-breakage grid design, multiple grid lines that were originally not connected are connected, thereby improving the ability to resist risks; the anti-breakage grid structure at the cross position where it intersects with the grid lines serves as a better weldable point, providing a guarantee for subsequent 0BB welding. When the sub-grid line breaks, the anti-breakage grid line can maintain at least 80% current transmission efficiency through adjacent current guiding paths.

[0019] (2) Reduce the total GAP isolation area of ​​the entire cell, increase the effective utilization area of ​​the entire cell, further reduce the loss of the cell during laser patterning, and improve the yield of cell production.

[0020] (3) Individual P and N regions have more sub-gate lines, which allows photogenerated carriers to be collected better and more effectively before recombination, further improving the current density of the battery. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This utility model illustrates the overall structure of an XBC battery cell with anti-breakage grid lines.

[0023] Figure 2 This is a partial structural concept of an XBC battery cell with anti-breakage grid lines according to this utility model;

[0024] Figure 3 This is a cross-sectional schematic diagram of an XBC battery cell with anti-breakage grid lines according to this utility model;

[0025] In the diagram, 1 is the P area; 2 is the N area; 3 is the main grid line; 4 is the secondary grid line; 5 is the anti-breakage grid line; and 6 is the GAP isolation area. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Therefore, the following detailed description of the embodiments of this utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0027] This embodiment uses a break-resistant grid design to connect multiple originally unconnected grid lines, thereby improving resilience. The break-resistant grid structure, at the cross-shaped intersection with the grid lines, serves as a superior solderable point, ensuring a smooth OBB soldering process. Even if a secondary grid line breaks, the break-resistant grid line can maintain at least 80% current transmission efficiency through adjacent current-carrying paths. The specific implementation is as follows:

[0028] like Figures 1-3 As shown, an XBC solar cell with anti-breakage grid lines 5 includes several staggered P-regions 1 and N-regions 2. Each P-region 1 and N-region 2 is provided with a main grid line 3, a secondary grid line 4, and an anti-breakage grid line 5. The secondary grid lines 4 are perpendicularly connected to the main grid lines 3. The anti-breakage grid lines 5 intersect with the secondary grid lines 4 and are arranged parallel to the main grid lines 3. At least three secondary grid lines 4 are printed in each P-region 1 or N-region 2. The anti-breakage grid lines 5 are perpendicularly connected between the three secondary grid lines 4 in the same P-region 1 or N-region 2. The secondary grid line 4 located in the middle position forms a cross and a T-shaped intersection with the anti-breakage grid line 5. The intersection is a welding point.

[0029] A GAP isolation region 6 is provided between adjacent P region 1 and N region 2. The area of ​​the GAP isolation region 6 is smaller than that of the isolation region of a conventional XBC structure.

[0030] In a preferred embodiment, at least two anti-breakage grid lines 5 are provided in a single P region 1 or N region 2, the spacing of the anti-breakage grid lines 5 is equally distributed according to the length of the P region 1 and the N region 2, and the width of the anti-breakage grid lines 5 is 10~60μm.

[0031] Here, if the width of the anti-breakage grid line 5 is less than 10μm, it may cause abnormal ink penetration during printing, resulting in the breakage of the anti-breakage grid line 5 itself and losing its function of connecting the sub-grid line 4; at the same time, if the anti-breakage grid line 5 is too wide, it will result in excessive use of silver paste, affecting cost control.

[0032] In a preferred embodiment, the width of each of the P-region 1 and the N-region 2 is set to 8~20mm, and the anti-breakage grid line 5 is at least located in the middle of the sub-grid line 4 and at the tail position away from the main grid line 3.

[0033] Here, the original silicon wafer size currently used is generally 210mm or 183mm. Due to the requirements of MBB multi-busbar module end, the size of a single P and N region 2 is limited to the range of 8~20mm.

[0034] In a preferred embodiment, the screen opening width of the anti-breakage grid line 5 is 10~60μm, and the anti-breakage grid line 5 is electrically connected to the sub-grid line 4 through a low-corrosion silver paste material.

[0035] Here, the graphic design of the stencil is created based on the attached diagram, and the positions where the lines are drawn are the positions where the stencil needs to be opened. Therefore, the width of this stencil opening is the width that the anti-breakage grid line 5 needs to be made on the stencil.

[0036] In a preferred embodiment, when the anti-breakage grid line 5 is applied to OBB graphics, the main grid can be completely replaced by the anti-breakage grid line 5, and the solder joints are printed with high solids content silver paste.

[0037] Here, when applied to the 0BB graphic, all main grid lines 3 can be replaced with anti-breakage grid lines 5, which are printed with the corresponding sub-grid lines 4 paste in P area 1 and N area 2 respectively. At the same time, the intersection of the anti-breakage grid lines 5 and the sub-grid lines 4 is used as the welding point for welding.

[0038] In a preferred embodiment, the extended connecting lines of some of the anti-breakage grid lines 5 include, but are not limited to, straight connections, broken line connections or wavy connections, and the length of the connection path does not exceed 20% of the length of the corresponding sub-grid line 4.

[0039] In a preferred embodiment, the width of the sub-gate line 4 is 10~40μm, and the density of the sub-gate line 4 is 15~25 lines / cm. The spacing between the sub-gate lines 4 in the same P region 1 and N region 2 is 0.5~1mm, and the spacing between the main gate lines 3 in adjacent N region 2 of P region 1 is set to 8~25mm.

[0040] In a preferred embodiment, the width of the GAP isolation region 6 is 50~150μm, and it is formed by laser etching or mask printing.

[0041] Here, if the GAP isolation area 6 is too narrow, it will not be able to isolate the P and N regions 2, and the leakage of the solar cell will be relatively large. If it is too wide, it will waste the effective area of ​​the solar cell. Therefore, the width of the GAP isolation area 6 is limited to 50~150μm.

[0042] In a preferred embodiment, the silver paste solid content of the welding point is ≥85%, and the diameter of the welding point is 10~300μm.

[0043] Here, when designing for 0BB without a main gate, the welding position is the point where the secondary gate and the anti-breakage gate line 5 intersect. This point is the intersection of two lines with a width of 10~30μm.

[0044] In a preferred embodiment, the anti-breakage grid line 5 is a straight line or a curve, and the extension line of the anti-breakage grid line 5 forms an angle with the sub-grid line 4.

[0045] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An XBC battery sheet provided with a breakage prevention grid line, characterized by, It includes several P-areas (1) and N-areas (2) arranged alternately in sequence. Each of the P-areas (1) and N-areas (2) is provided with a main grid line (3), a secondary grid line (4), and a breakage prevention grid line (5). The secondary grid line (4) is perpendicularly connected to the main grid line (3). The breakage prevention grid line (5) intersects with the secondary grid line (4) and is arranged parallel to the main grid line (3). At least three secondary grid lines (4) are printed in the P-area (1) or N-area (2). The breakage prevention grid line (5) is perpendicularly connected between the three secondary grid lines (4) in the same P-area (1) or N-area (2). The secondary grid line (4) located in the middle position forms a cross and a T-shaped intersection with the breakage prevention grid line (5). The intersection is a welding point. A GAP isolation area (6) is provided between adjacent P-areas (1) and N-areas (2). The total area of ​​the GAP isolation area (6) is smaller than the isolation area of ​​the XBC structure.

2. The XBC battery sheet with anti-breaking grid lines according to claim 1, characterized in that, At least two anti-breakage grid lines (5) are provided in a single P area (1) or N area (2). The spacing of the anti-breakage grid lines (5) is equally distributed according to the length of the P area (1) and the N area (2). The width of the anti-breakage grid lines (5) is 10~60μm.

3. The XBC battery sheet with anti-breaking grid lines according to claim 1, characterized in that, The width of each of the P region (1) and the N region (2) is set to 8~20mm, and the anti-breakage grid line (5) is at least located in the middle of the sub-grid line (4) and at the tail position away from the main grid line (3).

4. The XBC battery sheet with anti-breaking grid lines according to claim 1, wherein, The screen opening width of the anti-breakage grid line (5) is 10~60μm, and the anti-breakage grid line (5) is electrically connected to the sub-grid line (4) through a low-corrosion silver paste material.

5. The XBC battery sheet with anti-breaking grid lines according to claim 1, wherein, When the anti-breakage grid line (5) is applied to the OBB pattern, the main grid can be completely replaced by the anti-breakage grid line (5), and the solder joints are printed with high solids content silver paste.

6. The XBC battery sheet with anti-breaking grid lines according to claim 1, wherein, The extended connecting lines of some of the anti-breakage grid lines (5) include, but are not limited to, straight connections, broken line connections or wavy connections, and the length of the connection path does not exceed 20% of the length of the corresponding sub-grid line (4).

7. The XBC battery sheet with anti-breaking grid lines according to claim 1, wherein, The width of the sub-gate line (4) is 10~40μm, and the density of the sub-gate line (4) is 15~25 lines / cm. The spacing between the sub-gate lines (4) in the same P region (1) and N region (2) is 0.5~1mm. The spacing between the main gate lines (3) in the adjacent N region (2) of the P region (1) is set to 8~25mm.

8. The XBC battery sheet with anti-breaking grid lines according to claim 1, wherein, The width of the GAP isolation area (6) is 50~150μm, and it is formed by laser etching or mask printing process.

9. The XBC battery sheet with anti-breaking grid lines according to claim 5, wherein, The silver paste at the welding point has a solid content of ≥85% and a diameter of 10~300μm.

10. The XBC battery sheet with anti-breaking grid lines according to claim 1, wherein, The anti-breakage grid line (5) is a straight line or a curve, and the extension line of the anti-breakage grid line (5) forms an angle with the sub-grid line (4).

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