Solar energy battery

Abstract

A patterned passivation contact structure and a back electrode located on the passivation contact structure are arranged on the back face of the solar cell, the passivation contact structure is provided with a hollowed-out area located in a non-grid line area, and the distance between the hollowed-out area and the back electrode is not smaller than 50 micrometers. According to the utility model, the non-grid line area of the passivation contact structure is provided with the hollow area, so that the doped polycrystalline silicon layer in the non-grid line area is removed, the parasitic absorption effect on light is reduced, and the efficiency of the cell is improved; furthermore, the distance from the hollow area to the back electrode is designed to be not less than 50 microns, so that an enough interval between the hollow area and the back electrode is ensured, damage to the grid line area during slotting of the hollow area is avoided, and burn-through type electrode slurry is also prevented from expanding to the hollow area to influence the passivation performance of the battery piece.

Description

Technical Field

[0001] The utility model relates to the photovoltaic field, in particular to a solar cell capable of improving back light utilization rate under the premise of ensuring back passivation performance. Background Art

[0002] In recent years, the market share of TOPCon (Tunnel Oxide Passivated Contact) solar cells has risen rapidly and has gradually become the mainstream technology of solar cells. The back of the TOPCon cell has a passivation contact structure composed of a tunneling oxide layer and a doped polysilicon layer, which improves the passivation performance of the back and is compatible with traditional industrial production, and has broad development prospects.

[0003] However, the back-doped polysilicon layer produces parasitic absorption of light, which reduces the utilization of light and affects the light utilization on the back of the cell and the cell efficiency.

[0004] In view of this, it is necessary to provide an improved solar cell to solve the above technical problems. Utility Model Content

[0005] The utility model aims to solve at least one of the technical problems existing in the prior art, and provides a solar cell.

[0006] In order to achieve one of the above-mentioned purposes of the utility model, the utility model adopts the following technical solutions:

[0007] A solar cell has a patterned passivation contact structure and a back electrode on the passivation contact structure. The passivation contact structure has a hollow area in a non-gridline area, and the distance from the hollow area to the back electrode is not less than 50 μm.

[0008] Optionally, the back electrode includes a plurality of main grids extending along a first direction, ends of the main grids have a harpoon structure, and the hollow area is located outside the harpoon structure.

[0009] Optionally, the back electrode includes a plurality of main grids extending along the first direction, the ends of the main grids have a harpoon structure, and the distance from the hollow area to the harpoon structure is 50 μm to 200 μm.

[0010] Optionally, the back electrode includes a plurality of sub-grids arranged along a first direction, the sub-grids extend along a second direction perpendicular to the first direction, and the length of the hollow region in the second direction is smaller than the length of the sub-grids.

[0011] Optionally, a distance from an end of the hollow area in the second direction to an end of the auxiliary grid is not less than a distance from the hollow area to the auxiliary grid in the first direction.

[0012] Optionally, the distance from the hollow area to the edge of the battery is not less than 300 μm.

[0013] Optionally, the back electrode includes a frame grid line arranged along an edge of the silicon substrate, and the hollow area is located inside the frame grid line.

[0014] Optionally, the distance from the hollow area at the chamfer to the edge of the battery is not less than the distance from the hollow area at the non-chamfer to the edge of the battery.

[0015] A solar cell has a patterned passivation contact structure and a back electrode on the passivation contact structure on its back side. The passivation contact structure is only located in the gate line area, and the distance from the back electrode to at least part of the edge of the passivation contact structure is not less than 50 μm.

[0016] Optionally, the back electrode includes several main grids extending along the first direction, the ends of the main grids have a harpoon structure, and the harpoon structure is entirely located on the passivation contact structure. Preferably, the distance from the harpoon structure to the edge of the passivation contact structure is 50μm to 200μm.

[0017] Optionally, the back electrode includes a frame grid line, and the passivation contact structure located below the frame grid line extends outward to the edge of the battery.

[0018] The beneficial effects of the utility model are as follows: the utility model sets a hollow area in the non-gate line area of ​​the passivation contact structure, thereby removing the doped polysilicon layer in the non-gate line area, reducing the parasitic absorption of light and improving the efficiency of the battery; further, the distance from the hollow area to the back electrode is designed to be no less than 50μm, ensuring that the hollow area and the back electrode have sufficient spacing, avoiding damage to the gate line area when the hollow area is grooved, and also avoiding the burn-through electrode slurry from expanding to the hollow area to affect the passivation performance of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of a solar cell in a preferred embodiment of the utility model;

[0020] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0021] Figure 3 for Figure 1 A partial enlarged view of point B in the middle.

[0022] Among them, 100 is a solar cell, 1 is a back electrode, 11 is a main grid, 12 is a secondary grid, 13 is a frame grid line, 2 is a passivation contact structure, and 20 is a hollow area. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0024] In the various drawings of the present invention, for the convenience of illustration, some dimensions of structures or parts are exaggerated relative to other structures or parts, and therefore, are only used to illustrate the basic structure of the subject matter of the present invention.

[0025] The inventors have found that by opening the doped polysilicon layer on the back of the TOPCon battery and removing the doped polysilicon layer in the non-gateline area, the parasitic absorption of light by the layer can be avoided; only the tunneling oxide layer and the doped polysilicon layer in the gateline area are retained to isolate the direct contact between the metal gateline and the silicon substrate, thereby reducing metal recombination; the efficiency of the battery can be improved. However, in order to improve the efficiency of the battery, the larger the area of ​​laser opening on the back side, the better, but this can easily damage the passivation performance of the back side. To this end, the utility model aims to provide a solar cell 100 that removes the doped polysilicon layer from the largest area without damaging the passivation performance of the back side and reducing the damage to the silicon substrate caused by grooving, thereby achieving the purpose of improving the efficiency and bifaciality of the battery cell.

[0026] Please refer to Figure 1 to Figure 3 As shown, a solar cell 100 of a preferred embodiment of the utility model is provided with a patterned passivation contact structure 2 and a back electrode 1 located on the passivation contact structure 2 on the back side. The passivation contact structure 2 has a hollow area 20 located in the non-gate line area.

[0027] The "hollow area 20" of the present invention refers to the area without doped polysilicon layer, which can also be understood as the removal of doped polysilicon layer in the non-gate line area, thereby reducing the parasitic absorption of light and improving the efficiency of the battery.

[0028] The back electrode 1 includes a plurality of main grids 11 extending along a first direction, and a plurality of auxiliary grids 12 arranged along the first direction, wherein the auxiliary grids 12 extend along a second direction perpendicular to the first direction, and the plurality of auxiliary grids 12 are arranged in parallel. Preferably, the back electrode 1 also includes a frame grid line 13 arranged along the edge of the battery, and the main grid 11 and the auxiliary grid 12 are both located within the frame grid line 13 and connected to the frame grid line 13.

[0029] In the present invention, the distance from the hollow area 20 to the back electrode 1 is not less than 50μm, preferably 50μm to 500μm, and more preferably 50μm to 200μm, to ensure that the hollow area 20 and the back electrode 1 have sufficient spacing and are not in contact with each other; thereby avoiding damage to the gate line area when the hollow area 20 is grooved, and also avoiding the burn-through electrode slurry from expanding to the hollow area 20 to affect the passivation performance of the battery.

[0030] Specifically, the end of the main grid 11 has a harpoon structure, and the hollow area 20 is located outside the harpoon structure. Even if the middle area of ​​the harpoon structure is hollowed out without grid lines, the passivation contact structure 2 is set in the middle area, which fully ensures the passivation effect where the harpoon structure is located, and avoids the grooves in the hollow area 20 from causing damage to the area where the harpoon structure is located.

[0031] Optionally, the distance from the hollow area to the harpoon structure is 50 μm to 200 μm. On the basis of ensuring the spacing between the hollow area and the gate line, the polysilicon layer in the non-gate line area is removed to the maximum extent, thereby improving the battery efficiency.

[0032] In the second direction, the length of the hollow area 20 is less than the length of the auxiliary grid 12, that is, the area where the end of the auxiliary grid 12 is located is not grooved, and even if the auxiliary grid 12 is deflected due to printing errors, it will not contact the hollow area 20, thereby fully ensuring the passivation performance at the end of the auxiliary grid 12.

[0033] In one embodiment, the length of the hollow region 20 is 800 μm to 1000 μm shorter than the length of the secondary gate 12 .

[0034] Taking into account that the degree of damage to the edge and the middle area of ​​the battery in the battery manufacturing process is slightly different, the photoelectric conversion performance of the two areas is slightly different. The distance from the end of the hollow area 20 in the second direction to the end of the auxiliary grid 12 is not less than the distance from the hollow area 20 to the auxiliary grid 12 in the first direction. The arrangement density of the hollow area 20 in the middle of the battery is higher than the arrangement density at the edge of the battery, which ensures that there is a sufficiently large hollow area in the middle and improves the light utilization rate; it also ensures the passivation effect of the battery edge, reduces the chance of damage to the edge, and improves the battery performance as a whole.

[0035] Furthermore, the distance from the hollow area 20 to the edge of the battery is not less than 300 μm, which reduces the impact of laser film opening on the edge of the battery and does not affect the leakage and JO2 of the battery cell.

[0036] In the embodiment where the back electrode 1 also includes a frame grid line 13, the hollow area 20 is located inside the frame grid line 13, that is, no laser grooving is performed outside the frame grid line 13, thereby reducing damage to the edge caused by grooving and ensuring the passivation effect at the edge.

[0037] Preferably, the distance from the hollow area 20 at the chamfer to the edge is not less than the distance from the hollow area 20 at the non-chamfer to the edge. The length of the hollow area 20 at the chamfer is shorter than that of the hollow area 20 in the middle area, with a difference of 800-1000 μm.

[0038] The utility model also provides another solar cell 100, on the back of which a patterned passivation contact structure 2 and a back electrode 1 located on the passivation contact structure 2 are provided. The passivation contact structure 2 is only located in the gate line area, and the doped polysilicon layer in the non-gate line area is removed to avoid its parasitic absorption of light and improve the cell efficiency.

[0039] The arrangement of the back electrode 1 is as described above and will not be repeated here. Preferably, the distance from the back electrode 1 to at least part of the edge of the passivation contact structure 2 is not less than 50 μm, preferably 50 μm to 500 μm, more preferably 50 μm to 200 μm, and the width and length of the passivation contact structure 2 are both greater than the back electrode 1, ensuring that the back electrode 1 is always located on the passivation contact structure 2 and does not directly contact the silicon substrate, reducing metal recombination and improving the efficiency of the battery.

[0040] The end of the main grid 11 has a harpoon structure, and the harpoon structure is entirely located on the passivation contact structure 2. Even if the middle area of ​​the harpoon structure is hollowed out without grid lines, the passivation contact structure 2 is set in the middle area, which fully ensures the passivation effect where the harpoon structure is located.

[0041] Preferably, the distance from the harpoon structure to the edge of the passivation contact structure is 50 μm to 200 μm; on the premise of ensuring a good passivation effect at the harpoon, the doped polysilicon in the non-gate line area is removed to the maximum extent to improve the utilization rate of light.

[0042] In the embodiment where the back electrode 1 includes a frame grid line 13, the passivation contact structure 2 located below the frame grid line 13 extends outward to the edge of the battery, that is, no laser grooving is performed outside the frame grid line 13, thereby reducing damage to the edge caused by the grooving and ensuring the passivation effect at the edge.

[0043] In summary, the utility model sets a hollow area 20 in the non-gate line area of ​​the passivation contact structure 2, removes the doped polysilicon layer in the non-gate line area, reduces the parasitic absorption of light, and improves the efficiency of the battery; further, the distance from the hollow area 20 to the back electrode 1 is designed to be no less than 50μm, ensuring that there is sufficient spacing between the hollow area 20 and the back electrode 1, avoiding damage to the gate line area when the hollow area 20 is grooved, and also avoiding the burn-through electrode slurry from spreading to the hollow area 20 to affect the passivation performance of the battery cell.

[0044] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0045] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the utility model. They are not intended to limit the protection scope of the utility model. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A solar cell having a patterned passivation contact structure on its back and a back electrode on the passivation contact structure. It is characterized in that The passivation contact structure has a hollow region located in a non-gate line region, and a distance from the hollow region to at least a portion of the back electrode is not less than 50 μm.

2. The solar cell according to claim 1, Features: The back electrode includes a plurality of main grids extending along a first direction, the ends of the main grids have a harpoon structure, and the hollow area is located outside the harpoon structure.

3. The solar cell according to claim 2, Features: The distance from the hollow area to the harpoon structure is 50 μm to 200 μm.

4. The solar cell according to claim 1, Features: The back electrode includes a plurality of sub-grids arranged along a first direction, wherein the sub-grids extend along a second direction perpendicular to the first direction, and the length of the hollow area in the second direction is smaller than the length of the sub-grids; and / or the distance from the end of the hollow area in the second direction to the end of the sub-grid is not smaller than the distance from the hollow area to the sub-grid in the first direction.

5. The solar cell according to any one of claims 1 to 4, Features: The distance from the hollow area to the edge of the battery is not less than 300 μm.

6. The solar cell according to claim 5, Features: The back electrode comprises a frame grid line arranged along the edge of the silicon substrate, and the hollow area is located inside the frame grid line.

7. The solar cell according to claim 5, Features: The distance from the hollow area at the chamfer to the edge of the battery is not less than the distance from the hollow area at the non-chamfer to the edge of the battery.

8. A solar cell having a patterned passivation contact structure on its back and a back electrode on the passivation contact structure. Features: The passivation contact structure is only located in the gate line region, and the distance from the back electrode to at least a portion of the edge of the passivation contact structure is not less than 50 μm.

9. The solar cell according to claim 8, Features: The back electrode includes a plurality of main grids extending along a first direction, the ends of the main grids have a harpoon structure, the harpoon structure is entirely located on the passivation contact structure, or the distance from the harpoon structure to the edge of the passivation contact structure is 50 μm to 200 μm.

10. The solar cell according to claim 8, Features: The back electrode includes a frame grid line, and the passivation contact structure located below the frame grid line extends outward to the edge of the battery.

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