TOPCon solar cell and cell assembly

Abstract

The invention relates to a TOPCon solar cell and a cell assembly, a plurality of removal parts and non-removal parts are arranged on the back of a silicon substrate of the TOPCon solar cell at intervals, and the non-removal parts are provided with back metal electrodes; the back metal electrode comprises a plurality of fine grids which extend along the first direction on the back passivation layer and are arranged along the second direction; and the distance X between the two adjacent fine grids and the proportion Y of the width of the non-removed part in the second direction to the distance between the two adjacent fine grids meet the following condition:-0.00002 X + 0.1240 < Y <-0.00050 X + 1.2067. According to the invention, the poly layer is removed by thinning the back part region which is not in contact with the metal electrode, and meanwhile, the proportion of the width of the N + region to the distance between the fine grids is limited, so that the light absorption problem caused by the too thick poly layer can be reduced, and the excellent electrical performance of the cell can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and particularly relates to a TOPCon solar cell and a battery module with good electrical performance. Background Art

[0002] Tunnel Oxide Passivating Contacts (TOPCon) cells, also known as TOPCon cells, are a type of solar cell that uses an ultra-thin oxide layer as a passivation layer structure. Among them, in the structure of an N-type TOPCon cell, the substrate is N-type Si, a P+ doped layer is obtained on the front surface by B diffusion, and a corresponding AlOx / SiNx passivation dielectric film is deposited on the front surface by ALD or PECVD; a tunneling oxide layer and polysilicon are deposited on the back surface by LPCVD, and an N+ doped layer is obtained by in-situ P doping or intrinsic P diffusion; metal electrodes corresponding to the front and back surfaces are usually obtained by screen printing.

[0003] However, for the current mainstream TOPCon solar cell preparation technology to pursue high efficiency, a method of constructing a relatively thick poly layer is generally adopted. Although a relatively thick poly layer helps to improve the cell performance to a certain extent, it also brings problems such as excessive optical parasitic absorption and current loss. At the same time, the arrangement of the grid lines will also affect the cell performance. Summary of the Invention

[0004] In view of the above technical problems, the present invention provides a TOPCon solar cell and a battery module. The present invention adopts the following technical solutions:

[0005] A TOPCon solar cell includes a silicon substrate. On the front surface of the silicon substrate, a boron-doped layer, a front passivation layer, and a front metal electrode are arranged along the direction away from the silicon substrate, and the front metal electrode is in ohmic contact with the boron-doped layer;

[0006] On the back surface of the silicon substrate, a plurality of removal parts and non-removal parts are arranged at intervals along a first direction. A back passivation layer is arranged on the removal part, and a tunneling oxide layer, a conductive passivation layer, a back passivation layer, and a back metal electrode are arranged on the non-removal part along the direction away from the silicon substrate. The back metal electrode is in ohmic contact with the conductive passivation layer;

[0007] The back metal electrode includes a plurality of fine grids extending along the first direction and arranged in a row along a second direction on the back passivation layer;

[0008] The TOPCon solar cell satisfies:

[0009] -0.00002X + 0.1240 < Y < -0.00050X + 1.2067;

[0010] Wherein, X is the distance between two adjacent fine grids, with the unit of μm;

[0011] Y is the ratio of the width of the non-removal part along the second direction to the distance between two adjacent fine grids.

[0012] Further, the distance X between two adjacent fine grids and the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent fine grids satisfy: -0.00007X + 0.3209 < Y < -0.00041X + 1.0098.

[0013] Further, the distance X between two adjacent fine grids is 500 μm to 1300 μm, the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent fine grids is 14.1% to 74.7%, and the width Z of the non-removal part along the second direction is 130 μm to 720 μm.

[0014] Further, the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent fine grids is 27.8% to 58.2%, and the width Z of the non-removal part along the second direction is 280 μm to 600 μm.

[0015] Further, the conductive passivation layer is a phosphorus-doped polysilicon layer or a stacked polysilicon layer doped with phosphorus and containing a silicon oxide layer; the stacked polysilicon layer containing a silicon oxide layer can be a structure of polysilicon layer + silicon oxide layer + polysilicon layer.

[0016] On the other hand, the present invention also provides a battery module, including the above-mentioned TOPCon solar cell.

[0017] Further, the back metal electrode further includes a plurality of main grids extending along the second direction and arranged in a row along the first direction, and the intersection positions of the fine grids and the main grids are connected through interconnection bars along the second direction.

[0018] Further, the fine grid includes a disconnected first fine grid and a second fine grid along the first direction, the main grids are spaced apart along the second direction, the first fine grid and the second fine grid are connected through the main grids, and the distance between the first fine grid and the second fine grid is less than the width of the interconnection bar at the contact positions of the first fine grid and the second fine grid.

[0019] Further, the main grid includes an intermediate region and end regions, the first fine grid and the second fine grid are respectively connected to the two end regions of the main grid, and the width of the intermediate region along the second direction is greater than the width of the end regions.

[0020] The TOPCon solar cell of the present invention thins and removes the poly layer from a partial area on the back that does not contact the metal electrode, and at the same time limits the ratio of the width of the non-removal part (N+ region) in contact with the metal electrode to the distance between the fine grids, which can not only improve the light transmittance of the solar cell and reduce the light absorption problem caused by the too thick poly layer, but also ensure that the cell has excellent electrical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is a schematic structural diagram of the TOPCon solar cell of the present invention;

[0023] Figure 2 It is a schematic partial back structure diagram of the TOPCon solar cell of the present invention (without connecting the interconnection bar);

[0024] Figure 3 It is another schematic partial back structure diagram of the TOPCon solar cell of the present invention (without connecting the interconnection bar);

[0025] Figure 4 It is a schematic partial back structure diagram of the battery module of the present invention (connected with the interconnection bar);

[0026] Figure 5 It is yet another schematic partial back structure diagram of the TOPCon solar cell of the present invention (without connecting the interconnection bar);

[0027] In the figure: 1 - silicon substrate, 2 - boron-doped layer, 3 - front passivation layer, 4 - front metal electrode, 5 - removal part, 6 - non-removal part, 7 - back passivation layer, 8 - tunneling oxide layer, 9 - conductive passivation layer, 10 - back metal electrode, 11 - main grid, 12 - fine grid, 13 - first fine grid, 14 - second fine grid, 15 - intermediate region, 16 - end region, 17 - interconnection bar. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following will combine the embodiments in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0029] A TOPCon solar cell, as Figure 1-2 shown, includes a silicon substrate 1. On the front side of the silicon substrate 1, a boron-doped layer 2, a front passivation layer 3, and a front metal electrode 4 are arranged in a direction away from the silicon substrate. The front metal electrode 4 is in ohmic contact with the boron-doped layer 2;

[0030] On the back side of the silicon substrate 1, a plurality of removal portions 5 and non-removal portions 6 are arranged at intervals in a second direction. A back passivation layer 7 is provided on the removal portion 5. On the non-removal portion 6, a tunneling oxide layer 8, a conductive passivation layer 9, a back passivation layer 7, and a back metal electrode 10 are arranged in a direction away from the silicon substrate 1. The back metal electrode 10 is in ohmic contact with the conductive passivation layer 9;

[0031] The back metal electrode 10 includes a plurality of fine grids 12 extending in a first direction and arranged in a second direction on the back passivation layer 7;

[0032] The TOPCon solar cell satisfies:

[0033] -0.00002X + 0.1240 < Y < -0.00050X + 1.2067;

[0034] wherein, X is the distance between two adjacent fine grids, with the unit of μm;

[0035] Y is the ratio of the width of the non-removal portion in the second direction to the distance between two adjacent fine grids.

[0036] For the TOPCon solar cell of the present invention, by thinning and removing the poly layer from a partial back region that does not contact the metal electrode, and at the same time limiting the ratio of the width of the non-removal portion (N+ region) that contacts the metal electrode to the distance between the fine grids, it can not only improve the light transmittance of the solar cell and reduce the light absorption problem caused by too thick poly layer, but also ensure that the cell has excellent electrical performance and improve the Jsc of the cell. At the same time, the passivation film layer on the back has a better passivation effect than the tunneling oxide layer + conductive passivation layer. Thinning and removing the poly layer from a partial back region can improve the Voc of the cell. However, in order to form a good PN junction, the non-removal portion cannot be too narrow, otherwise the electrical performance such as FF will be reduced. At the same time, excessive narrowing of the width of the non-removal portion will cause the fine grid region to be more prone to printing deviation, making the cell more likely to have leakage and increasing the defective rate in mass production. By limiting the width of the non-removal portion, the present invention can not only optimize the cell performance but also ensure the yield of the cell.

[0037] The present invention is provided with a plurality of removal parts and non-removal parts at intervals along a second direction, and also provided with a plurality of removal parts and non-removal parts at intervals along a first direction, and there is an intersection between the non-removal parts along the first direction and the non-removal parts along the second direction. The width of the non-removal part along the second direction referred to in the present invention refers to the width of the part that does not intersect with the non-removal part along the first direction in the second direction, that is Figure 2 the width represented by Z in Figure 2 (unit: μm); the width of the non-removal part along the first direction refers to the width of the part that does not intersect with the non-removal part along the second direction in the first direction, that is

[0038] Specifically, in some embodiments of the present invention, the distance X between two adjacent fine grids and the ratio Y (Y = Z / X) of the width of the non-removal part along the second direction to the distance between two adjacent fine grids satisfy: -0.00007X + 0.3209 < Y < -0.00041X + 1.0098.

[0039] Specifically, in some embodiments of the present invention, the distance X between two adjacent fine grids is 500 μm to 1300 μm, the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent fine grids is 14.1% to 74.7%, and the width of the non-removal part along the second direction is 130 μm to 720 μm. Preferably, the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent fine grids is 27.8% to 58.2%, and the width of the non-removal part along the second direction is 280 μm to 600 μm.

[0040] Preferably, the distance X between two adjacent fine grids is 910 μm, 1065 μm, 1150 μm.

[0041] When the distance X between two adjacent fine grids is 910 μm, the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent fine grids is 14.3% to 74.7%; the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent fine grids is 14.3%, 19.8%, 25.3%, 30.8%, 36.3%, 41.8%, 47.3%, 52.7%, 58.2%, 63.7%, 69.2%, 74.7% or the range value composed of any two of them; preferably, the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent fine grids is 30.8% to 58.2%.

[0042] When the distance X between two adjacent thin grids is 1065 μm, the ratio Y of the width of the non-removal part in the second direction to the distance between two adjacent thin grids is 14.1% - 65.7%; specifically, the ratio Y of the width of the non-removal part in the second direction to the distance between two adjacent thin grids is 14.1%, 18.8%, 23.5%, 28.2%, 32.9%, 37.6%, 42.3%, 46.9%, 51.6%, 56.3%, 61.0%, 65.7% or the range value composed of any two of them; preferably, the ratio Y of the width of the non-removal part in the second direction to the distance between two adjacent thin grids is 28.2% - 56.3%.

[0043] When the distance X between two adjacent thin grids is 1150 μm, the ratio Y of the width of the non-removal part in the second direction to the distance between two adjacent thin grids is 14.8% - 62.6%; specifically, the ratio Y of the width of the non-removal part in the second direction to the distance between two adjacent thin grids is 14.8%, 19.1%, 23.5%, 27.8%, 32.2%, 36.5%, 40.9%, 45.2%, 49.6%, 53.9%, 58.3%, 62.6% or the range value composed of any two of them; preferably, the ratio Y of the width of the non-removal part in the second direction to the distance between two adjacent thin grids is 27.8% - 49.6%.

[0044] Specifically, in some embodiments of the present invention, as Figure 2 shown, the back metal electrode further includes a plurality of main grids 11 extending in the second direction and arranged in the first direction, and the intersection positions of the thin grids 12 and the main grids 11 are connected through interconnection bars 17 in the second direction.

[0045] Specifically, in some embodiments of the present invention, the ratio of the width N of the non-removal part in the first direction to the distance M between two adjacent main grids is 1.8% - 7.8%. Preferably, the ratio of the width N of the non-removal part in the first direction to the distance M between two adjacent main grids is 3.2% - 6.7%.

[0046] Specifically, in some embodiments of the present invention, the distance M between two adjacent main grids is 7090 μm - 16800 μm, and the width N of the non-removal part in the first direction is 160 μm - 800 μm.

[0047] When the distance between two adjacent main grids is 9090 μm, the proportion of the width of the non-removal part in the first direction to the distance between two adjacent main grids is 1.8% - 8.8%; specifically, the proportion of the width of the non-removal part in the first direction to the distance between two adjacent main grids is 1.8%, 2.3%, 2.9%, 3.4%, 4.0%, 4.5%, 5.1%, 5.6%, 6.2%, 6.7%, 7.3%, 7.8% or the range value composed of any two of them; preferably, the proportion of the width of the non-removal part in the first direction to the distance between two adjacent main grids is 2.9% - 6.7%.

[0048] When the distance between two adjacent main grids is 10800 μm, the proportion of the width of the non-removal part in the first direction to the distance between two adjacent main grids is 1.9% - 7.4%; specifically, the proportion of the width of the non-removal part in the first direction to the distance between two adjacent main grids is 1.9%, 2.3%, 2.8%, 3.2%, 3.7%, 4.2%, 4.6%, 5.1%, 5.6%, 6.0%, 6.5%, 6.9%, 7.4% or the range value composed of any two of them; preferably, the proportion of the width of the non-removal part in the first direction to the distance between two adjacent main grids is 2.8% - 6.0%.

[0049] Specifically, in some embodiments of the present invention, as Figure 3-4 shown, the fine grid 12 includes a disconnected first fine grid 13 and a second fine grid 14 in the first direction, the main grids 11 are distributed at intervals in the second direction, the first fine grid 13 and the second fine grid 14 are connected through the main grid 11, and the distance c between the first fine grid 13 and the second fine grid 14 is less than the width b of the interconnection bar 17 at the contact position of the first fine grid and the second fine grid. By disconnecting the fine grid, on the premise of ensuring the transmission effect, the fine grid paste connected to the main grid is reduced, which helps to reduce costs.

[0050] The material of the main grid is different from that of the fine grid, and a material with higher solder resistance can be used to improve the reliability of the connection part with the interconnection bar. The part of the fine grid formed on the surface of the main grid can reduce the erosion of the paste on the passivation layer. Reduce the damage of the fine grid to the battery and improve Voc.

[0051] Specifically, in some embodiments of the present invention, as Figure 5 shown, the main grid 11 includes an intermediate region 15 and an end region 16, the first fine grid 13 and the second fine grid 14 are respectively connected to the two end regions 16 of the main grid 11, and the width of the intermediate region 15 in the second direction is greater than the width of the end region 16. By dividing the end part and the intermediate part of the main grid into different widths, it can not only achieve sufficient direct contact with the interconnection bar, but also reduce the consumption of the grid line paste.

[0052] Specifically, in some embodiments of the present invention, the distance between the first fine grid and the second fine grid is 0.1 mm to 2 mm.

[0053] Specifically, in some embodiments of the present invention, the length of the main grid in the first direction is 150% to 400% of the width of the interconnecting strip.

[0054] Specifically, in some embodiments of the present invention, the width of the main grid in the second direction is 120% to 700% of the width of the fine grid in the second direction.

[0055] Specifically, in some embodiments of the present invention, the conductive passivation layer is a phosphorus-doped polysilicon layer or a stacked polysilicon layer containing a silicon oxide layer doped with phosphorus; preferably, the conductive passivation layer is a phosphorus-doped polysilicon layer.

[0056] The present invention also provides a battery assembly, including the above TOPCon solar cell.

[0057] The following will further illustrate the present invention in conjunction with specific embodiments.

[0058] Embodiment 1

[0059] This embodiment provides a TOPCon solar cell, as Figure 1-2 shown, including a silicon substrate 1. On the front side of the silicon substrate 1, a boron-doped layer 2, a front passivation layer 3, and a front metal electrode 4 are provided along the direction away from the silicon substrate, and the front metal electrode 4 is in ohmic contact with the boron-doped layer 2;

[0060] On the back side of the silicon substrate 1, a plurality of removal portions 5 and non-removal portions 6 are arranged at intervals in the first direction. A back passivation layer 7 is provided on the removal portion 5, and a tunneling oxide layer 8, a doped polysilicon layer 9, a back passivation layer 7, and a back metal electrode 10 are provided on the non-removal portion 6 along the direction away from the silicon substrate 1. The back metal electrode 10 is in ohmic contact with the doped polysilicon layer 9;

[0061] The back metal electrode 10 includes a plurality of fine grids extending in the first direction and arranged in the second direction and a plurality of main grids 11 extending in the second direction and arranged in the first direction on the back passivation layer 7. The intersection positions of the fine grids and the main grids 11 are connected through an interconnecting strip 12 in the second direction;

[0062] The distance X between two adjacent thin grids is 1065 μm, the width Z of the non-removal part along the second direction is 700 μm, and the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent thin grids is 65.7%. The distance M between two adjacent main grids is 9090 μm, the width N of the non-removal part along the first direction is 410 μm, and the ratio of the width of the non-removal part along the first direction to the distance between two adjacent main grids is 4.5%.

[0063] Examples 2-24, Comparative Examples 1-6.

[0064] The differences between Examples 2-24, Comparative Examples 1-6 and Example 1 are only that the distance X between two adjacent thin grids and the ratio Y of the width of the non-removal part along the second direction to the distance between two adjacent thin grids are specifically shown in Table 1. The rest is the same as that of Example 1, and the test results are shown in Table 1.

[0065] Group Fine grid pitch X / μm Width of non-removal part Z / μm Y Voc (mV) <![CDATA[Jsc (mA / cm 2 )]]> FF (%) Eta (%) Example 1 1065 700 65.7% 729.279 41.834 84.216 25.693 Example 2 1065 650 61.0% 729.461 41.875 84.131 25.699 Example 3 1065 600 56.3% 729.644 41.917 84.047 25.706 Example 4 1065 550 51.6% 729.826 41.959 83.963 25.712 Example 5 1065 500 46.9% 730.009 42.001 83.879 25.718 Example 6 1065 450 42.3% 730.191 42.043 83.795 25.725 Example 7 1065 400 37.6% 730.374 42.085 83.703 25.729 Example 8 1065 350 32.9% 730.556 42.127 83.603 25.730 Example 9 1065 300 28.2% 730.739 42.148 83.503 25.718 Example 10 1065 250 23.5% 730.723 42.153 83.436 25.700 Example 11 1065 200 18.8% 730.656 42.131 83.427 25.682 Example 12 1065 150 14.1% 730.521 42.089 83.419 25.649 Example 13 1150 720 62.6% 729.264 41.521 84.024 25.443 Example 14 1150 670 58.3% 729.441 41.571 83.949 25.456 Example 15 1150 620 53.9% 729.616 41.621 83.877 25.471 Example 16 1150 570 49.6% 729.793 41.671 83.802 25.485 Example 17 1150 520 45.2% 729.969 41.721 83.731 25.500 Example 18 1150 470 40.9% 730.144 41.771 83.639 25.509 Example 19 1150 420 36.5% 730.320 41.821 83.547 25.517 Example 20 1150 370 32.2% 730.496 41.871 83.421 25.516 Example 21 1150 320 27.8% 730.672 41.892 83.304 25.499 Example 22 1150 270 23.5% 730.849 41.888 83.221 25.477 Example 23 1150 220 19.1% 731.025 41.884 83.055 25.430 Example 24 1150 170 14.8% 731.201 41.880 82.889 25.382 Comparative Example 1 1065 800 75.1% 728.900 41.750 84.300 25.654 Comparative Example 2 1065 750 70.4% 729.097 41.792 84.300 25.686 Comparative Example 3 1065 100 9.4% 730.210 42.005 75.077 23.028 Comparative Example 4 1150 820 71.3% 728.900 41.430 84.100 25.397 Comparative Example 5 1150 770 67.0% 729.090 41.471 84.100 25.429 Comparative Example 6 1150 120 10.4% 731.378 41.796 74.600 22.804

[0066] It can be seen from the test results in Table 1 that for the TOPCon solar cell of the present invention, by thinning and removing the area of the back of the battery silicon substrate that does not contact the metal electrode, and controlling the fine grid spacing and the width of the non-removal part along the second direction to regulate the removal range, it can not only improve the light transmittance of the solar cell and reduce the light absorption problem caused by too thick poly layer, but also ensure that the battery has excellent electrical performance.

[0067] Examples 25-48, Comparative Examples 7-11.

[0068] The differences between Examples 25-48, Comparative Examples 7-11 and Example 6 are only that the distance M between two adjacent main grids and the ratio N / M of the width of the non-removal part along the first direction to the distance between two adjacent main grids are specifically shown in Table 2. The rest is the same as that of Example 6, and the test results are shown in Table 2.

[0069] Group Main grid pitch M / μm Width of non-removal part N / μm P Voc (mV) <![CDATA[Jsc (mA / cm 2 )]]> FF (%) Eta (%) Example 25 10800 800 7.4% 728.520 41.450 83.621 25.251 Example 26 10800 750 6.9% 728.607 41.450 83.621 25.254 Example 27 10800 700 6.5% 728.695 41.450 83.617 25.256 Example 28 10800 650 6.0% 728.782 41.450 83.615 25.259 Example 29 10800 600 5.6% 728.870 41.450 83.613 25.261 Example 30 10800 550 5.1% 728.957 41.451 83.612 25.264 Example 31 10800 500 4.6% 729.030 41.451 83.610 25.266 Example 32 10800 450 4.2% 729.103 41.451 83.608 25.268 Example 33 10800 400 3.7% 729.176 41.451 83.599 25.268 Example 34 10800 350 3.2% 729.249 41.451 83.582 25.265 Example 35 10800 300 2.8% 729.322 41.451 83.545 25.256 Example 36 10800 250 2.3% 729.395 41.446 83.532 25.252 Example 37 10800 200 1.9% 729.468 41.442 83.520 25.249 Example 38 9090 710 7.8% 729.534 42.043 83.846 25.717 Example 39 9090 660 7.3% 729.644 42.043 83.837 25.718 Example 40 9090 610 6.7% 729.753 42.043 83.829 25.719 Example 41 9090 560 6.2% 729.863 42.043 83.820 25.721 Example 42 9090 510 5.6% 729.972 42.043 83.812 25.722 Example 43 9090 460 5.1% 730.082 42.043 83.804 25.724 Example 44 9090 360 4.0% 730.301 42.044 83.787 25.726 Example 45 9090 310 3.4% 730.410 42.044 83.770 25.725 Example 46 9090 260 2.9% 730.520 42.044 83.737 25.719 Example 47 9090 210 2.3% 730.629 42.039 83.713 25.713 Example 48 9090 160 1.8% 730.739 42.035 83.688 25.706 Comparative Example 7 10800 150 1.4% 729.030 41.069 82.936 24.832 Comparative Example 8 10800 100 0.9% 728.374 40.741 82.355 24.438 Comparative Example 9 9090 760 8.4% 729.425 42.043 83.846 25.713 Comparative Example 10 9090 110 1.2% 730.301 41.657 83.102 25.281 Comparative Example 11 9090 60 0.7% 729.643 41.324 82.520 24.881

[0070] It can be seen from the test results in Table 2 that when the fine grid spacing and the width of the non-removal part are controlled within a certain range, by further regulating the relationship between the main grid spacing and the width of the non-removal part in the main grid direction, the obtained solar cells all have good electrical performance.

[0071] The above further describes the present invention with the help of specific examples. However, it should be understood that this specific description should not be construed as a limitation on the essence and scope of the present invention. Various modifications made by those of ordinary skill in the art to the above examples after reading this specification all fall within the scope protected by the present invention.

Claims

1. A TOPCon solar cell, comprising a silicon substrate, a boron-doped layer, a front passivation layer, and a front metal electrode are disposed on the front of the silicon substrate in a direction away from the silicon substrate, and the front metal electrode is in ohmic contact with the boron-doped layer; characterized in that: On the back of the silicon substrate, a plurality of removal parts and non-removal parts are arranged at intervals in a second direction, a back passivation layer is provided on the removal part, and a tunneling oxide layer, a conductive passivation layer, a back passivation layer, and a back metal electrode are disposed on the non-removal part in a direction away from the silicon substrate, and the back metal electrode is in ohmic contact with the conductive passivation layer; The back metal electrode includes a plurality of fine grids extending in a first direction and arranged in a second direction on the back passivation layer; The TOPCon solar cell satisfies: -0.00002X + 0.1240 < Y < -0.00050X + 1.2067; wherein, X is the distance between two adjacent fine grids, and the unit is μm; Y is the ratio of the width of the non-removal part in the second direction to the distance between two adjacent fine grids.

2. The TOPCon solar cell according to claim 1, characterized in that, The distance X between two adjacent fine grids and the ratio Y of the width of the non-removal part in the second direction to the distance between two adjacent fine grids satisfy: -0.00007X + 0.3209 < Y < -0.00041X + 1.0098.

3. The TOPCon solar cell according to claim 1, characterized in that, The distance X between two adjacent fine grids is 500 μm to 1300 μm, the ratio Y of the width of the non-removal part in the second direction to the distance between two adjacent fine grids is 14.1% to 74.7%, and the width Z of the non-removal part in the second direction is 130 μm to 720 μm.

4. The TOPCon solar cell according to claim 3, characterized in that, The ratio Y of the width of the non-removal part in the second direction to the distance between two adjacent fine grids is 27.8% to 58.2%, and the width Z of the non-removal part in the second direction is 280 μm to 600 μm.

5. The TOPCon solar cell according to claim 1, characterized in that, The conductive passivation layer is a phosphorus-doped polysilicon layer.

6. The TOPCon solar cell according to claim 1, wherein, The conductive passivation layer is a phosphorus-doped stacked polysilicon layer containing a silicon oxide layer.

7. A battery assembly, characterized in that, Including the TOPCon solar cell according to any one of claims 1-6.

8. The battery assembly according to claim 7, wherein, The back metal electrode further includes a plurality of main grids extending in the second direction and arranged in the first direction, and the intersection positions of the fine grids and the main grids are connected through interconnection bars in the second direction.

9. The battery assembly according to claim 8, characterized in that, The fine grid includes a disconnected first fine grid and a second fine grid in the first direction, the main grids are distributed at intervals in the second direction, the first fine grid and the second fine grid are connected through the main grid, and the distance between the first fine grid and the second fine grid is less than the width of the interconnection bar at the contact positions of the first fine grid and the second fine grid.

10. The battery assembly according to claim 9, wherein, The main grid includes an intermediate region and end regions, the first fine grid and the second fine grid are respectively connected to the two end regions of the main grid, and the width of the intermediate region in the second direction is greater than the width of the end regions.

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