Solar cell, battery module and photovoltaic system

Abstract

This application relates to the field of photovoltaics, and in particular to a solar cell, a battery module, and a photovoltaic system. A doping layer and a passivation layer are sequentially stacked on the back surface of the solar cell in a direction away from the back surface; and / or, a doping layer and a passivation layer are sequentially stacked on the front surface of the solar cell in a direction away from the front surface; the passivation layer is provided with light spots in the thickness direction thereof, and the fine grid is disposed on a side of the passivation layer away from the doping layer and is electrically connected to the doping layer through the light spots; the fine grid covers a part of the light spots; the number of the light spots covered by the fine grid is more than the number of the light spots not covered by the fine grid. In this way, it can be ensured that there are a sufficient number of light spots electrically connected to the fine grid, and the photoelectric conversion effect of the solar cell can be ensured.

Description

Technical Field

[0001] This application relates to the field of photovoltaics, and in particular, to a solar cell, a battery module, and a photovoltaic system. Background Art

[0002] A solar cell is a device that converts sunlight into electrical energy through the photovoltaic effect and is a clean and renewable energy technology. Solar cells include single-sided cells and double-sided cells. Among them, a single-sided cell means that the positive and negative electrodes of the cell are both arranged on the back of the cell, so that the front surface is completely free from the occlusion of metal grid lines. A double-sided cell means that the positive and negative electrodes of the cell are respectively arranged on the front and back of the cell.

[0003] A doping layer and a passivation layer are sequentially provided on the surface of the cell. Laser is used to form laser spots by opening holes in the passivation layer, and then a fine grid is coated on the passivation layer. The fine grid passes through the spots, so that the fine grid realizes electrical connection with the doping layer through the spots. In the related art, the distribution relationship between the spots and the fine grid affects the photoelectric conversion effect of the solar cell. Summary of the Invention

[0004] This application provides a solar cell, a battery module, and a photovoltaic system to optimize the photoelectric conversion effect.

[0005] In a first aspect, this application provides a solar cell. A doping layer and a passivation layer are sequentially stacked on the back of the solar cell in a direction away from the back; and / or, a doping layer and a passivation layer are sequentially stacked on the front of the solar cell in a direction away from the front;

[0006] The passivation layer is provided with spots in its thickness direction. The fine grid is arranged on the side of the passivation layer away from the doping layer and is electrically connected to the doping layer through the spots; the fine grid covers part of the spots; the number of the spots covered by the fine grid is more than the number of the spots not covered by the fine grid.

[0007] Further, a plurality of the spots are arranged at intervals along the length extension direction of the fine grid.

[0008] Further, the spots are circular or square or irregular in shape.

[0009] Further, the size range of the spots in the width direction of the fine grid is 10 micrometers to 50 micrometers.

[0010] Further, the back of the solar cell includes first doping regions and second doping regions that are alternately arranged in sequence; or, the front and back of the solar cell are respectively provided with a first doping region and a second doping region;

[0011] The first doped region is provided with a first fine grid and a plurality of first light spots; the first fine grid covers part of the first light spots; the number of the first light spots covered by the first fine grid is more than the number of the first light spots not covered by the first fine grid;

[0012] The second doped region is provided with a second fine grid and a plurality of second light spots; the second fine grid covers part of the first light spots; the number of the second light spots covered by the second fine grid is more than the number of the second light spots not covered by the second fine grid.

[0013] Wherein, the polarity of the first fine grid is opposite to the polarity of the second fine grid.

[0014] Further, the number of the first light spots not covered by the first fine grid in the first doped region is more than the number of the second light spots not covered by the second fine grid in the second doped region.

[0015] Further, the distribution density of the first light spots in the first region is greater than the distribution density of the second light spots in the second region.

[0016] Further, the center distance between two adjacent first light spots is less than the center distance between two adjacent second light spots.

[0017] Further, the center distance range between two adjacent first light spots is 40 micrometers to 120 micrometers.

[0018] Further, the center distance range between two adjacent second light spots is 80 micrometers to 160 micrometers.

[0019] Further, the fine grid includes a narrow portion and a wide portion, the narrow portion and the wide portion are alternately arranged along the length direction of the fine grid and are connected in sequence; the maximum width of the wide portion is greater than the maximum width of the narrow portion; the wide portion correspondingly covers the light spot.

[0020] Further, define the projection of the edge extending along the length direction of the fine grid on the front or back surface of the solar cell as an edge line, the edge line has inflection points, and the inflection points include peak points and valley points;

[0021] The peak point is located in the wide portion, and the peak point is located on the edge line at the maximum width position of the wide portion;

[0022] The valley point is located in the narrow portion, and the valley point is located on the edge line at the minimum width position of the narrow portion.

[0023] Further, when the edge line has a plurality of the peak points and a plurality of the valley points, the peak points and the valley points are arranged alternately and at intervals along the length extension direction of the edge line.

[0024] Further, the transition from the peak point to the valley point is a smooth transition, an arc transition or a step mutation.

[0025] Further, the inflection point is an arc, a straight line or a broken line.

[0026] Further, when the inflection point is an arc, the included angle range formed by the intersection of the tangents of the parts of the edge line on both sides of the inflection point is 30° to 150°;

[0027] When the inflection point is a broken line, the included angle range formed by the parts of the edge line on both sides of the inflection point is 30° to 150°;

[0028] When the inflection point is a straight line, the transition from the peak point to the valley point is a step mutation.

[0029] Further, the two edge lines extending along the length direction of the fine grid are symmetrically arranged.

[0030] Further, the inflection points of the two edge lines extending along the length direction of the fine grid are arranged in a staggered manner.

[0031] Further, the spacing range between the two edge lines extending along the length direction of the fine grid is 10 microns to 250 microns.

[0032] Further, the maximum width of the narrow part is less than or equal to the size of the light spot along the width direction of the fine grid.

[0033] Further, the maximum width of the wide part is greater than the size of the light spot along the width direction of the fine grid.

[0034] Further, the minimum width of the wide part is greater than or equal to the size of the light spot along the width direction of the fine grid.

[0035] Further, the width of the fine grid is less than the size of the light spot along the width direction of the fine grid, and a part of the projection of the fine grid on the surface of the solar cell overlaps with the projection of the light spot on the surface of the solar cell.

[0036] Further, the middle area of the projection of the light spot on the front or the back overlaps with the projection of the fine grid on the front or the back.

[0037] Further, the width range of the fine grid is 10 microns to 250 microns.

[0038] Further, the fine grid includes at least two fine grid portions, and a plurality of the fine grid portions are spaced apart along the width direction of the fine grid. The projection of each fine grid portion on the front or the back partially overlaps with the projection of the light spot on the front or the back.

[0039] Further, the number of the fine grid portions is two, and the two fine grid portions respectively cover two ends of the light spot along the width direction of the fine grid.

[0040] Further, the size of the light spot along the width direction of the fine grid is greater than the distance C between the two fine grid portions.

[0041] Further, the width range of the fine grid portion is from 10 microns to 100 microns.

[0042] Further, the sum of the widths of the two fine grid portions of the fine grid is less than 200 microns.

[0043] In a second aspect, the present application provides a battery assembly, including the solar cell as described above.

[0044] In a third aspect, the present application provides a photovoltaic system, including the battery assembly as described above.

[0045] The above technical solutions provided by the present application have the following advantages compared with the prior art:

[0046] In the technical solution of the present application, the number of light spots covered by the fine grid on the surface of the solar cell is more than the number of light spots not covered by the fine grid. In this way, it can be ensured that there are a sufficient number of light spots electrically connected to the fine grid, and the photoelectric conversion effect of the solar cell can be ensured. Description of the Drawings

[0047] The drawings here are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0049] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated, and the drawings in the drawings do not constitute a proportional limitation.

[0050] Figure 1Schematic diagram of the back surface of the solar cell in the first embodiment of the present application;

[0051] Figure 2 Schematic diagram of the back surface of the solar cell in the second embodiment of the present application;

[0052] Figure 3 Schematic diagram of the back surface of the solar cell in the third embodiment of the present application;

[0053] Figure 4 Schematic diagram of a partial view of the first fine grid with a stepped mutation of the first edge line in an embodiment of the present application;

[0054] Figure 5 Schematic diagram of a partial view of the first fine grid with a stepped mutation of the first edge line in another embodiment of the present application;

[0055] Figure 6 Schematic diagram of a partial view of the first fine grid with a pointed serrated first edge line in an embodiment of the present application;

[0056] Figure 7 Schematic diagram of a partial view of the first fine grid with a round - headed serrated first edge line in an embodiment of the present application;

[0057] Figure 8 Schematic diagram of the back surface of the solar cell in the fourth embodiment of the present application;

[0058] Figure 9a Schematic diagram of the back surface of the solar cell in the fifth embodiment of the present application;

[0059] Figure 9b Schematic diagram of the back surface of the solar cell in the sixth embodiment of the present application;

[0060] Figure 10 Schematic diagram of the first light spot distribution in the first doping region;

[0061] Figure 11 Schematic diagram of the second light spot distribution in the second doping region;

[0062] Figure 12 Schematic cross - sectional view of a back - contact solar cell.

[0063] Explanation of reference numerals:

[0064] Fine grid 1, first fine grid 1a, first narrow part 11a, first wide part 12a, second fine grid 1b, second narrow part 11b, second wide part 12b, first edge line La, second edge line Lb, peak point M, valley point N, light spot 2, first light spot 2a, second light spot 2b, fine grid part 13, first doping region 100, first doping layer 110, second doping region 200, second doping layer 210, substrate 300, first passivation layer 410, second passivation layer 420, first tunneling layer 510, second tunneling layer 520. Detailed implementation mode

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0066] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application. In addition, the present application may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0067] For ease of description, spatially relative relationship terms may be used in the text to describe the relative positional relationship or movement of one element or feature shown in the figure relative to another element or feature. These relative relationship terms such as "inside", "outside", "inner side", "outer side", "below", "beneath", "above", "over", "front", "rear", etc. This spatially relative relationship term is intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or attitude change or movement state change, then these directional indications will also change accordingly. For example, an element described as "below other elements or features" or "beneath other elements or features" will subsequently be oriented as "above other elements or features" or "over other elements or features". Therefore, the example term "below" can include both above and below orientations. The device may be oriented otherwise (rotated 90 degrees or in other directions) and the spatially relative relationship descriptors used in the text are interpreted accordingly.

[0068] In the first aspect, Figures 1 to 5A solar cell provided by an embodiment of the present application, the solar cell includes a substrate 300, and the substrate 300 has opposite back and front surfaces.

[0069] A solar cell provided by the present application may be a single-sided cell. Specifically, referring to Figure 12 , the solar cell includes a substrate 300, and the substrate 300 has opposite back and front surfaces. The back surface is provided with a plurality of first doping regions 100 and second doping regions 200 arranged alternately. The first doping region 100 is provided with a first doping layer 110, and the second doping region 200 is provided with a second doping layer 210. The type of doping element in the first doping layer 110 is different from the type of doping element in the second doping layer 210. The front surface is located on the front surface of the solar cell and serves as a light-receiving surface for receiving incident sunlight.

[0070] Exemplarily, an IBC cell (Interdigitated Back Contact cell) is a single-sided cell. An IBC cell refers to a back-junction back-contact solar cell structure in which positive and negative metal electrodes are arranged in an interdigitated manner on the backlight surface of the cell. Among them, the back-junction means that the PN junction is located on the back surface of the cell. Since the PN junction and the metal electrodes of the IBC cell are both located on the back surface of the cell and there is no metal electrode shading on the front surface, a very high short-circuit current and conversion efficiency can be obtained.

[0071] Referring to Figure 12 , a first tunneling layer 510 is further provided between the first doping layer 110 and the substrate 300, and a second tunneling layer 520 is further provided between the second doping layer 210 and the substrate 300. The first tunneling layer 510 and the second tunneling layer 520 may be silicon oxide layers. By utilizing the tunneling passivation effect of the first tunneling layer 510 and the second tunneling layer 520, the cell efficiency of the solar cell can be further improved.

[0072] In some other embodiments, the solar cell provided by the present application may also be a double-sided cell. Specifically, the solar cell includes a substrate 300, and the substrate 300 has opposite back and front surfaces. The first doping region 100 and the second doping region 200 are respectively provided on the front and back surfaces of the substrate 300. The first doping region 100 is provided with a first doping layer 110, and the second doping region 200 is provided with a second doping layer 210. The type of doping element in the first doping layer 110 is different from the type of doping element in the second doping layer 210. The front surface is located on the front surface of the solar cell and serves as a light-receiving surface for receiving incident sunlight.

[0073] In the present application, the IBC cell is taken as an example for illustration.

[0074] The substrate 300 is used to receive incident light and generate photogenerated carriers. In some embodiments, the substrate 300 may be a semiconductor substrate 300, such as silicon, germanium, germanium silicon, or silicon on insulator.

[0075] The substrate 300 may be an N-type semiconductor substrate 300 or a P-type semiconductor substrate 300. The N-type semiconductor substrate 300 is doped with an N-type doping element, which may be any one of phosphorus, bismuth, antimony, or arsenic. The P-type semiconductor substrate 300 is doped with a P-type element, which may be any one of boron, aluminum, gallium, or indium.

[0076] In the embodiment of the present application, a second doping region 200 may be arranged between any two adjacent first doping regions 100 , and a first doping region 100 may be arranged between any two adjacent second doping regions 200 , that is, the first doping regions 100 and the second doping regions 200 are alternately arranged.

[0077] The first doping layer 110 may be doped with an N-type doping element or a P-type doping element, and the second doping layer 210 may be doped with a P-type doping element or an N-type doping element. The type of doping element doped in one of the first doping layer 110 and the second doping layer 210 is the same as the type of doping element doped in the substrate 300. For example, if the substrate 300 is an N-type substrate 300, the first doping layer 110 may be doped with an N-type doping element, and the second doping layer 210 may be doped with a P-type doping element, then a PN junction is formed between the second doping layer 210 and the substrate 300, effectively shunting carriers.

[0078] In an embodiment of the present application, the solar cell further includes a passivation layer located on the back side, the passivation layer may be a single layer structure or a stacked layer structure, and the material of the passivation layer may be one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbonitride, titanium oxide, hafnium oxide or aluminum oxide. It should be noted that in some embodiments, the solar cell further includes a passivation layer located on the front side.

[0079] In the embodiment of the present application, the passivation layer located on the side of the first doping layer 110 away from the substrate 300 is defined as the first passivation layer 410, and the passivation layer located on the side of the second doping layer 210 away from the substrate 300 is defined as the second passivation layer 420. The first light spot 2a and the second light spot 2b can be formed by opening holes in the first passivation layer 410 and the second passivation layer 420 by laser, wherein the first light spot 2a penetrates the first passivation layer 410, and the second light spot 2b penetrates the second passivation layer 420.

[0080] The first fine grid 1a is formed on the first passivation layer 410 by printing or coating, so that the first fine grid 1a is connected to the first doping layer 110 through the first light spot 2a. Specifically, the first fine grid 1a includes a first part on the side of the first passivation layer 410 facing away from the first doping layer 110 and a second part passing through the first light spot 2a. The first part is electrically connected to the first doping layer 110 through the second part, achieving the effect that the first fine grid 1a collects and aggregates the current of the solar cell.

[0081] Similarly, the second fine grid 1b is formed on the second passivation layer 420 by printing or coating, so that the second fine grid 1b is connected to the second doping layer 210 through the second light spot 2b. Specifically, the second fine grid 1b includes a first part on the side of the second passivation layer 420 facing away from the second doping layer 210 and a second part penetrating through the second light spot 2b. The first part is electrically connected to the second doping layer 210 through the second part, achieving the effect that the second fine grid 1b collects and aggregates the current of the solar cell.

[0082] Among them, the materials of the first fine grid 1a and the second fine grid 1b can be one or more of tin, aluminum, silver, gold, nickel, molybdenum or copper.

[0083] The width pair of the fine grid 1 on the back will affect the secondary reflection of sunlight on the back and the photoelectric conversion efficiency. The width pair of the fine grid 1 on the front will block the entry of sunlight on the front and affect the photoelectric conversion efficiency. To solve this technical problem, the present application has made a first design scheme for the structure of the fine grid 1: the surface of the solar cell is provided with a fine grid 1, and the fine grid 1 includes a narrow part 11 and a wide part 12, and the narrow part 11 and the wide part 12 are alternately arranged along the length direction of the fine grid 1 and are connected in sequence; the maximum width of the wide part 12 is greater than the maximum width of the narrow part 11.

[0084] It should be noted that in some embodiments, the structure of the first fine grid 1a adopts the first design scheme for the structure of the fine grid 1; in some other embodiments, the structure of the second fine grid 1b adopts the first design scheme for the structure of the fine grid 1; in still some other embodiments, the structures of both the first fine grid 1a and the second fine grid 1b adopt the first design scheme for the structure of the fine grid 1.

[0085] It should also be noted that when the solar cell is a bifacial cell, the front and back of the solar cell are respectively provided with a first fine grid 1a and a second fine grid 1b, and the structure of the first fine grid 1a and the structure of the second fine grid 1b can be the same or different, and the sizes of the first fine grid 1a on the front and the second fine grid 1b on the back can be different or the same.

[0086] Reference Figures 1 to 3, in the technical solution of this embodiment, the first doping region 100 is a P region, and the second doping region 200 is an N region.

[0087] In some embodiments, the first narrow grid 1a located in the first doping region 100 includes a first narrow portion 11a and a first wide portion 12a. The first narrow portion 11a and the first wide portion 12a are alternately arranged along the length direction of the first narrow grid 1a and are connected in sequence; the maximum width of the first wide portion 12a is greater than the maximum width of the first narrow portion 11a.

[0088] In the technical solution of this application, the first narrow grid 1a arranged on the back surface of the solar cell includes a first narrow portion 11a and a first wide portion 12a. The first wide portion 12a can be used to correspond to the first light spot 2a to improve the ability to collect current, and the width of the first narrow portion 11a is less than the width of the first wide portion 12a, reducing the area occupied on the back surface of the solar cell. That is, the solution of this application ensures that the first narrow grid 1a can be electrically connected to the first doping layer 110 through the first light spot 2a while overall reducing the area occupied by the first narrow grid 1 on the back surface of the solar cell, reducing the light shielding and reflection of the first narrow grid 1a, and improving the photoelectric conversion efficiency.

[0089] Among them, the maximum width of the first wide portion 12a in this application is greater than the maximum width of the first narrow portion 11a, reducing the resistance of the first narrow grid, which is beneficial to improving the carrier transmission ability of the first narrow grid, the fill factor of the battery, and the conversion efficiency.

[0090] In some embodiments, the second narrow grid 1b located in the second doping region 200 includes a second narrow portion 11b and a second wide portion 12b. The second narrow portion 11b and the second wide portion 12b are alternately arranged along the length direction of the second narrow grid 1b and are connected in sequence; the maximum width of the second wide portion 12b is greater than the maximum width of the second narrow portion 11b.

[0091] In the technical solution of this application, the second narrow grid 1b arranged on the back surface of the solar cell includes a second narrow portion 11b and a second wide portion 12b. The second wide portion 12b can be used to correspond to the second light spot 2b to improve the ability to collect current, and the width of the second narrow portion 11b is less than the width of the second wide portion 12b, reducing the area occupied on the back surface of the solar cell. That is, the solution of this application ensures that the second narrow grid 1b can be electrically connected to the second doping layer 210 through the second light spot 2b while overall reducing the area occupied by the second narrow grid 1 on the back surface of the solar cell, reducing the light shielding and reflection of the second narrow grid 1b, and improving the photoelectric conversion efficiency.

[0092] Furthermore, in the present application, the maximum width of the second wide portion 12b is greater than the maximum width of the second narrow portion 11b, reducing the resistance of the second fine grid, which is beneficial to improving the carrier transport ability of the second fine grid, the cell fill factor, and the conversion efficiency.

[0093] Reference Figure 1 and Figure 4 Define the projection of the edge of the first fine grid 1a extending along its length direction on the back surface of the solar cell as the first edge line. The first edge line has inflection points, and the inflection points include a peak point M and a valley point N. The peak point M is located in the first wide portion 12a, and the peak point M corresponds to the position of the maximum width of the first wide portion 12a. The valley point N is located in the first narrow portion 11a, and the valley point N corresponds to the position of the minimum width of the first narrow portion 11a.

[0094] There is a valley point N between two adjacent peak points M, and there is a peak point M between two adjacent valley points N, so that the peak point M and the valley point N are alternately arranged.

[0095] The peak point M corresponds to the position of the maximum width of the first wide portion 12a, that is, the width of the first fine grid 1a corresponding to the peak point M is larger. The first light spot 2a is located in the first wide portion 12a, reducing the resistance of the first fine grid, which is beneficial to improving the carrier transport ability of the first fine grid, the cell fill factor, and the conversion efficiency. The valley point N corresponds to the minimum width of the first narrow portion 11a, which serves the purpose of reducing the area occupied on the back surface of the solar cell and does not affect the effect of the first fine grid 1a being electrically connected to the first doping layer 110 through the first light spot 2a.

[0096] Reference Figure 1 Define the projection of the edge of the second fine grid 1b extending along its length direction on the back surface of the solar cell as the second edge line. The second edge line has inflection points, and the inflection points include a peak point M and a valley point N. The peak point M is located in the second wide portion 12b, and the peak point M corresponds to the position of the maximum width of the second wide portion 12b. The valley point N is located in the first narrow portion 11a, and the valley point N corresponds to the position of the minimum width of the second narrow portion 11b.

[0097] There is a valley point N between two adjacent peak points M, and there is a peak point M between two adjacent valley points N, so that the peak point M and the valley point N are alternately arranged.

[0098] The peak point M corresponds to the position of the maximum width of the second wide portion 12b, that is, the width of the second fine grid 1b corresponding to the peak point M is relatively large. The second light spot 2b is located in the second wide portion 12b, reducing the resistance of the second fine grid, which is beneficial to improving the carrier transport ability of the second fine grid, the fill factor and the conversion efficiency of the battery. The trough point N corresponds to the minimum width of the second narrow portion 11b, which serves the purpose of reducing the area occupied on the back surface of the solar cell, and does not affect the effect of electrically connecting the second fine grid 1b to the second doping layer 210 through the second light spot 2b.

[0099] In some embodiments, referring to Figure 3 and Figure 6 , the first edge line is overall in a pointed serrated shape, and is bent in a broken line at the peak point M and also bent in a broken line at the trough point N. There is a smooth transition from the peak point M to the trough point N. The included angle A formed by the portions of the edge line on both sides of the inflection point (peak point M or trough point N) ranges from 30° to 150°; optionally, the included angle A is 30°, 35°, 45°, 60°, 90°, 120°, 130°, 140° or 150°. The second edge line may be the same as or different from the first edge line in shape.

[0100] In some embodiments, referring to Figure 7 , the first edge line is overall in a round-headed serrated shape, and is bent in an arc at the peak point M and also bent in an arc at the trough point N. There is a smooth transition from the peak point M to the trough point N. The included angle B formed by the intersection of the tangents of the edge line on both sides of the inflection point (peak point M or trough point N) ranges from 30° to 150°; optionally, the included angle B is 30°, 35°, 45°, 60°, 90°, 120°, 130°, 140° or 150°. The second edge line may be the same as or different from the first edge line in shape.

[0101] In some embodiments, referring to Figure 1 , Figure 2 , Figure 4 and Figure 5, The first edge line and the second edge line are overall in the shape of flat-topped sawteeth, such that the first narrow part 11a and the second narrow part 11b are overall square-shaped, and the first wide part 12a and the second wide part 12b are overall square-shaped. In this embodiment, the part of the first edge line corresponding to the first wide part 12a and the first narrow part 11a is straight, the second edge line corresponding to the second wide part 12b and the second narrow part 11b is straight, and there are step mutations at the junctions of the first wide part 12a and the first narrow part 11a, and at the junctions of the second wide part 12b and the second narrow part 11b; wherein the position of the first narrow part 11a corresponding to the junction of the first wide part 12a and the first narrow part 11a is the trough point N, and the position of the first wide part 12a corresponding to the junction of the first wide part 12a and the first narrow part 11a is the peak point M; the position of the second narrow part 11b corresponding to the junction of the second wide part 12b and the second narrow part 11b is the trough point N, and the position of the second wide part 12b corresponding to the junction of the second wide part 12b and the second narrow part 11b is the peak point M.

[0102] Wherein, Figure 1 , Figure 2 and Figure 4 are shown as having step mutations along the width direction of the fine grid 1. Figure 5 is shown as another form of step mutation, Figure 5 with a step mutation along a direction at an angle to the length direction of the fine grid 1.

[0103] In some embodiments, the first edge line and / or the second edge line can also be some other irregular shapes, as long as the shape including the peak point M and the trough point N is satisfied.

[0104] Referring to Figure 1 and Figure 3 , in some embodiments, the two first edge lines along the length direction of each first fine grid 1a are symmetrically arranged. That is, the peak point M of one first edge line is arranged corresponding to the peak point M of the other first edge line, and the trough point N of one first edge line is arranged corresponding to the trough point N of the other first edge line.

[0105] The two second edge lines along the length direction of each second fine grid 1b are symmetrically arranged. That is, the peak point M of one second edge line is arranged corresponding to the peak point M of the other second edge line, and the trough point N of one second edge line is arranged corresponding to the trough point N of the other second edge line.

[0106] Referring to Figure 2 , in some embodiments, the inflection point distributions of the two first edge lines along the length direction of each first fine grid 1a are arranged in a staggered manner. That is, the peak point M of one first edge line is arranged corresponding to the trough point N of the other first edge line. The trough point N of one first edge line is arranged corresponding to the peak point M of the other first edge line.

[0107] The inflection points of the two second edge lines of each second fine grid 1b along its length direction are arranged in a staggered manner. That is, the peak point M of one second edge line corresponds to the valley point N of the other second edge line. The valley point N of one second edge line corresponds to the peak point M of the other second edge line.

[0108] In the technical solution of this embodiment, the distance range between the two first edge lines of each first fine grid 1a along its length direction is 10 micrometers to 250 micrometers. It can be understood that the minimum width of the first narrow part 11a, that is, the width of the first fine grid 1 corresponding to the valley point N, is 10 micrometers, and the maximum width of the first wide part 12a, that is, the width of the first fine grid 1 corresponding to the peak point M, is 250 micrometers. In this way, the overlapping area of the first fine grid 1a and the projection of the first light spot 2a can be ensured, that is, it can be ensured that the cross-sectional area of the second part of the first fine grid 1a located within the first light spot 2a is not too small, and the current collection ability of the first fine grid 1a can be guaranteed.

[0109] In the technical solution of this embodiment, the size range H1 of the first light spot 2a along the width direction of the first fine grid 1 is 10 micrometers to 50 micrometers. In this way, the size of the first light spot 2a is designed within a suitable range, avoiding the situation that the size of the first light spot 2a is too large and affecting the structural performance of the passivation layer, and also avoiding the situation that the size of the first light spot 2a is too small and affecting the current collection ability of the first fine grid 1a.

[0110] In the technical solution of this embodiment, the distance range between the two second edge lines of each second fine grid 1b along its length direction is 10 micrometers to 250 micrometers. It can be understood that the minimum width of the second narrow part 11b, that is, the width of the second fine grid 1 corresponding to the valley point N, is 10 micrometers, and the maximum width of the second wide part 12b, that is, the width of the second fine grid 1 corresponding to the peak point M, is 250 micrometers. In this way, the overlapping area of the second fine grid 1b and the second light spot 2b can be ensured, that is, it can be ensured that the cross-sectional area of the second part of the second fine grid 1b located within the second light spot 2b is not too small, and the current collection ability of the second fine grid 1b can be guaranteed.

[0111] In the technical solution of this embodiment, the size range H2 of the second light spot 2b along the width direction of the second fine grid 1 is 10 micrometers to 50 micrometers. In this way, the size of the second light spot 2b is designed within a suitable range, avoiding the situation that the size of the second light spot 2b is too large and affecting the structural performance of the passivation layer, and also avoiding the situation that the size of the second light spot 2b is too small and affecting the current collection ability of the second fine grid 1b.

[0112] In the technical solution of this embodiment, referring to Figures 1 to 3, each first fine grid 1a includes a plurality of first wide portions 12a and a plurality of first narrow portions 11a, and the first wide portions 12a and the first narrow portions 11a are alternately arranged. Each second fine grid 1b includes a plurality of second wide portions 12b and a plurality of second narrow portions 11b, and the second wide portions 12b and the second narrow portions 11b are alternately arranged.

[0113] The number of the second light spots 2b is a plurality, and the plurality of second light spots 2b are arranged at intervals; the second light spots 2b are arranged corresponding to the second wide portions 12b, and each second wide portion 12b covers part or all of one second light spot 2b.

[0114] In some embodiments, each first wide portion 12a corresponds to one first light spot 2a. Each second wide portion 12b corresponds to one second light spot 2b.

[0115] In other embodiments, each first wide portion 12a corresponds to at least two first light spots 2a, and the plurality of first light spots 2a corresponding to each first wide portion 12a may be arranged at intervals or partially overlapped. Each second wide portion 12b corresponds to at least two second light spots 2b, and the plurality of second light spots 2b corresponding to each second wide portion 12b may be arranged at intervals or partially overlapped.

[0116] In the technical solution of this embodiment, preferably, all the first light spots 2a are located at the first wide portions 12a, and the first narrow portions 11a are not directly connected to the first light spots 2a, so it can be designed such that the maximum width of the first narrow portion 11a is less than or equal to the size of the first light spot 2a along the width direction of the first fine grid 1.

[0117] Preferably, all the second light spots 2b are located at the second wide portions 12b. The second narrow portions 11b are not directly connected to the second light spots 2b, so it can be designed such that the maximum width of the second narrow portion 11b is less than or equal to the size of the second light spot 2b along the width direction of the second fine grid 1.

[0118] It should be noted that Figures 1 to 3 only shows the distribution of some of the light spots 2 and does not show all the light spots 2.

[0119] In some embodiments, the maximum width of the first wide portion 12a is greater than the size of the first light spot 2a along the width direction of the first fine grid 1, which can ensure the effect of electrically connecting the first wide portion 12a to the first doping layer 110 through the first light spot 2a. Preferably, to further improve the reliability of the electrical connection between the first fine grid 1a and the first doping layer 110 through the first light spot 2a, the minimum width of the first wide portion 12a is greater than or equal to the size of the first light spot 2a along the width direction of the first fine grid 1.

[0120] In some embodiments, the maximum width of the second wide portion 12b is greater than the dimension of the second light spot 2b along the width direction of the second fine grid 1, which can ensure the effect that the second wide portion 12b is electrically connected to the second doping layer 210 through the second light spot 2b. Preferably, to further improve the reliability of the electrical connection between the second fine grid 1b and the second doping layer 210 through the second light spot 2b, the minimum width of the second wide portion 12b is greater than or equal to the dimension of the second light spot 2b along the width direction of the second fine grid 1.

[0121] The doping concentration of the first doping layer 110 in the first doping region 100 (P region) is lower than that of the second doping layer 210 in the second doping region 200 (N region), resulting in lower conductivity of the first doping region 100. Therefore, more first light spots 2a need to be designed in the first doping region 100. That is, the number of the first light spots 2a is greater than the number of the second light spots 2b. That is to say, when the areas of the first doping region 100 and the second doping region 200 are the same, the distribution density of the first light spots 2a in the first doping region 100 is greater than the distribution density of the second light spots 2b in the second doping region 200.

[0122] In some embodiments, referring to Figure 10 and Figure 11 , the pitch D1 of the first light spots 2a distributed along the length direction of the first fine grid 1a in the first doping region 100 is smaller than the pitch D2 of the second light spots 2b distributed along the length direction of the second fine grid 1b in the second doping region 200.

[0123] The first wide portion 12a of the first fine grid 1a and the first light spots 2a are correspondingly distributed, and the second wide portion 12b of the second fine grid 1b and the second light spots 2b are correspondingly distributed, so that the pitch between two adjacent first wide portions 12a is smaller than the pitch between two adjacent second wide portions 12b. Wherein, the pitch between two adjacent wide portions refers to the distance along the length direction of the fine grid 1 of the gap formed between the two wide portions.

[0124] In some embodiments, the pitch range between adjacent peak points M and valley points N on the first edge line is less than or equal to the pitch range between adjacent peak points M and valley points N on the second edge line.

[0125] In the technical solution of this embodiment, the pitch range between adjacent peak points M and valley points N on any first edge line of the first fine grid 1a is 5 micrometers to 60 micrometers.

[0126] In the technical solution of this embodiment, the pitch range between adjacent peak points M and valley points N on any second edge line of the second fine grid 1b is 5 micrometers to 80 micrometers.

[0127] In the technical solution of this embodiment, the first light spot 2a and the second light spot 2b are circular, square or irregular in shape. The first light spot 2a and the second light spot 2b are collectively referred to as the light spot 2, and the size range of the light spot 2 along the width direction of the corresponding fine grid 1 is 10 microns to 50 microns. In this way, it can be ensured that the wide part 12 of the fine grid 1 can overlap with the light spot 2 as much as possible, and the number of light spots 2 located outside the fine grid 1 can also be reduced.

[0128] In the technical solution of this embodiment, each first wide part 12a of the first fine grid 1a is correspondingly arranged with a first light spot 2a, and each second wide part 12b of the second fine grid 1b is correspondingly arranged with a second light spot 2b; the center distance between two adjacent first light spots 2a is less than the center distance between two adjacent second light spots 2b. In some embodiments, the center distance range between two adjacent first light spots 2a is 40 microns to 120 microns. The center distance range between two adjacent second light spots 2b is 80 microns to 160 microns.

[0129] After the light spot 2 is formed on the passivation layer by laser drilling and then the fine grid 1 is formed by coating, due to some possible processing errors, after the fine grid 1 is completed, there may be some positions where part of the light spot 2 is completely exposed outside the fine grid 1. In some embodiments, the number of light spots 2 covered by the fine grid 1 is more than the number of light spots 2 not covered by the fine grid 1. In this way, it can be ensured that the fine grid 1 has an effect of collecting carriers.

[0130] It should be noted that the light spots 2 covered by the fine grid 1 include the light spots 2 completely covered by the fine grid 1, and also include the light spots 2 only partially covered by the fine grid 1, and the other part of the partially covered light spot 2 is exposed.

[0131] In the technical solution of this embodiment, within each first doping region 100, the number of first light spots 2a covered by the first fine grid 1a is more than the number of first light spots 2a not covered by the first fine grid 1a.

[0132] Within each second doping region 200, the number of second light spots 2b covered by the second fine grid 1b is more than the number of second light spots 2b not covered by the second fine grid 1b.

[0133] In some embodiments, since the number of first light spots 2a is greater than the number of second light spots 2b, the number of first light spots 2a not covered by the first fine grid 1a in the first doping region 100 is more than the number of second light spots 2b not covered by the second fine grid 1b in the second doping region 200.

[0134] The width pairs of the fine grids 1 located on the back surface can affect the secondary reflection of sunlight on the back surface and the photoelectric conversion efficiency. The width pairs of the fine grids 1 located on the front surface can block the entry of sunlight on the front surface and affect the photoelectric conversion efficiency. To solve this technical problem, the present application has made the following second design solution for the structure of the fine grid 1: The width of the fine grid 1 is less than the size of the light spot 2 along the width direction of the fine grid 1, and the projection of the fine grid 1 on the surface of the solar cell overlaps with a part of the projection of the light spot 2 on the surface of the solar cell.

[0135] It should be noted that, in some embodiments, the structure of the first fine grid 1a adopts the second design solution regarding the structure of the fine grid 1; in some other embodiments, the structure of the second fine grid 1b adopts the second design solution regarding the structure of the fine grid 1; in still some other embodiments, the structures of both the first fine grid 1a and the second fine grid 1b adopt the second design solution regarding the structure of the fine grid 1. When the fine grid 1 described below is the first fine grid 1a, the corresponding light spot 2 is the first light spot 2a, and the corresponding doping layer is the first doping layer 110; when the fine grid 1 described below is the second fine grid 1b, the corresponding light spot 2 is the second light spot 2b, and the corresponding doping layer is the second doping layer 210.

[0136] Reference Figure 8 , in some embodiments, the middle region of the projection of the light spot 2 on the back surface overlaps with the projection of the fine grid 1 on the back surface. The size of the light spot 2 along the width direction of the fine grid 1 is greater than the width of the fine grid 1. The overall width of the fine grid 1 is reduced, and the coincidence of the projection of the fine grid 1 on the back surface with the middle region of the projection of the light spot 2 on the back surface can ensure the electrical connection between the fine grid 1, the light spot 2, and the doping layer.

[0137] In the solution of this embodiment, the width range of the fine grid 1 is 10 micrometers to 250 micrometers. The size range of the light spot 2 along the width direction of the fine grid 1 is 10 micrometers to 250 micrometers. Preferably, the size range of the light spot 2 along the width direction of the fine grid 1 is 10 micrometers to 50 micrometers, and the width range of the fine grid 1 is 10 micrometers to 50 micrometers.

[0138] Reference Figure 9a and Figure 9b , in some other embodiments, the fine grid 1 includes at least two fine grid portions 13. The multiple fine grid portions 13 are arranged at intervals along the width direction of the fine grid 1, and the projection of each fine grid portion 13 on the back surface overlaps with a part of the projection of the light spot 2 on the back surface. It can be understood that by dividing the fine grid 1 into multiple fine grid portions 13 arranged at intervals, each fine grid portion 13 can be electrically connected to the doping layer through the light spot 2, and there is a gap between adjacent two fine grid portions 13, which can reduce the secondary reflection of light.

[0139] It should be noted that the fine grid part can be as Figure 9a and Figure 9b shown as a strip-shaped rectangle, that is, the edge line of the fine grid part extending along its length direction can also be a straight line. In some other embodiments, the edge line of the fine grid part extending along its length direction can also be an irregular shape.

[0140] Exemplarily, referring to Figure 9a , the number of the fine grid parts 13 is two, and the two fine grid parts 13 respectively cover both ends of the light spot 2 along the width direction of the fine grid 1.

[0141] To ensure that each fine grid part 13 can overlap with the light spot 2, the size of the light spot 2 along the width direction of the fine grid 1 is greater than the distance C between the two fine grid parts 13.

[0142] In this embodiment, to reduce the occupied area of the fine grid 1, the width of the fine grid part 13 is less than the size of the light spot 2 along the width direction of the fine grid 1. Among them, the width range of the fine grid part 13 is 10 micrometers to 100 micrometers. Preferably, the sum of the widths of the two fine grid parts 13 of the fine grid 1 is less than 200 micrometers. Preferably, the size range of the light spot 2 along the width direction of the fine grid 1 is 20 micrometers.

[0143] Exemplarily, referring to Figure 9b , the number of the fine grid parts 13 is three, and the three fine grid parts are arranged at intervals. Two of the fine grid parts 13 respectively cover both ends of the light spot 2 along the width direction of the fine grid 1, and the other fine grid part 13 covers the middle area of the light spot 2. The distance between adjacent two fine grid parts is C. To ensure that each fine grid part 13 can overlap with the light spot 2, the size of the light spot 2 along the width direction of the fine grid 1 is greater than the sum of the width of one fine grid part 13 and 2*C.

[0144] The embodiment of the present invention further provides a battery assembly, and this battery assembly includes the solar cell of the above embodiment. It should be noted that this battery assembly has the same or similar beneficial effects as the above solar cell, and the relevant parts between the two can be referred to each other. To avoid repetition, it will not be elaborated here.

[0145] In this embodiment, multiple solar cells in the battery assembly can be connected in series in sequence to form a battery string, so as to realize the series connection and current collection output of the current. For example, the connection of the battery wafers can be realized by setting solder tapes (bus bars, interconnection bars), conductive backplates and other means.

[0146] It can be understood that in such an embodiment, the battery assembly may further include a metal frame, a backsheet, a photovoltaic glass, and a glue film. The glue film can be filled between the front and back of the solar cell, as well as between the photovoltaic glass and adjacent solar cells. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the glue film can be an EVA glue film or a POE glue film, and the specific selection can be made according to the actual situation, which is not limited here.

[0147] The photovoltaic glass can cover the glue film on the front of the solar cell. The photovoltaic glass can be ultra-white glass, which has a high light transmittance, high transparency, and excellent physical, mechanical, and optical properties. For example, the light transmittance of the ultra-white glass can reach more than 92%, and it can protect the solar cell without significantly affecting the efficiency of the solar cell. At the same time, the glue film can bond the photovoltaic glass and the back-contact solar cell together, and the presence of the glue film can seal and insulate the back-contact solar cell and prevent water and moisture.

[0148] The backsheet can be attached to the glue film on the back of the solar cell. The backsheet can protect and support the solar cell, and has reliable insulation, water resistance, and aging resistance. The backsheet can have multiple choices and is usually tempered glass, plexiglass, aluminum alloy TPT composite glue film, etc. The specific settings can be made according to the specific situation, which is not limited here. The whole composed of the backsheet, the back-contact solar cell, the glue film, and the photovoltaic glass can be arranged on the metal frame. The metal frame is the main external support structure of the entire solar cell assembly and can stably support and install the solar cell assembly. For example, the solar cell assembly can be installed at the required installation position through the metal frame.

[0149] The embodiment of the present invention also provides a photovoltaic system, which includes the battery assembly of the above embodiment. It should be noted that the photovoltaic system has the same or similar beneficial effects as the above solar cell, and the relevant parts between the two can be referred to each other. To avoid repetition, it will not be elaborated here.

[0150] In this embodiment, the photovoltaic system can be applied in a photovoltaic power station, such as a ground power station, a rooftop power station, a water surface power station, etc., or can also be applied to equipment or devices that use solar energy for power generation, such as a user solar power supply, a solar street lamp, a solar vehicle, a solar building, and so on. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be applied in all fields that require solar power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system can include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array can be an array combination of multiple solar cell modules. For example, multiple solar cell modules can form multiple photovoltaic arrays. The photovoltaic arrays are connected to the combiner box, and the combiner box can collect the current generated by the photovoltaic arrays. After the collected current flows through the inverter and is converted into alternating current required by the commercial power grid, it is connected to the commercial power grid to achieve solar power supply.

[0151] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0152] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application.

[0153] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0154] In the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0155] In this application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include direct contact between the first and second features, or may include indirect contact between the first and second features through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is less than that of the second feature.

[0156] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0157] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these changes and modifications.

[0158] As described above, this is the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A solar cell, characterized in that, A doping layer and a passivation layer are sequentially stacked on the back surface of the solar cell in a direction away from the back surface; and / or, a doping layer and a passivation layer are sequentially stacked on the front surface of the solar cell in a direction away from the front surface; The passivation layer is provided with light spots in its thickness direction. Fine grids are arranged on a side of the passivation layer away from the doping layer, and the fine grids cover a part of the light spots; and are electrically connected to the doping layer through the light spots covered by the fine grids; the number of the light spots covered by the fine grids is more than the number of the light spots not covered by the fine grids; The back surface of the solar cell includes a first doping region and a second doping region which are alternately arranged in sequence; or, the front surface and the back surface of the solar cell are respectively provided with a first doping region and a second doping region; The first doping region is provided with a first fine grid and a plurality of first light spots; the first fine grid covers a part of the first light spots; the number of the first light spots covered by the first fine grid is more than the number of the first light spots not covered by the first fine grid; The second doping region is provided with a second fine grid and a plurality of second light spots; the second fine grid covers a part of the second light spots; the number of the second light spots covered by the second fine grid is more than the number of the second light spots not covered by the second fine grid; Wherein, the polarity of the first fine grid is opposite to the polarity of the second fine grid.

2. The solar cell according to claim 1, characterized in that, A plurality of the light spots are arranged at intervals along the length extension direction of the fine grid.

3. The solar cell according to claim 1, characterized in that, The light spots are circular or square or irregular in shape.

4. The solar cell according to claim 1, characterized in that, The size range of the light spots along the width direction of the fine grid is 10 micrometers to 50 micrometers.

5. The solar cell according to claim 1, characterized in that, The number of the first light spots not covered by the first fine grid in the first doping region is more than the number of the second light spots not covered by the second fine grid in the second doping region.

6. The solar cell according to claim 5, characterized in that, The distribution density of the first light spots in the first doping region is greater than the distribution density of the second light spots in the second doping region.

7. The solar cell according to claim 5, wherein, The center distance between two adjacent first light spots is less than the center distance between two adjacent second light spots.

8. The solar cell according to claim 7, characterized in that, The center distance range between two adjacent first light spots is 40 micrometers to 120 micrometers.

9. The solar cell according to claim 7, characterized in that, The center distance range between two adjacent second light spots is 80 micrometers to 160 micrometers.

10. The solar cell according to claim 1, characterized in that, The fine grid includes a narrow part and a wide part, and the narrow part and the wide part are alternately arranged along the length direction of the fine grid and are sequentially connected; the maximum width of the wide part is greater than the maximum width of the narrow part; the wide part correspondingly covers the light spots.

11. The solar cell according to claim 10, wherein Define the projection of the edge of the fine grid extending along its length direction on the front surface or the back surface of the solar cell as an edge line, and the edge line has inflection points, and the inflection points include peak points and valley points; The peak points are located in the wide part, and the peak points are located on the edge line at the maximum width position of the wide part; The valley points are located in the narrow part, and the valley points are located on the edge line at the minimum width position of the narrow part.

12. The solar cell according to claim 11, characterized in that, When the edge line has a plurality of the peak points and a plurality of the valley points, the peak points and the valley points are alternately and spacedly arranged along the length extension direction of the edge line.

13. The solar cell according to claim 12, wherein The transition from the peak point to the valley point is a smooth transition or an arc transition or a step mutation.

14. The solar cell according to claim 11, characterized in that, The inflection point is in the shape of an arc, a straight line or a broken line.

15. The solar cell according to claim 14, characterized in that, When the inflection point is in the shape of an arc, the included angle range formed by the intersection of the tangents of the parts of the edge line on both sides of the inflection point is 30° to 150°. When the inflection point is in the shape of a broken line, the included angle range formed by the parts of the edge line on both sides of the inflection point is 30° to 150°. When the inflection point is in the shape of a straight line, there is a step mutation from the peak point to the trough point.

16. The solar cell according to claim 11, characterized in that, The two edge lines extending along the length direction of the fine grid are symmetrically arranged.

17. The solar cell according to claim 11, characterized in that, The inflection points of the two edge lines extending along the length direction of the fine grid are arranged in a staggered manner.

18. The solar cell according to claim 11, wherein The spacing range between the two edge lines extending along the length direction of the fine grid is 10 microns to 250 microns.

19. The solar cell according to claim 10, wherein, The maximum width of the narrow part is less than or equal to the size of the light spot along the width direction of the fine grid.

20. The solar cell according to claim 10, characterized in that, The maximum width of the wide part is greater than the size of the light spot along the width direction of the fine grid.

21. The solar cell according to claim 10, characterized in that, The minimum width of the wide part is greater than or equal to the size of the light spot along the width direction of the fine grid.

22. The solar cell according to claim 1, characterized in that, The width of the fine grid is less than the size of the light spot along the width direction of the fine grid, and a part of the projection of the fine grid on the surface of the solar cell overlaps with the projection of the light spot on the surface of the solar cell.

23. The solar cell according to claim 22, characterized in that, The middle area of the projection of the light spot on the front or the back overlaps with the projection of the fine grid on the front or the back.

24. The solar cell according to claim 23, characterized in that, The width range of the fine grid is 10 microns to 250 microns.

25. The solar cell according to claim 22, wherein, The fine grid includes at least two fine grid parts, and the multiple fine grid parts are arranged at intervals along the width direction of the fine grid. The projection of each fine grid part on the front or the back overlaps with the projection of the light spot on the front or the back partially.

26. The solar cell according to claim 25, characterized in that, The number of the fine grid parts is two, and the two fine grid parts respectively cover both ends of the light spot along the width direction of the fine grid.

27. The solar cell according to claim 26, characterized in that, The size of the light spot along the width direction of the fine grid is greater than the spacing C between the two fine grid parts.

28. The solar cell according to claim 27, characterized in that, The width range of the fine grid part is 10 microns to 100 microns.

29. The solar cell according to claim 28, characterized in that, The range of the sum of the widths of the two fine grid parts of the fine grid is less than 200 microns.

30. A battery component, characterized in that, A solar cell comprising any one of claims 1 to 29.

31. A photovoltaic system, characterized in that, A battery module comprising the battery module of claim 30.

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