Solar cell, cell module and photovoltaic system

Abstract

The invention relates to the photovoltaic field, in particular to a solar cell, a cell module and a photovoltaic system, and the back surface of the solar cell is sequentially provided with a doping layer and a passivation layer in a stacked mode in the 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 the direction away from the front surface; the passivation layer is provided with a light spot along the thickness direction, and the fine grid is arranged on one side, deviating from the doping layer, of the passivation layer and is electrically connected with the doping layer through the light spot; the fine grid covers part or all of the light spots; the number of the light spots covered by the fine grids is larger than that of the light spots not covered by the fine grids. Therefore, it can be ensured that enough light spots are electrically connected with the fine grids, and the photoelectric conversion effect of the solar cell can be ensured.

Description

Technical Field

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

[0002] Solar cells are devices that convert sunlight into electrical energy through the photoelectric effect. They are a clean, renewable energy technology. Solar cells include single-sided cells and double-sided cells. Single-sided cells refer to cells where the positive and negative electrodes are both located on the back of the cell, so that the front surface is completely free from the obstruction of the metal grid. Double-sided cells refer to cells where the positive and negative electrodes are located on the front and back of the cell, respectively.

[0003] The surface of the cell is provided with a doping layer and a passivation layer in sequence. A laser is used to open a hole in the passivation layer to form a laser spot, and then a fine grid is coated on the passivation layer. The fine grid passes through the spot, so that the fine grid is electrically connected to the doping layer through the spot. In related technologies, the distribution relationship between the spot and the fine grid affects the photoelectric conversion effect of the solar cell. Summary of the invention

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

[0005] In a first aspect, the present application provides a solar cell, wherein a doping layer and a passivation layer are sequentially stacked on the back side of the solar cell in a direction away from the back side; and / or a doping layer and a passivation layer are sequentially stacked on the front side of the solar cell in a direction away from the front side; The passivation layer is provided with a light spot along its thickness direction; the fine grid is provided on a side of the passivation layer away from the doping layer and is electrically connected to the doping layer through the light spot; the fine grid covers part or all of the light spot; the number of the light spots covered by the fine grid is greater than the number of the light spots not covered by the fine grid.

[0006] Furthermore, the plurality of light spots are arranged at intervals along the length extension direction of the fine grid.

[0007] Furthermore, the light spot is circular, square or irregular in shape.

[0008] Furthermore, the size of the light spot along the width direction of the fine grid ranges from 10 microns to 50 microns.

[0009] Furthermore, the back side of the solar cell comprises a first doping region and a second doping region which are alternately arranged in sequence; or, the front side and the back side of the solar cell are respectively provided with the first doping region and the 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 part or all of the first light spots; the number of the first light spots covered by the first fine grid is greater 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 part or all of the first light spots; the number of the second light spots covered by the second fine grid is greater than the number of the second light spots not covered by the second fine grid.

[0010] The polarity of the first fine gate is opposite to the polarity of the second fine gate.

[0011] Further, the number of the first light spots not covered by the first fine gate in the first doping region is greater than the number of the second light spots not covered by the second fine gate in the second doping region.

[0012] Furthermore, a distribution density of the first light spots in the first region is greater than a distribution density of the second light spots in the second region.

[0013] Furthermore, a center distance between two adjacent first light spots is smaller than a center distance between two adjacent second light spots.

[0014] Furthermore, the center distance between two adjacent first light spots ranges from 40 micrometers to 120 micrometers.

[0015] Furthermore, the center distance between two adjacent second light spots ranges from 80 micrometers to 160 micrometers.

[0016] Furthermore, 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 sequentially connected; the maximum width of the wide portion is greater than the maximum width of the narrow portion; and the wide portion corresponds to and covers the light spot.

[0017] Further, a projection of an edge of the fine grid extending along its length direction on the front side or the back side of the solar cell is defined as an edge line, wherein the edge line has an inflection point, and the inflection point includes a crest point and a trough point; The peak point is located at the wide portion, and the peak point is located on the edge line at the maximum width position of the wide portion; The trough point is located at the narrow portion, and the trough point is located on the edge line at the minimum width position of the narrow portion.

[0018] Further, when the edge line has a plurality of the crest points and a plurality of the trough points, the crest points and the trough points are arranged alternately and at intervals along the length extension direction of the edge line.

[0019] Furthermore, the wave crest point to the wave trough point presents a smooth transition or an arc-shaped transition or a step-shaped mutation.

[0020] Furthermore, the inflection point is an arc, a straight line or a broken line.

[0021] Furthermore, when the inflection point is an arc, the angle formed by the intersection of the tangent lines of the edge line located on both sides of the inflection point is in the range of 30° to 150°; When the inflection point is a broken line, the angle formed by the portions of the edge line located on both sides of the inflection point ranges from 30° to 150°; When the inflection point is a straight line, the peak point to the trough point is a step mutation.

[0022] Furthermore, the two edge lines of the fine grid extending along the length direction thereof are symmetrically arranged.

[0023] Furthermore, the inflection points of the two edge lines of the fine grid extending along the length direction thereof are staggered.

[0024] Furthermore, the interval between two edge lines of the fine grid extending along the length direction thereof ranges from 10 micrometers to 250 micrometers.

[0025] Furthermore, the maximum width of the narrow portion is less than or equal to the size of the light spot along the width direction of the fine grid.

[0026] Furthermore, the maximum width of the wide portion is greater than the size of the light spot along the width direction of the fine grid.

[0027] Furthermore, the minimum width of the wide portion is greater than or equal to the size of the light spot along the width direction of the fine grid.

[0028] Further, the width of the fine grid is smaller than the dimension along the width direction of the fine grid, and the projection of the fine grid on the front side or the back side overlaps with a part of the projection of the light spot on the front side or the back side.

[0029] Further, a middle area of ​​a projection of the light spot on the front side or the back side overlaps with a projection of the fine grid on the front side or the back side.

[0030] Furthermore, the width of the fine grid ranges from 10 micrometers to 250 micrometers.

[0031] Furthermore, the fine grid includes at least two fine grid parts, and the plurality of fine grid parts are arranged at intervals along the width direction of the fine grid, and the projection of each fine grid part on the front side or the back side partially overlaps with the projection of the light spot on the front side or the back side.

[0032] Furthermore, 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 fine grid width direction.

[0033] Furthermore, the size of the light spot along the width direction of the fine grid is greater than the interval C between two of the fine grid parts.

[0034] Furthermore, the width of the fine gate portion ranges from 10 micrometers to 100 micrometers.

[0035] Furthermore, the sum of the widths of the two fine grid portions of the fine grid is less than 200 micrometers.

[0036] In a second aspect, the present application provides a battery assembly, comprising the solar cell as described above.

[0037] In a third aspect, the present application provides a photovoltaic system, comprising the battery assembly as described above.

[0038] The above technical solution provided by this application has the following advantages compared with the prior art: In the technical solution of the present application, the number of light spots on the surface of the solar cell covered by the fine grid is greater than the number of light spots not covered by the fine grid, so that a sufficient number of light spots can be ensured to be electrically connected to the fine grid, thereby ensuring the photoelectric conversion effect of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0041] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0042] Figure 1 A schematic diagram of the back side of a solar cell in the first embodiment of the present application; Figure 2 A schematic diagram of the back side of a solar cell in the second embodiment of the present application; Figure 3 A schematic diagram of the back side of a solar cell in the third embodiment of the present application; Figure 4 It is a partial schematic diagram of a first fine grid in which the first edge line presents a step-like mutation in one embodiment of the present application; Figure 5 It is a partial schematic diagram of a first fine grid in which the first edge line presents a step-like mutation in another embodiment of the present application; Figure 6 It is a partial schematic diagram of a first fine grid in which the first edge line is in a pointed sawtooth shape in one embodiment of the present application; Figure 7 It is a partial schematic diagram of a first fine grid having a first edge line in a round-head sawtooth shape in one embodiment of the present application; Figure 8 A schematic diagram of the back side of a solar cell in a fourth embodiment of the present application; Figure 9a A schematic diagram of the back side of a solar cell in the fifth embodiment of the present application; Figure 9b A schematic diagram of the back side of a solar cell in a sixth embodiment of the present application; Fig.10 is a schematic diagram of the distribution of the first light spot in the first doping region; Fig.11 is a schematic diagram of the distribution of the second light spot in the second doping region; Fig.12 A schematic cross-sectional view of a back-contact solar cell.

[0043] Description of reference numerals: Fine gate 1, first fine gate 1a, first narrow portion 11a, first wide portion 12a, second fine gate 1b, second narrow portion 11b, second wide portion 12b, first edge line La, second edge line Lb, crest point M, trough point N, light spot 2, first light spot 2a, second light spot 2b, fine gate portion 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 DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0045] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers 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.

[0046] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are 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 a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0047] First, Figures 1 to 5 A solar cell is provided in an embodiment of the present application. The solar cell includes a substrate 300 . The substrate 300 has a back surface and a front surface opposite to each other.

[0048] The solar cell provided in the present application may be a single-sided cell. Specifically, refer to Fig.12 The solar cell includes a substrate 300, and the substrate 300 has a back side and a front side opposite to each other. The back side is provided with a plurality of first doping regions 100 and second doping regions 200 arranged alternately, the first doping regions 100 are provided with a first doping layer 110, and the second doping regions 200 are provided with a second doping layer 210, and the doping element type in the first doping layer 110 is different from the doping element type in the second doping layer 210, and the front side is located at the front side of the solar cell, and serves as a light receiving surface for receiving incident sunlight.

[0049] For example, an IBC cell (Interdigitated Back Contact) is a single-sided cell. An IBC cell refers to a back-junction back-contact solar cell structure in which the positive and negative metal electrodes are arranged in an interdigitated manner on the backlight side of the cell, where the back junction refers to the PN junction located on the back of the cell. Since the PN junction and metal electrode of the IBC cell are both located on the back of the cell, there is no metal electrode shading on the front, so very high short-circuit current and conversion efficiency can be obtained.

[0050] refer to Fig.12 A first tunneling layer 510 is provided between the first doping layer 110 and the substrate 300, and a second tunneling layer 520 is 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. The tunneling passivation effect of the first tunneling layer 510 and the second tunneling layer 520 may further improve the cell efficiency of the solar cell.

[0051] In some other embodiments, the solar cell provided in the present application may also be a bifacial cell. Specifically, the solar cell includes a substrate 300, and the substrate 300 has a back surface and a front surface that are opposite to each other. The first doping region 100 and the second doping region 200 are respectively arranged 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, and the type of doping elements in the first doping layer 110 is different from the type of doping elements in the second doping layer 210, and the front surface is located on the front surface of the solar cell as a light-receiving surface for receiving incident sunlight.

[0052] In this application, IBC battery is used as an example for explanation.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The first fine gate 1a is prepared and formed on the first passivation layer 410 by printing or coating, so that the first fine gate 1a is connected to the first doping layer 110 through the first light spot 2a. Specifically, the first fine gate 1a includes a first part located on the side of the first passivation layer 410 away from the first doping layer 110 and a second part penetrating into the first light spot 2a. The first part is electrically connected to the first doping layer 110 through the second part, so that the first fine gate 1a can collect and aggregate the current of the solar cell.

[0060] Similarly, a second fine gate 1b is prepared on the second passivation layer 420 by printing or coating, so that the second fine gate 1b is connected to the second doping layer 210 through the second light spot 2b. Specifically, the second fine gate 1b includes a first part located on the side of the second passivation layer 420 away from the second doping layer 210 and a second part running through the second light spot 2b. The first part is electrically connected to the second doping layer 210 through the second part, thereby achieving the effect of the second fine gate 1b collecting and summing the current of the solar cell.

[0061] The material of the first fine grid 1a and the second fine grid 1b may be one or more of tin, aluminum, silver, gold, nickel, molybdenum or copper.

[0062] The width of the fine grid 1 on the back side will affect the secondary reflection of sunlight on the back side, affecting the photoelectric conversion efficiency. The width of the fine grid 1 on the front side will block the entry of sunlight on the front side, affecting the photoelectric conversion efficiency. In order to solve this technical problem, the present application has made a first design scheme for the structure of the fine grid 1: a fine grid 1 is provided on the surface of the solar cell, and the fine grid 1 includes a narrow portion 11 and a wide portion 12, and the narrow portion 11 and the wide portion 12 are alternately arranged along the length direction of the fine grid 1 and are connected in sequence; the maximum width of the wide portion 12 is greater than the maximum width of the narrow portion 11.

[0063] It should be noted that, in some embodiments, the structure of the first fine gate 1a adopts the first design scheme regarding the structure of the fine gate 1; in other embodiments, the structure of the second fine gate 1b adopts the first design scheme regarding the structure of the fine gate 1; in still other embodiments, the structure of the first fine gate 1a and the structure of the second fine gate 1b both adopt the first design scheme regarding the structure of the fine gate 1.

[0064] It should also be noted that when the solar cell is a bifacial cell, the front and back sides 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 is the same as or different from the structure of the second fine grid 1b, and the sizes of the first fine grid 1a on the front side and the second fine grid 1b on the back side can be different or the same.

[0065] refer to 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.

[0066] In some embodiments, the first fine gate 1a located in the first doping region 100 includes a first narrow portion 11a and a first wide portion 12a, and the first narrow portion 11a and the first wide portion 12a are alternately arranged along the length direction of the first fine gate 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.

[0067] In the technical solution of the present application, the first fine grid 1a arranged on the back side 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 smaller than the width of the first wide portion 12a, thereby reducing the area occupied on the back side of the solar cell. That is, the solution of the present application ensures that the first fine grid 1a can be electrically connected to the first doping layer 110 through the first light spot 2a while achieving an overall reduction in the area occupied by the first fine grid 1 on the back side of the solar cell, thereby reducing the shielding and reflection of light by the first fine grid 1a, and improving the photoelectric conversion efficiency.

[0068] Among them, in the present application, the maximum width of the first wide portion 12a is greater than the maximum width of the first narrow portion 11a, which reduces the resistance of the first fine grid, is beneficial to improving the carrier transmission capacity of the first fine grid, and improving the battery fill factor and conversion efficiency.

[0069] In some embodiments, the second fine gate 1b located in the second doping region 200 includes a second narrow portion 11b and a second wide portion 12b, and the second narrow portion 11b and the second wide portion 12b are alternately arranged along the length direction of the second fine gate 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.

[0070] In the technical solution of the present application, the second fine grid 1b arranged on the back side 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 smaller than the width of the second wide portion 12b, thereby reducing the area occupied on the back side of the solar cell. That is, the solution of the present application ensures that the second fine grid 1b can be electrically connected to the second doping layer 210 through the second light spot 2b, while achieving an overall reduction in the area occupied by the second fine grid 1 on the back side of the solar cell, thereby reducing the shielding and reflection of light by the second fine grid 1b, and improving the photoelectric conversion efficiency.

[0071] 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, which reduces the resistance of the second fine gate, is beneficial to improving the carrier transmission capacity of the second fine gate, and improving the battery fill factor and conversion efficiency.

[0072] refer to 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 side of the solar cell as a first edge line, the first edge line has an inflection point, the inflection point includes a crest point M and a trough point N; the crest point M is located at the first wide portion 12a, and the crest point M corresponds to the position of the maximum width of the first wide portion 12a; the trough point N is located at the first narrow portion 11a, and the trough point N corresponds to the position of the minimum width of the first narrow portion 11a.

[0073] A trough point N is provided between two adjacent crest points M, and a crest point M is provided between two adjacent trough points N, so that the crest points M and the trough points N are alternately arranged.

[0074] 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, and the first light spot 2a is located in the first wide portion 12a, which reduces the resistance of the first fine grid, which is beneficial to improving the carrier transmission capacity of the first fine grid, improving the battery filling factor and conversion efficiency. The trough 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 side 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.

[0075] refer to Figure 1 , define the projection of the edge of the second fine grid 1b extending along its length direction on the back side of the solar cell as a second edge line, the second edge line has an inflection point, the inflection point includes a crest point M and a trough point N; the crest point M is located at the second wide portion 12b, and the crest point M corresponds to the position of the maximum width of the second wide portion 12b; the trough point N is located at the first narrow portion 11a, and the trough point N corresponds to the position of the minimum width of the second narrow portion 11b.

[0076] A trough point N is provided between two adjacent crest points M, and a crest point M is provided between two adjacent trough points N, so that the crest points M and the trough points N are alternately arranged.

[0077] 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 larger, and the second light spot 2b is located in the second wide portion 12b, which reduces the resistance of the second fine grid, is conducive to improving the carrier transmission capacity of the second fine grid, improving the battery filling factor and conversion efficiency. 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 side of the solar cell, and does not affect the effect of the second fine grid 1b being electrically connected to the second doping layer 210 through the second light spot 2b.

[0078] In some embodiments, reference Figure 3 and Figure 6 The first edge line is in a pointed sawtooth shape as a whole, and is bent in a broken line at the crest point M, and is also bent in a broken line at the trough point N, and there is a smooth transition from the crest point M to the trough point N. The angle A formed by the portion of the edge line located on both sides of the inflection point (crest point M or trough point N) ranges from 30° to 150°; optionally, the angle A is 30°, 35°, 45°, 60°, 90°, 120°, 130°, 140° or 150°. The second edge line may have the same or different shape as the first edge line.

[0079] In some embodiments, reference Figure 7 The first edge line is in a rounded sawtooth shape as a whole, and is curved at the crest point M and the trough point N. There is a smooth transition from the crest point M to the trough point N. The angle B formed by the intersection of the tangent lines of the edge line on both sides of the inflection point (crest point M or trough point N) ranges from 30° to 150°; optionally, the angle B is 30°, 35°, 45°, 60°, 90°, 120°, 130°, 140° or 150°. The second edge line may have the same or different shape as the first edge line.

[0080] In some embodiments, reference Figure 1 , Figure 2 , Figure 4 and Figure 5 The first edge line and the second edge line are flat-headed serrated as a whole, so that the first narrow portion 11a and the second narrow portion 11b are square as a whole, and the first wide portion 12a and the second wide portion 12b are square as a whole. In this embodiment, the first edge line portion corresponding to the first wide portion 12a and the first narrow portion 11a is a straight line, the second edge line corresponding to the second wide portion 12b and the second narrow portion 11b is a straight line, and the intersection of the first wide portion 12a and the first narrow portion 11a is a step mutation, and the intersection of the second wide portion 12b and the second narrow portion 11b is a step mutation; wherein the position of the first narrow portion 11a corresponding to the intersection of the first wide portion 12a and the first narrow portion 11a is a trough point N, and the position of the first wide portion 12a corresponding to the intersection of the first wide portion 12a and the first narrow portion 11a is a peak point M; the position of the second narrow portion 11b corresponding to the intersection of the second wide portion 12b and the second narrow portion 11b is a trough point N, and the position of the second wide portion 12b corresponding to the intersection of the second wide portion 12b and the second narrow portion 11b is a peak point M.

[0081] in, Figure 1 , Figure 2 and Figure 4 It is shown in the figure as a step mutation along the width direction of the fine gate 1. Figure 5 Another form of step mutation is shown in Fig. Figure 5 The middle edge has a step mutation in a direction which is at an angle to the length direction of the fine gate 1.

[0082] In some embodiments, the first edge line and / or the second edge line may also be some other anisotropic shapes, as long as the shape including the wave crest point M and the wave trough point N is satisfied.

[0083] refer to Figure 1 and Figure 3 In some embodiments, the two first edge lines of each first fine grid 1a along its length direction are symmetrically arranged, that is, the crest point M of one first edge line is arranged corresponding to the crest 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.

[0084] The two second edge lines of each second fine grid 1b along its length direction are symmetrically arranged, that is, the crest point M of one second edge line is arranged corresponding to the crest 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.

[0085] refer to Figure 2 In some embodiments, the inflection points of the two first edge lines of each first fine grid 1a along its length direction are staggered. That is, the crest 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 crest point M of the other first edge line.

[0086] The inflection points of the two second edge lines of each second fine grid 1b along its length direction are staggered, that is, the crest point M of one second edge line corresponds to the trough point N of the other second edge line. The trough point N of one second edge line corresponds to the crest point M of the other second edge line.

[0087] In the technical solution of this embodiment, the spacing between the two first edge lines of each first fine grid 1a along its length direction ranges from 10 microns to 250 microns. It can be understood that the minimum width of the first narrow portion 11a, that is, the width of the first fine grid 1 corresponding to the trough point N, is 10 microns, and the maximum width of the first wide portion 12a, that is, the width of the first fine grid 1 corresponding to the peak point M, is 250 microns. In this way, the overlapping area of ​​the projection of the first fine grid 1a and the first light spot 2a can be ensured, that is, the cross-sectional area of ​​the second part of the first fine grid 1a located in the first light spot 2a is not too small, and the current collection capability of the first fine grid 1a can be guaranteed.

[0088] 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 microns to 50 microns. In this way, the size of the first light spot 2a is designed to be within an appropriate range to avoid the first light spot 2a being too large to affect the structural performance of the passivation layer, and to avoid the first light spot 2a being too small to affect the ability of the first fine grid 1a to collect current.

[0089] In the technical solution of this embodiment, the spacing between the two second edge lines of each second fine grid 1b along its length direction ranges from 10 microns to 250 microns. It can be understood that the minimum width of the second narrow portion 11b, that is, the width of the second fine grid 1 corresponding to the trough point N, is 10 microns, and the maximum width of the second wide portion 12b, that is, the width of the second fine grid 1 corresponding to the peak point M, is 250 microns. In this way, the overlapping area of ​​the second fine grid 1b and the second light spot 2b can be ensured, that is, the cross-sectional area of ​​the second part of the second fine grid 1b located in the second light spot 2b is not too small, and the current collection capacity of the second fine grid 1b can be guaranteed.

[0090] 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 microns to 50 microns. In this way, the size of the second light spot 2b is designed within a suitable range to avoid the second light spot 2b being too large to affect the structural performance of the passivation layer, and to avoid the second light spot 2b being too small to affect the ability of the second fine grid 1b to collect current.

[0091] In the technical solution of this embodiment, reference 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 arranged alternately. 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 arranged alternately.

[0092] There are multiple second light spots 2b, and the multiple 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 a second light spot 2b.

[0093] In some embodiments, each first wide portion 12a corresponds to a first light spot 2a, and each second wide portion 12b corresponds to a second light spot 2b.

[0094] In other embodiments, each first wide portion 12a corresponds to at least two first light spots 2a, and the multiple first light spots 2a corresponding to each first wide portion 12a can be arranged at intervals or partially overlapped. Each second wide portion 12b corresponds to at least two second light spots 2b, and the multiple second light spots 2b corresponding to each second wide portion 12b can be arranged at intervals or partially overlapped.

[0095] In the technical solution of this embodiment, it is preferred that the first light spot 2a is located at the first wide portion 12a, and the first narrow portion 11a is not directly connected to the first light spot 2a, so it can be designed 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 grating 1.

[0096] Preferably, the second light spot 2b is located at the second wide portion 12b. The second narrow portion 11b is not directly connected to the second light spot 2b, so the maximum width of the second narrow portion 11b can be designed to be less than or equal to the size of the second light spot 2b along the width direction of the second fine grating 1.

[0097] It should be noted that Figures 1 to 3 Only part of the light spot 2 distribution is shown, and not all the light spots 2 are shown.

[0098] 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 that the first wide portion 12a is electrically connected to the first doped layer 110 through the first light spot 2a. Preferably, in order to further improve the reliability of the first fine grid 1a being electrically connected to the first doped 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.

[0099] In some embodiments, the maximum width of the second wide portion 12b is greater than the size of the second light spot 2b along the width direction of the second fine grid 1, which can ensure that the second wide portion 12b is electrically connected to the second doped layer 210 through the second light spot 2b. Preferably, in order to further improve the reliability of the second fine grid 1b being electrically connected to the second doped layer 210 through the second light spot 2b, the minimum width of the second wide portion 12b is greater than or equal to the size of the second light spot 2b along the width direction of the second fine grid 1.

[0100] The doping concentration of the first doping layer 110 of the first doping region 100 (P region) is lower than the doping concentration of the second doping layer 210 of the second doping region 200 (N region), resulting in lower conductivity of the first doping region 100, so more first light spots 2a need to be designed in the first doping region 100. That is, the number of first light spots 2a is greater than the number of second light spots 2b, that is, 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.

[0101] In some embodiments, reference Fig.10 and Fig.11, a spacing D1 of the first light spots 2a distributed along the length direction of the first fine gate 1a in the first doping region 100 is smaller than a spacing D2 of the second light spots 2b distributed along the length direction of the second fine gate 1b in the second doping region 200 .

[0102] The first wide portion 12a of the first fine grid 1a is distributed correspondingly to the first light spot 2a, and the second wide portion 12b of the second fine grid 1b is distributed correspondingly to the second light spot 2b, so that the spacing between two adjacent first wide portions 12a is smaller than the spacing between two adjacent second wide portions 12b. The spacing between two adjacent wide portions refers to the distance of the gap formed between the two wide portions along the length direction of the fine grid 1.

[0103] In some embodiments, the spacing range between adjacent crest points M and trough points N on the first edge line is less than or equal to the spacing range between adjacent crest points M and trough points N on the second edge line.

[0104] In the technical solution of this embodiment, the distance between adjacent crest points M and trough points N on any first edge line of the first fine grid 1a ranges from 5 micrometers to 60 micrometers.

[0105] In the technical solution of this embodiment, the distance between adjacent crest points M and trough points N on any second edge line of the second fine grid 1b ranges from 5 micrometers to 80 micrometers.

[0106] In the technical solution of this embodiment, the first light spot 2a and the second light spot 2b are circular, square or irregular. The first light spot 2a and the second light spot 2b are collectively referred to as light spots 2, and the size of the light spots 2 along the width direction of the corresponding fine grid 1 ranges from 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 spots 2 as much as possible, and the number of light spots 2 outside the fine grid 1 can also be reduced.

[0107] In the technical solution of this embodiment, each first wide portion 12a of the first fine grating 1a is correspondingly arranged with a first light spot 2a, and each second wide portion 12b of the second fine grating 1b is correspondingly arranged with a second light spot 2b; the center distance between two adjacent first light spots 2a is smaller than the center distance between two adjacent second light spots 2b. In some embodiments, the center distance between two adjacent first light spots 2a ranges from 40 microns to 120 microns. The center distance between two adjacent second light spots 2b ranges from 80 microns to 160 microns.

[0108] After the light spot 2 is formed in the passivation layer by laser opening, the fine grid 1 is then formed by coating. Due to some processing errors, after the fine grid 1 is completed, there may be a part of the light spot 2 completely exposed outside the fine grid 1. In some embodiments, the number of the light spots 2 covered by the fine grid 1 is greater than the number of the light spots 2 not covered by the fine grid 1. In this way, the carrier collection effect of the fine grid 1 can be ensured.

[0109] It should be noted that the light spot 2 covered by the fine grid 1 includes the light spot 2 completely covered by the fine grid 1 and also includes the light spot 2 only partially covered by the fine grid 1 , with another part of the partially covered light spot 2 itself exposed.

[0110] In the technical solution of this embodiment, in each first doping region 100 , the number of the first light spots 2 a covered by the first fine gate 1 a is greater than the number of the first light spots 2 a not covered by the first fine gate 1 a .

[0111] In each second doping region 200 , the number of the second light spots 2 b covered by the second fine gate 1 b is greater than the number of the second light spots 2 b not covered by the second fine gate 1 b .

[0112] In some embodiments, since the number of first light spots 2a is greater than the number of second light spots 2b, the number of the first light spots 2a not covered by the first fine gate 1a in the first doping region 100 is greater than the number of the second light spots 2b not covered by the second fine gate 1b in the second doping region 200.

[0113] The width of the fine grid 1 located on the back side will affect the secondary reflection of sunlight on the back side, affecting the photoelectric conversion efficiency. The width of the fine grid 1 located on the front side will block the entry of sunlight on the front side, affecting the photoelectric conversion efficiency. In order to solve this technical problem, the present application has made the following second design scheme for the structure of the fine grid 1: the width of the fine grid 1 is smaller 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.

[0114] It should be noted that, in some embodiments, the structure of the first fine gate 1a adopts the second design scheme for the structure of the fine gate 1; in other embodiments, the structure of the second fine gate 1b adopts the second design scheme for the structure of the fine gate 1; in still other embodiments, the structure of the first fine gate 1a and the structure of the second fine gate 1b both adopt the second design scheme for the structure of the fine gate 1. When the fine gate 1 described below is the first fine gate 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 gate 1 described below is the second fine gate 1b, the corresponding light spot 2 is the second light spot 2b, and the corresponding doping layer is the second doping layer 210.

[0115] refer to Figure 8 In some embodiments, the projection of the light spot 2 on the back overlaps the projection of the fine grid 1 on the back in the middle area. The size of the light spot 2 along the width direction of the fine grid 1 is larger than the width of the fine grid 1, the width of the fine grid 1 is reduced as a whole, and the projection of the fine grid 1 on the back overlaps the projection of the light spot 2 on the back in the middle area, which can ensure that the fine grid 1 is electrically connected to the doping layer through the light spot 2.

[0116] In the solution of this embodiment, the width of the fine grid 1 ranges from 10 microns to 250 microns. The size of the light spot 2 along the width direction of the fine grid 1 ranges from 10 microns to 250 microns. Preferably, the size of the light spot 2 along the width direction of the fine grid 1 ranges from 10 microns to 50 microns, and the width of the fine grid 1 ranges from 10 microns to 50 microns.

[0117] refer to Figure 9a and Figure 9b In some other embodiments, the fine grid 1 includes at least two fine grid portions 13, and the plurality of 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 partially overlaps with the projection of the light spot 2 on the back surface. It can be understood that the fine grid 1 is divided into a plurality of 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 two adjacent fine grid portions 13, which can reduce the secondary reflection of light.

[0118] It should be noted that the fine grid portion can be Figure 9a and Figure 9b The strip-shaped rectangle shown, that is, the edge line of the fine grid portion extending along its length direction may also be a straight line. In some other embodiments, the edge line of the fine grid portion extending along its length direction may also be an irregular shape.

[0119] For example, reference Figure 9a The number of the fine grid portions 13 is two, and the two fine grid portions 13 respectively cover the two ends of the light spot 2 along the width direction of the fine grid 1.

[0120] To ensure that each fine grid portion 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 interval C between two of the fine grid portions 13 .

[0121] In this embodiment, in order to reduce the area occupied by the fine grid 1, the width of the fine grid portion 13 is smaller than the size of the light spot 2 along the width direction of the fine grid 1. The width of the fine grid portion 13 ranges from 10 microns to 100 microns. Preferably, the sum of the widths of the two fine grid portions 13 of the fine grid 1 is less than 200 microns. Preferably, the size of the light spot 2 along the width direction of the fine grid 1 ranges from 20 microns.

[0122] For example, reference Figure 9b The number of the fine grid portions 13 is three, and the three fine grid portions are arranged at intervals. Two of the fine grid portions 13 cover the two ends of the light spot 2 along the width direction of the fine grid 1, respectively, and the other fine grid portion 13 covers the middle area of ​​the light spot 2. The distance between two adjacent fine grid portions is C. To ensure that each fine grid portion 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 of the fine grid portions 13 and 2*C.

[0123] The embodiment of the present invention further provides a battery assembly, which includes the solar cell of the above embodiment. It should be noted that the battery assembly has the same or similar beneficial effects as the above solar cell, and the relevant parts between the two can be referenced to each other. In order to avoid repetition, they will not be described here.

[0124] In this embodiment, multiple solar cells in the battery assembly can be connected in series in sequence to form a battery string, thereby realizing the series bus output of current. For example, the series connection of battery cells can be realized by setting welding strips (bus bars, interconnecting strips), conductive backplanes, etc.

[0125] It is understandable that in such an embodiment, the battery assembly may also include a metal frame, a back plate, photovoltaic glass and an adhesive film. The adhesive film may be filled between the front and back of the solar cell and the photovoltaic glass, adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the adhesive film may be an EVA adhesive film or a POE adhesive film. The specific selection may be based on actual conditions and is not limited here.

[0126] Photovoltaic glass can cover the adhesive film on the front of the solar cell. The photovoltaic glass can be ultra-white glass, which has high light transmittance, high transparency, and excellent physical, mechanical and optical properties. For example, the light transmittance of ultra-white glass can reach more than 92%, which can protect the solar cell without affecting the efficiency of the solar cell as much as possible. At the same time, the adhesive film can bond the photovoltaic glass and the back contact solar cell together. The presence of the adhesive film can seal and insulate the back contact solar cell and make it waterproof and moisture-proof.

[0127] The backplane can be attached to the adhesive film on the back of the solar cell. The backplane can protect and support the solar cell and has reliable insulation, water resistance and aging resistance. There are multiple options for the backplane, which can usually be tempered glass, organic glass, aluminum alloy TPT composite adhesive film, etc. It can be set according to specific circumstances and is not limited here. The whole composed of the backplane, back contact solar cell, adhesive film and photovoltaic glass can be set on a metal frame. The metal frame serves as 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 location through the metal frame.

[0128] The embodiment of the present invention further 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 referenced to each other. In order to avoid repetition, it will not be repeated here.

[0129] In this embodiment, the photovoltaic system can be applied to photovoltaic power stations, such as ground power stations, rooftop power stations, water power stations, etc., and can also be applied to equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple solar cell modules. For example, multiple solar cell modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid, and then connected to the mains network to realize solar power supply.

[0130] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0131] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0132] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0133] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0134] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0135] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0136] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0137] The above is a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A solar cell, characterized in that: The back side of the solar cell is provided with a doping layer and a passivation layer in sequence along a direction away from the back side; and / or the front side of the solar cell is provided with a doping layer and a passivation layer in sequence along a direction away from the front side; The passivation layer is provided with a light spot along its thickness direction; a fine grid is provided on a side of the passivation layer away from the doping layer and is electrically connected to the doping layer through the light spot; the fine grid covers part or all of the light spot; the number of the light spots covered by the fine grid is greater than the number of the light spots not covered by the fine grid.

2. The solar cell according to claim 1, characterized in that The plurality of 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 spot is circular, square or irregular in shape.

4. The solar cell according to claim 1, characterized in that The size of the light spot along the width direction of the fine grid ranges from 10 microns to 50 microns.

5. The solar cell according to claim 1, characterized in that: The back side of the solar cell comprises a first doping region and a second doping region which are arranged alternately in sequence; or, the front side and the back side of the solar cell are respectively provided with the first doping region and the 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 part or all of the first light spots; the number of the first light spots covered by the first fine grid is greater 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 part or all of the first light spots; the number of the second light spots covered by the second fine grid is greater than the number of the second light spots not covered by the second fine grid; The polarity of the first fine gate is opposite to the polarity of the second fine gate.

6. The solar cell according to claim 5, characterized in that: The number of the first light spots not covered by the first fine gate in the first doping region is greater than the number of the second light spots not covered by the second fine gate in the second doping region.

7. The solar cell according to claim 6, characterized in that: The distribution density of the first light spots in the first area is greater than the distribution density of the second light spots in the second area.

8. The solar cell according to claim 6, characterized in that: The center distance between two adjacent first light spots is smaller than the center distance between two adjacent second light spots.

9. The solar cell according to claim 8, characterized in that: The center distance between two adjacent first light spots ranges from 40 micrometers to 120 micrometers.

10. The solar cell according to claim 8, characterized in that The center distance between two adjacent second light spots ranges from 80 micrometers to 160 micrometers.

11. The solar cell according to claim 1, characterized in that: 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 sequentially connected; the maximum width of the wide portion is greater than the maximum width of the narrow portion; and the wide portion corresponds to and covers the light spot.

12. The solar cell according to claim 11, characterized in that: Define the projection of the edge of the fine grid extending along the length direction thereof on the front side or the back side of the solar cell as an edge line, wherein the edge line has an inflection point, and the inflection point includes a crest point and a trough point; The peak point is located at the wide portion, and the peak point is located on the edge line at the maximum width position of the wide portion; The trough point is located at the narrow portion, and the trough point is located on the edge line at the minimum width position of the narrow portion.

13. The solar cell according to claim 12, characterized in that: When the edge line has a plurality of crest points and a plurality of trough points, the crest points and the trough points are arranged alternately and at intervals along the length extension direction of the edge line.

14. The solar cell according to claim 13, characterized in that: The wave crest point to the wave trough point presents a smooth transition or an arc-shaped transition or a step-like mutation.

15. The solar cell according to claim 12, characterized in that: The inflection point is an arc, a straight line or a broken line.

16. The solar cell according to claim 15, characterized in that: When the inflection point is an arc, the angle formed by the intersection of the tangent lines of the edge line located on both sides of the inflection point is in the range of 30° to 150°; When the inflection point is a broken line, the angle formed by the portions of the edge line located on both sides of the inflection point ranges from 30° to 150°; When the inflection point is a straight line, the peak point to the trough point is a step mutation.

17. The solar cell according to claim 12, characterized in that: The two edge lines of the fine grid extending along the length direction thereof are symmetrically arranged.

18. The solar cell according to claim 12, characterized in that: The inflection points of the two edge lines of the fine grid extending along the length direction thereof are staggered.

19. The solar cell according to claim 11, characterized in that: The spacing between two edge lines of the fine grid extending along the length direction thereof ranges from 10 micrometers to 250 micrometers.

20. The solar cell according to claim 11, characterized in that The maximum width of the narrow portion is less than or equal to the size of the light spot along the width direction of the fine grid.

21. The solar cell according to claim 11, characterized in that The maximum width of the wide portion is greater than the dimension of the light spot along the width direction of the fine grid.

22. The solar cell according to claim 11, characterized in that The minimum width of the wide portion is greater than or equal to a dimension of the light spot along a width direction of the fine grid.

23. The solar cell according to claim 1, characterized in that The width of the fine grid is smaller than the dimension along the width direction of the fine grid, and the projection of the fine grid on the front side or the back side overlaps with a part of the projection of the light spot on the front side or the back side.

24. The solar cell according to claim 23, characterized in that A central region of a projection of the light spot on the front side or the back side overlaps with a projection of the fine grid on the front side or the back side.

25. The solar cell according to claim 24, characterized in that The width of the fine grid ranges from 10 micrometers to 250 micrometers.

26. The solar cell according to claim 23, characterized in that The fine grid includes at least two fine grid parts, and the plurality of fine grid parts are arranged at intervals along the width direction of the fine grid, and the projection of each fine grid part on the front side or the back side partially overlaps with the projection of the light spot on the front side or the back side.

27. The solar cell according to claim 26, characterized in that 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 fine grid width direction.

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

29. The solar cell according to claim 28, characterized in that The width of the fine gate portion ranges from 10 micrometers to 100 micrometers.

30. The solar cell according to claim 29, characterized in that The sum of the widths of the two fine grid portions of the fine grid is less than 200 micrometers.

31. A battery assembly, characterized in that: Comprising the solar cell according to any one of claims 1 to 30.

32. A photovoltaic system, characterized in that: Comprising a battery assembly as claimed in claim 31.

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