Battery piece screen printing plate structure, battery piece and battery string

Abstract

The utility model relates to the technical field of solar photovoltaic cell assemblies, in particular to a cell piece screen printing plate structure, cell pieces and a cell string. The battery piece screen printing plate structure comprises a plurality of auxiliary grid lines, a plurality of main grid lines and a plurality of fixing structures, the fixing structures are fixed in the main grid lines, and each fixing structure is connected with at least one auxiliary grid line; wiring points are wrapped in the fixing structure, and each main grid line at least comprises two wiring points. The fixing structure is introduced into the battery piece screen printing plate structure, the wiring point can be wrapped in the fixing structure, the wiring point can be fixed to the main grid line through the fixing structure, and therefore the grid breaking risk of the auxiliary grid line in the battery piece can be reduced; in addition, each main grid line can at least comprise a wiring point, the defective product rate of cold solder joint of the battery piece can be effectively reduced to 1.2%, the defective product rate of hidden crack of the battery piece can be effectively reduced to about 0.5%, and therefore the risk of quality problems of the battery piece can be effectively reduced through the battery piece screen printing plate structure.

Description

Technical Field

[0001] The present application relates to the technical field of solar photovoltaic cell assemblies, and in particular to a cell sheet mesh structure, a cell sheet and a cell string. Background Art

[0002] With the rapid development of solar photovoltaic cells and module technologies, there is an increasing need for high-efficiency photovoltaic cells. Therefore, in the current photovoltaic market environment, how to effectively improve the efficiency of photovoltaic cells at the lowest possible cost has become an issue of increasing concern. At present, the cost of photovoltaic cells is mainly reduced by reducing the amount of silver paste used. In order to improve the conversion efficiency of the battery while reducing the cost of silver paste, the current measures are mainly to use more and thinner main grids and fine grids on the battery cells.

[0003] However, there are few changes in the main grid on the battery cell. Currently, the main change is to increase the number of fine grids. The change in the number of fine grids will inevitably lead to a relative change in the connection point (Pad point) on the main grid and the position of the fine grid, which can easily lead to quality problems such as broken grids, hidden cracks, broken pieces, and poor solder joints in the battery cell. Utility Model Content

[0004] The present application provides a battery cell screen structure, a battery cell and a battery string to solve the following technical problem: how to reduce the risk of quality problems in battery cells.

[0005] In the first aspect, the present application provides a battery cell grid structure, which includes multiple auxiliary grid lines, multiple main grid lines and multiple fixed structures, multiple fixed structures are fixed inside the main grid lines, and each of the fixed structures is connected to at least one auxiliary grid line; wiring points are wrapped in the fixed structures, and each of the main grid lines contains at least 2 wiring points.

[0006] Optionally, the length L of the wiring point satisfies: 0.2 mm<L<2 mm, and the width D of the wiring point satisfies: 0.2 mm<D<2 mm.

[0007] Optionally, the shape of the fixing structure includes circle and / or polygon.

[0008] Optionally, the number of the connection points of each main grid line is 4 to 8.

[0009] Optionally, the number of the main grid lines is 6 to 28.

[0010] Optionally, the number of the secondary grid lines is 90 to 500.

[0011] Optionally, the main grid line further includes a harpoon line, which is arranged at at least one end of the main grid line, and the end of the harpoon line is connected to the outer edge of the fixed structure.

[0012] In a second aspect, the present application provides a battery cell, comprising a silicon substrate and the battery cell mesh structure described in the first aspect, wherein the battery cell mesh structure covers at least a portion of the surface of the silicon substrate.

[0013] Optionally, the thickness of the silicon substrate is ≤140 μm.

[0014] In a third aspect, the present application provides a method for preparing the battery cell according to the second aspect, the method comprising:

[0015] Preparing a composite structure on the surface of a silicon substrate to obtain a pretreated silicon substrate;

[0016] Screen printing is performed on the surface of the pre-treated silicon substrate according to the cell sheet screen structure described in the first aspect to obtain a coarse-grade cell sheet;

[0017] The coarse-grade battery cells are sintered and sorted to obtain battery cells.

[0018] In a fourth aspect, the present application provides a battery string, wherein the battery string includes the battery cell described in the second aspect.

[0019] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0020] The embodiment of the present application provides a cell grid structure, the cell grid structure includes multiple secondary grid lines, multiple main grid lines and multiple fixed structures, multiple fixed structures are fixed inside the main grid lines, each of the fixed structures is connected to at least one secondary grid line; the fixed structure is wrapped with wiring points, and each of the main grid lines contains at least 2 wiring points. The fixed structure is introduced into the cell grid structure, and multiple fixed structures can be fixed inside the main grid lines, and each fixed structure is connected to at least one secondary grid line, and the fixed structure can wrap the wiring points, and the fixed structure can be used to fix the wiring points on the main grid lines to avoid the wiring points in the fixed structure changing with the change of the number of secondary grid lines, thereby reducing the risk of grid breakage of the secondary grid lines in the cell; in addition, each main grid line can contain at least 2 wiring points, which can promote the main grid lines and the secondary grid lines to have sufficient contact points, and the sufficient contact points can increase the bonding strength of the main grid lines and the secondary grid lines on the cell, so as to avoid the risk of hidden cracks and fragments in the cell, thereby effectively reducing the risk of quality problems in the cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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.

[0022] 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.

[0023] Figure 1 A schematic diagram of a battery sheet screen structure provided in an embodiment of the present application;

[0024] Figure 2 for Figure 1 Enlarged image of the red frame;

[0025] Figure 3 A schematic diagram of the structure of a main grid line in a cell sheet screen structure provided in an embodiment of the present application;

[0026] Figure 4 A schematic diagram of the structure of a secondary grid line of a cell sheet mesh structure provided in an embodiment of the present application;

[0027] Figure 5 A schematic diagram of the structure of a battery sheet screen provided in Comparative Example 1 of the present application;

[0028] Figure 6 A schematic diagram of the structure of a battery string composed of battery cells provided in an embodiment of the present application;

[0029] Figure 7 A schematic diagram of the structure of a photovoltaic module composed of solar cells provided in an embodiment of the present application;

[0030] Among them, 1-main grid line, 2-fixed structure, 21-connection point, 3-auxiliary grid line, 4-harpoon line. DETAILED DESCRIPTION

[0031] 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.

[0032] It should be noted that all directional indications such as up, down, left, right, front, back, etc. in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0033] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection, a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] It should be noted that, in view of the fact that "the change in the number of fine grids on the cell will inevitably lead to the relative change of the connection point (Pad point) on the main grid and the position of the fine grid", the inventor of the present application found that when the metallization printing of the cell is carried out, the secondary grid line is first printed using the screen of the secondary grid line, and then the main grid is printed using the screen of the main grid line. Therefore, when conventional cells are screen-printed, the secondary grid line needs to avoid the Pad point of the main grid to avoid repeated printing during printing, and the thickness of the repeated printed area is higher than that of other areas of the cell, which can easily cause poor printing (hidden cracks, etc.), and in the welding process of photovoltaic module manufacturing, the repeatedly printed area in the cell is easy to cause cold welding or even hidden cracks during welding. However, in the process of improving efficiency and reducing costs, the number of fine grids is often optimized for the cell, and in order to prevent the fine grid from coinciding with the Pad point on the main grid, it is necessary to fine-tune the position of the Pad point on the main grid line, and if the position of the Pad point of the main grid line is adjusted, it will be difficult for the point on the welding block to press the Pad point during the welding of the photovoltaic module, which can easily cause cold welding during the welding of the photovoltaic module. In addition, if the main grid line pad point and the auxiliary grid line pad point change relatively, the following defects will occur: on the one hand, if the pad point on the main grid is connected to the fine grid, it is easy to have broken grid, hidden cracks or broken pieces during the welding of the battery cell and the transportation of the string after welding; on the other hand, if the position of the pad point on the main grid changes with the change of the number of fine grids, then during the welding process of the battery cell, the pressure point of the welding tool press may not accurately correspond to the pad point of the battery cell, resulting in cold welding of the battery cell. In addition, changing the welding tool press to adapt to the change of the pad point will inevitably increase the additional cost of the photovoltaic cell.

[0035] Figure 1 A schematic structural diagram of a battery sheet screen structure provided by an embodiment of the present application is exemplarily shown;

[0036] Figure 2 It is shown as an example Figure 1 Enlarged image of the red frame;

[0037] Figure 3The schematic diagram of the structure of the main grid line in a cell sheet screen structure provided by an embodiment of the present application is exemplarily shown;

[0038] Figure 4 The schematic diagram of the structure of the secondary grid line of a cell sheet mesh structure provided by an embodiment of the present application is exemplarily shown;

[0039] like Figures 1 to 4 As shown, an embodiment of the present application provides a battery cell mesh structure, which includes multiple auxiliary grid lines 3, multiple main grid lines 1 and multiple fixed structures 2, multiple fixed structures 2 are fixed inside the main grid lines 1, and each of the fixed structures 2 is connected to at least one of the auxiliary grid lines 3; the fixed structures 2 are wrapped with wiring points 21, and each of the main grid lines 1 contains at least two wiring points 21.

[0040] It should be noted that the fixed structure 2 is a metal node fixedly formed by using the connection point 21 between the main grid line 1 and the auxiliary grid line 3 during the screen printing stage.

[0041] In some optional implementations, the length L of the wiring point 21 satisfies: 0.2 mm < L < 2 mm, and the width D of the wiring point 21 satisfies: 0.2 mm < D < 2 mm;

[0042] In these embodiments, the length L of the wiring point 21 can satisfy 0.2mm<L<2mm, and the width of the wiring point 21 can satisfy: 0.2mm<D<2mm, which can ensure that the wiring point 21 has a sufficient area. The wiring point 21 with a sufficient area can effectively connect the main grid line 1 and the auxiliary grid line 3 to improve the bonding strength between the two, thereby avoiding the occurrence of hidden cracks and cold solder joints in the battery cell during the screen printing process.

[0043] The length L of the connection point 21 may be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm or 1.9 mm.

[0044] The width D of the connection point 21 may be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm or 1.9 mm.

[0045] In some optional embodiments, the shape of the fixing structure 2 includes a circle and / or a polygon;

[0046] In these embodiments, the shape of the fixed structure 2 may include a circle and / or a polygon, mainly depending on the actual battery cell preparation requirements. The circular fixed structure 2 can accommodate more auxiliary grid lines 3 combined with the wiring points 21, while the polygonal fixed structure 2 can increase the bonding strength between the auxiliary grid lines 3 and the main grid lines 1.

[0047] It should be noted that the polygonal fixing structure 2 can be a square, a rectangle, a trapezoid or a polygon.

[0048] In some optional embodiments, the number of the wiring points 21 of each busbar 1 is 4 to 8;

[0049] In these embodiments, the number of connection points 21 of each main grid line 1 can be 4 to 8, so that there are sufficient connection points 21 on each main grid line 1. Sufficient connection points 21 can improve the bonding strength between the main grid line 1 and the auxiliary grid line 3 to avoid the risk of hidden cracks and breakage of the battery cell, thereby effectively reducing the risk of quality problems of the battery cell.

[0050] The number of the connection points 21 of each busbar 1 may be 4, 5, 6, 7 or 8.

[0051] In some optional implementations, the number of the main grid lines 1 is 6 to 28;

[0052] In these embodiments, the number of the busbars 1 may be 6 to 28, which can enable the battery cell to have a sufficient number of busbars 1. A sufficient number of busbars 1 can effectively improve the working efficiency of the battery cell.

[0053] The number of the main grid lines 1 can be 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26 or 28.

[0054] In some optional implementations, the number of the secondary grid lines 3 is 90 to 500.

[0055] In these embodiments, the number of the secondary grid lines 3 is 90 to 500, which can enable the battery cell to have a sufficient number of secondary grid lines 3. A sufficient number of secondary grid lines 3 can effectively improve the working efficiency of the battery cell.

[0056] The number of the secondary grid lines 3 may be 90, 100, 150, 200, 250, 300, 350, 400, 450 or 500.

[0057] In some optional embodiments, the main grid line 1 further includes a harpoon line 4 , which is disposed at at least one end of the main grid line 1 , and the end of the harpoon line 4 is connected to the outer edge of the fixed structure 2 .

[0058] Figure 5 The schematic diagram of the structure of a battery cell provided by an embodiment of the present application is exemplarily shown;

[0059] Based on a general inventive concept, an embodiment of the present application provides a battery cell, which includes a silicon substrate and the battery cell mesh structure, and the battery cell mesh structure covers at least a portion of the surface of the silicon substrate.

[0060] The battery cell is realized based on the above-mentioned battery cell mesh structure. The specific results of the battery cell mesh structure can be referred to the above-mentioned embodiments. Since the battery cell adopts part or all of the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0061] It should be noted that, when the cell mesh structure covers the upper and lower surfaces of the silicon substrate, the number of main grid lines 1 of the cell mesh structure can be 6 to 28, preferably 15 to 24; and at this time, the secondary grid lines 3 of the cell mesh structure can be distributed in the form of 90 to 250 front secondary grid lines 3 and 100 to 500 back secondary grid lines 3, preferably 130 to 200 front secondary grid lines 3 and 150 to 250 back secondary grid lines 3.

[0062] In some optional embodiments, the thickness of the silicon substrate is ≤140 μm;

[0063] In these embodiments, the thickness of the silicon substrate may be ≤140 μm, which may ensure that the silicon substrate has sufficient thickness. A silicon substrate with sufficient thickness may improve the tolerance of the screen structure to hidden cracks when the connection point 21 on the main grid line 1 overlaps with the auxiliary grid line 3 .

[0064] It should be noted that the method for preparing the above-mentioned battery cell may include the following steps:

[0065] S1. Preparing a composite structure on the surface of a silicon substrate to obtain a pretreated silicon substrate;

[0066] S2. Screen printing is performed on the surface of the pretreated silicon substrate according to the cell screen structure to obtain a coarse-grade cell;

[0067] S3. Sintering and sorting the coarse-grade battery cells to obtain battery cells.

[0068] It should be noted that the pre-treated silicon substrate may use an N-type silicon wafer, the surface of which has a composite structure of a multi-layer tunneling oxide layer and a polysilicon layer.

[0069] It should be noted that the length of the pretreated silicon substrate can be 75mm-220mm, preferably 75mm-110mm, or 156mm-220mm; the width of the pretreated silicon substrate can be 20mm-220mm, preferably 28mm-35mm, or 52mm-11mm, or 156mm-220mm.

[0070] It should be noted that the specific steps of step S1 include:

[0071] S101. Texturing the surface of an N-type silicon wafer;

[0072] S102. Boron diffusion is performed on the textured surface of the N-type silicon wafer to form a P+ emitter to obtain a silicon substrate containing a PN junction;

[0073] S103. Etching the silicon substrate containing the PN junction to remove the BSG on the surface of the silicon substrate and the PN junction on the back side to obtain a pure silicon substrate;

[0074] S104. Preparing a multilayer tunneling oxide layer and a polysilicon layer structure on the surface of the pure silicon substrate to obtain a functional silicon substrate;

[0075] S105. Preparing a silicon nitride anti-reflection film on the back side of the functional silicon substrate to obtain a first anti-reflection silicon substrate;

[0076] S106. coating the front side of the anti-reflective silicon substrate with an aluminum oxide passivation film to obtain a coated silicon substrate;

[0077] S107. Prepare a silicon nitride anti-reflection film on the front side of the coated silicon substrate to obtain a pretreated silicon substrate.

[0078] Figure 6 A schematic diagram of a structure of a battery string composed of battery cells provided in an embodiment of the present application is exemplarily shown;

[0079] Figure 7 The schematic diagram of the structure of a photovoltaic module composed of solar cells provided in an embodiment of the present application is exemplarily shown;

[0080] Based on a general inventive concept, such as Figure 7 As shown, an embodiment of the present application provides a battery string, and the battery string includes the battery cell.

[0081] The battery string is realized based on the above-mentioned battery cell. The specific structure and composition of the battery cell can refer to the above-mentioned embodiment. Since the battery string adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0082] It should be noted that the battery string can be composed as follows Figure 7 The photovoltaic module structure shown.

[0083] The present application is further described below in conjunction with specific examples. The experimental methods in the following examples that do not specify specific conditions are usually measured according to industry standards; if there are no corresponding industry standards, they are carried out according to common international standards, conventional conditions, or conditions recommended by the manufacturer.

[0084] Example 1

[0085] like Figures 1 to 4 As shown, a cell grid structure includes multiple auxiliary grid lines 3, multiple main grid lines 1 and multiple fixed structures 2. The multiple fixed structures 2 are fixed inside the main grid lines 1, and each fixed structure 2 is connected to at least one auxiliary grid line 3; the fixed structures 2 are wrapped with wiring points 21, and each main grid line 1 contains at least 2 wiring points 21; the cell grid structure contains a total of 384 wiring points 21.

[0086] The length L of the wiring point 21 is 1.0 mm, and the width D of the wiring point 21 is 1.0 mm.

[0087] The fixing structure 2 is circular in shape.

[0088] The number of busbar lines 1 is distributed in such a manner that the number of front busbars is 16 and the number of back busbars is 16.

[0089] The number of secondary grid lines 3 is distributed in such a manner that the number of front grid lines is 160 and the number of back grid lines is 200.

[0090] like Figure 5 As shown, a battery cell includes a silicon substrate and a battery cell mesh structure, wherein the battery cell mesh structure covers at least a portion of the surface of the silicon substrate.

[0091] The thickness of the silicon substrate is 130 μm.

[0092] The length of the silicon substrate is 182 mm, and the width of the silicon substrate is 182 mm.

[0093] Example 2

[0094] Based on the contents disclosed in Example 1, the following operations are further performed:

[0095] The length L of the wiring point 21 is 0.3 mm, and the width D of the wiring point 21 is 0.3 mm.

[0096] The shape of the fixing structure 2 is a square.

[0097] The number of busbars 1 is distributed such that the number of front busbars and the number of back busbars are 15 respectively.

[0098] The number of auxiliary grid lines 3 is distributed in such a manner that the number of front fine grid lines is 130 and the number of back fine grid lines is 150.

[0099] Example 3

[0100] Based on the contents disclosed in Example 1, the following operations are further performed:

[0101] The length L of the connection point 21 is 1.9 mm, and the width D of the connection point 21 is 1.9 mm.

[0102] The shape of the fixing structure 2 is a square.

[0103] The number of main grid lines 1 is 24.

[0104] The number of auxiliary grid lines 3 is distributed in such a manner that the number of front grid lines is 200 and the number of back grid lines is 250.

[0105] Comparative Example 1

[0106] Based on the contents disclosed in Example 1, the following operations are further performed:

[0107] like Figure 5 As shown, a traditional screen structure is used, wherein the number of wiring points 21 is 384, the number of front main grid lines is 16, the number of back main grid lines is 16; and the number of front auxiliary grid lines is 116, and the number of back auxiliary grid lines is 120.

[0108] Comparative Example 2

[0109] Based on the contents disclosed in Example 1, the following operations are further performed:

[0110] The length L of the wiring point 21 is 0.2 mm, and the width D of the wiring point 21 is 0.2 mm.

[0111] Comparative Example 3

[0112] Based on the contents disclosed in Example 1, the following operations are further performed:

[0113] The length L of the wiring point 21 is 2.0 mm, and the width D of the wiring point 21 is 2.0 mm.

[0114] Related experiments and effect data:

[0115] The cell screen structures obtained in each embodiment and each comparative example were collected respectively, and corresponding cells were prepared according to these cell screen structures. Then, the defective rates of false soldering and hidden cracks of these cells were counted, and the results are shown in Table 1.

[0116] Table 1 The defective cell rate corresponding to the cell screen structure of each embodiment and comparative example

[0117]

[0118]

[0119] As can be seen from Table 1, a battery cell mesh structure provided in an embodiment of the present application introduces a fixed structure 2 in the battery cell mesh structure, and multiple fixed structures 2 can be fixed inside the main grid line 1, and each fixed structure 2 is connected to at least one auxiliary grid line 3, and the fixed structure 2 can wrap the wiring point 21, and the fixed structure 2 can be used to fix the wiring point 21 on the main grid line 1 to avoid the wiring point 21 in the fixed structure 2 changing with the number of auxiliary grid lines 3, thereby reducing the risk of broken grid of the auxiliary grid line 3 in the battery cell; in addition, each main grid line 1 can contain at least 2 wiring points 21, which can promote the main grid line 1 and the auxiliary grid line 3 to have sufficient contact points, and sufficient contact points can increase the bonding strength of the main grid line 1 and the auxiliary grid line 3 on the battery cell to avoid the risk of hidden cracks and breakage of the battery cell, and then effectively reduce the defective rate of cold welding of the battery cell to 1.2% and the defective rate of hidden cracks to about 0.5, which shows that the battery cell mesh structure can effectively reduce the risk of quality problems in the battery cell.

[0120] In addition, a battery sheet mesh structure provided in an embodiment of the present application can be used as a battery sheet prepared by the battery sheet mesh structure. Figure 6 The base structure of the battery string shown or Figure 7 In the matrix structure of the photovoltaic module shown.

[0121] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown in the present application, but will conform to the widest scope consistent with the principles and novel features applied for by the present application.

Claims

1. A battery sheet screen structure, characterized in that: The solar cell grid structure comprises a plurality of secondary grid lines (3), a plurality of main grid lines (1) and a plurality of fixed structures (2); the plurality of fixed structures (2) are fixed inside the main grid lines (1), and each of the fixed structures (2) is connected to at least one of the secondary grid lines (3); wiring points (21) are wrapped inside the fixed structures (2), and each of the main grid lines (1) contains at least two of the wiring points (21).

2. The cell sheet screen structure according to claim 1, characterized in that: The length L of the wiring point (21) satisfies: 0.2 mm < L < 2 mm, and the width D of the wiring point (21) satisfies: 0.2 mm < D < 2 mm.

3. The cell sheet screen structure according to claim 1, characterized in that: The shape of the fixing structure (2) includes a circle and / or a polygon.

4. The cell sheet screen structure according to claim 1, characterized in that: The number of the wiring points (21) of each main grid line (1) is 4 to 8.

5. The cell sheet screen structure according to claim 1, characterized in that: The number of the main grid lines (1) is 6 to 28.

6. The cell sheet screen structure according to claim 1, characterized in that: The number of the secondary grid lines (3) is 90 to 500.

7. The cell sheet screen structure according to claim 1, characterized in that: The main grid line (1) also includes a harpoon line (4), which is arranged at at least one end of the main grid line (1), and the end of the harpoon line (4) is connected to the outer edge of the fixed structure (2).

8. A battery cell, characterized in that: The battery cell comprises a silicon substrate and a battery cell mesh structure as claimed in any one of claims 1 to 7, wherein the battery cell mesh structure covers at least a portion of a surface of the silicon substrate.

9. The battery cell according to claim 8, characterized in that: The thickness of the silicon substrate is ≤140 μm.

10. A battery string, characterized in that: The battery string comprises the battery cell according to claim 8 or 9.

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