Battery piece, manufacturing method thereof and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a battery piece and a manufacturing method thereof, and a photovoltaic module, and the battery piece comprises a substrate which comprises a front surface and a back surface which are opposite to each other; the first auxiliary grid and the second auxiliary grid are positioned on the back; the first main grid is electrically connected with the first auxiliary grid, and the second main grid is electrically connected with the second auxiliary grid; the first insulating layer covers part of the surface of the first auxiliary gate; the second insulating layer covers part of the surface of the second auxiliary gate; wherein the distance between the second auxiliary grid directly facing and adjacent to the first bonding pad and the first bonding pad is a first distance L1, the distance between the end part of the second insulating layer covering the second auxiliary grid and the first bonding pad is a second distance L2, L1 is greater than or equal to 7L2 / 6 and less than or equal to 6L2, and / or L1 is greater than or equal to 7L2 / 6 and less than or equal to 6L2 in the second direction. The distance between the first auxiliary grid directly facing and adjacent to the second bonding pad and the second bonding pad is a third distance L3, the distance between the end of the first insulating layer covering the first auxiliary grid and the second bonding pad is a fourth distance L4, L1 is larger than or equal to 7L2 / 6 and smaller than or equal to 6L2, and the performance of the battery piece can be improved.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the photovoltaic field, and in particular to a solar cell and a manufacturing method thereof, and a photovoltaic module. Background Art

[0002] Solar cell power generation is a sustainable source of clean energy. It uses the photovoltaic effect of semiconductor pn junction to convert sunlight into electrical energy.

[0003] In the process of connecting the solar cells in series into a battery string, it is easy for the welding ribbon to deviate and cause the battery string to short-circuit. Therefore, an insulating layer is usually provided to improve the reliability of the photovoltaic module.

[0004] However, how to set the insulating layer becomes a problem that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present disclosure provide a solar cell and a method for manufacturing the same, and a photovoltaic module, which can at least improve the performance of the solar cell.

[0006] According to some embodiments of the present disclosure, on one hand, the embodiments of the present disclosure provide a battery cell, comprising: a substrate, the substrate comprising a front side and a back side opposite to each other; a plurality of first sub-grids and a plurality of second sub-grids arranged alternately and spaced apart along a first direction, the first sub-grids and the second sub-grids being located on the back side of the substrate; a first main grid and a second main grid arranged alternately and spaced apart along a second direction, the first main grid being electrically connected to the plurality of first sub-grids and spaced apart from the second sub-grids, the second main grid being electrically connected to the plurality of second sub-grids and spaced apart from the first sub-grids; a first insulating layer, the first insulating layer at least covering a portion of the surface of the first sub-grid; and a second insulating layer, the second insulating layer at least covering a portion of the surface of the second sub-grid. Surface; wherein, a first soldering pad is provided on the first main grid, and in the second direction, the distance between the second secondary grid directly opposite to and adjacent to the first soldering pad and the first soldering pad is a first distance L1, and the distance between the end of the second insulating layer covering the second secondary grid and the first soldering pad is a second distance L2, 7L2 / 6≤L1≤6L2, and / or, a second soldering pad is provided on the second main grid, and in the second direction, the distance between the first secondary grid directly opposite to and adjacent to the second soldering pad and the second soldering pad is a third distance L3, and the distance between the end of the first insulating layer covering the first secondary grid and the second soldering pad is a fourth distance L4, 7L2 / 6≤L1≤6L2.

[0007] In some embodiments, a first pad is provided on the first main grid, and a height of the first pad is greater than a height of the second insulating layer, and / or a second pad is provided on the second main grid, and a height of the second pad is greater than a height of the first insulating layer.

[0008] In some embodiments, the substrate includes two edge areas arranged along a first direction and a central area located between the two edge areas, and in the second direction, the width of the first insulating layer located in the edge area is greater than the width of the first insulating layer located in the central area, and / or the width of the second insulating layer located in the edge area is greater than the width of the second insulating layer located in the central area.

[0009] In some embodiments, the width of the first insulating layer located in the edge region is 3 mm to 10 mm, and / or the width of the second insulating layer located in the edge region is 3 mm to 10 mm.

[0010] In some embodiments, along the second direction, the first sub-grid includes a first connecting portion and a first discontinuous portion arranged at intervals, and the first discontinuous portion is directly opposite to the second main grid; along the second direction, the second sub-grid includes a second connecting portion and a second discontinuous portion arranged at intervals, and the second discontinuous portion is directly opposite to the first main grid.

[0011] In some embodiments, the first insulating layer covers the end of the first connecting portion close to the first discontinuity, and also covers a portion of the surface of the first discontinuity, exposing the top surface of the second main grid; the second insulating layer covers the end of the second connecting portion close to the second discontinuity, and also covers a portion of the surface of the second discontinuity, exposing the top surface of the first main grid.

[0012] In some embodiments, the first welding pad is provided on the first main grid, and in the second direction, the width of the second discontinuity of the second sub-grid directly opposite to the first welding pad is greater than the width of the second discontinuity of the second sub-grid offset from the first welding pad, and / or, the second welding pad is provided on the second main grid, and in the second direction, the width of the first discontinuity of the first sub-grid directly opposite to the second welding pad is greater than the width of the first discontinuity of the first sub-grid offset from the second welding pad.

[0013] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a method for manufacturing a battery cell, comprising: providing a substrate, the substrate comprising a front side and a back side opposite to each other; forming a plurality of first sub-grids and a plurality of second sub-grids arranged alternately and spaced apart along a first direction, the first sub-grids and the second sub-grids being located on the back side of the substrate; forming a first main grid and a second main grid arranged alternately and spaced apart along a second direction, the first main grid being electrically connected to the plurality of first sub-grids, and the second main grid being electrically connected to the plurality of second sub-grids; forming a first insulating layer, the first insulating layer covering a portion of the surface of the first sub-grid; forming a second insulating layer, the second insulating layer covering a portion of the surface of the second sub-grid; wherein In the embodiment, a first soldering pad is provided on the first main grid, and in the second direction, the distance between the first soldering pad and the second secondary grid which is opposite to and adjacent to the first soldering pad is a first distance L1, and the distance between the first soldering pad and the end of the second insulating layer covering the second secondary grid is a second distance L2, 7L2 / 6≤L1≤6L2, and / or, a second soldering pad is provided on the second main grid, and in the second direction, the distance between the second soldering pad and the first secondary grid which is opposite to and adjacent to the second soldering pad is a third distance L3, and the distance between the second soldering pad and the end of the first insulating layer covering the first secondary grid is a fourth distance L4, 7L2 / 6≤L1≤6L2.

[0014] In some embodiments, a first solder pad is provided on the first main grid, and a second solder pad is provided on the second main grid. Before forming the first insulating layer, the method further includes: forming a protective film, wherein the protective film corresponds to the positions of the first solder pad and the second solder pad; after forming the second insulating layer, the method further includes: removing the protective film and the first insulating layer and the second insulating layer formed on the surface of the protective film.

[0015] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a photovoltaic module, including: a battery string, formed by connecting a plurality of battery cells as described above, or formed by connecting a plurality of battery cells formed by the manufacturing method of the battery cell as described above; a packaging film, used to cover the surface of the battery string; and a cover plate, used to cover the surface of the packaging film facing away from the battery string.

[0016] The technical solution provided by the embodiment of the present disclosure has at least the following advantages: firstly, the first insulating layer and the second insulating layer are provided to avoid short-circuiting the welding strip and the auxiliary grid which does not need to be electrically connected when the battery string is subsequently connected in series, thereby improving the reliability of the process of connecting the battery cells in series into a battery string; and, when there is a first welding pad on the first main grid, the distance between the second auxiliary grid and the first welding pad and the distance between the end of the second insulating layer and the first welding pad are set to satisfy 7L2 / 6≤L1≤6L2, thereby avoiding the distance between the second insulating layer and the first welding pad being too close, thereby avoiding the second insulating layer from expanding to the first main grid when the second insulating layer collapses. On a pad, thereby preventing the second insulating layer from affecting the welding of the first pad and the subsequent welding strip, and at the same time, it can also prevent the distance between the second sub-grid and the first pad from being too large, avoiding affecting the ability of the second sub-grid to collect carriers, thereby improving the performance of the battery cell while avoiding affecting the reliability of the battery cell. Similarly, when there is a second pad on the second main grid, the distance between the first sub-grid and the second pad and the distance between the end of the first insulating layer and the second pad are set to satisfy 7L4 / 6≤L3≤6L4, which can also prevent the first insulating layer from affecting the welding of the second pad and the subsequent welding strip while avoiding affecting the ability of the first sub-grid to collect carriers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A top view of a battery cell provided by an embodiment of the present disclosure;

[0019] Figure 2 A cross-sectional view of a substrate provided in accordance with an embodiment of the present disclosure;

[0020] Figure 3 A top view of a first sub-grid and a second sub-grid provided in an embodiment of the present disclosure;

[0021] Figure 4 A schematic diagram of a partial structure of a battery cell provided in an embodiment of the present disclosure;

[0022] Figure 5 A schematic diagram of a partial structure of another part of a battery cell provided in an embodiment of the present disclosure;

[0023] Figure 6 Another top view of a battery cell provided in one embodiment of the present disclosure;

[0024] Figures 7 to 10 A schematic structural diagram corresponding to each step of a method for manufacturing a battery cell provided in another embodiment of the present disclosure;

[0025] Fig.11 A schematic diagram of a partial three-dimensional structure of a photovoltaic assembly provided by another embodiment of the present disclosure;

[0026] Fig.12 for Fig.11 A schematic diagram of a cross-sectional structure along the cross-sectional direction MM1. DETAILED DESCRIPTION

[0027] From the background technology, it can be known that for back-contact batteries, the positive and negative grid lines of the back-contact batteries are arranged on the back of the battery cell, and the opposite-sex secondary grid corresponding to the main grid will be covered with an insulating layer to avoid short circuit between the welding strip and the opposite-sex secondary grid. The insulating layer may collapse during the formation process or in other subsequent processes, causing the insulating layer to cover the welding pad of the main grid, which will affect the connection between the welding pad and the welding strip, and may cause the connection between the welding strip and the welding pad to be unreliable, and may fall off.

[0028] The disclosed embodiment provides a cell and a method for manufacturing the same, and a photovoltaic module, wherein the first insulating layer and the second insulating layer are provided in the cell to prevent the welding strip from being short-circuited with the auxiliary grid that does not need to be electrically connected when the cell strings are subsequently connected in series, thereby improving the reliability of the process of connecting the cell cells in series to form a cell string; and, when there is a first welding pad on the first main grid, the distance between the second auxiliary grid and the first welding pad and the distance between the end of the second insulating layer and the first welding pad are set to satisfy 7L2 / 6≤L1≤6L2, thereby preventing the distance between the second insulating layer and the first welding pad from being too close, thereby preventing the second insulating layer from collapsing. It extends to the first pad, thereby preventing the second insulating layer from affecting the welding of the first pad and the subsequent welding strip. At the same time, it can also prevent the distance between the second sub-grid and the first pad from being too large, avoiding affecting the ability of the second sub-grid to collect carriers, thereby improving the performance of the battery cell while avoiding affecting the reliability of the battery cell. Similarly, when there is a second pad on the second main grid, the distance between the first sub-grid and the second pad and the distance between the end of the first insulating layer and the second pad are set to satisfy 7L4 / 6≤L3≤6L4, which can also prevent the first insulating layer from affecting the welding of the second pad and the subsequent welding strip while avoiding affecting the ability of the first sub-grid to collect carriers.

[0029] In the description of the embodiments of the present disclosure, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0030] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0032] In the description of the embodiments of the present disclosure, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0033] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description. They 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 limiting the embodiments of the present disclosure.

[0034] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0035] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are magnified for better understanding and ease of description. When describing a component (such as a layer, a film, a region or a substrate) on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as being "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0036] In the description of the embodiments of the present disclosure, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, a film, a region, or a plate is referred to as being "on / located on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may exist in between. In addition, when a component such as a layer, a film, a region, a plate, etc. is "directly located on" another component, or when a component such as a layer, a film, a region, a plate, etc. is located on the surface of another component, it means that no other components are located in between.

[0037] The terms used in the description of the various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the components" are also intended to include plural forms unless the context clearly indicates otherwise. Among them, components include components such as layers, films, regions, or plates.

[0038] The following will describe the various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present disclosure, many technical details are provided in order to enable the reader to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present disclosure can be implemented.

[0039] refer to Figures 1 to 5 , Figure 1 A top view of a battery cell provided in one embodiment of the present disclosure. Figure 2 A cross-sectional view of a substrate provided in one embodiment of the present disclosure, Figure 3 A top view of a first sub-grid and a second sub-grid provided in an embodiment of the present disclosure, Figure 4 It is a partial structural schematic diagram of a battery cell provided in an embodiment of the present disclosure. Figure 5FIG. 1 is a schematic diagram of a partial structure of another part of a battery cell provided in an embodiment of the present disclosure. It should be noted that, for the sake of clarity, Figure 3 The first main grid, the second main grid, the first insulating layer and the second insulating layer are hidden. Figure 4 Only the first pad, the second sub-gate and the second insulating layer are shown. Figure 5 Only the second pad, the first sub-gate and the first insulating layer are shown schematically.

[0040] In some embodiments, the battery cell may include a substrate 100 including a front side 110 and a back side 120 opposite to each other.

[0041] The cell may further include: a plurality of first sub-grids 101 and a plurality of second sub-grids 102 arranged alternately and spaced apart along the first direction X, and the first sub-grids 101 and the second sub-grids 102 are located on the back side 120 of the substrate 100 .

[0042] The battery cell may also include: a first main grid 103 and a second main grid 104 alternately arranged along the second direction Y, the first main grid 103 is in contact with and electrically connected to a plurality of first auxiliary grids 101 and spaced apart from the second auxiliary grid 102, and the second main grid 104 is in contact with and electrically connected to a plurality of second auxiliary grids 102 and spaced apart from the first auxiliary grid 101.

[0043] The cell may further include: a first insulating layer 105 , the first insulating layer 105 at least covering a portion of the surface of the first sub-grid 101 .

[0044] The battery cell may further include: a second insulating layer 106, the second insulating layer 106 at least covering a portion of the surface of the second auxiliary grid 102, wherein a first pad 113 is provided on the first main grid 103, and in the second direction Y, the distance between the second auxiliary grid 102 directly opposite to and adjacent to the first pad 113 and the first pad 113 is a first distance L1, and the distance between the end of the second insulating layer 106 covering the second auxiliary grid 102 and the first pad 113 is a second distance L2, 7L2 / 6≤L1≤6L2, and / or, a second pad 114 is provided on the second main grid 104, and in the second direction Y, the distance between the first auxiliary grid 101 directly opposite to and adjacent to the second pad 114 and the second pad 114 is a third distance L3, and the distance between the end of the first insulating layer 105 covering the first auxiliary grid 101 and the second pad 114 is a fourth distance L4, 7L4 / 6≤L3≤6L4.

[0045] The embodiment of the present disclosure provides a first insulating layer 105 and a second insulating layer 106 in the battery cell, so that when the battery cells are subsequently connected in series, the welding strip can be prevented from being short-circuited with the auxiliary grid that does not need to be electrically connected, thereby improving the reliability of the process of connecting the battery cells in series to form a battery string; and when there is a first soldering pad 113 on the first main grid 103, the distance between the second auxiliary grid 102 and the first soldering pad 113 and the distance between the end of the second insulating layer 106 and the first soldering pad 113 are set to satisfy 7L2 / 6≤L1≤6L2, which can avoid the distance between the second insulating layer 106 and the first soldering pad 113 being too close, thereby avoiding the second insulating layer 106 from expanding onto the first soldering pad 113 when the second insulating layer 106 collapses. This can prevent the second insulating layer 106 from affecting the welding of the first pad 113 and the subsequent welding strip. At the same time, it can also prevent the distance between the second sub-grid 102 and the first pad 113 from being too large, avoiding affecting the ability of the second sub-grid 102 to collect carriers, thereby improving the performance of the battery cell while avoiding affecting the reliability of the battery cell. Similarly, when there is a second pad 114 on the second main grid 104, the distance between the first sub-grid 101 and the second pad 114 and the distance between the end of the first insulating layer 105 and the second pad 114 are set to satisfy 7L4 / 6≤L3≤6L4, which can also prevent the first insulating layer 105 from affecting the welding of the second pad 114 and the subsequent welding strip while avoiding affecting the ability of the first sub-grid 101 to collect carriers.

[0046] For the substrate 100, the substrate 100 may be formed with a velvet structure, and the substrate 100 may include a substrate 130, and a front passivation layer 140 is formed on the front side 110 of the substrate 130, and a first doping region 150 and a second doping region 160 are formed on the back side 120 of the substrate 130, wherein the first doping region 150 may be doped with doping ions of the same conductivity type as the substrate 130, and the second doping region 160 may have doping ions of a different conductivity type from the substrate 130. For example, the substrate 130 is an N-type substrate 130, the first doping region 150 is an N-type doping region, and the second doping region 160 is a P-type doping region.

[0047] The base 100 may further have a back passivation layer 170 formed on the back side 120 of the substrate 130 . The back passivation layer 170 is located on the surfaces of the first doping region 150 and the second doping region 160 . The back passivation layer 170 may include a single-layer film structure or a stacked-layer film structure.

[0048] In other words, the substrate 100 can be formed on the back contact battery, and other structures except the main grid and the auxiliary grid are formed. After the main grid and the auxiliary grid are formed, a complete battery cell structure can be formed. The corresponding structure of the back contact battery will not be repeated here.

[0049] As for the front side 110 and the back side 120 , the front side 110 is the light-receiving side of the cell, for receiving incident light, and the back side 120 of the substrate 100 is the backlight side.

[0050] The first sub-gate 101 is used to be in contact and electrically connected with the first doping region 150 to collect carriers in the first doping region 150 .

[0051] Combined with reference Figure 1 and Figure 3 In some embodiments, along the second direction Y, the first sub-grid 101 includes first connecting portions 111 and first discontinuous portions 121 arranged at intervals, and the first discontinuous portion 121 is directly opposite to the second main grid 104. In other words, the first sub-grid 101 is a discontinuous structure, and a discontinuity is set at the portion directly opposite to the first sub-grid 101 and the second main grid 104. In this way, even if the second main grid 104 penetrates into the surface of the substrate 100 during the formation of the second main grid 104, there will be no contact between the second main grid 104 and the first sub-grid 101, which can further avoid the electrical connection between the second main grid 104 and the first sub-grid 101, thereby further avoiding the short circuit, thereby improving the reliability of the battery cell.

[0052] The second sub-gate 102 is used to be in contact and electrically connected with the second doping region 160 to collect carriers in the second doping region 160 .

[0053] In some embodiments, along the second direction Y, the second sub-grid 102 includes second connecting portions 112 and second discontinuous portions 122 arranged at intervals, and the second discontinuous portions 122 are directly opposite to the first main grid 103. In other words, the second sub-grid 102 is a discontinuous structure, and a discontinuity is provided at the portion where the second sub-grid 102 and the first main grid 103 are directly opposite to each other. In this way, even if the first main grid 103 penetrates into the surface of the substrate 100 during the formation of the first main grid 103, there will be no contact between the first main grid 103 and the second sub-grid 102, which can further avoid the electrical connection between the first main grid 103 and the second sub-grid 102, thereby further avoiding the short circuit, thereby improving the reliability of the battery cell.

[0054] The first main gate 103 is used to be in contact and electrically connected with the first sub-gate 101 , so as to collect carriers on the first sub-gate 101 onto the first main gate 103 and output the carriers through the first main gate 103 .

[0055] In some embodiments, the second sub-grid 102 is a continuous structure along the second direction Y. In other words, the second sub-grid 102 does not have a second discontinuous portion 122. An insulating structure (not shown in the figure) is also provided at the portion corresponding to the second sub-grid 102 and the first main grid 103. This can avoid the first main grid 103 being connected to the first sub-grid 101 and the second sub-grid 102 at the same time when the first main grid 103 is formed, thereby avoiding a short circuit in the battery cell.

[0056] The second main gate 104 is used to be in contact and electrically connected with the second sub-gate 102 , so as to collect carriers on the second sub-gate 102 onto the second main gate 104 and output them through the second main gate 104 .

[0057] In some embodiments, the first sub-grid 101 is a continuous structure along the second direction Y. In other words, the first sub-grid 101 does not have a first discontinuous portion 121, and an insulating structure (not shown in the figure) is also provided at the portion corresponding to the first sub-grid 101 and the second main grid 104, thereby avoiding that when the second main grid 104 is formed, the second main grid 104 is connected to the first sub-grid 101 and the second sub-grid 102 at the same time, thereby avoiding a short circuit in the battery cell.

[0058] The first insulating layer 105 may be formed by printing insulating glue, or by depositing a material with a relative dielectric constant less than 2.8.

[0059] In some embodiments, a second pad 114 is provided on the second main grid 104, and the height of the second pad 114 is greater than the height of the first insulating layer 105. On the one hand, by setting the height of the second pad 114 higher, when the first insulating layer 105 is formed, the first insulating layer 105 can be prevented from covering the surface of the second pad 114, and when the first insulating layer 105 collapses, the first insulating layer 105 can be prevented from collapsing to the surface of the second pad 114, thereby preventing the first insulating layer 105 from affecting the connection between the second pad 114 and the soldering strip. On the other hand, when connecting the second pad 114 to the soldering strip, solder paste is usually coated on the surface of the second pad 114. Setting the height of the second pad 114 higher can prevent the solder paste from flowing to places other than the second pad 114 after melting.

[0060] In some embodiments, the substrate 100 includes two edge areas 180 arranged along a first direction X and a central area 190 located between the two edge areas 180 , and in the second direction Y, the width of the first insulating layer 105 located in the edge areas 180 is greater than the width of the first insulating layer 105 located in the central area 190 . It can be understood that, for the battery cell, the edge area 180 is actually the part located at the edge of the battery, and in the process of forming a battery string, the welding strip located at the edge of the battery cell is usually subjected to force and bent. When the welding strip is bent, it is possible that the welding strip is electrically connected to the adjacent auxiliary grid. For example, the welding strip is a welding strip electrically connected to the second auxiliary grid 102. When the welding strip is connected in series with other battery cells, it may cause the welding strip to be misaligned with the first insulating layer 105, resulting in overlap with the first auxiliary grid 101, causing the battery cell to be abnormal. Therefore, the width of the first insulating layer 105 is increased in the edge area 180 of the battery cell, so that even if the welding strip is bent, there is still the first insulating layer 105 to isolate the welding strip from the first auxiliary grid 101, thereby increasing the reliability of the battery cell.

[0061] In some embodiments, the width of the first insulating layer 105 located in the edge area 180 is 3 mm to 10 mm, for example, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm or 9 mm, etc. For the first insulating layer 105, the larger the width of the first insulating layer 105, the stronger the ability to improve the reliability of the battery cell. However, the larger the width of the first insulating layer 105, the higher the cost of the first insulating layer 105. Moreover, for the welding strip, the offset of the welding strip also has a certain extreme value. Setting a first insulating layer 105 that is too wide will cause a waste of cost. Therefore, setting the width of the first insulating layer 105 located in the edge area 180 to 3 mm to 10 mm improves the reliability of the battery cell while avoiding a waste of cost.

[0062] In some embodiments, the first insulating layer 105 may cover the top surface of the second main gate 104 . By directly setting the first insulating layer 105 to cover the top surface of the second main gate 104 , the process difficulty of forming the first insulating layer 105 can be reduced, and the control of the process of forming the first insulating layer 105 can be reduced.

[0063] In some embodiments, the first auxiliary grid 101 includes a first connecting portion 111 and a first discontinuity 121 arranged at intervals. The first insulating layer 105 covers the top surface of the second main grid 104 and can also make the top surface of the welding strip relatively flat. For example, the welding strip is electrically connected to the second main grid 104. For the second main grid 104, the second main grid 104 is also electrically connected to the second auxiliary grid 102. Therefore, in some positions of the welding strip, there are the second main grid 104 and the second auxiliary grid 102 below the welding strip. If the first insulating layer 105 does not cover the top surface of the second main grid 104, then in some positions of the welding strip, due to the presence of the first discontinuity 121, there is only the second main grid 104 below the welding strip, and there is a certain height difference between the two parts of the welding strip. The first insulating layer 105 is set to cover the top surface of the second main grid 104, and the height of part of the welding strip can also be filled by the first insulating layer 105, thereby reducing the height difference of each part of the welding strip, thereby improving the reliability of the battery cell after forming a battery string.

[0064] refer to Figure 6 , Figure 6 Another top view of a battery cell provided in accordance with an embodiment of the present disclosure.

[0065] In some embodiments, the first auxiliary grid 101 includes first connecting portions 111 and first discontinuous portions 121 arranged at intervals, and the first insulating layer 105 covers the end of the first connecting portion 111 close to the first discontinuous portion 121, and also covers a portion of the surface of the first discontinuous portion 121, exposing the top surface of the second main grid 104. In other words, the first insulating layer 105 is also intermittently arranged. On the one hand, the intermittently arranged first insulating layer 105 can reduce the cost of the first insulating layer 105. At the same time, since the first insulating layer 105 covers a portion of the surface of the first discontinuous portion 121, that is, the first insulating layer 105 covers the side of the first discontinuous portion 121, even if the welding strip is offset, the welding strip will not be electrically connected to the first auxiliary grid 101. On the other hand, by exposing the top surface of the second main grid 104, the reliability of the connection between the welding strip and the second main grid 104 can be increased.

[0066] The first insulating layer 105 may be in contact with the sidewall of the second main gate 104 to expose the top surface of the second main gate 104 , or the first insulating layer 105 may be spaced from the sidewall of the second main gate 104 to expose the top surface of the second main gate 104 .

[0067] Continue to refer Figure 1In some embodiments, a second pad 114 is disposed on the second main grid 104. In the second direction Y, the width of the first discontinuity 121 of the first auxiliary grid 101 directly opposite to the second pad 114 is greater than the width of the first discontinuity 121 of the first auxiliary grid 101 staggered from the second pad 114. In other words, the discontinuity distance of the first auxiliary grid 101 directly opposite to the second pad 114 is greater. For the second pad 114, the width of the second pad 114 is greater than the width of the second main grid 104. If the discontinuity distance of the first auxiliary grid 101 is controlled to remain unchanged, the distance between the first auxiliary grid 101 and the second pad 114 will be reduced, which may result in electrical connection between the first auxiliary grid 101 and the second pad 114. Therefore, the width of the first discontinuity 121 of the first auxiliary grid 101 directly opposite to the second pad 114 is set to be large to make way for the second pad 114, thereby improving the reliability of the battery cell.

[0068] The second insulating layer 106 may be formed by printing insulating glue, or by depositing a material with a relative dielectric constant less than 2.8.

[0069] In some embodiments, a first pad 113 is provided on the first main grid 103, and the height of the first pad 113 is greater than the height of the second insulating layer 106. On the one hand, by setting the height of the first pad 113 higher, when the second insulating layer 106 is formed, the second insulating layer 106 can be prevented from covering the surface of the first pad 113, and when the second insulating layer 106 collapses, the second insulating layer 106 can be prevented from collapsing to the surface of the first pad 113, thereby preventing the second insulating layer 106 from affecting the connection between the first pad 113 and the soldering strip. On the other hand, when connecting the first pad 113 to the soldering strip, solder paste is usually coated on the surface of the pad. Setting the height of the first pad 113 higher can prevent the solder paste from flowing to places other than the first pad 113 after melting.

[0070] In some embodiments, the substrate 100 includes two edge regions 180 arranged along a first direction X and a central region 190 located between the two edge regions 180. In a second direction Y, the width of the second insulating layer 106 located in the edge region 180 is greater than the width of the second insulating layer 106 located in the central region 190. Similarly, for the welding strip electrically connected to the first auxiliary grid 101, the portion located at the edge will also bend when connected in series with other solar cells. Therefore, setting the width of the second insulating layer 106 located in the edge region 180 to be greater than the width of the second insulating layer 106 located in the central region 190 can increase the reliability of the solar cell, so that even if the welding strip is bent, there is still a second insulating layer 106 to separate the welding strip from the second auxiliary grid 102.

[0071] In some embodiments, the width of the second insulating layer 106 located in the edge region 180 is 3 mm to 10 mm, for example, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm or 9 mm, etc. For the second insulating layer 106, the larger the width of the second insulating layer 106, the stronger the ability to improve the reliability of the battery cell, but the larger the width of the second insulating layer 106, the higher the cost of the second insulating layer 106, and for the welding strip, the deviation of the welding strip also has a certain extreme value, and setting a second insulating layer 106 that is too wide will cause a waste of cost. Therefore, setting the width of the second insulating layer 106 located in the edge region 180 to 3 mm to 10 mm improves the reliability of the battery cell while avoiding a waste of cost.

[0072] The second insulating layer 106 may cover the top surface of the first main gate 103 . Directly setting the second insulating layer 106 to cover the top surface of the first main gate 103 may reduce the process difficulty of forming the second insulating layer 106 and the control of the process of forming the second insulating layer 106 .

[0073] In some embodiments, the second sub-grid 102 includes a second connecting portion 112 and a second discontinuous portion 122 arranged at intervals. The second insulating layer 106 covering the top surface of the first main grid 103 can also make the top surface of the welding strip relatively flat, thereby reducing the height difference between the various parts of the welding strip, thereby improving the reliability of the battery cell after forming a battery string. The same or corresponding description can refer to the above description of the first insulating layer 105 and will not be repeated here.

[0074] refer to Figure 6 In some embodiments, the second secondary grid 102 includes second connecting portions 112 and second discontinuous portions 122 arranged at intervals, and the second insulating layer 106 covers the end of the second connecting portion 112 close to the second discontinuous portion 122, and also covers a portion of the surface of the second discontinuous portion 122, exposing the top surface of the first main grid 103. Similarly, the second insulating layer 106 can also be discontinuously arranged, which can reduce the cost of the second insulating layer 106 while increasing the reliability of the battery cell. The same or corresponding description can refer to the above description of the first insulating layer 105, which will not be repeated here.

[0075] The second insulating layer 106 may contact the sidewall of the first main gate 103 to expose the top surface of the first main gate 103 , or the second insulating layer 106 may be spaced from the sidewall of the first main gate 103 to expose the top surface of the first main gate 103 .

[0076] Continue to refer Figure 1In some embodiments, a first pad 113 is disposed on the first main grid 103, and in the second direction Y, the width of the second discontinuity 122 of the second sub-grid 102 directly opposite to the first pad 113 is greater than the width of the second discontinuity 122 of the second sub-grid 102 staggered from the first pad 113. Similarly, the provision of the first pad 113 will also reduce the distance between the second sub-grid 102 and the first pad 113, which may result in electrical connection between the second sub-grid 102 and the first pad 113. Therefore, by providing the second sub-grid 102 to give way to the first pad 113, the electrical connection between the second sub-grid 102 and the first pad 113 is avoided, thereby improving the reliability of the battery cell.

[0077] The embodiment of the present disclosure provides a first insulating layer 105 and a second insulating layer 106 in the battery cell, which can avoid short-circuiting the welding strip and the auxiliary grid that does not need to be electrically connected when the battery string is subsequently connected in series, thereby improving the reliability of the process of connecting the battery cells in series to form a battery string; and when there is a first soldering pad 113 on the first main grid 103, the distance between the second auxiliary grid 102 and the first soldering pad 113 and the distance between the end of the second insulating layer 106 and the first soldering pad 113 are set to meet 7L2 / 6≤L1≤6L2, which can avoid the distance between the second insulating layer 106 and the first soldering pad 113 being too close, thereby avoiding the second insulating layer 106 from expanding onto the first soldering pad 113 when the second insulating layer 106 collapses. This can prevent the second insulating layer 106 from affecting the welding of the first pad 113 and the subsequent welding strip. At the same time, it can also prevent the distance between the second sub-grid 102 and the first pad 113 from being too large, avoiding affecting the ability of the second sub-grid 102 to collect carriers, thereby improving the performance of the battery cell while avoiding affecting the reliability of the battery cell. Similarly, when there is a second pad 114 on the second main grid 104, the distance between the first sub-grid 101 and the second pad 114 and the distance between the end of the first insulating layer 105 and the second pad 114 are set to satisfy 7L4 / 6≤L3≤6L4, which can also prevent the first insulating layer 105 from affecting the welding of the second pad 114 and the subsequent welding strip while avoiding affecting the ability of the first sub-grid 101 to collect carriers.

[0078] Another embodiment of the present disclosure further provides a method for manufacturing a battery cell, which can be used to form the above-mentioned battery cell. The method for manufacturing a battery cell provided by another embodiment of the present disclosure will be described in detail below in conjunction with the accompanying drawings. It should be noted that the parts that are the same or corresponding to the above-mentioned embodiments will not be repeated below.

[0079] refer to Figures 7 to 10 and Figure 1 , Figures 7 to 10 and Figure 1 This is a schematic structural diagram corresponding to each step of a method for manufacturing a battery cell provided in another embodiment of the present disclosure.

[0080] refer to Figure 7 , Figure 7 In some embodiments, a method for manufacturing a battery cell may include: providing a substrate 100 , wherein the substrate 100 includes a front side 110 and a back side 120 opposite to each other.

[0081] The substrate 100 may be a back contact battery having other structures except the main grid and the auxiliary grid formed therein. For the corresponding description, reference may be made to the description in the above-mentioned battery cell, which will not be repeated here.

[0082] refer to Figure 8 , Figure 8 For Figure 7 The manufacturing method of the cell may include: forming a plurality of first sub-grids 101 and a plurality of second sub-grids 102 alternately arranged along a first direction X, wherein the first sub-grids 101 and the second sub-grids 102 are located on the back side 120 of the substrate 100 .

[0083] The first sub-grid 101 may be formed first by screen printing, and then the second sub-grid 102 may be formed, or the first sub-grid and the second sub-grid may be formed in the same process step.

[0084] refer to Fig. 9 , Fig. 9 For Figure 8 The manufacturing method of the battery cell may include: forming a first main grid 103 and a second main grid 104 arranged alternately along the second direction Y, the first main grid 103 is in contact and electrically connected with a plurality of first auxiliary grids 101, the second main grid 104 is in contact and electrically connected with a plurality of second auxiliary grids 102, and a first pad 113 is provided on the first main grid 103.

[0085] Similarly, the first main grid 103 may be formed first and then the second main grid 104 may be formed by screen printing.

[0086] refer to Fig.10 , Fig.10 exist Fig. 9In some embodiments, a first pad 113 is provided on the first main grid 103, a second pad 114 is provided on the second main grid 104, and before forming the first insulating layer 105, the following steps further include: forming a protective film 107, the protective film 107 corresponding to the positions of the first pad 113 and the second pad 114; and after forming the second insulating layer 106, the following steps further include: removing the protective film 107 and the first insulating layer 105 and the second insulating layer 106 formed on the surface of the protective film 107. In other words, before forming the first insulating layer 105 and the second insulating layer 106, a protective film 107 is first formed at the positions corresponding to the first pad 113 and the second pad 114, so that during the process of forming the first insulating layer 105 and the second insulating layer 106, even if there is a deviation in the process, the materials of the first insulating layer 105 and the second insulating layer 106 will only cover the surface of the protective film 107, thereby preventing the insulating material from covering the surface of the first pad 113 and the second pad 114. Subsequently, the protective film 107 is removed to expose the surface of the first pad 113 and the second pad 114, thereby improving the reliability of the manufacturing method.

[0087] refer to Figure 1 , forming a first insulating layer 105, the first insulating layer 105 covers a portion of the surface of the first auxiliary grid 101; forming a second insulating layer 106, the second insulating layer 106 covers a portion of the surface of the second auxiliary grid 102; wherein a first pad 113 is provided on the first main grid 103, and in the second direction Y, the distance between the second auxiliary grid 102 directly opposite to and adjacent to the first pad 113 and the first pad 113 is a first distance L1, and the end of the second insulating layer 106 covering the second auxiliary grid 102 The distance between the first pad 113 is a second distance L2, 7L2 / 6≤L1≤6L2, and / or, a second pad 114 is provided on the second main grid 104, and in the second direction Y, the distance between the first auxiliary grid 101 that is opposite to and adjacent to the second pad 114 and the second pad 114 is a third distance L3, and the distance between the end of the first insulating layer 105 covering the first auxiliary grid 101 and the second pad 114 is a fourth distance L4, 7L2 / 6≤L1≤6L2.

[0088] By controlling the distance between the second sub-grid 102 and the first pad 113 and the distance between the end of the second insulating layer 106 and the first pad 113 to satisfy 7L2 / 6≤L1≤6L2, and / or controlling the distance between the first sub-grid 101 and the second pad 114 and the distance between the end of the first insulating layer 105 and the second pad 114 to satisfy 7L4 / 6≤L3≤6L4, the first insulating layer 105 or the second insulating layer 106 can be prevented from affecting the subsequent series connection of battery cells, thereby improving the performance of the subsequent battery string.

[0089] Another embodiment of the present disclosure further provides a photovoltaic module, which is used to convert received light energy into electrical energy. The following will describe in detail a method for preparing a solar cell provided by another embodiment of the present disclosure in conjunction with the accompanying drawings. Fig.11 A schematic diagram of a partial three-dimensional structure of a photovoltaic assembly provided by another embodiment of the present disclosure; Fig.12 for Fig.11 A schematic diagram of a cross-sectional structure along the cross-sectional direction MM1. It should be noted that the parts identical or corresponding to the above-mentioned embodiments are not described in detail here.

[0090] refer to Fig.11 and Fig.12 The photovoltaic module includes: a battery string, which is formed by connecting a plurality of battery cells as described in all or part of the above embodiments, or by connecting a plurality of battery cells formed by the manufacturing method of the battery cell as described in all or part of the above embodiments; a packaging film 41, which is used to cover the surface of the battery string; and a cover plate 42, which is used to cover the surface of the packaging film 41 away from the battery string.

[0091] It is worth noting that the cells are electrically connected to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and / or in parallel. The cell may include a sliced ​​cell, and the sliced ​​cell is formed by dividing the whole solar cell, so that the power loss of the photovoltaic module can be improved by the current drop of the sliced ​​cell, so as to improve the photoelectric conversion efficiency of the photovoltaic module.

[0092] In some embodiments, reference Fig.11 , multiple battery strings can be electrically connected through welding ribbons 402. Fig.11 Only one positional relationship between the battery cells is illustrated, that is, the arrangement direction of the electrodes with the same polarity of the battery cells is the same, or the electrodes with positive polarity of each battery cell are arranged toward the same side, so that the welding strip 402 connects different sides of two adjacent battery cells respectively. In some embodiments, the battery cells can also be arranged in the order of electrodes with different polarities facing the same side, that is, the electrodes of multiple adjacent battery cells are arranged in the order of the first polarity, the second polarity, and the first polarity, and then the welding strip 402 connects two adjacent battery cells on the same side.

[0093] In some embodiments, a fixing film is further provided at the edge of the battery cell, and the fixing film abuts against the welding strip 402, thereby improving the stress resistance of the welding strip 402 when different battery cells are connected in series, thereby reducing the possibility of deformation of the welding strip 402, and avoiding overlapping of the opposite-sex secondary grid after the welding strip 402 is deformed, thereby improving the reliability of the formed photovoltaic module.

[0094] In some embodiments, no intervals are set between the battery cells, that is, the battery cells overlap each other.

[0095] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer, the first encapsulation layer covers one of the front side or the back side of the battery cell, and the second encapsulation layer covers the other of the front side or the back side of the battery cell. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene co-elastomer (POE) film or polyethylene terephthalate (PET) film.

[0096] In some cases, there is a boundary between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0097] In some embodiments, the cover plate 42 may be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may be a concave-convex surface, thereby increasing the utilization rate of the incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate is opposite to the first encapsulation layer, and the second cover plate is opposite to the second encapsulation layer.

[0098] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure, so the protection scope of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A battery cell, characterized in that: include: a substrate including opposite front and back surfaces; A plurality of first sub-grids and a plurality of second sub-grids are alternately arranged along a first direction, wherein the first sub-grids and the second sub-grids are located on the back side of the substrate; The first main grid and the second main grid are alternately arranged in a second direction, wherein the first main grid is electrically connected to the first sub-grid contacts and spaced from the second sub-grid, and the second main grid is electrically connected to the second sub-grid contacts and spaced from the first sub-grid; a first insulating layer, wherein the first insulating layer at least covers a portion of a surface of the first sub-grid; a second insulating layer, wherein the second insulating layer at least covers a portion of a surface of the second sub-grid; In which, a first welding pad is provided on the first main grid, and in the second direction, the distance between the second secondary grid which is opposite to and adjacent to the first welding pad and the first welding pad is a first distance L1, and the distance between the end of the second insulating layer covering the second secondary grid and the first welding pad is a second distance L2, 7L2 / 6≤L1≤6L2, and / or, a second welding pad is provided on the second main grid, and in the second direction, the distance between the first secondary grid which is opposite to and adjacent to the second welding pad and the second welding pad is a third distance L3, and the distance between the end of the first insulating layer covering the first secondary grid and the second welding pad is a fourth distance L4, 7L4 / 6≤L3≤6L4.

2. The battery cell according to claim 1, characterized in that: A first pad is disposed on the first main grid, and a height of the first pad is greater than a height of the second insulating layer, and / or a second pad is disposed on the second main grid, and a height of the second pad is greater than a height of the first insulating layer.

3. The battery cell according to claim 1, characterized in that: The substrate includes two edge areas arranged along a first direction and a central area located between the two edge areas. In the second direction, the width of the first insulating layer located in the edge area is greater than the width of the first insulating layer located in the central area, and / or the width of the second insulating layer located in the edge area is greater than the width of the second insulating layer located in the central area.

4. The battery cell according to claim 3, characterized in that: The width of the first insulating layer located in the edge area is 3 mm to 10 mm, and / or the width of the second insulating layer located in the edge area is 3 mm to 10 mm.

5. The battery cell according to claim 1, characterized in that: Along the second direction, the first auxiliary grid includes first connecting portions and first discontinuous portions that are arranged at intervals, and the first discontinuous portion is directly opposite to the second main grid; Along the second direction, the second auxiliary grid includes second connecting portions and second discontinuous portions which are arranged at intervals, and the second discontinuous portions are directly opposite to the first main grid.

6. The battery cell according to claim 5, characterized in that: The first insulating layer covers the end of the first connecting portion close to the first discontinuous portion, and also covers a portion of the surface of the first discontinuous portion, exposing the top surface of the second main grid; The second insulating layer covers the end of the second connecting portion close to the second discontinuous portion, and also covers a portion of the surface of the second discontinuous portion, exposing the top surface of the first main grid.

7. The battery cell according to claim 5, characterized in that: The first welding pad is provided on the first main grid, and in the second direction, the width of the second discontinuous portion of the second sub-grid directly opposite to the first welding pad is greater than the width of the second discontinuous portion of the second sub-grid offset from the first welding pad, and / or, the second welding pad is provided on the second main grid, and in the second direction, the width of the first discontinuous portion of the first sub-grid directly opposite to the second welding pad is greater than the width of the first discontinuous portion of the first sub-grid offset from the second welding pad.

8. A method for manufacturing a battery cell, characterized in that: include: providing a substrate, the substrate comprising opposite front and back surfaces; Forming a plurality of first sub-grids and a plurality of second sub-grids alternately arranged in a first direction, wherein the first sub-grids and the second sub-grids are located on the back side of the substrate; Forming first main grids and second main grids alternately arranged along a second direction, wherein the first main grids are electrically connected to a plurality of the first auxiliary grids, and the second main grids are electrically connected to a plurality of the second auxiliary grids; forming a first insulating layer, wherein the first insulating layer covers a portion of a surface of the first sub-gate; forming a second insulating layer, wherein the second insulating layer covers a portion of a surface of the second sub-grid; In which, a first soldering pad is provided on the first main grid, and in the second direction, the distance between the second secondary grid, which is directly opposite to and adjacent to the first soldering pad, and the first soldering pad is a first distance L1, and the distance between the end of the second insulating layer covering the second secondary grid and the first soldering pad is a second distance L2, 7L2 / 6≤L1≤6L2, and / or, a second soldering pad is provided on the second main grid, and in the second direction, the distance between the first secondary grid, which is directly opposite to and adjacent to the second soldering pad, and the second soldering pad is a third distance L3, and the distance between the end of the first insulating layer covering the first secondary grid and the second soldering pad is a fourth distance L4, 7L2 / 6≤L1≤6L2.

9. The method for manufacturing a battery cell according to claim 8, characterized in that: A first pad is provided on the first main grid, a second pad is provided on the second main grid, and before forming the first insulating layer, the method further includes: forming a protective film, wherein the protective film corresponds to positions of the first pad and the second pad; After forming the second insulating layer, the method further includes: removing the protective film and the first insulating layer and the second insulating layer formed on the surface of the protective film.

10. A photovoltaic module, characterized in that: include: A battery string, formed by connecting a plurality of battery cells as claimed in any one of claims 1 to 7, or a plurality of battery cells as claimed in any one of claims The battery cells formed by the battery cell manufacturing method described in any one of claims 8 to 9 are connected; A packaging film, used to cover the surface of the battery string; The cover plate is used to cover the surface of the packaging film away from the battery string.

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