Battery cell and electric device

Abstract

A battery cell and an electric device. The battery cell comprises a positive electrode sheet, a negative electrode sheet, a positive tab, and a negative tab of an electrode assembly. The positive electrode sheet comprises a positive electrode active substance region, and the negative electrode sheet comprises a negative electrode active substance region. In the width direction of the positive electrode sheet, the positive electrode active substance region is provided with a first end and a second end opposite to each other, and the positive tab protrudes from the first end. In the width direction of the negative electrode sheet, the negative electrode active substance region is provided with a first area beyond the first end and a second area beyond the second end. The negative tab is connected to the first area, the width of the first area is E, the width of the second area is C, and E is greater than C. Therefore, more space can be reserved for an electrolyte solution on the tab side of the negative electrode active substance region and the tab side of the positive electrode active substance region of a housing without increasing the volume of the housing, so that the positive electrode sheet and the negative electrode sheet can be fully infiltrated, enabling the battery cell to have good cycling performance and a high volumetric energy density.

Description

Battery cells and electrical equipment Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell and an electrical device. Background Art

[0002] Battery cells are widely used in portable electronic devices, electric vehicles, power tools, drones, energy storage devices, and other fields. As the scope becomes wider and more complex, higher requirements are placed on the energy density of battery cells.

[0003] Summary of the Invention

[0004] The embodiments of the present application provide a battery cell and an electrical device, so that the battery cell has a higher volume energy density.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, which includes an electrode assembly, wherein the electrode assembly includes a positive electrode sheet, a negative electrode sheet, a positive electrode ear and a negative electrode ear, the positive electrode ear is electrically connected to the positive electrode sheet, the negative electrode ear is electrically connected to the negative electrode sheet, the positive electrode sheet includes a positive electrode active material region, and the negative electrode sheet includes a negative electrode active material region; along the width direction of the positive electrode sheet, the positive electrode active material region has a first end and a second end relative to each other, and the positive electrode ear protrudes from the first end; along the width direction of the negative electrode sheet, the negative electrode active material region has a first region exceeding the first end and a second region exceeding the second end, the negative electrode ear is connected to the first region, the width of the first region is E, the width of the second region is C, and E>C.

[0006] In the above technical solution, the positive electrode ear protrudes from the first end of the positive electrode active material area, the corresponding side of the first end is the ear side of the positive electrode active material area, and the corresponding side of the second end is the non-ear side of the positive electrode active material area. The first area of ​​the negative electrode active material area exceeds and the first end, and the negative electrode ear is connected to the first area, the corresponding side of the first area is the ear side of the negative electrode active material area, and the corresponding side of the second area is the non-ear side of the negative electrode active material area. The width E of the first area and the width C of the second area satisfy E>C, that is, the width of the part of the ear side of the negative electrode active material area that exceeds the ear side of the positive electrode active material area is greater than the width of the negative electrode active material area. The non-tab side of the active material zone exceeds the width of the non-tab side of the positive active material zone, so that the position of the electrode assembly in the outer shell of the battery cell can be adjusted so that along the width direction of the positive electrode sheet, the distance between the first end and the wall of the outer shell is greater than the distance between the second end and the wall of the outer shell, thereby achieving that without increasing the volume of the outer shell, the outer shell reserves more space for the electrolyte on the tab side of the negative active material zone and the tab side of the positive active material zone, so that the positive electrode sheet and the negative electrode sheet can be fully infiltrated, so that the battery cell has better cycle performance and the battery cell has a higher volume energy density.

[0007] In some embodiments of the first aspect of the present application, 1.05≤E / C≤10.

[0008] In the above technical solution, if E / C<1.05, the width of the portion of the tab side of the negative electrode active material region that exceeds the tab side of the positive electrode active material region is smaller than the width of the portion of the non-tab side of the negative electrode active material region that exceeds the non-tab side of the positive electrode active material region, then the distance between the first end and the wall of the shell is smaller, and the space reserved for the electrolyte on the tab side of the negative electrode active material region and the tab side of the positive electrode active material region of the shell is smaller, and the risk of the positive electrode sheet and the negative electrode sheet not being fully wetted is greater. If E / C>10, the width of the portion of the tab side of the negative electrode active material region that exceeds the tab side of the positive electrode active material region is much greater than the non-tab side of the negative electrode active material region. If the side exceeds the width of the part of the non-pole ear side of the positive active material area, the distance between the first end and the wall of the shell is too large, and the distance between the second end and the wall of the shell is too small. The shell reserves a large space for the electrolyte on the pole ear side of the negative active material area and the pole ear side of the positive active material area. The electrolyte contained exceeds the requirement for sufficient wetting of the positive and negative electrode sheets, which may result in waste of materials and space. The space reserved for the electrolyte on the non-pole ear side of the negative active material area and the non-pole ear side of the positive active material area is small, which may result in insufficient wetting of the positive and negative electrode sheets on the non-pole ear side of the negative active material area and the non-pole ear side of the positive active material area. Therefore, 1.05≤E / C≤10, the space reserved for electrolyte on the tab side of the negative active material area and the tab side of the positive active material area of ​​the shell, as well as the space reserved for electrolyte on the non-tab side of the negative active material area and the non-tab side of the positive active material area of ​​the shell are relatively reasonable, so that the positive and negative electrode sheets can be fully wetted, so that the battery cell has better cycle performance, and can also reduce material waste, save costs, and reduce the waste of space inside the shell. The space inside the shell is fully utilized to improve the volume energy density of the battery cell.

[0009] In some embodiments of the first aspect of the present application, 1.1≤E / C≤4.

[0010] In the above technical solution, 1.1≤E / C≤4, so that the battery cell has better cycle performance, can further reduce material waste, further save costs, and further reduce the waste of internal space of the shell. The space inside the shell is fully utilized to improve the volume energy density of the battery cell.

[0011] In some embodiments of the first aspect of the present application, the battery cell further includes an insulating member, at least a portion of which is located between the first region and the positive electrode tab.

[0012] In the above technical solution, at least part of the insulating member is located between the first region and the positive electrode ear, which can separate the first region and the positive electrode ear, reduce the risk of burrs on the positive electrode ear piercing the isolation membrane and causing the positive electrode ear and the first region to contact and short-circuit, and improve the safety performance of the battery cell.

[0013] In some embodiments of the first aspect of the present application, along the width direction of the negative electrode sheet, the first region has a third end away from the second region, and the insulating member extends beyond the third end in a direction away from the positive electrode active material region.

[0014] In the above technical solution, in the width direction of the negative electrode sheet, the insulating part extends beyond the third end of the first region away from the second region in the direction away from the positive active material area. The insulating part can not only separate the first region and the positive electrode ear, but also separate the negative electrode ear from the positive electrode ear, which can reduce the risk of burrs on the positive electrode ear and burrs on the negative electrode ear piercing the isolation membrane, causing the positive electrode ear and the negative electrode ear to contact and short-circuit, thereby further improving the safety performance of the battery cell.

[0015] In some embodiments of the first aspect of the present application, along the width direction of the negative electrode sheet, the insulating member has a third region extending beyond the third end, and the width of the third region is F, 0<(E+C) / 2-F≤5mm.

[0016] In the above technical solution, if (E+C) / 2-F>5mm, the width of the insulating member is too large, occupying a large space, which will occupy more space on the tab side to accommodate the electrolyte. There is a greater risk that the positive and negative electrode sheets will not be fully wetted, which is not conducive to the battery cell having a high volume energy density. Therefore, 0<(E+C) / 2-F≤5mm can not only effectively separate the first region and the positive tab, reducing the risk of the positive tab puncturing the separator and causing a short circuit in the battery cell, but also minimize the space on the tab side to accommodate the electrolyte, allowing the positive and negative electrode sheets to be better wetted by the electrolyte, improving the cycle performance of the battery cell, and also conducive to the battery cell having a high volume energy density.

[0017] In some embodiments of the first aspect of the present application, 0.1 mm≤(E+C) / 2-F≤1 mm.

[0018] In the above technical solution, if (E+C) / 2-F<0.1mm, the insulating member cannot effectively separate the first region and the positive electrode ear. 0.1mm≤(E+C) / 2-F≤1mm can not only make the insulating member effectively separate the first region and the positive electrode ear, reduce the risk of the burrs of the positive electrode ear piercing the isolation membrane and causing a short circuit in the battery cell, but also make the battery cell have a better volume energy density.

[0019] In some embodiments of the first aspect of the present application, one end of the insulating member contacts the first end.

[0020] In the above technical solution, one end of the insulating member contacts the first end, which can increase the coverage area of ​​the insulating member, better separate the first area and the positive electrode ear, further reduce the risk of short circuit of the battery cell, and improve the safety performance of the battery cell.

[0021] In some embodiments of the first aspect of the present application, the battery cell further includes a shell, the electrode assembly is accommodated in the shell, the shell has a first wall and a second wall arranged opposite to each other, the first end is arranged facing the first wall, and the second end is arranged facing the second wall; the distance between the first area and the first wall is K1, and the distance between the second area and the second wall is K2, K1>K2.

[0022] In the above technical solution, since the corresponding side of the first end is the pole ear side of the positive active material area, the corresponding side of the second end is the non-pole ear side of the positive active material area, the corresponding side of the first area is the pole ear side of the negative active material area, and the corresponding side of the second area is the non-pole ear side of the negative active material area, K1 and K2 satisfy K1>K2, that is, the distance between the pole ear side of the negative active material area and the wall of the shell is greater than the distance between the non-pole ear side of the negative active material area and the wall of the shell. The shell reserves more space for the electrolyte on the pole ear side of the negative active material area, so that the positive electrode sheet and the negative electrode sheet can be fully infiltrated, so that the battery cell has better cycle performance and the battery cell has a higher volume energy density.

[0023] In some embodiments of the first aspect of the present application, the battery cell further includes an insulating member, at least a portion of which is located between the first region and the positive electrode tab; the insulating member has a fourth end facing the first wall, and the distance between the fourth end and the first wall is K3, K3>K2.

[0024] In the above technical solution, K3>K2, and the shell reserves more space for the electrolyte on the ear side of the positive active material area, so that the positive and negative electrode sheets can be fully infiltrated, thereby making the battery cell have better cycle performance.

[0025] In some embodiments of the first aspect of the present application, the electrode assembly further includes a separator, which is used to separate the positive electrode sheet and the negative electrode sheet. Along the width direction of the positive electrode sheet, the width of the separator extending beyond the first end is L1, and the width of the separator extending beyond the second end is L2. <L1-L2≤8mm。

[0026] In the above technical solution, 0 < L1 - L2, that is, L1 > L2. Since the width E of the negative electrode active material region exceeding the first region at the first end and the width C of the second region exceeding the second end satisfy E > C, thus L1 > L2, so that the width of the part of the separator exceeding the first end and the width of the part of the separator exceeding the second end respectively match the width of the first region and the width of the second region, enabling the separator to better separate the positive electrode sheet and the negative electrode sheet, better alleviating the problem of short circuit of the battery cell, and thus improving the safety performance of the battery cell. If L1 - L2 > 8 mm, the size of the separator in the width direction of the positive electrode sheet is too large, occupying a large space inside the outer shell, which is not conducive to the full wetting of the positive electrode sheet and the negative electrode sheet and the battery cell having a high energy density. Therefore, L1 - L2 ≤ 8 mm, so that the separator can effectively separate the positive electrode sheet and the negative electrode sheet, reduce the risk of short circuit of the battery cell, and can also minimize the size of the separator in the width direction of the positive electrode sheet as much as possible, so that the separator occupies as little space inside the outer shell as possible, and thus there is more space inside the outer shell to accommodate the electrolyte, which is conducive to the full wetting of the positive electrode sheet and the negative electrode sheet, improving the cycle performance of the battery cell, and conducive to the battery cell having a high energy density.

[0027] In some embodiments of the first aspect of the present application, 1 mm ≤ L1 - L2 ≤ 3 mm.

[0028] In the above technical solution, 1 mm ≤ L1 - L2 ≤ 3 mm enables the separator to more effectively separate the positive electrode sheet and the negative electrode sheet, further reducing the risk of short circuit of the battery cell, and can also minimize the size of the separator in the width direction of the positive electrode sheet as much as possible, so that the separator occupies as little space inside the outer shell as possible, and thus there is more space inside the outer shell to accommodate the electrolyte, which is conducive to the full wetting of the positive electrode sheet and the negative electrode sheet, enabling the battery cell to have better cycle performance, and conducive to the battery cell having a high energy density.

[0029] In the second aspect, an electrical device is provided in an embodiment of the present application. The electrical device includes the battery cell provided in any embodiment of the first aspect. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts.

[0031] FIG. 1 is a schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0032] FIG. 2 is a cross-sectional view taken along A1 - A1 in FIG. 1;

[0033] FIG3 is a cross-sectional view taken along line A2-A2 in FIG1 ;

[0034] FIG4 is a schematic diagram of a structure in which a positive electrode sheet, a negative electrode sheet, and a separator are stacked and deployed, according to some embodiments of the present application;

[0035] FIG5 is a view showing a positive electrode sheet, a negative electrode sheet, and a separator provided in some embodiments of the present application stacked and unfolded along the length direction of the positive electrode sheet;

[0036] FIG6 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in some embodiments of the present application (viewed along the thickness direction of the positive electrode sheet);

[0037] FIG7 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in some embodiments of the present application (viewed along the length direction of the positive electrode sheet);

[0038] FIG8 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in other embodiments of the present application (viewed along the thickness direction of the positive electrode sheet);

[0039] FIG9 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in other embodiments of the present application (viewed along the length direction of the positive electrode sheet);

[0040] FIG10 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in some further embodiments of the present application (viewed along the thickness direction of the positive electrode sheet);

[0041] FIG11 is a cross-sectional view taken along line A3-A3 in FIG10 ;

[0042] FIG12 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in some other embodiments of the present application (viewed along the thickness direction of the positive electrode sheet);

[0043] FIG13 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in some other embodiments of the present application (viewed along the length direction of the positive electrode sheet);

[0044] FIG14 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in some other embodiments of the present application (viewed along the thickness direction of the positive electrode sheet);

[0045] FIG15 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in some other embodiments of the present application (viewed along the length direction of the positive electrode sheet);

[0046] FIG16 is a schematic diagram of the connection between the positive electrode sheet and the positive electrode tab provided in still other embodiments of the present application (viewed along the thickness direction of the positive electrode sheet);

[0047] FIG17 is a schematic diagram of a structure in which a positive electrode sheet, a negative electrode sheet, and a separator are stacked and deployed, according to some other embodiments of the present application;

[0048] FIG18 is a view showing a stacked arrangement of a positive electrode sheet, a negative electrode sheet, and a separator in an unfolded state, observed along the length direction of the positive electrode sheet, according to yet other embodiments of the present application;

[0049] FIG19 is a view showing a stacked arrangement of a positive electrode sheet, a negative electrode sheet, and a separator provided in some further embodiments of the present application and in an unfolded state, observed along the length direction of the positive electrode sheet.

[0050] Icons: 100-battery cell; 10-electrode assembly; 11-positive electrode sheet; 111-positive electrode active material area; 1111-first end; 1112-second end; 112-positive electrode current collector; 1121-coated area; 1122-uncoated area; 113-positive electrode active material layer; 12-negative electrode sheet; 121-negative electrode active material area; 1211-first area; 12111-third end; 1212-second area; 122-negative electrode current collector; 123-negative electrode active material layer; 1231-first area Grooving; 13-positive electrode ear; 131-first rivet portion; 132-first limiting portion; 14-negative electrode ear; 15-isolation membrane; 20-insulating member; 21-third region; 30-housing; 31-first wall; 32-second wall; 40-first electrode lead; 50-second electrode lead; X1-width direction of the positive electrode sheet; X2-width direction of the negative electrode sheet; Y1-length direction of the positive electrode sheet; Y2-length direction of the negative electrode sheet; Z1-thickness direction of the positive electrode sheet; Z2-thickness direction of the negative electrode sheet; P-gap. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0052] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0053] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0054] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0055] In the description of the embodiments of the present application, it should be noted that the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are merely for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present application. In addition, the terms "first," "second," "third," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0056] Currently, market developments indicate that battery cells are becoming increasingly widespread. They are used in a wide range of electric vehicles, including electric bicycles, electric motorcycles, and electric vehicles, as well as in power tools, drones, and energy storage devices. As battery cell applications continue to expand, market demand is also growing.

[0057] The battery cell consists of a casing and an electrode assembly, which is housed within the casing. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, separator, and negative electrode sheet are stacked together, with the separator insulating and separating the positive and negative electrodes to reduce the risk of short circuits in the battery cell.

[0058] During the battery cell design process, the width ends of the negative electrode sheet need to extend beyond the width ends of the positive electrode sheet to ensure sufficient space for ions released from the positive electrode sheet to embed, thereby reducing the risk of lithium plating. In conventional wound or laminated electrode assemblies, the width ends of the negative electrode sheet extend substantially equal distances beyond the width ends of the positive electrode sheet. The electrode assembly is typically centered within the housing. Therefore, substantially equal space needs to be reserved on both sides of the negative electrode sheet along its width to reduce the risk of interference between the negative electrode sheet and the housing.

[0059] Typically, the positive tab is connected to one end of the positive electrode sheet, and the negative tab is connected to one end of the negative electrode sheet, extending along the same side. The bending and gluing of the positive and negative tabs requires a relatively large space, which reduces the space available for electrolyte on the tab side of the housing. This can lead to problems such as wetting and poor circulation of the positive and negative tabs. There's even the safety issue of the tab being inserted upside down when the electrode assembly is inserted into the housing. To reserve sufficient electrolyte space and reduce the risk of upside-down tab insertion, the internal space of the housing needs to be increased to create more energy density. This results in an oversized housing, which in turn reduces the volumetric energy density of the battery cell.

[0060] Based on the above considerations, in order to alleviate the problem of low volume energy density of battery cells, an embodiment of the present application provides a battery cell, wherein the electrode assembly of the battery cell includes a positive electrode sheet, a negative electrode sheet, a positive electrode ear and a negative electrode ear, the positive electrode ear is electrically connected to the positive electrode sheet, the negative electrode ear is electrically connected to the negative electrode sheet, the positive electrode sheet includes a positive electrode active material region, and the negative electrode sheet includes a negative electrode active material region; along the width direction of the positive electrode sheet, the positive electrode active material region has a first end and a second end relative to each other, and the positive electrode ear protrudes from the first end; along the width direction of the negative electrode sheet, the negative electrode active material region has a first region exceeding the first end and a second region exceeding the second end, the negative electrode ear is connected to the first region, the width of the first region is E, the width of the second region is C, and E>C.

[0061] The positive electrode ear protrudes from the first end of the positive electrode active material area, the first end corresponding side is the ear side of the positive electrode active material area, the second end corresponding side is the non-ear side of the positive electrode active material area, the first area of ​​the negative electrode active material area exceeds the first end, and the negative electrode ear is connected to the first area, the first area corresponding side is the ear side of the negative electrode active material area, the second area corresponding side is the non-ear side of the negative electrode active material area, the width E of the first area and the width C of the second area satisfy E>C, that is, the width of the part of the ear side of the negative electrode active material area that exceeds the ear side of the positive electrode active material area is greater than the width of the negative electrode active material area The width of the portion of the non-tab side of the positive electrode active material region that exceeds the non-tab side of the positive electrode active material region can be adjusted to adjust the position of the electrode assembly within the battery cell housing so that along the width direction of the positive electrode sheet, the distance between the first end and the wall of the housing is greater than the distance between the second end and the wall of the housing. This allows the housing to reserve more space for the electrolyte on the tab side of the negative electrode active material region and the tab side of the positive electrode active material region without increasing the volume of the housing, so that the positive and negative electrode sheets can be fully infiltrated, thereby providing the battery cell with better cycle performance and a higher volumetric energy density. Due to the large distance between the first end and the wall of the housing, when the electrode assembly is inserted into the housing, the safety issue of the tab being inserted into the electrode sheet due to bending of the tab can be reduced.

[0062] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as electric two-wheeled vehicles, power tools, drones, and energy storage devices. Battery cells meeting the operating conditions of this application can also be used as power supply systems for electrical devices, thereby improving the safety performance of the battery cells and the electrical safety of the electrical devices.

[0063] The present invention provides an electrical device that uses a battery cell as a power source. The electrical device may include, but is not limited to, electronic devices, power tools, electric vehicles, drones, and energy storage devices. Electronic devices may include mobile phones, tablets, and laptops, power tools may include electric drills and electric saws, and electric vehicles may include electric cars, electric motorcycles, and electric bicycles.

[0064] As shown in Figures 1 to 3, the battery cell 100 includes an electrode assembly 10, which includes a positive electrode sheet 11, a negative electrode sheet 12, a positive electrode ear 13 and a negative electrode ear 14. The positive electrode ear 13 is electrically connected to the positive electrode sheet 11, and the negative electrode ear 14 is electrically connected to the negative electrode sheet 12. The positive electrode sheet 11 includes a positive electrode active material area 111, and the negative electrode sheet 12 includes a negative electrode active material area 121; along the width direction X1 of the positive electrode sheet, the positive electrode active material area 111 has a first end 1111 and a second end 1112 relative to each other, and the positive electrode ear 13 protrudes from the first end 1111; along the width direction X2 of the negative electrode sheet, the negative electrode active material area 121 has a first area 1211 exceeding the first end 1111 and a second area 1212 exceeding the second end 1112, and the negative electrode ear 14 is connected to the first area 1211, the width of the first area 1211 is E, the width of the second area 1212 is C, and E>C.

[0065] The electrode assembly 10 may be a laminated structure or a wound structure. In embodiments where the electrode assembly 10 is a laminated structure, the positive electrode sheet 11, the separator 15, and the negative electrode sheet 12 are stacked one or more times in a certain order, and the positive electrode tab 13 electrically connected to the positive electrode sheet 11 and the negative electrode tab 14 electrically connected to the negative electrode sheet 12 extend along the same side of the electrode assembly 10.

[0066] In an embodiment in which the electrode assembly 10 has a wound structure, the positive electrode sheet 11, the separator 15 and the negative electrode sheet 12 are stacked in a certain order and then wound to form a wound structure. The positive electrode tab 13 electrically connected to the positive electrode sheet 11 and the negative electrode tab 14 electrically connected to the negative electrode sheet 12 extend along the same side of the electrode assembly 10.

[0067] The positive active material region 111 of the positive electrode sheet 11 is a region having a positive active material layer 113. The first end 1111 and the second end 1112 of the positive active material layer 113 are the two end surfaces of the positive active material region 111 that are flush with the edges of the positive active material layer 113 along the width direction X1 of the positive electrode sheet.

[0068] The positive electrode sheet 11 includes a positive electrode current collector 112 and a positive electrode active material layer 113. In some embodiments, both sides of the positive electrode current collector 112 in the thickness direction are fully coated with the positive electrode active material layer 113, and the edges of the positive electrode current collector 112 are flush with the edges of the positive electrode active material layer 113. The positive electrode tab 13 and the positive electrode sheet 11 are provided separately, and the positive electrode tab 13 and the positive electrode sheet 11 can be electrically connected by conductive adhesive bonding, welding connection, riveting connection, etc. In the embodiment where the positive electrode tab 13 and the positive electrode sheet 11 are provided separately, as shown in Figures 6 and 7, the positive electrode tab 13 can be connected to the first end 1111 of the positive electrode active material region 111. When observed along the thickness direction Z1 of the positive electrode sheet, the positive electrode tab 13 and the positive electrode active material region 111 have no overlapping portion. Avoiding the overlap between the positive electrode tab 13 and the positive electrode active material region 111 increases the size of the electrode assembly 10, which is beneficial to improving the volume energy density of the battery cell 100.

[0069] In an embodiment where the positive electrode tab 13 and the positive electrode sheet 11 are separately provided, as shown in Figures 8-11 , when viewed along the thickness direction Z1 of the positive electrode sheet, the positive electrode tab 13 and the positive active material region 111 have an overlapping portion, thereby achieving electrical connection between the positive electrode tab 13 and the positive electrode sheet 11. Furthermore, the positive electrode tab 13 protrudes beyond the first end 1111 of the positive active material region 111 along the width direction X1 of the positive electrode sheet, facilitating connection between the separately provided positive electrode tab 13 and the positive electrode sheet 11. Specifically, as shown in Figures 8 and 9 , when viewed along the length direction Y1 of the positive electrode sheet, the positive electrode tab 13 is provided on the side of the positive electrode active material layer 113 facing away from the positive electrode current collector 112. A portion of the positive electrode active material layer 113 is laminated between the positive electrode tab 13 and the positive electrode current collector 112. The positive electrode tab 13 and the positive electrode sheet 11 are riveted together to achieve electrical connection between the positive electrode tab 13 and the positive electrode sheet 11. There are many ways to rivet the positive electrode ear 13 and the positive electrode sheet 11. For example, in the thickness direction Z1 of the positive electrode sheet, the positive electrode ear 13 is stacked and arranged on the side of the positive electrode active material layer 113 away from the positive electrode current collector 112. A punch is used to sequentially penetrate the positive electrode ear 13, the positive electrode active material layer 113, the positive electrode current collector 112 and another positive electrode active material layer 113 from the side of the positive electrode ear 13 away from the positive electrode sheet 11. In the process of the punch penetrating the positive electrode ear 13 and the positive electrode sheet 11, due to the ductility of the material of the positive electrode ear 13, a first rivet portion 131 is formed on the positive electrode ear 13. The first rivet portion 131 will follow the punch to sequentially penetrate the positive electrode active material layer 113, the positive electrode current collector 112 and another positive electrode active material layer 113 and protrude from the surface of the positive electrode sheet 11 on the side away from the positive electrode ear 13. The portion of the first rivet portion 131 protruding from the surface of the positive electrode sheet 11 on the side away from the positive electrode ear 13 is flattened so that one end of the first rivet portion 131 forms a first limiting portion 132 that presses against the surface of the positive electrode sheet 11 on the side away from the positive electrode ear 13, thereby achieving riveting of the positive electrode ear 13 and the positive electrode sheet 11.

[0070] In other embodiments, the positive electrode tab 13 and the positive electrode sheet 11 may also be riveted together by a first rivet. The first rivet passes through the positive electrode tab 13 and the positive electrode sheet 11, and both ends of the first rivet are flattened to form a first retaining structure that presses against the surface of the positive electrode tab 13 facing away from the positive electrode sheet 11, and a second retaining structure that presses against the surface of the positive electrode sheet 11 facing away from the positive electrode tab 13.

[0071] As shown in Figures 10 and 11, a first mounting groove 1231 can also be provided on the positive active material layer 113 on one side of the positive electrode current collector 112. The depth of the first mounting groove 1231 is the same as the thickness of the positive electrode active material layer 113. The first mounting groove 1231 is used to accommodate a portion of the positive electrode tab 13. The positive electrode tab 13 protrudes from the first mounting groove 1231 along the width direction X1 of the positive electrode sheet at the first end 1111. The positive electrode tab 13 can be electrically connected to the positive electrode current collector 112 within the first mounting groove 1231. The electrical connection between the positive electrode tab 13 and the positive electrode current collector 112 can be achieved by connecting with conductive adhesive, welding, or other methods.

[0072] As shown in Figures 12 to 15, in some embodiments, along the width direction of the positive electrode current collector 112, the positive electrode current collector 112 has a coated area 1121 coated with a positive electrode active material layer 113 and an uncoated area 1122 not coated with the positive electrode active material layer 113. The coated area 1121 and the positive electrode active material layer 113 together form the positive electrode active material region 111 of the positive electrode sheet 11, and at least a portion of the uncoated area 1122 can form the positive electrode tab 13. For example, the uncoated area 1122 can be die-cut to form a plurality of spaced positive electrode tabs 13, and a portion of the uncoated area 1122 forms the positive electrode tab 13.

[0073] As shown in Figures 12 and 13, during the die-cutting process, in the width direction of the positive electrode current collector 112, the die-cutting position can be flush with the edge of the positive electrode active material layer 113 along the width direction of the positive electrode current collector 112, and the root of the positive electrode ear 13 is located at the edge of the coating area 1121.

[0074] As shown in Figures 14 and 15, during the die-cutting process, in the width direction of the positive current collector 112, the die-cutting position may not be flush with the edge of the positive active material layer 113 along the width direction of the positive current collector 112, thereby reducing the risk of damaging the positive active material layer 113 during the die-cutting process. The positive electrode sheet 11 includes a positive active material area 111 and a partially uncoated area 1121 of the positive current collector 112. Along the width direction of the positive current collector 112, there is a distance between the root of the positive electrode tab 13 and the edge of the coated area 1121. It should be noted that the width direction of the positive current collector 112 is parallel to the width direction X1 of the positive electrode sheet.

[0075] As shown in FIG. 16 , in some embodiments, the entire non-coated region 1122 of the positive electrode current collector 112 can form a positive electrode tab 13 , thereby forming a full-tab battery cell.

[0076] In the embodiment where at least a portion of the non-coated area 1122 of the positive electrode current collector 112 forms the positive electrode tab 13 , it can be understood that the positive electrode tab 13 and the positive electrode sheet 11 are integrally formed.

[0077] It should be noted that, in the longitudinal direction Y1 of the positive electrode sheet, the positive electrode active material layer 113 may be coated on the positive electrode current collector 112 in a continuous coating manner or in an intermittent coating manner.

[0078] Taking the lithium-ion battery cell 100 as an example, the material of the positive current collector 112 can be aluminum, and the positive active material layer 113 can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. In embodiments where the positive electrode sheet 11 and the positive tab 13 are separately provided and then electrically connected, the material of the positive tab 13 can be the same as or different from the material of the positive current collector.

[0079] The negative electrode active material region 121 of the negative electrode sheet 12 is the region having the negative electrode active material layer 123. The negative electrode sheet 12 includes a negative electrode current collector 122 and a negative electrode active material layer 123. The diagram illustrating the connection and relative positional relationship between the negative electrode tab 14 and the negative electrode sheet 12 can refer to the diagram illustrating the connection and relative positional relationship between the positive electrode tab 11 and the positive electrode tab 13.

[0080] In some embodiments, both sides of the negative electrode current collector 122 in the thickness direction are fully coated with the negative electrode active material layer 123, and the edge of the negative electrode current collector 122 is flush with the edge of the negative electrode active material layer 123. The negative electrode tab 14 and the negative electrode sheet 12 are provided separately, and the negative electrode tab 14 and the negative electrode sheet 12 can be electrically connected by conductive adhesive bonding, welding connection, riveting connection, etc.

[0081] In the embodiment in which the negative electrode ear 14 and the negative electrode sheet 12 are separately arranged, the negative electrode ear 14 can be connected to the end of the first region 1211 of the negative electrode active material region 121 away from the second region 1212. When observed along the thickness direction Z2 of the negative electrode sheet, there is no overlapping part between the negative electrode ear 14 and the negative electrode active material region 121, thereby avoiding the increase in the size of the electrode assembly 10 caused by the overlapping ears between the negative electrode ear 14 and the negative electrode active material region 121, which is beneficial to improving the volume energy density of the battery cell 100.

[0082] In the embodiment where the negative electrode tab 14 and the negative electrode sheet 12 are separately provided, the negative electrode tab 14 overlaps with the first region 1211 as viewed along the thickness direction Z2 of the negative electrode sheet, thereby achieving electrical connection between the negative electrode tab 14 and the negative electrode sheet 12. Furthermore, the negative electrode tab 14 protrudes beyond the end of the first region 1211 of the negative active material region 121 facing away from the second region 1212 along the width direction X2 of the negative electrode sheet, facilitating connection between the separately provided negative electrode tab 14 and the negative electrode sheet 12. Furthermore, as viewed along the length direction Y2 of the negative electrode sheet, the negative electrode tab 14 is provided on the side of the negative active material layer 123 facing away from the negative electrode current collector 122. A portion of the negative active material layer 123 is laminated between the negative electrode tab 14 and the negative electrode current collector 122. The negative electrode tab 14 and the negative electrode sheet 12 are riveted together to achieve electrical connection between the negative electrode tab 14 and the negative electrode sheet 12. There are many ways to rivet the negative electrode ear 14 and the negative electrode sheet 12. For example, in the thickness direction Z2 of the negative electrode sheet, the negative electrode ear 14 is stacked and arranged on the side of the negative electrode active material layer 123 away from the negative electrode current collector 122. The punch needle is used to pass through the negative electrode ear 14, the negative electrode active material layer 123, the negative electrode current collector 122 and another negative electrode active material layer 123 in sequence from the side of the negative electrode ear 14 away from the negative electrode sheet 12. In the process of the punch needle passing through the negative electrode ear 14 and the negative electrode sheet 12, due to the ductility of the material of the negative electrode ear 14, a second rivet portion is formed on a part of the negative electrode ear 14. The second rivet portion will follow the punch needle to pass through the negative electrode active material layer 123, the negative electrode current collector 122 and another negative electrode active material layer 123 in sequence and protrude from the surface of the negative electrode sheet 12 on the side away from the negative electrode ear 14. The portion of the second rivet portion protruding from the surface of the negative electrode sheet 12 on the side facing away from the negative electrode ear 14 is flattened so that one end of the second rivet portion forms a second limiting portion that presses against the surface of the negative electrode sheet 12 on the side facing away from the positive electrode ear 13, thereby achieving riveting of the negative electrode ear 14 and the negative electrode sheet 12.

[0083] In other embodiments, the negative electrode tab 14 and the negative electrode sheet 12 may also be riveted together by a second rivet. The second rivet passes through the negative electrode tab 14 and the negative electrode sheet 12, and both ends of the second rivet are flattened to form a third retaining structure that presses against the surface of the negative electrode tab 14 facing away from the negative electrode sheet 12, and a fourth retaining structure that presses against the surface of the negative electrode sheet 12 facing away from the negative electrode tab 14.

[0084] In other embodiments, a second mounting groove may be provided on the negative active material layer 123 on one side of the negative electrode current collector 122. The depth of the second mounting groove is equal to the thickness of the negative electrode active material layer 123. The second mounting groove is used to accommodate a portion of the negative electrode tab 14. The negative electrode tab 14 protrudes from the second mounting groove along the width direction X2 of the negative electrode sheet, extending from the first region 1211 away from the second region 1212. Within the second mounting groove, the negative electrode tab 14 can be electrically connected to the negative electrode current collector 122. The electrical connection between the negative electrode tab 14 and the negative electrode current collector 122 can be achieved by means of conductive adhesive, welding, or other methods.

[0085] In some embodiments, along the width of the negative electrode current collector 122, the negative electrode current collector 122 has a coated region coated with the negative electrode active material layer 123 and an uncoated region not coated with the negative electrode active material layer 123. The coated region 122 and the negative electrode active material layer 123 together form the negative electrode active material region 121 of the negative electrode sheet 12. At least a portion of the uncoated region 122 can form the negative electrode tab 14. For example, the uncoated region 1122 can be die-cut to form a plurality of spaced negative electrode tabs 14 in the uncoated region of the negative electrode current collector 122. A portion of the uncoated region 122 forms the negative electrode tab 14. During the die-cutting process, the die-cutting position can be flush with the edge of the negative electrode active material layer 123 along the width of the negative electrode current collector 122. Thus, the root of the negative electrode tab 14 is located at the edge of the coated region of the negative electrode current collector 122. During the die-cutting process, the die-cutting position in the width direction of the negative electrode current collector 122 does not need to be flush with the edge of the negative electrode active material layer 123 along the width direction of the negative electrode current collector 122, reducing the risk of damaging the negative electrode active material layer 123 during the die-cutting process. The negative electrode sheet 12 includes a negative electrode active material area 121 and a partially uncoated area of ​​the negative electrode current collector 122. Along the width direction of the negative electrode current collector 122, there is a distance between the root of the negative electrode tab 14 and the edge of the coated area of ​​the negative electrode current collector 122. It should be noted that the width direction of the negative electrode current collector 122 is parallel to the width direction X2 of the negative electrode sheet. The width direction X2 of the negative electrode sheet is parallel to the width direction X1 of the positive electrode sheet.

[0086] It should be noted that, in the longitudinal direction Y2 of the negative electrode sheet, the negative electrode active material layer 123 may be coated on the negative electrode current collector 122 in a continuous coating manner or may be coated on the negative electrode current collector 123 in an intermittent coating manner.

[0087] When the positive electrode sheet 11 is in the unfolded state, the width direction X1, the length direction Y1, and the thickness direction Z1 of the positive electrode sheet are perpendicular to each other. When the negative electrode sheet 12 is in the unfolded state, the width direction X2, the length direction Y2, and the thickness direction Z2 of the negative electrode sheet are perpendicular to each other.

[0088] In an embodiment in which the electrode assembly 10 is a wound structure, the width direction X1 of the positive electrode sheet is parallel to the extension direction of the winding axis of the electrode assembly 10 , and the width direction X2 of the negative electrode sheet is parallel to the extension direction of the winding axis of the electrode assembly 10 .

[0089] In some embodiments, the entire non-coated area of ​​the negative electrode current collector 122 can form the negative electrode tab 14 , and a full-tab battery cell can be formed.

[0090] In the embodiment where at least a portion of the non-coated area of ​​the negative electrode current collector 122 forms the negative electrode tab 14 , it can be understood that the negative electrode tab 14 and the negative electrode sheet 12 are integrally formed.

[0091] The negative electrode current collector 122 may be made of copper, and the negative electrode active material may be carbon or silicon.

[0092] The first region 1211 of the negative active material region 121 is a portion extending beyond the first end 1111 along its width direction. The second region 121 is a portion extending beyond the second end 1112 along its width direction.

[0093] E is the dimension of the first region 1211 along the span direction of the negative electrode sheet 12. C is the dimension of the second region 1212 along the span direction of the negative electrode sheet 12. E>C can be understood as E>(H2-H1) / 2, C<(H2-H1) / 2, that is, E>(H2-H1) / 2>C. Here, H1 is the width of the positive electrode active material region 111 along the width direction X1 of the positive electrode sheet, and H2 is the width of the negative electrode active material region 121 along the width direction X2 of the negative electrode sheet.

[0094] As shown in Figures 1-3, the battery cell 100 also includes a housing 30, within which the electrode assembly 10 is housed. The housing 30 forms a storage space. The storage space can be used to accommodate the electrode assembly 10, electrolyte, and the like. The housing 30 can be made of materials including, but not limited to, steel, aluminum, and copper. The housing 30 can be a hard shell, such as a steel shell, an aluminum shell, or a hard plastic shell. The housing 30 can also be a soft shell, such as an aluminum-plastic film, thereby forming a pouch cell 100.

[0095] As shown in Figures 1 and 2, the positive tab 13 connected to the positive electrode sheet 11 can be stacked in the outer shell 30 and bent before being electrically connected to the first electrode lead 40. Part of the first electrode lead 40 is located in the outer shell 30, and another part of the first electrode lead 40 extends out of the outer shell 30 to form the positive terminal of the battery cell 100. The first electrode lead 40 can be welded to the multiple stacked positive tabs 13.

[0096] As shown in Figures 1 and 3, the negative electrode tab 14 connected to the negative electrode sheet 12 can be stacked in the outer shell 30 and bent before being electrically connected to the second electrode lead 50. Part of the second electrode lead 50 is located in the outer shell 30, and another part of the second electrode lead 50 extends out of the outer shell 30 to form the negative terminal of the battery cell 100. The second electrode lead 50 can be welded to the multiple stacked negative electrode tabs 14.

[0097] The positive electrode tab 13 protrudes from the first end 1111 of the positive electrode active material region 111, the first end 1111 corresponding to the side of the tab of the positive electrode active material region 111, and the second end 1112 corresponding to the side of the non-tab side of the positive electrode active material region 111. The first region 1211 of the negative electrode active material region 121 exceeds the first end 1111, and the negative electrode tab 14 is connected to the first region 1211, the first region 1211 corresponding to the side of the tab of the negative electrode active material region 121, and the second region 1212 corresponding to the non-tab side of the negative electrode active material region 121. The width E of the first region 1211 and the width C of the second region 1212 satisfy E>C, that is, the width of the portion of the tab side of the negative electrode active material region 121 that exceeds the tab side of the positive electrode active material region 111 is greater than or equal to C. The width is greater than the width of the portion of the non-tab side of the negative active material area 121 that exceeds the non-tab side of the positive active material area 111, so that the position of the electrode assembly 10 in the shell 30 of the battery cell 100 can be adjusted so that along the width direction X1 of the positive electrode sheet, the distance between the first end 1111 and the wall of the shell 30 is greater than the distance between the second end 1112 and the wall of the shell 30, thereby achieving that without increasing the volume of the shell 30, the shell 30 reserves more space for the electrolyte on the tab side of the negative active material area 121 and the tab side of the positive active material area 111, so that the positive electrode sheet 11 and the negative electrode sheet 12 can be fully infiltrated, so that the battery cell 100 has better cycle performance and the battery cell 100 has a higher volume energy density.

[0098] In some embodiments, 1.05≤E / C≤10.

[0099] Illustratively, E / C may be 1.05, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, etc.

[0100] If E / C<1.05, the width of the portion of the tab side of the negative active material region 121 that exceeds the tab side of the positive active material region 111 is smaller than the width of the portion of the non-tab side of the negative active material region 121 that exceeds the non-tab side of the positive active material region 111, then the distance between the first end 1111 and the wall of the shell 30 is smaller, and the space reserved for the electrolyte on the tab side of the negative active material region 121 and the tab side of the positive active material region 111 of the shell 30 is smaller, and the risk of the positive electrode sheet 11 and the negative electrode sheet 12 not being fully infiltrated is greater. If E / C>10, the width of the portion of the tab side of the negative active material region 121 that exceeds the tab side of the positive active material region 111 is much greater than the width of the portion of the non-tab side of the negative active material region 121 that exceeds the positive active material region The width of the part of the non-pole ear side of the material area 111, the distance between the first end 1111 and the wall of the shell 30 is too large, and the distance between the second end 1112 and the wall of the shell 30 is too small. The shell 30 reserves a large space for the electrolyte on the pole ear side of the negative active material area 121 and the pole ear side of the positive active material area 111. The contained electrolyte exceeds the requirement for sufficient infiltration of the positive electrode sheet 11 and the negative electrode sheet 12, which may result in waste of material and space. The space reserved for the electrolyte on the non-pole ear side of the negative active material area 121 and the non-pole ear side of the positive active material area 111 is small, which may result in insufficient infiltration of the positive electrode sheet 11 and the negative electrode sheet 12 on the non-pole ear side of the negative active material area 121 and the non-pole ear side of the positive active material area 111. Therefore, 1.05≤E / C≤10, the space reserved for the electrolyte on the tab side of the negative active material area 121 and the tab side of the positive active material area 111 of the shell 30, and the space reserved for the electrolyte on the non-tab side of the negative active material area 121 and the non-tab side of the positive active material area 111 of the shell 30 are both relatively reasonable, so that the positive electrode sheet 11 and the negative electrode sheet 12 can be fully infiltrated, so that the battery cell 100 has better cycle performance, and can also reduce material waste, save costs, and reduce the waste of internal space of the shell 30. The space inside the shell 30 is fully utilized to improve the volume energy density of the battery cell 100.

[0101] In some embodiments, 1.1≤E / C≤4.

[0102] For example, E / C can be 1.1, 1.5,

[0103] E / C can be 1.1, 1.3, 2.1, 2.3, 2.7, 2.9, 3.1, 3.3, 3.7, 3.9, 4, etc.

[0104] 1.1≤E / C≤4, so that the battery cell 100 has better cycle performance, can further reduce material waste, further save costs, and further reduce the waste of internal space of the shell 30. The space inside the shell 30 is fully utilized to improve the volume energy density of the battery cell 100.

[0105] As shown in FIG. 17 and FIG. 18 , in some embodiments, the battery cell 100 further includes an insulating member 20 , and at least a portion of the insulating member 20 is located between the first region 1211 and the positive electrode tab 13 .

[0106] The insulating member 20 is used to separate the first region 1211 from the positive tab 13. The insulating member 20 may also be referred to as AT9. The insulating member 20 may be made of adhesive tape, ceramic, or other materials. The insulating member 20 may be disposed on the positive tab 13 so that it covers the surface of the positive tab 13. For example, the insulating member 20 may be bonded to the thickness surface of the positive tab 13 or coated on the thickness surface of the positive tab 13.

[0107] Along the width direction X2 of the negative electrode sheet, the insulating member 20 can extend beyond the first region 1211 and away from one end of the second region 1212 to increase the coverage area of ​​the insulating member 20 and further reduce the risk of burrs on the positive electrode tab 13, the negative electrode tab 14 and the first region 1211 puncturing the isolation membrane 15.

[0108] Along the width direction X2 of the negative electrode sheet, the end of the insulating member 20 facing away from the positive electrode active material region 111 can be flush with the end of the first region 1211 facing away from the second region 1212. It should be noted that the "flush" described in the embodiments of the present application may not be absolutely flush, and a certain range of error may be allowed, for example, the error range may be 0 mm to 0.5 mm.

[0109] At least a portion of the insulating member 20 is located between the first region 1211 and the positive electrode tab 13 , which can separate the first region 1211 and the positive electrode tab 13 , reducing the risk of burrs on the positive electrode tab 13 piercing the isolation membrane 15 and causing the positive electrode tab 13 and the first region 1211 to contact and short-circuit, thereby improving the safety performance of the battery cell 100 .

[0110] As shown in FIG. 17 and FIG. 18 , in some embodiments, along the width direction X2 of the negative electrode sheet, the first region 1211 has a third end 12111 away from the second region 1212 , and the insulating member 20 extends beyond the third end 12111 in a direction away from the positive active material region 111 .

[0111] In the width direction X2 of the negative electrode sheet, the insulating part 20 extends beyond the first region 1211 and away from the third end 12111 of the second region 1212 in the direction away from the positive active material area 111. The insulating part 20 can not only separate the first region 1211 and the positive electrode ear 13, but also separate the negative electrode ear 14 and the positive electrode ear 13, which can reduce the risk of burrs of the positive electrode ear 13 and the burrs of the negative electrode ear 14 piercing the isolation membrane 15, causing the positive electrode ear 13 and the negative electrode ear 14 to contact and short-circuit, thereby further improving the safety performance of the battery cell 100.

[0112] In the embodiment in which the insulating member 20 extends beyond the first region 1211 and away from the third end 12111 of the second region 1212 in the width direction X2 of the negative electrode sheet in a direction away from the positive electrode active material area 111, the insulating member 20 has a third region 21 extending beyond the third end 12111 along the width direction X2 of the negative electrode sheet, and the width of the third region 21 is F, 0<(E+C) / 2-F≤5mm.

[0113] The width F of the third region 21 is the dimension of the third region 21 in the width direction X2 of the negative electrode sheet.

[0114] (E+C) / 2-F may be equivalent to (H2-H1) / 2-F. For example, (E+C) / 2-F may be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc.

[0115] If (E+C) / 2-F>5mm, the insulating member 20 is too wide and occupies a large space, which will occupy more space on the tab side to accommodate the electrolyte. There is a greater risk that the positive electrode sheet 11 and the negative electrode sheet 12 will not be fully wetted, which is not conducive to the battery cell 100 having a high volumetric energy density. Therefore, 0<(E+C) / 2-F≤5mm can not only effectively separate the first region 1211 and the positive tab 13, reducing the risk of the positive tab 13 puncturing the separator 15 and causing a short circuit in the battery cell 100, but also minimize the space on the tab side to accommodate the electrolyte, allowing the positive electrode sheet 11 and the negative electrode sheet 12 to be better wetted by the electrolyte, improving the cycle performance of the battery cell 100, and also contributing to the battery cell 100 having a high volumetric energy density.

[0116] In some embodiments, 0.1 mm ≤ (E+C) / 2-F ≤ 1 mm.

[0117] That is, 0.1 mm ≤ (H2 - H1) / 2 - F ≤ 1 mm. (E + C) / 2 - F can be 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, etc.

[0118] If (E+C) / 2-F<0.1mm, the insulating member 20 cannot effectively separate the first region 1211 and the positive electrode ear 13. 0.1mm≤(E+C) / 2-F≤1mm can not only enable the insulating member 20 to effectively separate the first region 1211 and the positive electrode ear 13, reducing the risk of burrs of the positive electrode ear 13 piercing the isolation membrane 15 and causing a short circuit in the battery cell 100, but also enable the battery cell 100 to have a better volume energy density.

[0119] As shown in FIG. 17 and FIG. 18 , in some embodiments, one end of the insulating member 20 contacts the first end 1111 .

[0120] An end of the insulating member 20 closest to the positive active material region 111 contacts the first end 1111 .

[0121] The first end 1111 contacts one end of the insulating member 20. ...

[0122] One end of the insulating member 20 contacts the first end 1111 , which can increase the coverage area of ​​the insulating member 20 , better separate the first region 1211 and the positive electrode tab 13 , further reduce the risk of short circuit of the battery cell 100 , and improve the safety performance of the battery cell 100 .

[0123] As shown in Figure 19, in other embodiments, along the width direction X1 of the positive electrode sheet, the end of the insulating member 20 closest to the positive electrode active material area 111 can form a gap P with the first end 1111. In this way, when the insulating member 20 is set, the end of the insulating member 20 closest to the positive electrode active material area 111 can have a certain distance from the first end 1111, which can reduce the risk of damaging the positive electrode active material layer 113.

[0124] Of course, in other embodiments, the battery cell 100 may not be provided with an insulating part 20 (shown in Figures 4 and 5) for separating the first area 1211 and the positive electrode ear 13, which can reduce the occupation of the internal space of the shell 30 and reserve more space for accommodating the electrolyte, which is conducive to sufficient wetting of the positive electrode sheet 11 and the negative electrode sheet 12, so that the battery cell 100 has better cycle performance.

[0125] As shown in Figures 2 and 3, in some embodiments, the housing 30 has a first wall 31 and a second wall 32 arranged opposite to each other, the first end 1111 is arranged facing the first wall 31, and the second end 1112 is arranged facing the second wall 32; the distance between the first area 1211 and the first wall 31 is K1, and the distance between the second area 1212 and the second wall 32 is K2, K1>K2.

[0126] The first wall 31 and the second wall 32 are part of the wall portion of the housing 30. The first wall 31 and the second wall 32 are arranged opposite each other along the width direction X1 of the positive electrode sheet. The spacing K1 between the first region 1211 and the first wall 31 is the distance between the third end 12111 of the first region 1211, facing away from the second region 1212, and the first wall 31, along the width direction X2 of the negative electrode sheet. The spacing K2 between the second region 1212 and the second wall 32 is the distance between the fifth end of the second region 1212, facing away from the first region 1211, and the second wall 32, along the width direction X2 of the negative electrode sheet.

[0127] Since the corresponding side of the first end 1111 is the tab side of the positive active material area 111, the corresponding side of the second end 1112 is the non-tab side of the positive active material area 111, the corresponding side of the first region 1211 is the tab side of the negative active material area 121, and the corresponding side of the second region 1212 is the non-tab side of the negative active material area 121, K1 and K2 satisfy K1>K2, that is, the distance between the tab side of the negative active material area 121 and the wall of the shell 30 is greater than the distance between the non-tab side of the negative active material area 121 and the wall of the shell 30, the shell 30 reserves more space for the electrolyte on the tab side of the negative active material area 121, so that the positive electrode sheet 11 and the negative electrode sheet 12 can be fully infiltrated, so that the battery cell 100 has better cycle performance and the battery cell 100 has a higher volume energy density.

[0128] As shown in Figure 2, in an embodiment where the battery cell 100 includes an insulating member 20, at least a portion of the insulating member 20 is located between the first region 1211 and the positive electrode tab 13; the insulating member 20 has a fourth end facing the first wall 31, and the distance between the fourth end and the first wall 31 is K3, K3>K2.

[0129] The fourth end is the end of the insulating member 20 in the width direction X1 of the positive electrode sheet away from the positive active material layer 113. The distance K3 between the fourth end and the first wall 31 is the distance between the fourth end and the first wall 31 along the width direction X1 of the positive electrode sheet.

[0130] K3>K2, the shell 30 reserves more space for the electrolyte on the tab side of the positive active material area 111, so that the positive electrode sheet 11 and the negative electrode sheet 12 can be fully infiltrated, thereby making the battery cell 100 have better cycle performance.

[0131] As shown in Figures 5, 18, and 19, in some embodiments, the electrode assembly 10 further includes a separator 15, which is used to separate the positive electrode sheet 11 and the negative electrode sheet 12. Along the width direction X1 of the positive electrode sheet, the width of the separator 15 beyond the first end 1111 is L1, and the width of the separator 15 beyond the second end 1112 is L2. <L1-L2≤8mm。

[0132] The positive electrode sheet 11 and the negative electrode sheet 12 are provided with a separator 15 for insulating and separating the positive electrode sheet 11 and the negative electrode sheet 12 to reduce the risk of short circuit of the battery cell 100. The separator 15 can be made of PP (polypropylene) or PE (polyethylene).

[0133] Define the part of the separator 15 extending beyond the first end 1111 along the width direction X1 of the positive electrode sheet as the fourth region, and L1 is the dimension of the fourth region along the width direction X1 of the positive electrode sheet. Define the part of the separator 15 extending beyond the second end 1112 along the width direction X1 of the positive electrode sheet as the fifth region, and L2 is the dimension of the fifth region along the width direction X1 of the positive electrode sheet.

[0134] Exemplarily, L1 - L2 can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, etc.

[0135] 0 < L1 - L2, that is, L1 > Lz. Since the width E of the first region 1211 where the negative electrode active material region 121 extends beyond the first end 1111 and the width C of the second region 1212 where it extends beyond the second end 1112 satisfy E > C, thus L1 > L2, so that the width of the part of the separator 15 extending beyond the first end 1111 and the width of the part of the separator 15 extending beyond the second end 1112 respectively match the width of the first region 1211 and the width of the second region 1212, so that the separator 15 can better separate the positive electrode sheet 11 and the negative electrode sheet 12, and can better alleviate the problem of short circuit of the battery cell 100, thereby improving the safety performance of the battery cell 100.

[0136] If L1 - L2 > 8 mm, the dimension of the separator 15 in the width direction X1 of the positive electrode sheet is too large, occupying a relatively large space inside the outer shell 30, which is not conducive to the full wetting of the positive electrode sheet 11 and the negative electrode sheet 12 and the battery cell 100 having a high energy density. Therefore, L1 - L2 ≤ 8 mm, so that the separator 15 can effectively separate the positive electrode sheet 11 and the negative electrode sheet 12, reduce the risk of short circuit of the battery cell 100, and can also minimize the dimension of the separator 15 in the width direction X1 of the positive electrode sheet as much as possible, so that the separator 15 occupies as little space inside the outer shell 30 as possible, so that there is more space inside the outer shell 30 to accommodate the electrolyte, which is conducive to the full wetting of the positive electrode sheet 11 and the negative electrode sheet 12, improving the cycle performance of the battery cell 100, and conducive to the battery cell 100 having a high energy density.

[0137] In some embodiments, 1 mm ≤ L1 - L2 ≤ 3 mm.

[0138] For example, L1 - L2 can be 1 mm, 1.3 mm, 1.5 mm, 1.7 mm, 2.3 mm, 2.5 mm, 2.7 mm, 3 mm, etc.

[0139] 1mm≤L1-L2≤3mm, so that the isolation membrane 15 can more effectively separate the positive electrode sheet 11 and the negative electrode sheet 12, further reducing the risk of short circuit of the battery cell 100, and can also minimize the size of the isolation membrane 15 in the width direction X1 of the positive electrode sheet, so that the isolation membrane 15 occupies as little space as possible inside the shell 30, so that there is more space inside the shell 30 to accommodate the electrolyte, which is conducive to full infiltration of the positive electrode sheet 11 and the negative electrode sheet 12, so that the battery cell 100 has better cycle performance and is conducive to the battery cell 100 having a high energy density.

[0140] An embodiment of the present application further provides an electrical device, which includes any of the above-mentioned battery cells 100 .

[0141] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, wherein: include: An electrode assembly, comprising a positive electrode sheet, a negative electrode sheet, a positive electrode ear and a negative electrode ear, wherein the positive electrode ear is electrically connected to the positive electrode sheet, the negative electrode ear is electrically connected to the negative electrode sheet, the positive electrode sheet comprises a positive electrode active material region, and the negative electrode sheet comprises a negative electrode active material region; Along the width direction of the positive electrode sheet, the positive electrode active material region has a first end and a second end opposite to each other, and the positive electrode ear protrudes from the first end; Along the width direction of the negative electrode sheet, the negative electrode active material area has a first region beyond the first end and a second region beyond the second end, the negative electrode ear is connected to the first region, the width of the first region is E, the width of the second region is C, and E>C.

2. The battery cell according to claim 1, wherein: 1.05≤E / C≤10.

3. The battery cell according to claim 2, wherein: 1.1≤E / C≤4.

4. The battery cell according to claim 1, wherein: The battery cell further includes an insulating member, at least a portion of which is located between the first region and the positive electrode tab.

5. The battery cell according to claim 4, wherein: Along the width direction of the negative electrode sheet, the first region has a third end away from the second region, and the insulating member extends beyond the third end in a direction away from the positive electrode active material region.

6. The battery cell according to claim 5, wherein: Along the width direction of the negative electrode sheet, the insulating member has a third region beyond the third end, and the width of the third region is F, 0<(E+C) / 2-F≤5mm.

7. The battery cell according to claim 6, wherein: 0.1mm≤(E+C) / 2-F≤1mm.

8. The battery cell according to claim 4, wherein: One end of the insulating member contacts the first end.

9. The battery cell according to claim 1, wherein: The battery cell further includes a shell, the electrode assembly is accommodated in the shell, the shell has a first wall and a second wall arranged opposite to each other, the first end is arranged facing the first wall, and the second end is arranged facing the second wall; The distance between the first area and the first wall is K1, the distance between the second area and the second wall is K2, and K1>K2.

10. The battery cell according to claim 9, wherein: The battery core further includes an insulating member, at least a portion of which is located between the first region and the positive electrode tab; The insulating member has a fourth end facing the first wall, and a distance between the fourth end and the first wall is K3, where K3>K2.

11. The battery cell according to claim 1, wherein: The electrode assembly further includes a separator, which is used to separate the positive electrode sheet from the negative electrode sheet. Along the width direction of the positive electrode sheet, the width of the separator extending beyond the first end is L1, and the width of the separator extending beyond the second end is L2. <L1-L2≤8mm。 12. The battery cell according to claim 10, wherein: 1mm≤L1-L2≤3mm.

13. An electrical device, wherein: Comprising the battery cell according to any one of claims 1-12.

Images