Positive electrode sheet, battery cell, and battery

Abstract

The utility model relates to battery technology field discloses a kind of positive plate, battery cell and battery, positive plate includes positive plate ontology and flexible filling body, and positive plate ontology includes multiple bending sections and multiple straight sections that are alternatively connected along winding direction, and bending section is equipped with multiple interval distribution's accommodating hole;Flexible filling body is filled with flexible filling body in each accommodating hole, and flexible filling body is configured to produce elastic deformation when being pressed, to improve the condition of lithium precipitation on the surface of negative plate.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a positive electrode sheet, a battery cell, and a battery. Background Technology

[0002] Lithium-ion batteries have advantages such as high energy density, long cycle life and environmental friendliness, and are widely used in various fields.

[0003] Because the negative electrode undergoes significant volume changes during charge and discharge cycles, the contact between layers is very tight in the corner areas of the wound cell. The expansion and contraction of the negative electrode are more constrained. As the number of cycles increases, this constraint leads to the gradual accumulation of internal stress in the negative electrode, which in turn causes the coating of the negative electrode active material to crack or peel off from the copper foil substrate, resulting in lithium deposition on the surface of the negative electrode and affecting the capacity and safety performance of the cell. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a positive electrode sheet that can improve the situation of lithium deposition on the surface of the negative electrode sheet.

[0005] This utility model also proposes a battery cell having the above-mentioned positive electrode plate, and a battery having the battery cell.

[0006] According to a first aspect of the present invention, a positive electrode sheet includes a positive electrode sheet body and a flexible filler. The positive electrode sheet body includes a plurality of bent segments and a plurality of straight segments that are alternately connected along the winding direction. The bent segments are provided with a plurality of spaced-apart receiving holes. Each receiving hole of the flexible filler is filled with a flexible filler, and the flexible filler is configured to generate elastic deformation when compressed.

[0007] The positive electrode sheet according to the embodiments of this utility model has at least the following beneficial effects: By providing multiple spaced-apart receiving holes in the bending section, when the positive electrode sheet is applied to the battery cell, the receiving holes can provide expansion space for the expansion of the negative electrode sheet, so as to allow the negative electrode sheet in the corner area of ​​the battery cell to expand and contract, which helps to improve the situation of negative electrode coating peeling and cracking on the negative electrode sheet, thereby improving the situation of lithium plating on the surface of the negative electrode sheet. By filling each receiving hole with a flexible filler, the flexible filler can generate elastic deformation when compressed, so when the negative electrode sheet expands and squeezes the flexible filler, the flexible filler can provide expansion space for the negative electrode sheet through elastic deformation and can support the negative electrode sheet, which helps to improve the situation of bulging in the corner area of ​​the battery cell caused by excessive expansion of the negative electrode sheet.

[0008] According to some embodiments of the present invention, the filling volume of the flexible filler in the receiving hole is smaller than the volume of the receiving hole.

[0009] According to some embodiments of the present invention, the flexible filler includes a filling portion and an extension portion connected together. The filling portion fills the accommodating hole and is bonded to the hole wall of the accommodating hole, while the extension portion protrudes outside the accommodating hole and is bonded to the outer surface of the positive electrode body. The volume of the filling portion is smaller than the volume of the accommodating hole.

[0010] According to some embodiments of the present invention, the thickness of the epitaxial portion is ≥1μm and ≤5μm; and / or, the maximum distance between the epitaxial portion and the edge of the accommodating hole wall is ≥0.2mm and ≤1mm.

[0011] According to some embodiments of the present invention, the positive electrode body includes a first positive electrode coating, a substrate layer and a second positive electrode coating connected sequentially along the thickness direction; a receiving hole penetrates at least one of the first positive electrode coating and the second positive electrode coating and penetrates the substrate layer; a flexible filler connects the first positive electrode coating and the second positive electrode coating and is a flexible conductive filler.

[0012] According to some embodiments of the present invention, the flexible filler is a PEDOT / PSS flexible filler.

[0013] According to some embodiments of the present invention, the diameter of the receiving hole is ≥0.5mm and ≤1.5mm; and / or, the distance between two adjacent receiving holes is ≥0.5mm and ≤2.5mm; and / or, the positive electrode body has two opposite edges spaced apart along the width direction, both edges extending along the winding direction; the distance between the receiving hole closest to the edge and the edge is ≥1mm and ≤5mm.

[0014] According to some embodiments of the present invention, the positive electrode body has two opposite edges spaced apart along the width direction, both edges extending along the winding direction; a plurality of receiving holes are arranged in n columns along the winding direction, each column including a plurality of receiving holes arranged sequentially at intervals along the width direction; wherein, n is an integer ≥1; and / or, the bent section has a perforated area, the perforated area is spaced apart from the straight section, and the plurality of receiving holes are distributed in the perforated area; a center line is defined extending along the width direction and passing through the center of the bent section along the winding direction, the perforated area has two boundary lines located on opposite sides of the center line along the winding direction, and the distance between each boundary line and the center line along the winding direction is ≥3mm and ≤5mm.

[0015] The battery cell according to a second aspect embodiment of the present invention includes the positive electrode sheet in any of the above embodiments.

[0016] The battery according to a third aspect of the present invention includes the battery cell described in the above embodiments.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0019] Figure 1 This diagram shows a partial cross-sectional view of the battery cell provided in an embodiment of the present invention.

[0020] Figure 2 This diagram shows a partial structural schematic of the positive electrode body provided in an embodiment of the present invention;

[0021] Figure 3 A partial cross-sectional schematic diagram of the positive electrode sheet provided in an embodiment of the present invention is shown.

[0022] Figure label:

[0023] Cell 10; Positive electrode 100; Positive electrode body 110; Straight section 111; Bending section 113; Drilled area 1131; Accommodating hole 1137; First spacer area 1133; Second spacer area 1135; First positive electrode coating 115; Substrate layer 117; Second positive electrode coating 119; Flexible filler 130; Filling part 131; Extension part 133; Negative electrode 200; Separator 300; Corner area 400; Center line M; Boundary line P; Winding direction X; Width direction Y. Detailed Implementation

[0024] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0025] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0027] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0028] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0029] Please see Figure 1 This application provides a battery, which includes a cell 10. The battery can be a pouch battery or a steel-cased battery; the specific structure can be found in the prior art and will not be described in detail here.

[0030] In some embodiments, the battery cell 10 includes a positive electrode 100, a negative electrode 200, and a separator 300.

[0031] As an example, when the battery is a pouch battery, the cell 10 may include an encapsulation film and a cell body. The encapsulation film may cover the cell body. The cell body may be formed by stacking and winding a negative electrode 200, a separator 300 and a positive electrode 100. The separator 300 may separate the negative electrode 200 and the positive electrode 100 to avoid short circuits. The specific structure of the cell body may refer to the prior art and will not be described in detail here.

[0032] As another example, when the battery is a steel-cased battery, the cell 10 can be formed by stacking and winding the negative electrode 200, the separator 300 and the positive electrode 100, and can be directly installed in the casing of the steel-cased battery.

[0033] For ease of description, the following explanation will take a pouch battery as an example. Understandably, the cell 10 can have two opposite corner areas 400.

[0034] Please see Figures 1 to 3 In some embodiments, the positive electrode 100 includes a positive electrode body 110 and a flexible filler 130.

[0035] The positive electrode body 110 includes multiple bent segments 113 and multiple straight segments 111 that are alternately connected along the winding direction X, that is, two adjacent straight segments 111 are connected by a bent segment 113. It can be understood that when the positive electrode 100 is applied to the cell 10, the bent segment 113 is located in the corner region 400 of the cell 10.

[0036] The winding direction X can refer to the direction of the positive electrode 100 when it is wound into a cell. When the positive electrode 100 is in a flat and unfolded state, the winding direction X can be the length direction of the positive electrode 100.

[0037] The bending section 113 is provided with a plurality of spaced-apart receiving holes 1137. Thus, when the positive electrode 100 is applied to the cell 10, the receiving holes 1137 can provide expansion space for the expansion of the negative electrode 200, so that the negative electrode 200 in the corner region 400 can expand and contract, which helps to improve the situation of negative electrode coating peeling and cracking on the negative electrode 200, thereby improving the situation of lithium plating on the surface of the negative electrode 200.

[0038] Multiple receiving holes 1137 can refer to two or more receiving holes 1137.

[0039] The receiving hole 1137 can be set along the thickness direction of the bent section 113, that is, the axial direction of the receiving hole 1137 is approximately in the same direction as the thickness direction of the bent section 113. The receiving hole 1137 can be a through hole or a blind hole.

[0040] Each receiving hole 1137 is filled with a flexible filler 130. The flexible filler 130 is configured to undergo elastic deformation under pressure. The flexible filler 130 can provide expansion space for the negative electrode 200 through elastic deformation and can support the negative electrode 200, which helps to improve the situation where the corner area 400 of the cell 10 bulges due to excessive expansion of the negative electrode 200. When the negative electrode 200 shrinks, the flexible filler 130 can return to its original shape under the action of elastic restoring force, in preparation for the next expansion of the negative electrode 200. In addition, since the flexible filler 130 is filled in the receiving hole 1137, it can also reduce the impact on the thickness of the positive electrode body 110, thereby reducing the impact on the energy density of the cell 10.

[0041] Specifically, when the negative electrode 200 in the corner region 400 expands, it can compress the separator 300 to produce elastic deformation and enter the receiving hole 1137, and compress the flexible filler 130 through the separator 300. When the negative electrode 200 in the corner region 400 shrinks, the separator 300 can restore its original shape through its own elastic restoring force, the negative electrode 200 and the separator 300 disengage from the receiving hole 1137, and the flexible filler 130 restores its original shape through its own elastic restoring force.

[0042] In some embodiments, the positive electrode body 110 includes a first positive electrode coating 115, a substrate layer 117, and a second positive electrode coating 119 connected sequentially along the thickness direction. The specific preparation process can refer to the prior art and will not be described in detail here.

[0043] The accommodating hole 1137 can penetrate at least one of the first positive electrode coating 115 and the second positive electrode coating 119, and the accommodating hole 1137 can penetrate the substrate layer 117. The flexible filler 130 can connect the first positive electrode coating 115 and the second positive electrode coating 119, and the flexible filler 130 is a flexible conductive filler. Thus, the flexible filler 130 can provide a current transmission channel for the first positive electrode coating 115 and the second positive electrode coating 119, which helps to reduce the interface impedance of the corner region 400 of the battery, uniformize the lithium ion flow, reduce the local overpotential of the positive electrode, and thus suppress the formation of lithium dendrites.

[0044] As an example, the receiving hole 1137 may pass sequentially through the first positive electrode coating 115 and the substrate layer 117. The receiving hole 1137 may extend partially to the second positive electrode coating 119, or it may not extend to the second positive electrode coating 119. The flexible filler 130 may be connected between the cross-section formed by the receiving hole 1137 cutting through the first positive electrode coating 115 and the surface of the second positive electrode coating 119.

[0045] As another example, the receiving hole 1137 may pass sequentially through the second positive electrode coating 119 and the substrate layer 117. The receiving hole 1137 may extend partially to the first positive electrode coating 115, or it may not extend to the first positive electrode coating 115. The flexible filler 130 may be connected between the cross-section formed by the receiving hole 1137 cutting through the second positive electrode coating 119 and the surface of the first positive electrode coating 115.

[0046] As another example, the receiving hole 1137 can sequentially penetrate the first positive electrode coating 115, the substrate layer 117, and the second positive electrode coating 119. The flexible filler 130 can be connected to the cross-sections formed by the receiving hole 1137 cutting through the first positive electrode coating 115 and the second positive electrode coating 119, respectively.

[0047] The first positive electrode coating 115 can refer to the first positive electrode active material coating, and the second positive electrode coating 119 can refer to the second positive electrode active material coating.

[0048] In some embodiments, the flexible filler 130 can be a PEDOT / PSS flexible filler. The PEDOT / PSS flexible filler has good conductivity and excellent dispersion stability, which can further improve the current transmission efficiency between the first positive electrode coating 115 and the second positive electrode coating 119, uniform lithium ion flow, and further reduce the local overpotential of the positive electrode sheet 100, thereby better suppressing the formation of lithium dendrites.

[0049] Among them, the PEDOT / PSS flexible filler can be a polymer of PEDOT (poly(3,4-ethylenedioxythiophene)) doped with PSS (polystyrene sulfonic acid).

[0050] As an example, in the PEDOT / PSS flexible filler, the mass ratio of PEDOT to PSS can be ≥1 / 6 and ≤1 / 2.5, that is, 1 / 6 ≤ PEDOT mass / PSS mass ≤ 1 / 2.5. This ensures that the PEDOT / PSS flexible filler has both good conductivity and excellent dispersion stability. Preferably, the PEDOT mass / PSS mass = 1 / 4. During the synthesis of the PEDOT / PSS flexible filler, the particle size can be controlled by surfactants to ensure that the particle size of the PEDOT / PSS flexible filler is ≥50nm and ≤200nm.

[0051] In its microstructure, PEDOT exhibits a coexistence of ordered and disordered microregions. The PEDOT main chain tends to form locally ordered structural domains (i.e., ordered microregions) to provide electron transport channels, thus enhancing the conductivity of the PEDOT / PSS flexible filler. PSS, on the other hand, is distributed within the disordered microregions, forming ion transport channels. The sulfonic acid groups (-SO3) in PSS... - It can serve as a cation adsorption site, promoting the diffusion of lithium ions at the electrode interface and improving the stability of dispersed lithium ions in the PEDOT / PSS flexible filler.

[0052] In some embodiments, the flexible filler 130 may also be a PANI (polyaniline) / PSS flexible filler, a PPy (polypyrrole) / PSS flexible filler, a PPP (poly(p-phenylene)) / PSS flexible filler, or other flexible fillers 130.

[0053] In some embodiments, the filling volume of the flexible filler 130 in the receiving hole 1137 may be smaller than the volume of the receiving hole 1137. In this way, the receiving hole 1137 can provide deformation space for the elastic deformation of the flexible filler 130, which helps to improve the situation where the flexible filler 130 is deformed by pressure to the outside of the receiving hole 1137, and helps to further improve the situation of bulging in the corner area 400.

[0054] As an example, taking the receiving hole 1137 as a through hole, the receiving hole 1137 may have a first opening and a second opening spaced apart from each other. The first opening may be located on the side of the bent section 113 facing the inside of the battery cell 10, and the second opening may be located on the side of the bent section 113 facing the outside of the battery cell 10. The flexible filler 130 may be filled between the first opening and the second opening, and the flexible filler 130 may be spaced apart from at least one of the first opening and the second opening to provide deformation space for the elastic deformation of the flexible filler 130.

[0055] In some embodiments, the flexible filler 130 may include a filling portion 131 and an extension portion 133 connected to each other.

[0056] The filling portion 131 can fill the receiving hole 1137 and adhere to the hole wall of the receiving hole 1137, while the extension portion 133 is exposed outside the receiving hole 1137 and adheres to the outer surface of the positive electrode body 110. This can improve the connection strength between the flexible filler 130 and the positive electrode body 110, and help to improve the situation where the flexible filler 130 falls off the positive electrode body 110.

[0057] The volume of the filling part 131 can be smaller than the volume of the receiving hole 1137, so that the receiving hole 1137 can provide space for the elastic deformation of the filling part 131.

[0058] The filling portion 131 is bonded to the wall of the receiving hole 1137, which means that the filling portion 131 is bonded to the wall of the receiving hole 1137 by its own adhesiveness. The epitaxial portion 133 is bonded to the outer surface of the positive electrode body 110, which means that the epitaxial portion 133 is bonded to the outer surface of the positive electrode body 110 by its own adhesiveness.

[0059] It should be noted that when the receiving hole 1137 is a through hole, the flexible filler 130 may include two epitaxial portions 133, which may be respectively bonded to opposite sides of the positive electrode body 110 along the thickness direction. Understandably, when the receiving hole 1137 is a through hole, the flexible filler 130 may also include only one epitaxial portion 133, depending on the specific requirements.

[0060] As an example, after the bending section 113 of the positive electrode 100 is processed to accommodate the hole 1137, a liquid flexible filler 130 of a predetermined mass can be coated in the area of ​​the hole 1137. The liquid flexible filler 130 can adhere to the inner wall of the hole 1137 and the surface of the bending section 113. After the liquid flexible filler 130 dries, it forms a flexible filling portion 131 and an epitaxial portion 133. The predetermined mass can be flexibly set according to requirements to control the size of the filling portion 131 and the epitaxial portion 133.

[0061] In some embodiments, the volume of the filling portion 131 can be ≥ 50% of the volume of the receiving hole 1137 and ≤ 80% of the volume of the receiving hole 1137, thereby ensuring that space can be reserved in the receiving hole 1137 for elastic deformation of the filling portion 131, and the filling portion 131 can have a sufficiently large size to better support the expanded negative electrode 200.

[0062] In some embodiments, the area occupied by the filling portion 131 within the receiving hole 1137 can be ≥ 50% of the cross-sectional area of ​​the receiving hole 1137, which helps to increase the bonding area between the filling portion 131 and the hole wall of the receiving hole 1137, thereby improving the bonding strength.

[0063] In some embodiments, the thickness of the epitaxial portion 133 can be ≥1μm and ≤5μm (e.g., Figure 3 The L1 in the figure helps to reduce the impact of the epitaxial portion 133 on the thickness of the positive electrode 100 and can improve the bonding strength between the epitaxial portion 133 and the positive electrode body 110.

[0064] As an example, the thickness of the epitaxial portion 133 can be 1 μm, 1.9 μm, 2.5 μm, 3.5 μm, 5 μm, or other values ​​in [1 μm, 5 μm].

[0065] The shape of the extension portion 133 can be approximately circular or other shapes, and this application does not impose any restrictions.

[0066] In some embodiments, the maximum distance between the extension portion 133 and the wall of the receiving hole 1137 can be ≥0.2mm and ≤1mm (e.g., Figure 3 The L2 in the figure helps to ensure the bonding strength between the epitaxial portion 133 and the positive electrode body 110, and can also reduce the impact on the positive electrode coating (i.e., the first positive electrode coating 115 and / or the second positive electrode coating 119).

[0067] In some embodiments, the diameter of the receiving hole 1137 can be ≥0.5mm and ≤1.5mm, thereby ensuring that a flexible filler 130 of sufficient size can be accommodated in the receiving hole 1137 to provide a better lithium-ion transport channel for lithium ions, and also reduce the amount of positive electrode coating removed to ensure the energy storage performance of the positive electrode sheet 100.

[0068] As an example, the diameter of the receiving hole 1137 can be 0.5 mm, 0.8 mm, 0.85 mm, 1.3 mm, 1.5 mm or other values ​​in [0.5 mm, 1.5 mm].

[0069] In some embodiments, the distance between two adjacent receiving holes 1137 can be ≥0.5mm and ≤2.5mm (e.g., Figure 2The L3 in the middle helps to avoid the situation where two adjacent receiving holes 1137 are too close, which would cause the positive electrode body 110 to crack, and can also reduce the amount of positive electrode coating to be removed.

[0070] The distance between the two receiving holes 1137 can refer to the distance between the walls of two adjacent receiving holes 1137.

[0071] As an example, the distance between two adjacent receiving holes 1137 can be 0.5mm, 0.75mm, 1mm, 2.3mm, 2.5mm or other values ​​in [0.5mm, 2.5mm].

[0072] In some embodiments, the positive electrode body 110 may have two opposite edges spaced apart along the width direction Y, both edges extending along the winding direction X.

[0073] Among the multiple receiving holes 1137, the distance between the receiving hole 1137 closest to the edge and the edge is ≥1mm and ≤5mm (e.g., Figure 2 The L4 in the middle helps to prevent the receiving hole 1137 from damaging the integrity of the edge, thereby ensuring the structural strength of the positive electrode body 110.

[0074] As an example, the distance between the receiving hole 1137 closest to the edge and the edge can be 1 mm, 1.85 mm, 2.2 mm, 3.5 mm, 5 mm or other values ​​in [1 mm, 5 mm].

[0075] In some embodiments, the bent section 113 may have a perforated area 1131, which is spaced apart from the straight section 111, and a plurality of accommodating holes 1137 are distributed in the perforated area 1131.

[0076] As an example, the multiple straight segments 111 may include a first straight segment 111 and a second straight segment 111. Taking a bent segment 113 connected between the first straight segment 111 and the second straight segment 111 as an example, the bent segment 113 may include a first interval region 1133, a perforated region 1131, and a second interval region 1135 connected sequentially along the winding direction X. The first interval region 1133 may be connected between the first straight segment 111 and the perforated region 1131, and the second interval region 1135 may be connected between the perforated region 1131 and the second straight segment 111.

[0077] Define a centerline M extending along the width direction Y and passing through the center of the bend segment 113 along the winding direction X. The perforated area 1131 has two boundary lines P located on opposite sides of the centerline M along the winding direction X. The distance between each boundary line P and the centerline M along the winding direction X is ≥3mm and ≤5mm (e.g., ...). Figure 2In the case of L5), when the positive electrode 100 is applied to the cell 10, the perforated area 1131 can be located approximately at the center of the corner area 400. The negative electrode 200 is subjected to greater compression at the center of the corner area 400. By setting the perforated area 1131 at the center of the corner area 400, the accommodating hole 1137 can better provide expansion space for the expansion of the negative electrode 200, further improving the lithium plating situation of the negative electrode 200.

[0078] In some embodiments, a plurality of accommodating holes 1137 are distributed in n columns along the winding direction X, and each column includes a plurality of accommodating holes 1137 arranged sequentially along the width direction Y. Since the negative electrode 200 usually develops cracks and lithium deposition along the width direction Y, this embodiment can better improve the situation where the negative electrode 200 develops cracks and lithium deposition along the width direction Y by setting the plurality of accommodating holes 1137 to be arranged in columns along the width direction Y of the positive electrode body 110.

[0079] Where n can be an integer greater than or equal to 1, and the specific value can be set according to actual needs. As an example, n can be 1, 2, 3, 4, or other integers.

[0080] It should be noted that the number of accommodating holes 1137 in each column can be equal or unequal. Adjacent columns of accommodating holes 1137 can be symmetrically arranged or staggered along the width direction Y. The specific arrangement can be determined according to the requirements.

[0081] In some embodiments, the positive electrode body 110 may have a winding start end and a winding end. When the positive electrode body 110 is in an unfolded and laid-out state, the winding start end and the winding end are located at opposite ends of the positive electrode body 110 along the length direction.

[0082] Multiple reference lines are defined and spaced apart between the winding start end and the winding end, each extending along the width direction Y. The distance between the reference line closest to the winding start end and the winding start end is approximately the inner diameter of the cell 10. The inner diameter of the cell 10 is approximately the sum of the length of the innermost straight section 111 along the winding direction X and the diameter of the innermost bent section 113. Therefore, the reference line closest to the winding start end can be used as the center line M of the innermost bent section 113 after the positive electrode body 110 is wound. Understandably, the distance between each subsequent reference line and the starting end of winding is the distance between the previous reference line and the starting end of winding plus the thickness of the positive electrode body 110. Each reference line and each bending segment 113 can correspond one-to-one. Each reference line is approximately the center line M of the corresponding bending segment 113, so that the drilling area 1131 of each bending segment 113 can be easily determined, so that each bending segment 113 can be automatically drilled by an automated drilling device (such as a laser drilling device), which helps to improve the preparation speed of the positive electrode body 110.

[0083] In the positive electrode 100, battery cell 10, and battery provided in this application embodiment, by providing multiple spaced-apart receiving holes 1137 in the bending section 113, when the positive electrode 100 is applied to the battery cell 10, the receiving holes 1137 can provide expansion space for the expansion of the negative electrode 200, so as to allow the negative electrode 200 in the corner area 400 of the battery cell 10 to expand and contract, which helps to improve the situation of negative electrode coating peeling and cracking on the negative electrode 200, thereby improving the situation of lithium plating on the surface of the negative electrode 200. By filling each receiving hole 1137 with a flexible filler 130, the flexible filler 130 can generate elastic deformation when compressed, so when the negative electrode 200 expands and squeezes the flexible filler 130, the flexible filler 130 can provide expansion space for the negative electrode 200 through elastic deformation, and can support the negative electrode 200, which helps to improve the situation of the corner area 400 of the battery cell 10 bulging due to excessive expansion of the negative electrode 200.

[0084] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A positive electrode sheet characterized by comprising: include: The positive electrode body includes multiple bent sections and multiple straight sections that are alternately connected along the winding direction, wherein the bent sections are provided with multiple spaced-apart receiving holes; as well as A flexible filler is provided in each of the accommodating holes, the flexible filler being configured to undergo elastic deformation under pressure.

2. The positive electrode sheet according to claim 1, characterized by The volume of the flexible filler within the accommodating hole is smaller than the volume of the accommodating hole.

3. The positive electrode sheet according to claim 2, characterized by The flexible filler includes a filling portion and an extension portion connected together. The filling portion fills the accommodating hole and is bonded to the hole wall of the accommodating hole. The extension portion is exposed outside the accommodating hole and is bonded to the outer surface of the positive electrode body. The volume of the filling portion is smaller than the volume of the receiving hole.

4. The positive electrode sheet according to claim 3, characterized by The thickness of the epitaxial portion is ≥1μm and ≤5μm; and / or the maximum distance between the epitaxial portion and the edge of the accommodating hole wall is ≥0.2mm and ≤1mm.

5. The positive electrode sheet according to claim 1, characterized in that, The positive electrode body includes a first positive electrode coating, a substrate layer, and a second positive electrode coating connected sequentially along the thickness direction; The accommodating hole penetrates at least one of the first positive electrode coating and the second positive electrode coating, and also penetrates the substrate layer; the flexible filler connects the first positive electrode coating and the second positive electrode coating, and is a flexible conductive filler.

6. The positive electrode sheet according to claim 5, characterized in that, The flexible filler is a PEDOT / PSS flexible filler.

7. The positive electrode sheet according to claim 1, characterized in that, The diameter of the receiving hole is ≥0.5mm and ≤1.5mm; And / or, the distance between two adjacent receiving holes is ≥0.5mm and ≤2.5mm; And / or, the positive electrode body has two opposite edges spaced apart along the width direction, both edges extending along the winding direction; the distance between the receiving hole closest to the edge and the edge is ≥1mm and ≤5mm.

8. The positive electrode sheet according to claim 1, characterized in that, The positive electrode body has two opposite edges spaced apart along the width direction, and both edges extend along the winding direction; a plurality of receiving holes are arranged in n columns along the winding direction, and each column includes a plurality of receiving holes arranged at intervals along the width direction; wherein, n is an integer ≥1; And / or, the bent section has a perforated area, the perforated area is spaced apart from the straight section, and a plurality of accommodating holes are distributed in the perforated area; a center line is defined extending along the width direction and passing through the center of the bent section along the winding direction, the perforated area has two boundary lines located on opposite sides of the center line along the winding direction, and the distance between each boundary line and the center line along the winding direction is ≥3mm and ≤5mm.

9. A battery cell, characterized in that, Including the positive electrode sheet according to any one of claims 1 to 8.

10. A battery, characterized in that, Includes the battery cell according to claim 9.

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