Battery cell, battery device, and electric device

Abstract

The application belongs to the technical field of batteries, and particularly relates to a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell and an electrode assembly, the electrode assembly comprises a negative electrode sheet, a positive electrode sheet and a separator arranged in a winding mode, the negative electrode sheet comprises a plurality of negative electrode flat parts, the positive electrode sheet comprises a plurality of positive electrode flat parts, the plurality of negative electrode flat parts and the plurality of positive electrode flat parts are arranged in an interleaved and laminated mode, the positive electrode flat part is always opposite to the negative electrode flat part at each position of the flat area of the electrode assembly, and the positive electrode active material is opposite to the negative electrode active material; the positive electrode sheet is provided with a first bending part at the winding starting end facing the negative electrode sheet, the inner surface of the bending part is an insulating surface, the insulating surface does not provide the positive electrode active material to participate in a chemical reaction, and at the bending position of the inner circle of the electrode assembly, the situation that the negative electrode active material is excessive or insufficient due to the positive electrode active material being opposite to the positive electrode active material does not occur, so that the risk of lithium precipitation of the electrode assembly can be reduced.

Description

Technical Field

[0001] This application belongs to the field of battery technology, and in particular relates to a battery cell, a battery device, and an electrical device. Background Technology

[0002] With the development of science and technology, new energy electric vehicles are gradually becoming more widespread. As one of the core components of electric vehicles, the battery is the energy hub, and battery technology is a crucial factor in the development of electric vehicles.

[0003] Batteries typically include electrode assemblies, which can be made from positive electrode sheets, negative electrode sheets, and separators using a winding or stacking process. In electrode assemblies made using a winding process, there are negative electrode sheets facing each other at one or more turns inside the winding structure, meaning there are negative electrode active materials facing each other. The negative electrode active materials at this part of the inner ring cannot be effectively utilized, thus making it difficult to effectively improve the energy density of the electrode assembly.

[0004] The above statements are for the purpose of providing background information in relation to this application only and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this application is to provide a battery cell, a battery device, and an electrical device to improve the problem that the energy density of battery cells is difficult to effectively increase in related technologies.

[0006] The technical solution adopted in the embodiments of this application is:

[0007] In a first aspect, a battery cell is provided, comprising:

[0008] The outer shell has a cavity;

[0009] Electrode assembly, housed within the cavity;

[0010] The electrode assembly includes a positive electrode, a negative electrode, and a separator. The separator is positioned between the positive and negative electrode. The positive electrode, separator, and negative electrode are stacked and wound together. The positive electrode includes multiple straight positive electrode portions and multiple bent positive electrode portions connected to the straight positive electrode portions. The negative electrode includes multiple straight negative electrode portions and multiple bent negative electrode portions connected to the straight negative electrode portions. Along the thickness direction of the electrode assembly, the multiple straight positive electrode portions and the multiple straight negative electrode portions are staggered and stacked.

[0011] The plurality of positive electrode straight sections include a first positive electrode straight section and a second positive electrode straight section, and the plurality of positive electrode bent sections include a first bent section. The first positive electrode straight section is located at the starting end of the winding of the positive electrode sheet along the winding direction, and the second positive electrode straight section is connected to the first positive electrode straight section through the first bent section.

[0012] Multiple negative electrode straight portions include a first negative electrode straight portion, which is located at the starting end of the winding of the negative electrode sheet along the winding direction. Along the thickness direction of the electrode assembly, the first negative electrode straight portion is located between the first positive electrode straight portion and the second positive electrode straight portion, and the first bending portion is provided facing the starting end of the winding of the negative electrode sheet.

[0013] The positive electrode includes an electrode body and a first connector. The electrode body includes a first electrode portion and a second electrode portion. Along the winding direction of the electrode assembly, the second electrode portion and the first electrode portion are spaced apart. The first electrode portion is continuously wound. A first positive electrode straight portion is disposed on the second electrode portion, and a second positive electrode straight portion is disposed on the first electrode portion. The first connector connects the second electrode portion and the first electrode portion along the winding direction. A first bending portion is disposed on the first connector. The first connector is an insulating member. The surface of the first connector facing the center of the electrode assembly is an insulating surface. The two ends of the insulating surface extend to the first positive electrode straight portion and the second positive electrode straight portion. Along the thickness direction of the electrode assembly, the projection of the insulating surface at least partially overlaps with the projection of the first negative electrode straight portion.

[0014] The battery cell of this application embodiment has an electrode assembly including a negative electrode, a positive electrode, and a separator. The negative electrode, positive electrode, and separator are stacked and wound together. The negative electrode includes multiple negative straight portions, and the positive electrode includes multiple positive straight portions. The multiple negative and positive straight portions are staggered and stacked along the thickness direction of the electrode assembly. In this way, at each position in the straight region of the electrode assembly, the positive straight portion is always aligned with the negative straight portion, which satisfies the requirement that the positive active material is aligned with the negative active material. This allows full utilization of the inner space of the electrode assembly to accommodate the active material for reaction and current generation, thereby improving the energy density of the electrode assembly and the battery cell. Furthermore, by breaking the main body of the positive electrode into a first electrode portion and a second electrode portion, and then using a first connector to cover the broken position of the main body and connect the first electrode portion and the second electrode portion to form an integral positive electrode, the first connector is set as an insulating member, so that the surface of the positive electrode... The surface of the first bend at the starting end of the negative electrode, facing the center of the electrode assembly, is an insulating surface. The two ends of this insulating surface extend to partially overlap with the corresponding straight portions of the first or second positive electrode. The insulating surface does not provide positive electrode active material to participate in the chemical reaction. Thus, even at the bend, there will be no excess or insufficient negative electrode active material due to positive electrode active material directly facing each other, even at the inner ring of the electrode assembly. This meets the overcapacity design requirements of the electrode assembly for the negative electrode and reduces the risk of lithium plating. Furthermore, the first connector can cover and protect the cut positions of the first and second electrode portions, covering and shielding the burrs at the cut edges. This reduces the probability of burrs piercing the separator and causing a short circuit. While increasing the energy density of the battery cell, this also ensures the stability and reliability of the battery cell's electrical performance, contributing to improved overall battery cell performance.

[0015] In some embodiments, an insulating layer is provided between the first positive electrode straight portion and the first negative electrode straight portion.

[0016] By adopting the technical solution of this embodiment, the number of insulating materials between the first positive electrode straight section and the first negative electrode straight section is only one layer. That is, while ensuring the insulation between the first positive electrode straight section and the first negative electrode straight section, the inner space of the electrode assembly will not be wasted due to setting too many layers of insulating materials. The electrode assembly can make better use of the space to set active materials, thereby helping to improve the energy density of the electrode assembly.

[0017] In some embodiments, the starting end of the winding of the separator extends beyond the first positive electrode straight portion in a direction opposite to the winding direction of the electrode assembly.

[0018] By adopting the technical solution of this embodiment, the separator completely covers the starting end of the winding of the positive electrode sheet, which can reduce the risk of the positive electrode sheet being exposed due to factors such as the expansion of the positive electrode sheet, and improve the reliability and stability of electrical insulation. Furthermore, since the separator completely covers the starting end of the winding of the positive electrode sheet, the separator can cover burrs, warping, etc. at the break point of the positive electrode sheet, further reducing the risk of short circuits inside the electrode assembly. In some embodiments, the plurality of negative electrode bending portions include a first negative electrode bending portion, and the plurality of negative electrode straight portions also include a second negative electrode straight portion. The second negative electrode straight portion is connected to the first negative electrode straight portion through the first negative electrode bending portion, and the starting end of the winding of the separator is attached to the surface of the first negative electrode bending portion facing the center of the electrode assembly; or, the starting end of the winding of the separator is attached to the surface of the first negative electrode straight portion facing the center of the electrode assembly, and along the thickness direction of the electrode assembly, the projection of the starting end of the winding of the separator does not overlap with the projection of the first positive electrode straight portion.

[0019] In some embodiments, the starting end of the winding of the separator extends beyond the starting end of the winding of the first negative electrode straight portion in a direction opposite to the winding direction of the electrode assembly.

[0020] By adopting the technical solution of this embodiment, the insulating component completely covers the starting end of the winding of the negative electrode sheet, which can reduce the risk of the negative electrode sheet being exposed to the insulating component due to factors such as the expansion of the negative electrode sheet, and improve the reliability and stability of electrical insulation; in addition, the insulating component completely covers the starting end of the winding of the negative electrode sheet, and the insulating component can cover the burrs, warping, etc. at the break of the negative electrode sheet, further reducing the risk of short circuits inside the electrode assembly.

[0021] In some embodiments, the starting end of the winding of the insulating member is attached to the insulating surface, and the projection of the starting end of the winding of the insulating member does not overlap with the projection of the straight portion of the first negative electrode along the thickness direction of the electrode assembly.

[0022] In some embodiments, the length of the overlap between the projection of the insulating surface and the projection of the first negative electrode straight portion is 0.05 mm to 300 mm.

[0023] By adopting the technical solution of this embodiment, the insulating surface has a length region of 0.05mm to 300mm that overlaps with the end of the straight portion of the first negative electrode located in the innermost ring. The lower limit of the length of the overlapping portion is 0.05mm to meet the design requirements of excessive negative electrode active material, and the upper limit of the length of the overlapping portion is 300mm. As an inactive area, the insulating surface will not occupy too much effective space, reducing the risk of battery energy density reduction due to the setting of the insulating surface.

[0024] In some embodiments, the insulating element may be a flexible connector.

[0025] By adopting the technical solution of this embodiment, a flexible first connector is used to replace the electrode body in bending deformation within the bending area, which can reduce the probability of the electrode body breaking in the bending area, thereby reducing the probability of the positive electrode sheet breaking brittlely and puncturing the separator, and further improving the electrical reliability of the electrode assembly and battery cell.

[0026] In some embodiments, the first connector is a polyethylene terephthalate component, a polyimide component, or a polypropylene component.

[0027] In some embodiments, along the winding direction, one end of the first connector is attached to the surface of the first electrode portion, and the other end of the first connector is attached to the surface of the second electrode portion.

[0028] By adopting the technical solution of this embodiment, the first connector covers the surface of the end of the first electrode portion and simultaneously covers the surface of the end of the second electrode portion. Thus, the first connector can also cover and protect the cut positions of the first and second electrode portions, covering and shielding the burrs at the cut edges, reducing the probability of burrs piercing the insulating member and causing a short circuit, and improving the electrical reliability of the electrode assembly.

[0029] In some embodiments, the first connector includes a first sub-part and a second sub-part. One end of the first sub-part is attached to the surface of the first electrode portion facing the center of the electrode assembly, and the other end is attached to the surface of the second electrode portion facing the center of the electrode assembly. One end of the second sub-part is attached to the surface of the first electrode portion facing away from the center of the electrode assembly, and the other end is attached to the surface of the second electrode portion facing away from the center of the electrode assembly.

[0030] By adopting the technical solution of this embodiment, the first electrode portion is connected to the second electrode portion on both sides of the electrode body along the thickness direction. The first sub-part of the first electrode portion covers the burrs on the inner surface of the cut formed by cutting, and the second sub-part covers the burrs on the outer surface of the cut formed by cutting, which further reduces the probability of burrs piercing the insulating member and causing short circuit, and improves the electrical reliability of the electrode assembly.

[0031] In some embodiments, the protrusion thickness of the first sub-part and the second sub-part from the corresponding first electrode portion or second electrode portion is 0.003mm to 2mm.

[0032] By adopting the technical solution of this embodiment, the protrusion thickness of the first sub-part and the protrusion thickness of the second sub-part are set within the above-mentioned thickness range, so that the first connector can not only connect the first electrode part and the second electrode part as well as the ion barrier, but also will not occupy too much space and will not cause a significant reduction in the energy density of the electrode assembly due to the setting of the first connector.

[0033] In some embodiments, the positive electrode further includes at least one second connector, the first electrode portion includes a first electrode segment and at least one second electrode segment, the second electrode portion and the first electrode segment are spaced apart along the winding direction of the electrode assembly, the second electrode segment is spaced apart between the second electrode portion and the first electrode segment, and the first electrode segment is continuously wound.

[0034] The first connector connects the second electrode portion and the adjacent second electrode segment, the second connector connects two adjacent second electrode segments, and / or the second connector connects the adjacent second electrode segment and the first electrode segment, and the second connector is an insulating component.

[0035] By adopting the technical solution of this embodiment, multiple positive electrode bending portions located in the inner ring of the electrode assembly are disposed on the second connector. The second connector can replace part of the electrode body in the bending area, and the second connector replaces part of the electrode body for bending deformation. In this way, after the first electrode portion is broken into a first electrode segment and a second electrode segment, the second connector is used to cover the broken position of the first electrode portion and connect them. The second connector is set as an insulating member, thereby reducing the amount of positive electrode active material at various positions with large curvature in the inner ring of the electrode assembly, so as to meet the design requirements of excessive negative electrode active material.

[0036] In some embodiments, the first electrode portion includes a plurality of second electrode segments, and the positive electrode portion further includes a plurality of second connectors, the second connectors connecting two adjacent second electrode segments and connecting adjacent second electrode segments and the first electrode segment.

[0037] In some embodiments, the second connector is a flexible connector.

[0038] By adopting the technical solution of this embodiment, a flexible second connector is used to replace the electrode body in bending deformation within the bending area, which can further reduce the probability of the positive electrode breaking in the bending area, thereby reducing the probability of the positive electrode breaking brittlely and puncturing the separator, and further improving the electrical reliability of the electrode assembly and battery cell.

[0039] In some embodiments, the second connector is a polyethylene terephthalate component, a polyimide component, or a polypropylene component.

[0040] In some embodiments, the positive electrode sheet further includes a second insulating member, which is spaced apart from the insulating surface along the winding direction of the electrode assembly. The plurality of positive electrode straight portions further include a plurality of third positive electrode straight portions spaced apart along the winding direction of the positive electrode sheet. The plurality of positive electrode bent portions further include a second bent portion and at least one third bent portion. A third positive electrode straight portion is connected to a second positive electrode straight portion through a second bent portion, and two third positive electrode straight portions arranged adjacent to each other along the winding direction are connected through a third bent portion. The second insulating member is attached to the surface of at least the second bent portion facing the center of the electrode assembly.

[0041] By adopting the technical solution of this embodiment, the second bending portion is the bending portion with the largest curvature among the multiple positive electrode bending portions except for the first bending portion. At least a second insulating member is attached to the inner surface of the second bending portion. The second insulating member can block at least a portion of the positive electrode active material disposed at the bending portion, thereby making the amount of negative electrode active material in the electrode assembly at this position greater than that of positive electrode active material, so as to meet the design requirement of excess negative electrode active material.

[0042] In some embodiments, the electrode assembly includes a plurality of second insulating members, which are arranged sequentially and at intervals along the winding direction of the electrode assembly. At least the surface of the first third bend adjacent to the second bend, facing the center of the electrode assembly, is covered with a second insulating member.

[0043] By adopting the technical solution of this embodiment, a second insulating member is attached to the inner surface of multiple positive electrode bends located in the inner ring of the electrode assembly. At the position where the inner ring curvature of the electrode assembly is large, the second insulating member covers part of the positive electrode active material on the inner surface of the positive electrode bend, so that the electrode assembly can meet the design requirements of excess negative electrode active material at each position with large curvature.

[0044] In some embodiments, the second insulating element is a polyethylene terephthalate film, a polyimide film, or a polypropylene film.

[0045] Secondly, a battery device is provided, comprising the aforementioned battery cell.

[0046] The battery device of this application embodiment includes the aforementioned battery cell, and therefore includes at least all the beneficial effects of the aforementioned battery cell, which will not be repeated here.

[0047] Thirdly, an electrical device is provided, including the aforementioned battery cell, and / or, including the aforementioned battery device.

[0048] The electrical device of this application embodiment includes at least one of the above-mentioned battery cell and battery device, and therefore includes all the beneficial effects of the above-mentioned battery cell or battery device, which will not be repeated here.

[0049] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application;

[0052] Figure 2 This is a schematic diagram of the structure of a battery device provided in an embodiment of this application;

[0053] Figure 3 An exploded view of a battery cell provided in an embodiment of this application;

[0054] Figure 4 This is a schematic diagram of the electrode assembly in the related technology;

[0055] Figure 5 Schematic diagram of the electrode assembly provided in the embodiments of this application Figure 1 ;

[0056] Figure 6 Schematic diagram of the electrode assembly provided in the embodiments of this application Figure 2 ;

[0057] Figure 7 for Figure 5 Enlarged view at point A in the middle;

[0058] Figure 8 for Figure 5 The diagram shows the structure of the positive electrode of the electrode assembly (when the first insulating element is attached) in a wound state;

[0059] Figure 9 for Figure 5 A partial cross-sectional view of the electrode assembly shown, with the first insulating element attached to the positive electrode plate (before it is wound);

[0060] Figure 10 A flowchart illustrating a first method for manufacturing an electrode assembly provided in this application embodiment;

[0061] Figure 11 A schematic diagram of a winding method used to produce the electrode assembly provided in the embodiments of this application during winding;

[0062] Figure 12 A schematic diagram of another winding method used in the production of the electrode assembly provided in the embodiments of this application;

[0063] Figure 13 Schematic diagram of the electrode assembly provided in the embodiments of this application Figure 3 ;

[0064] Figure 14 for Figure 13 The diagram shows the structure of the positive electrode plate of the electrode assembly (when the first insulating element and the second insulating element are attached) in the wound state;

[0065] Figure 15 for Figure 13 A partial cross-sectional view of the electrode assembly shown, with the first and second insulating elements attached to the positive electrode plate (before it is wound);

[0066] Figure 16 A flowchart illustrating a second method for manufacturing an electrode assembly provided in this application embodiment;

[0067] Figure 17 Schematic diagram of the electrode assembly provided in the embodiments of this application Figure 4 ;

[0068] Figure 18 for Figure 17 Enlarged view at point B;

[0069] Figure 19 for Figure 17 The diagram shows the structure of the electrode assembly when the positive electrode is in a wound state;

[0070] Figure 20 for Figure 17 A partial view of the cross-sectional view of the positive electrode of the electrode assembly shown before it is wound;

[0071] Figure 21 A flowchart illustrating a third method for manufacturing an electrode assembly provided in this application embodiment;

[0072] Figure 22 Schematic diagram of the electrode assembly provided in the embodiments of this application Figure 5 ;

[0073] Figure 23 for Figure 22 The diagram shows the structure of the electrode assembly when the positive electrode is in a wound state;

[0074] Figure 24 for Figure 22 A partial view of the cross-sectional view of the positive electrode of the electrode assembly shown before it is wound;

[0075] Figure 25 A flowchart illustrating a fourth method for manufacturing an electrode assembly provided in this application embodiment;

[0076] Figure 26 Schematic diagram of the electrode assembly provided in the embodiments of this application Figure 6 .

[0077] The following are the labeling elements in the figure:

[0078] 100. Vehicle; 101. Controller; 102. Motor;

[0079] 200. Battery device;

[0080] 10. Battery cell; 11a. Electrode assembly; 11. Positive electrode; 111. Straight positive electrode portion; 111a. First straight positive electrode portion; 111b. Second straight positive electrode portion; 111c. Third straight positive electrode portion; 112. Bent positive electrode portion; 112a. First bent portion; 112b. Second bent portion; 112c. Third bent portion; 1121. Insulating surface; 113. Electrode body; 1131. First electrode portion; 11311. First electrode segment; 11312. Second electrode segment; 1132. Second electrode portion; 114. First insulating component; 115. Second insulating component; 116. First connector; 1161. First sub-part; 1162. Second sub-part; 117. Second connector; 1171. Third sub-part; 1172. Fourth sub-part; 12. Negative electrode plate; 121. Straight negative electrode portion; 121a. First straight negative electrode portion; 121b. Second straight negative electrode portion; 122. Negative electrode bent portion; 122a. First bent negative electrode portion; 13. Isolator; 14. Straight area; 15. Bent area; 1101. Electrode tab; 120. Outer shell; 1210. Cavity; 1201. Shell body; 1202. End cap; 1203. Electrode terminal;

[0081] 20. Box body; 201. Accommodation space; 21. First part; 22. Second part;

[0082] 30. Coiling needles. Detailed Implementation

[0083] To make the technical problem to be solved, the technical solution and the beneficial effects of this application clearer, the following is in conjunction with the appendix. Figures 1 to 26 The embodiments described herein will be used to further illustrate this application in detail. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0084] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0085] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0086] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least some of the embodiments of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments in any suitable manner.

[0087] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0088] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "Several" means one or more, unless otherwise explicitly specified.

[0089] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or component 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 the embodiments of this application.

[0090] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0091] In the description of the embodiments in this application, unless otherwise expressly specified and limited, when a component is referred to as "fixed to" or "set on" another component, it may be directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it may be directly connected to or indirectly connected to the other component.

[0092] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0093] Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical solutions. Unless otherwise specified, all steps of this application can be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0094] A battery cell, as the smallest unit comprising a battery, typically includes a casing and an electrode assembly housed within the casing. The electrode assembly has tabs, and the casing has electrode terminals. The tabs of the electrode assembly connect to the electrode terminals to enable the input and output of electrical energy. The electrode assembly is the component within the battery cell where the electrochemical reaction occurs. The electrode assembly can be manufactured using a winding or laminating process, comprising a positive electrode, a negative electrode, and a separator. The positive electrode may include a positive current collector and a positive active material disposed on the surface of the positive current collector. The negative electrode may include a negative current collector and a negative active material disposed on the surface of the negative current collector. The separator is disposed between the positive and negative electrodes to prevent short circuits between the positive and negative electrodes, while also allowing active ions to pass through.

[0095] In the battery field, lithium-ion batteries have been widely used in new energy vehicles, energy storage, and other fields due to their advantages such as high energy density and long cycle life. In related technologies, for lithium-ion batteries, during the first charge, the reaction between the negative electrode and the electrolyte forms a solid electrolyte interface (SEI) film on the surface of the negative electrode. The SEI film has the characteristics of an ionic conductor and an electronic insulator, allowing lithium ions to pass through while isolating electrons. The SEI film is fundamental to the operation of lithium-ion batteries. Therefore, when manufacturing electrode components, the negative electrode capacity needs to be over-designed, meaning the actual CB value is greater than the designed CB value (where CB is the ratio of the product of the negative electrode areal density and the negative electrode specific capacity to the product of the positive electrode areal density and the positive electrode specific capacity). This ensures that the negative electrode capacity meets the lithium-ion intercalation requirements while also providing sufficient negative electrode capacity for SEI film formation.

[0096] In related technologies, for electrode assemblies employing a wound structure, the structural characteristic is that the positive electrode, negative electrode, and separator are wound together to form a cylindrical or flat cylindrical wound structure. The curvature of the wound structure varies at different positions. In actual design, considering the curvature of the wound structure, the negative electrode needs to be wrapped around the outside of the positive electrode to meet the excess CB value requirement. Therefore, when manufacturing electrode assemblies using a wound process, the wound structure first winds two layers of separators, such as a separator film, once or more. Then, starting from the second or even the third or fourth turn, the negative electrode is inserted between the two layers of separators. The negative electrode is wound together with the separators for a period of time. Then, the positive electrode is placed on the outer layer of the separators, away from the negative electrode, and wound. At the end of the winding, two separate layers of separators need to be wound at least one more turn to finish, so that the negative electrode can wrap around the positive electrode at any position in the electrode assembly. In electrode assemblies manufactured in this way, there may be negative electrode sheets that are only covered and wound by insulating materials in one or more turns inside the electrode assembly. That is, there may be negative electrode sheets facing each other and negative active materials facing each other in one or more turns inside the electrode assembly. The negative active materials in this part of the inner ring cannot be effectively utilized, which makes it difficult to effectively improve the energy density of the electrode assembly.

[0097] Based on this, this application provides a battery cell whose electrode assembly includes a negative electrode, a positive electrode, and a separator. The negative electrode, positive electrode, and separator are stacked and wound together. The negative electrode includes multiple negative straight portions, and the positive electrode includes multiple positive straight portions. These multiple negative and positive straight portions are staggered and stacked along the thickness direction of the electrode assembly. This ensures that at all positions in the straight region of the electrode assembly, the positive straight portion is always aligned with the negative straight portion, thus satisfying the requirement that the positive active material is aligned with the negative active material. This allows for full utilization of the inner space of the electrode assembly to accommodate the active material for reaction and current generation, thereby improving the energy density of the electrode assembly and the battery cell. Furthermore, the positive electrode has a face towards the negative electrode. The first bend at the starting end of the winding has an insulating surface facing the center of the electrode assembly. The two ends of this insulating surface extend to partially overlap with the corresponding first or second positive electrode straight section. The insulating surface does not provide positive electrode active material for chemical reaction. Thus, even at the bend, within the inner ring of the electrode assembly, there will be no excess or deficiency of negative electrode active material due to positive electrode active material directly facing each other. This satisfies the electrode assembly's design requirement for excessive negative electrode capacity, reduces the risk of lithium plating, and while increasing the energy density of the battery cell, ensures the stability and reliability of the battery cell's electrical performance, thereby contributing to improved overall battery cell performance.

[0098] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0099] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0100] For ease of explanation, an electrical device is provided in one embodiment of this application, which is illustrated using a vehicle as an example.

[0101] Please refer to Figure 1 , Figure 1This is a schematic diagram of the structure of a vehicle 100 provided in some embodiments of this application. The vehicle 100 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 200 is provided inside the vehicle 100, and the battery device 200 can be located at the bottom, front, or rear of the vehicle 100. The battery device 200 can be used to power the vehicle 100; for example, the battery device 200 can serve as the operating power source for the vehicle 100. The vehicle 100 may also include a controller 101 and a motor 102. The controller 101 is used to control the battery device 200 to supply power to the motor 102, for example, to meet the power needs of the vehicle 100 during starting, navigation, and driving.

[0102] In some embodiments, the battery device 200 can not only serve as the operating power source for the vehicle 100, but also as the driving power source for the vehicle 100, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 100.

[0103] Please refer to the following: Figure 2 and Figure 3 This application also provides a battery device 200. The battery device 200 may include one or more battery cell groups for providing voltage and capacity. Each battery cell group may include multiple battery cells 10, which are connected in series, parallel, or mixed connections via a busbar.

[0104] In some embodiments, the battery device 200 includes a battery management system, which is a core component responsible for monitoring and managing the status of individual battery cells 10. Its main functions include: real-time monitoring of parameters such as voltage, current, and temperature of individual battery cells 10 to ensure that the battery is in a safe working state; balancing the charge of each individual battery cell 10 in the battery cell group through active or passive means to extend the battery life; controlling and regulating the temperature of individual battery cells 10 to avoid performance degradation or safety risks caused by overheating or overcooling; detecting faults in the battery cell group and the BMS itself, and taking corresponding protective measures, such as cutting off power and alarming.

[0105] As an example, the battery management system can be housed in the enclosure 20 to support and protect the battery management system.

[0106] As an example, the battery management system can also be located outside the housing 20 and connected to the battery cells 10, sensors and other devices inside the housing 20 via wires.

[0107] In some embodiments, a battery cell pack is typically formed by arranging a plurality of battery cells 10.

[0108] As an example, a battery cell group can be a battery module, which is formed by arranging and fixing multiple battery cells 10 into an independent module. As an example, a battery module can be formed by bundling multiple battery cells 10 together with cable ties.

[0109] In some embodiments, the battery device 200 may be a battery pack, which includes a housing 20 and one or more battery cell groups housed in the housing 20.

[0110] As an example, the battery cell pack can be a battery module, and the battery cell pack can be housed in the housing 20 by fixing the battery module in the housing 20.

[0111] As an example, the battery cell pack can also be housed in the housing 20 by directly fixing multiple battery cells 10 to the housing 20.

[0112] In some embodiments, the housing 20 has an internal receiving space 201 to accommodate the battery cell 10. The housing 20 can be made of a material with a certain degree of hardness and strength, so that the housing 20 is not easily deformed when subjected to compression or impact, enabling the battery to have higher structural strength and improved reliability. The material of the housing 20 can be various, including but not limited to aluminum, stainless steel, aluminum alloy, iron, or plastic.

[0113] In some embodiments, the housing 20 may be part of the chassis structure of the vehicle 100. For example, a portion of the housing 20 may be at least a portion of the floor of the vehicle 100, or a portion of the housing 20 may be at least a portion of the crossbeams and longitudinal beams of the vehicle 100.

[0114] As an example, such as Figure 2 As shown, the housing 20 may include a first part 21 and a second part 22, which are closed together to form a closed receiving space 201 inside the housing 20 for storing the battery cell pack. Here, "closed" refers to covering or shutting down; it can be sealed or unsealed. The first part 21 and the second part can be the top cover or the bottom plate of the housing 20, respectively. The first part 21 and the second part 22 may also both be hollow structures with an opening on one side, with the opening side of the first part 21 covering the opening side of the second part 22.

[0115] As an example, the housing 20 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that the interior of the housing 20 forms a closed receiving space 201 to accommodate the battery cell pack.

[0116] In some embodiments, such as Figure 3As shown, the battery cell 10 includes an electrode assembly 11a and a housing 120. The electrode assembly 11a is installed inside the housing 120 to protect the electrode assembly 11a. The housing 120 may contain one or more electrode assemblies 11a.

[0117] The outer casing 120 is a structure in the battery cell 10 used to protect the electrode assembly 11a. The outer casing 120 may include a hollow shell body 1201 with an opening and an end cap 1202 covering the opening end of the shell body 1201. The end cap 1202 is provided with electrode terminals 1203. The electrode assembly 11a is disposed inside the shell body 1201. The tabs 1101 of the electrode assembly 11a are connected to the electrode terminals 1203 to realize the input and output of electrical energy.

[0118] In some embodiments, electrode assembly 11a is a component in the battery cell 10 where an electrochemical reaction occurs. Electrode assembly 11a may be entirely housed within housing 120 or partially housed within housing 120. For example, a portion of the tab 1101 of electrode assembly 11a may extend outside housing 120, or electrode assembly 11a may be entirely housed within housing 120.

[0119] In some embodiments, such as Figure 4 As shown, the electrode assembly 11a includes a positive electrode 11 and a negative electrode 12. During the charging and discharging process of the battery cell 10, lithium ions are inserted and extracted back and forth between the positive electrode 11 and the negative electrode 12.

[0120] In some embodiments, the positive electrode 11 may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0121] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0122] As an example, the positive current collector can be a composite current collector. A composite current collector may include a polymer substrate and an aluminum layer. The composite current collector can be formed by coating an aluminum or aluminum alloy onto the surface of a polymer substrate (such as a substrate made of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0123] As an example, the positive electrode active material includes positive electrode active materials, which may include at least one of the following materials: lithium phosphates, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0124] In some embodiments, the negative electrode 12 may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0125] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0126] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0127] As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, and tin-based materials. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0128] In some embodiments, such as Figure 4 As shown, the electrode assembly 11a also includes a separator 13, which is disposed between the positive electrode 11 and the negative electrode 12. The separator 13 can prevent short circuits between the positive and negative electrodes, while allowing active ions to pass through.

[0129] In some embodiments, the separator 13 is a separator membrane. The separator membrane of this application can be any known porous structure separator membrane with good chemical and mechanical stability.

[0130] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different. The separator 13 can be a single component located between the positive electrode 11 and the negative electrode 12, or it can be attached to the surface of the positive electrode 11 or the surface of the negative electrode 12. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0131] In some embodiments, the battery cell 10 further includes an electrolyte that acts as a conductor of ions between the positive electrode 11 and the negative electrode 12. The electrolyte used in this application can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0132] In some embodiments, such as Figure 4 As shown, the electrode assembly 11a has a wound structure. Exemplarily, both the positive electrode 11 and the negative electrode 12 are strip structures. The positive electrode 11, the separator 13, and the negative electrode 12 are sequentially stacked and continuously wound to form a wound body. The electrode assembly 11a includes a straight region 14 and a bent region 15. After winding, the formed wound body of the electrode assembly 11a needs to undergo a shaping process. During the shaping process, the wound body is shaped and pressed to form a flat wound structure, thereby forming the straight region 14 and the bent region 15 within this flat structure. The straight region 14 refers to the area in the electrode assembly 11a where the portion formed after shaping and pressing is straight, and the bent region 15 refers to the area in the electrode assembly 11a where the portion formed after shaping and pressing is bent. Bending regions 15 are formed on opposite sides of the straight region 14. In the winding direction, the straight region 14 and the bent region 15 are alternately arranged and connected.

[0133] For the electrode assembly 11a with a wound structure, considering the curvature of the wound structure, the negative electrode 12 needs to be wrapped around the outside of the positive electrode 11 to meet the excess capacity requirement of the negative electrode.

[0134] The following, in conjunction with the appendix Figures 5 to 25 The battery cell 10 of this application will be described in detail below with specific embodiments. In the embodiments of this application, the winding direction of the electrode assembly 11a is the direction shown by arrow F, the opposite direction of the winding direction of the electrode assembly 11a is the direction shown by arrow F', the thickness direction of the electrode assembly 11a (i.e. the direction perpendicular to the straight area 14) is the direction shown by arrow F1, and the direction perpendicular to the thickness direction of the electrode assembly 11a (i.e., the direction parallel to the straight area 14) is the direction shown by arrow F2.

[0135] In the embodiments of this application, such as Figures 5 to 8 As shown, the battery cell 10 includes a housing 120 and an electrode assembly 11a. The housing 120 is provided with a cavity 1210 (please refer to the diagram). Figure 3 Electrode assembly 11a is disposed within cavity 1210; electrode assembly 11a includes negative electrode 12, positive electrode 11 and separator 13, separator 13 is provided between positive electrode 11 and negative electrode 12, positive electrode 11, separator 13 and negative electrode 12 are stacked and wound together, positive electrode 11 includes multiple positive electrode straight portions 111 and multiple positive electrode bent portions 112 connected to positive electrode straight portions 111, negative electrode 12 includes multiple negative electrode straight portions 121 and multiple negative electrode bent portions 122 connected to negative electrode straight portions 121, multiple positive electrode straight portions 111 and multiple negative electrode straight portions 121 are staggered and stacked along the thickness direction of electrode assembly 11a.

[0136] The plurality of positive electrode straight portions 111 include a first positive electrode straight portion 111a and a second positive electrode straight portion 111b, and the plurality of positive electrode bent portions 112 include a first bent portion 112a. The first positive electrode straight portion 111a is located at the starting end of the winding of the positive electrode sheet 11 along the winding direction, and the second positive electrode straight portion 111b is connected to the first positive electrode straight portion 111a through the first bent portion 112a. The plurality of negative electrode straight portions 121 include a first negative electrode straight portion 121a, which is located at the starting end of the winding of the negative electrode sheet 12 along the winding direction, along the thickness of the electrode assembly 11a. The first negative electrode straight portion 121a is located between the first positive electrode straight portion 111a and the second positive electrode straight portion 111b. The first bent portion 112a is provided facing the starting end of the winding of the negative electrode sheet 12. The first bent portion 112a has an insulating surface 1121 facing the center of the electrode assembly 11a. Along the winding direction of the electrode assembly 11a, the two ends of the insulating surface 1121 extend to the first positive electrode straight portion 111a and the second positive electrode straight portion 111b. Along the thickness direction of the electrode assembly 11a, the projection of the insulating surface 1121 at least partially overlaps with the projection of the first negative electrode straight portion 121a.

[0137] Among them, such as Figures 17 to 19 As shown, the positive electrode 11 includes an electrode body 113 and a first connector 116. The electrode body 113 includes a first electrode portion 1131 and a second electrode portion 1132. Along the winding direction of the electrode assembly 11a, the second electrode portion 1132 and the first electrode portion 1131 are arranged at intervals. The first electrode portion 1131 is continuously wound. A first positive electrode straight portion 111a is provided on the second electrode portion 1132, and a second positive electrode straight portion 111b is provided on the first electrode portion 1131. The first connector 116 connects the second electrode portion 1132 and the first electrode portion 1131 along the winding direction. A first bending portion 112a is provided on the first connector 116. The first connector 116 is an insulating member. The surface of the first connector 116 facing the center of the electrode assembly 11a is an insulating surface 1121.

[0138] In the embodiments of this application, such as Figure 3As shown, the battery cell 10 includes an electrode assembly 11a, which is the core component of the battery cell 10 for storing and releasing electrical energy. It achieves the charging and discharging function of the battery cell 10 through internal chemical reactions. The battery cell 10 also includes a casing 120, which is a shell structure with internal space. The casing 120 has a cavity 1210 for accommodating the electrode assembly 11a and protecting it. The casing can be made of a material with certain hardness and strength, so that it is not easily deformed under pressure or impact, giving the battery cell 10 higher structural strength and improved reliability. The casing material can be various, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, and plastic. The electrode assembly 11a is located within the cavity 1210, meaning that part or all of the electrode assembly 11a is located within the casing 120.

[0139] In the embodiments of this application, such as Figure 5 As shown, the electrode assembly 11a includes a positive electrode 11, a negative electrode 12, and a separator 13 (such as a separator film). The separator 13 is disposed between adjacent positive electrode 11 and negative electrode 12, separating the positive electrode 11 and negative electrode 12. The positive electrode 11, negative electrode 12, and the separator 13 separating the positive electrode 11 and negative electrode 12 are stacked in sequence, and then wound into a compact cylindrical structure or an elliptical cylindrical structure by a winding mechanism. Finally, it is pressed and shaped into a flat wound structure by a shaping structure, for example, wound along the winding direction indicated by arrow F in the figure. The winding mechanism refers to the structure used to wind the positive electrode 11, negative electrode 12, and separator 13. For example, the winding mechanism may include a winding needle 30 for fixing the positive electrode 11, negative electrode 12, and separator 13, and may also include a pressing member, an adhesive applicator, a cutting member, etc., for finishing processing.

[0140] In the embodiments of this application, it can be understood that the positive electrode 11 has a structure with positive active material coated on both sides, and the negative electrode 12 has a structure with negative active material coated on both sides. Exemplarily, positive active material is coated on both surfaces of the positive current collector to form the positive electrode 11, and negative active material is coated on both surfaces of the negative current collector to form the negative electrode 12.

[0141] In the embodiments of this application, such as Figure 5As shown, the electrode assembly 11a includes a flat region 14 and a bent region 15. After winding, the electrode assembly 11a needs to undergo a shaping process. During the shaping process, the wound body is shaped and pressed into a flat structure, thereby forming the flat region 14 and the bent region 15 in this flat structure. The flat region 14 refers to the area in the electrode assembly 11a where the flat part is formed after shaping and pressing, and the bent region 15 refers to the area in the electrode assembly 11a where the bent part is formed after shaping and pressing. Bending regions 15 are formed on opposite sides of the flat region 14. Along the winding direction of the electrode assembly 11a, the flat region 14 and the bent region 15 are arranged alternately and connected. That is, along the winding direction F, two adjacent flat regions 14 are connected by a bent region 15. It should be noted that the winding direction is unidirectional, that is, the winding direction is the direction in which the positive electrode 11 and the negative electrode 12 are continuously wound from the inside to the outside.

[0142] Based on this, such as Figure 5 As shown, the negative electrode 12 includes multiple negative electrode straight portions 121, which are stacked and arranged in the straight region 14. That is, on each winding layer of the electrode assembly 11a, the portion of the negative electrode 12 located in the straight region 14 corresponds to the negative electrode straight portion 121. The multiple negative electrode straight portions 121 are stacked and arranged along the thickness direction of the electrode assembly 11a, that is, perpendicular to the straight region 14. The positive electrode 11 includes multiple positive electrode straight portions 111, which are stacked and arranged in the straight region 14. That is, on each winding layer of the electrode assembly 11a, the portion of the positive electrode 11 located in the straight region 14 corresponds to the positive electrode straight portion 111. The multiple positive electrode straight portions 111 are stacked and arranged along the thickness direction of the electrode assembly 11a, that is, perpendicular to the straight region 14.

[0143] Along the thickness direction of the electrode assembly 11a, multiple negative electrode straight portions 121 and multiple positive electrode straight portions 111 are staggered and stacked. In the straight region 14 of the electrode assembly 11a, a stacked structure is formed in which one negative electrode straight portion 121, one positive electrode straight portion 111, another negative electrode straight portion 121 and another positive electrode straight portion 111 are staggered and stacked. That is, the negative electrode straight portion 121 and the positive electrode straight portion 111 are staggered and stacked and separated by the separator 13. For example, they are stacked in the form of one positive electrode straight portion 111, one separator 13 (such as a separator membrane) and one negative electrode straight portion 121.

[0144] like Figure 5 and Figure 7As shown, the positive electrode 11 also includes multiple positive electrode bending portions 112, which are connected to the ends of the positive electrode straight portions 111. That is, on each winding layer of the electrode assembly 11a, the portion of the positive electrode 11 located in the bending region 15 corresponds to the positive electrode bending portion 112. The multiple positive electrode bending portions 112 are stacked in a direction perpendicular to the thickness direction of the electrode assembly 11a. The negative electrode 12 also includes multiple negative electrode bending portions 122, which are connected to the ends of the negative electrode straight portions 121. That is, on each winding layer of the electrode assembly 11a, the portion of the negative electrode 12 located in the bending region 15 corresponds to the negative electrode bending portion 122. The multiple negative electrode bending portions 122 are stacked in a direction perpendicular to the thickness direction of the electrode assembly 11a. The multiple negative electrode bending portions 122 and the multiple positive electrode bending portions 112 are staggered and stacked and isolated and insulated by the separator 13. For example, they can be stacked in the form of a positive electrode bending section 112, an insulating element 13 (such as an insulating membrane), and a negative electrode bending section 122.

[0145] Among the multiple positive electrode straight sections 111, the two positive electrode straight sections 111 located in the innermost ring of the electrode assembly 11a are the first positive electrode straight section 111a and the second positive electrode straight section 111b. The first positive electrode straight section 111a refers to the first positive electrode straight section formed by the winding starting end of the positive electrode sheet 11 being wound around the innermost ring by a winding mechanism and shaped and pressed by a shaping operation. The second positive electrode straight section 111b refers to the second positive electrode straight section formed by the winding mechanism and shaped and pressed by a shaping operation of a section of the positive electrode sheet 11 located downstream of the first positive electrode straight section 111a. The portion of the positive electrode sheet 11 connected between the first positive electrode straight section 111a and the second positive electrode straight section 111b is the first bending section among the multiple positive electrode bending sections 112, namely the first bending section 112a.

[0146] Among the multiple negative electrode straight portions 121, the two negative electrode straight portions 121 located in the innermost ring of the electrode assembly 11a are the first negative electrode straight portion 121a and the second negative electrode straight portion 121b. The first negative electrode straight portion 121a refers to the first negative electrode straight portion formed by the winding starting end of the negative electrode sheet 12 being wound around the innermost ring by a winding mechanism and shaped and pressed by a shaping operation. The second negative electrode straight portion 121b refers to the second negative electrode straight portion formed by the winding mechanism and shaped and pressed by a shaping operation of a section of the negative electrode sheet 12 downstream of the first negative electrode straight portion 121a. The portion of the negative electrode sheet 12 connecting the first negative electrode straight portion 121a and the second negative electrode straight portion 121b is located within the bending area 15.

[0147] In this embodiment, the first negative electrode straight portion 121a is located between the first positive electrode straight portion 111a and the second positive electrode straight portion 111b. The first bent portion 112a is disposed facing the winding start end of the negative electrode sheet 12, i.e., the first negative electrode straight portion 121a. Thus, at the innermost ring of the electrode assembly 11a, the two opposite sides of the first negative electrode straight portion 121a are respectively disposed opposite to the first positive electrode straight portion 111a and the second positive electrode straight portion 111b. The positive electrode active material can react with the negative electrode active material on the first negative electrode straight section 121a, so that the positive electrode straight section 111 can be kept facing the negative electrode straight section 121 at any position in the straight region 14 of the electrode assembly 11a, that is, the positive electrode active material is facing the negative electrode active material, and there is no situation of negative electrode active material facing negative electrode active material. This allows the active material to be placed in the winding space of the electrode assembly 11a, especially the inner ring space, to react and generate current, which helps to improve the energy density of the electrode assembly 11a and the battery cell 10.

[0148] In the embodiments of this application, such as Figure 5 , Figure 7 and Figures 17 to 19 As shown, the first bending portion 112a has an insulating surface 1121 facing the center of the electrode assembly 11a. The positive electrode sheet 11 includes multiple positive electrode bending portions 112 disposed in the bending region 15. Along the winding direction of the electrode assembly 11a, one of the multiple positive electrode bending portions 112 located at the winding start end is the first bending portion 112a, i.e., the first bending portion formed after the winding start end of the positive electrode sheet 11 is wound around the innermost loop by the winding mechanism and shaped and pressed by a shaping operation. This first bending portion 112a has an insulating surface 1121 facing the winding center of the electrode assembly 11a. The insulating surface refers to a surface that does not provide positive electrode active material to actively participate in the target chemical reaction. For example, the insulating surface 1121 can be formed by attaching an insulating component (such as polyethylene terephthalate or polyimide) to isolate the positive electrode active material on the positive electrode current collector. Figure 5 and Figure 7 As shown, alternatively, the positive electrode 11 can be partially cut, and then the cut ends can be connected with an insulating component (such as a polyethylene terephthalate component or a polyimide component), so that the first bent portion 112a is disposed on the insulating component, and the surface of the insulating component facing the electrode assembly 11a is the insulating surface 1121, such as... Figures 17 to 19 As shown.

[0149] As an example, such as Figures 17 to 19As shown, the positive electrode 11 includes an electrode body 113 and a first connector 116. The electrode body 113 includes a first electrode portion 1131 and a second electrode portion 1132 spaced apart along the winding direction. The first connector 116 connects the first electrode portion 1131 and the second electrode portion 1132. That is, the positive electrode 11 includes three parts, one of which is the first electrode portion 1131 and the other is the second electrode portion 1132. The two are spaced apart along the winding direction of the electrode assembly 11a. The first electrode portion 1131 is continuously wound along the winding direction. The second electrode portion 1132 is spaced apart upstream of the first electrode portion 1131 along the winding direction. The first connector 116 connects the end of the second electrode portion 1132 and the beginning of the first electrode portion 1131 along the winding direction, thereby connecting the first electrode portion 1131 and the second electrode portion 1132 into a whole positive electrode 11 with a strip structure. Furthermore, after the positive electrode 11 is wound, a portion of the first connector 116 is located within the bending region 15. The opposite ends of the first connector 116 extend into the straight region 14 to connect the first electrode portion 1131 and the second electrode portion 1132. The first bending portion 112a of the positive electrode 11 is provided on the first connector 116, and the surface of the first connector 116 facing the center of the electrode assembly 11a forms an insulating surface 1121. In this way, the first connector 116 can replace a portion of the electrode body 113 and bend and deform in the bending region 15, and the first connector 116 can replace a portion of the electrode body 113. By breaking the electrode body 113 into a first electrode portion 1131 and a second electrode portion 1132, and then using a first connector 116 to cover the broken position of the electrode body 113 and connect the first electrode portion 1131 and the second electrode portion 1132 to form an integral positive electrode 11, and setting the first connector 116 as an insulating component, the excess design requirement of the negative electrode active material can be met.

[0150] In the embodiments of this application, such as Figure 5 , Figure 7 and Figures 17 to 19As shown, along the winding direction of the electrode assembly 11a, the two opposite ends of the insulating surface 1121 extend to the first positive electrode straight portion 111a and the second positive electrode straight portion 111b, and partially overlap with the corresponding first positive electrode straight portions 111a and 111b, such that along the thickness direction of the electrode assembly 11a, the projection of the insulating surface 1121 overlaps with the end of the projection of the first negative electrode straight portion 121a. That is, the main body of the insulating surface 1121 covers the first bent portion 112a, the two opposite ends of the insulating surface 1121 extend beyond the bent region 15 and continue to the straight region 14, the portion extending to the straight region 14 covers the end of the first positive electrode straight portion 111a and the end of the second positive electrode straight portion 111b, and also overlaps at least with the end of the first negative electrode straight portion 121a located between the first positive electrode straight portion 111a and the second positive electrode straight portion 111b. Thus, with the thickness direction of the electrode assembly 11a as the projection direction, the projection of the first negative electrode straight portion 121a located in the innermost ring of the electrode assembly 11a can cover the portion of the adjacent first positive electrode straight portion 111a and second positive electrode straight portion 111b that has positive electrode active material.

[0151] In this way, the end of the first negative electrode straight portion 121a located in the innermost ring of the electrode assembly 11a is provided facing the insulating surface 1121, and the innermost ring of the electrode assembly 11a will not have a situation where the positive electrode active material is more than the negative electrode active material due to the corner, so that the first negative electrode straight portion 121a in the innermost ring has an excessive amount of negative electrode active material.

[0152] The battery cell 10 of this embodiment includes an electrode assembly comprising a negative electrode 12, a positive electrode 11, and a separator 13. The negative electrode 12, the positive electrode 11, and the separator 13 are stacked and wound together. The negative electrode 12 includes a plurality of negative electrode straight portions 121, and the positive electrode 11 includes a plurality of positive electrode straight portions 111. The plurality of negative electrode straight portions 121 and the plurality of positive electrode straight portions 111 are staggered and stacked along the thickness direction of the electrode assembly 11a. In this way, at each position of the straight region 14 of the electrode assembly 11a, the positive electrode straight portion 111 is always aligned with the negative electrode straight portion 121, thus satisfying the positive electrode... The active material faces the negative electrode active material, thus fully utilizing the inner space of the electrode assembly 11a to accommodate the active material for reaction and current generation, thereby increasing the energy density of the electrode assembly 11a and the battery cell 10. Furthermore, by breaking the electrode body 113 of the positive electrode 11 into a first electrode portion 1131 and a second electrode portion 1132, and then using a first connector 116 to cover the broken position of the electrode body 113 and connect the first electrode portion 1131 and the second electrode portion 1132 to form an integral positive electrode 11, the first connector 116 is provided. As an insulating component, the surface of the first bend 112a of the positive electrode 11 facing the starting end of the winding of the negative electrode 12, which faces the center of the electrode assembly 11a, is an insulating surface 1121. The two ends of this insulating surface 1121 extend to partially overlap with the corresponding first positive electrode straight portion 111a or second positive electrode straight portion 111b. The insulating surface 1121 does not provide positive electrode active material to participate in the chemical reaction. Thus, even at the bend, within the inner ring of the electrode assembly 11a, there will be no over-contamination of negative electrode active material due to positive electrode active material directly facing positive electrode active material. In cases of insufficient quantity, it can meet the over-design requirements of the electrode assembly 11a for the negative electrode capacity, reducing the risk of lithium plating in the electrode assembly 11a. In addition, the first connector 116 can also cover and protect the cut positions of the first electrode portion 1131 and the second electrode portion 1132, so as to cover and block the burrs at the cut formed by the cut, reducing the probability of burrs piercing the separator 13 and causing short circuit. While improving the energy density of the battery cell 10, it can also provide a guarantee for improving the stability and reliability of the electrical performance of the battery cell 10, which helps to improve the overall performance of the battery cell 10.

[0153] In some embodiments, such as Figure 5 , Figure 7 and Figure 17 and Figure 18 As shown, the length of the overlapping portion of the projection of the insulating surface 1121 and the first negative electrode straight portion 121a is 0.05mm to 300mm.

[0154] In the embodiments of this application, such as Figure 7As shown, the end of the insulating surface 1121 that extends beyond the bending area 15 extends to the straight area 14. The length W of the portion extending to the straight area 14 is 0.05mm to 300mm. Along the thickness direction of the electrode assembly 11a, the insulating surface 1121 has a length region of 0.05mm to 300mm that overlaps with the first negative electrode straight portion 121a located in the innermost ring of the electrode assembly 11a. The lower limit of the length of the overlapping portion is 0.05mm to meet the design requirements of excess negative electrode active material, and the upper limit of the length of the overlapping portion is 300mm. As an inactive area, the insulating surface 1121 will not occupy too much effective space in the straight area 14, reducing the risk of reduced battery energy density due to the setting of the insulating surface 1121.

[0155] In a specific embodiment, the length of the overlapping portion between the projection of the insulating surface 1121 and the projection of the first negative electrode straight portion 121a can be 0.05mm, 10mm, 50mm, 100mm, 120mm, 150mm, 180mm, 200mm, 220mm, 250mm, 280mm or 300mm, etc. The specific value is not limited here, and the design can be selected according to the actual situation.

[0156] Furthermore, in a specific embodiment, it should be noted that, along the direction perpendicular to the thickness of the electrode assembly 11a, both ends of the insulating surface 1121 overlap with the ends of the first negative electrode straight portion 121a located in the innermost ring of the electrode assembly 11a. The length of the overlap between one end of the insulating surface 1121 and the first negative electrode straight portion 121a can be equal to or unequal to the length of the overlap between the other end of the insulating surface 1121 and the first negative electrode straight portion 121a. For example, the length of the overlap between one end of the insulating surface 1121 and the first negative electrode straight portion 121a can be 100 mm, and the length of the overlap between the other end of the insulating surface 1121 and the first negative electrode straight portion 121a can be 100 mm or not.

[0157] In some embodiments, such as Figures 5 to 7 As shown, a separator 13 is provided between the first positive electrode straight portion 111a and the first negative electrode straight portion 121a.

[0158] In this embodiment, only one layer of insulating member 13 is provided between the first positive electrode straight portion 111a and the first negative electrode straight portion 121a located in the innermost ring of the electrode assembly 11a. In this way, the adjacent first positive electrode straight portions 111a and first negative electrode straight portions 121a can be insulated by this layer of insulating member 13. Moreover, the number of insulating members 13 is only one layer, which satisfies the insulation of the first positive electrode straight portion 111a and the first negative electrode straight portion 121a without wasting the inner ring space of the electrode assembly 11a by setting too many layers of insulating members 13. The electrode assembly 11a can make better use of the space to set the active material, thereby helping to improve the energy density of the electrode assembly 11a.

[0159] It should be noted that, in this embodiment, along the direction opposite to the winding direction of the electrode assembly 11a, the starting end of the insulating member 13 is at least flush with the corresponding first positive electrode straight portion 111a or first negative electrode straight portion 121a. That is, this insulating member 13 disposed between the first positive electrode straight portion 111a and the first negative electrode straight portion 121a can completely cover the corresponding first positive electrode straight portion 111a or first negative electrode straight portion 121a. The phrase "the starting end of the separator 13 is at least flush with the corresponding first positive electrode straight portion 111a or first negative electrode straight portion 121a" means that when the separator 13 covers the positive electrode sheet 11 and begins to be wound, the starting end of the separator 13 is flush with or exceeds the starting end of the first positive electrode straight portion 111a. When the separator 13 covers the negative electrode sheet 12 and begins to be wound, the starting end of the separator 13 is flush with or exceeds the starting end of the first negative electrode straight portion 121a, so that the head of the corresponding positive electrode sheet 11 or negative electrode sheet 12 located in the innermost ring of the electrode assembly 11a can be completely covered by the separator 13.

[0160] In some embodiments, such as Figure 5 and Figure 6 As shown, the starting end of the winding of the separator 13 extends beyond the first positive electrode straight portion 111a in a direction opposite to the winding direction of the electrode assembly 11a.

[0161] That is, in this embodiment, the separator 13 begins to wrap around the positive electrode 11 as it begins to wind. The starting end of the separator 13 extends beyond the starting end of the first positive electrode straight portion 111a of the positive electrode 11, thereby completely enclosing the head of the positive electrode 11 located in the innermost ring of the electrode assembly 11a within the separator 13. In this way, the separator 13 covering the starting end of the winding of the positive electrode 11 can reduce the risk of the positive electrode 11 being exposed to the separator 13 due to factors such as electrode expansion, and improve the reliability and stability of electrical insulation. Furthermore, since the separator 13 completely covers the starting end of the winding of the positive electrode 11 located in the innermost ring of the electrode assembly 11a, the separator 13 can cover burrs, warping, etc. at the break point of the positive electrode 11, further reducing the risk of short circuits occurring inside the electrode assembly 11a.

[0162] Understandably, in a specific embodiment, the plurality of negative electrode bending portions 122 include a first negative electrode bending portion 122a, and the plurality of negative electrode straight portions 121 also include a second negative electrode straight portion 121b. The second negative electrode straight portion 121b is connected to the first negative electrode straight portion 121a through the first negative electrode bending portion 122a, and the starting end of the winding of the insulating member 13 is attached to the surface of the first negative electrode bending portion 122a facing the center of the electrode assembly 11a.

[0163] That is, the portion of the starting end of the separator 13 that extends beyond the starting end of the first positive electrode straight portion 111a can be wound and bent and then accommodated in the bending space of the first negative electrode bent portion 122a.

[0164] Alternatively, in other embodiments, such as Figure 5 As shown, the starting end of the winding of the separator 13 is attached to the surface of the first negative electrode straight portion 121a facing the center of the electrode assembly 11a, and the projection of the starting end of the winding of the separator 13 does not overlap with the projection of the first positive electrode straight portion 111a along the thickness direction of the electrode assembly 11a.

[0165] In this embodiment, as Figure 5 As shown, with the dashed line L as the dividing line, the starting end of the winding of the isolator 13 is located on one side of the dashed line L, and the first positive electrode straight portion 111a is located on the other side of the dashed line L. The projections of the two along the thickness direction of the electrode assembly 11a do not overlap. That is, the starting end of the winding of the isolator 13 can also continue to extend to the first negative electrode straight portion 121a after completely covering the first negative electrode bent portion 122a, making the length of the portion of the isolator 13 that exceeds the first positive electrode straight portion 111a longer, further improving the reliability of the electrical isolation of the isolator 13. Furthermore, the projection of the starting end of the isolator 13 does not overlap with the projection of the first positive electrode straight portion 111a, that is, there is still only one layer of isolator 13 between the first positive electrode straight portion 111a and the first negative electrode straight portion 121a. The starting end of the winding of the isolator 13 will not extend to the space between the first positive electrode straight portion 111a and the first negative electrode straight portion 121a, resulting in wasted space.

[0166] In other embodiments, unlike the embodiments described above, such as Figure 6 As shown, in the direction opposite to the winding direction of the electrode assembly 11a, the winding start end of the separator 13 extends beyond the winding start end of the first negative electrode straight portion 121a.

[0167] That is, in this embodiment, the insulating member 13 begins to wrap around the negative electrode sheet 12, and the starting end of the insulating member 13 extends beyond the starting end of the first negative electrode straight portion 121a of the negative electrode sheet 12, thereby completely covering the head of the negative electrode sheet 12 located in the innermost ring of the electrode assembly 11a within the insulating member 13. In this way, the insulating member 13 covering the starting end of the winding of the negative electrode sheet 12 can reduce the risk of the negative electrode sheet 12 being exposed to the insulating member 13 due to factors such as electrode sheet expansion, and improve the reliability and stability of electrical insulation; furthermore, since the insulating member 13 completely covers the starting end of the negative electrode sheet 12 located in the innermost ring of the electrode assembly 11a, the insulating member 13 can cover burrs, warping, etc. at the break point of the negative electrode sheet 12, further reducing the risk of short circuits inside the electrode assembly 11a.

[0168] In a specific embodiment, the starting end of the winding of the insulating member 13 is attached to the insulating surface 1121, and the projection of the starting end of the winding of the insulating member 13 does not overlap with the projection of the first negative electrode straight portion 121a along the thickness direction of the electrode assembly 11a.

[0169] That is, the portion of the starting end of the separator 13 that extends beyond the starting end of the first negative electrode straight portion 121a can be wound and bent and then accommodated in the bending space of the first bending portion 112a.

[0170] Furthermore, in this embodiment, as Figure 6 As shown, with the dashed line L as the dividing line, the starting end of the winding of the isolator 13 is located on one side of the dashed line L, and the first negative electrode straight portion 121a is located on the other side of the dashed line L. The projections of the two along the thickness direction of the electrode assembly 11a do not overlap. The starting end of the winding of the isolator 13 can extend towards the first positive electrode straight portion 111a, making the length of the portion of the isolator 13 extending beyond the first negative electrode straight portion 121a longer, further improving the reliability of the electrical isolation of the isolator 13. Furthermore, the projection of the starting end of the winding of the isolator 13 does not overlap with the projection of the first negative electrode straight portion 121a, meaning that only one layer of isolator 13 is still provided between the first positive electrode straight portion 111a and the first negative electrode straight portion 121a. The starting end of the winding of the isolator 13 does not extend between the first positive electrode straight portion 111a and the first negative electrode straight portion 121a, thus avoiding wasted space.

[0171] In a specific embodiment, it can be understood that when manufacturing the electrode assembly 11a, an adsorption-type winding needle 30 can be used for winding, i.e., the winding needle 30 can be wound using a vacuum adsorption isolation member 13 on its surface, such as... Figure 11 As shown; alternatively, the positive electrode 11 or negative electrode 12 can be first bonded to the separator 13, and then the separator 13 and the bonded positive electrode 11 or negative electrode 12 can be wound up using a clamping winding needle 30, as shown. Figure 12 As shown, in this way, an electrode assembly 11a with only one layer of insulating material 13 in the innermost ring can be obtained.

[0172] In other embodiments, unlike the embodiments described above, such as Figure 5 , Figures 7 to 9 As shown, the positive electrode 11 is a single piece (i.e., the positive electrode 11 does not include the first connector 116), and it is not cut at the first bend 112a.

[0173] In this embodiment, the electrode assembly 11a further includes a first insulating member 114, which is attached to the surface of the first bent portion 112a facing the center of the electrode assembly 11a, and the surface of the first insulating member 114 facing the center of the electrode assembly 11a forms an insulating surface 1121.

[0174] In this embodiment, a first insulating member 114 is attached to a portion of the surface of the positive electrode 11. After the first insulating member 114 is attached to the surface of the positive electrode 11, it is wound together with the positive electrode 11. After being wound, the first insulating member 114 is located on the inner surface of the first bending portion 112a of the positive electrode 11, facing the center of the electrode assembly 11a, thereby blocking the positive active material on the inner surface of the first bending portion 112a of the positive electrode 11, so that the surface of the first bending portion 112a of the positive electrode 11 forms an insulating surface 1121.

[0175] In this embodiment, by attaching a first insulating member 114 to the corresponding position of the positive electrode 11, and extending the opposite ends of the first insulating member 114 along the winding direction of the electrode assembly 11a to overlap with the end of the first negative electrode straight portion 121a located in the innermost ring of the electrode assembly 11a, the first insulating member 114 can isolate the positive electrode active material at the corresponding position of the positive electrode 11, so that the negative electrode active material at the inner ring position of the electrode assembly 11a meets the requirements of over-design. Thus, the method of setting the first insulating member 114 to isolate the positive electrode active material is simple, and the method of setting the insulating surface 1121 has little impact on the molding process of the electrode assembly 11a. Before winding the positive electrode 11, the first insulating member 114 can be attached to the surface of the positive electrode 11 at a preset position. Production can be carried out by appropriately adjusting the existing molding process, which has good practicality and versatility.

[0176] In a specific embodiment, the first insulating element 114 is a polyethylene terephthalate film, a polyimide film, or a polypropylene film.

[0177] Understandably, polyethylene terephthalate film, polyimide film or polypropylene film are all high molecular weight ion barrier materials. When applied to the surface of the positive electrode 11, they do not provide ion channels and can block the ion pathway of the positive electrode active material at the corresponding position of the positive electrode 11.

[0178] For example, the first insulating element 114 can be adhesive tape, which is attached to the surface of the positive electrode 11 to block the transmission path of the positive electrode active material. The surface of the adhesive tape facing away from the positive electrode 11 is the insulating surface 1121.

[0179] In this embodiment, as Figure 8 and Figure 9 As shown, the thickness of the first insulating element 114 is 0.003mm to 2mm.

[0180] In this embodiment, as Figure 9 As shown, the thickness D1 of the first insulating member 114 refers to the protrusion height of the first insulating member 114 from the surface of the positive electrode 11. In the electrode assembly 11a, this protrusion height will affect the volume of the electrode assembly 11a. Thus, by setting the thickness of the first insulating member 114 within the above-mentioned thickness range, the first insulating member 114 can play the role of ion blocking, while not occupying too much space, and the energy density of the electrode assembly 11a will not be greatly reduced due to the setting of the first insulating member 114.

[0181] In a specific embodiment, the thickness of the first insulating element 114 can be 0.003mm, 0.01mm, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, or 2mm, etc. The specific thickness value is not uniquely limited here, and can be selected as needed during design.

[0182] In a specific embodiment, such as Figure 5 , Figure 9 and Figure 10 As shown, the electrode assembly 11a in the above embodiment can be manufactured using the following manufacturing method. Specifically, the method includes:

[0183] Step S100: Provide the insulating component 13, the negative electrode material receiving assembly, and the positive electrode material receiving assembly; wherein, the positive electrode material receiving assembly includes a positive electrode sheet 11 and a first insulating component 114, and the negative electrode material receiving assembly includes a negative electrode sheet 12;

[0184] Step S200: The first insulating member 114 is attached to a preset position near the starting end of the positive electrode plate 11;

[0185] Step S300: The separator, the negative electrode 12 and the positive electrode 11 with the first insulating element 114 attached are fed into the winding mechanism to form a wound body;

[0186] Step S400: The wound body is shaped to obtain an electrode assembly 11a with a flat structure; wherein, the electrode assembly 11a has a flat region 14 and bending regions 15 located at opposite ends of the flat region 14, the positive electrode 11 includes a plurality of positive electrode flat portions 111 disposed in the flat region 14, and the negative electrode 12 includes a plurality of negative electrode flat portions 121 disposed in the flat region 14. Along the direction perpendicular to the flat region 14, the plurality of positive electrode flat portions 111 and the plurality of negative electrode flat portions 121 are staggered and stacked. The positive electrode 11 also includes a plurality of positive electrode bending portions 112 disposed in the bending region 15. The positive electrode straight portion 111 is connected to the end of each positive electrode bending portion 112. The first insulating member 114 is attached to the inner surface of the first bending portion 112a located in the inner ring of the electrode assembly 11a. Furthermore, along the winding direction of the electrode assembly 11a, the two opposite ends of the first insulating member 114 extend to the straight region 14 and overlap with the end of the first negative electrode straight portion 121a located in the innermost ring of the electrode assembly 11a.

[0187] In step S100, the separator 13, the negative electrode feeding assembly, and the positive electrode feeding assembly can be fed separately; for example, the positive electrode sheet 11 and the first insulating member 114 in the separator 13, the negative electrode feeding assembly, and the positive electrode feeding assembly can be unwound by the unwinding mechanism to achieve separate feeding.

[0188] The positive electrode assembly includes a positive electrode sheet 11 and a first insulating member 114. The positive electrode sheet 11 refers to a strip-shaped electrode structure coated with positive active material on both sides of a positive electrode current collector substrate. The positive electrode sheet 11 can be wound into multiple turns by a winding mechanism to form part of the electrode assembly 11a. The first insulating member 114 is one of polyethylene terephthalate film, polyimide film, or polypropylene film. The first insulating member 114 has a sheet-like structure. It should be understood that the length of the first insulating member 114 is shorter than the length of the positive electrode sheet 11. That is, when the positive electrode sheet 11 is wound into the winding body, the middle part of the first insulating member 114 is located on the inner surface of the first bend 112a, and the opposite ends extend to the straight area 14 and overlap with the end of the first negative electrode straight portion 121a. The first insulating member 114 will not cover other positions of the positive electrode sheet 11. In the specific production process, this is achieved by controlling the length of the first insulating member 114 and its relative length with the positive electrode sheet 11.

[0189] The negative electrode assembly includes a negative electrode sheet 12, which refers to an electrode structure on which a negative electrode active material is coated on both sides of a negative electrode current collector substrate; the negative electrode sheet 12 can be wound into multiple turns by a winding mechanism to form part of the electrode assembly 11a.

[0190] The separator 13 is used to separate the negative electrode feed assembly and the positive electrode feed assembly. Simultaneously, the separator 13 can form an ion channel between the negative electrode feed assembly and the positive electrode feed assembly, ensuring the transfer and reaction of positive and negative ions. Optionally, the separator 13 can be a separator membrane, etc., and its material can be polypropylene or polyethylene, etc.

[0191] In step S300, the winding mechanism refers to the structure used to wind the positive electrode material assembly, the separator 13, and the negative electrode material assembly. The winding mechanism may include a winding needle for fixing the positive electrode material assembly, the separator, and the negative electrode material assembly, and may also include a pressing member, an adhesive applicator, a feeding member, etc., for finishing processing.

[0192] In actual production, the positive electrode material assembly, the separator 13 and the negative electrode material assembly can be fed into the winding mechanism and wound separately; or, the positive electrode material assembly, the separator 13 and the negative electrode material assembly can be rolled and compounded before being fed into the winding mechanism and wound.

[0193] The electrode assembly 11a manufactured using the manufacturing method of this embodiment has a plurality of negative electrode straight portions 121 and a plurality of positive electrode straight portions 111 arranged in an alternating stack in the straight region 14. At each position in the straight region 14 of the electrode assembly 11a, the positive electrode straight portion 111 is always aligned with the negative electrode straight portion 121, thus satisfying the requirement that the positive electrode active material is aligned with the negative electrode active material. This allows for full utilization of the inner space of the electrode assembly 11a to accommodate the active material for reaction and current generation, thereby increasing the energy density of the electrode assembly 11a and the battery cell 10. Furthermore, a first insulating member 114 is attached to a predetermined position on the positive electrode sheet 11, and the positive electrode sheet 11 with the attached first insulating member 114 is then wound together with the separator 13 and the negative electrode sheet 12 to form the electrode assembly 11a. This results in the first bent portion 112a at the starting end of the electrode assembly 11a having an insulating surface 1121 disposed towards the center of the electrode assembly 11a. Both ends of the insulating surface 1121 extend to the straight region 14 and overlap with the ends of the first negative electrode straight portion 121a. The insulating surface 1121 does not provide positive electrode active material to participate in the chemical reaction. Thus, in the bent region 15 of the electrode assembly 11a, there will be no situation of excessive or insufficient negative electrode active material due to positive electrode active material facing positive electrode active material. This can meet the over-design requirements of the electrode assembly 11a for negative electrode capacity, reduce the risk of lithium plating of the electrode assembly 11a, and improve the energy density of the battery cell 10 while ensuring the stability and reliability of the electrical performance of the battery cell 10, thereby improving the overall performance of the battery cell 10.

[0194] In a specific embodiment, such as Figures 13 to 15As shown, the positive electrode 11 may further include a second insulating member 115. Along the winding direction of the electrode assembly 11a, the second insulating member 115 is spaced apart from the first insulating member 114. The plurality of positive electrode straight portions 111 also include a plurality of third positive electrode straight portions 111c spaced apart along the winding direction of the positive electrode 11. The plurality of positive electrode bent portions 112 also include a second bent portion 112b and at least one third bent portion 112c. A third positive electrode straight portion 111c is connected to the second positive electrode straight portion 111b through the second bent portion 112b. Two third positive electrode straight portions 111c arranged adjacent to each other along the winding direction are connected through a third bent portion 112c. The second insulating member 115 is attached to the surface of at least the second bent portion 112b facing the center of the electrode assembly 11a.

[0195] In this embodiment, the plurality of straight positive electrode portions 111 of the positive electrode sheet 11 further include a plurality of third straight positive electrode portions 111c, and the plurality of bent positive electrode portions 112 further include a second bent portion 112b and at least one third bent portion 112c. The third straight positive electrode portion 111c refers to the third to nth straight positive electrode portion of the positive electrode sheet 11 located downstream of the second straight positive electrode portion 111b, which is formed by winding the portion through a winding mechanism and shaping and pressing it through a shaping operation. The positive electrode sheet 11 is connected to... The portion between the second positive electrode straight portion 111b and the adjacent first third positive electrode straight portion 111c is the second bent portion 112b, and the portion connecting the two adjacent third positive electrode straight portions 111c is the third bent portion 112c. When there are two third positive electrode straight portions 111c, there is one third bent portion 112c. When there are three or more third positive electrode straight portions 111c, there are two or more third bent portions 112c.

[0196] In this embodiment, in addition to the first insulating member 114 being attached to the surface of the first bent portion 112a facing the electrode assembly 11a, a second insulating member 115 is attached to the inner surface of the second bent portion 112b, which is at least located behind the first bent portion 112a, along the winding direction of the electrode assembly 11a. In this way, at least the positive electrode active material on the inner surface of the second bent portion 112b facing the electrode assembly 11a can be partially or completely blocked by the second insulating member 115, thereby reducing the amount of positive electrode active material participating in the electrochemical reaction at that location.

[0197] In related technologies, in a wound electrode assembly 11a, along the direction from the inner ring to the outer ring of the electrode assembly 11a, at the position of the bending region 15, there is a situation where the inner surface of the positive electrode bending portion 112 is directly opposite the outer surface of the negative electrode bending portion 122. The closer to the winding center of the electrode assembly 11a, the greater the curvature of the bending position. At the position with greater curvature, there may be a situation where the amount of positive electrode active material is greater than the amount of negative electrode active material.

[0198] Based on this, in this embodiment, a second insulating member 115 is attached to the inner surface of the second bent portion 112b of the positive electrode sheet 11. The second bent portion 112b is the bent portion with the largest curvature among the multiple positive electrode bent portions 112 except for the first bent portion 112a. The second insulating member 115 is attached to at least the inner surface of the bent portion. The second insulating member 115 can block at least part of the positive electrode active material disposed at the bent portion, thereby making the amount of negative electrode active material in the electrode assembly 11a at this position greater than that of the positive electrode active material, so as to meet the design requirement of excess negative electrode active material.

[0199] In a specific embodiment, the electrode assembly 11a may include a second insulating member 115, which is attached to the inner surface of the second bent portion 112b of the positive electrode sheet 11.

[0200] Alternatively, in other embodiments, the electrode assembly 11a includes a plurality of second insulating members 115, which are arranged sequentially and at intervals along the winding direction of the electrode assembly 11a. The second insulating member 115 is attached to the surface of the second bend 112b facing the center of the electrode assembly 11a, and the second insulating member 115 is attached to the surface of at least the first third bend 112c adjacent to the second bend 112b facing the center of the electrode assembly 11a.

[0201] As an example, electrode assembly 11a includes two second insulating members 115, which are arranged continuously at intervals. One second insulating member 115 is attached to the inner surface of the second bend 112b, and the other second insulating member 115 is attached to the inner surface of the first third bend 112c adjacent to the second bend 112b; or, electrode assembly 11a includes three or more second insulating members 115, one of which is attached to the inner surface of the second bend 112b. On the surface, a second insulating member 115 is attached to the inner surface of the first third bend 112c adjacent to the second bend 112b, and the remaining one or more second insulating members 115 are attached to the inner surface of the subsequent one or more third bends 112c in a corresponding manner. For example, multiple second insulating members 115 are attached to the inner surfaces of the second third bend 112c, the third third bend 112c, the fourth third bend 112c and each subsequent third bend 112c.

[0202] Thus, a second insulating member 115 is attached to the inner surface of the second bend 112b and one or more third bends 112c located in the inner ring of the positive electrode sheet 11. That is, the second insulating member 115 is attached to the inner surface of the multiple positive electrode bends 112 located in the inner ring of the positive electrode sheet 11 and the electrode assembly 11a. At the position of large curvature in the inner ring of the electrode assembly 11a, by setting the second insulating member 115 to cover part of the positive electrode active material on the inner surface of the positive electrode bend 112, the electrode assembly 11a can meet the design requirements of excessive negative electrode active material at the positions with large curvature.

[0203] In the above embodiments, it can be understood that the second insulating member 115 and the first insulating member 114 being spaced apart means that when the electrode assembly 11a includes one second insulating member 115, along the winding direction of the electrode assembly 11a, the second insulating member 115 is spaced downstream of the first insulating member 114, and the starting end of the second insulating member 115 along the winding direction is spaced apart from the ending end of the first insulating member 114 along the winding direction; or, when the electrode assembly 11a includes multiple second insulating members 115, along the winding direction of the electrode assembly 11a, the multiple second insulating members 115 are continuously spaced apart, wherein the starting end of the first second insulating member 115 located at the starting end along the winding direction is spaced apart from the ending end of the first insulating member 114.

[0204] In the above embodiments, the second insulating member 115 is attached to the surface of the second bent portion 112b facing the center of the electrode assembly 11a, meaning that part or all of the inner surface of the second bent portion 112b facing the center of the electrode assembly 11a is covered by the second insulating member 115, so that part or all of the positive electrode active material located on the inner surface of the second bent portion 112b is blocked by the second insulating member 115. Similarly, the second insulating member 115 is attached to the surface of the third bent portion 112c facing the center of the electrode assembly 11a, meaning that part or all of the inner surface of the third bent portion 112c facing the center of the electrode assembly 11a is covered by the second insulating member 115, so that part or all of the positive electrode active material located on the inner surface of the third bent portion 112c is blocked by the second insulating member 115.

[0205] In the above embodiments, the second insulating element 115 is a polyethylene terephthalate film, a polyimide film, or a polypropylene film.

[0206] Understandably, polyethylene terephthalate film, polyimide film or polypropylene film are all high molecular weight ion barrier materials. When applied to the surface of the positive electrode 11, they do not provide ion channels and can block the ion pathway of the positive electrode active material on the positive electrode 11.

[0207] For example, the second insulating element 115 can also be adhesive tape, which is attached to the surface of the positive electrode 11 to block the transport path of the positive electrode active material.

[0208] It should be noted that, in specific embodiments, the first insulating member 114 may be made of the same material as the second insulating member 115, or the first insulating member 114 may be made of a different material than the second insulating member 115.

[0209] In a specific embodiment, such as Figure 13 and 15 As shown, the thickness of the second insulating element 115 can also be 0.003mm to 2mm.

[0210] In this embodiment, as Figure 15 As shown, the thickness D2 of the second insulating member 115 refers to the protrusion height of the second insulating member 115 from the surface of the positive electrode 11. In the electrode assembly 11a, this protrusion height will affect the volume of the electrode assembly 11a. Thus, by setting the thickness of the second insulating member 115 within the above-mentioned thickness range, the second insulating member 115 can play the role of ion blocking, while not occupying too much space, and the energy density of the electrode assembly 11a will not be greatly reduced due to the setting of the second insulating member 115.

[0211] In a specific embodiment, the thickness of the second insulating element 115 can be 0.003mm, 0.01mm, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, or 2mm, etc. The specific thickness value is not uniquely limited here, and can be selected according to the needs during design.

[0212] In a specific embodiment, such as Figure 13 , Figure 15 and Figure 16 As shown, taking electrode assembly 11a including a second insulating member 115 as an example, the electrode assembly 11a in the above embodiment can be manufactured using the following manufacturing method. Specifically, the method includes:

[0213] Step S100a: Provide the insulating component 13, the negative electrode material receiving assembly, and the positive electrode material receiving assembly; wherein, the positive electrode material receiving assembly includes a positive electrode sheet 11, a first insulating component 114, and a second insulating component 115, and the negative electrode material receiving assembly includes a negative electrode sheet 12;

[0214] Step S200a: The first insulating member 114 is attached to a preset position near the starting end of the positive electrode plate 11, and the second insulating member 115 is attached to a preset position near the first insulating member 114 of the positive electrode plate 11, wherein the first insulating member 114 and the second insulating member 115 are spaced apart.

[0215] Step S300a: The separator, the negative electrode 12 and the positive electrode 11 with the first insulating element 114 and the second insulating element 115 attached are fed into the winding mechanism to be wound to form a wound body;

[0216] Step S400a: The wound body is shaped to obtain an electrode assembly 11a with a flat structure; wherein, the electrode assembly 11a has a flat region 14 and bending regions 15 located at opposite ends of the flat region 14, the positive electrode 11 includes a plurality of positive electrode flat portions 111 disposed in the flat region 14, the negative electrode 12 includes a plurality of negative electrode flat portions 121 disposed in the flat region 14, and along the thickness direction of the electrode assembly 11a, the plurality of positive electrode flat portions 111 and the plurality of negative electrode flat portions 121 are staggered and stacked, and the positive electrode 11 also includes a plurality of positive electrode bending portions 121 disposed in the bending regions 15. 12. The straight positive electrode portion 111 is connected to the end of each positive electrode bent portion 112. The first insulating member 114 is attached to the inner surface of the first bent portion 112a located in the inner ring of the electrode assembly 11a. Along the winding direction of the electrode assembly 11a, the two opposite ends of the first insulating member 114 extend to overlap with the end of the first negative electrode straight portion 121a located in the innermost ring of the electrode assembly 11a. The second insulating member 115 is attached to the inner surface of the second bent portion 112b located in the inner ring of the electrode assembly 11a. The second insulating member 115 is at least partially located in the bent area 15.

[0217] In this manufacturing method, unlike the aforementioned manufacturing method, in step S200a, after the first insulating member 114 is attached to a preset position near the starting end of the positive electrode plate 11, a second insulating member 115 is also attached to a preset position near the first insulating member 114 on the positive electrode plate 11. The other steps are basically the same as those in the above embodiments and will not be repeated here.

[0218] In some embodiments of this application, such as Figures 17 to 19 As shown, the first connector 116 is a flexible connector. In this way, by using the flexible first connector 116 to replace the electrode body 113 in bending deformation within the bending area 15, the probability of the positive electrode 11 breaking in the bending area 15 can be reduced, thereby reducing the probability of the positive electrode 11 brittlely breaking and puncturing the separator 13, and further improving the electrical reliability of the electrode assembly 11a and the battery cell 10.

[0219] Understandably, the first connector 116 being a flexible connector means that the first connector 116 is a connector that is easy to bend, deformable and not easy to break. Its stiffness is less than that of the electrode body 113, and its hardness is also less than that of the electrode body 113, so that the first connector 116 is easier to bend and deform than the electrode body 113.

[0220] In a specific embodiment, the first connector 116 can be a polyethylene terephthalate (PET) component, a polyimide component, or a polypropylene component. PET, polyimide, or polypropylene are all high-molecular-weight ion-barrier materials. When a connector made from these materials is used to connect the first electrode portion 1131 and the second electrode portion 1132, it does not provide positive electrode active material for electrochemical reactions, while simultaneously possessing higher flexibility, reducing the probability of breakage of the positive electrode 11 through bending and deformation.

[0221] For example, the first connector 116 can be adhesive tape, with one end of the adhesive tape applied to the end of the first electrode portion 1131 and the other end applied to the end of the second electrode portion 1132, thereby connecting the first electrode portion 1131 and the second electrode portion 1132. The surface of the adhesive tape facing the center of the electrode assembly 11a is the insulating surface 1121.

[0222] In this embodiment, a portion of the first connector 116 is located within the bending area 15, that is, the middle portion of the first connector 116 is located within the bending area 15. The opposite ends of the first connector 116 extend into the straight area 14 and are connected to the corresponding first electrode portion 1131 and second electrode portion 1132, so that the end of the first connector 116 can overlap with the end of the first negative electrode straight portion 121a of the innermost ring of the electrode assembly 11a, that is, the end of the insulating surface 1121 of the first connector 116 can overlap with the end of the first negative electrode straight portion 121a.

[0223] In some embodiments, such as Figure 19 and Figure 20 As shown, one end of the first connector 116 is attached to the surface of the first electrode portion 1131, and the other end of the first connector 116 is attached to the surface of the second electrode portion 1132.

[0224] That is, the first connector 116 covers the surface of the end of the first electrode portion 1131 and the surface of the end of the second electrode portion 1132. In this way, the first connector 116 can also cover and protect the cut positions of the first electrode portion 1131 and the second electrode portion 1132, so as to cover and block the burrs at the cut formed by cutting, reduce the probability of burrs piercing the isolator 13 and causing short circuit, and improve the electrical reliability of the electrode assembly 11a.

[0225] In some embodiments, such as Figure 17 , Figure 18 and Figure 20 As shown, the first connector 116 includes a first sub-part 1161 and a second sub-part 1162. One end of the first sub-part 1161 is attached to the surface of the first electrode portion 1131 facing the center of the electrode assembly 11a, and the other end is attached to the surface of the second electrode portion 1132 facing the center of the electrode assembly 11a. One end of the second sub-part 1162 is attached to the surface of the first electrode portion 1131 facing away from the center of the electrode assembly 11a, and the other end is attached to the surface of the second electrode portion 1132 facing away from the center of the electrode assembly 11a.

[0226] In this embodiment, the first connector 116 connects the first electrode portion 1131 and the second electrode portion 1132 to opposite sides of the electrode body 113 along the thickness direction. In this way, the first sub-part 1161 of the first connector 116 covers the burrs on the inner surface of the cut-out facing the center of the electrode assembly 11a, and the second sub-part 1162 covers the burrs on the outer surface of the cut-out facing away from the center of the electrode assembly 11a. This further reduces the probability of burrs piercing the isolator 13 and causing a short circuit, thereby improving the electrical reliability of the electrode assembly 11a.

[0227] Of course, it is understood that in other embodiments, a first connector 116 may be provided on either side of the electrode body 113 along the thickness direction to connect the first electrode portion 1131 and the second electrode portion 1132.

[0228] In some embodiments, such as Figure 20 As shown, the protrusion thickness of the first sub-part 1161 and the second sub-part 1162 from the corresponding first electrode part 1131 or second electrode part 1132 is 0.003mm to 2mm.

[0229] That is, in a specific embodiment, the protrusion thickness D3 of the first sub-part 1161 from the first electrode part 1131 is 0.003mm to 2mm, the protrusion thickness D4 of the second sub-part 1162 from the first electrode part 1131 is 0.003mm to 2mm, the protrusion thickness of the first sub-part 1161 from the second electrode part 1132 is 0.003mm to 2mm, and the protrusion thickness of the second sub-part 1162 from the second electrode part 1132 is 0.003mm to 2mm. Thus, the protrusion thickness of the first sub-part 1161 and the protrusion thickness of the second sub-part 1162 are the protrusion heights of the first sub-part 1161 or the second sub-part 1162 from the surface of the corresponding first electrode portion 1131 or the surface of the second electrode portion 1132. This protrusion height affects the winding volume of the electrode assembly 11a. By setting the protrusion thickness of the first sub-part 1161 and the protrusion thickness of the second sub-part 1162 within the aforementioned thickness range, the first connector 116 can both connect the first electrode portion 1131 and the second electrode portion 1132 and the ion barrier, while not occupying too much space, and the energy density of the electrode assembly 11a will not be significantly reduced due to the setting of the first connector 116.

[0230] In a specific embodiment, the protrusion thickness of the first sub-part 1161 from the first electrode portion 1131 can be 0.003mm, 0.01mm, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, or 2mm, etc., and the protrusion thickness of the second sub-part 1162 from the first electrode portion 1131 can be 0.003mm, 0.01mm, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, or 2mm, etc., and the protrusion thickness of the first sub-part 1161 from the second electrode portion... The protrusion thickness of 1132 can be 0.003mm, 0.01mm, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, or 2mm, etc., and the protrusion thickness of the second sub-part 1162 from the second electrode part 1132 can be 0.003mm, 0.01mm, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, or 2mm, etc. The specific thickness value of each sub-part is not uniquely limited here, and can be selected according to the needs during design.

[0231] In some embodiments, such as Figure 17 , Figure 20 and Figure 21 As shown, the positive electrode 11 includes a first electrode portion 1131, a first connector 116, and a second electrode portion 1132. The electrode assembly 11a in the above embodiment can be manufactured using the following method for manufacturing the electrode assembly 11a. Specifically, the method includes:

[0232] Step S100b: Provide an insulating component 13, a negative electrode material receiving assembly, and a positive electrode material receiving assembly, wherein the negative electrode material receiving assembly includes a negative electrode sheet 12, and the positive electrode material receiving assembly includes an electrode sheet body 113 and a first connector 116, the first connector 116 being an insulating component;

[0233] Step S200b: Cut the electrode body 113 to form a first electrode portion 1131 and a second electrode portion 1132;

[0234] Step S300b: Cover the first connector 116 on the corresponding cut-off part of the electrode body 113, and connect it with the cut-off first electrode part 1131 and second electrode part 1132 to form an integral positive electrode 11;

[0235] Step S400b: The separator 13, the negative electrode 12 and the positive electrode 11 are fed into the winding mechanism to be wound to form a wound body;

[0236] Step S500b: The wound body is shaped to obtain an electrode assembly 11a with a flat structure; wherein, the electrode assembly 11a has a flat region 14 and bending regions 15 located at opposite ends of the flat region 14, the positive electrode 11 includes a plurality of positive electrode flat portions 111 disposed in the flat region 14, the negative electrode 12 includes a plurality of negative electrode flat portions 121 disposed in the flat region 14, and along the thickness direction perpendicular to the electrode assembly 11a, the plurality of positive electrode flat portions 111 and the plurality of negative electrode flat portions 121 are staggered and stacked, and the positive electrode 11 also includes a plurality of bending regions 111 and 121 disposed in the bending regions 111 and 121. The positive electrode bending portion 112 of 5 has a positive electrode straight portion 111 connected to the end of each positive electrode bending portion 112. Along the winding direction, the second electrode portion 1132 and the first electrode portion 1131 are arranged at intervals. The first electrode portion 1131 is continuously wound along the winding direction. The first positive electrode straight portion 111a is located in the second electrode portion 1132, and the second positive electrode straight portion 111b is located in the first electrode portion 1131. The first connector 116 connects the first electrode portion 1131 and the second electrode portion 1132 along the winding direction. The first bending portion 112a is provided on the first connector 116.

[0237] In step S100b, the separator 13, the negative electrode feeding assembly, and the positive electrode feeding assembly can be fed separately; for example, the electrode body 113 and the first connector 116 in the separator 13, the negative electrode feeding assembly, and the positive electrode feeding assembly can be unwound by the unwinding mechanism to achieve separate feeding.

[0238] The positive electrode assembly includes an electrode body 113 and a first connector 116. The electrode body 113 refers to a strip-shaped electrode structure coated with positive electrode active material on both sides of the positive electrode current collector substrate. The electrode body 113 can be wound into multiple turns by a winding mechanism to form part of the electrode assembly 11a. The first connector 116 can be one of polyethylene terephthalate, polyimide, or polypropylene. The first connector 116 has a sheet-like structure. It should be understood that the length of the first connector 116 is shorter than the length of the electrode body 113. That is, when the electrode body 113 is wound into the winding body, the middle part of the first connector 116 is located on the inner surface of the first bend 112a, and the opposite two ends extend to the straight area 14 and overlap with the end of the first negative electrode straight portion 121a. The first connector 116 does not cover the other surfaces of the electrode body 113.

[0239] The negative electrode assembly includes a negative electrode sheet 12, which refers to an electrode structure on which a negative electrode active material is coated on both sides of a negative electrode current collector substrate; the negative electrode sheet 12 can be wound into multiple turns by a winding mechanism to form part of the electrode assembly 11a.

[0240] The separator 13 is used to separate the negative electrode feed assembly and the positive electrode feed assembly. Simultaneously, the separator 13 can form an ion channel between the negative electrode feed assembly and the positive electrode feed assembly, ensuring the transfer and reaction of positive and negative ions. Optionally, the separator 13 can be a separator membrane, etc., and its material can be polypropylene or polyethylene, etc.

[0241] In step S200b, the electrode body 113 is cut to form a first electrode portion 1131 and a second electrode portion 1132. The electrode body 113 can be cut by a cutting process to form a longer first electrode portion 1131 and a shorter second electrode portion 1132.

[0242] In step S300b, one end of the first connector 116 is connected to the end of the first electrode portion 1131 near the second electrode portion 1132, and the other end of the first connector 116 is connected to the end of the second electrode portion 1132 near the first electrode portion 1131. This allows the first connector 116 to cover the corresponding cut-off point of the electrode body 113. In other words, the first connector 116 can be positioned at the corresponding cut-off point and simultaneously connected to the first electrode portion 1131 and the second electrode portion 1132 formed after the cut-off portion to form a long strip-shaped positive electrode 11. By setting the first connector 116 to reconnect the first electrode portion 1131 and the second electrode portion 1132 formed after the cut-off portion to form a single unit, the integrated structure is less prone to detachment or loosening during transmission and winding. Furthermore, it can be fed using the same feeding mechanism, effectively improving the production efficiency and quality of the electrode assembly 11a.

[0243] In step S400b, the winding mechanism refers to the structure used to wind the positive electrode material assembly, the separator 13, and the negative electrode material assembly. The winding mechanism may include a winding needle 30 for fixing the positive electrode material assembly, the separator, and the negative electrode material assembly, and may also include a pressing member, an adhesive applicator, a feeding member, etc., for finishing processing.

[0244] In actual production, the positive electrode material assembly, the separator 13 and the negative electrode material assembly can be fed into the winding mechanism and wound separately; or, the positive electrode material assembly, the separator 13 and the negative electrode material assembly can be rolled and compounded before being fed into the winding mechanism and wound.

[0245] In step S500b, the negative electrode sheet 12 forms multiple negative electrode straight portions 121 in the flat region 14. That is, after the negative electrode sheet 12 is wound multiple times by the winding mechanism and pressed into a flat shape by the shaping operation, each turn of the negative electrode sheet 12 forms multiple flat negative electrode straight portions 121 in the flat region 14. The first negative electrode straight portion 121a among the multiple negative electrode straight portions 121 refers to the first negative electrode straight portion formed by the winding starting end of the negative electrode sheet 12 being wound on the innermost turn by the winding mechanism and shaped and pressed by the shaping operation. The positive electrode 11 forms multiple positive electrode straight portions 111 in the flat region 14. That is, after the positive electrode 11 is wound multiple times by a winding mechanism and pressed into a flat shape by a shaping operation, each turn of the positive electrode 11 forms multiple straight positive electrode straight portions 111 in the flat region 14. The multiple positive electrode straight portions 111 and multiple negative electrode straight portions 121 are arranged alternately in the flat region 14. The positive electrode 11 also includes positive electrode bent portions 112. That is, the positive electrode 11 forms multiple positive electrode bent portions 112 in the bent region 15. After the positive electrode 11 is wound multiple times by a winding mechanism and pressed into a flat shape by a shaping operation, each turn of the positive electrode 11 forms multiple bent positive electrode bent portions 112 in the bent region 15. The first bending portion 112a among the multiple positive electrode bending portions 112 refers to the first positive electrode bending portion formed by the winding start end of the positive electrode sheet 11 being wound around the innermost circle by a winding mechanism and shaped and pressed by a shaping operation.

[0246] The positive electrode 11 includes an electrode body 113 and a first connector 116. The electrode body 113 includes a first electrode portion 1131 and a second electrode portion 1132 spaced apart along the winding direction. The first connector 116 connects the first electrode portion 1131 and the second electrode portion 1132. In the wound electrode assembly 11a, the first electrode portion 1131 is continuously wound along the winding direction, and the second electrode portion 1132 is spaced apart upstream of the first electrode portion 1131 along the winding direction. The first connector 116 connects the end of the second electrode portion 1132 and the beginning of the first electrode portion 1131 along the winding direction, thereby connecting the first electrode portion 1131 and the second electrode portion 1132 into a single positive electrode 11 with a strip-like structure. Furthermore, after the positive electrode 11 is wound, a portion of the first connector 116 is located within the bending area 15. The opposite ends of the first connector 116 extend into the straight area 14 to connect the first electrode portion 1131 and the second electrode portion 1132. The first positive electrode bending portion of the positive electrode 11 is provided on the first connector 116, and the insulating surface 1121 is provided on the surface of the first connector 116 facing the center of the electrode assembly 11a.

[0247] Thus, the electrode assembly 11a manufactured using the above-described manufacturing method, by setting a first connector 116 to replace part of the electrode body 113 within the bending area 15, and by bending and deforming the first connector 116 to replace part of the electrode body 113, after the electrode body 113 is broken into a first electrode portion 1131 and a second electrode portion 1132, the first connector 116 is then applied to the broken position of the electrode body 113 and the first electrode portion 1131 and the second electrode portion 1132 are connected to form an integral positive electrode 11. The first connector 116 can be set as an insulating component to meet the design requirements of excessive negative electrode active material. Furthermore, the first connector 116 can also be a flexible connector. By using the flexible first connector 116 to replace the electrode body 113 in bending deformation within the bending area 15, the probability of the positive electrode 11 breaking in the bending area 15 can be reduced, thereby reducing the probability of the positive electrode 11 brittlely breaking and puncturing the separator 13, further improving the electrical reliability of the electrode assembly 11a and the battery cell 10. In addition, by connecting the cut first electrode portion 1131 and the second electrode portion 1132 through the first connector 116, the positive electrode 11 forms an integral strip structure. The positive electrode 11 can still be fed through the same feeding mechanism during the winding process, simplifying the feeding process and improving production efficiency.

[0248] In other embodiments, such as Figures 22 to 24 As shown, based on the above embodiment, the positive electrode 11 further includes at least one second connector 117. The first electrode portion 1131 includes a first electrode segment 11311 and at least one second electrode segment 11312. Along the winding direction of the electrode assembly 11a, the second electrode portion 1132 and the first electrode segment 11311 are arranged at intervals, and the second electrode segments 11312 are arranged at intervals between the second electrode portion 1132 and the first electrode segment 11311. The first electrode segment 11311 is continuously wound. The first connector 116 connects the second electrode portion 1132 and the adjacent second electrode segment 11312. The second connector 117 connects two adjacent second electrode segments 11312, and / or, the second connector 117 connects the adjacent second electrode segments 11312 and the first electrode segment 11311. The second connector 117 is an insulating member.

[0249] In this embodiment, the first electrode portion 1131 includes a first electrode segment 11311 and at least one second electrode segment 11312. Along the winding direction, the second electrode portion 1132, the second electrode segment 11312, and the first electrode segment 11311 are arranged sequentially at intervals. The second connector 117 connects two adjacent second electrode segments 11312 and / or connects adjacent second electrode segments 11312 and first electrode segments 11311. That is, the number of second electrode segments 11312 can be one or more. When the number of second electrode segments 11312 is one, the first electrode portion 1131 includes a first electrode segment 11311 and a second electrode segment 11312. The first connector 116 connects the second electrode portion 1132 and the second electrode segment 11312, and the second connector 117 connects the second electrode segment 11312 and the first electrode segment 11311, resulting in a [missing information - likely a specific shape or shape]. A continuous strip-shaped positive electrode 11; when there are multiple second electrode segments 11312, the first electrode portion 1131 includes a first electrode segment 11311 and multiple second electrode segments 11312. A first connector 116 connects the second electrode portion 1132 and an adjacent second electrode segment 11312. Two adjacent second electrode segments 11312 are connected by a second connector 117. The first electrode segment 11311 and an adjacent second electrode segment 11312 are also connected by a second connector 117, thereby obtaining a continuous strip-shaped positive electrode 11. When the positive electrode 11 is wound into the electrode assembly 11a, the first bent portion 112a of the positive electrode 11 is provided on the first connector 116, and each second connector 117 is located in the bending area 15. Along the winding direction of the electrode assembly 11a, when the length of the second connector 117 is less than the length of the corresponding position of the bending area 15, the second connector 117 and the end of the connected first electrode segment 11311 and / or the end of the second electrode segment 11312 form a positive electrode bent portion 112. When the length of the second connector 117 is exactly equal to the length of the corresponding position of the bent portion, one second connector 117 forms one positive electrode bent portion 112.

[0250] In some examples, such as Figures 22 to 24 As shown, the first electrode portion 1131 includes a first electrode segment 11311 and a second electrode segment 11312. The positive electrode 11 includes a second connector 117. The first connector 116 connects the second electrode portion 1132 and the second electrode segment 11312, and the second connector 117 connects the second electrode segment 11312 and the first electrode segment 11311, thus obtaining a positive electrode 11 with a continuous strip structure.

[0251] In some examples, the first electrode portion 1131 includes a first electrode segment 11311 and two second electrode segments 11312, and the positive electrode 11 includes two second connectors 117. A first connector 116 connects the second electrode portion 1132 and an adjacent second electrode segment 11312, a second connector 117 connects the two second electrode segments 11312, and another second connector 117 connects the first electrode segment 11311 and an adjacent second electrode segment 11312.

[0252] The second connector 117 being an insulating component means that the second connector 117 is a connector made of insulating material and does not provide positive electrode active material to participate in the chemical reaction.

[0253] In this embodiment, second connectors 117 are also provided at the locations of multiple positive electrode bends 112 in the inner ring of the electrode assembly 11a. The second connectors 117 replace a portion of the electrode body 113 during bending deformation. Thus, by breaking the first electrode portion 1131 into first electrode segments 11311 and second electrode segments 11312, and then using the second connectors 117 to cover and connect the broken positions of the first electrode portion 1131, the second connectors 117 are set as insulating components. This reduces the amount of positive electrode active material at locations with greater curvature in the inner ring of the electrode assembly 11a, thereby meeting the design requirement of excessive negative electrode active material.

[0254] In this embodiment, it can be understood that the plurality of positive electrode straight portions 111 further include a plurality of third positive electrode straight portions 111c spaced apart along the winding direction, the second positive electrode straight portion 111b is disposed on the second electrode segment 11312 adjacent to the second electrode portion 1132, and the plurality of third positive electrode straight portions 111c are spaced apart on the first electrode segment 11311 along the winding direction.

[0255] In some embodiments, the second connector 117 is a flexible connector. Thus, by using the flexible second connector 117 instead of the electrode body 113 to bend and deform within the bending region 15, the probability of the positive electrode 11 breaking in the bending region 15 can be further reduced, thereby reducing the probability of the positive electrode 11 brittlely breaking and puncturing the separator 13, and further improving the electrical reliability of the electrode assembly 11a and the battery cell 10.

[0256] Understandably, the second connector 117 being a flexible connector means that the second connector 117 is a connector that is easy to bend, deformable and not easy to break. Its stiffness is less than that of the electrode body 113, and its hardness is also less than that of the electrode body 113, so that the second connector 117 is easier to bend and deform than the electrode body 113.

[0257] In a specific embodiment, the second connector 117 can be a polyethylene terephthalate (PET) component, a polyimide component, or a polypropylene component. PET, polyimide, or polypropylene are all high-molecular-weight ion-barrier materials. Connectors made from these materials are used to connect to the cut positions of the first electrode portion 1131. They do not provide positive electrode active material for electrochemical reactions, while also possessing higher flexibility, reducing the probability of breakage of the positive electrode 11 through bending and deformation.

[0258] For example, the second connector 117 can also be adhesive tape.

[0259] In some embodiments, such as Figure 24 As shown, along the winding direction, the two ends of the second connector 117 are respectively attached to the surfaces of two adjacent second pole segments 11312; or, one end of the second connector 117 is attached to the surface of the second pole segment 11312 and the other end is attached to the surface of the first pole segment 11311.

[0260] In this embodiment, the second connector 117 covers the end surface of the cut opening of each electrode segment. The second connector 117 can also cover and protect each cut position of the first electrode portion 1131 to cover and block the burrs at the cut opening formed by cutting, reduce the probability of burrs piercing the isolator 13 and causing short circuit, and further improve the electrical reliability of the electrode assembly 11a.

[0261] In some embodiments, such as Figure 24 As shown, the second connector 117 includes a third sub-part 1171 and a fourth sub-part 1172. Along the winding direction, the two ends of the third sub-part 1171 are respectively attached to the inner surfaces of two adjacent second pole segments 11312, and the two ends of the fourth sub-part 1172 are respectively attached to the outer surfaces of two adjacent second pole segments 11312; or, one end of the third sub-part 1171 is attached to the inner surface of the second pole segment 11312 and the other end is attached to the inner surface of the first pole segment 11311, and one end of the fourth sub-part 1172 is attached to the outer surface of the second pole segment 11312 and the other end is attached to the outer surface of the first pole segment 11311.

[0262] In this embodiment, the second connector 117 is connected to both sides of the electrode body 113 along the thickness direction at the same time. Thus, the third sub-part 1171 of the second connector 117 covers the burrs on the inner surface of the cut formed towards the center of the electrode assembly 11a, and the fourth sub-part 1172 covers the burrs on the outer surface of the cut formed away from the center of the electrode assembly 11a.

[0263] Of course, it is understood that in other embodiments, a second connector 117 may be provided on either side of the electrode body 113 along the thickness direction for connection.

[0264] In some embodiments, such as Figure 23 As shown, the protrusion thickness of the third sub-part 1171 and the fourth sub-part 1172 from the corresponding first electrode part 1131 or second electrode part 1132 is 0.003mm to 2mm.

[0265] That is, in a specific embodiment, the protrusion thickness D5 of the third sub-part 1171 from the first electrode portion 1131 is 0.003mm to 2mm, the protrusion thickness D6 of the fourth sub-part 1172 from the first electrode portion 1131 is 0.003mm to 2mm, the protrusion thickness of the third sub-part 1171 from the second electrode portion 1132 (first electrode segment 11311 or second electrode segment 11312) is 0.003mm to 2mm, and the protrusion thickness of the fourth sub-part 1172 from the second electrode portion 1132 (first electrode segment 11311 or second electrode segment 11312) is 0.003mm to 2mm. Thus, the protrusion thickness of the third sub-part 1171 and the protrusion thickness of the fourth sub-part 1172 are the protrusion heights of the third sub-part 1171 or the fourth sub-part 1172 from the surface of the electrode body 113. This protrusion height will affect the volume of the electrode assembly 11a. By setting the protrusion thickness of the third sub-part 1171 and the protrusion thickness of the fourth sub-part 1172 within the aforementioned thickness range, the second connector 117 can serve both as a connector and an ion barrier, while not occupying too much space, and the energy density of the electrode assembly 11a will not be significantly reduced due to the installation of the second connector 117.

[0266] In a specific embodiment, the protruding thickness of the self-electrode body 113 of the third sub-part 1171 can be 0.003mm, 0.01mm, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, or 2mm, etc., and the protruding thickness of the self-electrode body 113 of the fourth sub-part 1172 can be 0.003mm, 0.01mm, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, or 2mm, etc. The specific thickness values ​​of the third sub-part 1171 and the fourth sub-part 1172 are not uniquely limited here, and can be selected as needed during design.

[0267] In some embodiments, such as Figures 22 to 25As shown, taking the positive electrode 11 including a first connector 116 and two second connectors 117, and the first electrode portion 1131 including a first electrode segment 11311 and two second electrode segments 11312 as an example, the electrode assembly 11a in the above embodiment can be manufactured using the following manufacturing method for the electrode assembly 11a. Specifically, the method includes:

[0268] Step S100c: Provide the isolation component 13, the negative electrode material receiving assembly and the positive electrode material receiving assembly, wherein the negative electrode material receiving assembly includes a negative electrode sheet 12, and the positive electrode material receiving assembly includes an electrode sheet body 113, a first connector 116 and two second connectors 117, the first connector 116 is an insulating component, and the second connectors 117 are insulating components;

[0269] Step S200c: Cut the electrode body 113 to form a first electrode portion 1131 and a second electrode portion 1132;

[0270] Step S2001: Perform two cutting operations on the first electrode portion 1131 to form a first electrode segment 11311 and two second electrode segments 11312;

[0271] Step S300c: Cover the first connector 116 and the second connector 117 onto the corresponding cut-off portion of the electrode body 113. The first connector 116 connects the second electrode portion 1132 and the second electrode segment 11312. One of the second connectors 117 connects the two second electrode segments 11312 and the other connects the second electrode segment 11312 and the first electrode segment 11311, thereby connecting the cut-off first electrode portion 1131, the first electrode segment 11311 and the second electrode segment 11312 to form an integral positive electrode 11.

[0272] Step S400c: The separator 13, the negative electrode 12 and the positive electrode 11 are fed into the winding mechanism to be wound to form a wound body;

[0273] Step S500c: The wound body is shaped to obtain an electrode assembly 11a with a flat structure; wherein, the electrode assembly 11a has a flat region 14 and bending regions 15 located at opposite ends of the flat region 14, the positive electrode 11 includes a plurality of positive electrode flat portions 111 disposed in the flat region 14, the negative electrode 12 includes a plurality of negative electrode flat portions 121 disposed in the flat region 14, and along the thickness direction of the electrode assembly 11a, the plurality of positive electrode flat portions 111 and the plurality of negative electrode flat portions 121 are staggered and stacked, the positive electrode 11 also includes a plurality of positive electrode bending portions 112 disposed in the bending regions 15, and the positive electrode flat portions 111 are connected to each positive electrode bending portion. At the end of 112, along the winding direction, the second electrode portion 1132, the second electrode segment 11312, and the first electrode segment 11311 are arranged sequentially at intervals. The first connector 116 connects the second electrode portion 1132 and an adjacent second electrode segment 11312. Two adjacent second electrode segments 11312 are connected by a second connector 117. At the same time, an adjacent second electrode segment 11312 is connected to the first electrode segment 11311 by a second connector 117. The first bending portion 112a of the positive electrode 11 is provided on the first connector 116, and each second connector 117 is located in the bending area 15.

[0274] In this manufacturing method, unlike the aforementioned manufacturing method, in step S100c, the positive electrode material assembly includes an electrode body 113, a first connector 116, and two second connectors 117. The second connectors 117 can be one of polyethylene terephthalate, polyimide, or polypropylene. The second connectors 117 have a sheet-like structure. It should be understood that the length of the second connectors 117 is shorter than the length of the electrode body 113. Step S2001 is performed after step S200c and before step S300c, in which the first electrode portion 1131 is cut twice to form one first electrode segment 11311 and two second electrode segments 11312. In step S300c, the second electrode portion 1132 and the adjacent second electrode segment 11312 are connected using the first connector 116, the two second electrode segments 11312 are connected using the second connector 117, and the second electrode segment 11312 and the adjacent first electrode segment 11311 are connected using the second connector 117, thereby obtaining the positive electrode 11. Apart from this, the other steps are basically the same as those in the above embodiment, and will not be repeated here.

[0275] Thus, in the electrode assembly 11a manufactured using the above-described manufacturing method, a second connector 117 is provided to replace part of the electrode body 113 within the bending area 15. The second connector 117 replaces part of the electrode body 113 for bending deformation. After the first electrode portion 1131 is broken into a first electrode segment 11311 and a second electrode segment 11312, the second connector 117 is used to cover the broken position of the first electrode portion 1131 and connect them. The second connector 117 is set as an insulating member, thereby reducing the amount of positive electrode active material at various positions with large curvature in the inner circle of the electrode assembly 11a to meet the design requirement of excessive negative electrode active material. In addition, the second connector 117 can also be a flexible connector, that is, the flexible second connector 117 can replace the electrode body 113 to bend and deform in the bending area 15, which can further reduce the probability of the positive electrode 11 breaking in the bending area 15, thereby reducing the probability of the positive electrode 11 breaking brittlely and puncturing the separator 13, and further improving the electrical reliability of the electrode assembly 11a and the battery cell 10.

[0276] In other embodiments of this application, such as Figure 26 As shown, unlike the embodiments described above, the positive electrode 11 also includes a second insulating member 115. Along the winding direction of the electrode assembly 11a, the second insulating member 115 and the insulating surface 1121 are spaced apart. The plurality of positive electrode straight portions 111 also include a plurality of third positive electrode straight portions 111c spaced apart along the winding direction of the positive electrode 11. The plurality of positive electrode bent portions 112 also include a second bent portion 112b and at least one third bent portion 112c. A third positive electrode straight portion 111c is connected to the second positive electrode straight portion 111b through the second bent portion 112b. Two third positive electrode straight portions 111c arranged adjacent to each other along the winding direction are connected through a third bent portion 112c. The second insulating member 115 is attached to the surface of at least the second bent portion 112b facing the center of the electrode assembly 11a.

[0277] In this embodiment, the positive electrode 11 includes an electrode body and a first connector 116. The electrode body 113 includes a first electrode portion 1131 and a second electrode portion 1132. Along the winding direction of the electrode assembly 11a, the second electrode portion 1132 and the first electrode portion 1131 are spaced apart. The first electrode portion 1131 is continuously wound. A first positive electrode straight portion 111a is disposed on the second electrode portion 1132, and a second positive electrode straight portion 111b is disposed on the first electrode portion 1131. The first connector 116 connects the second electrode portion 1132 and the first electrode portion 1131 along the winding direction. The plurality of positive electrode straight portions 111 of the positive electrode 11 also include a plurality of third positive electrode straight portions 111c, and the plurality of positive electrode bent portions 112 also include a second bent portion 112b and at least one third bent portion 112c. Unlike the aforementioned embodiments, the third positive electrode straight portion 111c, the second bent portion 112b, and the third bent portion 112c are all located on the first electrode portion 1131; the second insulating member 115 and the insulating surface 1121 are spaced apart, meaning that along the winding direction of the electrode assembly 11a, the second insulating member 115 is spaced apart downstream of the first connector 116, and the starting end of the second insulating member 115 along the winding direction and the ending end of the first connector 116 along the winding direction are spaced apart.

[0278] Thus, similar to the above embodiments, in this embodiment, the second bending portion 112b is the bending portion with the largest curvature among the plurality of positive electrode bending portions 112 except for the first bending portion 112a. At least the inner surface of the second bending portion 112b is attached with a second insulating member 115. The second insulating member 115 can block at least a portion of the positive electrode active material disposed at the bending portion, thereby making the amount of negative electrode active material in the electrode assembly 11a at this position greater than that of the positive electrode active material, so as to meet the design requirement of excess negative electrode active material.

[0279] In a specific embodiment, such as Figure 26 As shown, the electrode assembly 11a may include a second insulating member 115, which is attached to the inner surface of the second bent portion 112b.

[0280] Alternatively, in other embodiments, the electrode assembly 11a includes a plurality of second insulating members 115. Along the winding direction of the electrode assembly 11a, the plurality of second insulating members 115 are sequentially and spaced apart. The surface of the second bent portion 112b facing the center of the electrode assembly 11a is covered with a second insulating member 115, and at least the surface of the first third bent portion 112c adjacent to the second bent portion 112b facing the center of the electrode assembly 11a is covered with a second insulating member 115. Specifically, the electrode assembly 11a includes a plurality of second insulating members 115. The starting end of the first second insulating member 115 located at the starting end along the winding direction is spaced apart from the ending end of the first connector 116. Along the winding direction of the electrode assembly 11a, subsequent second second insulating members 115 and a plurality of subsequent second insulating members 115 are sequentially and spaced apart.

[0281] As an example, electrode assembly 11a includes two second insulating members 115, which are arranged continuously at intervals. One second insulating member 115 is attached to the inner surface of the second bend 112b, and the other second insulating member 115 is attached to the inner surface of the first third bend 112c adjacent to the second bend 112b; or, electrode assembly 11a includes three or more second insulating members 115, one of which is attached to the inner surface of the second bend 112b. On the surface, a second insulating member 115 is attached to the inner surface of the first third bend 112c adjacent to the second bend 112b, and the remaining one or more second insulating members 115 are attached to the inner surface of the subsequent one or more third bends 112c in a corresponding manner. For example, multiple second insulating members 115 are attached to the inner surfaces of the second third bend 112c, the third third bend 112c, the fourth third bend 112c and each subsequent third bend 112c.

[0282] Thus, a second insulating member 115 is attached to the inner surface of the second bend 112b and one or more third bends 112c located in the inner ring of the positive electrode sheet 11. That is, the second insulating member 115 is attached to the inner surface of the multiple positive electrode bends 112 located in the inner ring of the positive electrode sheet 11 and the electrode assembly 11a. At the position of large curvature in the inner ring of the electrode assembly 11a, by setting the second insulating member 115 to cover part of the positive electrode active material on the inner surface of the positive electrode bend 112, the electrode assembly 11a can meet the design requirements of excessive negative electrode active material at the positions with large curvature.

[0283] Another embodiment of this application provides a battery device 200, including the battery cell 10 provided in the above embodiments.

[0284] The electrical device of this application, since it uses the aforementioned battery cell 10, includes at least all the beneficial effects of the aforementioned battery cell 10, which will not be repeated here.

[0285] Another embodiment of this application provides an electrical device, including the battery cell 10 provided in the above embodiments, and / or the battery device 200 provided in the above embodiments.

[0286] The electrical device of this application, since it employs at least one of the aforementioned battery cell 10 and battery device 200, therefore includes at least all the beneficial effects of the aforementioned battery cell 10 or battery device 200, which will not be elaborated here.

[0287] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0288] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The application relates to a battery, which comprises: a shell provided with a cavity; an electrode assembly accommodated in the cavity; the electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator, the separator is arranged between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet, the separator and the negative electrode sheet are arranged in a laminated and coiled mode, the positive electrode sheet comprises a plurality of positive electrode flat parts and a plurality of positive electrode bending parts connected to the positive electrode flat parts, the negative electrode sheet comprises a plurality of negative electrode flat parts and a plurality of negative electrode bending parts connected to the negative electrode flat parts, and the plurality of positive electrode flat parts and the plurality of negative electrode flat parts are arranged in a staggered mode along the thickness direction of the electrode assembly; wherein the plurality of positive electrode flat parts comprises a first positive electrode flat part and a second positive electrode flat part, the plurality of positive electrode bending parts comprises a first bending part, the first positive electrode flat part is located at the coiled starting end of the positive electrode sheet in the coiling direction, and the second positive electrode flat part is connected to the first positive electrode flat part through the first bending part; the plurality of negative electrode flat parts comprises a first negative electrode flat part, the first negative electrode flat part is located at the coiled starting end of the negative electrode sheet in the coiling direction, the first negative electrode flat part is located between the first positive electrode flat part and the second positive electrode flat part along the thickness direction of the electrode assembly, and the first bending part is arranged to face the coiled starting end of the negative electrode sheet; the positive electrode sheet comprises a sheet main body and a first connecting piece, the sheet main body comprises a first sheet part and a second sheet part, the second sheet part is arranged at intervals from the first sheet part along the coiling direction of the electrode assembly, the first sheet part is continuously coiled, the first positive electrode flat part is arranged at the second sheet part, the second positive electrode flat part is arranged at the first sheet part, the first connecting piece connects the second sheet part and the first sheet part along the coiling direction, the first bending part is arranged at the first connecting piece, the first connecting piece is an insulating piece, the surface of the first connecting piece towards the center of the electrode assembly is an insulating surface, the two ends of the insulating surface extend to the first positive electrode flat part and the second positive electrode flat part, and the projection of the insulating surface at least partially overlaps the projection of the first negative electrode flat part along the thickness direction of the electrode assembly.

2. The battery cell of claim 1, wherein, a layer of the separator is arranged between the first positive electrode flat part and the first negative electrode flat part.

3. The battery cell of claim 2, wherein, the coiled starting end of the separator exceeds the first positive electrode flat part in the direction opposite to the coiling direction of the electrode assembly.

4. The battery cell of claim 3, wherein, the plurality of negative electrode bending parts comprises a first negative electrode bending part, the plurality of negative electrode flat parts further comprises a second negative electrode flat part, the second negative electrode flat part is connected to the first negative electrode flat part through the first negative electrode bending part, and the coiled starting end of the separator is arranged on the surface of the first negative electrode bending part towards the center of the electrode assembly; alternatively, the coiled starting end of the separator is arranged on the surface of the first negative electrode flat part facing the center of the electrode assembly, and the projection of the coiled starting end of the separator does not overlap the projection of the first positive electrode flat part along the thickness direction of the electrode assembly.

5. The battery cell of claim 2, wherein, The winding start end of the separator is beyond the winding start end of the first negative flat portion in a direction opposite to the winding direction of the electrode assembly.

6. The battery cell of claim 5, wherein, The winding start end of the separator is attached to the insulating surface, and a projection of the winding start end of the separator does not overlap with a projection of the first negative flat portion in a thickness direction of the electrode assembly.

7. The battery cell of claim 1, wherein, The length of the overlapping part of the projection of the insulating surface and the projection of the first negative flat portion is 0.05mm-300mm.

8. The battery cell of claim 1, wherein, The first connecting member is a flexible connecting member.

9. The battery cell of claim 1, wherein, The first connecting member is a polyethylene terephthalate member, a polyimide member, or a polypropylene member.

10. The battery cell of claim 1, wherein, One end of the first connecting member is attached to a surface of the first tab portion, and the other end of the first connecting member is attached to a surface of the second tab portion.

11. The battery cell of claim 1, wherein, The first connecting member includes a first sub-portion and a second sub-portion, one end of the first sub-portion is attached to a surface of the first tab portion facing the center of the electrode assembly, the other end of the first sub-portion is attached to a surface of the second tab portion facing the center of the electrode assembly, one end of the second sub-portion is attached to a surface of the first tab portion away from the center of the electrode assembly, and the other end of the second sub-portion is attached to a surface of the second tab portion away from the center of the electrode assembly.

12. The battery cell of claim 11, wherein, The protruding thickness of the first sub-portion and the second sub-portion from the corresponding first tab portion or second tab portion is 0.003mm-2mm.

13. The battery cell of any one of claims 1-12, wherein, The positive tab further includes at least one second connecting member, the first tab portion includes one first tab segment and at least one second tab segment, the second tab portion is arranged spaced apart from the first tab segment in a winding direction of the electrode assembly, the second tab segment is arranged spaced apart between the second tab portion and the first tab segment, and the first tab segment is continuously wound; The first connecting member connects the second tab portion and an adjacent second tab segment, the second connecting member connects two adjacent second tab segments, and / or the second connecting member connects an adjacent second tab segment and the first tab segment; The second connecting member is an insulating member.

14. The battery cell of claim 13, wherein, The first tab portion includes a plurality of second tab segments, the positive tab includes a plurality of second connecting members, the second connecting members connect two adjacent second tab segments, and connect an adjacent second tab segment and the first tab segment.

15. The battery cell of claim 13, wherein, The second connecting member is a flexible connecting member.

16. The battery cell of claim 13, wherein, The second connecting member is a polyethylene terephthalate member, a polyimide member, or a polypropylene member.

17. The battery cell of any one of claims 1-12, wherein, The electrode assembly further includes a second insulating member, the second insulating member is arranged spaced apart from the insulating surface in a winding direction of the electrode assembly, the plurality of positive flat portions further include a plurality of third positive flat portions arranged spaced apart in the winding direction of the positive tab, the plurality of positive bending portions further include one second bending portion and at least one third bending portion, one third positive flat portion is connected to the second positive flat portion through the second bending portion, and two third positive flat portions arranged adjacent in the winding direction are connected through one third bending portion; At least a surface of the second bending portion facing the center of the electrode assembly is attached with the second insulating member.

18. The battery cell of claim 17, wherein, The electrode assembly includes a plurality of the second insulating members, and the plurality of the second insulating members are sequentially and spaced apart in a winding direction of the electrode assembly. At least a surface of a first third bending portion adjacent to the second bending portion faces the center of the electrode assembly and is attached with the second insulating member.

19. The battery cell of claim 17, wherein, The second insulating member is a polyethylene terephthalate film, a polyimide film, or a polypropylene film.

20. A battery device, characterized by A battery cell including any one of claims 1 to 19.

21. An electrical device, comprising: A battery cell including any one of claims 1 to 19, and / or a battery device including claim 20.

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