WO2024031255A1

WO2024031255A1 - Electrode assembly, battery cell, battery, and electric device

Info

Publication number: WO2024031255A1
Application number: PCT/CN2022/110920
Authority: WO
Inventors: 陈江; 周建华; 宋晋阳; 吴凯
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-08-08
Filing date: 2022-08-08
Publication date: 2024-02-15
Also published as: CN117543094A

Abstract

The present application relates to the field of batteries. Provided are an electrode assembly, a battery cell, a battery and an electric device. The battery cell comprises a first electrode plate, a second electrode plate, a separator and a protective member, wherein the first electrode plate and the second electrode plate have opposite polarities, and the first electrode plate, the separator and the second electrode plate are wound in a winding direction to form the electrode assembly; the first electrode plate has a first terminated end; and the protective member is arranged on the first electrode plate and/or the second electrode plate, and is configured to prevent the first terminated end from coming into contact with the portions of the first electrode plate and the second electrode plate that are adjacent to the first terminated end. The electrode assembly is provided with the protective member which can prevent the first terminated end from coming into contact with the portions of the first electrode plate and the second electrode plate that are adjacent to the first terminated end so as to reduce the shear force of the first terminated end on the portions, which reduces the risk of the electrode plates cracking from the portions and thus also reduce the risk of burrs and debris, which are generated at a cracking position, piercing the separator, such that the electrode assembly does not easily short-circuited, thereby improving safety of the electrode assembly.

Description

Electrode components, battery cells, batteries and electrical equipment

Technical field

The present application relates to the field of batteries, specifically, to an electrode assembly, a battery cell, a battery and electrical equipment.

Background technique

Batteries are widely used in the field of new energy, such as electric vehicles and new energy vehicles. New energy vehicles and electric vehicles have become a new development trend in the automobile industry. The development of battery technology must consider multiple design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery safety also needs to be considered. However, current battery cells using wound electrode assemblies are less safe.

Contents of the invention

The purpose of the embodiments of the present application is to provide an electrode assembly, a battery cell, a battery and an electrical device, which is intended to improve the problem of poor safety of battery cells using wound electrode assemblies in related technologies.

In a first aspect, embodiments of the present application provide an electrode assembly. The electrode assembly includes a first pole piece, a second pole piece, an isolation film and a protective member. The first pole piece and the second pole piece are The polarity is opposite, the first pole piece, the isolation film and the second pole piece are rolled along the winding direction to form the electrode assembly, the first pole piece has a first ending end; the protective member Disposed on the first pole piece and/or the second pole piece, and configured to prevent the first ending end from connecting with the first pole piece and the second pole piece and the first ending end. adjacent parts are in contact.

In the above technical solution, the electrode assembly is provided with a protective piece. The protective piece can prevent the first ending end from contacting the parts of the first pole piece and the second pole piece adjacent to the first ending end, thereby reducing the size of the first ending end. The shear force on this part makes it less likely to strain, thereby reducing the risk of the pole piece cracking from this part, and also reducing the risk of burrs and debris generated at the cracking location piercing the isolation membrane, making the first pole The electrode piece and the second pole piece are not easy to contact and short-circuit, which improves the safety of the electrode assembly.

As an optional technical solution of the embodiment of the present application, the protective member includes a first protective member, the second pole piece has a second ending end, and the first pole piece is partially located outside the second ending end. , and the first ending end exceeds the second ending end along the winding direction, and the first protection member is provided on the first pole piece to prevent the first ending end from being adjacent to it. of the first pole piece contact.

In the above technical solution, the first pole piece may be a negative pole piece, the second pole piece may be a positive pole piece, and the first ending end exceeds the second ending end along the winding direction, so that the first pole piece covers the second pole piece , to avoid lithium precipitation. Since the first pole piece is located outside the second ending end, the first pole piece adjacent to the first ending end among the first pole piece and the second pole piece is the first pole piece. Therefore, the first protection member is disposed on the first pole piece. , can more conveniently separate the first ending end from the adjacent first pole piece, reduce the shearing force of the first ending end on the adjacent first pole piece, and the first pole piece is less likely to crack, so as to Improve the safety of electrode components.

As an optional technical solution in the embodiment of the present application, along the radial direction of the electrode assembly, the first pole piece includes a plurality of arc segments, and the projection of the first ending end is located at the projection of the arc segment. Inside, the outermost arc segment among the plurality of arc segments is the first arc segment, and the first protective member is provided on the outer surface of the first arc segment.

In the above technical solution, the first arc segment is the arc segment closest to the first ending end among the multiple arc segments, and is also the arc segment most susceptible to the shear force of the first ending end. Therefore, the first arc segment is The protective piece is disposed on the outer surface of the first arc segment to protect the first arc segment, reduce the risk of cracking of the first arc segment, and improve the safety of the electrode assembly.

As an optional technical solution of the embodiment of the present application, the first protective member is provided on the inner surface of the first arc segment along the radial direction of the electrode assembly.

In the above technical solution, by also disposing the first protective member on the inner surface of the first arc segment, on the one hand, the tensile strength of the first arc segment can be increased, making the first arc segment less likely to be pulled when expanding. break. On the other hand, if the first arc segment cracks, the newly generated step surface at the crack position will be blocked by the first protective member provided inside the first arc segment, thereby preventing the newly generated step surface from being located on the first arc segment. The inner arc segment exerts shear force to reduce the risk of cracking in the arc segment located inside the first arc segment.

As an optional technical solution in the embodiment of the present application, the arc segment located inside the first arc segment among the plurality of arc segments is a second arc segment, and at least one of the second arc segments The first protective piece is provided.

In the above technical solution, by arranging the first protective member on at least one second arc segment, on the one hand, the tensile strength of the second arc segment can be increased, making the second arc segment less likely to be broken when expanding ( Due to the influence of fluctuations in the production process, the mechanical properties of the second arc segment at different positions are different, and the second arc segment may be broken before the first arc segment). On the other hand, if cracking occurs in the first arc segment, a new step surface will be generated at the cracking position, and the new step surface acting on the second arc segment will cause the second arc segment to crack. By setting the The first protective piece can protect the second arc segment, reduce the stress of the newly generated step on the second arc segment, and reduce the risk of cracking in the second arc segment.

As an optional technical solution of the embodiment of the present application, the protective member further includes a second protective member, and along the radial direction of the electrode assembly, the second pole piece includes a plurality of third arc segments, and the The projection of the first ending end is located within the projection of the third arc segment, and at least one of the third arc segments is provided with the second protection member.

In the above technical solution, by arranging the second protective member on at least one third arc segment, on the one hand, the tensile strength of the third arc segment can be increased, making the third arc segment less likely to be broken during expansion ( Due to the influence of fluctuations in the production process, the mechanical properties of the third arc segment located at different locations are different, and the third arc segment may be broken). On the other hand, if cracking occurs in the third arc segment, a new step surface will be generated at the cracking position. The new step surface acting on the second arc segment will cause the second arc segment to crack. By setting the The second protective piece can protect the third arc segment and reduce the risk of cracking in the third arc segment. In addition, when the second arc segment or the first arc segment cracks, the second protective member can also reduce the shear force of the third arc segment from the newly generated step surface, so as to reduce the occurrence of cracks in the third arc segment. Risk of cracking.

As an optional technical solution of the embodiment of the present application, the second protection member is provided on both sides of at least one third arc segment along the radial direction of the electrode assembly.

In the above technical solution, by arranging second protection members on both sides of the third arc segment, the tensile strength of the third arc segment can be increased, making the third arc segment less likely to be broken during expansion. If cracking occurs in the third arc segment, the newly generated step surface at the cracked position will be blocked by the second protective member provided inside the third arc segment, thereby preventing the newly generated step surface from facing the arc located inside the third arc segment. Apply shear force to the segment to reduce the risk of cracking in the arc segment located inside the third arc segment.

As an optional technical solution in the embodiment of the present application, along the radial direction of the electrode assembly, the first pole piece includes a plurality of arc segments, and the projection of the first ending end is located on the arc segment, so The outermost arc segment among the plurality of arc segments is the first arc segment, and the first protective member covers the first arc segment.

In the above technical solution, by arranging the first protective member to cover the first arc segment, while increasing the tensile strength of the first arc segment, even if the first arc segment cracks, the new step generated will be blocked by the first arc segment. The shielding by the protective member will not have much impact on other arc segments located inside the first arc segment. The coating method can better protect the first arc segment and improve the safety of the electrode assembly.

As an optional technical solution of the embodiment of the present application, the protective member includes a second protective member, and along the radial direction of the electrode assembly, the second pole piece includes a plurality of third arc segments, and the third arc segment The projection of a tail end is located within the projection of the third arc segment, and at least one of the third arc segments is covered by the second protective member.

In the above technical solution, by arranging the second protective member to cover the third arc segment, while increasing the tensile strength of the third arc segment, even if the third arc segment cracks, the new steps generated will be blocked by the second arc segment. The protection piece shields and will not have much impact on other arc segments located inside the third arc segment. The coating method can better protect the third arc segment and improve the safety of the electrode assembly.

As an optional technical solution in the embodiment of the present application, the protection member further includes a third protection member, and the third protection member is used to prevent the second tail end from contacting the first pole piece.

In the above technical solution, since the first pole piece is located outside the second ending end, the first pole piece and the second pole piece are adjacent to the second ending end. Therefore, the third protection member Disposed on the first pole piece, it can more conveniently separate the second ending end from the adjacent first pole piece, and reduce the shearing force of the second ending end on the adjacent first pole piece. The sheet is not prone to cracking to improve the safety of the electrode assembly.

As an optional technical solution of the embodiment of the present application, the part of the first pole piece located outside the second ending end and/or the part of the first pole piece located inside the second ending end is provided with The third protective piece.

In the above technical solution, both the part of the first pole piece located outside the second ending end and the part of the first pole piece located inside the second ending end may be affected by the shearing force of the second ending end. Therefore, at the first pole The portion of the pole piece located outside the second ending end and the portion of the first pole piece located inside the second ending end are provided with a third protective piece to protect the first pole piece, reduce the risk of cracking of the first pole piece, and provide the safety of the electrode assembly. safety.

As an optional technical solution in the embodiment of the present application, along the radial direction of the electrode assembly, the first pole piece includes a fourth arc segment, and the projection of the second ending end is located in the fourth arc segment. In the projection, the fourth arc segment is adjacent to the second ending end, and the third protective member is provided on the surface of the fourth arc segment facing the second ending end.

In the above technical solution, the fourth arc segment is the position on the first pole piece that is most susceptible to cracking due to the shear force of the second ending end. By setting a third protection on the surface of the fourth arc segment facing the second ending end piece to protect the fourth arc segment and reduce the risk of cracking of the first pole piece due to the shear force of the second ending end.

As an optional technical solution in the embodiment of the present application, along the radial direction of the electrode assembly, the first pole piece includes a fifth arc segment, and the projection of the second ending end is located in the fifth arc segment. In the projection, the fifth arc segment is located inside the fourth arc segment, and at least one of the fifth arc segments is provided with the third protection member.

In the above technical solution, by arranging a third protective member on at least one fifth arc segment, on the one hand, the tensile strength of the fifth arc segment can be increased, making the fifth arc segment less likely to be broken when expanding ( Due to the influence of fluctuations in the production process, the mechanical properties of the fifth arc segment located at different positions are different, and the fifth arc segment may be broken before the fourth arc segment). On the other hand, if cracking occurs in the fourth arc segment, a new step surface will be generated at the cracking position. The new step surface acting on the fifth arc segment will cause the fifth arc segment to crack. By setting the The third protective piece can protect the fifth arc segment, reduce the stress of the newly generated step on the fifth arc segment, and reduce the risk of cracking in the fifth arc segment.

As an optional technical solution in the embodiment of the present application, the protective member further includes a fourth protective member, and along the radial direction of the electrode assembly, the second pole piece includes a plurality of sixth arc segments, and the The projection of the second ending end is located within the projection of the sixth arc segment, and at least one of the sixth arc segments is provided with the fourth protective member.

In the above technical solution, by arranging the fourth protective member on at least one sixth arc segment, on the one hand, the tensile strength of the sixth arc segment can be increased, making the sixth arc segment less likely to be broken during expansion ( Due to the influence of fluctuations in the production process, the mechanical properties of the sixth arc segment located at different locations are different, and the sixth arc segment may be broken). On the other hand, if the sixth arc segment cracks, a new step surface will be generated at the cracking position, and the new step surface acting on the fifth arc segment will cause the fifth arc segment to crack. By setting the sixth arc segment The fourth protective piece can protect the sixth arc segment and reduce the risk of cracking in the sixth arc segment. In addition, when the fourth arc segment or the fifth arc segment cracks, the fourth protective member can also reduce the shear force of the sixth arc segment from the newly generated step surface, so as to reduce the occurrence of cracks in the sixth arc segment. Risk of cracking.

As an optional technical solution in the embodiment of the present application, along the radial direction of the electrode assembly, the first pole piece includes a fourth arc segment, and the projection of the second ending end is located in the fourth arc segment. In the projection, the fourth arc segment is adjacent to the second ending end, and the third protective member covers the fourth arc segment.

In the above technical solution, by arranging the third protective member to cover the fourth arc segment, while increasing the tensile strength of the fourth arc segment, even if the fourth arc segment cracks, the new steps generated will be blocked by the third arc segment. The shielding by the protective member will not have much impact on other arc segments located inside the fourth arc segment. The coating method can better protect the fourth arc segment and improve the safety of the electrode assembly.

As an optional technical solution in the embodiment of the present application, the protective member further includes a fourth protective member, and along the radial direction of the electrode assembly, the second pole piece includes a plurality of sixth arc segments, and the The projection of the second ending end is located within the projection of the sixth arc segment, and at least one of the sixth arc segments is covered by the fourth protective member.

In the above technical solution, by arranging the fourth protective member to cover the sixth arc segment, while increasing the tensile strength of the sixth arc segment, even if the sixth arc segment cracks, the new steps generated will be blocked by the fourth arc segment. The shielding by the protective member will not have much impact on other arc segments located inside the sixth arc segment. The coating method can better protect the sixth arc segment and improve the safety of the electrode assembly.

As an optional technical solution for the embodiment of the present application, along the first direction, the size of the protective member is D1, the size of the first pole piece is D2, and D1/D2≥1/2 is satisfied; the third One direction is parallel to the winding axis.

In the above technical solution, the size of the protective member in the first direction is greater than or equal to half of the size of the first pole piece in the first direction, so as to achieve a better protection effect on the first pole piece. If D1/D2<1/2, the protection effect of the protective member on the first pole piece is not good. Compared with the solution where D1/D2≥1/2, the risk of cracking of the first pole piece is greater.

As an optional technical solution of the embodiment of the present application, along the first direction, the protective member is located in the middle of the corresponding first pole piece or second pole piece.

In the above technical solution, the middle part of the first pole piece and the second pole piece is a relatively easy position to crack. Therefore, if the length of the protective member in the first direction is smaller than the length of the first pole piece or the second pole piece in the first direction, length, priority is given to protecting the middle part of the first pole piece or the second pole piece.

As an optional technical solution for the embodiment of the present application, along the winding direction, the distance beyond the first ending end beyond the second ending end is L1, which satisfies: L1≤20mm; the first protective member and the third protective member are the same component; or the first protective member and the third protective member are partially overlapped.

In the above technical solution, if the distance between the first ending end and the second ending end is less than or equal to 20 mm along the winding direction, then the distance between the first ending end and the second ending end is relatively close, and the first protective member and the second ending end can be separated. The three protective pieces are provided as the same component, and the first protective piece and the second protective piece can also be partially overlapped to protect the first pole piece.

As an optional technical solution in the embodiment of the present application, the first protective member and the third protective member are partially overlapped, and along the winding direction, the length of the overlapping portion is L2, which satisfies L2 ≥ 10 mm.

In the above technical solution, the first protective member and the third protective member are partially overlapped, and the overlapping part will generate a new step. When the length of the overlapping part L2 ≥ 10 mm, the impact of the new step on the first pole piece can be effectively transferred. Shearing force to prevent the first pole piece from cracking due to excessive local shearing force. If the length L2 of the overlapping part is less than 10mm, the new step created by the overlap of the first protective piece and the second protective piece will produce a large shear force on the first pole piece, causing local shear stress concentration on the first pole piece. , compared with L2≥10mm, the first pole piece has a greater risk of cracking.

As an optional technical solution in the embodiment of the present application, along the radial direction of the electrode assembly, the thickness of the protective member is T1, and the thickness of the first pole piece is T2, satisfying: T1<T2.

In the above technical solution, the thickness of the protective member is smaller than the thickness of the first pole piece. In this way, when the protective member is disposed on the first pole piece, the steps generated at the edge of the protective member protruding from the first pole piece have a negative impact on the first pole piece. The shearing force of the piece is small, and the first pole piece is not easy to crack. If the thickness of the protective member is greater than or equal to the thickness of the first pole piece, when the protective member is disposed on the first pole piece, the steps protruding from the first pole piece generated at the edge of the protective member will shear the first pole piece. Large shear force may cause the first pole piece to crack. In addition, when the thickness of the protective member is less than the thickness of the first pole piece, compared to when the thickness of the protective member is greater than or equal to the thickness of the first pole piece, the thickness of the protective member is thinner and occupies less space for the electrode assembly, which is beneficial to Increase energy density.

As an optional technical solution in the embodiment of the present application, the protective member includes a first protective member and a second protective member, and the first protective member covers the first ending end; and/or the third protective member The diode piece has a second ending end, and the second protection member covers the second ending end.

In the above technical solution, the first protective member covers the first ending end, which can effectively reduce the shearing force of the first ending end on the first pole piece and reduce the risk of cracking of the first pole piece. In addition, the first protective member covers the first ending end, which can block the burrs and debris on the first ending end and prevent the burrs and debris from penetrating the isolation film and causing a short circuit, which is beneficial to improving the safety of the electrode assembly. By covering the second ending end with the second protective piece, the shearing force exerted by the second ending end on the first pole piece can be effectively reduced and the risk of cracking of the first pole piece can be reduced. In addition, the second protective member covers the second ending end, which can block the burrs and debris at the second ending end, and prevent the burrs and debris from penetrating the isolation film and causing a short circuit, which is beneficial to improving the safety of the electrode assembly.

As an optional technical solution in the embodiment of the present application, the protective member is an adhesive tape, and the adhesive tape is bonded to the corresponding first pole piece or the second pole piece.

In the above technical solution, the adhesive tape is bonded to the first pole piece or the second pole piece, which has a better protective effect on the first pole piece or the second pole piece, is simple and convenient, and has low cost. In addition, the thickness of the tape is smaller, which is beneficial to increasing energy density.

In a second aspect, embodiments of the present application also provide a battery cell, which includes the above-mentioned electrode assembly, a casing and an end cover; the casing has an accommodating space with one end open, and the accommodating space is To accommodate the electrode assembly; the end cap is connected to the housing and closes the opening.

In a third aspect, embodiments of the present application further provide a battery, which includes a box and the above-mentioned battery cell, and the battery cell is accommodated in the box.

In a fourth aspect, embodiments of the present application further provide an electrical device, wherein the electrical device includes the above-mentioned battery, and the battery is used to provide electric energy.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and therefore do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application;

Figure 2 is an exploded view of a battery provided by some embodiments of the present application;

Figure 3 is a schematic structural diagram of a battery cell provided by some embodiments of the present application;

Figure 4 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (along the winding direction, the second ending end exceeds the first ending end, and a protective member is provided inside the first ending end);

Figure 5 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (along the winding direction, the second ending end exceeds the first ending end, and a protective member is provided outside the first ending end);

Figure 6 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (along the winding direction, the second ending end exceeds the first ending end, and protective elements are provided both inside and outside the first ending end);

Figure 7 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (along the winding direction, the first ending end exceeds the second ending end, and a protective member is provided inside the first ending end);

Figure 8 is a schematic structural diagram of an electrode assembly (first protection members are provided on both sides of the first arc segment) provided by some embodiments of the present application;

Figure 9 is a schematic structural diagram of an electrode assembly (with a first protective member provided on one side of the second arc segment) provided by some embodiments of the present application;

Figure 10 is a schematic structural diagram of an electrode assembly (with first protection members provided on both sides of the second arc segment) provided by some embodiments of the present application;

Figure 11 is a schematic structural diagram of an electrode assembly (a second protective member is provided on one side of the third arc segment) provided by some embodiments of the present application;

Figure 12 is a schematic structural diagram of an electrode assembly (with second protection members provided on both sides of the third arc segment) provided by some embodiments of the present application;

Figure 13 is a schematic structural diagram of an electrode assembly (the first protective member covers the first arc segment) provided by some embodiments of the present application;

Figure 14 is a schematic structural diagram of the first protective member covering the first arc segment provided by some embodiments of the present application;

Figure 15 is a schematic structural diagram of an electrode assembly (the first protective member covers the second arc segment) provided by some embodiments of the present application;

Figure 16 is a schematic structural diagram of an electrode assembly (the second protective member covers the third arc segment) provided by some embodiments of the present application;

Figure 17 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (the portion of the first pole piece located outside the second ending end is provided with a third protective member);

Figure 18 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (the portion of the first pole piece located inside the second ending end is provided with a third protective member);

Figure 19 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (the portions of the first pole piece located inside and outside the second ending end are both provided with third protection members);

Figure 20 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (third protection members are provided on both sides of the fourth arc segment);

Figure 21 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (a third protective member is provided on one side of the fifth arc segment);

Figure 22 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (third protection members are provided on both sides of the fifth arc segment);

Figure 23 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (a third protective member is provided on one side of the sixth arc segment);

Figure 24 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (third protection members are provided on both sides of the sixth arc segment);

Figure 25 is a schematic structural diagram of an electrode assembly (the third protective member covers the fourth arc segment) provided by some embodiments of the present application;

Figure 26 is a schematic structural diagram of an electrode assembly (the third protective member covers the fifth arc segment) provided by some embodiments of the present application;

Figure 27 is a schematic structural diagram of an electrode assembly (the fourth protective member covers the sixth arc segment) provided by some embodiments of the present application;

Figure 28 is a schematic structural diagram of the first protection member provided on one side of the first pole piece according to some embodiments of the present application;

Figure 29 is a schematic structural diagram of the first protection member provided on both sides of the first pole piece provided by some embodiments of the present application;

Figure 30 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (the first protective member and the third protective member are the same protective member);

Figure 31 is a schematic structural diagram of an electrode assembly (the first protective member covers the first ending end) provided by some embodiments of the present application;

Figure 32 is a schematic structural diagram of an electrode assembly (the second protective member covers the second ending end) provided by some embodiments of the present application;

Figure 33 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application (the first protective member covers the first ending end and the second protective member covers the second ending end);

Figure 34 is a schematic structural diagram of the first protective member covering the first ending end provided by some embodiments of the present application.

Icon: 10-box; 11-first part; 12-second part; 20-battery cell; 21-end cover; 22-electrode assembly; 221-first pole piece; 2211-first ending end; 2212- The first arc segment; 2213-the second arc segment; 2214-the fourth arc segment; 2215-the fifth arc segment; 222-the second pole piece; 2221-the second ending end; 2222-the third arc segment Section; 2223-sixth arc section; 223-isolation film; 224-protection piece; 2241-first protection piece; 22411-first section; 22412-second section; 22413-third section; 2242-second protection parts; 2243-the third protection part; 2244-the fourth protection part; 23-casing; 100-battery; 200-controller; 300-motor; 1000-vehicle.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are Apply for some of the embodiments, not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the technical field of this application; the terms used in the specification of this application are only for describing specific implementations. The purpose of the examples is not intended to limit the application; the terms "including" and "having" and any variations thereof in the description and claims of the application and the above description of the drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or priority relationship.

Reference in this application to "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the description of this application, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection", "connection" and "attachment" should be understood in a broad sense. For example, it can be a fixed connection, It can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

The term "and/or" in this application is just an association relationship describing related objects, indicating that there can be three relationships, for example, A and/or B, which can mean: A exists alone, A and B exist simultaneously, alone There are three situations B. In addition, the character "/" in this application generally indicates that the related objects are an "or" relationship.

In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of simplicity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length and width of the integrated device, are only illustrative illustrations and should not constitute any limitation to the present application. .

"Plural" appearing in this application means two or more (including two).

In this application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium-sulfur battery cell, a sodium lithium ion battery cell, a sodium ion battery cell or a magnesium ion battery cell, etc., in the embodiment of the present application There is no limit to this. The battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this. Battery cells are generally divided into three types according to packaging methods: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application are not limited to this.

The battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack. Batteries generally include a box for packaging one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

The battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode sheet, a negative electrode sheet and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector that is not coated with the positive electrode active material layer protrudes from the positive electrode current collector that is coated with the positive electrode active material layer. , the cathode current collector without coating the cathode active material layer serves as the cathode tab. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector that is not coated with the negative electrode active material layer protrudes from the negative electrode current collector that is coated with the negative electrode active material layer. , the negative electrode current collector that is not coated with the negative electrode active material layer is used as the negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon. In order to ensure that large currents can pass through without melting, the number of positive electrode lugs is multiple and stacked together, and the number of negative electrode lugs is multiple and stacked together. The material of the isolation film can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc. In addition, the electrode assembly may have a rolled structure or a laminated structure, and the embodiments of the present application are not limited thereto.

At present, judging from the development of the market situation, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in many fields such as military equipment and aerospace. As battery application fields continue to expand, its market demand is also expanding.

The development of battery technology must consider multiple design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery safety also needs to be considered. However, current battery cells using wound electrode assemblies are less safe.

The inventor further studied and found that for battery cells using wound electrode assemblies, during the cycle charge and discharge process of the battery cells, the electrode assembly will expand, and the pole pieces on the inner layer of the electrode assembly will gradually expand outward, and the electrode assembly will The outer pole piece cannot expand outward due to the characteristics of the winding structure and is bound by the battery cell shell. As the inner pole piece of the electrode assembly expands outward, the inner pole piece will contact with the outer pole piece. The ending end of the piece (the position of the ending end is equivalent to forming a step, which blocks the expansion of the inner pole piece) is squeezed and subjected to shearing force. The part of the pole piece adjacent to the ending end is directly squeezed by the ending end and is subjected to shearing force. The shear force is the largest and cracking may occur. When the pole piece cracks, there will be burrs and even metal debris at the fracture. These burrs and debris may pierce the isolation film, causing the positive and negative electrodes to overlap, causing the battery cells to short-circuit, causing the battery cells to catch fire or even explode.

In view of this, embodiments of the present application provide an electrode assembly. The electrode assembly includes a first pole piece, a second pole piece, an isolation film and a protective member. The polarity of the first pole piece and the second pole piece are opposite. The first pole piece, the isolation film and the second pole piece are wound along the winding direction to form an electrode assembly. The first pole piece has a first ending end. The protective piece is provided on the first pole piece and/or the second pole piece, and is configured to prevent the first ending end from contacting the portion of the first pole piece and the second pole piece adjacent to the first ending end.

The electrode assembly is provided with a protective piece. The protective piece can prevent the first ending end from contacting the parts of the first pole piece and the second pole piece adjacent to the first ending end, and reduce the shearing of the first ending end to this part. force, making this part less prone to strain, thereby reducing the risk of the pole piece cracking from this part, and also reducing the risk of burrs and debris generated at the cracking position piercing the isolation membrane, making the first pole piece and the second pole piece It is not easy to contact and short circuit, which improves the safety of the electrode assembly.

The technical solutions described in the embodiments of this application are applicable to batteries and electrical equipment using batteries.

Power-consuming devices can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys and power tools, etc. Spacecraft include airplanes, rockets, space shuttles, spaceships, etc.; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc.; electric tools include metal Cutting power tools, grinding power tools, assembly power tools and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and planers, etc. The embodiments of this application impose no special restrictions on the above electrical equipment.

In the following embodiments, for convenience of explanation, the electric equipment is the vehicle 1000 as an example.

Please refer to FIG. 1 , which is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. The battery 100 is disposed inside the vehicle 1000 , and the battery 100 may be disposed at the bottom, head, or tail of the vehicle 1000 . The battery 100 may be used to power the vehicle 1000 , for example, the battery 100 may serve as an operating power source for the vehicle 1000 . The vehicle 1000 may also include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to provide power to the motor 300 , for example, for starting, navigating and driving the vehicle 1000 .

In some embodiments of the present application, the battery 100 can not only be used as an operating power source for the vehicle 1000 , but also can be used as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .

Please refer to FIG. 2 , which is an exploded view of the battery 100 provided by some embodiments of the present application. The battery 100 includes a case 10 and battery cells 20 , and the battery cells 20 are accommodated in the case 10 . Among them, the box 10 is used to provide an accommodation space for the battery cells 20, and the box 10 can adopt a variety of structures. In some embodiments, the box 10 may include a first part 11 and a second part 12 , the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a space for accommodating the battery cells 20 of accommodation space. The second part 12 may be a hollow structure with one end open, and the first part 11 may be a plate-like structure. The first part 11 covers the open side of the second part 12 so that the first part 11 and the second part 12 jointly define a receiving space. ; The first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 is covered with the open side of the second part 12. Of course, the box 10 formed by the first part 11 and the second part 12 can be in various shapes, such as cylinder, rectangular parallelepiped, etc.

In the battery 100, there may be a plurality of battery cells 20, and the plurality of battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that the plurality of battery cells 20 are connected in series and in parallel. The plurality of battery cells 20 can be directly connected in series or in parallel or mixed together, and then the whole composed of the plurality of battery cells 20 can be accommodated in the box 10 ; of course, the battery 100 can also be a plurality of battery cells 20 First, the battery modules are connected in series, parallel, or mixed to form a battery module, and then multiple battery modules are connected in series, parallel, or mixed to form a whole, and are accommodated in the box 10 . The battery 100 may also include other structures. For example, the battery 100 may further include a bus component for realizing electrical connections between multiple battery cells 20 .

Each battery cell 20 may be a secondary battery cell or a primary battery cell; it may also be a lithium-sulfur battery cell, a sodium-ion battery cell or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes.

Please refer to FIG. 3 , which is an exploded structural diagram of a battery cell 20 provided in some embodiments of the present application. The battery cell 20 refers to the smallest unit that constitutes the battery 100 . As shown in FIG. 3 , the battery cell 20 includes an end cover 21 , an electrode assembly 22 , a case 23 and other functional components.

The end cap 21 refers to a component that covers the opening of the case 23 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 can be adapted to the shape of the housing 23 to fit the housing 23 . Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 21 is less likely to deform when subjected to extrusion and collision, so that the battery cell 20 can have higher durability. Structural strength and safety performance can also be improved. The end cap 21 may be provided with functional components such as electrode terminals (not shown in the figure). The electrode terminals may be used to electrically connect with the electrode assembly 22 for outputting or inputting electrical energy from the battery cell 20 . The end cap 21 can also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiment of the present application. In some embodiments, an insulating member may also be provided inside the end cover 21 , and the insulating member may be used to isolate the electrical connection components in the housing 23 from the end cover 21 to reduce the risk of short circuit. For example, the insulating member may be plastic, rubber, etc.

The housing 23 is a component used to cooperate with the end cover 21 to form an internal environment of the battery cell 20 , wherein the formed internal environment can be used to accommodate the electrode assembly 22 , electrolyte, and other components. The housing 23 and the end cover 21 may be independent components, and an opening may be provided on the housing 23. The end cover 21 covers the opening at the opening to form the internal environment of the battery cell 20. Without limitation, the end cover 21 and the housing 23 can also be integrated. Specifically, the end cover 21 and the housing 23 can form a common connection surface before other components are put into the housing. When it is necessary to encapsulate the inside of the housing 23 When, the end cover 21 covers the housing 23 again. The housing 23 can be of various shapes and sizes, such as rectangular parallelepiped, cylinder, hexagonal prism, etc. Specifically, the shape of the housing 23 can be determined according to the specific shape and size of the electrode assembly 22 . The housing 23 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiment of the present application.

The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 22 may be contained within the housing 23 . The electrode assembly 22 is mainly formed by winding or stacking positive electrode sheets and negative electrode sheets, and an isolation film is usually provided between the positive electrode sheets and the negative electrode sheets. The portions of the positive electrode sheet and the negative electrode sheet that contain active material constitute the main body of the electrode assembly 22 , and the portions of the positive electrode sheet and the negative electrode sheet that do not contain active material each constitute tabs. The positive electrode tab and the negative electrode tab can be located together at one end of the main body or respectively located at both ends of the main body. During the charging and discharging process of the battery 100, the positive active material and the negative active material react with the electrolyte, and the tabs are connected to the electrode terminals to form a current loop.

Please refer to Figures 4, 5 and 6. Figure 4 shows the electrode assembly 22 provided by some embodiments of the present application (along the winding direction, the second ending end 2221 exceeds the first ending end 2211, and is inside the first ending end 2211. Structural diagram of setting the protective member 224). Figure 5 is a schematic structural diagram of the electrode assembly 22 provided by some embodiments of the present application (along the winding direction, the second ending end 2221 exceeds the first ending end 2211, and a protective member 224 is provided outside the first ending end 2211). Figure 6 is a schematic structural diagram of the electrode assembly 22 provided by some embodiments of the present application (along the winding direction, the second ending end 2221 exceeds the first ending end 2211, and protective members 224 are provided both inside and outside the first ending end 2211). . The embodiment of the present application provides an electrode assembly 22. The electrode assembly 22 includes a first pole piece 221, a second pole piece 222, an isolation film 223 and a protective member 224. The first pole piece 221 and the second pole piece 222 have opposite polarities. The first pole piece 221, the isolation film 223 and the second pole piece 222 are wound along the winding direction to form the electrode assembly 22. The first pole piece 221 has a first ending end 2211. The protective member 224 is provided on the first pole piece 221 and/or the second pole piece 222 and is configured to prevent the first ending end 2211 from being adjacent to the first ending end 2211 of the first pole piece 221 and the second pole piece 222 . contact parts.

One of the first pole piece 221 and the second pole piece 222 is a positive pole piece, and the other one is a negative pole piece. For example, when the first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece. For another example, when the first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece.

The isolation film 223 is an insulating structure disposed between the first pole piece 221 and the second pole piece 222. The isolation film 223 is used to insulate the first pole piece 221 and the second pole piece 222 to prevent the first pole piece 221 from Contact with the second pole piece 222 and cause a short circuit.

The first ending end 2211 is the winding end of the first pole piece 221. Along the winding direction, the first ending end 2211 is located at the end of the first pole piece 221. The first ending end 2211 is usually close to the outside of the electrode assembly 22. layer. The first pole piece 221 also has a first starting end, which serves as a starting point for winding the first pole piece 221 and is usually located inside the electrode assembly 22 .

The protective member 224 is a component used to separate the first end end 2211 from the "portions of the first pole piece 221 and the second pole piece 222 adjacent to the first end end 2211" to protect the "first pole piece 221 and the second pole piece 222." The portion of the diode piece 222 adjacent to the first ending end 2211 "serves as a protective component. During the cycle charge and discharge process of the battery cell 20, the protective member 224 will first contact the first ending end 2211 and bear the shearing force of the first ending end 2211. After the shearing force is dispersed by the protecting member 224, it acts on the "first ending end". The shearing force of the portion of the pole piece 221 and the second pole piece 222 adjacent to the first ending end 2211 is smaller, so it is less likely to cause cracking in this portion.

“The portion of the first pole piece 221 and the second pole piece 222 adjacent to the first ending end 2211” refers to the portion of the first pole piece 221 and the second pole piece 222 that is adjacent to the first end 2211 along the radial direction of the electrode assembly 22. A portion of one of the ending ends 2211 is close to the first ending end 2211. For example, please refer to Figure 4, the second pole piece 222 has a second ending end 2221, the second pole piece 222 is partially located outside the first ending end 2211, and the second ending end 2221 exceeds the first ending end along the winding direction. 2211. At this time, "the portion of the first pole piece 221 and the second pole piece 222 adjacent to the first ending end 2211" is the portion of the second pole piece 222 close to the first ending end 2211 (along the direction of the electrode assembly 22 In the radial direction, there is a second pole piece 222 between the first pole piece 221 closest to the first ending end 2211 and the first ending end 2211, so the first pole piece 221 cannot be counted as being closest to the first ending end 2211. adjacent pole pieces). The second pole piece 222 has two parts close to the first ending end 2211 , one is located inside the first ending end 2211 , and the other is located outside the first ending end 2211 . Please refer to FIG. 4 , the protective member 224 may be provided only on the portion located inside the first ending end 2211 . Please refer to FIG. 5 , the protective member 224 may be provided only on the portion located outside the first ending end 2211 . Please refer to FIG. 6 , the protective member 224 can be disposed on both the portion located inside the first ending end 2211 and the portion located outside the first ending end 2211 .

For another example, please refer to Figure 7, which shows the electrode assembly 22 provided by some embodiments of the present application (along the winding direction, the first ending end 2211 exceeds the second ending end 2221, and a protective member is provided inside the first ending end 2211 224) structural diagram. The first pole piece 221 is partially located outside the second ending end 2221, and the first ending end 2211 exceeds the second ending end 2221 along the winding direction. At this time, "the portion of the first pole piece 221 and the second pole piece 222 adjacent to the first ending end 2211" is the portion of the first pole piece 221 close to the first ending end 2211 (along the direction of the electrode assembly 22 Radially, there is a first pole piece 221 between the second pole piece 222 closest to the first ending end 2211 and the first ending end 2211. Therefore, the second pole piece 222 cannot be counted as being closest to the first ending end 2211. adjacent pole pieces). There is only one portion of the first pole piece 221 close to the first ending end 2211 . Therefore, along the radial direction of the electrode assembly 22, the protective member 224 blocks this part to protect the part, separate the part from the first ending end 2211, and prevent the first ending end 2211 from contacting the part and applying force to the part. Shear force.

The electrode assembly 22 is provided with a protective member 224. The protective member 224 can prevent the first ending end 2211 from contacting the parts of the first pole piece 221 and the second pole piece 222 adjacent to the first ending end 2211, thereby reducing the first ending end 2211. The shear force exerted by end 2211 on this part makes this part less likely to strain, thereby reducing the risk of the pole piece cracking from this part, and also reducing the risk of burrs and debris generated at the cracking location piercing the isolation membrane 223, making The first pole piece 221 and the second pole piece 222 are not easily exposed to short circuit, which improves the safety of the electrode assembly 22 .

Referring to FIG. 7 , in some embodiments, the protective member 224 includes a first protective member 2241 . The second pole piece 222 has a second ending end 2221. The first pole piece 221 is partially located outside the second ending end 2221, and the first ending end 2211 exceeds the second ending end 2221 along the winding direction. The first protection member 2241 is provided on the first pole piece 221 to prevent the first tail end 2211 from contacting the adjacent first pole piece 221.

The first pole piece 221 may be a negative pole piece, the second pole piece 222 may be a positive pole piece, and the first ending end 2211 exceeds the second ending end 2221 along the winding direction, so that the first pole piece 221 covers the second pole piece 222 , to avoid lithium precipitation. At this time, "the portion of the first pole piece 221 and the second pole piece 222 adjacent to the first ending end 2211" is the portion of the first pole piece 221 close to the first ending end 2211 (along the direction of the electrode assembly 22 Radially, there is a first pole piece 221 between the second pole piece 222 closest to the first ending end 2211 and the first ending end 2211. Therefore, the second pole piece 222 cannot be counted as being closest to the first ending end 2211. adjacent pole pieces). The first protective member 2241 can separate the first end end 2211 from the first pole piece 221 adjacent to the first end end 2211 (that is, the portion of the first pole piece 221 close to the first end end 2211) to prevent The two are in contact, thereby reducing the risk of cracking of the first pole piece 221.

Since the first pole piece 221 is partially located outside the second ending end 2221, the first pole piece 221 is adjacent to the first ending end 2211 of the first pole piece 221 and the second pole piece 222. Therefore, the first protection The member 2241 is provided on the first pole piece 221, which can more easily separate the first ending end 2211 from the adjacent first pole piece 221, and reduce the impact of the first ending end 2211 on the adjacent first pole piece 221. Shearing force prevents the first pole piece 221 from cracking, thereby improving the safety of the electrode assembly 22 .

Referring to FIG. 7 , in some embodiments, along the radial direction of the electrode assembly 22 , the first pole piece 221 includes a plurality of arc segments, and the projection of the first end end 2211 is located within the projection of the arc segments. The outermost arc segment among the plurality of arc segments is the first arc segment 2212, and a first protective member 2241 is provided on the outer surface of the first arc segment 2212.

The arc segment may be an arc portion on the first pole piece 221 with a line connecting the first ending end 2211 and the winding center as the axis of symmetry and a length less than or equal to 10 mm. In order to confirm the range of the arc segment, you can also project the first protective member 2241 on the first pole piece 221 along the radial direction of the electrode assembly 22, and use the range defined by the projection on the first pole piece 221 as a circular arc. segment (the part of the first pole piece 221 defined by two dotted lines in the figure is the arc segment).

The first arc segment 2212 is the outermost arc segment among the plurality of arc segments. The first arc segment 2212 is the part that is most likely to crack due to shearing force in contact with the first ending end 2211 . Therefore, a first protective member 2241 is provided on the outer surface of the first arc segment 2212 to protect the first arc segment 2212.

The first arc segment 2212 is the arc segment closest to the first ending end 2211 among the multiple arc segments, and is also the arc segment most susceptible to the shearing force of the first ending end 2211. Therefore, the first protective member 2241 is provided on the outer surface of the first arc segment 2212 to protect the first arc segment 2212, reduce the risk of cracking of the first arc segment 2212, and improve the safety of the electrode assembly 22.

Please refer to FIG. 8 , which is a schematic structural diagram of the electrode assembly 22 provided by some embodiments of the present application (first protection members 2241 are provided on both sides of the first arc segment 2212 ). In some embodiments, along the radial direction of the electrode assembly 22 , a first protective member 2241 is provided on the inner surface of the first arc segment 2212 .

Along the radial direction of the electrode assembly 22 , the first arc segment 2212 has an outer surface and an inner surface that are oppositely arranged. The outer surface faces the first ending end 2211, and the inner surface faces away from the first ending end 2211. First protection members 2241 are provided on both the outer surface and the inner surface of the first arc segment 2212. In other words, along the radial direction of the electrode assembly 22 , first protection members 2241 are provided on both sides of the first arc segment 2212 .

By also providing the first protective member 2241 on the inner surface of the first arc segment 2212, on the one hand, the tensile strength of the first arc segment 2212 can be increased, making the first arc segment 2212 less likely to be broken when expanding. On the other hand, if the first arc section 2212 cracks, the newly generated step surface at the cracked position will be blocked by the first protection member 2241 provided inside the first arc section 2212, thereby preventing the newly generated step surface from being located on the first The arc segment inside the arc segment 2212 applies shearing force to reduce the risk of cracking in the arc segment located inside the first arc segment 2212 .

Please refer to FIG. 9 , which is a schematic structural diagram of the electrode assembly 22 (the first protective member 2241 is provided on one side of the second arc segment 2213) provided by some embodiments of the present application. In some embodiments, the arc segment located inside the first arc segment 2212 among the plurality of arc segments is the second arc segment 2213 , and at least one second arc segment 2213 is provided with a first protection member 2241 .

Along the radial direction of the electrode assembly 22 , the second arc segment 2213 specifically refers to the arc segment located inside the first arc segment 2212 . "At least one second arc segment 2213 is provided with the first protective member 2241" includes one second arc segment 2213 is provided with the first protective member 2241, two second arc segments 2213 are provided with the first protective member 2241, and two second arc segments 2213 are provided with the first protective member 2241. More than two second arc segments 2213 are provided with first protection members 2241.

By arranging the first protection member 2241 on at least one second arc segment 2213, on the one hand, the tensile strength of the second arc segment 2213 can be increased, making the second arc segment 2213 less likely to be broken during expansion (due to production reasons). Due to the influence of fluctuations during the process, the mechanical properties of the second arc segment 2213 at different positions are different, and the second arc segment 2213 may be broken before the first arc segment 2212). On the other hand, if the first arc segment 2212 cracks, a new step surface will be generated at the cracking position, and the new step surface will act on the second arc segment 2213, which will cause the second arc segment 2213 to crack. The first protective member 2241 provided on the arc segment 2213 can protect the second arc segment 2213, reduce the stress of the newly generated step on the second arc segment 2213, and reduce the risk of cracking in the second arc segment 2213.

Please refer to FIG. 10 , which is a schematic structural diagram of the electrode assembly 22 (with first protection members 2241 provided on both sides of the second arc segment 2213 ) provided by some embodiments of the present application. In some embodiments, first protection members 2241 are provided on both sides of at least one second arc segment 2213 along the radial direction of the electrode assembly 22 .

"At least one second arc segment 2213 is provided with first protection members 2241 on both sides" includes one second arc segment 2213 with first protection members 2241 on both sides and two second arc segments 2213. First protection members 2241 are provided on both sides, and first protection members 2241 are provided on both sides of more than two second arc segments 2213 .

Along the radial direction of the electrode assembly 22 , first protection members 2241 are provided on both sides of the second arc segment 2213 . This also means that along the radial direction of the electrode assembly 22 , the second arc segment 2213 faces the first arc segment. A first protective member 2241 is provided on the surface of the segment 2212, and a first protective member 2241 is also provided on the surface of the second arc segment 2213 away from the first arc segment 2212.

By disposing the second protection members 2242 on both sides of the second arc segment 2213, on the one hand, the tensile strength of the second arc segment 2213 can be increased, making the second arc segment 2213 less likely to be broken when expanding. On the other hand, if the second arc section 2213 cracks, the newly generated step surface at the cracked position will be blocked by the second protection member 2242 provided inside the cracked second arc section 2213, thereby preventing the newly generated step surface from facing the cracked second arc section 2213. The arc segment located inside the cracked second arc segment 2213 exerts shear force, thereby reducing the risk of cracking in the arc segment located inside the cracked second arc segment 2213.

In some embodiments, the number of arc segments exceeds 5. Along the radial direction of the electrode assembly 22, first protection members 2241 are provided on at least five continuously arranged arc segments from outside to inside.

Here, the arc segment includes a first arc segment 2212 and a second arc segment 2213. Along the radial direction of the electrode assembly 22, there is one first arc segment 2212 and at least four second arc segments 2213 from outside to inward. A first protective member 2241 is provided. Continuous arrangement means that there are no other first arc segments 2212 or second arc segments 2213 between two adjacent arc segments where the first protective member 2241 is disposed.

It has been found through actual tests that the five circular arc segments continuously arranged from outside to inside along the radial direction of the electrode assembly 22 are more likely to crack. Therefore, at least five circular arc segments continuously arranged from outside to inside along the radial direction of the electrode assembly 22 A first protective piece 2241 is provided on the arc segment to protect it and reduce the risk of cracking.

Please refer to FIG. 11 , which is a schematic structural diagram of the electrode assembly 22 (the second protective member 2242 is provided on one side of the third arc segment 2222) provided by some embodiments of the present application. In some embodiments, the protective member 224 also includes a second protective member 2242. Along the radial direction of the electrode assembly 22 , the second pole piece 222 includes a plurality of third arc segments 2222 , and the projection of the first end end 2211 is located within the projection of the third arc segments 2222 . At least one third arc segment 2222 is provided with a second protection member 2242.

The third arc segment 2222 may be an arc portion on the second pole piece 222 with a line connecting the first ending end 2211 and the winding center as the axis of symmetry and a length less than or equal to 10 mm. In order to confirm the range of the third arc segment 2222, the second protective member 2242 can also be projected on the second pole piece 222 along the radial direction of the electrode assembly 22, and the range defined by the projection on the second pole piece 222 can be As the third arc segment 2222 (the part of the second pole piece 222 defined by two dotted lines in the figure is the third arc segment 2222).

During the cycle charge and discharge process of the battery cell 20 , the first arc segment 2212 may crack. At this time, the step formed at the cracked position of the first arc segment 2212 will exert shearing force on the third arc segment 2222 . Therefore, , a second protective member 2242 is provided on the third arc segment 2222 to protect the third arc segment 2222.

By disposing the second protection member 2242 on at least one third arc segment 2222, on the one hand, the tensile strength of the third arc segment 2222 can be increased, making the third arc segment 2222 less likely to be broken during expansion (due to production reasons). Due to the influence of fluctuations during the process, the mechanical properties of the third arc segment 2222 located at different positions are different, and the third arc segment 2222 may be broken). On the other hand, if the third arc segment 2222 cracks, a new step surface will be generated at the cracking position, and the new step surface acting on the second arc segment 2213 will cause the second arc segment 2213 to crack. The second protective member 2242 provided on the arc segment 2222 can protect the third arc segment 2222 and reduce the risk of cracking in the third arc segment 2222. In addition, when the second arc segment 2213 or the first arc segment 2212 cracks, the second protection member 2242 can also reduce the shear force of the newly generated step surface on the third arc segment 2222, so as to reduce the third arc segment 2222. There is a risk of cracking in arc segment 2222.

Please refer to FIG. 12 , which is a schematic structural diagram of the electrode assembly 22 (with second protection members 2242 provided on both sides of the third arc segment 2222 ) provided by some embodiments of the present application. In some embodiments, along the radial direction of the electrode assembly 22, second protection members 2242 are provided on both sides of at least one third arc segment 2222.

"At least one third arc segment 2222 is provided with second protection members 2242 on both sides" includes one third arc segment 2222 with second protection members 2242 on both sides and two third arc segments 2222. Second protection members 2242 are provided on both sides, and second protection members 2242 are provided on both sides of more than two third arc segments 2222 .

Along the radial direction of the electrode assembly 22 , second protection members 2242 are provided on both sides of the third arc segment 2222 . This also means that along the radial direction of the electrode assembly 22 , the third arc segment 2222 faces the first arc segment. A second protective member 2242 is provided on the surface of the segment 2212, and a second protective member 2242 is also provided on the surface of the third arc segment 2222 away from the first arc segment 2212.

By disposing the second protection members 2242 on both sides of the third arc segment 2222, the tensile strength of the third arc segment 2222 can be increased, making the third arc segment 2222 less likely to be broken when expanding. If the third arc segment 2222 cracks, the newly generated step surface at the cracked position will be blocked by the second protection member 2242 provided inside the third arc segment 2222, thereby preventing the newly generated step surface from being located in the third arc segment 2222. The inner arc segment exerts shear force to reduce the risk of cracking in the arc segment located inside the third arc segment 2222.

Please refer to Figures 13 and 14. Figure 13 is a schematic structural diagram of the electrode assembly 22 (the first protective member 2241 covers the first arc segment 2212) provided by some embodiments of the present application. Figure 14 is a schematic structural diagram of the first protective member 2241 covering the first arc segment 2212 provided by some embodiments of the present application. In some embodiments, along the radial direction of the electrode assembly 22 , the first pole piece 221 includes a plurality of arc segments, and the projection of the first end end 2211 is located in the arc segments. The outermost arc segment among the plurality of arc segments is the first arc segment 2212 , and the first protective member 2241 covers the first arc segment 2212 .

"The first protective member 2241 covers the first arc segment 2212" means that the first protective member 2241 completely covers the outer surface of the first arc segment 2212 (as shown in Figure 14, the four surfaces of the first arc segment 2212 are covered by the first protective member 2241, which has a better protective effect on the first protective member 2241). "The first protective member 2241 covers the first arc segment 2212" can also be understood to mean that the first protective member 2241 is circumferentially arranged around the first arc segment 2212.

By arranging the first protective member 2241 to cover the first arc segment 2212, while increasing the tensile strength of the first arc segment 2212, even if the first arc segment 2212 cracks, the new steps generated will be blocked by the first protective member. 2241 shielding will not have much impact on other arc segments located inside the first arc segment 2212. The coating method can better protect the first arc segment 2212 and improve the safety of the electrode assembly 22 .

Please refer to FIG. 15 , which is a schematic structural diagram of the electrode assembly 22 (the first protective member 2241 covers the second arc segment 2213 ) provided by some embodiments of the present application. In some embodiments, the arc segment located inside the first arc segment 2212 among the plurality of arc segments is the second arc segment 2213 , and at least one second arc segment 2213 is covered by the first protective member 2241 .

"At least one second arc segment 2213 is covered by a first protective member 2241" includes one second arc segment 2213 being covered by a first protective member 2241, and two second arc segments 2213 being covered by two first protective members 2241. The protective member 2241 covers and the two or more second arc segments 2213 are respectively covered by the two or more first protective members 2241 . There is a one-to-one correspondence between the second arc segment 2213 and the first protective member 2241 covering the second arc segment 2213.

By arranging the first protective member 2241 to cover the second arc segment 2213, while increasing the tensile strength of the second arc segment 2213, even if the second arc segment 2213 cracks, the new steps generated will be blocked by the first protective member. 2241 shielding will not have much impact on other arc segments located inside the second arc segment 2213. The coating method can better protect the second arc segment 2213 and improve the safety of the electrode assembly 22 .

Please refer to FIG. 16 , which is a schematic structural diagram of the electrode assembly 22 (the second protective member 2242 covers the third arc segment 2222 ) provided by some embodiments of the present application. In some embodiments, protector 224 includes second protector 2242. Along the radial direction of the electrode assembly 22 , the second pole piece 222 includes a plurality of third arc segments 2222 , and the projection of the first end end 2211 is located within the projection of the third arc segments 2222 . At least one third arc segment 2222 is covered by the second protective member 2242.

At least one third arc segment 2222 is covered by the second protective member 2242, including one third arc segment 2222 covered by a second protective member 2242, and two third arc segments 2222 respectively covered by two second protective members. 2242 and two or more third arc segments 2222 are respectively covered by two or more second protection members 2242. There is a one-to-one correspondence between the third arc segment 2222 and the second protection member 2242.

By arranging the second protective member 2242 to cover the third arc segment 2222, while increasing the tensile strength of the third arc segment 2222, even if the third arc segment 2222 cracks, the new steps generated will be blocked by the second protective member. 2242 shielding will not have much impact on other arc segments located inside the third arc segment 2222. The coating method can better protect the third arc segment 2222 and improve the safety of the electrode assembly 22 .

Please refer to FIG. 17 , which is a schematic structural diagram of the electrode assembly 22 provided by some embodiments of the present application (the portion of the first pole piece 221 located outside the second ending end 2221 is provided with a third protective member 2243 ). In some embodiments, the protective member 224 further includes a third protective member 2243, which is used to prevent the second tail end 2221 from contacting the first pole piece 221.

The first pole piece 221 is partially located outside the second ending end 2221, and the first ending end 2211 exceeds the second ending end 2221 along the winding direction. At this time, "the portion of the first pole piece 221 and the second pole piece 222 adjacent to the second ending end 2221" is the portion of the first pole piece 221 close to the second ending end 2221 (along the direction of the electrode assembly 22 In the radial direction, there is a first pole piece 221 between the second pole piece 222 closest to the second ending end 2221 and the second ending end 2221, so the second pole piece 222 cannot be counted as being closest to the second ending end 2221. adjacent pole pieces). During the cycle charging and discharging process of the battery cell 20 , this part is easily in contact with the second ending end 2221 and is subjected to the shearing force of the second ending end 2221 . Therefore, the third protection member 2243 is provided to prevent the second tail end 2221 from contacting the first pole piece 221, so as to protect this part.

Since the first pole piece 221 is partially located outside the second ending end 2221, the first pole piece 221 is adjacent to the second ending end 2221 of the first pole piece 221 and the second pole piece 222. Therefore, the third protection The member 2243 is provided on the first pole piece 221, which can more easily separate the second ending end 2221 from the adjacent first pole piece 221, and reduce the impact of the second ending end 2221 on the adjacent first pole piece 221. Shearing force prevents the first pole piece 221 from cracking, thereby improving the safety of the electrode assembly 22 .

Please refer to Figures 17, 18 and 19. Figure 18 is a schematic structural diagram of the electrode assembly 22 provided by some embodiments of the present application (the portion of the first pole piece 221 located inside the second ending end 2221 is provided with a third protective member 2243). . Figure 19 is a schematic structural diagram of the electrode assembly 22 provided by some embodiments of the present application (the portions of the first pole piece 221 located inside and outside the second ending end 2221 are both provided with third protection members 2243). In some embodiments, the portion of the first pole piece 221 located outside the second ending end 2221 and/or the portion of the first pole piece 221 located inside the second ending end 2221 is provided with a third protection member 2243 .

There are two parts of the first pole piece 221 close to the second ending end 2221 , one is located inside the second ending end 2221 , and the other is located outside the second ending end 2221 . Referring to FIG. 17 , the protective member 224 may be provided only on the portion located outside the second ending end 2221 . Please refer to FIG. 18 , the protective member 224 may be provided only on the portion located inside the second ending end 2221 . Please refer to FIG. 19 , the protective member 224 can be disposed on both the portion located inside the second ending end 2221 and the portion located outside the second ending end 2221 .

Both the part of the first pole piece 221 located outside the second ending end 2221 and the part of the first pole piece 221 located inside the second ending end 2221 may be affected by the shearing force of the second ending end 2221. Therefore, when the first pole piece 221 is located outside the second ending end 2221, The portion of 221 located outside the second ending end 2221 and the portion of the first pole piece 221 located inside the second ending end 2221 are provided with a third protective member 2243 to protect the first pole piece 221 and reduce the risk of cracking of the first pole piece 221 risk, providing the safety of the electrode assembly 22.

Referring to FIG. 19 , in some embodiments, along the radial direction of the electrode assembly 22 , the first pole piece 221 includes a fourth arc segment 2214 , and the projection of the second end end 2221 is located within the projection of the fourth arc segment 2214 . The fourth arc segment 2214 is adjacent to the second ending end 2221, and a third protective member 2243 is provided on a surface of the fourth arc segment 2214 facing the second ending end 2221.

The fourth arc segment 2214 may be an arc portion on the first pole piece 221 with a line connecting the second ending end 2221 and the winding center as the axis of symmetry and a length less than or equal to 10 mm. In order to confirm the range of the fourth arc segment 2214, the third protective member 2243 can also be projected on the first pole piece 221 along the radial direction of the electrode assembly 22, and the range defined by the projection on the first pole piece 221 As the fourth arc segment 2214 (as shown in the figure, the part of the first pole piece 221 defined by two dotted lines located on both sides of the second ending end 2221 is the fourth arc segment 2214). It should be noted that the fourth arc segment 2214 is the arc portion of the first pole piece 221 close to the second ending end 2221. There is no other first pole piece between the fourth arc segment 2214 and the second ending end 2221. 221 or the second pole piece 222.

The fourth arc segment 2214 is the position on the first pole piece 221 that is most susceptible to the shear force of the second ending end 2221 and causes cracking. By setting a third arc segment on the surface of the fourth arc segment 2214 facing the second ending end 2221 The protective member 2243 is used to protect the fourth arc segment 2214 and reduce the risk of cracking of the first pole piece 221 due to the shear force of the second ending end 2221.

Please refer to FIG. 20 , which is a schematic structural diagram of the electrode assembly 22 provided by some embodiments of the present application (third protection members 2243 are provided on both sides of the fourth arc segment 2214 ). In some embodiments, third protection members 2243 are provided on both sides of the fourth arc segment 2214 along the radial direction of the electrode assembly 22 .

Along the radial direction of the electrode assembly 22 , third protectors 2243 are provided on both sides of the fourth arc segment 2214 . This also means that along the radial direction of the electrode assembly 22 , the fourth arc segment 2214 faces the second ending end. A third protective member 2243 is provided on the surface of 2221, and a third protective member 2243 is also provided on the surface of the fourth arc segment 2214 away from the second ending end 2221.

By disposing third protection members 2243 on both sides of the fourth arc segment 2214, on the one hand, the tensile strength of the fourth arc segment 2214 can be increased, making the fourth arc segment 2214 less likely to be broken when expanded. On the other hand, if the fourth arc segment 2214 cracks, the newly generated step surface at the cracked position will be blocked by the third protective member 2243 provided on the fourth arc segment 2214 away from the second ending end 2221, thereby preventing the newly generated step surface. The step surface exerts shear force on the arc segment located inside the cracked fourth arc segment 2214, thereby reducing the risk of cracking in the arc segment located inside the cracked fourth arc segment 2214.

Please refer to FIG. 21 , which is a schematic structural diagram of the electrode assembly 22 (a third protective member 2243 is provided on one side of the fifth arc segment 2215) provided by some embodiments of the present application. In some embodiments, along the radial direction of the electrode assembly 22 , the first pole piece 221 includes a fifth arc segment 2215 , and the projection of the second end end 2221 is located within the projection of the fifth arc segment 2215 . The fifth arc segment 2215 is located inside the fourth arc segment 2214. At least one fifth arc segment 2215 is provided with a third protection member 2243.

The fifth arc segment 2215 may be an arc portion on the first pole piece 221 with a line connecting the second ending end 2221 and the winding center as the axis of symmetry, a length less than or equal to 10 mm, and located inside the fourth arc segment 2214. In order to confirm the range of the fifth arc segment 2215, the third protective member 2243 can also be projected on the first pole piece 221 along the radial direction of the electrode assembly 22, and the projection is defined on the first pole piece 221. The range located inside the fourth arc segment 2214 is regarded as the fifth arc segment 2215 (in the figure, the first pole piece 221 is defined by two dotted lines located on both sides of the second ending end 2221, and is located inside the fourth arc segment 2214. The part is the fifth arc segment 2215).

By arranging the third protective member 2243 on at least one fifth arc segment 2215, on the one hand, the tensile strength of the fifth arc segment 2215 can be increased, making the fifth arc segment 2215 less likely to be broken during expansion (due to production reasons). Due to the influence of fluctuations during the process, the fifth arc segment 2215 located at different positions has different mechanical properties, and the fifth arc segment 2215 may be broken before the fourth arc segment 2214). On the other hand, if the fourth arc segment 2214 cracks, a new step surface will be generated at the cracking position, and the new step surface acting on the fifth arc segment 2215 will cause the fifth arc segment 2215 to crack. The third protective member 2243 provided on the arc segment 2215 can protect the fifth arc segment 2215, reduce the stress of the newly generated step on the fifth arc segment 2215, and reduce the risk of cracking in the fifth arc segment 2215.

Please refer to FIG. 22 , which is a schematic structural diagram of the electrode assembly 22 (with third protection members 2243 provided on both sides of the fifth arc segment 2215 ) provided by some embodiments of the present application. In some embodiments, third protection members 2243 are provided on both sides of at least one fifth arc segment 2215 along the radial direction of the electrode assembly 22 .

By disposing third protection members 2243 on both sides of the fifth arc segment 2215, on the one hand, the tensile strength of the fifth arc segment 2215 can be increased, making the fifth arc segment 2215 less likely to be broken when expanded. On the other hand, if the fifth arc segment 2215 cracks, the newly generated step surface at the crack position will be blocked by the third protection member 2243 provided inside the fifth arc segment 2215, thereby preventing the newly generated step surface from being located at the crack position. The arc segment inside the fifth arc segment 2215 exerts a shearing force to reduce the risk of cracking in the arc segment located inside the cracked fifth arc segment 2215.

Please refer to FIG. 23 , which is a schematic structural diagram of the electrode assembly 22 (a third protective member 2243 is provided on one side of the sixth arc segment 2223) provided by some embodiments of the present application. In some embodiments, the protective member 224 further includes a fourth protective member 2244. Along the radial direction of the electrode assembly 22 , the second pole piece 222 includes a plurality of sixth arc segments 2223 , and the projection of the second end end 2221 is located within the projection of the sixth arc segments 2223 . At least one sixth arc segment 2223 is provided with a fourth protection member 2244.

The sixth arc segment 2223 may be an arc portion on the second pole piece 222 with a line connecting the second ending end 2221 and the winding center as the axis of symmetry and a length less than or equal to 10 mm. In order to confirm the range of the sixth arc segment 2223, the fourth protective member 2244 can also be projected on the second pole piece 222 along the radial direction of the electrode assembly 22, and the range defined by the projection on the second pole piece 222 can be As the sixth arc segment 2223 (as shown in the figure, the portion of the second pole piece 222 defined by two dotted lines located on both sides of the second ending end 2221 is the sixth arc segment 2223).

During the cycle charge and discharge process of the battery cell 20, the fourth arc segment 2214 may crack. At this time, the step formed at the crack position of the fourth arc segment 2214 will exert shearing force on the sixth arc segment 2223. Therefore, , a fourth protective member 2244 is provided on the sixth arc segment 2223 to protect the sixth arc segment 2223.

By disposing the fourth protective member 2244 on at least one sixth arc segment 2223, on the one hand, the tensile strength of the sixth arc segment 2223 can be increased, making the sixth arc segment 2223 less likely to be broken during expansion (due to production reasons). Due to the influence of fluctuations during the process, the mechanical properties of the sixth arc segment 2223 located at different positions are different, and the sixth arc segment 2223 may be broken). On the other hand, if the sixth arc segment 2223 cracks, a new step surface will be generated at the cracking position, and the new step surface acting on the fifth arc segment 2215 will cause the fifth arc segment 2215 to crack. The fourth protective member 2244 provided on the arc segment 2223 can protect the sixth arc segment 2223 and reduce the risk of cracking in the sixth arc segment 2223. In addition, when the fourth arc segment 2214 or the fifth arc segment 2215 cracks, the fourth protective member 2244 can also reduce the shear force of the sixth arc segment 2223 from the newly generated step surface, so as to reduce the shear force of the sixth arc segment 2223. There is a risk of cracking in arc segment 2223.

Please refer to FIG. 24 , which is a schematic structural diagram of the electrode assembly 22 (with third protection members 2243 provided on both sides of the sixth arc segment 2223 ) provided by some embodiments of the present application. In some embodiments, along the radial direction of the electrode assembly 22 , fourth protection members 2244 are provided on both sides of at least one sixth arc segment 2223 .

"At least one sixth arc segment 2223 is provided with fourth protection members 2244 on both sides" includes one sixth arc segment 2223 with fourth protection members 2244 on both sides and two sixth arc segments 2223. Fourth protective members 2244 are provided on both sides, and fourth protective members 2244 are provided on both sides of more than two sixth arc segments 2223 .

Along the radial direction of the electrode assembly 22 , fourth protective members 2244 are provided on both sides of the sixth arc segment 2223 . This also means that along the radial direction of the electrode assembly 22 , the sixth arc segment 2223 faces the second ending end. A fourth protective member 2244 is provided on the surface of 2221, and a fourth protective member 2244 is also provided on the surface of the sixth arc segment 2223 away from the second ending end 2221.

By disposing the fourth protection members 2244 on both sides of the sixth arc segment 2223, on the one hand, the tensile strength of the sixth arc segment 2223 can be increased, making the sixth arc segment 2223 less likely to be broken when expanding. On the other hand, if the sixth arc segment 2223 cracks, the newly generated step surface at the cracked position will be blocked by the fourth protective member 2244 provided on the side of the sixth arc segment 2223 away from the second ending end 2221, thereby preventing new steps. The generated step surface exerts shear force on the arc segment located inside the cracked sixth arc segment 2223, thereby reducing the risk of cracking in the arc segment located inside the cracked sixth arc segment 2223.

Please refer to FIG. 25 , which is a schematic structural diagram of the electrode assembly 22 (the third protective member 2243 covers the fourth arc segment 2214 ) provided by some embodiments of the present application. In some embodiments, along the radial direction of the electrode assembly 22, the first pole piece 221 includes a fourth arc segment 2214, the projection of the second end end 2221 is located within the projection of the fourth arc segment 2214, and the fourth arc segment 2214 is adjacent to the second ending end 2221. The third protective member 2243 covers the fourth arc segment 2214.

By arranging the third protective member 2243 to cover the fourth arc segment 2214, while increasing the tensile strength of the fourth arc segment 2214, even if the fourth arc segment 2214 cracks, the new steps generated will be blocked by the third protective member. 2243 shielding will not have much impact on other arc segments located inside the fourth arc segment 2214. The coating method can better protect the fourth arc segment 2214 and improve the safety of the electrode assembly 22 .

Please refer to FIG. 26 , which is a schematic structural diagram of the electrode assembly 22 (the third protective member 2243 covers the fifth arc segment 2215 ) provided by some embodiments of the present application. In some embodiments, along the radial direction of the electrode assembly 22, the first pole piece 221 includes a fifth arc segment 2215, the projection of the second end end 2221 is located within the projection of the fifth arc segment 2215, and the fifth arc segment 2215 is located inside the fourth arc segment 2214. At least one fifth arc segment 2215 is covered by the third protective member 2243.

By arranging the third protective member 2243 to cover the fifth arc segment 2215, while increasing the tensile strength of the fifth arc segment 2215, even if the fifth arc segment 2215 cracks, the new steps generated will be blocked by the third protective member. 2243 shielding will not have much impact on other arc segments located inside the fifth arc segment 2215. The coating method can better protect the fifth arc segment 2215 and improve the safety of the electrode assembly 22 .

Please refer to FIG. 27 , which is a schematic structural diagram of the electrode assembly 22 (the fourth protective member 2244 covers the sixth arc segment 2223 ) provided by some embodiments of the present application. In some embodiments, the protective member 224 also includes a fourth protective member 2244. Along the radial direction of the electrode assembly 22, the second pole piece 222 includes a plurality of sixth arc segments 2223, and the projection of the second ending end 2221 is located at the sixth arc segment. Within the projection of arc segment 2223. At least one sixth arc segment 2223 is covered by the fourth protective member 2244.

By arranging the fourth protective member 2244 to cover the sixth arc segment 2223, while increasing the tensile strength of the sixth arc segment 2223, even if the sixth arc segment 2223 cracks, the new steps generated will be blocked by the fourth protective member. 2244 shielding will not have much impact on other arc segments located inside the sixth arc segment 2223. The coating method can better protect the sixth arc segment 2223 and improve the safety of the electrode assembly 22 .

Please refer to Figures 28 and 29. Figure 28 is a schematic structural diagram of the first protection member 2241 provided on one side of the first pole piece 221 according to some embodiments of the present application. FIG. 29 is a schematic structural diagram of the first protection member 2241 provided on both sides of the first pole piece 221 according to some embodiments of the present application. In the embodiment where the protective member 224 is provided on one side of the arc segment, along the first direction, the size of the protective member 224 is D1, and the size of the first pole piece 221 is D2, which satisfies D1/D2≥1/2. The first direction is parallel to the winding axis.

The first direction is the direction parallel to the winding axis. Please refer to Figure 28. The first direction is the A direction shown in the figure.

Along the first direction, the ratio of the size of the protective member 224 to the size of the first pole piece 221 is greater than or equal to 1/2. The protective member 224 includes the above-mentioned first protective member 2241, second protective member 2242, third protective member 2243 and fourth protective member 2244. “The ratio of the size of the protective member 224 to the size of the first pole piece 221 is greater than or equal to 1/2” refers to the first protective member 2241, the second protective member 2242, the third protective member 2243 and the fourth protective member 2244. The ratio of any size along the first direction to the size of the first pole piece 221 along the first direction is greater than or equal to 1/2.

Along the first direction, the ratio of the size of the protective member 224 to the size of the first pole piece 221 may be: D1/D2=0.5, 0.6, 0.7, 0.8, 0.9, 1, etc.

The size of the protective member 224 in the first direction is greater than or equal to half of the size of the first pole piece 221 in the first direction, so as to achieve a better protection effect on the first pole piece 221. If D1/D2<1/2, the protection effect of the protective member 224 on the first pole piece 221 is poor. Compared with the solution where D1/D2≥1/2, the risk of cracking of the first pole piece 221 is higher. big.

In some embodiments, along the first direction, the protective member 224 is located in the middle of the corresponding first pole piece 221 or the second pole piece 222 .

"The protective member 224 is located in the middle of the corresponding first pole piece 221 or the second pole piece 222" means that the first protective member 2241 is provided in the middle of the first pole piece 221, and the second protective member 2242 is provided in the second pole piece 222. The third protective member 2243 is provided in the middle of the first pole piece 221 , and the fourth protective member 2244 is provided in the middle of the second pole piece 222 .

The middle parts of the first pole piece 221 and the second pole piece 222 are relatively easy to crack. Therefore, if the length of the protective member 224 in the first direction is smaller than the length of the corresponding first pole piece 221 or the second pole piece 222 in the first direction, length, then priority is given to protecting the middle part of the corresponding first pole piece 221 or the second pole piece 222.

Please refer to FIG. 30 , which is a schematic structural diagram of the electrode assembly 22 provided by some embodiments of the present application (the first protective member 2241 and the third protective member 2243 are the same protective member 224 ). In some embodiments, along the winding direction, the first ending end 2211 extends beyond the second ending end 2221 by a distance L1, which satisfies: L1 ≤ 20 mm. The first protective member 2241 and the third protective member 2243 are the same component. Or the first protective member 2241 and the third protective member 2243 are partially overlapped.

L1 represents the distance beyond the second ending end 2221 of the first ending end 2211 in the winding direction. The value of L1 can be 20mm, 19mm, 18mm, 15mm, 13mm, 10mm, etc.

If the distance between the first ending end 2211 and the second ending end 2221 is less than or equal to 20 mm along the winding direction, then the distance between the first ending end 2211 and the second ending end 2221 is relatively close, and the first protective member 2241 and the second ending end 2221 can be separated. The third protective member 2243 is provided as the same component, and the first protective member 2241 and the second protective member 2242 may also be partially overlapped to protect the first pole piece 221 .

In some embodiments, the first protective member 2241 and the third protective member 2243 are partially overlapped. Along the winding direction, the length of the overlapping part is L2, which satisfies L2≥10mm.

L2 represents the length of the overlapping portion of the first protective member 2241 and the third protective member 2243 along the winding direction. The value of L2 can be L2=10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc.

The first protective member 2241 and the third protective member 2243 are partially overlapped. The overlapping portion will generate a new step. When the length of the overlapping portion L2 ≥ 10 mm, the shearing force generated by the new step on the first pole piece 221 can be effectively transferred. , to prevent the first pole piece 221 from cracking due to excessive local shearing force. If the length L2 of the overlapping portion is less than 10 mm, the new step generated by the overlap of the first protective member 2241 and the second protective member 2242 will produce a large shearing force on the first pole piece 221, causing local shearing of the first pole piece 221. Shear stress concentration phenomenon, compared with L2≥10mm, the first pole piece 221 has a greater risk of cracking.

Please refer to Figure 30. In some embodiments, along the winding direction, the size of the protective member 224 is L3, which satisfies: L3≥10mm.

L3 represents the size of the protective member 224 along the winding direction, and can also be understood as the length of the protective member 224 . The protective part 224 includes a first protective part 2241, a second protective part 2242, a third protective part 2243 and a fourth protective part 2244. Along the winding direction, the size of the protective member 224 means that the size of any one of the first protective member 2241 , the second protective member 2242 , the third protective member 2243 and the fourth protective member 2244 is greater than or equal to 10 mm.

Along the winding direction, the value L3 of the size of the protective member 224 may be: L3=10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc.

By making the size of the protective member 224 along the winding direction greater than or equal to 10 mm, the protective member 224 is ensured to have a sufficient length to prevent the protective member 224 from being misaligned with the first ending end 2211 or the second ending end 2221 during the expansion process of the electrode assembly 22 . Loss of protective effect.

Referring to FIG. 30 , in some embodiments, along the radial direction of the electrode assembly 22 , the thickness of the protective member 224 is T1 , and the thickness of the first pole piece 221 is T2 , satisfying: T1 < T2 .

Along the radial direction of the electrode assembly 22 , the thickness of the protective member 224 is smaller than the thickness of the first pole piece 221 . The protective member 224 includes a first protective member 2241, a second protective member 2242, a third protective member 2243 and a fourth protective member 2244. “Along the radial direction of the electrode assembly 22, the thickness of the protective member 224 is smaller than the thickness of the first pole piece 221.” That is, along the radial direction of the electrode assembly 22, the first protective member 2241, the second protective member 2242, the third protective member The thickness of any one of the member 2243 and the fourth protective member 2244 is smaller than the thickness of the first pole piece 221 .

The thickness of the protective member 224 is smaller than the thickness of the first pole piece 221. In this way, when the protective member 224 is disposed on the first pole piece 221, the steps protruding from the first pole piece 221 generated at the edge of the protective member 224 have a negative impact on the first pole. The shearing force of the piece 221 is small, and the first pole piece 221 is not easy to crack. If the thickness of the protective member 224 is greater than or equal to the thickness of the first pole piece 221, when the protective member 224 is disposed on the first pole piece 221, a pair of steps protruding from the first pole piece 221 will be generated at the edge of the protective member 224. The shearing force of the first pole piece 221 is relatively large, which may cause the first pole piece 221 to crack. In addition, the thickness of the protective member 224 is smaller than the thickness of the first pole piece 221. Compared with the thickness of the protective member 224 being greater than or equal to the thickness of the first pole piece 221, the thickness of the protective member 224 is thinner and takes up less space. Conducive to improving energy density.

Please refer to Figures 31, 32 and 33. Figure 31 is a schematic structural diagram of the electrode assembly 22 (the first protective member 2241 covers the first ending end 2211) provided by some embodiments of the present application. Figure 32 is a schematic structural diagram of the electrode assembly 22 (the second protective member 2242 covers the second ending end 2221) provided by some embodiments of the present application. Figure 33 is a schematic structural diagram of the electrode assembly 22 provided by some embodiments of the present application (the first protective member 2241 covers the first ending end 2211 and the second protective member 2242 covers the second ending end 2221). In some embodiments, the protective member 224 includes a first protective member 2241 and a second protective member 2242. The first protective member 2241 covers the first ending end 2211. And/or, the second pole piece 222 has a second ending end 2221, and the second protection member 2242 covers the second ending end 2221.

Referring to Figure 31, the first protective member 2241 covers the first ending end 2211. Referring to Figure 32, the second protective member 2242 covers the second ending end 2221. Please refer to FIG. 33 . While the first protective member 2241 covers the first ending end 2211 , the second protective member 2242 covers the second ending end 2221 .

By covering the first end end 2211 with the first protective member 2241, the shearing force exerted by the first end end 2211 on the first pole piece 221 can be effectively reduced, thereby reducing the risk of cracking of the first pole piece 221. In addition, the first protective member 2241 covers the first ending end 2211, which can block the burrs and debris on the first ending end 2211 and prevent the burrs and debris from penetrating the isolation film 223 and causing a short circuit, which is beneficial to improving the performance of the electrode assembly 22. safety. By covering the second end end 2221 with the second protective member 2242, the shearing force exerted by the second end end 2221 on the first pole piece 221 can be effectively reduced, thereby reducing the risk of cracking of the first pole piece 221. In addition, the second protective member 2242 covers the second ending end 2221, which can block the burrs and debris on the second ending end 2221 and prevent the burrs and debris from penetrating the isolation film 223 and causing a short circuit, which is beneficial to improving the performance of the electrode assembly 22. safety.

Please refer to FIG. 34 , which is a schematic structural diagram of the first protective member 2241 covering the first ending end 2211 provided by some embodiments of the present application. In some embodiments, the protective member 224 includes a first section 22411, a second section 22412, and a third section 22413 connected in sequence. Along the radial direction of the electrode assembly 22 , the first section 22411 and the third section 22413 are disposed oppositely on both sides of the corresponding first end end 2211 or the second end end 2221 .

The first protective member 2241 includes a first section 22411, a second section 22412 and a third section 22413. Along the radial direction of the electrode assembly 22 , the first section 22411 and the third section 22413 are relatively arranged on both sides of the corresponding first end end 2211 (the first protection member 2241 corresponds to the first end end 2211 ). The second protective member 2242 includes a first section 22411, a second section 22412, and a third section 22413. Along the radial direction of the electrode assembly 22, the first section 22411 and the third section 22413 are disposed oppositely on both sides of the corresponding second end end 2221 (the second protection member 2242 corresponds to the second end end 2221).

Referring to FIG. 34 , in some embodiments, along the radial direction of the electrode assembly 22 , the projection of the first section 22411 on the third section 22413 exceeds the third section 22413 .

"Along the radial direction of the electrode assembly 22, the projection of the first section 22411 on the third section 22413 exceeds the third section 22413" can also be understood to mean that along the winding direction, the length of the first section 22411 is longer than the length of the third section 22413. longer.

If the length of the first section 22411 is equal to the length of the third section 22413, a new step may be formed at the end of the first section 22411 away from the second section 22412, which acts on the adjacent first pole piece 221 or the second pole piece 22413. The pole piece 222 may easily cause the adjacent first pole piece 221 or the second pole piece 222 to crack. Therefore, along the winding direction, setting the length of the first section 22411 to be longer than the length of the third section 22413 is beneficial to reducing the height of the newly generated step and reducing the impact on the adjacent first pole piece 221 or the second pole. Risk of cracking of tablet 222.

In some embodiments, arc transitions are used at the corners of the protective member 224 .

"The corners of the protective member 224 adopt arc transitions" means that the corners of any one of the first protective member 2241, the second protective member 2242, the third protective member 2243 and the fourth protective member 2244 adopt arcs. transition.

Using arc transitions at the corners of any one of the first protective member 2241, the second protective member 2242, the third protective member 2243 and the fourth protective member 2244 can lower the first protective member 2241 and the second protective member 2242. , the amount of stress exerted by the corners of the third protective member 2243 and the fourth protective member 2244 on the first pole piece 221 or the second pole piece 222, and it is not easy to puncture the first pole piece 221 or the second pole piece 222.

In some embodiments, the tensile strength of the protector 224 is greater than the tensile strength of the pole piece.

"The tensile strength of the protective member 224 is greater than the tensile strength of the pole piece" refers to the tensile strength of "any one of the first protective member 2241, the second protective member 2242, the third protective member 2243 and the fourth protective member 2244" The strength is greater than the tensile strength of "either the first pole piece 221 or the second pole piece 222".

By making the tensile strength of the protective member 224 greater than the tensile strength of the pole piece, it is beneficial to enhance the tensile strength of the pole piece, reduce the deformation of the pole piece, and make the pole piece less likely to crack.

In some embodiments, the protective member 224 is an adhesive tape, and the adhesive tape is bonded to the corresponding first pole piece 221 or the second pole piece 222 .

The first protective member 2241 , the second protective member 2242 , the third protective member 2243 and the fourth protective member 2244 are all adhesive tapes. The first protective member 2241 and the third protective member 2243 are bonded to the first pole piece 221 . The second protective member 2242 and the fourth protective member 2244 are bonded to the second pole piece 222 .

The adhesive tape is bonded to the first pole piece 221 or the second pole piece 222, which has a better protective effect on the first pole piece 221 or the second pole piece 222, is simple and convenient, and has low cost. In addition, the thickness of the tape is smaller, which is beneficial to increasing energy density.

In other embodiments, the protective member 224 may be a glue layer, which is formed by applying glue on the first pole piece 221 or the second pole piece 222 and drying it. Of course, the protective member 224 can also be made of other insulating materials, such as plastic, rubber, etc.

The embodiment of the present application also provides a battery cell 20. The battery cell 20 includes the above-mentioned electrode assembly 22, casing 23 and end cover 21. The housing 23 has an accommodating space open at one end, and the accommodating space is used to accommodate the electrode assembly 22 . The end cap 21 is connected to the housing 23 and closes the opening.

The embodiment of the present application also provides a battery 100. The battery 100 includes a box 10 and the above-mentioned battery cells 20. The battery cells 20 are accommodated in the box 10.

An embodiment of the present application also provides an electrical device. The electrical device includes the above-mentioned battery 100, and the battery 100 is used to provide electric energy.

According to some embodiments of the present application, please refer to Figures 4 to 34.

The embodiment of the present application provides an electrode assembly 22. The electrode assembly 22 includes a first pole piece 221, a second pole piece 222, an isolation film 223 and a protective member 224. The first pole piece 221 and the second pole piece 222 have opposite polarities. The first pole piece 221, the isolation film 223 and the second pole piece 222 are wound along the winding direction to form the electrode assembly 22. The first pole piece 221 has a first ending end 2211, and the second pole piece 222 has a second ending end 2221. The first pole piece 221 is partially located outside the second ending end 2221, and the first ending end 2211 exceeds the second ending end 2221 along the winding direction. The protective part 224 includes a first protective part 2241. Along the radial direction of the electrode assembly 22 , the first pole piece 221 includes a plurality of arc segments, and the projection of the first end end 2211 is located within the projection of the arc segments. The outermost arc segment among the plurality of arc segments is the first arc segment 2212 . A first protective member 2241 is provided on the outer surface of the first arc segment 2212. Among the plurality of arc segments, the arc segment located inside the first arc segment 2212 is the second arc segment 2213 , and at least one second arc segment 2213 is provided with a first protection member 2241 .

The first arc segment 2212 is the arc segment closest to the first ending end 2211 among the multiple arc segments, and is also the arc segment most susceptible to the shearing force of the first ending end 2211. Therefore, the first protective member 2241 is provided on the outer surface of the first arc segment 2212 to protect the first arc segment 2212, reduce the risk of cracking of the first arc segment 2212, and improve the safety of the electrode assembly 22. By arranging the first protection member 2241 on at least one second arc segment 2213, on the one hand, the tensile strength of the second arc segment 2213 can be increased, making the second arc segment 2213 less likely to be broken during expansion (due to production reasons). Due to the influence of fluctuations during the process, the mechanical properties of the second arc segment 2213 at different positions are different, and the second arc segment 2213 may be broken before the first arc segment 2212). On the other hand, if the first arc segment 2212 cracks, a new step surface will be generated at the cracking position, and the new step surface will act on the second arc segment 2213, which will cause the second arc segment 2213 to crack. The first protective member 2241 provided on the arc segment 2213 can protect the second arc segment 2213, reduce the stress of the newly generated step on the second arc segment 2213, and reduce the risk of cracking in the second arc segment 2213.

Along the radial direction of the electrode assembly 22, a first protective member 2241 is provided on the inner surface of the first arc segment 2212. By also providing the first protective member 2241 on the inner surface of the first arc segment 2212, on the one hand, the tensile strength of the first arc segment 2212 can be increased, making the first arc segment 2212 less likely to be broken when expanding. On the other hand, if the first arc section 2212 cracks, the newly generated step surface at the cracked position will be blocked by the first protection member 2241 provided inside the first arc section 2212, thereby preventing the newly generated step surface from being located on the first The arc segment inside the arc segment 2212 applies shearing force to reduce the risk of cracking in the arc segment located inside the first arc segment 2212 .

Protector 224 also includes a second protector 2242. Along the radial direction of the electrode assembly 22 , the second pole piece 222 includes a plurality of third arc segments 2222 , and the projection of the first end end 2211 is located within the projection of the third arc segments 2222 . At least one third arc segment 2222 is provided with a second protection member 2242. By disposing the second protection member 2242 on at least one third arc segment 2222, on the one hand, the tensile strength of the third arc segment 2222 can be increased, making the third arc segment 2222 less likely to be broken during expansion (due to production reasons). Due to the influence of fluctuations during the process, the mechanical properties of the third arc segment 2222 located at different positions are different, and the third arc segment 2222 may be broken). On the other hand, if the third arc segment 2222 cracks, a new step surface will be generated at the cracking position, and the new step surface acting on the second arc segment 2213 will cause the second arc segment 2213 to crack. The second protective member 2242 provided on the arc segment 2222 can protect the third arc segment 2222 and reduce the risk of cracking in the third arc segment 2222. In addition, when the second arc segment 2213 or the first arc segment 2212 cracks, the second protection member 2242 can also reduce the shear force of the newly generated step surface on the third arc segment 2222, so as to reduce the third arc segment 2222. There is a risk of cracking in arc segment 2222.

Along the radial direction of the electrode assembly 22, the first pole piece 221 includes a plurality of arc segments. The projection of the first end 2211 is located in the arc segment. The outermost arc segment among the plurality of arc segments is the first arc segment. Arc 2212. The first protective member 2241 covers the first arc segment 2212. By arranging the first protective member 2241 to cover the first arc segment 2212, while increasing the tensile strength of the first arc segment 2212, even if the first arc segment 2212 cracks, the new steps generated will be blocked by the first protective member. 2241 shielding will not have much impact on other arc segments located inside the first arc segment 2212. The coating method can better protect the first arc segment 2212 and improve the safety of the electrode assembly 22 .

The protective member 224 includes a second protective member 2242. Along the radial direction of the electrode assembly 22, the second pole piece 222 includes a plurality of third arc segments 2222. The projection of the first end end 2211 is located within the projection of the third arc segment 2222. . At least one third arc segment 2222 is covered by the second protective member 2242. By arranging the second protective member 2242 to cover the third arc segment 2222, while increasing the tensile strength of the third arc segment 2222, even if the third arc segment 2222 cracks, the new steps generated will be blocked by the second protective member. 2242 shielding will not have much impact on other arc segments located inside the third arc segment 2222. The coating method can better protect the third arc segment 2222 and improve the safety of the electrode assembly 22 .

The protective member 224 includes a third protective member 2243. Along the radial direction of the electrode assembly 22, the first pole piece 221 includes a fourth arc segment 2214, and the projection of the second end end 2221 is located within the projection of the fourth arc segment 2214. The four arc segments 2214 are adjacent to the second ending end 2221. A third protective member 2243 is provided on the surface of the fourth arc segment 2214 facing the second ending end 2221 . The fourth arc segment 2214 is the position on the first pole piece 221 that is most susceptible to the shear force of the second ending end 2221 and causes cracking. By setting a third arc segment on the surface of the fourth arc segment 2214 facing the second ending end 2221 The protective member 2243 is used to protect the fourth arc segment 2214 and reduce the risk of cracking of the first pole piece 221 due to the shear force of the second ending end 2221.

Along the radial direction of the electrode assembly 22, the first pole piece 221 includes a fifth arc segment 2215. The projection of the second end end 2221 is located within the projection of the fifth arc segment 2215. The fifth arc segment 2215 is located in the fourth arc segment. The inner side of segment 2214. At least one fifth arc segment 2215 is provided with a third protection member 2243. By arranging the third protective member 2243 on at least one fifth arc segment 2215, on the one hand, the tensile strength of the fifth arc segment 2215 can be increased, making the fifth arc segment 2215 less likely to be broken during expansion (due to production reasons). Due to the influence of fluctuations during the process, the fifth arc segment 2215 located at different positions has different mechanical properties, and the fifth arc segment 2215 may be broken before the fourth arc segment 2214). On the other hand, if the fourth arc segment 2214 cracks, a new step surface will be generated at the cracking position, and the new step surface acting on the fifth arc segment 2215 will cause the fifth arc segment 2215 to crack. The third protective member 2243 provided on the arc segment 2215 can protect the fifth arc segment 2215, reduce the stress of the newly generated step on the fifth arc segment 2215, and reduce the risk of cracking in the fifth arc segment 2215.

The protective member 224 also includes a fourth protective member 2244. Along the radial direction of the electrode assembly 22, the second pole piece 222 includes a plurality of sixth arc segments 2223, and the projection of the second end end 2221 is located at the projection of the sixth arc segment 2223. Inside, at least one sixth arc segment 2223 is provided with a fourth protection member 2244. By disposing the fourth protective member 2244 on at least one sixth arc segment 2223, on the one hand, the tensile strength of the sixth arc segment 2223 can be increased, making the sixth arc segment 2223 less likely to be broken during expansion (due to production reasons). Due to the influence of fluctuations during the process, the mechanical properties of the sixth arc segment 2223 located at different positions are different, and the sixth arc segment 2223 may be broken). On the other hand, if the sixth arc segment 2223 cracks, a new step surface will be generated at the cracking position, and the new step surface acting on the fifth arc segment 2215 will cause the fifth arc segment 2215 to crack. The fourth protective member 2244 provided on the arc segment 2223 can protect the sixth arc segment 2223 and reduce the risk of cracking in the sixth arc segment 2223. In addition, when the fourth arc segment 2214 or the fifth arc segment 2215 cracks, the fourth protective member 2244 can also reduce the shear force of the sixth arc segment 2223 from the newly generated step surface, so as to reduce the shear force of the sixth arc segment 2223. There is a risk of cracking in arc segment 2223.

The protective member 224 includes a first protective member 2241 and a second protective member 2242. The first protective member 2241 covers the first ending end 2211. And/or, the second pole piece 222 has a second ending end 2221, and the second protection member 2242 covers the second ending end 2221. By covering the first end end 2211 with the first protective member 2241, the shearing force exerted by the first end end 2211 on the first pole piece 221 can be effectively reduced, thereby reducing the risk of cracking of the first pole piece 221. In addition, the first protective member 2241 covers the first ending end 2211, which can block the burrs and debris on the first ending end 2211 and prevent the burrs and debris from penetrating the isolation film 223 and causing a short circuit, which is beneficial to improving the performance of the electrode assembly 22. safety. By covering the second end end 2221 with the second protective member 2242, the shearing force exerted by the second end end 2221 on the first pole piece 221 can be effectively reduced, thereby reducing the risk of cracking of the first pole piece 221. In addition, the second protective member 2242 covers the second ending end 2221, which can block the burrs and debris on the second ending end 2221 and prevent the burrs and debris from penetrating the isolation film 223 and causing a short circuit, which is beneficial to improving the performance of the electrode assembly 22. safety.

The above descriptions are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included in the protection scope of this application.

Claims

An electrode assembly, including:

The first pole piece, the second pole piece and the isolation film. The first pole piece and the second pole piece have opposite polarities. The first pole piece, the isolation film and the second pole piece are along the The electrode assembly is formed by winding in the winding direction, and the first pole piece has a first ending end;

A protective piece is provided on the first pole piece and/or the second pole piece, and is configured to prevent the first end end from contacting the first pole piece and the second pole piece. The adjacent parts of the first finishing end are in contact.
The electrode assembly according to claim 1, wherein the protective member includes a first protective member, the second pole piece has a second ending end, the first pole piece is partially located outside the second ending end, and The first ending end exceeds the second ending end along the winding direction, and the first protective member is provided on the first pole piece to prevent the first ending end from contacting all adjacent ends. The first pole piece contacts.
The electrode assembly according to claim 2, wherein along the radial direction of the electrode assembly, the first pole piece includes a plurality of arc segments, and the projection of the first end end is located within the projection of the arc segments, The outermost arc segment among the plurality of arc segments is the first arc segment, and the first protective member is provided on the outer surface of the first arc segment.
The electrode assembly according to claim 3, wherein the first protective member is provided on the inner surface of the first arc segment along the radial direction of the electrode assembly.
The electrode assembly according to claim 3 or 4, wherein the arc segment located inside the first arc segment among the plurality of arc segments is a second arc segment, and at least one of the second arc segment The first protective piece is provided.
The electrode assembly according to any one of claims 2 to 5, wherein the protective member further includes a second protective member, and along the radial direction of the electrode assembly, the second pole piece includes a plurality of third arc segments. , the projection of the first ending end is located within the projection of the third arc segment, and at least one of the third arc segments is provided with the second protection member.
The electrode assembly according to claim 6, wherein the second protection member is provided on both sides of at least one third arc segment along the radial direction of the electrode assembly.
The electrode assembly according to claim 2, wherein along the radial direction of the electrode assembly, the first pole piece includes a plurality of arc segments, the projection of the first end end is located on the arc segment, and the plurality of arc segments The outermost arc segment among the arc segments is the first arc segment, and the first protective member covers the first arc segment.
The electrode assembly according to claim 8, wherein the protective member includes a second protective member, and along the radial direction of the electrode assembly, the second pole piece includes a plurality of third arc segments, and the first ending The projection of the end is located within the projection of the third arc segment, and at least one of the third arc segments is covered by the second protective member.
The electrode assembly according to any one of claims 2 to 9, wherein the protective member further includes a third protective member, the third protective member is used to prevent the second terminal end from contacting the first pole piece. .
The electrode assembly according to claim 10, wherein the portion of the first pole piece located outside the second ending end and/or the portion of the first pole piece located inside the second ending end is provided with the said The third protective piece.
The electrode assembly according to claim 10 or 11, wherein, along the radial direction of the electrode assembly, the first pole piece includes a fourth arc segment, and the projection of the second end end is located in the fourth arc segment. In the projection, the fourth arc segment is adjacent to the second ending end, and the third protective member is provided on the surface of the fourth arc segment facing the second ending end.
The electrode assembly according to claim 12, wherein along the radial direction of the electrode assembly, the first pole piece includes a fifth arc segment, and the projection of the second end end is located at the projection of the fifth arc segment. Inside, the fifth arc segment is located inside the fourth arc segment, and at least one of the fifth arc segments is provided with the third protection member.
The electrode assembly according to any one of claims 10 to 13, wherein the protective member further includes a fourth protective member, and along the radial direction of the electrode assembly, the second pole piece includes a plurality of sixth arc segments. , the projection of the second ending end is located within the projection of the sixth arc segment, and at least one of the sixth arc segments is provided with the fourth protective member.
The electrode assembly according to claim 10, wherein along the radial direction of the electrode assembly, the first pole piece includes a fourth arc segment, and the projection of the second end end is located at the projection of the fourth arc segment. Inside, the fourth arc segment is adjacent to the second ending end, and the third protective member covers the fourth arc segment.
The electrode assembly according to claim 15, wherein the protective member further includes a fourth protective member, and along the radial direction of the electrode assembly, the second pole piece includes a plurality of sixth arc segments, and the second The projection of the ending end is located within the projection of the sixth arc segment, and at least one of the sixth arc segments is covered by the fourth protective member.
The electrode assembly according to any one of claims 3-7 and 12-14, wherein along the first direction, the size of the protective member is D1, the size of the first pole piece is D2, and satisfies D1/D2≥ 1/2;

The first direction is parallel to the winding axis.
The electrode assembly according to claim 17, wherein the protective member is located in the middle of the corresponding first pole piece or second pole piece along the first direction.
The electrode assembly according to any one of claims 10 to 16, wherein along the winding direction, the distance beyond the first ending end from the second ending end is L1, which satisfies: L1≤20mm;

The first protective piece and the third protective piece are the same component; or

The first protective member and the third protective member are partially overlapped.
The electrode assembly according to claim 19, wherein the first protective member and the third protective member are partially overlapped, and along the winding direction, the length of the overlapping portion is L2, satisfying L2 ≥ 10 mm.
The electrode assembly according to any one of claims 1 to 20, wherein along the radial direction of the electrode assembly, the thickness of the protective member is T1, and the thickness of the first pole piece is T2, satisfying: T1<T2 .
The electrode assembly according to any one of claims 1 to 21, wherein the protective member includes a first protective member and a second protective member, the first protective member covers the first ending end; and/or,

The second pole piece has a second ending end, and the second protective member covers the second ending end.
The electrode assembly according to any one of claims 1 to 22, wherein the protective member is an adhesive tape, and the adhesive tape is adhered to the corresponding first pole piece or the second pole piece.
A battery cell, including:

The electrode assembly according to any one of claims 1-23;

A housing having a receiving space open at one end, the receiving space being used to accommodate the electrode assembly;

An end cap is connected to the housing and closes the opening.
A battery, including:

box;

The battery cell according to claim 24, which is accommodated in the box.
An electrical device, comprising the battery according to claim 25, the battery being used to provide electrical energy.