Electrode assembly, battery cell, battery and electric device

Abstract

The utility model provides an electrode assembly, a battery monomer, a battery and a power utilization device. The electrode assembly comprises a first pole piece and a second pole piece which are opposite in polarity. The first pole piece comprises a first pole piece main body, the first pole piece main body comprises a first current collecting main body and a first active material layer, the first current collecting main body comprises two first surfaces which are oppositely arranged along the thickness direction of the first current collecting main body and a first end surface which is connected with the two first surfaces, and the first active material layer is arranged on the first surfaces. The electrode assembly further comprises an insulating part connected to the first pole piece body, at least part of the insulating part is arranged on the outer side of the first end face in the first direction, and the first direction is perpendicular to the thickness direction. The insulating part can separate the burrs on the first end face from the second pole piece, so that the risk of conduction between the burrs and the second pole piece is reduced, the possibility of thermal runaway caused by short circuit is reduced, and the reliability of the single battery is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and more specifically, to an electrode assembly, a battery cell, a battery, and an electrical device. Background Art

[0002] Battery monomers are widely used in electronic devices, such as mobile phones, laptop computers, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc.

[0003] In the development of battery technology, how to improve the reliability of battery cells is a research direction in battery technology. Summary of the invention

[0004] The present application provides an electrode assembly, a battery cell, a battery, and an electrical device, which can improve reliability.

[0005] In a first aspect, an embodiment of the present application provides an electrode assembly, comprising a first pole piece and a second pole piece with opposite polarities. The first pole piece comprises a first pole piece body, the first pole piece body comprises a first current collecting body and a first active material layer, the first current collecting body comprises two first surfaces arranged opposite to each other along its thickness direction and a first end face connecting the two first surfaces, and the first active material layer is arranged on the first surface. The electrode assembly also comprises an insulating member connected to the first pole piece body, at least part of the insulating member is arranged on the outside of the first end face along a first direction, and the first direction is perpendicular to the thickness direction.

[0006] The insulating member can separate the burr on the first end surface from the second pole piece, thereby reducing the risk of the burr and the second pole piece being connected, reducing the possibility of thermal runaway caused by short circuit, and improving the reliability of the battery cell.

[0007] In one or more optional embodiments above, the insulating member includes two first insulating portions and a second insulating portion. The two first insulating portions are respectively located on both sides of the first pole piece body along the thickness direction and connected to the first pole piece body. The second insulating portion connects the two first insulating portions and is arranged on the outer side of the first end surface along the first direction.

[0008] By providing two first insulating parts, the connection area between the insulating member and the first pole piece body can be increased, and the risk of the insulating member falling off can be reduced. The second insulating part can separate the burrs on the first end surface from the second pole piece, thereby reducing the risk of short circuit.

[0009] In one or more of the above optional embodiments, the second insulating portion covers at least a portion of the first end surface to cover the burrs on the first end surface, thereby further reducing the risk of short circuit.

[0010] In one or more optional embodiments above, the first pole piece further includes a first pole ear connected to the first current collector, the first end surface includes a pole ear lead-out region and a non-pole ear lead-out region, the first pole ear is only led out from the pole ear lead-out region, and protrudes from the second insulating portion along the first direction away from the first current collector. The first pole ear protrudes from the second insulating portion to facilitate connection with other conductive structures, reducing the risk of interference between the second insulating portion and the conductive structure.

[0011] In one or more optional embodiments above, the second insulating portion covers at least a portion of the non-tab lead-out region. The second insulating portion can separate the burrs on the non-tab lead-out region from the second pole piece, thereby reducing the risk of short circuit.

[0012] In one or more optional embodiments above, the second insulating portion is only provided on the outer side of the non-tab lead-out region along the first direction to reduce the usage of the insulating member.

[0013] In one or more optional embodiments above, the second insulating portion includes a first extension portion and a second extension portion, the first extension portion is arranged on the outside of the non-pole tab lead-out area along the first direction, and the second extension portion is arranged on the outside of the pole tab lead-out area along the first direction and covers at least part of the pole tab along the thickness direction.

[0014] The first extension can separate the burrs on the non-ear lead-out area from the second pole piece, thereby reducing the risk of short circuit. The second extension can support the root of the first pole ear close to the ear lead-out area, reducing the risk of the first pole ear being inserted upside down between the first pole piece and the second pole piece when being bent, thereby reducing the risk of short circuit and improving reliability.

[0015] In one or more optional embodiments above, the first extension portion covers the non-tab lead-out area along the first direction to shield burrs on the non-tab lead-out area.

[0016] In one or more optional embodiments above, the dimension of the first extension portion along the first direction is equal to the dimension of the second extension portion along the first direction. The second insulating portion is arranged with equal width, which is easy to shape.

[0017] In one or more optional embodiments above, the first extension portion is provided with a first part and a second part, the second part is connected to the second extension portion, the size of the second part along the first direction is equal to the size of the second extension portion along the first direction, the first part is configured to be formed by providing a recess on the second insulating portion, and the size of the first part along the first direction is smaller than the size of the second extension portion along the first direction. By providing the recess, the size of the first part along the first direction can be reduced, thereby saving the amount of insulating parts used and improving the energy density of the battery cell.

[0018] In one or more optional embodiments above, in the first direction, the size of the root area of ​​the first pole tab covered by the second extension portion is greater than or equal to 0.2 times the size of the first pole tab. The second extension portion can provide effective support for the first pole tab, reduce the risk of the first pole tab being inserted upside down between the first pole piece and the second pole piece, and improve reliability.

[0019] In one or more optional embodiments above, in the first direction, the size of the root area of ​​the first pole lug covered by the second extension portion is less than or equal to 0.6 times the size of the first pole lug, so as to reduce the volume and weight of the insulating member and improve the energy density.

[0020] In one or more of the above optional embodiments, the first insulating portion is connected to the first active material layer, which can increase the connection area between the insulating member and the first pole piece body and reduce the risk of the insulating member falling off.

[0021] In one or more optional embodiments above, at least a portion of the first insulating portion overlaps with the first active material layer in the thickness direction and is connected to the first active material layer to further increase the connection area between the first insulating portion and the first pole piece body.

[0022] In one or more optional embodiments above, the first active material layer includes a main body region arranged along the first direction and a thinning region connected to the main body region, the thinning region is located on one side of the main body region close to the first end face along the first direction, and the thickness of at least part of the thinning region is less than the thickness of the main body region. The first insulating portion covers at least part of the thinning region along the thickness direction.

[0023] By providing the thinning area, the pressure on the edge of the first active material layer can be reduced during the rolling of the first pole piece, reducing the risk of cracking of the first current collector. The first insulating part can be arranged using the space on one side of the thinning area along the thickness direction to improve space utilization.

[0024] In one or more of the above optional embodiments, along the direction from the first current collecting body to the first active material layer, the first insulating portion does not extend beyond the surface of the main region away from the first current collecting body, so as to reduce the extra space occupied by the first insulating portion in the thickness direction, improve space utilization, and reduce the risk of the first insulating portion squeezing the second pole piece.

[0025] In one or more optional embodiments above, in the first direction, the first insulating portion and the main body region are spaced apart so that the main body region and the first insulating portion do not overlap in the thickness direction, thereby improving space utilization.

[0026] In one or more optional embodiments above, the first insulating portion covers part of the main body area. The first insulating portion is connected to the main body area and the thinning area at the same time, which can increase the connection area between the insulating member and the first pole piece body and reduce the risk of the insulating member falling off.

[0027] In one or more optional embodiments above, the thickness t1 of the end of the thinned area away from the main area is less than or equal to 0.5 times the thickness t2 of the main area. The end of the thinned area away from the main area has a smaller thickness, which can reduce the area covered by the second insulating part, reduce the force at the connection between the first insulating part and the second insulating part, and reduce the risk of cracking and falling off of the insulating part.

[0028] In one or more optional embodiments above, the first surface includes a coated area and an uncoated area arranged along a first direction, one end of the uncoated area is connected to the first end surface, and the other end is connected to the coated area, the coated area is coated with the first active material layer, and the uncoated area is not coated with the first active material layer. The first insulating portion is connected to the uncoated area.

[0029] By providing the uncoated area, the connection area between the first current collector and the insulating member can be increased, the risk of the insulating member falling off can be reduced, and the reliability can be improved. The first end surface and the first active material layer are arranged at intervals along the first direction, so that the risk of cutting the first active material layer during the cutting process of the first pole piece can be reduced, and the waste of active material can be reduced.

[0030] In one or more of the above optional embodiments, the first insulating portion completely covers the uncoated area to reduce the possibility of conduction between the uncoated area and the second pole piece, reduce the risk of short circuit, and improve reliability.

[0031] In one or more of the above optional embodiments, in the first direction, the size of the area where the insulating member covers the uncoated area is greater than or equal to 1 mm, so as to increase the connection strength between the insulating member and the uncoated area and reduce the risk of the insulating member falling off the first pole piece.

[0032] In one or more optional embodiments above, the first pole piece further includes a first pole lug, which extends outward from the first end surface along the first direction and passes through the second insulating portion.

[0033] In one or more optional embodiments above, the insulating member includes two independently formed insulating layers, the insulating layer includes an insulating body and a connecting portion connected to the insulating body; in the thickness direction, the insulating body overlaps with the first pole piece body, and the connecting portion does not overlap with the first pole piece body. The insulating bodies of the two insulating layers respectively form two first insulating portions; the connecting portions of the two insulating layers are stacked and connected to form a second insulating portion.

[0034] The two insulating layers can be attached to the first pole piece body from both sides to form an insulating member, which helps to simplify the assembly process of the first pole piece and the insulating member.

[0035] In one or more optional embodiments above, the thickness of the insulating layer is 7 μm-30 μm. Limiting the thickness of the insulating layer to be greater than or equal to 7 μm can reduce the risk of the insulating layer being pierced by burrs and improve reliability. Limiting the thickness of the insulating layer to be less than or equal to 30 μm can reduce the space and weight occupied by the insulating layer and reduce the loss of energy density of the battery cell.

[0036] In one or more of the above optional embodiments, the insulation value of the difference between the thickness of the insulating layer and the thickness of the first current collecting body is not greater than 10 μm. On the premise that the overcurrent of the first current collecting body meets the requirements, the risk of the insulating layer being pierced by burrs is reduced, and the weight and space occupied by the insulating layer are reduced, thereby improving the energy density.

[0037] In one or more of the above optional embodiments, an insulation value of a difference between a thickness of the insulating layer and a thickness of the first current collecting body is not greater than 5 μm.

[0038] In one or more optional embodiments above, the first end surface includes a pole lug lead-out area and a non-pole lug lead-out area, and the first pole lug extends only from the pole lug lead-out area and protrudes from the second insulating portion in a direction away from the first current collector. The two connecting portions are directly connected to the non-overlapping portion of the first pole lug and form a first extension portion, and the first extension portion covers the non-pole lug lead-out area along the first direction. The portion where the two connecting portions overlap with the first pole lug forms a second extension portion, and covers at least part of the first pole lug in the thickness direction. The first extension portion can cover the non-pole lug lead-out area, thereby shielding the burrs on the non-pole lug lead-out area and reducing the risk of short circuit.

[0039] In one or more of the above optional embodiments, a dimension of the first extending portion along the first direction is equal to a dimension of the second extending portion along the first direction.

[0040] In one or more of the above optional embodiments, the insulating member is an integrally formed structure, which can enhance the stability of the connection between the insulating member and the first pole piece body.

[0041] In one or more optional embodiments above, the first current collector further includes two second end faces, the two second end faces are respectively arranged at the two ends of the first end face, and each second end face connects the two first surfaces. The insulating member further includes a third insulating portion, which is connected to the first insulating portion and the second insulating portion and covers a portion of the second end face. The third insulating portion can cover the burrs on the second end face, thereby reducing the risk of short circuit and improving reliability. By providing the third insulating portion, the risk of exposing the first end face due to assembly error can also be reduced.

[0042] In one or more optional embodiments above, the first current collector includes two first end faces arranged opposite to each other along a first direction, and the first direction is perpendicular to the thickness direction of the first pole piece body. The electrode assembly includes two insulating members, and the two insulating members are respectively arranged on the outsides of the two first end faces. The two insulating members can separate the burrs on the two first end faces from the second pole piece, thereby further reducing the risk of short circuit.

[0043] In one or more optional embodiments above, the electrode assembly further comprises a separator, which is used to separate the first electrode sheet from the second electrode sheet. In the first direction, one end of the second insulating portion away from the first insulating portion exceeds the separator.

[0044] The second insulating portion protrudes from the isolation piece. When the first pole ear is bent, the second insulating portion can limit the first pole ear, reduce the risk of the first pole ear squeezing the isolation piece, reduce the wrinkles of the isolation piece, reduce the risk of the isolation piece shrinking inwards, and improve reliability.

[0045] In one or more of the above optional embodiments, the electrode assembly further includes a separator, which is used to separate the first pole piece from the second pole piece. In the first direction, the end of the second insulating portion away from the first insulating portion does not exceed the separator, so as to reduce the amount of the second insulating portion, reduce the weight and space occupied by the second insulating portion, and improve the energy density.

[0046] In one or more optional embodiments above, the second pole piece includes a second pole piece body, and the second pole piece body is stacked with the first pole piece body. The second pole piece body includes a second current collecting body and a second active material layer, and the second current collecting body includes two second surfaces arranged opposite to each other and a third end face connecting the two second surfaces, and the second active material layer is arranged on the second surface. The first end face is located at one end of the first current collecting body along the first direction, and the third end face is located at one end of the second current collecting body along the first direction. In the thickness direction, the insulating member separates the third end face from the first pole piece.

[0047] The insulating member can also separate the burrs on the third end surface from the first pole piece, thereby reducing the risk of the burrs on the third end surface being connected to the first pole piece, reducing the possibility of thermal runaway caused by short circuit, and improving the reliability of the battery cell.

[0048] In one or more optional embodiments above, the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece. In the first direction, both ends of the second active material layer extend beyond the first pole piece body. The insulating member blocks at least a portion of the first end face, and even if the second active material layer overlaps with the first end face in the stacking direction, it is not easy to contact the burrs on the first end face. The second active material layer can provide more embedding sites for the active ions released from the first active material layer, thereby reducing the risk of active ion precipitation, improving the cycle performance of the battery cell, and improving reliability.

[0049] In one or more optional embodiments above, the melting point of the insulating member is 95° C.-150° C. During the charge and discharge process of the battery cell, the first current collector generates heat. The insulating member has a higher melting point, which can reduce the risk of the insulating member being softened and falling off by heat, thereby improving reliability.

[0050] In one or more optional embodiments above, the insulating member includes a colloid, and the colloid includes at least one of ethylene and its copolymers, polyolefins, polyesters, polyurethanes, polyamides, styrene and its block copolymers. The colloid has a high bonding strength and is not easy to fall off from the first pole piece body.

[0051] In one or more optional embodiments above, the insulating member includes a substrate layer and an adhesive layer, and the substrate layer is connected to the first pole piece body through the adhesive layer. The substrate layer can improve the strength of the insulating member and reduce the deformation of the insulating member during the attachment process. The adhesive layer can adhere the substrate layer to the first pole piece body, reducing the risk of the substrate layer falling off from the first pole piece body.

[0052] In one or more optional embodiments above, the substrate layer includes at least one of polyethylene terephthalate, polypropylene, polyethylene and block copolymers thereof, and the adhesive layer includes at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene or butyl rubber.

[0053] In one or more optional embodiments above, the elastic modulus of the insulating member is 500Mpa-3000Mpa, and optionally, the elastic modulus of the insulating member is 770Mpa-1320Mpa. The insulating member has a high elastic modulus, which can provide support for the first pole lug, reduce the risk of the root of the first pole lug being inserted between the first pole piece and the second pole piece, and improve reliability.

[0054] In one or more of the above optional embodiments, the tensile strength of the insulating member is 949 kgf / cm 2 -1363kgf / cm 2 The insulating member has a high tensile strength and is not easily deformed when subjected to a tensile force from the first pole piece. Accordingly, the insulating member can effectively limit the deformation of the first pole piece, reduce the risk of the root of the first pole piece being inserted inverted between the first pole piece and the second pole piece, and improve reliability.

[0055] In one or more optional embodiments above, the insulating member is connected to the first active material layer. The peel strength between the insulating member and the first active material layer is higher than the peel strength between the first active material layer and the first surface. The peel strength between the insulating member and the first active material layer is high, thereby reducing the risk of the insulating member falling off and improving reliability.

[0056] In one or more optional embodiments above, the electrode assembly further includes a separator, which is used to separate the first pole piece from the second pole piece. The first pole piece, the separator, and the second pole piece are wound, and in the winding direction of the first pole piece, both ends of the insulating member do not exceed the separator. The separator can restrain the insulating member, keep the insulating member in contact with the main body of the first pole piece, and reduce the risk of the insulating member falling off the main body of the first pole piece.

[0057] In one or more optional embodiments above, the electrode assembly further includes a separator, which is used to separate the first pole piece from the second pole piece. The first pole piece body is in the shape of a flat plate, and in the second direction, both ends of the insulating member do not exceed the separator, and the second direction is perpendicular to the first direction and the thickness direction. The separator can restrain the insulating member, keep the insulating member in contact with the first pole piece body, and reduce the risk of the insulating member falling off the first pole piece body.

[0058] In a second aspect, an embodiment of the present application provides a battery cell, comprising a housing and an electrode assembly provided according to any one of the embodiments of the first aspect, wherein the electrode assembly is accommodated in the housing.

[0059] In a third aspect, an embodiment of the present application provides a battery, comprising a plurality of battery cells provided according to any implementation of the second aspect.

[0060] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising a battery provided according to any implementation of the third aspect, and the battery is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0062] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0063] Figure 2 An exploded schematic diagram of a battery provided in some embodiments of the present application;

[0064] Figure 3 An exploded schematic diagram of a battery cell provided in some embodiments of the present application;

[0065] Figure 4 A schematic top view of an electrode assembly provided in some embodiments of the present application;

[0066] Figure 5 for Figure 4A schematic partial cross-sectional view taken along the AA direction;

[0067] Figure 6 A schematic diagram of a first pole piece of an electrode assembly provided in some embodiments of the present application in a flattened state;

[0068] Figure 7 for Figure 6 A schematic cross-sectional view taken along the EE direction;

[0069] Figure 8 for Figure 6 Schematic diagram from another angle;

[0070] Fig. 9 for Figure 6 A schematic diagram of the first pole piece after being connected to the insulating member is shown;

[0071] Fig.10 A schematic diagram of an insulating member of an electrode assembly provided in some embodiments of the present application;

[0072] Fig.11 for Fig. 9 A schematic cross-sectional view taken along the BB direction;

[0073] Fig.12 for Fig. 9 Cross-sectional view along CC direction;

[0074] Fig.13 for Fig. 9 A schematic diagram of the first pole piece and the insulating member shown at another angle;

[0075] Fig.14 A schematic diagram of an insulating layer of an electrode assembly provided in some embodiments of the present application in a flattened state;

[0076] Fig.15 A schematic diagram of a first electrode sheet of an electrode assembly in an unfolded state provided in some other embodiments of the present application;

[0077] Fig.16 for Fig.15 A schematic diagram of the first pole piece after being connected to the insulating member is shown;

[0078] Fig.17 for Fig.16 Schematic cross-sectional view along the DD direction;

[0079] Fig.18 A schematic diagram of an insulating member provided in some embodiments of the present application before being assembled to a first pole piece;

[0080] Fig.19 A schematic diagram of a first pole piece and an insulating member of an electrode assembly in an unfolded state provided by some other embodiments of the present application;

[0081] Fig. 20 for Fig.19 An enlarged schematic diagram at the circle frame;

[0082] Fig.21 A schematic diagram of the structure of an insulating member of an electrode assembly provided in some embodiments of the present application;

[0083] Fig. 22 A partial cross-sectional schematic diagram of an electrode assembly provided in some other embodiments of the present application;

[0084] Fig.23 A schematic top view of an electrode assembly provided in some other embodiments of the present application;

[0085] Fig.24 for Fig.23 Schematic diagram of the cross section along the FF direction;

[0086] Fig.25 A schematic cross-sectional view of a first pole piece and an insulating member of an electrode assembly provided in some other embodiments of the present application;

[0087] Fig.26 Schematic diagram of electrode assemblies provided in some other embodiments of the present application;

[0088] Fig. 27 Schematic diagram of the first pole piece and insulating member of the electrode assembly in the unfolded state provided in some other embodiments of the present application.

[0089] The reference numerals are as follows:

[0090] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Box; 5a. First box part; 5b. Second box part; 5c. Accommodation space; 6. Battery cell;

[0091] 10. electrode assembly; 20. housing; 21. shell; 22. end cap; 30. electrode terminal;

[0092] 11. first pole piece; 111. first pole piece body; 112. first current collecting body; 1121. first surface; 1121a. coated area; 1121b. uncoated area; 1122. first end surface; 1122a. pole ear lead-out area; 1122b. non-pole ear lead-out area; 1123. second end surface; 113. first active material layer; 1131. main body area; 1132. thinning area; 114. first pole ear;

[0093] 12. second pole piece; 121. second pole piece body; 122. second current collecting body; 1221. second surface; 1222. third end face; 123. second active material layer; 124. second pole ear;

[0094] 13. Isolation parts;

[0095] 14. Insulating member; 141. First insulating portion; 142. Second insulating portion; 1421. First extension portion; 1421a. First portion; 1421b. Second portion; 1422. Second extension portion; 142a. Channel; 143. Third insulating portion; 144. Insulating layer; 144a. Insulating body; 144b. Connecting portion; 145. Base material layer; 146. Adhesive layer; 147. Concave portion;

[0096] V, winding direction; L, length direction; X, second direction; Y, thickness direction; Z, first direction. DETAILED DESCRIPTION

[0097] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution 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 part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0098] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0099] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0100] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0101] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0102] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. 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, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0103] The term "plurality" used in the present application refers to two or more (including two).

[0104] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0105] Battery cells may include but are not limited to lithium ion battery cells, sodium ion battery cells, sodium lithium ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium sulfur battery cells, magnesium ion battery cells, nickel metal hydride battery cells, nickel cadmium battery cells, lead storage battery cells, etc.

[0106] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell or a battery cell of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc. There is no particular limitation in the present application.

[0107] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0108] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0109] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are accommodated in the case.

[0110] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0111] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0112] A battery cell generally includes an electrode assembly and a housing, and the electrode assembly is contained in the housing. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed back and forth between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode, which can reduce the risk of short circuit between the positive and negative electrodes, while allowing active ions to pass through.

[0113] The shell is used to encapsulate the electrode assembly and electrolyte and other components. The shell can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell) or an aluminum-plastic film.

[0114] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The negative electrode may be a negative electrode sheet, which may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0115] During the preparation of the electrode (positive electrode or negative electrode), it is usually necessary to cut (such as the electrode slitting process or the tab die cutting process) to form the required size and shape. However, after cutting, the current collector is prone to burrs at the cutting position; during the charging and discharging process of the battery cell, the burrs may pierce the separator and connect the positive and negative electrodes, causing a short circuit risk and affecting the reliability of the battery cell.

[0116] In view of this, an embodiment of the present application provides a technical solution, which blocks the burrs on the end surface of the current collector by arranging an insulating member on the pole piece, thereby reducing the risk of the burrs conducting the positive and negative electrodes and improving the reliability of the battery cell.

[0117] The electrode assembly described in the embodiments of the present application is applicable to a battery cell, a battery, and an electrical device using the battery.

[0118] The battery disclosed in the embodiments of the present application can be used in an electrical device that uses the battery as a power source or in various energy storage systems that use the battery as an energy storage element. The electrical device can be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, and an electric airplane toy, and the like, and the spacecraft can include an airplane, a rocket, a space shuttle, and a spacecraft, and the like.

[0119] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0120] Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application.

[0121] like Figure 1 As shown, a battery 2 is disposed inside the vehicle 1, and the battery 2 may be disposed at the bottom, head, or tail of the vehicle 1. The battery 2 may be used to power the vehicle 1, for example, the battery 2 may be used as an operating power source for the vehicle 1.

[0122] The vehicle 1 may further include a controller 3 and a motor 4 , wherein the controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of starting, navigating, and driving the vehicle 1 .

[0123] In some embodiments of the present application, the battery 2 can not only serve as an operating power source for the vehicle 1, but also serve as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0124] Figure 2 Schematic diagram of an explosion of a battery provided in some embodiments of the present application. Figure 2 As shown, the battery 2 includes a box body 5 and a battery cell 6 , and the battery cell 6 is accommodated in the box body 5 .

[0125] The box 5 is used to accommodate the battery cell 6, and the box 5 can be of various structures. In some embodiments, the box 5 can include a first box portion 5a and a second box portion 5b, the first box portion 5a and the second box portion 5b cover each other, and the first box portion 5a and the second box portion 5b jointly define a storage space 5c for accommodating the battery cell. The second box portion 5b can be a hollow structure with one end open, the first box portion 5a is a plate-like structure, and the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c; the first box portion 5a and the second box portion 5b can also be hollow structures with one side open, and the open side of the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c. Of course, the first box portion 5a and the second box portion 5b can be of various shapes, such as a cylinder, a cuboid, etc.

[0126] In order to improve the sealing performance after the first box body part 5a and the second box body part 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body part 5a and the second box body part 5b.

[0127] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box.

[0128] In the battery 2, the battery cell 6 can be one or more. If there are more than one battery cell 6, the battery cells 6 can be connected in series, in parallel or in mixed connection. Mixed connection means that the battery cells 6 are both connected in series and in parallel. The battery cells 6 can be directly connected in series, in parallel or in mixed connection, and then the whole formed by the battery cells 6 is accommodated in the box 5; of course, the battery cells can also be connected in series, in parallel or in mixed connection to form a battery module, and then the battery modules are connected in series, in parallel or in mixed connection to form a whole, and then accommodated in the box 5.

[0129] Illustratively, a battery cell may be the smallest unit constituting a battery.

[0130] Figure 3 An exploded schematic diagram of a battery cell provided in some embodiments of the present application.

[0131] like Figure 3 As shown, in some embodiments, the battery cell 6 includes a housing 20 and an electrode assembly 10 accommodated in the housing 20 .

[0132] The electrode assembly 10 includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell 6, active ions (such as lithium ions) are inserted and removed back and forth between the positive electrode and the negative electrode. Optionally, the electrode assembly 10 also includes a separator disposed between the positive electrode and the negative electrode, which can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0133] The housing 20 is used to encapsulate the electrode assembly 10 and the electrolyte and other components. The housing 20 can be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing 20), or an aluminum-plastic film.

[0134] In some embodiments, the housing 20 includes a shell 21 and an end cover 22 , the shell 21 has an opening, and the end cover 22 is used to cover the opening.

[0135] The housing 21 is a component used to cooperate with the end cover 22 to form an internal cavity of the battery cell 6. The formed internal cavity can be used to accommodate the electrode assembly 10, electrolyte and other components.

[0136] The housing 21 and the end cap 22 may be independent components. For example, an opening may be provided on the housing 21, and the end cap 22 may cover the opening to form an internal cavity of the battery cell 6.

[0137] The shell 21 can be in various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism shape, etc. Specifically, the shape of the shell 21 can be determined according to the specific shape and size of the electrode assembly 10. The shell 21 can be made of various materials, for example, the material of the shell 21 includes but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum-plastic film, steel-plastic film, etc.

[0138] The shape of the end cap 22 can be adapted to the shape of the shell 21 to match the shell 21. The material of the end cap 22 can be the same as or different from the material of the shell 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 22 is not easily deformed when squeezed and collided, so that the battery cell 6 can have a higher structural strength and the reliability performance can also be improved.

[0139] The end cover 22 is connected to the housing 21 by welding, bonding, clamping or other methods.

[0140] The housing 21 may be open at one end or at both ends. In some examples, the housing 21 may be a structure with an opening at one end, and an end cap 22 is provided and covers the housing 21. In other examples, the housing 21 may be a structure with openings at both ends, and two end caps 22 are provided, and the two end caps 22 cover the two openings of the housing 21 respectively.

[0141] In some embodiments, the battery cell 6 includes an electrode terminal 30 . The electrode terminal 30 is electrically connected to the electrode assembly 10 to output or input electrical energy of the battery cell 6 .

[0142] In some embodiments, the battery cell 6 further includes an electrolyte contained in the housing 20. The electrolyte plays a role in conducting ions between the positive and negative electrodes and can be in liquid, gel or solid state.

[0143] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0144] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0145] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0146] In some embodiments, the gel electrolyte includes a polymer as an electrolyte skeleton network and an ionic liquid-lithium salt.

[0147] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0148] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, and the like.

[0149] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0150] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0151] Figure 4 A schematic top view of an electrode assembly provided in some embodiments of the present application; Figure 5 for Figure 4 Schematic diagram of the local section taken along the AA direction.

[0152] Reference Figure 4 and Figure 5 The electrode assembly 10 of the embodiment of the present application includes a first pole piece 11 and a second pole piece 12 with opposite polarities.

[0153] Exemplarily, one of the first pole piece 11 and the second pole piece 12 is a positive pole piece, and the other is a negative pole piece.

[0154] In some embodiments, the positive electrode sheet may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.

[0155] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is disposed on any one or both of the two facing surfaces of the positive electrode current collector.

[0156] As an example, the positive electrode current collector may be carbon, metal foil or composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, titanium, silver surface treated aluminum or stainless steel, etc. may be used. The composite current collector may include a polymer material base and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0157] As an example, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may include at least one of the following materials: a lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds. The positive electrode active material may also use other traditional materials that can be used as a positive electrode active material layer of a battery. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2) and its modified compounds, etc.

[0158] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0159] As an example, the negative electrode current collector can be a metal foil, a foamed metal or a composite current collector. For example, as a metal foil, aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel or titanium with a silver surface treatment can be used. The foamed metal can be a nickel foam, a copper foam, an aluminum foam, an alloy foam, or a carbon foam. The composite current collector can include a polymer material base and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0160] As an example, the negative electrode active material layer includes a negative electrode active material. The negative electrode active material may adopt a negative electrode active material for a battery cell that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may include at least one of elemental tin, tin oxide compounds, and tin alloys. The negative electrode active material of the present application may also use other traditional materials that can be used as negative electrode active materials for batteries. These negative electrode active materials may be used alone or in combination of two or more.

[0161] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0162] In some embodiments, the electrode assembly 10 further includes a separator 13, which is used to separate the first electrode sheet 11 from the second electrode sheet 12. The separator 13 can reduce the risk of short circuit between the positive and negative electrodes, while allowing active ions to pass through.

[0163] In some embodiments, the separator 13 includes a separator. The separator of the present application can be any known porous separator with good chemical stability and mechanical stability.

[0164] As an example, the main material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator 13 may be a separate component located between the positive and negative electrodes, or it may be attached to the surface of the positive and negative electrodes.

[0165] In some embodiments, the separator 13 is a solid electrolyte. The solid electrolyte is disposed between the positive electrode sheet and the negative electrode sheet, and plays the role of transmitting ions and isolating the positive and negative electrodes.

[0166] In some embodiments, the electrode assembly 10 is a wound structure. Exemplarily, the first pole piece 11 and the second pole piece 12 are both strip-shaped structures, and the first pole piece 11, the separator 13 and the second pole piece 12 are wound into a wound structure.

[0167] In some embodiments, the electrode assembly 10 is a laminate structure.

[0168] As an example, a plurality of the first pole pieces 11 and a plurality of the second pole pieces 12 may be provided respectively, and the plurality of first pole pieces 11 and the plurality of second pole pieces 12 may be alternately stacked.

[0169] As an example, a plurality of first pole sheets 11 may be provided, and the second pole sheet 12 may be folded to form a plurality of stacked folded segments, with one first pole sheet 11 being sandwiched between adjacent folded segments.

[0170] As an example, the first pole piece 11 and the second pole piece 12 are both folded to form a plurality of stacked folded segments.

[0171] As an example, a plurality of spacers 13 may be provided, each spacer 13 being provided between any adjacent first pole pieces 11 or second pole pieces 12 .

[0172] As an example, the spacer 13 may be disposed continuously, and disposed between any adjacent first pole pieces 11 or second pole pieces 12 by folding or winding.

[0173] In some embodiments, the shape of the electrode assembly 10 can be cylindrical, flat, or polygonal.

[0174] Figure 6 A schematic diagram of a first pole piece of an electrode assembly provided in some embodiments of the present application in a flattened state; Figure 7 for Figure 6 A schematic cross-sectional view taken along the EE direction; Figure 8 for Figure 6 Schematic diagram from another angle; Fig. 9 for Figure 6 A schematic diagram of a first pole piece after being connected to an insulating member is shown, wherein a portion of the first pole piece covered by the insulating member is shown by a dotted line; Fig.10 A schematic diagram of an insulating member of an electrode assembly provided in some embodiments of the present application; Fig.11 for Fig. 9 A schematic cross-sectional view taken along the BB direction; Fig.12 for Fig. 9 Cross-sectional view along CC direction; Fig.13 for Fig. 9A schematic diagram of the first pole piece and the insulating member shown at another angle; Fig.14 A schematic diagram of the insulating layer of an electrode assembly in a flattened state provided in some embodiments of the present application, wherein the boundary between the insulating body and the connecting portion is shown by a dotted line.

[0175] Please refer to Figures 4 to 14 , an embodiment of the present application provides an electrode assembly 10, which includes a first pole piece 11 and a second pole piece 12 with opposite polarities.

[0176] The first pole piece 11 includes a first pole piece body 111, which includes a first current collecting body 112 and a first active material layer 113. The first current collecting body 112 includes two first surfaces 1121 arranged opposite to each other along its own thickness direction Y and a first end face 1122 connecting the two first surfaces 1121. The first active material layer 113 is arranged on the first surface 1121.

[0177] In some examples, the first electrode sheet 11 is a positive electrode sheet, the positive electrode current collector may include a first current collector body 112, and the first active material layer 113 is a positive electrode active material layer. In other examples, the first electrode sheet 11 is a negative electrode sheet, the negative electrode current collector includes a first current collector body 112, and the first active material layer 113 is a negative electrode active material layer.

[0178] The first active material layer 113 may be disposed entirely on the first surface 1121. Alternatively, a portion of the first active material layer 113 may also be disposed at other locations. For example, the first electrode sheet 11 further includes a first electrode tab 114 connected to the first current collector 112, and a portion of the first active material layer 113 may be disposed at the root of the first electrode tab 114 close to the first current collector 112.

[0179] In the embodiment of the present application, the first active material layer 113 may be disposed on one first surface 1121 , or may be disposed on both first surfaces 1121 .

[0180] Exemplarily, the first current collecting body 112 has a relatively small thickness, the first end face 1122 is relatively small in the thickness direction Y of the first pole piece body 111, and the first end face 1122 can be approximately a line. Optionally, the thickness of the first current collecting body 112 is 2 μm-30 μm. Optionally, the thickness of the first current collecting body 112 is 5 μm-15 μm.

[0181] Exemplarily, at least a portion of the first end surface 1122 is formed during a cutting process of the first pole piece 11 .

[0182] In some embodiments, the electrode assembly 10 further includes an insulating member 14 connected to the first electrode body 111 , and at least a portion of the insulating member 14 is disposed outside the first end surface 1122 along a first direction Z, and the first direction Z is perpendicular to the thickness direction Y.

[0183] Exemplarily, “at least part of the insulating member 14 is disposed on the outer side of the first end face 1122 along the first direction Z” does not require that the insulating member 14 overlaps with the first end face 1122 in the first direction Z, as long as at least part of the insulating member 14 protrudes from the first end face 1122 in the first direction Z.

[0184] Exemplarily, at least a portion of the first end surface 1122 overlaps with the insulating member 14 in the thickness direction.

[0185] The first current collecting body 112 may have one first end surface 1122 or may have multiple first end surfaces 1122. Optionally, the first current collecting body 112 has multiple first end surfaces 1122, and an insulating member 14 is correspondingly disposed on the outer side of each first end surface 1122.

[0186] The insulating member 14 may be directly connected to the first active material layer 113 , may be directly connected to the first current collecting body 112 , or may be directly connected to both the first active material layer 113 and the first current collecting body 112 .

[0187] The insulating member 14 may be an integrally formed structure. Alternatively, the insulating member 14 may be assembled from at least two independently formed components.

[0188] The number of the insulating member 14 may be one or more.

[0189] The insulating member 14 can be connected to the first pole piece body 111 in a variety of ways. For example, the insulating member 14 can be connected to the first pole piece body 111 by bonding; alternatively, the insulating member 14 can be connected to the first pole piece body 111 by attachment instead of bonding to the first pole piece body 111.

[0190] In the embodiment of the present application, the insulating member 14 can separate the burrs on the first end surface 1122 from the second pole piece 12 , thereby reducing the risk of conduction between the burrs and the second pole piece 12 , reducing the possibility of thermal runaway caused by short circuit, and improving the reliability of the battery cell 6 .

[0191] Exemplarily, the insulating member 14 can separate the burr from the isolating member 13 , thereby reducing the risk of the burr piercing the isolating member 13 .

[0192] In some embodiments, the insulating member 14 includes two first insulating portions 141 and a second insulating portion 142. The two first insulating portions 141 are respectively located on both sides of the first pole piece body 111 along the thickness direction Y and connected to the first pole piece body 111. The second insulating portion 142 connects the two first insulating portions 141 and is disposed outside the first end surface 1122 along the first direction Z.

[0193] Exemplarily, in the thickness direction Y, the projection of the first insulating portion 141 is located within the projection of the first pole piece body 111 , and the projection of the second insulating portion 142 does not overlap with the projection of the first pole piece body 111 .

[0194] The shapes of the two first insulating parts 141 may be the same or different.

[0195] The first insulating portion 141 may be connected to the first active material layer 113 or may be connected to the first current collecting body 112 .

[0196] By providing two first insulating portions 141, the connection area between the insulating member 14 and the first pole piece body 111 can be increased, reducing the risk of the insulating member 14 falling off. The second insulating portion 142 can separate the burrs on the first end surface 1122 from the second pole piece, thereby reducing the risk of short circuit.

[0197] In some embodiments, the second insulating portion 142 covers at least a portion of the first end surface 1122 to cover burrs on the first end surface 1122 , thereby further reducing the risk of short circuit.

[0198] In the first direction, the second insulating portion 142 at least partially overlaps the first end surface 1122 to cover at least a portion of the first end surface 1122 .

[0199] The second insulating portion 142 may completely cover the first end surface 1122 , or may only cover a portion of the first end surface 1122 .

[0200] In some embodiments, the first pole piece 11 further includes a first pole tab 114 , and the first pole tab 114 is connected to the first current collecting body 112 .

[0201] In some examples, the first current collecting body 112 and the first electrode tab 114 may be an integrally formed structure; in other examples, the first electrode tab 114 and the first current collecting body 112 may be formed independently and connected by welding or other means.

[0202] There may be one or more first electrode tabs 114 .

[0203] In some embodiments, the first pole tab 114 is integrally formed with the first current collector 112. For example, the first pole tab 114 can be formed by a die-cutting process; during the forming process of the first pole piece, a portion of the first pole piece is removed by the die-cutting process to form the protruding first pole tab 114.

[0204] In some embodiments, the first end surface 1122 is located at one end of the first current collecting body 112 along the first direction Z.

[0205] Illustratively, after the first pole piece 11 is flattened, the first end surface 1122 may be located at one end of the first current collecting body 112 along the length direction L of the first pole piece 11 , or may be located at one end of the first current collecting body 112 along the width direction of the first pole piece body 111 .

[0206] In some embodiments, the first current collecting body 112 has two first end surfaces 1122 that are opposite to each other along the first direction Z. An insulating member 14 is disposed on at least one of the first end surfaces 1122 .

[0207] In some embodiments, the electrode assembly 10 is a wound structure. Optionally, the first direction Z may be parallel to the winding axis of the electrode assembly 10 .

[0208] In some embodiments, the first pole piece 11 further includes a first pole tab 114 , and the first pole tab 114 extends outward along the first direction Z from the first end surface 1122 .

[0209] Exemplarily, the first current collector 112 has two first end surfaces 1122, and all the first pole tabs 114 extend outward from the same first end surface 1122. Alternatively, there are multiple first pole tabs 114, a portion of the first pole tabs 114 extend outward from one first end surface 1122, and another portion of the first pole tabs 114 extend outward from another first end surface 1122.

[0210] In some embodiments, the first electrode tab 114 extends outward from the first end surface 1122 along the first direction Z and passes through the second insulating portion 142 .

[0211] The second insulating portion 142 can shield burrs formed on the first end surface 1122 during the molding process of the first electrode tab 114 , thereby reducing the risk of short circuit.

[0212] In some embodiments, the first end surface 1122 includes a tab lead-out region 1122 a and a non-tab lead-out region 1122 b , and the first tab 114 extends only from the tab lead-out region 1122 a and protrudes from the second insulating portion 142 along the first direction Z away from the first current collecting body 112 .

[0213] There may be one or more tab lead-out regions 1122a. Exemplarily, the number of tab lead-out regions 1122a corresponds to the number of first tabs 114. After the first tabs 114 are cut off, the tab lead-out regions 1122a are exposed.

[0214] The number of non-tab lead-out regions 1122b may be one or more.

[0215] In some examples, there are multiple tab lead-out regions 1122a and multiple non-tab lead-out regions 1122b, and the multiple tab lead-out regions 1122a and the multiple non-tab lead-out regions 1122b are alternately arranged.

[0216] The first electrode tab 114 protrudes from the second insulating portion 142 to facilitate connection with other conductive structures, thereby reducing the risk of interference between the second insulating portion 142 and the conductive structure.

[0217] In some embodiments, the second insulating portion 142 covers at least a portion of the non-tab lead-out region 1122b. The second insulating portion 142 can separate the burrs on the non-tab lead-out region 1122b from the second pole piece, thereby reducing the risk of short circuit.

[0218] In some embodiments, the second insulating portion 142 completely covers the non-tab lead-out region 1122b. The second insulating portion 142 can completely cover the non-tab lead-out region 1122b, thereby covering the burrs of the non-tab lead-out region 1122b and reducing the risk of short circuit.

[0219] In some embodiments, the second insulating portion 142 has a channel 142 a , the first electrode tab 114 passes through the channel 142 a , and the second insulating portion 142 completely covers the non-electrode tab lead-out region 1122 b .

[0220] By providing the channel 142 a , the first pole tab 114 can be avoided, thereby reducing the risk of interference between the insulating member 14 and the first pole tab 114 .

[0221] In some embodiments, the second insulating portion 142 includes a first extension portion 1421 and a second extension portion 1422. The first extension portion 1421 is arranged on the outer side of the non-pole tab lead-out area 1122b along the first direction Z, and the second extension portion 1422 is arranged on the outer side of the pole tab lead-out area 1122a along the first direction Z and covers at least a portion of the first pole tab along the thickness direction Y.

[0222] Exemplarily, a plane parallel to the first direction Z and passing through the boundary between the non-tab lead-out region 1122 b and the tab lead-out region 1122 a may be the interface between the first extension portion 1421 and the second extension portion 1422 .

[0223] In the first direction Z, the size of the first extending portion 1421 and the size of the second extending portion 1422 may be equal or unequal.

[0224] The second extension portion 1422 can support the root of the first pole tab 114 near the pole tab lead-out region 1122a, reducing the risk of the first pole tab 114 being inserted upside down between the first pole piece 11 and the second pole piece 12 when being bent, thereby reducing the risk of short circuit and improving reliability.

[0225] Illustratively, in the battery cell 6, in order to save the space occupied by the first pole lug 114, the first pole lug 114 can be bent; during the bending process, the root of the first pole lug 114 may be deformed and inserted inverted between the first pole piece 11 and the second pole piece 12; the second extension portion 1422 can support the root of the first pole lug 114 close to the pole lug lead-out area 1122a, thereby reducing the risk of the first pole lug 114 being inserted inverted between the first pole piece 11 and the second pole piece 12 when being bent.

[0226] In some embodiments, the first extension portion 1421 covers the non-tab lead-out region 1122 b along the first direction Z to shield burrs on the non-tab lead-out region 1122 b.

[0227] In some embodiments, a dimension D2 of the first extension portion 1421 along the first direction Z is equal to a dimension D1 of the second extension portion 1422 along the first direction Z.

[0228] The second insulating portion 142 is configured with a uniform width as a whole, and is easy to shape.

[0229] In some embodiments, D1 is 2 mm-10 mm.

[0230] Optionally, D1 is 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0231] In the embodiment of the present application, D1 is limited to be greater than or equal to 2 mm, so as to provide effective support for the first pole ear 114, reduce the risk of the first pole ear 114 being inserted upside down between the first pole piece 11 and the second pole piece 12, and improve reliability. In the embodiment of the present application, D1 is limited to be less than or equal to 10 mm, so as to reduce the volume and weight of the insulating member 14 and improve the energy density.

[0232] In some embodiments, in the first direction Z, the dimension W3 of the root region of the first electrode tab 114 covered by the second extension portion 1422 is greater than or equal to 0.2 times the dimension W4 of the first electrode tab 114 and less than or equal to 0.6 times the dimension W4 of the first electrode tab 114. Exemplarily, 0.2≤W3 / W4≤0.6.

[0233] W3 / W4 is limited to be greater than or equal to 0.2 to provide effective support for the first pole ear 114, reduce the risk of the first pole ear 114 being inserted upside down between the first pole piece 11 and the second pole piece 12, and improve reliability. In the embodiment of the present application, W3 / W4 is limited to be less than or equal to 0.6 to reduce the volume and weight of the insulating member 14 and improve the energy density.

[0234] In some embodiments, D1 is equal to W3.

[0235] In some embodiments, the first electrode sheet 11 and the second electrode sheet 12 are wound. Exemplarily, the electrode assembly 10 is a wound structure.

[0236] In some embodiments, the first pole piece 11 includes a plurality of first pole tabs 114 , and the plurality of first pole tabs 114 are arranged at intervals in a winding direction V of the first pole piece 11 .

[0237] In some embodiments, the first extension portion 1421 is connected to the second extension portion 1422 .

[0238] In some embodiments, the second insulating portion 142 connects adjacent first pole tabs 114. When the first pole tabs 114 are bent, the roots of the adjacent first pole tabs 114 can be restricted from deforming each other by the second insulating portion 142, thereby reducing the risk of the first pole tabs 114 being inserted inverted between the first pole piece 11 and the second pole piece 12 and improving reliability.

[0239] In some embodiments, the second insulating portion 142 connects the plurality of first tabs 114 .

[0240] In some embodiments, the first insulating portion 141 is connected to the first active material layer 113 , which can increase the connection area between the insulating member 14 and the first pole piece body 111 and reduce the risk of the insulating member 14 falling off.

[0241] The first insulating portion 141 and the first active material layer 113 may or may not overlap in the thickness direction Y.

[0242] In some embodiments, at least a portion of the first insulating portion 141 overlaps with the first active material layer 113 in the thickness direction Y and is connected to the first active material layer 113 .

[0243] The embodiment of the present application can further increase the connection area between the first insulating portion 141 and the first pole piece body 111 .

[0244] In some embodiments, the width of the region where the first insulating portion 141 overlaps the first active material layer 113 is W1, and W1 is 0.1 mm-1 mm.

[0245] Optionally, W1 is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm.

[0246] W1 is limited to be greater than or equal to 0.1 mm to increase the connection area between the first insulating portion 141 and the first active material layer 113 and reduce the risk of the insulating member 14 falling off. W1 is limited to be less than or equal to 1 mm to reduce the amount of the insulating member 14, reduce the barrier of the first insulating portion 141 to the active ions, and reduce the capacity loss of the battery cell 6.

[0247] In some embodiments, the first active material layer 113 includes a main body region 1131 arranged along the first direction Z and a thinning region 1132 connected to the main body region 1131, the thinning region 1132 is located on one side of the main body region 1131 close to the first end surface 1122 along the first direction Z, and the thickness of at least part of the thinning region 1132 is less than the thickness of the main body region 1131. The first insulating portion 141 covers at least part of the thinning region 1132 along the thickness direction Y.

[0248] Exemplarily, one end of the thinned region 1132 close to the main region 1131 is directly connected to the main region 1131. In some examples, the thickness of the end of the thinned region 1132 close to the main region 1131 is less than the thickness of the end of the main region 1131 close to the thinned region 1132, and a step is formed at the connection between the thinned region 1132 and the main region 1131. In other examples, the thickness of the end of the thinned region 1132 close to the main region 1131 is less than the thickness of the main region 1131 and is equal to the thickness of the end of the thinned region 1132.

[0249] Exemplarily, the main body region 1131 is substantially a structure of equal thickness. The average thickness of the thinned region 1132 is less than the thickness of the main body region 1131 .

[0250] During the molding process of the first electrode sheet 11, the first active material layer 113 needs to be rolled to increase the compaction density of the first active material layer 113. The present application can reduce the pressure on the edge of the first active material layer 113 by setting the thinning area 1132, and reduce the risk of cracking of the first current collector 112. The first insulating portion 141 is arranged in the space on one side of the thinning area 1132 along the thickness direction Y, which can improve the space utilization.

[0251] In some embodiments, the thickness of one end of the thinning region 1132 close to the main region 1131 is equal to the thickness of one end of the main region 1131 close to the thinning region 1132. The thickness of the thinning region 1132 gradually decreases in a direction away from the main region 1131. The thickness of the thinning region 1132 changes smoothly, thereby reducing the risk of forming steps on the first active material layer 113 and reducing stress concentration.

[0252] In some embodiments, in the first direction Z, the first insulating portion 141 and the main body region 1131 are spaced apart so that the main body region 1131 and the first insulating portion 141 do not overlap in the thickness direction Y, thereby improving space utilization.

[0253] In addition, in the thickness direction Y, the main body region 1131 and the first insulating portion 141 do not overlap, and the first insulating portion 141 is unlikely to block the transmission of ions between the main body region 1131 and the second electrode sheet, thereby reducing the capacity loss of the battery cell.

[0254] In some embodiments, along the direction from the first current collecting body 112 to the first active material layer 113 , the first insulating portion 141 does not extend beyond the surface of the body region 1131 away from the first current collecting body 112 .

[0255] The embodiment of the present application can reduce the additional space occupied by the first insulating portion 141 in the thickness direction Y, improve space utilization, and reduce the risk of the first insulating portion 141 squeezing the second pole piece 12 .

[0256] In some embodiments, the thickness t1 of the end of the thinned region 1132 away from the main region 1131 is less than or equal to 0.5 times the thickness t2 of the main region 1131. Exemplarily, t1 / t2≤0.5. Optionally, t1 / t2≤1 / 3.

[0257] The end of the thinning area 1132 away from the main area 1131 has a smaller thickness, which can reduce the area covered by the second insulating part 142, reduce the force at the connection between the first insulating part 141 and the second insulating part 142, and reduce the risk of cracking and falling off of the insulating part 14.

[0258] In some embodiments, the first current collecting body 112 further includes two second end surfaces 1123 , which are respectively disposed at two ends of the first end surface 1122 , and each second end surface 1123 connects the two first surfaces 1121 .

[0259] Optionally, the two second end surfaces 1123 may be located at two ends of the first current collecting body 112 along the winding direction V, respectively.

[0260] In some embodiments, the insulating member 14 further includes a third insulating portion 143 , which is connected to the first insulating portion 141 and the second insulating portion 142 and covers a portion of the second end surface 1123 .

[0261] In the thickness direction Y, the third insulating portion 143 does not overlap with the first pole piece body 111 .

[0262] Optionally, the third insulating portion 143 may include a first region and a second region arranged along the first direction Z, the first region connecting the two first insulating portions 141, and the second region being located on one side of the second insulating portion 142 along the winding direction V and connected to the second insulating portion 142. The interface between the second region and the second insulating portion 142 may be coplanar with the second end surface 1123.

[0263] The third insulating portion 143 can cover the burrs on the second end surface 1123, thereby reducing the risk of short circuit and improving reliability. By providing the third insulating portion 143, the risk of exposing the first end surface 1122 due to assembly error can also be reduced.

[0264] In some embodiments, there are two third insulating parts 143 .

[0265] In some embodiments, the electrode assembly 10 further includes a separator 13, which is used to separate the first electrode sheet 11 from the second electrode sheet 12. The first electrode sheet 11, the separator 13, and the second electrode sheet 12 are wound. In the winding direction V of the first electrode sheet, both ends of the insulating member 14 do not exceed the separator 13.

[0266] For example, Figure 4 As shown, the positive direction of the winding direction V is counterclockwise, and the negative direction of the winding direction V is clockwise. In the positive direction of the winding direction V, the insulating member 14 does not exceed the tail end of the isolating member 13; in the negative direction of the winding direction V, the insulating member 14 does not exceed the head end of the isolating member 13.

[0267] The isolation member 13 can restrain the insulating member 14 , maintain the fit between the insulating member 14 and the first pole piece body 111 , and reduce the risk of the insulating member 14 falling off the first pole piece body 111 .

[0268] Exemplarily, in the positive direction of the winding direction V, the tail end of the isolating member 13 exceeds one third insulating portion 143 of the insulating member 14 . In the negative direction of the winding direction V, the head end of the isolating member 13 exceeds another third insulating portion 143 of the insulating member 14 .

[0269] The separator 13 can constrain the third insulating portion 143 , reducing the risk of separation of the two insulating layers of the third insulating portion 143 when soaked in electrolyte.

[0270] In some embodiments, the insulating member 14 includes two independently formed insulating layers 144, and the insulating layer 144 includes an insulating body 144a and a connecting portion 144b connected to the insulating body 144a; in the thickness direction Y, the insulating body 144a overlaps with the first pole piece body 111, and the connecting portion 144b does not overlap with the first pole piece body 111. The insulating bodies 144a of the two insulating layers 144 respectively form two first insulating portions 141; the connecting portions 144b of the two insulating layers 144 are stacked and connected to form a second insulating portion 142.

[0271] Optionally, the connection portion 144 b of the two insulating layers 144 further forms a third insulating portion 143 .

[0272] The two insulating layers 144 can be attached to the first pole piece body 111 from both sides, thereby forming the insulating member 14. The embodiment of the present application can simplify the assembly process.

[0273] In some embodiments, t1 / t2≤0.5. The end of the thinned region 1132 away from the main region 1131 has a smaller thickness. When attaching the insulating layer 144, the insulating layer 144 is bent less at the end of the thinned region 1132 away from the main region 1131, which helps to reduce the risk of a gap between the two insulating layers 144 and improve the connection strength of the two insulating layers 144.

[0274] In some embodiments, the thickness of the insulating layer 144 is 7 μm-30 μm. Optionally, the thickness of the insulating layer 144 is 4 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 20 μm, 25 μm or 30 μm.

[0275] Limiting the thickness of the insulating layer 144 to be greater than or equal to 7 μm can reduce the risk of the insulating layer 144 being pierced by burrs and improve reliability. Limiting the thickness of the insulating layer 144 to be less than or equal to 30 μm can reduce the space and weight occupied by the insulating layer 144 and reduce the loss of energy density of the battery cell 6.

[0276] In some embodiments, the difference between the thickness of the insulating layer 144 and the thickness of the first current collecting body 112 has an insulating value of no greater than 10 μm.

[0277] Exemplarily, the thickness of the insulating layer 144 is t3, the thickness of the first current collecting body 112 is t4, and |t3-t4|≤10 μm.

[0278] The larger t3 is, the less likely the insulating layer 144 is to be pierced by the burrs; correspondingly, the larger the space and weight occupied by the insulating layer 144. The larger t4 is, the stronger the current carrying capacity of the first current collecting body 112 is, but the more serious the burrs generated by the first current collecting body 112 are, the easier it is for the burrs to pierce the insulating layer 144.

[0279] In the embodiment of the present application, the insulation value of the difference between the thickness of the insulating layer 144 and the thickness of the first current collecting body 112 is limited to no more than 10 μm. On the premise that the overcurrent of the first current collecting body 112 meets the requirements, the risk of the insulating layer 144 being pierced by burrs is reduced, the weight and space occupied by the insulating layer 144 are reduced, and the energy density is improved.

[0280] In some embodiments, the difference between the thickness of the insulating layer 144 and the thickness of the first current collecting body 112 has an insulation value of no greater than 5 μm, so as to further reduce the difference between the thickness of the insulating layer 144 and the first current collecting body 112 .

[0281] In some embodiments, | t3 − t4 |≦1 μm, so as to further reduce the difference in thickness between the insulating layer 144 and the first current collecting body 112 .

[0282] In some embodiments, the first end surface 1122 includes a tab lead-out region 1122a and a non-tab lead-out region 1122b, and the first tab 114 extends only from the tab lead-out region 1122a and protrudes from the second insulating portion 142 in a direction away from the first current collector 112. The two connecting portions 144b are directly connected to the non-overlapping portion of the first tab 114 and form a first extension portion 1421, and the first extension portion 1421 covers the non-tab lead-out region 1122b along the first direction Z. The two connecting portions 144b overlap the first tab 114 to form a second extension portion 1422, and cover at least part of the first tab along the thickness direction Y.

[0283] The first extension portion 1421 can cover the non-tab lead-out area 1122 b , thereby shielding the burrs on the non-tab lead-out area 1122 b and reducing the risk of short circuit.

[0284] In some embodiments, a dimension of the first extension portion 1421 along the first direction Z is equal to a dimension of the second extension portion 1422 along the first direction Z.

[0285] In some embodiments, the portion of the connection portion 144b that overlaps with the first pole tab 114 has a dimension D3 in the first direction Z, and the portion of the connection portion 144b that does not overlap with the first pole tab 114 protrudes beyond the non-pole tab lead-out area 1122b in the first direction Z has a dimension D4, and D3 is equal to D4.

[0286] Exemplarily, D3 is equal to D1, and D4 is equal to D2.

[0287] The area where the two connecting portions 144 b are directly connected has a larger size along the first direction Z, thereby increasing the connection strength of the two connecting portions 144 b and improving the reliability of the connecting portions 144 b covering the non-tab lead-out area 1122 b.

[0288] In some embodiments, the insulating layer 144 is rectangular in a flattened state.

[0289] In some embodiments, the width of the insulating layer 144 is 5 mm-20 mm in the first direction Z. Optionally, the width of the insulating layer 144 is 5 mm, 6 mm, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm or 20 mm.

[0290] In some embodiments, the first current collector 112 includes two first end surfaces 1122 disposed opposite to each other along a first direction Z, and the first direction Z is perpendicular to a thickness direction Y of the first electrode body 111. The electrode assembly 10 includes two insulating members 14, which are disposed outside the two first end surfaces 1122, respectively.

[0291] The two insulating members 14 can separate the burrs on the two first end surfaces 1122 from the second pole piece, thereby further reducing the risk of short circuit.

[0292] In some embodiments, the second pole piece 12 includes a second pole piece body 121, and the second pole piece body 121 is stacked with the first pole piece body 111. The second pole piece body 121 includes a second current collecting body 122 and a second active material layer 123, the second current collecting body 122 includes two second surfaces 1221 arranged opposite to each other and a third end face 1222 connecting the two second surfaces 1221, and the second active material layer 123 is arranged on the second surface 1221.

[0293] In some examples, the second electrode sheet 12 is a positive electrode sheet, the positive electrode current collector may include a second current collector body 122, and the second active material layer 123 is a positive electrode active material layer. In other examples, the second electrode sheet 12 is a negative electrode sheet, the negative electrode current collector includes a second current collector body 122, and the second active material layer 123 is a negative electrode active material layer.

[0294] In the embodiment of the present application, the second active material layer 123 may be disposed on one second surface 1221 , or may be disposed on both second surfaces 1221 .

[0295] In some embodiments, the first end surface 1122 is located at one end of the first current collector 112 along the first direction Z, and the third end surface 1222 is located at one end of the second current collector 122 along the first direction Z. In the thickness direction Y, the insulating member 14 separates the third end surface 1222 from the first pole piece 11 .

[0296] Exemplarily, there are two first end faces 1122 and two third end faces 1222. One insulating member 14 separates the third end face 1222 near one first end face 1122 from the first pole piece 11, and another insulating member 14 separates another third end face 1222 near another first end face 1122 from the first pole piece 11.

[0297] In the embodiment of the present application, the first insulating portion 141 may separate the third end surface 1222 from the first pole piece 11 , or the second insulating portion 142 may separate the third end surface 1222 from the first pole piece 11 .

[0298] The insulating member 14 can also separate the burrs on the third end surface 1222 from the first pole piece 11 , thereby reducing the risk of the burrs on the third end surface 1222 being electrically connected to the first pole piece 11 , reducing the possibility of thermal runaway caused by short circuit, and improving the reliability of the battery cell 6 .

[0299] In some embodiments, the first electrode sheet 11 is a positive electrode sheet, and the second electrode sheet 12 is a negative electrode sheet. In the first direction Z, both ends of the second active material layer 123 extend beyond the first electrode sheet body 111 .

[0300] The insulating member 14 shields at least a portion of the first end surface 1122, and even if the second active material layer 123 overlaps with the first end surface 1122 in the stacking direction, it is not easy to contact the burrs on the first end surface 1122. The second active material layer 123 can provide more embedding sites for active ions released from the first active material layer 113, thereby reducing the risk of active ion precipitation, improving the cycle performance of the battery cell 6, and improving reliability.

[0301] In some embodiments, the electrode assembly 10 further includes a separator 13, which is used to separate the first electrode body 111 from the second electrode 12. In the first direction Z, an end of the second insulating portion 142 away from the first insulating portion 141 does not extend beyond the separator 13.

[0302] The embodiment of the present application can reduce the usage of the second insulating part 142, reduce the weight and space occupied by the second insulating part 142, and improve the energy density.

[0303] In some embodiments, the melting point of the insulating member 14 is 95°C-150°C.

[0304] Optionally, the melting point of the insulating member 14 is 95°C, 100°C, 110°C, 120°C, 130°C, 140°C, 145°C or 150°C.

[0305] During the charge and discharge process of the battery cell 6, the first current collecting body 112 generates heat. The insulating member 14 has a relatively high melting point, which can reduce the risk of the insulating member 14 being softened or falling off due to heat, thereby improving reliability.

[0306] In some embodiments, the insulating member 14 includes a colloid including at least one of ethylene and copolymers thereof, polyolefins, polyesters, polyurethanes, polyamides, styrene and block copolymers thereof.

[0307] The colloid has a high bonding strength and is not easy to fall off from the first pole piece body 111 .

[0308] Optionally, the colloid may be a hot melt colloid. The insulating member 14 may be a hot melt adhesive film.

[0309] Optionally, during the production process of the first pole piece 11 , colloid may be directly coated on the first pole piece 11 , and the colloid is cured to form the insulating member 14 .

[0310] In some embodiments, the elastic modulus of the insulating member 14 is 500 MPa-3000 MPa.

[0311] In some examples, the insulating member 14 is an integral structure, and the elastic modulus of the insulating member 14 is 500 Mpa-3000 Mpa. In other examples, the insulating member 14 includes two insulating layers 144 , and the elastic modulus of the insulating member 14 refers to the elastic modulus of the insulating layer 144 .

[0312] As an example, the elastic modulus of the insulating member 14 may be 500 MPa, 600 MPa, 700 MPa, 770 MPa, 800 MPa, 900 MPa, 1000 MPa, 1200 MPa, 1300 MPa, 1320 MPa, 1400 MPa, 1500 MPa, 1800 MPa, 2000 MPa, 2200 MPa, 2500 MPa, 2600 MPa, 2800 MPa or 3000 MPa.

[0313] The insulating member 14 has a relatively high elastic modulus, which can provide support for the first pole lug 114 , reduce the risk of the root of the first pole lug 114 being inserted inverted between the first pole piece 11 and the second pole piece 12 , and improve reliability.

[0314] As an example, the elastic modulus of the insulating member 14 can be tested with reference to the national standard GBT 22315-2008 “Test method for elastic modulus and Poisson's ratio of metallic materials”.

[0315] In some embodiments, the elastic modulus of the insulating member 14 is 770 MPa-1320 MPa.

[0316] In some embodiments, the tensile strength of the insulating member 14 is 949 kgf / cm 2 -1363kgf / cm 2 Optionally, the tensile strength of the insulating member 14 is 949 kgf / cm 2、1000kgf / cm 2 、1050kgf / cm 2 、1100kgf / cm 2 、1150kgf / cm 2 、1200kgf / cm 2 、1250kgf / cm 2 、1300kgf / cm 2 or 1363kgf / cm 2 .

[0317] The insulating member 14 has a high tensile strength and is not easily deformed when subjected to the tensile force from the first pole ear 114 . Accordingly, the insulating member 14 can effectively limit the deformation of the first pole ear 114 , reduce the risk of the root of the first pole ear 114 being inserted inverted between the first pole piece 11 and the second pole piece 12 , and improve reliability.

[0318] As an example, the tensile strength of the insulating member 14 may be tested with reference to the national standard GB / T 228-2002 “Metallic Materials—Room Temperature Tensile Test Method”.

[0319] In some embodiments, the insulating member 14 is connected to the first active material layer 113 , and the peeling strength between the insulating member 14 and the first active material layer 113 is higher than the peeling strength between the first active material layer 113 and the first surface 1121 .

[0320] As an example, the insulating member 14 may be fixed on a tensile testing machine and pulled at 180°. During the pulling process, the first active material layer 113 is peeled off from the first surface 1121 , while the insulating member 14 remains connected to the first active material layer 113 .

[0321] As an example, the peel strength can be tested with reference to "GB / T 2792-2014 Test method for peel strength of adhesive tape".

[0322] In the embodiment of the present application, the peeling strength between the insulating member 14 and the first active material layer 113 is relatively high, thereby reducing the risk of the insulating member 14 falling off and improving reliability.

[0323] In some embodiments, the battery cell 6 includes an electrolyte contained within the housing 20. The insulator 14 remains stable in the electrolyte.

[0324] Exemplarily, after soaking in the electrolyte for 1000 hours, the peel strength between the insulating member 14 and the first active material layer 113 is greater than or equal to 2N / m. Optionally, after soaking in the electrolyte for 1000 hours, the peel strength between the insulating member 14 and the first active material layer 113 is 15N / m-200N / m.

[0325] In some embodiments, the insulating member 14 has good insulation properties, the insulating member 14 will not break down under a voltage of 200 V, and the resistance of the insulating member 14 is greater than or equal to 9999 megohms.

[0326] Fig.15 Schematic diagram of the first pole piece of the electrode assembly in the unfolded state provided in some other embodiments of the present application, wherein the pole tab lead-out area is covered by the first pole tab. Fig.15 Indicated by dotted lines; Fig.16 for Fig.15 A schematic diagram of a first pole piece after being connected to an insulating member is shown, wherein a portion of the first pole piece covered by the insulating member is shown by a dotted line; Fig.17 for Fig.16 Schematic cross-sectional view along the DD direction.

[0327] Reference Figures 15 to 17 In some embodiments, the first surface 1121 includes a coated area 1121a and an uncoated area 1121b arranged along the first direction Z, one end of the uncoated area 1121b is connected to the first end surface 1122, and the other end is connected to the coated area 1121a, the coated area 1121a is coated with the first active material layer 113, and the uncoated area 1121b is not coated with the first active material layer 113. The first insulating portion 141 is connected to the uncoated area 1121b.

[0328] By providing the uncoated area 1121b, the connection area between the first current collector 112 and the insulating member 14 can be increased, the risk of the insulating member 14 falling off can be reduced, and the reliability can be improved. The first end surface 1122 and the first active material layer 113 are arranged at intervals along the first direction Z, so that the risk of cutting the first active material layer 113 during the cutting process of the first pole piece 11 can be reduced, and the waste of active materials can be reduced.

[0329] In some embodiments, the first current collecting body 112 includes two first end surfaces 1122, one end of the uncoated region 1121b away from the coated region 1121a is connected to one first end surface 1122, and one end of the coated region 1121a away from the uncoated region 1121b is connected to the other first end surface 1122. The first insulating portion 141 of one insulating member 14 is connected to the uncoated region 1121b, and the first insulating portion 141 of the other insulating member 14 is connected to the coated region 1121a.

[0330] In some embodiments, the first insulating portion 141 completely covers the uncoated area 1121 b to reduce the possibility of conduction between the uncoated area 1121 b and the second pole piece 12 , reduce the risk of short circuit, and improve reliability.

[0331] In some embodiments, the absolute value of the difference between the thickness of the insulating layer 144 and the thickness of the first current collecting body 112 is less than or equal to 10 μm, that is, | t3 − t4 | ≤ 10 μm.

[0332] When the insulating layer 144 is bent at the junction of the uncoated area 1121 b and the first end surface 1122 , the insulating layer 144 is not easily punctured by the junction of the uncoated area 1121 b and the first end surface 1122 , and the insulating layer 144 is more likely to be attached to the first end surface 1122 .

[0333] In the first direction Z, the size of the area where the insulating member 14 covers the uncoated area 1121 b is greater than or equal to 1 mm, so as to increase the connection strength between the insulating member 14 and the uncoated area 1121 b and reduce the risk of the insulating member 14 falling off the first pole piece 11 .

[0334] Illustratively, in the first direction Z, the size of the area of ​​the insulating member 14 covering the uncoated area 1121 b is W2. Optionally, W2 is 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm.

[0335] In some embodiments, W2 is less than or equal to 5 mm. W2 is limited to less than or equal to 5 mm to reduce the space and weight occupied by the insulating member 14, reduce the size requirements of the uncoated area 1121 b, increase the area of ​​the coated area 1121 a, and improve the energy density of the battery cell 6.

[0336] In some embodiments, the first pole piece 11 further includes a first pole tab 114 . The first pole tab 114 extends outward from the first end surface 1122 along the first direction Z and passes through the second insulating portion 142 .

[0337] In some embodiments, the first current collecting body 112 has two first end surfaces 1122 , the first electrode tab 114 extends from one first end surface 1122 , and the electrode assembly 10 includes two insulating members 14 , which respectively cover the two first end surfaces 1122 .

[0338] Exemplarily, for the insulating member 14 attached to the first end surface 1122 of the lead-out first pole ear 114, the dimension of the area where the insulating member 14 overlaps with the first active material layer 113 along the first direction Z is 0.5 mm, the dimension of the area where the insulating member 14 overlaps with the uncoated area 1121b along the first direction Z is 3 mm, and the dimension of the second insulating portion 142 along the first direction Z is 4.5 mm.

[0339] For the insulating member 14 attached to the first end surface 1122 where the first electrode tab 114 is not led out, the size of the overlapping area of ​​the insulating member 14 and the first active material layer 113 along the first direction Z is 0.5 mm, and the size of the second insulating portion 142 along the first direction Z is 1.5 mm.

[0340] Fig.18 A schematic diagram of an insulating member provided in some embodiments of the present application before being assembled to a first pole piece.

[0341] Reference Fig.18 In some embodiments, the insulating member 14 is an integrally formed structure, which can enhance the stability of the connection between the insulating member 14 and the first pole piece body 111 .

[0342] In some embodiments, the insulating member 14 defines a channel 142 a for the first electrode tab 114 to pass through.

[0343] For example, before assembling the first pole piece 11 and the insulating member 14, the insulating member 14 may be a flat plate structure. The first pole tab 114 may be placed opposite to the channel 142a of the insulating member 14, and the first pole tab 114 may be passed through the channel 142a. After the insulating member 14 abuts against the first end face 1122, the insulating member 14 is folded to attach the insulating member 14 to the first pole piece body 111.

[0344] Fig.19 A schematic diagram of a first pole piece and an insulating member of an electrode assembly provided in some other embodiments of the present application in an unfolded state, wherein a portion of the first pole piece covered by the insulating member is shown by a dotted line; Fig. 20 for Fig.19 Enlarged diagram of the circle.

[0345] Reference Fig.19 and Fig. 20 In some embodiments, the first extension portion 1421 is provided with a first portion 1421a and a second portion 1421b, the second portion 1421b is connected to the second extension portion 1422, the size of the second portion 1421b along the first direction Z is equal to the size of the second extension portion 1422 along the first direction Z, the first portion 1421a is configured to be formed by setting a recess 147 on the second insulating portion 142, and the size of the first portion 1421a along the first direction Z is smaller than the size of the second extension portion 1422 along the first direction Z.

[0346] By providing the recess 147 , the size of the first portion 1421 a along the first direction Z can be reduced, thereby saving the amount of the insulating member 14 and improving the energy density of the battery cell.

[0347] Fig.21 A schematic diagram of the structure of the insulating component of the electrode assembly provided in some embodiments of the present application.

[0348] Reference Fig.21 In some embodiments, the insulating member 14 includes a substrate layer 145 and an adhesive layer 146 , and the substrate layer 145 is connected to the first pole piece body 111 through the adhesive layer 146 .

[0349] The substrate layer 145 can improve the strength of the insulating member 14 and reduce deformation of the insulating member 14 during attachment. The adhesive layer 146 can bond the substrate layer 145 to the first pole piece body 111 to reduce the risk of the substrate layer 145 falling off from the first pole piece body 111.

[0350] In some embodiments, the substrate layer 145 includes at least one of polyethylene terephthalate (PET), polypropylene, polyethylene, and block copolymers thereof.

[0351] In some embodiments, the adhesive layer 146 includes at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene, or butyl rubber.

[0352] In some embodiments, the insulating member 14 includes two insulating layers 144, each of which includes a base material layer 145 and an adhesive layer 146. The adhesive layers 146 of the two insulating layers 144 are bonded. Optionally, the insulating layer 144 is a pressure-sensitive adhesive tape.

[0353] In some embodiments, the elastic modulus of the substrate layer 145 is greater than the elastic modulus of the adhesive layer 146 .

[0354] Fig. 22 A schematic partial cross-sectional view of an electrode assembly provided in some other embodiments of the present application.

[0355] Reference Fig. 22 In some embodiments, the third end surface 1222 of the second pole piece 12 is also covered with an insulating member 14. For example, the insulating member 14 covering the third end surface 1222 may have a similar structure to the insulating member 14 covering the first end surface 1122.

[0356] In some embodiments, the second pole piece 12 includes a second pole tab 124 extending from a third end surface 1222 .

[0357] In some embodiments, the electrode assembly 10 includes two insulating members 14 respectively attached to the two third end surfaces 1222 .

[0358] Exemplarily, for the insulating member 14 attached to the third end surface 1222 of the second electrode tab 124 , the total size of the insulating member 14 along the first direction Z is 5 mm, and the size of the overlapping region of the insulating member 14 and the second active material layer 123 along the first direction Z is 0.5 mm.

[0359] For the insulating member 14 attached to the third end surface 1222 without the second electrode tab 124 , the total size of the insulating member 14 along the first direction Z is 2 mm, and the size of the overlapping region of the insulating member 14 and the second active material layer 123 along the first direction Z is 0.5 mm.

[0360] Fig.23 A schematic top view of an electrode assembly provided in some other embodiments of the present application; Fig.24 for Fig.23 Schematic diagram of the cross section along the FF direction.

[0361] Reference Fig.23 and Fig.24 In some embodiments, the electrode assembly 10 further includes a separator 13, and the separator 13 is used to separate the first electrode sheet 11 from the second electrode sheet 12. In the first direction Z, one end of the second insulating portion 142 away from the first insulating portion 141 exceeds the separator 13.

[0362] The second insulating portion 142 protrudes from the isolation member 13. When the first pole ear 114 is bent, the second insulating portion 142 can limit the first pole ear 114, reduce the risk of the first pole ear 114 squeezing the isolation member 13, alleviate the wrinkles of the isolation member 13, reduce the risk of the isolation member 13 shrinking inward, and improve reliability.

[0363] In some embodiments, one end of the first current collecting body 112 along the first direction Z exceeds the second pole piece body 121 .

[0364] Fig.25 A schematic cross-sectional view of a first pole piece and an insulating member of an electrode assembly provided in some further embodiments of the present application.

[0365] Reference Fig.25 In some embodiments, the first insulating portion 141 covers part of the main body region 1131. The first insulating portion 141 is connected to the main body region 1131 and the thinning region 1132 at the same time, which can increase the connection area between the insulating member 14 and the first pole piece body 111 and reduce the risk of the insulating member 14 falling off.

[0366] Fig.26 Schematic diagram of electrode assembly provided in some embodiments of the present application. Fig.26 In the figure, the first pole piece body 111 is shown by a dotted line.

[0367] Reference Fig.26 In some embodiments, the first pole piece body 111 is in the shape of a plate. In the second direction X, both ends of the insulating member 14 do not exceed the isolation member 13. The second direction X is perpendicular to the first direction Z and the thickness direction Y.

[0368] Optionally, the second direction X may be the width direction of the first pole piece body 111 , and the first direction Z may be the length direction of the first pole piece body 111 .

[0369] Optionally, the electrode assembly 10 is a laminated structure. The electrode assembly 10 includes a plurality of first pole pieces 11, which are stacked. An insulating member 14 is disposed on each first pole piece 11.

[0370] The second pole piece 12 may be one or more. For example, the second pole piece 12 is folded to form a plurality of stacked folded segments, and a first pole piece 11 is sandwiched between adjacent folded segments.

[0371] The isolation member 13 can restrain the insulating member 14 , maintain the fit between the insulating member 14 and the first pole piece body 111 , and reduce the risk of the insulating member 14 falling off the first pole piece body 111 .

[0372] Fig. 27 Schematic diagram of the first pole piece and insulating member of the electrode assembly in the unfolded state provided in some other embodiments of the present application.

[0373] Reference Fig. 27 In some embodiments, the second insulating portion 142 is only disposed outside the non-tab lead-out region 1122 b along the first direction Z. The embodiment of the present application can reduce the amount of the insulating member 14 used.

[0374] Exemplarily, there are a plurality of second insulating portions 142 , and the plurality of second insulating portions 142 are arranged at intervals, and each second insulating portion 142 covers a non-tab lead-out area 1122 b .

[0375] According to some embodiments of the present application, the present application further provides a battery cell 6 , which includes a housing 20 and an electrode assembly 10 according to any of the above embodiments, wherein the electrode assembly 10 is accommodated in the housing 20 .

[0376] According to some embodiments of the present application, the present application also provides a battery, comprising a plurality of battery cells according to any one of the above embodiments.

[0377] According to some embodiments of the present application, the present application further provides an electric device, comprising a battery cell of any of the above embodiments, the battery cell is used to provide electric energy for the electric device. The electric device can be any of the above equipment or systems using the battery cell.

[0378] According to some embodiments of the present application, referring to Figures 4 to 14 The present embodiment provides an electrode assembly 10, including a first pole piece 11, a second pole piece 12, a separator 13 and an insulating member 14. The first pole piece 11 and the second pole piece 12 have opposite polarities, and the first pole piece 11, the second pole piece 12 and the separator 13 are wound along a winding direction V to form a winding structure.

[0379] The first pole piece 11 includes a first pole piece body 111 and a first pole ear 114. The first pole piece body 111 includes a first current collector 112 and a first active material layer 113. The first current collector 112 includes two first surfaces 1121, two first end surfaces 1122 and two second end surfaces 1123. The two first surfaces 1121 are arranged opposite to each other along the thickness direction Y of the first pole piece body 111. The two first end surfaces 1122 are respectively located at the two ends of the first current collector 112 along the first direction Z. The two second surfaces 1221 are respectively located at the two ends of the first current collector 112 along the winding direction V. The first direction Z is perpendicular to the winding direction V, and the first direction Z is perpendicular to the thickness direction Y. Each first end surface 1122 connects the two first surfaces 1121, and each second end surface 1123 connects the two first surfaces 1121.

[0380] The first surface 1121 includes a coating area 1121a and an uncoated area 1121b arranged along the first direction Z. The first active material layer 113 is disposed in the coating area 1121a, and the uncoated area 1121b is not provided with the first active material layer 113. One end of the uncoated area 1121b away from the coating area 1121a is connected to one first end surface 1122, and one end of the coating area 1121a away from the uncoated area 1121b is connected to the other first end surface 1122.

[0381] The plurality of first electrode tabs 114 extend from the same first end surface 1122 and are connected to the uncoated region 1121 b , and the plurality of first electrode tabs 114 are spaced apart along the winding direction V. The plurality of first electrode tabs 114 are integrally formed with the first current collecting body 112 .

[0382] An insulating member 14 is used to cover the first end face 1122 leading out the first electrode tab 114. Specifically, an insulating member 14 is connected to the first active material layer 113 and covers the uncoated area 1121b, the first end face 1122 and the end of the second end face 1123 close to the first end face 1122. The first electrode tab 114 passes through the insulating member 14.

[0383] Another insulating member 14 is used to cover the first end surface 1122 where the first electrode tab 114 is not led out. Specifically, another insulating member 14 is connected to the first active material layer 113 and covers the first end surface 1122 and the end of the second end surface 1123 close to the first end surface 1122.

[0384] The insulating member 14 includes two insulating layers 144, which are attached to the first pole piece 11 from both sides to form the insulating member 14. The insulating layer 144 may be a hot melt adhesive film or a pressure sensitive adhesive tape.

[0385] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0386] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, but these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An electrode assembly, characterized in that: comprising a first pole piece and a second pole piece having opposite polarities; The first pole piece includes a first pole piece body, the first pole piece body includes a first current collecting body and a first active material layer, the first current collecting body includes two first surfaces arranged opposite to each other along its thickness direction and a first end surface connecting the two first surfaces, and the first active material layer is arranged on the first surface; The electrode assembly further includes an insulating member connected to the first pole piece body, and at least a portion of the insulating member is disposed outside the first end surface along a first direction, wherein the first direction is perpendicular to the thickness direction.

2. The electrode assembly according to claim 1, characterized in that: The insulating member comprises two first insulating parts and a second insulating part; The two first insulating portions are respectively located at two sides of the first pole piece body along the thickness direction and connected to the first pole piece body; The second insulating portion connects the two first insulating portions and is disposed on the outer side of the first end surface along the first direction.

3. The electrode assembly according to claim 2, characterized in that: The second insulating portion covers at least a portion of the first end surface.

4. The electrode assembly according to claim 2 or 3, characterized in that: The first pole piece also includes a first pole tab connected to the first current collecting body, the first end surface includes a pole tab lead-out area and a non-pole tab lead-out area, the first pole tab is only led out from the pole tab lead-out area, and protrudes out of the second insulating portion along the first direction away from the first current collecting body.

5. The electrode assembly according to claim 4, characterized in that: The second insulating portion covers at least a portion of the non-tab lead-out region.

6. The electrode assembly according to claim 5, characterized in that: The second insulating portion is only disposed on the outer side of the non-tab lead-out region along the first direction.

7. The electrode assembly according to claim 5, characterized in that: The second insulating portion includes a first extension portion and a second extension portion, the first extension portion is arranged outside the non-tab lead-out area along the first direction, the second extension portion is arranged outside the tab lead-out area along the first direction and covers at least part of the tab along the thickness direction.

8. The electrode assembly according to claim 7, characterized in that: The first extension portion covers the non-tab lead-out area along the first direction.

9. The electrode assembly according to claim 8, characterized in that: A dimension of the first extension portion along the first direction is equal to a dimension of the second extension portion along the first direction.

10. The electrode assembly according to claim 8, characterized in that: The first extension portion is provided with a first part and a second part, the second part is connected to the second extension portion, the size of the second part along the first direction is equal to the size of the second extension portion along the first direction, the first part is configured to be formed by setting a recess on the second insulating portion, and the size of the first part along the first direction is smaller than the size of the second extension portion along the first direction.

11. The electrode assembly according to claim 7, characterized in that: In the first direction, a size of a root region of the first electrode tab covered by the second extension portion is greater than or equal to 0.2 times the size of the first electrode tab and less than or equal to 0.6 times the size of the first electrode tab.

12. The electrode assembly according to claim 2, characterized in that: The first insulating portion is connected to the first active material layer.

13. The electrode assembly according to claim 12, characterized in that: At least a partial region of the first insulating portion overlaps with the first active material layer in the thickness direction and is connected to the first active material layer.

14. The electrode assembly according to claim 12 or 13, characterized in that: The first active material layer comprises a main body region arranged along the first direction and a thinning region connected to the main body region, wherein the thinning region is located on one side of the main body region close to the first end surface along the first direction, and the thickness of at least part of the thinning region is smaller than the thickness of the main body region; The first insulating portion covers at least a portion of the thinned region along the thickness direction.

15. The electrode assembly according to claim 14, characterized in that: In a direction from the first current collecting body to the first active material layer, the first insulating portion does not extend beyond a surface of the main region away from the first current collecting body.

16. The electrode assembly according to claim 14, characterized in that In the first direction, the first insulating portion is spaced apart from the main region.

17. The electrode assembly according to claim 14, characterized in that The first insulating portion covers a portion of the body region.

18. The electrode assembly according to claim 14, characterized in that A thickness t1 of the thinned region at an end away from the main region is less than or equal to 0.5 times a thickness t2 of the main region.

19. The electrode assembly according to claim 2, characterized in that: The first surface includes a coated area and an uncoated area arranged along the first direction, one end of the uncoated area is connected to the first end surface, and the other end is connected to the coated area, the coated area is coated with the first active material layer, and the uncoated area is not coated with the first active material layer; The first insulating portion is connected to the uncoated region.

20. The electrode assembly according to claim 19, characterized in that The first insulating portion completely covers the uncoated area.

21. The electrode assembly according to claim 19, characterized in that In the first direction, a size of a region where the insulating member covers the uncoated area is greater than or equal to 1 mm.

22. The electrode assembly according to claim 19, characterized in that The first pole piece further includes a first pole lug, which extends outward from the first end surface along the first direction and passes through the second insulating portion.

23. The electrode assembly according to claim 2, characterized in that The insulating member comprises two independently formed insulating layers, wherein the insulating layer comprises an insulating body and a connecting portion connected to the insulating body; in the thickness direction, the insulating body overlaps with the first pole piece body, and the connecting portion does not overlap with the first pole piece body; The insulating bodies of the two insulating layers respectively form two first insulating parts; and the connecting parts of the two insulating layers are stacked and connected to form the second insulating part.

24. The electrode assembly according to claim 23, characterized in that The thickness of the insulating layer is 7 μm-30 μm.

25. The electrode assembly according to claim 23, characterized in that An insulation value of a difference between a thickness of the insulating layer and a thickness of the first current collecting body is not greater than 10 μm, and optionally, not greater than 5 μm.

26. The electrode assembly according to claim 23, characterized in that The first pole piece further includes a first pole lug connected to the first current collecting body, the first end surface includes a pole lug lead-out area and a non-pole lug lead-out area, the first pole lug only extends from the pole lug lead-out area and protrudes from the second insulating portion in a direction away from the first current collecting body; The two connecting portions are directly connected to the non-overlapping portion of the first tab to form a first extension portion, and the first extension portion covers the non-tab lead-out area along the first direction; The overlapping parts of the two connecting portions and the first electrode tab form a second extending portion, and cover at least a portion of the first electrode tab along the thickness direction.

27. The electrode assembly according to claim 26, characterized in that A dimension of the first extension portion along the first direction is equal to a dimension of the second extension portion along the first direction.

28. The electrode assembly according to claim 2, characterized in that The insulating member is an integrally formed structure.

29. The electrode assembly according to claim 2, characterized in that The first current collecting body further includes two second end surfaces, the two second end surfaces are respectively arranged at two ends of the first end surface, and each second end surface is connected to two first surfaces; The insulating member further includes a third insulating portion connected to the first insulating portion and the second insulating portion and covering a portion of the second end surface.

30. The electrode assembly according to claim 2, characterized in that The first current collecting body comprises two first end faces arranged opposite to each other along a first direction, and the first direction is perpendicular to the thickness direction of the first pole piece body; The electrode assembly includes two insulating members, and the two insulating members are respectively arranged on the outer sides of the two first end surfaces.

31. The electrode assembly according to claim 2, characterized in that The electrode assembly further includes a separator, which is used to separate the first pole piece from the second pole piece; In the first direction, one end of the second insulating portion away from the first insulating portion exceeds the isolation member.

32. The electrode assembly according to claim 2, characterized in that The electrode assembly further includes a separator, which is used to separate the first pole piece from the second pole piece; In the first direction, an end of the second insulating portion away from the first insulating portion does not exceed the isolation member.

33. The electrode assembly according to claim 1, characterized in that The second pole piece comprises a second pole piece body, and the second pole piece body is stacked with the first pole piece body; The second pole piece body comprises a second current collecting body and a second active material layer, the second current collecting body comprises two second surfaces arranged opposite to each other and a third end surface connecting the two second surfaces, and the second active material layer is arranged on the second surface; The first end surface is located at one end of the first current collecting body along the first direction, and the third end surface is located at one end of the second current collecting body along the first direction; In the thickness direction, the insulating member separates the third end surface from the first pole piece.

34. The electrode assembly according to claim 33, characterized in that The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece; In the first direction, both ends of the second active material layer extend beyond the first pole piece body.

35. The electrode assembly according to claim 1, characterized in that The melting point of the insulating member is 95°C-150°C.

36. The electrode assembly according to claim 1, characterized in that The insulating member includes a colloid, and the colloid includes at least one of ethylene and copolymers thereof, polyolefin, polyester, polyurethane, polyamide, styrene and block copolymers thereof.

37. The electrode assembly according to claim 1, characterized in that The insulating member includes a substrate layer and an adhesive layer, and the substrate layer is connected to the first pole piece body through the adhesive layer.

38. The electrode assembly according to claim 37, characterized in that The substrate layer comprises at least one of polyethylene terephthalate, polypropylene, polyethylene and block copolymers thereof; The adhesive layer includes at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene or butyl rubber.

39. The electrode assembly according to claim 1, characterized in that The elastic modulus of the insulating component is 500Mpa-3000Mpa. Optionally, the elastic modulus of the insulating component is 770Mpa-1320Mpa.

40. The electrode assembly according to claim 1, characterized in that The tensile strength of the insulating member is 949kgf / cm 2 -1363kgf / cm 2 .

41. The electrode assembly according to claim 1, characterized in that The insulating member is connected to the first active material layer; The peeling strength between the insulating member and the first active material layer is higher than the peeling strength between the first active material layer and the first surface.

42. The electrode assembly according to claim 1, characterized in that The electrode assembly further includes a separator, which is used to separate the first pole piece from the second pole piece; The first pole piece, the insulating member and the second pole piece are wound, and in the winding direction of the first pole piece, the two ends of the insulating member do not exceed the insulating member; or, the first pole piece body is flat, and in the second direction, the two ends of the insulating member do not exceed the insulating member, and the second direction is perpendicular to the first direction and the thickness direction.

43. A battery cell, characterized in that: include: shell; The electrode assembly according to any one of claims 1 to 42 is accommodated in the shell.

44. A battery, characterized in that: Comprising a plurality of battery cells according to claim 43.

45. An electrical device, characterized in that: Comprising a battery according to claim 44, the battery is used to provide electrical energy.

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