Electrode assembly, battery cell, battery and electric device

Abstract

The invention 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

Electrode assembly, battery cell, battery and electrical device Technical Field

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

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

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

[0004] Summary of the Invention

[0005] The present application provides an electrode assembly, a battery cell, a battery, and an electrical device, which can improve reliability.

[0006] In a first aspect, embodiments of the present application provide an electrode assembly comprising a first electrode sheet and a second electrode sheet of opposite polarity. The first electrode sheet comprises a first electrode sheet body, which comprises a first current collector and a first active material layer. The first current collector comprises two first surfaces disposed opposite each other along its thickness direction and a first end surface connecting the two first surfaces. The first active material layer is disposed on the first surface. The electrode assembly further comprises an insulating member connected to the first electrode sheet body, with at least a portion of the insulating member disposed outside the first end surface along a first direction perpendicular to the thickness direction.

[0007] 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.

[0008] In one or more of the above optional embodiments, the insulating member includes two first insulating portions and a second insulating portion. The two first insulating portions are located on opposite 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 located outside the first end surface along the first direction.

[0009] By providing two first insulating portions, the connection area between the insulating member and the first pole piece body can be increased, reducing the risk of the insulating member falling off. The second insulating portion can separate burrs on the first end face from the second pole piece, thereby reducing the risk of short circuits.

[0010] 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.

[0011] In one or more of the above optional embodiments, the first pole piece further includes a first tab connected to the first current collector, the first end surface includes a tab lead-out region and a non-tab lead-out region, the first tab extends only from the tab lead-out region and protrudes from the second insulating portion along a first direction away from the first current collector. The first tab protrudes from the second insulating portion to facilitate connection with other conductive structures and reduce the risk of interference between the second insulating portion and the conductive structures.

[0012] 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 burrs on the non-tab lead-out region from the second pole piece, thereby reducing the risk of short circuit.

[0013] 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 amount of insulating member used.

[0014] 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-tab lead-out area along the first direction, and the second extension portion is arranged on the outside of the tab lead-out area along the first direction and covers at least part of the tab along the thickness direction.

[0015] The first extension can separate burrs on the non-tab lead-out area from the second pole piece, thereby reducing the risk of short circuits. The second extension can support the root of the first tab near the tab lead-out area, reducing the risk of the first tab being inserted upside down between the first and second pole pieces when bent, thereby reducing the risk of short circuits and improving reliability.

[0016] 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.

[0017] 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 to facilitate molding.

[0018] In one or more of the above optional embodiments, the first extension portion includes a first portion and a second portion, the second portion being connected to the second extension portion, the second portion having a dimension along the first direction equal to the dimension of the second extension portion along the first direction, and the first portion being configured to be formed by providing a recess on the second insulating portion, the first portion having a dimension along the first direction smaller than the dimension of the second extension portion along the first direction. Providing the recess can reduce the dimension of the first portion along the first direction, thereby reducing the amount of insulating components used and increasing the energy density of the battery cell.

[0019] In one or more of the above optional embodiments, in the first direction, the size of the root area of ​​the first tab covered by the second extension is greater than or equal to 0.2 times the size of the first tab. The second extension can provide effective support for the first tab, reduce the risk of the first tab being inserted upside down between the first and second pole pieces, and improve reliability.

[0020] 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 less than or equal to 0.6 times the size of the first pole tab, so as to reduce the volume and weight of the insulating member and improve the energy density.

[0021] 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.

[0022] 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 electrode body.

[0023] In one or more of the above optional embodiments, the first active material layer includes a main body region arranged along the first direction and a thinned region connected to the main body region, the thinned region is located on a side of the main body region close to the first end face along the first direction, and the thickness of at least a portion of the thinned region is less 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.

[0024] The thinning region reduces pressure on the edge of the first active material layer during rolling of the first electrode sheet, minimizing the risk of cracking the first current collector. Utilizing the space along one side of the thinning region in the thickness direction to arrange the first insulating portion improves space utilization.

[0025] In one or more of the above optional embodiments, along the direction of the first current collecting body pointing 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 additional 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.

[0026] 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.

[0027] In one or more of the above optional embodiments, the first insulating portion covers part of the main body region. The first insulating portion is connected to both the main body region and the thinned region, 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.

[0028] In one or more of the above optional embodiments, the thickness t1 of the thinned region at the end away from the main body region is less than or equal to 0.5 times the thickness t2 of the main body region. The thinned region at the end away from the main body region has a smaller thickness, which can reduce the area covered by the second insulating portion, reduce the force at the connection between the first insulating portion and the second insulating portion, and reduce the risk of cracking or falling off of the insulating member.

[0029] In one or more of the above optional embodiments, 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.

[0030] By providing an uncoated area, the connection area between the first current collector and the insulating member can be increased, reducing the risk of the insulating member falling off and improving reliability. The first end surface and the first active material layer are spaced apart along the first direction. This reduces the risk of cutting the first active material layer during cutting of the first electrode sheet, thereby reducing waste of active material.

[0031] 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.

[0032] In one or more optional embodiments above, 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.

[0033] In one or more optional embodiments above, the first pole piece further includes a first pole tab, which extends outward from the first end surface along the first direction and passes through the second insulating portion.

[0034] In one or more of the above optional embodiments, the insulating member includes two independently formed insulating layers, each of which 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.

[0035] 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.

[0036] In one or more of the above optional embodiments, the thickness of the insulating layer is 7 μm to 30 μm. Limiting the thickness of the insulating layer to greater than or equal to 7 μm can reduce the risk of puncture of the insulating layer by burrs, thereby improving reliability. Limiting the thickness of the insulating layer to less than or equal to 30 μm can reduce the space and weight occupied by the insulating layer, thereby reducing the loss of energy density of the battery cell.

[0037] 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.

[0038] 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.

[0039] In one or more optional embodiments above, the first end face includes a tab lead-out area and a non-tab lead-out area, and the first tab extends only from the tab 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 and form a first extension portion, and the first extension portion covers the non-tab lead-out area along the first direction. The portion where the two connecting portions overlap with the first tab forms a second extension portion, and covers at least a portion of the first tab along the thickness direction. The first extension portion can cover the non-tab lead-out area, thereby shielding burrs on the non-tab lead-out area and reducing the risk of short circuit.

[0040] 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.

[0041] 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.

[0042] In one or more of the above optional embodiments, the first current collector further includes two second end surfaces, one located at each end of the first end surface, each second end surface connected to the two first surfaces. The insulating member further includes a third insulating portion, which is connected to the first and second insulating portions and covers a portion of the second end surface. The third insulating portion can cover burrs on the second end surface, thereby reducing the risk of short circuits and improving reliability. The provision of the third insulating portion can also reduce the risk of the first end surface being exposed due to assembly errors.

[0043] In one or more of the above optional embodiments, the first current collector includes two first end surfaces arranged opposite each other along a first direction, the first direction being perpendicular to the thickness of the first electrode body. The electrode assembly includes two insulating members, each disposed outside the two first end surfaces. The two insulating members can isolate burrs on the two first end surfaces from the second electrode, thereby further reducing the risk of short circuits.

[0044] In one or more optional embodiments above, the electrode assembly further comprises a separator, the separator being used to separate the first electrode piece from the second electrode piece. In the first direction, one end of the second insulating portion away from the first insulating portion exceeds the separator.

[0045] The second insulating portion protrudes from the isolating member. When the first tab is bent, the second insulating portion can restrict the first tab, reduce the risk of the first tab squeezing the isolating member, alleviate wrinkles on the isolating member, reduce the risk of the isolating member shrinking inward, and improve reliability.

[0046] In one or more of the above optional embodiments, the electrode assembly further includes a separator for separating the first electrode piece from the second electrode piece. In the first direction, an end of the second insulating portion distal from the first insulating portion does not extend beyond the separator, thereby reducing the amount of the second insulating portion, reducing the weight and space occupied by the second insulating portion, and improving energy density.

[0047] In one or more of the above optional embodiments, the second pole piece includes a second pole piece body, which 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. The second current collecting body includes two second surfaces arranged opposite to each other and a third end face connecting the two second surfaces. The second active material layer is provided 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.

[0048] 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.

[0049] In one or more optional embodiments above, the first electrode is a positive electrode, and the second electrode is a negative electrode. In the first direction, both ends of the second active material layer extend beyond the main body of the first electrode. 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 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.

[0050] In one or more of the above optional embodiments, the insulating member has a melting point of 95°C to 150°C. During the charge and discharge process of the battery cell, the first current collector generates heat. Having a higher melting point for the insulating member reduces the risk of thermal softening and detachment, thereby improving reliability.

[0051] In one or more of the above optional embodiments, 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 high bonding strength and is not easily detached from the first pole piece body.

[0052] In one or more of the above optional embodiments, the insulating member includes a substrate layer and an adhesive layer, wherein the substrate layer is connected to the first pole piece body via the adhesive layer. The substrate layer can enhance the strength of the insulating member and reduce deformation of the insulating member during attachment. The adhesive layer can adhere the substrate layer to the first pole piece body, reducing the risk of the substrate layer falling off the first pole piece body.

[0053] In one or more optional embodiments above, the substrate layer comprises at least one of polyethylene terephthalate, polypropylene, polyethylene, and block copolymers thereof, and the adhesive layer comprises at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene, or butyl rubber.

[0054] In one or more of the above optional embodiments, the elastic modulus of the insulating member is 500 MPa-3000 MPa, and optionally, the elastic modulus of the insulating member is 770 MPa-1320 MPa. The insulating member has a high elastic modulus, which can provide support for the first electrode tab, reduce the risk of the root of the first electrode tab being inserted between the first and second electrode pieces, and improve reliability.

[0055] 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 tab. Accordingly, the insulating member can effectively limit the deformation of the first pole tab, reduce the risk of the root of the first pole tab being inserted inverted between the first pole piece and the second pole piece, and improve reliability.

[0056] In one or more of the above optional embodiments, 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 higher peel strength between the insulating member and the first active material layer reduces the risk of the insulating member falling off and improves reliability.

[0057] In one or more of the above optional embodiments, the electrode assembly further includes a separator, which is used to separate the first electrode sheet from the second electrode sheet. The first electrode sheet, the separator, and the second electrode sheet are wound together, and in the winding direction of the first electrode sheet, both ends of the insulating member do not extend beyond the separator. The separator can restrain the insulating member, maintain the fit between the insulating member and the main body of the first electrode sheet, and reduce the risk of the insulating member falling off the main body of the first electrode sheet.

[0058] In one or more of the above optional embodiments, the electrode assembly further includes a separator for separating the first electrode piece from the second electrode piece. The first electrode piece body is flat, and both ends of the insulating member do not extend beyond the separator in the second direction, and the second direction is perpendicular to the first direction and the thickness direction. The separator can restrain the insulating member, maintain the fit between the insulating member and the first electrode piece body, and reduce the risk of the insulating member falling off the first electrode piece body.

[0059] 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 embodiment of the first aspect, wherein the electrode assembly is accommodated in the housing.

[0060] In a third aspect, an embodiment of the present application provides a battery comprising a plurality of battery cells provided according to any embodiment of the second aspect.

[0061] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising a battery provided according to any embodiment of the third aspect, wherein the battery is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. 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 creative work.

[0063] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0064] FIG2 is a schematic diagram of an explosion of a battery provided in some embodiments of the present application;

[0065] FIG3 is a schematic diagram of an explosion of a battery cell provided in some embodiments of the present application;

[0066] FIG4 is a schematic top view of an electrode assembly provided in some embodiments of the present application;

[0067] FIG5 is a partial cross-sectional schematic diagram taken along the AA direction in FIG4 ;

[0068] FIG6 is a schematic diagram of a first electrode piece of an electrode assembly in a flattened state according to some embodiments of the present application;

[0069] FIG7 is a schematic cross-sectional view taken along the EE direction of FIG6;

[0070] FIG8 is a schematic diagram of FIG6 at another angle;

[0071] FIG9 is a schematic diagram of the first pole piece shown in FIG6 after being connected to the insulating member;

[0072] FIG10 is a schematic diagram of an insulating member of an electrode assembly provided in some embodiments of the present application;

[0073] FIG11 is a schematic cross-sectional view taken along the BB direction of FIG9 ;

[0074] FIG12 is a cross-sectional view taken along the CC direction of FIG9;

[0075] FIG13 is a schematic diagram of the first pole piece and the insulating member shown in FIG9 at another angle;

[0076] FIG14 is a schematic diagram of an insulating layer of an electrode assembly provided by some embodiments of the present application in a flattened state;

[0077] FIG15 is a schematic diagram of a first electrode piece of an electrode assembly in an unfolded state provided by some other embodiments of the present application;

[0078] FIG16 is a schematic diagram of the first pole piece shown in FIG15 after being connected to the insulating member;

[0079] FIG17 is a schematic cross-sectional view taken along the DD direction of FIG16;

[0080] FIG18 is a schematic diagram of an insulating member provided by some embodiments of the present application before being assembled to a first pole piece;

[0081] FIG19 is a schematic diagram of a first electrode piece and an insulating member of an electrode assembly in an unfolded state provided by yet other embodiments of the present application;

[0082] FIG20 is an enlarged schematic diagram of the circle frame of FIG19;

[0083] FIG21 is a schematic structural diagram of an insulating member of an electrode assembly provided in some embodiments of the present application;

[0084] FIG22 is a partial cross-sectional schematic diagram of an electrode assembly provided in some other embodiments of the present application;

[0085] FIG23 is a schematic top view of an electrode assembly provided in some other embodiments of the present application;

[0086] FIG24 is a schematic cross-sectional view taken along the FF direction of FIG23;

[0087] FIG25 is a schematic cross-sectional view of a first electrode piece and an insulating member of an electrode assembly provided in still other embodiments of the present application;

[0088] FIG26 is a schematic diagram of an electrode assembly provided in some other embodiments of the present application;

[0089] Figure 27 is a schematic diagram of the first pole piece and insulating member of the electrode assembly provided in some other embodiments of the present application in the unfolded state.

[0090] The accompanying drawings are numbered as follows: 1. vehicle; 2. battery; 3. controller; 4. motor; 5. housing; 5a. first housing portion; 5b. second housing portion; 5c. accommodation space; 6. battery cell; 10. electrode assembly; 20. housing; 21. casing; 22. end cap; 30. electrode terminal; 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. tab lead-out area; 1122b. non-tab lead-out area; 1123. second end surface; 113. first active material layer; 1131. main body area; 1132. thinning area; 114. first tab; 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 tab; 13. Isolator; 14. Insulator; 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. Recess; V, winding direction; L, length direction; X, second direction; Y, thickness direction; Z, first direction. DETAILED DESCRIPTION

[0091] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0092] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" 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-secondary relationship.

[0093] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0094] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0095] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0096] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0097] The term "plurality" used in this application refers to two or more (including two).

[0098] 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.

[0099] 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-hydrogen battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0100] As an example, the battery cell can 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 special limitation in this application.

[0101] 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.

[0102] 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.

[0103] 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 housed in the case.

[0104] 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.

[0105] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0106] A battery cell generally consists of an electrode assembly and a housing, with the electrode assembly housed within 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 released back and forth between the positive and negative electrodes. A separator is placed between the positive and negative electrodes to reduce the risk of short circuits while allowing active ions to pass through.

[0107] The housing is used to encapsulate the electrode assembly and electrolyte components. The housing 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.

[0108] 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.

[0109] During the preparation of electrodes (positive or negative), cutting (e.g., electrode slitting or tab die-cutting) is typically required to achieve the desired size and shape. However, after cutting, burrs are prone to form on the current collector at the cutting locations. During the charge and discharge process of the battery cell, these burrs may puncture the separator and connect the positive and negative electrodes, causing a short circuit risk and affecting the reliability of the battery cell.

[0110] In view of this, an embodiment of the present application provides a technical solution, which provides an insulating member on the pole piece to block the burrs on the end face of the current collector, thereby reducing the risk of the burrs conducting the positive and negative electrodes and improving the reliability of the battery cell.

[0111] The electrode assembly described in the embodiments of the present application is applicable to battery cells, batteries, and electrical devices using batteries.

[0112] The battery disclosed in the embodiments of the present application can be used in electrical devices that use the battery as a power source or 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 computer, 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 fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like, and the spacecraft can include airplanes, rockets, space shuttles, and spacecraft, and the like.

[0113] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0114] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0115] As shown in FIG1 , a battery 2 is provided inside the vehicle 1. The battery 2 may be provided 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 serve as an operating power source for the vehicle 1.

[0116] The vehicle 1 may further include a controller 3 and a motor 4 . 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 the vehicle 1 during startup, navigation, and driving.

[0117] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also serve as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0118] FIG2 is an exploded view of a battery according to some embodiments of the present application. As shown in FIG2 , the battery 2 includes a housing 5 and a battery cell 6 , wherein the battery cell 6 is accommodated in the housing 5 .

[0119] The housing 5 is used to accommodate the battery cells 6 and can have various structures. In some embodiments, the housing 5 can include a first housing portion 5a and a second housing portion 5b. The first housing portion 5a and the second housing portion 5b overlap each other and together define a storage space 5c for accommodating the battery cells. The second housing portion 5b can be a hollow structure with one end open. The first housing portion 5a is a plate-like structure, and the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. The first housing portion 5a and the second housing portion 5b can also be hollow structures with one end open. The open side of the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0120] In order to improve the sealing performance after the first box body 5a and the second box body 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 5a and the second box body 5b.

[0121] 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 body.

[0122] In the battery 2, there can be one or more battery cells 6. If there are multiple battery cells 6, the multiple battery cells 6 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections within the multiple battery cells 6. The multiple battery cells 6 can be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 6 is housed within the housing 5. Alternatively, multiple battery cells can be first connected in series, in parallel, or in a hybrid connection to form a battery module, and then the multiple battery modules can be connected in series, in parallel, or in a hybrid connection to form a single unit and housed within the housing 5.

[0123] Illustratively, a battery cell may be the smallest unit constituting a battery.

[0124] FIG3 is a schematic diagram of an explosion of a battery cell provided in some embodiments of the present application.

[0125] As shown in FIG. 3 , in some embodiments, the battery cell 6 includes a housing 20 and an electrode assembly 10 housed in the housing 20 .

[0126] 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 (e.g., lithium ions) are intercalated and released between the positive and negative electrodes. Optionally, the electrode assembly 10 also includes a separator disposed between the positive and negative electrodes. The separator can reduce the risk of short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] The housing 21 and the end cap 22 may be separate components. For example, an opening may be provided on the housing 21 , and the end cap 22 may be placed over the opening to form an internal cavity of the battery cell 6 .

[0131] The housing 21 can have various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 10. The housing 21 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum-plastic film, steel-plastic film, etc.

[0132] The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. The material of the end cap 22 can be the same as or different from the material of the housing 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (e.g., copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.). In this way, the end cap 22 is less likely to deform when subjected to compression or collision, thereby providing the battery cell 6 with higher structural strength and improved reliability.

[0133] The end cover 22 is connected to the housing 21 by welding, bonding, clamping or other methods.

[0134] The housing 21 may be open at one end or at both ends. In some examples, the housing 21 may be open at one end, with one end cap 22 provided to cover the housing 21. In other examples, the housing 21 may be open at both ends, with two end caps 22 provided to cover the two openings of the housing 21, respectively.

[0135] 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 from the battery cell 6 .

[0136] In some embodiments, the battery cell 6 further includes an electrolyte contained in the housing 20. The electrolyte conducts ions between the positive and negative electrodes and can be in liquid, gel, or solid form.

[0137] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0138] 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.

[0139] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl 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, 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.

[0140] In some embodiments, the gel electrolyte includes a polymer as an electrolyte skeleton network and an ionic liquid-lithium salt.

[0141] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, or a composite solid electrolyte.

[0142] 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, or the like.

[0143] 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.

[0144] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0145] FIG4 is a schematic top view of an electrode assembly provided in some embodiments of the present application; FIG5 is a schematic partial cross-sectional view taken along the AA direction of FIG4 .

[0146] 4 and 5 , the electrode assembly 10 according to the embodiment of the present application includes a first electrode piece 11 and a second electrode piece 12 having opposite polarities.

[0147] Exemplarily, one of the first electrode sheet 11 and the second electrode sheet 12 is a positive electrode sheet, and the other is a negative electrode sheet.

[0148] 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.

[0149] 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 provided on either or both of the two facing surfaces of the positive electrode current collector.

[0150] As an example, the positive electrode current collector may be made of carbon, metal foil, or a composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, carbon electrode, aluminum or stainless steel with a nickel, titanium, or silver surface treatment may be used. The composite current collector may include a polymer material base layer 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.).

[0151] 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: lithium-containing phosphate, 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 the positive electrode active material layer of the battery. These positive electrode active materials can 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 / 3 Mn 1 / 3 O2 (also referred to as NCM333), LiNi 0.5 Co 0.2Mn 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 at least one of its modified compounds, etc.

[0152] 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.

[0153] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. may be used. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may 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.).

[0154] As an example, the negative electrode active material layer includes a negative electrode active material. The negative electrode active material may be 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.

[0155] 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.

[0156] In some embodiments, the electrode assembly 10 further includes a separator 13, which is used to separate the first electrode 11 from the second electrode 12. The separator 13 can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0157] In some embodiments, the separator 13 includes an isolation membrane. The isolation membrane of the present application can be any well-known porous structure isolation membrane with good chemical stability and mechanical stability.

[0158] As an example, the primary 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 positioned between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0159] 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 serves to transmit ions and isolate the positive and negative electrodes.

[0160] In some embodiments, the electrode assembly 10 is a wound structure. For example, the first electrode sheet 11 and the second electrode sheet 12 are both strip-shaped structures, and the first electrode sheet 11, the separator 13, and the second electrode sheet 12 are wound into a wound structure.

[0161] In some embodiments, the electrode assembly 10 is a laminated structure.

[0162] As an example, a plurality of first pole pieces 11 and a plurality of 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.

[0163] As an example, a plurality of first pole pieces 11 may be provided, and the second pole piece 12 may be folded to form a plurality of stacked folded segments, with one first pole piece 11 being sandwiched between adjacent folded segments.

[0164] 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.

[0165] As an example, a plurality of spacers 13 may be provided, each spacer being provided between any adjacent first pole pieces 11 or second pole pieces 12 .

[0166] As an example, the spacer 13 may be provided continuously, and may be provided between any adjacent first pole pieces 11 or second pole pieces 12 by folding or winding.

[0167] In some embodiments, the shape of the electrode assembly 10 can be cylindrical, flat, or polygonal.

[0168] Figure 6 is a schematic diagram of the first pole piece of the electrode assembly provided in some embodiments of the present application in a flattened state; Figure 7 is a schematic diagram of a cross-sectional view of Figure 6 taken along the EE direction; Figure 8 is a schematic diagram of Figure 6 at another angle; Figure 9 is a schematic diagram of the first pole piece shown in Figure 6 after being connected to the insulating member, wherein the portion of the first pole piece covered by the insulating member is shown with a dotted line; Figure 10 is a schematic diagram of an insulating member of the electrode assembly provided in some embodiments of the present application; Figure 11 is a schematic diagram of a cross-sectional view of Figure 9 taken along the BB direction; Figure 12 is a cross-sectional view of Figure 9 taken along the CC direction; Figure 13 is a schematic diagram of the first pole piece and the insulating member shown in Figure 9 at another angle; Figure 14 is a schematic diagram of the insulating layer of the electrode assembly provided in some embodiments of the present application in a flattened state, wherein the boundary between the insulating body and the connecting portion is shown with a dotted line.

[0169] 4 to 14 , an embodiment of the present application provides an electrode assembly 10 , which includes a first electrode piece 11 and a second electrode piece 12 with opposite polarities.

[0170] The first electrode 11 includes a first electrode 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.

[0171] In some examples, the first electrode sheet 11 is a positive electrode sheet, the positive electrode current collector may include a first current collecting 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 collecting body 112, and the first active material layer 113 is a negative electrode active material layer.

[0172] The first active material layer 113 may be entirely disposed on the first surface 1121. Alternatively, a portion of the first active material layer 113 may be disposed at other locations. For example, if the first electrode sheet 11 further includes a first electrode tab 114 connected to the first current collector 112, a portion of the first active material layer 113 may be disposed at the root of the first electrode tab 114 near the first current collector 112.

[0173] 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 .

[0174] Exemplarily, the first current collecting body 112 has a relatively small thickness, and the first end surface 1122 is relatively small in the thickness direction Y of the first electrode body 111. The first end surface 1122 can be approximately a line. Optionally, the thickness of the first current collecting body 112 is 2 μm to 30 μm. Optionally, the thickness of the first current collecting body 112 is 5 μm to 15 μm.

[0175] Exemplarily, at least a portion of the first end surface 1122 is formed during the cutting process of the first pole piece 11 .

[0176] 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 perpendicular to the thickness direction Y.

[0177] For example, “at least a portion 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 and the first end face 1122 overlap in the first direction Z, as long as at least a portion of the insulating member 14 protrudes from the first end face 1122 in the first direction Z.

[0178] Exemplarily, at least a portion of the first end surface 1122 overlaps with the insulating member 14 in the thickness direction.

[0179] 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.

[0180] The insulating member 14 may be directly connected to the first active material layer 113 , directly connected to the first current collecting body 112 , or directly connected to both the first active material layer 113 and the first current collecting body 112 .

[0181] 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.

[0182] There may be one or more insulating members 14 .

[0183] 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 attaching rather than bonding.

[0184] 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.

[0185] For example, 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 .

[0186] 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 provided on the outer side of the first end surface 1122 along the first direction Z.

[0187] 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 .

[0188] The shapes of the two first insulating portions 141 may be the same or different.

[0189] The first insulating portion 141 may be connected to the first active material layer 113 or the first current collecting body 112 .

[0190] The two first insulating portions 141 can increase the connection area between the insulating member 14 and the first pole piece body 111, 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.

[0191] 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.

[0192] In the first direction, the second insulating portion 142 at least partially overlaps with the first end surface 1122 to cover at least a portion of the first end surface 1122 .

[0193] 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 .

[0194] In some embodiments, the first electrode piece 11 further includes a first electrode tab 114 , and the first electrode tab 114 is connected to the first current collecting body 112 .

[0195] 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.

[0196] There may be one or more first electrode tabs 114 .

[0197] In some embodiments, the first electrode tab 114 is integrally formed with the first current collector 112. For example, the first electrode tab 114 can be formed by a die-cutting process; during the molding process of the first electrode sheet, a portion of the first electrode sheet is removed by the die-cutting process to form the protruding first electrode tab 114.

[0198] 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.

[0199] Illustratively, after the first electrode 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 electrode piece 111 , or at one end of the first current collecting body 112 along the width direction of the first electrode piece body 111 .

[0200] In some embodiments, the first current collecting body 112 has two first end surfaces 1122 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 .

[0201] 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 .

[0202] In some embodiments, the first pole piece 11 further includes a first pole tab 114 , and the first pole tab 114 extends outward from the first end surface 1122 along the first direction Z.

[0203] Illustratively, the first current collecting body 112 has two first end surfaces 1122, and all first electrode tabs 114 extend outward from the same first end surface 1122. Alternatively, there are multiple first electrode tabs 114, with some first electrode tabs 114 extending outward from one first end surface 1122 and another portion of first electrode tabs 114 extending outward from another first end surface 1122.

[0204] In some embodiments, the first tab 114 extends outward from the first end surface 1122 along the first direction Z and passes through the second insulating portion 142 .

[0205] 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.

[0206] In some embodiments, the first end surface 1122 includes a tab lead-out area 1122a and a non-tab lead-out area 1122b , and the first tab 114 extends only from the tab lead-out area 1122a and protrudes from the second insulating portion 142 along the first direction Z away from the first current collecting body 112 .

[0207] There may be one or more tab lead-out regions 1122a. For example, the number of tab lead-out regions 1122a corresponds to the number of first tabs 114. After the first tabs 114 are removed, the tab lead-out regions 1122a are exposed.

[0208] There can be one or more non-tab lead-out regions 1122b.

[0209] 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.

[0210] The first 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 structures.

[0211] In some embodiments, the second insulating portion 142 covers at least a portion of the non-tab lead-out region 1122 b . The second insulating portion 142 can separate burrs on the non-tab lead-out region 1122 b from the second pole piece, thereby reducing the risk of short circuits.

[0212] 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 in the non-tab lead-out region 1122b and reducing the risk of short circuit.

[0213] In some embodiments, the second insulating portion 142 has a channel 142 a , the first tab 114 passes through the channel 142 a , and the second insulating portion 142 completely covers the non-tab lead-out region 1122 b .

[0214] By providing the channel 142 a , the first electrode tab 114 can be avoided, thereby reducing the risk of interference between the insulating member 14 and the first electrode tab 114 .

[0215] 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 outside of the non-tab lead-out area 1122b along the first direction Z, and the second extension portion 1422 is arranged on the outside of the tab lead-out area 1122a along the first direction Z, and covers at least part of the first tab along the thickness direction Y.

[0216] For example, 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 .

[0217] 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.

[0218] The second extension portion 1422 can support the root of the first tab 114 near the tab lead-out region 1122a, reducing the risk of the first 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.

[0219] For example, in the battery cell 6, in order to save the space occupied by the first pole tab 114, the first pole tab 114 can be bent; during the bending process, the root of the first pole tab 114 may be deformed and inserted upside down 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 tab 114 close to the pole tab lead-out area 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 bending.

[0220] 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.

[0221] 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.

[0222] The second insulating portion 142 is uniformly widthwise and is easy to shape.

[0223] In some embodiments, D1 is 2 mm-10 mm.

[0224] Optionally, D1 is 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0225] In this embodiment of the present application, D1 is limited to greater than or equal to 2 mm to provide effective support for the first electrode tab 114, reduce the risk of the first electrode tab 114 being inserted upside down between the first electrode sheet 11 and the second electrode sheet 12, and improve reliability. In this embodiment of the present application, D1 is limited to less than or equal to 10 mm to reduce the volume and weight of the insulating member 14 and improve energy density.

[0226] In some embodiments, in the first direction Z, a 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.

[0227] W3 / W4 is limited to greater than or equal to 0.2 to provide effective support for the first electrode tab 114, reduce the risk of the first electrode tab 114 being inserted upside down between the first electrode sheet 11 and the second electrode sheet 12, and improve reliability. In the embodiment of the present application, W3 / W4 is limited to less than or equal to 0.6 to reduce the volume and weight of the insulating member 14 and improve energy density.

[0228] In some embodiments, D1 is equal to W3.

[0229] 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.

[0230] 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 the winding direction V of the first pole piece 11 .

[0231] In some embodiments, the first extension portion 1421 is connected to the second extension portion 1422 .

[0232] In some embodiments, the second insulating portion 142 connects adjacent first tabs 114. When the first tabs 114 are bent, the roots of the adjacent first tabs 114 can be limited by the second insulating portion 142 to limit deformation of each other, thereby reducing the risk of the first tabs 114 being inserted upside down between the first and second tabs 11 and 12, and improving reliability.

[0233] In some embodiments, the second insulating portion 142 connects the plurality of first tabs 114 .

[0234] 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 electrode body 111 and reduce the risk of the insulating member 14 falling off.

[0235] The first insulating portion 141 and the first active material layer 113 may or may not overlap in the thickness direction Y.

[0236] 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 .

[0237] 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 .

[0238] In some embodiments, the width of the overlapping region between the first insulating portion 141 and the first active material layer 113 is W1 , and W1 is 0.1 mm-1 mm.

[0239] 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.

[0240] Limiting W1 to greater than or equal to 0.1 mm increases the connection area between the first insulating portion 141 and the first active material layer 113, reducing the risk of the insulating member 14 falling off. Limiting W1 to less than or equal to 1 mm can reduce the amount of insulating member 14 used, reduce the first insulating portion 141's barrier to active ions, and minimize capacity loss in the battery cell 6.

[0241] In some embodiments, the first active material layer 113 includes a main region 1131 arranged along the first direction Z and a thinned region 1132 connected to the main region 1131. The thinned region 1132 is located on a side of the main region 1131 close to the first end surface 1122 along the first direction Z. The thickness of at least a portion of the thinned region 1132 is less than the thickness of the main region 1131. The first insulating portion 141 covers at least a portion of the thinned region 1132 along the thickness direction Y.

[0242] Illustratively, one end of the thinned region 1132 near 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 near the main region 1131 is less than the thickness of the end of the main region 1131 near the thinned region 1132, forming a step 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 near 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.

[0243] Exemplarily, the main body region 1131 is substantially of a uniform thickness, and the average thickness of the thinned region 1132 is smaller than that of the main body region 1131 .

[0244] During the molding process of the first electrode sheet 11, the first active material layer 113 needs to be rolled to increase its compaction density. By providing the thinned region 1132, the present application can reduce the pressure on the edge of the first active material layer 113, thereby reducing 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 thinned region 1132 along the thickness direction Y, thereby improving space utilization.

[0245] In some embodiments, the thickness of the thinned region 1132 at one end near the main region 1131 is equal to the thickness of the main region 1131 at one end near the thinned region 1132. The thickness of the thinned region 1132 gradually decreases as it moves away from the main region 1131. The gradual change in thickness of the thinned region 1132 reduces the risk of step formation on the first active material layer 113 and reduces stress concentration.

[0246] In some embodiments, in the first direction Z, the first insulating portion 141 is spaced apart from the main body region 1131 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.

[0247] 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 ion transmission between the main body region 1131 and the second electrode sheet, thereby reducing the capacity loss of the battery cell.

[0248] 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 main region 1131 away from the first current collecting body 112 .

[0249] 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 .

[0250] In some embodiments, a 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. For example, t1 / t2≤0.5. Alternatively, t1 / t2≤1 / 3.

[0251] The thinning area 1132 has a smaller thickness at the end away from the main area 1131, 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 or falling off of the insulating part 14.

[0252] In some embodiments, the first current collecting body 112 further includes two second end surfaces 1123 . The two second end surfaces 1123 are respectively disposed at two ends of the first end surface 1122 , and each second end surface 1123 connects the two first surfaces 1121 .

[0253] 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.

[0254] 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 .

[0255] In the thickness direction Y, the third insulating portion 143 does not overlap with the first pole piece body 111 .

[0256] Optionally, the third insulating portion 143 may include a first region and a second region arranged along the first direction Z, wherein the first region connects the two first insulating portions 141, and the second region is located on one side of the second insulating portion 142 along the winding direction V and is 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.

[0257] The third insulating portion 143 can cover burrs on the second end surface 1123, thereby reducing the risk of short circuits and improving reliability. The provision of the third insulating portion 143 can also reduce the risk of exposing the first end surface 1122 due to assembly errors.

[0258] In some embodiments, there are two third insulating parts 143 .

[0259] 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, separator 13, and second electrode sheet 12 are wound together. In the winding direction V of the first electrode sheet, both ends of the insulating member 14 do not extend beyond the separator 13.

[0260] For example, as shown in FIG4 , 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 extend beyond the rear end of the separator 13; in the negative direction of the winding direction V, the insulating member 14 does not extend beyond the front end of the separator 13.

[0261] The spacer 13 can restrain the insulating member 14 , maintain the insulating member 14 in close contact with the first pole piece body 111 , and reduce the risk of the insulating member 14 falling off the first pole piece body 111 .

[0262] Exemplarily, in the positive direction of the winding direction V, the tail end of the isolating element 13 extends beyond one third insulating portion 143 of the insulating element 14 . In the negative direction of the winding direction V, the head end of the isolating element 13 extends beyond the other third insulating portion 143 of the insulating element 14 .

[0263] 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.

[0264] In some embodiments, the insulating member 14 includes two independently formed insulating layers 144. The insulating layers 144 include 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, while 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.

[0265] Optionally, the connecting portion 144 b of the two insulating layers 144 further forms a third insulating portion 143 .

[0266] 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.

[0267] In some embodiments, t1 / t2 ≤ 0.5. The thinned region 1132 has a smaller thickness at the end away from the main region 1131. When the insulating layer 144 is attached, the insulating layer 144 is less bent at the end of the thinned region 1132 away from the main region 1131. This helps reduce the risk of a gap between the two insulating layers 144 and improves the connection strength between the two insulating layers 144.

[0268] In some embodiments, the thickness of the insulating layer 144 is 7 μm-30 μm. Alternatively, 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.

[0269] Limiting the thickness of insulating layer 144 to greater than or equal to 7 μm can reduce the risk of puncture of insulating layer 144 by burrs, thereby improving reliability. Limiting the thickness of insulating layer 144 to less than or equal to 30 μm can reduce the space and weight occupied by insulating layer 144, thereby reducing the loss of energy density of battery cell 6.

[0270] 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 no greater than 10 μm.

[0271] 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.

[0272] As t3 increases, the insulating layer 144 is less likely to be punctured by burrs; correspondingly, the insulating layer 144 occupies more space and weighs more. As t4 increases, the current carrying capacity of the first current collecting body 112 increases. However, the burrs generated by the first current collecting body 112 become more severe, making it more likely that the burrs will puncture the insulating layer 144.

[0273] 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.

[0274] 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 .

[0275] 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 .

[0276] In some embodiments, the first end surface 1122 includes a tab lead-out region 1122a and a non-tab lead-out region 1122b. The first tab 114 extends only from the tab lead-out region 1122a and protrudes beyond the second insulating portion 142 in a direction away from the first current collector 112. Two connecting portions 144b directly connect to the non-overlapping portions of the first tab 114 to form a first extension portion 1421. The first extension portion 1421 covers the non-tab lead-out region 1122b along the first direction Z. The overlapping portions of the two connecting portions 144b with the first tab 114 form a second extension portion 1422, which covers at least a portion of the first tab along the thickness direction Y.

[0277] 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.

[0278] 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.

[0279] In some embodiments, the portion of the connecting portion 144b that overlaps with the first tab 114 has a dimension D3 in the first direction Z, and the portion of the connecting portion 144b that does not overlap with the first tab 114 has a dimension D4 that protrudes beyond the non-tab lead-out area 1122b in the first direction Z, and D3 is equal to D4.

[0280] Exemplarily, D3 is equal to D1, and D4 is equal to D2.

[0281] 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 between 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.

[0282] In some embodiments, the insulating layer 144 is rectangular in a flattened state.

[0283] In some embodiments, the width of the insulating layer 144 is 5 mm to 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.

[0284] In some embodiments, the first current collector 112 includes two first end surfaces 1122 disposed opposite each other along a first direction Z, which is perpendicular to a thickness direction Y of the first electrode body 111. The electrode assembly 10 includes two insulating members 14, which are respectively disposed outside the two first end surfaces 1122.

[0285] 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.

[0286] In some embodiments, the second electrode 12 includes a second electrode body 121, which is stacked with the first electrode body 111. The second electrode body 121 includes a second current collector 122 and a second active material layer 123. The second current collector 122 includes two oppositely disposed second surfaces 1221 and a third end surface 1222 connecting the two second surfaces 1221. The second active material layer 123 is disposed on the second surface 1221.

[0287] In some examples, the second electrode sheet 12 is a positive electrode sheet, the positive electrode current collector may include a second current collecting 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 collecting body 122, and the second active material layer 123 is a negative electrode active material layer.

[0288] In the embodiment of the present application, the second active material layer 123 may be provided on one second surface 1221 , or may be provided on both second surfaces 1221 .

[0289] 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, and the third end surface 1222 is located at one end of the second current collecting body 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 .

[0290] For example, 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 the other third end face 1222 near the other first end face 1122 from the first pole piece 11.

[0291] 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 .

[0292] The insulating member 14 can also separate the burrs on the third end face 1222 from the first pole piece 11 , thereby reducing the risk of the burrs on the third end face 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 .

[0293] In some embodiments, the first electrode 11 is a positive electrode, and the second electrode 12 is a negative electrode. In the first direction Z, both ends of the second active material layer 123 extend beyond the first electrode body 111 .

[0294] The insulating member 14 shields at least a portion of the first end surface 1122. Even if the second active material layer 123 overlaps the first end surface 1122 in the stacking direction, it is unlikely to come into contact with 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 enhancing reliability.

[0295] In some embodiments, the electrode assembly 10 further includes a separator 13 for separating 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.

[0296] 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.

[0297] In some embodiments, the melting point of the insulating member 14 is 95°C-150°C.

[0298] 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.

[0299] 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 softening or falling off due to heat, thereby improving reliability.

[0300] 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.

[0301] The colloid has a high bonding strength and is not easy to fall off from the first pole piece body 111 .

[0302] Optionally, the colloid may be a hot melt colloid. The insulating member 14 may be a hot melt adhesive film.

[0303] 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 .

[0304] In some embodiments, the elastic modulus of the insulating member 14 is 500 MPa-3000 MPa.

[0305] 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 .

[0306] 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.

[0307] The insulating member 14 has a high elastic modulus, which can provide support for the first pole tab 114 , reduce the risk of the root of the first pole tab 114 being inserted upside down between the first pole piece 11 and the second pole piece 12 , and improve reliability.

[0308] 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”.

[0309] In some embodiments, the elastic modulus of the insulating member 14 is 770 MPa-1320 MPa.

[0310] 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 .

[0311] The insulating member 14 has a high tensile strength and is not easily deformed when subjected to a tensile force from the first pole piece 114. Accordingly, the insulating member 14 can effectively limit the deformation of the first pole piece 114, reduce the risk of the root of the first pole piece 114 being inserted inverted between the first pole piece 11 and the second pole piece 12, and improve reliability.

[0312] As an example, the tensile strength of the insulating member 14 can be tested with reference to the national standard GB / T 228-2002 “Metallic Materials—Room Temperature Tensile Test Method”.

[0313] 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 .

[0314] As an example, the insulating member 14 can be fixed on a tensile testing machine and pulled 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 .

[0315] As an example, the peel strength can be tested with reference to GB / T 2792-2014 Test method for peel strength of adhesive tapes.

[0316] 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.

[0317] In some embodiments, the battery cell 6 includes an electrolyte contained within the housing 20. The insulator 14 remains stable in the electrolyte.

[0318] Illustratively, after immersion 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 2 N / m. Optionally, after immersion in the electrolyte for 1000 hours, the peel strength between the insulating member 14 and the first active material layer 113 is 15 N / m-200 N / m.

[0319] 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.

[0320] Figure 15 is a schematic diagram of the first pole piece of the electrode assembly provided in other embodiments of the present application in an unfolded state, wherein the pole piece lead-out area is covered by the first pole piece, which is shown by a dotted line in Figure 15; Figure 16 is a schematic diagram of the first pole piece shown in Figure 15 after being connected to the insulating member, wherein the portion of the first pole piece covered by the insulating member is shown by a dotted line; Figure 17 is a schematic cross-sectional view of Figure 16 taken along the DD direction.

[0321] 15 to 17 , in some embodiments, the first surface 1121 includes a coated region 1121 a and an uncoated region 1121 b arranged along a first direction Z. One end of the uncoated region 1121 b is connected to the first end surface 1122 and the other end is connected to the coated region 1121 a. The coated region 1121 a is coated with the first active material layer 113, while the uncoated region 1121 b is not coated with the first active material layer 113. The first insulating portion 141 is connected to the uncoated region 1121 b.

[0322] The provision of the uncoated area 1121b increases the connection area between the first current collector 112 and the insulating member 14, reduces the risk of the insulating member 14 falling off, and improves reliability. The first end surface 1122 is spaced apart from the first active material layer 113 along the first direction Z. This reduces the risk of cutting the first active material layer 113 during cutting of the first electrode sheet 11, thereby reducing waste of active material.

[0323] 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.

[0324] In some embodiments, the first insulating portion 141 completely covers the uncoated area 1121 b to reduce the possibility of electrical conduction between the uncoated area 1121 b and the second pole piece 12 , thereby reducing the risk of short circuit and improving reliability.

[0325] 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.

[0326] 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 easily adhered to the first end surface 1122 .

[0327] In the first direction Z, the size of the area where the insulating member 14 covers the uncoated area 1121b is greater than or equal to 1 mm, so as to increase the connection strength between the insulating member 14 and the uncoated area 1121b and reduce the risk of the insulating member 14 falling off the first pole piece 11.

[0328] Illustratively, in the first direction Z, the size of the area of ​​the insulating member 14 covering the uncoated region 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.

[0329] In some embodiments, W2 is less than or equal to 5 mm. Limiting W2 to less than or equal to 5 mm reduces the space and weight occupied by the insulating member 14, lowers the size requirement of the uncoated area 1121 b, increases the area of ​​the coated area 1121 a, and improves the energy density of the battery cell 6.

[0330] 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 .

[0331] 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 .

[0332] Exemplarily, for the insulating member 14 attached to the first end face 1122 of the lead-out first electrode tab 114, the size 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 size of the area where the insulating member 14 overlaps with the uncoated area 1121b along the first direction Z is 3 mm, and the size of the second insulating portion 142 along the first direction Z is 4.5 mm.

[0333] For the insulating member 14 attached to the first end surface 1122 where the first 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.

[0334] FIG18 is a schematic diagram of an insulating member provided in some embodiments of the present application before being assembled to the first pole piece.

[0335] 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 .

[0336] In some embodiments, the insulating member 14 defines a channel 142 a for the first electrode tab 114 to pass through.

[0337] For example, before assembling the first pole piece 11 and the insulating member 14, the insulating member 14 can be a flat plate. The first pole tab 114 can be aligned with the channel 142a of the insulating member 14 and passed through the channel 142a. After the insulating member 14 abuts against the first end surface 1122, the insulating member 14 can be folded over to attach it to the first pole piece body 111.

[0338] Figure 19 is a schematic diagram of the first pole piece and the insulating member of the electrode assembly provided in some other embodiments of the present application in the unfolded state, wherein the portion of the first pole piece covered by the insulating member is shown by a dotted line; Figure 20 is an enlarged schematic diagram of Figure 19 at the circle frame.

[0339] 19 and 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 providing 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.

[0340] 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.

[0341] Figure 21 is a schematic structural diagram of the insulating part of the electrode assembly provided in some embodiments of the present application.

[0342] 21 , in some embodiments, the insulating member 14 includes a base material layer 145 and an adhesive layer 146 , and the base material layer 145 is connected to the first pole piece body 111 through the adhesive layer 146 .

[0343] The substrate layer 145 can enhance the strength of the insulating member 14 and reduce deformation of the insulating member 14 during attachment. The adhesive layer 146 can adhere the substrate layer 145 to the first pole piece body 111 to reduce the risk of the substrate layer 145 falling off the first pole piece body 111.

[0344] In some embodiments, the substrate layer 145 includes at least one of polyethylene terephthalate (PET), polypropylene, polyethylene, and block copolymers thereof.

[0345] In some embodiments, the adhesive layer 146 includes at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene, or butyl rubber.

[0346] 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 together. Optionally, the insulating layer 144 is a pressure-sensitive adhesive tape.

[0347] In some embodiments, the elastic modulus of the substrate layer 145 is greater than the elastic modulus of the adhesive layer 146 .

[0348] FIG22 is a schematic partial cross-sectional view of an electrode assembly provided in some other embodiments of the present application.

[0349] 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 .

[0350] In some embodiments, the second pole piece 12 includes a second pole tab 124 extending from a third end surface 1222 .

[0351] In some embodiments, the electrode assembly 10 includes two insulating members 14 respectively attached to the two third end surfaces 1222 .

[0352] For example, 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 region where the insulating member 14 overlaps with the second active material layer 123 along the first direction Z is 0.5 mm.

[0353] 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.

[0354] FIG23 is a schematic top view of an electrode assembly provided in some other embodiments of the present application; FIG24 is a schematic cross-sectional view of FIG23 taken along the FF direction.

[0355] 23 and 24 , in some embodiments, the electrode assembly 10 further includes a separator 13 for separating the first electrode piece 11 from the second electrode piece 12 . In the first direction Z, one end of the second insulating portion 142 away from the first insulating portion 141 extends beyond the separator 13 .

[0356] The second insulating portion 142 protrudes from the separator 13. When the first electrode tab 114 is bent, the second insulating portion 142 can limit the first electrode tab 114, reduce the risk of the first electrode tab 114 squeezing the separator 13, alleviate wrinkles of the separator 13, reduce the risk of the separator 13 shrinking inward, and improve reliability.

[0357] In some embodiments, one end of the first current collecting body 112 along the first direction Z exceeds the second pole piece body 121 .

[0358] FIG25 is a schematic cross-sectional view of the first pole piece and the insulating member of the electrode assembly provided in some other embodiments of the present application.

[0359] 25 , in some embodiments, the first insulating portion 141 covers a portion of the main region 1131. The first insulating portion 141 is connected to both the main region 1131 and the thinned region 1132, thereby increasing the connection area between the insulating member 14 and the first pole piece body 111 and reducing the risk of the insulating member 14 falling off.

[0360] Figure 26 is a schematic diagram of an electrode assembly provided in some other embodiments of the present application. In Figure 26 , the first electrode body 111 is shown by a dotted line.

[0361] 26 , in some embodiments, the first pole piece body 111 is flat, and in the second direction X, both ends of the insulating member 14 do not extend beyond the isolation member 13 . The second direction X is perpendicular to the first direction Z and the thickness direction Y.

[0362] 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 .

[0363] 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 .

[0364] 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, with one first pole piece 11 sandwiched between adjacent folded segments.

[0365] The spacer 13 can restrain the insulating member 14 , maintain the insulating member 14 in close contact with the first pole piece body 111 , and reduce the risk of the insulating member 14 falling off the first pole piece body 111 .

[0366] Figure 27 is a schematic diagram of the first pole piece and insulating member of the electrode assembly provided in some other embodiments of the present application in the unfolded state.

[0367] 27 , in some embodiments, the second insulating portion 142 is only provided 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.

[0368] Exemplarily, there are multiple second insulating portions 142 , which are spaced apart from each other, and each second insulating portion 142 covers a non-tab lead-out area 1122 b .

[0369] 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 .

[0370] According to some embodiments of the present application, the present application also provides a battery comprising a plurality of battery cells according to any of the above embodiments.

[0371] According to some embodiments of the present application, the present application further provides an electrical device comprising a battery cell according to any of the above embodiments, the battery cell being used to provide electrical energy to the electrical device. The electrical device may be any of the aforementioned devices or systems using the battery cell.

[0372] According to some embodiments of the present application, referring to Figures 4 to 14, embodiments of the present application provide an electrode assembly 10, including a first electrode sheet 11, a second electrode sheet 12, a separator 13, and an insulating member 14. The first electrode sheet 11 and the second electrode sheet 12 have opposite polarities, and the first electrode sheet 11, the second electrode sheet 12, and the separator 13 are wound along a winding direction V to form a wound structure.

[0373] The first electrode 11 includes a first electrode body 111 and a first electrode tab 114. The first electrode 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 each other along the thickness direction Y of the first electrode body 111. The two first end surfaces 1122 are respectively located at the ends of the first current collector 112 along the first direction Z. The two second surfaces 1221 are respectively located at the 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.

[0374] The first surface 1121 includes a coated area 1121a and an uncoated area 1121b arranged along a first direction Z. The first active material layer 113 is disposed in the coated area 1121a, while the uncoated area 1121b is not provided with the first active material layer 113. One end of the uncoated area 1121b away from the coated area 1121a is connected to one first end surface 1122, and one end of the coated area 1121a away from the uncoated area 1121b is connected to the other first end surface 1122.

[0375] 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 .

[0376] An insulating member 14 is used to cover the first end face 1122 from which the first electrode tab 114 is led. Specifically, the insulating member 14 is connected to the first active material layer 113 and covers the uncoated region 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.

[0377] Another insulating member 14 is used to cover the first end surface 1122 where the first tab 114 is not led out. Specifically, the other 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 .

[0378] 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 layers 144 can be hot melt adhesive films or pressure sensitive adhesive tapes.

[0379] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0380] 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 them. 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. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An electrode assembly, comprising a first electrode tab and a second electrode tab with opposite polarities; The first electrode tab includes a first electrode tab body, the first electrode tab body includes a first current collector body and a first active material layer, the first current collector body includes two first surfaces oppositely arranged along its own thickness direction and a first end surface connecting the two first surfaces, and the first active material layer is disposed on the first surface; The electrode assembly further includes an insulating member connected to the first electrode tab body, at least a part of the insulating member is disposed outside the first end surface along a first direction, and the first direction is perpendicular to the thickness direction.

2. The electrode assembly according to claim 1, wherein, 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 electrode tab body along the thickness direction and are connected to the first electrode tab body; The second insulating portion connects the two first insulating portions and is disposed outside the first end surface along the first direction.

3. The electrode assembly according to claim 2, wherein, The second insulating portion covers at least a part of the first end surface.

4. The electrode assembly according to claim 2 or 3, wherein, The first electrode tab further includes a first tab connected to the first current collector body, the first end surface includes a tab lead-out area and a non-tab lead-out area, the first tab is only led out from the tab lead-out area, and protrudes from the second insulating portion in the first direction away from the first current collector body.

5. The electrode assembly according to claim 4, wherein, The second insulating portion covers at least a part of the non-tab lead-out area.

6. The electrode assembly according to claim 5, wherein, The second insulating portion is only disposed outside the non-tab lead-out area along the first direction.

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

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

9. The electrode assembly according to claim 8, wherein, 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.

10. The electrode assembly according to claim 8, wherein, 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 dimension of the second part along the first direction is equal to the dimension of the second extension portion along the first direction, the first part is configured to form a recess on the second insulating portion, and the dimension of the first part along the first direction is smaller than the dimension of the second extension portion along the first direction.

11. The electrode assembly according to any one of claims 7-10, wherein, In the first direction, the dimension of the root area of the first tab covered by the second extension portion is greater than or equal to 0.2 times the dimension of the first tab and less than or equal to 0.6 times the dimension of the first tab.

12. The electrode assembly according to any one of claims 2-11, wherein, The first insulating portion is connected to the first active material layer.

13. The electrode assembly according to claim 12, wherein, At least a part 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, wherein, The first active material layer includes a main body region disposed along the first direction and a thinning region connected to the main body region. The thinning region is located on a side of the main body region closer to the first end face along the first direction, and at least a part of the thickness of the thinning region is less than the thickness of the main body region; The first insulating portion covers at least a part of the thinning region along the thickness direction.

15. The electrode assembly according to claim 14, wherein, Along the direction from the first current collector main body to the first active material layer, the first insulating portion does not extend beyond the surface of the main body region facing away from the first current collector main body.

16. The electrode assembly according to claim 14 or 15, wherein, In the first direction, the first insulating portion is spaced apart from the main body region.

17. The electrode assembly according to claim 14, wherein, The first insulating portion covers a part of the main body region.

18. The electrode assembly according to any one of claims 14-17, wherein, The thickness t1 of the end of the thinning region away from the main body region is less than or equal to 0.5 times the thickness t2 of the main body region.

19. The electrode assembly according to any one of claims 2-18, wherein, The first surface includes a coating region and an uncoated region disposed along the first direction. One end of the uncoated region is connected to the first end face, and the other end is connected to the coating region. The coating region is coated with the first active material layer, and the uncoated region 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, wherein, The first insulating portion completely covers the uncoated region.

21. The electrode assembly according to claim 19 or 20, wherein, In the first direction, the size of the region where the insulating member covers the uncoated region is greater than or equal to 1 mm.

22. The electrode assembly according to any one of claims 19-21, wherein, The first electrode tab further includes a first tab, and the first tab extends outward from the first end face along the first direction and passes through the second insulating portion.

23. The electrode assembly according to any one of claims 2-22, wherein, The insulating member includes two independently formed insulating layers. The insulating layer includes an insulating main body and a connecting portion connected to the insulating main body; in the thickness direction, the insulating main body overlaps with the first electrode tab main body, and the connecting portion does not overlap with the first electrode tab main body; The insulating main bodies of the two insulating layers respectively form the two first insulating portions; the two insulating layers The connecting portions of are stacked and connected to form the second insulating portion.

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

25. The electrode assembly according to claim 23 or 24, wherein, The insulation value of the difference between the thickness of the insulating layer and the thickness of the first current collector main body is not greater than 10 μm, optionally not greater than 5 μm.

26. The electrode assembly according to any one of claims 23-25, wherein, The first end face includes a tab lead-out region and a non-tab lead-out region. The first tab extends only from the tab lead-out region and protrudes from the second insulating portion along a direction away from the first current collector main body; The non-overlapping parts of the two connecting portions and the first tab are directly connected to form a first extension portion, and the first extension portion covers the non-tab lead-out region along the first direction; The overlapping parts of the two connecting portions and the first tab form a second extension portion and cover at least a part of the first tab along the thickness direction.

27. The electrode assembly according to claim 26, wherein, The size of the first extension portion along the first direction is equal to the size of the second extension portion along the first direction.

28. The electrode assembly according to any one of claims 2-22, wherein, The insulating member is an integrally formed structure.

29. The electrode assembly according to any one of claims 2-28, wherein, The first current collector main body further includes two second end faces, and the two second end faces are respectively disposed at both 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 part of the second end face.

30. The electrode assembly according to any one of claims 2-29, wherein, The first current collector body includes two first end faces oppositely arranged in a first direction, and the first direction is perpendicular to the thickness direction of the first electrode tab body; The electrode assembly includes two insulating members, and the two insulating members are respectively arranged outside the two first end faces.

31. The electrode assembly according to any one of claims 2-30 further includes a separator for separating the first electrode tab from the second electrode tab; In the first direction, one end of the second insulating portion away from the first insulating portion extends beyond the separator.

32. The electrode assembly according to any one of claims 2-30 further includes a separator for separating the first electrode tab from the second electrode tab; In the first direction, one end of the second insulating portion away from the first insulating portion does not extend beyond the separator.

33. The electrode assembly according to any one of claims 1-32, wherein, The second electrode tab includes a second electrode tab body, and the second electrode tab body is stacked with the first electrode tab body; The second electrode tab body includes a second current collector body and a second active material layer. The second current collector body includes two opposite second surfaces and a third end face connecting the two second surfaces, and the second active material layer is disposed on the second surface; The first end face is located at one end of the first current collector body in the first direction, and the third end face is located at One end of the second current collector body in the first direction; In the thickness direction, the insulating member separates the third end face from the first electrode tab.

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

35. The electrode assembly according to any one of claims 1-34, wherein, The melting point of the insulating member is 95°C - 150°C.

36. The electrode assembly according to any one of claims 1-35, wherein, 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.

37. The electrode assembly according to any one of claims 1 to 36, wherein, The insulating member includes a base material layer and an adhesive layer, and the base material layer is connected to the first electrode tab body through the adhesive layer.

38. The electrode assembly according to claim 37, wherein, The base material layer includes at least one of polyethylene terephthalate, polypropylene, polyethylene and its block copolymers; The adhesive layer includes at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene or butyl rubber.

39. The electrode assembly according to any one of claims 1-38, wherein, The elastic modulus of the insulating member is 500 Mpa - 3000 Mpa. Optionally, the elastic modulus of the insulating member is 770 Mpa - 1320 Mpa.

40. The electrode assembly according to any one of claims 1-39, wherein, The tensile strength of the insulating part is 949 kgf / cm 2 -1363 kgf / cm 2 .

41. The electrode assembly according to any one of claims 1-40, wherein, 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 any one of claims 1-41 further includes a separator for separating the first electrode tab from the second electrode tab; The first pole piece, the separator, and the second pole piece are wound. In the winding direction of the first pole piece, both ends of the insulating member do not extend beyond the separator; alternatively, the main body of the first pole piece is flat, and in a second direction perpendicular to the first direction and the thickness direction, both ends of the insulating member do not extend beyond the separator.

43. A battery cell, comprising: a housing; The electrode assembly according to any one of claims 1-42, accommodated in the housing.

44. A battery, comprising a plurality of battery cells according to claim 43.

45. An electrical device, comprising the battery according to claim 44, the battery being used to provide electrical energy.

Images