Battery monomer, battery and electric equipment

Abstract

The invention discloses a battery monomer, a battery and electric equipment. The battery monomer comprises an electrode assembly, the electrode assembly comprises a positive pole piece and a negative pole piece, the positive pole piece comprises a first edge in a first direction, the negative pole piece comprises a second edge corresponding to the first edge, and the first edge exceeds the second edge in the first direction. According to the technical scheme of the embodiment, the reliability of the battery can be improved.

Description

Battery cells, batteries and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application CN202323010601.4, filed on November 7, 2023, entitled “Battery Cell, Battery and Electrical Equipment,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0005] During the manufacturing process of batteries, battery reliability is an issue that cannot be ignored. Therefore, how to improve battery reliability is a technical problem that needs to be solved urgently in battery technology.

[0006] Summary of the Invention

[0007] The present application provides a battery cell, a battery, and an electrical device, which can improve the reliability of the battery.

[0008] This application is achieved through the following technical solutions:

[0009] In a first aspect, an embodiment of the present application provides a battery cell, which includes an electrode assembly, the electrode assembly including a positive electrode sheet and a negative electrode sheet, the positive electrode sheet including a first edge in a first direction, the negative electrode sheet including a second edge corresponding to the first edge, and the first edge exceeds the second edge along the first direction.

[0010] According to the battery cell of the embodiment of the present application, the first edge of the positive electrode sheet exceeds the second edge of the negative electrode sheet, which can reduce the impact of the edge of the positive electrode sheet on the extrusion and shearing of the negative electrode sheet during the charge and discharge cycle of the battery cell, reduce the probability of the negative electrode sheet being sheared and broken, and thus improve the reliability of the battery cell composed of the electrode assembly.

[0011] According to some embodiments of the present application, the thickness of the negative electrode sheet is H1, and the thickness of the positive electrode sheet is H2, satisfying H1<H2.

[0012] In the above solution, the thickness of the negative electrode sheet is smaller than that of the positive electrode sheet, and the first edge of the positive electrode sheet exceeds the second edge of the negative electrode sheet, which can reduce the risk of the negative electrode sheet being sheared and broken by the positive electrode sheet.

[0013] According to some embodiments of the present application, the thickness of the negative electrode sheet is H1, which satisfies 5 μm≤H1≤100 μm.

[0014] In the above solution, the thickness of the negative electrode sheet satisfies the above relationship, the processing and manufacturing difficulty is low, and the negative electrode sheet has high strength.

[0015] According to some embodiments of the present application, 10 μm≤H1≤80 μm.

[0016] In the above solution, the negative electrode sheet has higher strength and can be provided with more active materials.

[0017] According to some embodiments of the present application, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is arranged on the surface of the positive electrode current collector, the positive electrode current collector has a first edge, and the positive electrode sheet also includes a positive electrode tab, which extends from the first edge.

[0018] In the above solution, the first edge is an edge extending from the positive electrode tab, so as to facilitate electrical connection between the positive electrode tab and the positive electrode terminal.

[0019] According to some embodiments of the present application, along the first direction, the second edge exceeds the positive electrode active material layer, the positive electrode current collector has a first empty foil area, the first empty foil area is located between the first edge and the positive electrode active material layer, the electrode assembly also includes a first insulating member, the first insulating member covers the first empty foil area, and along the thickness direction of the positive electrode sheet, the orthographic projection of the second edge falls within the orthographic projection of the first insulating member.

[0020] In the above scheme, the second edge of the negative electrode sheet extends beyond the positive electrode active material layer, and a first insulating member is arranged in the first empty foil area. Along the thickness direction of the positive electrode sheet, the orthographic projection of the second edge falls within the orthographic projection of the first insulating member, so that the height of the step of the positive electrode sheet near the edge of the positive electrode active material layer (the step is formed by the edge of the positive electrode active material layer) is relatively low, which can reduce the effect of the step on the positive electrode sheet on the extrusion and shearing of the negative electrode sheet during the charge and discharge cycle of the battery cell, and effectively reduce the probability of the negative electrode sheet being sheared and broken.

[0021] According to some embodiments of the present application, along the thickness direction of the positive electrode sheet, the surface of the first insulating member facing away from the positive current collector does not exceed the surface of the positive active material layer facing away from the positive current collector.

[0022] In the above scheme, the surface of the first insulating member facing away from the positive electrode current collector does not exceed the surface of the positive electrode active material layer facing away from the positive electrode current collector, thereby realizing a buffered transition from the positive electrode active material layer to the first insulating member, so as to reduce the height difference of the positive electrode plate at the edge of the positive electrode active material layer, thereby reducing the risk of the negative electrode plate being sheared and broken during the charge and discharge cycle of the battery cell.

[0023] According to some embodiments of the present application, the first insulating member is an insulating coating or an insulating adhesive layer.

[0024] In the above solution, when the first insulating member is assembled with the positive electrode sheet, the insulating coating is sprayed onto the surface of the positive electrode current collector. After drying and solidifying, the insulating coating becomes the first insulating member, which is easy to handle. Alternatively, the first insulating member can be an insulating adhesive layer adhered to the surface of the positive electrode current collector, which is simple to operate and has low processing difficulty.

[0025] According to some embodiments of the present application, the positive electrode plate further has a third edge, which is arranged opposite to the first edge along the first direction, and the negative electrode plate further has a fourth edge corresponding to the third edge, which is arranged opposite to the second edge along the first direction, and along the first direction, the third edge exceeds the fourth edge.

[0026] In the above solution, the third edge exceeds the fourth edge, which can reduce the impact of the edge of the positive electrode sheet on the negative electrode sheet at the end away from the first edge in the first direction, and further reduce the probability of the negative electrode sheet being sheared and broken.

[0027] According to some embodiments of the present application, the positive electrode plate includes a positive electrode collector and a positive electrode active material layer, the positive electrode active material layer is arranged on the surface of the positive electrode collector, along the first direction, the fourth edge exceeds the positive electrode active material layer, the positive electrode collector has a second empty foil area, the second empty foil area is located between the third edge and the positive electrode active material layer, the electrode assembly also includes a second insulating member, the second insulating member covers the second empty foil area, along the thickness direction of the positive electrode plate, the orthographic projection of the fourth edge falls within the orthographic projection of the second insulating member.

[0028] In the above scheme, the second insulating member is arranged in the second empty foil area, and the orthographic projection of the fourth edge along the thickness direction of the positive electrode sheet falls within the orthographic projection of the second insulating member, so that at the end of the positive electrode sheet close to the third edge, the height of the step near the edge of the positive electrode active material layer is lower, which can reduce the effect of the step on the positive electrode sheet on the extrusion and shearing of the negative electrode sheet during the charge and discharge cycle of the battery cell, and effectively reduce the probability of the negative electrode sheet being sheared and broken.

[0029] According to some embodiments of the present application, along the thickness direction of the positive electrode sheet, the surface of the second insulating member facing away from the positive current collector does not exceed the surface of the positive active material layer facing away from the positive current collector.

[0030] In the above scheme, the surface of the second insulating member facing away from the positive electrode current collector does not exceed the surface of the positive electrode active material layer facing away from the positive electrode current collector, and a height transition from the positive electrode active material layer to the second insulating member can be achieved in the first direction, so as to reduce the height difference of the positive electrode plate at the edge of the positive electrode active material layer, so as to reduce the risk of the negative electrode plate being sheared and broken during the charge and discharge cycle of the battery cell.

[0031] According to some embodiments of the present application, the second insulating member is an insulating coating applied to the positive electrode current collector, or the second insulating member is an insulating adhesive layer applied to the positive electrode current collector.

[0032] In the above solution, when the second insulating member is assembled with the positive electrode sheet, the insulating coating is sprayed onto the surface of the positive electrode current collector. After the insulating coating dries and solidifies, it becomes the second insulating member, which is easy to handle. Alternatively, the second insulating member can be an insulating adhesive layer adhered to the surface of the positive electrode current collector, which is simple to operate and has low processing difficulty.

[0033] According to some embodiments of the present application, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is arranged on the surface of the positive electrode current collector, and along the first direction, the positive electrode active material layer extends to the third edge.

[0034] In the above scheme, the positive electrode active material layer extends to the third edge, which can eliminate the step of the positive electrode plate at one end close to the third edge, reduce the risk of the edge of the positive electrode active material layer squeezing and shearing the negative electrode plate, and reduce the risk of the negative electrode plate being sheared and broken during the charge and discharge cycle of the battery cell.

[0035] According to some embodiments of the present application, the electrode assembly further includes a third insulating member, and a portion of the third insulating member is disposed at a portion of the positive electrode active material layer that exceeds the fourth edge.

[0036] In the above solution, part of the third insulating member is arranged at the portion of the positive electrode active material layer that exceeds the fourth edge, which can reduce the risk of metal ions precipitating on the surface of the negative electrode sheet and causing a short circuit between the positive and negative electrodes.

[0037] According to some embodiments of the present application, along the thickness direction of the positive electrode sheet, the orthographic projection of the fourth edge falls within the orthographic projection of the third insulating member, and the thickness of the third insulating member is less than the thickness of the positive electrode active material layer.

[0038] In the above scheme, the thickness of the third insulating member is less than the thickness of the positive electrode active material layer, and the height difference between the third insulating member and the positive electrode active material layer is small, which can reduce the shear effect on the negative electrode electrode, and the third insulating member occupies a smaller assembly space; at the same time, the orthographic projection of the fourth edge falls within the orthographic projection of the third insulating member, which can reduce the risk of metal ions precipitating on the surface of the negative electrode current collector and damaging the isolation membrane, and reduce the risk of short circuit between the positive and negative electrodes.

[0039] According to some embodiments of the present application, the third insulating member is an insulating coating or an insulating adhesive layer.

[0040] In the above solution, when the third insulating member is assembled with the positive electrode sheet, an insulating coating is sprayed onto the surface of the positive electrode active material layer. After the insulating coating dries and solidifies, it forms the third insulating member, which is easy to handle. Alternatively, the third insulating member can be an insulating adhesive layer adhered to the surface of the positive electrode active material layer, which is simple to handle and has low processing difficulty.

[0041] According to some embodiments of the present application, the positive electrode plate further has a third edge, a fifth edge and a sixth edge, the third edge is arranged opposite to the first edge along the first direction, the fifth edge connects the first end of the first edge and the first end of the third edge, the sixth edge connects the second end of the first edge and the second end of the third edge, and the negative electrode plate further has a seventh edge corresponding to the fifth edge, and an eighth edge corresponding to the sixth edge, along the second direction, the fifth edge exceeds the seventh edge, and / or the sixth edge exceeds the eighth edge, and the second direction is perpendicular to the first direction.

[0042] In the above scheme, the fifth edge exceeds the seventh edge, and / or the sixth edge exceeds the eighth edge, further reducing the impact of the edge of the positive electrode sheet on the extrusion and shearing of the negative electrode sheet during the charge and discharge cycle of the battery cell, reducing the probability of the negative electrode sheet being sheared and broken, thereby improving the reliability of the battery cell composed of the electrode assembly.

[0043] According to some embodiments of the present application, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is arranged on the surface of the positive electrode current collector, and along the second direction, the positive electrode active material layer extends to the fifth edge, and / or, the positive electrode active material layer extends to the sixth edge.

[0044] In the above scheme, the positive electrode active material layer extends to the fifth edge and / or the sixth edge, which can eliminate the steps at both ends of the positive electrode plate in the second direction, further reduce the risk of the edge of the positive electrode active material layer squeezing and shearing the negative electrode plate, and reduce the risk of the negative electrode plate being sheared and broken during the charge and discharge cycle of the battery cell.

[0045] According to some embodiments of the present application, the electrode assembly further includes a fourth insulating member, part of which is arranged at a portion of the positive electrode active material layer that exceeds the seventh edge, the thickness of the fourth insulating member is less than the thickness of the positive electrode active material layer, and along the thickness direction of the positive electrode sheet, the orthographic projection of the seventh edge falls within the orthographic projection of the fourth insulating member; and / or, the electrode assembly further includes a fifth insulating member, part of which is arranged at a portion of the positive electrode active material layer that exceeds the eighth edge, the thickness of the fifth insulating member is less than the thickness of the positive electrode active material layer, and along the thickness direction of the positive electrode sheet, the orthographic projection of the eighth edge falls within the orthographic projection of the fifth insulating member.

[0046] In the above solution, the thickness of the fourth insulating member is less than the thickness of the positive electrode active material layer, the height difference between the fourth insulating member and the positive electrode active material layer is small, and / or the thickness of the fifth insulating member is less than the thickness of the positive electrode active material layer, and the height difference between the fifth insulating member and the positive electrode active material layer is small, which can reduce the shearing effect on the negative electrode pole piece and reduce the risk of the negative electrode pole piece being sheared and broken, and the fourth and fifth insulating members occupy a smaller assembly space. At the same time, the orthographic projection of the seventh edge falls within the orthographic projection of the fourth insulating member, and / or the orthographic projection of the eighth edge falls within the orthographic projection of the fifth insulating member, which can reduce the risk of metal ions precipitating on the surface of the negative electrode current collector and damaging the separator, and reduce the risk of short circuit between the positive and negative electrodes.

[0047] According to some embodiments of the present application, the fourth insulating member is an insulating coating or an insulating adhesive layer; and / or the fifth insulating member is an insulating coating or an insulating adhesive layer.

[0048] In the above scheme, the fourth insulating member and the fifth insulating member can be insulating coatings sprayed on the surface of the positive electrode active material layer, or the fourth insulating member and the fifth insulating member can be insulating glue layers adhered to the surface of the positive electrode active material layer, which is simple to operate and has low processing and manufacturing difficulty.

[0049] According to some embodiments of the present application, the negative electrode plate includes a negative electrode current collector and a metal layer, and the metal layer is arranged on the surface of the negative electrode current collector.

[0050] In the above solution, the metal layer has a thinner thickness. When the first edge exceeds the second edge, the risk of the negative electrode sheet being sheared and broken due to the extrusion and shearing of the positive electrode sheet on the negative electrode collector and the metal layer can be reduced, thereby improving the reliability of the battery cell.

[0051] According to some embodiments of the present application, the negative electrode current collector is copper foil, and the metal layer is a lithium metal layer; or, the negative electrode current collector is aluminum foil or copper foil, and the metal layer is a sodium metal layer.

[0052] In the above solution, the metal layer is a lithium metal layer or a sodium metal layer, which can make the battery cell have higher mass energy density and volume energy density.

[0053] According to some embodiments of the present application, the negative electrode plate includes a negative electrode current collector, and no active material layer is provided on the surface of the negative electrode current collector.

[0054] In the above solution, no active material layer is provided on the surface of the negative electrode current collector, which can reduce materials and lower costs.

[0055] According to some embodiments of the present application, a dimension X of the first edge extending beyond the second edge satisfies 0.3 mm ≤ X ≤ 8 mm.

[0056] In the above solution, the dimension of the first edge exceeding the second edge satisfies the above relationship, the processing and manufacturing difficulty is low, and the impact on the energy and energy density of the battery cell is small.

[0057] According to some embodiments of the present application, 1.5 mm ≤ X ≤ 4 mm.

[0058] In the above solution, compared with 0.3 mm ≤ X ≤ 8 mm, when 1.5 mm ≤ X ≤ 4 mm, it is easier to process and manufacture, and the impact on the energy and energy density of the battery cell is further reduced.

[0059] In a second aspect, an embodiment of the present application provides a battery, comprising a battery cell as provided in any of the above embodiments.

[0060] In a third aspect, an embodiment of the present application provides an electrical device, comprising a battery cell or battery as provided in any of the above embodiments, wherein the battery cell or battery is used to provide electrical energy.

[0061] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. 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. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these 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 an exploded view of a battery provided in some embodiments of the present application;

[0065] FIG3 is an exploded view of a battery cell provided in some embodiments of the present application;

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

[0067] FIG5 is a cross-sectional view of an electrode assembly provided in some embodiments of the present application;

[0068] FIG6 is a schematic diagram of the assembly of a first insulating member and a positive electrode plate according to some embodiments of the present application;

[0069] FIG7 is a schematic diagram of the assembly of a second insulating member and a positive electrode plate according to some embodiments of the present application;

[0070] FIG8 is a schematic diagram of the assembly of a third insulating member and a positive electrode plate according to some embodiments of the present application;

[0071] FIG9 is a partial enlarged view of point A in FIG8 ;

[0072] FIG10 is a cross-sectional view of an electrode assembly provided in some other embodiments of the present application;

[0073] FIG11 is a schematic diagram of the assembly of the fourth insulating member, the fifth insulating member, and the positive electrode sheet according to some embodiments of the present application;

[0074] FIG12 is a schematic diagram of the assembly of the sixth insulating member, the seventh insulating member and the positive electrode plate provided in some embodiments of the present application.

[0075] In the drawings, the drawings are not drawn to scale.

[0076] Marking instructions: 100 - battery; 10 - housing; 11 - first sub-housing; 12 - second sub-housing; 20 - battery cell; 21 - housing; 211 - housing; 212 - end cap; 22 - electrode assembly; 220 - separator; 221 - positive electrode sheet; 221a - first edge; 221b - third edge; 221c - fifth edge; 221d - sixth edge; 2211 - positive electrode current collector; 2212 - positive electrode active material layer; 2213 - positive electrode tab; 2214 - first main body; 2215 - first empty foil area; 2216 - second empty foil area; 2217 - third empty foil area; 2218 - fourth empty foil area; 222 -Negative electrode sheet; 222a-second edge; 222b-fourth edge; 222c-seventh edge; 222d-eighth edge; 2221-negative current collector; 2222-metal layer; 2223-negative electrode tab; 2224-second main body; 223-first insulating member; 224-second insulating member; 225-third insulating member; 226-fourth insulating member; 227-fifth insulating member; 228-sixth insulating member; 229-seventh insulating member; 23-electrode terminal; 24-adapter; 200-controller; 300-motor; 1000-vehicle; X-first direction; Y-second direction; Z-thickness direction of the positive electrode sheet. DETAILED DESCRIPTION

[0077] 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 and completely 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.

[0078] 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 only for the purpose of describing specific embodiments 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.

[0079] 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. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0080] 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.

[0081] 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.

[0082] The term "multiple" in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0083] 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.

[0084] 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.

[0085] 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.

[0086] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0087] 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.

[0088] The battery cells may be, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, and the like.

[0089] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0090] 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 disposed on at least one surface of the positive electrode current collector.

[0091] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0092] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. 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.).

[0093] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used.

[0094] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0095] As an example, the negative electrode current collector may be a metal foil or a composite current collector. For example, the metal foil may be silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium.

[0096] In some embodiments, the negative electrode current collector has two opposite surfaces in its thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0097] As an example, the negative electrode active material may be a negative electrode active material for a battery 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 be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0098] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0099] As an example, the primary material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0100] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0101] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0102] In some embodiments, the electrode assembly is a laminate structure.

[0103] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0104] In some embodiments, the housing includes an end cap and a shell. The shell has an opening, and the end cap closes the opening to form a sealed space for accommodating the electrode assembly, electrolyte, and other substances. The shell may have one or more openings. One or more end caps may also be provided.

[0105] In some embodiments, the housing is provided with at least one electrode terminal, which is electrically connected to a tab of the electrode assembly. The electrode terminal may be directly connected to the tab or indirectly connected to the tab via an adapter. The electrode terminal may be provided on an end cap or on the housing.

[0106] In some embodiments, the housing is provided with an explosion-proof valve for releasing the internal pressure of the battery cell.

[0107] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, and a polygonal battery. The polygonal battery is, for example, a hexagonal battery, etc. There is no special limitation in the embodiments of the present application.

[0108] The development of battery technology must take into account multiple design factors at the same time, such as energy density, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery reliability must also be considered.

[0109] In some embodiments, the edge of the negative electrode sheet typically exceeds the edge of the positive electrode sheet to reduce the risk of a positive-negative electrode short circuit caused by metal ion precipitation. However, since the projection of the positive electrode sheet falls on the negative electrode sheet, during the charge and discharge cycle of the battery cell, the electrode assembly repeatedly expands and contracts. When the electrode assembly expands, the positive electrode sheet squeezes the negative electrode sheet, which can cause the edge of the positive electrode sheet (including but not limited to the edge of the positive electrode current collector and the edge of the positive electrode active material layer) to squeeze and shear the corresponding negative electrode sheet, making the negative electrode sheet easily sheared and broken during the charge and discharge cycle of the battery cell, resulting in poor performance of the battery cell, and even the risk of the broken negative electrode sheet puncturing the separator and causing a positive-negative electrode short circuit, thereby reducing the reliability of the battery cell.

[0110] In view of this, an embodiment of the present application provides a technical solution, in which an electrode assembly includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet includes a first edge in a first direction, and the negative electrode sheet includes a second edge corresponding to the first edge. Along the first direction, the first edge exceeds the second edge, which can improve the reliability of the battery cell.

[0111] In a battery cell composed of such an electrode assembly, since the first edge of the positive electrode sheet exceeds the second edge of the negative electrode sheet, during the charge and discharge cycle of the battery cell, the first edge will not squeeze and shear the negative electrode sheet, so as to reduce the impact of the edge of the positive electrode sheet on the squeezing and shearing of the negative electrode sheet, thereby reducing the probability of the negative electrode sheet being sheared and broken, extending the service life of the negative electrode sheet, and making the battery cell have higher reliability.

[0112] The battery disclosed in the embodiments of the present application can be used, but is not limited to, in electrical equipment such as vehicles, ships, or aircraft. The battery disclosed in the present application can be used to form a power supply system for the electrical equipment.

[0113] The embodiments of the present application provide an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, an electric bicycle, an electric motorcycle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0114] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0115] Please refer to Figure 1, which is a schematic diagram of the structure of the vehicle provided in some embodiments of the present application. Vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power source for the vehicle 1000, for the circuit system of the vehicle 1000, such as for the working power requirements during the startup, navigation and operation of the vehicle 1000.

[0116] The vehicle 1000 may further include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0117] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0118] Please refer to Figure 2, which is an exploded view of a battery provided in some embodiments of the present application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 being housed within the housing 10. The housing 10 is used to provide a storage space for the battery cell 20, and the housing 10 can adopt a variety of structures. In some embodiments, the housing 10 can include a first sub-housing 11 and a second sub-housing 12, which cover each other and together define a storage space for accommodating the battery cell 20. The second sub-housing 12 can be a hollow structure with one end open, and the first sub-housing 11 can be a plate-like structure, with the first sub-housing 11 covering the open side of the second sub-housing 12, so that the first sub-housing 11 and the second sub-housing 12 jointly define a storage space; the first sub-housing 11 and the second sub-housing 12 can also be hollow structures with one end open, with the open side of the first sub-housing 11 covering the open side of the second sub-housing 12.

[0119] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0120] The battery cell 20 may be a secondary battery or a primary battery; the battery cell 20 may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto.

[0121] Please refer to Figure 3, which is an exploded view of a battery cell provided in some embodiments of the present application. As shown in Figure 3, a battery cell 20 includes a housing 21, an electrode assembly 22, and other functional components. Housing 21 includes a shell 211 and an end cap 212. Shell 211 has an opening, and end cap 212 closes the opening, isolating the internal environment of battery cell 20 from the external environment.

[0122] The housing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. The housing 211 can be of various shapes and sizes. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 22. The housing 211 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0123] The end cap 212 refers to a component that covers the opening of the shell 211 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 212 can be adapted to the shape of the shell 211 to match the shell 211. Optionally, the end cap 212 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 212 is not easily deformed when squeezed or collided, so that the battery cell 20 can have a higher structural strength and the reliability can also be improved. Functional components such as electrode terminals 23 can be provided on the end cap 212. The electrode terminal 23 can be used to electrically connect to the electrode assembly 22 for outputting or inputting electrical energy of the battery cell 20. The material of the end cap 212 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this. In some embodiments, an insulating structure may be provided inside the end cap 212 to isolate the electrical connection components in the housing 211 from the end cap 212 to reduce the risk of short circuits. For example, the insulating structure may be made of plastic, rubber, or the like.

[0124] The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 22 may be contained in the housing 211. The electrode assembly 22 is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The separator is used to separate the positive electrode sheet and the negative electrode sheet to avoid internal short circuits between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute a tab. The positive tab and the negative tab may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab is connected to the electrode terminal 23 through the adapter 24 to form a current loop.

[0125] Please refer to Figures 4 and 5. Figure 4 is a schematic diagram of the structure of the electrode assembly provided in some embodiments of the present application, and Figure 5 is a cross-sectional view of the electrode assembly provided in some embodiments of the present application. According to some embodiments of the present application, the embodiments of the present application provide a battery cell 20, and the battery cell 20 includes an electrode assembly 22. The electrode assembly 22 includes a positive electrode sheet 221 and a negative electrode sheet 222. The positive electrode sheet 221 includes a first edge 221a in a first direction X, and the negative electrode sheet 222 includes a second edge 222a corresponding to the first edge 221a. Along the first direction X, the first edge 221a exceeds the second edge 222a.

[0126] In the figure, the direction indicated by the letter X can be a first direction. The first direction X can be a width direction of the electrode assembly 22 or a length direction of the electrode assembly 22. The first direction X intersects with the thickness direction of the electrode assembly 22.

[0127] Optionally, the first direction X may be perpendicular to the thickness direction of the electrode assembly 22 .

[0128] Observing along the thickness direction of the electrode assembly 22 , in the first direction X, the first edge 221 a exceeds the second edge 222 a , and the orthographic projection of the second edge 222 a falls within the orthographic projection of the positive electrode sheet 221 .

[0129] The first edge 221a may be the edge of the positive electrode current collector or the edge of the positive electrode active material layer. For example, when the positive electrode active material layer extends to the edge of the positive electrode current collector, the first edge 221a is the edge of the positive electrode active material layer.

[0130] The second edge 222a may be the edge of the negative electrode current collector or the edge of the negative electrode active material layer. Alternatively, the negative electrode active material layer may extend to the edge of the negative electrode current collector.

[0131] The electrode assembly 22 further includes a separator 220 , which is disposed between the positive electrode sheet 221 and the negative electrode sheet 222 to insulate and isolate the positive electrode sheet 221 from the negative electrode sheet 222 .

[0132] According to the electrode assembly 22 of the embodiment of the present application, the first edge 221a of the positive electrode sheet 221 exceeds the second edge 222a of the negative electrode sheet 222, which can reduce the impact of the edge of the positive electrode sheet 221 on the extrusion and shearing of the negative electrode sheet 222 during the charge and discharge cycle of the battery cell 20, reduce the probability of the negative electrode sheet 222 being sheared and broken, and thus improve the reliability of the battery cell 20 composed of the electrode assembly 22.

[0133] 5 , according to some embodiments of the present application, the thickness of the negative electrode sheet 222 is H1 , and the thickness of the positive electrode sheet 221 is H2 , satisfying H1 < H2 .

[0134] The thickness direction of the negative electrode sheet 222 is parallel to the thickness direction of the positive electrode sheet 221 .

[0135] In the above solution, the thickness of the negative electrode sheet 222 is smaller than that of the positive electrode sheet 221, and the first edge 221a of the positive electrode sheet 221 exceeds the second edge 222a of the negative electrode sheet 222, which can reduce the risk of the negative electrode sheet 222 being sheared and broken by the positive electrode sheet 221.

[0136] According to some embodiments of the present application, the thickness of the negative electrode sheet 222 is H1, which satisfies 5 μm≤H1≤100 μm.

[0137] Optionally, H1 may be, but is not limited to, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc. H may be any value between 5 μm and 10 μm.

[0138] In the above solution, the thickness of the negative electrode plate 222 satisfies the above relationship, the processing and manufacturing difficulty is low, and the negative electrode plate 222 has high strength.

[0139] According to some embodiments of the present application, 10 μm≤H1≤80 μm.

[0140] Alternatively, H1 may be, but is not limited to, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, etc.

[0141] In the above solution, the negative electrode sheet 222 has a higher strength, or can be provided with more active materials.

[0142] Please refer to Figure 4. According to some embodiments of the present application, the positive electrode sheet 221 includes a positive electrode current collector 2211 and a positive electrode active material layer 2212. The positive electrode active material layer 2212 is arranged on the surface of the positive electrode current collector 2211. The positive electrode current collector 2211 has a first edge 221a. The positive electrode sheet 221 also includes a positive electrode tab 2213. The positive electrode tab 2213 extends from the first edge 221a.

[0143] The positive electrode active material layer 2212 is coated on the surface of the positive electrode current collector 2211 . The positive electrode active material layer 2212 can be coated on the surface of one side of the positive electrode current collector 2211 or on the surfaces of both sides of the positive electrode current collector 2211 .

[0144] The positive electrode sheet 221 includes a first main portion 2214 and a positive electrode tab 2213. The positive electrode tab 2213 extends from the edge of the first main portion 2214. The first edge 221a can be the edge of the first main portion 2214 extending from the tab. The positive electrode active material layer 2212 can extend to the first edge 221a, or the positive electrode active material layer 2212 does not extend to the first edge 221a, so that the positive electrode current collector 2211 constituting the first main portion 2214 has a hollow foil area.

[0145] In the above solution, the first edge 221 a is an edge extending from the positive electrode tab 2213 , so as to facilitate electrical connection between the positive electrode tab 2213 and the positive electrode terminal.

[0146] During the manufacturing process of the positive electrode sheet 221, to reserve a position for cutting the positive electrode tab 2213, the positive electrode active material layer 2212 is coated on the surface of the positive current collector 2211 without extending to the first edge 221a of the positive current collector 2211, thereby allowing the positive electrode tab 2213 to extend from the first edge 221a. In this case, the positive electrode active material layer 2212 can extend beyond the second edge 222a along the first direction X to reduce the impact of the positive electrode active material layer 2212 edge on the compression and shearing of the negative electrode sheet 222. Alternatively, the second edge 222a can extend beyond the positive electrode active material layer 2212 along the first direction X to reduce the risk of metal ions precipitating on the surface of the negative current collector and puncturing the separator 220, resulting in a short circuit between the positive and negative electrodes.

[0147] Please refer to Figure 6, which is a schematic diagram of the assembly of the first insulating member and the positive electrode sheet provided in some embodiments of the present application. According to some embodiments of the present application, along the first direction X, the second edge 222a extends beyond the positive electrode active material layer 2212, the positive electrode current collector 2211 has a first hollow foil area 2215, and the first hollow foil area 2215 is located between the first edge 221a and the positive electrode active material layer 2212. The electrode assembly 22 also includes a first insulating member 223, which covers the first hollow foil area 2215. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the second edge 222a falls within the orthographic projection of the first insulating member 223.

[0148] In the figure, the direction indicated by the letter Z may be the thickness direction of the positive electrode sheet.

[0149] The second edge 222 a extends beyond the positive electrode active material layer 2212 , so that the positive electrode sheet 221 has a first hollow foil area 2215 formed near the first edge 221 a . The first hollow foil area 2215 is located between the first edge 221 a and the positive electrode active material layer 2212 .

[0150] The first insulating member 223 is an insulating component capable of insulating and isolating the positive electrode fluid and the negative electrode plate 222 .

[0151] The first insulating member 223 has a certain thickness. When the first insulating member 223 is disposed in the first hollow foil region 2215, the first insulating member 223 covers the surface of the positive electrode current collector 2211. The first insulating member 223 contacts the edge of the positive electrode active material layer 2212, thereby reducing the height of the step of the positive electrode sheet 221 at the first hollow foil region 2215. The step is formed by the edge of the positive electrode active material layer 2212. For example, in the thickness direction Z of the positive electrode sheet, the step is formed by the thickness variation region of the positive electrode sheet.

[0152] On the same side of the positive electrode current collector 2211 , the thickness of the first insulating member 223 may be the same as or different from the thickness of the positive electrode active material layer 2212 .

[0153] When the electrode assembly 22 has a laminated structure, the thickness direction Z of the positive electrode sheet can be parallel to the thickness direction of the electrode assembly 22. When the electrode assembly 22 has a wound structure, the electrode assembly 22 includes a straight region and a corner region. In the straight region, the thickness direction Z of the positive electrode sheet is parallel to the thickness direction of the electrode assembly 22; in the corner region, the thickness direction Z of the positive electrode sheet intersects with the thickness direction of the electrode assembly 22.

[0154] In the above scheme, along the first direction X, the second edge 222a of the negative electrode sheet 222 exceeds the positive electrode active material layer 2212, and the first insulating member 223 is set in the first empty foil area 2215, so that the height of the step of the positive electrode sheet 221 near the edge of the positive electrode active material layer 2212 is relatively low. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the second edge 222a falls within the orthographic projection of the first insulating member 223, which can reduce the impact of the step on the positive electrode sheet 221 on the extrusion and shearing of the negative electrode sheet 222 during the charge and discharge cycle of the battery cell 20, and effectively reduce the probability of the negative electrode sheet 222 being sheared and broken.

[0155] 6 , according to some embodiments of the present application, along the thickness direction Z of the positive electrode sheet, the surface of the first insulating member 223 facing away from the positive current collector 2211 does not exceed the surface of the positive active material layer 2212 facing away from the positive current collector 2211 .

[0156] On the same side of the positive electrode current collector 2211, the surface of the first insulating member 223 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, so that the thickness of the first insulating member 223 is less than or equal to the thickness of the positive electrode active material layer 2212, which can reduce the assembly space occupied by the first insulating member 223 and reduce the impact on the energy density of the battery cell 20.

[0157] In the above scheme, the surface of the first insulating member 223 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, and can achieve a height transition from the positive electrode active material layer 2212 to the first insulating member 223 in the first direction X, so as to reduce the height difference of the positive electrode plate 221 near the first edge 221a, and can reduce the shear effect of the edge of the positive electrode active material layer 2212 on the negative electrode plate 222, so as to reduce the risk of the negative electrode plate 222 being sheared and broken during the charge and discharge cycle of the battery cell 20.

[0158] In some embodiments, one end of the first insulating member 223 is connected to the positive electrode active material layer 2212, and the first insulating member 223 is in contact with the positive electrode active material layer 2212, so that the positive electrode active material layer 2212 transitions smoothly to the first insulating member 223, thereby reducing the extrusion and shearing of the edge of the positive electrode active material layer 2212 on the negative electrode plate 222 when the positive electrode plate 221 expands.

[0159] According to some embodiments of the present application, the first insulating member 223 is an insulating coating or an insulating adhesive layer.

[0160] In the above solution, when assembling the first insulating member 223 and the positive electrode sheet 221, an insulating coating is sprayed onto the surface of the positive electrode current collector 2211. After drying and solidifying, the insulating coating forms the first insulating member 223, facilitating ease of handling. Alternatively, the first insulating member 223 can be an insulating adhesive layer adhered to the surface of the positive electrode current collector 2211, which is simple to handle and requires minimal manufacturing effort.

[0161] Please refer to Figure 6. According to some embodiments of the present application, the positive electrode plate 221 further has a third edge 221b, which is arranged opposite to the first edge 221a along the first direction X. The negative electrode plate 222 further has a fourth edge 222b corresponding to the third edge 221b, which is arranged opposite to the second edge 222a along the first direction X. Along the first direction X, the third edge 221b exceeds the fourth edge 222b.

[0162] The third edge 221 b may be an edge of the first body portion 2214 in the first direction X away from the first edge 221 a .

[0163] The fourth edge 222 b is the fourth edge 222 b of the negative electrode plate 222 corresponding to the third edge 221 b . The fourth edge 222 b is closer to the third edge 221 b than other edges of the negative electrode plate 222 .

[0164] Along the first direction X, the third edge 221 b exceeds the fourth edge 222 b , so that both ends of the positive electrode sheet 221 in the first direction X exceed the edge of the negative electrode sheet 222 .

[0165] In the above solution, the third edge 221b exceeds the fourth edge 222b, which can reduce the impact of the edge of the positive electrode sheet 221 on the negative electrode sheet 222 at the end away from the first edge 221a in the first direction X, and further reduce the probability of the negative electrode sheet 222 being sheared and broken.

[0166] Please refer to Figure 7, which is a schematic diagram of the assembly of a second insulating member and a positive electrode sheet according to some embodiments of the present application. According to some embodiments of the present application, the positive electrode sheet 221 includes a positive current collector 2211 and a positive active material layer 2212. The positive active material layer 2212 is disposed on the surface of the positive current collector 2211. Along the first direction X, the fourth edge 222b extends beyond the positive active material layer 2212. The positive current collector 2211 has a second hollow foil region 2216, which is located between the third edge 221b and the positive active material layer 2212. The electrode assembly 22 also includes a second insulating member 224, which covers the second hollow foil region 2216. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the fourth edge 222b falls within the orthographic projection of the second insulating member 224.

[0167] The second empty foil area 2216 is an area of ​​the positive electrode current collector 2211 near the third edge 221b that is not coated with the positive electrode active material layer 2212. Along the first direction X, the second empty foil area 2216 is located between the third edge 221b and the positive electrode active material layer 2212.

[0168] The second insulating member 224 is an insulating component capable of insulating and isolating the positive electrode current collector 2211 and the negative electrode plate 222 .

[0169] The second insulating member 224 has a certain thickness. When the second insulating member 224 is disposed in the second hollow foil region 2216, the second insulating member 224 covers the surface of the positive electrode current collector 2211. The second insulating member 224 contacts the edge of the positive electrode active material layer 2212, thereby reducing the height of the step of the positive electrode tab 221 at the second hollow foil region 2216. On the same side of the positive electrode current collector 2211, the thickness of the second insulating member 224 can be the same as or different from the thickness of the positive electrode active material layer 2212.

[0170] In the above scheme, along the first direction X, the fourth edge 222b exceeds the positive electrode active material layer 2212, the second insulating member 224 is arranged in the second empty foil area 2216, and along the thickness direction Z of the positive electrode sheet, the orthographic projection of the fourth edge 222b falls within the orthographic projection of the second insulating member 224, so that at the end of the positive electrode sheet 221 close to the third edge 221b, the height of the step near the edge of the positive electrode active material layer 2212 is relatively low, which can reduce the effect of the step on the positive electrode sheet 221 on the extrusion and shearing of the negative electrode sheet 222 during the charge and discharge cycle of the battery cell 20, thereby reducing the probability of the negative electrode sheet 222 being sheared and broken.

[0171] 7 , according to some embodiments of the present application, along the thickness direction Z of the positive electrode sheet, the surface of the second insulating member 224 facing away from the positive current collector 2211 does not exceed the surface of the positive active material layer 2212 facing away from the positive current collector 2211 .

[0172] On the same side of the positive electrode current collector 2211, the surface of the second insulating member 224 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, so that the thickness of the second insulating member 224 is less than or equal to the thickness of the positive electrode active material layer 2212, which can reduce the assembly space occupied by the second insulating member 224 and reduce the impact on the energy density of the battery cell 20.

[0173] In the above scheme, the surface of the second insulating member 224 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, and can achieve a height transition from the positive electrode active material layer 2212 to the second insulating member 224 in the first direction X, so as to reduce the height difference of the positive electrode plate 221 at the edge of the positive electrode active material layer 2212, so as to reduce the risk of the negative electrode plate 222 being sheared and broken during the charge and discharge cycle of the battery cell 20.

[0174] In some embodiments, one end of the second insulating member 224 is connected to the positive electrode active material layer 2212, and the second insulating member 224 is in contact with the positive electrode active material layer 2212, so that the positive electrode active material layer 2212 transitions smoothly to the second insulating member 224, thereby reducing the extrusion and shearing of the edge of the positive electrode active material layer 2212 on the negative electrode plate 222 when the positive electrode plate 221 expands.

[0175] According to some embodiments of the present application, the second insulating member 224 is an insulating coating applied to the positive electrode current collector 2211 , or the second insulating member 224 is an insulating adhesive layer applied to the positive electrode current collector 2211 .

[0176] In the above solution, when assembling the second insulating member 224 and the positive electrode sheet 221, an insulating coating is sprayed onto the surface of the positive electrode current collector 2211. After drying and solidifying, the insulating coating forms the second insulating member 224, facilitating handling. Alternatively, the second insulating member 224 can be an insulating adhesive layer adhered to the surface of the positive electrode current collector 2211, which is simple to handle and requires minimal manufacturing effort.

[0177] In some embodiments, the material of the second insulating member 224 can be the same as that of the first insulating member 223 to reduce manufacturing costs.

[0178] 6 , according to some embodiments of the present application, the positive electrode sheet 221 includes a positive electrode current collector 2211 and a positive electrode active material layer 2212 . The positive electrode active material layer 2212 is disposed on the surface of the positive electrode current collector 2211 . Along the first direction X, the positive electrode active material layer 2212 extends to the third edge 221 b .

[0179] When the positive electrode active material layer 2212 extends to the third edge 221 b , the edge of the positive electrode active material layer 2212 and the third edge 221 b together constitute the edge of the positive electrode sheet 221 .

[0180] When the positive electrode active material layer is coated on the positive electrode current collector, the positive electrode active material layer 2212 extends to the third edge 221 b , which facilitates coating of the positive electrode active material layer 2212 and processing and manufacturing of the positive electrode sheet 221 .

[0181] In some embodiments, when the battery cell 20 is a metal battery, the negative electrode tab 222 includes a negative current collector 2221 and a metal layer 2222. Along the thickness direction Z of the positive electrode tab, the orthographic projection of the fourth edge 222b can fall within the orthographic projection of the positive active material layer. Due to the characteristics of metal batteries, metal ions can migrate between the negative current collector and the positive electrode tab during the charge and discharge cycles of the battery cell 20.

[0182] In the above scheme, the positive electrode active material layer 2212 extends to the third edge 221b, which can eliminate the step of the positive electrode plate 221 at one end close to the third edge 221b, reduce the risk of the edge of the positive electrode active material layer 2212 squeezing and shearing the negative electrode plate 222, and reduce the risk of the negative electrode plate 222 being sheared and broken during the charge and discharge cycle of the battery cell 20.

[0183] Please refer to Figures 8 and 9. Figure 8 is a schematic diagram of the assembly of the third insulating member and the positive electrode sheet according to some embodiments of the present application, and Figure 9 is a partial enlarged view of point A in Figure 8. According to some embodiments of the present application, the electrode assembly 22 further includes a third insulating member 225, and a portion of the third insulating member 225 is disposed on the portion of the positive active material layer 2212 that extends beyond the fourth edge 222b.

[0184] In the above solution, part of the third insulating member 225 is disposed on the portion of the positive active material layer 2212 that extends beyond the fourth edge 222 b , which can reduce the risk of metal ions precipitating on the surface of the negative electrode sheet 222 and causing a short circuit between the positive and negative electrodes.

[0185] According to some embodiments of the present application, along the thickness direction Z of the positive electrode sheet, the orthographic projection of the fourth edge 222 b falls within the orthographic projection of the third insulating member 225 , and the thickness of the third insulating member 225 is less than the thickness of the positive active material layer 2212 .

[0186] Observed along the thickness direction Z of the positive electrode tab, the third insulating member 225 partially overlaps the negative electrode tab 222 , so that the orthographic projection of the fourth edge 222 b of the negative electrode tab 222 falls within the orthographic projection of the third insulating member 225 .

[0187] In the above scheme, the thickness of the third insulating member 225 is less than the thickness of the positive electrode active material layer 2212, and the height difference between the third insulating member 225 and the positive electrode active material layer 2212 is small, which can reduce the shear effect on the negative electrode plate 222, and the third insulating member 225 occupies a smaller assembly space; at the same time, the orthographic projection of the fourth edge 222b falls within the orthographic projection of the third insulating member 225, which can reduce the risk of metal ions precipitating on the surface of the negative electrode current collector and damaging the isolation membrane 220, and reduce the risk of short circuit between the positive and negative electrodes.

[0188] According to some embodiments of the present application, the third insulating member 225 is an insulating coating or an insulating adhesive layer.

[0189] In the above embodiment, when the third insulating member 225 is assembled with the positive electrode sheet 221, an insulating coating is sprayed onto the surface of the positive electrode active material layer 2212. After the insulating coating dries and solidifies, the third insulating member 225 is formed, which facilitates handling. Alternatively, the third insulating member 225 can be an insulating adhesive layer adhered to the surface of the positive electrode active material layer 2212, which is simple to handle and has low processing difficulty.

[0190] In some embodiments, the material of the third insulating member 225 can be the same as that of the first insulating member 223 to reduce manufacturing costs.

[0191] Please refer to Figure 10, which is a cross-sectional view of an electrode assembly provided in some other embodiments of the present application. According to some embodiments of the present application, the positive electrode tab 221 further has a third edge 221b, a fifth edge 221c, and a sixth edge 221d. The third edge 221b is arranged opposite to the first edge 221a along the first direction X, and the third edge 221b is arranged opposite to the first edge 221a along the first direction X. The fifth edge 221c connects the first end of the first edge 221a and the first end of the third edge 221b. The sixth edge 221d connects the second end of the first edge 221a and the second end of the third edge 221b. The negative electrode tab 222 further has a seventh edge 222c corresponding to the fifth edge 221c and an eighth edge 222d corresponding to the sixth edge 221d. Along the second direction Y, the fifth edge 221c extends beyond the seventh edge 222c, and / or the sixth edge 221d extends beyond the eighth edge 222d. The second direction Y is perpendicular to the first direction X.

[0192] In the figure, the direction indicated by the letter Y may be the second direction. The second direction Y may be the length direction of the electrode assembly 22 or the width direction of the electrode assembly 22.

[0193] The first end and the second end of the first edge 221 a are two opposite ends of the first edge 221 a ; the first end and the second end of the third edge 221 b are two opposite ends of the third edge 221 b .

[0194] In some embodiments, the electrode assembly 22 may be a laminated structure.

[0195] In some embodiments, the electrode assembly 22 may be a wound structure, and the second direction Y may be the length direction of the electrode sheet when the electrode sheet is unfolded.

[0196] The electrode assembly 22 is a laminated structure, with a plurality of positive electrode sheets 221 and a plurality of negative electrode sheets 222 being alternately stacked, and an isolation film 220 is provided between adjacent positive electrode sheets 221 and negative electrode sheets 222 .

[0197] In some embodiments, the first direction X may be the length direction of the positive electrode sheet 221, and the second direction Y may be the width direction of the positive electrode sheet 221. Alternatively, the first direction X may be the width direction of the positive electrode sheet 221, and the second direction Y may be the length direction of the positive electrode sheet 221.

[0198] The fifth edge 221 c and the sixth edge 221 d are two edges of the positive electrode sheet 221 that are opposite to each other in the second direction Y. The fifth edge 221 c and the sixth edge 221 d are located at opposite ends of the positive electrode sheet 221 .

[0199] The seventh edge 222c and the eighth edge 222d are two edges of the negative electrode plate 222 that are oppositely arranged in the second direction Y. The seventh edge 222c is closer to the fifth edge 221c than the eighth edge 222d, and the eighth edge 222d is closer to the sixth edge 221d than the seventh edge 222c.

[0200] In the above scheme, the fifth edge 221c exceeds the seventh edge 222c, and / or the sixth edge 221d exceeds the eighth edge 222d, further reducing the impact of the edge of the positive electrode sheet 221 on the extrusion and shearing of the negative electrode sheet 222 during the charge and discharge cycle of the battery cell 20, reducing the probability of the negative electrode sheet 222 being sheared and broken, thereby improving the reliability of the battery cell 20 composed of the electrode assembly 22.

[0201] Please refer to Figure 10. According to some embodiments of the present application, the positive electrode sheet 221 includes a positive electrode current collector 2211 and a positive electrode active material layer 2212. The positive electrode active material layer 2212 is arranged on the surface of the positive electrode current collector 2211. Along the second direction Y, the positive electrode active material layer 2212 extends to the fifth edge 221c, and / or, the positive electrode active material layer 2212 extends to the sixth edge 221d.

[0202] When the positive electrode active material layer 2212 extends to the fifth edge 221c, the edge of the positive electrode active material layer 2212 and the fifth edge 221c together constitute the edge of one end of the positive electrode plate 221 in the second direction Y; when the positive electrode active material layer 2212 extends to the sixth edge 221d, the edge of the positive electrode active material layer 2212 and the sixth edge 221d together constitute the edge of the other end of the positive electrode plate 221 in the second direction Y.

[0203] The positive electrode active material layer 2212 extends to the fifth edge 221 c and / or the sixth edge 221 d , which facilitates coating of the positive electrode active material layer 2212 and processing and manufacturing of the positive electrode sheet 221 .

[0204] In the above scheme, the positive electrode active material layer 2212 extends to the fifth edge 221c and / or the sixth edge 221d, which can eliminate the steps at both ends of the positive electrode plate 221 in the second direction Y, further reduce the risk of the edge of the positive electrode active material layer 2212 squeezing and shearing the negative electrode plate 222, and reduce the risk of the negative electrode plate 222 being sheared and broken during the charge and discharge cycle of the battery cell 20.

[0205] Please refer to Figure 11, which is a schematic diagram of the assembly of the fourth and fifth insulating members with the positive electrode sheet according to some embodiments of the present application. According to some embodiments of the present application, the electrode assembly 22 further includes a fourth insulating member 226, a portion of which is disposed on a portion of the positive active material layer 2212 that extends beyond the seventh edge 222c, the thickness of the fourth insulating member 226 being less than the thickness of the positive active material layer 2212, and the orthographic projection of the seventh edge 222c along the thickness direction Z of the positive electrode sheet falling within the orthographic projection of the fourth insulating member 226; and / or the electrode assembly 22 further includes a fifth insulating member 227, a portion of which is disposed on a portion of the positive active material layer 2212 that extends beyond the eighth edge 222d, the thickness of the fifth insulating member 227 being less than the thickness of the positive active material layer 2212, and the orthographic projection of the eighth edge 222d along the thickness direction Z of the positive electrode sheet falling within the orthographic projection of the fifth insulating member 227.

[0206] When observed along the thickness direction Z of the positive electrode sheet, the fourth insulating member 226 partially overlaps with the negative electrode sheet 222, so that the orthographic projection of the seventh edge 222c of the negative electrode sheet 222 falls within the orthographic projection of the fourth insulating member 226; when observed along the thickness direction Z of the positive electrode sheet, the fifth insulating member 227 partially overlaps with the negative electrode sheet 222, so that the orthographic projection of the eighth edge 222d falls within the orthographic projection of the fifth insulating member 227.

[0207] In the above embodiment, the thickness of the fourth insulating member 226 is less than that of the positive electrode active material layer 2212, and the height difference between the fourth insulating member 226 and the positive electrode active material layer 2212 is small. Furthermore, the thickness of the fifth insulating member 227 is less than that of the positive electrode active material layer 2212, and the height difference between the fifth insulating member 227 and the positive electrode active material layer 2212 is small. This can reduce the shearing effect on the negative electrode tab 222 and the risk of shear fracture of the negative electrode tab 222. Furthermore, the fourth and fifth insulating members 226 and 227 occupy a small assembly space. Furthermore, the orthographic projection of the seventh edge 222c falls within the orthographic projection of the fourth insulating member 226, and / or the orthographic projection of the eighth edge 222d falls within the orthographic projection of the fifth insulating member 227. This can reduce the risk of metal ions precipitating on the surface of the negative electrode current collector and damaging the separator 220, thereby reducing the risk of positive-negative electrode short circuit.

[0208] According to some embodiments of the present application, the fourth insulating member 226 is an insulating coating or an insulating adhesive layer; and / or the fifth insulating member 227 is an insulating coating or an insulating adhesive layer.

[0209] In the above embodiment, when the fourth insulating member 226 and / or the fifth insulating member 227 are assembled with the positive electrode sheet 221, an insulating coating is sprayed onto the surface of the positive electrode active material layer 2212. After the insulating coating dries and solidifies, the fourth insulating member 226 and / or the fifth insulating member 227 are formed, which facilitates handling. Alternatively, the fourth insulating member 226 and / or the fifth insulating member 227 can be an insulating adhesive layer adhered to the surface of the positive electrode active material layer 2212, which is simple to handle and has low processing difficulty.

[0210] In some embodiments, the material of the fourth insulating member 226 and the fifth insulating member 227 may be the same as that of the first insulating member 223 to reduce manufacturing costs.

[0211] Please refer to Figure 12, which is a schematic diagram of the assembly of the sixth insulating member and the seventh insulating member with the positive electrode sheet provided in some embodiments of the present application. According to some embodiments of the present application, along the second direction Y, the seventh edge 222c exceeds the positive electrode active material layer 2212, the positive electrode current collector 2211 has a third empty foil area 2217, and the third empty foil area 2217 is located between the fifth edge 221c and the positive electrode active material layer 2212. The electrode assembly 22 also includes a sixth insulating member 228, which covers the third empty foil area 2217. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the seventh edge 222c falls on the positive projection of the sixth insulating member 228. projection; and / or, along the second direction Y, the eighth edge 222d exceeds the positive electrode active material layer 2212, the positive electrode current collector 2211 has a fourth empty foil area 2218, the fourth empty foil area 2218 is located between the sixth edge 221d and the positive electrode active material layer 2212, the electrode assembly 22 also includes a seventh insulating member 229, the seventh insulating member 229 covers the fourth empty foil area 2218, along the thickness direction Z of the positive electrode sheet, the orthographic projection of the eighth edge 222d falls within the orthographic projection of the seventh insulating member 229.

[0212] The third hollow foil area 2217 is an area of ​​the positive electrode current collector 2211 near the fifth edge 221c that is not coated with the positive electrode active material layer 2212. Along the second direction Y, the third hollow foil area 2217 is located between the fifth edge 221c and the positive electrode active material layer 2212.

[0213] The sixth insulating member 228 is an insulating component capable of insulating and isolating the positive electrode current collector 2211 and the negative electrode plate 222 .

[0214] The sixth insulating member 228 has a certain thickness. When the sixth insulating member 228 is disposed in the third hollow foil region 2217, the sixth insulating member 228 covers the surface of the positive electrode current collector 2211. The sixth insulating member 228 contacts the edge of the positive electrode active material layer 2212, thereby reducing the height of the step of the positive electrode tab 221 at the third hollow foil region 2217. On the same side of the positive electrode current collector 2211, the thickness of the sixth insulating member 228 can be the same as or different from the thickness of the positive electrode active material layer 2212.

[0215] The fourth empty foil area 2218 is an area of ​​the positive electrode current collector 2211 near the sixth edge 221d that is not coated with the positive electrode active material layer 2212. Along the second direction Y, the fourth empty foil area 2218 is located between the sixth edge 221d and the positive electrode active material layer 2212.

[0216] The seventh insulating member 229 is an insulating component capable of insulating and isolating the positive electrode current collector 2211 and the negative electrode plate 222 .

[0217] The seventh insulating member 229 has a certain thickness. When the seventh insulating member 229 is disposed in the fourth hollow foil region 2218, the seventh insulating member 229 covers the surface of the positive electrode current collector 2211. The seventh insulating member 229 contacts the edge of the positive electrode active material layer 2212, thereby reducing the height of the step of the positive electrode tab 221 at the fourth hollow foil region 2218. On the same side of the positive electrode current collector 2211, the thickness of the seventh insulating member 229 can be the same as or different from the thickness of the positive electrode active material layer 2212.

[0218] In the above scheme, along the second direction Y, the seventh edge 222c exceeds the positive electrode active material layer 2212, and the sixth insulating member 228 is arranged in the third empty foil area 2217. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the seventh edge 222c falls within the orthographic projection of the sixth insulating member 228, so that at the end of the positive electrode sheet 221 close to the fifth edge 221c, the height of the step near the edge of the positive electrode active material layer 2212 is relatively low, which can reduce the effect of the step on the positive electrode sheet 221 on the extrusion and shearing of the negative electrode sheet 222 during the charge and discharge cycle of the battery cell 20, thereby reducing the probability of the negative electrode sheet being sheared and broken. Along the second direction Y, the eighth edge 222d exceeds the positive electrode active material layer 2212, and the seventh insulating member 229 is arranged in the fourth empty foil area 2218. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the eighth edge 222d falls within the orthographic projection of the seventh insulating member 229, so that at the end of the positive electrode sheet 221 close to the sixth edge 221d, the height of the step near the edge of the positive electrode active material layer 2212 is relatively low, which can reduce the effect of the step on the positive electrode sheet 221 on the extrusion and shearing of the negative electrode sheet 222 during the charge and discharge cycle of the battery cell 20, thereby reducing the probability of the negative electrode sheet being sheared and broken.

[0219] According to some embodiments of the present application, along the thickness direction Z of the positive electrode sheet, the surface of the sixth insulating member 228 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, and / or, the surface of the seventh insulating member 229 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211.

[0220] On the same side of the positive electrode current collector 2211, the surface of the sixth insulating member 228 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, so that the thickness of the sixth insulating member 228 is less than or equal to the thickness of the positive electrode active material layer 2212, which can reduce the assembly space occupied by the sixth insulating member 228 and reduce the impact on the energy density of the battery cell 20.

[0221] On the same side of the positive electrode current collector 2211, the surface of the seventh insulating member 229 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, so that the thickness of the seventh insulating member 229 is less than or equal to the thickness of the positive electrode active material layer 2212, which can reduce the assembly space occupied by the seventh insulating member 229 and reduce the impact on the energy density of the battery cell 20.

[0222] In the above scheme, the surface of the sixth insulating member 228 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, and can realize the height transition from the positive electrode active material layer 2212 to the sixth insulating member 228 in the second direction Y; the surface of the seventh insulating member 229 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, and can realize the height transition from the positive electrode active material layer 2212 to the seventh insulating member 229 in the second direction Y, so as to reduce the height difference of the positive electrode plate 221 at the edge of the positive electrode active material layer 2212, so as to reduce the risk of the negative electrode plate 222 being sheared and broken during the charge and discharge cycle of the battery cell 20.

[0223] In some embodiments, one end of the sixth insulating member 228 is connected to the positive electrode active material layer 2212, and the sixth insulating member 228 is bonded to the positive electrode active material layer 2212, so that the positive electrode active material layer 2212 to the sixth insulating member 228 transitions smoothly; one end of the seventh insulating member 229 is connected to the positive electrode active material layer 2212, and the seventh insulating member 229 is bonded to the positive electrode active material layer 2212, so that the positive electrode active material layer 2212 to the seventh insulating member 229 transitions smoothly, reducing the extrusion and shearing of the edge of the positive electrode active material layer 2212 on the negative electrode sheet 222 when the positive electrode sheet 221 expands.

[0224] According to some embodiments of the present application, the sixth insulating member 228 and the seventh insulating member 229 are both insulating coatings applied to the positive electrode current collector 2211 , or the sixth insulating member 228 and the seventh insulating member 229 are both insulating adhesive layers applied to the positive electrode current collector 2211 .

[0225] In the above embodiment, when the sixth and seventh insulating members 228 and 229 are assembled with the positive electrode sheet 221, an insulating coating is sprayed onto the surface of the positive electrode current collector 2211. After drying and solidifying, the insulating coating forms the sixth and seventh insulating members 228 and 229, facilitating ease of handling. Alternatively, the sixth and seventh insulating members 228 and 229 can be insulating adhesive layers adhered to the surface of the positive electrode current collector 2211, simplifying handling and reducing manufacturing complexity.

[0226] In some embodiments, the material of the sixth insulating member 228 and the seventh insulating member 229 may be the same as that of the first insulating member 223 to reduce manufacturing costs.

[0227] According to some embodiments of the present application, the negative electrode plate 222 includes a negative electrode current collector 2221 and a metal layer 2222 , and the metal layer 2222 is disposed on the surface of the negative electrode current collector 2221 .

[0228] The metal layer 2222 is coated on the surface of the negative electrode current collector 2221 to form the negative electrode plate 222 .

[0229] The negative electrode sheet 222 may include a second main portion 2224 and a negative electrode tab 2223 extending from an edge of the second main portion 2224. The edge of the second main portion 2224 from which the negative electrode tab 2223 extends may be a second edge 222a. The metal layer 2222 may completely cover the negative electrode current collector 2221 constituting the second main portion 2224, thereby enabling the battery cell 20 formed by the negative electrode sheet 222 to have a higher energy density. In some embodiments, the second edge 222a and the fourth edge 222b may be two opposing edges of the second main portion 2224 in the first direction X. The negative electrode tab 2223 may extend from the second edge 222a, or the negative electrode tab 2223 may extend from the fourth edge 222b.

[0230] In the above solution, the metal layer 2222 has a relatively thin thickness. When the first edge 221a exceeds the second edge 222a, the risk of the negative electrode sheet 222 being sheared and broken due to the squeezing and shearing of the negative electrode sheet 2221 and the metal layer 2222 by the positive electrode sheet 221 can be reduced, thereby improving the reliability of the battery cell 20.

[0231] According to some embodiments of the present application, the negative electrode current collector 2221 is a copper foil, and the metal layer 2222 is a lithium metal layer; or, the negative electrode current collector 2221 is an aluminum foil or a copper foil, and the metal layer 2222 is a sodium metal layer.

[0232] In the above solution, the metal layer 2222 is a lithium metal layer or a sodium metal layer, which can enable the battery cell 20 to have a higher mass energy density and volume energy density.

[0233] In some embodiments, when the negative electrode sheet 222 includes a negative electrode current collector 2221 and a metal layer 2222 , the battery cell 20 formed by the electrode assembly 22 provided in the above embodiment is a metal battery cell.

[0234] According to some embodiments of the present application, the negative electrode plate 222 includes a negative electrode current collector 2221 , and no active material layer is provided on the surface of the negative electrode current collector 2221 .

[0235] In the above solution, no active material layer is provided on the surface of the negative electrode current collector 2221 , which can reduce materials and lower costs.

[0236] According to some embodiments of the present application, the thickness of the negative electrode current collector 2221 may be 5 μm to 6 μm.

[0237] Optionally, the thickness of the negative electrode current collector 2221 may be 5 μm.

[0238] According to some embodiments of the present application, the thickness of the metal layer 2222 disposed on one side of the negative electrode current collector 2221 may be 10 μm to 45 μm.

[0239] Optionally, the thickness of the metal layer 2222 disposed on one side of the negative electrode current collector 2221 may be, but is not limited to, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, etc.

[0240] According to some embodiments of the present application, a dimension X of the first edge 221 a extending beyond the second edge 222 a satisfies 0.3 mm ≤ X ≤ 8 mm.

[0241] Alternatively, X may be, but is not limited to, 0.3 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, etc.

[0242] In the above solution, the dimension of the first edge 221 a exceeding the second edge 222 a satisfies the above relationship, the difficulty of processing and manufacturing is low, and the impact on the energy and energy density of the battery cell 20 is small.

[0243] According to some embodiments of the present application, 1.5 mm ≤ X ≤ 4 mm.

[0244] Alternatively, X may be, but is not limited to, 1.5 mm, 1.75 mm, 2 mm, 2.25 mm, 2.5 mm, 2.75 mm, 3 mm, 3.25 mm, 3.5 mm, 3.75 mm, 4 mm, etc.

[0245] In the above solution, compared with 0.3 mm ≤ X ≤ 8 mm, when 1.5 mm ≤ X ≤ 4 mm, it is easier to process and manufacture, and the impact on the energy and energy density of the battery cell 20 is further reduced.

[0246] In some embodiments, the dimension of the third edge 221b exceeding the fourth edge 222b in the first direction X, the dimension of the fifth edge 221c exceeding the seventh edge 222c in the second direction Y, and the dimension of the sixth edge 221d exceeding the eighth edge 222d in the second direction Y can all be X.

[0247] According to some embodiments of the present application, an embodiment of the present application provides a battery 100, including a battery cell 20 provided in any of the above embodiments.

[0248] According to some embodiments of the present application, an electrical device is provided, including a battery cell 20 or a battery 100 as provided in any of the above embodiments, where the battery cell 20 or the battery 100 is used to provide electrical energy.

[0249] The electrical equipment may be any of the above-mentioned devices or systems using the battery cell 20 or the battery 100 .

[0250] According to some embodiments of the present application, an electrode assembly 22 is provided, which includes a positive electrode sheet 221, a negative electrode sheet 222, and a separator 220 disposed between the positive electrode sheet 221 and the negative electrode sheet 222. The positive electrode sheet 221 includes a first edge 221a and a third edge 221b disposed opposite each other in a first direction X, and a fifth edge 221c and a sixth edge 221d disposed opposite each other in a second direction Y. The negative electrode sheet 222 includes a second edge 222a corresponding to the first edge 221a, a fourth edge 222b corresponding to the third edge 221b, a seventh edge 222c corresponding to the fifth edge 221c, and an eighth edge 222d corresponding to the sixth edge 221d. The positive electrode sheet 221 includes a positive current collector 2211 and a positive active material layer 2212. The first edge 221a, third edge 221b, fifth edge 221c, and sixth edge 221d are all edges of the positive current collector 2211. The positive electrode tab 2213 extends from the first edge 221a. The negative electrode sheet 222 includes a negative current collector 2221 and a metal layer 2222. The second edge 222a, fourth edge 222b, seventh edge 222c, and eighth edge 222d are all edges of the negative current collector 2221. The negative current collector 2221 is copper foil, and the metal layer 2222 is a lithium metal layer; alternatively, the negative current collector 2221 is aluminum foil, and the metal layer 2222 is a sodium metal layer.

[0251] In the first direction X, the first edge 221a extends beyond the second edge 222a. The positive electrode sheet 221 includes a first hollow foil region 2215 located between the positive active material layer 2212 and the first edge 221a along the first direction X. The electrode assembly 22 also includes a first insulating member 223. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the second edge 222a falls within the orthographic projection of the first insulating member 223. The surface of the first insulating member 223 facing away from the positive current collector 2211 does not exceed the surface of the positive active material layer 2212 facing away from the positive current collector 2211. The first insulating member 223 is an insulating coating applied to the positive current collector 2211, or alternatively, an insulating adhesive layer applied to the positive current collector 2211.

[0252] When the electrode assembly 22 has a wound structure, in some embodiments, in the first direction X, the second edge 222a extends beyond the positive electrode active material layer 2212, the third edge 221b extends beyond the fourth edge 222b, and the fourth edge 222b extends beyond the positive electrode active material layer 2212. The positive electrode sheet 221 includes a second hollow foil region 2216, which is located between the positive electrode active material layer 2212 and the third edge 221b along the first direction X. The electrode assembly 22 also includes a second insulating member 224, which covers the second hollow foil region 2216. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the fourth edge 222b falls within the orthographic projection of the second insulating member 224. Along the thickness direction Z of the positive electrode sheet, the surface of the second insulating member 224 facing away from the positive electrode current collector 2211 does not extend beyond the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211. The second insulating member 224 is an insulating coating applied to the positive electrode current collector 2211 , or the second insulating member 224 is an insulating adhesive layer attached to the positive electrode current collector 2211 .

[0253] When the electrode assembly 22 has a wound structure, in some embodiments, in the first direction X, the third edge 221b extends beyond the fourth edge 222b, and the positive active material layer 2212 extends to the third edge 221b. The electrode assembly 22 also includes a third insulating member 225. Part of the third insulating member 225 is disposed in the portion of the positive active material layer 2212 that extends beyond the fourth edge 222b. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the fourth edge 222b falls within the orthographic projection of the third insulating member 225. The thickness of the third insulating member 225 is less than the thickness of the positive active material layer 2212. The third insulating member 225 can be an insulating coating or an insulating adhesive layer.

[0254] When the electrode assembly 22 is a laminated structure, in some embodiments, along the second direction Y, the fifth edge 221c exceeds the seventh edge 222c, the sixth edge 221d exceeds the eighth edge 222d, and both ends of the positive electrode active material layer 2212 extend to the fifth edge 221c and the sixth edge 221d, and the second direction Y is perpendicular to the first direction X. The electrode assembly 22 also includes a fourth insulating member 226 and a fifth insulating member 227. A portion of the fourth insulating member 226 is disposed on the portion of the positive active material layer 2212 that extends beyond the seventh edge 222c. The thickness of the fourth insulating member 226 is less than that of the positive active material layer 2212. A portion of the fifth insulating member 227 is disposed on the portion of the positive active material layer 2212 that extends beyond the eighth edge 222d. The thickness of the fifth insulating member 227 is less than that of the positive active material layer 2212. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the seventh edge 222c falls within the orthographic projection of the fourth insulating member 226, and the orthographic projection of the eighth edge 222d falls within the orthographic projection of the fifth insulating member 227. The fourth insulating member 226 is an insulating coating or an insulating adhesive layer; the fifth insulating member 227 is an insulating coating or an insulating adhesive layer.

[0255] When the electrode assembly 22 has a laminated structure, in some embodiments, along the second direction Y, the fifth edge 221c extends beyond the seventh edge 222c, the seventh edge 222c extends beyond the positive electrode active material layer 2212, the sixth edge 221d extends beyond the eighth edge 222d, and the eighth edge 222d extends beyond the positive electrode active material layer 2212. The positive electrode sheet 221 has a third hollow foil region 2217 and a fourth hollow foil region 2218. Along the second direction Y, the third hollow foil region 2217 is located between the fifth edge 221c and the positive electrode active material layer 2212, and the fourth hollow foil region 2218 is located between the sixth edge 221d and the positive electrode active material layer 2212. The electrode assembly 22 further includes a sixth insulating member 228 and a seventh insulating member 229. The sixth insulating member 228 covers the third hollow foil region 2217, and the seventh insulating member 229 covers the fourth hollow foil region 2218. Along the thickness direction Z of the positive electrode sheet, the orthographic projection of the seventh edge 222c falls within the orthographic projection of the sixth insulating member 228, and the orthographic projection of the eighth edge 222d falls within the orthographic projection of the seventh insulating member 229. Along the thickness direction Z of the positive electrode sheet, the surface of the sixth insulating member 228 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211, and the surface of the seventh insulating member 229 facing away from the positive electrode current collector 2211 does not exceed the surface of the positive electrode active material layer 2212 facing away from the positive electrode current collector 2211. The sixth insulating member 228 and the seventh insulating member 229 are both insulating coatings coated on the positive electrode current collector 2211 , or the sixth insulating member 228 and the seventh insulating member 229 are both insulating adhesive layers attached to the positive electrode current collector 2211 .

[0256] According to the electrode assembly 22 of the embodiment of the present application, during the charge and discharge cycle of the battery cell 20, the extrusion and shearing effect of the expansion of the positive electrode plate 221 on the negative electrode plate 222 can be reduced, and the risk of the negative electrode plate 222 being sheared and broken can be reduced, so that the battery cell 20 composed of the electrode assembly 22 has higher reliability.

[0257] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A battery cell, comprising an electrode assembly, wherein the electrode assembly comprises a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet comprises a first edge in a first direction, and the negative electrode sheet comprises a second edge corresponding to the first edge, and along the first direction, the first edge exceeds the second edge.

2. The battery cell according to claim 1, wherein: The thickness of the negative electrode plate is H1, and the thickness of the positive electrode plate is H2, satisfying that H1<H2.

3. The battery cell according to claim 1 or 2, wherein: The thickness of the negative electrode plate is H1, which satisfies 5 μm≤H1≤100 μm.

4. The battery cell according to claim 3, wherein: 10μm≤H1≤80μm.

5. The battery cell according to any one of claims 1 to 4, wherein: The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer, wherein the positive electrode active material layer is arranged on the surface of the positive electrode collector, the positive electrode collector has the first edge, and the positive electrode sheet also includes a positive electrode tab, and the positive electrode tab extends from the first edge.

6. The battery cell according to claim 5, wherein: Along the first direction, the second edge exceeds the positive electrode active material layer, the positive electrode current collector has a first empty foil area, the first empty foil area is located between the first edge and the positive electrode active material layer, the electrode assembly also includes a first insulating member, the first insulating member covers the first empty foil area, and along the thickness direction of the positive electrode sheet, the orthographic projection of the second edge falls within the orthographic projection of the first insulating member.

7. The battery cell according to claim 6, wherein: Along the thickness direction of the positive electrode sheet, a surface of the first insulating member facing away from the positive current collector does not exceed a surface of the positive active material layer facing away from the positive current collector.

8. The battery cell according to claim 6 or 7, wherein: The first insulating member is an insulating coating or an insulating rubber layer.

9. The battery cell according to any one of claims 1 to 8, wherein: The positive electrode plate also has a third edge, which is arranged opposite to the first edge along the first direction. The negative electrode plate also has a fourth edge corresponding to the third edge, which is arranged opposite to the second edge along the first direction. Along the first direction, the third edge exceeds the fourth edge.

10. The battery cell according to claim 9, wherein: The positive electrode plate includes a positive electrode collector and a positive electrode active material layer, the positive electrode active material layer is arranged on the surface of the positive electrode collector, along the first direction, the fourth edge exceeds the positive electrode active material layer, the positive electrode collector has a second empty foil area, the second empty foil area is located between the third edge and the positive electrode active material layer, the electrode assembly also includes a second insulating member, the second insulating member covers the second empty foil area, along the thickness direction of the positive electrode plate, the orthographic projection of the fourth edge falls within the orthographic projection of the second insulating member.

11. The battery cell according to claim 10, wherein: Along the thickness direction of the positive electrode sheet, a surface of the second insulating member facing away from the positive electrode collector does not exceed a surface of the positive electrode active material layer facing away from the positive electrode collector.

12. The battery cell according to claim 10 or 11, wherein: The second insulating member is an insulating coating layer coated on the positive electrode current collector, or the second insulating member is an insulating glue layer attached to the positive electrode current collector.

13. The battery cell according to any one of claims 9 to 12, wherein: The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is arranged on the surface of the positive electrode current collector. Along the first direction, the positive electrode active material layer extends to the third edge.

14. The battery cell according to claim 13, wherein: The electrode assembly further includes a third insulating member, and a portion of the third insulating member is disposed at a portion of the positive electrode active material layer that exceeds the fourth edge.

15. The battery cell according to claim 14, wherein: Along the thickness direction of the positive electrode sheet, the orthographic projection of the fourth edge falls within the orthographic projection of the third insulating member, and the thickness of the third insulating member is less than the thickness of the positive electrode active material layer.

16. The battery cell according to claim 14 or 15, wherein: The third insulating member is an insulating coating or an insulating rubber layer.

17. The battery cell according to any one of claims 1 to 16, wherein: The positive electrode plate also has a third edge, a fifth edge and a sixth edge, the third edge is arranged opposite to the first edge along the first direction, the fifth edge connects the first end of the first edge and the first end of the third edge, the sixth edge connects the second end of the first edge and the second end of the third edge, the negative electrode plate also has a seventh edge corresponding to the fifth edge, and an eighth edge corresponding to the sixth edge, along the second direction, the fifth edge exceeds the seventh edge, and / or the sixth edge exceeds the eighth edge, and the second direction is perpendicular to the first direction.

18. The battery cell according to claim 17, wherein: The positive electrode sheet includes a positive current collector and a positive active material layer, wherein the positive active material layer is disposed on the surface of the positive current collector, and along the second direction, the positive active material layer extends to the fifth edge, and / or the positive active material layer extends to the sixth edge.

19. The battery cell according to claim 18, wherein: The electrode assembly also includes a fourth insulating member, part of which is disposed on a portion of the positive electrode active material layer that exceeds the seventh edge, and the thickness of the fourth insulating member is less than the thickness of the positive electrode active material layer, and along the thickness direction of the positive electrode sheet, the orthographic projection of the seventh edge falls within the orthographic projection of the fourth insulating member; and / or, the electrode assembly also includes a fifth insulating member, part of which is disposed on a portion of the positive electrode active material layer that exceeds the eighth edge, and the thickness of the fifth insulating member is less than the thickness of the positive electrode active material layer, and along the thickness direction of the positive electrode sheet, the orthographic projection of the eighth edge falls within the orthographic projection of the fifth insulating member.

20. The battery cell according to claim 19, wherein: The fourth insulating member is an insulating coating or an insulating adhesive layer; and / or the fifth insulating member is an insulating coating or an insulating adhesive layer.

21. The battery cell according to any one of claims 1 to 20, wherein: The negative electrode plate includes a negative electrode current collector and a metal layer, and the metal layer is arranged on the surface of the negative electrode current collector.

22. The battery cell according to claim 21, wherein: The negative electrode current collector is copper foil, and the metal layer is a lithium metal layer; or, the negative electrode current collector is aluminum foil or copper foil, and the metal layer is a sodium metal layer.

23. The battery cell according to any one of claims 1 to 22, wherein: The negative electrode plate includes a negative electrode current collector, and no active material layer is arranged on the surface of the negative electrode current collector.

24. The battery cell according to any one of claims 1 to 23, wherein: The dimension of the first edge exceeding the second edge is X, which satisfies 0.3 mm ≤ X ≤ 8 mm.

25. The battery cell according to claim 24, wherein: 1.5mm≤X≤4mm.

26. A battery comprising the battery cell according to any one of claims 1 to 25.

27. An electrical device, comprising the battery cell according to any one of claims 1 to 25 or the battery according to claim 26, wherein the battery cell or the battery is used to provide electrical energy.

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