Battery cell, battery, and electrical device

Abstract

A battery cell, a battery, and an electrical device. The battery cell comprises a housing and a first conductive layer. The housing comprises a first wall part. The first wall part has a first surface, and is provided with a recess. The recess has a side surface connected to the first surface. The first conductive layer is accommodated in the recess, and is in contact with the side surface. The arrangement of the first conductive layer improves the electric field distribution in the area of the first wall part where the recess is provided, enables a uniform electric field intensity distribution, reduces the risk of point discharge at the connection location between the side surface and the first surface in high-voltage environments, and improves the reliability of the battery cell.

Description

Battery cells, batteries and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application (2023108787688) entitled “Battery Cell, Battery and Electrical Equipment” filed on July 18, 2023, 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] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and power tools.

[0005] In the development of battery technology, in addition to improving the performance of battery cells, the reliability of battery cells is also an issue that needs to be considered. Therefore, how to improve the reliability of battery cells is an urgent problem to be solved in battery technology.

[0006] Summary of the Invention

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

[0008] In a first aspect, embodiments of the present application provide a battery cell comprising a housing and a first conductive layer. The housing comprises a first wall portion having a first surface and a recessed portion having a side surface connected to the first surface; the first conductive layer is accommodated in the recessed portion and contacts the side surface.

[0009] In the above technical solution, a first conductive layer in contact with the side surface is provided in the recess. The provision of the first conductive layer improves the electric field distribution of the first wall in the area where the recess is provided, and the electric field strength distribution is more uniform, thereby reducing the risk of tip discharge at the position where the side surface is connected to the first surface in a high-voltage environment, thereby improving the reliability of the battery cell.

[0010] In some embodiments, the first conductive layer extends from the first surface into the recess. This prevents the entire first conductive layer from being lower than the first surface, thereby eliminating discharge spikes at the junction of the side surface and the first surface, and further reducing the risk of discharge spikes at the junction of the side surface and the first surface in a high-voltage environment.

[0011] In some embodiments, the recess has a bottom surface facing the first conductive layer, the bottom surface being connected to the side surface; and the first conductive layer is in contact with the bottom surface. This can reduce the risk of sharp discharge at the connection point between the bottom surface and the side surface of the recess in a high-voltage environment, further improving the reliability of the battery cell.

[0012] In some embodiments, the first conductive layer fills the concave portion, which is helpful in eliminating as many discharge tips of the first wall portion in the region where the concave portion is provided as possible.

[0013] In some embodiments, the recess has a bottom surface facing the first conductive layer, the bottom surface is connected to the side surface, and a gap is provided between the first conductive layer and the first surface, thereby reducing the material used for the first conductive layer and saving costs.

[0014] In some embodiments, the maximum thickness of the first conductive layer is H1, and the maximum depth of the recess is H2, satisfying the following: 0.1 ≤ H1 / H2 ≤ 1. This prevents the thickness of the first conductive layer from being too thin, and prevents the first conductive layer from failing due to such a thin thickness, thereby facilitating the elimination of discharge spikes at the junction of the side surface and the first surface.

[0015] In some embodiments, 0.4≤H1 / H2≤1. Further increasing the thickness of the first conductive layer is beneficial to eliminating the discharge tip at the position where the side surface connects to the first surface, and is beneficial to increasing the contact area between the first conductive layer and the first wall.

[0016] In some embodiments, the first conductive layer has a second surface furthest from the bottom surface of the recess, and the second surface of the first conductive layer is flush with the first surface. This makes the second surface coplanar with the first surface, and the first wall portion in the region where the recess is located is flatter, resulting in a more uniform electric field intensity distribution in that region.

[0017] In some embodiments, the first conductive layer is a conductive adhesive layer bonded to the first wall. This provides a high connection strength between the first conductive layer and the first wall, and prevents the first conductive layer from falling out of the recess. During molding, the conductive adhesive is applied to the recess to form the first conductive layer, making molding of the first conductive layer easier.

[0018] In some embodiments, the battery cell further includes a second conductive layer having a third surface that contacts the first surface. The first conductive layer extends from the third surface toward the interior of the recess, with the second conductive layer covering the recess. This conceals the recess, enhancing the aesthetics. Furthermore, the third surface of the second conductive layer contacts the first surface, while the first conductive layer contacts the side surface, thereby eliminating discharge spikes at the junction of the side surface and the first surface.

[0019] In some embodiments, the second conductive layer covers the first surface, thereby reducing the risk of a discharge tip being formed between the outer peripheral surface of the second conductive layer and the first surface.

[0020] In some embodiments, the surface of the second conductive layer facing away from the first surface is flat, thereby reducing the risk of discharge spikes being formed due to unevenness of the surface of the second conductive layer facing away from the first surface.

[0021] In some embodiments, the maximum thickness of the first conductive layer is H1, the maximum depth of the recess is H2, and the maximum thickness of the second conductive layer is H3, satisfying the following: 0.1 ≤ (H1 + H3) / H2 ≤ 20. (H1 + H3) / H2 ≥ 0.1, ensuring that the total thickness of the first and second conductive layers is not too small, ensuring sufficient structural strength. (H1 + H3) / H2 ≤ 20, ensuring that the total thickness of the first and second conductive layers is not too large, reducing material usage and lowering production costs.

[0022] In some embodiments, 1≤(H1+H3) / H2≤5.

[0023] In some embodiments, the first conductive layer and the second conductive layer are integrally formed, which has good structural strength and reduces the difficulty of forming the first conductive layer and the second conductive layer.

[0024] In some embodiments, the second conductive layer is a conductive adhesive layer bonded to the first wall. This provides a strong connection between the second conductive layer and the first wall, making it difficult for the second conductive layer to separate from the first surface. During molding, applying the conductive adhesive to the first surface forms the corresponding second conductive layer, making molding of the second conductive layer easier.

[0025] In some embodiments, the conductivity of the first wall is Q1, the conductivity of the first conductive layer is Q2, and 0.5≤Q2 / Q1≤1.5. This ensures that the conductivity of the first conductive layer and the first wall are approximately equal, resulting in relatively similar conductivity properties between the first conductive layer and the first wall, which helps eliminate discharge spikes at the junction of the side surface and the first surface.

[0026] In some embodiments, along the thickness direction of the first wall portion, the first surface faces the interior of the housing; alternatively, the first surface faces the exterior of the housing. If the first surface faces the interior of the housing, the recess is located on the interior side of the first wall portion, preventing the first conductive layer from being exposed to the exterior of the housing. The housing protects the first conductive layer, making it less susceptible to damage. If the first surface faces the exterior of the housing, the groove is located on the exterior side of the first wall portion, facilitating placement of the first conductive layer within the recess.

[0027] In some embodiments, the concave portion is a groove provided on the first surface, and the groove side surface of the groove is the side surface. The provision of the first conductive layer is conducive to eliminating the discharge tip at the position where the groove side surface of the groove connects with the first surface.

[0028] In some embodiments, the first wall portion forms a weak portion in the region where the groove is provided, and the weak portion is configured to rupture to release pressure within the battery cell. This provides the first wall portion with a pressure relief function; in the event of thermal runaway of the battery cell, the weak portion can rupture to release pressure within the battery cell.

[0029] In some embodiments, the groove side surface includes a first side surface and a second side surface disposed opposite each other, and both the first side surface and the second side surface are in contact with the first conductive layer. This helps eliminate discharge spikes at the location where the first side surface connects to the first surface and discharge spikes at the location where the second side surface connects to the first surface.

[0030] In some embodiments, the groove includes a first groove section and a second groove section, the second groove section being connected to the first groove section and extending in a direction that intersects with the first groove section's direction of extension. The first conductive layer includes a first conductive portion and a second conductive portion, the first conductive portion being located within the first groove section and contacting the groove side of the first groove section, while the second conductive portion being located within the second groove section and contacting the groove side of the second groove section. Because the second groove section is connected to the first groove section and their extending directions intersect, the first wall section can partially flip open after the weak portion ruptures along the first and second groove sections. This effectively increases the pressure relief area of ​​the first wall section and improves the timeliness of pressure relief during thermal runaway of the battery cell. The first conductive portion of the first conductive layer is located within the first groove section and in contact with the groove side of the first groove section, thereby facilitating the elimination of discharge spikes at the location where the groove side of the first groove section connects to the first surface. The second conductive portion of the first conductive layer is located within the second groove section and in contact with the groove side of the second groove section, thereby facilitating the elimination of discharge spikes at the location where the groove side of the second groove section connects to the first surface.

[0031] In some embodiments, along the width direction of the first slot segment, the slot side surfaces of the first slot segment include first and second side surfaces disposed opposite each other, both of which are in contact with the first conductive portion; and / or, along the width direction of the second slot segment, the slot side surfaces of the second slot segment include third and fourth side surfaces disposed opposite each other, both of which are in contact with the second conductive portion. The first and second side surfaces are both in contact with the first conductive portion, facilitating the elimination of discharge spikes at the locations where the first side surface connects to the first surface and where the second side surface connects to the first surface. The third and fourth side surfaces are both in contact with the second conductive portion, facilitating the elimination of discharge spikes at the locations where the third side surface connects to the first surface and where the fourth side surface connects to the first surface.

[0032] In some embodiments, the groove further includes a third groove segment, the first groove segment and the third groove segment are arranged opposite each other, and the second groove segment connects the first and third groove segments. The first conductive layer further includes a third conductive portion, which is located within the third groove segment and contacts the groove side surface of the third groove segment. The area defined by the first, second, and third groove segments is larger, thereby increasing the area of ​​the portion of the first wall that flips open after the weak portion ruptures along the first, second, and third groove segments, further increasing the pressure relief area of ​​the first wall. The third conductive portion of the first conductive layer is located within the third groove segment and contacts the groove side surface of the third groove segment, which helps eliminate discharge tips at the location where the groove side surface of the third groove segment connects with the first surface.

[0033] In some embodiments, along the width direction of the third slot segment, the slot side surfaces of the third slot segment include a fifth side surface and a sixth side surface disposed opposite each other, and both the fifth side surface and the sixth side surface are in contact with the third conductive portion. Both the fifth side surface and the sixth side surface are in contact with the third conductive portion, which facilitates eliminating discharge spikes at locations where the fifth side surface connects to the first surface and where the sixth side surface connects to the first surface.

[0034] In some embodiments, the groove is a slot extending along a closed trajectory. After the weak portion ruptures along the extending direction of the groove, the area of ​​the first wall portion defined by the groove can be completely detached and opened. The opening of this area is less susceptible to the influence of the first conductive layer, and the pressure relief is more timely, with a larger pressure relief area.

[0035] In some embodiments, the first wall portion includes a wall body and a convex portion; the wall body has a fourth surface; the convex portion is disposed on the fourth surface; the outer peripheral surface of the convex portion and the fourth surface together define a concave portion, which surrounds the convex portion; the outer peripheral surface of the convex portion is a side surface; and the end surface of the convex portion away from the fourth surface is the first surface. The provision of the first conductive layer facilitates eliminating discharge spikes at the location where the outer peripheral surface of the convex portion connects with the first surface.

[0036] In some embodiments, along a circumference of the recess, the first conductive layer is in contact with the side surface throughout the entire circumference.

[0037] In some embodiments, the housing comprises a shell and an end cap; the shell has an opening; the end cap closes the opening; wherein the end cap is the first wall portion; and / or at least one wall portion in the shell is the first wall portion.

[0038] In some embodiments, the first wall is provided with an insulating member, with the first surface facing the insulating member. The provision of the insulating member can insulate the first wall from other components. The provision of the first conductive layer within the recess of the first wall improves the electric field distribution within the recess, making the electric field intensity distribution more uniform and reducing the risk of insulation failure caused by breakdown of the insulating member due to tip discharge.

[0039] In some embodiments, the battery cell also includes an electrode assembly, which is housed in a shell with the first surface facing the interior of the shell, and the insulating member is arranged on the side of the first wall facing the electrode assembly; or, the first surface faces the outside of the shell, and the insulating member is arranged on the side of the first wall facing away from the electrode assembly.

[0040] In a second aspect, an embodiment of the present application provides a battery, comprising a battery cell provided by any embodiment of the first aspect.

[0041] In a third aspect, an embodiment of the present application provides an electrical device, comprising a battery cell provided by any embodiment of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] 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.

[0043] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0044] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0045] FIG3 is an exploded view of a battery cell provided in some embodiments of the present application;

[0046] FIG4 is a schematic structural diagram of a battery cell provided in some embodiments of the present application (the first conductive layer is separated from the outer shell);

[0047] FIG5 is a partial view of the battery cell shown in FIG4 ;

[0048] FIG6 is a cross-sectional view AA in FIG5;

[0049] FIG7 is a schematic diagram of the connection between the first conductive layer and the first wall portion provided in some other embodiments of the present application;

[0050] FIG8 is a schematic diagram showing connections between a first conductive layer, a second conductive layer, and a first wall portion according to some embodiments of the present application;

[0051] FIG9 is a schematic diagram of connections between a first conductive layer, a second conductive layer, and a first wall portion provided by other embodiments of the present application;

[0052] FIG10 is a schematic structural diagram of the first wall portion shown in FIG6 ;

[0053] FIG11 is a schematic structural diagram of a battery cell provided in some other embodiments of the present application (the first conductive layer is separated from the outer shell);

[0054] FIG12 is a partial view of the battery cell shown in FIG11 ;

[0055] FIG13 is a sectional view BB in FIG12;

[0056] FIG14 is a CC sectional view in FIG12;

[0057] FIG15 is a schematic structural diagram of a battery cell provided in some further embodiments of the present application (the first conductive layer is separated from the outer shell);

[0058] FIG16 is a partial view of the battery cell shown in FIG15 ;

[0059] FIG17 is a DD sectional view in FIG16;

[0060] FIG18 is a schematic structural diagram of a battery cell provided in yet other embodiments of the present application (the first conductive layer is separated from the outer shell);

[0061] FIG19 is a schematic structural diagram of a battery cell provided in another embodiment of the present application (the first conductive layer is separated from the outer shell);

[0062] FIG20 is a partial view of the battery cell shown in FIG19;

[0063] FIG21 is a cross-sectional view EE in FIG20;

[0064] FIG22 is a schematic diagram showing connections between a first conductive layer, a second conductive layer, and a first wall portion provided in some further embodiments of the present application;

[0065] FIG23 is an exploded view of a housing provided in some embodiments of the present application;

[0066] FIG24 is an exploded view of a housing provided in some other embodiments of the present application;

[0067] FIG25 is an exploded view of a housing provided in some further embodiments of the present application.

[0068] Icons: 1-shell; 11-shell; 12-end cover; 13-first wall; 131-first surface; 132-recess; 1321-side surface; 1322-bottom surface; 133-groove; 1331-first groove section; 1332-second groove section; 1333-third groove section; 1334-first side surface; 1335-second side surface; 1336-third side surface; 1337-fourth side surface; 1338-fifth side surface; 1339-sixth side surface; 134-weak part; 135-wall body; 13 51-fourth surface; 136-protrusion; 14-insulating member; 2-electrode assembly; 21-tab; 3-electrode terminal; 4-current collecting member; 5-first conductive layer; 51-second surface; 52-first conductive part; 53-second conductive part; 54-third conductive part; 6-second conductive layer; 61-third surface; 10-battery cell; 20-casing; 201-first part; 202-second part; 100-battery; 200-controller; 300-motor; 1000-vehicle; Z-thickness direction. DETAILED DESCRIPTION

[0069] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0070] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0075] The term "plurality" used in this application refers to two or more (including two).

[0076] 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.

[0077] Battery cells include 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, etc.

[0078] 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, active ions (such as lithium ions) move back and forth between the positive and negative electrodes. A separator, placed between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0079] 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.

[0080] 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.

[0081] 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.).

[0082] 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 traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05O2) and at least one of its modified compounds, etc.

[0083] In some embodiments, a positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, among others. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0084] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0085] As an example, the negative electrode current collector can be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium can be used. The metal foam can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0086] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0087] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0088] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells 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.

[0089] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0090] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical and mechanical stability.

[0091] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. 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.

[0092] 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.

[0093] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0094] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0095] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0096] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0097] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0098] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0099] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0100] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[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] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0104] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0105] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0106] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0107] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0108] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0109] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0110] 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.

[0111] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include square-shell, blade-shaped, and polygonal batteries. Polygonal batteries may be, for example, hexagonal batteries.

[0112] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0117] A typical battery cell consists of a housing and an electrode assembly, with the electrode assembly housed within the housing. To insulate the housing from other components, insulating members can be installed on the surface of the housing's walls. For example, insulating members can be installed on the inner surface of the wall to insulate the wall from the electrode assembly; or on the outer surface of the wall to insulate the wall from external components.

[0118] To meet the operational requirements of the battery cells, the surface of the housing's wall may have an uneven structure. For example, to meet the pressure relief requirements of the battery cells, grooves may need to be provided on the wall surface so that the wall cracks along the grooves during thermal runaway to achieve pressure relief. Due to the uneven surface structure of the wall, the electric field strength distribution in the uneven areas of the wall may be uneven when the battery cells are in high-voltage environments, such as energy storage systems. These uneven areas are prone to tip discharge, which can lead to the risk of insulation failure and affect the reliability of the battery cells.

[0119] In view of this, an embodiment of the present application provides a battery cell, wherein the first wall portion of the shell is provided with a recess, the recess has a side surface connected to the first surface of the first wall portion, a first conductive layer is provided in the recess, the first conductive layer extends from the first surface into the recess, and is connected to the side surface.

[0120] In such a battery cell, the provision of the first conductive layer improves the electric field distribution of the first wall portion in the area where the recess is provided, making the electric field strength distribution more uniform, reducing the risk of tip discharge at the position where the side surface is connected to the first surface in a high-voltage environment, and improving the reliability of the battery cell.

[0121] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0122] Electrically powered equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be fuel-powered, gas-powered, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles. Spacecraft include aircraft, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0123] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0124] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present application. A battery 100 is disposed within vehicle 1000. Battery 100 can be located at the bottom, front, or rear of vehicle 1000. Battery 100 can be used to power vehicle 1000, for example, as an operating power source for vehicle 1000.

[0125] 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.

[0126] 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.

[0127] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 may include a battery cell 10 and a housing 20, wherein the battery cell 10 is accommodated in the housing 20.

[0128] The housing 20 is a component that houses the battery cells 10 and provides a storage space for the battery cells 10. The housing 20 can have various structures. In some embodiments, the housing 20 can include a first portion 201 and a second portion 202, which overlap to define a storage space for the battery cells 10. The first portion 201 and the second portion 202 can have various shapes, such as a rectangular parallelepiped or a cylinder. The first portion 201 can be a hollow structure with one side open, and the second portion 202 can also be a hollow structure with one side open. The open side of the second portion 202 overlaps the open side of the first portion 201, forming the housing 20 with a storage space. Alternatively, the first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a plate-like structure. The second portion 202 overlaps the open side of the first portion 201, forming the housing 20 with a storage space. The first portion 201 and the second portion 202 can be sealed by a sealing element, which can be a sealing ring, sealant, etc.

[0129] In the battery 100, there can be one or more battery cells 10. If there are multiple battery cells 10, the multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 10. Multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection to form a battery module, which can then be connected in series, parallel, or in a hybrid connection to form a single unit and housed within the housing 20. Alternatively, all battery cells 10 can be directly connected in series, parallel, or in a hybrid connection, and then the entire unit formed by all battery cells 10 can be housed within the housing 20.

[0130] Please refer to Figure 3, which is an exploded view of a battery cell 10 provided in some embodiments of the present application. The battery cell 10 may include a housing 1 and an electrode assembly 2, wherein the electrode assembly 2 is accommodated in the housing 1.

[0131] In some embodiments, the housing 1 may include a shell 11 and an end cover 12 , wherein the shell 11 has an opening and the end cover 12 closes the opening of the shell 11 .

[0132] The housing 11 is a component for accommodating the electrode assembly 2. The housing 11 can be a hollow structure with an opening at one end, or a hollow structure with openings at opposite ends. The housing 11 can have various shapes, such as a cylinder or a rectangular parallelepiped. The housing 11 can be made of various materials, such as copper, iron, aluminum, steel, and aluminum alloys.

[0133] The end cap 12 is a component that closes the opening of the shell 11 to isolate the internal environment of the battery cell 10 from the external environment. The end cap 12 and the shell 11 together define a storage space for accommodating the electrode assembly 2, electrolyte and other components. The end cap 12 can be connected to the shell 11 by welding or rolling to close the opening of the shell 11. The shape of the end cap 12 can be adapted to the shape of the shell 1. For example, the shell 11 is a rectangular parallelepiped structure, and the end cap 12 is a rectangular plate structure adapted to the shell 1. For another example, the shell 11 is a cylindrical structure, and the end cap 12 is a circular plate structure adapted to the shell 11. The material of the end cap 12 can also be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 12 and the shell 11 can be the same or different.

[0134] In an embodiment where the housing 11 is open at one end, one end cap 12 may be provided. In an embodiment where the housing 11 is open at two opposite ends, two end caps 12 may be provided, each of which closes the two openings of the housing 11, and the two end caps 12 and the housing 11 together define a receiving space.

[0135] In some embodiments, the battery cell 10 may further include an electrode terminal 3, which is disposed on the outer casing 1. The electrode terminal 3 is used to electrically connect to the tab 21 of the electrode assembly 2 to output electrical energy from the battery cell 10. The electrode terminal 3 may be disposed on the shell 11 of the outer casing 1 or on the end cap 12 of the outer casing 1. The electrode terminal 3 and the tab 21 may be directly connected, for example, by direct welding the electrode terminal 3 and the tab 21. The electrode terminal 3 and the tab 21 may also be indirectly connected, for example, by indirectly connecting the electrode terminal 3 and the tab 21 through a current collecting member 4. The current collecting member 4 may be a metal conductor, such as copper, iron, aluminum, steel, an aluminum alloy, or the like.

[0136] As an example, as shown in FIG3 , an opening is formed at one end of the housing 11. There is only one end cap 12 in the outer shell 1, and each end cap 12 closes the opening of the housing 11. Two electrode terminals 3 are provided on the end cap 12, which are respectively a positive electrode terminal and a negative electrode terminal. A positive electrode tab and a negative electrode tab are formed on the end of the electrode assembly 2 facing the end cap 12. The positive electrode terminal is connected to the positive electrode tab via a current collecting member 4, and the negative electrode terminal is connected to the negative electrode tab via another current collecting member 4.

[0137] Please refer to Figures 4 to 6. Figure 4 is a schematic structural diagram of a battery cell 10 provided in some embodiments of the present application (the first conductive layer 5 is separated from the outer shell 1); Figure 5 is a partial view of the battery cell 10 shown in Figure 4; and Figure 6 is an AA cross-sectional view in Figure 5. An embodiment of the present application provides a battery cell 10, comprising an outer shell 1 and a first conductive layer 5. The outer shell 1 includes a first wall portion 13, the first wall portion 13 having a first surface 131, the first wall portion 13 being provided with a recess 132, the recess 132 having a side surface 1321 connected to the first surface 131. The first conductive layer 5 is accommodated in the recess 132, and the first conductive layer 5 is in contact with the side surface 1321.

[0138] The first wall portion 13 may be the end cover 12 of the outer shell 1, or may be at least one wall portion in the shell 11 of the outer shell 1, or may be a pressure relief component mounted on the end cover 12 or the shell 11, and the pressure relief component may be a burst-proof disk, a pressure relief valve, or other components.

[0139] The first surface 131 may be the outer surface of the first wall portion 13 or the inner surface of the first wall portion 13 , wherein the inner surface of the first wall portion 13 faces the inside of the housing 1 , and the outer surface of the first wall portion 13 faces the outside of the housing 1 .

[0140] The depth direction of the recess 132 can be parallel to the thickness direction Z of the first wall portion 13. The recess 132 can be a groove provided on the first surface 131, or a convex portion can be formed on the first wall portion 13, and the recess 132 is a surrounding recessed structure formed on the convex portion. The side surface 1321 is a surface of the recess 132 extending in the circumferential direction. The side surface 1321 is connected to the first surface 131. The intersection line of the side surface 1321 and its vertical section can be perpendicular to the first surface 131, or can be set at an obtuse angle or an acute angle to the first surface 131. The vertical section of the side surface 1321 is parallel to the thickness direction Z of the first wall portion 13. Along the circumference of the recess 132, the first conductive layer 5 can be in contact with the side surface 1321 throughout the entire circumference, or can be in partial contact.

[0141] The first conductive layer 5 is made of a conductive material, such as copper, iron, aluminum, steel, aluminum alloy, etc. The first wall portion 13 is also made of a conductive material, and the material of the first wall portion 13 and the material of the first conductive layer 5 can be the same or different. The first conductive layer 5 is in contact with the side surface 1321, thereby achieving electrical connection between the first conductive layer 5 and the first wall portion 13. It should be noted that the first conductive layer 5 can form an interference fit with the side surface 1321, so that the first conductive layer 5 maintains contact with the side surface 1321; or the first conductive layer 5 can be fixedly connected to the side surface 1321, so that the first conductive layer 5 maintains contact with the side surface 1321. The first conductive layer 5 can fill the recess 132 or not fill the recess 132. The first conductive layer 5 can be lower than the first surface 131 as a whole, or it can extend from the first surface 131 into the recess 132.

[0142] In an embodiment of the present application, a first conductive layer 5 connected to the side surface 1321 is provided in the recess 132. The provision of the first conductive layer 5 improves the electric field distribution of the first wall portion 13 in the area where the recess 132 is provided, and the electric field strength distribution is more uniform, thereby reducing the risk of tip discharge at the position where the side surface 1321 is connected to the first surface 131 in a high-voltage environment, thereby improving the reliability of the battery cell 10.

[0143] In some embodiments, the first conductive layer 5 extends from the first surface 131 into the recess 132 .

[0144] In this embodiment, the first conductive layer 5 extends from the first surface 131 into the recess 132, so that the first conductive layer 5 is not lower than the first surface 131 as a whole, which is beneficial to eliminating the discharge tip at the position where the side surface 1321 connects to the first surface 131, and further reducing the risk of tip discharge at the position where the side surface 1321 connects to the first surface 131 in a high-voltage environment.

[0145] In other embodiments, the first conductive layer 5 may be entirely lower than the first surface 131 .

[0146] In some embodiments, the recess 132 has a bottom surface 1322 facing the first conductive layer 5 , and the bottom surface 1322 is connected to the side surface 1321 . The first conductive layer 5 is in contact with the bottom surface 1322 .

[0147] The side surface 1321 and bottom surface 1322 of the recess 132 may collectively define an interior space of the recess 132. The side surface 1321 is connected between the first surface 131 and the bottom surface 1322. The bottom surface 1322 of the recess 132 may be a planar surface; the bottom surface 1322 of the recess 132 may also be a non-planar surface, for example, a circular arc surface, a conical surface, etc.

[0148] In this embodiment, the first conductive layer 5 contacts the bottom surface 1322 , which can reduce the risk of sharp discharge at the connection position between the bottom surface 1322 and the side surface 1321 of the recess 132 in a high-voltage environment, further improving the reliability of the battery cell 10 .

[0149] In some embodiments, the first conductive layer 5 fills the recess 132 .

[0150] It can be understood that the first conductive layer 5 occupies the entire space of the recess 132 .

[0151] In this embodiment, the first conductive layer 5 completely fills the recess 132, which helps to minimize discharge spikes on the first wall portion 13 in the area where the recess 132 is located. For example, if the side surface 1321 is rectangular, the side surface 1321 includes four side surfaces connected end to end along the circumference of the recess 132. Filling the recess 132 with the first conductive layer 5 can eliminate discharge spikes at the junction of two adjacent side surfaces, at the junction of each side surface with the first surface 131, and at the junction of each side surface with the bottom surface 1322.

[0152] In some embodiments, please refer to Figure 7, which is a schematic diagram of the connection between the first conductive layer 5 and the first wall portion 13 provided in other embodiments of the present application. The recess 132 has a bottom surface 1322 facing the first conductive layer 5. The bottom surface 1322 is connected to the side surface 1321, and a gap is provided between the first conductive layer 5 and the first surface 131.

[0153] It can be understood that there is a gap between the first conductive layer 5 and the first surface 131 , and the first conductive layer 5 is not in contact with the first surface 131 .

[0154] In this embodiment, a gap is provided between the first conductive layer 5 and the first surface 131 , which can reduce the material used for the first conductive layer 5 and save costs.

[0155] In some embodiments, the maximum thickness of the first conductive layer 5 is H1, and the maximum depth of the recess 132 is H2, satisfying: 0.1≤H1 / H2≤1.

[0156] The thickness of the first conductive layer 5 at its thickest location is the maximum thickness of the first conductive layer 5. Along the depth direction of the recess 132, the maximum distance between the bottom surface 1322 of the recess 132 and the first surface 131 is the maximum depth of the recess 132. For example, if the bottom surface 1322 of the recess 132 is a plane and parallel to the first surface 131, the distance between the bottom surface 1322 of the recess 132 and the first surface 131 along a direction perpendicular to the first surface 131 is the maximum depth of the recess 132. For another example, if the bottom surface 1322 of the recess 132 is an arcuate surface, the distance between the position of the bottom surface 1322 of the recess 132 farthest from the first surface 131 and the first surface 131 along a direction perpendicular to the first surface 131 is the maximum depth of the recess 132.

[0157] H1 / H2 can be any one of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or a range of values ​​between any two of them.

[0158] In the embodiment shown in Fig. 6 , H1 / H2 = 1. In the embodiment shown in Fig. 7 , H1 / H2<1.

[0159] In this embodiment, 0.1≤H1 / H2≤1, so that the thickness of the first conductive layer 5 is not too small, and the first conductive layer 5 is not easily damaged due to too small thickness, which is conducive to eliminating the discharge tip at the position where the side surface 1321 connects the first surface 131.

[0160] In some embodiments, 0.4≤H1 / H2≤1.

[0161] In this embodiment, H1 / H2 can be any one of 0.4, 0.42, 0.48, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, 0.62, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, 0.9, 0.92, 0.95, 0.98, 1, or a range between any two of them.

[0162] In this embodiment, 0.4≤H1 / H2≤1, further increasing the thickness of the first conductive layer 5 is beneficial to eliminating the discharge tip at the position where the side surface 1321 connects the first surface 131 and is beneficial to increasing the contact area between the first conductive layer 5 and the first wall portion 13.

[0163] In some embodiments, referring again to FIG. 6 and FIG. 7 , the first conductive layer 5 has a second surface 51 farthest from the bottom surface 1322 of the recess 132 , and the second surface 51 of the first conductive layer 5 is flush with the first surface 131 .

[0164] If there is no obvious height difference between the outer edge of the second surface 51 and the inner edge of the first surface 131 , it can be understood that the second surface 51 is flush with the first surface 131 .

[0165] As an example, the second surface 51 and the first surface 131 are located in the same plane.

[0166] In this embodiment, the second surface 51 of the first conductive layer 5 is flush with the first surface 131 , so that the second surface 51 and the first surface 131 are coplanar. The first wall portion 13 is more flat in the area where the recess 132 is provided, and the electric field strength distribution in this area is more uniform.

[0167] In some embodiments, the first conductive layer 5 is a conductive adhesive layer adhered to the first wall portion 13 .

[0168] The conductive adhesive layer can be formed by curing or drying a conductive adhesive. The conductive adhesive layer can include a resin substrate, conductive particles, and a dispersing additive. The resin substrate can include at least one of epoxy resin, acrylate resin, and polyurethane. The conductive particles can include powder made of at least one of gold, silver, copper, aluminum, zinc, iron, and nickel.

[0169] It should be noted that in the embodiment where the first conductive layer 5 contacts the bottom surface 1322 of the recess 132, the first conductive layer 5 is adhered to the side surface 1321 and the bottom surface 1322 of the recess 132; in the embodiment where a gap is set between the first conductive layer 5 and the bottom surface 1322 of the recess 132, the first conductive layer 5 is adhered to the side surface 1321 of the recess 132.

[0170] In this embodiment, the first conductive layer 5 is a conductive adhesive layer bonded to the first wall portion 13, ensuring a high connection strength between the first conductive layer 5 and the first wall portion 13 and preventing the first conductive layer 5 from falling out of the recess 132. During molding, the conductive adhesive is applied to the recess 132 to form the first conductive layer 5, making molding of the first conductive layer 5 easy.

[0171] In some embodiments, referring to Figures 8 and 9 , Figure 8 illustrates a schematic diagram of the connection between the first conductive layer 5, the second conductive layer 6, and the first wall 13 according to some embodiments of the present application; Figure 9 illustrates a schematic diagram of the connection between the first conductive layer 5, the second conductive layer 6, and the first wall 13 according to other embodiments of the present application. Battery cell 10 further includes a second conductive layer 6 having a third surface 61 that contacts first surface 131. First conductive layer 5 extends from third surface 61 toward the interior of recess 132, with second conductive layer 6 covering recess 132.

[0172] The second conductive layer 6 may be placed on the first surface 131 so that the third surface 61 contacts the first surface 131 , or the second conductive layer 6 may be fixedly connected to the first surface 131 so that the third surface 61 contacts the second surface 51 .

[0173] The second conductive layer 6 is made of a conductive material, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the second wall portion can be the same as or different from the material of the first conductive layer 5. The second conductive layer 6 and the first conductive layer 5 can be integrally formed or separately provided. If the second conductive layer 6 and the first conductive layer 5 are integrally formed, the second conductive layer 6 and the first conductive layer 5 are a single component, which can be referred to as a conductive member, and the second conductive layer 6 and the first conductive layer 5 are two parts of the conductive member. If the second conductive layer 6 and the first conductive layer 5 are separately provided, the second conductive layer 6 and the first conductive layer 5 are two components, which can be manufactured and connected separately.

[0174] As an example, the second conductive layer 6 includes an overlapping region overlapping with the first conductive layer 5 and a non-overlapping region not overlapping with the first conductive layer 5 , and the non-overlapping region is in contact with the first surface 131 .

[0175] In the embodiment shown in FIG. 8 , the first conductive layer 5 is in contact with the bottom surface 1322 of the recess 132 ; in the embodiment shown in FIG. 9 , a gap is provided between the first conductive layer 5 and the bottom surface 1322 of the recess 132 .

[0176] In this embodiment, the second conductive layer 6 covers the recess 132, thereby concealing the recess 132 and enhancing the appearance. Furthermore, the third surface 61 of the second conductive layer 6 contacts the first surface 131, and the first conductive layer 5 contacts the side surface 1321, thereby eliminating discharge spikes at the junction of the side surface 1321 and the first surface 131.

[0177] In some embodiments, referring again to FIG. 8 and FIG. 9 , the second conductive layer 6 covers the first surface 131 .

[0178] The second conductive layer 6 covers the first surface 131 , that is, the second conductive layer 6 completely shields the first surface 131 , and no portion of the first surface 131 is exposed.

[0179] In this embodiment, the second conductive layer 6 covers the first surface 131 , thereby reducing the risk of a discharge spike being formed between the outer peripheral surface of the second conductive layer 6 and the first surface 131 .

[0180] In some embodiments, referring again to FIG. 8 and FIG. 9 , the surface of the second conductive layer 6 facing away from the first surface 131 is a plane.

[0181] In this embodiment, the surface of the second conductive layer 6 facing away from the first surface 131 is not provided with a concavo-convex structure.

[0182] In this embodiment, the surface of the second conductive layer 6 away from the first surface 131 is planar, which reduces the risk of discharge spikes being formed due to the uneven surface of the second conductive layer 6 away from the first surface 131 .

[0183] 8 and 9 , in some embodiments, the maximum thickness of the first conductive layer 5 is H1, the maximum depth of the recess 132 is H2, and the maximum thickness of the second conductive layer 6 is H3, satisfying: 0.1≤(H1+H3) / H2≤20.

[0184] The thickness of the second conductive layer 6 at its thickest location is the maximum thickness of the second conductive layer 6. H1 + H3 is the maximum total thickness of the second conductive layer 6 and the first conductive layer 5. As an example, if the thickness of the second conductive layer 6 and the thickness of the first conductive layer 5 are both uniform, H1 + H3 is the total thickness of the second conductive layer 6 and the first conductive layer 5.

[0185] (H1+H3) / H2 can be any one of 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 points or a range of values ​​between any two of them.

[0186] In this embodiment, (H1+H3) / H2≥0.1, so that the total thickness of the first conductive layer 5 and the second conductive layer 6 is not too small, so that both have sufficient structural strength; (H1+H3) / H2≤20, so that the total thickness of the first conductive layer 5 and the second conductive layer 6 is not too large, reducing material consumption and lowering production costs.

[0187] In some embodiments, 1≤(H1+H3) / H2≤5.

[0188] In this embodiment, (H1+H3) / H2 can be any point value of 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, or a range value between any two of them.

[0189] In some embodiments, the first conductive layer 5 and the second conductive layer 6 are integrally formed, which has good structural strength and reduces the difficulty of forming the first conductive layer 5 and the second conductive layer 6.

[0190] In some embodiments, the second conductive layer 6 is a conductive adhesive layer adhered to the first wall portion 13 .

[0191] It can be understood that, in the embodiment where the first conductive layer 5 and the second conductive layer 6 are integrally formed, both the first conductive layer 5 and the second conductive layer 6 are conductive adhesive layers.

[0192] In this embodiment, the second conductive layer 6 is a conductive adhesive layer bonded to the first wall portion 13, ensuring a high connection strength between the second conductive layer 6 and the first wall portion 13 and preventing the second conductive layer 6 from separating from the first surface 131. During molding, the conductive adhesive is applied to the first surface 131 to form the second conductive layer 6, making molding of the second conductive layer 6 easier.

[0193] In some embodiments, the conductivity of the first wall portion 13 is Q1, the conductivity of the first conductive layer 5 is Q2, and 0.5≤Q2 / Q1≤1.5.

[0194] In this embodiment, Q2 / Q1 can be any one of 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, and 1.5, or a range of values ​​between any two of them.

[0195] It is understandable that the conductivity of the first wall portion 13 may be greater than the conductivity of the first conductive layer 5 , or less than the conductivity of the first conductive layer 5 , or equal to the conductivity of the first conductive layer 5 .

[0196] As an example, the second conductive layer 6 is made of the same material as the first conductive layer 5 , and the conductivity of the second conductive layer 6 is equal to the conductivity of the first conductive layer 5 .

[0197] In this embodiment, 0.5≤Q2 / Q1≤1.5, so that the conductivity of the first conductive layer 5 and the conductivity of the first wall portion 13 are not much different, and the conductivity of the first conductive layer 5 and the first wall portion 13 are relatively close, which is conducive to eliminating the discharge tip at the position where the side surface 1321 connects to the first surface 131.

[0198] In some embodiments, along the thickness direction Z of the first wall portion 13 , the first surface 131 faces the interior of the housing 1 ; or, the first surface 131 faces the exterior of the housing 1 .

[0199] As an example, in the embodiments shown in FIG. 6 to FIG. 9 , the first surface 131 faces the outside of the housing 1 .

[0200] If the first surface 131 faces the interior of the housing 1 , it can serve as the inner surface of the first wall 13 , with the recess 132 located on the inner side of the first wall 13 . This prevents the first conductive layer 5 from being exposed to the exterior of the housing 1 , protecting the first conductive layer 5 from damage. If the first surface 131 faces the exterior of the housing 1 , it can serve as the outer surface of the first wall 13 , with the recess 132 located on the outer side of the first wall 13 , facilitating placement of the first conductive layer 5 within the recess 132 .

[0201] In some embodiments, please continue to refer to FIG. 4 to FIG. 9 , the recess 132 is a groove 133 disposed on the first surface 131 , and the side surface of the groove 133 is a side surface 1321 .

[0202] The groove 133 can have various shapes, for example, a straight groove, an arc-shaped groove, an annular groove, a V-shaped groove, an H-shaped groove, etc. Taking the straight groove 133 as an example, the groove side surface of the groove 133 can include four side surfaces connected end to end, two side surfaces are arranged opposite to each other along the length direction of the groove 133, and the other two side surfaces are arranged opposite to each other along the width direction of the groove 133.

[0203] It can be understood that the bottom surface 1322 of the recess 132 is the bottom surface of the groove 133 .

[0204] In this embodiment, the provision of the first conductive layer 5 is helpful in eliminating the discharge tip at the position where the groove side surface of the groove 133 connects with the first surface 131 .

[0205] In some embodiments, referring to FIG. 4 to FIG. 9 , the first wall portion 13 forms a weak portion 134 in the region where the groove 133 is provided. The weak portion 134 is configured to be ruptured to release the pressure inside the battery cell 10 .

[0206] The weak portion 134 is the portion of the first wall 13 that remains after the groove 133 is formed. The weak portion 134 is the bottom wall of the groove 133. The strength of the weak portion 134 is weaker than the strength of the remaining portions of the first wall 13, making it more susceptible to damage. If the internal pressure of the battery cell 10 reaches a threshold during thermal runaway, the pressure relief portion can rupture to release the pressure within the battery cell 10.

[0207] When viewed along the thickness direction Z of the first wall portion 13, the extending direction of the weak portion 134 is the same as the extending direction of the groove 133. For example, the groove 133 is a linear groove extending along a straight track, while the weak portion 134 is a strip-shaped structure extending along the straight track. For another example, the groove 133 is an annular groove extending along a closed track, while the weak portion 134 is an annular structure extending along the closed track.

[0208] In this embodiment, the first wall portion 13 has a pressure relief function. When the battery cell 10 experiences thermal runaway, the weak portion 134 can rupture to release the pressure within the battery cell 10. With a gap between the first conductive layer 5 and the bottom surface 1322 of the recess 132, the first conductive layer 5 can more easily escape from the recess 133 during pressure relief, significantly impacting the detonation pressure of the battery cell 10.

[0209] In some embodiments, referring to FIG10 , FIG10 is a schematic structural diagram of the first wall portion 13 shown in FIG6 . The groove side surface of the groove 133 includes a first side surface 1334 and a second side surface 1335 disposed opposite to each other, and the first conductive layer 5 (not shown in FIG10 ) is in contact with both the first side surface 1334 and the second side surface 1335 .

[0210] The groove side surface of the groove 133 may include multiple side surfaces, and the first side surface 1334 and the second side surface 1335 may be any two opposite side surfaces among the multiple side surfaces. For example, the groove 133 is a linear groove, and the first side surface 1334 and the second side surface 1335 may be two opposite side surfaces of the groove 133 along the length direction, or two opposite side surfaces of the groove 133 along the width direction. In the embodiment shown in Figure 10, the first side surface 1334 and the second side surface 1335 are two opposite side surfaces of the groove 133 along the width direction. For another example, the groove 133 is an annular groove, and the first side surface 1334 and the second side surface 1335 are both annular surfaces connected end to end. The first side surface 1334 may surround the outer side of the second side surface 1335, and an annular groove may be formed between the first side surface 1334 and the second side surface 1335.

[0211] If the first side surface 1334 and the second side surface 1335 are both planes, the first side surface 1334 and the second side surface 1335 may be arranged in parallel, or at an acute angle or an obtuse angle.

[0212] As an example, the first conductive layer 5 is fixedly connected to the first side surface 1334 and the second side surface 1335 , so that the first conductive layer 5 is in contact with both the first side surface 1334 and the second side surface 1335 .

[0213] In this embodiment, both the first side surface 1334 and the second side surface 1335 are in contact with the first conductive layer 5 , which is beneficial for eliminating the discharge tip at the position where the first side surface 1334 connects to the first surface 131 and the discharge tip at the position where the second side surface 1335 connects to the first surface 131 .

[0214] In other embodiments, one of the first side surface 1334 and the second side surface 1335 may be in contact with the first conductive layer 5 , while the other may not be in contact with the first conductive layer 5 .

[0215] In some embodiments, please refer to Figures 11 and 12. Figure 11 is a schematic structural diagram of a battery cell 10 provided in other embodiments of the present application (the first conductive layer 5 is separated from the housing 1); Figure 12 is a partial view of the battery cell 10 shown in Figure 11. The groove 133 includes a first groove section 1331 and a second groove section 1332. The second groove section 1332 is connected to the first groove section 1331, and the extension direction of the second groove section 1332 intersects the extension direction of the first groove section 1331. The first conductive layer 5 includes a first conductive portion 52 and a second conductive portion 53. The first conductive portion 52 is located in the first groove section 1331 and contacts the groove side of the first groove section 1331. The second conductive portion 53 is located in the second groove section 1332 and contacts the groove side of the second groove section 1332.

[0216] The first slot segment 1331 and the second slot segment 1332 can be linear slots extending along a linear trajectory, or they can be non-linear slots extending along a non-linear trajectory, for example, arcuate slots extending along an arcuate trajectory. If the first slot segment 1331 and the second slot segment 1332 are linear slots, they can be arranged at an acute angle, a right angle, or an obtuse angle. The first slot segment 1331 and the second slot segment 1332 can form a V-shape, a T-shape, an X-shape, etc. In the embodiment shown in Figures 11 and 12, the first slot segment 1331 and the second slot segment 1332 form a V-shaped structure.

[0217] The first conductive portion 52 is the portion of the first conductive layer 5 located within the first slot segment 1331, and the second conductive portion 53 is the portion of the first conductive layer 5 located within the second slot segment 1332. As an example, the first conductive portion 52 and the second conductive portion 53 are integrally formed. The first conductive portion 52 is fixedly connected to the side surface of the first slot segment 1331 to achieve contact with the side surface of the first slot segment 1331, and the second conductive portion 53 is fixedly connected to the side surface of the second slot segment 1332 to achieve contact with the side surface of the second slot segment 1332.

[0218] It should be noted that in the embodiment where the first conductive layer 5 fills the recess 132, the first conductive portion 52 fills the first slot segment 1331, and the second conductive portion 53 fills the second slot segment 1332. In the embodiment where a gap is provided between the first conductive layer 5 and the bottom surface 1322 of the recess 132, a gap is provided between the first conductive portion 52 and the bottom surface of the first slot segment 1331, and a gap is provided between the second conductive portion 53 and the bottom surface of the second slot segment 1332.

[0219] In this embodiment, because the second slot section 1332 is connected to the first slot section 1331 and their extension directions intersect, the first wall portion 13 can partially flip open after the weak portion 134 ruptures along the first and second slot sections 1331, 1332. This effectively increases the pressure relief area of ​​the first wall portion 13 and improves the timely pressure relief of the battery cell 10 during thermal runaway. The first conductive portion 52 of the first conductive layer 5 is located within the first slot section 1331 and contacts the side surface of the first slot section 1331, facilitating the elimination of discharge spikes at the junction of the side surface of the first slot section 1331 and the first surface 131. The second conductive portion 53 of the first conductive layer 5 is located within the second slot section 1332 and contacts the side surface of the second slot section 1332, facilitating the elimination of discharge spikes at the junction of the side surface of the second slot section 1332 and the first surface 131. Furthermore, in embodiments in which the first conductive layer 5 is a conductive adhesive layer, the first conductive layer 5 provides minimal obstruction to the flipping of the first wall portion 13, significantly impacting the detonation pressure of the battery cell 10.

[0220] In some embodiments, referring to Figures 13 and 14, Figure 13 is a cross-sectional view along line BB in Figure 12, and Figure 14 is a cross-sectional view along line CC in Figure 12. Along the width direction of the first slot segment 1331, the slot side surfaces of the first slot segment 1331 include a first side surface 1334 and a second side surface 1335 disposed opposite each other, both of which are in contact with the first conductive portion 52; and / or, along the width direction of the second slot segment 1332, the slot side surfaces of the second slot segment 1332 include a third side surface 1336 and a fourth side surface 1337 disposed opposite each other, both of which are in contact with the second conductive portion 53.

[0221] The first side surface 1334 and the second side surface 1335 are two opposing side surfaces along the width direction of the first slot segment 1331. The first conductive portion 52 can be fixedly connected to the first side surface 1334 and the second side surface 1335 so that both the first side surface 1334 and the second side surface 1335 are in contact with the first conductive portion 52. The first side surface 1334 and the second side surface 1335 can be arranged in parallel or at an acute or obtuse angle.

[0222] The third side surface 1336 and the fourth side surface 1337 are two side surfaces disposed opposite each other along the width direction of the second slot segment 1332. The second conductive portion 53 can be fixedly connected to the third side surface 1336 and the fourth side surface 1337 so that both the third side surface 1336 and the fourth side surface 1337 are in contact with the second conductive portion 53. The third side surface 1336 and the fourth side surface 1337 can be disposed in parallel or at an acute or obtuse angle.

[0223] In this embodiment, the first side surface 1334 and the second side surface 1335 are in contact with the first conductive portion 52, which helps eliminate discharge spikes at the locations where the first side surface 1334 connects to the first surface 131 and where the second side surface 1335 connects to the first surface 131. The third side surface 1336 and the fourth side surface 1337 are in contact with the second conductive portion 53, which helps eliminate discharge spikes at the locations where the third side surface 1336 connects to the first surface 131 and where the fourth side surface 1337 connects to the first surface 131.

[0224] In some embodiments, please refer to Figures 15 and 16. Figure 15 is a schematic structural diagram of a battery cell 10 provided in some further embodiments of the present application (the first conductive layer 5 is separated from the housing 1); Figure 16 is a partial view of the battery cell 10 shown in Figure 15. The groove 133 may further include a third groove section 1333, wherein the first groove section 1331 and the third groove section 1333 are disposed opposite each other, and the second groove section 1332 connects the first groove section 1331 and the third groove section 1333. The first conductive layer 5 may further include a third conductive portion 54, which is located within the third groove section 1333 and contacts the groove side surface of the third groove section 1333.

[0225] The third slot segment 1333 can be a linear slot extending along a linear trajectory, or a non-linear slot extending along a non-linear trajectory. For example, the third slot segment 1333 is an arcuate slot extending along an arcuate trajectory. If the first slot segment 1331, the second slot segment 1332, and the third slot segment 1333 are all linear slots, the first slot segment 1331 and the third slot segment 1333 can be arranged parallel to each other, or at an acute or obtuse angle. The first slot segment 1331 and the second slot segment 1332 can be arranged perpendicularly, or at an acute or obtuse angle. The third slot segment 1333 and the second slot segment 1332 can be arranged perpendicularly, or at an acute or obtuse angle.

[0226] The connection position between the second slot segment 1332 and the first slot segment 1331 can be located at the middle position of the first slot segment 1331 in the extension direction, or can be offset from the middle position of the first slot segment 1331 in the extension direction. The connection position between the second slot segment 1332 and the third slot segment 1333 can be located at the middle position of the third slot segment 1333 in the extension direction, or can be offset from the middle position of the third slot segment 1333 in the extension direction. The first slot segment 1331, the second slot segment 1332, and the third slot segment 1333 can form various shapes, such as a U-shape, an N-shape, or an H-shape.

[0227] As an example, in Figures 15 and 16, the first slot segment 1331, the second slot segment 1332, and the third slot segment 1333 are all linear slots. The first slot segment 1331 is parallel to the third slot segment 1333. Both the first slot segment 1331 and the third slot segment 1333 are perpendicular to the second slot segment 1332. One end of the second slot segment 1332 is connected to the middle position of the first slot segment 1331 in the extension direction, and the other end of the second slot segment 1332 is connected to the middle position of the third slot segment 1333 in the extension direction. The first slot segment 1331, the second slot segment 1332, and the third slot segment 1333 form an H-shaped structure.

[0228] The third conductive portion 54 is a component of the first conductive layer 5 located within the third slot segment 1333. The second conductive portion 53 connects the first conductive portion 52 and the third conductive portion 54. As an example, the first conductive portion 52, the second conductive portion 53, and the third conductive portion 54 are integrally formed, and the third conductive portion 54 is fixedly connected to the side surface of the third slot segment 1333 to achieve contact between the third conductive portion 54 and the side surface of the third slot segment 1333.

[0229] It should be noted that in the embodiment where the first conductive layer 5 fills the recess 132, the third conductive portion 54 fills the third slot segment 1333. In the embodiment where a gap is provided between the first conductive layer 5 and the bottom surface 1322 of the recess 132, a gap is provided between the third conductive portion 54 and the bottom surface of the third slot segment 1333.

[0230] In this embodiment, the area defined by the first slot segment 1331, the second slot segment 1332, and the third slot segment 1333 is larger, resulting in a larger area for the portion of the first wall portion 13 that is flipped open after the weak portion 134 ruptures along the first slot segment 1331, the second slot segment 1332, and the third slot segment 1333, further increasing the pressure relief area of ​​the first wall portion 13. The third conductive portion 54 of the first conductive layer 5 is located within the third slot segment 1333 and contacts the slot side surface of the third slot segment 1333, which helps eliminate discharge spikes at the location where the slot side surface of the third slot segment 1333 connects to the first surface 131.

[0231] In some embodiments, referring to FIG17 , FIG17 is a DD cross-sectional view in FIG16 . Along the width direction of the third slot segment 1333 , the slot side surfaces of the third slot segment 1333 include a fifth side surface 1338 and a sixth side surface 1339 that are oppositely disposed. Both the fifth side surface 1338 and the sixth side surface 1339 are in contact with the third conductive portion 54 .

[0232] The fifth side surface 1338 and the sixth side surface 1339 are two opposing side surfaces along the width direction of the third slot segment 1333. The third conductive portion 54 can be fixedly connected to the fifth side surface 1338 and the sixth side surface 1339 so that both the fifth side surface 1338 and the sixth side surface 1339 are in contact with the third conductive portion 54. The fifth side surface 1338 and the sixth side surface 1339 can be arranged in parallel or at an acute or obtuse angle.

[0233] In this embodiment, the fifth side surface 1338 and the sixth side surface 1339 are both in contact with the third conductive portion 54 , which helps eliminate discharge tips at the connection position between the fifth side surface 1338 and the first surface 131 and the connection position between the sixth side surface 1339 and the first surface 131 .

[0234] In some embodiments, please refer to FIG18 , which is a schematic structural diagram of a battery cell 10 provided in some other embodiments of the present application (the first conductive layer 5 is separated from the housing 1 ). The groove 133 is a slot extending along a closed track.

[0235] The closed track can be circular, elliptical, polygonal, etc. The polygon can be triangular, quadrilateral, pentagonal, hexagonal, etc. The groove formed along the closed track is an annular groove. It is understandable that the groove 133 is an annular groove, and the first conductive layer 5 can also be set to be annular accordingly.

[0236] After the weak portion 134 is cracked along the extension direction of the groove 133, the area of ​​the first wall portion 13 defined by the groove 133 can be detached and opened as a whole. The opening of this area is not easily affected by the first conductive layer 5, the pressure relief is more timely, and the pressure relief area is larger.

[0237] In some embodiments, please refer to Figures 19 to 22. Figure 19 is a schematic structural diagram of a battery cell 10 provided in another embodiment of the present application (the first conductive layer 5 is separated from the shell 1), Figure 20 is a partial view of the battery cell 10 shown in Figure 19; Figure 21 is an EE cross-sectional view in Figure 20; and Figure 22 is a schematic diagram of the connection between the first conductive layer 5, the second conductive layer 6 and the first wall portion 13 provided in some other embodiments of the present application. The first wall portion 13 includes a wall body 135 and a protrusion 136. The wall body 135 has a fourth surface 1351. The protrusion 136 is provided on the fourth surface 1351. The outer peripheral surface of the protrusion 136 and the fourth surface 1351 together define a recess 132. The recess 132 surrounds the protrusion 136. The outer peripheral surface of the protrusion 136 is a side surface 1321, and the end surface of the protrusion 136 away from the fourth surface 1351 is the first surface 131.

[0238] Fourth surface 1351 of wall body 135 serves as bottom surface 1322 of recess 132. After protrusions 136 are provided on fourth surface 1351 of wall body 135, recess 132 is formed in the first wall portion 13 corresponding to the area of ​​fourth surface 1351 where protrusions 136 are not provided. In embodiments where first conductive layer 5 fills recess 132, first conductive layer 5 covers the area of ​​fourth surface 1351 where protrusions 136 are not provided.

[0239] In the embodiment shown in FIG. 21 , the first conductive layer 5 has a second surface 51 farthest from the bottom surface 1322 (fourth surface 1351 ) of the recess 132 , and the second surface 51 is flush with the first surface 131 .

[0240] In the embodiment shown in FIG22 , the battery cell 10 includes a second conductive layer 6, a first conductive layer 5 protruding from a third surface 61 of the second conductive layer 6, the third surface 61 contacting the first surface 131 of the protrusion 136, and the second conductive layer 6 covering the recess 132. The first conductive layer 5 and the second conductive layer 6 jointly define a groove that matches the protrusion 136, and the protrusion 136 is accommodated in the groove.

[0241] In this embodiment, the outer peripheral surface of the protrusion 136 and the fourth surface 1351 jointly define the concave portion 132 . The arrangement of the first conductive layer 5 in the concave portion 132 helps eliminate the discharge tip at the position where the outer peripheral surface of the protrusion 136 connects with the first surface 131 .

[0242] In some embodiments, along the circumference of the recess 132 , the first conductive layer 5 is in contact with the side surface 1321 throughout the entire circumference.

[0243] It can be understood that the surface of the first conductive layer 5 connected end to end is in contact with the side surface 1321 .

[0244] As an example, as shown in Figures 4-6 and Figures 19-22, taking the side surface 1321 as a rectangle as an example, the side surface 1321 includes four side surfaces connected end to end along the circumference of the recess 132. The first conductive layer 5 is in contact with the side surface 1321 throughout the entire circumference, which means that the first conductive layer 5 is in contact with all four side surfaces of the side surface 1321.

[0245] In this embodiment, the first conductive layer 5 is in contact with the side surface 1321 throughout its entire circumference, which can further reduce the risk of tip discharge at the connection point between the side surface 1321 and the first surface 131 in a high-voltage environment.

[0246] In some embodiments, please refer to Figures 23 and 24. Figure 23 is an exploded view of the housing 1 provided in some embodiments of the present application; Figure 24 is an exploded view of the housing 1 provided in other embodiments of the present application. The housing 1 includes a shell 11 and an end cap 12. The shell 11 has an opening, and the end cap 12 closes the opening. The end cap 12 is a first wall 13; and / or at least one wall of the shell 11 is a first wall 13.

[0247] The housing 1 may be cylindrical or prismatic, etc. As an example, in the embodiments shown in Figures 23 and 24 , the housing 1 is prismatic, specifically, the housing 1 is in the shape of a cuboid.

[0248] The housing 11 may include multiple walls that define the interior space of the housing 11. If at least one wall in the housing 11 is the first wall 13, it is understood that one or more walls may be the first wall 13. In the embodiment shown in FIG23 , the wall of the housing 11 opposite the end cap 12 is the first wall 13. In the embodiment shown in FIG24 , the end cap 12 is the first wall 13.

[0249] In some embodiments, please refer to FIG25 , which is an exploded view of the housing 1 provided in some other embodiments of the present application. The first wall portion 13 is provided with an insulating member 14 , and the first surface 131 is provided facing the insulating member 14 .

[0250] The insulating member 14 is made of insulating material, such as rubber, plastic, etc.

[0251] It should be noted that, in an embodiment in which only the first conductive layer 5 is provided on the first wall portion 13, the insulating member 14 can be provided on the first surface 131; in an embodiment in which the first conductive layer 5 and the second conductive layer 6 are provided on the first wall portion 13, if the second conductive layer 6 covers the first surface 131, the insulating member 14 can be provided on the surface of the second conductive layer 6 facing away from the first surface 131.

[0252] In embodiments where the first surface 131 faces the interior of the housing 1, the insulating member 14 is disposed on the side of the first wall 13 facing the electrode assembly 2. The insulating member 14 serves to insulate and isolate the first wall 13 from the electrode assembly 2. For example, using the end cap 12 as the first wall 13, the insulating member 14 may be a lower plastic member disposed on the inner side of the end cap 12.

[0253] In embodiments where the first surface 131 faces the exterior of the housing 1, the insulating member 14 is disposed on a side of the first wall 13 facing away from the electrode assembly 2. The insulating member 14 serves to insulate and isolate the first wall 13 from external components. For example, if at least one wall of the housing 11 is the first wall 13, the insulating member 14 may be an insulating film covering the exterior of the housing 11. For another example, as shown in FIG25 , if the end cap 12 is the first wall 13, the insulating member 14 may be an insulating patch disposed on the exterior of the end cap 12.

[0254] In this embodiment, the provision of the insulating member 14 can achieve insulation between the first wall portion 13 and other components (external components, electrode assembly 2, etc.). Since the first conductive layer 5 is provided in the recess 132 of the first wall portion 13, the electric field distribution in the recess 132 region is improved, and the electric field strength distribution is more uniform, reducing the risk of insulation failure caused by breakdown of the insulating member 14 due to tip discharge.

[0255] An embodiment of the present application provides a battery 100 , comprising the battery cell 10 provided in any one of the above embodiments.

[0256] An embodiment of the present application provides an electrical device, comprising the battery cell 10 provided in any one of the above embodiments.

[0257] In addition, an embodiment of the present application also provides a battery cell 10, which includes an outer shell 1 and an electrode assembly 2. The outer shell 1 is a rectangular parallelepiped, and includes a shell 11 and an end cover 12. The end cover 12 closes the opening of the shell 11. The wall of the shell 11 opposite to the end cover 12 is a first wall 13. The surface of the first wall 13 facing away from the electrode assembly 2 is a first surface 131. The first wall 13 is provided with a groove 133. The groove side of the groove 133 is connected to the first surface 131. A first conductive layer 5 is provided in the groove 133. The first conductive layer 5 is in contact with the groove side of the groove 133. The first conductive layer 5 has a second surface 51 that is farthest from the bottom of the groove 133. The second surface 51 is flush with the first surface 131. The first conductive layer 5 is a conductive adhesive layer that fills the groove 133.

[0258] The first wall portion 13 forms a weak portion 134 in the region where the groove 133 is located. The weak portion 134 is configured to rupture to release pressure within the battery cell 10. The groove 133 includes a first groove section 1331, a second groove section 1332, and a third groove section 1333. The first groove section 1331 is disposed opposite the third groove section 1333, and the second groove section 1332 connects the first groove section 1331 and the third groove section 1333. The first groove section 1331, the second groove section 1332, and the third groove section 1333 form an H-shaped structure. The first conductive layer 5 includes a first conductive portion 52, a second conductive portion 53, and a third conductive portion 54. The first conductive portion 52, the second conductive portion 53, and the third conductive portion 54 are located within the first groove section 1331, the second groove section 1332, and the third groove section 1333, respectively.

[0259] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0260] The above embodiments are intended only to illustrate the technical solutions of this application and are not intended to limit this application. Those skilled in the art will appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application are intended to be within the scope of protection of this application.

Claims

1. A battery cell, comprising: The housing comprises a first wall portion, the first wall portion has a first surface, the first wall portion is provided with a recessed portion, and the recessed portion has a side surface connected to the first surface; The first conductive layer is accommodated in the concave portion, and the first conductive layer is in contact with the side surface.

2. The battery cell according to claim 1, wherein: The first conductive layer extends from the first surface into the recess.

3. The battery cell according to claim 1 or 2, wherein: The recess has a bottom surface facing the first conductive layer, and the bottom surface is connected to the side surface; Wherein, the first conductive layer contacts the bottom surface.

4. The battery cell according to any one of claims 1 to 3, wherein: The first conductive layer fills the recess.

5. The battery cell according to claim 1 or 2, wherein: The recess has a bottom surface facing the first conductive layer, and the bottom surface is connected to the side surface; Wherein, a gap is set between the first conductive layer and the first surface.

6. The battery cell according to any one of claims 1 to 5, wherein: The maximum thickness of the first conductive layer is H1, and the maximum depth of the recess is H2, satisfying: 0.1≤H1 / H2≤1.

7. The battery cell according to claim 6, wherein: 0.4≤H1 / H2≤1.

8. The battery cell according to any one of claims 1 to 7, wherein: The first conductive layer has a second surface farthest from the bottom surface of the recess, and the second surface is flush with the first surface.

9. The battery cell according to any one of claims 1 to 8, wherein: The first conductive layer is a conductive adhesive layer bonded to the first wall portion.

10. The battery cell according to any one of claims 1 to 7 and 9, wherein: The battery cell further includes a second conductive layer having a third surface, the third surface being in contact with the first surface, the first conductive layer extending from the third surface toward the inside of the recess, and the second conductive layer covering the recess.

11. The battery cell according to claim 10, wherein: The second conductive layer covers the first surface.

12. The battery cell according to claim 10 or 11, wherein: A surface of the second conductive layer facing away from the first surface is a plane.

13. The battery cell according to any one of claims 10 to 12, wherein: The maximum thickness of the first conductive layer is H1, the maximum depth of the recess is H2, and the maximum thickness of the second conductive layer is H3, satisfying: 0.1≤(H1+H3) / H2≤20.

14. The battery cell according to claim 13, wherein: 1≤(H1+H3) / H2≤5.

15. The battery cell according to any one of claims 10 to 14, wherein: The first conductive layer and the second conductive layer are integrally formed.

16. The battery cell according to any one of claims 10 to 15, wherein: The second conductive layer is a conductive adhesive layer bonded to the first wall portion.

17. The battery cell according to any one of claims 1 to 16, wherein: The electrical conductivity of the first wall portion is Q1, the electrical conductivity of the first conductive layer is Q2, and 0.5≤Q2 / Q1≤1.

5.

18. The battery cell according to any one of claims 1 to 17, wherein: Along the thickness direction of the first wall portion, the first surface faces the interior of the housing; or, the first surface faces the exterior of the housing.

19. The battery cell according to any one of claims 1 to 18, wherein: The recessed portion is a groove disposed on the first surface, and a groove side surface of the groove is the side surface.

20. The battery cell according to claim 19, wherein: The first wall portion forms a weak portion in a region where the groove is provided, and the weak portion is configured to be broken to release pressure inside the battery cell.

21. The battery cell according to claim 20, wherein: The groove side surface of the groove includes a first side surface and a second side surface that are opposite to each other, and the first side surface and the second side surface are both in contact with the first conductive layer.

22. The battery cell according to claim 20 or 21, wherein: The groove comprises a first groove section and a second groove section, the second groove section is connected to the first groove section, and an extension direction of the second groove section intersects with an extension direction of the first groove section; The first conductive layer includes a first conductive portion and a second conductive portion. The first conductive portion is located in the first slot segment and contacts the slot side surface of the first slot segment. The second conductive portion is located in the second slot segment and contacts the slot side surface of the second slot segment.

23. The battery cell according to claim 22, wherein: Along the width direction of the first slot segment, the slot side surfaces of the first slot segment include a first side surface and a second side surface that are relatively arranged, and the first side surface and the second side surface are both in contact with the first conductive portion; and / or, along the width direction of the second slot segment, the slot side surfaces of the second slot segment include a third side surface and a fourth side surface that are relatively arranged, and the third side surface and the fourth side surface are both in contact with the second conductive portion.

24. The battery cell according to claim 22 or 23, wherein: The groove further includes a third groove section, the first groove section is arranged opposite to the third groove section, and the second groove section connects the first groove section and the third groove section; The first conductive layer further includes a third conductive portion, which is located in the third slot segment and in contact with a slot side surface of the third slot segment.

25. The battery cell according to claim 24, wherein: Along the width direction of the third slot segment, the slot side surface of the third slot segment includes a fifth side surface and a sixth side surface that are arranged opposite to each other, and both the fifth side surface and the sixth side surface are in contact with the third conductive portion.

26. The battery cell according to claim 20 or 21, wherein: The groove is a slot extending along a closed track.

27. The battery cell according to any one of claims 1 to 18, wherein: The first wall portion comprises: a wall body having a fourth surface; The convex portion is arranged on the fourth surface, the outer peripheral surface of the convex portion and the fourth surface jointly define the concave portion, and the concave portion surrounds the convex portion. The periphery of the convex portion is the side surface, and the end surface of the convex portion away from the fourth surface is the first surface.

28. The battery cell according to any one of claims 1 to 27, wherein: The first conductive layer is in contact with the side surface over the entire circumference of the recess.

29. The battery cell according to any one of claims 1 to 28, wherein: The housing comprises: a housing having an opening; an end cap for closing the opening; Wherein, the end cover is the first wall portion; and / or, at least one wall portion in the shell is the first wall portion.

30. The battery cell according to any one of claims 1 to 29, wherein: The first wall portion is provided with an insulating member, and the first surface is arranged facing the insulating member.

31. The battery cell according to claim 30, wherein: The battery cell further includes an electrode assembly, and the electrode assembly is accommodated in the housing; The first surface faces the interior of the shell, and the insulating member is arranged on a side of the first wall portion facing the electrode assembly; or, the first surface faces the exterior of the shell, and the insulating member is arranged on a side of the first wall portion away from the electrode assembly.

32. A battery comprising the battery cell according to any one of claims 1 to 31.

33. An electrical device comprising the battery cell according to any one of claims 1 to 31.

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