Battery monomer, battery and electric equipment

Abstract

The utility model provides a battery monomer, a battery and electric equipment. The battery monomer comprises a shell, an end cover, an electrode assembly and a pressure relief mechanism, the shell is provided with a containing space with an opening in one end, the end cover is connected to the shell and seals the opening, and the end cover is provided with a pressure relief hole. The electrode assembly is accommodated in the accommodation space. The pressure relief mechanism is arranged on the end cover and seals the pressure relief hole, and the pressure relief mechanism is configured to be capable of releasing the pressure in the battery monomer. Wherein the pressure relief mechanism is made of steel or nickel, the end cover is made of steel, and the pressure relief mechanism is connected with the end cover in a welded mode. The pressure relief mechanism is made of steel or nickel, and the end cover is made of steel, so that the structural strength of the end cover and the pressure relief mechanism can be improved, the risk that the end cover and the pressure relief mechanism deform due to stress is reduced, the risk that the pressure relief mechanism opens a valve in advance for pressure relief is reduced, the service life of the single battery is prolonged, and the reliability of the single battery is improved. In addition, the pressure relief mechanism made of the steel material or the nickel material is easy to weld with the end cover made of the steel material.

Description

Technical Field

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

[0002] Batteries are widely used in new energy applications, such as electric vehicles and new energy vehicles. These have become a new trend in the automotive industry. The development of battery technology requires consideration of multiple design factors, including performance parameters such as battery life, energy density, discharge capacity, and charge / discharge rate. Furthermore, battery reliability must be considered. However, current battery reliability is relatively poor. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a battery cell, a battery, and an electrical device, which are intended to improve the problem of poor reliability of batteries in related technologies.

[0004] In a first aspect, an embodiment of the present application provides a battery cell, which includes a shell, an end cover, an electrode assembly and a pressure relief mechanism, wherein the shell has a accommodating space with an opening at one end; the end cover is connected to the shell and closes the opening, and the end cover is provided with a pressure relief hole; the electrode assembly is accommodated in the accommodating space; the pressure relief mechanism is provided on the end cover and closes the pressure relief hole, and the pressure relief mechanism is configured to release the pressure inside the battery cell; wherein the material of the pressure relief mechanism includes steel or nickel, the material of the end cover includes steel, and the pressure relief mechanism is welded to the end cover.

[0005] In the above technical solution, the pressure relief mechanism of the battery cell is provided on the end cover. During manufacturing, the pressure relief mechanism can be connected to the end cover first, and then the end cover can be connected to the shell, which is conducive to simplifying manufacturing and reducing manufacturing costs. In addition, the space outside the end cover is relatively large, which can facilitate the pressure relief of the pressure relief mechanism. By making the material of the pressure relief mechanism include steel or nickel, and the material of the end cover include steel, on the one hand, the structural strength of the end cover and the pressure relief mechanism can be effectively improved, and the risk of deformation of the end cover and the pressure relief mechanism due to force is reduced, which is conducive to reducing the risk of the pressure relief mechanism opening the valve to relieve pressure prematurely, and is conducive to improving the service life and reliability of the battery cell. On the other hand, the pressure relief mechanism made of steel or nickel is easier to weld with the end cover made of steel, which is conducive to reducing the phenomenon of welding cracks between the pressure relief mechanism and the end cover, thereby reducing the risk of leakage of the battery cell and improving the reliability of the battery cell.

[0006] As an optional technical solution of the embodiment of the present application, the pressure relief mechanism and the end cover are both made of steel.

[0007] In the above technical solution, steel has high strength and low cost. By making the pressure relief mechanism and the end cap both made of steel, the structural strength of the end cap and the pressure relief mechanism can be improved, and the risk of deformation of the end cap and the pressure relief mechanism due to stress can be reduced. This helps reduce the risk of the pressure relief mechanism opening the valve prematurely to relieve pressure, and helps improve the service life and reliability of the battery cell. In addition, the pressure relief mechanism and the end cap are made of the same material, which makes it easier to weld the pressure relief mechanism and the end cap, which helps reduce the phenomenon of welding cracks between the pressure relief mechanism and the end cap, thereby reducing the risk of leakage of the battery cell and improving the reliability of the battery cell.

[0008] As an optional technical solution of the embodiment of the present application, the pressure relief mechanism and the end cover are both made of 304 stainless steel.

[0009] In the above technical solution, 304 stainless steel has advantages such as corrosion resistance, high temperature resistance, and good processing performance. The pressure relief mechanism and end caps made of 304 stainless steel have high strength, which can reduce the risk of deformation of the end caps and pressure relief mechanism due to stress, thereby reducing the risk of premature valve opening and pressure relief of the pressure relief mechanism, thereby improving the service life and reliability of the battery cells. In addition, the pressure relief mechanism and end caps made of 304 stainless steel are not easy to corrode, which helps to extend the service life of the battery cells.

[0010] As an optional technical solution of the embodiment of the present application, the pressure relief mechanism is in a sheet shape, and the thickness of the pressure relief mechanism is H1, which satisfies: 0.05mm≤H1≤0.5mm.

[0011] In the above technical solution, when H1 ≥ 0.05mm, the pressure relief mechanism is thicker, providing greater structural strength, reducing the risk of deformation due to stress, and thus improving the battery cell's service life and reliability. When H1 ≤ 0.5mm, the pressure relief mechanism is not excessively thick, helping to control the manufacturing cost of the battery cell. Therefore, when 0.05mm ≤ H1 ≤ 0.5mm, the battery cell's service life, reliability, and manufacturing cost are balanced.

[0012] As an optional technical solution of the embodiment of the present application, 0.05mm≤H1≤0.3mm.

[0013] In the above technical solution, when H1 ≥ 0.05mm, the pressure relief mechanism is thicker, providing greater structural strength, reducing the risk of deformation due to stress, and thus improving the battery cell's service life and reliability. When H1 ≤ 0.3mm, the pressure relief mechanism is not excessively thick, further helping to control the manufacturing cost of the battery cell. Therefore, when 0.05mm ≤ H1 ≤ 0.3mm, a better balance between battery cell service life, reliability, and manufacturing cost is achieved.

[0014] As an optional technical solution of an embodiment of the present application, the pressure relief mechanism is provided with a pressure relief groove, and the pressure relief mechanism is configured to split along at least a portion of the pressure relief groove when the battery cell is depressurized.

[0015] In the above technical solution, a weak portion is formed on the pressure relief mechanism by providing a pressure relief groove on the pressure relief mechanism. When the battery cell releases pressure, the pressure relief mechanism is cracked along at least a portion of the weak portion, which is simple, convenient and low-cost.

[0016] As an optional technical solution of an embodiment of the present application, the residual thickness of the pressure relief groove is D, which satisfies: 0.01mm≤D≤0.3mm.

[0017] In the above technical solution, when D ≥ 0.01mm, the residual thickness of the pressure relief groove is relatively large, which helps reduce the risk of the pressure relief mechanism opening the valve to release pressure prematurely and improves the service life and reliability of the battery cell. When D ≤ 0.3mm, the residual thickness of the pressure relief groove is not too large, allowing the pressure relief mechanism to open and release pressure in a timely manner when the battery cell thermal runaway occurs, which helps improve the timeliness of the pressure relief mechanism's pressure relief. Therefore, when 0.01mm ≤ D ≤ 0.3mm, the service life, reliability, and timeliness of pressure relief of the battery cell can be taken into account.

[0018] As an optional technical solution of the embodiment of the present application, 0.015mm≤D≤0.15mm.

[0019] In the above technical solution, when D ≥ 0.015mm, the residual thickness of the pressure relief groove is greater, which is more conducive to reducing the risk of the pressure relief mechanism opening the valve to release pressure prematurely, thereby improving the service life and reliability of the battery cell. When D ≤ 0.15mm, the residual thickness of the pressure relief groove is not too large, allowing the pressure relief mechanism to open and release pressure more promptly when the battery cell thermal runaway occurs, which is conducive to improving the timeliness of the pressure relief mechanism's pressure relief. Therefore, when 0.015mm ≤ D ≤ 0.15mm, it is possible to better balance the service life, reliability, and timeliness of pressure relief of the battery cell.

[0020] As an optional technical solution of the embodiment of the present application, the thickness of the end cover is H2, which satisfies: 0.2mm≤H2≤3mm.

[0021] In the above technical solution, when H2 ≥ 0.2mm, the end cap thickness is greater, providing higher structural strength, reducing the risk of deformation due to stress, and thus reducing the risk of premature valve opening and pressure relief by the pressure relief mechanism, thereby improving the service life and reliability of the battery cell. When H2 ≤ 3mm, the end cap thickness is not excessive, which helps control the manufacturing cost of the battery cell. Therefore, when 0.2mm ≤ H2 ≤ 3mm, the service life, reliability, and manufacturing cost of the battery cell can be balanced.

[0022] As an optional technical solution of the embodiment of the present application, 0.3mm≤H2≤2.5mm.

[0023] In the above technical solution, when H2 ≥ 0.3mm, the end cap thickness is greater, providing greater structural strength, and reducing the risk of deformation due to stress. This helps reduce the risk of the pressure relief mechanism prematurely opening the valve to release pressure, thereby improving the service life and reliability of the battery cell. When H2 ≤ 2.5mm, the end cap thickness is not excessive, which is more conducive to controlling the manufacturing cost of the battery cell. Therefore, when 0.3mm ≤ H2 ≤ 2.5mm, the service life, reliability, and manufacturing cost of the battery cell are better balanced.

[0024] As an optional technical solution of the embodiment of the present application, the pressure relief mechanism is located at one end of the pressure relief hole facing the shell.

[0025] In the above technical solution, when the pressure relief mechanism is arranged at the end of the pressure relief hole facing the shell, the risk of the pressure relief mechanism being affected by external force is smaller, which is beneficial to reducing the risk of the pressure relief mechanism opening the valve to relieve pressure prematurely and is beneficial to improving the service life and reliability of the battery cell.

[0026] As an optional technical solution of an embodiment of the present application, the end cover has a first surface facing the shell, the first surface is provided with a groove, and the groove is connected to the pressure relief hole; the pressure relief mechanism is partially accommodated in the groove, and the part of the pressure relief mechanism accommodated in the groove is welded to the end cover.

[0027] In the above technical solution, a groove is provided on the end cap to partially accommodate the pressure relief mechanism. On the one hand, the groove can position the pressure relief mechanism, thereby facilitating welding the pressure relief mechanism to the end cap. On the other hand, the bottom wall of the groove can support the pressure relief mechanism, making it difficult to weld through when welding the pressure relief mechanism and the end cap.

[0028] As an optional technical solution of an embodiment of the present application, the part of the pressure relief mechanism accommodated in the groove has a second surface facing the shell, and along the thickness direction of the end cover, the distance between the first surface and the second surface is L, satisfying: L≤0.15mm.

[0029] In the above technical solution, by ensuring that the height difference between the first surface and the second surface along the thickness direction of the end cover is less than or equal to 0.15 mm, the welding quality of the pressure relief mechanism and the end cover is improved.

[0030] As an optional technical solution of an embodiment of the present application, the first surface and the second surface are flush.

[0031] In the above technical solution, when the first surface and the second surface are flush, the pressure relief mechanism and the end cover can be welded by butt welding. The heat generated by butt welding is relatively small, which is beneficial to reducing the risk of cracking of the pressure relief mechanism.

[0032] As an optional technical solution of an embodiment of the present application, the end cover includes a main body and a support portion, the pressure relief hole is arranged on the support portion, and the support portion and the main body jointly define a groove connected to the pressure relief hole; the pressure relief mechanism is partially accommodated in the groove and is against the support portion, and the pressure relief mechanism is welded to the main body.

[0033] In the above technical solution, the support portion and the main body jointly define a groove, which accommodates the pressure relief mechanism. On the one hand, the groove can position the pressure relief mechanism, thereby facilitating welding the pressure relief mechanism to the main body. On the other hand, the support portion can support the pressure relief mechanism, making it difficult to weld through when welding the pressure relief mechanism and the main body.

[0034] As an optional technical solution of the embodiment of the present application, the support portion and the main body portion are integrally formed.

[0035] In the above technical solution, by integrally forming the support portion and the main body portion, the end cover has better structural strength, which is beneficial to improving the reliability of the battery cell.

[0036] As an optional technical solution of the embodiment of the present application, along the thickness direction of the end cover, the thickness of the support portion is H3, satisfying: 0.2mm≤H3≤3mm.

[0037] In the above technical solution, when H3 ≥ 0.2mm, the thickness of the support portion is relatively large, which can reduce the risk of weld penetration when welding the pressure relief mechanism and the main body. When H3 ≤ 3mm, the thickness of the support portion is not too large. On the one hand, it can reduce the space occupied by the battery cell or the internal battery, thereby improving the battery's energy density. On the other hand, it can reduce material consumption and lower the cost of the battery cell. Therefore, when 0.2mm ≤ H3 ≤ 3mm, it can both reduce the risk of weld penetration during welding and improve the battery's energy density.

[0038] As an optional technical solution of the embodiment of the present application, 0.3mm≤H3≤2.5mm.

[0039] In the above technical solution, when H3 ≥ 0.3mm, the thickness of the support portion is greater, which can further reduce the risk of weld penetration when welding the pressure relief mechanism and the main body. When H3 ≤ 2.5mm, the thickness of the support portion is not too large. On the one hand, it can reduce the space occupied by the battery cell or the internal battery, thereby improving the battery's energy density. On the other hand, it can reduce material consumption and reduce the cost of the battery cell. Therefore, when 0.3mm ≤ H3 ≤ 2.5mm, it can both reduce the risk of weld penetration during welding and improve the battery's energy density.

[0040] As an optional technical solution of the embodiment of the present application, the shell and the end cover are both made of steel.

[0041] In the above technical solution, steel has high strength and low cost. By making both the housing and end caps steel, the structural strength of the housing and end caps can be improved, reducing the risk of deformation due to stress, which is beneficial for improving the reliability of the battery cells. In addition, using the same material for the housing and end caps makes welding the housing and end caps easier, which helps to reduce the occurrence of welding cracks between the housing and end caps, thereby reducing the risk of leakage in the battery cells and improving the reliability of the battery cells.

[0042] In a second aspect, an embodiment of the present application further provides a battery, which includes the above-mentioned battery cell.

[0043] In a third aspect, an embodiment of the present application further provides an electric device, which includes the above-mentioned battery cell, and the battery cell is used to provide electric energy for the electric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] 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.

[0045] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0046] Figure 2 An exploded view of a battery provided in accordance with some embodiments of the present application;

[0047] Figure 3 A schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0048] Figure 4 An exploded view of a battery cell provided in some embodiments of the present application;

[0049] Figure 5 A schematic top view of an end cap provided in some embodiments of the present application;

[0050] Figure 6 for Figure 5 Cross-sectional view at position AA (showing the pressure relief mechanism);

[0051] Figure 7 for Figure 5 Cross-sectional view at the center AA position (with the pressure relief mechanism hidden);

[0052] Figure 8 Cross-sectional views of end caps provided in some other embodiments of the present application.

[0053] Icons: 10-casing; 11-first part; 12-second part; 20-battery cell; 21-shell; 22-end cover; 221-main body; 222-support part; 223-pressure relief hole; 224-groove; 225-first surface; 23-electrode assembly; 231-main body; 232-ear; 24-pressure relief mechanism; 241-pressure relief groove; 242-weld stamp; 243-second surface; 25-electrode terminal; 26-protective part; 27-insulating part; 100-battery; 200-controller; 300-motor; 1000-vehicle. DETAILED DESCRIPTION

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] The term "plurality" used in this application refers to two or more (including two).

[0061] 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.

[0062] The battery cells can be 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., which are not limited in the embodiments of the present application.

[0063] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits to a certain extent while allowing the active ions to pass through.

[0064] 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.

[0065] 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.

[0066] 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.).

[0067] 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 NCM622 ), 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 0.05 O2) and at least one of its modified compounds, etc.

[0068] In some embodiments, a positive electrode may utilize a metal foam. The metal foam may include nickel foam, copper foam, aluminum foam, alloy foam, or the like. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not include a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled or / and deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0069] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0070] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. may be used. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0076] In some embodiments, the separator is a separator membrane. There are many types of separator membranes, and any known separator membrane with a porous structure having good chemical stability and mechanical stability can be selected.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0083] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0084] 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.

[0085] 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.

[0086] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0087] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0088] In some embodiments, the electrode assembly is a laminate structure.

[0089] 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.

[0090] As an example, multiple positive electrode sheets may be provided, and the negative electrode sheet is folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0091] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0092] As an example, multiple separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0093] 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.

[0094] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0095] 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.

[0096] 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.

[0097] In some embodiments, the housing can be a sealed structure or a non-sealed structure. For example, when the housing is a sealed structure, the housing can protect the electrode assembly and, to a certain extent, prevent leakage of the electrolyte. When the housing is a non-sealed structure, the housing can also protect the electrode assembly. A sealing bag can be included between the housing and the electrode assembly to encapsulate the electrode assembly and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum-plastic film.

[0098] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include but are not limited to square-shell, blade-shaped, and polygonal batteries, such as hexagonal batteries.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0104] Currently, market developments indicate that batteries are increasingly being used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As battery applications continue to expand, market demand is also growing.

[0105] The development of battery technology requires simultaneous consideration of multiple design factors, including performance parameters such as battery life, energy density, discharge capacity, and charge / discharge rate. Furthermore, battery reliability must be considered. However, current battery reliability is relatively poor.

[0106] To improve the reliability of typical battery cells, a pressure relief structure is typically installed on the housing of the battery cell. This structure releases the internal pressure of the battery cell, effectively improving the reliability of the battery cell. In related art, the housing of a battery cell is typically made of aluminum, which has a relatively weak structural strength. The housing is easily deformed by external forces, which can pull on the pressure relief structure, causing it to prematurely open, resulting in poor reliability of the battery cell.

[0107] In view of this, an embodiment of the present application provides a battery cell, which includes a housing, an end cap, an electrode assembly, and a pressure relief mechanism. The housing has a storage space with an open end, and the end cap is connected to the housing and closes the opening. The end cap is provided with a pressure relief hole. The electrode assembly is accommodated in the storage space. The pressure relief mechanism is provided on the end cap and closes the pressure relief hole. The pressure relief mechanism is configured to release pressure within the battery cell. The pressure relief mechanism is made of steel or nickel, the end cap is made of steel, and the pressure relief mechanism is welded to the end cap.

[0108] The pressure relief mechanism of the battery cell is provided on the end cover. During manufacturing, the pressure relief mechanism can be connected to the end cover first, and then the end cover can be connected to the shell, which is conducive to simplifying manufacturing and reducing manufacturing costs. In addition, the space outside the end cover is relatively large, which can facilitate the pressure relief of the pressure relief mechanism. By making the material of the pressure relief mechanism include steel or nickel, and the material of the end cover include steel, on the one hand, the structural strength of the end cover and the pressure relief mechanism can be effectively improved, and the risk of deformation of the end cover and the pressure relief mechanism due to force is reduced, which is conducive to reducing the risk of the pressure relief mechanism opening the valve to relieve pressure prematurely, and is conducive to improving the service life and reliability of the battery cell. On the other hand, the pressure relief mechanism made of steel or nickel is easier to weld with the end cover made of steel, which is conducive to reducing the phenomenon of welding cracks between the pressure relief mechanism and the end cover, thereby reducing the risk of leakage of the battery cell and improving the reliability of the battery cell.

[0109] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0110] Electrically powered equipment may include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. 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, and may include but are not limited to electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0111] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle 1000 as an example.

[0112] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, to meet the power requirements for starting, navigating and driving the vehicle 1000.

[0113] 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.

[0114] Please refer to Figure 2 , Figure 2An exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and battery cells 20, with the battery cells 20 housed within the housing 10. The housing 10 is used to provide a storage space for the battery cells 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for the battery cells 20. The second portion 12 can be a hollow structure with one end open. The first portion 11 can be a plate-like structure, with the first portion 11 overlapping the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. The first portion 11 and the second portion 12 can also be hollow structures with one end open, with the open side of the first portion 11 overlapping the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0115] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0116] Each battery cell 20 may be a secondary battery cell or a primary battery cell; it may also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0117] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 , Figure 3 This is a schematic structural diagram of a battery cell 20 provided in some embodiments of the present application. Figure 4 An exploded view of a battery cell 20 provided in some embodiments of the present application. Figure 5 Schematic top view of the end cap 22 provided in some embodiments of the present application. Figure 6 for Figure 5 Cross-sectional view at position AA (showing the pressure relief mechanism 24). Figure 7 for Figure 5 Cross-sectional view at the AA position (the pressure relief mechanism 24 is hidden). An embodiment of the present application provides a battery cell 20, which includes a shell 21, an end cover 22, an electrode assembly 23 and a pressure relief mechanism 24. The shell 21 has a receiving space with an opening at one end, and the end cover 22 is connected to the shell 21 and closes the opening. The end cover 22 is provided with a pressure relief hole 223. The electrode assembly 23 is accommodated in the receiving space. The pressure relief mechanism 24 is arranged on the end cover 22 and closes the pressure relief hole 223. The pressure relief mechanism 24 is configured to be able to release the pressure inside the battery cell 20. Among them, the material of the pressure relief mechanism 24 includes steel or nickel, the material of the end cover 22 includes steel, and the pressure relief mechanism 24 is welded to the end cover 22.

[0118] The battery cell 20 refers to the smallest unit constituting the battery 100 .

[0119] The housing 21 has an accommodation space with one end open, and the accommodation space is used to accommodate the electrode assembly 23. The end cover 22 is connected to the housing 21 and closes the opening.

[0120] The end cap 22 is a component that fits over the opening of the housing 21 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. Optionally, the end cap 22 can be made of a material with a certain degree of hardness and strength (such as an aluminum alloy). This prevents the end cap 22 from deforming under pressure or collision, thereby enhancing the structural strength and reliability of the battery cell 20. Materials for the end cap 22 may include, but are not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, and plastic. The end cap 22 is also provided with an electrode terminal 25, which is used to electrically connect to the tab 232 of the electrode assembly 23 to input or output electrical energy from the battery cell 20. The electrode terminal 25 and the tab 232 can be directly connected, for example, by direct welding. Alternatively, the electrode terminal 25 and the tab 232 can be indirectly connected, for example, through a current collecting member. The battery cell 20 further includes an insulating member 27 disposed inside the end cap 22. The insulating member 27 can be used to isolate the electrical connection components in the housing 21 from the end cap 22 to reduce the risk of short circuits. For example, the insulating member 27 can be made of plastic, rubber, or the like.

[0121] The housing 21 is a component that cooperates with the end cap 22 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 23, electrolyte, and other components. The housing 21 and the end cap 22 can be independent components. An opening can be provided in the housing 21, and the end cap 22 is closed at the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 22 and the housing 21 can be integrated. Specifically, the end cap 22 and the housing 21 can form a common joint surface before other components are inserted into the housing. When the interior of the housing 21 needs to be encapsulated, the end cap 22 is closed to the housing 21. The housing 21 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined based on the specific shape and size of the electrode assembly 23. The material of the housing 21 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0122] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 23 may be contained in the housing 21. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets with active materials constitute the main body 231 of the electrode assembly 23, and the portions of the positive and negative electrode sheets without active materials each constitute a tab 232. The positive tab and the negative tab may be located together at one end of the main body 231 or respectively at both ends of the main body 231. During the charge and discharge process of the battery 100, the positive active material and the negative active material react with the electrolyte.

[0123] The end cap 22 is provided with a pressure relief hole 223, which penetrates the end cap 22 along the thickness direction of the end cap 22. In other words, the pressure relief hole 223 is a through hole provided in the end cap 22. Figure 4 and Figure 6 , the thickness direction of the end cover 22 may be the X direction shown in the figure.

[0124] The pressure relief mechanism 24 is a component designed to release the internal pressure of the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches the detonation pressure. The pressure relief mechanism 24 is mounted on the end cap 22. The pressure relief mechanism 24 is separately provided and connected to the end cap 22 (during manufacturing, a pressure relief hole 223 is provided in the end cap 22. The pressure relief mechanism 24 and the end cap 22 are provided separately and ultimately connected together). For example, the pressure relief mechanism 24 is a bursting disc mounted on the end cap 22.

[0125] The pressure relief mechanism 24 may be made of steel or nickel. The pressure relief mechanism 24 may be made of carbon steel or stainless steel. Carbon steel may be low carbon steel, medium carbon steel, or high carbon steel. For example, the pressure relief mechanism 24 may be made of 304 stainless steel, 305 stainless steel, 316 stainless steel, nickel, or the like.

[0126] The material of the end cap 22 can be carbon steel or stainless steel. Carbon steel can be low carbon steel, medium carbon steel or high carbon steel. For example, the material of the end cap 22 can be 304 stainless steel.

[0127] The pressure relief mechanism 24 of the battery cell 20 is mounted on the end cap 22. During manufacturing, the pressure relief mechanism 24 can be first connected to the end cap 22 and then to the housing 21, simplifying manufacturing and reducing manufacturing costs. Furthermore, the larger space outside the end cap 22 facilitates pressure relief by the pressure relief mechanism 24. By making the pressure relief mechanism 24 and the end cap 22 both steel- or nickel-based, the structural strength of the end cap 22 and the pressure relief mechanism 24 can be effectively enhanced, reducing the risk of deformation due to stress, and thus reducing the risk of premature opening of the pressure relief mechanism 24, thereby improving the service life and reliability of the battery cell 20. Furthermore, a pressure relief mechanism 24 made of steel or nickel is easier to weld to a steel end cap 22, reducing the risk of weld cracks between the pressure relief mechanism 24 and the end cap 22. This reduces the risk of leakage from the battery cell 20 and improves its reliability.

[0128] In some embodiments, the pressure relief mechanism 24 and the end cap 22 are both made of steel.

[0129] The steel material is carbon steel or stainless steel.

[0130] Illustratively, the carbon steel may be low carbon steel, medium carbon steel, or high carbon steel.

[0131] The pressure relief mechanism 24 and the end cap 22 can both be made of stainless steel, or carbon steel. In some embodiments, one of the pressure relief mechanism 24 and the end cap 22 is made of carbon steel, and the other of the pressure relief mechanism 24 and the end cap 22 is made of stainless steel.

[0132] When the pressure relief mechanism 24 and the end cap 22 are both made of carbon steel, the pressure relief mechanism 24 and the end cap 22 may both be made of low carbon steel, medium carbon steel, or high carbon steel. In some embodiments, one of the pressure relief mechanism 24 and the end cap 22 is made of medium carbon steel, and the other of the pressure relief mechanism 24 and the end cap 22 is made of low carbon steel or high carbon steel.

[0133] Steel is a material with high strength and low cost. By making both the pressure relief mechanism 24 and the end cap 22 from steel, the structural strength of the end cap 22 and the pressure relief mechanism 24 can be improved, reducing the risk of deformation of the end cap 22 and the pressure relief mechanism 24 due to stress. This helps reduce the risk of the pressure relief mechanism 24 prematurely opening the valve to release pressure, thereby improving the service life and reliability of the battery cell 20. In addition, the pressure relief mechanism 24 and the end cap 22 are made of the same material, making welding the pressure relief mechanism 24 and the end cap 22 easier, helping to reduce the occurrence of welding cracks between the pressure relief mechanism 24 and the end cap 22, thereby reducing the risk of leakage in the battery cell 20 and improving the reliability of the battery cell 20.

[0134] Optionally, the pressure relief mechanism 24 and the end cover 22 are both made of 304 stainless steel.

[0135] 304 stainless steel is also called 18 / 8 stainless steel, which means it contains more than 18% chromium and more than 8% nickel.

[0136] 304 stainless steel offers advantages such as corrosion resistance, high temperature resistance, and excellent processability. The pressure relief mechanism 24 and end cap 22 manufactured from 304 stainless steel possess high strength, reducing the risk of deformation of the end cap 22 and pressure relief mechanism 24 due to stress. This helps reduce the risk of premature valve opening of the pressure relief mechanism 24, thereby improving the service life and reliability of the battery cell 20. Furthermore, the pressure relief mechanism 24 and end cap 22 manufactured from 304 stainless steel are not easily corroded, which helps to extend the service life of the battery cell 20.

[0137] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 In some embodiments, the pressure relief mechanism 24 is in sheet shape, and the thickness of the pressure relief mechanism 24 is H1, which satisfies: 0.05 mm ≤ H1 ≤ 0.5 mm.

[0138] The pressure relief mechanism 24 is a sheet-like structure. For example, the pressure relief mechanism 24 is an explosion-proof disk.

[0139] H1 represents the thickness of the pressure relief mechanism 24. It should be noted that the thickness of the pressure relief mechanism 24 refers to the thickness of the pressure relief mechanism 24 at non-weak locations. For example, in some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 241, and the pressure relief mechanism 24 is configured to rupture along at least a portion of the pressure relief groove 241 when the battery cell 20 releases pressure. In this case, the thickness of the pressure relief mechanism 24 refers to the thickness of the pressure relief mechanism 24 excluding the pressure relief groove 241. When measuring, multiple measurements can be taken and the average value can be used as H1.

[0140] The thickness of the pressure relief mechanism 24 can be: H1 = 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc.

[0141] When H1 ≥ 0.05 mm, the thickness of the pressure relief mechanism 24 is greater, providing greater structural strength. This reduces the risk of deformation of the pressure relief mechanism 24 due to stress, thereby improving the service life and reliability of the battery cell 20. When H1 ≤ 0.5 mm, the thickness of the pressure relief mechanism 24 is not excessively large, which helps control the manufacturing cost of the battery cell 20. Therefore, when 0.05 mm ≤ H1 ≤ 0.5 mm, the service life, reliability, and manufacturing cost of the battery cell 20 are balanced.

[0142] Optionally, 0.05mm≤H1≤0.3mm.

[0143] The thickness of the pressure relief mechanism 24 can be: H1 = 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.25 mm, 0.28 mm, 0.3 mm, etc.

[0144] When H1 ≥ 0.05mm, the thickness of the pressure relief mechanism 24 is greater, providing greater structural strength. This reduces the risk of deformation of the pressure relief mechanism 24 due to stress, thereby improving the service life and reliability of the battery cell 20. When H1 ≤ 0.3mm, the thickness of the pressure relief mechanism 24 is not excessively large, further helping to control the manufacturing cost of the battery cell 20. Therefore, when 0.05mm ≤ H1 ≤ 0.3mm, the service life, reliability, and manufacturing cost of the battery cell 20 are better balanced.

[0145] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 In some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 241 , and the pressure relief mechanism 24 is configured to rupture along at least a portion of the pressure relief groove 241 when the battery cell 20 releases pressure.

[0146] The pressure relief mechanism 24 has an inner surface and an outer surface disposed opposite each other in the thickness direction of the end cap 22. The pressure relief groove 241 may be provided on the inner surface of the pressure relief mechanism 24, or the outer surface of the pressure relief mechanism 24. For example, the pressure relief groove 241 is provided on the outer surface of the pressure relief mechanism 24, that is, the pressure relief groove 241 is recessed from the outer surface toward the inner surface.

[0147] The pressure relief groove 241 can be formed by various methods, such as stamping, cold heading, etc. Taking stamping as an example, the pressure relief groove 241 can be stamped on the pressure relief mechanism 24 along the thickness direction of the end cover 22 .

[0148] Stamping or cold heading the pressure relief groove 241 causes the groove wall of the pressure relief groove 241 to undergo cold work hardening (changing the grain arrangement, causing lattice distortion, reducing the metal's plasticity, and increasing the material's hardness). This enhances its ability to resist external impact and makes it less susceptible to damage from external impact. This helps reduce the risk of leakage from the pressure relief mechanism 24.

[0149] A weak portion is formed on the pressure relief mechanism 24 by providing a pressure relief groove 241 on the pressure relief mechanism 24 . When the battery cell 20 releases pressure, the pressure relief mechanism 24 is cracked along at least a portion of the weak portion. This is simple, convenient and low-cost.

[0150] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 In some embodiments, the residual thickness of the pressure relief groove 241 is D, which satisfies: 0.01 mm ≤ D ≤ 0.3 mm.

[0151] D represents the residual thickness of the pressure relief groove 241, that is, the remaining thickness of the pressure relief mechanism 24 at the location where the pressure relief groove 241 is provided. When the pressure relief groove 241 is provided on the outer surface of the pressure relief mechanism 24, the residual thickness of the pressure relief groove 241 is the distance from the bottom surface of the pressure relief groove 241 to the inner surface of the pressure relief mechanism 24. When the pressure relief groove 241 is provided on the inner surface of the pressure relief mechanism 24, the residual thickness of the pressure relief groove 241 is the distance from the bottom surface of the pressure relief groove 241 to the outer surface of the pressure relief mechanism 24.

[0152] The residual thickness of the pressure relief groove 241 may be: D=0.01 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc.

[0153] When D ≥ 0.01 mm, the residual thickness of the pressure relief groove 241 is relatively large, which helps reduce the risk of the pressure relief mechanism 24 prematurely opening and releasing pressure, thereby improving the service life and reliability of the battery cell 20. When D ≤ 0.3 mm, the residual thickness of the pressure relief groove 241 is not too large, allowing the pressure relief mechanism 24 to open and release pressure promptly in the event of thermal runaway of the battery cell 20, thereby improving the timeliness of the pressure relief mechanism 24's pressure relief. Therefore, when 0.01 mm ≤ D ≤ 0.3 mm, the service life, reliability, and timeliness of pressure relief of the battery cell 20 are both maintained.

[0154] Optionally, 0.015mm≤D≤0.15mm.

[0155] The residual thickness of the pressure relief groove 241 can be: D = 0.015mm, 0.02mm, 0.025mm, 0.03mm, 0.035mm, 0.04mm, 0.045mm, 0.05mm, 0.055mm, 0.06mm, 0.065mm, 0.07mm, 0.075mm, 0.08mm, 0.085mm, 0.09mm, 0.095mm, 0.1mm, 0.105mm, 0.11mm, 0.115mm, 0.12mm, 0.125mm, 0.13mm, 0.135mm, 0.14mm, 0.145mm, 0.15mm, etc.

[0156] When D ≥ 0.015mm, the residual thickness of the pressure relief groove 241 is greater, which is more conducive to reducing the risk of the pressure relief mechanism 24 opening the valve to release pressure prematurely, thereby improving the service life and reliability of the battery cell 20. When D ≤ 0.15mm, the residual thickness of the pressure relief groove 241 is not too large, allowing the pressure relief mechanism 24 to open and release pressure more promptly in the event of thermal runaway of the battery cell 20, which is conducive to improving the timeliness of the pressure relief mechanism 24's pressure relief. Therefore, when 0.015mm ≤ D ≤ 0.15mm, the service life, reliability, and timeliness of pressure relief of the battery cell 20 are better balanced.

[0157] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 In some embodiments, the thickness of the end cap 22 is H2, which satisfies: 0.2 mm ≤ H2 ≤ 3 mm.

[0158] H2 represents the thickness of the end cap 22, that is, the distance between the outer surface of the end cap 22 and the inner surface of the end cap 22 along the thickness direction of the end cap 22. During measurement, multiple measurements can be taken to obtain an average value as H2.

[0159] The thickness of the end cap 22 can be: H2 = 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, etc.

[0160] When H2 ≥ 0.2 mm, the thickness of the end cap 22 is greater, providing greater structural strength. This reduces the risk of deformation of the end cap 22 due to stress, helps reduce the risk of premature valve opening of the pressure relief mechanism 24, and improves the service life and reliability of the battery cell 20. When H2 ≤ 3 mm, the thickness of the end cap 22 is not excessive, which helps control the manufacturing cost of the battery cell 20. Therefore, when 0.2 mm ≤ H2 ≤ 3 mm, the service life, reliability, and manufacturing cost of the battery cell 20 are balanced.

[0161] Optionally, 0.3mm≤H2≤2.5mm.

[0162] The thickness of the end cap 22 can be: H2 = 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, etc.

[0163] When H2 ≥ 0.3mm, the thickness of the end cap 22 is greater, providing greater structural strength and reducing the risk of deformation of the end cap 22 due to stress. This helps reduce the risk of premature opening of the pressure relief mechanism 24, thereby improving the service life and reliability of the battery cell 20. When H2 ≤ 2.5mm, the thickness of the end cap 22 is not excessive, which helps control the manufacturing cost of the battery cell 20. Therefore, when 0.3mm ≤ H2 ≤ 2.5mm, the service life, reliability, and manufacturing cost of the battery cell 20 are better balanced.

[0164] In some embodiments, the pressure relief mechanism 24 is located at an end of the pressure relief hole 223 facing the housing 21 .

[0165] The pressure relief hole 223 has two opposite ends along the thickness direction of the end cover 22 , one end facing the housing 21 and the other end away from the housing 21 . The pressure relief mechanism 24 is disposed at the end of the pressure relief hole 223 facing the housing 21 .

[0166] Optionally, the battery cell 20 includes a protective member 26 , which is disposed at an end of the pressure relief hole 223 facing away from the housing 21 and covers the pressure relief hole 223 .

[0167] When the pressure relief mechanism 24 is arranged at the end of the pressure relief hole 223 facing the shell 21, the risk of the pressure relief mechanism 24 being affected by external force is smaller, which is beneficial to reducing the risk of the pressure relief mechanism 24 opening the valve to relieve pressure prematurely and is beneficial to improving the service life and reliability of the battery cell 20.

[0168] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 In some embodiments, the end cap 22 has a first surface 225 facing the housing 21. The first surface 225 is provided with a groove 224. The groove 224 is connected to the pressure relief hole 223. The pressure relief mechanism 24 is partially accommodated in the groove 224. The portion of the pressure relief mechanism 24 accommodated in the groove 224 is welded to the end cap 22.

[0169] The end cap 22 has a first surface 225 facing the housing 21 , which is also the inner surface of the end cap 22 . The first surface 225 is provided with a groove 224 , which is recessed from the first surface 225 toward a direction away from the interior of the housing 21 .

[0170] Optionally, the groove 224 is an annular groove, and the groove 224 is arranged around the pressure relief hole 223 and communicates with the pressure relief hole 223 .

[0171] A portion of the pressure relief mechanism 24 is accommodated in the groove 224, and the portion of the pressure relief mechanism 24 accommodated in the groove 224 is welded to the end cover 22. For example, the outer peripheral surface of the pressure relief mechanism 24 may be welded to the side surface of the groove 224 to form the weld mark 242, or the outer peripheral surface of the pressure relief mechanism 24 may be welded to the first surface 225 to form the weld mark 242.

[0172] By providing a groove 224 on the end cover 22, the pressure relief mechanism 24 is partially accommodated in the groove 224. On the one hand, the groove 224 can position the pressure relief mechanism 24, thereby facilitating welding the pressure relief mechanism 24 to the end cover 22. On the other hand, the bottom wall of the groove 224 can support the pressure relief mechanism 24, making it difficult to weld through when welding the pressure relief mechanism 24 and the end cover 22.

[0173] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 In some embodiments, the portion of the pressure relief mechanism 24 received in the groove 224 has a second surface 243 facing the housing 21. Along the thickness direction of the end cap 22, the distance between the first surface 225 and the second surface 243 is L, satisfying: L≤0.15mm.

[0174] L represents the distance between the first surface 225 and the second surface 243 along the thickness direction of the end cover 22. L represents the height difference between the portion of the pressure relief mechanism 24 receiving the groove 224 and the first surface 225.

[0175] The distance between the first surface 225 and the second surface 243 along the thickness direction of the end cover 22 can be: L = 0.15mm, 0.14mm, 0.13mm, 0.12mm, 0.11mm, 0.1mm, 0.09mm, 0.08mm, 0.07mm, 0.06mm, 0.05mm, 0.04mm, 0.03mm, 0.02mm, 0.01mm, 0, etc.

[0176] By ensuring that the height difference between the first surface 225 and the second surface 243 along the thickness direction of the end cover 22 is less than or equal to 0.15 mm, the welding quality of the pressure relief mechanism 24 and the end cover 22 is improved.

[0177] Please refer to Figure 8 , Figure 8 The cross-sectional view of the end cap 22 is provided for some other embodiments of the present application. In some other embodiments, the first surface 225 and the second surface 243 are flush.

[0178] The first surface 225 and the second surface 243 are flush with each other, ie, L=0.

[0179] When the first surface 225 and the second surface 243 are flush, the pressure relief mechanism 24 and the end cover 22 can be welded by butt welding. The heat generated by butt welding is relatively small, which helps to reduce the risk of cracking of the pressure relief mechanism 24.

[0180] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 7 and Figure 8 In some embodiments, the end cap 22 includes a body portion 221 and a support portion 222. A pressure relief hole 223 is provided in the support portion 222. The support portion 222 and the body portion 221 jointly define a groove 224 that communicates with the pressure relief hole 223. The pressure relief mechanism 24 is partially accommodated in the groove 224 and abuts against the support portion 222. The pressure relief mechanism 24 is welded to the body portion 221.

[0181] The body portion 221 is connected to the support portion 222. The support portion 222 can serve as the bottom wall of the groove 224, and the body portion 221 can serve as the side wall of the groove 224. The support portion 222 encloses a pressure relief hole 223, which is in communication with the groove 224.

[0182] The pressure relief mechanism 24 is partially accommodated in the groove 224 , the support portion 222 abuts against the portion of the pressure relief mechanism 24 accommodated in the groove 224 , and the portion of the pressure relief mechanism 24 accommodated in the groove 224 is welded to the main body 221 .

[0183] The support portion 222 and the main body 221 jointly define a groove 224, which accommodates the pressure relief mechanism 24. On the one hand, the groove 224 can position the pressure relief mechanism 24, thereby facilitating welding the pressure relief mechanism 24 to the main body 221. On the other hand, the support portion 222 can support the pressure relief mechanism 24, making it difficult to weld through when welding the pressure relief mechanism 24 to the main body 221.

[0184] In some embodiments, the support portion 222 and the body portion 221 are integrally formed.

[0185] Integrally formed means that the support portion 222 and the main body 221 are an integral structure when provided. For example, the support portion 222 can be formed on the main body 221 by stamping or cold heading.

[0186] By integrally forming the support portion 222 and the main body portion 221 , the end cover 22 has better structural strength, which is beneficial to improving the reliability of the battery cell 20 .

[0187] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 7 and Figure 8 In some embodiments, along the thickness direction of the end cover 22 , the thickness of the support portion 222 is H3, satisfying: 0.2 mm ≤ H3 ≤ 3 mm.

[0188] H3 represents the thickness of the support portion 222 along the thickness direction of the end cover 22. During measurement, multiple measurements may be taken to obtain an average value.

[0189] The thickness of the support portion 222 along the thickness direction of the end cover 22 can be: H3 = 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, etc.

[0190] When H3 ≥ 0.2 mm, the thickness of the support portion 222 is greater, reducing the risk of weld penetration when welding the pressure relief mechanism 24 and the main body 221. When H3 ≤ 3 mm, the thickness of the support portion 222 is not excessively large. On the one hand, this can reduce the internal space occupied by the battery cell 20 or battery 100, thereby increasing the energy density of the battery 100. On the other hand, it can reduce material consumption and lower the cost of the battery cell 20. Therefore, when 0.2 mm ≤ H3 ≤ 3 mm, the risk of weld penetration during welding can be reduced while also increasing the energy density of the battery 100.

[0191] Optionally, 0.3mm≤H3≤2.5mm.

[0192] The thickness of the support portion 222 along the thickness direction of the end cover 22 can be: H3 = 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, etc.

[0193] When H3 ≥ 0.3 mm, the thickness of the support portion 222 is greater, further reducing the risk of weld penetration when welding the pressure relief mechanism 24 and the main body 221. When H3 ≤ 2.5 mm, the thickness of the support portion 222 is not excessively large. On the one hand, this can reduce the internal space occupied by the battery cell 20 or battery 100, thereby increasing the energy density of the battery 100. On the other hand, it can reduce material consumption and lower the cost of the battery cell 20. Therefore, when 0.3 mm ≤ H3 ≤ 2.5 mm, the risk of weld penetration during welding can be reduced while also increasing the energy density of the battery 100.

[0194] In some embodiments, the housing 21 and the end cover 22 are both made of steel.

[0195] The housing 21 and the end cap 22 may both be made of stainless steel, or both be made of carbon steel. In some embodiments, one of the housing 21 and the end cap 22 is made of carbon steel, and the other of the housing 21 and the end cap 22 is made of stainless steel.

[0196] When the shell 21 and the end cover 22 are both made of carbon steel, the shell 21 and the end cover 22 may both be made of low carbon steel, the shell 21 and the end cover 22 may both be made of medium carbon steel, or the shell 21 and the end cover 22 may both be made of high carbon steel. In some embodiments, one of the shell 21 and the end cover 22 is made of medium carbon steel, and the other of the shell 21 and the end cover 22 is made of low carbon steel or high carbon steel.

[0197] Steel is a material with high strength and low cost. By making both the housing 21 and the end cap 22 steel, the structural strength of the housing 21 and the end cap 22 can be improved, reducing the risk of deformation of the housing 21 and the end cap 22 under stress, which helps improve the reliability of the battery cell 20. Furthermore, using the same material for the housing 21 and the end cap 22 makes welding easier, which helps reduce the occurrence of weld cracks between the housing 21 and the end cap 22, thereby reducing the risk of leakage in the battery cell 20 and improving the reliability of the battery cell 20.

[0198] The embodiment of the present application further provides a battery 100 , which includes the above-mentioned battery cell 20 .

[0199] An embodiment of the present application further provides an electrical device, which includes the above-mentioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0200] According to some embodiments of this application, please refer to Figures 3 to 8 .

[0201] An embodiment of the present application provides a battery cell 20, which includes a housing 21, an end cap 22, an electrode assembly 23, and a pressure relief mechanism 24. The housing 21 has a storage space with an open end, and the end cap 22 is connected to the housing 21 and closes the opening. The end cap 22 is provided with a pressure relief hole 223. The electrode assembly 23 is accommodated in the storage space. The pressure relief mechanism 24 is disposed on the end cap 22 and closes the pressure relief hole 223. The pressure relief mechanism 24 is configured to release pressure from within the battery cell 20. The pressure relief mechanism 24 is made of steel or nickel, and the end cap 22 is made of steel. The pressure relief mechanism 24 is welded to the end cap 22. The pressure relief mechanism 24 of the battery cell 20 is disposed on the end cap 22. During manufacturing, the pressure relief mechanism 24 can be connected to the end cap 22 first, and then to the housing 21, which simplifies manufacturing and reduces manufacturing costs. In addition, the space outside the end cap 22 is relatively large, which facilitates pressure relief by the pressure relief mechanism 24. By making the pressure relief mechanism 24 comprise steel or nickel, and the end cap 22 comprise steel, the structural strength of the end cap 22 and the pressure relief mechanism 24 can be effectively improved, reducing the risk of deformation of the end cap 22 and the pressure relief mechanism 24 due to stress. This helps reduce the risk of the pressure relief mechanism 24 prematurely opening and releasing pressure, thereby improving the service life and reliability of the battery cell 20. Furthermore, the steel or nickel pressure relief mechanism 24 is easier to weld to the steel end cap 22, which helps reduce the risk of weld cracks between the pressure relief mechanism 24 and the end cap 22, thereby reducing the risk of leakage in the battery cell 20 and improving the reliability of the battery cell 20.

[0202] The pressure relief mechanism 24 and the end cover 22 are both made of steel. Steel has high strength and low cost. By making the pressure relief mechanism 24 and the end cover 22 both made of steel, the structural strength of the end cover 22 and the pressure relief mechanism 24 can be improved, and the risk of deformation of the end cover 22 and the pressure relief mechanism 24 due to stress can be reduced, which is conducive to reducing the risk of the pressure relief mechanism 24 opening the valve to relieve pressure prematurely, and is conducive to improving the service life and reliability of the battery cell 20. In addition, the pressure relief mechanism 24 and the end cover 22 are made of the same material, which makes it easier to weld the pressure relief mechanism 24 and the end cover 22, which is conducive to reducing the phenomenon of welding cracks between the pressure relief mechanism 24 and the end cover 22, thereby reducing the risk of leakage of the battery cell 20 and improving the reliability of the battery cell 20.

[0203] The pressure relief mechanism 24 and end cap 22 are both made of 304 stainless steel. 304 stainless steel offers advantages such as corrosion resistance, high temperature resistance, and excellent processability. The pressure relief mechanism 24 and end cap 22 made of 304 stainless steel possess high strength, reducing the risk of deformation due to stress on the end cap 22 and pressure relief mechanism 24. This helps reduce the risk of premature valve opening and pressure relief by the pressure relief mechanism 24, thereby improving the service life and reliability of the battery cell 20. Furthermore, the pressure relief mechanism 24 and end cap 22 made of 304 stainless steel are not easily corroded, which helps to extend the service life of the battery cell 20.

[0204] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: include: The shell has a receiving space with one end open; an end cover connected to the housing and closing the opening, the end cover being provided with a pressure relief hole; an electrode assembly, accommodated in the accommodation space; a pressure relief mechanism, disposed on the end cover and closing the pressure relief hole, the pressure relief mechanism being configured to release pressure inside the battery cell; The pressure relief mechanism is made of steel or nickel, the end cover is made of steel, and the pressure relief mechanism is connected to the end cover by welding.

2. The battery cell according to claim 1, characterized in that: The pressure relief mechanism and the end cover are both made of steel.

3. The battery cell according to claim 2, characterized in that: The pressure relief mechanism and the end cover are both made of 304 stainless steel.

4. The battery cell according to claim 1, characterized in that: The pressure relief mechanism is in sheet form, and the thickness of the pressure relief mechanism is H1, which satisfies: 0.05mm≤H1≤0.5mm.

5. The battery cell according to claim 4, characterized in that: 0.05mm≤H1≤0.3mm.

6. The battery cell according to claim 1, characterized in that: The pressure relief mechanism is provided with a pressure relief groove, and the pressure relief mechanism is configured to rupture along at least a portion of the pressure relief groove when the battery cell is pressure-relieved.

7. The battery cell according to claim 6, characterized in that: The residual thickness of the pressure relief groove is D, which satisfies: 0.01mm≤D≤0.3mm.

8. The battery cell according to claim 7, characterized in that: 0.015mm≤D≤0.15mm.

9. The battery cell according to claim 1, characterized in that: The thickness of the end cover is H2, which satisfies: 0.2mm≤H2≤3mm.

10. The battery cell according to claim 9, characterized in that: 0.3mm≤H2≤2.5mm.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The pressure relief mechanism is located at one end of the pressure relief hole facing the shell.

12. The battery cell according to claim 11, characterized in that: The end cover has a first surface facing the housing, the first surface is provided with a groove, and the groove is communicated with the pressure relief hole; The pressure relief mechanism is partially accommodated in the groove, and the portion of the pressure relief mechanism accommodated in the groove is welded to the end cover.

13. The battery cell according to claim 12, characterized in that: The portion of the pressure relief mechanism accommodated in the groove has a second surface facing the housing. Along the thickness direction of the end cover, a distance L between the first surface and the second surface satisfies: L≤0.15 mm.

14. The battery cell according to claim 13, characterized in that: The first surface and the second surface are flush.

15. The battery cell according to any one of claims 1 to 10, characterized in that: The end cover includes a main body and a support portion, the pressure relief hole is provided on the support portion, and the support portion and the main body jointly define a groove communicating with the pressure relief hole; The pressure relief mechanism is partially accommodated in the groove and abuts against the support portion, and the pressure relief mechanism is welded to the main body.

16. The battery cell according to claim 15, characterized in that: The support portion and the main body portion are integrally formed.

17. The battery cell according to claim 15, characterized in that: Along the thickness direction of the end cover, the thickness of the support portion is H3, which satisfies: 0.2 mm ≤ H3 ≤ 3 mm.

18. The battery cell according to claim 17, characterized in that: 0.3mm≤H3≤2.5mm.

19. The battery cell according to any one of claims 1 to 10, characterized in that: The shell and the end cover are both made of steel.

20. A battery, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 19.

21. An electrical device, characterized in that: The battery cell comprises a battery cell according to any one of claims 1 to 19, wherein the battery cell is used to provide electrical energy to the electrical device.

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