Battery cell, battery, and electric device

Abstract

The present application relates to the field of batteries, and provides a battery cell, a battery, and an electric device. The battery cell comprises a casing, an end cover, and a pressure relief mechanism. The casing is provided with an opening, and the end cover closes the opening and is welded and connected to the casing to form a first weld portion. The pressure relief mechanism is arranged on the end cover, the pressure relief mechanism comprises a weakened portion, and the weakened portion is configured to at least partially rupture when the battery cell undergoes pressure relief. In a direction perpendicular to the thickness direction of the end cover, the minimum distance between the weakened portion and the first weld portion is A, and the following condition is satisfied: A≥2.5 mm. By configuring the minimum distance between the weakened portion and the first weld portion in the direction perpendicular to the thickness direction of the end cover to be greater than or equal to 2.5 mm, the impact of high heat generated when welding the casing and the end cover on the weakened portion can be reduced, thereby reducing the risk of premature rupture of the weakened portion, and prolonging the service life of the battery cell.

Description

Battery cells, batteries and electrical equipment Cross-reference to related applications

[0001] This application claims priority to Chinese patent application filed on July 11, 2024, entitled “Battery Cell, Battery and Electrical Device” (application number: 2024109308647), the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of batteries, and more specifically, to a battery cell, a battery, and an electrical device. Background Technology

[0003] Batteries are widely used in the new energy field, such as in electric vehicles and new energy vehicles, which have become a new trend in the automotive industry. The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Additionally, battery lifespan must be considered. However, current batteries have relatively short lifespans. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell, a battery, and an electrical device, which aims to improve the problem of short battery life in related technologies.

[0005] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a housing, an end cap, and a pressure relief mechanism, the housing having an opening; the end cap closing the opening and being welded to the housing to form a first weld mark; the pressure relief mechanism being disposed on the end cap, the pressure relief mechanism including a weak portion, the weak portion being configured to at least partially crack when the battery cell is depressurized; wherein, along a direction perpendicular to the thickness direction of the end cap, the minimum distance between the weak portion and the first weld mark is A, satisfying: A≥2.5mm.

[0006] In the above technical solution, the casing and end cap are welded to form a first weld mark. The pressure relief mechanism can crack along at least a portion of the weak part when the battery cell is depressurized, so as to release the internal pressure of the battery cell. By making the minimum distance between the weak part and the first weld mark in the direction perpendicular to the thickness direction of the end cap greater than or equal to 2.5mm, it is beneficial to reduce the impact of high heat on the weak part during welding of the casing and end cap, reduce the risk of premature cracking of the weak part, and improve the life of the battery cell.

[0007] As an optional technical solution in this application embodiment, along the thickness direction of the end cap, the end of the housing where the opening is provided has a first end face, and the end cap has a second end face facing the first end face. The first end face and the second end face are welded together to form the first weld mark portion, satisfying: A≥3mm.

[0008] In the above technical solution, when the first end face and the second end face are welded to form the first weld mark, by making the minimum distance between the weak part and the first weld mark in the direction perpendicular to the thickness direction of the end cover greater than or equal to 3mm, it is more conducive to reducing the impact of high heat on the weak part when welding the shell and the end cover, which can further reduce the risk of the weak part cracking prematurely and is more conducive to improving the life of the battery cell.

[0009] As an optional technical solution in this application embodiment, the outer peripheral surface of the end cap is welded to the inner peripheral surface of the housing to form the first weld mark, satisfying: A≥3.5mm.

[0010] In the above technical solution, when the outer peripheral surface of the end cap is welded to the inner peripheral surface of the shell to form the first weld mark, the high heat during welding is more likely to affect the weak part. Therefore, by making the minimum distance between the weak part and the first weld mark in the direction perpendicular to the thickness direction of the end cap greater than or equal to 3.5mm, it is more conducive to reducing the impact of high heat on the weak part during welding of the shell and end cap, which can further reduce the risk of premature cracking of the weak part and is more conducive to improving the life of the battery cell.

[0011] As an optional technical solution in this application embodiment, the battery cell includes an electrode assembly, which is housed in the housing. The electrode assembly includes a first electrode lead-out portion, which is welded to the end cap to form a second solder mark portion. Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the weak portion and the second solder mark portion is B, which satisfies: B≥3mm.

[0012] In the above technical solution, the first electrode lead is electrically connected to the end cover, enabling the output of electrical energy from the electrode assembly or the input of electrical energy to the electrode assembly through the end cover. The first electrode lead is welded to the end cover to form a second solder mark. By ensuring that the minimum distance between the weak part and the second solder mark in the direction perpendicular to the thickness of the end cover is greater than or equal to 3mm, it is beneficial to reduce the impact of high heat during the welding of the first electrode lead and the end cover on the weak part, reduce the risk of premature cracking of the weak part, and improve the lifespan of the battery cell.

[0013] As an optional technical solution in this application embodiment, the first electrode lead-out portion includes a first electrode tab and a first current collector, the first current collector being electrically connected to the first electrode tab and the end cap, and the first current collector being welded to the end cap to form the second solder mark portion.

[0014] In the above technical solution, by setting the first current collector, it is easy to realize the electrical connection between the first electrode tab and the end cover, and reduce the difficulty of connecting the electrode assembly and the end cover.

[0015] As an optional technical solution in this application embodiment, the first current collector and the end cap are connected by through welding to form the second weld mark.

[0016] In the above technical solution, through-welding is used to connect the first current collector to the end cap, which is simple, convenient, and produces high-quality welds. Furthermore, during through-welding, the welding direction is approximately perpendicular to the thickness direction of the end cap, which reduces the impact on weak points, lowers the risk of premature cracking in these areas, and helps improve the lifespan of the battery cells.

[0017] As an optional technical solution in this application embodiment, the battery cell includes an electrode assembly, which is housed within the housing. The electrode assembly includes a first electrode lead-out portion, which is welded to the end cap to form a second solder mark portion. The thickness of the end cap is T. Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the first solder mark portion and the second solder mark portion is C, satisfying: C≥1.5T.

[0018] In the above technical solution, when the end cap is thicker, welding the first electrode lead-out portion and the end cap requires more heat, which will have a greater impact on the structure around the second solder mark portion. By making the minimum distance between the first solder mark portion and the second solder mark portion in the direction perpendicular to the thickness direction of the end cap greater than or equal to 1.5 times the thickness of the end cap, a larger gap is achieved between the first solder mark portion and the second solder mark portion, which helps to reduce the risk of local deformation of the end cap, reduce stress concentration, and improve welding quality.

[0019] As an optional technical solution in this application embodiment, along the thickness direction of the end cap, the end of the housing where the opening is provided has a first end face, and the end cap has a second end face facing the first end face. The first end face and the second end face are welded together to form the first weld mark portion, satisfying: C≥2T.

[0020] In the above technical solution, when the first end face and the second end face are welded to form the first weld mark, by making the minimum distance between the first weld mark and the second weld mark in the direction perpendicular to the thickness of the end cover greater than or equal to twice the thickness of the end cover, the first weld mark and the second weld mark have a larger gap, which is more conducive to reducing the risk of local deformation of the end cover, reducing stress concentration, and improving welding quality.

[0021] As an optional technical solution in this application embodiment, the outer peripheral surface of the end cap is welded to the inner peripheral surface of the housing to form the first weld mark, satisfying: C≥3T.

[0022] In the above technical solution, when the outer peripheral surface of the end cap is welded to the inner peripheral surface of the shell to form the first weld mark, by making the minimum distance between the first weld mark and the second weld mark in the direction perpendicular to the thickness of the end cap greater than or equal to 3 times the thickness of the end cap, the first weld mark and the second weld mark have a larger gap, which is more conducive to reducing the risk of local deformation of the end cap, reducing stress concentration, and improving welding quality.

[0023] As an optional technical solution in this application embodiment, the battery cell includes an insulating component and an electrode terminal. The electrode terminal is disposed on the end cap, and the insulating component is disposed between the electrode terminal and the end cap to insulate and isolate the electrode terminal from the end cap. Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the first solder mark and the insulating component is E, which satisfies: E≥1.5mm.

[0024] In the above technical solution, by making the minimum distance between the first solder mark and the insulating part in the direction perpendicular to the thickness direction of the end cover greater than or equal to 1.5mm, the distance between the first solder mark and the insulating part is larger, which helps to reduce the risk of the insulating part being burned by high heat during welding, so that the insulating part has a better insulation effect, reduces the risk of short circuit between the electrode terminal and the end cover, and helps to improve the reliability of the battery cell.

[0025] As an optional technical solution in this application embodiment, along the thickness direction of the end cap, the end of the housing where the opening is provided has a first end face, and the end cap has a second end face facing the first end face. The first end face and the second end face are welded together to form the first weld mark portion, satisfying: E≥2mm.

[0026] In the above technical solution, when the first end face and the second end face are welded to form the first solder mark, by making the minimum distance between the first solder mark and the insulating part in the direction perpendicular to the thickness direction of the end cover greater than or equal to 2mm, the distance between the first solder mark and the insulating part is larger, which is more conducive to reducing the risk of high heat burning the insulating part during welding, making the insulating part have a better insulation effect, further reducing the risk of short circuit between the electrode terminal and the end cover, and helping to improve the reliability of the battery cell.

[0027] As an optional technical solution in this application embodiment, the outer peripheral surface of the end cap is welded to the inner peripheral surface of the housing to form the first weld mark, satisfying: E≥2.5mm.

[0028] In the above technical solution, when the outer peripheral surface of the end cap is welded to the inner peripheral surface of the shell to form the first weld mark, the high heat during welding is more likely to affect the insulating component. Therefore, by making the minimum distance between the first weld mark and the insulating component in the direction perpendicular to the thickness direction of the end cap greater than or equal to 2.5mm, the distance between the first weld mark and the insulating component is larger, which is more conducive to reducing the risk of the insulating component being burned by the high heat during welding, so that the insulating component has a better insulation effect, further reducing the risk of short circuit between the electrode terminal and the end cap, and is conducive to improving the reliability of the battery cell.

[0029] As an optional technical solution in this application embodiment, the battery cell includes an insulating component and an electrode terminal. The electrode terminal is disposed on the end cap, and the insulating component is disposed between the electrode terminal and the end cap to insulate and isolate the electrode terminal from the end cap. Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the weak part and the insulating component is D, which satisfies: D≥4mm.

[0030] In the above technical solution, by making the minimum distance between the weak part and the insulating part in the direction perpendicular to the thickness of the end cap greater than or equal to 4mm, the distance between the weak part and the insulating part is larger, which can reduce the inhibitory effect of the insulating part on the deformation of the weak part, thereby facilitating the timely cracking of the weak part when the battery cell is depressurized, and improving the timeliness of the battery cell depressurization.

[0031] As an optional technical solution in this application embodiment, the battery cell includes an electrode assembly, an insulating member, and electrode terminals. The electrode assembly is housed within the housing. The electrode assembly includes a first electrode lead-out portion and a second electrode lead-out portion. The first electrode lead-out portion and the second electrode lead-out portion have opposite polarities. The first electrode lead-out portion is electrically connected to the end cover. The electrode terminals are disposed on the end cover and are electrically connected to the second electrode lead-out portion. The insulating member is disposed between the electrode terminals and the end cover to insulate and isolate the electrode terminals from the end cover.

[0032] In the above technical solution, the first electrode lead is electrically connected to the end cap, and the second electrode lead is electrically connected to the electrode terminal. This allows for the output or input of electrical energy to the electrode assembly via the end cap and electrode terminals. On one hand, this reduces the number of electrode terminals required, lowering costs, reducing the space occupied inside the battery, and increasing energy density. On the other hand, once the information acquisition device is electrically connected to the end cap, it can collect usage information from individual battery cells. This facilitates the connection of the information acquisition device to individual battery cells and data collection, reducing the difficulty of data collection from individual battery cells.

[0033] As an optional technical solution in this application embodiment, the first electrode lead-out portion is welded to the end cap to form a second solder mark portion. Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the second solder mark portion and the insulating component is F, which satisfies: F≥2mm.

[0034] In the above technical solution, by making the minimum distance between the second solder mark and the insulating part in the direction perpendicular to the thickness direction of the end cover greater than or equal to 2mm, the distance between the second solder mark and the insulating part is larger, which helps to reduce the risk of high heat burning the insulating part during welding, so that the insulating part has a better insulation effect, reduces the risk of short circuit between the electrode terminal and the end cover, and helps to improve the reliability of the battery cell.

[0035] As an optional technical solution in this application embodiment, the first electrode lead-out portion is welded to the end cap to form a second solder mark portion, and the second solder mark portion is an annular structure surrounding the electrode terminal.

[0036] In the above technical solution, the second solder mark is a ring structure, and the second solder mark is arranged around the outside of the electrode terminal. In this way, the first electrode lead-out part can be connected to the end cap more stably and has a large flow area.

[0037] As an optional technical solution in this application embodiment, the first solder mark is a ring structure.

[0038] In the above technical solution, when the first solder mark is an annular structure, the end cap is welded to the shell around its circumference, resulting in a high connection strength between the end cap and the shell. Furthermore, the first solder mark can seal the end cap and the shell, reducing the risk of external impurities entering the shell and reducing the risk of electrolyte leakage from the shell.

[0039] As an optional technical solution in this application embodiment, the weak part is a ring structure.

[0040] In the above technical solution, by setting the weak part as a ring structure, when the battery cell is depressurized, the depressurization mechanism can crack along the weak part, thereby opening a larger opening to facilitate rapid depressurization of the battery cell.

[0041] As an optional technical solution in this application embodiment, the pressure relief mechanism is provided with a pressure relief groove, and the pressure relief mechanism forms the weak part in the area where the pressure relief groove is provided.

[0042] In the above technical solution, the weak part is formed by opening a pressure relief groove on the pressure relief mechanism, which is simple, convenient and low in cost.

[0043] As an optional technical solution in this application embodiment, the pressure relief groove is disposed on the surface of the pressure relief mechanism away from the interior of the housing.

[0044] In the above technical solution, by setting the pressure relief groove on the surface of the pressure relief mechanism away from the inside of the housing, the tension that the weak part needs to overcome when it cracks is smaller, making it easier to crack.

[0045] As an optional technical solution in this application embodiment, the pressure relief mechanism is integrally formed with the end cap.

[0046] In the above technical solution, the pressure relief mechanism and the end cap are integrally molded, eliminating the need for additional welding or bonding processes, which helps reduce the risk of leakage from the pressure relief mechanism. Furthermore, during production, it is easier to ensure that the initial explosion pressure of multiple battery cells produced is relatively consistent.

[0047] As an optional technical solution in this application embodiment, the pressure relief mechanism is separately disposed from the end cover, the end cover is provided with a pressure relief hole, and the pressure relief mechanism is installed on the end cover and covers the pressure relief hole.

[0048] In the above technical solution, the pressure relief mechanism is separately set and installed on the end cover to facilitate processing and manufacturing.

[0049] As an optional technical solution in this application embodiment, the battery cell is a cylindrical battery cell, and the direction perpendicular to the thickness direction of the end cap is the radial direction of the end cap.

[0050] Secondly, embodiments of this application also provide a battery, the battery comprising the aforementioned battery cell.

[0051] Thirdly, embodiments of this application also provide an electrical device, the electrical device including the aforementioned battery cell, the battery cell being used to provide electrical energy to the electrical device. Attached Figure Description

[0052] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0054] Figure 2 is an exploded view of a battery provided in some embodiments of this application;

[0055] Figure 3 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0056] Figure 4 is an exploded view of a single battery cell provided in some embodiments of this application;

[0057] Figure 5 is a top view of a single battery cell provided in some embodiments of this application;

[0058] Figure 6 is a cross-sectional view of position AA in Figure 5;

[0059] Figure 7 is an enlarged view of position B in Figure 6;

[0060] Figure 8 is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application;

[0061] Figure 9 is a top view of a battery cell provided in some other embodiments of this application;

[0062] Figure 10 is a cross-sectional view at position CC in Figure 9;

[0063] Figure 11 is an enlarged view of position D in Figure 10.

[0064] Icons: 10-Box; 11-First part; 12-Second part; 20-Battery cell; 21-Housing shell; 211-Opening; 212-First end face; 22-End cap; 23-Pressure relief mechanism; 231-Weak part; 232-Pressure relief groove; 24-Electrode terminal; 25-Electrode assembly; 251-First electrode lead-out; 2511-First tab; 2512-First current collector; 252-Second electrode lead-out; 2521-Second tab; 2522-Second current collector; 26-Lower plastic; 27-First solder mark; 28-Second solder mark; 29-Insulator; 100-Battery; 200-Controller; 300-Motor; 1000-Vehicle. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0066] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0067] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0068] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0069] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0070] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0071] In this application, "multiple" means two or more (including two).

[0072] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0073] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0074] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, helps prevent short circuits to some extent while allowing active ions to pass through.

[0075] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0076] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0077] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be 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. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can 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.).

[0078] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional 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. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide 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, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0079] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0080] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0081] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors 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.).

[0082] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0083] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0084] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. 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, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0085] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0086] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0087] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0088] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0089] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0090] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0091] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0092] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0093] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0094] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0095] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0096] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0097] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0098] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0099] In some implementations, the electrode assembly is a stacked structure.

[0100] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0101] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0102] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0103] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0104] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0105] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0106] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0107] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0108] In some embodiments, the housing can be a sealed structure or a non-sealed structure. As an example, when the housing is a sealed structure, it can protect the electrode assembly and prevent, to some extent, electrolyte leakage. When the housing is a non-sealed structure, it can still protect the electrode assembly, and a sealing bag may be included between the housing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film.

[0109] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include, but are not limited to, square battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0110] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0111] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0112] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0113] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0114] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0115] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0116] To improve the reliability of individual battery cells, existing technologies involve creating a weak point on the end cap. When the internal pressure of the battery cell reaches the explosion pressure, the weak point cracks to release the internal pressure and reduce the risk of the battery cell exploding or catching fire.

[0117] However, the weak points in the existing technology often open prematurely, resulting in a shorter lifespan for individual battery cells.

[0118] Research has found that in existing technologies, the high heat generated during welding of the casing and end caps can affect weak points, causing them to be damaged. Even if the weak points are not damaged, the material grains in the weak points can easily change, making them softer and more prone to premature opening, resulting in a shorter lifespan for the battery cells.

[0119] In view of this, this application provides a battery cell including a housing, an end cap, and a pressure relief mechanism. The housing has an opening, and the end cap closes the opening and is welded to the housing to form a first weld mark. The pressure relief mechanism is disposed on the end cap and includes a weak portion. The pressure relief mechanism is configured to crack along at least a portion of the weak portion when the battery cell is depressurized. The minimum distance A between the weak portion and the first weld mark in a direction perpendicular to the thickness direction of the end cap satisfies: A ≥ 2.5 mm.

[0120] The casing and end cap are welded to form a first weld mark. The pressure relief mechanism can crack along at least a portion of the weak part when the battery cell is depressurized, so as to release the internal pressure of the battery cell. By making the minimum distance between the weak part and the first weld mark in the direction perpendicular to the thickness direction of the end cap greater than or equal to 2.5 mm, it is beneficial to reduce the impact of high heat on the weak part during the welding of the casing and end cap, reduce the risk of premature cracking of the weak part, and improve the life of the battery cell.

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

[0122] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, which may include, but are not limited to, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0123] For ease of explanation, the following embodiments will use a vehicle 1000 as an example of electrical equipment.

[0124] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also 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 needs of the vehicle 1000 during startup, navigation, and driving.

[0125] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0126] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of this application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the space. Alternatively, the first portion 11 and the second portion 12 may both be hollow structures with one open side, with the open side of the first portion 11 covering 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 cuboid, etc.

[0127] In battery 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, battery 100 can also be composed of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 10. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0128] Each battery cell 20 can be a secondary battery cell or a primary battery cell; it can also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0129] Please refer to Figures 3, 4, 5, 6, and 7. Figure 3 is a structural schematic diagram of a battery cell 20 provided in some embodiments of this application. Figure 4 is an exploded view of a battery cell 20 provided in some embodiments of this application. Figure 5 is a top view of a battery cell 20 provided in some embodiments of this application. Figure 6 is a cross-sectional view at position AA in Figure 5. Figure 7 is an enlarged view at position B in Figure 6. This application provides a battery cell 20, which includes a housing 21, an end cap 22, and a pressure relief mechanism 23. The housing 21 has an opening 211, and the end cap 22 closes the opening 211 and is welded to the housing 21 to form a first solder mark 27. The pressure relief mechanism 23 is disposed on the end cap 22 and includes a weak portion 231. The pressure relief mechanism 23 is configured to crack along at least a portion of the weak portion 231 when the battery cell 20 is depressurized. The minimum distance A between the weak portion 231 and the first solder mark 27 in a direction perpendicular to the thickness direction of the end cap 22 satisfies: A ≥ 2.5 mm.

[0130] Battery cell 20 refers to the smallest unit that makes up battery 100.

[0131] The housing 21 has a receiving space with an opening 211 at one end for accommodating the electrode assembly 25. The end cap 22 is connected to the housing 21 and closes the opening 211.

[0132] End cap 22 refers to a component that covers the opening 211 of housing 21 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 22 can be adapted to the shape of housing 21 to fit it. Optionally, end cap 22 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 22 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved reliability. The material of end cap 22 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. Battery cell 20 also includes lower plastic 26, which is disposed inside end cap 22. Lower plastic 26 can be used to isolate electrical connection components inside housing 21 from end cap 22 to reduce the risk of short circuit. For example, lower plastic 26 can be plastic, rubber, etc.

[0133] The housing 21 is a component used to cooperate with the end cap 22 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 25, electrolyte, and other components. The housing 21 and the end cap 22 can be independent components. An opening 211 can be provided on the housing 21, and the end cap 22 can be used to close the opening 211 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 mating surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 21, the end cap 22 closes the housing 21. The housing 21 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 25. The material of the housing 21 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0134] Electrode assembly 25 is the component in the battery cell 20 where electrochemical reactions occur. The casing 21 may contain one or more electrode assemblies 25. The electrode assembly 25 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly 25, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery 100, the positive and negative active materials react with the electrolyte.

[0135] The first weld mark 27 is the weld mark left after welding the housing 21 and the end cap 22. The welding method is not limited, such as gas welding, electric welding, laser welding, etc.

[0136] The pressure relief mechanism 23 is a component used to open when the internal pressure or temperature of the battery cell 20 reaches the explosion pressure, thereby releasing the internal pressure of the battery cell 20. The pressure relief mechanism 23 is disposed on the end cover 22. The pressure relief mechanism 23 can be a component mounted on the end cover 22, in which case the pressure relief mechanism 23 and the end cover 22 are separately disposed but connected. For example, the pressure relief mechanism 23 is an explosion-proof plate mounted on the end cover 22. The pressure relief mechanism 23 can also be part of the end cover 22, in which case the pressure relief mechanism 23 and the end cover 22 are integrally formed.

[0137] The weak portion 231 serves a pressure relief function, allowing the pressure relief mechanism 23 to crack along the weak portion 231 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, thereby releasing the internal pressure of the battery cell 20. In some embodiments, the strength of the pressure relief mechanism 23 at the weak portion 231 may be lower than the strength at other locations of the pressure relief mechanism 23, so that the weak portion 231 can crack under the internal pressure when the internal pressure or temperature of the battery cell 20 reaches the predetermined value, thereby releasing the internal pressure of the battery cell 20. In other embodiments, the melting point of the pressure relief mechanism 23 at the weak portion 231 may be lower than the melting point at other locations of the pressure relief mechanism 23. Thus, when the internal pressure or temperature of the battery cell 20 reaches the predetermined value, the weak portion 231 can crack under the high temperature, thereby releasing the internal pressure of the battery cell 20.

[0138] A represents the minimum distance between the weak part 231 and the first solder mark 27 in the direction perpendicular to the thickness direction of the end cap 22.

[0139] Referring to Figures 6 and 7, the thickness direction of the end cap 22 is the X direction as shown in the figures. The direction perpendicular to the thickness direction of the end cap 22 is the Y direction as shown in the figures. In the embodiment shown in Figures 6 and 7, the battery cell 20 is a cylindrical battery cell 20. The direction perpendicular to the thickness direction of the end cap 22 is the radial direction of the end cap 22.

[0140] The minimum distance between the weak part 231 and the first solder mark 27 along the direction perpendicular to the thickness direction of the end cap 22 can be: A = 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4mm, etc.

[0141] The housing 21 and the end cap 22 are welded to form a first weld mark 27. The pressure relief mechanism 23 can crack along at least a portion of the weak part 231 when the battery cell 20 is depressurized, so as to release the internal pressure of the battery cell 20. By making the minimum distance between the weak part 231 and the first weld mark 27 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 2.5 mm, it is beneficial to reduce the impact of high heat on the weak part 231 during the welding of the housing 21 and the end cap 22, reduce the risk of premature cracking of the weak part 231, and improve the life of the battery cell 20.

[0142] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, along the thickness direction of the end cap 22, the end of the housing 21 with the opening 211 has a first end face 212, and the end cap 22 has a second end face facing the first end face 212. The first end face 212 and the second end face are welded together to form a first weld mark 27, satisfying: A≥3mm.

[0143] The first end face 212 is the end face of the housing 21 surrounding the opening 211. The second end face is the end face of the end cap 22 facing the housing 21. The first end face 212 and the second end face are arranged opposite to each other along the thickness direction of the end cap 22. The first end face 212 and the second end face are welded to form a first solder mark 27.

[0144] When the first end face 212 and the second end face are welded together to form the first weld mark 27, the minimum distance between the weak part 231 and the first weld mark 27 along the direction perpendicular to the thickness direction of the end cover 22 can be: A = 3mm, 3.05mm, 3.1mm, 3.15mm, 3.2mm, 3.25mm, 3.3mm, 3.35mm, 3.4mm, 3.45mm, 3.5mm, 3.55mm, 3.6mm, 3.65mm, etc.

[0145] When the first end face 212 and the second end face are welded to form the first weld mark 27, by making the minimum distance between the weak part 231 and the first weld mark 27 in the direction perpendicular to the thickness direction of the end cover 22 greater than or equal to 3mm, it is more beneficial to reduce the impact of high heat on the weak part 231 when welding the shell 21 and the end cover 22, which can further reduce the risk of the weak part 231 cracking prematurely and is more beneficial to improving the life of the battery cell 20.

[0146] Please refer to Figures 8, 9, 10, and 11. Figure 8 is a structural schematic diagram of the battery cell 20 provided in some embodiments of this application. Figure 9 is a top view of the battery cell 20 provided in some embodiments of this application. Figure 10 is a cross-sectional view at position CC in Figure 9. Figure 11 is an enlarged view at position D in Figure 10. In some embodiments, the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form a first weld mark 27, satisfying: A ≥ 3.5 mm.

[0147] When the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form the first weld mark 27, the minimum distance between the weak part 231 and the first weld mark 27 along the direction perpendicular to the thickness direction of the end cap 22 can be: A = 3.5mm, 3.55mm, 3.6mm, 3.65mm, 3.7mm, 3.75mm, 3.8mm, 3.85mm, 3.9mm, 3.95mm, 4mm, etc.

[0148] When the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form the first weld mark 27, the high heat during welding is more likely to affect the weak part 231. Therefore, by making the minimum distance between the weak part 231 and the first weld mark 27 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 3.5 mm, it is more beneficial to reduce the impact of the high heat during welding of the housing 21 and the end cap 22 on the weak part 231, which can further reduce the risk of the weak part 231 cracking prematurely and is more beneficial to improving the life of the battery cell 20.

[0149] In some other embodiments, the inner peripheral surface of the end cap 22 is welded to the outer peripheral surface of the housing 21 to form a first weld mark 27.

[0150] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the battery cell 20 includes an electrode assembly 25, which is housed within a housing 21. The electrode assembly 25 includes a first electrode lead-out portion 251, which is welded to an end cap 22 to form a second solder mark portion 28. Along a direction perpendicular to the thickness direction of the end cap 22, the minimum distance B between the weak portion 231 and the second solder mark portion 28 satisfies: B ≥ 3 mm.

[0151] The first electrode lead-out portion 251 is a structure used to lead out electrical energy from the electrode assembly 25 or to introduce electrical energy into the electrode assembly 25. The first electrode lead-out portion 251 includes a first tab 2511, which is either a positive or negative tab as described above, and can be directly connected to the end cap 22. In some embodiments, the first electrode lead-out portion 251 may also include other electrical connection components connected to the first tab 2511. For example, the first electrode lead-out portion 251 may also include a first current collector 2512, which connects the first tab 2511 and the end cap 22 to guide the electrical energy of the electrode assembly 25 to the end cap 22 or receive electrical energy introduced from the end cap 22.

[0152] The first electrode tab 2511 can be either a positive or a negative electrode tab. When the first electrode tab 2511 is a positive electrode tab, the electrode terminal 24 is a negative electrode terminal 24. When the first electrode tab 2511 is a negative electrode tab, the electrode terminal 24 is a positive electrode terminal 24.

[0153] The second solder mark 28 is the solder mark left after welding the end cap 22 and the first electrode terminal 24. The welding method is not limited, such as gas welding, electric welding, laser welding, etc.

[0154] B represents the minimum distance between the weak part 231 and the second solder mark 28 in the direction perpendicular to the thickness direction of the end cap 22.

[0155] The minimum distance between the weak part 231 and the second solder mark 28 along the direction perpendicular to the thickness direction of the end cap 22 can be: B = 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, etc.

[0156] The first electrode lead-out portion 251 is electrically connected to the end cap 22, enabling the output of electrical energy from the electrode assembly 25 or the input of electrical energy to the electrode assembly 25 through the end cap 22. The first electrode lead-out portion 251 and the end cap 22 are welded to form a second solder mark portion 28. By ensuring that the minimum distance between the weak portion 231 and the second solder mark portion 28 in the direction perpendicular to the thickness direction of the end cap 22 is greater than or equal to 3mm, it is beneficial to reduce the impact of high heat during the welding of the first electrode lead-out portion 251 and the end cap 22 on the weak portion 231, reduce the risk of premature cracking of the weak portion 231, and improve the lifespan of the battery cell 20.

[0157] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the first electrode lead-out portion 251 includes a first tab 2511 and a first current collector 2512, the first current collector 2512 being electrically connected to the first tab 2511 and the end cap 22. The first current collector 2512 is welded to the end cap 22 to form a second solder mark portion 28.

[0158] When the first electrode lead-out portion 251 includes the first current collector 2512, the first current collector 2512 is electrically connected to the first electrode tab 2511 and the end cap 22, and the second solder mark portion 28 is the solder mark portion left after the first current collector 2512 and the end cap 22 are soldered.

[0159] By setting the first current collector 2512, it is easier to realize the electrical connection between the first electrode tab 2511 and the end cover 22, and the connection difficulty between the electrode assembly 25 and the end cover 22 is reduced.

[0160] In some embodiments, the first current collector 2512 and the end cap 22 are connected by through welding to form a second weld mark 28.

[0161] During penetration welding, the end cap 22 and the first current collector 2512 can be welded along the direction from the end cap 22 to the first current collector 2512.

[0162] The connection between the first current collector 2512 and the end cap 22 is achieved by through welding, which is simple, convenient, and produces high-quality welds. Furthermore, during through welding, the welding direction is approximately perpendicular to the thickness direction of the end cap 22, which reduces the impact on the weak part 231, lowers the risk of premature cracking of the weak part 231, and helps to improve the lifespan of the battery cell 20.

[0163] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the battery cell 20 includes an electrode assembly 25, which is housed within a housing 21. The electrode assembly 25 includes a first electrode lead-out portion 251, which is welded to an end cap 22 to form a second solder mark portion 28. The end cap 22 has a thickness of T. Along a direction perpendicular to the thickness of the end cap 22, the minimum distance between the first solder mark portion 27 and the second solder mark portion 28 is C, satisfying: C ≥ 1.5T.

[0164] T represents the thickness of end cap 22. The thickness of end cap 22 can be measured at multiple locations and the average value can be taken as the thickness of end cap 22.

[0165] C represents the minimum distance between the first solder mark 27 along the direction perpendicular to the thickness of the end cap 22 and the second solder mark 28.

[0166] The minimum distance between the first solder mark 27 and the second solder mark 28 in the direction perpendicular to the thickness direction of the end cap 22 can be: C = 1.5T, 1.6T, 1.7T, 1.8T, 1.9T, 2T, 2.1T, 2.2T, 2.3T, 2.4T, 2.5T, 2.6T, 2.7T, 2.8T, 2.9T, 3T, 3.1T, 3.2T, 3.3T, 3.4T, 3.5T, etc.

[0167] When the end cap 22 is thicker, welding the first electrode lead-out portion 251 and the end cap 22 requires more heat, which will have a greater impact on the structure around the second solder mark portion 28. By making the minimum distance between the first solder mark portion 27 and the second solder mark portion 28 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 1.5 times the thickness of the end cap 22, a larger spacing is achieved between the first solder mark portion 27 and the second solder mark portion 28, which helps to reduce the risk of local deformation of the end cap 22, reduce stress concentration, and improve welding quality.

[0168] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, along the thickness direction of the end cap 22, the end of the housing 21 with the opening 211 has a first end face 212, and the end cap 22 has a second end face facing the first end face 212. The first end face 212 and the second end face are welded together to form a first weld mark 27, satisfying: C≥2T.

[0169] The first end face 212 is the end face of the housing 21 surrounding the opening 211. The second end face is the end face of the end cap 22 facing the housing 21. The first end face 212 and the second end face are arranged opposite each other along the thickness direction of the end cap 22. The first end face 212 and the second end face are welded to form a first solder mark 27. When the first end face 212 and the second end face are welded together to form the first solder mark 27, the minimum distance between the first solder mark 27 and the second solder mark 28 along the direction perpendicular to the thickness direction of the end cap 22 can be: C = 2T, 2.05T, 2.1T, 2.15T, 2.2T, 2.25T, 2.3T, 2.35T, 2.4T, 2.45T, 2.5T, 2.55T, 2.6T, 2.65T, 2.7T, 2.75T, 2.8T, 2.85T, 2.9T, 2.95T, 3T, etc.

[0170] When the first end face 212 and the second end face are welded to form the first weld mark 27, by making the minimum distance between the first weld mark 27 and the second weld mark 28 in the direction perpendicular to the thickness direction of the end cover 22 greater than or equal to twice the thickness of the end cover 22, the first weld mark 27 and the second weld mark 28 have a larger gap, which is more conducive to reducing the risk of local deformation of the end cover 22, reducing stress concentration, and improving welding quality.

[0171] Referring to Figures 8, 9, 10 and 11, in some embodiments, the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form a first weld mark 27, satisfying: C≥3T.

[0172] When the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form the first weld mark 27, the minimum distance between the first weld mark 27 and the second weld mark 28 in the direction perpendicular to the thickness direction of the end cap 22 can be: C = 3T, 3.05T, 3.1T, 3.15T, 3.2T, 3.25T, 3.3T, 3.35T, 3.4T, 3.45T, 3.5T, 3.55T, 3.6T, 3.65T, 3.7T, 3.75T, 3.8T, 3.85T, 3.9T, 3.95T, 4T, etc.

[0173] When the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form the first weld mark 27, the minimum distance between the first weld mark 27 and the second weld mark 28 in the direction perpendicular to the thickness of the end cap 22 is greater than or equal to three times the thickness of the end cap 22. This results in a larger gap between the first weld mark 27 and the second weld mark 28, which is more conducive to reducing the risk of local deformation of the end cap 22, reducing stress concentration, and improving welding quality.

[0174] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the battery cell 20 includes an insulating member 29 and an electrode terminal 24. The electrode terminal 24 is disposed on the end cap 22, and the insulating member 29 is disposed between the electrode terminal 24 and the end cap 22 to insulate and isolate the electrode terminal 24 from the end cap 22. Along a direction perpendicular to the thickness direction of the end cap 22, the minimum distance between the first solder mark 27 and the insulating member 29 is E, satisfying: E ​​≥ 1.5 mm.

[0175] The end cap 22 is also provided with electrode terminals 24, which are used to electrically connect to the tabs of the electrode assembly 25 to input or output electrical energy from the battery cell 20. Electrode terminals 24 and tabs can be directly connected, for example, by direct welding. Electrode terminals 24 and tabs can also be indirectly connected, for example, by indirect connection through a current collector.

[0176] The insulating element 29, commonly known as the plastic coating, is at least partially disposed between the electrode terminal 24 and the end cap 22, and the insulating element 29 can insulate and isolate the electrode terminal 24 and the end cap 22. For example, the insulating element 29 can be plastic, rubber, etc.

[0177] E represents the minimum distance between the first solder mark 27 and the insulating member 29 in the direction perpendicular to the thickness direction of the end cap 22.

[0178] The minimum distance between the first solder mark 27 and the insulating member 29 along the direction perpendicular to the thickness direction of the end cap 22 can be: E = 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, etc.

[0179] By making the minimum distance between the first solder mark 27 and the insulating component 29 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 1.5mm, the distance between the first solder mark 27 and the insulating component 29 is larger, which helps to reduce the risk of the insulating component 29 being burned by high heat during welding, so that the insulating component 29 has a better insulation effect, reduces the risk of short circuit between the electrode terminal 24 and the end cap 22, and helps to improve the reliability of the battery cell 20.

[0180] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, along the thickness direction of the end cap 22, the end of the housing 21 with the opening 211 has a first end face 212, and the end cap 22 has a second end face facing the first end face 212. The first end face 212 and the second end face are welded together to form a first weld mark 27, satisfying: E≥2mm.

[0181] The first end face 212 is the end face of the housing 21 surrounding the opening 211. The second end face is the end face of the end cap 22 facing the housing 21. The first end face 212 and the second end face are positioned opposite each other along the thickness direction of the end cap 22. The first end face 212 and the second end face are welded together to form a first solder mark 27. When the first end face 212 and the second end face are welded together to form the first solder mark 27, the minimum distance between the first solder mark 27 and the insulating member 29 along the direction perpendicular to the thickness direction of the end cap 22 can be: E = 2mm, 2.05mm, 2.1mm, 2.15mm, 2.2mm, 2.25mm, 2.3mm, 2.35mm, 2.4mm, 2.45mm, 2.5mm, 2.55mm, 2.6mm, 2.65mm, etc.

[0182] When the first end face 212 and the second end face are welded to form the first solder mark 27, the minimum distance between the first solder mark 27 and the insulating member 29 in the direction perpendicular to the thickness direction of the end cover 22 is greater than or equal to 2mm. This makes the distance between the first solder mark 27 and the insulating member 29 larger, which is more conducive to reducing the risk of the insulating member 29 being burned by high heat during welding. This makes the insulating member 29 have a better insulation effect, further reducing the risk of short circuit between the electrode terminal 24 and the end cover 22, and is conducive to improving the reliability of the battery cell 20.

[0183] Referring to Figures 8, 9, 10, and 11, in some embodiments, the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form a first weld mark 27, satisfying: E≥2.5mm.

[0184] When the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form the first weld mark 27, the minimum distance between the first weld mark 27 and the insulating member 29 in the direction perpendicular to the thickness direction of the end cap 22 can be: E = 2.5mm, 2.55mm, 2.6mm, 2.65mm, 2.7mm, 2.75mm, 2.8mm, 2.85mm, 2.9mm, 2.95mm, 3mm, etc.

[0185] When the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form the first solder mark 27, the high heat during welding is more likely to affect the insulating component 29. Therefore, by making the minimum distance between the first solder mark 27 and the insulating component 29 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 2.5 mm, the distance between the first solder mark 27 and the insulating component 29 is larger, which is more conducive to reducing the risk of the insulating component 29 being burned by the high heat during welding, so that the insulating component 29 has a better insulation effect, further reducing the risk of short circuit between the electrode terminal 24 and the end cap 22, which is conducive to improving the reliability of the battery cell 20.

[0186] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the battery cell 20 includes an insulator 29 and an electrode terminal 24. The electrode terminal 24 is disposed on the end cap 22, and the insulator 29 is disposed between the electrode terminal 24 and the end cap 22 to insulate and isolate the electrode terminal 24 from the end cap 22. Along a direction perpendicular to the thickness direction of the end cap 22, the minimum distance D between the weak portion 231 and the insulator 29 satisfies: D ≥ 4 mm.

[0187] D represents the minimum distance between the weak part 231 and the insulating part 29 along the direction perpendicular to the thickness direction of the end cap 22.

[0188] The minimum distance between the weak part 231 and the insulating part 29 along the direction perpendicular to the thickness direction of the end cap 22 can be: D = 4mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm, etc.

[0189] By making the minimum distance between the weak part 231 and the insulating member 29 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 4mm, the distance between the weak part 231 and the insulating member 29 is larger, which can reduce the inhibitory effect of the insulating member 29 on the deformation of the weak part 231, thereby facilitating the timely cracking of the weak part 231 when the battery cell 20 is depressurized, and improving the timeliness of depressurization of the battery cell 20.

[0190] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the battery cell 20 includes an electrode assembly 25, an insulator 29, and electrode terminals 24. The electrode assembly 25 is housed within a housing 21. The electrode assembly 25 includes a first electrode lead-out 251 and a second electrode lead-out 252, with opposite polarities. The first electrode lead-out 251 is electrically connected to an end cap 22, and the electrode terminals 24 are disposed on the end cap 22 and electrically connected to the second electrode lead-out 252. The insulator 29 is disposed between the electrode terminals 24 and the end cap 22 to insulate and isolate the electrode terminals 24 from the end cap 22.

[0191] The second electrode lead-out portion 252 is a structure used to lead out electrical energy from the electrode assembly 25 or to introduce electrical energy into the electrode assembly 25. The second electrode lead-out portion 252 includes a second tab 2521, which can be either a negative or positive tab as described above, and can be directly connected to the electrode terminal 24. In other embodiments, the second electrode lead-out portion 252 may also include other electrical connection components connected to the second tab 2521. For example, the second electrode lead-out portion 252 may also include a second current collector 2522, which connects the second tab 2521 and the electrode terminal 24 to guide electrical energy from the electrode assembly 25 to the electrode terminal 24 or receive electrical energy introduced from the electrode terminal 24.

[0192] The first electrode lead 251 and the second electrode lead 252 have opposite polarities. For example, when the first electrode lead 251 is a positive electrode lead, the second electrode lead 252 is a negative electrode lead. When the first electrode lead 251 is a negative electrode lead, the second electrode lead 252 is a positive electrode lead. Correspondingly, the first electrode tab 2511 and the second electrode tab 2521 have opposite polarities. For example, when the first electrode tab 2511 is a positive electrode tab, the second electrode tab 2521 is a negative electrode tab. When the first electrode tab 2511 is a negative electrode tab, the second electrode tab 2521 is a positive electrode tab.

[0193] The first electrode lead-out portion 251 is electrically connected to the end cover 22, and the second electrode lead-out portion 252 is electrically connected to the electrode terminal 24. This allows for the output or input of electrical energy to the electrode assembly 25 via the end cover 22 and the electrode terminal 24. On one hand, this reduces the number of electrode terminals 24 required, lowering costs, reducing the space occupied within the battery 100, and increasing energy density. On the other hand, once the information acquisition device is electrically connected to the end cover 22, it can collect usage information from the battery cell 20. This facilitates the connection of the information acquisition device to the battery cell 20 and data acquisition, reducing the difficulty of data acquisition from the battery cell 20.

[0194] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the first electrode lead-out portion 251 is welded to the end cap 22 to form a second solder mark portion 28. The minimum distance F between the second solder mark portion 28 and the insulating member 29 along a direction perpendicular to the thickness direction of the end cap 22 satisfies: F ≥ 2 mm.

[0195] F represents the minimum distance between the second solder mark 28 and the insulating member 29 along the direction perpendicular to the thickness direction of the end cap 22.

[0196] The minimum distance between the second solder mark 28 and the insulating part 29 along the direction perpendicular to the thickness direction of the end cap 22 can be: F = 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, etc.

[0197] By making the minimum distance between the second solder mark 28 and the insulating component 29 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 2mm, the distance between the second solder mark 28 and the insulating component 29 is larger, which helps to reduce the risk of the insulating component 29 being burned by high heat during welding, so that the insulating component 29 has a better insulation effect, reduces the risk of short circuit between the electrode terminal 24 and the end cap 22, and helps to improve the reliability of the battery cell 20.

[0198] Referring to Figures 3, 4, 5, 6 and 7, in some embodiments, the first electrode lead-out portion 251 is welded to the end cap 22 to form a second solder mark portion 28, which is an annular structure surrounding the electrode terminal 24.

[0199] The second solder mark 28 has a ring-shaped structure and is a closed shape extending along a closed trajectory. For example, the second solder mark 28 can be a circular, elliptical, square, hexagonal, or other closed shape. The electrode terminal 24 is disposed on the inner side of the second solder mark 28.

[0200] The second solder mark 28 has a ring structure and is arranged around the outside of the electrode terminal 24. In this way, the first electrode lead-out part 251 can be stably connected to the end cover 22 and has a large flow area.

[0201] Referring to Figures 8, 9, 10 and 11, in some embodiments, the first solder mark 27 is a ring structure.

[0202] The first solder mark 27 is an annular structure, and the first solder mark 27 is a closed shape extending along a closed trajectory. The shape of the first solder mark 27 matches the shape of the opening 211 of the housing 21. For example, when the opening 211 of the housing 21 is circular, the first solder mark 27 is also circular. Or, for example, when the opening 211 of the housing 21 is square, the first solder mark 27 is also square.

[0203] When the first solder mark 27 is an annular structure, the end cap 22 is welded to the housing 21 around its circumference, resulting in a high connection strength between the end cap 22 and the housing 21. In addition, the first solder mark 27 can seal the end cap 22 and the housing 21, reducing the risk of external impurities entering the housing 21 and reducing the risk of electrolyte leakage inside the housing 21.

[0204] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the weak part 231 is a ring structure.

[0205] The weak portion 231 has a ring-shaped structure and is a closed shape extending along a closed trajectory. For example, the weak portion 231 can be a circular, elliptical, square, hexagonal, or other closed shape. The electrode terminal 24 is disposed on the inner side of the weak portion 231.

[0206] By setting the weak part 231 as a ring structure, when the battery cell 20 is depressurized, the depressurization mechanism 23 can split along the weak part 231, thereby opening a larger opening 211, which facilitates the rapid depressurization of the battery cell 20.

[0207] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the pressure relief mechanism 23 is provided with a pressure relief groove 232, and the pressure relief mechanism 23 forms a weak part 231 in the area where the pressure relief groove 232 is provided.

[0208] The pressure relief mechanism 23 has a first surface and a second surface that are disposed opposite to each other in the thickness direction of the end cap 22. The first surface is provided with a pressure relief groove 232, that is, the pressure relief groove 232 is recessed from the first surface toward the second surface.

[0209] Along the thickness direction of the end cap 22, the weak part 231 is the part of the pressure relief mechanism 23 located between the bottom surface of the pressure relief groove 232 furthest from the first surface and the second surface.

[0210] The pressure relief groove 232 can be formed by various methods, such as stamping or cold heading. Taking the stamping method as an example, the pressure relief groove 232 can be stamped on the pressure relief mechanism 23 along the direction from the first surface to the second surface.

[0211] By using stamping or cold forging to form the pressure relief groove 232, the groove wall of the pressure relief groove 232 undergoes work hardening (the grain arrangement changes, leading to lattice distortion, reducing the metal's plasticity, and increasing the material's hardness), which enhances its resistance to external impacts and makes it less susceptible to damage from external impacts. This helps reduce the risk of leakage from the pressure relief mechanism 23.

[0212] The weak part 231 is formed by opening a pressure relief groove 232 on the pressure relief mechanism 23, which is simple, convenient and low cost.

[0213] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the pressure relief groove 232 is provided on the surface of the pressure relief mechanism 23 away from the interior of the housing 21.

[0214] The first surface is the surface of the pressure relief mechanism 23 that is away from the inside of the housing 21, and the second surface is the surface of the pressure relief mechanism 23 that faces the inside of the housing 21.

[0215] The first surface is the surface of the pressure relief mechanism 23 that faces away from the interior of the housing 21, i.e., the outer surface of the pressure relief mechanism 23. The second surface is the surface of the pressure relief mechanism 23 that faces the interior of the housing 21, i.e., the inner surface of the pressure relief mechanism 23. In short, the pressure relief groove 232 is provided on the outer surface of the pressure relief mechanism 23.

[0216] By setting the pressure relief groove 232 on the surface of the pressure relief mechanism 23 away from the inside of the housing 21, the tension that the weak part 231 needs to overcome when it cracks is smaller, making it easier to crack.

[0217] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the pressure relief mechanism 23 is integrally formed with the end cap 22.

[0218] One-piece molding means that the end cap 22 and the pressure relief mechanism 23 are provided as a single structure. For example, the pressure relief mechanism 23 can be formed on the end cap 22 by means of stamping or cold forging.

[0219] The pressure relief mechanism 23 and the end cap 22 are integrally formed, eliminating the need for additional welding or bonding processes, which helps reduce the risk of leakage from the pressure relief mechanism 23. Furthermore, during production, it is easier to ensure that the detonation pressure of multiple battery cells 20 produced is more consistent.

[0220] According to some embodiments of this application, the end cap 22 is made of steel.

[0221] For example, the end cap 22 can be made of carbon steel, alloy steel or stainless steel, etc.

[0222] In this embodiment, by setting the end cap 22 to be made of steel, the end cap 22 made of steel has better strength due to the high strength of steel. This allows the end cap 22 to be made thinner under a certain burst pressure of the battery cell 20, which helps to save space occupied by the end cap 22.

[0223] In some embodiments, the steel material is carbon steel or stainless steel.

[0224] For example, carbon steel can be low-carbon steel, medium-carbon steel, or high-carbon steel.

[0225] In this embodiment, carbon steel or stainless steel is used as the material for the end cap 22, which is low in cost and easy to manufacture.

[0226] In some embodiments, the end cap 22 is made of aluminum alloy.

[0227] It is understood that in embodiments where the pressure relief mechanism 23 and the end cap 22 are integrally formed, the material of the pressure relief mechanism 23 includes aluminum alloy.

[0228] Aluminum alloys are lightweight and have good ductility, making it easier to machine the pressure relief groove 232 on the pressure relief mechanism 23. In the embodiment where the pressure relief mechanism 23 and the end cap 22 are integrally formed, the end cap 22 is made of aluminum alloy, which can effectively reduce the molding difficulty of the end cap 22.

[0229] In some embodiments, the aluminum alloy comprises the following components in weight percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other individual elements ≤ 0.03%.

[0230] This aluminum alloy belongs to the tri-series aluminum alloy. The aluminum alloy has lower hardness and better formability, which reduces the processing difficulty of the pressure relief groove 232, helps to improve the processing accuracy of the pressure relief groove 232, and improves the pressure relief consistency of the pressure relief mechanism 23.

[0231] In some embodiments, the aluminum alloy comprises the following components by mass percentage: aluminum ≥ 96.7%, copper ≤ 0.05% ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other individual element components ≤ 0.05%, and other element total components ≤ 0.15%.

[0232] This aluminum alloy belongs to the five-series aluminum. Pressure relief mechanisms made from this aluminum alloy have higher hardness, greater strength, and better resistance to damage.

[0233] In other embodiments, the pressure relief mechanism 23 is separately disposed from the end cap 22, the end cap 22 is provided with a pressure relief hole, and the pressure relief mechanism 23 is installed on the end cap 22 and covers the pressure relief hole.

[0234] The phrase "pressure relief mechanism 23 and end cap 22 are separately configured, end cap 22 is provided with a pressure relief hole, and pressure relief mechanism 23 is installed on end cap 22 and covers the pressure relief hole" means that during manufacturing, a pressure relief hole is provided on end cap 22, and pressure relief mechanism 23 and end cap 22 are provided separately and ultimately connected together. For example, pressure relief mechanism 23 can be welded to end cap 22. Pressure relief mechanism 23 can be an explosion-proof plate installed on end cap 22.

[0235] The pressure relief mechanism 23 is separately set and installed on the end cover 22 to facilitate processing and manufacturing.

[0236] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the housing 21 includes integrally formed sidewalls and bottom walls, that is, the housing 21 is manufactured using an integral forming process, such as stamping, casting or extrusion molding, etc. In other words, the sidewalls and bottom walls of the housing 21 are integral structures.

[0237] A sidewall surrounds the outer periphery of the bottom wall, with one end of the sidewall connected to the bottom wall and the other end of the sidewall forming an opening 211. An end cap 22 is welded to the sidewall to form a first weld mark 27.

[0238] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the battery cell 20 is a cylindrical battery cell 20, and the direction perpendicular to the thickness direction of the end cover 22 is the radial direction of the end cover 22.

[0239] This application embodiment also provides a battery 100, which includes the battery cell 20 described above.

[0240] This application embodiment also provides an electrical device, which includes the aforementioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0241] Please refer to Figures 3 to 11 for some embodiments of this application.

[0242] This application provides a battery cell 20, which includes a housing 21, an end cap 22, and a pressure relief mechanism 23. The housing 21 has an opening 211, and the end cap 22 closes the opening 211 and is welded to the housing 21 to form a first solder mark 27. The pressure relief mechanism 23 is disposed on the end cap 22 and includes a weak portion 231. The pressure relief mechanism 23 is configured to crack along at least a portion of the weak portion 231 when the battery cell 20 is depressurized. The minimum distance A between the weak portion 231 and the first solder mark 27 along a direction perpendicular to the thickness direction of the end cap 22 satisfies: A ≥ 2.5 mm. The housing 21 and the end cap 22 are welded to form the first solder mark 27, and the pressure relief mechanism 23 can crack along at least a portion of the weak portion 231 when the battery cell 20 is depressurized, thereby releasing the internal pressure of the battery cell 20. By ensuring that the minimum distance between the weak portion 231 and the first solder mark 27 in the direction perpendicular to the thickness of the end cap 22 is greater than or equal to 2.5 mm, it is beneficial to reduce the impact of high heat on the weak portion 231 during welding of the housing 21 and the end cap 22, reduce the risk of the weak portion 231 cracking prematurely, and improve the lifespan of the battery cell 20.

[0243] Along the thickness direction of the end cap 22, the end of the housing 21 with the opening 211 has a first end face 212, and the end cap 22 has a second end face facing the first end face 212. The first end face 212 and the second end face are welded together to form a first weld mark 27, satisfying: A≥3mm. When the first end face 212 and the second end face are welded to form the first weld mark 27, by making the minimum distance between the weak part 231 and the first weld mark 27 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 3mm, it is more beneficial to reduce the impact of high heat on the weak part 231 when welding the housing 21 and the end cap 22, which can further reduce the risk of premature cracking of the weak part 231 and is more beneficial to improving the life of the battery cell 20.

[0244] The outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form a first weld mark 27, satisfying: A≥3.5mm. When the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form the first weld mark 27, the high heat during welding is more likely to affect the weak part 231. Therefore, by making the minimum distance between the weak part 231 and the first weld mark 27 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 3.5mm, it is more beneficial to reduce the impact of the high heat during welding of the housing 21 and the end cap 22 on the weak part 231, which can further reduce the risk of premature cracking of the weak part 231 and is more beneficial to improving the life of the battery cell 20.

[0245] The battery cell 20 includes an electrode assembly 25, which is housed within a casing 21. The electrode assembly 25 includes a first electrode lead-out portion 251, which is welded to an end cap 22 to form a second solder mark portion 28. Along a direction perpendicular to the thickness of the end cap 22, the minimum distance B between the weak portion 231 and the second solder mark portion 28 satisfies: B ≥ 3 mm. The first electrode lead-out portion 251 is electrically connected to the end cap 22, enabling the output of electrical energy from the electrode assembly 25 or the input of electrical energy to the electrode assembly 25 through the end cap 22. The welding of the first electrode lead-out portion 251 to the end cap 22 to form the second solder mark portion 28, by ensuring that the minimum distance between the weak portion 231 and the second solder mark portion 28 along a direction perpendicular to the thickness of the end cap 22 is greater than or equal to 3 mm, helps reduce the impact of high heat during welding of the first electrode lead-out portion 251 and the end cap 22 on the weak portion 231, reducing the risk of premature cracking of the weak portion 231 and improving the lifespan of the battery cell 20.

[0246] The battery cell 20 includes an electrode assembly 25, which is housed within a casing 21. The electrode assembly 25 includes a first electrode lead-out portion 251, which is welded to an end cap 22 to form a second solder mark portion 28. The end cap 22 has a thickness of T. The minimum distance between the first solder mark portion 27 and the second solder mark portion 28 along a direction perpendicular to the thickness of the end cap 22 is C, satisfying C ≥ 1.5T. When the end cap 22 is thicker, welding the first electrode lead-out portion 251 and the end cap 22 requires more heat, which will have a greater impact on the structure surrounding the second solder mark portion 28. By ensuring that the minimum distance between the first solder mark portion 27 and the second solder mark portion 28 along a direction perpendicular to the thickness of the end cap 22 is greater than or equal to 1.5 times the thickness of the end cap 22, a larger gap is achieved between the first solder mark portion 27 and the second solder mark portion 28. This helps reduce the risk of local deformation of the end cap 22, decreases stress concentration, and improves welding quality.

[0247] Along the thickness direction of the end cap 22, the end of the housing 21 with the opening 211 has a first end face 212, and the end cap 22 has a second end face facing the first end face 212. The first end face 212 and the second end face are welded together to form a first weld mark 27, satisfying: C≥2T. When the first end face 212 and the second end face are welded to form the first weld mark 27, by making the minimum distance between the first weld mark 27 and the second weld mark 28 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to twice the thickness of the end cap 22, a larger gap is achieved between the first weld mark 27 and the second weld mark 28, which is more conducive to reducing the risk of local deformation of the end cap 22, reducing stress concentration, and improving welding quality.

[0248] The outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form a first weld mark 27, satisfying: C≥3T. When the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form the first weld mark 27, by making the minimum distance between the first weld mark 27 and the second weld mark 28 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 3 times the thickness of the end cap 22, a larger gap is achieved between the first weld mark 27 and the second weld mark 28, which is more conducive to reducing the risk of local deformation of the end cap 22, reducing stress concentration, and improving welding quality.

[0249] The battery cell 20 includes an insulator 29 and an electrode terminal 24. The electrode terminal 24 is disposed on an end cap 22, and the insulator 29 is disposed between the electrode terminal 24 and the end cap 22 to insulate and isolate the electrode terminal 24 from the end cap 22. The minimum distance E between the first solder mark 27 and the insulator 29 along the direction perpendicular to the thickness of the end cap 22 satisfies: E ≥ 1.5 mm. By ensuring that the minimum distance between the first solder mark 27 and the insulator 29 along the direction perpendicular to the thickness of the end cap 22 is greater than or equal to 1.5 mm, the distance between the first solder mark 27 and the insulator 29 is relatively large. This helps reduce the risk of the insulator 29 being burned by high heat during welding, resulting in better insulation performance of the insulator 29, reducing the risk of short circuit between the electrode terminal 24 and the end cap 22, and improving the reliability of the battery cell 20.

[0250] Along the thickness direction of the end cap 22, the end of the housing 21 with the opening 211 has a first end face 212, and the end cap 22 has a second end face facing the first end face 212. The first end face 212 and the second end face are welded together to form a first solder mark 27, satisfying: E≥2mm. When the first end face 212 and the second end face are welded to form the first solder mark 27, by making the minimum distance between the first solder mark 27 and the insulating member 29 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 2mm, the distance between the first solder mark 27 and the insulating member 29 is larger, which is more conducive to reducing the risk of high heat burning the insulating member 29 during welding, so that the insulating member 29 has a better insulation effect, further reducing the risk of short circuit between the electrode terminal 24 and the end cap 22, and improving the reliability of the battery cell 20.

[0251] The outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form a first weld mark 27, satisfying E≥2.5mm. When the outer peripheral surface of the end cap 22 is welded to the inner peripheral surface of the housing 21 to form the first weld mark 27, the high heat during welding is more likely to affect the insulating component 29. Therefore, by making the minimum distance between the first weld mark 27 and the insulating component 29 in the direction perpendicular to the thickness direction of the end cap 22 greater than or equal to 2.5mm, the distance between the first weld mark 27 and the insulating component 29 is larger, which is more conducive to reducing the risk of the high heat during welding burning the insulating component 29, so that the insulating component 29 has a better insulation effect, further reducing the risk of short circuit between the electrode terminal 24 and the end cap 22, which is conducive to improving the reliability of the battery cell 20.

[0252] The battery cell 20 includes an insulator 29 and an electrode terminal 24. The electrode terminal 24 is disposed on an end cap 22, and the insulator 29 is disposed between the electrode terminal 24 and the end cap 22 to insulate and isolate the electrode terminal 24 from the end cap 22. The minimum distance D between the weak portion 231 and the insulator 29 along the direction perpendicular to the thickness of the end cap 22 satisfies: D ≥ 4 mm. By making the minimum distance between the weak portion 231 and the insulator 29 along the direction perpendicular to the thickness of the end cap 22 greater than or equal to 4 mm, the distance between the weak portion 231 and the insulator 29 is larger, which reduces the inhibitory effect of the insulator 29 on the deformation of the weak portion 231. This facilitates the timely cracking of the weak portion 231 when the battery cell 20 is depressurized, improving the timeliness of depressurization of the battery cell 20.

[0253] The battery cell 20 includes an electrode assembly 25, an insulator 29, and electrode terminals 24. The electrode assembly 25 is housed within a housing 21 and includes a first electrode lead-out portion 251 and a second electrode lead-out portion 252. The first electrode lead-out portion 251 and the second electrode lead-out portion 252 have opposite polarities. The first electrode lead-out portion 251 is electrically connected to an end cap 22. The electrode terminals 24 are disposed on the end cap 22 and are electrically connected to the second electrode lead-out portion 252. The insulator 29 is disposed between the electrode terminals 24 and the end cap 22 to insulate and isolate the electrode terminals 24 from the end cap 22. The first electrode lead-out portion 251 is welded to the end cap 22 to form a second solder mark portion 28. The minimum distance between the second solder mark portion 28 and the insulator 29 along a direction perpendicular to the thickness direction of the end cap 22 is F, which satisfies: F≥2mm. The first electrode lead-out portion 251 is electrically connected to the end cap 22, and the second electrode lead-out portion 252 is electrically connected to the electrode terminal 24. This allows for the output or input of electrical energy from the electrode assembly 25 through the end cap 22 and the electrode terminal 24. On one hand, this reduces the number of electrode terminals 24 required, lowering costs, reducing the space occupied within the battery 100, and increasing energy density. On the other hand, once the information acquisition device is electrically connected to the end cap 22, it can collect usage information from the battery cell 20, facilitating connection and data acquisition and reducing the difficulty of data collection from the battery cell 20. By ensuring that the minimum distance between the second solder mark portion 28 along the direction perpendicular to the thickness of the end cap 22 and the insulating member 29 is greater than or equal to 2mm, the distance between the second solder mark portion 28 and the insulating member 29 is relatively large. This reduces the risk of high heat burning the insulating member 29 during soldering, resulting in better insulation performance and reducing the risk of short circuits between the electrode terminal 24 and the end cap 22, thus improving the reliability of the battery cell 20.

[0254] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, wherein, include: The shell has an opening; An end cap is provided to close the opening and is welded to the housing to form a first weld mark. A pressure relief mechanism is provided on the end cap, the pressure relief mechanism including a weak portion, the weak portion being configured to at least partially crack when the battery cell is depressurized; Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the weak part and the first solder mark is A, which satisfies: A≥2.5mm.

2. The battery cell according to claim 1, wherein, Along the thickness direction of the end cap, the end of the housing with the opening has a first end face, and the end cap has a second end face facing the first end face. The first end face and the second end face are welded together to form the first weld mark, satisfying: A≥3mm.

3. The battery cell according to claim 1, wherein, The outer peripheral surface of the end cap is welded to the inner peripheral surface of the housing to form the first weld mark, satisfying: A≥3.5mm.

4. The battery cell according to any one of claims 1-3, wherein, The battery cell includes an electrode assembly, which is housed within the housing. The electrode assembly includes a first electrode lead-out portion, which is welded to the end cap to form a second solder mark portion. Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the weak part and the second solder mark is B, which satisfies: B≥3mm.

5. The battery cell according to claim 4, wherein, The first electrode lead-out portion includes a first electrode tab and a first current collector. The first current collector is electrically connected to the first electrode tab and the end cap. The first current collector is welded to the end cap to form the second solder mark portion.

6. The battery cell according to claim 5, wherein, The first current collector is welded to the end cap to form the second weld mark.

7. The battery cell according to claim 1, wherein, The battery cell includes an electrode assembly, which is housed within the housing. The electrode assembly includes a first electrode lead-out portion, which is welded to the end cap to form a second solder mark portion. The thickness of the end cap is T; Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the first solder mark and the second solder mark is C, which satisfies: C≥1.5T.

8. The battery cell according to claim 7, wherein, Along the thickness direction of the end cap, the end of the housing with the opening has a first end face, and the end cap has a second end face facing the first end face. The first end face and the second end face are welded together to form the first weld mark, satisfying: C≥2T.

9. The battery cell according to claim 7, wherein, The outer peripheral surface of the end cap is welded to the inner peripheral surface of the housing to form the first weld mark, satisfying: C≥3T.

10. The battery cell according to claim 1, wherein, The battery cell includes an insulating component and an electrode terminal. The electrode terminal is disposed on the end cap, and the insulating component is disposed between the electrode terminal and the end cap to insulate and isolate the electrode terminal from the end cap. Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the first solder mark and the insulating part is E, which satisfies: E≥1.5mm.

11. The battery cell according to claim 10, wherein, Along the thickness direction of the end cap, the end of the housing with the opening has a first end face, and the end cap has a second end face facing the first end face. The first end face and the second end face are welded together to form the first weld mark portion, satisfying: E≥2mm.

12. The battery cell according to claim 10, wherein, The outer peripheral surface of the end cap is welded to the inner peripheral surface of the housing to form the first weld mark, satisfying: E≥2.5mm.

13. The battery cell according to any one of claims 1-12, wherein, The battery cell includes an insulating component and an electrode terminal. The electrode terminal is disposed on the end cap, and the insulating component is disposed between the electrode terminal and the end cap to insulate and isolate the electrode terminal from the end cap. Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the weak part and the insulating member is D, which satisfies: D≥4mm.

14. The battery cell according to any one of claims 1-13, wherein, The battery cell includes an electrode assembly, an insulating component, and electrode terminals. The electrode assembly is housed within the housing. The electrode assembly includes a first electrode lead and a second electrode lead, which have opposite polarities. The first electrode lead is electrically connected to the end cap. The electrode terminals are disposed on the end cap and electrically connected to the second electrode lead. The insulating component is disposed between the electrode terminals and the end cap to insulate and isolate the electrode terminals from the end cap.

15. The battery cell according to claim 14, wherein, The first electrode lead-out portion is welded to the end cap to form a second solder mark portion. Along the direction perpendicular to the thickness direction of the end cap, the minimum distance between the second solder mark portion and the insulating component is F, which satisfies: F≥2mm.

16. The battery cell according to claim 14 or 15, wherein, The first electrode lead-out portion is welded to the end cap to form a second solder mark portion, which is an annular structure surrounding the electrode terminal.

17. The battery cell according to any one of claims 1-16, wherein, The first solder mark is a ring structure.

18. The battery cell according to any one of claims 1-17, wherein, The weak point is a ring structure.

19. The battery cell according to any one of claims 1-18, wherein, The pressure relief mechanism is provided with a pressure relief groove, and the pressure relief mechanism forms the weak part in the area where the pressure relief groove is provided.

20. The battery cell according to claim 19, wherein, The pressure relief groove is located on the surface of the pressure relief mechanism that is away from the interior of the housing.

21. The battery cell according to any one of claims 1-20, wherein, The pressure relief mechanism is integrally formed with the end cap.

22. The battery cell according to any one of claims 1-20, wherein, The pressure relief mechanism is separately disposed from the end cap. The end cap is provided with a pressure relief hole, and the pressure relief mechanism is installed on the end cap and covers the pressure relief hole.

23. The battery cell according to any one of claims 1-22, wherein, The battery cell is a cylindrical battery cell, and the direction perpendicular to the thickness direction of the end cap is the radial direction of the end cap.

24. A battery, wherein, Includes the battery cell according to any one of claims 1-23.

25. An electrical appliance, wherein, Includes a battery cell according to any one of claims 1-23, the battery cell being used to provide electrical energy to the electrical equipment.

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