Battery cell, battery, and electric device

Abstract

The application discloses a battery cell, a battery and a power utilization device. The battery cell comprises a shell and an electrode terminal. The shell comprises a wall part, and the wall part is provided with a lead-out hole. The electrode terminal is arranged in the lead-out hole, and the electrode terminal is provided with a weak area. The weak area is configured to be broken when the internal pressure of the shell exceeds a pressure threshold or the temperature exceeds a temperature threshold, so that the inside of the shell is in communication with the outside of the shell. In this way, the risk of explosion of the battery cell can be reduced.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to battery cells, batteries, and electrical devices. Background Technology

[0002] With the development of battery technology, battery cells are being applied in more and more fields, gradually replacing traditional fossil fuels in the automotive power sector. Battery cells can store chemical energy and controllably convert it into electrical energy. In recyclable battery cells, the active materials can be reactivated through charging after discharge, allowing for continued use.

[0003] A single battery cell typically includes electrode assemblies, electrode terminals, and a casing. The electrode assemblies are electrically connected to the outside environment via the electrode terminals. The casing houses and supports the electrode assemblies. The casing contains electrolyte; the electrolyte and active materials on the electrode assemblies can generate gas, causing an increase in internal pressure and potentially leading to the battery cell bursting. Utility Model Content

[0004] In view of the above problems, this application provides a battery cell, a battery, and an electrical device that can reduce the risk of battery cell explosion.

[0005] In a first aspect, this application provides a battery cell, which includes a casing and electrode terminals. The casing includes a wall portion with lead-out holes. The electrode terminals are located at the lead-out holes and have weak regions configured to be damaged when the internal pressure of the casing exceeds a pressure threshold or the temperature exceeds a temperature threshold, thereby enabling communication between the interior and exterior of the casing.

[0006] In this way, when the pressure exceeds the pressure threshold or the temperature exceeds the temperature threshold, the weak area is damaged, and excess gas inside the casing is released, thereby reducing the risk of the battery cell bursting due to excessive internal pressure. Compared to placing the weak area in the casing, placing it at the electrode terminals reduces the possibility of casing deformation and facilitates the assembly of the battery cell.

[0007] In some embodiments, the electrode terminals are provided with grooves, and the weak area forms the bottom of the grooves.

[0008] The above method facilitates the processing of weak areas. When the pressure exceeds the pressure threshold or the temperature exceeds the temperature threshold, the electrode terminals can break or bend along the groove under the action of pressure, and the excess gas inside the casing can be discharged, thereby reducing the risk of the battery cell exploding due to excessive internal pressure.

[0009] In some embodiments, the electrode terminal includes an insertion portion and a first flange portion connected to each other. The insertion portion is inserted into the lead-out hole along the axial direction of the electrode terminal. In the radial direction of the electrode terminal, the outer peripheral surface of the first flange portion at least partially extends beyond the outer peripheral surface of the insertion portion. A portion of the first flange portion located at the periphery of the lead-out hole is supported on the side of the wall portion facing the interior of the housing. A weak area is provided on the insertion portion and / or the first flange portion.

[0010] By means of the above method, since the pressure inside the shell exerts a relatively large force on the insertion part and the first flange part, by setting the weak area on the insertion part or the first flange part, the weak area can be made more sensitive to the pressure inside the shell, and it is easier to achieve the explosion-proof effect.

[0011] In some embodiments, the electrode terminal is provided with a groove, the weak area forming the bottom of the groove, and the groove is disposed on the side surface of the first flange facing and / or away from the wall.

[0012] The above method facilitates the processing of weak areas. In addition, the thickness of the first flange in the above-mentioned axial direction is relatively thin, so the groove is more sensitive to the internal pressure of the shell and is more likely to achieve the explosion-proof effect.

[0013] In some embodiments, the groove is at least partially opposite to the matching slot between the outer peripheral surface of the insertion portion and the wall of the lead-out hole along the axial direction.

[0014] Using the above method, when the electrode terminal breaks or bends along the groove, it is easier to detach from the lead-out hole, which can quickly release pressure and more easily achieve the explosion-proof effect.

[0015] In some embodiments, the radial width of the matching seam is greater than the radial width of the notch groove.

[0016] Using the above method, when the electrode terminal breaks or bends along the groove, it is easier to detach from the lead-out hole, which can quickly release pressure and more easily achieve the explosion-proof effect.

[0017] In some embodiments, the outermost edge of the groove in the radial direction is projected axially into the mating seam.

[0018] Using the above method, when the electrode terminal breaks or bends along the groove, it is easier to detach from the lead-out hole, which can quickly release pressure and more easily achieve the explosion-proof effect.

[0019] In some embodiments, the radial width of the groove is greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0020] In the radial direction, setting the radial width of the groove to be greater than or equal to 0.5 mm facilitates bending or breakage of the first flange along the groove when the internal pressure or temperature exceeds the pressure threshold. Setting the radial width of the groove to be less than or equal to 2 mm ensures that the first flange maintains sufficient structural strength, improving the structural stability of the battery cell.

[0021] In some embodiments, the axial depth of the groove is greater than or equal to 0.1 times the axial thickness of the first flange and less than or equal to 0.9 times the axial thickness of the first flange.

[0022] In the axial direction, by setting the axial depth of the groove to 0.1 times the axial thickness H0 of the first flange 230, it is beneficial to promote bending or breakage of the first flange along the groove when the internal pressure or temperature of the casing exceeds the pressure threshold or temperature threshold. By setting the axial depth of the groove to less than or equal to 0.9 times the axial thickness of the first flange, the first flange can maintain sufficient structural strength, improving the structural stability of the battery cell.

[0023] In some embodiments, the weak area is at least partially located on the outer peripheral surface of the insertion portion.

[0024] The above method facilitates the processing of weak areas and makes it easier for the insertion part to break along the weak areas.

[0025] In some embodiments, the electrode terminal includes an insertion portion and a sealing portion connected to each other. The insertion portion is inserted into the lead-out hole along the axial direction of the electrode terminal and is cylindrical in shape. The sealing portion seals the end of the insertion portion facing the inside of the housing to form a recessed portion, and a weak area is provided on the sealing portion.

[0026] By employing the above method, since the thickness of the sealing portion in the aforementioned axial direction is relatively thin, the weak area is more sensitive to the internal pressure of the casing, making it easier to achieve an explosion-proof effect. Furthermore, it allows gas from inside the casing to enter the recess and exit through it.

[0027] In some embodiments, the sealing portion is welded to the insertion portion to form a weld mark, and the weak area is located within the weld mark.

[0028] By using the above methods, the solder mark can be used as a weak area, which can simplify the manufacturing process of the battery cell.

[0029] In some embodiments, the weak zone is arranged in a ring around the central axis of the outlet hole.

[0030] By using the above methods, the weak areas can be made more sensitive to the internal pressure of the outer shell, thus achieving a better explosion-proof effect.

[0031] In some embodiments, the electrode terminal includes an insertion portion and a sealing portion connected to each other. The insertion portion is inserted into the lead-out hole along the axial direction of the electrode terminal and is cylindrical in shape. The sealing portion seals the end of the insertion portion facing the inside of the housing to form a recess. The battery cell includes a sealing member for sealing the recess. The battery cell is electrically connected to the outside through the sealing member.

[0032] By using the above method to seal the recessed area with a sealing component and connect it to the external electrical system, the connection area between the battery cell and external devices can be increased.

[0033] In some embodiments, the recess is used to inject electrolyte into the interior of the housing.

[0034] The above methods can simplify the structural complexity of battery cells, reduce electrolyte leakage during assembly, and improve the assembly efficiency of battery cells.

[0035] In some embodiments, the sealing portion is provided with an injection hole that connects the interior of the housing with the recessed portion.

[0036] The above method facilitates sealing after electrolyte injection, reducing the risk of electrolyte leakage.

[0037] In some embodiments, the battery cell further includes a current collector and an electrode assembly disposed inside the housing. The current collector is used to connect the tabs and electrode terminals of the electrode assembly, and the side of the sealing portion opposite to the recess is welded to the current collector.

[0038] By utilizing the thinness of the sealing part and welding it to the manifold in the above manner, it is easy to achieve electrical connection between the electrode terminal and the manifold from the side of the electrode terminal away from the manifold.

[0039] In some embodiments, the battery cell includes an electrode assembly, the housing includes a housing and an end cap, one end of the housing has an opening, the end cap closes to the opening, the housing includes a side wall and an end wall, the side wall surrounds the outside of the electrode assembly, the end wall is disposed opposite to the opening, and the wall portion is an end cap or an end wall.

[0040] By placing the electrode terminals on the end cap or end wall in the above manner, the assembly efficiency of the battery cell can be improved, and the possibility of deformation of the end cap or end wall can be reduced, which facilitates the assembly of the battery cell.

[0041] In some embodiments, the melting point of the electrode terminal material is lower than the melting point of the housing material.

[0042] In this way, when welding the electrode terminals to other components, the lower melting point of the electrode terminal material helps to reduce the welding temperature, while the relatively higher melting point of the outer shell material can reduce the adverse effects of the welding process on the outer shell, thereby reducing the risk of leakage.

[0043] In some embodiments, the difference between the melting point of the housing material and the melting point of the electrode terminal material is greater than 300°C.

[0044] By using the above method, when welding the electrode terminals to other components, it is beneficial to reduce the welding temperature and reduce the adverse effects of the welding process on the casing, thereby reducing the risk of leakage.

[0045] In some embodiments, the housing is made of steel, and the electrode terminals are made of aluminum or copper.

[0046] Using the methods described above, steel as the outer casing material results in a lower coefficient of thermal expansion and good mechanical strength. Copper or aluminum has a lower melting point than steel, making the electrode terminals easier to weld, and copper or aluminum is also easier to process and shape.

[0047] Secondly, this application provides a battery, which includes the aforementioned battery cell.

[0048] Thirdly, this application provides an electrical device that includes the aforementioned battery.

[0049] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0050] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0051] Figure 1 This is a schematic diagram of the structure of a vehicle according to one or more embodiments;

[0052] Figure 2 This is an exploded structural diagram of a battery according to one or more embodiments;

[0053] Figure 3 This is a cross-sectional structural diagram of a battery cell according to one or more embodiments;

[0054] Figure 4 for Figure 3 The diagram shows a cross-sectional structure of a battery cell with some parts hidden.

[0055] Figure 5 for Figure 3 The diagram shows a bottom view of the battery cell with some parts hidden.

[0056] Figure 6 for Figure 4 A schematic diagram of the structure of part A of the battery cell after some parts are hidden.

[0057] Figure 7 This is a partial structural schematic diagram of a battery cell according to one or more embodiments;

[0058] Figure 8 This is a partial structural schematic diagram of a battery cell according to one or more embodiments;

[0059] Figure 9 This is a partial structural schematic diagram of a battery cell according to one or more embodiments;

[0060] Figure 10 This is a partial structural schematic diagram of a battery cell according to one or more embodiments.

[0061] The reference numerals in the detailed embodiments are as follows:

[0062] 1000a vehicles;

[0063] 100A battery; 200A controller; 300A motor;

[0064] 10a Enclosure; 11a First Section; 12a Second Section;

[0065] The radial width of the D1 groove; the radial width of the D2 matching seam; the axial thickness of the H0 first flange; the axial depth of the H1 groove;

[0066] 1. Battery cell; 100. Housing; 101. Wall; 102. Lead-out hole; 200. Electrode terminal; 210. Score groove; 211. Weak area; 220. Insertion part; 230. First flange part; 240. Matching seam; 250. Sealing part; 260. Recessed part; 270. Second flange part; 300. Sealing component; 251. Injection hole; 400. Collector plate; 500. Electrode assembly; 501. Tab; 110. Housing; 120. End cap; 111. Opening; 112. Side wall; 113. End wall; 600. Insulator; 700. Solder mark. Detailed Implementation

[0067] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein 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 specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0069] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0070] In this document, the term "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 throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0071] In the description of the embodiments 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, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0072] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0073] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0074] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0075] With the development of battery technology, battery cells are being applied in more and more fields, gradually replacing traditional fossil fuels in the automotive power sector. Battery cells can store chemical energy and controllably convert it into electrical energy. In recyclable battery cells, the active materials can be reactivated through charging after discharge, allowing for continued use.

[0076] A single battery cell typically includes electrode assemblies, electrode terminals, and a casing. The electrode assemblies are electrically connected to the outside environment via the electrode terminals. The casing houses and supports the electrode assemblies. The casing contains electrolyte; the electrolyte and active materials on the electrode assemblies can generate gas, causing an increase in internal pressure and potentially leading to the battery cell bursting.

[0077] To reduce the risk of battery cell explosion, this application incorporates a weak point at the electrode terminals. This weak point is configured to allow communication between the interior and exterior of the casing when the internal pressure or temperature exceeds a pressure threshold or a temperature threshold. Compared to placing the weak point on the casing itself, placing it at the electrode terminals reduces the likelihood of casing deformation and facilitates battery cell assembly.

[0078] Based on the above considerations, this application provides a battery cell, a battery, and an electrical device. When the pressure exceeds a pressure threshold or the temperature exceeds a temperature threshold, the electrode terminals can break or bend along the weak area under the action of pressure or high temperature, allowing excess gas inside the casing to escape, thereby reducing the risk of the battery cell exploding due to excessive internal pressure. By setting the weak area on the insertion part or the first flange part, the weak area can be made more sensitive to the pressure inside the casing, making it easier to achieve an explosion-proof effect. In this way, the risk of battery cell exploding can be reduced.

[0079] The battery cell, battery, and electrical device disclosed in this application can be used in electrical devices that use batteries as a power source or in various energy storage systems that use batteries as energy storage elements. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., while spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0080] For ease of explanation, the following embodiments will be described using a vehicle 1000a as an example of an electrical device according to an embodiment of this application.

[0081] Please refer to Figure 1 Vehicle 1000a 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 100a is internally installed in vehicle 1000a, and the battery 100a can be located at the bottom, front, or rear of vehicle 1000a. The battery 100a can be used to power vehicle 1000a; for example, the battery 100a can serve as the operating power source for vehicle 1000a. Vehicle 1000a may also include a controller 200a and a motor 300a. The controller 200a is used to control the battery 100a to supply power to the motor 300a, for example, to meet the power needs of vehicle 1000a during starting, navigation, and driving.

[0082] In some embodiments of this application, the battery 100a can not only serve as the operating power source for the vehicle 1000a, but also as the driving power source for the vehicle 1000a, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000a.

[0083] In some embodiments, battery 100a may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0084] The battery 100a mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells 1 to provide higher voltage and capacity.

[0085] In this embodiment, each battery cell 1 can be a secondary battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. Each battery cell 1 can also be a primary battery.

[0086] Battery cell 1 includes, but is not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc. Battery cell 1 may be cylindrical, flat, cuboid, or other shapes.

[0087] In some embodiments, the battery 100a can be a battery module. When there are multiple battery cells 1, the multiple battery cells 1 are arranged and fixed to form a battery module.

[0088] In some embodiments, please refer to Figure 2 The battery 100a can be a battery pack, which includes a housing 10a and a battery cell 1, with the battery cell 1 or battery module housed in the housing 10a.

[0089] In some embodiments, the housing 10a may be part of the chassis structure of the vehicle 1000a. For example, a portion of the housing 10a may be at least a portion of the floor of the vehicle 1000a, or a portion of the housing 10a may be at least a portion of the crossbeams and longitudinal beams of the vehicle 1000a.

[0090] Please refer to Figure 2 The battery 100a includes a housing 10a and a battery cell 1, with the battery cell 1 housed within the housing 10a. The housing 10a provides a space for the battery cell 1 and can have various structures. In some embodiments, the housing 10a may include a first portion 11a and a second portion 12a, which overlap each other, together defining a space for accommodating the battery cell 1. The second portion 12a may be a hollow structure with one open end, and the first portion 11a may be a plate-like structure, covering the open side of the second portion 12a so that the first portion 11a and the second portion 12a together define the space. Alternatively, both the first portion 11a and the second portion 12a may be hollow structures with one open side, with the open side of the first portion 11a covering the open side of the second portion 12a. Of course, the housing 10a formed by the first portion 11a and the second portion 12a can have various shapes, such as a cylinder or a cuboid.

[0091] In battery 100a, there can be multiple battery cells 1, which can be connected in series, parallel, or a combination thereof. A combination thereof means that multiple battery cells 1 are connected in both series and parallel. Multiple battery cells 1 can be directly connected in series, parallel, or a combination thereof, and then the entire assembly of the multiple battery cells 1 is housed within housing 10a. Alternatively, battery 100a can also consist of multiple battery cells 1 first connected in series, parallel, or a combination thereof to form a battery module, and then multiple battery modules connected in series, parallel, or a combination thereof to form a whole, which is also housed within housing 10a. Battery 100a may also include other structures; for example, battery 100a may also include a busbar component for realizing the electrical connection between multiple battery cells 1.

[0092] Please refer to Figure 3 In this embodiment, a cylindrical battery cell 1 is used as an example. The battery cell 1 includes a housing 100, an electrode assembly 500, and other functional components.

[0093] In some embodiments, the housing 100 is used to encapsulate the electrode assembly 500 and components such as the electrolyte. The housing 100 can be a steel housing, an aluminum housing, a plastic housing (such as a polypropylene housing), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film, etc.

[0094] The housing 100 may include an end cap 120 and a housing 110. The end cap 120 is a component that closes onto the opening 111 of the housing 110 to isolate the internal environment of the battery cell 1 from the external environment. Not limited to this, the shape of the end cap 120 may be adapted to the shape of the housing 110 to fit it. Optionally, the end cap 120 may be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 120 is less prone to deformation under pressure and impact, allowing the battery cell 1 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 200 may be provided on the end cap 120. The electrode terminals 200 can be used for electrical connection with the electrode assembly 500 for outputting or inputting electrical energy from the battery cell 1. In some embodiments, the end cap 120 may also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 1 reaches a threshold. The end cap 120 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, and plastic. In some embodiments, an insulating material can be provided on the inner side of the end cap 120. The insulating material can be used to isolate the electrical connection components within the housing 110 from the end cap 120 to reduce the risk of short circuits. For example, the insulating material can be plastic, rubber, etc.

[0095] The housing 110 is a component used to cooperate with the end cap 120 to form the internal environment of the battery cell 1. This internal environment can accommodate the electrode assembly 500, electrolyte, and other components. The housing 110 and the end cap 120 can be independent components. An opening 111 can be provided on the housing 110, and the end cap 120 can close the opening 111 to form the internal environment of the battery cell 1. Alternatively, the end cap 120 and the housing 110 can be integrated. Specifically, the end cap 120 and the housing 110 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 110, the end cap 120 closes the housing 110. The housing 110 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 110 can be determined according to the specific shape and size of the electrode assembly 500. The housing 110 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0096] Electrode assembly 500 is a component in the battery cell 1 where an electrochemical reaction occurs. The housing 110 may contain one or more electrode assemblies 500.

[0097] In some embodiments, the electrode assembly 500 includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, disposed between the positive and negative electrodes, serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0098] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0099] 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.

[0100] 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 or stainless steel with a silver surface treatment, 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.).

[0101] 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 positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate 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 manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, at least one of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also abbreviated as NCM333), LiNi0.5Co0.2Mn0.3O2 (also abbreviated as NCM523), LiNi0.5Co0.25Mn0.25O2 (also abbreviated as NCM211), LiNi0.6Co0.2Mn0.2O2 (also abbreviated as NCM622), LiNi0.8Co0.1Mn0.1O2 (also abbreviated as NCM811), lithium nickel cobalt aluminum oxides (such as LiNi0.85Co0.15Al0.05O2) and their modified compounds.

[0102] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0103] 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 electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, 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.).

[0104] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0105] 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.

[0106] 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.

[0107] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0108] In some embodiments, the electrode assembly 500 further includes an isolator disposed between the positive and negative electrodes.

[0109] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0110] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0111] 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.

[0112] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0113] Liquid electrolytes include electrolyte salts and solvents.

[0114] In some embodiments, the electrolyte salt may be selected from 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.

[0115] In some embodiments, the solvent may be selected from at least one of 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 of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0116] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0117] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0118] 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.

[0119] As an example, inorganic solid electrolytes can be 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 phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0120] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0121] In some embodiments, the electrode assembly 500 is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0122] In some embodiments, the electrode assembly 500 is provided with tabs 501, which can conduct current from the electrode assembly 500. The tabs include a positive tab and a negative tab. The positive and negative tabs can be located together at one end of the main body or at opposite ends of the main body. During the charging and discharging process of the battery 100a, the positive and negative active materials react with the electrolyte, and the tabs 501 connect to the electrode terminals to form a current loop.

[0123] According to some embodiments of this application, such as Figures 3 to 5 As shown, the battery cell 1 of this application includes a housing 100 and electrode terminals 200. The housing 100 includes a wall portion 101, and the wall portion 101 is provided with a lead-out hole 102. The electrode terminals 200 are disposed in the lead-out hole 102, and the electrode terminals 200 are provided with a weak area 211. The weak area 211 is configured to be damaged when the internal pressure of the housing 100 exceeds a pressure threshold or the temperature exceeds a temperature threshold, so that the interior of the housing 100 communicates with the exterior of the housing 100.

[0124] The electrode terminal 200 can be installed in the housing 100 by being inserted into the lead-out hole 102. Specifically, one end of the electrode terminal 200 is disposed facing the inside of the housing 100 and can be used to electrically connect to the electrode assembly 500 disposed inside the housing 100. The other end of the electrode terminal 200 is disposed facing the outside of the housing 100 and can be connected to the outside, thereby enabling the charging and discharging of the electrode assembly 500.

[0125] The interior of the casing 100 can contain electrolyte and active materials. The electrolyte and active materials can generate gas, causing the internal pressure of the casing 100 to rise. As the gas accumulates, the internal pressure of the casing 100 can rise to exceed a pressure threshold. By providing a weak region 211 on the electrode terminal 200, when the pressure exceeds the pressure threshold or the temperature exceeds the temperature threshold, the weak region 211 is destroyed, allowing communication between the interior and exterior of the casing 100, and enabling the excess gas inside the casing 100 to escape.

[0126] When the energy of a single battery cell 1 is released too quickly, it often causes the temperature inside the casing 100 to rise, and high temperature can promote the increase of pressure. When the temperature exceeds the temperature threshold, the weak area 211 can be damaged, which helps to alleviate the increase of pressure inside the casing 100.

[0127] This design can suppress the continuous increase of pressure inside the casing 100 and reduce the risk of the battery cell 1 exploding.

[0128] Optionally, the weak zone 211 may be damaged by pressure exceeding the load it can withstand. The weak zone 211 may also be damaged by high temperature, for example, by high temperature causing the strength of the weak zone 211 to decrease, or by high temperature causing the weak zone 211 to melt or deform.

[0129] In some embodiments, the electrode terminal 200 may completely break along the weak region 211, and the broken portion moves away from the interior of the housing 100 under pressure inside the housing 100. In other embodiments, the electrode terminal 200 may partially break along the weak region 211, and the broken portion bends away from the interior of the housing 100 under pressure inside the housing 100.

[0130] If the weak area 211 is located on the outer casing 100, for example, on the wall 101, it will weaken the structural strength of the outer casing 100, reduce its load-bearing capacity, and make it more susceptible to deformation, which is not conducive to the assembly of the battery cell 1. For example, the outer casing 100 may serve to support the electrode assembly 500; if the outer casing 100 is deformed, it will be difficult to assemble the electrode assembly 500. Therefore, by placing the weak area 211 on the electrode terminal 200, the possibility of deformation of the outer casing 100 can be reduced, facilitating the assembly of the battery cell 1.

[0131] According to some embodiments of this application, optionally, such as Figure 6 As shown, the electrode terminal 200 is provided with a groove 210, and the weak area 211 forms the bottom of the groove 210.

[0132] A weak area 211 can be formed on the electrode terminal 200 by forming a groove 210. When the pressure exceeds the pressure threshold or the temperature exceeds the temperature threshold, the electrode terminal 200 can break or bend along the groove 210 under the action of pressure or high temperature, and the excess gas inside the casing 100 can be discharged, thereby reducing the risk of the battery cell 1 exploding due to excessive internal pressure.

[0133] According to some embodiments of this application, optionally, such as Figure 6 As shown, the electrode terminal 200 includes an insertion portion 220 and a first flange portion 230 connected to each other. The insertion portion 220 is inserted into the lead-out hole 102 along the axial direction of the electrode terminal 200. In the radial direction of the electrode terminal 200, the outer peripheral surface of the first flange portion 230 at least partially extends beyond the outer peripheral surface of the insertion portion 220. The portion of the first flange portion 230 located on the periphery of the lead-out hole 102 is supported on the side of the wall portion 101 facing the interior of the outer casing 100. A weak area 211 is provided on the insertion portion 220 and / or the first flange portion 230.

[0134] The axial direction of electrode terminal 200 refers to the distance between the end of electrode terminal 200 facing the interior of housing 100 and the end facing away from the interior of housing 100, while the radial direction of electrode terminal 200 refers to the direction perpendicular to the axial direction of electrode terminal 200. Unless otherwise specified, the axial and radial directions mentioned below refer to the axial and radial directions of electrode terminal 200.

[0135] By arranging the insertion portion 220 to be inserted into the lead-out hole 102 along the axial direction of the electrode terminal 200, the electrode terminal 200 can be installed. By supporting the first flange portion 230 on the wall portion 101, the connection stability between the electrode terminal 200 and the wall portion 101 can be improved. In the radial direction of the electrode terminal 200, by arranging the outer peripheral surface of the first flange portion 230 to at least partially extend beyond the outer peripheral surface of the insertion portion 220, and by providing the first flange portion 230 inside the housing 100, the wall portion 101 can block the first flange portion 230, thereby restricting the electrode terminal 200 from detaching from the inside of the housing 100.

[0136] The weak point 211 can be provided on the insertion portion 220, the first flange portion 230, or both. By providing the weak point 211 on the insertion portion 220, when the pressure or temperature inside the housing 100 exceeds a pressure threshold or a temperature threshold, the insertion portion 220 can break or bend along the weak point 211, allowing excess gas inside the housing 100 to escape. Similarly, by providing the weak point 211 on the first flange portion 230, when the pressure or temperature inside the housing 100 exceeds a pressure threshold or a temperature threshold, the first flange portion 230 can break or bend along the weak point 211, allowing excess gas inside the housing 100 to escape.

[0137] Since the pressure inside the outer casing 100 exerts a relatively large force on the insertion portion 220 and the first flange portion 230, by setting the weak area 211 on the insertion portion 220 or the first flange portion 230, the weak area 211 can be made more sensitive to the pressure inside the outer casing 100 and more easily achieve the explosion-proof effect.

[0138] According to some embodiments of this application, optionally, such as Figures 6 to 8 As shown, the electrode terminal 200 is provided with a groove 210, and the weak area 211 forms the bottom of the groove 210. The groove 210 is provided on the side surface of the first flange portion 230 facing and / or away from the wall portion 101.

[0139] The side surface of the first flange portion 230 facing the wall portion 101 and the side surface of the first flange portion 230 away from the wall portion 101 may be distributed axially at intervals. The scoring groove 210 may be provided on the side surface of the first flange portion 230 facing the wall portion 101, on the side surface of the first flange portion 230 away from the wall portion 101, or simultaneously on both sides. The weak area 211 may be formed by the scoring groove 210.

[0140] This design facilitates the machining of the groove 210. Furthermore, since the first flange portion 230 is generally thinner in the aforementioned axial direction, the groove 210 is more sensitive to the internal pressure of the housing 100, making it more effective at preventing explosions. When the internal pressure of the housing 100 exceeds a pressure threshold or the temperature exceeds a temperature threshold, the first flange portion 230 can break or bend along the groove 210 in the axial direction, thus achieving the explosion-proof function of the groove 210.

[0141] Furthermore, in the radial direction, the first flange portion 230 and the insertion portion 220 partially overlap and connect, and the scoring groove 210 can be set in the part where the first flange portion 230 and the insertion portion 220 do not overlap, which is beneficial to realize the anti-cracking function of the scoring groove 210.

[0142] According to some embodiments of this application, optionally, such as Figure 6 As shown, the groove 210 is at least partially opposite to the matching slot 240 between the outer peripheral surface of the insertion part 220 and the wall of the lead-out hole 102 along the axial direction.

[0143] By setting the groove 210 at least partially opposite the matching seam 240 along the axial direction, when the electrode terminal 200 breaks or bends along the groove 210, it will not be blocked by the wall 101, making it easier to detach from the lead-out hole 102, which can quickly relieve pressure and more easily achieve the explosion-proof effect.

[0144] Furthermore, the battery cell 1 includes an insulating element 600, which fills the mating gap 240 and provides insulation and sealing. When the pressure inside the housing 100 exceeds a pressure threshold or the temperature exceeds a temperature threshold, the electrode terminal 200 may break or bend along the groove 210, causing the insulating element 600 to loosen its filling of the mating gap 240, thereby allowing gas to escape from the mating gap 240.

[0145] According to some embodiments of this application, optionally, such as Figure 6 As shown, in the radial direction, the radial width D2 of the matching seam 240 is greater than the radial width D1 of the notch groove 210.

[0146] By setting the radial width D2 of the matching slot 240 to be greater than the radial width D1 of the groove 210, the electrode terminal 200 is more likely to be dislodged from the lead-out hole 102 when it breaks or bends along the groove 210, which can quickly relieve pressure and more easily achieve the explosion-proof effect.

[0147] Specifically, when the pressure inside the outer casing 100 exceeds a pressure threshold or the temperature exceeds a temperature threshold, the first flange portion 230 can be split along the groove 210 in the axial direction to form a connecting groove penetrating the first flange portion 230. After the connecting groove is formed, the gas accumulated inside the outer casing 100 can be discharged sequentially through the connecting groove and the matching seam 240.

[0148] According to some embodiments of this application, optionally, such as Figure 6 As shown, the outermost edge of the groove 210 in the radial direction is projected along the axial direction into the matching seam 240.

[0149] In the radial direction, the groove 210 and the matching seam 240 may partially overlap. When the pressure inside the housing 100 exceeds the pressure threshold or the temperature exceeds the temperature threshold, the first flange 230 will be subjected to pressure. The pressure will act on the housing 100 in a direction away from the inside of the housing 100, and the bottom of the groove 210 may deform away from the inside of the housing 100 until the first flange 230 breaks or bends along the groove 210.

[0150] By setting the outermost edge of the groove 210 in the radial direction to be projected into the matching seam 240, the wall portion 101 can be avoided by the matching seam 240 when the bottom of the groove 210 deforms. When the electrode terminal 200 breaks or bends along the groove 210, it is easier to detach from the lead-out hole 102, which can quickly release pressure and is more effective in preventing explosions.

[0151] Furthermore, the projection of the innermost edge of the radial groove 210 along the axial direction can fall within or outside the matching seam 240.

[0152] According to some embodiments of this application, optionally, the radial width D1 of the groove 210 is greater than or equal to 0.5 mm and less than or equal to 2 mm in the radial direction. For example, the radial width D1 of the groove 210 can be set to 0.6 mm, 0.8 mm, 1.0 mm, 1.4 mm, 1.6 mm, etc.

[0153] In the radial direction, by setting the radial width D1 of the groove 210 to be greater than or equal to 0.5 mm, it is beneficial to promote the first flange portion 230 to break or bend along the groove 210 when the internal pressure or temperature of the housing 100 exceeds the pressure threshold or temperature threshold. By setting the radial width D1 of the groove 210 to be less than or equal to 2 mm, the first flange portion 230 can maintain sufficient structural strength, thereby improving the structural stability of the battery cell 1.

[0154] According to some embodiments of this application, optionally, in the axial direction, the axial depth H1 of the groove 210 is greater than or equal to 0.1 times and less than or equal to 0.9 times the axial thickness H0 of the first flange portion 230. For example, the axial depth H1 of the groove 210 can be equal to 0.1 times, 0.2 times, 0.3 times, 0.5 times, or 0.7 times the axial thickness H0 of the first flange portion 230. As another example, when the axial thickness H0 of the first flange portion 230 is equal to 1 mm, the radial width D1 of the groove 210 can be set to 0.2 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, etc.

[0155] In the axial direction, by setting the axial depth H1 of the groove 210 to 0.1 times the axial thickness H0 of the first flange 230, it is beneficial to promote the first flange 230 to break or bend along the groove 210 when the internal pressure or temperature of the housing 100 exceeds the pressure threshold or temperature threshold. By setting the axial depth H1 of the groove 210 to be less than or equal to 0.9 times the axial thickness H0 of the first flange 230, the first flange 230 can maintain sufficient structural strength, which is beneficial to improving the structural stability of the battery cell 1.

[0156] According to some embodiments of this application, optionally, such as Figure 9 As shown, the weak area 211 is at least partially located on the outer peripheral surface of the insertion part 220.

[0157] This design facilitates the processing of the weak area 211 and makes it easier for the insertion part 220 to break along the weak area 211.

[0158] When the internal pressure of the casing 100 exceeds the pressure threshold or the temperature exceeds the temperature threshold, the insertion part 220 may break or bend from the outer peripheral surface along the weak area 211, which can reduce the risk of the battery cell 1 exploding.

[0159] For example, the weak area 211 can be formed at the bottom of the groove 210, the groove opening of the groove 210 can be opened on the outer peripheral surface of the insertion part 220, and the weak area 211 can be located in the first flange part 230. When the internal pressure of the housing 100 exceeds the pressure threshold or the temperature exceeds the temperature threshold, the insertion part 220 and the weak area 211 can break or bend simultaneously along the groove 210.

[0160] According to some embodiments of this application, optionally, such as Figure 10As shown, the electrode terminal 200 includes an insertion portion 220 and a sealing portion 250 connected to each other. The insertion portion 220 is inserted into the lead-out hole 102 along the axial direction of the electrode terminal 200. The insertion portion 220 is cylindrical. The sealing portion 250 seals the end of the insertion portion 220 facing the inside of the housing 100 to form a recess 260. A weak area 211 is provided on the sealing portion 250.

[0161] The recess 260 may be formed on the side of the sealing portion 250 away from the interior of the outer casing 100. When the weak area 211 is provided on the side surface of the sealing portion 250 facing the recess 260, it may communicate with the recess 260.

[0162] The weak area 211 is provided on the side surface of the sealing part 250 facing the recessed part 260, or it can be provided on the side surface of the sealing part 250 away from the recessed part 260, or it can be provided on both the side surface of the sealing part 250 facing the recessed part 260 and the side surface of the sealing part 250 away from the recessed part 260.

[0163] The side surface of the sealing portion 250 facing the recess 260 and the side surface of the sealing portion 250 away from the recess 260 may be distributed axially at intervals. By providing the weak area 211 on the side surface of the sealing portion 250 facing and / or away from the recess 260, when the pressure inside the housing 100 exceeds the pressure threshold or the temperature exceeds the temperature threshold, the sealing portion 250 may break or bend along the weak area 211 to allow gas inside the housing 100 to enter the recess 260 and be discharged through the recess 260.

[0164] By providing the recessed portion 260, the thickness of the sealing portion 250 in the axial direction can be less than the thickness of the insertion portion 220. Since the sealing portion 250 is relatively thin in the aforementioned axial direction, the weak area 211 is more sensitive to the internal pressure of the outer casing 100, and is more likely to achieve an explosion-proof effect.

[0165] According to some embodiments of this application, optionally, such as Figure 10 As shown, the sealing part 250 is welded to the insertion part 220 to form a weld mark 700, and the weak area 211 is located within the weld mark 700.

[0166] By controlling the welding process, the weld mark 700 can be used as a weak area 211. When the pressure inside the casing 100 exceeds the pressure threshold or the temperature exceeds the temperature threshold, the weak area 211 can be destroyed. This setting simplifies the manufacturing process of the battery cell 1.

[0167] In some embodiments, the battery cell 1 further includes a current collector 400 disposed inside the housing 100. After the sealing portion 250 is welded to the current collector 400, a solder mark 700 is formed, and the sealing portion 250 and the current collector 400 are electrically connected through the solder mark 700. If the pressure inside the housing 100 exceeds a pressure threshold or the temperature exceeds a temperature threshold, the sealing portion 250 may break along the weak area 211, thereby blocking the current path between the electrode terminal 200 and the electrode assembly 500, and delaying the release of electrical energy.

[0168] In other embodiments, a weak region 211 is provided on the sealing portion 250 and surrounds the solder mark 700. This arrangement allows the sealing portion 250 to break along the weak region 211 when the internal pressure of the housing 100 exceeds a pressure threshold or the temperature exceeds a temperature threshold, thereby blocking the current path between the electrode terminal 200 and the electrode assembly 500 and delaying the release of electrical energy.

[0169] According to some embodiments of this application, optionally, such as Figure 5 As shown, the weak zone 211 is arranged in a ring around the central axis of the lead-out hole 102.

[0170] This design makes the weak point 211 more sensitive to the internal pressure of the housing 100, thus providing better explosion protection. Specifically, if the internal pressure of the housing 100 exceeds a pressure threshold or the temperature exceeds a temperature threshold, the electrode terminal 200 may break along the weak point 211. Radially, the portion of the electrode terminal 200 located inside the weak point 211 may separate from the portion located outside the weak point 211. Alternatively, the portion of the electrode terminal 200 located inside the weak point 211 may bend away from the interior of the housing 100.

[0171] According to some embodiments of this application, optionally, such as Figure 3 and Figure 6 As shown, the electrode terminal 200 includes an insertion portion 220 and a sealing portion 250 connected to each other. The insertion portion 220 is inserted into the lead-out hole 102 along the axial direction of the electrode terminal 200 and is cylindrical in shape. The sealing portion 250 seals the end of the insertion portion 220 facing the inside of the housing 100 to form a recess 260. The battery cell 1 includes a sealing member 300 for sealing the recess 260. The battery cell 1 is electrically connected to the outside through the sealing member 300.

[0172] By providing a sealing component 300 to seal the recess 260, the sealing component 300 can be used to increase the connection area between the battery cell 1 and external devices, and alleviate electrolyte leakage inside the battery cell 1.

[0173] Specifically, by fixing the sealing element 300 to the electrode terminal 200, a current path can be formed between the electrode assembly 500, the electrode terminal 200, and the sealing element 300. The electrode assembly 500 can be electrically connected to the outside via the electrode terminal 200 and the sealing element 300 in sequence. For example, a battery cell 1 can be connected to a busbar via the sealing element 300. A busbar is a multi-layered composite structure connecting bar that can connect multiple battery cells 1 in series or parallel by welding or bolting.

[0174] Furthermore, a second flange 270 may be formed at the end of the electrode terminal 200 facing away from the interior of the housing 100. The opening of the recess 260 is located in the second flange 270. The sealing member 300 may be connected to the second flange 270 to seal the recess 260. The electrode terminal 200 may be electrically connected to the outside through the sealing member 300. The wall portion 101 may be confined between the first flange 230 and the second flange 270 to restrict the relative movement between the electrode terminal 200 and the housing 100.

[0175] According to some embodiments of this application, optionally, such as Figure 3 As shown, the recess 260 is used to inject electrolyte into the interior of the housing 100.

[0176] During the production of battery cell 1, the recess 260 can connect to the interior of the outer casing 100, thereby allowing electrolyte to be injected into the interior of the outer casing 100 through the recess 260. By providing the recess 260, electrolyte can be injected through the recess 260 after the electrode terminals 200 are assembled and connected to the outer casing 100, and then sealed by the sealing member 300. This simplifies the structural complexity of battery cell 1, reduces the occurrence of electrolyte leakage during assembly, and improves the assembly efficiency of battery cell 1.

[0177] According to some embodiments of this application, optionally, such as Figure 3 As shown, the sealing part 250 is provided with an injection hole 251, which connects the interior of the outer shell 100 with the recessed part 260.

[0178] During the assembly of battery cell 1, when electrolyte is injected, the electrolyte can sequentially pass through the recess 260 and the injection hole 251 before entering the interior of the housing 100. The injection hole 251 facilitates sealing after electrolyte injection, reducing the risk of electrolyte leakage. The sealing portion 250 is thinner than the insertion portion 220; by placing the injection hole 251 within the sealing portion 250, the formation of the injection hole 251 is facilitated, and electrolyte injection is convenient.

[0179] Optionally, the two ends of the injection hole 251 along the axial direction can be connected to the recess 260 and the interior of the outer casing 100, respectively.

[0180] When the sealing portion 250 has a weak area 211, in order to realize the function of the weak area 211, the sealing of the injection hole 251 is configured to not be damaged by pressure within the pressure threshold range or temperature within the temperature threshold range inside the housing 100. Of course, in some embodiments, the electrode terminal 200 may not have an injection hole 251.

[0181] According to some embodiments of this application, optionally, such as Figure 3 As shown, the battery cell 1 also includes a current collector 400 and an electrode assembly 500 disposed inside the housing 100. The current collector 400 is used to connect the tabs 501 and the electrode terminals 200 of the electrode assembly 500. The sealing portion 250 is welded to the current collector 400 on the side opposite to the recessed portion 260.

[0182] The current collector 400 can be disposed between the electrode terminal 200 and the electrode assembly 500, and serves to form a current path between the electrode terminal 200 and the electrode assembly 500. By providing the current collector 400, electrical connection between the electrode terminal 200 and the electrode assembly 500 is easily achieved. Taking advantage of the thinness of the sealing part 250, it is welded to the current collector 400, facilitating electrical connection between the electrode terminal 200 and the current collector 400 from the side of the electrode terminal 200 away from the current collector 400.

[0183] According to some embodiments of this application, optionally, such as Figure 3 As shown, the battery cell 1 includes an electrode assembly 500, and the housing 100 includes a housing 110 and an end cap 120. One end of the housing 110 has an opening 111, and the end cap 120 covers the opening 111. The housing 110 includes a side wall 112 and an end wall 113. The side wall 112 surrounds the outside of the electrode assembly 500, and the end wall 113 is disposed opposite to the opening 111. The wall portion 101 is either the end cap 120 or the end wall 113.

[0184] In the above embodiment, the wall portion 101 is an end wall 113. In other embodiments, the wall portion 101 may also be an end cap 120.

[0185] Since the end cap 120 or end wall 113 is flatter than the side wall 112, the assembly efficiency of the battery cell 1 can be improved by setting the electrode terminal 200 on the end cap 120 or end wall 113.

[0186] The electrode assembly 500 can be supported inside the housing 100 by the end cap 120 or the end wall 113. If the weak area 211 is located in the end cap 120 or the end wall 113, it will weaken the structural strength of the end cap 120 or the end wall 113, reduce the load-bearing capacity of the end cap 120 or the end wall 113, and make the end cap 120 or the end wall 113 prone to deformation under stress, which is not conducive to the assembly process of the battery cell 1. Therefore, by setting the weak area 211 in the electrode terminal 200, the possibility of deformation of the end cap 120 or the end wall 113 can be reduced, which facilitates the assembly of the battery cell 1.

[0187] According to some embodiments of this application, optionally, the melting point of the material of the electrode terminal 200 is lower than the melting point of the material of the housing 100.

[0188] When welding the electrode terminal 200 to other components, the lower melting point of the electrode terminal 200 material helps to reduce the welding temperature, while the relatively higher melting point of the housing 100 material can reduce the adverse effects of the welding process on the housing 100, thereby reducing the risk of leakage.

[0189] According to some embodiments of this application, optionally, the difference between the melting point of the material of the outer shell 100 and the melting point of the material of the electrode terminal 200 is greater than 300°C.

[0190] This configuration helps to reduce the welding temperature when welding the electrode terminal 200 to other components, and also reduces the damage to the housing 100 during the welding process, thereby reducing the risk of leakage.

[0191] According to some embodiments of this application, optionally, the material of the housing 100 includes steel, and the material of the electrode terminal 200 includes aluminum or copper.

[0192] By making the outer casing 100 of steel, the outer casing 100 can have a lower coefficient of thermal expansion and good mechanical strength. Copper or aluminum has a lower melting point than steel, and making the electrode terminals 200 of copper or aluminum can make the electrode terminals 200 easier to weld, while copper or aluminum is easier to process and shape.

[0193] According to some embodiments of this application, optionally, such as Figures 3 to 10As shown, the battery cell 1 includes a housing 100 and electrode terminals 200. The housing 100 includes a wall portion 101, and the wall portion 101 is provided with a lead-out hole 102. The electrode terminals 200 are disposed in the lead-out hole 102, and the electrode terminals 200 are provided with a weak area 211. The weak area 211 is configured to be damaged when the internal pressure of the housing 100 exceeds a pressure threshold or the temperature exceeds a threshold, so that the interior of the housing 100 communicates with the exterior of the housing 100. The electrode terminals 200 are provided with a groove 210, and the weak area 211 forms the bottom of the groove 210. Electrode terminal 200 includes an insertion portion 220 and a first flange portion 230 connected to each other. The insertion portion 220 is inserted into a lead-out hole 102 along the axial direction of the electrode terminal 200. In the radial direction of the electrode terminal 200, the outer peripheral surface of the first flange portion 230 at least partially extends beyond the outer peripheral surface of the insertion portion 220. The portion of the first flange portion 230 located on the periphery of the lead-out hole 102 is supported on the side of the wall portion 101 facing the interior of the housing 100. A weak region 211 is provided on the insertion portion 220 and / or the first flange portion 230. Electrode terminal 200 is provided with a scoring groove 210, and the weak region 211 forms the bottom of the scoring groove 210. The scoring groove 210 is provided on the side surface of the first flange portion 230 facing and / or away from the wall portion 101. The scoring groove 210 is at least partially opposite to the matching slot 240 between the outer peripheral surface of the insertion portion 220 and the wall of the lead-out hole 102 along the axial direction. In the radial direction, the radial width D2 of the mating slot 240 is greater than the radial width D1 of the scoring groove 210. The axial projection of the outermost edge of the scoring groove 210 in the radial direction falls within the mating slot 240. In the radial direction, the radial width D1 of the scoring groove 210 is greater than or equal to 0.5 mm and less than or equal to 2 mm. In the axial direction, the axial depth H1 of the scoring groove 210 is greater than or equal to 0.1 times the axial thickness H0 of the first flange portion 230 and less than or equal to 0.9 times the axial thickness H0 of the first flange portion 230. The weak area 211 is at least partially located on the outer peripheral surface of the insertion portion 220. The electrode terminal 200 includes an insertion portion 220 and a sealing portion 250 connected to each other. The insertion portion 220 is inserted into the lead-out hole 102 along the axial direction of the electrode terminal 200 and is cylindrical in shape. The sealing portion 250 seals the end of the insertion portion 220 facing the interior of the housing 100 to form a recess 260. A weak area 211 is provided on the sealing portion 250. The sealing portion 250 is welded to the insertion portion 220 to form a solder mark 700, and the weak area 211 is located within the solder mark 700. The weak area 211 is arranged in a ring around the central axis of the lead-out hole 102.The electrode terminal 200 includes an insertion portion 220 and a sealing portion 250 connected to each other. The insertion portion 220 is inserted into the lead-out hole 102 along the axial direction of the electrode terminal 200 and is cylindrical in shape. The sealing portion 250 seals the end of the insertion portion 220 facing the inside of the outer casing 100 to form a recess 260. The battery cell 1 includes a sealing member 300 for sealing the recess 260, and the battery cell 1 is electrically connected to the outside through the sealing member 300. The recess 260 is used to inject electrolyte into the interior of the outer casing 100. The sealing portion 250 is provided with an injection hole 251, which communicates the interior of the outer casing 100 with the recess 260. The battery cell 1 also includes a current collector 400 and an electrode assembly 500 disposed inside the housing 100. The current collector 400 is used to connect the tabs 501 and electrode terminals 200 of the electrode assembly 500. The sealing portion 250 is welded to the current collector 400 on the side opposite to the recessed portion 260. The battery cell 1 includes the electrode assembly 500, and the housing 100 includes a shell 110 and an end cap 120. One end of the shell 110 has an opening 111, and the end cap 120 covers the opening 111. The shell 110 includes a side wall 112 and an end wall 113. The side wall 112 surrounds the outside of the electrode assembly 500, and the end wall 113 is disposed opposite to the opening 111. The wall portion 101 is either the end cap 120 or the end wall 113. The melting point of the material of the electrode terminal 200 is lower than the melting point of the material of the housing 100. The difference between the melting point of the material of the housing 100 and the melting point of the material of the electrode terminal 200 is greater than 300°C. The outer casing 100 is made of steel, and the electrode terminals 200 are made of aluminum or copper.

[0194] According to some embodiments of this application, such as Figure 2 As shown, battery 100a includes the aforementioned battery cell 1. This configuration improves the stability and reliability of battery cell 1 during operation by reducing the risk of casing 100 rupture, thereby improving the stability and reliability of battery 100a during operation.

[0195] According to some embodiments of this application, such as Figure 1 As shown, the electrical device includes the aforementioned battery 100a. This configuration improves the stability and reliability of the battery 100a during operation by enhancing the stability and reliability of the individual battery cells 1, thereby improving the stability and reliability of the electrical device itself.

[0196] In summary, the embodiments of this application can achieve the following: when the pressure exceeds the pressure threshold or the temperature exceeds the temperature threshold, the electrode terminal 200 can break or bend along the weak area 211 under the action of pressure, so that the inside of the outer casing 100 is connected to the outside of the outer casing 100, and the excess gas inside the outer casing 100 can be discharged, reducing the risk of the battery cell 1 exploding due to excessive internal pressure, and at the same time reducing the possibility of deformation of the outer casing 100, which facilitates the assembly of the battery cell 1.

[0197] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, The battery cell includes: The housing includes a wall portion, the wall portion being provided with an outlet hole; An electrode terminal is provided at the lead-out hole. The electrode terminal is provided with a weak area, which is configured to be broken when the internal pressure or temperature of the housing exceeds a pressure threshold, so that the interior of the housing is connected to the exterior of the housing.

2. The battery cell according to claim 1, characterized in that, The electrode terminal is provided with a groove, and the weak area forms the bottom of the groove.

3. The battery cell according to claim 1, characterized in that, The electrode terminal includes an insertion portion and a first flange portion connected to each other. The insertion portion is inserted into the lead-out hole along the axial direction of the electrode terminal. In the radial direction of the electrode terminal, the outer peripheral surface of the first flange portion at least partially extends beyond the outer peripheral surface of the insertion portion. The portion of the first flange portion located around the lead-out hole is supported on the side of the wall portion facing the interior of the housing. The weak area is located on the insertion portion and / or the first flange portion.

4. The battery cell according to claim 3, characterized in that, The electrode terminal is provided with a groove, and the weak area forms the bottom of the groove. The groove is provided on the side surface of the first flange facing and / or away from the wall.

5. The battery cell according to claim 4, characterized in that, The groove is at least partially opposite to the matching seam between the outer peripheral surface of the insertion part and the wall of the lead-out hole along the axial direction.

6. The battery cell according to claim 5, characterized in that, In the radial direction, the radial width of the matching seam is greater than the radial width of the scoring groove.

7. The battery cell according to claim 6, characterized in that, The projection of the outermost edge of the groove in the radial direction along the axial direction falls within the matching seam.

8. The battery cell according to claim 7, characterized in that, In the radial direction, the radial width of the groove is greater than or equal to 0.5 mm and less than or equal to 2 mm.

9. The battery cell according to claim 8, characterized in that, In the axial direction, the axial depth of the groove is greater than or equal to 0.1 times the axial thickness of the first flange and less than or equal to 0.9 times the axial thickness of the first flange.

10. The battery cell according to claim 3, characterized in that, The weak area is at least partially located on the outer peripheral surface of the insertion part.

11. The battery cell according to claim 1, characterized in that, The electrode terminal includes an insertion part and a sealing part connected to each other. The insertion part is inserted into the lead-out hole along the axial direction of the electrode terminal. The insertion part is cylindrical. The sealing part seals the end of the insertion part facing the inside of the housing to form a recess. The weak area is provided on the sealing part.

12. The battery cell according to claim 11, characterized in that, The sealing part is welded to the insertion part to form a weld mark, and the weak area is located within the weld mark.

13. The battery cell according to claim 1, characterized in that, The weak zone is arranged in a ring around the central axis of the outlet hole.

14. The battery cell according to claim 1, characterized in that, The electrode terminal includes an insertion part and a sealing part connected to each other. The insertion part is inserted into the lead-out hole along the axial direction of the electrode terminal. The insertion part is cylindrical. The sealing part seals the end of the insertion part facing the inside of the housing to form a recess. The battery cell includes a sealing member for sealing the recess. The battery cell is electrically connected to the outside through the sealing member.

15. The battery cell according to claim 14, characterized in that, The recessed portion is used to inject electrolyte into the interior of the outer casing.

16. The battery cell according to claim 15, characterized in that, The sealing part is provided with a liquid injection hole, which connects the interior of the outer shell with the recessed part.

17. The battery cell according to claim 14, characterized in that, The battery cell also includes a current collector and an electrode assembly disposed inside the housing. The current collector is used to connect the tabs of the electrode assembly and the electrode terminals. The side of the sealing portion opposite to the recessed portion is welded to the current collector.

18. The battery cell according to any one of claims 1-17, characterized in that, The battery cell includes an electrode assembly, the housing includes a shell and an end cap, one end of the shell has an opening, the end cap covers the opening, the shell includes a side wall and an end wall, the side wall surrounds the outside of the electrode assembly, the end wall is disposed opposite to the opening, and the wall portion is the end cap or the end wall.

19. The battery cell according to claim 1, characterized in that, The melting point of the electrode terminal material is lower than that of the outer shell material.

20. The battery cell according to claim 19, characterized in that, The difference between the melting point of the outer shell material and the melting point of the electrode terminal material is greater than 300°C.

21. The battery cell according to claim 1, characterized in that, The outer casing is made of steel, and the electrode terminals are made of aluminum or copper.

22. A battery, characterized in that, Includes the battery cell as described in any one of claims 1-21.

23. An electrical appliance, characterized in that, The electrical device includes the battery as described in claim 22.

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