Battery cell, battery, and electric device

Abstract

A battery cell (30), a battery (10), and an electric device. The battery cell (30) comprises a casing (31) and a pressure relief mechanism (40); the casing (31) comprises an accommodating cavity (30a) and a first wall (313); the pressure relief mechanism (40) is arranged on the first wall (313) and comprises a body portion (41) and an insulating portion (42), the material of the body portion (41) comprises a metal material, the insulating portion (42) is arranged on the side of the body portion facing away from the accommodating cavity (30a), and the melting point T1 of the insulating portion (42) satisfies: T1≥400°C. In the event of thermal runaway of the battery cell (30), the insulating portion (42) flips over, and the pressure relief mechanism (40) overlaps a conductive supporting member (50) inside the battery (10) by means of the insulating portion (42), reducing the risk of short circuit inside the battery (10), and thus improving the reliability of the battery (10).

Description

Battery cells, batteries and electrical devices

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese patent application CN202420831009.6, filed on April 22, 2024, entitled “Battery cell, battery and electrical device”, the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] Batteries are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0005] In the development of battery technology, in addition to improving battery performance, reliability is also a crucial consideration. Therefore, improving battery reliability is a continuous challenge in battery technology development.

[0006] Summary of the Invention

[0007] This application provides a battery cell, a battery, and an electrical device to improve the reliability of the battery.

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

[0009] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a casing and a pressure relief mechanism; the casing includes a receiving cavity and a first wall; the pressure relief mechanism is disposed on the first wall, the pressure relief mechanism includes a body part and an insulating part, the material of the body part includes a metallic material, the insulating part is disposed on the side of the body part away from the receiving cavity, and the melting point T1 of the insulating part satisfies: T1≥400℃.

[0010] According to the embodiments of this application, the battery cell includes a pressure relief mechanism comprising a body and an insulating part, with the insulating part located on the side of the body facing away from the receiving cavity. The melting point T1 of the insulating part satisfies: T1≥400℃. In the event of thermal runaway of the battery cell, the pressure relief mechanism opens, and the insulating part does not melt and flips with the body. The pressure relief mechanism connects with a conductive support inside the battery through the insulating part, which helps to reduce the risk of internal short circuits in the battery and thus improves the reliability of the battery.

[0011] According to some embodiments of this application, the insulating portion covers the body portion.

[0012] In the above scheme, when the pressure relief mechanism is flipped, it is further beneficial to reduce the risk of internal short circuit of the battery caused by contact between the main body and the guide, which is beneficial to further improve the reliability of the battery.

[0013] According to some embodiments of this application, the insulating part has a through hole, and the insulating part is disposed around the periphery of the through hole.

[0014] In the above scheme, when the pressure relief mechanism is flipped, the insulation part comes into contact with the support, which reduces the risk of internal short circuit in the battery, and also helps to reduce the weight and amount of insulation part, thus reducing the weight and production cost of the battery cell.

[0015] According to some embodiments of this application, the insulating portion covers the outer edge of the body portion.

[0016] In the above scheme, the insulating part is set to cover the outer edge of the main body. When the pressure relief mechanism releases pressure, after the pressure relief mechanism flips outward, the insulating part will preferentially contact the conductive support. This is beneficial to further improve the insulation effect of the insulating part on the main body and the conductive support outside the battery cell while reducing the weight and amount of the insulating part, and further reduce the risk of internal short circuit of the battery.

[0017] According to some embodiments of this application, the body portion is sheet-like, and / or the insulating portion is sheet-like.

[0018] In the above scheme, the body and / or insulation occupy little space, which is convenient for processing and manufacturing. Furthermore, the thickness of the body or insulation can be reasonably set according to the pressure relief threshold of the pressure relief mechanism to improve the timeliness and accuracy of the pressure relief mechanism opening.

[0019] According to some embodiments of this application, the insulating material is one of polyimide, ceramic, and mica.

[0020] In the above solutions, polyimide, ceramics, and mica can all meet the melting point requirements of the insulation part, and are relatively inexpensive and readily available. In the event of thermal runaway of the battery cell, the insulation part can meet the insulation requirements of the body and the conductive support component, and helps to reduce the production cost of the battery cell.

[0021] According to some embodiments of this application, the pressure relief mechanism further includes a reinforcing part disposed between the body part and the insulating part.

[0022] In the above scheme, the reinforcement can improve the overall structural strength of the pressure relief mechanism, reduce the risk of the pressure relief mechanism being mistakenly opened due to vibration or impact loads during normal operation of the battery cell, and help improve the reliability of the battery cell.

[0023] According to some embodiments of this application, the reinforcing part includes a coating applied to the surface of the body part facing the insulating part, and the melting point T2 of the coating satisfies: T2 < 400°C.

[0024] In the above scheme, the reinforcing part includes a coating, which facilitates the processing and manufacturing of the reinforcing part. The melting point of the coating is set to T2 < 400℃, so that the coating can melt in time in the event of thermal runaway of the battery cell, so that the pressure relief mechanism can be opened in time.

[0025] According to some embodiments of this application, the pressure relief mechanism further includes an insulating thermal expansion portion, which is disposed between the insulating portion and the body portion, and is configured to expand and deform when heated.

[0026] In the above scheme, setting an insulating thermal expansion section between the body and the insulating section is beneficial to reducing the volume occupied by the pressure relief mechanism and increasing the energy density of the battery cell. It is also beneficial to increase the creepage distance between the body and the conductive support of the battery in the event of thermal runaway of the battery cell, which further improves the reliability of the battery.

[0027] According to some embodiments of this application, the material of the insulating thermal expansion portion is thermally expandable graphite.

[0028] In the above scheme, thermally expandable graphite is inexpensive and has good insulation properties and high temperature resistance. In addition, thermally expandable graphite has a high coefficient of thermal expansion. In the event of thermal runaway in a battery cell, the pressure relief mechanism opens, and the thermally expandable insulating part expands to have a higher thickness. This is beneficial to further improve the insulation distance and insulation performance between the main body and the conductive support, thereby improving the reliability of the battery.

[0029] Secondly, embodiments of this application provide a battery including a support member and a battery cell provided in any of the above embodiments. The support member is disposed on one side of the first wall of the battery cell. The material of the support member includes a metal material. The support member has a through hole, which is disposed opposite to the pressure relief mechanism.

[0030] The battery provided in this application embodiment includes a pressure relief mechanism for each battery cell comprising a body and an insulating part. The insulating part is located on the side of the body facing away from the receiving cavity. The melting point of the insulating part, T1, is ≥400°C. In the event of thermal runaway of the battery cell, the pressure relief mechanism opens without melting the insulating part, which then flips over with the body. The pressure relief mechanism connects with the support member through the insulating part, which helps to reduce the risk of internal short circuits in the battery and thus improves the reliability of the battery.

[0031] According to some embodiments of this application, the insulating part is in the form of a sheet, and the ratio of the thickness e of the insulating part to the maximum voltage U of the battery is greater than or equal to 0.0005 and less than or equal to 0.02, where e is in millimeters and U is in volts.

[0032] In the above scheme, the ratio of the thickness e of the insulation part to the maximum voltage U of the battery is greater than or equal to 0.0005 and less than or equal to 0.02. In the case of thermal runaway of the battery cell, this is beneficial to reduce the risk of insulation failure caused by the insulation part being broken down, to improve the insulation performance of the insulation part, to reduce the volume of the battery cell occupied by the insulation part, and to improve the energy density of the battery cell.

[0033] According to some embodiments of this application, the insulating part is sheet-like, and the ratio of the product of the thickness e of the insulating part and the creepage distance c of the battery and the breakdown field strength E of the insulating part is greater than or equal to 0.00015, where e and c are in millimeters and E is in kilovolts per meter.

[0034] In the above scheme, in the event of thermal runaway in a single battery cell, it helps to reduce the risk of insulation failure caused by the breakdown of the insulation part.

[0035] According to some embodiments of this application, the insulating part has a through hole, and the insulating part is disposed around the periphery of the through hole; the orthographic projection of the insulating part on the first wall is a first projection, the first projection is annular, the first projection has a first edge and a second edge, the second edge is located inside the first edge, and the ratio of the minimum distance d between the first edge and the second edge to the maximum voltage U of the battery is greater than or equal to 0.0005, where the unit of d is millimeters and the unit of U is volts.

[0036] In the above scheme, setting the ratio of the minimum distance d between the first edge and the second edge to the maximum voltage U of the battery to be greater than or equal to 0.0005 is beneficial to reduce the weight of the insulation part and, in the event of thermal runaway of the battery cell, to reduce the risk of insulation failure due to the breakdown of the insulation part.

[0037] Thirdly, the electrical device provided in the embodiments of this application includes the battery or battery cell provided in any of the above embodiments, and the battery is used to provide electrical energy.

[0038] The electrical device provided in this application embodiment has the same technical effect because it uses the battery or battery cell provided in this application embodiment, and will not be described again here.

[0039] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0041] Figure 1 is a structural schematic diagram of the vehicle provided in an embodiment of this application;

[0042] Figure 2 is a schematic diagram of the battery structure provided in an embodiment of this application;

[0043] Figure 3 is a schematic diagram of the structure of the battery module in the battery provided in the embodiment of this application;

[0044] Figure 4 is a schematic diagram of the exploded structure of a single battery cell provided in an embodiment of this application;

[0045] Figure 5 is a cross-sectional view of the battery provided in an embodiment of this application;

[0046] Figure 6 is an exploded view of a pressure relief mechanism for a battery cell provided in an embodiment of this application;

[0047] Figure 7 is an exploded view of another pressure relief mechanism for a battery cell provided in an embodiment of this application;

[0048] Figure 8 is an exploded view of another pressure relief mechanism for a battery cell provided in an embodiment of this application;

[0049] Figure 9 is an exploded view of another pressure relief mechanism for a battery cell provided in an embodiment of this application;

[0050] Figure 10 is a front view of the pressure relief mechanism in a battery cell provided in an embodiment of this application;

[0051] Figure 11 is a schematic diagram of the first projection of the insulating part of the pressure relief mechanism in the battery cell provided in the embodiment of this application.

[0052] The accompanying drawings are not necessarily drawn to scale.

[0053] Explanation of reference numerals in the attached figures:

[0054] 1-Vehicle; 1a-Motor; 1b-Controller;

[0055] 10-Battery; 11-Box; 11a-Exhaust channel; 111-First sub-box; 112-Second sub-box;

[0056] 20-Battery Module;

[0057] 30-Battery cell; 31-Casing; 30a-Receiving cavity; 311-Housing shell; 312-End cap; 313-First wall; 32-Electrode assembly;

[0058] 40 - Pressure relief mechanism; 41 - Body part; 42 - Insulation part; 42a - Through hole; 43 - Reinforcing part; 431 - First projection; 431a - First edge; 431b - Second edge; 44 - Insulating thermal expansion part;

[0059] 50 - Support component; 50a - Through hole. Detailed Implementation

[0060] 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 and completely 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.

[0061] 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.

[0062] In this application, the reference to "embodiment" means that a specific 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 mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0063] 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.

[0064] 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.

[0065] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0066] 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.

[0067] 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.

[0068] 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.

[0069] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0070] 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.

[0071] The battery cell may be, but is not limited to, 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.

[0072] 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, prevents short circuits while allowing active ions to pass through.

[0073] 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.

[0074] 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.

[0075] 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 made of stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium with a silver-plated surface. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector 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.).

[0076] 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.

[0077] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0078] As an example, the negative 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, or made of carbon, nickel, or titanium, etc.

[0079] In some embodiments, 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.

[0080] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. 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 negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0085] In some implementations, the electrode assembly is a stacked structure.

[0086] 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.

[0087] In some embodiments, the housing includes an end cap and a casing, the casing having an opening, and the end cap closing the opening to form a sealed space for accommodating substances such as electrode assemblies and electrolytes. The casing may have one or more openings. The end cap may also be provided one or more times.

[0088] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab of the electrode assembly. The electrode terminal can be directly connected to the tab or indirectly connected to the tab via an adapter. The electrode terminal can be located on the end cap or on the housing.

[0089] In some implementations, an explosion-proof valve is provided on the housing. The explosion-proof valve is used to release the internal pressure of the battery cells.

[0090] As an example, the 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 prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. There are no particular limitations in the embodiments of this application.

[0091] The pressure relief mechanism is an important component of a battery cell. When the pressure inside the battery cell reaches a predetermined threshold, the pressure relief mechanism opens, allowing the gas inside the battery cell to escape. This helps reduce the risk of the battery cell exploding due to a further increase in internal pressure.

[0092] However, in related technologies, after battery cells are assembled into battery cells, the pressure relief mechanism of the battery cell is usually adjacent to the support component. The support component is used to support the battery cell, and its material usually includes metal, which has a certain degree of conductivity. Thus, during the pressure relief process of the battery cell, the pressure relief mechanism flips outward and opens. After the pressure relief mechanism opens, there is a significant risk that it will come into contact with and become electrically connected to the conductive support component inside the battery. Therefore, during the pressure relief process of the battery cell, there is a high risk of internal short circuit, which seriously affects the reliability of the battery.

[0093] In view of this, the battery cell provided in the embodiments of this application includes a casing and a pressure relief mechanism. The casing includes a receiving cavity and a first wall. The pressure relief mechanism is disposed on the first wall and includes a body and an insulating part. The body is made of a metallic material, and the insulating part is disposed on the side of the body facing away from the receiving cavity. The melting point T of the insulating part satisfies: T ≥ ℃.

[0094] The battery cell provided in this application embodiment has an insulating part in the pressure relief mechanism, and the insulating part is located on the side of the main body facing away from the receiving cavity. The melting point T of the insulating part satisfies: T ≥ ℃. In the event of thermal runaway of the battery cell, the pressure relief mechanism flips outward. Since the melting point of the insulating part is higher than the temperature during the pressure relief process of the battery cell, the insulating part remains intact and contacts the conductive support inside the battery. This ensures that the main body is insulated from the support, reducing the risk of internal short circuits in the battery and improving the reliability of the battery.

[0095] The technical solutions provided in this application are applicable to battery cells, batteries including battery cells, and electrical devices that use batteries.

[0096] The batteries disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using batteries disclosed in this application.

[0097] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric bicycles, electric motorcycles, 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. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0098] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0099] Please refer to Figure 1, which is a schematic diagram of the vehicle structure provided in some embodiments of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery 10 is installed inside vehicle 1, and the battery 10 can be located at the bottom, front, or rear of vehicle 1. The battery 10 can be used to power vehicle 1; for example, the battery 10 can serve as the operating power source for vehicle 1's electrical system, such as meeting the power requirements for starting, navigation, and operation of vehicle 1.

[0100] The vehicle 1 may also include a controller 1b and a motor 1a. The controller 1b is used to control the battery 10 to supply power to the motor 1a, for example, for the power needs of the vehicle 1 during startup, navigation and driving.

[0101] In some embodiments of this application, the battery 10 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0102] Please refer to Figures 2 and 3. Figure 2 is a structural schematic diagram of the battery 10 provided in an embodiment of this application, and Figure 3 is a structural schematic diagram of the battery module 20 in the battery 10 provided in an embodiment of this application. The battery 10 includes a housing 11 and a battery cell 30, with the battery cell 30 housed within the housing 11. The housing 11 provides a space for the battery cell 30, and the housing 11 can adopt various structures. In some embodiments, the housing 11 may include a first sub-housing 111 and a second sub-housing 112, which overlap each other, and together define a space for accommodating the battery cell 30. The second sub-box 112 can be a hollow structure with one end open, and the first sub-box 111 can be a plate-like structure. The first sub-box 111 covers the opening side of the second sub-box 112 so that the first sub-box 111 and the second sub-box 112 together define the accommodating space. Alternatively, the first sub-box 111 and the second sub-box 112 can both be hollow structures with one side open, and the opening side of the first sub-box 111 covers the opening side of the second sub-box 112.

[0103] In battery 10, there can be multiple battery cells 30, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 30 are connected in both series and parallel configurations. Multiple battery cells 30 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 30 is housed within the housing 11. Alternatively, battery 10 can also consist of multiple battery cells 30 first connected in series, parallel, or in a mixed manner to form a battery module 20, and then multiple battery modules 20 are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 11. Battery 10 may also include other structures; for example, battery 10 may also include a busbar component for electrical connection between multiple battery cells 30.

[0104] Among them, the battery cell 30 can be a secondary battery or a primary battery; the battery cell 30 can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited to these.

[0105] Please refer to Figure 4, which is an exploded view of a battery cell 30 provided in some embodiments of this application. As shown in Figure 3, the battery cell 30 includes a housing 31, an electrode assembly 32, and electrode terminals. The housing 31 includes a shell 311 and an end cap 312. The shell 311 has an opening, and the end cap 312 closes the opening to isolate the internal environment of the battery cell 30 from the external environment.

[0106] The housing 311 is a component used to cooperate with the end cap 312 to form the internal environment of the battery cell 30, wherein the formed internal environment can accommodate the electrode assembly 32, electrolyte, and other components. The housing 311 and the end cap 312 can be independent components. The housing 311 can have various shapes and sizes. Specifically, the shape of the housing 311 can be determined according to the specific shape and size of the electrode assembly 32. The housing 311 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0107] End cap 312 refers to a component that covers the opening of housing 311 to isolate the internal environment of battery cell 30 from the external environment. The shape of end cap 312 can be adapted to the shape of housing 311 to fit it. Optionally, end cap 312 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 312 is not easily deformed under pressure and impact, allowing battery cell 30 to have higher structural strength and improved reliability. Functional components such as electrode terminals can be provided on end cap 312. Electrode terminals can be used for electrical connection with electrode assembly 32 to output or input electrical energy to battery cell 30. The material of end cap 312 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating structure can also be provided on the inner side of end cap 312. The insulating structure can be used to isolate the electrical connection components inside housing 311 from end cap 312 to reduce the risk of short circuit. For example, the insulating structure can be made of plastic, rubber, etc.

[0108] Electrode assembly 32 is the component in the battery cell 30 where electrochemical reactions occur. The housing 311 may contain one or more electrode assemblies 32. The electrode assembly 32 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 to separate them and prevent short circuits between them to some extent. The portions of the positive and negative electrode sheets containing active material constitute the electrode body of the electrode assembly 32, while the portions without active material each constitute a tab. The positive and negative tabs can be located together at one end of the electrode body or separately at both ends. During the charging and discharging process of the battery cell 30, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0109] In a first aspect, as shown in Figures 4 and 5, the battery cell 30 provided in this embodiment includes a housing 31 and a pressure relief mechanism 40. The housing 31 includes a receiving cavity 30a and a first wall 313. The pressure relief mechanism 40 is disposed on the first wall 313 and includes a body portion 41 and an insulating portion 42. The material of the body portion 41 includes a metallic material. The insulating portion 42 is disposed on the side of the body portion 41 facing away from the receiving cavity 30a. The melting point T1 of the insulating portion 42 satisfies: T1≥400℃.

[0110] The housing 31 includes a receiving cavity 30a and a first wall 313. The receiving cavity 30a can be sealed to contain the electrolyte of the battery cell 30. The housing 31 may include a shell 311 and an end cap 312. The shell 311 has an opening, and the end cap 312 closes to the opening. The first wall 313 may be part of the shell 311, or the first wall 313 may be at least part of the end cap 312.

[0111] The battery cell 30 may include electrode terminals, which can be electrically connected to the tabs of the electrode assembly 32. The electrode terminals may be located on the first wall 313, or the electrode terminals may be located on the wall portion of the housing 31 opposite to the first wall 313. In other words, the pressure relief mechanism 40 may be located on the first wall 313 along with the electrode terminals, or the pressure relief mechanism 40 may be located opposite to the electrode terminals.

[0112] The body portion 41 of the pressure relief mechanism 40 is made of a metallic material. The body portion 41 can be the main load-bearing structure of the pressure relief mechanism 40 to maintain structural integrity during normal operation of the battery cell 30, thereby maintaining the sealing of the housing 30a of the battery cell 30. The body portion 41 can be made of the same material as the outer casing 31, such as aluminum alloy, to facilitate connection between the body portion 41 and the outer casing 31. For example, the body portion 41 can be formed by scoring or other means in a material such as aluminum alloy, so that when the internal pressure of the battery cell 30 reaches the pressure relief threshold of the battery cell 30, the body portion 41 can break and open in a timely manner, facilitating timely pressure relief of the battery cell 30.

[0113] The insulating part 42 is provided on the side of the main body 41 facing away from the receiving cavity 30a, that is, the insulating part 42 is provided on the side of the main body 41 facing the outside of the battery cell 30, so that when the pressure relief mechanism 40 is opened, the insulating part 42 flips outward along with the main body 41 to the outside of the battery cell 30, and the insulating part 42 contacts the conductive support member 50 outside the battery cell 30.

[0114] The insulating part 42 and the body part 41 may have the same or different shapes. Optionally, the body part 41 may be in the form of a sheet or a block, and similarly, the insulating part 42 may be in the form of a sheet, a block, or other irregular shapes.

[0115] The insulating part 42 can be integrally formed, or the insulating part 42 can be provided as a multi-layered structure composed of multiple different materials, and the materials of any two adjacent layers are different.

[0116] The insulating part 42 can be attached to the surface of the body part 41 by adhesive, or the insulating part 42 can be coated to the surface of the body part 41 by coating or other methods.

[0117] The insulating part 42 is provided on one side of the main body part 41. Optionally, the insulating part 42 can cover the entire arrangement of the main body part 41 on the side away from the receiving cavity 30a, or the insulating part 42 can cover a part of the arrangement of the main body part 41 on the side away from the receiving cavity 30a. The choice can be made according to actual needs.

[0118] The melting point T1 of the insulating part 42 is ≥400°C. For example, T1 can be 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, or higher. It is understood that in the event of thermal runaway of the battery cell 30, both the internal temperature and pressure of the battery cell 30 increase. Typically, the highest temperature range for thermal runaway of the battery cell 30 is around 400°C. Therefore, setting the melting point T1 of the insulating part 42 to ≥400°C ensures that the insulating part 42 will not melt in the event of thermal runaway of the battery cell 30. Thus, in the event of thermal runaway of the battery cell 30, the insulating part 42 flips together with the main body 41, and the insulating part 42 first contacts other conductive support members 50 outside the battery cell 30, reducing the risk of a short circuit inside the battery 10 caused by contact between the main body 41 and the support members 50.

[0119] Therefore, the battery cell 30 provided in this application embodiment includes a pressure relief mechanism 40 comprising a body portion 41 and an insulating portion 42, with the insulating portion 42 located on the side of the body portion 41 facing away from the receiving cavity 30a. The melting point T1 of the insulating portion 42 satisfies: T1≥400℃. In the event of thermal runaway of the battery cell 30, the pressure relief mechanism 40 opens, the insulating portion 42 does not melt and flips with the body portion 41. The pressure relief mechanism 40 connects with the conductive support member 50 inside the battery 10 through the insulating portion 42, which helps to reduce the risk of internal short circuit in the battery 10 and thereby improves the reliability of the battery 10.

[0120] In some embodiments, the insulating portion 42 covers the body portion 41.

[0121] Thus, the insulating portion 42 can be in the form of a continuous sheet, and the edge of the insulating portion 42 can be flush with the edge of the body portion 41, or the edge of the insulating portion 42 can extend beyond the edge of the body portion 41.

[0122] With the insulating part 42 covering the main body part 41, when the pressure relief mechanism 40 is flipped, it is further beneficial to reduce the risk of internal short circuit of battery 10 caused by contact between main body part 41 and support member 50, and to further improve the reliability of battery 10.

[0123] In some embodiments, as shown in FIG7, the insulating portion 42 has a through hole 42a, and the insulating portion 42 is arranged around the periphery of the through hole 42a.

[0124] Thus, the insulating part 42 can be ring-shaped. When the pressure relief mechanism 40 is flipped, the insulating part 42 contacts the support member 50. This reduces the risk of internal short circuit in the battery 10, and also helps to reduce the weight and quantity of the insulating part 42, thereby reducing the weight and production cost of the battery cell 30.

[0125] In some embodiments, the insulating portion 42 covers the outer edge of the body portion 41.

[0126] If the insulating portion 42 covers the outer edge of the body portion 41, then optionally, the outer edge of the insulating portion 42 may be flush with the outer edge of the body portion 41, or the outer edge of the insulating portion 42 may extend beyond the outer edge of the body portion 41 and extend outward.

[0127] Since the insulating part 42 has a through hole 42a and is provided to cover the outer edge of the main body part 41, when the pressure relief mechanism 40 releases pressure, after the pressure relief mechanism 40 flips outward, the insulating part 42 preferentially contacts the conductive support member 50 outside the battery cell 30. This is beneficial to further improve the insulation effect of the insulating part 42 on the main body part 41 and the conductive support member 50 outside the battery cell 30 while reducing the weight and amount of the insulating part 42, and further reduce the risk of internal short circuit of the battery 10.

[0128] In some embodiments, as shown in Figures 5 and 6, the body portion 41 is sheet-shaped.

[0129] In this way, the body part 41 occupies little space, which is convenient for processing and manufacturing. Moreover, the thickness of the body part 41 can be reasonably set according to the pressure relief threshold of the pressure relief mechanism 40, so as to improve the timeliness and accuracy of the opening of the pressure relief mechanism 40.

[0130] In some embodiments, as shown in FIG5, the insulating portion 42 is sheet-like.

[0131] Thus, the insulating part 42 occupies little space, making it easy to process and manufacture. Furthermore, the thickness of the insulating part 42 can be reasonably set according to the creepage distance requirements inside the battery 10, thereby reducing the risk of insulation failure of the insulating part 42.

[0132] In some embodiments, the insulating portion 42 is made of one of polyimide, ceramic, and mica.

[0133] Polyimide, ceramics, and mica can all meet the melting point requirements of the insulation part 42, and are relatively inexpensive and readily available. In the event of thermal runaway of the battery cell 30, the insulation part 42 can meet the insulation requirements of the body part 41 and the conductive support member 50, and helps to reduce the production cost of the battery cell 30.

[0134] In some embodiments, as shown in FIG8, the pressure relief mechanism 40 further includes a reinforcing part 43, which is disposed between the body part 41 and the insulating part 42.

[0135] The reinforcing part 43 can be in the form of a sheet, layer or block. The reinforcing part 43 can be bonded between the main body part 41 and the insulating part 42, or the reinforcing part 43 can be coated on the side of the main body part 41 facing away from the receiving cavity 30a.

[0136] The reinforcement part 43 can improve the overall structural strength of the pressure relief mechanism 40, reduce the risk of the pressure relief mechanism 40 being opened incorrectly due to vibration or impact loads during normal operation of the battery cell 30, and help improve the reliability of the battery cell 30.

[0137] In some embodiments, the reinforcing portion 43 includes a coating applied to the surface of the body portion 41 facing the insulating portion 42, and the melting point T2 of the coating satisfies: T2 < 400°C.

[0138] The reinforcing part 43 includes a coating. The specific thickness of the coating can be set according to the specific strength requirements of the pressure relief mechanism 40, and the coating can be formed by processes such as spraying, which facilitates the processing and manufacturing of the reinforcing part 43. If the melting point T2 of the coating is set to be less than 400℃, the coating can melt in time in the event of thermal runaway of the battery cell 30, allowing the pressure relief mechanism 40 to open promptly. This helps to reduce the risk of abnormal opening of the pressure relief mechanism 40 during normal operation of the battery cell 30, and also ensures that the pressure relief mechanism 40 opens promptly in the event of thermal runaway of the battery cell 30.

[0139] Therefore, the reinforcing part 43 is provided with a coating to facilitate the processing and manufacturing of the reinforcing part 43, and the melting point T2 of the coating is set to be less than 400°C, so that the coating can melt in time in the event of thermal runaway of the battery cell 30, so that the pressure relief mechanism 40 can be opened in time.

[0140] In some embodiments, as shown in FIG9, the pressure relief mechanism 40 further includes an insulating thermal expansion portion 44, which is disposed between the insulating portion 42 and the body portion 41, and is configured to expand and deform when heated.

[0141] The insulating thermal expansion part 44 has a certain insulating property and a certain coefficient of thermal expansion, so that it expands when heated.

[0142] Thus, when the battery cell 30 is operating normally, the insulating thermal expansion part 44 is in a compressed state and has a smaller volume, which helps to reduce the volume occupied by the pressure relief mechanism 40 and improve the energy density of the battery cell 30.

[0143] When the battery cell 30 is at risk of thermal runaway, the internal pressure and temperature of the battery cell 30 increase, and the insulating thermal expansion part 44 expands due to heat. When the internal pressure of the battery cell 30 reaches the pressure threshold of the pressure relief mechanism 40, the insulating thermal expansion part 44 flips over together with the main body part 41 and the insulating part 42. The thickness of the expanded insulating thermal expansion part 44 increases, which helps to increase the insulation distance between the conductive support member 50 on the outside of the battery cell 30 and the main body part 41, that is, it helps to increase the creepage distance between the support member 50 and the main body part 41.

[0144] Therefore, providing an insulating thermal expansion portion 44 between the main body portion 41 and the insulating portion 42 is beneficial for reducing the volume occupied by the pressure relief mechanism 40 and increasing the energy density of the battery cell 30, while also increasing the creepage distance between the main body portion 41 and the conductive support member 50 of the battery 10 in the event of thermal runaway of the battery cell 30, which further improves the reliability of the battery 10.

[0145] In some embodiments, the material of the insulating thermal expansion portion 44 is thermally expanded graphite.

[0146] Thermally expandable graphite is inexpensive and possesses excellent insulation properties and high temperature resistance. Furthermore, it has a high coefficient of thermal expansion. In the event of thermal runaway in the battery cell 30, the pressure relief mechanism 40 opens, and the insulating thermally expandable part 44 expands to a greater thickness while maintaining good insulation performance. Moreover, the structure of the thermally expandable graphite remains relatively intact even at high temperatures. This helps to further improve the insulation distance and insulation performance between the main body 41 and the conductive support member 50, thereby enhancing the reliability of the battery 10.

[0147] Secondly, as shown in FIG5, the battery 10 provided in the embodiments of this application includes a support member 50 and a battery cell 30 provided in any of the above embodiments. The support member 50 is disposed on one side of the first wall 313 of the battery cell 30. The material of the support member 50 includes a metal material. The support member 50 has a through hole 50a, which is disposed opposite to the pressure relief mechanism 40.

[0148] The through hole 50a can be provided through the support member 50. The through hole 50a is provided opposite to the pressure relief mechanism 40. Optionally, the through hole 50a can be provided opposite to part or all of the pressure relief mechanism 40 so that during the pressure relief process of the battery cell 30, the gas discharged from the battery cell 30 can be discharged through the hole 50a to the relevant exhaust channel 11a and finally discharged to the outside of the battery 10.

[0149] The support member 50 can be a plate-shaped structural member used to provide support for the battery cell 30. The support member 50 can form an airflow channel with the battery box 11 and other structures of the battery 10. During the depressurization process of the battery cell 30, the depressurization mechanism 40 of the battery cell 30 is opened, and the gas inside the battery cell 30 can enter the airflow channel through the through hole 50a and finally be discharged to the outside of the battery 10.

[0150] If the material of the support member 50 includes metal materials, the material of the support member 50 may include aluminum or steel, etc., to improve the supporting force of the support member 50.

[0151] The battery 10 provided in this application embodiment includes a pressure relief mechanism 40 for the battery cell 30, comprising a body portion 41 and an insulating portion 42. The insulating portion 42 is located on the side of the body portion 41 facing away from the receiving cavity 30a. The melting point T1 of the insulating portion 42 is ≥400°C. In the event of thermal runaway of the battery cell 30, the pressure relief mechanism 40 opens, the insulating portion 42 does not melt, and it flips together with the body portion 41. The pressure relief mechanism 40 is connected to the support member 50 through the insulating portion 42, which helps to reduce the risk of internal short circuit in the battery 10 and thus improves the reliability of the battery 10.

[0152] In some embodiments, as shown in FIG10, the insulating portion 42 is sheet-shaped, and the ratio of the thickness e of the insulating portion 42 to the maximum voltage U of the battery 10 is greater than or equal to 0.0005 and less than or equal to 0.02, where e is in millimeters and U is in volts.

[0153] Understandably, given a fixed maximum voltage for battery 10, a thicker insulating portion 42 is more beneficial for increasing the insulation distance between the main body 41 and the support member 50 when thermal runaway occurs in battery cell 30, in order to meet the relevant creepage distance requirements inside battery 10.

[0154] Optionally, the ratio of the thickness e of the insulating part 42 to the maximum voltage U of the battery 10 can be 0.0005, 0.00058, 0.0006, 0.0007 or 0.0008, etc.

[0155] To this end, the inventors conducted a series of experiments to prove the validity of the above relationship.

[0156] Specifically, a battery cell 30 with a casing size of 44mm*220mm*100mm and an energy density of 180Wh / Kg is used. These cells are connected in series to adjust different voltages. The battery cell 30 is then bonded to the support member 50. The pressure relief mechanism 40 of the battery cell 30 is a 60mm*70mm rectangle, and the through-hole 50a of the support member 50 is an 80mm*80mm rectangle. By changing the thickness of the insulation part 42, different e to U ratios are tested. Thermal runaway is controlled in the middle of the battery cell 30 using a built-in heating film. After the test, the cell is left to stand for 1 hour. A 500-volt DC current is applied to the positive terminal of the battery cell 30 to the support member 50 for 60 seconds, and the insulation resistance is tested. If the insulation resistance is greater than or equal to 1000Ω / V, the result is PASS, meaning the insulation part 42 meets the insulation requirements. If the resistance is less than 1000Ω / V, the structure is NG, meaning the insulation part 42 has failed.

[0157] The data from the relevant embodiments and comparative examples are shown in the table below:

[0158] According to the test results in the table above, it can be seen that setting the ratio of the thickness e of the insulating part 42 to the maximum voltage U of the battery 10 to be greater than or equal to 0.0005 is beneficial to reducing the risk of the insulating part 42 being broken down and causing insulation failure in the case of thermal runaway of the battery cell 30, and is beneficial to further improve the insulation performance of the insulating part 42.

[0159] Understandably, a larger e to U ratio reduces the risk of insulation failure due to the breakdown of the insulation portion 42 in the event of thermal runaway of the battery 10. Conversely, a smaller e value reduces the volume occupied by the insulation portion 42, thereby increasing the energy density of the battery cell 30.

[0160] Therefore, setting the ratio of the thickness e of the insulating part 42 to the maximum voltage U of the battery 10 to be greater than or equal to 0.0005 and less than or equal to 0.02 is beneficial to reducing the risk of insulation failure caused by the breakdown of the insulating part 42 in the event of thermal runaway of the battery cell 30, improving the insulation performance of the insulating part 42, reducing the volume occupied by the insulating part 42 inside the battery cell 30, and improving the energy density of the battery cell 30.

[0161] In some embodiments, the insulating portion 42 is sheet-like, and the ratio of the thickness e of the insulating portion 42 to the product of the creepage distance c of the battery 10 and the breakdown field strength E of the insulating portion 42 is greater than or equal to 0.00015, wherein e and c are in millimeters and E is in kilovolts per meter.

[0162] Typically, c = U / E, where E is the breakdown field strength of the insulation part 42, which can be measured by instruments such as electrostatic voltage or discharge sphere gap. However, considering the large amount of electrolyte and high temperature effects in the case of thermal runaway of the battery cell 30, the creepage distance is multiplied by a safety factor of 0.3 in practical applications, resulting in 0.3c = U / E. Combining the above, when e is in millimeters and U is in volts, the ratio of the value of e to the value of U satisfies that e / U is greater than or greater than 0.0005. Therefore, when e is in millimeters, c is in millimeters, and E is in kilovolts per meter, the ratio of e to the product of c and E, i.e., e / (c*E), is greater than or equal to 0.00015.

[0163] Optionally, the ratio of the thickness e of the insulating part 42 to the product of the creepage distance c of the battery 10 and the breakdown field strength E of the insulating part 42 can be 0.00015, 0.0002, 0.00025 or 0.0003, etc.

[0164] Therefore, after systematic analysis and long-term practice, the inventors found that setting the ratio of e to the product of the creepage distance c of the battery 10 and the breakdown field strength E of the insulation part 42 to be greater than or equal to 0.00015 is beneficial to reducing the risk of insulation failure of the insulation part 42 due to breakdown in the case of thermal runaway of the battery cell 30.

[0165] Further research by the inventors revealed that the ratio of the thickness e of the insulating part 42 to the product of the creepage distance c of the battery 10 and the breakdown field strength E of the insulating part 42 is greater than or equal to 0.00015 and less than or equal to 0.006, i.e., 0.00015≤e / (c*E)≤0.006. This is beneficial for reducing the insulation failure of the insulating part 42, as well as reducing the volume occupied by the insulating part 42 inside the battery 10, thereby increasing the energy density of the battery cell 30.

[0166] In some embodiments, as shown in Figures 7 and 11, the insulating portion 42 has a through hole 42a, and the insulating portion 42 is disposed around the periphery of the through hole 42a; the orthographic projection of the insulating portion 42 onto the first wall 313 is a first projection 431, the first projection 431 is annular, the first projection 431 has a first edge 431a and a second edge 431b, the second edge 431b is located inside the first edge 431a, and the ratio of the minimum distance d between the first edge 431a and the second edge 431b to the maximum voltage U of the battery 10 is greater than or equal to 0.0005, where the unit of d is millimeters and the unit of U is volts.

[0167] Optionally, the ratio of the minimum spacing d between the first edge 431a and the second edge 431b to the maximum voltage U of the battery 10 can be 0.0005, 0.0006, 0.0007, 0.0008, 0.0009, 0.001, or 0.002, etc.

[0168] It is understandable that the greater the distance d between the first edge 431a and the second edge 431b, the better it is to improve the insulation characteristics of the insulating part 42, while the smaller the distance between the first edge 431a and the second edge 431b, the better it is to reduce the weight of the insulating part 42.

[0169] After systematic analysis and a long period of time, the inventors discovered that setting the ratio of the minimum distance d between the first edge 431a and the second edge 431b to the maximum voltage U of the battery 10 to be greater than or equal to 0.0005 is beneficial in reducing the weight of the insulating part 42 and in the event of thermal runaway of the battery cell 30, it is beneficial in reducing the risk of insulation failure caused by the breakdown of the insulating part 42.

[0170] Thirdly, embodiments of this application provide an electrical device, which includes a battery cell 30 or a battery 10 provided in any of the above embodiments, wherein the battery 10 is used to provide electrical energy.

[0171] The power supply device provided in this application embodiment has the same technical effect because it uses the battery 10 provided in any of the above embodiments.

[0172] In some embodiments, as shown in Figures 4 to 11, the battery 10 includes a support member 50 and a battery cell 30. The battery cell 30 includes a housing 31 and a pressure relief mechanism 40. The housing 31 includes a receiving cavity 30a and a first wall 313. The pressure relief mechanism 40 is disposed on the first wall 313 and includes a body portion 41, an insulating portion 42, a reinforcing portion 43, and an insulating thermal expansion portion 44. The body portion 41 is made of a metallic material. The insulating portion 42 is disposed on the side of the body portion 41 facing away from the receiving cavity 30a. The melting point T1 of the insulating portion 42 satisfies: T1 ≥ 400°C. The body portion 41 is sheet-shaped, and the insulating portion 42 is sheet-shaped, covering the outer edge of the body portion 41. The insulating portion 42 is made of one of polyimide, ceramic, and mica. A reinforcing portion 43 is disposed between the body portion 41 and the insulating portion 42. The reinforcing portion 43 includes a coating applied to the surface of the body portion 41 facing the insulating portion 42. The melting point T2 of the coating satisfies the condition: T2 < 400°C. An insulating thermal expansion layer is disposed between the insulating portion 42 and the body portion 41. The insulating thermal expansion layer 44 is configured to expand and deform under heat. The material of the insulating thermal expansion layer 44 includes thermally expandable graphite. A support member 50 is disposed on one side of the first wall 313 of the battery cell 30. The material of the support member 50 includes a metallic material. The support member 50 has a through hole 50a, which is disposed opposite to the pressure relief mechanism 40. The ratio of the thickness e of the insulating portion 42 to the maximum voltage U of the battery 10 is greater than or equal to 0.0005 and less than or equal to 0.02, where e is in millimeters and U is in volts. The ratio of the product of the thickness e of the insulation part 42 and the creepage distance c of the battery 10 and the breakdown field strength E of the insulation part 42 is greater than or equal to 0.00015 and less than or equal to 0.006, where c is in millimeters and E is in kilovolts per meter.

[0173] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. 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 single battery cell, comprising: The outer casing includes a receiving cavity and a first wall; A pressure relief mechanism is provided on the first wall. The pressure relief mechanism includes a body part and an insulating part. The material of the body part includes a metal material. The insulating part is provided on the side of the body part facing away from the receiving cavity. The melting point T1 of the insulating part satisfies: T1≥400℃.

2. The battery cell according to claim 1, wherein, The insulating portion covers the body portion.

3. The battery cell according to claim 1 or 2, wherein, The insulating part has a through hole, and the insulating part is disposed around the periphery of the through hole.

4. The battery cell according to claim 3, wherein, The insulating portion covers the outer edge of the body portion.

5. The battery cell according to any one of claims 1 to 4, wherein, The body portion is sheet-shaped, and / or the insulating portion is sheet-shaped.

6. The battery cell according to any one of claims 1 to 5, wherein, The insulating material is one of polyimide, ceramic, and mica.

7. The battery cell according to any one of claims 1 to 6, wherein, The pressure relief mechanism also includes a reinforcing part, which is located between the body part and the insulating part.

8. The battery cell according to claim 7, wherein, The reinforcing part includes a coating applied to the surface of the body part facing the insulating part, and the melting point T2 of the coating satisfies: T2 < 400°C.

9. The battery cell according to any one of claims 1 to 8, wherein, The pressure relief mechanism also includes an insulating thermal expansion section, which is disposed between the insulating section and the body section. The insulating thermal expansion section is configured to expand and deform when heated.

10. The battery cell according to claim 9, wherein, The material of the insulating thermal expansion part is thermally expandable graphite.

11. A battery, comprising: The battery cell as described in any one of claims 1 to 10; A support member is disposed on one side of the first wall of the battery cell. The support member is made of a metal material and has a through hole, which is disposed opposite to the pressure relief mechanism.

12. The battery according to claim 11, wherein, The insulating part is sheet-like, and the ratio of the thickness e of the insulating part to the maximum voltage U of the battery is greater than or equal to 0.0005 and less than or equal to 0.02, where e is in millimeters and U is in volts.

13. The battery according to claim 11 or 12, wherein, The insulating part is sheet-like, and the ratio of the product of the thickness e of the insulating part and the creepage distance c of the battery and the breakdown field strength E of the insulating part is greater than or equal to 0.00015, where e and c are in millimeters and E is in kilovolts per meter.

14. The battery according to any one of claims 11 to 13, wherein, The insulating part has a through hole, and the insulating part is disposed around the periphery of the through hole; the orthographic projection of the insulating part onto the first wall is a first projection, the first projection is annular, the first projection has a first edge and a second edge, the second edge is located inside the first edge, and the ratio of the minimum distance d between the first edge and the second edge to the maximum voltage U of the battery is greater than or equal to 0.0005, where d is in millimeters and U is in volts.

15. An electrical device comprising a battery cell as claimed in any one of claims 1 to 10 or a battery as claimed in any one of claims 11 to 14, the battery being used to provide electrical energy.

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