Battery cell, battery, and electric device

Abstract

The application discloses a battery monomer, a battery and a power utilization device. The battery monomer comprises an electrode assembly, a shell, a pressure relief mechanism, and a support part. The shell comprises a first wall part. The support part is formed on the first wall part and at least partially arranged on a side of the first wall part close to the electrode assembly. The support part is located at least one side of the pressure relief mechanism in a third direction and is formed with an exhaust passage. The exhaust passage is arranged through the support part in the third direction. In the technical scheme of the application, the exhaust passage extending in the third direction can guide the gas to be discharged in the thermal runaway, so as to reduce the probability of non-directional pressure relief caused by internal pressure accumulation. The support part is directly formed on the first wall part, so that the assembly process and the material cost are not greatly increased, and the problem of support failure caused by melting at high temperature can be avoided, the probability of non-directional pressure relief caused by internal pressure accumulation is further reduced, and the reliability of the battery monomer is improved.

Description

Technical Field

[0001] This application relates to the field of batteries, specifically to a battery cell, a battery, and an electrical device. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] Each battery cell is equipped with a pressure relief mechanism. In the event of thermal runaway, the gas generated inside the battery cell needs to reach the pressure relief mechanism smoothly to achieve directional pressure relief. However, currently, there is a risk of non-directional pressure relief during the charging and discharging process of batteries. Utility Model Content

[0004] In view of the above problems, this application provides a battery cell, a battery, and an electrical device that can alleviate the problem of non-directional pressure leakage.

[0005] In a first aspect, this application provides a battery cell, comprising: an electrode assembly including at least one positive electrode, at least one negative electrode, and at least one separator, the separator being used to isolate the positive electrode and the negative electrode, the electrode assembly including a flat region, at least a portion of the positive electrode, at least a portion of the negative electrode, and at least a portion of the separator being stacked in the flat region along a first direction; a housing for accommodating the electrode assembly, the housing including a first wall portion located on one side of the electrode assembly in a second direction; a pressure relief mechanism disposed on the first wall portion, the pressure relief mechanism being at least partially capable of opening when the battery cell is depressurized; the first wall portion having a support portion, at least a portion of the support portion being disposed on the side of the first wall portion near the electrode assembly, the support portion being located on at least one side of the pressure relief mechanism in a third direction and forming an exhaust channel, the exhaust channel being disposed through the support portion along the third direction, the third direction, the second direction, and the first direction of the first wall portion being perpendicular to each other.

[0006] In the technical solution of this application embodiment, the support portion can provide an exhaust channel extending upwards in the third direction. This allows gas to be guided along the exhaust channel to the pressure relief mechanism during thermal runaway, reducing the probability of non-directional pressure relief caused by internal pressure buildup and improving the reliability of the battery cell. Furthermore, the support portion is directly formed on the first wall portion, eliminating the need for additional components and avoiding a significant increase in assembly process and material costs. It also prevents the problem of support failure due to melting at high temperatures, ensuring that the battery cell still provides support for the electrode assembly during thermal runaway. There is always a certain exhaust channel between the electrode assembly and the first wall portion, further reducing the probability of non-directional pressure relief caused by internal pressure buildup and improving the reliability of the battery cell.

[0007] In some embodiments, the support portion includes a plurality of sub-support portions, which are symmetrically arranged on both sides of the pressure relief mechanism in the third direction. In the above technical solution, sub-support portions are provided on both sides of the pressure relief mechanism, that is, the pressure relief mechanism has exhaust channels on both sides in the third direction, so that the high-temperature gas on both sides of the electrode assembly can be quickly discharged through the exhaust channels and the pressure relief mechanism.

[0008] In some embodiments, a plurality of the sub-support portions are arranged symmetrically with respect to the center of the first wall portion in the first direction. This arrangement ensures a uniform distribution of the sub-support portions, improving the support effect and stability.

[0009] In some embodiments, a plurality of the sub-supports are arranged at intervals in the first direction, and an exhaust channel is formed between two adjacent sub-supports; and / or, an exhaust channel is formed between the sub-support and other wall portions of the housing. In the above technical solution, multiple exhaust channels can be formed by the sub-supports, which can improve exhaust efficiency and enable the high-temperature gas on both sides of the electrode assembly to be discharged quickly.

[0010] In some embodiments, in the third direction, the support portion and the pressure relief mechanism are arranged at a distance, and in the third direction, the shortest distance between the support portion and the pressure relief mechanism is x, satisfying: 3mm≤x≤20mm. This technical solution facilitates manufacturing, reduces deformation at the groove, minimizes local protrusions, and provides some support for the electrode assembly, reducing the probability of non-directional pressure relief due to internal pressure buildup, and to some extent preventing an increase in burst pressure.

[0011] In some embodiments, the pressure relief mechanism has multiple exhaust channels on any side in the third direction, and the multiple exhaust channels are symmetrically arranged with respect to the center of the first wall. In the above technical solution, by setting multiple exhaust channels, the exhaust space is increased without affecting the support effect of the support part, thereby increasing the gas discharge speed. In addition, the symmetrical arrangement of the exhaust channels makes the support effect of the support part more uniform, and high-temperature gas at different positions can be quickly and evenly discharged through the exhaust channels and the pressure relief mechanism.

[0012] In some embodiments, a support surface is formed on the side of the support portion near the electrode assembly, and the support surface is a plane parallel to the surface of the first wall portion. In the above technical solution, the electrode assembly will not be misaligned, creating an exhaust channel between the electrode assembly and the first wall portion, thereby improving the flow efficiency of high-temperature gas to the pressure relief mechanism. The high-temperature gas can be quickly discharged to the outside of the battery cell through the exhaust channel and the pressure relief mechanism. Furthermore, the top of the support portion is flat, which can reduce damage to the electrode assembly caused by local protrusions and improve the reliability of the battery cell.

[0013] In some embodiments, the support portion includes multiple sub-support portions, the total area of ​​the support surfaces of the multiple sub-support portions is S1, and the area of ​​the first wall portion is S2, satisfying: 0.3≤S1 / S2≤0.7, preferably, 0.4≤S1 / S2≤0.7. In the above technical solution, the supporting effect of the support portion can be improved, providing a certain exhaust channel between the electrode assembly and the first wall portion, while also meeting the pressure relief requirements for exhaust area, thereby improving the reliability of the battery cell.

[0014] In some embodiments, the minimum dimensions of the support surface in the first and third directions are w1, satisfying: 1.5mm ≤ w1 ≤ 4mm. This technical solution facilitates manufacturing and improves manufacturing yield, while also reducing the probability of localized stress on the electrode assembly from the support portion, thus improving the reliability of the battery cell.

[0015] In some embodiments, the first wall portion has a first inner surface and a first outer surface, the first inner surface being closer to the electrode assembly than the first outer surface, the distance between the support surface and the first inner surface in a second direction being h1, and the capacity of the battery cell being C, satisfying: 35 Ah / mm ≤ C / h1 ≤ 400 Ah / mm. In the above technical solution, both exhaust requirements and certain energy density requirements can be met, avoiding excessive reduction in energy density to a certain extent.

[0016] In some embodiments, an insulating member is provided within the housing, the insulating member being located between the support portion and the electrode assembly, and the support surface abutting against the insulating member to support the insulating member. In the above technical solution, the support surface directly abuts against the insulating member, thereby achieving the supporting function of the support portion for the electrode assembly and the insulating member, and improving the reliability of the support.

[0017] In some embodiments, an insulating film is provided on the outer periphery of the electrode assembly, and the supporting surface abuts against the insulating film to support the insulating film and the electrode assembly. In the above technical solution, the supporting surface directly abuts against the insulating film, realizing the supporting function of the supporting part for the electrode assembly, and the insulating film can effectively isolate the direct contact between the electrode assembly and the supporting part, preventing short circuits from occurring.

[0018] In some embodiments, the support portion is integrally formed with the first wall portion. In the above technical solutions, the manufacturing process of the support portion is simple, facilitating its manufacturing and forming.

[0019] In some embodiments, the pressure relief mechanism is integrally formed with the first wall portion. In the above technical solution, by integrally forming the pressure relief mechanism with the first wall portion, the reliability of the pressure relief mechanism can be improved, the connection process between the pressure relief mechanism and the first wall portion can be eliminated, and the manufacturing cost of the battery cell can be reduced.

[0020] In some embodiments, the pressure relief mechanism is provided with a groove, the groove including a first groove. A portion of the first wall is punched towards the electrode assembly to form the first groove, and another portion of the first wall is punched towards the electrode assembly to form the support portion. The support portion protrudes from the first wall at a greater height than the first groove protrudes from the first wall. In the above technical solution, the support portion protrudes from the inner surface of the first wall at a greater height than the first groove. A certain exhaust channel exists between the electrode assembly and the first wall, extending in a third direction. High-temperature gas between the electrode assembly and the third wall can be discharged to the pressure relief mechanism through the exhaust channel, and then discharged through the pressure relief mechanism, reducing the probability of non-directional pressure relief caused by internal pressure buildup and improving the reliability of the battery cell.

[0021] In some embodiments, the pressure relief mechanism is separately disposed from the first wall portion, the first wall portion having a pressure relief hole, and the pressure relief mechanism being installed in the pressure relief hole. In the above technical solution, the pressure relief mechanism is a component independent of the outer shell, and the pressure relief mechanism and the outer shell can be manufactured and reassembled separately, resulting in low manufacturing difficulty and high efficiency.

[0022] In some embodiments, the housing includes a shell and an end cap, the shell having an opening at at least one end along a second direction, the end cap being connected to the shell and used to close the opening, and the first wall portion being formed in the shell. In the above technical solution, the structure of the end cap can be simplified, and the distance between the pressure relief mechanism and the main body of the electrode assembly can be shortened. This shortens the path of the discharge medium to the pressure relief mechanism during pressure relief, reduces the time it takes for the discharge medium to reach the pressure relief mechanism, improves the timeliness of pressure relief for the battery cell, and thus effectively improves the reliability of the battery cell.

[0023] In some embodiments, the first wall portion is used to support the electrode assembly and is located below the electrode assembly.

[0024] In the above technical solution, the pressure relief mechanism can be located at the bottom of the battery cell. The bottom of the battery cell can be provided with an exhaust channel, which can be connected to the pressure relief mechanism. In the event of thermal runaway of the battery cell, the high-temperature and high-pressure flue gas can be discharged through the pressure relief mechanism at the bottom into the exhaust channel and then discharged to the outside.

[0025] Secondly, this application provides a battery that includes the battery cell described in the above embodiments.

[0026] Thirdly, this application provides an electrical device that includes the battery described in the above embodiments, the battery being used to provide electrical energy.

[0027] 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

[0028] 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:

[0029] Figure 1 This is a schematic diagram of an electrical device in related technologies;

[0030] Figure 2 This is a schematic diagram of a battery in a related technology;

[0031] Figure 3 This is a schematic diagram of a single battery cell in the relevant technology;

[0032] Figure 4 Here are exploded views of individual battery cells from some embodiments of this application;

[0033] Figure 5 A schematic diagram of an electrode assembly provided in some embodiments of this application;

[0034] Figure 6 A schematic diagram of an electrode assembly provided for other embodiments of this application;

[0035] Figure 7 Schematic diagram of the housing provided for some embodiments of this application;

[0036] Figure 8 Top view of the housing provided for some embodiments of this application;

[0037] Figure 9 Bottom view of the housing provided for some embodiments of this application;

[0038] Figure 10 For along Figure 9 Sectional view of line AA in the middle;

[0039] Figure 11 for Figure 10 The center circle shows a magnified view of point C;

[0040] Figure 12 For along Figure 9 Sectional view of the middle BB line;

[0041] Figure 13 for Figure 12 The center circle shows a magnified view of point D.

[0042] Figure label:

[0043] 1000 batteries, 2000 electrical devices

[0044] Battery cell 100, casing 200, first shell 201, second shell 202.

[0045] Outer shell 10, housing 101, end cap 102, first wall portion 11, first inner surface 1101, first outer surface 1102, second wall portion 12, third wall portion 13, support portion 14, sub-support portion 1401, support surface 141, exhaust channel 142.

[0046] Electrode assembly 20, positive electrode 21, negative electrode 22, straight section 23, bending section 24, separator 25, insulating film 26.

[0047] Electrical connection part 30,

[0048] Pressure relief mechanism 40, groove 402, first groove 41, second groove 42

[0049] First direction F1, second direction F2, third direction F3. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] 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.

[0052] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0053] 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.

[0054] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0055] In this application, "multiple" means two or more (including two).

[0056] In this embodiment, the battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this embodiment is not limited to these types.

[0057] The battery mentioned in the embodiments of this application may be a single physical module comprising one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or mixed via a busbar.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0062] The development of battery technology must consider multiple design factors simultaneously, such as performance parameters like energy density, cycle life, discharge capacity, and charge / discharge rate. Additionally, battery safety must also be considered. To ensure the safety of individual battery cells, pressure relief mechanisms can be installed on their casings. In the event of thermal runaway, these mechanisms release internal pressure, thereby improving the safety of the battery cell.

[0063] However, some of the grooves on the pressure relief mechanism 40 protrude into the battery cell 100, which may encroach on the exhaust space between the electrode assembly 20 and the outer casing 10. This may cause the gas generated when the battery cell thermally runs away to be unable to reach the pressure relief mechanism 40, resulting in the risk of non-directional pressure relief due to internal pressure buildup.

[0064] Some designs incorporate an insulating base plate between the electrode assembly 20 and the housing 10. This base plate is typically made of a non-high-temperature resistant material. During thermal runaway, the internal temperature is high, and the base plate will melt and lose its supporting function. However, using materials that are compatible with both high-temperature resistance and electrolyte corrosion resistance would significantly increase material costs.

[0065] To this end, this application proposes a battery cell 100, comprising: an electrode assembly 20, a housing 10, a pressure relief mechanism 40, and a support portion 14. The electrode assembly 20 includes at least one positive electrode 21, at least one negative electrode 22, and at least one separator 25. The separator 25 is used to isolate the positive electrode 21 and the negative electrode 22. The electrode assembly 20 includes a flat region 23, and at least a portion of the positive electrode 21, at least a portion of the negative electrode 22, and at least a portion of the separator 25 are stacked in the flat region 23 along a first direction F1. The housing 10 is used to accommodate the electrode assembly 20 and includes a first wall portion 11 located on one side of the electrode assembly 20 in a second direction F2. The pressure relief mechanism 40 is disposed on the first wall portion 11, and at least a portion of the pressure relief mechanism 40 can be opened when the battery cell 100 is depressurized.

[0066] A support portion 14 is provided on the first wall portion 11. At least a portion of the support portion 14 is provided on the side of the first wall portion 11 near the electrode assembly 20. The support portion 14 is located on at least one side of the pressure relief mechanism 40 in the third direction F3 and forms an exhaust channel 142. The exhaust channel 142 is provided to pass through the support portion 14 along the third direction F3. The third direction F3, the second direction F2 and the first direction F1 of the first wall portion 11 are perpendicular to each other.

[0067] In the battery cell 100 with the above-described structure, by providing a support portion 14 on the first wall portion 11, the support portion 14 can provide an exhaust channel 142 extending in the third direction F3, thereby guiding the gas along the exhaust channel 142 to the pressure relief mechanism 40 in the event of thermal runaway, reducing the probability of non-directional pressure relief caused by internal pressure buildup, and improving the reliability of the battery cell 100.

[0068] Furthermore, the support portion 14 is directly formed on the first wall portion 11, eliminating the need for additional components and avoiding a significant increase in assembly process and material costs. It also prevents the support from failing due to melting at high temperatures, ensuring that the electrode assembly 20 continues to provide support even when the battery cell 100 experiences thermal runaway. There is always a certain venting channel between the electrode assembly 20 and the first wall portion 11, further reducing the probability of non-directional pressure release caused by internal pressure buildup and improving the reliability of the battery cell 100.

[0069] The technical solutions described in the embodiments of this application are applicable to batteries and electrical devices that use batteries.

[0070] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0071] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0072] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 2000 provided in some embodiments of this application. A battery 1000 is disposed inside the vehicle 2000, and the battery 1000 may be located at the bottom, front, or rear of the vehicle 2000. The battery 1000 can be used to power the vehicle 2000; for example, the battery 1000 can serve as the operating power source for the vehicle 2000.

[0073] The vehicle 2000 may also include a controller and a motor. The controller is used to control the battery 1000 to power the motor, for example, to meet the power requirements of the vehicle 2000 during startup, navigation and driving.

[0074] In some embodiments of this application, the battery 1000 can not only serve as the operating power source for the vehicle 2000, but also as the driving power source for the vehicle 2000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 2000.

[0075] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery 1000 provided in some embodiments of this application. The battery 1000 includes a battery cell 100 and a housing 200 for housing the battery cell 100.

[0076] The housing 200 is a component that houses the battery cell 100, providing a placement space for the battery cell 100. The housing 200 can adopt various structures. In some embodiments, the housing 200 may include a first shell 201 and a second shell 202, which overlap each other to define a placement space for accommodating the battery cell 100. The first shell 201 and the second shell 202 can be various shapes, such as cuboids, cylinders, etc. The first shell 201 can be a hollow structure open on one side, and the second shell 202 can also be a hollow structure open on one side. When the open side of the second shell 202 overlaps the open side of the first shell 201, a housing 200 with a placement space is formed. Alternatively, the first shell 201 can be a hollow structure open on one side, and the second shell 202 can be a plate-like structure, overlapping the open side of the first shell 201 to form a housing 200 with a placement space. As an example, the battery cell 100 can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell 100 of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0077] In battery 1000, there can be one or more battery cells 100. If there are multiple battery cells 100, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 100 are connected in both series and parallel. Alternatively, multiple battery cells 100 can be first connected in series, parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 200. Another option is that all battery cells 100 can be directly connected in series, parallel, or in a mixed configuration, and then the whole consisting of all battery cells 100 is housed within the housing 200.

[0078] Please refer to Figure 3 and Figure 4 , Figure 3 A schematic diagram of a battery cell 100 provided in some embodiments of this application; Figure 4 This is an exploded view of a battery cell 100 provided in some embodiments of this application. The battery cell 10 may include a housing 10 and an electrode assembly 20.

[0079] The housing 10 is used to house the electrode assembly 20 and electrolyte components. The housing 10 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. As an example, the housing 10 may include a housing 101 and an end cap 102.

[0080] The housing 101 can be a hollow structure with an opening at one end, or it can be a hollow structure with openings at both opposite ends. The housing 101 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0081] End cap 102 is a component that closes the opening of housing 101 to isolate the internal environment of battery cell 100 from the external environment. End cap 102 and housing 101 together define a space for accommodating electrode assembly 20, electrolyte, and other components. End cap 102 can be connected to housing 101 by welding or roll sealing to close the opening of housing 101. The shape of end cap 102 can be adapted to the shape of housing 10; for example, if housing 101 is a cuboid structure, end cap 102 can be a rectangular plate structure adapted to housing 10. End cap 102 can also be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0082] In the battery cell 10, there can be one or two end caps 102. In an embodiment where the housing 101 is a hollow structure with openings at both ends, two end caps 102 can be provided, each closing one of the two openings of the housing 101, and the two end caps 102 together with the housing 101 define an accommodating space. In an embodiment where the housing 101 is a hollow structure with an opening at one end, one end cap 102 can be provided, closing one opening of the housing 101, and the one end cap 102 together with the housing 101 define an accommodating space.

[0083] The electrode assembly 20 includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell 100, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator is disposed between the positive and negative electrodes to prevent short circuits between them while allowing active ions to pass through.

[0084] In some embodiments, the positive electrode can be a positive electrode sheet 21, and the positive electrode sheet 22 can include a positive current collector and a positive active material region disposed on at least one surface of the positive current collector, the positive active material region having a positive active material.

[0085] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material region is disposed on either or both of the two opposite surfaces of the positive current collector.

[0086] In some embodiments, the negative electrode may be a negative electrode sheet 22, which may include a negative electrode current collector and a negative electrode active material region disposed on at least one surface of the negative electrode current collector.

[0087] 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 region is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0088] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0089] In some embodiments, the electrode assembly 20 further includes an isolator disposed between the positive and negative electrodes.

[0090] 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.

[0091] In some embodiments, the separator is a solid electrolyte, disposed between the positive and negative electrodes, serving to both transport ions and isolate the positive and negative electrodes.

[0092] In some embodiments, the battery cell 100 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-like, or solid.

[0093] In some embodiments, the electrode assembly 20 is a wound structure. The positive electrode, the negative electrode, and the separator are wound into a wound structure.

[0094] In some embodiments, the electrode assembly 20 has a stacked structure.

[0095] As an example, multiple positive electrode plates 21, multiple negative electrode plates 22 and multiple separators 25 can be provided respectively, and multiple positive electrode plates 21, multiple negative electrode plates 22 and multiple separators 25 can be stacked alternately.

[0096] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0097] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0098] In some embodiments, the electrode assembly 20 may be flat or polygonal in shape.

[0099] In some embodiments, the electrode assembly 20 is provided with tabs that can conduct current from the electrode assembly 20. The tabs include a positive tab and a negative tab.

[0100] The battery cell 100 may further include an electrical connection portion 30, which may be disposed on the housing 10. The electrical connection portion 30 is used for electrical connection with the tabs of the electrode assembly 20 to output electrical energy from the battery cell 10. The electrical connection portion 30 and the tabs may be directly connected, for example, by direct welding. The electrical connection portion 30 and the tabs may also be indirectly connected, for example, by indirect connection through a current collector. The current collector may be a metallic conductor, such as copper, iron, aluminum, steel, or aluminum alloy.

[0101] like Figure 3 and Figure 4 As shown, taking the shell 101 as a hollow structure with an opening at one end as an example, two electrical connection parts 30 can be provided on the end cover 102. The two electrical connection parts 30 are a positive electrical connection part and a negative electrical connection part, respectively. The positive electrical connection part is electrically connected to the positive electrode tab, and the negative electrical connection part is electrically connected to the negative electrode tab.

[0102] Please refer to Figure 5 and Figure 6 , Figure 5 A schematic diagram of the electrode assembly 20 provided in some embodiments of this application; Figure 6 This is a schematic diagram of an electrode assembly 20 provided in other embodiments of this application. The electrode assembly 20 includes a positive electrode plate 21 and a negative electrode plate 22. The positive electrode plate 21 includes a positive electrode body and a positive electrode tab. The positive electrode tab extends from one end of the positive electrode body. Most of the area of ​​the positive electrode tab is not coated with positive active material, while most of the area of ​​the positive electrode body is coated with positive active material. The negative electrode plate 22 includes a negative electrode body and a negative electrode tab. The negative electrode tab extends from one end of the negative electrode body. Most of the area of ​​the negative electrode tab is not coated with negative active material, while most of the area of ​​the negative electrode body is coated with negative active material. The positive electrode body and the negative electrode body constitute the main body of the electrode assembly.

[0103] like Figure 5 As shown, the electrode assembly 20 includes a plurality of wound electrodes, and the electrode assembly 20 includes a flat region 23 and a bend region 24 connected to the end of the flat region 23.

[0104] Multiple electrode sheets arranged in a wound configuration, namely positive electrode sheet 21 and negative electrode sheet 22, are stacked and wound around a predetermined axis to form an electrode assembly 20. The straight region 23 refers to the portion of the electrode sheet extending along a plane after winding; the curved region 24 refers to the portion of the electrode sheet extending along an arc surface after winding, for example... Figure 5 As shown, the portion between the front and rear surfaces of the electrode assembly 20 is formed as a flat region 23. Within the flat region 23, the extending direction of the electrode sheet is the length direction of the flat region 23. Figure 5 As shown, within the straight section 23, the left and right ends of the straight section 23 are the turning sections 24.

[0105] like Figure 6 As shown, electrode assembly 120 includes multiple electrode sheets arranged in layers, and electrode assembly 20 has a flat region 23.

[0106] Multiple electrode sheets arranged in a stacked manner, such as at least one positive electrode sheet 21 and at least one negative electrode sheet 22, are stacked to form an electrode assembly 20. The flat region 23 is formed by stacking at least a portion of the positive electrode sheet 21 and the negative electrode sheet 22, or it can be formed by stacking at least a portion of the positive electrode sheet 21 and the negative electrode sheet 22. The extension direction of the electrode sheets in the flat region 23 is the length direction of the flat region 23.

[0107] Please refer to Figures 7-13 , Figures 7-13 Here are some schematic diagrams of the casings in this application; combined with Figures 4-13 As shown, the battery cell 100 according to an embodiment of this application includes: an electrode assembly 20, the electrode assembly 20 including at least one positive electrode 21, at least one negative electrode 22 and at least one separator 25, the separator 25 being used to isolate the positive electrode 21 and the negative electrode 22, the electrode assembly 20 including a flat region 23, at least a portion of the positive electrode 21, at least a portion of the negative electrode 22 and at least a portion of the separator 25 being stacked in the flat region 23 along a first direction F1.

[0108] The electrode assembly 20 can be a stacked type, that is, multiple electrodes of the electrode assembly 20 are stacked and arranged in layers. After the electrodes are stacked, a flat area 23 is formed. The electrode assembly 20 is in a stacked state. In the flat area 23, at least a portion of the positive electrode 21, the negative electrode 22 and the separator 25 are stacked along the first direction F1.

[0109] The electrode assembly 20 can also be wound. The positive electrode 21 and negative electrode 22 of the electrode assembly 20 are stacked and wound with the separator 25, forming a straight area 23 and a bend area 24. The straight area 23 refers to the part of the electrode extending along the plane after winding. The electrode assembly 20 is stacked in the straight area 23. The bend area 24 refers to the part of the electrode extending along the arc surface after winding. The outer surface of the bend area 24 is at least partially arc surface. The straight area 23 connects the two bend areas 24. In the straight area 23, the positive electrode 21, the negative electrode 22 and the separator 25 are stacked along the first direction F1. For example, after winding, each layer of the positive electrode 21, each layer of the negative electrode 22 and each layer of the separator 25 can be penetrated by a straight line extending along the first direction F1.

[0110] An insulating film 26 is provided on the outside of the electrode assembly 20. The insulating film 26 covers at least a portion of the electrode assembly 20, thereby insulating the electrode assembly 20 from the outer casing 10.

[0111] The positive electrode 21 includes a positive electrode body and a positive electrode tab. The positive electrode tab protrudes from the positive electrode body in the second direction F2. Most or all of the positive electrode body is coated with positive active material. Most or all of the positive electrode tab is not coated with positive active material. A small amount of insulating layer may be coated on the edge of the positive electrode body.

[0112] Correspondingly, the negative electrode sheet 22 includes a negative electrode body and a negative electrode tab. The negative electrode tab protrudes from the negative electrode body in the second direction F2. Most or all of the negative electrode body is coated with negative electrode active material, while most or all of the negative electrode tab is not coated with negative electrode active material.

[0113] The battery cell 100 also includes a housing 10 for accommodating the electrode assembly 20. The housing 10 includes a first wall 11 located on one side of the electrode assembly 20 in the second direction F2.

[0114] Combination Figure 4 As shown, the outer casing 10 includes a first wall portion 11, two second wall portions 12 and two third wall portions 13. The electrode assembly 20 is assembled inside the outer casing 10. The two second wall portions 12 are located on both sides of the electrode assembly 20 in the first direction F1, and the two third wall portions 13 are located on both sides of the electrode assembly 20 in the third direction F1. The first wall portion 11 is located on one side of the electrode assembly 20 in the second direction F2. The second direction F2 is perpendicular to the first direction F1, and the thickness direction of the first wall portion 11 is the second direction F2.

[0115] The battery cell 100 also includes a pressure relief mechanism 40 disposed on the first wall portion 11, and the pressure relief mechanism 40 is at least partially capable of opening when the battery cell 100 is depressurized.

[0116] The pressure relief mechanism 40 is provided with a groove 402. The pressure relief mechanism 40 is a component used to release the internal pressure of the battery cell 100. When the internal pressure of the battery cell 100 reaches a threshold, the pressure relief mechanism 40 discharges the discharge medium inside the battery cell 100 to achieve the purpose of pressure relief. The threshold design varies depending on the design requirements. The threshold may depend on one or more materials among the positive electrode 21, negative electrode 22, electrolyte and separator in the battery cell 100.

[0117] like Figures 7-13 As shown, a support portion 14 is provided on the first wall portion 11, and at least a portion of the support portion 14 is provided on the side of the first wall portion 11 near the electrode assembly 20. The support portion 14 is located on at least one side of the pressure relief mechanism 40 in the third direction F3 and forms an exhaust channel 142. The exhaust channel 142 is provided to pass through the support portion 14 along the third direction F3. The third direction F3, the second direction F2 and the first direction F1 of the first wall portion 11 are perpendicular to each other.

[0118] The support portion 14 can be formed on the first wall portion 11 by a stamping process, so that the first wall portion 11 is partially arched to form the support portion 14. Alternatively, the support portion 14 can be integrally formed on the first wall portion 11 by a manufacturing process, so that the support portion 14 protrudes from one side surface of the first wall portion 11 and is formed on the first wall portion 11, thus eliminating the need for additional fixing of the support portion 14.

[0119] The support portion 14 can directly support the insulating film 26 on the outside of the electrode assembly 20. An insulating element can also be provided between the electrode assembly 20 and the first wall portion 11, and the support portion 14 can also directly support the insulating element.

[0120] An exhaust channel 142 is formed by setting a support portion 14. The exhaust channel 142 can be formed by the support portion 14 itself or by the support portion 14 and the second wall portion 12 being arranged at intervals. The exhaust channel 142 passes through both ends of the support portion 14 along the third direction F3, thereby extending the exhaust channel 142 along the third direction F3, and the exhaust channel 142 can be connected to the pressure relief mechanism 40.

[0121] The gap between the electrode assembly 20 and the second wall portion 12 on both sides in the first direction F1 is relatively small. There is a certain gap between the electrode assembly 20 and the third wall portion 13 on both sides in the third direction F3. In particular, for the wound electrode assembly 20, the setting of the bend area 24 makes the space between the electrode assembly 20 and the third wall portion 13 relatively large. When the battery cell 100 experiences thermal runaway, high-temperature gas fills the space between the electrode assembly 20 and the third wall portion 13.

[0122] A support portion 14 is provided on the first wall portion 11. The support portion 14 can protrude from the surface of the first wall portion 11 near the electrode assembly 20, thereby creating a certain exhaust channel 12 between the electrode assembly 20 and the first wall portion 11. The exhaust channel 12 extends along the third direction F3, and the high-temperature gas between the electrode assembly 20 and the third wall portion 13 can be discharged to the pressure relief mechanism 40 through the exhaust channel, and then discharged through the pressure relief mechanism 40.

[0123] In the technical solution of this application embodiment, the support part 14 can provide an exhaust channel 12 extending in the third direction F3, thereby guiding the gas along the exhaust channel 142 to the pressure relief mechanism 40 during thermal runaway, reducing the probability of non-directional pressure relief caused by internal pressure buildup, and improving the reliability of the battery cell 100.

[0124] Furthermore, the support portion 14 is directly formed on the first wall portion 11, eliminating the need for additional components and avoiding a significant increase in assembly process and material costs. It also prevents the support from failing due to melting at high temperatures, ensuring that the battery cell 100 still provides support for the electrode assembly 20 during thermal runaway. There is always a certain venting channel 142 between the electrode assembly 20 and the first wall portion 11, further reducing the probability of non-directional pressure relief caused by internal pressure buildup and improving the reliability of the battery cell 100.

[0125] like Figure 8 and Figure 9 As shown, in some embodiments, the support portion 14 includes a plurality of sub-support portions 1401, which are symmetrically arranged on both sides of the pressure relief mechanism 40 in the third direction F3. Thus, the pressure relief mechanism 40 has support portions 14 on both sides, meaning that the pressure relief mechanism 40 has exhaust channels 142 on both sides in the third direction F3, allowing the high-temperature gas on both sides of the electrode assembly 20 to be quickly discharged through the exhaust channels 142 and the pressure relief mechanism 40.

[0126] like Figure 8 and Figure 9 As shown, in some embodiments, a plurality of sub-supports 1401 are arranged symmetrically with respect to the center of the first wall portion 11 in the first direction F1. The center of the first wall portion 11 and the center of the pressure relief mechanism 40 may coincide, such as... Figure 8 As shown, multiple sub-supports 1401 are arranged symmetrically with respect to the center of the first wall portion 11 in the first direction F1 and the third direction F3, thereby making the distribution of the support portions 14 uniform and improving the support effect and stability.

[0127] In some embodiments, a plurality of sub-support portions 1401 are arranged at intervals in a first direction F1, and an exhaust channel 142 is formed between two adjacent sub-support portions 1401; and / or, an exhaust channel 142 is formed between the sub-support portion 1401 and other wall portions of the housing 10.

[0128] like Figure 8 As shown, the sub-support 1401 extends along the third direction F3, and multiple sub-supports 1401 are arranged at intervals in the first direction F1. An exhaust channel 142 is formed between two adjacent sub-supports 1401, and an exhaust channel 142 is formed between the sub-support 1401 and the second wall portion 12 of the outer casing 10. Thus, multiple exhaust channels 142 can be formed through the sub-supports 1401, which can improve exhaust efficiency and enable the high-temperature gas on both sides of the electrode assembly 20 to be discharged quickly.

[0129] like Figure 9As shown, in some embodiments, on the third direction F3, the support 14 and the pressure relief mechanism 40 are arranged at intervals, and on the third direction F3, the shortest distance between the support 14 and the pressure relief mechanism 40 is x, which satisfies: 3mm≤x≤20mm.

[0130] If the distance between the support part 14 and the pressure relief mechanism 40 is too small, the support part 14 is prone to interference with the pressure relief mechanism 40, and local protrusions are easily formed during the manufacturing process, which can damage the electrode assembly 20. However, if the distance between the support part 14 and the pressure relief mechanism 40 is too large, the support part 14 and the pressure relief mechanism 40 cannot provide support for the electrode assembly 20, resulting in poor support for the electrode assembly 20 and easily affecting the exhaust channel.

[0131] Therefore, the shortest distance x between the support 14 and the pressure relief mechanism 40 is limited to between 3mm and 20mm. x can be any single value or a range between any two of the following: 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, and 20mm. This facilitates manufacturing, reduces deformation at the groove, minimizes local protrusions, and provides some support for the electrode assembly 20, reducing the probability of non-directional pressure relief due to internal pressure buildup and, to some extent, preventing an increase in burst pressure.

[0132] In some embodiments, the pressure relief mechanism 40 is provided with a plurality of exhaust channels 142 on any side of the third direction F3, and the plurality of exhaust channels 142 are arranged symmetrically with respect to the center of the first wall portion 11.

[0133] By setting multiple exhaust channels 142, the exhaust space is increased without affecting the support effect of the support part 14, thereby increasing the gas discharge speed. In addition, the exhaust channels 142 are symmetrically arranged, which makes the support effect of the support part 14 more uniform, and the high temperature gas at different positions can be discharged quickly and evenly through the exhaust channels 142 and the pressure relief mechanism 40.

[0134] like Figure 8 and Figure 13 As shown, in some embodiments, a support surface 141 is formed on the side of the support portion 14 near the electrode assembly 20, and the support surface 141 is a plane parallel to the surface of the first wall portion 11.

[0135] The top of the support portion 14 is a plane parallel to the surface of the first wall portion 11. The electrode assembly 20 is installed inside the housing 10. The electrode assembly 20 will not be tilted, so that there is an exhaust channel between the electrode assembly 20 and the first wall portion 11, thereby improving the flow efficiency of high temperature gas to the pressure relief mechanism 40. The high temperature gas can be quickly discharged to the outside of the battery cell 100 through the exhaust channel and the pressure relief mechanism 40.

[0136] In addition, the top of the support 14 is flat, which can reduce damage to the electrode assembly 20 caused by local protrusions and improve the reliability of the battery cell 100.

[0137] In some embodiments, the support portion 14 includes a plurality of sub-support portions 1401, the total area of ​​the support surface 141 of the plurality of sub-support portions 1401 is S1, and the area of ​​the first wall portion 11 is S2, satisfying: 0.3≤S1 / S2≤0.7.

[0138] like Figures 10-13 As shown, the dimension of the first wall portion 11 in the first direction F1 is the maximum dimension of the outer shell 10 in the first direction F1, the dimension of the first wall portion 11 in the third direction F3 is the maximum dimension of the outer shell 10 in the third direction F3, the width dimension of the first wall portion 11 in the first direction F1 is a, the length dimension of the first wall portion 11 in the third direction F3 is b, and the area of ​​the first wall portion 11 is S2 = a × b.

[0139] In a given battery cell of a certain size, the size of the first wall portion 11 is fixed. If S1 / S2 is too small and S1 is too small, the support portion 14 provides poor support for the electrode assembly 20, and the electrode assembly 20 is prone to sagging, encroaching on the exhaust space. This makes it difficult for high-temperature gas to flow to the pressure relief mechanism 40, which can easily lead to non-directional pressure relief caused by internal pressure buildup. If S1 / S2 is too large and S1 is too large, the support portion 14 occupies too much space, which reduces the space of the pressure relief mechanism 40. This can easily lead to the exhaust area of ​​the pressure relief mechanism 40 not meeting the pressure relief requirements.

[0140] Therefore, S1 / S2 is limited to the range of 0.3-0.7. S1 / S2 can be any point value among 0.3, 0.4, 0.5, 0.6, and 0.7, or a range between any two.

[0141] This not only enhances the supporting function of the support portion 14, providing a certain exhaust channel between the electrode assembly 20 and the first wall portion 11, but also meets the pressure relief requirements for the exhaust area, thereby improving the reliability of the battery cell 100.

[0142] To make the technical problems, technical solutions, and beneficial effects solved by the embodiments of this application clearer, the following will provide a more detailed description in conjunction with the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. 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.

[0143] Example 1

[0144] The battery cells use lithium iron phosphate batteries, and prismatic cells are selected to adjust the area of ​​the first wall (the first wall size is 71mm*275mm, corresponding to S2=19525mm²). 2 The area of ​​the support surface is changed by adjusting the size of the support part. An internal heating film is placed inside the battery cell, and the battery cell is subjected to thermal runaway testing. The thermal runaway test is as follows: a 40V voltage is applied to the internal heating film, and thermal runaway is triggered by 10A. The state of the weld seam is observed after the battery cell fails.

[0145] The cell preparation methods in Examples 2-14 are the same as in Example 1, except for the values ​​of S1 and / or S2. In Examples 8-14, the first wall dimension is 50mm*194mm, corresponding to S2=9700mm. 2 The specific batteries are shown in Table 1. The battery cells obtained in Examples 1-14 were characterized under thermal runaway conditions, and the characterization results are shown in Table 1.

[0146] Table 1

[0147]

[0148] Based on the data from embodiments 1-14, it can be seen that when S1 / S2 is between 0.3 and 0.7, the battery cell 100 can be depressurized in a directional manner. S1 / S2 can be adjusted within the range of 0.3-0.7, which can improve the supporting effect of the support part 14, provide a certain exhaust channel between the electrode assembly 20 and the first wall part 11, and meet the requirements of the exhaust area for depressurization, thereby improving the reliability of the battery cell 100.

[0149] In some embodiments, 0.4 ≤ S1 / S2 ≤ 0.7.

[0150] During vibration testing, if the area of ​​the support surface 141 is too small, the active material in the electrode assembly 20 may fall off. By limiting S1 / S2 to between 0.4 and 0.7, S1 / S2 can be any one of 0.4, 0.5, 0.6, or 0.7 or any range between two of them.

[0151] This can further enhance the supporting effect of the support part 14, provide a certain exhaust channel 12 between the electrode assembly 20 and the first wall part 11, reduce the probability of active material falling off the electrode assembly 20 during vibration testing, and meet the pressure relief requirements for exhaust area, thereby improving the reliability of the battery cell 100.

[0152] In some embodiments, the minimum size of the support surface 141 in the first direction F1 and the third direction F3 is w1, satisfying: 1.5mm≤w1≤4mm.

[0153] like Figures 10-13 As shown, the support portion 14 extends along the third direction F3, and correspondingly, the support surface 141 extends along the third direction F3. The dimension of the support surface 141 in the third direction F3 is c, and the dimension of the support surface 141 in the first direction F1 is d. The smaller value of c and d is w1.

[0154] If w1 is too small, the presence of the support surface 141 is similar to the presence of small particles or sharp materials inside the battery cell 100. During vibration and impact, it is easy to cause local stress on the electrode assembly 20, and the electrode assembly 20 is prone to metal precipitation. It is also easy to cause the active material in the electrode assembly 20 to fall off during vibration and impact. If w1 is too large, it is difficult to manufacture and form. Since the thickness of the first wall 11 is fixed, the thickness difference between the two is too large, and there is a risk of cracking during the manufacturing process.

[0155] Therefore, w1 is limited to the range of 1.5mm-4mm. w1 can be any point value of 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, or 4mm, or a range between any two.

[0156] This facilitates manufacturing and improves manufacturing yield, while also reducing the probability of localized stress on the electrode assembly 20 by the support portion 14, thereby improving the reliability of the battery cell 100.

[0157] like Figure 13 As shown, in some embodiments, the first wall portion 11 has a first inner surface 1101 and a first outer surface 1102. The first inner surface 1101 is closer to the electrode assembly 20 relative to the first outer surface 1102. The distance between the support surface 141 and the first inner surface 1101 in the second direction F2 is h1. The capacity of the battery cell 100 is C, which satisfies: 35 Ah / mm ≤ C / h1 ≤ 400 Ah / mm.

[0158] like Figure 13As shown, the maximum height of the support part 14 protruding from the inner surface of the first wall part 11 is h1. If C / h1 is too small and h1 is too large, the support part 14 will protrude too much, occupying internal space and sacrificing too much energy density. If C / h1 is too large and h1 is too small, the exhaust space will be too small and it will be difficult to meet the exhaust demand.

[0159] Therefore, C / h1 is limited to the range of 35 Ah / mm to 400 Ah / mm. C / h1 can be any one of the following values ​​or a range between any two: 35 Ah / mm, 100 Ah / mm, 150 Ah / mm, 200 Ah / mm, 250 Ah / mm, 300 Ah / mm, 350 Ah / mm, and 400 Ah / mm.

[0160] This satisfies both exhaust demand and energy density requirements, thus avoiding excessive reduction in energy density to some extent.

[0161] To make the technical problems, technical solutions, and beneficial effects solved by the embodiments of this application clearer, the following will provide a more detailed description in conjunction with the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. 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.

[0162] Example 15

[0163] The battery cells use lithium iron phosphate batteries, and the capacity C is changed by selecting prismatic cells of different sizes. The height h1 is changed by adjusting the height of the protruding support. An internal heating film is placed inside the battery cell. The battery cell is then subjected to thermal runaway testing. The thermal runaway test is performed by connecting the internal heating film to a 40V voltage and applying 10A to trigger thermal runaway, and observing the weld condition after the battery cell fails.

[0164] The battery cell preparation methods in Examples 16-18 are the same as those in Example 15, except that the values ​​of C and / or h1 are shown in Table 2. The battery cells obtained in Examples 15-18 were characterized under thermal runaway conditions, and the characterization results are shown in Table 2.

[0165] Table 2

[0166]

[0167] Based on the data from Examples 15-18, it can be seen that when C / h1 is less than 400, directional pressure relief can be achieved. C / h1 can be adjusted within the range of 35-400, which can meet both the exhaust demand and the energy density requirement, and avoid excessive reduction in energy density to a certain extent.

[0168] In some embodiments, the housing 10 is provided with an insulating member located between the support portion 14 and the electrode assembly 20, and the support surface 141 abuts against the insulating member to support the insulating member.

[0169] The insulating component can be a support plate located at the bottom of the electrode assembly 20. The insulating component can effectively isolate the direct contact between the electrode assembly 20 and the support part 14, prevent the bottom of the electrode assembly 20 from short-circuiting with the outer casing, thereby improving the reliability of the battery. At the same time, the support surface 141 directly abuts against the insulating component, realizing the supporting role of the support part 14 on the electrode assembly 20 and the insulating component, and improving the reliability of the support.

[0170] like Figure 4 As shown, in some embodiments, an insulating film 26 is provided on the outer periphery of the electrode assembly 20, and the support surface 141 abuts against the insulating film 26 to support the insulating film 26 and the electrode assembly 20.

[0171] The support surface 141 directly abuts against the insulating film 26, thereby enabling the support part 14 to support the electrode assembly 20. Moreover, the insulating film 26 can effectively isolate the direct contact between the electrode assembly 20 and the support part 14, preventing short circuits.

[0172] In some embodiments, the support portion 14 is integrally formed with the first wall portion 11 by a stamping process. This simplifies the manufacturing process of the support portion 14 and facilitates its production.

[0173] In some embodiments, the pressure relief mechanism 40 is integrally formed with the first wall portion 11.

[0174] By integrally molding the pressure relief mechanism 40 with the first wall portion 11, the reliability of the pressure relief mechanism 40 can be improved, the connection process between the pressure relief mechanism 40 and the first wall portion 11 can be eliminated, and the production cost of the battery cell 100 can be reduced.

[0175] In some embodiments, the groove 402 includes a first groove 41, a portion of the first wall portion 11 is punched toward the electrode assembly 20 to form the first groove 41, and another portion of the first wall portion 11 is punched toward the electrode assembly 20 to form a support portion 14, the support portion 14 being close to the electrode assembly 20 relative to the first groove 41.

[0176] Therefore, the height of the support portion 14 protruding from the inner surface of the first wall portion 11 is higher than that of the first groove 41. There is a certain exhaust channel 12 between the electrode assembly 20 and the first wall portion 11. The exhaust channel 12 extends along the third direction F3. The high-temperature gas between the electrode assembly 20 and the third wall portion 13 can be discharged to the pressure relief mechanism 40 through the exhaust channel 12, and then discharged through the pressure relief mechanism 40, reducing the probability of non-directional pressure relief caused by internal pressure buildup and improving the reliability of the battery cell 100.

[0177] In some embodiments, the pressure relief mechanism 40 is separately disposed from the first wall portion 11, the first wall portion 11 is provided with a pressure relief hole, and the pressure relief mechanism 40 is installed in the pressure relief hole.

[0178] The pressure relief mechanism 40 and the outer casing 10 are two separate components, which are molded separately and then installed together. Specifically, the pressure relief mechanism 40 can be a component such as an explosion-proof plate, an explosion-proof valve, or a safety valve. The pressure relief mechanism 40 can be installed on the first wall 11 by means of bonding, welding, etc. The first wall 11 is provided with a pressure relief hole, and the pressure relief mechanism 40 is installed in the pressure relief hole. When the internal pressure of the battery cell 100 reaches the threshold, the pressure relief mechanism 40 opens at least part of the pressure relief hole, and the discharge medium inside the battery cell 100 is discharged through the pressure relief hole to release the pressure inside the battery cell 100.

[0179] Taking the pressure relief mechanism 40 as an example, the explosion-proof sheet is a sheet with at least a portion of its strength being less than the strength of the first wall portion 11. The explosion-proof sheet covers the pressure relief hole and is welded to the first wall portion 11. When the internal pressure of the battery cell 100 reaches a threshold, the explosion-proof sheet is at least partially destroyed, thereby opening at least a portion of the pressure relief hole to release the internal pressure of the battery cell 100.

[0180] In this embodiment, the pressure relief mechanism 40 is a component independent of the outer casing 10. The pressure relief mechanism 40 and the outer casing 10 can be manufactured and reassembled separately, which is easy to produce and highly efficient.

[0181] like Figure 4 As shown, in some embodiments, the housing 10 includes a housing 101 and an end cap 102, the housing 101 having an opening at at least one end along the second direction F2, the end cap 102 being connected to the housing 101 and used to close the opening, and a first wall portion 11 being formed in the housing 101.

[0182] The housing 101 and the end cap 102 constitute the outer shell of the battery cell 100, that is, the outermost structural component of the battery cell 100. The housing contains the electrode assembly 20 and electrolyte, etc. The electrode assembly 20 contained therein can be one or more.

[0183] The shell 101 can be a hollow structure with an opening at one end, or it can be a hollow structure with openings at both opposite ends. The shell 101 can have various shapes, such as a prism, which can be a triangular prism, square prism, pentagonal prism, hexagonal prism, etc., and a square prism can be a cuboid, cube, etc. The first direction F1 is parallel to the orientation of the opening of the shell 101. In the embodiment where the shell 101 is prism-shaped, the first direction F1 can be parallel to the extension direction of the side edge of the shell 101, and the second direction F2 is parallel to the thickness direction of the first wall portion 11.

[0184] End cap 102 is a component that closes the opening of housing 101 to isolate the internal environment of battery cell 100 from the external environment. End cap 102 and housing 101 together define a receiving space for accommodating electrode assembly 20, electrolyte, and other components. The shape of end cap 102 can be adapted to the shape of housing; for example, housing 101 may be a cuboid structure, and end cap 102 may be a rectangular plate structure adapted to housing. End cap 102 can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The materials of end cap 102 and housing 101 can be the same or different.

[0185] In an embodiment where the housing 101 has an opening at one end, one end cap 102 may be provided. In an embodiment where the housing 101 has openings at both opposite ends, two end caps 102 may be provided. The two end caps 102 respectively close the two openings of the housing 101, and the two end caps 102 and the housing 101 together define a receiving space to accommodate the electrode assembly 20 and electrolyte, etc.

[0186] In an embodiment where the housing 101 has openings at opposite ends, two end caps 102 can be provided. The two end caps 102 respectively close the two openings of the housing 101. The two end caps 102 and the housing 101 together define a receiving space to accommodate the electrode assembly 20 and electrolyte, etc.

[0187] By setting the pressure relief mechanism 40 on the housing 101, the structure of the end cover 102 can be simplified, and the distance between the pressure relief mechanism 40 and the main body of the electrode assembly 20 can be shortened. This shortens the path of the discharge medium to the pressure relief mechanism 40 during pressure relief, reduces the time it takes for the discharge medium to reach the pressure relief mechanism 40, improves the timeliness of pressure relief of the battery cell 100, and thus effectively improves the reliability of the battery cell 100.

[0188] like Figure 3 and Figure 4 As shown, in some embodiments, the first wall portion 11 is used to support the electrode assembly 20 and is located below the electrode assembly 20.

[0189] Therefore, the pressure relief mechanism 40 can be located at the bottom of the battery cell 100. The bottom of the battery cell 100 can be provided with an exhaust channel, which can be connected to the pressure relief mechanism 40. In the event of thermal runaway of the battery cell 100, the high-temperature and high-pressure flue gas can be discharged through the pressure relief mechanism 40 at the bottom into the exhaust channel and then discharged to the outside.

[0190] The battery 1000 according to the second aspect embodiment of this application includes the battery cell 100 according to the first aspect embodiment of this application. Therefore, by using the battery cell 100, the reliability of the battery 1000 is improved.

[0191] The electrical device 2000 according to a third aspect embodiment of this application includes a battery 1000 according to the second aspect embodiment of this application described above. The battery 1000 is used to provide electrical energy to the electrical device 2000. Therefore, by using the battery 1000 described above, it is beneficial to improve the safety and reliability of the electrical device 2000.

[0192] Optionally, such as Figure 1 As shown, when the battery 1000 is used in a vehicle, it can be located at the bottom, front, or rear of the vehicle. The battery 1000 can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. The vehicle may also include a controller and a motor. The controller controls the battery 1000 to power the motor, for example, to meet the vehicle's power needs during starting, navigation, and driving.

[0193] The following description, in conjunction with the accompanying drawings, describes a specific embodiment of a battery 1000 and a vehicle having the same.

[0194] like Figure 1 As shown, battery 1000 is located at the bottom of the vehicle, and as... Figure 2 As shown, the battery 1000 includes multiple battery cells 100, such as Figure 4 As shown, each battery cell 100 includes a housing 10 and two electrode assemblies 20. The housing 10 is provided with an electrical connection part 30 and a pressure relief mechanism 40, which are located on different sides of the housing 10. The electrode assemblies 20 are arranged inside the housing 10.

[0195] The housing 10 has a first wall portion 11 and two second walls portion 12. The first wall portion 11 is located on one side of the electrode assembly 20 in the second direction F2, and the two second walls portion 12 are located on both sides of the electrode assembly 20 in the first direction F1. The first wall portion 11 has a first outer surface 1102 and a first inner surface 1101. The first inner surface 1101 is closer to the electrode assembly 20 relative to the first outer surface 1102.

[0196] like Figures 7-13As shown, a support portion 14 and a groove 402 are integrally stamped on the first wall portion 11 by a stamping process. The support portion 14 includes a plurality of sub-support portions 1401, which are symmetrically arranged on both sides of the pressure relief mechanism 40. An exhaust channel 142 is formed between two adjacent sub-support portions 1401, and an exhaust channel 142 is formed between the sub-support portion 1401 and the second wall portion 12.

[0197] The groove 402 includes a first groove 41 and a second groove 42. The first groove 41 and the support portion 14 are both formed by recessing from the first outer surface 1102 of the first wall portion 11 towards the first inner surface 1101. The second groove 42 is formed by recessing from the first inner surface 1101 of the first wall portion 11 towards the first outer surface 1102. The residual thickness at the first groove 41 is less than the residual thickness at the second groove 42.

[0198] Each sub-support 1401 extends along the third direction F3, and the sub-support 1401 is spaced apart from the pressure relief mechanism 40. The shortest distance between the sub-support 1401 and the first groove 41 is x, where x is 5.5 mm.

[0199] An insulating film 26 is provided on the outside of the electrode assembly 20. The insulating film 26 covers a part of the electrode assembly 20, so that the electrode assembly 20 is insulated from the outer shell 10. An insulating member is also provided between the electrode assembly 20 and the first wall portion 11. The insulating member is supported on the support portion 14. The exhaust channel 142 is located between the insulating member and the first wall portion 11.

[0200] 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 (100) characterized by, include: An electrode assembly (20) includes at least one positive electrode (21), at least one negative electrode (22), and at least one separator (25), the separator (25) being used to isolate the positive electrode (21) and the negative electrode (22). The electrode assembly (20) includes a flat region (23), at least a portion of the positive electrode (21), at least a portion of the negative electrode (22), and at least a portion of the separator (25) being stacked in the flat region (23) along a first direction. A housing (10) for accommodating the electrode assembly (20), the housing (10) including a first wall (11) located on one side of the electrode assembly (20) in a second direction; A pressure relief mechanism (40) is disposed on the first wall portion (11), and the pressure relief mechanism (40) is at least partially capable of opening when the battery cell (100) is depressurized; The first wall portion (11) is provided with a support portion (14), at least a portion of which is located on the side of the first wall portion (11) near the electrode assembly (20). The support portion (14) is located on at least one side of the pressure relief mechanism (40) in the third direction and forms an exhaust channel (142). The exhaust channel (142) is provided to penetrate the support portion (14) along the third direction. The third direction, the second direction and the first direction of the first wall portion (11) are perpendicular to each other.

2. The battery cell (100) according to claim 1, characterized in that The support (14) includes a plurality of sub-supports (1401), which are symmetrically arranged on both sides of the pressure relief mechanism (40) in the third direction.

3. The battery cell (100) according to claim 2, characterized in that The plurality of said sub-supports (1401) are arranged symmetrically with respect to the center of the first wall portion (11) in the first direction.

4. The battery cell (100) according to claim 2, characterized in that The plurality of sub-support portions (1401) are arranged at intervals in the first direction, and the exhaust passage (142) is formed between two adjacent sub-support portions; and / or, the exhaust passage (142) is formed between the sub-support portion (1401) and other wall portions of the housing (10).

5. The battery cell (100) of claim 2, wherein, In the third direction, the support part (14) and the pressure relief mechanism (40) are arranged at intervals, and in the third direction, the shortest distance between the support part (14) and the pressure relief mechanism (40) is x, which satisfies: 3mm≤x≤20mm.

6. The battery cell (100) of claim 1, wherein, The pressure relief mechanism (40) has a plurality of exhaust channels (142) on any side in the third direction, and the plurality of exhaust channels (142) are arranged symmetrically with respect to the center of the first wall portion (11).

7. The battery cell (100) of claim 1, wherein, A support surface (141) is formed on the side of the support portion (14) near the electrode assembly (20), and the support surface (141) is a plane parallel to the surface of the first wall portion (11).

8. The battery cell (100) according to claim 7, characterized in that The support part (14) includes a plurality of sub-support parts (1401), the total area of ​​the support surface (141) of the plurality of sub-support parts (1401) is S1, and the area of ​​the first wall part (11) is S2, satisfying: 0.3≤S1 / S2≤0.

7.

9. The battery cell (100) according to claim 8, characterized in that 0.4≤S1 / S2≤0.

7.

10. The battery cell (100) of claim 7, wherein, The minimum dimension of the support surface (141) in the first direction and the third direction is w1, which satisfies: 1.5mm≤w1≤4mm.

11. The battery cell (100) of claim 7, wherein, The first wall portion (11) has a first inner surface (1101) and a first outer surface (1102), the first inner surface (1101) is closer to the electrode assembly (20) relative to the first outer surface (1102), the distance between the support surface (141) and the first inner surface (1101) in the second direction is h1, and the capacity of the battery cell (100) is C, satisfying: 35 Ah / mm≤C / h1≤400 Ah / mm.

12. The battery cell (100) according to claim 7, characterized in that, An insulating element is provided inside the housing (10). The insulating element is located between the support portion (14) and the electrode assembly (20). The support surface (141) abuts against the insulating element to support the insulating element.

13. The battery cell (100) according to claim 7, characterized in that, An insulating film (26) is provided on the outer periphery of the electrode assembly (20), and the support surface (141) abuts against the insulating film (26) to support the insulating film (26) and the electrode assembly (20).

14. The battery cell (100) of claim 1, wherein, The support portion (14) is integrally formed with the first wall portion (11).

15. The battery cell (100) according to claim 14, characterized in that The pressure relief mechanism (40) is integrally formed with the first wall portion (11).

16. The battery cell (100) according to claim 15, characterized in that The pressure relief mechanism (40) is provided with a groove (402), the groove (402) includes a first groove (41), a portion of the first wall (11) is punched toward the electrode assembly (20) to form the first groove (41), and another portion of the first wall (11) is punched toward the electrode assembly (20) to form the support portion (14), the height of the support portion (14) protruding from the first wall (11) is greater than the height of the first groove (41) protruding from the first wall (11).

17. The battery cell (100) according to claim 1, characterized in that, The pressure relief mechanism (40) is separately disposed from the first wall portion (11), the first wall portion (11) is provided with a pressure relief hole, and the pressure relief mechanism (40) is installed in the pressure relief hole.

18. The battery cell (100) of claim 1, wherein, The outer casing (10) includes a housing (101) and an end cap (102), wherein the housing (101) has an opening at at least one end along a second direction, the end cap (102) is connected to the housing (101) and is used to close the opening, and the first wall portion (11) is formed in the housing (101).

19. The battery cell (100) according to any one of claims 1-18, characterized in that, The first wall portion (11) is used to support the electrode assembly (20) and is located below the electrode assembly (20).

20. A battery, characterized by Includes the battery cell (100) according to any one of claims 1-19.

21. An electrical device, comprising: Includes the battery according to claim 20, the battery being used to provide electrical energy to the electrical device.

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