Battery cells, batteries and power consuming devices

Abstract

An embodiment of the present application provides a battery cell, a battery, and an energy-consuming device, which includes an outer casing including a first wall and a pressure-reducing mechanism installed on the first wall, wherein the rupture pressure of the pressure-reducing mechanism is P1 and the rupture pressure of the outer casing is P2, where P2 ≥ 1.7 MPa and P2 > P1 are satisfied. In the technical solution of the present application, the rupture pressure P2 of the outer casing is designed to be 1.7 MPa or more, which can significantly improve the pressure resistance of the outer casing. This design effectively improves the stability of the battery cell in directional pressure release from the pressure-reducing mechanism, while also reducing the risk of the outer casing bursting due to pressure release from the pressure-reducing mechanism, effectively improving the structural stability and safety of the battery cell.

Description

[Technical Field]

[0001] This application relates to the field of battery technology, and more particularly to battery cells, batteries, and power consuming devices. [Background technology]

[0002] With energy conservation and emission reduction being key points in the sustainable development of the automotive industry, electric vehicles have become an important component in the sustainable development of the automotive industry due to their energy-saving and environmentally friendly advantages. Battery technology is a key element in the development of electric vehicles and energy storage systems.

[0003] With the advancement of battery technology, how to improve the structural stability and safety of batteries is a technical issue that must be resolved as soon as possible. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application provides a battery cell, a battery, and a power consumption device that can efficiently improve the structural stability and safety thereof.

[0005] According to a first aspect, the present application provides a battery cell including an outer case including a first wall and a pressure reducing mechanism installed on the first wall, wherein the burst pressure of the pressure reducing mechanism is P1, the burst pressure of the outer case is P2, and P2≧1.7MPa, P2>P1. [Means for solving the problem]

[0006] In the technical solution of the present application, a pressure reduction mechanism is installed on the outer casing of the battery cell, and when thermal runaway occurs in the battery cell, the energy released and the resulting waste can be released through the pressure reduction mechanism. However, with the increase in energy density of battery systems, the runaway output when thermal runaway occurs in the battery cell increases significantly. The energy released and the resulting waste are released in a very short time. If the outer casing of the battery cell does not have sufficient pressure resistance, the waste will be released from areas other than the pressure reduction mechanism, causing serious damage to the outer casing and irregular release of waste, affecting the structural stability and safety of the battery. Furthermore, pressure release from areas other than the pressure reduction mechanism of the battery cell is likely to cause the battery system's multiple protection functions to be invalid, posing a greater safety risk. In the technical solution of the present application, the burst pressure P2 of the outer casing of the battery cell is greater than the burst pressure P1 of the pressure reducing mechanism. At the same time, the burst pressure P2 of the outer casing is designed to be 1.7 MPa or more, which significantly improves the pressure resistance of the outer casing. This design effectively improves the stability of the battery cell's directional pressure release from the pressure reducing mechanism, while also reducing the risk of the outer casing bursting when the pressure reducing mechanism releases pressure, effectively improving the structural stability and safety of the battery cell.

[0007] According to some embodiments of the present application, P2 / P1≧1.35.

[0008] In the above technical solution, the ratio of the outer casing's burst pressure P2 to the pressure reducing mechanism's burst pressure P1 is 1.35 or greater. If the ratio of P2 to P1 is too small (i.e., P1 approaches P2), the battery cell may experience thermal runaway. After the pressure reducing mechanism is activated, the outer casing is likely to burst immediately after the pressure reducing mechanism bursts, resulting in the battery failing. Designing the ratio of P2 to P1 to be 1.35 or greater ensures a certain safety margin between the pressure reducing mechanism's pressure and the outer casing's withstand pressure, thereby improving the likelihood that the pressure reducing mechanism will burst before the outer casing and further reducing the risk of the outer casing bursting and failing due to the pressure reducing mechanism, effectively improving the structural stability and safety of the battery cell.

[0009] According to some embodiments of the present application, P2-P1≧0.4 MPa.

[0010] In the above technical solution, the difference between the burst pressure P2 of the outer casing and the burst pressure P1 of the pressure reducing mechanism is 0.4 MPa or more. If the difference between P2 and P1 is too small (i.e., P1 approaches P2), the battery cell may experience thermal runaway. After the pressure reducing mechanism is activated, the outer casing is likely to burst immediately after the pressure reducing mechanism bursts, resulting in the battery failing. Designing the difference between P2 and P1 to be 0.4 MPa or more further ensures a safety margin between the pressure reducing mechanism pressure and the withstand pressure of the outer casing, improving the reliability of the pressure reducing mechanism bursting before the outer casing and further reducing the risk of the outer casing bursting and failing due to the pressure reducing mechanism, effectively improving the structural stability and safety of the battery cell.

[0011] According to some embodiments of the present application, 0.5 MPa≦P1≦1.3 MPa.

[0012] In the above technical solution, the burst pressure P1 of the pressure reducing mechanism is designed to be between 0.5MPa and 1.3MPa. If P1 is set too small, the pressure reducing mechanism of the battery cell is likely to activate prematurely during normal use, affecting the service life of the battery cell. If P1 is set too large, the requirements for the pressure resistance strength of the outer casing are too high and the pressure release needs of the battery cell cannot be met. By designing P1 to be between 0.5MPa and 1.3MPa, the pressure release needs of the battery cell can be effectively met.

[0013] According to some embodiments of the present application, the outer case includes a housing and an end cover, the housing having an opening and the end cover sealing the opening.

[0014] In the above technical solution, the outer case includes a housing and an end cover, and the split structure of the outer case facilitates modularization of the battery cells. The burst pressure of the areas of the outer case other than the pressure-reducing mechanism (including the end cover itself, the housing itself, and the connection between the housing and the end cover) is designed to be 1.7 MPa or more, which effectively ensures the connection stability between the housing and the end cover when thermal runaway occurs in the battery cells, and the pressure resistance stability of the entire outer case.

[0015] According to some embodiments of the present application, the end cover is a rectangular plate, and the width of the end cover is W, which satisfies W≦40 mm.

[0016] In the above technical solution, the wider the end cover, the less deformation resistance the end cover has, and the more likely it is to deform under force when thermal runaway occurs in the battery cells. The deformation of the end cover directly affects the stability of the connection between the end cover and the housing, thereby reducing the pressure resistance of the connection between the end cover and the housing. By designing the width of the end cover to be 40 mm or less, the deformation resistance of the end cover can be effectively guaranteed, thereby effectively improving the pressure resistance of the connection between the housing and the end cover.

[0017] According to some embodiments of the present application, the end cover is a rectangular plate, and the length of the end cover is L, which satisfies L≦1200 mm.

[0018] In the above technical solution, the longer the end cover is, the less deformation resistance the end cover has, and the more likely it is to deform under force when thermal runaway occurs in the battery cells. The deformation of the end cover directly affects the stability of the connection between the end cover and the housing, thereby reducing the pressure resistance of the connection between the end cover and the housing. By designing the length of the end cover to be 1200 mm or less, the deformation resistance of the end cover can be effectively guaranteed, thereby effectively improving the pressure resistance of the connection between the housing and the end cover.

[0019] According to some embodiments of the present application, the thickness of the end cover is H1, satisfying 1 mm ≤ H1 ≤ 5 mm.

[0020] In the above technical solution, the minimum thickness of the end cover is 1 mm or more, which can effectively improve the anti-deformation performance of the end cover itself, thereby effectively improving the pressure resistance strength of the connection part between the end cover and the housing. The maximum thickness of the end cover is 5 mm or less, which can guarantee the anti-deformation performance of the end cover itself and at the same time reduce the space occupancy rate of the end cover, contributing to the improvement of the energy density of the battery cell and the reduction of the overall weight of the battery cell.

[0021] According to some embodiments of the present application, the end cover is the wall with the maximum thickness of the outer case.

[0022] In the above technical solution, the end cover is the wall with the maximum thickness of the outer case. In the process of modularizing the battery cell, the end cover generally needs to be connected to the housing by means such as welding, crimping, winding, etc. At the same time, assemblies such as pole terminals are often attached to the end cover. The thickness of the end cover increases, which can effectively guarantee the structural strength of the end cover, thereby reducing the risk of the end cover deforming under force.

[0023] According to some embodiments of the present application, the wall thickness of the housing is H2, satisfying 0.2 mm < H2 ≤ 3 mm.

[0024] In the above technical solution, the minimum thickness of each wall part of the housing is greater than 0.2 mm, which can effectively improve the anti-deformation performance of the housing, thereby effectively improving the pressure resistance strength of the connection part between the end cover and the housing and the overall pressure resistance strength of the housing. The thickness of the housing is 3 mm or less, which can guarantee the anti-deformation performance of the housing and at the same time reduce the space occupancy rate of the housing, contributing to the improvement of the energy density of the battery cell and the reduction of the overall weight of the battery cell.

[0025] According to some embodiments of the present application, the first wall is an end cover.

[0026] In the above technical solution, the pressure reducing mechanism may be installed in the end cover, which is useful for the production and assembly of the battery cell. When the battery cell experiences thermal runaway, the gas inside the outer case flows toward the pressure reducing mechanism, and the end cover and the connection between the end cover and the housing are subjected to great pressure. However, by designing the burst pressure value of the entire outer case to be 1.7 MPa or more, the pressure resistance of the connection between the end cover and the housing can be effectively guaranteed, thereby effectively improving the structural stability and safety of the outer case.

[0027] According to some embodiments of the present application, the end cover is welded to the housing, and the effective penetration depth of the weld between the end cover and the housing is D, which satisfies D≧200 μm.

[0028] In the above technical solution, the end cover is welded to the housing, which effectively ensures the connection stability between the end cover and the housing, thereby effectively improving the pressure resistance of the connection between the end cover and the housing. The effective penetration depth of the end cover is 200 μm or more, which can further improve the pressure resistance of the connection between the end cover and the housing, thereby improving the pressure resistance of the outer case.

[0029] According to some embodiments of the present application, D≦2000 μm is satisfied.

[0030] In the above technical solution, the effective penetration depth of the weld between the end cover and the housing is designed to be 2000 μm or less, which avoids the problem of the end cover being too thick due to excessive penetration depth requirements, and prevents the end cover from being too thick and affecting the energy density of the battery cell.

[0031] According to some embodiments of the present application, the volumetric energy density of the battery cell is T1, and T1≧600 Wh / L.

[0032] In the above technical solution, the burst pressure P2 of the outer casing is designed to be 1.7 MPa or more, and is applicable to high-energy density battery cells with a volumetric energy density of 600 Wh / L or more. The burst pressure P2 of the outer casing is 1.7 MPa or more, which effectively reduces the risk of high-temperature, high-pressure gas generated by the large amount of energy released when a high-energy density battery cell experiences thermal runaway breaking through areas other than the pressure-reducing mechanism of the outer casing.

[0033] According to some embodiments of the present application, T1≦1200 Wh / L is satisfied.

[0034] In the above technical solution, the outer case with a burst pressure of 1.7 MPa or more is applied to the battery cell with a volumetric energy density of 1200 Wh / L or less, which can further effectively improve the structural stability of the battery cell.

[0035] According to some embodiments of the present application, the weight energy density of the battery cell is T2, and T2≧220Wh / Kg.

[0036] In the above technical solution, the burst pressure P2 of the outer casing is designed to be 1.7 MPa or more, and is applicable to high-energy density battery cells with a weight energy density of 220 Wh / Kg or more. The burst pressure P2 of the outer casing is 1.7 MPa or more, which effectively reduces the risk of high-temperature, high-pressure gas generated by the large amount of energy released when a high-energy density battery cell experiences thermal runaway breaking through areas other than the pressure-reducing mechanism of the outer casing.

[0037] According to some embodiments of the present application, T2≦500Wh / Kg is satisfied.

[0038] In the above technical solution, the outer case with a burst pressure of 1.7 MPa or more is applied to the battery cell with a volumetric energy density of 500 Wh / Kg or less, which can further effectively improve the structural stability of the battery cell.

[0039] According to some embodiments of the present application, the outer case is a metal member.

[0040] In the above technical solution, the outer case is a metal component, and a metal outer case has higher structural rigidity, outstanding deformation resistance, and excellent heat resistance compared to outer cases made of plastic or other materials, which can further improve the structural stability of the battery cell.

[0041] According to a second aspect, the present application provides a battery including a housing and a battery cell according to any one of the above solutions installed in the housing.

[0042] Since the battery cell according to the first aspect of the present application has high structural stability and safety, the battery according to the second aspect of the present application also has high structural stability and safety.

[0043] According to a third aspect, the present application provides a power consuming device including a battery cell according to any of the above solutions for supplying electrical energy thereto. [Brief explanation of the drawings]

[0044] In order to more clearly describe the technical solutions in the embodiments of the present application, the following briefly describes the drawings required for the embodiments of the present application. It should be understood that the drawings shown below are only some embodiments of the present application, and those skilled in the art can further obtain other drawings based on the drawings without any creative efforts. [Figure 1] 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Figure 2] FIG. 1 is an exploded view of a battery according to some embodiments of the present application. [Figure 3] FIG. 1 is an exploded view of a battery cell according to some embodiments of the present application. [Figure 4] FIG. 10 is an exploded perspective view of a battery cell according to another embodiment of the present application. [Figure 5] 1 is a structural schematic diagram of an end cover according to some embodiments of the present application. [Figure 6] 1 is a structural schematic diagram of a housing according to some embodiments of the present application. [Figure 7] FIG. 7 is a partial enlarged view of part A shown in FIG. [Figure 8] FIG. 10 is a partial cross-sectional view of the end cover and the housing welded together. DETAILED DESCRIPTION OF THE INVENTION

[0045] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. The components of the embodiments of the present application described and shown in the drawings of this specification can generally be arranged and designed in various different configurations. It should be noted that the drawings are not drawn to scale.

[0046] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only illustrates selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0047] The following detailed description will be given of the embodiments of the technical solution of the present application with reference to the drawings. The following embodiments are only used to more clearly explain the technical solution of the present application, and are merely examples, which do not limit the scope of protection of the present application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs, and the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The terms "including" and "having" and their variants in the specification and claims of this application, as well as the description of the drawings above, are intended to be non-exclusive.

[0049] In the description of the embodiments of the present application, the terms "first," "second," etc. are merely used to distinguish between different objects, and should not be understood as indicating or implying relative importance, or the quantity, specific order, or hierarchical relationship of the technical features shown. In the description of the embodiments of the present application, unless otherwise clearly limited, "plurality" means two or more.

[0050] References to "an embodiment" herein mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. Appearances of the term "embodiment" in various places in this specification do not necessarily refer to the same embodiment, nor do they refer to embodiments that are mutually exclusive, independent, or alternative to other embodiments. Those skilled in the art will understand, both explicitly and implicitly, that the embodiments described herein can be combined with other embodiments.

[0051] In describing the embodiments of the present application, the term "plurality" refers to two or more (including two).

[0052] In describing the embodiments of the present application, the orientations or positional relationships indicated by terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" are based on the orientations or positional relationships shown in the drawings and are intended to make the embodiments of the present application easier to explain and simplify the description, and do not indicate or imply that the target devices or elements have a specific orientation or should be configured or operated in a specific orientation, and therefore should not be understood to limit the embodiments of the present application.

[0053] In describing the embodiments of the present application, unless otherwise clearly specified or limited, terms such as "installed," "attached," "connected," "connected," and "fixed" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection. They may also refer to a mechanical connection, an electrical connection, or a signal connection. They may also refer to a direct connection, an indirect connection via an intermediate medium, internal communication between two elements, or an interactive relationship between two parts. Those skilled in the art will be able to understand the specific meanings of the above terms in the embodiments of the present application according to specific circumstances.

[0054] In the embodiments of the present application, the same reference numerals indicate the same elements, and detailed descriptions of the same elements will be omitted in different embodiments for the sake of brevity. Note that the dimensions such as thickness, length, and width of each element in the embodiments of the present application and the overall dimensions such as thickness, length, and width of the integrated device shown in the drawings are merely illustrative and do not limit the present application in any way.

[0055] In the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium-sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, etc., but the embodiments of the present application are not limited thereto. The battery cell has a cylindrical shape.

[0056] The battery referred to in the embodiments of this application refers to a single physical module containing multiple battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module, a battery pack, or an energy storage device (such as a home energy storage system, an energy storage cabinet, or an energy storage container). Multiple battery cells may be directly connected in series, parallel, or series-parallel to form a battery. A series-parallel connection refers to multiple battery cells being connected in series as well as parallel. Multiple battery cells may first be connected in series, parallel, or series-parallel to form a battery cell module, and multiple battery cell modules may then be further connected in series, parallel, or series-parallel to form a battery. The battery may further include a housing for packaging one or more battery cells. The housing can prevent liquids or other foreign objects from affecting the charging and discharging of the battery cells.

[0057] The battery cell includes an outer case, an electrode assembly, and an electrolyte. The electrode assembly and the electrolyte are disposed in the outer case of the battery, and the outer case provides a space for accommodating the electrode assembly and the electrolyte.

[0058] The battery cell further includes a pressure reducing mechanism, which is an element or component that releases pressure or temperature inside the battery cell. The pressure reducing mechanism can take the form of an explosion-proof valve, an air valve, a pressure reducing valve, a safety valve, a shallow groove provided in the outer case, or the like.

[0059] Improving the structural stability and safety of batteries is currently an important goal in the development of the battery industry, and the inventors have noticed that when thermal runaway occurs in a battery cell, the structure and assembly of the battery are likely to be destroyed over a large area, easily causing a safety accident.

[0060] The inventors analyzed the causes and found that as the energy density of battery systems improves, the runaway energy generated when thermal runaway occurs in battery cells increases significantly, and that the energy and waste generated by thermal runaway are released in an extremely short time. The waste generated by runaway is likely to damage areas of the outer casing that are weak, such as thin areas or the connections between the outer casing walls, and that the waste generated by runaway is discharged from areas other than the pressure-reducing mechanism. The main causes of damage to the outer casing include: (1) When thermal runaway occurs, high-pressure waste generated by runaway easily penetrates and damages the outer casing; (2) After thermal runaway occurs, the outer casing is easily melted by high-temperature waste generated by runaway. Furthermore, destruction of the outer casing is likely to cause battery failure and safety risks. (1) Components such as the electrode assembly inside the outer casing are thrown out disorderly from the broken opening in the outer casing, causing the battery system to fail. (2) The destruction of the outer casing structure may cause the position of assemblies such as the bus components of the battery system to change, resulting in a short circuit of the high-voltage electrical connections. At the same time, some of the emissions from the runaway may be ejected directly onto parts of the battery, damaging the components and causing the battery system to fail, seriously affecting the structural stability and safety of the battery.

[0061] Based on these causes, when a battery cell experiences thermal runaway, high-pressure discharged material from the runaway may penetrate areas other than the pressure reduction mechanism of the outer case, causing damage to the outer case and affecting the structural stability and safety of the battery. To solve this problem, the inventors of the present application conducted extensive research and testing and designed a battery cell that includes an outer case and a pressure reduction mechanism installed in the outer case, where the burst pressure of the pressure reduction mechanism is P1 and the burst pressure of the outer case is P2, where P2≧1.7MPa and P2>P1.

[0062] In the technical solution of the present application, the burst pressure P2 of the outer casing is designed to be 1.7 MPa or more, which significantly improves the pressure resistance of the outer casing. This design effectively improves the stability of the battery cell's directional pressure release from the pressure reduction mechanism, while reducing the risk of the outer casing bursting when the pressure reduction mechanism releases pressure, effectively improving the structural stability and safety of the battery cell.

[0063] The batteries disclosed in the embodiments of the present application can be used in power consuming devices such as, but not limited to, vehicles, ships, power grids, or aircraft, and the batteries disclosed in the present application can be used to form the power supply system of the power consuming devices.

[0064] An embodiment of the present application provides a battery-powered power consumption device, which may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric vehicle, a boat, a spacecraft, etc. The electric toy may include a stationary or mobile electric toy such as a game console, an electric toy car, an electric toy boat, and an electric toy aircraft, and the spacecraft may include an aircraft, a rocket, a space shuttle, a spaceship, etc.

[0065] The battery described in the embodiments of the present application is not only applicable to the power consumption devices described above, but also to all power consumption devices that use batteries. However, for the sake of simplicity, the following embodiment will describe one embodiment of the power consumption device of the present application using a vehicle as an example.

[0066] Referring to FIG. 1, FIG. 1 is a structural schematic diagram of a vehicle 1000 according to some embodiments of the present application. The vehicle 1000 may be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, a range-extender vehicle, etc. A battery 100 is provided inside the vehicle 1000, and may be provided at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the operating power needs for starting, navigation, and driving the vehicle 1000.

[0067] In other embodiments, the battery 100 can provide not only the operating power source for the vehicle 1000 but also the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0068] 2, which shows an exploded view of a battery 100 according to some embodiments of the present application, the battery 100 includes a plurality of battery cells 10 and a housing 20, and the plurality of battery cells 10 are arranged in the housing 20. The housing 20 includes a first portion 21 and a second portion 22, and the first portion 21 and the second portion 22 are fitted together to form a receiving cavity, and the plurality of battery cells 10 are disposed in the battery cavity. The shapes of the first portion 21 and the second portion 22 may be determined by the combined shape of the plurality of battery modules, and each of the first portion 21 and the second portion 22 may have an opening. For example, the first part 21 and the second part 22 may both be hollow rectangular parallelepipeds with only one open side, the openings of the first part 21 and the second part 22 being arranged opposite each other, and the first part 21 and the second part 22 engaging with each other to form the housing 20 with a sealed storage cavity; alternatively, the second part 22 may be hollow rectangular parallelepipeds with only one open side, the first part 21 being plate-shaped, and engaging with the open side of the second part 22 to form the housing 20 with a sealed cavity, and multiple battery cells 10 are combined with each other in parallel connection, series connection, or series-parallel connection, and then placed in the housing 20 formed by engaging the first part 21 and the second part 22.

[0069] According to some embodiments of the present application, reference is made to Fig. 3, which is an exploded view of a battery cell 10 according to some embodiments of the present application. Some embodiments of the present application provide a battery cell 10 including an outer case 11 including a first wall and a pressure reducing mechanism 12 installed on the first wall. The burst pressure of the pressure reducing mechanism 12 is P1, and the burst pressure of the outer case 11 is P2, where P2 ≥ 1.7 MPa and P2 > P1 are satisfied.

[0070] The outer case 11 is used to house the electrode assembly 13, and may have various shapes, such as a cylinder or a rectangular parallelepiped. The outer case 11 may be made of an aluminum case, a steel case, an aluminum alloy case, or the like. The pressure reducing mechanism 12 is installed in a first wall of the outer case 11, and the first wall may be any one of the walls of the outer case 11.

[0071] 3, the outer case 11 may have a hexahedral structure, and may include a second wall adjacent to a first wall, the second wall being the wall with the largest area of ​​the outer case 11, and the area of ​​the first wall may be smaller than the area of ​​the second wall. That is, the pressure reducing mechanism 12 may be installed in the wall with the smallest area of ​​the outer case 11.

[0072] As described above, the pressure reducing mechanism 12 is an element or component that releases the internal pressure or temperature of the battery cell 10, and the pressure reducing mechanism 12 can take the form of an explosion-proof valve, an air valve, a pressure reducing valve, a safety valve, a shallow groove provided in the outer case 11, or the like. For example, if the pressure reducing mechanism 12 has a weak part, when the internal pressure of the battery cell 10 reaches a threshold value, the weak part provided in the pressure reducing mechanism 12 breaks, thereby forming an opening or flow path that can release the internal pressure or temperature of the battery cell 10, and the internal pressure of the battery cell 10 is released.

[0073] The burst pressure P1 of the pressure reducing mechanism 12 is the maximum pressure value inside the outer case 11 that is received when the fragile portion of the pressure reducing mechanism 12 bursts.

[0074] The burst pressure P2 of the outer case 11 is the maximum pressure value inside the outer case 11 that is received when the area of ​​the outer case 11 other than the pressure reducing mechanism 12 bursts.

[0075] P2 may be any value equal to or greater than 1.7 MPa, such as 1.7 MPa, 1.8 MPa, 1.9 MPa, 2.0 MPa, 2.5 MPa, or 3 MPa.

[0076] P1 and P2 of the battery cell 10 can be obtained by the following measurement method.

[0077] (1) The battery cell 10 is restrained using a structure such as a jig, and the stress state is made as equivalent as possible to the state of the battery cell 10 within the battery system.

[0078] (2) Use a tool such as a drill to make an opening on the surface of the outer case 11 of the battery cell 10 (if the outer case 11 includes a housing 111 and an end cover 112, the opening may be made in the end cover 112), insert the gas pipe into the inside of the battery cell 10 through the opening, and use structural adhesive or other sealing material to seal the gas pipe and the outer case 11, ensuring a good seal between the gas pipe and the outer case 11 and preventing gas leakage.

[0079] (3) Pressurize the inside of the outer case 11 through the gas pipe, adjust the flow valve to control the pressurization speed, and gradually fill the inside of the outer case 11 with gas until a weak part of the outer case 11 or the pressure reduction mechanism 12 is destroyed. Record the pressure value at that time, and if the location of the rupture is an area other than the pressure reduction mechanism of the outer case 11, the pressure value is taken as the rupture pressure value P2 of the outer case 11, and if the location of the rupture is a weak part of the pressure reduction mechanism 12, the pressure value is taken as the rupture pressure value P1 of the pressure reduction mechanism 12.

[0080] (4) If the area that ruptured first is a weak part of the pressure reduction mechanism 12, the pressure reduction mechanism 12 is resealed or sealed using a material such as a metal piece or structural adhesive (for example, a metal piece is welded to the outer case 11 so that the metal piece completely covers the pressure reduction mechanism 12 and seals the pressure reduction mechanism 12).

[0081] (5) Continue pressurizing the inside of the outer case 11 through the gas pipe, adjust the flow valve to control the pressurization speed, and continue filling the inside of the outer case 11 with gas until the outer case 11 bursts. Record the pressure value at that time, which is the burst pressure value P2 of the outer case 11.

[0082] In order to measure the influence of P2 on the structural stability when thermal runaway occurs in the battery cell 10, the following test was carried out.

[0083] Measurement conditions: A plurality of battery cells 10 equipped with a pressure reducing mechanism 12 having a pressure P1 of 1.1 MPa were prepared, and the burst pressure values ​​P2 of the outer cases 11 of the plurality of battery cells 10 were taken in equal increments from 1.1 to 2.3, and the results are shown in the table below.

[0084] [Table 1]

[0085] As can be seen from the above test results, when the burst pressure value P2 of the outer case 11 of the battery cell 10 is 1.7 MPa or higher, the outer case 11 remains in a relatively stable state even if the pressure reduction mechanism 12 of the battery cell 10 ruptures. However, when the burst pressure value P2 of the outer case 11 of the battery cell 10 is less than 1.7 MPa, the outer case 11 of the battery cell 10 is likely to rupture immediately after the pressure reduction mechanism 12 ruptures, and the structural stability and directional pressure release stability of the battery cell 10 are inferior.

[0086] In the present application, the burst pressure P2 of the outer case 11 is designed to be 1.7 MPa or more, which significantly improves the pressure resistance of the outer case 11. This design effectively improves the stability of the battery cell 10 in directional pressure release from the pressure reduction mechanism 12, while reducing the risk of the outer case 11 bursting due to pressure release from the pressure reduction mechanism 12, effectively improving the structural stability and safety of the battery cell 10.

[0087] According to some embodiments of the present application, P2 / P1≧1.35.

[0088] Specifically, the ratio of P2 to P1 may be any number equal to or greater than 1.35, such as 1.35, 1.36, 1.38, 1.4, 1.5, 1.8, 2, and the like.

[0089] In some embodiments, the ratio of P2 to P1 may be greater than 1.4. Illustratively, the ratio of P2 to P1 may be equal to 1.5.

[0090] If the ratio of P2 to P1 is too small (i.e., P1 approaches P2), the battery cell 10 will experience thermal runaway, and after the pressure reduction mechanism 12 is activated, the outer case 11 will likely burst shortly after the pressure reduction mechanism 12 bursts, causing the battery to fail. If the ratio of P2 to P1 is designed to be 1.35 or greater, a certain safety margin will exist between the pressure of the pressure reduction mechanism 12 and the withstand pressure value of the outer case 11, thereby improving the likelihood that the pressure reduction mechanism 12 will burst before the outer case 11 and further reducing the risk that the outer case 11 will burst and fail along with the pressure reduction mechanism 12, effectively improving the structural stability and safety of the battery cell 10.

[0091] According to some embodiments of the present application, P2-P1≧0.4 MPa.

[0092] Specifically, the difference between P2 and P1 may be any value equal to or greater than 0.4 MPa, such as 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.8 MPa, 1 MPa, 2 MPa, etc. Illustratively, the difference between P2 and P1 may be equal to 1.2 MPa.

[0093] If the difference between P2 and P1 is too small (i.e., P1 approaches P2), the battery cell 10 will experience thermal runaway, and after the pressure reduction mechanism 12 is activated, the outer case 11 will likely burst shortly after the pressure reduction mechanism 12 bursts, causing the battery to fail. If the difference between P2 and P1 is designed to be 0.4 MPa or greater, a safety margin can be further ensured between the pressure of the pressure reduction mechanism 12 and the withstand pressure value of the outer case 11, improving the likelihood that the pressure reduction mechanism 12 will burst before the outer case 11 and further reducing the risk that the outer case 11 will burst and fail along with the pressure reduction mechanism 12, effectively improving the structural stability and safety of the battery cell 10.

[0094] In some embodiments, 0.5 MPa≦P1≦1.3 MPa.

[0095] Specifically, P1 may be any value between 0.5 MPa and 1.3 MPa, and for example, P1 may be 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, or the like.

[0096] In some embodiments, P1 may be any value between 0.7 MPa and 1.1 MPa, for example, P1 may be 0.72 MPa, 0.75 MPa, 0.85 MPa, 0.92 MPa, 1.08 MPa, etc. Illustratively, P1 is 1.1 MPa.

[0097] If P1 is set too small, the pressure reduction mechanism 12 of the battery cell 10 is likely to operate prematurely, affecting the service life of the battery cell 10. If P1 is set too large, the requirements for the pressure resistance strength of the outer case 11 are too high and the pressure release needs of the battery cell 10 cannot be met. By designing P1 to be between 0.5 MPa and 1.3 MPa, the pressure release needs of the battery cell 10 can be effectively met.

[0098] According to some embodiments of the present application, still referring to FIG. 3, the outer case 11 includes a housing 111 and an end cover 112, and the housing 111 has an opening.

[0099] The housing 111 may be a hollow structure with an opening at one end, or may be a hollow structure with openings at opposite ends. The housing 111 may be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. The end cover 112 is a member that seals the opening of the housing 111 to isolate the internal environment of the battery cell 10 from the external environment. The end cover 112 and the housing 111 collectively define a sealed space for accommodating the electrode assembly, electrolyte, and other components. The end cover 112 may be connected to the housing 111 by welding or seaming, thereby sealing the opening of the housing 111. The shape of the end cover 112 may be adapted to the shape of the outer case 11. For example, if the housing 111 has a rectangular parallelepiped structure, the end cover 112 may be a rectangular plate-like structure that fits the outer case 11; or if the housing 111 is a cylinder, the end cover 112 may be a circular plate-like structure that fits the housing 111. The end cover 112 may be made of several materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0100] The battery cell 10 may have one or two end covers 112. In an embodiment in which the housing 111 is a hollow structure with openings at both ends, two end covers 112 may be provided correspondingly, with the two end covers 112 sealing the two openings of the housing 111, respectively, and the two end covers 112 and the housing 111 jointly defining a sealed space. In an embodiment in which the housing 111 is a hollow structure with an open end, one end cover 112 may be provided correspondingly, with the end cover 112 sealing the opening at one end of the housing 111, and the one end cover 112 and the housing 111 jointly defining a sealed space.

[0101] In some embodiments, the first wall is an end cover 112 and the pressure reducing mechanism 12 is installed in the end cover 112, as shown in FIG.

[0102] In another embodiment, the first wall is any wall portion of the housing 111. As shown in FIG. 4 , which is an exploded perspective view of a battery cell according to another embodiment of the present application, the pressure reducing mechanism 12 may be installed at the bottom of the housing 111, and the first wall is the bottom wall of the housing 111, and the first wall is installed opposite the end cover 112.

[0103] In the above technical solution, the pressure reducing mechanism is installed on the bottom wall of the housing 111. When the battery cell experiences thermal runaway, it can prevent the waste generated by the thermal runaway from being directly sprayed into the passenger space, thereby improving the safety of the user.

[0104] 3 , the battery cell 10 further includes a terminal 14, one end of which is electrically connected to the electrode assembly 13 housed in the outer case 11, and which is used to extract electrical energy from the battery cell 10. Generally, two terminals 14 are provided, one being a positive terminal and the other a negative terminal, and the positive terminal and the negative terminal may be located on the same side of the battery cell 10 or on opposite sides of the battery cell 10.

[0105] In some embodiments, the pole terminal 14 may be attached to the end cover 112 , and of course, the pole terminal 14 may be attached to the housing 111 .

[0106] The end cover 112 can be connected to the housing 111 by welding, seaming, or the like.

[0107] In addition, when the outer case 11 includes a housing 111 and an end cover 112 connected to the housing 111, P2 refers to the burst pressure value of the end cover 112 itself, the housing 111 itself, and the connection between the end cover 112 and the housing 111.

[0108] The burst pressure value of the area of ​​the outer case 11 other than the pressure reducing mechanism is designed to be 1.7 MPa or more, which effectively ensures the connection stability of the connection between the housing 111 and the end cover 112 and the pressure resistance stability of the entire outer case 11 when thermal runaway occurs in the battery cell 10.

[0109] According to some embodiments of the present application, continue to refer to Figure 3 and further refer to Figures 5 and 6. Figure 5 is a structural schematic diagram of an end cover according to some embodiments of the present application, and Figure 6 is a structural schematic diagram of a housing according to some embodiments of the present application. The end cover 112 is a rectangular plate, and the width of the end cover 112 is W, and W≦40 mm. Specifically, the width W of the end cover 112 is 40 mm or less and may be any number greater than 0, for example, W may be 40 mm, 38 mm, 30 mm, 25 mm, 10 mm, 5 mm, etc.

[0110] In some embodiments, the width W of the end cover 112 is greater than or equal to 5 mm and less than or equal to 40 mm.

[0111] In some embodiments, as shown in FIGS. 5 and 6 , the thickness H3 of the battery cell 10 (the thickness direction of the battery cell 10 extends along the first direction X) may be any value less than or equal to 40 mm and greater than 0, for example, H3 may be 40 mm, 38 mm, 30 mm, 25 mm, 10 mm, 5 mm, etc.

[0112] In order to measure the effect of the width W of the end cover 112 on P2, the following test was carried out.

[0113] Measurement conditions: A plurality of battery cells 10 were prepared, each equipped with a pressure reducing mechanism 12 with a pressure P1 of 1.1 MPa, and the thicknesses of the housing 111 and end cover 112 of the outer case 11 of the plurality of battery cells 10 were all constant. The results are shown in the table below.

[0114] [Table 2]

[0115] As can be seen from the above measurement results, P2 decreases as the width W of the end cover 112 increases; when the width W of the end cover 112 is greater than 40 mm, the structural stability of the outer case 11 does not meet the requirements. The wider the end cover 112, the less deformation resistance the end cover 112 has, and the more susceptible the end cover 112 is to deformation when thermal runaway occurs in the battery cells 10 and the end cover 112 is subjected to force. The deformation of the end cover 112 directly affects the connection stability between the end cover 112 and the housing 111, thereby reducing the pressure resistance of the connection between the end cover 112 and the housing 111. Designing the width of the end cover 112 to be 40 mm or less effectively ensures the deformation resistance of the end cover 112, thereby effectively improving the pressure resistance of the connection between the housing 111 and the end cover 112.

[0116] At the same time, to ensure the energy density and manufacturing feasibility of the battery cell 10, the width W of the end cover 112 can be 5 mm or more.

[0117] In some embodiments, the end cover 112 is a rectangular plate, and the length of the end cover 112 is L, where L≦1200 mm.

[0118] Specifically, the length L of the end cover 112 may be any value that is equal to or less than 1200 mm and greater than W, for example, L may be 1200 mm, 1000 mm, 800 mm, 300 mm, 80 mm, 50 mm, etc.

[0119] In some embodiments, the length L of the end cover 112 may be greater than or equal to 100 mm and less than or equal to 1200 mm.

[0120] The longer the end cover 112, the less deformation resistance the end cover 112 has and the more susceptible it is to deformation when thermal runaway occurs in the battery cell 10 and the end cover 112 is subjected to force. The deformation of the end cover 112 directly affects the stability of the connection between the end cover 112 and the housing 111, thereby reducing the pressure resistance of the connection between the end cover 112 and the housing 111. Designing the length of the end cover 112 to be 1200 mm or less effectively ensures the deformation resistance of the end cover 112 and thereby effectively improves the pressure resistance of the connection between the housing 111 and the end cover 112. At the same time, to ensure the energy density of the battery cell 10 and feasibility in manufacturing, the length L of the end cover 112 can be 100 mm or more.

[0121] According to some embodiments of the present application, the thickness of the end cover 112 is H1, which satisfies 1 mm≦H1≦5 mm.

[0122] Specifically, the thickness H1 of the end cover 112 may be any value between 1 mm and 5 mm, for example, H1 may be 1 mm, 2 mm, 3 mm, 4 mm, 4.5 mm, etc.

[0123] It should be noted that the end cover 112 may be of either a constant thickness design or a unequal thickness design, and when the end cover 112 has a constant thickness structure, H1 refers to the wall thickness of the end cover 112, i.e., the wall thickness of the end cover 112 may be any value between 1 mm and 5 mm, for example, the wall thickness of the end cover 112 may be 1 mm, 2 mm, 3 mm, 4 mm, 4.5 mm, etc. The unequal thickness structure of the end cover 112 means that the minimum thickness of the end cover 112 may be 1 mm or more, and the maximum thickness of the end cover 112 may be 5 mm or less.

[0124] In particular, the thickness of the end cover 112 here does not include the thickness of each functional area (e.g., the liquid injection port installation area, the electrode terminal installation area, the installation area for the pressure reducing mechanism 12, etc.) that may be installed on the end cover 112; in other words, H1 refers to the thickness of the end cover 112 excluding the functional areas.

[0125] To measure the effect of the thickness of the end cover 112 on P2, the following test was carried out.

[0126] Measurement conditions: A plurality of battery cells 10 were prepared, each equipped with a pressure reducing mechanism 12 with a pressure P1 of 1.1 MPa, and the thickness of the housing 111 and the width of the end cover 112 of the outer case 11 of the plurality of battery cells 10 were all constant values. The results are shown in the table below.

[0127] [Table 3]

[0128] As can be seen from the above test results, if the thickness of the end cover 112 is less than 1 mm, the structural stability of the outer case does not meet the requirements. If the thickness of the end cover 112 is more than 5 mm, the energy density of the battery cell 10 decreases. The minimum thickness of the end cover 112 is 1 mm or more, which can effectively improve the deformation resistance of the end cover 112 itself, thereby effectively improving the pressure resistance of the connection between the end cover 112 and the housing 111. The maximum thickness of the end cover 112 is 5 mm or less, which can ensure the deformation resistance of the end cover 112 itself while reducing the space occupied by the end cover 112, contributing to improving the energy density of the battery cell 10 and reducing the overall weight of the battery cell 10.

[0129] According to some embodiments of the present application, the end cover 112 is the wall of the outer case 11 that has the greatest thickness.

[0130] Specifically, the minimum thickness of the end cover 112 is greater than the thickness of each wall of the housing 111 .

[0131] In the process of modularizing the battery cell 10, the end cover 112 needs to be connected to the housing 111 by means such as welding. At the same time, assemblies such as pole terminals are often attached to the end cover 112, increasing the thickness of the end cover 112. The structural strength of the end cover 112 can be effectively guaranteed, thereby reducing the risk of the end cover 112 being deformed under force.

[0132] According to some embodiments of the present application, continue to refer to FIG. 6 and further refer to FIG. 7. FIG. 7 is a partial enlarged view of part A shown in FIG. 6 The wall thickness of the housing 111 is H2, satisfying 0.2 mm < H2 ≤ 3 mm.

[0133] Specifically, the thickness H2 of any wall of the housing 111 may be any value greater than 0.2 mm and less than or equal to 3 mm. For example, H2 may be 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 2 mm, 3 mm, etc.

[0134] It should be noted that each wall of the housing 111 may be designed with equal thickness or unequal thickness. When each wall of the housing 111 has an equal thickness structure, the thickness of the wall with the smallest thickness of the housing 111 is greater than 0.2 mm, and at the same time, the thickness of the wall with the largest thickness of the housing 111 should be less than or equal to 3 mm.

[0135] [[ID= sixteen]]When each wall of the housing 111 has an unequal thickness structure, the thickness of the part with the smallest thickness among all the walls of the housing 111 may be greater than 0.2 mm, and the thickness of the part with the largest thickness among all the walls of the housing 111 may be less than or equal to 3 mm.

[0136] In particular, here the thickness of each wall of the housing 111 does not include the thickness of each functional area (for example, the liquid injection hole installation part, the pole terminal attachment part, the attachment part of the pressure reduction mechanism 12, the step for accommodating the end cover of the housing opening, the corner of the housing, etc.) that may be installed in the housing 111. That is, H1 refers to the thickness outside the functional area of the housing 111.

[0137] At the same time, the thickness of each wall of the housing 111 may be the same or different.

[0138] To measure the effect of the thickness of the housing 111 on P2, the following test was performed.

[0139] Measurement conditions: A plurality of battery cells 10 were prepared, each equipped with a pressure reducing mechanism 12 with a pressure P1 of 1.1 MPa, and the thickness and width of the end covers 112 of the outer cases 11 of the plurality of battery cells 10 were all constant. The results are shown in the table below.

[0140] [Table 4]

[0141] As can be seen from the above test results, if the minimum thickness of the housing 111 is less than 0.2 mm, the structural stability of the outer case does not meet the requirements. If the thickness of the housing 111 is greater than 3 mm, the energy density of the battery cell 10 decreases. The minimum thickness of each wall of the housing 111 is greater than 0.2 mm, which effectively improves the deformation resistance of the housing 111, thereby effectively improving the pressure resistance of the connection between the end cover 112 and the housing 111 and the pressure resistance of the entire housing 111. A thickness of the housing 111 of 3 mm or less ensures the deformation resistance of the housing 111 while reducing the space occupied by the housing 111, contributing to improving the energy density of the battery cell 10 and reducing the overall weight of the battery cell 10.

[0142] According to some embodiments of the present application, the first wall is an end cover 112 .

[0143] The pressure reducing mechanism 12 may be installed in the end cover 112, which is useful for the production and assembly of the battery cell 10. When the battery cell 10 experiences thermal runaway, the gas inside the outer case 11 flows toward the pressure reducing mechanism 12, and the end cover 112 and the connection between the end cover 112 and the housing 111 are subjected to great pressure. However, by designing the burst pressure value of the entire outer case 11 to be 1.7 MPa or more, the pressure resistance of the connection between the end cover 112 and the housing 111 can be effectively guaranteed, thereby effectively improving the structural stability and safety of the outer case 11.

[0144] According to some embodiments of the present application, referring again to Figure 3 and further to Figure 8, Figure 8 is a partial cross-sectional view of an end cover and a housing welded together. End cover 112 is welded to housing 111, and the effective penetration depth of the weld between end cover 112 and housing 111 is D, which satisfies D≥200 μm.

[0145] The penetration depth is the distance between the deepest point of the base metal fusion zone and the base metal surface, and is the depth to which the base metal bead melts. In this embodiment, the effective penetration depth is the distance between the upper surface of the end cover 112 and the deepest point of the weld fusion zone between the end cover 112 and the housing 111.

[0146] D may be a value greater than 200 μm, such as 200 μm, 300 μm, 400 μm, or 500 μm.

[0147] By welding the end cover 112 to the housing 111, the connection stability between the end cover 112 and the housing 111 is effectively ensured, thereby effectively improving the pressure resistance of the connection between the end cover 112 and the housing 111. The effective penetration depth of the connection between the end cover 112 and the housing 111 is 200 μm or more, which further improves the pressure resistance of the connection between the end cover 112 and the housing 111.

[0148] According to some embodiments of the present application, D≦2000 μm is satisfied.

[0149] Specifically, D may be any value between 200 μm and 2000 μm, for example, D may be 200 μm, 500 μm, 800 μm, 1000 μm, 1500 μm, 2000 μm, or the like.

[0150] The effective penetration depth of the end cover 112 is designed to be 2000 μm or less, which avoids the problem of the thickness of the end cover 112 increasing due to excessive penetration depth requirements, and prevents the end cover 112 from being too thick and affecting the energy density of the battery cell 10.

[0151] According to some embodiments of the present application, the volumetric energy density of the battery cell 10 is T1, and T1≧600 Wh / L.

[0152] Volumetric energy density refers to the amount of energy stored in a given volume of material. T1 can be 600Wh / L, 610Wh / L, 620Wh / L, 630Wh / L, 640Wh / L, etc.

[0153] The burst pressure P2 of the outer case 11 is designed to be 1.7 MPa or more, and can be applied to high-energy density battery cells 10 with a volumetric energy density of 600 Wh / L or more. The burst pressure P2 of the outer case 11 is 1.7 MPa or more, which effectively reduces the risk of high-temperature, high-pressure gas generated by the large amount of energy released when the high-energy density battery cells 10 experience thermal runaway breaking through areas of the outer case 11 other than the pressure reduction mechanism 12.

[0154] According to some embodiments of the present application, T1≦1200 Wh / L is satisfied.

[0155] The outer case 11 having a burst pressure of 1.7 MPa or more is applied to the battery cell 10 having a volumetric energy density of 1200 Wh / L or less, and can further effectively improve the structural stability of the battery cell 10.

[0156] According to some embodiments of the present application, the weight energy density of the battery cell is T2, and T2≧220Wh / Kg.

[0157] Gravimetric energy density refers to the amount of energy stored in a given mass of material. T2 may be 220Wh / Kg, 230Wh / Kg, 240Wh / Kg, 250Wh / Kg, etc.

[0158] The burst pressure P2 of the outer case 11 is designed to be 1.7 MPa or more, and can be applied to high-energy density battery cells 10 with a weight energy density of 220 Wh / Kg or more. The burst pressure P2 of the outer case 11 is 1.7 MPa or more, which effectively reduces the risk of high-temperature, high-pressure gas generated by the large amount of energy released when the high-energy density battery cells 10 experience thermal runaway breaking through areas of the outer case 11 other than the pressure reduction mechanism 12.

[0159] According to some embodiments of the present application, T2≦500Wh / Kg is satisfied.

[0160] The outer case 11 having a burst pressure of 1.7 MPa or more is applied to the battery cell 10 having a volumetric energy density of 500 Wh / Kg or less, and can further effectively improve the structural stability of the battery cell 10.

[0161] According to some embodiments of the present application, the outer case 11 is a metal member.

[0162] As described above, the outer case 11 may be made of a metal material such as aluminum, aluminum alloy, or steel.

[0163] The outer case 11 is a metal component, and the metal outer case 11 has higher structural rigidity, outstanding deformation resistance, and excellent heat resistance compared to the outer case 11 made of plastic or other materials, which can further improve the structural stability of the battery cell 10.

[0164] Some embodiments of the present application provide a battery including a housing and a battery cell 10 according to any of the above-described solution means accommodated in the housing.

[0165] Some embodiments of the present application provide a power consumption device including the battery cell 10 of any of the above-described solution means for supplying electrical energy.

[0166] The power consumption device may be any of the above-described devices or systems that use a battery.

[0167] Referring to FIGS. 3 to 8, some embodiments of the present application provide a battery cell 10 including an outer case 11 and a pressure relief mechanism 12. The outer case 11 is a metal member. The outer case 11 includes a housing 111 and an end cover 112. The housing 111 has an opening, and the end cover 112 seals the opening. The housing 111 is welded to the end cover 112. The pressure relief mechanism 12 is installed on the end cover 112. The bursting pressure of the pressure relief mechanism 12 is P1, and the bursting pressure of the connection portion between the housing 111 and the end cover 112 is P2, where P2 > P1, P2 ≥ 1.7 MPa, P2 - P1 ≥ 0.4 MPa, 5 mm ≤ W ≤ 40 mm, 100 mm ≤ L ≤ 1200 mm, 1 mm ≤ H1 ≤ 5 mm, 0.2 mm < H2 ≤ 3 mm, 200 μm ≤ D ≤ 2000 μm, T1 ≥ 600 Wh / L, and T2 ≥ 220 Wh / Kg are satisfied.

[0168] where W is the width of the end cover 112, L is the length of the end cover 112, H1 is the thickness of the end cover 112, and H2 is the wall thickness of the housing 111. In this embodiment, the outer case 11 has a hexahedral structure, and the housing 111 includes two first side walls 1111 arranged opposite each other along a first direction X, two second side walls 1112 arranged opposite each other along a second direction Y, and a bottom wall 1113 arranged opposite the end cover in a third direction Z, where two of the first direction X, second direction Y, and third direction Z intersect at right angles, and the two first side walls 1111 are the walls with the largest area of ​​the outer case. The first side wall 1111, the second side wall 1112 and the bottom wall 1113 are all designed to be of equal thickness, but the first side wall 1111, the second side wall 1112 and the bottom wall 1113 have different thicknesses, D is the penetration depth of the weld between the end cover 112 and the housing 111, T1 is the volumetric energy density of the battery cell 10, and T2 is the gravimetric energy density of the battery cell 10.

[0169] [Table 5]

[0170] It should be noted that the features in the embodiments of the present application can be combined with each other unless they are inconsistent.

[0171] Although the present application has been described with reference to preferred embodiments, various modifications may be made and equivalents may be substituted for the elements thereof without departing from the scope of the present application. In particular, the technical features recited in each embodiment may be combined in any manner as long as there is no structural contradiction. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions encompassed by the claims. [Explanation of symbols]

[0172] 10 battery cells 11 Outer case 111 Housing 112 End cover 12 Pressure reducing mechanism 13 Electrode Assembly 14-pole terminal 20 Case 21 Part 1 22 Part 2 100 batteries 200 Controller 300 motor 1000 vehicles X 1st direction Y Second direction Z 3rd direction

Claims

1. an outer case including a first wall; a pressure reducing mechanism installed on the first wall, The pressure reducing mechanism has a burst pressure of P1, the outer case has a burst pressure of P2, and the battery cell satisfies P2≧1.7 MPa and P2>P1.

2. The battery cell of claim 1 , wherein P2 / P1≧1.

35.

3. The battery cell according to claim 1 or 2, wherein P2-P1≧0.4 MPa.

4. The battery cell according to any one of claims 1 to 3, wherein 0.5 MPa≦P1≦1.3 MPa.

5. 5. The battery cell according to claim 1, wherein the outer case includes a housing and an end cover, the housing having an opening, and the end cover sealing the opening.

6. The battery cell according to claim 5 , wherein the end cover is a rectangular plate, and the width of the end cover is W, and W≦40 mm.

7. The battery cell according to claim 5 or 6, wherein the end cover is a rectangular plate, and the length of the end cover is L, and L≦1200 mm is satisfied.

8. The battery cell according to any one of claims 5 to 7, wherein the end cover has a thickness H1 that satisfies 1 mm≦H1≦5 mm.

9. The battery cell according to any one of claims 5 to 8, wherein the end cover is a wall of the outer case having the greatest thickness.

10. The battery cell according to claim 9 , wherein the wall thickness of the housing is H2, and satisfies 0.2 mm<H2≦3 mm.

11. The battery cell according to any one of claims 5 to 10, wherein the first wall is the end cover.

12. The battery cell according to any one of claims 5 to 11, wherein the end cover is welded to the housing, and an effective penetration depth of the weld between the end cover and the housing is D, and D≧200 μm is satisfied.

13. The battery cell according to claim 12 , wherein D≦2000 μm.

14. The battery cell according to any one of claims 1 to 13, wherein the volumetric energy density of the battery cell is T1, and T1 ≥ 600 Wh / L is satisfied.

15. The battery cell according to claim 14 , wherein T1≦1200 Wh / L.

16. The battery cell according to any one of claims 1 to 15, wherein the weight energy density of the battery cell is T2, and T2 ≥ 220 Wh / Kg is satisfied.

17. The battery cell according to claim 16 , wherein T2≦500 Wh / Kg is satisfied.

18. The battery cell according to any one of claims 1 to 17, wherein the outer case is made of a metal material.

19. A battery comprising: a housing; and the battery cell according to any one of claims 1 to 18 housed in the housing.

20. A power consuming device comprising a battery cell according to any one of claims 1 to 18 for supplying electrical energy thereto.

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