Battery cell, battery, and electrical device

Abstract

The present application provides a battery cell (20), a battery (100), and an electrical device. The battery cell (20) comprises a casing (21), electrode assemblies (22), and a thermal insulation member (23); the casing (21) has an accommodating cavity (211); a plurality of electrode assemblies (22) are provided, and the plurality of electrode assemblies (22) are accommodated in the accommodating cavity (211); the thermal insulation member (23) is arranged between two adjacent electrode assemblies (22), wherein the thickness H of the thermal insulation member (23) and the energy E of each electrode assembly (22) satisfy the relationship: 25 Wh / mm≤E / H≤750 Wh / mm.

Description

Battery cells, batteries and electrical equipment

[0001] Cross-references

[0002] This application refers to Chinese patent application No. 202322372741.X, entitled “Battery Cell, Battery and Electrical Equipment”, filed on August 31, 2023, which is incorporated into this application in its entirety by reference. Technical Field

[0003] The present application belongs to the field of battery technology, and more specifically, relates to a battery cell, a battery, and an electrical device. Background Art

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important part of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0005] A battery includes a battery cell, which usually includes multiple electrode assemblies. During the charge and discharge process of the battery cell, once the battery experiences thermal runaway, a large amount of heat will be generated and the temperature will rise rapidly. In order to delay or block the spread of heat generated by the electrode assembly, a thermal insulation member is usually set between two adjacent electrode assemblies. However, since the thermal insulation member occupies more internal space of the battery cell, the volume energy density of the battery cell decreases, affecting the endurance performance of the electric vehicle.

[0006] Summary of the Invention

[0007] One of the purposes of the embodiments of the present application is to provide a battery cell, a battery, and an electrical device to solve the technical problem of reduced volume energy density of battery cells in the related art.

[0008] To achieve the above-mentioned purpose, the technical solution adopted in the embodiment of the present application is to provide a battery cell, comprising:

[0009] A housing having a cavity;

[0010] A plurality of electrode assemblies are accommodated in the cavity;

[0011] A heat insulating member is provided between two adjacent electrode assemblies;

[0012] The thickness H of the thermal insulation component and the energy E of the electrode assembly satisfy the following relationship: 25Wh / mm≤E / H≤750Wh / mm.

[0013] The battery cell provided in the embodiment of the present application has at least the following beneficial effects: the thermal insulation member of the battery cell provided in the embodiment of the present application is arranged between two adjacent electrode assemblies to slow down the heat propagation rate between the two adjacent electrode assemblies, and by limiting the thickness H of the thermal insulation member and the energy E of the electrode assembly to satisfy the relationship: 25Wh / mm≤E / H≤750Wh / mm, not only can the thermal insulation performance of the thermal insulation member meet the thermal insulation requirements between the two adjacent electrode assemblies, but it can also effectively improve the situation where the thickness H of the thermal insulation member is too large, effectively reduce the space occupied by the thermal insulation member, thereby effectively improving the space utilization rate of the battery cell, and effectively improving the volume energy density of the battery cell.

[0014] In some embodiments of the present application, the thickness H of the thermal insulation element is 1 mm-6 mm.

[0015] By adopting the above technical solution, on the premise that the thermal insulation performance of the thermal insulation member can meet the thermal insulation requirements between two adjacent electrode assemblies, the thickness H of the thermal insulation member is further limited, thereby further reducing the space occupied by the thermal insulation member, thereby further improving the volume energy density of the battery cell.

[0016] In some embodiments of the present application, the thermal insulation member is provided with thermal insulation pores.

[0017] By adopting the above technical solution, the thermal insulation performance of the thermal insulation component is effectively improved, thereby effectively delaying the heat propagation speed between two adjacent electrode assemblies and effectively improving the reliability of the battery cell.

[0018] In some embodiments of the present application, the pore diameter r of the thermal insulation pores is 10 nm-50 nm.

[0019] By adopting the above technical solution, the thermal insulation performance of the thermal insulation component is further improved, thereby further delaying the heat propagation speed between two adjacent electrode assemblies and further improving the reliability of the battery cell.

[0020] In some embodiments of the present application, the number of the thermal insulation pores is multiple, and the porosity N of the thermal insulation component is 95%-98%.

[0021] By adopting the above technical solution, the thermal insulation performance of the thermal insulation component is further improved, thereby further delaying the heat propagation speed between two adjacent electrode assemblies and further improving the reliability of the battery cell.

[0022] In some embodiments of the present application, one end of the thermal insulation pore passes through a side of the thermal insulation member facing one electrode assembly, and the other end of the thermal insulation pore passes through a side of the thermal insulation member facing another electrode assembly.

[0023] By adopting the above technical solution, the heat propagation speed between two adjacent electrode assemblies is further slowed down, thereby further improving the reliability of the battery cell.

[0024] In some embodiments of the present application, the battery cell further includes a liquid-repellent layer, which covers the surface of the thermal insulation member.

[0025] By adopting the above technical solution, the liquid-repellent layer can prevent the electrolyte in the battery cell from entering the insulation pores of the insulation component, thereby further slowing down the heat propagation speed between two adjacent electrode assemblies and further improving the reliability of the battery cell.

[0026] In some embodiments of the present application, the liquid-repellent layer includes at least one of a polytetrafluoroethylene member, a polyvinylidene fluoride member, and a polypropylene member.

[0027] By adopting the above technical solution, the lyophobic layer can effectively prevent the electrolyte in the battery cell from entering the thermal insulation pores of the thermal insulation component.

[0028] In some embodiments of the present application, the liquid-repellent layer is a liquid-repellent film, which is attached to the surface of the thermal insulation component; or, the liquid-repellent layer is a liquid-repellent coating, which is coated on the surface of the thermal insulation component.

[0029] By adopting the above technical solution, the lyophobic layer can effectively prevent the electrolyte in the battery cell from entering the thermal insulation pores of the thermal insulation component.

[0030] In some embodiments of the present application, the thermal insulation member is a liquid-phobic thermal insulation member.

[0031] By adopting the above technical solution, the risk of the electrolyte in the battery cell entering the insulating pores of the thermal insulation component is effectively reduced, thereby further slowing down the heat spread speed between two adjacent electrode assemblies and further improving the reliability of the battery cell.

[0032] In some embodiments of the present application, the thickness H of the thermal insulation member and the energy E of the electrode assembly satisfy the relationship: 150Wh / mm≤E / H≤550Wh / mm.

[0033] By adopting the above technical solution, the thermal insulation performance of the thermal insulation component can better meet the thermal insulation requirements between two adjacent electrode assemblies, while further reducing the space occupied by the thermal insulation component, thereby further improving the volume energy density of the battery cell.

[0034] In some embodiments of the present application, the thermal conductivity of the thermal insulation element is 0.01 W / mK-0.05 W / mK.

[0035] By adopting the above technical solution, the heat propagation speed between two adjacent electrode assemblies is further slowed down, thereby further improving the reliability of the battery cell.

[0036] In some embodiments of the present application, the electrode assembly includes a main body and a tab, and the thermal insulation member is disposed between the two main bodies and protrudes from the main body.

[0037] By adopting the above technical solution, the insulation area of ​​the insulation component is effectively increased, and the speed of heat conduction from the outer space of one electrode assembly to another electrode assembly is effectively slowed down, thereby further improving the reliability performance of the battery cell.

[0038] In some embodiments of the present application, the electrode assembly has a wound structure and includes a main body and a tab, the main body includes a straight area and a corner area arranged on the side of the straight area, and the thermal insulation member is arranged between the two straight areas and protrudes from the straight area.

[0039] By adopting the above technical solution, the insulation area of ​​the insulation component is effectively increased, and the speed of heat conduction from the outer space of one electrode assembly to another electrode assembly is effectively slowed down, thereby further improving the reliability performance of the battery cell.

[0040] In some embodiments of the present application, the thermal insulation member includes at least one of a porous silicon member, an aerogel member, a polystyrene member, a rock wool member, a glass wool member, and a polyurethane foam member.

[0041] By adopting the above technical solution, the heat propagation speed between two adjacent electrode assemblies is effectively slowed down, thereby further improving the reliability performance of the battery cell.

[0042] In some embodiments of the present application, the battery cell is a sodium ion battery cell, a sodium metal battery cell, a ternary lithium battery cell, or a lithium metal battery cell.

[0043] By adopting the above technical solution, the volume energy density of the above-mentioned various battery cells is effectively improved under the premise that the thermal insulation performance of the thermal insulation component can meet the thermal insulation requirements between two adjacent electrode assemblies.

[0044] An embodiment of the present application further provides a battery, comprising the battery cell described in any of the above embodiments.

[0045] The battery provided by the embodiments of the present application has at least the following beneficial effects: since the battery provided by the embodiments of the present application adopts the battery cell described in any of the above embodiments, the volume energy density of the battery is effectively improved.

[0046] An embodiment of the present application also provides an electrical device including the above-mentioned battery.

[0047] The electric device provided by the embodiment of the present application has at least the following beneficial effects: since the electric device provided by the embodiment of the present application adopts the battery described in any of the above embodiments, the battery life performance of the electric device is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0049] FIG1 is a schematic structural diagram of a vehicle provided in an embodiment of the present application;

[0050] FIG2 is a schematic diagram of an exploded structure of a battery in the vehicle shown in FIG1 ;

[0051] FIG3 is a schematic structural diagram of a battery cell in the battery shown in FIG2 ;

[0052] FIG4 is a schematic diagram of the front structure of the battery cell shown in FIG3 ;

[0053] FIG5 is a schematic cross-sectional view of the battery cell shown in FIG4 along line AA;

[0054] FIG6 is an enlarged structural diagram of the battery cell at position B shown in FIG5 ;

[0055] FIG7 is a schematic structural diagram of a thermal insulation member provided in an embodiment of the present application;

[0056] FIG8 is a schematic diagram of the assembly structure of the thermal insulation component and the electrode assembly provided in an embodiment of the present application.

[0057] Among them, the figure marks in the figure are: 1000, vehicle; 100, battery; 10, casing; 11, first part; 12, second part; 20, battery cell; 21, shell; 211, cavity; 22, electrode assembly; 221, main body; 2211, flat area; 2212, corner area; 222, tab; 23, thermal insulation; 231, thermal insulation pores; 232, thermal insulation body; 233, first protrusion; 234, second protrusion; 24, liquid-repellent layer; 25, cover; 200, controller; 300, motor. DETAILED DESCRIPTION

[0058] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0059] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0060] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0062] Currently, market developments indicate that batteries are increasingly being used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As battery applications continue to expand, market demand is also growing.

[0063] In related technologies, batteries include battery cells, which are the smallest storage units for storing electrical energy. Battery cells typically include multiple electrode assemblies. During the charge and discharge process of the battery cells, the electrode assemblies generate heat, especially when the electrode assemblies are about to experience thermal runaway. In order to slow the spread of heat generated by the electrode assemblies, thermal insulation is usually installed between two adjacent electrode assemblies. At the same time, to ensure that the thermal insulation can effectively isolate heat, the thermal insulation is usually thickened. However, this can easily result in the thermal insulation being too thick, causing the thermal insulation to occupy more internal space of the battery cell, thereby reducing the volume energy density of the battery cell and affecting the endurance performance of electric vehicles.

[0064] In order to improve the volume energy density of the battery cell, the thermal insulation member of the battery cell provided in the embodiment of the present application is arranged between two adjacent electrode assemblies to slow down the heat propagation rate between the two adjacent electrode assemblies. By limiting the thickness H of the thermal insulation member and the energy E of the electrode assembly to satisfy the relationship: 25Wh / mm≤E / H≤750Wh / mm, not only can the thermal insulation performance of the thermal insulation member meet the thermal insulation requirements between the two adjacent electrode assemblies, but it can also effectively improve the situation where the thickness H of the thermal insulation member is too large, effectively reduce the space occupied by the thermal insulation member, thereby effectively improving the space utilization rate of the battery cell and effectively improving the volume energy density of the battery cell.

[0065] The battery cells, batteries and electrical equipment using the batteries as power sources disclosed in the embodiments of the present application, wherein the electrical equipment may be, but is not limited to, vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys and electric tools, etc. The vehicle may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. Spacecraft include airplanes, rockets, space shuttles and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc. Electric 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.

[0066] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0067] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in an embodiment of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0068] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000 , but also as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .

[0069] Please refer to Figure 2, which is an exploded view of a battery 100 according to an embodiment of the present application. The battery 100 includes a housing 10 and a battery cell 20, which is housed within the housing 10. The housing 10 provides a storage space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which cover each other and together define a storage space for the battery cell 20. The second portion 12 can be a hollow structure with one end open. The first portion 11 can be a plate-like structure, with the first portion 11 covering the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. Alternatively, the first portion 11 and the second portion 12 can each be a hollow structure with one end open, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder or a rectangular parallelepiped.

[0070] In some embodiments, the box 10 may serve as part of the chassis structure of the vehicle 1000. For example, a portion of the box 10 may form at least a portion of the floor of the vehicle 1000, or a portion of the box 10 may form at least a portion of the cross member and longitudinal member of the vehicle 1000.

[0071] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Of course, the battery 100 may also be a battery module formed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection, and then the multiple battery modules are further connected in series, in parallel, or in a hybrid connection to form an entire battery cell, which is then housed within the housing 10. The battery 100 may also include other functional components, such as a busbar for electrically connecting the multiple battery cells 20.

[0072] Each battery cell 20 may be a secondary battery or a primary battery. A secondary battery refers to a battery cell 20 that can be recharged to activate the active material after the battery cell 20 is discharged and can continue to be used. A primary battery refers to a battery cell 20 that cannot be recharged to activate the active material after the battery cell 20 is exhausted and can continue to be used. The battery cell 20 may also be a lithium-ion battery, a ternary lithium battery cell, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., but is not limited thereto. The battery cell 20 may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell, or a battery cell 20 of another shape. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells, and polygonal prismatic batteries. Polygonal prismatic batteries, for example, hexagonal prismatic batteries, are not particularly limited in this application.

[0073] Of course, in some embodiments, the battery 100 may not include the box 10 , but rather a plurality of battery cells 20 may be electrically connected and formed into a whole through necessary fixing structures before being assembled into the vehicle 1000 .

[0074] In order to illustrate the technical solution provided by this application, a detailed description is given below with reference to specific drawings and embodiments.

[0075] First, please refer to Figures 3 to 6 together. An embodiment of the present application provides a battery cell 20, including a shell 21, an electrode assembly 22 and a thermal insulation member 23. The shell 21 has a cavity 211. There are multiple electrode assemblies 22, and the multiple electrode assemblies 22 are accommodated in the cavity 211. The thermal insulation member 23 is arranged between two adjacent electrode assemblies 22, wherein the thickness H of the thermal insulation member 23 and the energy E of the electrode assembly 22 satisfy the relationship: 25Wh / mm≤E / H≤750Wh / mm.

[0076] The shell 21 is a component for providing an internal environment of the battery cell 20 (i.e., the above-mentioned cavity 211), wherein the internal environment can be used to accommodate the electrode assembly 22 and other functional components. The shell 21 can be an independent component, and an opening can be set on the shell 21, and the electrode assembly 22 and other components can be placed in the internal environment through the opening. The shape of the shell 21 can be determined according to the specific shape of the electrode assembly 22. The shape of the shell 21 can be but not limited to a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Similarly, the size of the shell 21 can be determined according to the size of the electrode assembly 22. The material of the shell 21 can be but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0077] The battery cell 20 may also include a cover 25, which covers the opening of the housing 21 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the cover 25 can be adapted to match the shape of the housing 21 to fit the housing 21. In some embodiments, the cover 25 can be made of a material with a certain degree of hardness and strength. This prevents the cover 25 from deforming when subjected to compression or collision, thus providing the battery cell 20 with greater structural strength and improved reliability. The cover 25 can be made of, but not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In some embodiments, the cover 25 can also be provided with a pressure relief mechanism for relieving internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. In some embodiments, the cover 25 can also be provided with an insulating spacer to isolate the electrical connectors within the housing 21 from the cover 25 to reduce the risk of short circuits. The insulating spacer can be made of, but not limited to, plastic, rubber, etc.

[0078] The electrode assembly 22 is the component within the battery cell 20 where the electrochemical reaction occurs. The number of electrode assemblies 22 can be determined based on actual application needs. For example, the number of electrode assemblies 22 can be two, three, four, or five. The shape of the electrode assembly 22 can be, but is not limited to, cylindrical, flat, or polygonal. The electrode assembly 22 is primarily composed of a positive electrode sheet, a negative electrode sheet, and a separator, manufactured using a winding or lamination process. In some embodiments, multiple positive and negative electrode sheets can be provided, with the positive and negative electrode sheets alternately stacked. In other embodiments, multiple positive electrode sheets can be provided, with the negative electrode sheets folded to form multiple stacked folded sections, with a positive electrode sheet sandwiched between adjacent folded sections. In yet other embodiments, both the positive and negative electrode sheets are folded to form multiple stacked folded sections. In some embodiments, multiple separators can be provided, with multiple separators positioned between any adjacent positive or negative electrode sheets. In other embodiments, the separators can be provided continuously, folded or wound between any adjacent positive or negative electrode sheets. The positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector. For example, the positive electrode current collector has two opposing surfaces along its thickness, with the positive electrode active material disposed on either or both of the opposing surfaces. The negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector. For example, the negative electrode current collector has two opposing surfaces along its thickness, with the negative electrode active material disposed on either or both of the opposing surfaces. In some embodiments, the separator is a separator. This application does not specifically limit the type of separator; any known porous separator with good chemical and mechanical stability may be used. The battery cell 20 may also include an electrolyte, which acts as an ion conductor between the positive and negative electrode sheets. This application does not specifically limit the type of electrolyte; the electrolyte may be selected based on needs. During the charge and discharge process of the battery cell 20, active ions (e.g., lithium ions, sodium ions, etc.) are intercalated and released between the positive and negative electrode sheets through the electrolyte. The separator is set between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting while allowing active ions to pass through.

[0079] The thermal insulator 23 is a component used to block heat conduction between two adjacent electrode assemblies 22. In some embodiments, there are two electrode assemblies 22, and the thermal insulator 23 is disposed between the two electrode assemblies 22. In other embodiments, there are more than two electrode assemblies 22, and a thermal insulator 23 may be disposed between each two adjacent electrode assemblies 22. Alternatively, the multiple electrode assemblies 22 may be divided into multiple groups, with a thermal insulator 23 disposed between each two adjacent groups of electrode assemblies 22. The thermal insulator 23 may be, but is not limited to, a thermal insulation pad, a thermal insulation board, or a thermal insulation film. The materials of the thermal insulator 23 include, but are not limited to, porous silicon, aerogel, polystyrene, rock wool, glass wool, polyurethane foam, etc. In other words, the thermal insulator 23 includes at least one of porous silicon, aerogel, polystyrene, rock wool, glass wool, and polyurethane foam. In some embodiments, the thermal insulator 23 covers the entire surface of one electrode assembly 22 relative to the other electrode assembly 22. Of course, in other embodiments, the thermal insulator 23 may only cover a portion of the surface of one electrode assembly 22 relative to the other electrode assembly 22. The heat insulating member 23 may be attached between two adjacent electrode assemblies 22 , or the heat insulating member 23 may be spaced apart from the electrode assemblies 22 .

[0080] The energy E of the electrode assembly 22 refers to the maximum amount of electricity stored in the electrode assembly 22. The energy E of the electrode assembly 22 is measured as follows: at an ambient temperature of 25°C and constant current and voltage conditions, fully charge the battery cell 20, and fully release the electricity from the battery cell 20 under constant current conditions. The total amount of electricity released is Em. The total amount of electricity Em is divided by the number of electrode assemblies 22 in the battery cell 20 to obtain the energy E of each electrode assembly 22. The thickness H of the thermal insulation 23 refers to the dimension of the thermal insulation 23 along the direction from one electrode assembly 22 to the other electrode assembly 22. For example, the thickness H of the thermal insulation 23 is the dimension of the thermal insulation 23 along the Y-axis direction shown in Figures 3, 5, and 8. It should be noted that the thickness of the thermal insulation 23 refers to the thickness of the thermal insulation 23 measured after the thermal insulation 23 is removed from the cavity 211 and the thermal insulation 23 is restored to a state where the thickness no longer changes. The thickness H of the thermal insulation member 23 and the energy E of the electrode assembly 22 satisfy the relationship: 25Wh / mm≤E / H≤750Wh / mm, that is, the ratio of the energy E of the electrode assembly 22 to the thickness H of the thermal insulation member 23 is greater than or equal to 25Wh / mm (watt-hours / millimeter) and less than or equal to 750Wh / mm (watt-hours / millimeter). For example, the ratio of the energy E of the electrode assembly 22 to the thickness H of the thermal insulation member 23 may be 25Wh / mm, 100Wh / mm, 200Wh / mm, 300Wh / mm, 400Wh / mm, 500Wh / mm, 600Wh / mm, 700Wh / mm, 750Wh / mm, etc.

[0081] In order to facilitate understanding of the technical solution of the present application, the embodiments of the present application are further described below in conjunction with Table 1, Table 2 and Table 3.

[0082] Table 1:

[0083] Table 1 shows the thermal insulation effect of the thermal insulation member 23 between two adjacent electrode assemblies 22 when the ratio of the energy E of the electrode assembly 22 to the thickness H of the thermal insulation member 23 is less than 25Wh / mm.

[0084] Table 2:

[0085] Table 2 shows the thermal insulation effect of the thermal insulation member 23 between two adjacent electrode assemblies 22 when the ratio of the energy E of the electrode assembly 22 to the thickness H of the thermal insulation member 23 is greater than 750Wh / mm.

[0086] Table 3:

[0087] Table 3 shows the thermal insulation effect of the thermal insulation member 23 between two adjacent electrode assemblies 22 when the ratio of the energy E of the electrode assembly 22 to the thickness H of the thermal insulation member 23 is within the range of 25Wh / mm-750Wh / mm.

[0088] It should be noted that in Tables 1, 2 and 3, the above-mentioned heat transfer time t refers to the time required for heat to be transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22, and the temperature difference △T on the opposite sides of the thermal insulation member 23 refers to the temperature difference between the side of the thermal insulation member 23 facing one electrode assembly 22 and the side of the thermal insulation member 23 facing the other electrode assembly 22 after the heat is transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22. Temperature sensing devices can be set on the side of the thermal insulation 23 facing one electrode assembly 22 and the side of the thermal insulation 23 facing the other electrode assembly 22. The temperature sensing devices are electrically connected to an external control module (for example, a battery management module of the battery 100). In the event that thermal runaway occurs in one electrode assembly 22, the two temperature sensing devices respectively measure the peak temperature of the side of the thermal insulation 23 facing the electrode assembly 22 that has experienced thermal runaway and the peak temperature of the side of the thermal insulation 23 facing the electrode assembly 22 that has not experienced thermal runaway. The external control module can calculate the temperature difference △T on the opposite sides of the thermal insulation 23 based on the two peak temperature data, and can also calculate the time required for the side of the thermal insulation 23 facing the electrode assembly 22 that has not experienced thermal runaway to reach the peak temperature from the initial temperature, that is, obtain the heat transfer time t.

[0089] By comparing Table 1, Table 2, and Table 3, it can be found that when the ratio of the energy E of the electrode assembly 22 to the thickness H of the thermal insulation member 23 is less than 25Wh / mm, although the heat transfer time t and the temperature difference ΔT on the opposite sides of the thermal insulation member 23 are large, that is, the time required for heat to be transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22 is long, and the amount of heat transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22 is small, the thermal insulation member 23 is relatively stable. The thermal insulation effect between two adjacent electrode assemblies 22 is good, but the thickness H of the thermal insulation member 23 is large, so that the thermal insulation member 23 occupies too much space, which will cause the volume energy density of the battery cell 20 to decrease. When the ratio of the energy E of the electrode assembly 22 to the thickness H of the thermal insulation member 23 is greater than 750Wh / mm, the heat transfer time t and the temperature difference ΔT on the opposite sides of the thermal insulation member 23 are both small, that is, the time required for heat to be transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22 is short, and the heat transfer time t from the thermal insulation member 23 to the side of the thermal insulation member 23 facing the other electrode assembly 22 is short. The amount of heat transferred from the side facing one electrode assembly 22 to the side of the heat insulating member 23 facing the other electrode assembly 22 is relatively large, and the heat insulating member 23 has a poor heat insulating effect between two adjacent electrode assemblies 22. The heat insulating member 23 cannot meet the heat insulating requirements between two adjacent electrode assemblies 22, which will lead to a decrease in the reliability of the battery cell 20. When the ratio of the energy E of the electrode assembly 22 to the thickness H of the heat insulating member 23 is within the range of 25Wh / mm-750Wh / mm, the heat transfer time t and the temperature difference ΔT on the opposite sides of the heat insulating member 23 are both large, that is, the heat is transferred from the side facing one electrode assembly 22 to the side facing the other electrode assembly 22. It takes a long time for the heat insulation member 23 to be transferred from one side of the heat insulation member 23 facing one electrode assembly 22 to the side of the heat insulation member 23 facing the other electrode assembly 22, and the amount of heat transferred from the side of the heat insulation member 23 facing one electrode assembly 22 to the side of the heat insulation member 23 facing the other electrode assembly 22 is relatively small. The heat insulation member 23 has a good heat insulation effect between two adjacent electrode assemblies 22, so that the battery cell 20 has good reliability performance, and the thickness H of the heat insulation member 23 is also small, so that the space occupied by the heat insulation member 23 is also reduced, thereby effectively improving the volume energy density of the battery cell 20.

[0090] The thermal insulation member 23 of the battery cell 20 provided in the embodiment of the present application is arranged between two adjacent electrode assemblies 22 to slow down the heat propagation rate between the two adjacent electrode assemblies 22. By limiting the thickness H of the thermal insulation member 23 and the energy E of the electrode assembly 22 to satisfy the relationship: 25Wh / mm≤E / H≤750Wh / mm, not only can the thermal insulation performance of the thermal insulation member 23 meet the thermal insulation requirements between the two adjacent electrode assemblies 22, but it can also effectively improve the situation where the thickness H of the thermal insulation member 23 is too large, effectively reduce the space occupied by the thermal insulation member 23, thereby effectively improving the space utilization rate of the battery cell 20, and effectively improving the volume energy density of the battery cell 20.

[0091] In some embodiments of the present application, in order to enable the thermal insulation performance of the thermal insulation member 23 to better meet the thermal insulation requirements between two adjacent electrode assemblies 22, while further reducing the space occupied by the thermal insulation member 23, thereby further improving the volume energy density of the battery cell 20, the ratio of the thickness H of the thermal insulation member 23 to the energy E of the electrode assembly 22 is 150Wh / mm-550Wh / mm.

[0092] In some embodiments of the present application, referring to FIG. 6 , the thickness H of the thermal insulation member 23 is 1 mm (millimeter) to 6 mm (millimeter).

[0093] For example, the thickness H of the thermal insulation member 23 may be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, etc.

[0094] When the thickness H of the thermal insulation member 23 is 1 mm, the energy E of the electrode assembly 22 can be a maximum of 750Wh. When the thickness H of the thermal insulation member 23 is 6 mm, the energy E of the electrode assembly 22 can be a minimum of 150Wh. In other words, the energy E of the electrode assembly 22 is 150Wh-750Wh. For example, the energy E of the electrode assembly 22 can be 150Wh, 250Wh, 350Wh, 450Wh, 550Wh, 650Wh, 750Wh, etc.

[0095] By adopting the above technical solution, on the premise that the thermal insulation performance of the thermal insulation member 23 can meet the thermal insulation requirements between two adjacent electrode assemblies 22, the thickness H of the thermal insulation member 23 is further limited, thereby further reducing the space occupied by the thermal insulation member 23, thereby further improving the volume energy density of the battery cell 20.

[0096] In some embodiments of the present application, referring to FIG. 7 , the thermal insulation member 23 is provided with thermal insulation pores 231 .

[0097] The insulating pore 231 is a hollow portion of the insulating member 23. The insulating pore 231 can be a through-hole extending through any two surfaces of the insulating member 23. Alternatively, the insulating pore 231 can be a blind hole with one end extending through one surface of the insulating member 23 and the other end sealed. Alternatively, the insulating pore 231 can be a hollow structure with both ends sealed. The insulating pore 231 can be formed in the insulating member 23 by machining or by fabricating the insulating member 23 from a porous material.

[0098] In related technologies, the thermal conductivity of solids is generally greater than that of liquids, and the thermal conductivity of liquids is generally greater than that of gases. By opening thermal insulation pores 231 on the thermal insulation member 23, at least the solid thermal conduction path of the thermal insulation member 23 can be reduced, thereby effectively improving the thermal insulation performance of the thermal insulation member 23, thereby effectively slowing down the heat propagation speed between two adjacent electrode assemblies 22 and effectively improving the reliability performance of the battery cell 20.

[0099] In some embodiments of the present application, referring to FIG. 7 , the pore diameter r of the thermal insulation pore 231 is 10 nm (nanometer) to 50 nm (nanometer).

[0100] It should be noted that the pore size distribution of the insulating pores 231 can be set with reference to the national standard GB / T 21650.2-2008 and the WI-PCA-124 pore size distribution analysis work guide. For example, the pore size of the insulating pores 231 can be 10nm, 20nm, 30nm, 40nm, 50nm, etc.

[0101] In the related art, the mean free path of gas molecules is about 68 nm. By limiting the pore size r of the thermal insulation pores 231 to the range of 10 nm-50 nm, it is difficult for heat to be conducted from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22 through the thermal insulation pores 231 with the help of gas (such as air) as a heat conduction medium, thereby further improving the thermal insulation performance of the thermal insulation member 23, thereby further slowing down the heat propagation speed between the two adjacent electrode assemblies 22, and further improving the reliability performance of the battery cell 20.

[0102] In some embodiments of the present application, referring to FIG. 7 , there are multiple thermal insulation pores 231 , and the porosity N of the thermal insulation member 23 is 95%-98%.

[0103] The number of thermal insulation pores 231 can be determined according to actual application requirements. For example, the number of thermal insulation pores 231 can be 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, etc. The plurality of thermal insulation pores 231 can be evenly distributed on the thermal insulation member 23 or unevenly distributed on the thermal insulation member 23.

[0104] The porosity N of the thermal insulation member 23 refers to the ratio of the total volume of the plurality of thermal insulation pores 231 to the volume of the thermal insulation member 23. For example, the porosity N of the thermal insulation member 23 may be 95%, 96%, 97%, 98%, or the like.

[0105] It should be noted that the measurement method of the porosity N of the thermal insulation component 23 can be selected according to actual application needs. For example, the small molecular diameter inert gas (helium) replacement method can be used, combined with Archimedes' principle and Bohr's law, to measure the actual volume V1 of the thermal insulation component 23, and use a measuring tool to measure the apparent volume V2 of the thermal insulation component 23. According to the formula: Porosity N = (Apparent Volume V2-Actual Volume V1) / Apparent Volume V2×100%, the porosity N of the thermal insulation component 23 can be calculated.

[0106] By limiting the porosity N of the thermal insulation member 23 to the range of 95%-98%, at least the solid heat conduction path of the thermal insulation member 23 can be further reduced, further improving the thermal insulation performance of the thermal insulation member 23, thereby further slowing down the heat propagation speed between two adjacent electrode assemblies 22, and further improving the reliability performance of the battery cell 20.

[0107] In some embodiments of the present application, the porosity N of the thermal insulation member 23 is 95%-98%, and the pore size r of the thermal insulation pore 231 is 10nm-50nm, that is, the porosity N of the thermal insulation member 23 and the pore size r of the thermal insulation pore 231 satisfy the relationship: 9.5≤N×r≤49.

[0108] To facilitate understanding of the technical solution of the present application, the embodiments of the present application are further described below in conjunction with Tables 4 and 5.

[0109] Table 4:

[0110] Table 4 shows the thermal insulation effect of the thermal insulation member 23 between two adjacent electrode assemblies 22 when the product of the porosity N of the thermal insulation member 23 and the pore size r of the thermal insulation pore 231 is less than 9.5 and when the product of the porosity N of the thermal insulation member 23 and the pore size r of the thermal insulation pore 231 is greater than 49.

[0111] Table 5:

[0112] Table 5 shows the thermal insulation effect of the thermal insulation member 23 between two adjacent electrode assemblies 22 when the product of the porosity N of the thermal insulation member 23 and the pore diameter r of the thermal insulation pores 231 is within the range of 9.5-49.

[0113] It should be noted that in Tables 4 and 5, the above-mentioned heat transfer time t refers to the time required for heat to be transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22, and the temperature difference △T on the opposite sides of the thermal insulation member 23 refers to the temperature difference between the side of the thermal insulation member 23 facing one electrode assembly 22 and the side of the thermal insulation member 23 facing the other electrode assembly 22 after heat is transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22.

[0114] By comparing Table 4 and Table 5, it can be found that when the product of the porosity N of the thermal insulation member 23 and the pore diameter r of the thermal insulation pore 231 is less than 9.5 and when the product of the porosity N of the thermal insulation member 23 and the pore diameter r of the thermal insulation pore 231 is greater than 49, the heat transfer time t and the temperature difference ΔT on the opposite sides of the thermal insulation member 23 are both small, that is, the time required for heat to be transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22 is short, and the amount of heat transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22 is large, and the thermal insulation effect of the thermal insulation member 23 between the two adjacent electrode assemblies 22 is poor, which will lead to the battery cell. The reliability performance of the body 20 is reduced; when the product of the porosity N of the thermal insulation member 23 and the pore size r of the thermal insulation pores 231 is within the range of 9.5-49, the heat transfer time t and the temperature difference △T on the opposite sides of the thermal insulation member 23 are both large, that is, the time required for heat to be transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22 is longer, and the amount of heat transferred from the side of the thermal insulation member 23 facing one electrode assembly 22 to the side of the thermal insulation member 23 facing the other electrode assembly 22 is less, and the thermal insulation effect of the thermal insulation member 23 between the two adjacent electrode assemblies 22 is better, thereby effectively delaying the heat propagation speed between the two adjacent electrode assemblies 22, and effectively improving the reliability performance of the battery cell 20.

[0115] In some embodiments of the present application, referring to FIG. 7 , one end of the thermal insulation pore 231 passes through a side of the thermal insulation member 23 facing one electrode assembly 22 , and the other end of the thermal insulation pore 231 passes through a side of the thermal insulation member 23 facing another electrode assembly 22 .

[0116] In other words, the thermal insulation pores 231 are through-hole structures, and the direction of extension of the thermal insulation pores 231 is generally from one electrode assembly 22 to the other electrode assembly 22. Thus, in the event of thermal runaway of an electrode assembly 22, heat enters the thermal insulation pores 231 through one end of the thermal insulation pores 231, leaves the thermal insulation pores 231 through the other end of the thermal insulation pores 231, and is finally conducted to the other electrode assembly 22. During this process, heat must pass through the entire thermal insulation pores 231 along the length of the thermal insulation pores 231 from one electrode assembly 22 before being conducted to the other electrode assembly 22. This further slows the heat spread between two adjacent electrode assemblies 22, thereby further improving the reliability of the battery cell 20.

[0117] In some embodiments of the present application, referring to FIG. 6 , the battery cell 20 further includes a lyophobic layer 24 , which covers the surface of the thermal insulation member 23 .

[0118] The lyophobic layer 24 is a component used to separate the thermal insulation member 23 from the electrolyte of the battery cell 20. In some embodiments, the lyophobic layer 24 covers the entire surface of the thermal insulation member 23. Of course, in other embodiments, the lyophobic layer 24 may only cover the portion of the surface of the thermal insulation member 23 that is immersed in the electrolyte. In some embodiments, the lyophobic layer 24 is a lyophobic film, which is attached to the surface of the thermal insulation member 23. In other implementations, the lyophobic layer 24 is a lyophobic coating, which is applied to the surface of the thermal insulation member 23. The material of the lyophobic layer 24 can be, but is not limited to, polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, etc.

[0119] By adopting the above technical solution, the liquid-repellent layer 24 can prevent the electrolyte in the battery cell 20 from entering the insulation pores 231 of the insulation component 23, thereby further slowing down the heat propagation speed between two adjacent electrode assemblies 22 and further improving the reliability performance of the battery cell 20.

[0120] In other embodiments of the present application, the thermal insulation member 23 is a liquid-repellent thermal insulation member.

[0121] In other words, in this embodiment, the thermal insulation member 23 is made of a material having both thermal insulation and liquid-repellent properties, such as a surface-branched fluorinated modified material of polyacrylonitrile, a surface-branched fluorinated modified material of polycaprolactone, or a surface-branched fluorinated modified material of polysulfone.

[0122] By adopting the above-mentioned technical solution, the risk of the electrolyte in the battery cell 20 entering the insulating pores 231 of the thermal insulation component 23 is effectively reduced, thereby further delaying the heat propagation speed between the two adjacent electrode assemblies 22, further improving the reliability performance of the battery cell 20, and there is no need to additionally set up liquid-repellent components on the surface of the thermal insulation component 23, which effectively simplifies the internal structure of the battery cell 20, thereby further improving the internal space utilization of the battery cell 20 and further improving the volume energy density of the battery cell 20.

[0123] In some embodiments of the present application, the thermal conductivity of the thermal insulation member 23 is 0.01 W / m·K (Watt / meter·degree)-0.05 W / m·K (Watt / meter·degree).

[0124] The thermal conductivity of the thermal insulation member 23 may be determined according to actual application requirements. For example, the thermal conductivity of the thermal insulation member 23 may be 0.01 W / m·K, 0.02 W / m·K, 0.03 W / m·K, 0.04 W / m·K, 0.05 W / m·K, etc.

[0125] By limiting the thermal conductivity of the heat insulating member 23 to the above range, the heat propagation speed between two adjacent electrode assemblies 22 is further slowed down, thereby further improving the reliability of the battery cell 20 .

[0126] In some embodiments of the present application, referring to FIG. 8 , the electrode assembly 22 includes a main body 221 and an electrode tab 222 , and the thermal insulation member 23 is disposed between the two main bodies 221 and protrudes from the main body 221 .

[0127] The main body 221 is the main part of the electrode assembly 22. The main body 221 can be made of a positive electrode sheet, a negative electrode sheet, and a separator using a winding process or a stacking process. The tab 222 is electrically connected to the main body 221 and is used to input or output current to the main body 221.

[0128] The thermal insulation member 23 protrudes from the main body 221, which means that: taking any plane perpendicular to the thickness direction of the thermal insulation member 23 (for example, the Y-axis direction shown in Figure 8) as a reference plane, the projection of the thermal insulation member 23 along its thickness direction on the reference plane is a first projection, and the projection of the main body 221 along the thickness direction of the thermal insulation member 23 on the reference plane is a second projection, and at least part of the first projection protrudes from the edge of the second projection.

[0129] In some embodiments, referring to both FIG. 7 and FIG. 8 , the thermal insulation member 23 includes a thermal insulation body 232 and a first protrusion 233. The first protrusion 233 is disposed on at least one side of the thermal insulation body 232 along the width direction of the battery cell 20 (e.g., the X-axis direction shown in FIG. 8 ), and the first protrusion 233 protrudes from the main body 221. There may be two first protrusions 233, one on one side of the thermal insulation body 232 along the width direction of the battery cell 20, and the other on the other side of the thermal insulation body 232 along the width direction of the battery cell 20. The first protrusions 233 may abut against the inner wall of the housing 21 or be spaced apart from the inner wall of the housing 21.

[0130] In other embodiments, referring to both Figures 7 and 8 , the thermal insulation member 23 includes a thermal insulation body 232 and a second protrusion 234. The second protrusion 234 is disposed on the side of the thermal insulation body 232 facing the cover 25 and protrudes from the main body 221. The second protrusion 234 can abut against the cover 25 or be spaced apart from the cover 25.

[0131] In some other embodiments, please refer to Figures 7 and 8 together. The thermal insulation member 23 includes a thermal insulation body 232, a first protrusion 233 and a second protrusion 234. The number of the first protrusion 233 can be two. One first protrusion 233 is arranged on one side of the thermal insulation body 232 along the width direction of the battery cell 20 and protrudes from the main body 221. The other first protrusion 233 is arranged on the other side of the thermal insulation body 232 along the width direction of the battery cell 20 and protrudes from the main body 221. The second protrusion 234 is arranged on the side of the thermal insulation body 232 facing the cover body 25 and protrudes from the main body 221.

[0132] It is understood that when the thermal insulation member 23 is provided with the thermal insulation pores 231, the thermal insulation pores 231 may be provided in one or more of the thermal insulation body 232, the first protrusion 233, and the second protrusion 234. In some embodiments, the thermal insulation pores 231 are provided in the thermal insulation body 232. In other embodiments, the thermal insulation pores 231 are provided in the thermal insulation body 232, the first protrusion 233, and the second protrusion 234.

[0133] By adopting the above technical solution, the insulation area of ​​the insulation member 23 is effectively increased, and the speed of heat conduction from the outer space of one electrode assembly 22 to another electrode assembly 22 is effectively slowed down, thereby further improving the reliability performance of the battery cell 20.

[0134] In some embodiments of the present application, please refer to Figure 8, the electrode assembly 22 has a winding structure and includes a main body 221 and a pole ear 222, the main body 221 includes a straight area 2211 and a corner area 2212 arranged on the side of the straight area 2211, and the thermal insulation member 23 is arranged between the two straight areas 2211 and protrudes from the straight area 2211.

[0135] The electrode assembly 22 has a wound structure, that is, the main body 221 is made of positive electrode sheets, negative electrode sheets, and separators using a winding process. The straight area 2211 refers to a region with a parallel structure in the wound structure, that is, the negative electrode sheets, positive electrode sheets, and separators in the straight area 2211 are substantially parallel to each other, that is, the surface of each layer of negative electrode sheets, positive electrode sheets, and separators in the straight area 2211 of the electrode assembly 22 is a plane. The corner area 2212 refers to a region with a bent structure in the wound structure, that is, the negative electrode sheets, positive electrode sheets, and separators in the corner area 2212 are all bent, that is, the surface of each layer of negative electrode sheets, positive electrode sheets, and separators in the corner area 2212 of the electrode assembly 22 is a curved surface. There are two corner areas 2212, and the two corner areas 2212 are located on opposite sides of the straight area 2211 along the width direction of the battery cell 20.

[0136] In some embodiments, the thermal insulation member 23 includes a thermal insulation body 232 and a first protrusion 233. The number of the first protrusions 233 can be two, one first protrusion 233 is arranged on one side of the thermal insulation body 232 along the width direction of the battery cell 20, and the other first protrusion 233 is arranged on the other side of the thermal insulation body 232 along the width direction of the battery cell 20. The first protrusion 233 protrudes from the straight area 2211 but does not protrude from the corner area 2212.

[0137] In other embodiments, the thermal insulation member 23 includes a thermal insulation body 232 and a first protrusion 233. The number of the first protrusion 233 can be two, one first protrusion 233 is arranged on one side of the thermal insulation body 232 along the width direction of the battery cell 20, and the other first protrusion 233 is arranged on the other side of the thermal insulation body 232 along the width direction of the battery cell 20, and the first protrusion 233 protrudes from the corner area 2212.

[0138] By adopting the above technical solution, the insulation area of ​​the insulation member 23 is effectively increased, and the speed of heat conduction from the outer space of one electrode assembly 22 to another electrode assembly 22 is effectively slowed down, thereby further improving the reliability performance of the battery cell 20.

[0139] In some embodiments of the present application, please refer to Figures 3 to 8 , the battery cell 20 includes a shell 21, a cover 25, an electrode assembly 22, a thermal insulation member 23, and a liquid-repellent layer 24. The shell 21 has a cavity 211, and the cover 25 is provided at the opening of the shell 21 to isolate the cavity 211 from the external environment of the battery cell 20. There are multiple electrode assemblies 22, and multiple electrode assemblies 22 are accommodated in the cavity 211. The thermal insulation member 23 is provided between two adjacent electrode assemblies 22, wherein the thickness H of the thermal insulation member 23 and the energy E of the electrode assembly 22 satisfy the relationship: 25Wh / mm≤E / H≤750Wh / mm. The thermal insulation member 23 is provided with thermal insulation pores 231, the pore diameter r of the thermal insulation pores 231 is 10nm-50nm, the number of the thermal insulation pores 231 is multiple, and the porosity N of the thermal insulation member 23 is 95%-98%. At least a portion of the heat insulating member 23 protrudes from the outside of the gap between two adjacent electrode assemblies 22. The liquid-repellent layer 24 covers the surface of the heat insulating member 23.

[0140] In some embodiments of the present application, the battery cell 20 includes at least one of a sodium ion battery cell, a sodium metal battery cell, a ternary lithium battery cell, and a lithium metal battery cell.

[0141] In some implementations, the battery cell 20 is a sodium-ion battery cell, and the thermal insulation member 23 is disposed between two adjacent electrode assemblies 22 of the sodium-ion battery cell.

[0142] By adopting the above technical solution, the volume energy density of the above-mentioned various battery cells 20 is effectively improved, under the premise that the thermal insulation performance of the thermal insulation member 23 can meet the thermal insulation requirements between two adjacent electrode assemblies 22.

[0143] In the second aspect, referring to FIG. 2 , an embodiment of the present application further provides a battery 100 , comprising the battery cell 20 described in any of the above embodiments.

[0144] Since the battery 100 provided in the embodiment of the present application adopts the battery cell 20 described in any of the above embodiments, the volume energy density of the battery 100 is effectively improved.

[0145] In a third aspect, referring to FIG. 1 , an embodiment of the present application further provides an electrical device including the battery 100 described above.

[0146] Since the electric device provided in the embodiment of the present application adopts the battery 100 described in any of the above embodiments, the battery life performance of the electric device is effectively improved.

[0147] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: The battery cell comprises: A housing having a cavity; A plurality of electrode assemblies are accommodated in the cavity; A heat insulating member, disposed between two adjacent electrode assemblies; Wherein, the thickness H of the thermal insulation component and the energy E of the electrode assembly satisfy the relationship: 25Wh / mm≤E / H≤750Wh / mm.

2. The battery cell according to claim 1, characterized in that: The thickness H of the thermal insulation member is 1 mm-6 mm.

3. The battery cell according to claim 1 or 2, characterized in that: The heat insulating member is provided with heat insulating pores.

4. The battery cell according to claim 3, characterized in that: The pore diameter r of the thermal insulation pores is 10nm-50nm.

5. The battery cell according to claim 3 or 4, characterized in that: The number of the thermal insulation pores is multiple, and the porosity N of the thermal insulation component is 95%-98%.

6. The battery cell according to any one of claims 3 to 5, characterized in that: One end of the thermal insulation pore passes through a side of the thermal insulation member facing one of the electrode assemblies, and the other end of the thermal insulation pore passes through a side of the thermal insulation member facing another of the electrode assemblies.

7. The battery cell according to any one of claims 3 to 6, characterized in that: The battery cell further includes a liquid-repellent layer, and the liquid-repellent layer covers a surface of the thermal insulation member.

8. The battery cell according to claim 7, characterized in that: The liquid-repellent layer comprises at least one of a polytetrafluoroethylene member, a polyvinylidene fluoride member and a polypropylene member.

9. The battery cell according to claim 7 or 8, characterized in that: The liquid-repellent layer is a liquid-repellent film, and the liquid-repellent film is attached to the surface of the thermal insulation member; or The liquid-repellent layer is a liquid-repellent coating, and the liquid-repellent coating is coated on the surface of the thermal insulation component.

10. The battery cell according to any one of claims 3 to 6, characterized in that: The thermal insulation member is a liquid-repellent thermal insulation member.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The thickness H of the thermal insulation member and the energy E of the electrode assembly satisfy the relationship: 150Wh / mm≤E / H≤550Wh / mm.

12. The battery cell according to any one of claims 1 to 11, characterized in that: The thermal conductivity of the thermal insulation element is 0.01W / mK-0.05W / mK.

13. The battery cell according to any one of claims 1 to 12, characterized in that: The electrode assembly comprises a main body and an electrode tab, and the heat insulating member is arranged between the two main bodies and protrudes from the main bodies.

14. The battery cell according to any one of claims 1 to 12, characterized in that: The electrode assembly is in a winding structure and includes a main body and a pole ear. The main body includes a straight area and a corner area arranged on the side of the straight area. The heat insulation member is arranged between two straight areas and protrudes from the straight area.

15. The battery cell according to any one of claims 1 to 14, characterized in that: The heat insulating member comprises at least one of a porous silicon member, an aerogel member, a polyphenyl member, a rock wool member, a glass wool member and a polyurethane foam member.

16. The battery cell according to any one of claims 1 to 15, characterized in that: The battery cell is a sodium ion battery cell, a sodium metal battery cell, a ternary lithium battery cell or a lithium metal battery cell.

17. A battery, characterized in that: The battery comprises the battery cell according to any one of claims 1 to 16.

18. An electrical equipment, characterized in that: The electric device comprises the battery as claimed in claim 17.

Images