WO2024060093A1 - 电池单体、电池及用电装置 - Google Patents

电池单体、电池及用电装置 Download PDF

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Publication number
WO2024060093A1
WO2024060093A1 PCT/CN2022/120349 CN2022120349W WO2024060093A1 WO 2024060093 A1 WO2024060093 A1 WO 2024060093A1 CN 2022120349 W CN2022120349 W CN 2022120349W WO 2024060093 A1 WO2024060093 A1 WO 2024060093A1
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WIPO (PCT)
Prior art keywords
battery cell
battery
present application
thickness
minimum
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PCT/CN2022/120349
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English (en)
French (fr)
Inventor
蒲玉杰
李耀
陈小波
柯剑煌
杨飘飘
Original Assignee
宁德时代新能源科技股份有限公司
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Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2022/120349 priority Critical patent/WO2024060093A1/zh
Priority to CN202280089213.9A priority patent/CN118541851A/zh
Priority to CN202321977253.5U priority patent/CN220774539U/zh
Publication of WO2024060093A1 publication Critical patent/WO2024060093A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/103—Primary casings; Jackets or wrappings characterised by their shape or physical structure prismatic or rectangular
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/131—Primary casings; Jackets or wrappings characterised by physical properties, e.g. gas permeability, size or heat resistance
    • H01M50/133—Thickness
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M6/00—Primary cells; Manufacture thereof
    • H01M6/14—Cells with non-aqueous electrolyte
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • This application relates to the field of battery production technology, and in particular to battery cells, batteries and electrical devices.
  • Battery cells are widely used in electronic devices, such as mobile phones, laptops, battery cars, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes, electric tools and energy storage systems, etc.
  • the battery cells may include nickel-cadmium battery cells, nickel-hydrogen battery cells, lithium-ion battery cells, sodium-ion battery cells, secondary alkaline zinc-manganese battery cells, etc.
  • This application was made in view of the above-mentioned issues, and provides a battery cell, a battery and a power-consuming device, aiming to improve the safety of the battery cell to a certain extent.
  • the first aspect of this application provides a battery cell
  • the volume energy density of the battery cell is E
  • the minimum thickness of the battery cell is T
  • T and E satisfy: E ⁇ 600Wh/L, 6Wh /(L ⁇ mm) ⁇ E/T ⁇ 100Wh/(L ⁇ mm).
  • the volumetric energy density of the battery cell is E and the minimum thickness of the battery cell is T, satisfying: E ⁇ 600Wh/L, 6Wh/(L ⁇ mm) ⁇ E/T ⁇ 100Wh/(L ⁇ mm). Since a high-energy-density battery cell has a high gas production rate and heat release power when thermal runaway occurs, the minimum thickness of the battery cell is adjusted to adapt to the requirements of the high-energy battery cell to ensure that the battery Monolithic security. Moreover, the relationship between the volumetric energy density and the minimum thickness of the battery cell should be appropriately adjusted. When thermal runaway occurs inside the battery cell and gas is generated to form air pressure, the battery cell can function normally at the pressure relief mechanism of the battery cell.
  • Pressure relief thereby reducing the structural deformation of the battery cell, and reducing the risk of cracking of the battery cell in other areas other than the pressure relief mechanism (such as the connection between the casing and the end cover) due to the deformation of the battery cell, and further Reduce the risk of battery cell explosion.
  • appropriately adjusting the minimum thickness of the battery cell can improve the space utilization of the battery cell and help further improve the energy density.
  • the volumetric energy density E of the battery cell is 600Wh/L ⁇ E ⁇ 1000Wh/L.
  • the volumetric energy density of the battery cell is suitable such that the relationship between the volumetric energy density of the battery cell and the minimum thickness of the battery cell is within the safety design range of the battery cell, and more It is beneficial to improve the safety of the battery cells and reduce the overall structural deformation of the battery cells.
  • T and E satisfy: 8Wh/(L ⁇ mm) ⁇ E/T ⁇ 80Wh/(L ⁇ mm), optionally 20Wh/(L ⁇ mm) ⁇ E/T ⁇ 80Wh /(L ⁇ mm), more optionally 25Wh/(L ⁇ mm) ⁇ E/T ⁇ 40Wh/(L ⁇ mm).
  • the appropriate relationship between the volumetric energy density of the battery cell and the minimum thickness of the battery cell not only ensures that the pressure relief mechanism can normally relieve pressure after the battery cell undergoes thermal runaway, but also ensures that the battery cell can It not only ensures the safety of the battery, but also reduces the deformation of the battery cells after thermal runaway, basically ensuring the structural integrity of the battery cells.
  • the minimum thickness T of the battery cell is 10mm ⁇ T ⁇ 100mm, optionally 20mm ⁇ T ⁇ 60mm.
  • an appropriate thickness of the battery cell can ensure the overall strength and high volumetric energy density of the battery cell.
  • the battery cell includes a casing and an end cover.
  • the casing has an opening along its end, and the end cover is used to cover the opening.
  • connection strength and connection stability of the case and the end cover are improved, and the connection strength between the case and the end cover is reduced. Reduce the risk of cracking and ensure the safety of battery cells.
  • the housing is welded to the end cap.
  • the shell is welded to the end cover.
  • the welding method can fix the positions of the shell and the end cover, and can also increase the connection area between the shell and the end cover and increase the stability of the contact.
  • the connection strength is improved, and the welding process is convenient and controllable, which is conducive to large-scale preparation.
  • the melting point of the shell is c
  • the wall thickness of the shell is d
  • c and d satisfy: c/d ⁇ 400°C/mm, optionally 400°C/mm ⁇ c/d ⁇ 7500°C/mm.
  • the melting point c of the case and the wall thickness d of the case satisfy: c/d ⁇ 400°C/mm, adjust the relationship between the melting point c of the shell and the wall thickness d of the shell to ensure that the shell has a certain mechanical strength. It effectively reduces the deformation of the casing and reduces the risk of cracking of the battery cells in areas other than the pressure relief mechanism (such as the connection between the casing and the end cover) due to deformation of the battery cells.
  • the minimum wall thickness of the shell is d, and the ratio of T and d satisfies: 6T/d ⁇ 50, optionally 10 ⁇ T/d ⁇ 100.
  • the space and weight occupied by the case can be reduced while taking into account the safety design requirements of the thermal battery. , improve the volumetric energy density of the battery cell.
  • the minimum wall thickness d of the shell is 0.2 mm ⁇ d ⁇ 1.5 mm.
  • the minimum wall thickness d of the shell is reduced while meeting the safety design requirements, thereby improving the volume energy density of the battery cell.
  • the minimum thickness T of the battery cell is 10mm ⁇ T ⁇ 40mm, and the minimum wall thickness d of the case is 0.2mm ⁇ d ⁇ 0.6mm.
  • such an arrangement improves the volume energy density of the battery cell while satisfying the safety design of the battery cell, and is conducive to miniaturization of the battery cell.
  • the minimum thickness T of the battery cell is 40 mm ⁇ T ⁇ 60 mm
  • the minimum wall thickness d of the shell is 0.6 mm ⁇ d ⁇ 1 mm.
  • such an arrangement can improve the volumetric energy density of the battery cell and facilitate the miniaturization of the battery cell on the premise of satisfying the safety design of the battery cell.
  • the minimum thickness T of the battery cell is 60mm ⁇ T ⁇ 100mm, and the minimum wall thickness d of the case is 1mm ⁇ d ⁇ 1.5mm.
  • a suitable relationship between the minimum thickness T of the battery cell and the minimum wall thickness d of the case can improve the volumetric energy density of the battery cell, and the minimum wall thickness of the case is larger.
  • the minimum thickness D of the end cap is 1.5mm ⁇ D ⁇ 4.0mm.
  • such an arrangement can ensure the strength of the end cover, and can also increase the welding strength of the end cover and the shell, reducing the risk of cracking or breakage at the welding point.
  • the size of the battery cell along the first direction is W, and W and T satisfy: 1mm/mm ⁇ W/T ⁇ 60mm/mm, optionally 1.25mm/mm ⁇ W/T ⁇ 30mm/mm, more optionally 1.5mm/mm ⁇ W/T ⁇ 20mm/mm, the battery cell has the largest size in the first direction.
  • the size of the casing can be reasonably designed, and on the premise of meeting battery safety, the size in the first direction can be appropriately increased, so that the large surface of the casing has a larger area.
  • the heat transfer area can disperse the heat transferred to the shell and reduce the accumulation of heat when thermal runaway occurs, thus reducing the risk of the shell being penetrated.
  • the size W of the battery cell along the first direction is 100mm ⁇ W ⁇ 600mm.
  • appropriate dimensions of the battery cells along the first direction can improve space utilization within the battery cells to increase the volumetric energy density of the battery cells.
  • the size H of the battery cell along the second direction is H ⁇ 150mm, and the second direction is perpendicular to the first direction.
  • the size H of the battery cell along the second direction is H ⁇ 150 mm, so that the electrode assembly in the battery cell can be fully wetted by the electrolyte and reduce the defect that the middle part of the electrode assembly is not easily wetted.
  • the battery cells are square battery cells.
  • the safety effect of such prismatic battery cells is better.
  • a second aspect of the application also provides a battery, including the battery cell of the first aspect of the application.
  • the third aspect of the present application provides an electrical device, comprising the battery cell of the first aspect of the present application or the battery of the second aspect of the present application, wherein the battery cell or the battery is used to provide electrical energy.
  • Figure 1 is a schematic structural diagram of a vehicle according to some embodiments of the present application.
  • Figure 2 is a schematic diagram of the exploded structure of a battery according to some embodiments of the present application.
  • Figure 3 is a schematic diagram of the exploded structure of a battery cell according to some embodiments of the present application.
  • Figure 4 is a schematic structural diagram of a battery cell according to some embodiments of the present application.
  • Figure 5 is a schematic structural diagram of a battery cell casing according to some embodiments of the present application.
  • Figure 6 is a schematic structural diagram of an end cover of a battery cell according to some embodiments of the present application.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range “a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range “0-5" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the application.
  • the appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
  • connection should be understood in a broad sense.
  • connection can be a fixed connection, It can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components.
  • connection can be a fixed connection
  • connection can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components.
  • connection can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components.
  • “Plural” appearing in this application means two or more (including two).
  • battery cells may include lithium ion secondary battery cells, lithium ion primary battery cells, lithium sulfur battery cells, sodium lithium ion battery cells, sodium ion battery cells or magnesium ion battery cells, etc.
  • the embodiments of the present application are not limited to this.
  • the battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this.
  • Battery cells are generally divided into three types according to packaging methods: cylindrical battery cells, rectangular battery cells and soft-pack battery cells, and the embodiments of the present application are not limited to this.
  • the battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • the battery mentioned in the present application may include a battery module or a battery pack.
  • the battery generally includes a box for encapsulating one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells to a certain extent.
  • the battery cell includes an electrode assembly and an electrolyte.
  • the electrode assembly consists of a positive electrode sheet, a negative electrode sheet and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode active material layer is coated on the surface of the positive electrode current collector.
  • the current collector that is not coated with the positive electrode active material layer protrudes from the current collector that is coated with the positive electrode active material layer.
  • the current collector coated with the positive electrode active material layer is laminated to form a positive electrode tab.
  • the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, n-metal lithium compound (n ⁇ 3) or lithium manganate, etc.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer.
  • the negative electrode active material layer is coated on the surface of the negative electrode current collector.
  • the current collector that is not coated with the negative electrode active material layer protrudes from the current collector that is coated with the negative electrode active material layer.
  • the current collector coated with the negative electrode active material layer is laminated to serve as the negative electrode tab.
  • the material of the negative electrode current collector can be copper, and the negative electrode active material can be graphite, metallic lithium, silicon, silicon oxide, silicon-carbon alloy, germanium element, germanium oxide, carbon-germanium alloy, tin element, tin oxide or tin-carbon alloy of one or more.
  • the material of the isolation film can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc.
  • the electrode assembly may have a rolled structure or a laminated structure, and the embodiments of the present application are not limited thereto.
  • the positive electrode contains high-nickel ternary or lithium cobalt
  • the negative electrode contains high-capacity materials such as silicon or lithium metal. Electrode materials have emerged as the times require, and the battery cells of high specific energy systems designed with these materials, when thermal runaway occurs, both the gas production rate and heat release power are several times that of battery cells of low specific energy systems. Even hundreds of times. Therefore, the safety design of high specific energy battery cells faces some new challenges.
  • the minimum thickness of a battery cell is an important parameter in the design of the battery cell.
  • the thickness of the battery cell is too thin, it is not conducive to the improvement of the volumetric energy density; when the thickness of the battery cell is too thick.
  • the internal air pressure formed by thermal runaway gas production can easily cause excessive deformation of the casing along the thickness direction, causing the battery cells to crack, leading to the extreme event of battery thermal runaway explosion.
  • the volume energy density of the battery cell is E and the minimum thickness of the battery cell is T, satisfying: E ⁇ 600Wh/L, 6Wh/(L ⁇ mm ) ⁇ E/T ⁇ 100Wh/(L ⁇ mm).
  • Battery cells can be used in vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, power tools, energy storage systems, etc.
  • Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.
  • spacecraft include aircraft, rockets, space shuttles, spaceships, etc.
  • electric toys include fixed Type or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.
  • electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, for example, Electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, planers and more.
  • Electric drills Electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, planers and more.
  • an electric device 1000 according to an embodiment of the present application is used as an example.
  • FIG. 1 is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application.
  • the vehicle 1000 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.
  • the battery 100 is disposed inside the vehicle 1000 , and the battery 100 may be disposed at the bottom, head, or tail of the vehicle 1000 .
  • the battery 100 may be used to power the vehicle 1000 , for example, the battery 100 may 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 provide power to the motor 300 , for example, for starting, navigating and driving the vehicle 1000 .
  • the battery 100 can not only be used as an operating power source for the vehicle 1000 , but also can be used 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 .
  • FIG. 2 is an exploded view of the battery 100 provided by some embodiments of the present application.
  • the battery 100 includes a case and battery cells 10 .
  • the box may include an upper cover 20 and a lower cover 30 .
  • the upper cover 20 and the lower cover 30 cover each other.
  • the upper cover 20 and the lower cover 30 jointly define an accommodation space for accommodating the battery cells 10 .
  • the lower cover 30 can be a hollow structure with one end open, and the upper cover 20 can be a plate-like structure.
  • the upper cover 20 covers the open side of the lower cover 30 so that the upper cover 20 and the lower cover 30 jointly define a receiving space; the upper cover 20 can be a plate-shaped structure.
  • the box formed by the upper cover 20 and the lower cover 30 can be in various shapes, such as cylinder, rectangular parallelepiped, etc.
  • the battery 100 there may be a plurality of battery cells 10 , and the plurality of battery cells 10 may be connected in series, in parallel, or in mixed connection.
  • Mixed connection means that the plurality of battery cells 10 are connected in series and in parallel.
  • Multiple battery cells 10 can be directly connected in series, in parallel, or mixed together, and then the whole composed of multiple battery cells 10 can be accommodated in the box; of course, the battery 100 can also have multiple battery cells 10 connected in series first. They can be connected in parallel or mixed to form a battery module, and multiple battery modules can be connected in series, parallel or mixed to form a whole, and be accommodated in the box.
  • the battery 100 may also include other structures.
  • the battery 100 may further include a bus component for electrical connection between multiple battery cells 10 .
  • Each battery cell 10 may be a lithium-ion battery cell, a lithium-sulfur battery cell, a sodium-ion battery cell or a magnesium-ion battery cell, but is not limited thereto.
  • the battery cell 10 may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes.
  • FIG. 3 is a schematic diagram of the exploded structure of the battery cell 10 provided in some embodiments of the present application.
  • the battery cell 10 refers to the smallest unit that makes up the battery.
  • the battery cell 10 includes a case 101 , an end cap 102 , an electrode assembly 103 , an electrode terminal 104 and other functional components.
  • the end cap 102 refers to a component that covers the opening of the shell 101 to isolate the internal environment of the battery cell 10 from the external environment.
  • the shape of the end cap 102 can be adapted to the shape of the shell 101 to match the shell 101.
  • the end cap 102 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 102 is not easily deformed when squeezed and collided, so that the battery cell 10 can have a higher structural strength and the safety performance can also be improved.
  • Functional components such as electrode terminals 104 can be provided on the end cap 102. The electrode terminal 104 can be used to electrically connect to the electrode assembly 103 for outputting or inputting electrical energy of the battery cell 10.
  • the material of the end cap 102 can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this.
  • an insulating member may be provided inside the end cap 102 to isolate the electrical connection components in the housing 101 from the end cap 102 to reduce the risk of short circuit.
  • the insulating member may be plastic, rubber, or the like.
  • the case 101 is a component used to cooperate with the end cover 102 to form an internal environment of the battery cell 10 , wherein the formed internal environment can be used to accommodate the electrode assembly 103 , electrolyte, and other components.
  • the housing 101 and the end cover 102 may be independent components, and an opening may be provided on the housing 101.
  • the end cover 102 covers the opening at the opening to form the internal environment of the battery cell 10.
  • the end cap 102 and the shell 101 can also be integrated. Specifically, the end cap 102 and the shell 101 can form a common connection surface before other components are put into the shell. When it is necessary to encapsulate the inside of the shell 101 When the end cap 102 is closed, the housing 101 is closed.
  • the housing 101 can be of various shapes and sizes, such as rectangular parallelepiped, cylinder, hexagonal prism, etc. Specifically, the shape of the housing 101 can be determined according to the specific shape and size of the electrode assembly 103 .
  • the housing 101 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiment of the present application.
  • the housing 101 may also be provided with functional components such as electrode terminals and liquid injection holes.
  • the battery cell 10 further includes a pressure relief mechanism 105 .
  • the pressure relief mechanism 105 is used to relieve the internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold value.
  • the pressure relief mechanism 105 can be provided on the end cover 102 or the casing. 101 on.
  • the electrode assembly 103 is a component in the battery cell 10 where electrochemical reactions occur.
  • One or more electrode assemblies 103 may be contained within the housing 101 .
  • the electrode assembly 103 is mainly formed by winding a positive electrode piece and a negative electrode piece, and an isolation film is usually provided between the positive electrode piece and the negative electrode piece.
  • the portions of the positive electrode piece and the negative electrode piece that contain active material constitute the main body of the electrode assembly 103, and the portions of the positive electrode piece and the negative electrode piece that do not contain active material each constitute tabs.
  • the positive electrode tab and the negative electrode tab can be located together at one end of the main body or respectively located at both ends of the main body.
  • the positive active material and the negative active material react with the electrolyte, and the tabs are connected to the electrode terminals 104 to form a current loop.
  • FIG. 4 is a schematic diagram of the structure of a battery cell according to some embodiments of the present application.
  • the volume energy density of the battery cell 10 is E
  • the minimum thickness of the battery cell 10 is T
  • T and E satisfy: E ⁇ 600Wh/L , 6Wh/(L ⁇ mm) ⁇ E/T ⁇ 100Wh/(L ⁇ mm).
  • the battery cell 10 is the smallest unit that constitutes a battery, and can realize the functions of charging and discharging on its own.
  • the battery cell 10 may be a square case battery cell, a soft pack battery cell, or other battery cells.
  • the battery cell 10 may be in the shape of a flat body, a rectangular parallelepiped, or other shapes. In this application, the battery cell 10 is a rectangular parallelepiped as an example.
  • the battery cell 10 has three directions, which are the thickness direction x, the first direction y, and the second direction z.
  • the size of the battery cell 10 in the thickness direction x is smaller than the size in the second direction z.
  • the size of the battery cell 10 in the second direction z is The size is smaller than the size in the first direction y.
  • the size of the battery cell 10 in the second direction z refers to the size occupied by the case 101 and the end cover 102 of the battery cell 10 in the second direction z, excluding the size of the electrode terminals 104 protruding from the end cover 102 or the case 101 .
  • the thickness direction x, the first direction y and the second direction z are two perpendicular to each other.
  • the minimum thickness is the minimum thickness T of the battery cell 10 .
  • the calculation formula of the volumetric energy density of the battery cell 10 is as follows,
  • Volume energy density Capacity of the positive active material (A ⁇ h/kg) ⁇ Mass of the positive active material (kg) ⁇ Nominal voltage of 10 battery cells (V) / Volume of 10 battery cells (L)
  • increasing the volume energy density of the battery cell 10 mainly includes: starting from the battery chemical system, using high voltage or/and high capacity electrode materials such as high nickel ternary layered materials, high capacity lithium-rich manganese-based materials, silicon Based on negative electrode materials and lithium metal negative electrodes, etc.; without changing the battery chemical system, starting from the structural design, increasing the proportion of active materials in the battery cell by 10 units of mass or unit volume.
  • high voltage or/and high capacity electrode materials such as high nickel ternary layered materials, high capacity lithium-rich manganese-based materials, silicon Based on negative electrode materials and lithium metal negative electrodes, etc.
  • the structural design increasing the proportion of active materials in the battery cell by 10 units of mass or unit volume.
  • the volumetric energy density increases, higher requirements are placed on the safety design of the structure of the battery cell 10 .
  • the increase in the overall size of the battery cell 10 has the least impact on the manufacturing process of the battery cell 10 , and the battery cell 10 The increase in the size of 10 can increase the volumetric energy density.
  • the thickness of the battery cell 10 is a relatively sensitive parameter, especially for batteries with high specific energy chemical systems.
  • the minimum thickness of the battery cell 10 is too small, it is not conducive to improving the energy density of the battery cell 10; when the minimum thickness of the battery cell 10 is too large, the casing 101 and end cover 102 of the battery cell 10 are susceptible to damage. Force deformation, thereby reducing the strength of other areas of the battery cell 10 except the pressure relief mechanism 105 (such as the strength of the connection between the casing 101 and the end cover 102), so that other areas of the battery cell 10 except the pressure relief mechanism 105 The pressure relief mechanism 105 cracks earlier and cannot release the pressure normally, leading to an extreme event of thermal runaway explosion.
  • the volumetric energy density of the battery cell 10 is E and the minimum thickness of the battery cell 10 is T, satisfying: E ⁇ 600Wh/L, 6Wh/(L ⁇ mm) ⁇ E/T ⁇ 100Wh /(L ⁇ mm), can ensure the safety of the battery cell 10 and reduce the risk of explosion.
  • the volumetric energy density E of the battery cell 10 when the volumetric energy density E of the battery cell 10 is ⁇ 600Wh/L, the volumetric energy density of the battery cell 10 is required to be E and the minimum thickness of the battery cell 10 is T to satisfy: E ⁇ 600Wh/L, 6Wh/(L ⁇ mm) ⁇ E/T ⁇ 100Wh/(L ⁇ mm), thereby ensuring the safety of the battery cell 10 with high volumetric energy density.
  • the inventor found after in-depth research and a large number of experiments that the volumetric energy density of the battery cell 10 is E and the minimum thickness of the battery cell 10 is T, satisfying: E ⁇ 600Wh/L , 6Wh/(L ⁇ mm) ⁇ E/T ⁇ 100Wh/(L ⁇ mm). Since the high-energy-density battery cell 10 has a high gas production rate and heat release power when thermal runaway occurs, the minimum thickness of the battery cell 10 is adjusted to adapt to the requirements of the high-energy battery cell 10. This ensures the safety of the battery cells 10 . Moreover, the relationship between the volumetric energy density and the minimum thickness of the battery cell 10 is appropriately adjusted.
  • the battery cell 10 can release the pressure of the battery cell 10 .
  • the mechanism can release pressure normally, thereby reducing the structural deformation of the battery cell 10 and reducing the deformation of the battery cell 10 in other areas other than the pressure relief mechanism (such as the connection between the casing 101 and the end cover 102 ), further reducing the risk of battery explosion.
  • appropriately adjusting the minimum thickness of the battery cell 10 can improve the space utilization of the battery cell 10 and is conducive to further improvement of energy density.
  • the volumetric energy density of the battery cell 10 is E, where E is 600Wh/L, 650Wh/L, 700Wh/L, 750Wh/L, 800Wh/L, 850Wh/L, 900Wh/L , 950Wh/L, 1000Wh/L, 1050Wh/L, 1100Wh/L, 1150Wh/L, 1200Wh/L, 1250Wh/L, 1300Wh/L, 1350Wh/L, 1400Wh/L, 1450Wh/L, 1500Wh/L... etc., or within other ranges consisting of any two of the above endpoints.
  • the volumetric energy density of the battery cell 10 is E
  • the minimum thickness of the battery cell 10 is T
  • T and E satisfy that E/T is 6Wh/(L ⁇ mm), 10Wh/(L ⁇ mm), 15Wh/(L ⁇ mm), 20Wh/(L ⁇ mm), 25Wh/(L ⁇ mm), 30Wh/(L ⁇ mm), 35Wh/(L ⁇ mm), 40Wh/(L ⁇ mm ), 45Wh/(L ⁇ mm), 50Wh/(L ⁇ mm), 55Wh/(L ⁇ mm), 60Wh/(L ⁇ mm), 65Wh/(L ⁇ mm), 70Wh/(L ⁇ mm), 75Wh/(L ⁇ mm), 80Wh/(L ⁇ mm), 85Wh/(L ⁇ mm), 90Wh/(L ⁇ mm), 95Wh/(L ⁇ mm), 100Wh/(L ⁇ mm) or in other ranges formed by any two endpoints mentioned above.
  • the battery cell 10 further includes a pressure relief mechanism 105 .
  • the pressure relief mechanism 105 on the battery cell 10 has an important impact on the safety of the battery cell 10 . For example, when short circuit, overcharge, etc. occur, thermal runaway may occur inside the battery cell 10 and the pressure may rise suddenly. In this case, the internal pressure can be released outward by actuating the pressure relief mechanism 105 to prevent the battery cell 10 from exploding or catching fire, which is normal pressure relief.
  • the pressure relief mechanism 105 may be an element or component that is activated when the battery cell 10 reaches certain conditions.
  • the pressure relief mechanism 105 may be an element or component that is actuated to relieve the internal pressure and/or internal contents when the internal pressure or internal temperature of the battery cell 10 reaches a predetermined threshold. This threshold design varies based on design requirements.
  • the pressure relief mechanism 105 may take the form of an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, and may specifically adopt a pressure-sensitive component or structure.
  • the pressure relief mechanism 105 can be provided on the end cover 102 or on any wall of the housing 101 .
  • the volumetric energy density E of the battery cell 10 is 600Wh/L ⁇ E ⁇ 1000Wh/L.
  • the volumetric energy density of the battery cell 10 is E, where E is 610Wh/L, 620Wh/L, 630Wh/L, 640Wh/L, 650Wh/L, 660Wh/L, 670Wh/L , 680Wh/L, 690Wh/L, 700Wh/L, 710Wh/L, 720Wh/L, 730Wh/L, 740Wh/L, 750Wh/L, 760Wh/L, 770Wh/L, 780Wh/L, 790Wh/L, 800Wh /L, 810Wh/L, 820Wh/L, 830Wh/L, 840Wh/L, 850Wh/L, 880Wh/L, 870Wh/L, 880Wh/L, 890Wh/L, 900Wh/L, 910Wh/L, 920Wh/L , 930Wh/L,
  • the inventor found after in-depth research and extensive experiments that the appropriate volumetric energy density of the battery cell 10 is such that the volumetric energy density of the battery cell 10 is the minimum of the battery cell 10
  • the relationship between the thicknesses is within the safety design range of the battery cell 10 , which is more conducive to ensuring the safety of the battery cell 10 and reducing the overall structural deformation of the battery cell 10 .
  • T and E satisfy: 8Wh/(L ⁇ mm) ⁇ E/T ⁇ 80Wh/(L ⁇ mm).
  • T and E satisfy: 20Wh/(L ⁇ mm) ⁇ E/T ⁇ 80Wh/(L ⁇ mm).
  • This arrangement can ensure the safety of the battery cell 10, and the pressure relief mechanism 105 can release pressure normally after thermal runaway, but one of the shell 101 and the end cover 102 of the battery cell 10 is deformed, and the overall structural deformation of the battery cell 10 is not obvious.
  • T and E satisfy: 25Wh/(L ⁇ mm) ⁇ E/T ⁇ 40Wh/(L ⁇ mm).
  • the inventor found after in-depth research and extensive experiments that there is an appropriate relationship between the volumetric energy density of the battery cell 10 and the minimum thickness of the battery cell 10, which not only ensures that the battery cell After thermal runaway occurs in the body 10 , the pressure relief mechanism 105 can release pressure normally to ensure the safety of the battery cell 10 , and can also reduce the structural deformation of the battery cell 10 after thermal runaway, basically ensuring the structural integrity of the battery cell 10 .
  • the minimum thickness T of the battery cell 10 is 10mm ⁇ T ⁇ 100mm.
  • the minimum thickness T of the battery cell 10 is 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm or other ranges composed of any two endpoints mentioned above.
  • the minimum thickness T of the battery cell 10 is 20 mm ⁇ T ⁇ 60 mm.
  • the inventor found after in-depth research and extensive experiments that a suitable thickness of the battery cell 10 can ensure the overall strength and high volumetric energy density of the battery cell 10 .
  • the battery cell 10 thermally runs out of control and generates gas to form air pressure, causing the end cover 102 and the casing 101 of the battery cell 10 to deform more seriously.
  • the end cover 102 and the casing 101 deform and pull the ends.
  • connection between the cover 102 and the casing 101 reduces the strength of the connection, resulting in cracking of the connection and the risk of battery explosion; when the thickness of the battery cell 10 is thin, there is not enough space to install the pressure relief mechanism 105, and the battery The space utilization rate of the monomer 10 is low, which is not conducive to the improvement of energy density.
  • the battery cell 10 includes a housing 101 and an end cover 102.
  • the end of the housing 101 has an opening, and the end cover 102 is used to cover the opening.
  • the end cap 102 refers to a component that covers the opening of the case 101 to isolate the internal environment of the battery cell 10 from the external environment.
  • the shape of the end cap 102 may be adapted to the shape of the housing 101 to fit the housing 101 .
  • the end cap 102 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 102 is less likely to deform when subjected to extrusion and impact, so that the battery cell 10 can have higher durability. Structural strength and safety performance can also be improved.
  • the end cap 102 may be provided with functional components such as electrode terminals.
  • the end cap 102 can also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiment of the present application.
  • the case 101 is a component used to cooperate with the end cover 102 to form an internal environment of the battery cell 10 , wherein the formed internal environment can be used to accommodate electrode components, electrolytes and other components.
  • the casing 101 and the end cap 102 can be independent components, and an opening can be provided on the casing 101, and the end cap 102 covers the opening at the opening to form the internal environment of the battery cell 10.
  • the shape of the housing 101 can be determined according to the specific shape and size of the electrode assembly.
  • the housing 101 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiments of the present application.
  • the end cap 102 and the housing 101 are connected in a variety of ways, such as welding, upsetting, riveting, bonding, etc.
  • the end of the housing 101 along the second direction z has an opening, and the end cover 102 is used to cover the opening.
  • the end of the housing 101 along the thickness direction x has an opening, and the end cap 102 is used to cover the opening.
  • the electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator in the form of winding or lamination, wherein the gram capacity c 1 of the cathode material of the positive electrode sheet is ⁇ 170 mAh/g, such as nickel cobalt manganese, nickel cobalt aluminum, nickel cobalt manganese aluminum, lithium cobaltate, etc., and the gram capacity c 2 of the anode material of the negative electrode sheet is ⁇ 350 mAh/g, such as graphite, silicon-doped anode, lithium metal, etc.
  • the connection between the end cover 102 and the casing 101 is the weak point of the battery cell 10.
  • thermal runaway occurs inside the battery cell 10 and generates gas to form air pressure.
  • the casing 101 and end cover 102 of the battery cell 10 are easily deformed by force, thereby reducing the strength of the connection between the casing 101 and the end cover 102 , causing the connection between the casing 101 and the end cover 102 to crack earlier than the pressure relief mechanism 105 , unable to release pressure normally, leading to an extreme event of thermal runaway explosion.
  • the span of the connection becomes larger, and its strength is relatively weakened, making the risk of cracking more likely to occur.
  • connection strength and connection stability of the case 101 and the end cover 102 can be improved, and the case can be reduced in size.
  • the risk of cracking at the connection between the body 101 and the end cover 102 is ensured, and the pressure relief mechanism 105 is ensured to release pressure normally and the safety of the battery cell 10 is ensured.
  • the housing 101 is welded to the end cap 102 .
  • the shell 101 and the end cover 102 are welded using laser welding, penetration welding or ultrasonic welding.
  • the housing 101 is welded to the end cover 102.
  • the welding method can fix the positions of the housing 101 and the end cover 102, and can also increase the connection area between the housing 101 and the end cover 102. It increases the stability of the contact and improves the connection strength. Moreover, the welding process is convenient and controllable, which is conducive to large-scale preparation.
  • the melting point of the shell 101 is c
  • the minimum wall thickness of the shell 101 is d
  • c and d satisfy: c/d ⁇ 400°C/mm, optionally 400°C/mm ⁇ c /d ⁇ 7500°C/mm.
  • the wall thickness of the casing 101 does not include various functional areas that may be provided on the casing 101 (such as the liquid injection hole installation place, the electrode terminal installation place, the pressure relief mechanism installation place, and the casing opening).
  • the thickness of the step accommodating the end cover, the corner of the housing, etc.), that is, d refers to the thickness of the housing 101 except the functional area.
  • the minimum wall thickness is the minimum wall thickness d of the housing 101 .
  • the melting point of the shell 101 is c and the minimum wall thickness of the shell 101 is d, satisfying 400°C/mm ⁇ c/d ⁇ 7500°C/mm.
  • the melting point c of the housing 101 has an appropriate relationship with the minimum wall thickness d of the housing 101, ensuring the structural strength of the housing 101.
  • the melting point of the shell 101 is c and the minimum wall thickness of the shell 101 is d, so that c/d is 400°C/mm, 1000°C/mm, and 1500°C/mm. , 2000°C/mm, 2500°C/mm, 3000°C/mm, 3500°C/mm, 4000°C/mm, 4500°C/mm, 5000°C/mm, 5500°C/mm, 6000°C/mm, 6500°C/mm , 7000°C/mm, 7500°C/mm or other ranges composed of any two endpoints mentioned above.
  • the housing 101 may be made of materials with lower melting points, which can be understood as materials that are not resistant to high temperatures, such as polyester materials.
  • the housing 101 can also be made of some materials with relatively high melting points, which can be understood as high-temperature resistant materials, such as aluminum, steel or other metals.
  • the value of c/d can be adaptively reduced to reduce the space and weight occupied by the minimum wall thickness of the case 101, thereby increasing the volumetric energy density of the battery cell 10.
  • the inventor found after in-depth research and extensive experiments that since the battery cell 10 has a higher energy density, it releases more heat during thermal runaway. Therefore, the casing
  • the melting point c of 101 and the minimum wall thickness d of the shell 101 satisfy: c/d ⁇ 400°C/mm. Adjust the relationship between the melting point c of the shell 101 and the minimum wall thickness d of the shell 101 to ensure that the shell 101 has a certain Mechanical strength, thus reducing the risk of cracking of the battery cell 10 in other areas other than the pressure relief mechanism (such as the connection between the case 101 and the end cover 102) due to deformation of the battery cell 10.
  • FIG. 5 is a schematic structural diagram of a battery cell casing according to some embodiments of the present application.
  • the minimum wall thickness of the housing 101 is d, and the ratio of T and d satisfies: 6 ⁇ T/d ⁇ 500.
  • the ratio T/d of the minimum thickness T of the battery cell 10 to the minimum wall thickness d of the case 101 satisfies: 6, 50, 100, 150, 200, 250, 300, 350, 400 , 450, 500, or other ranges consisting of any two of the above endpoints.
  • the ratio of the minimum thickness T of the battery cell 10 to the minimum wall thickness d of the case 101 satisfies 10 ⁇ T/d ⁇ 100.
  • the greater the ratio of the minimum thickness T of the battery cell 10 to the minimum wall thickness d of the case 101 it means that the minimum wall thickness d of the case 101 is thinner, and the case 101 is flushed by the gas.
  • the lower the risk the more space and weight the case 101 occupies in the battery cell 10 .
  • the inventor found after in-depth research and extensive experiments that by setting an appropriate ratio of the minimum thickness T of the battery cell 10 to the minimum wall thickness d of the casing 101, the balance between Under the premise of thermal battery safety design requirements, the space and weight occupied by the housing 101 are reduced, and the volumetric energy density of the battery cell 10 is increased.
  • the minimum wall thickness d of the housing 101 is 0.2mm ⁇ d ⁇ 1.5mm.
  • the minimum wall thickness d of the housing 101 is 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm or other ranges composed of any two endpoints mentioned above.
  • the inventor found after in-depth research and extensive experiments that by setting the minimum wall thickness d of the housing 101 to 0.2 mm ⁇ d ⁇ 1.5 mm, on the premise of meeting the safety design, the reduction The minimum wall thickness d of the casing 101 can increase the volumetric energy density of the battery cell 10 .
  • the minimum thickness T of the battery cell 10 is 10mm ⁇ T ⁇ 40mm, and the minimum wall thickness d of the case 101 is 0.2mm ⁇ d ⁇ 0.6mm.
  • the inventors found after in-depth research and a large number of experiments that such a configuration can improve the volume energy density of the battery cell 10 while satisfying the safety design of the battery cell 10 and is conducive to miniaturization of the battery cell 10.
  • the minimum thickness T of the battery cell 10 is 40 mm ⁇ T ⁇ 60 mm, and the minimum wall thickness d of the case 101 is 0.6 mm ⁇ d ⁇ 1 mm.
  • the inventor found after in-depth research and extensive experiments that such an arrangement can increase the volumetric energy density of the battery cell 10 on the premise of meeting the safety design of the battery cell 10, and also It is beneficial to achieve miniaturization of the battery cell 10 .
  • the minimum thickness T of the battery cell 10 is 60 mm ⁇ T ⁇ 100 mm, and the minimum wall thickness d of the case 101 is 1 mm ⁇ d ⁇ 1.5 mm.
  • the inventor found after in-depth research and extensive experiments that there is an appropriate ratio between the minimum thickness T of the battery cell 10 and the minimum wall thickness d of the case 101, which can improve the battery cell quality.
  • the volume energy density of the body 10 is high, and the minimum wall thickness d of the housing 101 is relatively large, which can disperse the heat transferred to the housing 101, thereby reducing the risk of the housing 101 being punctured.
  • FIG. 6 is a schematic structural diagram of an end cover of a battery cell according to some embodiments of the present application.
  • the minimum thickness D of the end cap 102 is 1.5 mm ⁇ D ⁇ 4.0 mm.
  • the minimum thickness of the end cover 102 does not include the thickness of various functional areas that may be provided on the end cover 102 (such as the location of the liquid injection hole, the location of the electrode terminal installation, the installation location of the pressure relief mechanism, etc.). That is, D refers to the minimum thickness of the end cap 102 except the functional area.
  • the minimum thickness is the minimum thickness D of the end cap 102 .
  • the minimum thickness D of the end cap 102 is 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6 mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4.0mm or any two of the above other ranges composed of endpoints.
  • the minimum thickness D of the end cap 102 is 1.5 mm ⁇ D ⁇ 4.0 mm, which can meet the welding process requirements and ensure the welding strength after welding. If the thickness is thin, welding penetration will easily occur during welding and the process will be difficult. If the thickness is too thick, the welding process will be difficult, and more heat will be accumulated during the welding process, resulting in insufficient heat-affected welding strength.
  • the inventor found after in-depth research and extensive experiments that such an arrangement can ensure the strength of the end cover 102 and also increase the welding strength between the end cover 102 and the housing 101. Reduces the risk of cracking or breaking of welds.
  • the size of the battery cell 10 along the first direction y is W, W and T satisfy: 1mm/mm ⁇ W/T ⁇ 60mm/mm, and the size of the battery cell 10 in the first direction y maximum.
  • the battery cell 10 has a thickness (dimension along the thickness direction x), width (dimension along the first direction y), and height (dimension along the second direction z), wherein the battery cell 10 The width of the body 10 is greater than the height, and the height is greater than the thickness.
  • the dimension W of the battery cell 10 along the first direction y and the minimum thickness T of the battery cell 10 satisfy W/T of 1mm/mm, 5mm/mm, 10mm/mm, 15mm/mm, 20mm/mm, 25mm/mm, 30mm/mm, 35mm/mm, 40mm/mm, 45mm/mm, 50mm/mm, 55mm/mm, 60mm/mm or within other ranges formed by any two of the above endpoints.
  • the size of the battery cell 10 along the first direction y is W and the minimum thickness T of the battery cell 10 satisfies 1.25mm/mm ⁇ W/T ⁇ 30mm/mm.
  • the size of the battery cell 10 along the first direction y is W and the minimum thickness T of the battery cell 10 satisfies 1.5mm/mm ⁇ W/T ⁇ 20mm/mm.
  • the inventor found after in-depth research and extensive experiments that with such an arrangement, the size of the housing 101 can be reasonably designed, and the first battery can be appropriately increased while ensuring battery safety.
  • the size in the y direction allows the large surface of the casing 101 to have a larger heat transfer area. When thermal runaway occurs, the heat transferred to the casing 101 can be dispersed, reduce the accumulation of heat, and reduce the risk of the casing 101 being penetrated. risk.
  • a dimension W of the battery cell 10 along the first direction y is 100 mm ⁇ W ⁇ 600 mm.
  • the size W of the battery cell 10 along the first direction y is 100mm, 150mm, 200mm, 250mm, 300mm, 350mm, 400mm, 450mm, 500mm, 550mm, 600mm or any two of the above. other ranges composed of endpoints.
  • the inventor found after in-depth research and extensive experiments that a suitable size of the battery cell 10 along the first direction y can improve the space utilization within the battery cell 10 , thereby improving the space utilization of the battery cell 10 .
  • the volumetric energy density of the battery cell 10 is increased.
  • the size H of the battery cell 10 along the second direction z is H ⁇ 150 mm, and the second direction z is perpendicular to the first direction y.
  • the inventors discovered after in-depth research and a large number of experiments that the dimension H of the battery cell 10 along the second direction z is H ⁇ 150mm, so that the electrode assembly in the battery cell 10 can be fully infiltrated by the electrolyte, reducing the defect that the middle part of the electrode assembly is not easily infiltrated.
  • the battery cell 10 is a square battery cell 10 .
  • the safety effect of such prismatic battery cells 10 is better.
  • a second aspect of the present application also provides a battery, including the battery cell 10 of the first aspect of the present application.
  • a third aspect of the present application provides an electrical device, including the battery cell 10 of the first aspect of the present application or the battery of the second aspect of the present application.
  • the battery cell 10 or the battery is used to provide electric energy.
  • a square battery cell including a casing, electrode assembly, electrolyte and end cap.
  • the positive electrode sheet, separator film, and negative electrode sheet are stacked and wound in order to obtain the electrode assembly.
  • the electrode assembly into the case, add the electrolyte, close the end cap on the case, and after processes such as packaging, standing, formation, aging, etc., the battery cell is obtained, where the thickness T of the battery cell is 10mm, the width W is 300mm, the height H is 150mm, the volumetric energy density of the battery cell is 800Wh/L, and the E/T is 80.
  • the shell and end cover have no obvious deformation as "++";
  • the difference between the prismatic battery cells of Examples 2 to 8 and Comparative Examples 1 and 2 and Example 1 is the difference in volumetric energy density E and thickness T of the cell cells.
  • E and thickness T are the difference in volumetric energy density E and thickness T of the cell cells.
  • the difference between the prismatic battery cells of Examples 9 to 11 and Comparative Examples 3 and 4 and Example 2 is the thickness T and width W of the battery cells.
  • Table 2 For details, refer to Table 2 below.
  • the wall thickness d of the shell in Example 2 is 1 mm, and the melting point C of the shell is 700°C.
  • the difference between the prismatic battery cells of Examples 12 to 15 and Comparative Examples 5 and 6 and Example 2 is the difference in the wall thickness d of the case or the melting point C of the case.
  • Table 3 For details, refer to Table 3 below.
  • Examples 1 to 15 have all achieved good results, and the relationship between the volumetric energy density E and the minimum thickness T of the battery cell can be appropriately adjusted, and thermal runaway occurs inside the battery cell to generate gas and form air pressure.
  • the battery cell can normally release pressure at the pressure relief mechanism of the battery cell, thereby reducing the structural deformation of the battery cell and reducing the risk of cracking at the welds of the casing and end cover caused by the deformation of the battery cell. risk, further reducing the risk of battery explosion.
  • the relationship between the volumetric energy density E and the minimum thickness T of the battery cell is further optimized, and the deformation of the battery cell can be further reduced while ensuring the normal pressure relief of the battery cell. , improve the structural integrity of the battery cells.
  • the size of the casing can be reasonably designed to meet the safety of the battery cell, and the size of the battery cell along the first direction y, that is, the width W, can be extended within a suitable range, so that the casing
  • the large surface has a larger area, which can disperse the heat transferred to the shell when thermal runaway occurs, reducing heat accumulation and reducing the risk of the shell being penetrated.
  • the relationship between the melting point c of the shell and the wall thickness d of the shell is reasonably adjusted to ensure that the shell has a certain mechanical strength. It effectively reduces the deformation of the casing and reduces the risk of cracking at the welds between the casing and the end cover due to deformation of the battery cells.

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  • Engineering & Computer Science (AREA)
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Abstract

一种电池单体、电池及用电装置，电池单体(10)的体积能量密度为E，电池单体(10)的最小厚度为T，T和E满足:E≥600Wh/L，6Wh/(L·mm)≤E/T≤100Wh/(L·mm)；高能量密度的电池单体在发生热失控时，其产气速率和放热功率较高，通过调节电池单体的最小厚度，可以适应高能量密度电池单体的要求，保证电池单体的安全。

Description

电池单体、电池及用电装置 技术领域
本申请涉及电池生产技术领域，特别是涉及电池单体、电池及用电装置。
背景技术
电池单体广泛用于电子设备，例如手机、笔记本电脑、电瓶车、电动汽车、电动飞机、电动轮船、电动玩具汽车、电动玩具轮船、电动玩具飞机、电动工具和储能系统等等。电池单体可以包括镉镍电池单体、氢镍电池单体、锂离子电池单体、钠离子电池单体和二次碱性锌锰电池单体等。
在电池技术的发展中，如何提高电池单体的安全性，是电池技术中一个亟待解决的技术问题。
发明内容
本申请是鉴于上述课题而进行的，提供一种电池单体、电池及用电装置，旨在一定程度上能够提高电池单体的安全性。
为了达到上述目的，本申请的第一方面提供了一种电池单体，电池单体的体积能量密度为E，电池单体的最小厚度为T，T和E满足：E≥600Wh/L，6Wh/(L·mm)≤E/T≤100Wh/(L·mm)。
本申请提供的电池单体，电池单体的体积能量密度为E和电池单体的最小厚度为T满足：E≥600Wh/L，6Wh/(L·mm)≤E/T≤100Wh/(L·mm)。由于高能量密度的电池单体，在发生热失控时，其产气速率和放热功率均较高，因此通过调节电池单体的最小厚度，以适应高能量电池单体的要求，从而保证电池单体的安全。而且，适宜调节电池单体的体积能量密度与最小厚度之间的关系，在电池单体的内部发生热失控产气形成气压的情况下，电池单体能够在电池单体的泄压机构处正常泄压，从而降低电池单体的结构变形，减小因电池单体变形导致电池单体在处泄压机构之外的其 他区域(例如壳体和端盖连接处)发生开裂的风险，，进一步降低电池单体发生爆炸的风险。此外，适宜的调节电池单体的最小厚度，能够提高电池单体的空间利用率有利于能量密度的进一步提升。
根据本申请的一些实施例，电池单体的体积能量密度E为600Wh/L＜E≤1000Wh/L。
在这些可选的实施例中，适宜的电池单体的体积能量密度，使得电池单体的体积能量密度与电池单体的最小厚度之间的关系在电池单体的安全设计范围内，更有利于提高电池单体的安全性，且降低电池单体整体的结构形变。
根据本申请的一些实施例，T和E满足：8Wh/(L·mm)≤E/T≤80Wh/(L·mm)，可选地为20Wh/(L·mm)≤E/T≤80Wh/(L·mm)，更可选地为25Wh/(L·mm)≤E/T≤40Wh/(L·mm)。
在这些可选的实施例中，电池单体的体积能量密度与电池单体的最小厚度的适宜的关系，不仅保证电池单体发生热失控后，泄压机构能够正常的泄压，保证电池单体的安全，而且还能够降低热失控后电池单体的变形，基本保证电池单体的结构完整。
根据本申请的一些实施例，电池单体的最小厚度T为10mm≤T≤100mm，可选地为20mm≤T≤60mm。
在这些可选的实施例中，适宜的电池单体的厚度，能够保证电池单体的整体的强度和较高的体积能量密度。
根据本申请的一些实施例，电池单体包括壳体和端盖，壳体沿的端部具有开口，端盖用于盖合开口。
在这些可选的实施例中，通过调节电池单体的体积能量密度与电池单体的最小厚度的适宜的关系，提高壳体和端盖连接强度和连接稳定性，降低壳体与端盖连接处发生开裂的风险，保证电池单体的安全性。
根据本申请的一些实施例，壳体焊接于端盖。
在这些可选的实施例中，壳体焊接于端盖，焊接方式可以固定壳体和端盖的位置，且还能增大壳体和端盖之间的连接面积，增加接触的稳定性，提高连接强度，而且，焊接工艺便捷可控，利于规模化制备。
根据本申请的一些实施例，壳体的熔点为c，壳体的壁厚为d，c和d满 足：c/d≥400℃/mm，可选地为400℃/mm≤c/d≤7500℃/mm。
在这些可选的实施例中，由于电池单体具有较高的能量密度，热失控时所释放的热量也多，因此，使得壳体的熔点c与壳体的壁厚d满足：c/d≥400℃/mm，调节壳体的熔点c与壳体的壁厚d的关系，保证壳体具有一定的机械强度。有效降低壳体的变形，减小因电池单体变形导致电池单体在除泄压机构之外的其他区域(例如壳体和端盖连接处)发生开裂的风险。
根据本申请的一些实施例，壳体的最小壁厚为d，T和d之比满足：6T/d≤50，可选地为10≤T/d≤100。
在这些可选的实施例中，通过设置电池单体的最小厚度T与壳体的最小壁厚为d适宜的比值，以在兼顾热电池安全设计要求的前提下，减少壳体占用空间和重量，提高电池单体的体积能量密度。
根据本申请的一些实施例，壳体的最小壁厚d为0.2mm≤d≤1.5mm。
在这些可选的实施例中，通过设置壳体的最小壁厚d为0.2mm≤d≤1.5mm，满足安全设计的前提下，减少壳体最小壁厚，可提升电池单体的体积能量密度。
根据本申请的一些实施例，电池单体的最小厚度T为10mm≤T≤40mm，壳体的最小壁厚d为0.2mm≤d≤0.6mm。
在这些可选的实施例中，如此设置，在满足电池单体安全设计的前提下，提高电池单体的体积能量密度，并有利于实现电池单体的小型化。
根据本申请的一些实施例，电池单体的最小厚度T为40mm≤T≤60mm，壳体的最小壁厚d为0.6mm≤d≤1mm。
在这些可选的实施例中，如此设置，在满足电池单体安全设计的前提下，提高电池单体的体积能量密度，并有利于实现电池单体的小型化。
根据本申请的一些实施例，电池单体的最小厚度T为60mm≤T≤100mm，壳体的最小壁厚d为1mm≤d≤1.5mm
在这些可选的实施例中，适宜的电池单体的最小厚度T与壳体的最小壁厚d的关系，能够提高电池单体的体积能量密度，且壳体的最小壁厚的厚度较大能够分散传递至壳体的热量，以降低壳体被冲穿的风险。
根据本申请的一些实施例，端盖的最小厚度D为1.5mm≤D≤4.0mm。
在这些可选的实施例中，如此设置，能够保证端盖的强度，并且，还能够增加端盖与壳体的焊接强度，降低焊接处开裂或断裂的风险。
根据本申请的一些实施例，电池单体沿第一方向的尺寸为W，W与T满足：1mm/mm≤W/T≤60mm/mm，可选地为1.25mm/mm≤W/T≤30mm/mm，更可选地为1.5mm/mm≤W/T≤20mm/mm，电池单体在第一方向的尺寸最大。
在这些可选的实施例中，如此设置，能够合理设计壳体的尺寸，在满足电池安全性的前提下，可适当的增加第一方向的尺寸，从而使得壳体的大面具有较大的传热面积，在热失控发生时，能够分散传递至壳体的热量，降低热量的聚集，从而降低壳体被冲穿的风险。
根据本申请的一些实施例，电池单体沿第一方向的尺寸W为100mm≤W≤600mm。
在这些可选的实施例中，适宜的电池单体沿第一方向的尺寸，能够提高电池单体内的空间利用率，以提高电池单体的体积能量密度。
根据本申请的一些实施例，电池单体沿第二方向的尺寸H为H≤150mm，第二方向垂直于第一方向。
在这些可选的实施例中，电池单体沿第二方向的尺寸H为H≤150mm，使得电池单体中的电极组件能够被电解液充分浸润，降低电极组件中部不易被浸润的缺陷。
根据本申请的一些实施例，电池单体为方形电池单体。
在这些可选的实施例中，如此方形电池单体的安全效果更佳。
本申请的第二方面还提供一电池，包括本申请第一方面的电池单体。
本申请的第三方面提供一种用电装置，包括本申请第一方面的电池单体或本申请的第二方面的电池，电池单体或电池用于提供电能。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要 使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1为本申请一些实施例的车辆的结构示意图；
图2为本申请一些实施例的电池的分解结构示意图；
图3为本申请一些实施例的电池单体的分解结构示意图；
图4为本申请一些实施例的电池单体的结构示意图；
图5为本申请一些实施例的电池单体的壳体结构示意图；
图6为本申请一些实施例的电池单体的端盖结构示意图。
附图标记说明：
1000、车辆；
100、电池；200、控制器；300、马达；
10、电池单体；20、上盖；30、下盖；
101、壳体；102、端盖；103、电极组件；104、电极端子；105、泄压机构；
x厚度方向；y第一方向；z第二方向。
具体实施方式
为使本申请实施例的目的、技术方案和优点更加清楚，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b” 表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
除非另有定义，本申请所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本申请中在申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。本申请的说明书和权利要求书或上述附图中的术语“第一”、“第二”等是用于区别不同对象，而不是用于描述特定顺序或主次关系。
在本申请中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“附接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
本申请中术语“和/或”，仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本申请中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请的实施例中，相同的附图标记表示相同的部件，并且为了简洁，在不同实施例中，省略对相同部件的详细说明。应理解，附图示出的本申请实施例中的各种部件的厚度、长宽等尺寸，以及集成装置的整体厚度、长宽等尺寸仅为示例性说明，而不应对本申请构成任何限定。
本申请中出现的“多个”指的是两个以上(包括两个)。
本申请中，电池单体可以包括锂离子二次电池单体、锂离子一次电池单体、锂 硫电池单体、钠锂离子电池单体、钠离子电池单体或镁离子电池单体等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。电池单体一般按封装的方式分成三种：柱形电池单体、方体方形电池单体和软包电池单体，本申请实施例对此也不限定。
本申请的实施例所提到的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。例如，本申请中所提到的电池可以包括电池模块或电池包等。电池一般包括用于封装一个或多个电池单体的箱体。箱体可以一定程度上避免液体或其他异物影响电池单体的充电或放电。
电池单体包括电极组件和电解液，电极组件由正极片、负极片和隔离膜组成。电池单体主要依靠金属离子在正极片和负极片之间移动来工作。正极片包括正极集流体和正极活性物质层，正极活性物质层涂覆于正极集流体的表面，未涂敷正极活性物质层的集流体凸出于已涂覆正极活性物质层的集流体，未涂敷正极活性物质层的集流体层叠后作为正极极耳。以锂离子电池为例，正极集流体的材料可以为铝，正极活性物质可以为钴酸锂、n元金属锂化合物(n≥3)或锰酸锂等。负极片包括负极集流体和负极活性物质层，负极活性物质层涂覆于负极集流体的表面，未涂敷负极活性物质层的集流体凸出于已涂覆负极活性物质层的集流体，未涂敷负极活性物质层的集流体层叠后作为负极极耳。负极集流体的材料可以为铜，负极活性物质可以为石墨、金属锂、硅、硅氧化物、硅碳合金、锗单质、锗氧化物、碳锗合金、锡单质、锡氧化物或锡碳合金的一种或多种。隔离膜的材质可以为PP(polypropylene，聚丙烯)或PE(polyethylene，聚乙烯)等。此外，电极组件可以是卷绕式结构，也可以是叠片式结构，本申请实施例并不限于此。
随着新能源不断的发展，对电池的能量密度提出了越来越高的要求。在电池单体的体积能量密度≥600Wh/L时，低容量石墨-LFP体系已很难达成设计要求，因此，如正极包含高镍三元或锂钴，负极包含硅或锂金属等高容量的电极材料应运而生，而这些材料搭配设计的高比能体系的电池单体，在发生热失控时，无论是产气速率还是放热功率均是低比能体系的电池单体的数倍，甚至数百倍。因此高比能的电池单体的安全设计面临着一些新的挑战。发明人发现，电池单体的最小厚度为电池单体的设计的重要的参数，当电池单体的厚度尺寸过薄时，不利于体积能量密度的提升； 当电池单体的厚度尺寸过厚时，热失控产气形成的内部气压，容易使沿厚度方向的壳体形变过大而使得电池单体开裂，从而导致电池热失控爆炸的极端事件。
鉴于以上问题，发明人经过深入研究，提出了一种电池单体，电池单体的体积能量密度为E和电池单体的最小厚度为T满足：E≥600Wh/L，6Wh/(L·mm)≤E/T≤100Wh/(L·mm)。通过调节电池单体的最小厚度，以适应高能量电池的要求，从而保证电池的安全。本申请实施例描述的技术方案适用于电池单体、电池及用电装置。
电池单体可以应用于车辆、手机、便携式设备、笔记本电脑、轮船、航天器、电动玩具、电动工具和储能系统等等。车辆可以是燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等；航天器包括飞机、火箭、航天飞机和宇宙飞船等等；电动玩具包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等；电动工具包括金属切削电动工具、研磨电动工具、装配电动工具和铁道用电动工具，例如，电钻、电动砂轮机、电动扳手、电动螺丝刀、电锤、冲击电钻、混凝土振动器和电刨等等。本申请实施例对上述用电装置不做特殊限制。
以下实施例为了方便说明，以本申请一实施例的一种用电装置为车辆1000为例进行说明。
请参照图1，图1为本申请一些实施例提供的车辆1000的结构示意图。车辆1000可以为燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等。车辆1000的内部设置有电池100，电池100可以设置在车辆1000的底部或头部或尾部。电池100可以用于车辆1000的供电，例如，电池100可以作为车辆1000的操作电源。车辆1000还可以包括控制器200和马达300，控制器200用来控制电池100为马达300供电，例如，用于车辆1000的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池100不仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，代替或部分地代替燃油或天然气为车辆1000提供驱动动力。
请参照图2，图2为本申请一些实施例提供的电池100的爆炸图。电池100包括箱体和电池单体10。在一些实施例中，箱体可以包括上盖20和下盖30，上盖20 与下盖30相互盖合，上盖20和下盖30共同限定出用于容纳电池单体10的容纳空间。下盖30可以为一端开口的空心结构，上盖20可以为板状结构，上盖20盖合于下盖30的开口侧，以使上盖20与下盖30共同限定出容纳空间；上盖20和下盖30也可以是均为一侧开口的空心结构，上盖20的开口侧盖合于下盖30的开口侧。当然，上盖20和下盖30形成的箱体可以是多种形状，比如，圆柱体、长方体等。
在电池100中，电池单体10可以是多个，多个电池单体10之间可串联或并联或混联，混联是指多个电池单体10中既有串联又有并联。多个电池单体10之间可直接串联或并联或混联在一起，再将多个电池单体10构成的整体容纳于箱体内；当然，电池100也可以是多个电池单体10先串联或并联或混联组成电池模块形式，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体内。电池100还可以包括其他结构，例如，该电池100还可以包括汇流部件，用于实现多个电池单体10之间的电连接。
每个电池单体10可以为锂离子电池单体、锂硫电池单体、钠离子电池单体或镁离子电池单体，但不局限于此。电池单体10可呈圆柱体、扁平体、长方体或其它形状等。
请参照图3，图3为本申请一些实施例提供的电池单体10的分解结构示意图。电池单体10是指组成电池的最小单元。如图3，电池单体10包括有壳体101、端盖102、电极组件103、电极端子104以及其他的功能性部件。
端盖102是指盖合于壳体101的开口处以将电池单体10的内部环境隔绝于外部环境的部件。不限地，端盖102的形状可以与壳体101的形状相适应以配合壳体101。可选地，端盖102可以由具有一定硬度和强度的材质(如铝合金)制成，这样，端盖102在受挤压碰撞时就不易发生形变，使电池单体10能够具备更高的结构强度，安全性能也可以有所提高。端盖102上可以设置有如电极端子104等的功能性部件。电极端子104可以用于与电极组件103电连接，以用于输出或输入电池单体10的电能。端盖102的材质也可以是多种的，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。在一些实施例中，在端盖102的内侧还可以设置有绝缘构件，绝缘构件可以用于隔离壳体101内的电连接部件与端盖102，以降低短路的风险。示例性的，绝缘构件可以是塑料、橡胶等。
壳体101是用于配合端盖102以形成电池单体10的内部环境的组件，其中，形成的内部环境可以用于容纳电极组件103、电解液以及其他部件。壳体101和端盖102可以是独立的部件，可以于壳体101上设置开口，通过在开口处使端盖102盖合开口以形成电池单体10的内部环境。不限地，也可以使端盖102和壳体101一体化，具体地，端盖102和壳体101可以在其他部件入壳前先形成一个共同的连接面，当需要封装壳体101的内部时，再使端盖102盖合壳体101。壳体101可以是多种形状和多种尺寸的，例如长方体形、圆柱体形、六棱柱形等。具体地，壳体101的形状可以根据电极组件103的具体形状和尺寸大小来确定。壳体101的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。壳体101上也可以设置有如电极端子、注液孔等的功能性部件。
在一些实施例中，电池单体10还包括泄压机构105，泄压机构105用于在电池单体10的内部压力或温度达到阈值时泄放内部压力，可以设置在端盖102或壳体101上。
电极组件103是电池单体10中发生电化学反应的部件。壳体101内可以包含一个或更多个电极组件103。电极组件103主要由正极极片和负极极片卷绕形成，并且通常在正极极片与负极极片之间设有隔离膜。正极极片和负极极片具有活性物质的部分构成电极组件103的主体，正极极片和负极极片不具有活性物质的部分各自构成极耳。正极极耳和负极极耳可以共同位于主体的一端或是分别位于主体的两端。在电池的充放电过程中，正极活性物质和负极活性物质与电解液发生反应，极耳连接电极端子104以形成电流回路。
结合参阅图4，图4为本申请一些实施例的电池单体的结构示意图。
如图3和图4所示，本申请的一种电池单体10，电池单体10的体积能量密度为E，电池单体10的最小厚度为T，T和E满足：E≥600Wh/L，6Wh/(L·mm)≤E/T≤100Wh/(L·mm)。
电池单体10是组成电池的最小单元，其独自能够实现充放电的功能。电池单体10可以为方壳电池单体、软包电池单体或其它电池单体。电池单体10可呈扁平体、长方体或其它形状等，本申请以电池单体10为长方体为例。
电池单体10具有三个方向分别为厚度方向x、第一方向y和第二方向z，且电池单体10在厚度方向x上的尺寸小于在第二方向z的尺寸，第二方向z的尺寸小 于第一方向y的尺寸。电池单体10第二方向z的尺寸指的是电池单体10壳体101和端盖102在第二方向z占用的尺寸，不包括凸出端盖102或壳体101的电极端子104的尺寸。
在一些实施例中，厚度方向x、第一方向y和第二方向z两两垂直。
电池单体10在厚度方向上具有多个厚度尺寸时，其中最小值的厚度为电池单体10的最小厚度T。
电池单体10的体积能量密度的计算公式如下，
体积能量密度＝正极活性物质可发挥容量(A·h/kg)×正极活性物质质量(kg)×电池单体10标称电压(V)/电池单体10体积(L)
可以看出，增加电池单体10的体积能量密度主要包括：从电池化学体系出发，使用高电压或/和高容量电极材料如高镍三元层状材料、高容量富锂锰基材料、硅基负极材料及锂金属负极等；不改变电池化学体系，从结构设计出发，增加电池单体10单位质量或单位体积中活性物质占比。但是，随着体积能量密度的增加，对电池单体10的结构的安全设计也提出更高的要求，通常电池单体10外形尺寸的增加对电池单体10制造工艺影响最小，且电池单体10尺寸增加可以提高体积能量密度，其中，电池单体10的厚度一个较为敏感的参数，尤其对高比能化学体系的电池。当电池单体10的最小厚度尺寸过小时，不利于提升电池单体10的能量密度；当电池单体10的最小厚度尺寸过大时，电池单体10的壳体101和端盖102易受力变形，从而降低电池单体10除泄压机构105外的其他区域的强度(例如壳体101和端盖102的连接处的强度)，使得电池单体10除泄压机构105外的其他区域早于泄压机构105开裂，无法正常泄压，从而导致热失控爆炸的极端事件。
在这些可选的实施例中，电池单体10的体积能量密度为E和电池单体10的最小厚度为T满足：E≥600Wh/L，6Wh/(L·mm)≤E/T≤100Wh/(L·mm)，能够保证电池单体10的安全性，减低爆炸的风险。
在本申请的实施例中，在电池单体10的体积能量密度E≥600Wh/L的情况下，需要电池单体10的体积能量密度为E与电池单体10的最小厚度为T满足：E≥600Wh/L，6Wh/(L·mm)≤E/T≤100Wh/(L·mm)，从而保证高体积能量密度的电池单体10的安全性。
本申请提供的电池单体10，发明人在经过深入的研究和大量的实验之后发现，电池单体10的体积能量密度为E和电池单体10的最小厚度为T满足：E≥600Wh/L，6Wh/(L·mm)≤E/T≤100Wh/(L·mm)。由于高能量密度的电池单体10，在发生热失控时，其产气速率和放热功率均较高，因此通过调节电池单体10的最小厚度，以适应高能量电池单体10的要求，从而保证电池单体10的安全。而且，适宜调节电池单体10的体积能量密度与最小厚度之间的关系，在电池单体10的内部发生热失控产气形成气压的情况下，电池单体10能够在电池单体的泄压机构处正常泄压，从而降低电池单体10的结构变形，减小因电池单体10变形导致电池单体10在除泄压机构之外的其他区域(例如壳体101和端盖102连接处)发生开裂的风险，进一步降低电池发生爆炸的风险。此外，适宜的调节电池单体10的最小厚度，能够提高电池单体10的空间利用率，有利于能量密度的进一步提升。
在本申请的一些实施例中，电池单体10的体积能量密度为E，其中E为600Wh/L、650Wh/L、700Wh/L、750Wh/L、800Wh/L、850Wh/L、900Wh/L、950Wh/L、1000Wh/L、1050Wh/L、1100Wh/L、1150Wh/L、1200Wh/L、1250Wh/L、1300Wh/L、1350Wh/L、1400Wh/L、1450Wh/L、1500Wh/L……等等，或在由上述的任意两个端点所组成的其它范围内。
在本申请的一些实施例中，电池单体10的体积能量密度为E，电池单体10的最小厚度为T，T和E满足E/T为6Wh/(L·mm)、10Wh/(L·mm)、15Wh/(L·mm)、20Wh/(L·mm)、25Wh/(L·mm)、30Wh/(L·mm)、35Wh/(L·mm)、40Wh/(L·mm)、45Wh/(L·mm)、50Wh/(L·mm)、55Wh/(L·mm)、60Wh/(L·mm)、65Wh/(L·mm)、70Wh/(L·mm)、75Wh/(L·mm)、80Wh/(L·mm)、85Wh/(L·mm)、90Wh/(L·mm)、95Wh/(L·mm)、100Wh/(L·mm)或在由上述的任意两个端点所组成的其它范围内。
在本申请的一些实施例中，电池单体10还包括泄压机构105。电池单体10上的泄压机构105对电池单体10的安全性有着重要影响。例如，当发生短路、过充等现象时，可能会导致电池单体10内部发生热失控从而压力骤升。这种情况下通过泄压机构105致动可以将内部压力向外释放，以防止电池单体10爆炸、起火，即为正常泄压。泄压机构105可以是在电池单体10达到一定条件时致动的元件或部件。示例性地，泄压机构105可以是在电池单体10的内部压力或内部温度达到预定阈值时致动以 泄放内部压力和/或内部物质的元件或部件。该阈值设计根据设计需求不同而不同。泄压机构105可以采用诸如防爆阀、气阀、泄压阀或安全阀等的形式，并可以具体采用压敏元件或构造。
可以理解的，泄压机构105可以设置在端盖102上，也可以设置在壳体101的任意一个壁上。
根据本申请的一些实施例，电池单体10的体积能量密度E为600Wh/L＜E≤1000Wh/L。
在本申请的一些实施例中，电池单体10的体积能量密度为E，其中E为610Wh/L、620Wh/L、630Wh/L、640Wh/L、650Wh/L、660Wh/L、670Wh/L、680Wh/L、690Wh/L、700Wh/L、710Wh/L、720Wh/L、730Wh/L、740Wh/L、750Wh/L、760Wh/L、770Wh/L、780Wh/L、790Wh/L、800Wh/L、810Wh/L、820Wh/L、830Wh/L、840Wh/L、850Wh/L、880Wh/L、870Wh/L、880Wh/L、890Wh/L、900Wh/L、910Wh/L、920Wh/L、930Wh/L、940Wh/L、950Wh/L、990Wh/L、970Wh/L、980Wh/L、990Wh/L、1000Wh/L或在由上述的任意两个端点所组成的其它范围内。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，适宜的电池单体10的体积能量密度，使得电池单体10的体积能量密度与电池单体10的最小厚度之间的关系在电池单体10的安全设计范围内，更有利于保证电池单体10的安全性，且降低电池单体10整体结构形变。
根据本申请的一些实施例，T和E满足：8Wh/(L·mm)≤E/T≤80Wh/(L·mm)。
可选地，T和E满足：20Wh/(L·mm)≤E/T≤80Wh/(L·mm)。如此设置，能够保证电池单体10的安全性，且热失控后泄压机构105能够正常的泄压，但是电池单体10的壳体101和端盖102一者有变形，电池单体10的整体结构变形不明显。
更可选地，T和E满足：25Wh/(L·mm)≤E/T≤40Wh/(L·mm)。如此设置，能够保证电池单体10的安全性，且热失控后泄压机构105能够正常的泄压，保证电池单体10的整体结构。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，电池单体10的体积能量密度与电池单体10的最小厚度之间具有适宜的关系，不 仅保证电池单体10发生热失控后，泄压机构105能够正常的泄压，保证电池单体10的安全，还能够降低热失控后电池单体10的结构变形，基本保证电池单体10的结构完整。
根据本申请的一些实施例，如图3和4所示，电池单体10的最小厚度T为10mm≤T≤100mm。
在本申请的一些实施例中，电池单体10的最小厚度T为10mm、15mm、20mm、25mm、30mm、35mm、40mm、45mm、50mm、55mm、60mm、65mm、70mm、75mm、80mm、85mm、90mm、95mm、100mm或在由上述的任意两个端点所组成的其它范围内。
可选地，电池单体10的最小厚度T为20mm≤T≤60mm。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，适宜的电池单体10的厚度，能够保证电池单体10的整体的强度和较高的体积能量密度。在电池单体10的厚度较厚时，电池单体10热失控产气以形成气压，使得电池单体10的端盖102和壳体101变形较为严重，端盖102和壳体101变形拉扯端盖102和壳体101的连接处，使得连接处强度降低，从而导致连接处开裂，发生电池爆炸的风险；在电池单体10的厚度较薄时，无足够空间安装泄压机构105，且电池单体10的空间利用率低，不利于能量密度的提升。
根据本申请的一些实施例，如图3和图4所示，电池单体10包括壳体101和端盖102，壳体101的端部具有开口，端盖102用于盖合开口。
端盖102是指盖合于壳体101的开口处，以将电池单体10的内部环境隔绝于外部环境的部件。不限地，端盖102的形状可以与壳体101的形状相适应以配合壳体101。可选地，端盖102可以由具有一定硬度和强度的材质(如铝合金)制成，这样，端盖102在受挤压碰撞时就不易发生形变，使电池单体10能够具备更高的结构强度，安全性能也可以有所提高。端盖102上可以设置有如电极端子等的功能性部件。端盖102的材质也可以是多种的，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。
壳体101是用于配合端盖102，以形成电池单体10的内部环境的组件，其中，形成的内部环境可以用于容纳电极组件、电解液以及其他部件。壳体101和端盖102可以是独立的部件，可以于壳体101上设置开口，通过在开口处使端盖102盖合开 口以形成电池单体10的内部环境。具体地，壳体101的形状可以根据电极组件的具体形状和尺寸大小来确定。壳体101的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。
在本申请的一些实施例中，端盖102与壳体101的连接方式有多种，例如：焊接、镦封、铆接、粘接等等。
示例性地，壳体101沿第二方向z的端部具有开口，端盖102用于盖合开口。
示例性地，壳体101沿厚度方向x的端部具有开口，端盖102用于盖合开口。
可选地，电极组件由正极片、负极片和隔离膜通过卷绕或者叠片的形式构成，其中正极片的阴极材料的克容量c 1≥170mAh/g，如镍钴锰、镍钴铝、镍钴锰铝、钴酸锂等，负极片的阳极材料的克容量c 2≥350mAh/g，如石墨、掺硅阳极、锂金属等。
在本申请的实施例中，端盖102与壳体101的连接处为电池单体10的薄弱处，在电池单体10发生热失控时，电池单体10内部发生热失控产气形成气压，电池单体10的壳体101和端盖102易受力变形，从而降低壳体101和端盖102的连接处的强度，使得壳体101和端盖102的连接处早于泄压机构105开裂，无法正常泄压，从而导致热失控爆炸的极端事件。而且，随着电池单体10厚度的增加，连接处的跨度较大，其强度也相对减弱，更容易发生开裂的风险。
在这些可选的实施例中，通过调节电池单体10的体积能量密度与电池单体10的最小厚度的适宜的关系，能够提高壳体101和端盖102连接强度和连接稳定性，降低壳体101和端盖102的连接处发生开裂的风险，保证泄压机构105正常泄压，保证电池单体10的安全性。
根据本申请的一些实施例，壳体101焊接于端盖102。
可选地，壳体101和端盖102焊接方式采用激光焊接、穿透焊接或超声波焊接等方式。
在这些可选的实施例中，壳体101焊接于端盖102，焊接方式可以固定壳体101和端盖102的位置，且还能增大壳体101和端盖102之间的连接面积，增加接触的稳定性，提高连接强度，而且，焊接工艺便捷可控，利于规模化制备。
根据本申请的一些实施例，壳体101的熔点为c，壳体101的最小壁厚为d，c和d满足：c/d≥400℃/mm，可选地为400℃/mm≤c/d≤7500℃/mm。
特别需要说明的是，此处壳体101的壁厚不包括可能设置在壳体101上的各功能区(比如注液孔设置处、电极端子安装处、泄压机构安装处、壳体开口处容纳端盖的台阶、壳体拐角等)的厚度，即d指壳体101的除功能区以外的厚度。
在本申请的一些实施例中，壳体101具有多个壁厚尺寸时，其中最小值的壁厚为壳体101的最小壁厚d。
可选地，壳体101的熔点壳体101的熔点为c与壳体101的最小壁厚为d满足400℃/mm≤c/d≤7500℃/mm。如此设置，壳体101的熔点为c与壳体101的最小壁厚为d具有适宜的关系，保证壳体101的结构强度。
在本申请的一些实施例中，壳体101的熔点壳体101的熔点为c与壳体101的最小壁厚为d满足c/d为400℃/mm、1000℃/mm、1500℃/mm、2000℃/mm、2500℃/mm、3000℃/mm、3500℃/mm、4000℃/mm、4500℃/mm、5000℃/mm、5500℃/mm、6000℃/mm、6500℃/mm、7000℃/mm、7500℃/mm或在由上述的任意两个端点所组成的其它范围内。
在本申请的一些实施例中，壳体101可以采用一些熔点较低的材质，可以理解为不耐高温的材质，例如聚酯材料。当然，壳体101可也可采用一些相对熔点较高的材质，可以理解为耐高温的材质，例如铝、钢或其它金属。当壳体101采用耐高温的材质时，c/d的值可以适应性地减小，以降低壳体101的最小壁厚占用的空间和重量，从而提高电池单体10的体积能量密度。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，由于电池单体10具有较高的能量密度，热失控时所释放的热量也多，因此，使得壳体101的熔点c与壳体101的最小壁厚d满足：c/d≥400℃/mm，调节壳体101的熔点c与壳体101的最小壁厚d的关系，保证壳体101具有一定的机械强度，如此减小因电池单体10变形导致电池单体10在除泄压机构之外的其他区域(例如壳体101和端盖102连接处)发生开裂的风险。
结合参阅图5，图5为本申请一些实施例的电池单体的壳体结构示意图。
根据本申请的一些实施例，如图4和图5所示，壳体101的最小壁厚为d，T和d之比满足：6≤T/d≤500。
在本申请的一些实施例中，电池单体10的最小厚度T与壳体101的最小壁厚d之比T/d满足：6、50、100、150、200、250、300、350、400、450、500或在由上述的任意两个端点所组成的其它范围内。
可选地，电池单体10的最小厚度T与壳体101的最小壁厚d之比满足为10≤T/d≤100。
在本申请的实施例中，电池单体10的最小厚度T与壳体101的最小壁厚为d的比值越大，说明壳体101的最小壁厚为d越薄，壳体101被气体冲穿的风险越高；电池单体10的最小厚度T与壳体101的最小壁厚为d的比值越小，说明壳体101的最小壁厚为d越厚，壳体101被气体冲穿的风险越低，但壳体101在电池单体10中占用的空间和重量也越大。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，通过设置电池单体10的最小厚度T与壳体101的最小壁厚为d适宜的比值，以在兼顾热电池安全设计要求的前提下，减少壳体101占用空间和重量，提高电池单体10的体积能量密度。
根据本申请的一些实施例，如图4和图5所示，壳体101的最小壁厚d为0.2mm≤d≤1.5mm。
在本申请的一些实施例中，壳体101的最小壁厚d为0.2mm、0.3mm、0.4mm、0.5mm、0.6mm、0.7mm、0.8mm、0.9mm、1mm、1.1mm、1.2mm、1.3mm、1.4mm、1.5mm或在由上述的任意两个端点所组成的其它范围内。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，通过设置壳体101的最小壁厚d为0.2mm≤d≤1.5mm，满足安全设计的前提下，减少壳体101的最小壁厚d，可提升电池单体10的体积能量密度。
根据本申请的一些实施例，电池单体10的最小厚度T为10mm≤T≤40mm，壳体101的最小壁厚d为0.2mm≤d≤0.6mm。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，如此设置，在满足电池单体10安全设计的前提下，提高电池单体10的体积能量密度，并有利于实现电池单体10小型化。
根据本申请的另一些实施例，电池单体10的最小厚度T为40mm≤T≤60mm，壳体101的最小壁厚d为0.6mm≤d≤1mm。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，如此设置，在满足电池单体10安全设计的前提下，可提高电池单体10的体积能量密度，并有利于实现电池单体10小型化。
根据本申请的又一些实施例，电池单体10的最小厚度T为60mm≤T≤100mm，壳体101的最小壁厚d为1mm≤d≤1.5mm。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，电池单体10的最小厚度T与壳体101的最小壁厚d之间具有适宜比例，可提高电池单体10的体积能量密度，且壳体101的最小壁厚d的厚度较大能够分散传递至壳体101的热量，从而降低壳体101被冲穿的风险。
结合参阅图6，图6为本申请一些实施例的电池单体的端盖结构示意图。
根据本申请的一些实施例，如图4至图6所示，端盖102的最小厚度D为1.5mm≤D≤4.0mm。
特别需要说明的是，此处端盖102的最小厚度不包括可能设置在端盖102上的各功能区(比如注液孔设置处、电极端子安装处、泄压机构安装处等)的厚度，即D指端盖102的除功能区以外的最小厚度。
在本申请的一些实施例中，端盖102具有多个厚度尺寸时，其中最小值的厚度为端盖102的最小厚度D。
在本申请的一些实施例中，端盖102的最小厚度D为1.5mm、1.6mm、1.7mm、1.8mm、1.9mm、2mm、2.1mm、2.2mm、2.3mm、2.4mm、2.5mm、2.6mm、2.7mm、2.8mm、2.9mm、3mm、3.1mm、3.2mm、3.3mm、3.4mm、3.5mm、3.6mm、3.7mm、3.8mm、3.9mm、4.0mm或在由上述的任意两个端点所组成的其它范围内。
在本申请的一些实施例中，端盖102的最小厚度D为1.5mm≤D≤4.0mm能够满足焊接工艺要求，能够保证焊接后的焊接强度。若厚度较薄，焊接时容易发生焊穿的情况，工艺难度大，若厚度过厚，焊接工艺难度大，且焊接过程积蓄的热量较多，导致热影响焊接强度不足。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，如此设置，能够保证端盖102的强度，并且，还能够增加端盖102与壳体101的焊接强度，降低焊接处开裂或断裂的风险。
根据本申请的一些实施例，电池单体10沿第一方向y的尺寸为W，W与T 满足：1mm/mm≤W/T≤60mm/mm，电池单体10在第一方向y的尺寸最大。
在本申请的一些实施例中，电池单体10具有厚度(沿厚度方向x的尺寸)、宽度(沿第一方向y的尺寸)、高度(沿第二方向z的尺寸)，其中，电池单体10的宽度大于高度，高度大于厚度。
在本申请的一些实施例中，电池单体10沿第一方向y的尺寸为W和电池单体10的最小厚度T满足W/T为1mm/mm、5mm/mm、10mm/mm、15mm/mm、20mm/mm、25mm/mm、30mm/mm、35mm/mm、40mm/mm、45mm/mm、50mm/mm、55mm/mm、60mm/mm或在由上述的任意两个端点所组成的其它范围内。
可选地，电池单体10沿第一方向y的尺寸为W和电池单体10的最小厚度T满足1.25mm/mm≤W/T≤30mm/mm。
更可选地，电池单体10沿第一方向y的尺寸为W和电池单体10的最小厚度T满足1.5mm/mm≤W/T≤20mm/mm。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，如此设置，能够合理设计壳体101的尺寸，在满足电池安全性的前提下，可适当的增加第一方向y的尺寸，从而使得壳体101的大面具有较大的传热面积，在热失控发生时，能够分散传递至壳体101的热量，降低热量的聚集，降低壳体101被冲穿的风险。
根据本申请的一些实施例，电池单体10沿第一方向y的尺寸W为100mm≤W≤600mm。
在本申请的一些实施例中，电池单体10沿第一方向y的尺寸W为100mm、150mm、200mm、250mm、300mm、350mm、400mm、450mm、500mm、550mm、600mm或在由上述的任意两个端点所组成的其它范围内。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，适宜的电池单体10沿第一方向y的尺寸，能够提高电池单体10内的空间利用率，从而实现电池单体10的体积能量密度增加。
根据本申请的一些实施例，如图4至图6所示，电池单体10沿第二方向z的尺寸H为H≤150mm，第二方向z垂直于第一方向y。
在这些可选的实施例中，发明人在经过深入的研究和大量的实验之后发现，电池单体10沿第二方向z的尺寸H为H≤150mm，使得电池单体10中的电极组 件可被电解液充分浸润，降低电极组件中部不易被浸润的缺陷。
根据本申请的一些实施例，电池单体10为方形电池单体10。
在这些可选的实施例中，如此方形电池单体10的安全效果更佳。
本申请的第二方面还提供一电池，包括本申请第一方面的电池单体10。
本申请的第三方面提供一种用电装置，包括本申请第一方面的电池单体10或本申请的第二方面的电池，电池单体10或电池用于提供电能。
实施例
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
实施例1
设计方形电池单体，包括壳体、电极组件、电解液和端盖，将正极极片、隔离膜、负极极片按顺序堆叠并卷绕，得到电极组件。将电极组件放入壳体中，加入电解液，将端盖盖合在壳体上，经封装、静置、化成、老化等工序后，得到电池单体，其中，电池单体的厚度T为10mm，宽度W为300mm，高度H为150mm，电池单体的体积能量密度为800Wh/L，满足E/T为80。
电池安全测试：
制作试验电池单体时，将30mm×30mm×1mm(长×宽×厚)加热片粘贴在电极组件表面，加热片的正负导线从电池单体的端盖预设的出线孔引出，小孔位置进行结构密封处理，密封位置强度不低于电池单体泄压机构的开启所需强度。试验电池单体制作完毕之后，将电池单体充电至满电态(100％SOC)。试验的环境温度：室温(25±5℃)；将加热片的导线接入直流电源中，使加热片的输出功率在300±50w的条件下，加热触发至电池单体发生热失控，探究电池单体的热失控行为特征，
其中，壳体和端盖无明显变形为“++”；
壳体和端盖一者有变形，壳体和端盖的焊缝处未发生开裂为“+”；
壳体和端盖都有变形，壳体和端盖的焊缝处未发生开裂为“－”；
壳体和端盖都有变形，壳体和端盖的焊缝处发生开裂为“－－”。
实施例2～8和对比例1和2的方形电池单体与实施例1的区别为池单体的体积能量密度E和厚度T的差异，具体参照按照下表1。
表1实施例1～8与对比例1和2的结果
Figure PCTCN2022120349-appb-000001
实施例9～11和对比例3和4的方形电池单体与实施例2的区别为电池单体的厚度T和宽度W的差异，具体参照按照下表2。
表2实施例2、9～11与对比例3和4的结果
Figure PCTCN2022120349-appb-000002
实施例2中的壳体的壁厚d为1mm，壳体的熔点C为700℃，
实施例12～15和对比例5和6的方形电池单体与实施例2的区别为壳体的壁厚d或壳体的熔点C的差异，具体参照按照下表3。
表3实施例2、12～15与对比例5和6的结果
Figure PCTCN2022120349-appb-000003
根据上述结果可知，实施例1至15，均取得了良好的效果，适宜调节电池单体的体积能量密度E与最小厚度T之间的关系，在电池单体的内部发生热失控产气形成气压的情况下，电池单体能够在电池单体的泄压机构处正常泄压，从而降低电池单体的结构变形，减小因电池单体变形导致壳体和端盖的焊缝处发生开裂的风险，进一步降低电池发生爆炸的风险。参见实施例2、3、6和8，进一步优化电池单体的体积能量密度E与最小厚度T之间的关系，在保证电池单体正常泄压的前提下，能够进一步降低电池单体的变形，提高电池单体的结构完整。
对比例1和2，当电池单体的最小厚度T尺寸过小时，不利于提升单体单体的体积能量密度E，而且，无足够空间设置泄压机构，泄压面积过小，导致泄压能力不足，电池单体壳体烧破。当电池单体的最小厚度T尺寸过大时，电池单体的壳体和端盖易受力变形，从而降低壳体和端盖的焊缝处的强度，使得壳体和端盖的焊缝处早于泄压机构开裂，无法正常泄压，从而导致热失控爆炸的极端事件。
实施例9至11，能够合理设计壳体的尺寸，能够满足电池单体的安全性，而且，在适宜的范围内延长电池单体沿第一方向y的尺寸，也即宽度W，使得壳体的大面具有较大的面积，在热失控发生时，能够分散传递至壳体的热量，降低热量的聚集，降低壳体被冲穿的风险。
实施例12至15，合理调节壳体的熔点c与壳体的壁厚d的关系，保证壳体具有一定的机械强度。有效降低壳体的变形，减小因电池单体变形导致壳体和端盖的焊缝处发生开裂的风险。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (17)

  1. 一种电池单体，所述电池单体的体积能量密度为E，所述电池单体的最小厚度为T，T和E满足：E≥600Wh/L，6Wh/(L·mm)≤E/T≤100Wh/(L·mm)。
  2. 根据权利要求1所述的电池单体，其中，
    所述电池单体的体积能量密度E为600Wh/L＜E≤1000Wh/L。
  3. 根据权利要求1或2所述的电池单体，其中，
    T和E满足：8Wh/(L·mm)≤E/T≤80Wh/(L·mm)，可选地为20Wh/(L·mm)≤E/T≤80Wh/(L·mm)，更可选地为25Wh/(L·mm)≤E/T≤40Wh/(L·mm)。
  4. 根据权利要求1至3任一项所述的电池单体，其中，
    所述电池单体的最小厚度T为10mm≤T≤100mm，可选地为20mm≤T≤60mm。
  5. 根据权利要求1所述的电池单体，其中，
    所述电池单体包括壳体和端盖，所述壳体的端部具有开口，所述端盖用于盖合所述开口。
  6. 根据权利要求5所述的电池单体，其中，
    所述壳体焊接于端盖。
  7. 根据权利要求5或6所述的电池单体，其中，
    所述壳体的熔点为c，所述壳体的最小壁厚为d，c和d满足：c/d≥400℃/mm，可选地为400℃/mm≤c/d≤7500℃/mm。
  8. 根据权利要求5或6所述的电池单体，其中，
    所述壳体的最小壁厚为d，T和d之比满足：6≤T/d≤500，可选地为10≤T/d≤100。
  9. 根据权利要求5至8任一项所述的电池单体，其中，
    所述壳体的最小壁厚d为0.2mm≤d≤1.5mm。
  10. 根据权利要求9所述的电池单体，其中，
    所述电池单体满足下述(1)～(3)中的一个或几个：
    (1)所述电池单体的最小厚度T为10mm≤T≤40mm，所述壳体的最小壁厚d为0.2mm≤d≤0.6mm；
    (2)所述电池单体的最小厚度T为40mm≤T≤60mm，所述壳体的最小壁厚d为 0.6mm≤d≤1mm；
    (3)所述电池单体的最小厚度T为60mm≤T≤100mm，所述壳体的最小壁厚d为1mm≤d≤1.5mm。
  11. 根据权利要求5或6所述的电池单体，其中，
    所述端盖的最小厚度D为1.5mm≤D≤4.0mm。
  12. 根据权利要求1所述的电池单体，其中，
    所述电池单体沿第一方向的尺寸为W，W与T满足：1mm/mm≤W/T≤60mm/mm，可选地为1.25mm/mm≤W/T≤30mm/mm，更可选地为1.5mm/mm≤W/T≤20mm/mm，所述电池单体在所述第一方向的尺寸最大。
  13. 根据权利要求12所述的电池单体，其中，
    所述电池单体沿所述第一方向的尺寸W为100mm≤W≤600mm。
  14. 根据权利要求12所述的电池单体，其中，
    所述电池单体沿第二方向的尺寸H为H≤150mm，所述第二方向垂直于所述第一方向。
  15. 根据权利要求1所述的电池单体，其中，
    所述电池单体为方形电池单体。
  16. 一种电池，包括多个根据权利要求1至15任一项所述的电池单体。
  17. 一种用电装置，包括多个根据权利要求1至15任一项所述的电池单体或根据权利要求16所述的电池，所述电池单体或所述电池用于提供电能。
PCT/CN2022/120349 2022-09-21 2022-09-21 电池单体、电池及用电装置 WO2024060093A1 (zh)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080107958A1 (en) * 2002-03-07 2008-05-08 Unibatt Ltd. Chargeable Electrochemical Cell
CN107004900A (zh) * 2014-12-09 2017-08-01 日本碍子株式会社 搭载有电池的设备
CN107275669A (zh) * 2016-03-31 2017-10-20 日立麦克赛尔株式会社 锂二次电池
JP2019179586A (ja) * 2018-03-30 2019-10-17 マクセルホールディングス株式会社 扁平型電池

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080107958A1 (en) * 2002-03-07 2008-05-08 Unibatt Ltd. Chargeable Electrochemical Cell
CN107004900A (zh) * 2014-12-09 2017-08-01 日本碍子株式会社 搭载有电池的设备
CN107275669A (zh) * 2016-03-31 2017-10-20 日立麦克赛尔株式会社 锂二次电池
JP2019179586A (ja) * 2018-03-30 2019-10-17 マクセルホールディングス株式会社 扁平型電池

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