Battery cells, battery devices, and power-consuming devices

Abstract

The present application discloses a battery cell, a battery device, and an electrical device. The size of the battery cell in the first direction is 80-130 mm; the size in the second direction is 200-350 mm; the ratio of the size in the second direction to the size in the first direction is 1.5-4.4; the positive electrode connector includes a first main body and a first bent portion arranged at an angle; the size of the first main body in the second direction is 1.5-3.0 mm, and the size of the first bent portion in the first direction is 1.5-3.0 mm; the negative electrode connector includes a second main body and a second bent portion arranged at an angle; the size of the second main body in the second direction is 1.2-2.5 mm, and the size of the second bent portion in the first direction is 1.2-2.5 mm. The technical solution structure of the present application is more reasonable, further improving the energy density and fast charging reliability of the battery.

Description

[0001] This application claims priority to PCT international application PCT / CN2025 / 077647, entitled “Battery Cell, Battery Device, and Electrical Device,” filed on February 17, 2025, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery cell, a battery device, and an electrical device. Background Art

[0003] In recent years, as the application scope of batteries has become wider and wider, batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.

[0004] With the widespread application of batteries, higher requirements are placed on the energy density and fast charging reliability of batteries. However, the structure of battery cells is not reasonable, which means that the energy density and fast charging reliability of batteries need to be further improved. Summary of the Invention

[0005] This application is made in view of the above-mentioned problems, and its purpose is to provide a battery cell, a battery device, and an electrical device with a more reasonable structure, which further improves the energy density and fast charging reliability of the battery.

[0006] In a first aspect, the present application provides a battery cell, wherein the size of the battery cell in a first direction is 80 to 130 mm; the size of the battery cell in a second direction is 200 to 350 mm; and the ratio of the size of the battery cell in the second direction to the size of the battery cell in the first direction is 1.5 to 4.4. The battery cell comprises a housing, an electrode assembly, a positive electrode connector, and a negative electrode connector. The housing comprises a shell, and a top cover covering a port of the shell in the first direction, the top cover being provided with a positive electrode column and a negative electrode column along the second direction, and the electrode assembly being provided in the housing.

[0007] The electrode assembly includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked in a third direction, and positive electrode tabs and negative electrode tabs located at both side ends of the electrode assembly in a second direction; wherein the positive electrode active material of the positive electrode sheets includes a lithium-containing phosphate, and the negative electrode active material of the negative electrode sheets includes graphite;

[0008] The positive electrode connector includes a first main portion and a first bent portion arranged at an angle. The first bent portion is provided with a first welding hole for the positive electrode column to pass through and connect, and a first annular welding portion is formed between the first welding hole and the positive electrode column. The first main portion is electrically connected to the positive electrode tab. The dimension of the first main portion in the second direction is 1.5-3.0 mm, and the dimension of the first bent portion in the first direction is 1.5-3.0 mm.

[0009] The negative electrode connector includes a second main body and a second bent portion arranged at an angle, the second bent portion is provided with a second welding hole for the negative electrode column to pass through and connect, and a second annular welding portion is formed between the second welding hole and the negative electrode column; the second main body is electrically connected to the negative electrode tab; the size of the second main body in the second direction is 1.2~2.5mm, and the size of the second bent portion in the first direction is 1.2~2.5mm.

[0010] In the technical solution of the present application, the battery cells adopt the above-mentioned appropriate dimensions in the first and second directions, and the positive and negative electrode tabs are provided on both side ends in the second direction of the electrode assembly, that is, the tabs are provided on the opposite short sides, so as to reasonably and effectively improve the space utilization rate of the battery cells, thereby facilitating the acquisition of high energy density. The coordination of the above-mentioned dimensions of the first main body and the first bend of the positive electrode connector, the second main body and the second bend of the negative electrode connector is conducive to improving the overcurrent capacity, thereby improving the reliability of the stable passage of high current in the fast charging scenario. In addition, the first annular welding portion and the second annular welding portion formed in the technical solution of the present application are conducive to improving the stability and firmness of the welding, and are conducive to improving the reliability of the stable passage of high current.

[0011] In any embodiment, the sum of the dimensions of the first main portion in the first direction and the dimensions of the first bent portion in the second direction is 50 mm to 90 mm. This helps optimize the electron transmission path and thus reduces the internal resistance of the positive electrode connector.

[0012] In any embodiment, the sum of the size of the second main portion in the first direction and the size of the second bent portion in the second direction is 50 mm to 90 mm. This helps optimize the electron transmission path and thus reduces the internal resistance of the negative electrode connector.

[0013] In any embodiment, the size of the first main body in the first direction is 25% to 50% of the size of the battery cell in the first direction. This helps optimize the electron transmission path and thus reduces the internal resistance of the positive electrode connector.

[0014] In any embodiment, the size of the second main body in the first direction is 25% to 50% of the size of the battery cell in the first direction, thereby optimizing the electron transmission path and reducing the internal resistance of the negative electrode connector.

[0015] In any embodiment, the dimension of the first main body in the third direction is smaller than the dimension of the battery cell in the third direction, and the absolute value of the difference between the dimension of the first main body in the third direction and the dimension of the battery cell in the third direction is 5 mm to 15 mm. This facilitates effective contact between the positive electrode connector and the positive electrode tab.

[0016] In any embodiment, the dimension of the second main body in the third direction is smaller than the dimension of the battery cell in the third direction, and the absolute value of the difference between the dimension of the second main body in the third direction and the dimension of the battery cell in the third direction is 5 mm to 15 mm. This facilitates effective contact between the negative electrode connector and the positive electrode tab.

[0017] In any embodiment, each positive electrode tab is provided on at least one positive electrode tab, each positive electrode tab being provided at a first side end of the positive electrode tab in the second direction, and the size of the positive electrode tab in the first direction being 90% to 100% of the size of the positive electrode tab in the first direction. This helps to increase the contact area between the positive electrode tab and the positive electrode tab, thereby reducing the resistance when current passes through.

[0018] In any embodiment, each negative electrode tab is provided on at least one negative electrode tab, each negative electrode tab being provided at the second side end of the negative electrode tab in the second direction, and the dimension of the negative electrode tab in the first direction being 90% to 100% of the dimension of the negative electrode tab in the first direction. This helps to increase the contact area between the negative electrode tab and the positive electrode tab, thereby reducing the resistance when current passes through.

[0019] In any embodiment, the first bent portion includes a first welding section and a first connecting section. The first welding section is provided with a first welding hole. The first connecting section connects the first welding section and the first main portion. The first connecting section has a larger dimension in the first direction than the first welding section. The first welding section is relatively thin, which facilitates improved welding reliability. The first connecting section is relatively thick, which facilitates ensuring flow capacity.

[0020] In any embodiment, the dimension of the first connecting segment in the first direction is 1.5 to 3.0 mm, thereby improving the reliability of stable high current flow in fast charging scenarios.

[0021] In any embodiment, the dimension of the first welding section in the first direction is 1.0-2.5 mm, thereby facilitating both good welding stability and improved reliability of stable high current flow.

[0022] In any embodiment, on a side of the first bent portion facing away from the top cover, the first welding section is recessed relative to the first connecting section. The first welding section further includes an insulating sheet at least partially covering a surface of the first welding section, the insulating sheet being disposed between the first welding section and the electrode assembly. The provision of the insulating sheet prevents welding slag from falling into gaps between the electrode assemblies during welding of the positive electrode post to the positive connector.

[0023] In any embodiment, the second bent portion of the negative electrode connector includes a second welding segment and a second connecting segment. The second welding segment is provided with a second welding hole. The second connecting segment connects the second welding segment and the second main body. The second connecting segment has a larger dimension in the first direction than the second welding segment. The second welding segment is relatively thin, which facilitates improved welding reliability. The second connecting segment is relatively thick, which facilitates ensuring current flow capacity.

[0024] In any embodiment, the dimension of the second connecting segment in the first direction is 1.2 to 2.5 mm, thereby improving the reliability of high current stable passage in fast charging scenarios.

[0025] In any embodiment, the size of the second welding section in the first direction is 1.0-2.0 mm, thereby facilitating both good welding stability and improved reliability of stable high current flow.

[0026] In any embodiment, on a side of the second bent portion facing away from the top cover, the second welding section is recessed relative to the second connecting section. The second welding section further includes an insulating sheet at least partially covering a surface of the second welding section, the insulating sheet being disposed between the second welding section and the electrode assembly. The provision of the insulating sheet prevents welding slag from falling into the gap between the electrode assemblies when welding the negative electrode post to the negative electrode connector.

[0027] In any embodiment, the diameter of the positive electrode column is 9 to 22 mm, which is beneficial for improving the reliability of high current stable passage in fast charging scenarios.

[0028] In any embodiment, the diameter of the negative electrode column is 9 to 22 mm, which is beneficial for improving the reliability of high current stable passage in fast charging scenarios.

[0029] In any embodiment, the top cover includes a first edge and a second edge in the second direction, and the distance between the central axis of the positive electrode column and the first edge is 15-35 mm; the distance between the central axis of the negative electrode column and the second edge is 15-35 mm. The positioning of the positive and negative electrode columns facilitates a more rational battery structure and optimizes the electron transmission path.

[0030] In any embodiment, the positive electrode tab at least partially covers the first main body, thereby increasing the contact area between the positive electrode tab and the positive electrode connector and reducing internal resistance.

[0031] In any embodiment, the negative electrode tab at least partially covers the second main body, thereby increasing the contact area between the negative electrode tab and the negative electrode connector and reducing internal resistance.

[0032] In any embodiment, a thermal insulation film layer is provided between the negative electrode tab and the negative electrode connector, thereby facilitating heat isolation and improving battery reliability.

[0033] In any embodiment, a heat-insulating film layer is provided between the positive electrode tab and the positive electrode connector, thereby facilitating heat isolation and improving battery reliability.

[0034] In any embodiment, a heat-insulating film layer is provided between the electrode assembly and the housing, thereby facilitating heat isolation and improving battery reliability.

[0035] In any embodiment, a heat-insulating film layer is provided between the electrode assembly and the top cover, thereby facilitating heat isolation and improving battery reliability.

[0036] In any embodiment, the material of the thermal insulation film layer includes at least one of polyimide and polyethylene terephthalate. The thermal insulation film layer made of the above materials is beneficial for isolating heat and improving battery reliability.

[0037] In any embodiment, the thickness of the thermal insulation film layer is 10-100 μm. At this appropriate thickness, it is beneficial to reasonably utilize the battery space, isolate heat, and improve battery reliability.

[0038] In any embodiment, the dimension of the battery cell in the third direction is 30-50 mm. This suitable thickness is conducive to rationally utilizing the battery space and exerting the high energy density of the battery.

[0039] In any embodiment, the negative electrode plate includes a negative electrode current collector and a negative electrode film layer located on at least one side of the negative electrode current collector, the negative electrode film layer includes a first film layer and a second film layer, the first film layer is arranged on at least one surface of the negative electrode current collector, and the second film layer is arranged on the surface of the first film layer facing away from the current collector; wherein, the first film layer contains a first negative electrode active material; the second film layer contains a second negative electrode active material; the longest average particle size of the second negative electrode active material is smaller than the longest average particle size of the first negative electrode active material.

[0040] As a result, the longest average diameter of the active material used in the second membrane layer is relatively smaller, and the ion transmission distance in the second membrane layer is relatively shorter, which is conducive to further improving the fast charging performance of the battery cell. On the other hand, the longest average diameter of the active material used in the first membrane layer is relatively larger, and the compaction density of the first membrane layer is relatively higher, which is conducive to achieving good energy density.

[0041] In any embodiment, the longest average particle size of the first negative electrode active material is 7 to 18 μm, thereby facilitating the first film layer to have a relatively higher compaction density.

[0042] In any embodiment, the first negative electrode active material includes at least one of artificial graphite and natural graphite.

[0043] In any embodiment, the first negative electrode active material comprises a negative electrode active material in a secondary particle morphology.

[0044] In any embodiment, the volume distribution particle size Dv50 of the first negative electrode active material is 7 to 15 μm.

[0045] In any embodiment, the first negative electrode active material includes a carbon coating layer, wherein the thickness of the carbon coating layer is 100-500 nm. The carbon coating layer is beneficial for improving the conductivity of the negative electrode active material.

[0046] In any embodiment, the first negative electrode active material has a degree of graphitization of 90-94%.

[0047] In any embodiment, the first negative electrode active material includes a silicon material, wherein the silicon element in the silicon material accounts for 0.5-10% by weight of the first negative electrode active material. The addition of the silicon material is conducive to further improving the energy density of the battery cell.

[0048] In any embodiment, the longest average particle size of the second negative electrode active material is 6 to 10 μm, which is beneficial for the ion transmission distance in the second membrane layer to be relatively shorter.

[0049] In any embodiment, the second negative electrode active material includes at least one of artificial graphite and natural graphite.

[0050] In any embodiment, the second negative electrode active material comprises a negative electrode active material in a secondary particle morphology.

[0051] In any embodiment, the volume distribution particle size Dv50 of the second negative electrode active material is 7 to 15 μm.

[0052] In any embodiment, the second negative electrode active material includes a carbon coating layer, wherein the thickness of the carbon coating layer is 100-500 nm. The carbon coating layer is beneficial to improving the conductivity of the negative electrode active material.

[0053] In any embodiment, the second negative electrode active material has a degree of graphitization of 90-94%.

[0054] In any embodiment, the second negative electrode active material includes a silicon material, wherein the silicon element in the silicon material accounts for 0.5-10% by weight of the second negative electrode active material. The addition of the silicon material is conducive to further improving the energy density of the battery cell.

[0055] In any embodiment, the thickness of the first film layer is 30% to 70% of the total thickness of the negative electrode film layer, thereby facilitating the first film layer to play a role in taking into account the energy density of the battery cell.

[0056] In any embodiment, the thickness of the second film layer is 30% to 70% of the total thickness of the negative electrode film layer, thereby further improving the fast charging performance of the battery cell.

[0057] In any embodiment, when the state of charge (SOC) of the battery cell is 0%, the compaction density of the negative electrode film layer on a single side of the negative electrode sheet is 1.3-1.52 g / cc. Therefore, a suitable compaction density is conducive to further adjusting the porosity of the negative electrode sheet to an appropriate range.

[0058] In any embodiment, the surface density of the negative electrode film layer on a single side of the negative electrode sheet is 0.12-0.18 g / 1540.25 mm 2 Therefore, a suitable surface density is conducive to further adjusting the porosity of the negative electrode sheet to a suitable range.

[0059] In any embodiment, when the state of charge (SOC) of the battery cell is 0%, the compaction density of the positive electrode film layer on a single side of the positive electrode sheet is 2.3-2.6 g / cc. Therefore, a suitable compaction density is conducive to further adjusting the porosity of the positive electrode sheet to an appropriate range.

[0060] In any embodiment, the surface density of the positive electrode film layer on a single side of the positive electrode sheet is 0.25-0.33 g / 1540.25 mm 2 Therefore, a suitable surface density is conducive to further adjusting the porosity of the positive electrode sheet to a suitable range.

[0061] In any embodiment, the lithium-containing phosphate includes lithium iron phosphate, which includes a metal element, including at least one of aluminum, titanium, and vanadium. Adding the metal element to the lithium iron phosphate is beneficial for increasing the compaction density of the positive electrode active material.

[0062] In any embodiment, the metal element includes aluminum, and the weight percentage of aluminum in the lithium-containing phosphate is 0.02% to 0.25%. This is beneficial for aluminum doping to increase the compaction density of the positive electrode active material and further improve the cycle performance of the battery cell.

[0063] In any embodiment, the metal element includes titanium, and the mass proportion of titanium in the lithium-containing phosphate is 0.15% to 0.35%. This is beneficial for titanium doping to increase the compaction density of the positive electrode active material and further increase the battery capacity.

[0064] In any embodiment, the metal element includes vanadium, and the mass proportion of vanadium in the lithium-containing phosphate is 0.03% to 0.2%. This is beneficial for enhancing the compaction density of the positive electrode active material and further improving the charge and discharge performance of the battery cell.

[0065] In any embodiment, the lithium-containing phosphate includes lithium-containing phosphate in the form of primary particles and lithium-containing phosphate in the form of secondary particles. The mixed use of primary particles and secondary particles is beneficial to further adjust the compaction density of the positive electrode active material.

[0066] In any embodiment, the longest average particle size of the primary lithium phosphate particles is 300-800 nm, thereby shortening the ion transmission distance and improving the fast charging performance.

[0067] In any embodiment, the longest average particle size of the secondary lithium-containing phosphate particles is 8 μm to 15 μm. The secondary particles are usually composed of lithium-containing phosphate particles with smaller primary particles, which is beneficial for shortening the ion transmission distance.

[0068] In any embodiment, the secondary particle morphology of the lithium-containing phosphate is spherical or quasi-spherical.

[0069] In any embodiment, the volume distribution particle size Dv50 of the lithium-containing phosphate is 5 to 15 μm.

[0070] In a second aspect, the present application provides a battery device comprising the battery cell according to the first aspect of the present application.

[0071] In a third aspect, the present application provides an electrical device comprising the battery device of the second aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 A schematic structural diagram of a vehicle according to some embodiments of the present application;

[0073] Figure 2 Schematic diagram of the exploded structure of batteries according to some embodiments of the present application;

[0074] Figure 3 This is a schematic structural diagram of a battery cell in some embodiments of the present application;

[0075] Figure 4 This is a schematic diagram of the exploded structure of a battery cell according to some embodiments of the present application;

[0076] Figure 5 A front view of a positive electrode connector in a battery cell according to some embodiments of the present application;

[0077] Figure 6 A front view of a negative electrode connector in a battery cell according to some embodiments of the present application;

[0078] Figure 7 A top view of a positive electrode connector in a battery cell according to some embodiments of the present application;

[0079] Figure 8 A top view of a negative electrode connector in a battery cell according to some embodiments of the present application;

[0080] Figure 9 A front view of a positive electrode sheet and a positive electrode tab in a battery cell in some embodiments of the present application;

[0081] Figure 10 A front view of a negative electrode sheet and a negative electrode tab in a battery cell in some embodiments of the present application;

[0082] Figure 11 This is a front view of a top cover in a battery cell according to some embodiments of the present application.

[0083] Description of reference numerals:

[0084] 1000. Vehicle;

[0085] 100, battery, 200, controller, 300, motor;

[0086] 10. Box, 11. First part, 12. Second part;

[0087] 20. Battery cell, 21. Housing, 21a. Housing, 21b. Top cover, 21c. Positive electrode column, 21d. Negative electrode column, 22. Electrode assembly, 22a. Positive electrode sheet, 22b. Negative electrode sheet, 22c. Positive electrode tab, 22d. Negative electrode tab, 23. Positive electrode connector, 23a. First main body, 23b. First bend, 24. Negative electrode connector, 24a. Second main body, 24b. Second bend, 25. Insulating sheet,

[0088] 23b1, first welding section, 23b2, first connecting section, 23b3, first welding hole, 24b1, second welding section, 24b2, second connecting section, 24b3, second welding hole,

[0089] H1, the size of the battery cell in the first direction, W1, the size of the battery cell in the second direction, T1, the size of the battery cell in the third direction,

[0090] d1, the size of the first main body in the second direction, d2, the size of the first bending portion in the first direction, d3, the size of the second main body in the second direction, d4, the size of the second bending portion in the first direction, d5, the size of the first main body in the first direction, d6, the size of the first bending portion in the second direction, d7, the size of the second main body in the first direction, d8, the size of the second bending portion in the second direction, d9, the size of the first main body in the third direction, d10, the size of the second main body in the third direction, d11, the size of the positive electrode tab in the first direction, d12, the size of the negative electrode tab in the first direction, d13, the size of the first connecting section in the first direction, d14, the size of the first welding section in the first direction, d15, the size of the second connecting section in the first direction, d16, the size of the second welding section in the first direction, d17, the distance between the center axis of the positive electrode column and the first edge, d18, the distance between the center axis of the negative electrode column and the second edge. DETAILED DESCRIPTION

[0091] Below, the embodiments of the battery cells, battery devices, and electrical devices of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there may be cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0092] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0093] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0094] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0095] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0096] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0097] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0098] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0099] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0100] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0101] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", 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 the embodiments of the present 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 the embodiments of the present application.

[0102] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0103] The battery cells disclosed in the embodiments of the present application can be used in electrical devices that use batteries as power sources or various energy storage systems that use batteries as energy storage elements. Electrical devices can include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, battery-powered vehicles, electric vehicles, ships, spacecraft, and the like. Electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, among others.

[0104] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0105] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 may be provided 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 further 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, to meet the power requirements for starting, navigating and driving the vehicle 1000.

[0106] 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.

[0107] Please refer to Figure 2 , Figure 2An exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and battery cells 20, with the battery cells 20 housed within the housing 10. The housing 10 is used to provide a storage space for the battery cells 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for the battery cells 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 overlapping the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. The first portion 11 and the second portion 12 can also be hollow structures with one end open, with the open side of the first portion 11 overlapping 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, a rectangular parallelepiped, etc.

[0108] 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. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0109] Each battery cell 20 can be a secondary battery or a primary battery and can be cylindrical, flat, rectangular or other shapes.

[0110] The present application embodiment provides a battery cell 20, referring to Figure 3 and Figure 4 The dimension H1 of the battery cell in the first direction is 80-130 mm; the dimension W1 of the battery cell in the second direction is 200-350 mm; and the ratio of the dimension W1 of the battery cell in the second direction to the dimension H1 of the battery cell in the first direction is 1.5-4.4.

[0111] The battery cell 20 includes a housing 21, an electrode assembly 22, a positive electrode connector 23, and a negative electrode connector 24. The housing 21 includes a shell 21a and a top cover 21b covering an end of the shell 21a in a first direction. A positive electrode column 21c and a negative electrode column 21d are provided on the top cover 21b along a second direction. The electrode assembly 22 is disposed in the housing 21.

[0112] The electrode assembly 22 includes a plurality of positive electrode sheets 22a and a plurality of negative electrode sheets 22b stacked in the third direction, and a positive electrode tab 22c and a negative electrode tab 22d located at both ends of the electrode assembly 22 in the second direction. The positive electrode active material of the positive electrode sheet 22a includes a lithium-containing phosphate, and the negative electrode active material of the negative electrode sheet 22b includes graphite.

[0113] See also Figure 4-Figure 5 、 Figure 7 The positive electrode connector 23 includes a first main body portion 23a and a first bent portion 23b arranged at an angle. The first bent portion 23b is provided with a first welding hole 23b3 for the positive electrode column 21c to pass through and connect, and a first annular welding portion is formed between the first welding hole 23b3 and the positive electrode column 21c. The first main body portion 23a is electrically connected to the positive electrode tab 22c; the dimension d1 of the first main body portion in the second direction is 1.5-3.0 mm, and the dimension d2 of the first bent portion in the first direction is 1.5-3.0 mm;

[0114] See also Figure 4 、 Figure 6 and Figure 8 The negative electrode connector 24 includes a second main body portion 24a and a second bent portion 24b arranged at an angle. The second bent portion 24b is provided with a second welding hole 24b3 for the negative electrode post 21d to pass through and connect, and a second annular welding portion is formed between the second welding hole 24b3 and the negative electrode post 21d; the second main body portion 24a is electrically connected to the negative electrode tab 22d; the dimension d3 of the second main body portion in the second direction is 1.2~2.5mm, and the dimension d4 of the second bent portion in the first direction is 1.2~2.5mm.

[0115] This application embodiment defines three reference directions. Figure 3 As shown in , the first direction in the figure is the height direction of the battery cell, the second direction is the width direction of the battery cell, and the third direction is the thickness direction of the battery cell.

[0116] In the embodiment of the present application, each positive electrode sheet 22a is provided with at least one positive electrode tab 22c, and each negative electrode sheet 22b is provided with at least one negative electrode tab 22d. Multiple positive electrode sheets 22a and multiple negative electrode sheets 22b are stacked so that each positive electrode tab 22c is located at the first side end in the second direction of the electrode assembly 22, and each negative electrode tab 22d is located at the second side end in the second direction of the electrode assembly 22, that is, the positive electrode tab and the negative electrode tab are respectively located at the two side ends in the second direction of the electrode assembly 22.

[0117] In the embodiment of the present application, the dimension d1 of the first main body in the second direction can be understood as the thickness of the first main body 23a, and the dimension d2 of the first bend in the first direction can be understood as the thickness of the first bend 23b. They are positively correlated with the size of the current flow cross section.

[0118] In the embodiment of the present application, the first main portion 23a and the first bent portion 23b "arranged at an angle" may refer to the angle formed so that the first main portion 23a and the first bent portion 23b conform to the edge shape of the electrode assembly 22. Similarly, the second main portion 24a and the second bent portion 24b "arranged at an angle" may refer to the angle formed so that the second main portion 24a and the second bent portion 24b conform to the edge shape of the electrode assembly 22. The angle may be an acute angle, a right angle, or an obtuse angle.

[0119] In the embodiment of the present application, the dimension d2 of the first bending portion in the first direction may refer to the maximum dimension of the first bending portion in the first direction, and the dimension d4 of the second bending portion in the first direction may refer to the maximum dimension of the second bending portion in the first direction.

[0120] Illustratively, the first annular weld portion formed between the first welding hole 23b3 and the positive electrode column 21c, and the second annular weld portion formed between the second welding hole 24b3 and the negative electrode column 21d, can be formed by butt welding.

[0121] In an embodiment of the present application, the shape of the top cover 21b can be adapted to the shape of the housing 21a to match the housing 21a. Optionally, the top cover 21b can be made of a material with a certain hardness and strength (such as an aluminum alloy). In this way, the top cover 21b is less likely to deform when subjected to compression or collision, allowing the battery cell 20 to have a higher structural strength. The positive and negative electrode columns are electrically connected to the electrode assembly 22 via the positive connector 23 and the negative connector 24, respectively, for outputting or inputting electrical energy into or out of the battery cell 20. In some embodiments, the top cover 21b may 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. The housing 21a is a component used to cooperate with the top cover 21b to form an internal environment for the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 22, electrolyte, and other components.

[0122] The electrode assembly 22 is the component in the battery cell where the electrochemical reaction occurs. One or more electrode assemblies 22 may be contained within the housing 21a. The positive electrode tab 22c and the negative electrode tab 22d are each composed of the portion of the positive electrode sheet 22a and the portion of the negative electrode sheet 22b that does not contain active material. A separator is usually provided between the positive electrode sheet 22a and the negative electrode sheet 22b. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, the positive electrode sheet 22a is connected to the positive electrode column 21c via the positive electrode connector 23, and the negative electrode sheet 22b is connected to the negative electrode column 21d via the negative electrode connector 24 to form a current circuit.

[0123] It can be understood that in the embodiment of the present application, the size of the electrode assembly 22 is close to the size of the battery cell 20, and there is a gap between the electrode assembly 22 and the inner wall of the battery cell 20. The gap only needs to allow the electrode assembly 22 to be placed in and taken out along the inner wall of the battery cell 20.

[0124] The dimension H1 (i.e., height) of the battery cell in the first direction may be 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, or a numerical range consisting of any two of the above numerical ranges. The dimension W1 (i.e., width) of the battery cell in the second direction may be 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, 260mm, 270mm, 280mm, 290mm, 300mm, 310mm, 320mm, 330mm, 340mm, 350mm, or a numerical range consisting of any two of the above numerical ranges. The ratio of the size W1 of the battery cell in the second direction to the size H1 of the battery cell in the first direction can be 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4 or a numerical range consisting of any two of the above numerical ranges.

[0125] The dimension d1 (i.e., thickness) of the first main portion in the second direction may be 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3.0 mm, or a numerical range consisting of any two of the above numerical ranges. The dimension d2 (i.e., thickness) of the first bent portion in the first direction may be 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3.0 mm, or a numerical range consisting of any two of the above numerical ranges.

[0126] The dimension d3 (i.e., thickness) of the second main portion in the second direction may be 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, or a numerical range consisting of any two of the above numerical ranges. The dimension d4 (i.e., thickness) of the second bent portion in the first direction may be 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, or a numerical range consisting of any two of the above numerical ranges.

[0127] In the technical solution of the present application, the battery cell 20 adopts the above-mentioned appropriate dimensions in the first and second directions, and is provided with a positive electrode tab 22c and a negative electrode tab 22d at both ends in the second direction of the electrode assembly 22, that is, tabs on the opposite short sides, so as to reasonably and effectively improve the space utilization rate of the battery cell, thereby facilitating the acquisition of a high energy density. The coordination of the above-mentioned dimensions of the first main body 23a, the first bent portion 23b, the second main body 24a, and the second bent portion 24b of the positive electrode connector 23 is conducive to improving the overcurrent capacity, thereby improving the reliability of the stable passage of high current in the fast charging scenario. In addition, the first annular weld portion and the second annular weld portion formed in the technical solution of the present application are conducive to improving the stability and firmness of the welding, and are conducive to improving the reliability of the stable passage of high current.

[0128] In some embodiments, see Figure 5The sum of the dimension d5 of the first main body in the first direction and the dimension d6 of the first bent portion in the second direction is 50 mm to 90 mm. The sum of the dimension d5 of the first main body in the first direction and the dimension d6 of the first bent portion in the second direction can be 50 mm, 51 mm, 52 mm, 53 mm, 54 mm, 55 mm, 56 mm, 57 mm, 58 mm, 59 mm, 60 mm, 61 mm, 62 mm, 63 mm, 64 mm, 65 mm, 66 mm, 67 mm, 68 mm, 69 mm, 70 mm, 71 mm, 72 mm, 73 mm, 74 mm, 75 mm, 76 mm, 77 mm, 78 mm, 79 mm, 80 mm, 81 mm, 82 mm, 83 mm, 84 mm, 85 mm, 86 mm, 87 mm, 88 mm, 89 mm, 90 mm, or a numerical range consisting of any two of the above numerical ranges. This helps optimize the electron transmission path, thereby reducing the internal resistance of the positive electrode connector 23.

[0129] In some embodiments, see Figure 6 The sum of the dimension d7 of the second main body in the first direction and the dimension d8 of the second bent portion in the second direction is 50 mm to 90 mm. The sum of the dimension d7 of the second main body in the first direction and the dimension d8 of the second bent portion in the second direction can be 50 mm, 51 mm, 52 mm, 53 mm, 54 mm, 55 mm, 56 mm, 57 mm, 58 mm, 59 mm, 60 mm, 61 mm, 62 mm, 63 mm, 64 mm, 65 mm, 66 mm, 67 mm, 68 mm, 69 mm, 70 mm, 71 mm, 72 mm, 73 mm, 74 mm, 75 mm, 76 mm, 77 mm, 78 mm, 79 mm, 80 mm, 81 mm, 82 mm, 83 mm, 84 mm, 85 mm, 86 mm, 87 mm, 88 mm, 89 mm, 90 mm, or a numerical range consisting of any two of the above numerical ranges. This helps optimize the electron transmission path, thereby reducing the internal resistance of the negative electrode connector 24.

[0130] In some embodiments, the dimension d5 of the first main portion in the first direction is 25% to 50% of the dimension H1 of the battery cell in the first direction. This helps optimize the electron transmission path and thus reduces the internal resistance of the positive electrode connector 23. The dimension d5 of the first main portion in the first direction can be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50% of the dimension of the electrode assembly 22 in the first direction, or a numerical range consisting of any two of the above numerical ranges.

[0131] In some embodiments, dimension d7 of the second main portion in the first direction is 25% to 50% of dimension H1 of the battery cell in the first direction. This helps optimize the electron transmission path and thus reduces the internal resistance of the negative electrode connector 24. Dimension d7 of the second main portion in the first direction can be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or any two of the above ranges of dimension H1 of the battery cell in the first direction.

[0132] In some embodiments, see Figure 7 , the dimension d9 of the first main body in the third direction is smaller than the dimension T1 of the battery cell in the third direction, and the absolute value of the difference between the dimension d9 of the first main body in the third direction and the dimension T1 of the battery cell in the third direction is 5mm~15mm. As an example, in an embodiment of the present application, the dimension d9 of the first main body in the third direction is the same as the dimension of the first bent portion in the third direction. This is conducive to the effective contact between the positive electrode connector 23 and the positive electrode tab. The absolute value of the above difference can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm or a numerical interval consisting of any two of the above numerical ranges.

[0133] In some embodiments, see Figure 8 , the dimension d10 of the second main body in the third direction is smaller than the dimension T1 of the battery cell in the third direction, and the absolute value of the difference between the dimension d10 of the second main body in the third direction and the dimension T1 of the battery cell in the third direction is 5mm~15mm. As an example, in an embodiment of the present application, the dimension d9 of the first main body in the third direction is the same as the dimension of the first bent portion in the third direction. This is conducive to effective contact between the negative electrode connector 24 and the positive electrode tab. The absolute value of the above difference can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, or a numerical interval consisting of any two of the above numerical ranges.

[0134] In some embodiments, see Figure 9Each positive electrode tab 22a is provided with at least one positive electrode tab 22c. Each positive electrode tab 22c is provided at a first side end of the positive electrode tab 22a in the second direction. The dimension d11 of the positive electrode tab in the first direction is 90% to 100% of the dimension of the positive electrode tab 22a in the first direction. This helps increase the contact area between the positive electrode tab and the positive electrode tab 22a, thereby reducing the resistance when current passes through. The dimension d11 of the positive electrode tab in the first direction can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100% of the dimension of the positive electrode tab 22a in the first direction, or a numerical range consisting of any two of the above numerical ranges.

[0135] In the embodiment of the present application, as an example, the shape of the positive electrode tab 22c can be square. In this case, the dimension d11 of the positive electrode tab in the first direction is the same. It is understood that the shape of the positive electrode tab 22c can also be other existing feasible shapes, such as a trapezoid or other irregular shapes. In this case, the dimension d11 of the positive electrode tab in the first direction can refer to the dimension at the connection between the positive electrode sheet 22a and the positive electrode tab 22c.

[0136] In some embodiments, see Figure 10 Each negative electrode tab 22b is provided with at least one negative electrode tab 22d. Each negative electrode tab 22d is located at the second side end of the negative electrode tab 22b in the second direction. The dimension d12 of the negative electrode tab in the first direction is 90% to 100% of the dimension of the negative electrode tab 22b in the first direction. This helps increase the contact area between the negative electrode tab 22d and the positive electrode tab 22a, thereby reducing the resistance when current flows. The dimension d12 of the negative electrode tab in the first direction can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, or any two of the above values ​​of the dimension of the negative electrode tab 22b in the first direction.

[0137] In the embodiment of the present application, as an example, the shape of the negative electrode tab 22d can be square. In this case, the dimension d12 of the negative electrode tab in the first direction is the same. It is understood that the shape of the negative electrode tab 22d can also be other existing feasible shapes, such as a trapezoid or other irregular shapes. In this case, the dimension d12 of the negative electrode tab in the first direction can refer to the dimension at the connection between the negative electrode tab 22b and the negative electrode tab 22d.

[0138] In some embodiments, see Figure 5The first bent portion 23b includes a first welding section 23b1 and a first connecting section 23b2. The first welding section 23b1 is provided with a first welding hole 23b3. The first connecting section 23b2 connects the first welding section 23b1 to the first main portion 23a. The dimension d13 of the first connecting section in the first direction is greater than the dimension d14 of the first welding section in the first direction. The first bent portion is stepped. The first welding section 23b1 is relatively thin, which improves welding reliability. The first connecting section 23b2 is relatively thick, which helps ensure current flow capacity.

[0139] In some embodiments, the dimension d13 of the first connecting segment in the first direction is 1.5-3.0 mm. This is beneficial to improving the reliability of stable high current flow in fast charging scenarios. The dimension d15 of the second connecting segment in the first direction can be 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3.0 mm, or a numerical range consisting of any two of the above numerical ranges.

[0140] In some embodiments, the dimension d14 of the first welding section in the first direction is 1.0-2.5 mm. This helps ensure both good welding stability and improved reliability of high current flow. The dimension d14 of the first welding section in the first direction can be 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, or a range consisting of any two of the above ranges.

[0141] In some embodiments, see Figure 4 and Figure 5 On the side of the first bend 23b facing away from the top cover 21b, the first welding section 23b1 is recessed relative to the first connecting section 23b2. The first welding section 23b1 also includes an insulating sheet 25 that at least partially covers the surface of the first welding section 23b1 and is positioned between the first welding section 23b1 and the electrode assembly 22. It will be appreciated that the recessed portion located on the side facing away from the top cover 21b allows the insulating sheet 25 to be positioned between the first welding section 23b1 and the electrode assembly 22. The provision of the insulating sheet 25 prevents welding slag from entering the gap between the electrode assemblies 22 during welding of the positive electrode column 21c and the positive connector 23.

[0142] In some embodiments, see Figure 6The second bent portion 24b of the negative electrode connector 24 includes a second welding segment 24b1 and a second connecting segment 24b2. A second welding hole 24b3 is defined in the second welding segment 24b1. The second connecting segment 24b2 connects the second welding segment 24b1 with the second main body 24a. Dimension d15 of the second connecting segment in the first direction is greater than dimension d16 of the second welding segment in the first direction. Similarly, the second bent portion is stepped. The second welding segment 24b1 is relatively thin, which improves welding reliability, while the second connecting segment 24b2 is relatively thick, which helps ensure current flow capacity.

[0143] In some embodiments, the dimension d15 of the second connecting segment in the first direction is 1.2-2.5 mm. This helps improve the reliability of stable high current flow in fast charging scenarios. The dimension d15 of the second connecting segment in the first direction can be 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, or a numerical range consisting of any two of the above numerical ranges.

[0144] In some embodiments, the dimension d16 of the second welding section in the first direction is 1.0-2.0 mm. This helps ensure both good welding stability and improved reliability of high current flow. The dimension d16 of the second welding section in the first direction can be 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, or a range consisting of any two of the above ranges.

[0145] In some embodiments, see Figure 4 and Figure 6 On the side of the second bend facing away from the top cover 21b, the second welding section 24b1 is recessed relative to the second connecting section 24b2. The second welding section 24b1 also includes an insulating sheet 25 that at least partially covers the surface of the second welding section 24b1 and is positioned between the second welding section 24b1 and the electrode assembly 22. It will be appreciated that the recessed portion located on the side facing away from the top cover 21b allows the insulating sheet 25 to be positioned between the second welding section 24b1 and the electrode assembly 22. The provision of the insulating sheet 25 prevents welding slag from entering the gap between the electrode assemblies 22 during welding of the negative electrode column 21d and the negative connector 24.

[0146] In some embodiments, the diameter of the positive electrode column 21c is 9-22 mm. This helps improve the reliability of high current stability in fast charging scenarios. The diameter of the positive electrode column 21c can be 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, or a numerical range consisting of any two of the above numerical ranges.

[0147] In some embodiments, the diameter of the negative electrode column 21d is 9-22 mm. This helps improve the reliability of high current stability in fast charging scenarios. The diameter of the negative electrode column 21d can be 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, or a range consisting of any two of the above ranges.

[0148] In some embodiments, see Figure 11 , the top cover 21b includes a first edge and a second edge in the second direction, and the distance d17 between the central axis of the positive electrode column and the first edge is 15-35mm; the distance d18 between the central axis of the negative electrode column and the second edge is 15-35mm. The position setting of the positive electrode column 21c and the negative electrode column 21d is conducive to making the battery structure more reasonable and optimizing the electron transmission path. The distance d17 between the central axis of the positive electrode column and the first edge can be 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm or a numerical interval consisting of any two of the above numerical ranges. The distance d18 between the central axis of the negative electrode and the second edge can be 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm or a numerical interval consisting of any two of the above numerical ranges.

[0149] In some embodiments, the positive electrode tab 22c at least partially covers the first main body. Due to the presence of multiple layers of positive electrode tabs, the positive electrode tab 22c can be bent and partially or completely covered on the first main body 23a. This helps increase the contact area between the positive electrode tab 22c and the positive electrode connector 23, reducing internal resistance. In some embodiments, the negative electrode tab 22d at least partially covers the second main body. Similarly, due to the presence of multiple layers of negative electrode tabs 22d, the negative electrode tab 22d can be bent and partially or completely covered on the second main body 24a. This helps increase the contact area between the negative electrode tab 22d and the negative electrode connector 24, reducing internal resistance.

[0150] In some embodiments, a thermal insulation film layer is provided between the negative electrode tab 22d and the negative electrode connector 24, thereby facilitating heat isolation and improving battery reliability.

[0151] In some embodiments, a heat-insulating film layer is provided between the positive electrode tab 22c and the positive electrode connector 23. This helps to isolate heat and improve battery reliability.

[0152] In some embodiments, a heat-insulating film layer is provided between the electrode assembly 22 and the housing 21a, thereby isolating heat and improving battery reliability.

[0153] In some embodiments, a heat-insulating film layer is disposed between the electrode assembly 22 and the top cover 21b, thereby isolating heat and improving battery reliability.

[0154] In some embodiments, the thermal insulation film layer is made of at least one of polyimide and polyethylene terephthalate. The thermal insulation film layer made of the above materials is beneficial for isolating heat and improving battery reliability.

[0155] In some embodiments, the thickness of the thermal insulation film layer is 10-100 μm. This suitable thickness facilitates the rational use of battery space, helps isolate heat, and improves battery reliability. The thickness of the thermal insulation film layer can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or a range consisting of any two of the above ranges.

[0156] In some embodiments, the dimension T1 of the battery cell in the third direction is 30-50 mm. This suitable thickness facilitates efficient use of battery space and maximizes the battery's high energy density. The dimension T1 of the battery cell in the third direction can be 30 mm, 32 mm, 34 mm, 35 mm, 36 mm, 38 mm, 40 mm, 42 mm, 44 mm, 45 mm, 46 mm, 48 mm, 50 mm, or any two of the above ranges.

[0157] In some embodiments, the negative electrode plate 22b includes a negative electrode current collector and a negative electrode film layer located on at least one side of the negative electrode current collector, the negative electrode film layer includes a first film layer and a second film layer, the first film layer is arranged on at least one surface of the negative electrode current collector, and the second film layer is arranged on the surface of the first film layer facing away from the current collector; wherein, the first film layer contains a first negative electrode active material; the second film layer contains a second negative electrode active material; the longest average particle size of the second negative electrode active material is smaller than the longest average particle size of the first negative electrode active material.

[0158] In this article, "the longest diameter average particle size" refers to the process of ion polishing and cutting the electrode along the thickness direction to expose the cross-section of the film layer. The cross-section of the film layer can be tested by scanning electron microscopy (SEM). At a magnification of 1000 times in the SEM scene, more than 50 particles are randomly selected and the length of the longest straight line passing through the center point of a single particle and extending to the periphery of the particle is measured. The average length of the longest straight lines of these particles is then taken.

[0159] As a result, the longest average diameter of the active material used in the second membrane layer is relatively smaller, and the ion transmission distance in the second membrane layer is relatively shorter, which is conducive to further improving the fast charging performance of the battery cell. On the other hand, the longest average diameter of the active material used in the first membrane layer is relatively larger, and the compaction density of the first membrane layer is relatively higher, which is conducive to achieving good energy density.

[0160] In some embodiments, the longest average particle size of the first negative electrode active material is 7 to 18 μm. This facilitates the first film layer to have a relatively higher compaction density. The longest average particle size of the first negative electrode active material can be 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, or a range consisting of any two of the above values.

[0161] In some embodiments, the first negative electrode active material includes at least one of artificial graphite and natural graphite.

[0162] In some embodiments, the first negative electrode active material comprises a negative electrode active material in a secondary particle morphology.

[0163] In this application, particles with primary particle morphology refer to primary particles. Primary particles are the smallest unit of particles within a certain observation range. Primary particles may contain any form of defects, but it is impossible to define smaller particles within a primary particle. Primary particles may aggregate under physical forces such as van der Waals forces, but this aggregation is easily disaggregated by external forces such as ultrasound, stirring, and roller compaction, ensuring that the main component form of the active material in the membrane layer remains primary particles.

[0164] In this application, particles with secondary particle morphology refer to secondary particles. Secondary particles are formed by the agglomeration of primary particles and are not easily dispersed under external forces such as ultrasound. However, after cutting the cross section of the secondary particles, it can be seen that the secondary particles are formed by the agglomeration of many primary particles.

[0165] In some embodiments, the volume distribution particle size Dv50 of the first negative electrode active material is 7 to 15 μm. The volume distribution particle size Dv50 of the first negative electrode active material can be 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or a numerical range consisting of any two of the above values.

[0166] In this application, the volume distribution particle size Dv50 of a material represents the particle size corresponding to the cumulative volume distribution percentage of the material reaching 50%, and can be measured using instruments and methods known in the art. For example, it can be conveniently measured using a laser particle size analyzer, referring to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method. The testing instrument can be a Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK.

[0167] In some embodiments, the first negative electrode active material includes a carbon coating layer having a thickness of 100 to 500 nm. The carbon coating layer helps improve the conductivity of the negative electrode active material. The thickness of the carbon coating layer can be 100 nm, 150 nm, 200 nm, 350 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, or a range consisting of any two of the above values.

[0168] The thickness of the coating can be characterized using transmission electron microscopy (TEM). By observing the negative electrode active material using TEM, the coating layer covering the surface of the negative electrode active material can be clearly observed based on the differences in the lattice fringes. Five locations within the coating layer are randomly selected for testing, and the average value is calculated as the average thickness of the coating layer.

[0169] In some embodiments, the first negative electrode active material has a degree of graphitization of 90-94%. A high degree of graphitization indicates a smaller inter-layer spacing, smaller lattice rotation, less scattered stacking of layers, and more orderly arrangement. This results in a higher specific capacity and facilitates the production of high-energy-density battery cells. The degree of graphitization of the first negative electrode active material can be 90%, 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94%, or a range consisting of any two of these values.

[0170] In this article, the term "degree of graphitization" macroscopically characterizes the proportion of the material that reaches a complete graphite crystal structure; microscopically, it refers to the degree to which the carbon structure in different transition states approaches the ideal graphite crystal.

[0171] In this application, the degree of graphitization of graphite can be tested using instruments and methods known in the art. For example, an X-ray diffractometer (such as a Bruker D8 Discover) can be used for testing. The test can refer to JISK 0131-1996 and JB / T 4220-2011. The average interlayer spacing d002 of the C(002) plane in the material's crystal structure is obtained. The degree of graphitization is then calculated using the formula g = (0.344 - d002) / (0.344 - 0.3354) × 100%. In the above formula, d002 is the average interlayer spacing of the C(002) plane in the material's crystal structure, expressed in nanometers (nm).

[0172] In some embodiments, the first negative electrode active material includes a silicon material, and the mass proportion of silicon in the silicon material in the first negative electrode active material is 0.5% to 10%. The addition of silicon material helps further improve the energy density of the battery cell. The mass proportion of silicon in the silicon material in the first negative electrode active material can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or a numerical range consisting of any two of the above values.

[0173] In the present application, the silicon content can be measured using instruments and methods known in the art. For example, the negative electrode active material can be placed in an appropriate amount of concentrated nitric acid as a digestion solvent and digested using a plate digestion method. Finally, the solvent can be dissolved and extracted using hydrochloric acid. The resulting solution is then diluted to an appropriate volume and quantitatively measured using an inductively coupled plasma optical emission spectrometer (ICP=OES).

[0174] In some embodiments, the second negative electrode active material has an average particle size of 6 to 10 μm in its longest diameter. This facilitates the effect of a relatively shorter ion transport distance in the second membrane layer. The average particle size of the second negative electrode active material can be 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or a range consisting of any two of these values.

[0175] In some embodiments, the second negative electrode active material includes at least one of artificial graphite and natural graphite.

[0176] In some embodiments, the second negative electrode active material comprises a negative electrode active material in a secondary particle morphology.

[0177] In some embodiments, the volume distribution particle size Dv50 of the second negative electrode active material is 7 to 15 μm. The volume distribution particle size Dv50 of the second negative electrode active material can be 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or a numerical range consisting of any two of the above values.

[0178] In some embodiments, the second negative electrode active material includes a carbon coating layer having a thickness of 100 to 500 nm. The carbon coating layer helps improve the conductivity of the negative electrode active material. The thickness of the carbon coating layer can be 100 nm, 150 nm, 200 nm, 350 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, or a range consisting of any two of the above values.

[0179] In some embodiments, the second negative electrode active material has a degree of graphitization of 90-94%. A high degree of graphitization indicates a smaller inter-layer spacing, smaller lattice rotation, less scattered stacking of layers, and more orderly arrangement. This results in a higher specific capacity and facilitates the production of high-energy-density battery cells. The degree of graphitization of the second negative electrode active material can be 90%, 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94%, or any two of these values.

[0180] In some embodiments, the second negative electrode active material includes a silicon material, wherein the mass fraction of silicon in the silicon material is 0.5-10%. The addition of the silicon material helps further improve the energy density of the battery cell. The mass fraction of silicon in the silicon material can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or a numerical range consisting of any two of the above values.

[0181] In some embodiments, the thickness of the first film layer is 30% to 70% of the total thickness of the negative electrode film layer. This facilitates the first film layer's role in balancing the energy density of the battery cell. The thickness of the first film layer can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% of the total thickness of the negative electrode film layer, or a range consisting of any two of these values.

[0182] In some embodiments, the thickness of the second film layer is 30% to 70% of the total thickness of the negative electrode film layer. This helps further improve the fast charging performance of the battery cell. The thickness of the second film layer can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% of the total thickness of the negative electrode film layer, or a range consisting of any two of these values.

[0183] The thickness of the first film layer and the thickness of the second film layer can be characterized by transmission electron microscopy (TEM). A cross-section of the negative electrode sheet is observed using TEM. The thickness of the first and second film layers is determined based on the difference in the longest average particle size of the active material in the first and second film layers. For example, the thickness of the first and second film layers is averaged after five observations.

[0184] In some embodiments, when the state of charge (SOC) of the battery cell is 0%, the compaction density of the negative electrode film layer on a single side of the negative electrode sheet is 1.3-1.52 g / cc. Therefore, a suitable compaction density is conducive to further adjusting the porosity of the negative electrode sheet to an appropriate range. Under the condition that the state of charge (SOC) of the battery cell is 0%, the compaction density of the negative electrode film layer on a single side of the negative electrode sheet may be 1.3g / cc, 1.31g / cc, 1.32g / cc, 1.33g / cc, 1.34g / cc, 1.35g / cc, 1.36g / cc, 1.37g / cc, 1.38g / cc, 1.39g / cc, 1.4g / cc, 1.41g / cc, 1.42g / cc, 1.43g / cc, 1.44g / cc, 1.45g / cc, 1.46g / cc, 1.47g / cc, 1.48g / cc, 1.49g / cc, 1.5g / cc, 1.51g / cc, 1.52g / cc or a numerical range consisting of any two of the above values.

[0185] In this application, the compaction density of the pole piece has a meaning well known in the art and can be tested using methods known in the art. When the state of charge (SOC) of the battery cell is 0%, the pole piece is removed from the lithium-ion battery, and a certain area of ​​the pole piece is taken. The mass and thickness of the pole piece and the current collector after the film layer is removed are measured respectively. The compaction density of the pole piece is calculated according to the following formula: Pole piece compaction density = (pole piece mass - current collector mass) / [(pole piece thickness - current collector thickness) × pole piece area].

[0186] In some embodiments, the surface density of the negative electrode film layer on a single side of the negative electrode sheet is 0.12-0.18 g / 1540.25 mm 2 Therefore, the appropriate surface density is conducive to further adjusting the porosity of the negative electrode sheet to an appropriate range. The surface density of the negative electrode film layer on a single side of the negative electrode sheet can be 0.12g / 1540.25mm 2 、0.13g / 1540.25mm 2 、0.14g / 1540.25mm 2 、0.15g / 1540.25mm 2 、0.16g / 1540.25mm 2 、0.17g / 1540.25mm 2 、0.18g / 1540.25mm 2 Or a numerical range consisting of any two of the above values.

[0187] In this application, the surface density of the film layer has a meaning well known in the art and can be tested using methods known in the art. For example, take a pole piece that is coated on one side and cold pressed (if it is a pole piece coated on both sides, the film layer on one side can be wiped off), punch it into small discs with an area of ​​S1, weigh it, and record it as M1. Then wipe off the film layer of the pole piece after the above weighing, weigh the weight of the current collector, and record it as M0. The single-side density of the film layer = (M1 - M0) / S1. In order to ensure the accuracy of the test results, multiple groups (for example, 10 groups) of test samples can be tested, and the average value can be calculated as the test result.

[0188] In some embodiments, under the condition that the state of charge SOC of the battery cell is 0%, the compaction density of the single-sided positive electrode film layer of the positive electrode sheet is 2.3~2.6g / cc. Thus, the appropriate compaction density is conducive to further adjusting the porosity of the positive electrode sheet within a suitable range. Under the condition that the state of charge SOC of the battery cell is 0%, the compaction density of the single-sided positive electrode film layer of the positive electrode sheet can be 2.3g / cc, 2.31g / cc, 2.32g / cc, 2.33g / cc, 2.34g / cc, 2.35g / cc, 2.36g / cc, 2.37g / cc, 2.38g / cc, 2.39g / cc, 2.4g / cc, 2.41g / cc, 2.42g / cc, 2.43g / cc, 2.44g / cc, 2.45g / cc, 2.46g / cc, 2.47g / cc, 2.48g / cc, 2.49g / cc, 2.5g / cc, 2.51g / cc, 2.52g / cc, 2.53g / cc, 2.54g / cc, 2.55g / cc, 2.56g / cc, 2.57g / cc, 2.58g / cc, 2.59g / cc, 2.6g / cc or a numerical range consisting of any two of the above values.

[0189] In some embodiments, the surface density of the single-sided positive electrode film layer of the positive electrode sheet is 0.25~0.33g / 1540.25mm 2 Therefore, the appropriate surface density is conducive to further adjusting the porosity of the positive electrode sheet to an appropriate range. The surface density of the single-sided positive electrode film layer of the positive electrode sheet can be 0.25g / 1540.25mm 2 、0.26g / 1540.25mm 2 , 0.27g / 1540.25mm 2 、0.28g / 1540.25mm 2 , 0.29g / 1540.25mm 2 、0.3g / 1540.25mm 2 、0.31g / 1540.25mm 2 、0.32g / 1540.25mm 2 、0.33g / 1540.25mm 2 Or a numerical range consisting of any two of the above values.

[0190] In some embodiments, the lithium-containing phosphate includes lithium iron phosphate, which includes a metal element, including at least one of aluminum, titanium, and vanadium. Adding the metal element to the lithium iron phosphate helps increase the compaction density of the positive electrode active material.

[0191] In the present application, the aluminum, titanium, and vanadium contents in lithium-containing phosphates can be tested using instruments and methods known in the art. For example, the lithium-containing phosphate can be placed in an appropriate amount of concentrated nitric acid as a digestion solvent and digested using a plate digestion method. Finally, the extraction solvent can be dissolved with hydrochloric acid. The resulting solution can then be diluted to an appropriate volume and quantitatively tested using an inductively coupled plasma optical emission spectrometer (ICP-OES).

[0192] In some embodiments, the metal element includes aluminum, and the weight percentage of aluminum in the lithium-containing phosphate is 0.02% to 0.25%. This is beneficial for aluminum doping to increase the compaction density of the positive electrode active material and further improve the cycle performance of the battery cell. The weight percentage of aluminum in the lithium-containing phosphate can be 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, or a numerical range consisting of any two of the above values.

[0193] In some embodiments, the metal element includes titanium, and the mass proportion of the titanium in the lithium-containing phosphate is 0.15% to 0.35%. As a result, it is beneficial to play the role of titanium doping in increasing the compaction density of the positive electrode active material and further increasing the battery capacity. The mass proportion of titanium in the lithium-containing phosphate can be 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, or a numerical range consisting of any two of the above values.

[0194] In some embodiments, the metal element includes vanadium, and the mass proportion of the vanadium in the lithium-containing phosphate is 0.03% to 0.2%. This is beneficial for vanadium doping to increase the compaction density of the positive electrode active material and further improve the charge and discharge performance of the battery cell. The mass proportion of vanadium in the lithium-containing phosphate can be 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, or a numerical range consisting of any two of the above values.

[0195] In some embodiments, the lithium-containing phosphate includes a primary particle-shaped lithium-containing phosphate and a secondary particle-shaped lithium-containing phosphate. The mixed use of the primary and secondary particles is beneficial for further adjusting the compaction density of the positive electrode active material.

[0196] In some embodiments, the longest average particle size of the primary particle morphology of the lithium-containing phosphate is 300-800 nm. This helps shorten the ion transmission distance and thus improve the fast charging performance. The longest average particle size of the primary particle morphology of the lithium-containing phosphate can be 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, or a numerical range consisting of any two of the above values.

[0197] In some embodiments, the longest average particle size of the lithium-containing phosphate in the secondary particle morphology is 8μm to 15μm. Secondary particles are generally composed of lithium-containing phosphates with smaller primary particles, which helps to shorten the ion transmission distance. The longest average particle size of the lithium-containing phosphate in the secondary particle morphology can be 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, or a numerical range consisting of any two of the above values.

[0198] In some embodiments, the secondary particles of the lithium-containing phosphate are spherical or quasi-spherical. Spherical refers to a material with a sphericity of 1, and quasi-spherical refers to a material with a sphericity close to 1 but not 1.

[0199] In some embodiments, the volume distribution particle size Dv50 of the lithium-containing phosphate is 5 to 15 μm. The volume distribution particle size Dv50 of the lithium-containing phosphate can be 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, or a numerical range consisting of any two of the above values.

[0200] An embodiment of the present application also provides a battery device, including the battery cell provided in the present application.

[0201] As the electrical device, a battery cell, a battery module or a battery pack can be selected according to its usage requirements.

[0202] The electric device may be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the electric device's requirements for high power and high energy density of battery cells, a battery pack or battery module may be used.

[0203] Another example device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be lightweight and thin, and may use a battery cell as a power source.

[0204] An embodiment of the present application also provides an electrical device, including the battery device provided in the present application.

[0205] Example

[0206] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0207] Example 1

[0208] 1. Preparation of positive electrode sheet

[0209] The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer. The positive electrode film layer is arranged on both sides of the positive electrode current collector, and the positive electrode current collector is aluminum foil.

[0210] The positive electrode film layer includes a positive electrode slurry (the solvent is N-methylpyrrolidone NMP) uniformly coated on the surface of the positive electrode current collector, and then dried and cold pressed to form a film layer. The positive electrode film layer includes a positive electrode active material, a binder polyvinylidene fluoride (PVDF), and a conductive agent acetylene black in a weight ratio of 90:5:5.

[0211] The positive electrode active material includes lithium iron phosphate particles and metal elements located in the lithium iron phosphate particles. The metal elements include Al, V, and Ti. Among them, the mass proportion of Al, V, and Ti in the lithium iron phosphate particles is 0.15%.

[0212] The lithium iron phosphate particles consist of primary particles and secondary particles formed by agglomeration of the primary particles. The secondary particles are spherical or quasi-spherical in shape. The primary particles have an average maximum diameter of 600 nm, while the secondary particles have an average maximum diameter of 10 μm. The volume-distributed particle size (Dv50) of the lithium iron phosphate particles is 7 μm.

[0213] The surface density of the single-sided positive electrode film layer is 0.28g / 1540.25mm 2 .

[0214] When the state of charge (SOC) of the battery cell is 0%, the compaction density of the single-sided positive electrode film layer of the positive electrode sheet is 2.4 g / cc.

[0215] The porosity of the positive electrode sheet is 25%.

[0216] 2. Preparation of negative electrode sheet

[0217] The negative electrode plate includes a negative electrode current collector and a negative electrode film layer. The negative electrode film layer is arranged on both sides of the negative electrode current collector, and the negative electrode current collector is copper foil.

[0218] The negative electrode film layer includes a first film layer and a second film layer formed by uniformly coating the negative electrode slurry (the solvent is deionized water) on the surface of the negative electrode current collector, drying and cold pressing.

[0219] The first film layer, disposed on the surface of the negative electrode current collector, comprises a first negative electrode active material, a conductive agent, acetylene black, a negative electrode binder, and a thickener, sodium carboxymethyl cellulose, in a mass ratio of 96.5:0.5:2:1. The negative electrode active material comprises graphite and silicon oxide, with silicon comprising 5% by mass. The graphite comprises artificial graphite and a carbon coating layer, which is coated on the surface of the artificial graphite. The carbon coating layer is 200 nm thick and has a graphitization degree of 92%. The graphite has an average maximum particle size of 12 μm.

[0220] The second film layer, applied to the surface of the negative electrode current collector, comprises a negative electrode active material, a conductive agent, acetylene black, a negative electrode binder, and a thickener, sodium carboxymethyl cellulose, in a mass ratio of 96.5:0.5:2:1. The negative electrode active material comprises graphite and silicon oxide, with silicon accounting for 5% by mass of the first negative electrode active material. The graphite comprises artificial graphite and a carbon coating layer, which is coated on the surface of the artificial graphite. The carbon coating layer is 200 nm thick and has a graphitization degree of 92%. The graphite has an average maximum particle size of 9 μm.

[0221] The thickness of the first film layer is 50% of the total thickness of the negative electrode film layer, and the thickness of the second film layer is 50% of the total thickness of the negative electrode film layer.

[0222] The surface density of the single-sided negative electrode film is 0.13g / 1540.25mm 2 .

[0223] When the state of charge (SOC) of the battery cell is 0%, the compaction density of the single-sided negative electrode film layer of the negative electrode sheet is 1.4 g / cc.

[0224] The porosity of the negative electrode sheet is 28%.

[0225] 3. Isolation film

[0226] The separator is a 7 μm polyethylene film layer.

[0227] 4. Preparation of electrolyte

[0228] The electrolyte includes an organic solvent, a lithium salt and an additive. After mixing the components of each organic solvent, the lithium salt and the additive are added to prepare an electrolyte. The organic solvent includes ethyl acrylate, dimethyl carbonate and propylene carbonate. Based on the total mass of the electrolyte, the mass proportion of ethyl acrylate is 20%, the mass proportion of dimethyl carbonate is 20%, and the mass proportion of propylene carbonate is 40%. The lithium salt is lithium hexafluorophosphate. Based on the total mass of the electrolyte, the mass proportion of lithium hexafluorophosphate is 15%. The additives include lithium difluorophosphate and vinylene carbonate. Based on the total mass of the electrolyte, the mass proportion of lithium difluorophosphate is 1%, and the mass proportion of vinylene carbonate is 4%.

[0229] 5. Preparation of battery cells

[0230] The above-mentioned positive electrode sheets, isolation membranes, and negative electrode sheets are stacked in order, so that the isolation membrane is located between the positive electrode sheets and the negative electrode sheets to play an isolating role, thereby obtaining a laminated electrode assembly, wherein multiple positive electrode sheets and multiple negative electrode sheets are stacked in the third direction, and the positive electrode tabs and the negative electrode tabs are respectively located at the two side ends in the second direction of the electrode assembly.

[0231] The electrode assembly is placed in a shell, which includes a shell and a top cover covering a port of the shell in a first direction. A positive electrode column and a negative electrode column are arranged on the top cover along a second direction. After baking, the electrolyte is injected, and the battery cell is obtained through vacuum packaging, standing, formation, shaping and other processes.

[0232] In this embodiment, a dimension H1 of the battery cell in the first direction is 100 mm; a dimension W1 of the battery cell in the second direction is 300 mm; and a dimension T1 of the battery cell in the third direction is 50 mm.

[0233] The positive electrode connector includes a first main portion and a first bent portion arranged at an angle. The first bent portion is provided with a first welding hole for the positive electrode column to pass through and connect, and a first annular welding portion is formed between the first welding hole and the positive electrode column. The first main portion is electrically connected to the positive electrode tab. The dimension d1 of the first main portion in the second direction is 2.5 mm, and the dimension d2 of the first bent portion in the first direction is 2.5 mm.

[0234] The first main body has a dimension of 25 mm in the first direction, and the sum of the dimension of the first main body in the first direction and the dimension of the first bent portion in the second direction is 60 mm. The first bent portion includes a first welding section and a first connecting section. The first welding section is provided with a first welding hole. The dimension of the first connecting section in the first direction is 2.5 mm. The dimension of the first welding section in the first direction is 1.5 mm.

[0235] The negative electrode connector includes a second main body and a second bent portion arranged at an angle, the second bent portion is provided with a second welding hole for the negative electrode column to pass through and connect, and a second annular welding portion is formed between the second welding hole and the negative electrode column; the second main body is electrically connected to the negative electrode tab; the dimension d3 of the second main body in the second direction is 2 mm, and the dimension d4 of the second bent portion in the first direction is 2 mm.

[0236] The second main body has a dimension of 25 mm in the first direction, and the sum of the dimension of the second main body in the first direction and the dimension of the second bent portion in the second direction is 60 mm. The second bent portion includes a second welding section and a second connecting section, with a second welding hole provided in the second welding section. The dimension of the second connecting section in the first direction is 2 mm, and the dimension of the second welding section in the first direction is 1.0 mm.

[0237] The diameter of the positive pole is 15mm and the diameter of the negative pole is 15mm.

[0238] Batteries were prepared in Examples 2-7 and Comparative Examples 1-2 in a manner similar to that of Example 1. The differences are shown in Tables 1 and 3.

[0239] Comparative Example 3

[0240] This comparative example uses a similar method to prepare a battery in Example 1, but differs from Example 1 in that:

[0241] The positive electrode sheet, the separator, and the negative electrode sheet are stacked in order, so that the separator is located between the positive electrode sheet and the negative electrode sheet to play an isolating role, thereby obtaining a laminated electrode assembly, wherein multiple positive electrode sheets and multiple negative electrode sheets are stacked in the third direction, the positive electrode tab and the negative electrode tab are both located at the same end (top) in the first direction of the electrode assembly, and the positive electrode tab and the negative electrode tab are spaced apart.

[0242] The electrode assembly is placed in a housing, which includes a shell and a top cover covering a port of the shell in a first direction. The top cover is provided with a positive electrode column and a negative electrode column along a second direction. The positive and negative electrode tabs are positioned adjacent to the top cover, with the positive tab adjacent to the positive electrode column and the negative tab adjacent to the negative electrode column. After baking, the electrolyte is injected, and the battery cell is obtained through vacuum packaging, resting, formation, and shaping processes.

[0243] In this embodiment, a dimension H1 of the battery cell in the first direction is 100 mm; a dimension W1 of the battery cell in the second direction is 300 mm; and a dimension T1 of the battery cell in the third direction is 50 mm.

[0244] The positive electrode connector is a solid rectangular piece connected between the positive electrode tab and the positive electrode column. The size of the positive electrode connector in the first direction is 1.2 mm.

[0245] The negative electrode connector is a solid rectangular piece connected between the positive electrode tab and the negative electrode column. The dimension of the negative electrode connector in the first direction is 0.8 mm.

[0246] The diameter of the positive pole is 15mm and the diameter of the negative pole is 15mm.

[0247] The size of the positive electrode tab in the second direction is 30 mm, and the size of the negative electrode tab in the second direction is 30 mm.

[0248] Performance testing:

[0249] (1) Temperature rise difference of positive electrode column:

[0250] Temperature sensors are placed on the battery cell terminals to monitor the temperature changes during charge and discharge at a 4C rate. At 25°C, the assembled battery is charged, and the initial temperature, T1, is recorded. Then, the battery is fully charged at a 4C rate, and the temperature, T2, is recorded. The difference in the positive terminal temperature is the difference between T2 and T1.

[0251] (2) Energy density test:

[0252] At 25°C, the assembled battery cells were fully charged at a 0.5C rate and fully discharged at a 0.5C rate, and the actual discharge energy at this time was recorded; at 25°C, the battery was weighed using an electronic balance; the ratio of the battery's actual 0.5C discharge energy to the battery weight was the battery's energy density.

[0253] Table 1

[0254]

[0255] In Table 1, the dimension d2 of the first bending portion in the first direction refers to the maximum dimension of the first bending portion in the first direction, and the dimension d4 of the second bending portion in the first direction refers to the maximum dimension of the second bending portion in the first direction. The units of each dimension in Table 1 are mm.

[0256] In Comparative Example 1, the thickness of the positive electrode connector is relatively smaller, and the difference in the temperature rise of the positive electrode pole is too large. In Comparative Example 2, the thickness of the negative electrode connector is relatively smaller, and the difference in the temperature rise of the positive electrode pole is too large.

[0257] In Examples 1-5 of the present application, the dimension d1 of the first main portion in the second direction, the dimension d2 of the first bent portion in the first direction, the dimension d3 of the second main portion in the second direction, and the dimension d4 of the second bent portion in the first direction are adjusted within appropriate ranges. That is, the thickness of the positive electrode connector and the thickness of the negative electrode connector are adjusted within appropriate ranges, which helps reduce the temperature increase of the positive electrode post. This helps improve the reliability of stable high current flow in fast charging scenarios.

[0258] As can be seen from Examples 1-5, as the thickness of the positive or negative connector increases, the temperature rise difference of the positive electrode post decreases. However, in the present embodiments, excessive thickness of the positive or negative connector can hinder or even prevent welding of the positive connector to the positive electrode post (or vice versa). Therefore, the dimensions d1, d2, d3, and d4 should not be too large.

[0259] Table 2

[0260]

[0261] From the energy density data of Example 1 and Comparative Example 3 in Table 2, it can be seen that in Comparative Example 3, both the positive electrode tab and the negative electrode tab are arranged on the top of the electrode assembly, which occupies more internal space of the battery cell, resulting in a decrease in the energy density of the battery cell.

[0262] Table 3

[0263]

[0264] In Table 3, M1 refers to the sum of the dimensions of the first main body in the first direction and the dimensions of the first bent portion in the second direction. M2 refers to the sum of the dimensions of the second main body in the first direction and the dimensions of the second bent portion in the second direction. All dimensions in Table 3 are in mm.

[0265] As can be seen from Examples 1, 6-7, adjusting M1, M2, the positive electrode column diameter, and the negative electrode column diameter within appropriate ranges can help reduce the temperature rise of the positive electrode column, thereby improving the reliability of high current stable passage in fast charging scenarios.

[0266] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A battery cell, characterized in that: The size of the battery cell in the first direction is 80-130 mm; the size of the battery cell in the second direction is 200-350 mm; the ratio of the size of the battery cell in the second direction to the size of the battery cell in the first direction is 1.5-4.4; The battery cell includes a housing, an electrode assembly, a positive electrode connector and a negative electrode connector: The housing includes a shell and a top cover covering a port of the shell in a first direction, a positive electrode column and a negative electrode column are provided on the top cover along a second direction, and the electrode assembly is provided in the shell; The electrode assembly includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked in a third direction, and a positive electrode tab and a negative electrode tab respectively located at both side ends of the electrode assembly in a second direction; wherein the positive electrode active material of the positive electrode sheets includes a lithium-containing phosphate, and the negative electrode active material of the negative electrode sheets includes graphite; The positive electrode connector includes a first main portion and a first bent portion arranged at an angle. The first bent portion is provided with a first welding hole for the positive electrode column to pass through and connect, and a first annular welding portion is formed between the first welding hole and the positive electrode column. The first main portion is electrically connected to the positive electrode tab. The first main portion has a dimension of 1.5 to 3.0 mm in the second direction, and the first bent portion has a dimension of 1.5 to 3.0 mm in the first direction. The negative electrode connector includes a second main body and a second bent portion arranged at an angle, the second bent portion is provided with a second welding hole for the negative electrode column to pass through and connect, and a second annular welding portion is formed between the second welding hole and the negative electrode column; the second main body is electrically connected to the negative electrode tab; the second main body has a dimension of 1.2 to 2.5 mm in the second direction, and the second bent portion has a dimension of 1.2 to 2.5 mm in the first direction. The first direction is a height direction of the battery cell, the second direction is a width direction of the battery cell, and the third direction is a thickness direction of the battery cell.

2. The battery cell according to claim 1, wherein: The sum of the size of the first main body in the first direction and the size of the first bending portion in the second direction is 50 mm to 90 mm.

3. The battery cell according to claim 1 or 2, characterized in that: The sum of a size of the second main body in the first direction and a size of the second bent portion in the second direction is 50 mm to 90 mm.

4. The battery cell according to claim 1, wherein: The size of the first main body in the first direction is 25% to 50% of the size of the battery cell in the first direction.

5. The battery cell according to claim 1, characterized in that The size of the second main body in the first direction is 25% to 50% of the size of the battery cell in the first direction.

6. The battery cell according to claim 1, characterized in that A size of the first main body in the third direction is smaller than a size of the battery cell in the third direction, and an absolute value of a difference between the size of the first main body in the third direction and the size of the battery cell in the third direction is 5 mm to 15 mm.

7. The battery cell according to claim 1, characterized in that A size of the second main body in the third direction is smaller than a size of the battery cell in the third direction, and an absolute value of a difference between the size of the second main body in the third direction and the size of the battery cell in the third direction is 5 mm to 15 mm.

8. The battery cell according to claim 1, wherein: At least one positive electrode tab is provided on each of the positive electrode sheets, and each of the positive electrode tabs is provided at a first side end of the positive electrode sheet in the second direction, and a size of the positive electrode tab in the first direction is 90% to 100% of a size of the positive electrode sheet in the first direction.

9. The battery cell according to claim 1, characterized in that At least one negative electrode tab is provided on each of the negative electrode plates, and each of the negative electrode tabs is provided at the second side end of the negative electrode plate in the second direction, and the size of the negative electrode tab in the first direction is 90% to 100% of the size of the negative electrode plate in the first direction.

10. The battery cell according to claim 1, characterized in that The first bending portion includes: a first welding section, wherein a first welding hole is provided on the first welding section; and A first connecting segment connects the first welding segment and the first main body; wherein the size of the first connecting segment in the first direction is larger than the size of the first welding segment in the first direction.

11. The battery cell according to claim 10, characterized in that The size of the first connecting segment in the first direction is 1.5-3.0 mm.

12. The battery cell according to claim 10 or 11, characterized in that: The size of the first welding segment in the first direction is 1.0-2.5 mm.

13. The battery cell according to claim 10, characterized in that On the side of the first bending portion facing away from the top cover, the first welding section is recessed relative to the first connecting section; the first welding section also includes an insulating sheet that at least partially covers the surface of the first welding section, and the insulating sheet is arranged between the first welding section and the electrode assembly.

14. The battery cell according to claim 1, characterized in that The second bent portion of the negative electrode connector includes: a second welding section, wherein a second welding hole is provided on the second welding section; and The second connecting segment connects the second welding segment and the second main body; wherein the size of the second connecting segment in the first direction is larger than the size of the second welding segment in the first direction.

15. The battery cell according to claim 14, characterized in that The size of the second connecting segment in the first direction is 1.2-2.5 mm.

16. The battery cell according to claim 14 or 15, characterized in that: The size of the second welding section in the first direction is 1.0-2.0 mm.

17. The battery cell according to claim 14, characterized in that On the side of the second bending portion facing away from the top cover, the second welding section is recessed relative to the second connecting section; the second welding section also includes an insulating sheet that at least partially covers the surface of the second welding section, and the insulating sheet is arranged between the second welding section and the electrode assembly.

18. The battery cell according to claim 1, characterized in that The diameter of the positive electrode column is 9-22 mm.

19. The battery cell according to claim 1, characterized in that The diameter of the negative electrode column is 9-22 mm.

20. The battery cell according to claim 1, characterized in that The top cover includes a first edge and a second edge in a second direction, and a distance between a central axis of the positive electrode column and the first edge is 15-35 mm; a distance between a central axis of the negative electrode column and the second edge is 15-35 mm.

21. The battery cell according to claim 1, characterized in that The positive electrode tab at least partially covers the first main body.

22. The battery cell according to claim 1, characterized in that The negative electrode tab at least partially covers the second main body.

23. The battery cell according to claim 1, characterized in that A heat-insulating film layer is provided between the negative electrode tab and the negative electrode connector.

24. The battery cell according to claim 1, characterized in that A heat insulation film layer is provided between the positive electrode tab and the positive electrode connector.

25. The battery cell according to claim 1, characterized in that A heat-insulating film layer is provided between the electrode assembly and the shell.

26. The battery cell according to claim 1, characterized in that A heat insulation film layer is provided between the electrode assembly and the top cover.

27. The battery cell according to claim 23, characterized in that The material of the thermal insulation film layer includes at least one of polyimide and polyethylene terephthalate.

28. The battery cell according to claim 23, characterized in that The thickness of the thermal insulation film layer is 10-100 μm.

29. The battery cell according to claim 1, characterized in that The size of the battery cell in the third direction is 30-50 mm.

30. The battery cell according to claim 1, characterized in that The negative electrode plate includes a negative electrode current collector and a negative electrode film layer located on at least one side of the negative electrode current collector, wherein the negative electrode film layer includes a first film layer and a second film layer, wherein the first film layer is disposed on at least one surface of the negative electrode current collector, and the second film layer is disposed on a surface of the first film layer facing away from the current collector; The first film layer contains a first negative electrode active material; the second film layer contains a second negative electrode active material; the longest average particle size of graphite in the second negative electrode active material is smaller than the longest average particle size of graphite in the first negative electrode active material.

31. The battery cell according to claim 30, characterized in that The longest average particle size of the graphite in the first negative electrode active material is 7 to 18 μm.

32. The battery cell according to claim 30 or 31, characterized in that: The graphite in the first negative electrode active material includes at least one of artificial graphite and natural graphite.

33. The battery cell according to claim 30, characterized in that The graphite in the first negative electrode active material includes graphite in a secondary particle morphology.

34. The battery cell according to claim 30, characterized in that The volume distribution particle size Dv50 of the graphite in the first negative electrode active material is 7-15 μm.

35. The battery cell according to claim 30, characterized in that The graphite in the first negative electrode active material includes a carbon coating layer, and the thickness of the carbon coating layer is 100-500 nm.

36. The battery cell according to claim 30, characterized in that The graphite in the first negative electrode active material has a graphitization degree of 90-94%.

37. The battery cell according to claim 30, characterized in that The first negative electrode active material further includes a silicon material, and the mass proportion of silicon element in the silicon material in the first negative electrode active material is 0.5-10%.

38. The battery cell according to claim 30, characterized in that The longest average particle size of the graphite in the second negative electrode active material is 6 to 10 μm.

39. The battery cell according to claim 30, characterized in that The graphite in the second negative electrode active material includes at least one of artificial graphite and natural graphite.

40. The battery cell according to claim 30, characterized in that The graphite in the second negative electrode active material includes graphite in a secondary particle morphology.

41. The battery cell according to claim 30, characterized in that The volume distribution particle size Dv50 of the graphite in the second negative electrode active material is 7-15 μm.

42. The battery cell according to claim 30, characterized in that The graphite in the second negative electrode active material includes a carbon coating layer, and the thickness of the carbon coating layer is 100-500 nm.

43. The battery cell according to claim 30, characterized in that The graphite in the second negative electrode active material has a graphitization degree of 90-94%.

44. The battery cell according to claim 30, characterized in that The second negative electrode active material further includes a silicon material, and the mass proportion of silicon element in the silicon material in the second negative electrode active material is 0.5-10%.

45. The battery cell according to claim 30, characterized in that The thickness of the first film layer is 30% to 70% of the total thickness of the negative electrode film layer.

46. ​​The battery cell according to claim 30, characterized in that The thickness of the second film layer is 30% to 70% of the total thickness of the negative electrode film layer.

47. The battery cell according to claim 1, characterized in that When the state of charge (SOC) of the battery cell is 0%, the compaction density of the negative electrode film layer on a single side of the negative electrode plate is 1.3-1.52 g / cc.

48. The battery cell according to claim 1, characterized in that The surface density of the negative electrode film layer on a single side of the negative electrode plate is 0.12-0.18 g / 1540.25 mm 2 .

49. The battery cell according to claim 1, characterized in that When the state of charge (SOC) of the battery cell is 0%, the compaction density of the positive electrode film layer on a single side of the positive electrode sheet is 2.3-2.6 g / cc.

50. The battery cell according to claim 1, characterized in that The surface density of the single-sided positive electrode film layer of the positive electrode plate is 0.25~0.33g / 1540.25mm 2 .

51. The battery cell according to claim 1, characterized in that The lithium-containing phosphate includes lithium iron phosphate, the lithium iron phosphate includes a metal element, and the metal element includes at least one of aluminum, titanium, and vanadium.

52. The battery cell according to claim 51, characterized in that The metal element includes aluminum, and the mass proportion of the aluminum in the lithium-containing phosphate is 0.02% to 0.25%.

53. The battery cell according to claim 51 or 52, characterized in that: The metal element includes titanium, and the mass proportion of the titanium in the lithium-containing phosphate is 0.15% to 0.35%.

54. The battery cell according to claim 51, characterized in that The metal element includes vanadium, and the mass proportion of the vanadium in the lithium-containing phosphate is 0.03% to 0.2%.

55. The battery cell according to claim 1, characterized in that The lithium-containing phosphate includes lithium-containing phosphate in the form of primary particles and lithium-containing phosphate in the form of secondary particles.

56. The battery cell according to claim 55, characterized in that The longest average particle size of the lithium-containing phosphate in the primary particle morphology is 300-800 nm.

57. The battery cell according to claim 55 or 56, characterized in that: The longest average particle size of the lithium-containing phosphate in the secondary particle morphology is 8 μm to 15 μm.

58. The battery cell according to claim 55, characterized in that The secondary particles of the lithium-containing phosphate are spherical or quasi-spherical.

59. The battery cell according to claim 1, characterized in that The volume distribution particle size Dv50 of the lithium-containing phosphate is 5-15 μm.

60. A battery device, characterized in that: Comprising the battery cell according to any one of claims 1 to 59.

61. An electrical device, characterized in that: Comprising a battery device as claimed in claim 60.

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