Battery cell, battery device, and electric device

Abstract

The invention discloses a battery monomer, a battery device and a power utilization device. The size of each battery monomer in the first direction is 80-130 mm; the size of the first guide rail 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 connecting piece comprises a first main body part and a first bending part which are arranged at an included angle; the size of the first main body part in the second direction is 1.5-3.0 mm, and the size of the first bending part in the first direction is 1.5-3.0 mm; the negative electrode connecting piece comprises a second main body part and a second bending part which are arranged at an included angle; the size of the second main body part in the second direction is 1.2-2.5 mm, and the size of the second bending part in the first direction is 1.2-2.5 mm. According to the technical scheme, the structure is more reasonable, and the energy density and the fast charging reliability of the battery are further improved.

Description

[0001] This application claims the priority of the PCT international application "Battery Cell, Battery Device, and Electrical Device" with the application number PCT / CN2025 / 077647 filed on February 17, 2025. The entire content of this application is incorporated into this application by reference. Technical Field

[0002] This application relates to the technical field of batteries, and specifically relates to a battery cell, a battery device, and an electrical device. Background Art

[0003] In recent years, with the increasingly wide application range of batteries, batteries are widely used in energy storage power systems such as hydraulic, thermal, wind, and solar power stations, as well as in multiple fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace.

[0004] With the wide application of batteries, higher requirements are put forward for the energy density and fast charging reliability of batteries. However, the structure of the battery cell is not entirely reasonable, so the energy density and fast charging reliability of the battery need to be further improved. Summary of the Invention

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

[0006] In a first aspect, this application provides a battery cell. 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: Among them, the housing includes a shell and a top cover covering one end port of the shell in the first direction. A positive electrode post and a negative electrode post are arranged on the top cover along the second direction, and the electrode assembly is arranged in the housing; The electrode assembly includes a plurality of positive electrode plates and a plurality of negative electrode plates stacked in the third direction, and a positive electrode tab and a negative electrode tab respectively located at both ends of the electrode assembly in the second direction; Among them, the positive active material of the positive electrode plate includes lithium-containing phosphate, and the negative active material of the negative electrode plate includes graphite; The positive electrode connector includes a first main body portion and a first bending portion arranged at an angle. The first bending portion is provided with a first welding hole for the positive electrode post to pass through and be connected, and a first annular welding portion is formed between the first welding hole and the positive electrode post. The first main body portion is electrically connected to the positive electrode tab; the size of the first main body portion in the second direction is 1.5 - 3.0 mm, and the size of the first bending portion in the first direction is 1.5 - 3.0 mm; The negative electrode connecting member includes a second main body portion and a second bending portion disposed at an angle. The second bending portion is provided with a second welding hole for the negative electrode post to pass through and connect, and a second annular welding portion is formed between the second welding hole and the negative electrode post; the second main body portion is electrically connected to the negative electrode tab; the dimension of the second main body portion in the second direction is 1.2 - 2.5 mm, and the dimension of the second bending portion in the first direction is 1.2 - 2.5 mm.

[0007] In the technical solution of the present application, the battery cell adopts the above - mentioned appropriate dimensions in the first direction and the second direction, and cooperates with the positive electrode tab and the negative electrode tab arranged at both ends in the second direction of the electrode assembly, that is, the electrode tabs are led out from the short sides on different sides, which reasonably and effectively improves the space utilization rate of the battery cell, thereby being beneficial to obtaining a high energy density. Through the cooperation of the above - mentioned dimensions of the first main body portion, the first bending portion of the positive electrode connecting member, the second main body portion, and the second bending portion of the negative electrode connecting member, it is beneficial to improve the current - carrying capacity, thereby improving the reliability of stable passage of high current in the fast - charging scenario. And the first annular welding portion and the second annular welding portion formed in the technical solution of the present application are beneficial to improving the stability and firmness of welding, and are beneficial to improving the reliability of stable passage of high current.

[0008] In any embodiment, the sum of the dimension of the first main body portion in the first direction and the dimension of the first bending portion in the second direction is 50 mm - 90 mm. Thus, it is beneficial to optimize the electron transmission path, thereby reducing the internal resistance of the positive electrode connecting member.

[0009] In any embodiment, the sum of the dimension of the second main body portion in the first direction and the dimension of the second bending portion in the second direction is 50 mm - 90 mm. Thus, it is beneficial to optimize the electron transmission path, thereby reducing the internal resistance of the negative electrode connecting member.

[0010] In any embodiment, the dimension of the first main body portion in the first direction is 25% - 50% of the dimension of the battery cell in the first direction. Thus, it is beneficial to optimize the electron transmission path, thereby reducing the internal resistance of the positive electrode connecting member.

[0011] In any embodiment, the dimension of the second main body portion in the first direction is 25% - 50% of the dimension of the battery cell in the first direction. Thus, it is beneficial to optimize the electron transmission path, thereby reducing the internal resistance of the negative electrode connecting member.

[0012] In any embodiment, the dimension of the first main body portion in the third direction is less 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 portion in the third direction and the dimension of the battery cell in the third direction is 5 mm - 15 mm. Thus, it is beneficial to the effective contact between the positive electrode connecting member and the positive electrode tab.

[0013] In any embodiment, the size of the second main body in the third direction is smaller than the size of the battery cell in the third direction, and the absolute value of the 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, thereby facilitating effective contact between the negative electrode connector and the positive electrode tab.

[0014] In any embodiment, at least one positive electrode tab is disposed on each positive electrode sheet, each positive electrode tab is disposed at a first side end of the positive electrode sheet in the second direction, and the size of the positive electrode tab in the first direction is 90% to 100% of the size of the positive electrode sheet in the first direction. This is conducive to increasing the contact area between the positive electrode tab and the positive electrode sheet, thereby reducing the resistance when current passes through.

[0015] In any embodiment, at least one negative electrode tab is disposed on each negative electrode plate, each negative electrode tab is disposed 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. This is conducive to increasing the contact area between the negative electrode tab and the positive electrode plate, thereby reducing the resistance when current passes through.

[0016] In any embodiment, the first bending portion includes a first welding section and a first connecting section, the first welding section is provided with a first welding hole, and the first connecting section connects the first welding section and the first main body; wherein the size of the first connecting section in the first direction is larger than the size of the first welding section in the first direction. The first welding section is relatively thin, which is conducive to improving the reliability of welding, and the first connecting section is relatively thick, which is conducive to ensuring the flow capacity.

[0017] In any embodiment, the size of the first connecting section in the first direction is 1.5-3.0 mm, which is beneficial to improve the reliability of stable passage of high current in fast charging scenarios.

[0018] In any embodiment, the size 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 passage.

[0019] In any embodiment, on the 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 also includes an insulating sheet at least partially covering the surface of the first welding section, and the insulating sheet is arranged between the first welding section and the electrode assembly. The arrangement of the insulating sheet can prevent welding slag from falling into the gap between the electrode assemblies when welding the positive electrode column and the positive electrode connector.

[0020] In any embodiment, the second bent portion of the negative electrode connector includes a second welding section and a second connecting section, the second welding section is provided with a second welding hole, the second connecting section connects the second welding section and the second main body, wherein the size of the second connecting section in the first direction is greater than the size of the second welding section in the first direction. The second welding section is relatively thin, which is conducive to improving the reliability of welding, and the second connecting section is relatively thick, which is conducive to ensuring the flow capacity.

[0021] In any embodiment, the size of the second connecting section in the first direction is 1.2-2.5 mm, which is beneficial to improving the reliability of stable high current passing in fast charging scenarios.

[0022] 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 passage.

[0023] In any embodiment, on the 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 also includes an insulating sheet at least partially covering the surface of the second welding section, and the insulating sheet is arranged between the second welding section and the electrode assembly. The arrangement of the insulating sheet can prevent welding slag from falling into the gap between the electrode assemblies when the negative electrode column and the negative electrode connector are welded.

[0024] In any embodiment, the diameter of the positive electrode column is 9-22 mm, which is helpful to improve the reliability of high current stable passage in fast charging scenarios.

[0025] In any embodiment, the diameter of the negative electrode column is 9-22 mm, which is beneficial to improve the reliability of high current stable passage in fast charging scenarios.

[0026] 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 position setting of the positive electrode column and the negative electrode column is conducive to making the battery structure more reasonable and optimizing the electron transmission path.

[0027] In any embodiment, the positive electrode tab at least partially covers the first main body, thereby facilitating increasing the contact area between the positive electrode tab and the positive electrode connector and reducing the internal resistance.

[0028] In any embodiment, the negative electrode tab at least partially covers the second main body, thereby facilitating increasing the contact area between the negative electrode tab and the negative electrode connector and reducing the internal resistance.

[0029] In any embodiment, a heat insulation film layer is provided between the negative electrode tab and the negative electrode connection member. Thereby, it is beneficial to isolate heat and improve the reliability of the battery.

[0030] In any embodiment, a heat insulation film layer is provided between the positive electrode tab and the positive electrode connection member. Thereby, it is beneficial to isolate heat and improve the reliability of the battery.

[0031] In any embodiment, a heat insulation film layer is provided between the electrode assembly and the housing. Thereby, it is beneficial to isolate heat and improve the reliability of the battery.

[0032] In any embodiment, a heat insulation film layer is provided between the electrode assembly and the top cover. Thereby, it is beneficial to isolate heat and improve the reliability of the battery.

[0033] In any embodiment, the material of the heat insulation film layer includes at least one of polyimide and polyethylene terephthalate. The heat insulation film layer of the above materials is beneficial to isolate heat and improve the reliability of the battery.

[0034] In any embodiment, the thickness of the heat insulation film layer is 10 - 100 μm. At this appropriate thickness, it is beneficial to reasonably utilize the battery space and is beneficial to isolate heat and improve the reliability of the battery.

[0035] In any embodiment, the size of the battery cell in the third direction is 30 - 50 mm. At this appropriate thickness, it is beneficial to reasonably utilize the battery space and exert the high energy density of the battery.

[0036] 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 disposed on at least one surface of the negative electrode current collector, and the second film layer is disposed 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 average longest diameter particle size of the second negative electrode active material is smaller than the average longest diameter particle size of the first negative electrode active material.

[0037] Thereby, the average longest diameter particle size of the active material used in the second film layer is relatively smaller, and the ion transport distance of ions in the second film layer is relatively shorter, which is beneficial to further improve the fast charging performance of the battery cell. And the average longest diameter particle size of the active material used in the first film layer is relatively larger, and the compaction density of the first film layer is relatively higher, which is beneficial to taking into account good energy density.

[0038] In any embodiment, the average longest diameter particle size of the first negative electrode active material is 7 - 18 μm. Thereby, it is beneficial to exert the relatively higher compaction density of the first film layer.

[0039] In any embodiment, the first negative electrode active material includes at least one of artificial graphite and natural graphite.

[0040] In any embodiment, the first negative electrode active material includes a negative electrode active material having a secondary particle morphology.

[0041] In any embodiment, the volume distribution particle size Dv50 of the first negative electrode active material is 7 to 15 μm.

[0042] In any embodiment, the first negative electrode active material includes a carbon coating layer, and the thickness of the carbon coating layer is 100 to 500 nm. The carbon coating layer is beneficial to improving the conductivity of the negative electrode active material.

[0043] In any embodiment, the graphitization degree of the first negative electrode active material is 90 to 94%.

[0044] In any embodiment, the first negative electrode active material includes a silicon material, and the mass ratio of silicon element in the silicon material in the first negative electrode active material is 0.5 to 10%. The addition of the silicon material is beneficial to further improving the energy density of the battery cell.

[0045] In any embodiment, the average longest diameter particle size of the second negative electrode active material is 6 to 10 μm. Thus, it is beneficial to exert the effect that the ion transport distance in the second film layer is relatively shorter.

[0046] In any embodiment, the second negative electrode active material includes at least one of artificial graphite and natural graphite.

[0047] In any embodiment, the second negative electrode active material includes a negative electrode active material having a secondary particle morphology.

[0048] In any embodiment, the volume distribution particle size Dv50 of the second negative electrode active material is 7 to 15 μm.

[0049] In any embodiment, the second negative electrode active material includes a carbon coating layer, and the thickness of the carbon coating layer is 100 to 500 nm. The carbon coating layer is beneficial to improving the conductivity of the negative electrode active material.

[0050] In any embodiment, the graphitization degree of the second negative electrode active material is 90 to 94%.

[0051] In any embodiment, the second negative electrode active material includes a silicon material, and the mass ratio of silicon element in the silicon material in the second negative electrode active material is 0.5 to 10%. The addition of the silicon material is beneficial to further improving the energy density of the battery cell. In any implementation, the thickness of the first film layer is 30% to 70% of the total thickness of the negative electrode film layer. Thus, it is beneficial to play the role of the first film layer in taking into account the energy density of the battery cell.

[0052] In any implementation, the thickness of the second film layer is 30% to 70% of the total thickness of the negative electrode film layer. Thus, it is beneficial to further improve the fast charging performance of the battery cell.

[0053] In any implementation, under the condition that 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 plate is 1.3 to 1.52 g / cc. Thus, a suitable compaction density is beneficial to further adjust the porosity of the negative electrode plate within a suitable range.

[0054] In any implementation, the areal density of the single-sided negative electrode film layer of the negative electrode plate is 0.12 to 0.18 g / 1540.25 mm 2 . Thus, a suitable areal density is beneficial to further adjust the porosity of the negative electrode plate within a suitable range.

[0055] In any implementation, 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 plate is 2.3 to 2.6 g / cc. Thus, a suitable compaction density is beneficial to further adjust the porosity of the positive electrode plate within a suitable range.

[0056] In any implementation, the areal density of the single-sided positive electrode film layer of the positive electrode plate is 0.25 to 0.33 g / 1540.25 mm 2 . Thus, a suitable areal density is beneficial to further adjust the porosity of the positive electrode plate within a suitable range.

[0057] In any implementation, the lithium-containing phosphate includes lithium iron phosphate, and the lithium iron phosphate includes metal elements, and the metal elements include at least one of aluminum, titanium, and vanadium. Adding the above metal elements to lithium iron phosphate is beneficial to increasing the compaction density of the positive electrode active material.

[0058] In any implementation, the metal element includes aluminum, and the mass ratio of aluminum in the lithium-containing phosphate is 0.02% to 0.25%. Thus, it is beneficial to play the role of aluminum doping in increasing the compaction density of the positive electrode active material and further improving the cycle performance of the battery cell.

[0059] In any implementation, the metal element includes titanium, and the mass ratio of the titanium in the lithium-containing phosphate is 0.15% to 0.35%. Thus, 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.

[0060] In any embodiment, the metal element includes vanadium, and the mass ratio of vanadium in the lithium-containing phosphate is 0.03% to 0.2%. Thus, it is beneficial to play the role of vanadium doping in improving the tap density of the positive electrode active material and further improving the charge and discharge performance of the battery cell.

[0061] In any embodiment, the lithium-containing phosphate includes lithium-containing phosphate with a primary particle morphology and lithium-containing phosphate with a secondary particle morphology. The mixed use of primary particles and secondary particles is beneficial to further adjust the tap density of the positive electrode active material.

[0062] In any embodiment, the average longest diameter of the lithium-containing phosphate with a primary particle morphology is 300 to 800 nm. Thus, it is beneficial to shorten the ion transport distance, thereby improving the fast charging performance.

[0063] In any embodiment, the average longest diameter of the lithium-containing phosphate with a secondary particle morphology is 8 μm to 15 μm. The secondary particles are usually composed of lithium-containing phosphates of primary particles with smaller particle sizes, which is beneficial to shorten the ion transport distance.

[0064] In any embodiment, the lithium-containing phosphate with a secondary particle morphology is spherical or quasi-spherical.

[0065] In any embodiment, the volume distribution particle size Dv50 of the lithium-containing phosphate is 5 to 15 μm.

[0066] In a second aspect, the present application provides a battery device, including the battery cell of the first aspect of the present application.

[0067] In a third aspect, the present application provides an electrical device, including the battery device of the second aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a schematic structural diagram of a vehicle according to some embodiments of the present application; Figure 2 It is a schematic exploded view of a battery according to some embodiments of the present application; Figure 3 It is a schematic structural diagram of a battery cell according to some embodiments of the present application; Figure 4 It is a schematic exploded view of a battery cell according to some embodiments of the present application; Figure 5 It is a front view of a positive electrode connector in a battery cell according to some embodiments of the present application; Figure 6 It is a front view of a negative electrode connector in a battery cell according to some embodiments of the present application; Figure 7 It is a top view of a positive electrode connector in a battery cell according to some embodiments of the present application; Figure 8 Top view of the negative electrode connection member in the battery cell according to some embodiments of the present application; Figure 9 Front view of the positive electrode plate and the positive electrode tab in the battery cell according to some embodiments of the present application; Figure 10 Front view of the negative electrode plate and the negative electrode tab in the battery cell according to some embodiments of the present application; Figure 11 Front view of the top cover in the battery cell according to some embodiments of the present application.

[0069] Description of the reference numerals: 1000, vehicle; 100, battery, 200, controller, 300, motor; 10, box body, 11, first part, 12, second part; 20, battery cell, 21, outer shell, 21a, housing, 21b, top cover, 21c, positive electrode post, 21d, negative electrode post, 22, electrode assembly, 22a, positive electrode plate, 22b, negative electrode plate, 22c, positive electrode tab, 22d, negative electrode tab, 23, positive electrode connection member, 23a, first main body portion, 23b, first bent portion, 24, negative electrode connection member, 24a, second main body portion, 24b, second bent portion, 25, insulating sheet, 23b1, first welding section, 23b2, first connection section, 23b3, first welding hole, 24b1, second welding section, 24b2, second connection section, 24b3, second welding hole, H1, dimension of the battery cell in the first direction, W1, dimension of the battery cell in the second direction, T1, dimension of the battery cell in the third direction, d1, dimension of the first main body portion in the second direction, d2, dimension of the first bent portion in the first direction, d3, dimension of the second main body portion in the second direction, d4, dimension of the second bent portion in the first direction, d5, dimension of the first main body portion in the first direction, d6, dimension of the first bent portion in the second direction, d7, dimension of the second main body portion in the first direction, d8, dimension of the second bent portion in the second direction, d9, dimension of the first main body portion in the third direction, d10, dimension of the second main body portion in the third direction, d11, dimension of the positive electrode tab in the first direction, d12, dimension of the negative electrode tab in the first direction, d13, dimension of the first connection section in the first direction, d14, dimension of the first welding section in the first direction, d15, dimension of the second connection section in the first direction, d16, dimension of the second welding section in the first direction, d17, distance between the central axis of the positive electrode post and the first edge, d18, distance between the central axis of the negative electrode post and the second edge. Detailed implementation manners

[0070] Hereinafter, embodiments of the battery cell, battery device, and electrical device of the present application will be specifically described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary details are omitted. For example, there are cases where details of well-known matters are omitted and repeated descriptions of actually identical structures are omitted. This is to prevent the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the accompanying 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 recited in the claims.

[0071] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a particular range. The ranges defined in this way can include or exclude the end values and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 - 120 and 80 - 110 are listed for a specific parameter, ranges of 60 - 110 and 80 - 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1 - 3, 1 - 4, 1 - 5, 2 - 3, 2 - 4, and 2 - 5. In the present application, unless otherwise stated, the numerical range "a - b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0 - 5" means that all real numbers between "0 - 5" have been fully listed herein, and "0 - 5" is only an abbreviated representation of these numerical combinations. Additionally, when stating that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0072] If there is no special instruction, all embodiments and alternative embodiments of the present application can be combined with each other to form new technical solutions.

[0073] If there is no special instruction, all technical features and alternative technical features of the present application can be combined with each other to form new technical solutions.

[0074] If there is no special instruction, the "including" and "comprising" mentioned in the present application mean open-ended or can also be closed-ended. For example, the "including" and "comprising" can mean that other components not listed can also be included or comprised, or can mean only the components listed are included or comprised.

[0075] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs; the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit this application; the terms "comprising" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0076] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, "a plurality of" means more than two, unless otherwise specifically defined.

[0077] Referring to "embodiments" herein means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0078] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0079] In the description of the embodiments of this application, the term "a plurality of" refers to more than two (including two). Similarly, "a plurality of groups" refers to more than two groups (including two groups), and "a plurality of pieces" refers to more than two pieces (including two pieces).

[0080] In the description of the embodiments of this application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of this application and simplifying the description, rather than indicating or implying that the indicated device or element 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 this application.

[0081] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral body; it can also be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

[0082] The battery cell disclosed in the embodiments of the present application can be used in an electrical device that uses a battery as a power source or various energy storage systems that use a battery as an energy storage element. The electrical device can be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric aircraft toy, and the like. The spacecraft can include an airplane, a rocket, a space shuttle, a spaceship, and the like.

[0083] For the convenience of description in the following embodiments, a vehicle 1000, which is an electrical device in an embodiment of the present application, is taken as an example for description.

[0084] Please refer to Figure 1 , Figure 1 , which is a schematic structural diagram of the vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be disposed at the bottom, the head, or the tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000. For example, the battery 100 can be used as an operating power source of the vehicle 1000. The vehicle 1000 can also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle 1000.

[0085] In some embodiments of the present application, the battery 100 can not only be used as an operating power source of the vehicle 1000, but also be used as a driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0086] Please refer to Figure 2 , Figure 2Exploded view of the battery 100 provided by some embodiments of the present application. The battery 100 includes a box body 10 and battery cells 20, and the battery cells 20 are accommodated in the box body 10. Among them, the box body 10 is used to provide an accommodation space for the battery cells 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 may include a first part 11 and a second part 12, the first part 11 and the second part 12 are covered with each other, and the first part 11 and the second part 12 jointly define an accommodation space for accommodating the battery cells 20. The second part 12 may be a hollow structure with one end open, and the first part 11 may be a plate-like structure. The first part 11 covers the open side of the second part 12 so that the first part 11 and the second part 12 jointly define an accommodation space; the first part 11 and the second part 12 may also both be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0087] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 can be connected in series, in parallel, or in a series-parallel combination. A series-parallel combination means that there are both series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a series-parallel combination together, and then the whole formed by the multiple battery cells 20 is accommodated in the box body 10; of course, the battery 100 can also be that multiple battery cells 20 are first connected in series, in parallel, or in a series-parallel combination to form a battery module form, and then multiple battery modules are connected in series, in parallel, or in a series-parallel combination to form a whole and are accommodated in the box body 10. The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component for realizing electrical connection among the multiple battery cells 20.

[0088] Among them, each battery cell 20 can be a secondary battery or a primary battery. The battery cell 20 can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc.

[0089] Some embodiments of the present application provide 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; 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.

[0090] The battery cell 20 includes a housing 21, an electrode assembly 22, a positive electrode connector 23, and a negative electrode connector 24: Among them, the housing 21 includes a housing body 21a and a top cover 21b covering one end port of the housing body 21a in the first direction. A positive electrode post 21c and a negative electrode post 21d are arranged on the top cover 21b along the second direction, and the electrode assembly 22 is arranged in the housing 21; The electrode assembly 22 includes a plurality of positive electrode plates 22a and a plurality of negative electrode plates 22b stacked in a third direction, and a positive electrode tab 22c and a negative electrode tab 22d respectively located at both ends of the electrode assembly 22 in a second direction; wherein, the positive active material of the positive electrode plate 22a includes lithium-containing phosphate, and the negative active material of the negative electrode plate 22b includes graphite; See 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 post 21c to pass through and connect. And a first annular welding portion is formed between the first welding hole 23b3 and the positive electrode post 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 to 3.0 mm, and the dimension d2 of the first bent portion in the first direction is 1.5 to 3.0 mm; See 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 to 2.5 mm, and the dimension d4 of the second bent portion in the first direction is 1.2 to 2.5 mm.

[0091] The embodiments of the present application define three reference directions. As Figure 3 shown in the figure, 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.

[0092] In the embodiments of the present application, at least one positive electrode tab 22c is provided on each positive electrode plate 22a, and at least one negative electrode tab 22d is provided on each negative electrode plate 22b. The plurality of positive electrode plates 22a and the plurality of negative electrode plates 22b are stacked so that each positive electrode tab 22c is located at the first side end of the electrode assembly 22 in the second direction, and each negative electrode tab 22d is located at the second side end of the electrode assembly 22 in the second direction, that is, the positive electrode tab and the negative electrode tab are respectively located at both ends of the electrode assembly 22 in the second direction.

[0093] In the embodiments of the present application, the dimension d1 of the first main body portion in the second direction can be understood as the thickness of the first main body portion 23a, and the dimension d2 of the first bent portion in the first direction can be understood as the thickness of the first bent portion 23b. It is positively correlated with the size of the overcurrent cross-section of the current.

[0094] In the embodiments of the present application, the first main body portion 23a and the first bending portion 23b which are "arranged at an angle" may refer to the angle formed to make the first main body portion 23a and the first bending portion 23b conform to the edge shape of the electrode assembly 22. Similarly, the second main body portion 24a and the second bending portion 24b which are "arranged at an angle" may refer to the angle formed to make the second main body portion 24a and the second bending portion 24b conform to the edge shape of the electrode assembly 22. This angle can be an acute angle, a right angle or an obtuse angle.

[0095] In the embodiments 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.

[0096] Exemplarily, the first annular welding portion formed between the first welding hole 23b3 and the positive electrode column 21c, and the second annular welding portion formed between the second welding hole 24b3 and the negative electrode column 21d can be formed by butt welding.

[0097] In the embodiments of the present application, the shape of the top cover 21b can be adapted to the shape of the housing 21a to cooperate with the housing 21a. Optionally, the top cover 21b can be made of a material with certain hardness and strength (such as aluminum alloy). In this way, the top cover 21b is not easily deformed when being squeezed or collided, enabling the battery cell 20 to have higher structural strength. The positive electrode column and the negative electrode column are respectively electrically connected to the electrode assembly 22 through the positive electrode connector 23 and the negative electrode connector 24 for outputting or inputting the electric energy of the battery cell 20. In some embodiments, a pressure relief mechanism for relieving the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value can also be provided on the top cover 21b. The housing 21a is a component for cooperating with the top cover 21b to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 22, the electrolyte and other components.

[0098] The electrode assembly 22 is a component in the battery cell where an electrochemical reaction occurs. The housing 21a can contain one or more electrode assemblies 22. The positive electrode tab 22c and the negative electrode tab 22d are respectively constituted by the parts of the positive electrode plate 22a and the negative electrode plate 22b that do not have active substances. A separator is usually arranged between the positive electrode plate 22a and the negative electrode plate 22b. During the charge and discharge process of the battery, the positive electrode active substance and the negative electrode active substance react with the electrolyte, and the positive electrode plate 22a is connected to the positive electrode column 21c through the positive electrode connector 23, and the negative electrode plate 22b is connected to the negative electrode column 21d through the negative electrode connector 24 to form a current loop.

[0099] It can be understood that in the embodiments 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, and this gap only needs to satisfy that the electrode assembly 22 can be inserted into and taken out along the inner wall of the battery cell 20.

[0100] The size H1 (i.e., height) of the battery cell in the first direction can be 80mm, 90mm, 100mm, 110mm, 120mm, 130mm or a numerical range composed of any two of the above values. The size W1 (i.e., width) of the battery cell in the second direction can be 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, 260mm, 270mm, 280mm, 290mm, 300mm, 310mm, 320mm, 330mm, 340mm, 350mm or a numerical range composed of any two of the above values. 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 composed of any two of the above values.

[0101] The size d1 (i.e., thickness) of the first main body portion in the second direction can be 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm or a numerical range composed of any two of the above values. The size d2 (i.e., thickness) of the first bent portion in the first direction can be 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm or a numerical range composed of any two of the above values.

[0102] The dimension d3 (i.e., the thickness) of the second main body portion in the second 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 composed of any two of the above values. The dimension d4 (i.e., the thickness) of the second bending portion 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 composed of any two of the above values.

[0103] In the technical solution of the present application, the battery cell 20 adopts the above appropriate dimensions in the first direction and the second direction, and is combined with the positive electrode tab 22c and the negative electrode tab 22d arranged on both sides of the electrode assembly 22 in the second direction, that is, the tabs are led out from the short sides on different sides, which reasonably and effectively improves the space utilization rate of the battery cell, thereby facilitating the acquisition of a high energy density. Through the cooperation of the above dimensions of the first main body portion 23a of the positive electrode connecting member 23, the first bending portion 23b, the second main body portion 24a of the negative electrode connecting member 24, and the second bending portion 24b, it is beneficial to improve the current-carrying capacity, thereby improving the reliability of stable passage of high current in the fast charging scenario. And the first annular welding portion and the second annular welding portion formed in the technical solution of the present application are beneficial to improving the stability and firmness of welding, and are beneficial to improving the reliability of stable passage of high current.

[0104] In some embodiments, referring to Figure 5 , the sum of the dimension d5 of the first main body portion in the first direction and the dimension d6 of the first bending portion in the second direction is 50 mm to 90 mm. The sum of the dimension d5 of the first main body portion in the first direction and the dimension d6 of the first bending 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 composed of any two of the above values. Thus, it is beneficial to optimize the electron transmission path, thereby reducing the internal resistance of the positive electrode connecting member 23.

[0105] In some embodiments, referring to Figure 6, the sum of the dimension d7 of the second main body part in the first direction and the dimension d8 of the second bending part in the second direction is 50 mm to 90 mm. The sum of the dimension d7 of the second main body part in the first direction and the dimension d8 of the second bending part 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 any numerical interval composed of any two of the above numerical ranges. Thus, it is beneficial to optimize the electron transmission path, thereby reducing the internal resistance of the negative electrode connecting member 24.

[0106] In some embodiments, the dimension d5 of the first main body part in the first direction is 25% to 50% of the dimension H1 of the battery cell in the first direction. Thus, it is beneficial to optimize the electron transmission path, thereby reducing the internal resistance of the positive electrode connecting member 23. The dimension d5 of the first main body part 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 any numerical interval composed of any two of the above numerical ranges.

[0107] In some embodiments, the dimension d7 of the second main body part in the first direction is 25% to 50% of the dimension H1 of the battery cell in the first direction. Thus, it is beneficial to optimize the electron transmission path, thereby reducing the internal resistance of the negative electrode connecting member 24. The dimension d7 of the second main body part 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 battery cell in the first direction or any numerical interval composed of any two of the above numerical ranges.

[0108] In some embodiments, refer to Figure 7, the dimension d9 of the first main body portion in the third direction is less 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 portion in the third direction and the dimension T1 of the battery cell in the third direction is 5 mm to 15 mm. As an example, in the embodiments of the present application, the dimension d9 of the first main body portion in the third direction is the same as the dimension of the first bending portion in the third direction. Thus, it is beneficial to the effective contact between the positive electrode connecting member 23 and the positive electrode tab. The absolute value of the above difference can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm or a numerical range composed of any two of the above numerical values.

[0109] In some embodiments, referring to Figure 8 , the dimension d10 of the second main body portion in the third direction is less 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 portion in the third direction and the dimension T1 of the battery cell in the third direction is 5 mm to 15 mm. As an example, in the embodiments of the present application, the dimension d9 of the first main body portion in the third direction is the same as the dimension of the first bending portion in the third direction. Thus, it is beneficial to the effective contact between the negative electrode connecting member 24 and the positive electrode tab. The absolute value of the above difference can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm or a numerical range composed of any two of the above numerical values.

[0110] In some embodiments, referring to Figure 9 , at least one positive electrode tab 22c is provided on each positive electrode plate 22a, and each positive electrode tab 22c is provided at the first side end of the positive electrode plate 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 plate 22a in the first direction. Thus, it is beneficial to increase the contact area between the positive electrode tab and the positive electrode plate 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 plate 22a in the first direction or a numerical range composed of any two of the above numerical values.

[0111] In the embodiments of the present application, as an example, the shape of the positive electrode tab 22c can be square. At this time, the dimension d11 of the positive electrode tab in the first direction is the same. It can be understood that the shape of the positive electrode tab 22c can also be other existing feasible shapes, such as trapezoidal or other irregular shapes. At this time, the above-mentioned dimension d11 of the positive electrode tab in the first direction can refer to the dimension at the connection between the positive electrode plate 22a and the positive electrode tab 22c.

[0112] In some embodiments, referring to Figure 10 , at least one negative electrode tab 22d is provided on each negative electrode plate 22b, and each negative electrode tab 22d is provided at the second side end of the negative electrode plate 22b in the second direction. The size d12 of the negative electrode tab in the first direction is 90% to 100% of the size of the negative electrode plate 22b in the first direction. Thus, it is beneficial to increase the contact area between the negative electrode tab 22d and the positive electrode plate 22a, thereby reducing the resistance when current passes through. The size 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 numerical interval composed of any two numerical ranges of the size of the negative electrode plate 22b in the first direction.

[0113] In an embodiment of the present application, as an example, the shape of the negative electrode tab 22d can be square. At this time, the sizes d12 of the negative electrode tab in the first direction are the same. It can be understood that the shape of the negative electrode tab 22d can also be other existing feasible shapes, such as trapezoidal or other irregular shapes. At this time, the above-mentioned size d12 of the negative electrode tab in the first direction can refer to the size at the connection between the negative electrode plate 22b and the negative electrode tab 22d.

[0114] In some embodiments, continue to refer to Figure 5 , the first bending portion 23b includes a first welding section 23b1 and a first connecting section 23b2. A first welding hole 23b3 is provided on the first welding section 23b1, and the first connecting section 23b2 connects the first welding section 23b1 and the first main body portion 23a; wherein, the size d13 of the first connecting section in the first direction is greater than the size d14 of the first welding section in the first direction. The first bending portion presents a stepped shape. The first welding section 23b1 is relatively thin, which is beneficial to improving the reliability of welding. The first connecting section 23b2 is relatively thick, which is beneficial to ensuring the current-carrying capacity.

[0115] In some embodiments, the size d13 of the first connecting section in the first direction is 1.5 to 3.0 mm. Thus, it is beneficial to improve the reliability of high-current stable passing in a fast charging scenario. The size d15 of the second connecting section 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 any numerical interval composed of any two numerical ranges above.

[0116] In some embodiments, the dimension d14 of the first welding section in the first direction is 1.0 - 2.5 mm. Thus, it is beneficial to balance the stability of welding while improving the reliability of high-current stable passing. 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 any numerical interval composed of any two of the above numerical ranges.

[0117] In some embodiments, referring to Figure 4 and Figure 5 , on the side of the first bending portion 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 further includes an insulating sheet 25 at least partially covering the surface of the first welding section 23b1, and the insulating sheet 25 is disposed between the first welding section 23b1 and the electrode assembly 22. It can be understood that the above-mentioned recessed part is disposed on the side facing away from the top cover 21b, so that the insulating sheet 25 can be disposed between the first welding section 23b1 and the electrode assembly 22. The setting of the insulating sheet 25 can prevent welding slag from falling into the gap between the electrode assemblies 22 when welding the positive electrode post 21c and the positive electrode connecting member 23.

[0118] In some embodiments, referring to Figure 6 , the second bending portion 24b of the negative electrode connecting member 24 includes a second welding section 24b1 and a second connecting section 24b2. A second welding hole 24b3 is provided on the second welding section 24b1, and the second connecting section 24b2 connects the second welding section 24b1 and the second main body portion 24a. Among them, the dimension d15 of the second connecting section in the first direction is greater than the dimension d16 of the second welding section in the first direction. Similarly, the second bending portion is in a stepped shape. The second welding section 24b1 is relatively thin, which is beneficial to improving the welding reliability, and the second connecting section 24b2 is relatively thick, which is beneficial to ensuring the current-carrying capacity.

[0119] In some embodiments, the dimension d15 of the second connecting section in the first direction is 1.2 - 2.5 mm. Thus, it is beneficial to improve the reliability of high-current stable passing in a fast charging scenario. The dimension d15 of the second connecting section 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 any numerical interval composed of any two of the above numerical ranges.

[0120] In some embodiments, the dimension d16 of the second welding section in the first direction is 1.0 - 2.0 mm. Thus, it is beneficial to balance the stability of good welding while enhancing the reliability of high current passing stably. 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 numerical range composed of any two of the above values.

[0121] In some embodiments, referring to Figure 4 and Figure 6 , on the side of the second bending portion 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 further includes an insulating sheet 25 at least partially covering the surface of the second welding section 24b1, and the insulating sheet 25 is disposed between the second welding section 24b1 and the electrode assembly 22. It can be understood that the above-mentioned recessed part is disposed on the side facing away from the top cover 21b, which enables the insulating sheet 25 to be disposed between the second welding section 24b1 and the electrode assembly 22. The setting of the insulating sheet 25 can prevent welding slag from falling into the gap between the electrode assemblies 22 when welding the negative electrode post 21d and the negative electrode connecting member 24.

[0122] In some embodiments, the diameter of the positive electrode post 21c is 9 - 22 mm. Thus, it is beneficial to enhance the reliability of high current passing stably in a fast charging scenario. The diameter of the positive electrode post 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 composed of any two of the above values.

[0123] In some embodiments, the diameter of the negative electrode post 21d is 9 - 22 mm. Thus, it is beneficial to enhance the reliability of high current passing stably in a fast charging scenario. The diameter of the negative electrode post 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 numerical range composed of any two of the above values.

[0124] In some embodiments, referring to Figure 11, the top cover 21b includes a first edge and a second edge in the second direction, the distance d17 between the central axis of the positive electrode post and the first edge is 15 - 35 mm; the distance d18 between the central axis of the negative electrode post and the second edge is 15 - 35 mm. The positions of the positive electrode post 21c and the negative electrode post 21d are arranged to make the battery structure more reasonable and optimize the electron transmission path. The distance d17 between the central axis of the positive electrode post and the first edge can be 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm or any numerical interval composed of any two of the above numerical ranges. The distance d18 between the central axis of the negative electrode post and the second edge can be 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm or any numerical interval composed of any two of the above numerical ranges.

[0125] In some embodiments, the positive electrode tab 22c at least partially covers the first main body portion. Due to the existence of multiple layers of positive electrode tabs, the positive electrode tab 22c can be bent and partially or completely cover the first main body portion 23a. Thus, it is beneficial to increase the contact area between the positive electrode tab 22c and the positive electrode connector 23 and reduce the internal resistance. In some embodiments, the negative electrode tab 22d at least partially covers the second main body portion. Similarly, due to the existence of multiple layers of negative electrode tabs 22d, the negative electrode tab 22d can be bent and partially or completely cover the second main body portion 24a. Thus, it is beneficial to increase the contact area between the negative electrode tab 22d and the negative electrode connector 24 and reduce the internal resistance.

[0126] In some embodiments, a heat insulation film layer is provided between the negative electrode tab 22d and the negative electrode connector 24. Thus, it is beneficial to isolate heat and improve the reliability of the battery.

[0127] In some embodiments, a heat insulation film layer is provided between the positive electrode tab 22c and the positive electrode connector 23. Thus, it is beneficial to isolate heat and improve the reliability of the battery.

[0128] In some embodiments, a heat insulation film layer is provided between the electrode assembly 22 and the housing 21a. Thus, it is beneficial to isolate heat and improve the reliability of the battery.

[0129] In some embodiments, a heat insulation film layer is provided between the electrode assembly 22 and the top cover 21b. Thus, it is beneficial to isolate heat and improve the reliability of the battery.

[0130] In some embodiments, the material of the heat insulation film layer includes at least one of polyimide and polyethylene terephthalate. The heat insulation film layer made of the above materials is beneficial to isolate heat and improve the reliability of the battery.

[0131] In some embodiments, the thickness of the heat insulation film layer is 10-100 μm. At this appropriate thickness, it is beneficial to make reasonable use of the battery space, isolate heat, and improve the reliability of the battery. The thickness of the heat 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 any numerical interval composed of any two of the above numerical ranges.

[0132] In some embodiments, the size T1 of the battery cell in the third direction is 30-50 mm. At this appropriate thickness, it is beneficial to make reasonable use of the battery space and give full play to the high energy density of the battery. The size 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 numerical interval composed of any two of the above numerical ranges.

[0133] 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 disposed on at least one surface of the negative electrode current collector, and the second film layer is disposed 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 average longest diameter particle size of the second negative electrode active material is smaller than the average longest diameter particle size of the first negative electrode active material.

[0134] In this article, the "average longest diameter particle size" means that the electrode plate is ion-polished and cut along the thickness direction of the electrode plate to expose the cross-section of the film layer. The cross-section of the film layer can be tested by a scanning electron microscope (SEM). At a magnification of 1000 times in the SEM scenario, more than 50 particles are randomly selected, and the length of the longest straight line passing through the center point of each particle and extending to the outer periphery of the particle is measured, and then the average value of the longest straight line lengths of these particles is taken.

[0135] Thus, the average longest diameter particle size of the active material used in the second film layer is relatively smaller, and the ion transport distance of ions in the second film layer is relatively shorter, which is beneficial to further improve the fast charging performance of the battery cell. While the average longest diameter particle size of the active material used in the first film layer is relatively larger, and the compaction density of the first film layer is relatively higher, which is beneficial to taking into account good energy density.

[0136] In some embodiments, the average longest diameter particle size of the first negative electrode active material is 7 to 18 μm. Thus, it is beneficial to exert the effect that the compaction density of the first film layer is relatively higher. The average longest diameter 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 numerical range composed of any two of the above values.

[0137] In some embodiments, the first negative electrode active material includes at least one of artificial graphite and natural graphite.

[0138] In some embodiments, the first negative electrode active material includes a negative electrode active material with a secondary particle morphology.

[0139] In this application, a particle with a primary particle morphology refers to a primary particle. A primary particle is the smallest unit of a particle within a certain observation range. There may be any form of defects inside the primary particle, but it is impossible to define smaller particles within the primary particle. Primary particles may aggregate under physical actions such as van der Waals forces, but this aggregation is easily depolymerized under external forces such as ultrasonic waves, stirring, and rolling, so that the main composition form of the active material in the film layer is still primary particles.

[0140] In this application, a particle with a secondary particle morphology refers to a secondary particle. A secondary particle is formed by the aggregation of primary particles and is not easily dispersed under external forces such as ultrasonic waves. However, after cutting the cross-section of the secondary particle, it can be seen that the secondary particle is formed by the aggregation of numerous primary particles.

[0141] 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 composed of any two of the above values.

[0142] In this application, the volume distribution particle size Dv50 of a material represents the particle size corresponding to when the cumulative volume distribution percentage of the material reaches 50%, and can be measured by known instruments and methods in the art. For example, it can be conveniently measured by referring to GB / T19077-2016 Laser Diffraction Method for Particle Size Distribution and using a laser particle size analyzer. The test instrument can be the Mastersizer3000 type laser particle size analyzer of Malvern Instruments Limited, UK.

[0143] In some embodiments, the first negative electrode active material includes a carbon coating layer with a thickness of 100 to 500 nm. The carbon coating layer is beneficial to improving 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 any numerical range composed of any two of the above values.

[0144] The thickness of the coating layer can be characterized by transmission electron microscopy (TEM) testing. Observe the negative electrode active material through transmission electron microscopy. According to the difference in lattice fringes, the coating layer coated on the surface of the negative electrode active material can be clearly observed. Randomly select 5 positions in the coating layer for testing, and calculate the average value as the average thickness of the coating layer.

[0145] In some embodiments, the graphitization degree of the first negative electrode active material is 90 to 94%. A high graphitization degree of the material indicates a small graphite layer spacing, less lattice rotation, less disordered stacking of the layers, and an ordered arrangement. The specific capacity of the material is high, which is beneficial to obtaining a battery cell with a high energy density. The graphitization degree of the first negative electrode active material can be 90%, 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94% or any numerical range composed of any two of the above values.

[0146] In this article, the term "graphitization degree" macroscopically characterizes what proportion of the material reaches a complete graphite crystal structure; microscopically, it refers to the degree to which different transitional carbon structures approach an ideal graphite crystal.

[0147] In this application, the graphitization degree of graphite can be tested by instruments and methods known in the art. For example, an X-ray diffractometer (such as Bruker D8 Discover) can be used for testing. The test can refer to JISK 0131-1996 and JB / T4220-2011 to obtain the average layer spacing d002 of the C(002) crystal plane in the crystal structure of the material, and then calculate the graphitization degree according to the formula g=(0.344 - d002) / (0.344 - 0.3354)×100%. In the above formula, d002 is the average layer spacing of the C(002) crystal plane in the crystal structure of the material expressed in nanometers (nm).

[0148] In some embodiments, the first negative electrode active material includes a silicon material, and the mass ratio of silicon element in the silicon material in the first negative electrode active material is 0.5% to 10%. The addition of the silicon material is beneficial to further improving the energy density of the battery cell. The mass ratio of silicon element 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 any numerical range composed of any two of the above values.

[0149] In this application, the content of silicon element can be tested by instruments and methods known in the art. For example, the negative electrode active material can be placed in an appropriate digestion solvent, concentrated nitric acid solvent, and digested by plate digestion method. Finally, it is dissolved and extracted with hydrochloric acid, and then the obtained solution is fixed to an appropriate volume and quantitatively tested by inductively coupled plasma optical emission spectrometer ICP=OES.

[0150] In some embodiments, the average longest diameter particle size of the second negative electrode active material is 6 to 10 μm. Thus, it is beneficial to play the role that the ion transport distance in the second film layer is relatively shorter. The average longest diameter particle size of the second negative electrode active material can be 6 μm, 7 μm, 8 μm, 9 μm, 10 μm or any numerical range composed of any two of the above values.

[0151] In some embodiments, the second negative electrode active material includes at least one of artificial graphite and natural graphite.

[0152] In some embodiments, the second negative electrode active material includes a negative electrode active material with a secondary particle morphology.

[0153] 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 any numerical range composed of any two of the above values.

[0154] In some embodiments, the second negative electrode active material includes a carbon coating layer, and the thickness of the carbon coating layer is 100 to 500 nm. The carbon coating layer is beneficial to improving 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 any numerical range composed of any two of the above values.

[0155] In some embodiments, the graphitization degree of the second negative electrode active material is 90% to 94%. A high graphitization degree of the material indicates a small graphite layer spacing, a smaller lattice rotation, less disordered stacking of the layers, an ordered arrangement, a high specific capacity of the material, and is conducive to obtaining a battery cell with a high energy density. The graphitization degree of the second negative electrode active material can be 90%, 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94% or any numerical range composed of any two of the above values.

[0156] In some embodiments, the second negative electrode active material includes a silicon material, and the mass ratio of silicon element in the silicon material in the second negative electrode active material is 0.5% to 10%. The addition of the silicon material is conducive to further improving the energy density of the battery cell. The mass ratio of silicon element in the silicon material in the second 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 any numerical range composed of any two of the above values.

[0157] In some embodiments, the thickness of the first film layer is 30% to 70% of the total thickness of the negative electrode film layer. Thus, it is conducive to exerting the role of the first film layer in taking into account 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 any numerical range composed of any two of the above values.

[0158] In some embodiments, the thickness of the second film layer is 30% to 70% of the total thickness of the negative electrode film layer. Thus, it is conducive to further improving 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 any numerical range composed of any two of the above values.

[0159] The thicknesses of the first film layer and the second film layer can be characterized by transmission electron microscopy (TEM) testing. Observe the cross-section of the negative electrode sheet through transmission electron microscopy, and observe the thicknesses of the first film layer and the second film layer according to the difference in the average longest diameter particle size of the active materials in the first film layer and the second film layer. Take the average value after observing, for example, 5 times.

[0160] In some embodiments, under the condition that the state of charge (SOC) of the battery cell is 0%, the tap density of the single-sided negative electrode film layer of the negative electrode sheet is 1.3 to 1.52 g / cc. Thus, a suitable tap density is beneficial to further adjust the porosity of the negative electrode sheet within a suitable range. Under the condition that the state of charge (SOC) of the battery cell is 0%, the tap density of the single-sided negative electrode film layer of the negative electrode sheet can be 1.3 g / cc, 1.31 g / cc, 1.32 g / cc, 1.33 g / cc, 1.34 g / cc, 1.35 g / cc, 1.36 g / cc, 1.37 g / cc, 1.38 g / cc, 1.39 g / cc, 1.4 g / cc, 1.41 g / cc, 1.42 g / cc, 1.43 g / cc, 1.44 g / cc, 1.45 g / cc, 1.46 g / cc, 1.47 g / cc, 1.48 g / cc, 1.49 g / cc, 1.5 g / cc, 1.51 g / cc, 1.52 g / cc or any numerical range composed of any two of the above values.

[0161] In the present application, the tap density of the electrode sheet has the meaning well-known in the art and can be measured by methods known in the art. Under the condition that the state of charge (SOC) of the battery cell is 0%, the electrode sheet is removed from the lithium-ion battery, and a certain area of the electrode sheet is taken. The mass and thickness of the electrode sheet and the current collector after removing the film layer are measured respectively. According to the following formula, the tap density of the electrode sheet is calculated. Tap density of the electrode sheet = (mass of the electrode sheet - mass of the current collector) / [(thickness of the electrode sheet - thickness of the current collector) × area of the electrode sheet].

[0162] In some embodiments, the areal density of the single-sided negative electrode film layer of the negative electrode sheet is 0.12 to 0.18 g / 1540.25 mm 2 . Thus, a suitable areal density is beneficial to further adjust the porosity of the negative electrode sheet within a suitable range. The areal density of the single-sided negative electrode film layer of the negative electrode sheet can be 0.12 g / 1540.25 mm 2 , 0.13 g / 1540.25 mm 2 , 0.14 g / 1540.25 mm 2 , 0.15 g / 1540.25 mm 2 , 0.16 g / 1540.25 mm 2 , 0.17 g / 1540.25 mm 2 , 0.18 g / 1540.25 mm 2 or any numerical range composed of any two of the above values.

[0163] In this application, the areal density of the film layer has the meaning well-known in the art and can be tested by methods known in the art. For example, take a single-sided coated and cold-pressed electrode sheet (if it is a double-sided coated electrode sheet, the film layer on one side can be wiped off), punch it into small round pieces with an area of S1, weigh it, and record it as M1. Then wipe off the film layer of the electrode sheet after weighing above, weigh the weight of the current collector, and record it as M0. The areal density of the single-sided film layer = (M1 - M0) / S1. To ensure the accuracy of the test results, multiple groups (for example, 10 groups) of samples to be tested can be tested, and the average value can be calculated as the test result.

[0164] In some embodiments, under the condition that the state of charge SOC of the battery cell is 0%, the tap density of the single-sided positive electrode film layer of the positive electrode sheet is 2.3 - 2.6 g / cc. Thus, a suitable tap density is beneficial to further adjust 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 tap density of the single-sided positive electrode film layer of the positive electrode sheet can be 2.3 g / cc, 2.31 g / cc, 2.32 g / cc, 2.33 g / cc, 2.34 g / cc, 2.35 g / cc, 2.36 g / cc, 2.37 g / cc, 2.38 g / cc, 2.39 g / cc, 2.4 g / cc, 2.41 g / cc, 2.42 g / cc, 2.43 g / cc, 2.44 g / cc, 2.45 g / cc, 2.46 g / cc, 2.47 g / cc, 2.48 g / cc, 2.49 g / cc, 2.5 g / cc, 2.51 g / cc, 2.52 g / cc, 2.53 g / cc, 2.54 g / cc, 2.55 g / cc, 2.56 g / cc, 2.57 g / cc, 2.58 g / cc, 2.59 g / cc, 2.6 g / cc or any numerical range composed of any two of the above values.

[0165] In some embodiments, the areal density of the single-sided positive electrode film layer of the positive electrode sheet is 0.25 - 0.33 g / 1540.25mm 2 . Thus, a suitable areal density is beneficial to further adjust the porosity of the positive electrode sheet within a suitable range. The areal density of the single-sided positive electrode film layer of the positive electrode sheet can be 0.25 g / 1540.25mm 2 , 0.26 g / 1540.25mm 2 , 0.27 g / 1540.25mm 2 , 0.28 g / 1540.25mm 2 , 0.29 g / 1540.25mm 2 , 0.3 g / 1540.25mm 2 , 0.31 g / 1540.25mm 2, 0.32 g / 1540.25 mm 2 , 0.33 g / 1540.25 mm 2 or a numerical range composed of any two of the above values.

[0166] In some embodiments, the lithium-containing phosphate includes lithium iron phosphate, and the lithium iron phosphate includes metal elements, and the metal elements include at least one of aluminum, titanium, and vanadium. Adding the above metal elements to lithium iron phosphate is beneficial to improving the tap density of the positive electrode active material.

[0167] In this application, the contents of aluminum, titanium, and vanadium in the lithium-containing phosphate can be tested by instruments and methods known in the art. For example, the lithium-containing phosphate can be placed in a proper digestion solvent, concentrated nitric acid solvent, and digested by the plate digestion method. Finally, it is dissolved and extracted with hydrochloric acid, and then the obtained solution is fixed to an appropriate volume and quantitatively tested by an inductively coupled plasma optical emission spectrometer ICP-OES.

[0168] In some embodiments, the metal element includes aluminum, and the mass ratio of aluminum in the lithium-containing phosphate is 0.02% - 0.25%. Thus, it is beneficial to play the role of aluminum doping in improving the tap density of the positive electrode active material and further improving the cycle performance of the battery cell. The mass ratio 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 composed of any two of the above values.

[0169] In some embodiments, the metal element includes titanium, and the mass ratio of the titanium in the lithium-containing phosphate is 0.15% - 0.35%. Thus, it is beneficial to play the role of titanium doping in improving the tap density of the positive electrode active material and further increasing the battery capacity. The mass ratio of the 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 composed of any two of the above values.

[0170] 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%. As a result, it is beneficial to play the role of vanadium doping in improving the compaction density of the positive electrode active material and further improving 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 interval consisting of any two of the above values.

[0171] In some embodiments, the lithium-containing phosphate includes a lithium-containing phosphate in the form of primary particles and a 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.

[0172] In some embodiments, the longest diameter average particle size of the lithium-containing phosphate in the primary particle morphology is 300-800nm. This is conducive to shortening the ion transmission distance and thus improving the fast charging performance. The longest diameter average particle size of the lithium-containing phosphate in the primary particle morphology can be 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm ​​or a numerical interval consisting of any two of the above values.

[0173] In some embodiments, the longest diameter average particle size of the lithium-containing phosphate in the secondary particle morphology is 8μm to 15μm. The secondary particles are usually composed of lithium-containing phosphates with smaller primary particles, which is beneficial to shorten the ion transmission distance. The longest diameter 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.

[0174] In some embodiments, the lithium-containing phosphate in the secondary particle morphology is 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.

[0175] 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.

[0176] An embodiment of the present application also provides a battery device, including the battery cell provided by the present application.

[0177] As the electrical device, a battery cell, a battery module or a battery pack can be selected according to its usage requirements.

[0178] 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 a battery module may be used.

[0179] As another example, the device may be a mobile phone, a tablet computer, a notebook computer, etc. The device is usually required to be light and thin, and a battery cell may be used as a power source.

[0180] An embodiment of the present application also provides an electrical device, including the battery device provided in the present application.

[0181] Example Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0182] Example 1 1. Preparation of positive electrode sheet The positive electrode plate 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.

[0183] The positive electrode film layer includes a film layer formed by uniformly coating a positive electrode slurry (the solvent is N-methylpyrrolidone NMP) on the surface of a positive electrode current collector, drying, and cold pressing. 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.

[0184] 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, wherein the mass proportion of Al, V, and Ti in the lithium iron phosphate particles is 0.15% each.

[0185] The lithium iron phosphate particles include primary particles and secondary particles formed by agglomeration of the primary particles. The secondary particles are spherical and quasi-spherical. The longest average particle size of the primary particles is 600nm, and the longest average particle size of the secondary particles is 10μm. The volume distribution particle size Dv50 of the lithium iron phosphate particles is 7μm.

[0186] The surface density of the single-sided positive electrode film is 0.28g / 1540.25mm 2 .

[0187] 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.

[0188] The porosity of the positive electrode sheet is 25%.

[0189] 2. Preparation of negative electrode sheet 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 a copper foil.

[0190] 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, and then drying and cold pressing.

[0191] The first film layer is arranged on the surface of the negative electrode current collector, and includes the first negative electrode active material, the conductive agent acetylene black, the negative electrode binder styrene butadiene rubber, and the thickener sodium carboxymethyl cellulose in a mass ratio of 96.5:0.5:2:1. The negative electrode active material includes graphite and silicon oxide, and the mass proportion of silicon in the first negative electrode active material is 5%. The graphite includes artificial graphite and a carbon coating layer, and the carbon coating layer is coated on the surface of the artificial graphite. The thickness of the carbon coating layer is 200nm, and the graphitization degree of the graphite is 92%. The longest average particle size of the graphite is 12μm.

[0192] The second film layer is arranged on the surface of the negative electrode current collector, which includes the negative electrode active material, the conductive agent acetylene black, the negative electrode binder styrene butadiene rubber, and the thickener sodium carboxymethyl cellulose in a mass ratio of 96.5:0.5:2:1. The negative electrode active material includes graphite and silicon oxide, and the mass proportion of silicon in the first negative electrode active material is 5%. The graphite includes artificial graphite and a carbon coating layer, and the carbon coating layer is coated on the surface of the artificial graphite. The thickness of the carbon coating layer is 200nm, and the graphitization degree of the graphite is 92%. The longest average particle size of the graphite is 9μm.

[0193] 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.

[0194] The surface density of the single-sided negative electrode film is 0.13g / 1540.25mm 2 .

[0195] 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.

[0196] The porosity of the negative electrode sheet is 28%.

[0197] 3. Isolation film The isolation film is a 7 μm polyethylene film layer.

[0198] 4. Preparation of electrolyte 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%.

[0199] 5. Preparation of battery cells The above-mentioned positive electrode sheet, isolation membrane, and negative electrode sheet are stacked in order, so that the isolation membrane is located between the positive electrode sheet and the negative electrode sheet to play an isolating role, to obtain a stacked 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 of the electrode assembly in the second direction.

[0200] 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, and 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 a battery cell is obtained through vacuum packaging, standing, forming, shaping and other processes.

[0201] 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.

[0202] The positive electrode connecting member includes a first main body 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 post to pass through and connect, and a first annular welding portion is formed between the first welding hole and the positive electrode post. The first main body portion is electrically connected to the positive electrode tab; the dimension d1 of the first main body 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; Wherein, the dimension of the first main body portion in the first direction is 25 mm, and the sum of the dimension of the first main body portion 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 hole is provided on the first welding section, and 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.

[0203] The negative electrode connecting member includes a second main body portion and a second bent portion arranged at an angle. The second bent portion is provided with a second welding hole for the negative electrode post to pass through and connect, and a second annular welding portion is formed between the second welding hole and the negative electrode post; the second main body portion is electrically connected to the negative electrode tab; the dimension d3 of the second main body portion in the second direction is 2 mm, and the dimension d4 of the second bent portion in the first direction is 2 mm.

[0204] Wherein, the dimension of the second main body portion in the first direction is 25 mm, and the sum of the dimension of the second main body portion 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. The second welding hole is provided on the second welding section, and the dimension of the second connecting section in the first direction is 2 mm; the dimension of the second welding section in the first direction is 1.0 mm.

[0205] The diameter of the positive electrode post is 15 mm, and the diameter of the negative electrode post is 15 mm.

[0206] Examples 2 - 7 and Comparative Examples 1 - 2 were used to prepare the battery in a similar manner to Example 1. The differences can be seen in Tables 1 and 3.

[0207] Comparative Example 3 This comparative example was used to prepare the battery in a similar manner to Example 1. The difference from Example 1 is that: The positive electrode plate, the separator, and the negative electrode plate were stacked in sequence, with the separator placed between the positive electrode plate and the negative electrode plate to play an isolation role, obtaining a stacked electrode assembly. Among them, multiple positive electrode plates and multiple negative electrode plates were stacked in the third direction. The positive electrode tab and the negative electrode tab were both located at the same end (top end) in the first direction of the electrode assembly, and the positive electrode tab and the negative electrode tab were spaced apart.

[0208] Place the electrode assembly in the housing, which includes a housing body and a top cover covering one end port of the housing body in the first direction. A positive terminal and a negative terminal are provided on the top cover along the second direction. The positive electrode tab and the negative electrode tab are disposed close to the top cover, with the positive electrode tab close to the positive terminal and the negative electrode tab close to the negative terminal. After baking, inject the electrolyte, and through processes such as vacuum packaging, standing, formation, and shaping, a battery cell is obtained.

[0209] In this embodiment, the size H1 of the battery cell in the first direction is 100 mm; the size W1 of the battery cell in the second direction is 300 mm; the size T1 of the battery cell in the third direction is 50 mm.

[0210] The positive connection member is a solid rectangular sheet, connected between the positive electrode tab and the positive terminal. The size of the positive connection member in the first direction is 1.2 mm.

[0211] The negative connection member is a solid rectangular sheet, connected between the negative electrode tab and the negative terminal. The size of the negative connection member in the first direction is 0.8 mm.

[0212] The diameter of the positive terminal is 15 mm, and the diameter of the negative terminal is 15 mm.

[0213] 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.

[0214] Performance test: (1) Temperature rise difference of the positive terminal: Arrange temperature sensing wires on the terminals of the battery cell to monitor the temperature change of the battery cell during charge and discharge at a 4C rate. At 25°C, for the assembled battery, record the initial temperature T1, then fully charge at a 4C rate, and record the temperature T2. The temperature rise difference of the positive terminal is the difference between T2 and T1.

[0215] (2) Energy density test: At 25°C, for the assembled battery cell, fully charge at a 0.5C rate and fully discharge at a 0.5C rate, and record the actual discharge energy at this time; at 25°C, weigh the battery using an electronic balance; the ratio of the 0.5C actual discharge energy of the battery to the battery weight is the energy density of the battery.

[0216] Table 1

[0217] In Table 1, the size d2 of the first bending portion in the first direction refers to the maximum size of the first bending portion in the first direction, and the size d4 of the second bending portion in the first direction refers to the maximum size of the second bending portion in the first direction. The unit of each size in Table 1 is mm.

[0218] In Comparative Example 1, the thickness of the positive electrode connecting member is relatively smaller, and the temperature rise difference of the positive electrode terminal is too large. In Comparative Example 2, the thickness of the negative electrode connecting member is relatively smaller, and the temperature rise difference of the positive electrode terminal is too large.

[0219] In Embodiments 1-5 of the present application, by adjusting the dimension d1 of the first main body portion in the second direction, the dimension d2 of the first bending portion in the first direction, the dimension d3 of the second main body portion in the second direction, and the dimension d4 of the second bending portion in the first direction within a suitable range, that is, by adjusting the thickness of the positive electrode connecting member and the thickness of the negative electrode connecting member within a suitable range, it is beneficial to reduce the temperature rise of the positive electrode terminal. Thus, it is beneficial to improve the reliability of stable passage of high current in a fast charging scenario.

[0220] As can be seen from Embodiments 1-5, as the thickness of the positive electrode connecting member or the negative electrode connecting member increases, the temperature rise difference of the positive electrode terminal decreases. However, in the embodiments of the present application, considering that if the positive electrode connecting member or the negative electrode connecting member is too thick, it is not conducive or even impossible to weld the positive electrode connecting member to the positive electrode terminal (or the negative electrode connecting member to the negative electrode terminal). Therefore, the dimensions of d1, d2, d3, and d4 should not be too large.

[0221] Table 2

[0222] As can be seen from the energy density data of Embodiment 1 and Comparative Example 3 in Table 2, in Comparative Example 3, the positive electrode tab and the negative electrode tab are both arranged at the top of the electrode assembly. Since it occupies more internal space of the battery cell, the energy density of the battery cell decreases.

[0223] Table 3

[0224] In Table 3, M1 refers to the sum of the dimension of the first main body portion in the first direction and the dimension of the first bending portion in the second direction. M2 refers to the sum of the dimension of the second main body portion in the first direction and the dimension of the second bending portion in the second direction. The unit of each dimension in Table 3 is mm.

[0225] As can be seen from Embodiments 1, 6-7, by adjusting M1, M2, the positive electrode terminal diameter, and the negative electrode terminal diameter within a suitable range, it is beneficial to reduce the temperature rise of the positive electrode terminal. Thus, it is beneficial to improve the reliability of stable passage of high current in a fast charging scenario.

[0226] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples, and embodiments having the same composition in essence as the technical idea and achieving the same effects within the scope of the technical solution of this application are all included in the technical scope of this application. In addition, within the scope of not departing from the gist of this application, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways constructed by combining some of the constituent elements in the embodiments are also included in the scope of this 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 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 a first direction, a positive electrode column and a negative electrode column are arranged on the top cover along a second direction, and the electrode assembly is arranged in the shell; The electrode assembly comprises 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 sheet comprises a lithium-containing phosphate, and the negative electrode active material of the negative electrode sheet comprises graphite; The positive electrode connector includes a first main body 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, and the first main body is electrically connected to the positive electrode tab; 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 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.

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

4. The battery cell according to claim 1, characterized in that: 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: The size of the first main body in the third direction is smaller than the size of the battery cell in the third direction, and the absolute value of the 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: The size of the second main body in the third direction is smaller than the size of the battery cell in the third direction, and the absolute value of the 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, characterized in that: At least one positive electrode tab is disposed on each of the positive electrode plates, and each of the positive electrode tabs is disposed at a first side end of the positive electrode plate 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 plate in the first direction.

9. The battery cell according to claim 1, characterized in that: At least one negative electrode tab is disposed on each of the negative electrode plates, and each of the negative electrode tabs is disposed at a second side end of the negative electrode plate in the second direction, and a size of the negative electrode tab in the first direction is 90% to 100% of a 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 comprises: a first welding section, wherein a first welding hole is provided on the first welding section; and A first connecting section connects the first welding section and the first main body; wherein a size of the first connecting section in the first direction is larger than a size of the first welding section in the first direction.

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

12. The battery cell according to claim 10 or 11, characterized in that: The dimension of the first welding section 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 comprises: A second welding section, wherein a second welding hole is provided on the second welding section; and A second connecting segment connects the second welding segment and the second main body; wherein a size of the second connecting segment in the first direction is larger than a 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 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.

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 insulation film layer is arranged 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 arranged between the positive electrode tab and the positive electrode connector.

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

26. The battery cell according to claim 1, characterized in that: A heat insulation film layer is arranged 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 comprises 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 comprises a first film layer and a second film layer, wherein 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 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 graphite in the first negative electrode active material is 7-18 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 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 graphitization degree of the graphite in the first negative electrode active material is 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 graphite in the second negative electrode active material is 6-10 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 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 graphitization degree of the graphite in the second negative electrode active material is 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 single-sided positive electrode film layer 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 0.25-0.33 g / 1540.25 mm 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 lithium-containing phosphate in the secondary particle morphology is 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 a battery cell as claimed in any one of claims 1 to 59.

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

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