Battery monomer, battery device and electric device

Abstract

The invention provides a battery monomer, a battery device and a power utilization device. In the battery monomer, a positive electrode active material comprises lithium-containing phosphate with an olivine structure; the average particle size Dv50 of the negative electrode active material is 8-15 [mu] m, and the negative electrode active material comprises graphite; the negative electrode current collector comprises a negative electrode current collecting part and at least two negative electrode tabs arranged on the same side of the negative electrode current collecting part, the negative electrode tabs extend out of the negative electrode current collecting part in the first direction, the distance between the center lines of any two adjacent negative electrode tabs ranges from 10 mm to 350 mm, and the center lines are parallel to the first direction.

Description

[0001] This application claims the priority of PCT patent application PCT / CN2024 / 116581 titled "Battery Cell, Battery Device and Electrical Device" filed on September 3, 2024, the entire content of which is incorporated herein by reference. Technical Field

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

[0003] In recent years, batteries have been widely used in energy storage power systems such as hydro, thermal, wind and solar power stations, as well as in multiple fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. With the popularization of battery applications, higher requirements have also been put forward for their energy density, fast charging performance, cycle performance, service life, safety performance, etc. Summary of the Invention

[0004] The purpose of this application is to provide a novel battery cell, which has excellent fast charging performance and can also take into account having a relatively high energy density, good cycle performance and low DC internal resistance.

[0005] To achieve the above purpose, a first aspect of this application provides a battery cell, which includes a positive electrode tab, a negative electrode tab and a separator located between the positive electrode tab and the negative electrode tab. The positive electrode tab includes a positive current collector and a positive electrode film layer provided on at least one surface of the positive current collector. The positive electrode film layer includes a positive active material, and the positive active material includes a lithium-containing phosphate with an olivine structure. The negative electrode tab includes a negative current collector and a negative electrode film layer provided on at least one surface of the negative current collector. The negative electrode film layer includes a negative active material, and the average particle size Dv50 of the negative active material is 8 μm to 15 μm. The negative active material includes graphite. The negative current collector includes a negative current collecting portion and at least two negative electrode tabs provided on the same side of the negative current collecting portion. The negative electrode tabs extend from the negative current collecting portion along a first direction, wherein the distance between the center lines of two adjacent negative electrode tabs is 10 mm to 350 mm, and the center line is parallel to the first direction.

[0006] By using negative electrode active materials with small particle sizes, the present application improves the transmission path of lithium ions inside the negative electrode active materials during charging, which is beneficial to improving the fast charging ability of battery cells. However, when the fast charging ability of a battery cell is improved, the corresponding charging current it can withstand also increases. At this time, if the tab structure of the negative electrode is not reasonably arranged, it will cause heat accumulation inside the battery cell during fast charging, resulting in a high internal temperature of the battery, triggering adverse reactions such as gas generation in the electrolyte and an increase in the impedance of the solid electrolyte interface (SEI) membrane of the negative electrode, thereby increasing the internal resistance of the battery and affecting the performance of the battery cell. By adopting a negative electrode tab arrangement within a reasonable distance range, the present application effectively reduces the heat accumulation inside the battery cell when the fast charging ability is improved, reduces the internal temperature rise, and suppresses the increase in the direct current internal resistance (DCR) of the battery cell. In any embodiment, the positive electrode current collector includes a positive electrode current collecting portion and at least two positive electrode tabs disposed on the same side of the positive electrode current collecting portion. The positive electrode tabs extend from the positive electrode current collecting portion along a first direction. Among them, the distance between the centerlines of two adjacent positive electrode tabs is 10 mm to 350 mm, and the centerline is parallel to the first direction.

[0007] In any embodiment, the distance between the centerlines of two adjacent negative electrode tabs is 20 mm to 330 mm.

[0008] In any embodiment, the distance between the centerlines of two adjacent positive electrode tabs is 20 mm to 330 mm.

[0009] In the battery cell provided by the present application, when the positive and negative electrode current collectors respectively include at least two tabs having the above structural features, it can further improve the direct current internal resistance of the battery cell, thereby further reducing the heat generation of the battery and enabling the battery to have better safety performance.

[0010] In any embodiment, the average particle size Dv50 of the negative electrode active material is 9.5 μm to 11.5 μm.

[0011] When the negative electrode active material (such as graphite) has a particle size within the above range, it can further improve the fast charging performance and direct current internal resistance of the battery, and at the same time enable the battery to have better cycle performance.

[0012] In any embodiment, the battery cell includes an electrolyte, the electrolyte includes an organic solvent, and the organic solvent includes a carboxylic acid ester solvent and a carbonate solvent.

[0013] In the battery cell provided by the present application, when the above type of organic solvent is used in the electrolyte, the kinetic performance of the battery can be further improved.

[0014] In any embodiment, the organic solvent includes a linear carboxylic acid ester, and the mass percentage of the linear carboxylic acid ester is 40% to 75% based on the total mass of the electrolyte.

[0015] In any embodiment, the linear carboxylic acid ester has the general structural formula of R 1 -COO-R 2 wherein R 1 and R 2 each independently includes one or more of an alkyl group of C 1 ~C 5 and a haloalkyl group of C 1 ~C 5

[0016] In any embodiment, the linear carboxylic acid ester includes one or more of ethyl acetate, methyl acetate, methyl propionate, propyl acetate, ethyl formate, and isopropyl formate.

[0017] When the above-mentioned type and mass percentage of linear carboxylic acid ester are used as the organic solvent in the electrolyte, due to the low viscosity of the linear carboxylic acid ester, it can effectively improve the electrolyte conductivity, thereby further improving the fast charging performance of the battery.

[0018] In any embodiment, the organic solvent includes a carbonate solvent, the carbonate solvent includes a linear carbonate and a cyclic carbonate, and based on the total mass of the electrolyte, the mass percentage of the linear carbonate is 10% to 40%.

[0019] In any embodiment, the cyclic carbonate includes one or more of ethylene carbonate and propylene carbonate, and the linear carbonate includes one or more of dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.

[0020] In any embodiment, the linear carbonate includes dimethyl carbonate, and based on the total mass of the electrolyte, the mass percentage of dimethyl carbonate is 5% to 15%.

[0021] When the above-mentioned type and mass percentage of carbonate are used as the organic solvent in the electrolyte, it can improve the side reactions and gas generation degree during the cycling of the battery, thereby enabling the battery to have good cycling performance at the same time.

[0022] In any embodiment, the electrolyte includes dimethyl carbonate and a linear carboxylic acid ester, and the mass ratio of the linear carboxylic acid ester to dimethyl carbonate is 2.0 to 7.0.

[0023] In any embodiment, the mass ratio of the linear carboxylic acid ester to dimethyl carbonate is 3.0 to 6.0.

[0024] ​When dimethyl carbonate and linear carboxylic acid ester with the above mass ratio are simultaneously used as organic solvents in the electrolyte, by combining the two solvents, the fast charging performance and cycling performance of the battery can be further improved while taking both into account.

[0025] In any embodiment, the electrolyte includes a lithium salt, and the mass ratio of the lithium salt is 13% to 20% based on the total mass of the electrolyte.

[0026] In any embodiment, the lithium salt includes at least two of lithium hexafluorophosphate and fluorosulfonylimide salts, and the fluorosulfonylimide salts include one or more of lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI).

[0027] Lithium hexafluorophosphate is not prone to gas generation during cycling, which can further improve the cycling performance of the battery; while fluorosulfonylimide salts have strong dissociation ability, which can further improve the fast charging performance of the battery.

[0028] In any embodiment, the lithium salt includes lithium hexafluorophosphate LiPF 6 and lithium bis(fluorosulfonyl)imide LiFSI.

[0029] In any embodiment, in the electrolyte, the mass ratio of lithium hexafluorophosphate LiPF 6 to lithium bis(fluorosulfonyl)imide LiFSI is 1.2:1 to 2:1.

[0030] When lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide within the above mass ratio range are simultaneously used in the electrolyte, the fast charging performance and cycling performance of the battery can be further improved while taking both into account.

[0031] In any embodiment, the electrolyte further contains an additive, and the additive includes a carbonate additive.

[0032] In any embodiment, based on the total mass of the electrolyte, the mass ratio of the carbonate additive in the electrolyte is 0.5% to 7%.

[0033] In any embodiment, the carbonate additive includes vinylene carbonate (VC) and fluoroethylene carbonate (FEC).

[0034] In the battery cell provided by the present application, a carbonate additive with a mass ratio within the above range, such as fluoroethylene carbonate and vinylene carbonate, is further added to the electrolyte. It can form a SEI film on the surface of the negative electrode, thereby reducing the side reactions occurring between the electrode sheet and the electrolyte, and further enabling the battery to have good cycling performance while taking both into account.

[0035] In any embodiment, the additive includes vinylene carbonate (VC); based on the total mass of the electrolyte, the mass proportion of vinylene carbonate (VC) in the electrolyte is 0.5% to 2%.

[0036] When vinylene carbonate within the above mass proportion range is added as an additive to the electrolyte, the formed SEI film is relatively stable, which is beneficial to further improving the cycle performance of the battery.

[0037] In any embodiment, the additive includes fluoroethylene carbonate (FEC); based on the total mass of the electrolyte, the mass proportion of fluoroethylene carbonate (FEC) in the electrolyte is 0.1% to 1%.

[0038] When fluoroethylene carbonate within the above mass proportion range is added as an additive to the electrolyte, the formed SEI film has a low impedance, which can further improve the fast charging performance of the battery.

[0039] In any embodiment, the general formula of the lithium-containing phosphate with an olivine structure is shown as Formula I, Li x A y Me a M b P 1-c X c Y z Formula I, wherein, 0.1 ≤ x ≤ 1.3, 0 ≤ y ≤ 1.3, and 0.9 ≤ x + y ≤ 1.3; 0.9 ≤ a ≤ 1.5, 0 ≤ b ≤ 0.5, and 0.9 ≤ a + b ≤ 1.5; 0 ≤ c ≤ 0.5; 3 ≤ z ≤ 5; A includes one or more of Na, K, and Mg; Me includes one or more of Mn, Fe, Co, and Ni; M includes one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; X includes one or more of S, Si, Cl, B, C, and N; Y includes one or more of O and F.

[0040] When the lithium-containing phosphate as the positive electrode active material has the above chemical general formula, the energy density of the battery can be further improved.

[0041] In any embodiment, M includes one or more of Al, Ti, V, and Mg.

[0042] In any embodiment, the positive electrode active material satisfies at least one of the following conditions: (1) The positive electrode active material contains Al element, and the mass content is 0.01% to 0.05% based on the total mass of the positive electrode active material; (2) The positive electrode active material contains Ti element, and the mass content is 0.01% to 0.03% based on the total mass of the positive electrode active material; (3) The positive electrode active material contains V element, and the mass content is 0.1% to 0.3% based on the total mass of the positive electrode active material; (4) The positive electrode active material contains Mg element, and the mass content is 0.001% to 0.01% based on the total mass of the positive electrode active material.

[0043] When the lithium-containing phosphate as the positive electrode active material contains elements such as Al, Ti, and V, its specific capacity can be further improved.

[0044] In any embodiment, in the cross-section of the positive electrode film layer along the thickness direction, the lithium-containing phosphate with olivine structure includes a first lithium-containing phosphate particle with a longest diameter of 0.05 μm to 0.3 μm and a second lithium-containing phosphate particle with a longest diameter of 1 μm to 3 μm.

[0045] In the battery cell provided by the present application, when the positive electrode active material includes lithium-containing phosphate particles with a longest diameter of 0.05 μm to 0.3 μm, it can further improve the DC internal resistance of the battery cell, thereby further reducing the heat generation of the battery, and making the battery have excellent safety performance.

[0046] In the battery cell provided by the present application, when the lithium-containing phosphate as the positive electrode active material simultaneously contains a first lithium-containing phosphate particle with a longest diameter of 0.05 μm to 0.3 μm and a second lithium-containing phosphate particle with a longest diameter of 1 μm to 3 μm, the tap density of the electrode can be effectively improved by the method of grading of large and small particles, so that the battery cell also has a relatively high energy density.

[0047] In any embodiment, in the cross-section of the positive electrode film layer along the thickness direction, the number of the first lithium-containing phosphate particles is greater than the number of the second lithium-containing phosphate particles.

[0048] In the lithium-containing phosphate as the positive electrode active material, when the number of the first lithium-containing phosphate particles with a longest diameter of 0.05 μm to 0.3 μm is greater than the number of the second lithium-containing phosphate particles with a longest diameter of 1 μm to 3 μm, the DC internal resistance and fast charging performance of the battery can be further improved.

[0049] In any embodiment, the size of the positive electrode film layer along the first direction is W 1 mm, and the size of the negative electrode film layer along the width direction of the negative electrode plate is W2 mm, where W 2 >W 1 , and W 2 and W 1 has a difference of 3 mm to 5 mm.

[0050] During the cycling process of the battery, lithium ions that cannot be embedded in the negative electrode in time may form lithium dendrites on the surface of the negative electrode, deteriorating the cycling performance of the battery. In the battery cell provided by the present application, when the size W 2 of the negative electrode film layer and the size W 1 of the positive electrode film layer have the above relationship, the formation of lithium dendrites on the surface of the negative electrode by lithium ions can be improved, so that the battery can simultaneously have better cycling performance.

[0051] In any embodiment, the tap density of the positive electrode plate is 2.3 g / cm 3 to 2.6 g / cm 3 .

[0052] In any embodiment, the tap density of the positive electrode plate is 2.4 g / cm 3 to 2.55 g / cm 3 .

[0053] When the tap density of the positive electrode plate is within the above range, the energy density of the battery can be further improved while ensuring the kinetic performance.

[0054] In any embodiment, the single-sided coating areal density of the positive electrode plate is 0.33 g / 1540.25 mm 2 to 0.4 g / 1540.25 mm 2 .

[0055] In any embodiment, the single-sided coating areal density of the positive electrode plate is 0.335 g / 1540.25 mm 2 to 0.38 g / 1540.25 mm 2 .

[0056] In the battery cell provided by the present application, when the coating areal density of the positive electrode film layer is within the above range, the energy density of the battery can be further improved, and the influence of thick coating on the electrochemical performance can be avoided, thereby further improving the fast charging performance of the battery.

[0057] In any embodiment, the tap density of the negative electrode plate is 1.3 g / cm 3 to 1.6 g / cm 3 .

[0058] In any embodiment, the tap density of the negative electrode plate is 1.35 g / cm 3 to 1.55 g / cm3 。

[0059] When the compaction density of the negative electrode plate is within the above range, the energy density of the battery can be further improved while ensuring the kinetic performance.

[0060] In any embodiment, the single-sided coating areal density of the negative electrode plate is 0.15 g / 1540.25mm 2 to 0.19 g / 1540.25mm 2 。

[0061] In any embodiment, the single-sided coating areal density of the negative electrode plate is 0.15 g / 1540.25mm 2 to 0.165 g / 1540.25mm 2 。

[0062] In the battery cell provided by the present application, when the coating areal density of the negative electrode film layer is within the above range, the energy density of the battery can be further improved, and the influence of thick coating on the electrochemical performance can be avoided, thereby further improving the fast charging performance of the battery.

[0063] In any embodiment, the thickness of the negative electrode current collector is 4 to 6 μm.

[0064] In any embodiment, the ratio of the single-sided thickness of the negative electrode film layer to the thickness of the negative electrode current collector is 12 to 20.

[0065] In any embodiment, the ratio of the single-sided thickness of the negative electrode film layer to the thickness of the negative electrode current collector is 13 to 20.

[0066] In the battery cell provided by the present application, when the ratio of the single-sided thickness of the negative electrode film layer to the thickness of the negative electrode current collector is within the above range, the improvement of the energy density and the fast charging performance of the battery can be further balanced.

[0067] In any embodiment, the negative electrode film layer includes a first negative electrode active material layer disposed on the surface of the negative electrode current collector and a second negative electrode active material layer disposed on the side of the first negative electrode active material layer away from the negative electrode current collector. The negative electrode active material in the first negative electrode active material layer includes first artificial graphite, and the negative electrode active material in the second negative electrode active material layer includes second artificial graphite. The average particle size Dv50 of the first artificial graphite is greater than the average particle size Dv50 of the second artificial graphite.

[0068] In any embodiment, the average particle size Dv50 of the first artificial graphite is 11 μm to 15 μm.

[0069] In any embodiment, the average particle size Dv50 of the second artificial graphite is 8 μm to 15 μm.

[0070] In any embodiment, the average particle size Dv50 of the second artificial graphite is 9.5 μm to 11.5 μm.

[0071] In the battery cell provided by the present application, when the above double-layer coating scheme is adopted in the negative electrode film layer, the kinetic performance of the battery can be further improved.

[0072] In any embodiment, the battery cell further includes a top cover, the top cover includes a positive electrode terminal and a negative electrode terminal with opposite polarities, and the positive electrode terminal and the negative electrode terminal are respectively used for electrically connecting with the positive electrode tab or the negative electrode tab.

[0073] In a conventional battery, a jumper is required to connect the electrode terminal and the tab, but this will reduce the utilization rate of the electrode assembly and the battery energy density. When the above structure is adopted in the battery cell provided by the present application, canceling the setting of the jumper can effectively solve this problem, reduce the battery internal resistance, and further take into account improving the battery energy density and fast charging performance.

[0074] In any embodiment, the battery cell further includes a housing, the housing is square, the thickness of the housing is 30 mm to 55 mm, the width is 150 mm to 250 mm, and the height is 90 mm to 120 mm.

[0075] In any embodiment, the battery cell is configured to have a charging time of 10 to 17 minutes from 10% SOC to 80% SOC at room temperature.

[0076] The battery cell provided by the present application has excellent fast charging performance.

[0077] A second aspect of the present application further provides a battery device, including the battery cell of the first aspect of the present application, and the battery device is at least one of a battery module, a battery pack, and an energy storage device.

[0078] A third aspect of the present application further provides an electrical device, including the battery cell of the first aspect of the present application or the battery device of the second aspect. Description of the Drawings

[0079] Figure 1 is one of the schematic diagrams of the sizes of the electrode film layers in an embodiment of the present application; Figure 2 is another schematic diagram of the sizes of the electrode film layers in an embodiment of the present application; Figure 3 is a third schematic diagram of the sizes of the electrode film layers in an embodiment of the present application; Figure 4 is a diagram of the observation result of the longitudinal section of the positive electrode tab in an embodiment of the present application by electron microscopy; Figure 5 It is a schematic diagram of an electrode sheet according to an embodiment of the present application; Figure 6 It is an exploded view of a battery cell according to an embodiment of the present application; Figure 7 It is one of the schematic diagrams of a battery cell according to an embodiment of the present application; Figure 8 It is another schematic diagram of a battery cell according to an embodiment of the present application; Figure 9 It is yet another schematic diagram of a battery cell according to an embodiment of the present application; Figure 10 It is a schematic diagram of a battery cell according to an embodiment of the present application; Figure 11 It is Figure 10 the exploded view of the battery cell shown in an embodiment of the present application; Figure 12 It is a schematic diagram of a battery module according to an embodiment of the present application; Figure 13 It is a schematic diagram of a battery pack according to an embodiment of the present application; Figure 14 It is Figure 13 the exploded view of the battery pack shown in an embodiment of the present application; Figure 15 It is a schematic diagram of an electrical device using a battery cell as a power source according to an embodiment of the present application.

[0080] Explanation of reference numerals: 1 Battery pack; 2 Upper box body; 3 Lower box body; 4 Battery module; 5 Battery cell; 51 Housing; 52 Electrode assembly; 53 Top cover assembly; 10 Battery cell; 11 Current collector; 11a Current collecting part; 111a Positive current collecting part; 112a Negative current collecting part; 11b Tab; 111b Positive tab; 112b Negative tab; F1 First direction; W 1 Dimension of the positive electrode film layer in the first direction; W 2 Dimension of the negative electrode film layer in the first direction; L Center line; 13 Top cover; 131 Electrode terminal; 14 Housing. Detailed implementation manners

[0081] Hereinafter, embodiments of the battery cell and the electrical device of the present application specifically disclosed will be 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.

[0082] 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" represents 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.

[0083] If there is no special instruction, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0084] If there is no special instruction, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0085] If there is no special instruction, all steps of the present application can be carried out sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method can include steps (a) and (b) carried out sequentially, or can also include steps (b) and (a) carried out sequentially. For example, it is mentioned that the method may further include step (c), which means that step (c) can be added to the method in any order. For example, the method can include steps (a), (b), and (c), or can also include steps (a), (c), and (b), or can also include steps (c), (a), and (b), etc.

[0086] Unless otherwise specified, the terms "comprising" and "including" as used in this application are open-ended and can also be closed-ended. For example, the terms "comprising" and "including" can mean that other components not listed may also be included or comprised, or it can mean that only the listed components are included or comprised.

[0087] Unless otherwise specified, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) while B is true (or exists); or both A and B are true (or exist).

[0088] In recent years, with the increasing demand for batteries as an energy source, higher requirements have been put forward for the fast charging performance of batteries. However, fast charging batteries will release a large amount of heat in a short time during charging, which may pose certain safety hazards. Therefore, if the battery dynamics performance can be improved while also taking into account the improvement of the DC impedance of the battery, the comprehensive performance of the battery can be further improved.

[0089] To solve the above problems, this application provides a battery cell, comprising a positive electrode plate, a negative electrode plate, an electrolyte, and a separator located between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive current collector and a positive electrode film layer provided on at least one surface of the positive current collector. The positive electrode film layer includes a positive active material, and the positive active material includes a lithium-containing phosphate with an olivine structure. The negative electrode plate includes a negative current collector and a negative electrode film layer provided on at least one surface of the negative current collector. The negative electrode film layer includes a negative active material, and the average particle size Dv50 of the negative active material is 8 μm to 15 μm. The negative active material includes graphite. The negative current collector includes a negative current collecting portion and at least two negative electrode tabs provided on the same side of the negative current collecting portion. The negative electrode tabs extend from the negative current collecting portion in a first direction. Among them, the distance between the centerlines of two adjacent negative electrode tabs is 10 mm to 350 mm, and the centerline is parallel to the first direction.

[0090] As used herein, "average particle size Dv50" refers to: in the particle size distribution of particles, starting from the small particle size side, the particle size corresponding to when the cumulative volume distribution percentage reaches 50%. Its measurement method can refer to GB / T19077-2016 / ISO13320:2009 and be measured using a Malvern 2000 (MasterSizer 2000) laser particle size analyzer.

[0091] In some embodiments, in combination with Figure 5As shown, the current collector 11 includes a current collecting portion 11a and at least two tabs 11b provided on the same side of the current collecting portion 11a, and the tabs 11b extend from the current collecting portion 11a along the first direction F1.

[0092] In some embodiments, in combination with Figure 5 As shown, the center line L refers to the symmetry axis passing through the midpoint of the tab 11b along the length direction of the current collector 11, and the center line L is parallel to the first direction F1. In some embodiments, the dimensions of each tab 11b along the length direction of the current collector 11 are equal.

[0093] In some embodiments, in combination with Figure 5 As shown, the distance between the center lines L of two adjacent tabs 11b includes S1 or S2, where S1 and S2 may be equal (in this case, the adjacent tabs are equally spaced), and S1 and S2 may also be unequal (in this case, the adjacent tabs are unequally spaced).

[0094] In some embodiments, in combination with Figures 1 - 3 、 Figures 5 - 6 As shown, the current collector 11 may be a positive current collector or a negative current collector, the current collecting portion 11a may be a positive current collecting portion 111a or a negative current collecting portion 112a, and the tab 11b may be a positive tab 111b or a negative tab 112b.

[0095] In this application, by using a negative active material with a small particle size, the transmission path of lithium ions inside the negative active material during charging is improved, which is beneficial to improving the fast charging ability of the battery cell. However, when the fast charging ability of the battery cell is improved, the corresponding charging current it withstands also increases. At this time, if the tab structure of the negative electrode is not set reasonably, it will cause the internal heat generation of the battery cell to accumulate during fast charging, the internal temperature of the battery increases, and adverse reactions such as electrolyte gas generation and an increase in the impedance of the solid electrolyte interface membrane (SEI membrane) of the negative electrode occur, thereby increasing the battery internal resistance and affecting the performance of the battery cell. In this application, by adopting a negative tab arrangement within a reasonable distance range, the heat accumulation inside the battery cell during the improvement of the fast charging ability is effectively reduced, the internal temperature rise is reduced, and the growth of the direct current internal resistance (DCR) of the battery cell is inhibited.

[0096] [Negative electrode plate] In some embodiments, the negative electrode plate includes a negative current collector and a negative electrode film layer provided on at least one surface of the negative current collector. As an example, the negative current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode film layer is provided on either or both of the two opposite surfaces of the negative current collector.

[0097] In some embodiments, the negative electrode film layer includes a negative electrode active material.

[0098] In some embodiments, the average particle size Dv50 of the negative electrode active material is from 8 μm to 15 μm, such as 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc., or other values not listed within the range of 8 μm to 15 μm. In some embodiments, the negative electrode active material includes graphite.

[0099] In the battery cell provided by the present application, when the graphite serving as the negative electrode active material has a particle size within the above range, it has a relatively large specific surface area, the migration channels between the graphite layers for lithium ions increase, and the migration path becomes shorter, thereby accelerating the intercalation and deintercalation rate of lithium ions between the graphite layers, enabling the battery cell to have good fast charging performance; at the same time, when the graphite serving as the negative electrode active material has a particle size within the above range, it can also improve the DC internal resistance of the battery cell, thereby reducing the heat generation of the battery and enabling the battery to have good safety performance.

[0100] In some embodiments, the average particle size Dv50 of the negative electrode active material is from 9.5 μm to 11.5 μm, such as 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, etc., or other values not listed within the range of 9.5 μm to 11.5 μm.

[0101] When the negative electrode active material (such as graphite) has a particle size within the above range, it can further improve the fast charging performance and DC internal resistance of the battery, and at the same time enable the battery to have good cycle performance.

[0102] In some embodiments, the negative electrode film layer includes at least two negative electrode active material layers. In some embodiments, the negative electrode film layer includes a first negative electrode active material layer disposed on the surface of the negative electrode current collector and a second negative electrode active material layer disposed on the side of the first negative electrode active material layer away from the negative electrode current collector. The negative electrode active material in the first negative electrode active material layer includes first artificial graphite, and the negative electrode active material in the second negative electrode active material layer includes second artificial graphite. The average particle size Dv50 of the first artificial graphite is greater than the average particle size Dv50 of the second artificial graphite.

[0103] In some embodiments, the average particle size Dv50 of the first artificial graphite is from 11 μm to 15 μm, such as 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc., or other values not listed within the range of 11 μm to 15 μm.

[0104] In some embodiments, the average particle size Dv50 of the second artificial graphite is 8 μm to 15 μm, such as 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc., or other unlisted values within the range of 8 μm to 15 μm.

[0105] In some embodiments, the average particle size Dv50 of the second artificial graphite is 9.5 μm to 11.5 μm, such as 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, etc., or other unlisted values within the range of 9.5 μm to 11.5 μm.

[0106] In the battery cell provided by the present application, when the above double-layer coating scheme is adopted in the negative electrode film layer, the kinetic performance of the battery can be further improved.

[0107] In some embodiments, the negative electrode film layer may further optionally include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0108] In some embodiments, the negative electrode film layer may further optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0109] In some embodiments, the negative electrode film layer may further optionally include other additives, such as a thickener (such as sodium carboxymethyl cellulose (CMC-Na)), etc.

[0110] In some embodiments, the areal density of the single-sided negative electrode film layer is 0.15 g / 1540.25mm 2 to 0.19 g / 1540.25mm 2 , such as 0.15 g / 1540.25mm 2 , 0.16 g / 1540.25mm 2 , 0.17 g / 1540.25mm 2 , 0.18 g / 1540.25mm 2 , 0.19 g / 1540.25mm 2 etc., or other unlisted values within the range of 0.15 g / 1540.25mm 2 to 0.19 g / 1540.25mm 2 range.

[0111] In some embodiments, the areal density of one side of the negative electrode film layer is 0.15 g / 1540.25 mm 2 to 0.165 g / 1540.25 mm 2 .

[0112] As used herein, the "areal density" of the positive electrode film layer or the negative electrode film layer has the meaning well-known in the art and can be measured by methods known in the art. For example, take a negative electrode sheet after single-sided coating and cold pressing (if it is a double-sided coated negative electrode sheet, the negative electrode film layer on one side can be wiped off first), punch it into small round pieces with an area of S1, weigh it, and record it as M1. Then wipe off the negative electrode film layer of the above-mentioned weighed negative electrode sheet, weigh the weight of the negative electrode current collector, and record it as M0. The areal density of the negative electrode film layer = (the weight M1 of the negative electrode sheet - the weight M0 of the negative electrode current collector) / 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.

[0113] In the battery cell provided by the present application, when the coating areal density of the negative electrode film layer is within the above range, the energy density of the battery can be further improved, and the influence of thick coating on the electrochemical performance can be avoided, thereby further improving the fast charging performance of the battery.

[0114] In some embodiments, the negative electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, copper foil can be used. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0115] In some embodiments, the thickness of the negative electrode current collector is 4 μm to 6 μm, such as 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, etc., or other unlisted values within the range of 4 μm to 6 μm.

[0116] In some embodiments, the ratio of the single-sided thickness of the negative electrode film layer to the thickness of the negative electrode current collector is 12 to 20, such as 12, 13, 14, 15, 16, 17, 18, 19, 20, etc., or other unlisted values within the range of 12 to 20.

[0117] In some embodiments, the ratio of the single-sided thickness of the negative electrode film layer to the thickness of the negative electrode current collector is 13 to 20.

[0118] In some embodiments, the single-sided thickness of the negative electrode film layer corresponds to the single-sided thickness of the negative electrode film layer of the battery cell corresponding to the 0% SOC state. The battery cell in the 0% SOC state means: discharging the battery cell at 1 / 3C to 2.0V and then discharging it at 0.05C to 2.0V. In the battery cell provided in the present application, when the ratio of the single-sided thickness of the negative electrode film layer to the thickness of the negative electrode current collector is within the above range, it can further balance the improvement of the energy density and fast charging performance of the battery.

[0119] In some embodiments, the negative electrode current collector includes a negative electrode current collecting portion and at least two negative electrode tabs provided on the same side of the negative electrode current collecting portion, and the negative electrode tabs extend from the negative electrode current collecting portion along a first direction. In some embodiments, the distance between the centerlines of two adjacent negative electrode tabs is 10 mm to 350 mm, and the centerline is parallel to the first direction, such as 10 mm, 20 mm, 40 mm, 60 mm, 80 mm, 100 mm, 120 mm, 140 mm, 160 mm, 180 mm, 200 mm, 220 mm, 240 mm, 260 mm, 280 mm, 300 mm, 320 mm, 340 mm, 350 mm, etc., or other unlisted values within the range of 10 mm to 350 mm.

[0120] In some embodiments, the distance between the centerlines of two adjacent negative electrode tabs is 20 mm to 330 mm, and the centerline is parallel to the first direction, such as 20 mm, 40 mm, 60 mm, 80 mm, 100 mm, 120 mm, 140 mm, 160 mm, 180 mm, 200 mm, 220 mm, 240 mm, 260 mm, 280 mm, 300 mm, 320 mm, 330 mm, etc., or other unlisted values within the range of 20 mm to 330 mm.

[0121] In the battery cell provided in the present application, when the positive and negative current collectors include at least two tabs having the above structural features, it can further improve the overcurrent capacity, improve the DC internal resistance of the battery cell, thereby further reducing the heat generation of the battery and making the battery have better safety performance.

[0122] In some embodiments, the negative electrode plate can be prepared by the following method: dispersing the components for preparing the negative electrode plate, such as negative electrode active material, conductive agent, binder and any other components, in a solvent (such as deionized water) to form a negative electrode slurry; coating the negative electrode slurry on the negative electrode current collector, and after processes such as drying and cold pressing, the negative electrode plate can be obtained.

[0123] In some embodiments, the compaction density of the negative electrode plate is 1.3 g / cm 3 to 1.6 g / cm 3, such as 1.3 g / cm 3 , 1.4 g / cm 3 , 1.5 g / cm 3 , 1.6 g / cm 3 etc., or other unlisted values within the range from 1.3 g / cm 3 to 1.6 g / cm 3 .

[0124] In some embodiments, the compaction density of the negative electrode tab is from 1.35 g / cm 3 to 1.55 g / cm 3 , such as 1.35 g / cm 3 , 1.40 g / cm 3 , 1.45 g / cm 3 , 1.50 g / cm 3 , 1.55 g / cm 3 etc., or other unlisted values within the range from 1.35 g / cm 3 to 1.55 g / cm 3 .

[0125] In some embodiments, the compaction density of the negative electrode tab corresponds to the compaction density of the negative electrode film layer of the battery cell corresponding to the 0% SOC state. The battery cell in the 0% SOC state means: the battery cell is discharged to 2.0 V at 1 / 3 C and then discharged to 2.0 V at 0.05 C. When used herein, the "compaction density" of the electrode tab is: compaction density = areal density / (electrode tab thickness - current collector thickness), and its measurement method can refer to GB / T24533-2009.

[0126] When the compaction density of the negative electrode tab is within the above range, the energy density of the battery can be further improved while ensuring the kinetic performance.

[0127] [Positive electrode tab] In some embodiments, the positive electrode tab includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector. As an example, the positive current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0128] In some embodiments, the positive electrode film layer includes a positive active material.

[0129] In some embodiments, the positive active material includes a lithium-containing phosphate in an olivine structure.

[0130] In some embodiments, the general formula of the lithium-containing phosphate in the olivine structure is as shown in Formula I, Li x Ay Me a M b P 1-c X c Y z Formula I, wherein, 0.1 ≤ x ≤ 1.3, 0 ≤ y ≤ 1.3, and 0.9 ≤ x + y ≤ 1.3; 0.9 ≤ a ≤ 1.5, 0 ≤ b ≤ 0.5, and 0.9 ≤ a + b ≤ 1.5; 0 ≤ c ≤ 0.5; 3 ≤ z ≤ 5; A includes one or more of Na, K, and Mg; Me includes one or more of Mn, Fe, Co, and Ni; M includes one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; X includes one or more of S, Si, Cl, B, C, and N; Y includes one or more of O and F.

[0131] As used herein, "the general formula of the lithium-containing phosphate having an olivine structure is as shown in Formula I" is not limited to the substances represented by the general formula of the molecule, but also includes other substances formed by further appropriate modification on the basis of the general formula of the molecule, which are not limited herein. The use of "general formula" is only for convenience of description and does not intend to limit the present application. It can be understood that new materials or new substances obtained by appropriate modification on the basis of the listed cathode active materials are also within the scope of the cathode active materials. The aforementioned appropriate modification refers to the acceptable modification methods for the cathode active materials, and non-limiting examples include coating modification.

[0132] When the lithium-containing phosphate as the cathode active material has the above chemical general formula, the energy density of the battery can be further improved.

[0133] In some embodiments, M includes one or more of Al, Ti, V, and Mg.

[0134] In some embodiments, the cathode active material contains Al element, and its mass content is 0.001% - 0.05%, optionally 0.01% - 0.05%, based on the total mass of the cathode active material. For example, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, etc., or other unlisted values within the range of 0.001% - 0.05%, based on the total mass of the cathode active material.

[0135] In some embodiments, the positive electrode active material contains Ti element, and its mass content is 0.001% to 0.03%, optionally 0.01 to 0.03%, based on the total mass of the positive electrode active material. For example, 0.001%, 0.01%, 0.02%, 0.03%, etc., or other unlisted values within the range of 0.001% to 0.03%, based on the total mass of the positive electrode active material.

[0136] In some embodiments, the positive electrode active material contains V element, and its mass content is 0.001% to 0.3%, optionally 0.1 to 0.3%, based on the total mass of the positive electrode active material. For example, 0.001%, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, etc., or other unlisted values within the range of 0.001% to 0.3%, based on the total mass of the positive electrode active material.

[0137] In some embodiments, the positive electrode active material contains Mg element, and the mass content is 0.001% to 0.01%, based on the total mass of the positive electrode active material. Optionally, it can be 0.001%, 0.002%, 0.005%, 0.01%, or other unlisted values within the range of 0.001% to 0.01%, based on the total mass of the positive electrode active material.

[0138] When the lithium-containing phosphate as the positive electrode active material contains elements such as Al, Ti, V, and Mg, it can further improve the structural stability of the material and enhance the cycling performance.

[0139] In some embodiments, in the cross-section of the positive electrode film layer along the thickness direction, the lithium-containing phosphate with olivine structure includes a first lithium-containing phosphate particle with a longest diameter of 0.05 μm to 0.3 μm and a second lithium-containing phosphate particle with a longest diameter of 1 μm to 3 μm.

[0140] In some embodiments, in the cross-section of the positive electrode film layer along the thickness direction, the lithium-containing phosphate with olivine structure includes a first lithium-containing phosphate particle with a longest diameter of 0.05 μm to 0.3 μm, such as 0.05 μm, 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, etc., or other unlisted values within the range of 0.05 μm to 0.3 μm.

[0141] In some embodiments, in the cross-section of the positive electrode film layer along the thickness direction, the lithium-containing phosphate with olivine structure includes a second lithium-containing phosphate particle with a longest diameter of 1 μm to 3 μm, such as 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, etc., or other unlisted values within the range of 1 μm to 3 μm.

[0142] In some embodiments, since the first lithium-containing phosphate and the second lithium-containing phosphate have been fully mixed and uniformly coated on the current collector to form the positive electrode film layer during the preparation of the slurry, any cross-section taken along the thickness direction of the electrode can represent the particle size and distribution of the lithium-containing phosphate in the entire electrode; when selecting the cross-section, it is preferable to select a relatively flat cross-section in the middle of the electrode to more clearly observe the distribution of the lithium-containing phosphate therein.

[0143] In some embodiments, the "longest diameter" refers to: cutting the positive electrode along the thickness direction of the electrode to expose the longitudinal section of the positive electrode film layer; determining the longest diameter of the lithium-containing phosphate particles through a scanning electron microscope (SEM) test on the longitudinal section of the positive electrode film layer. Specifically, Among the distances between any two points on the outer peripheral line of the lithium-containing phosphate particles, the maximum value is the "longest diameter" of the particles. In some embodiments, as Figure 4 shown in the longitudinal section of the electrode along the thickness direction, which shows the longest diameter of a single particle satisfying the first lithium-containing phosphate particles (with the longest diameter of 0.05 μm to 0.3 μm), and also shows the shortest diameter of a single particle satisfying the second lithium-containing phosphate particles (with the longest diameter of 1 μm to 3 μm).

[0144] In the battery cell provided by the present application, when the positive electrode active material contains lithium-containing phosphate particles with a longest diameter of 0.05 μm to 0.3 μm, it can further improve the DC internal resistance of the battery cell, thereby further reducing the heat generation of the battery, enabling the battery to have excellent safety performance.

[0145] In the battery cell provided by the present application, when the lithium-containing phosphate as the positive electrode active material simultaneously contains first lithium-containing phosphate particles with a longest diameter of 0.05 μm to 0.3 μm and second lithium-containing phosphate particles with a longest diameter of 1 μm to 3 μm, the tap density of the electrode can be effectively improved through the grading of large and small particles, thereby enabling the battery cell to also have a relatively high energy density.

[0146] In some embodiments, in the cross-section of the positive electrode film layer along the thickness direction, the number of the first lithium-containing phosphate particles is greater than the number of the second lithium-containing phosphate particles.

[0147] In the lithium-containing phosphate as the positive electrode active material, when the number of the first lithium-containing phosphate particles with a longest diameter of 0.05 μm to 0.3 μm is greater than the number of the second lithium-containing phosphate particles with a longest diameter of 1 μm to 3 μm, the improvement of the DC internal resistance and the fast charging performance of the battery can be further balanced.

[0148] It should be noted that the first lithium-containing phosphate particle material with a smaller size having a longest diameter ranging from 0.05 μm to 0.3 μm is one of the cathode active materials of the battery monomer of the present application, and the particle size range of 0.05 μm to 0.3 μm is a characteristic parameter of the material itself.

[0149] The second lithium-containing phosphate particle material with a larger size having a longest diameter ranging from 1 μm to 3 μm is one of the cathode active materials of the battery monomer of the present application, and the particle size range of 1 μm to 3 μm is a characteristic parameter of the material itself.

[0150] Those skilled in the art can mix the lithium-containing phosphate particle materials in the above two size ranges according to actual needs.

[0151] In some embodiments, the cathode film layer may further optionally include a cathode conductive agent. The present application does not particularly limit the type of the cathode conductive agent. By way of example, the cathode conductive agent includes at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0152] In some embodiments, the cathode film layer may further optionally include a cathode binder. The present application does not particularly limit the type of the cathode binder. By way of example, the cathode binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0153] In some embodiments, the areal density of the single-sided cathode film layer is 0.33 g / 1540.25 mm 2 to 0.4 g / 1540.25 mm 2 , such as 0.33 g / 1540.25 mm 2 , 0.34 g / 1540.25 mm 2 , 0.35 g / 1540.25 mm 2 , 0.36 g / 1540.25 mm 2 , 0.37 g / 1540.25 mm 2 , 0.38 g / 1540.25 mm 2 , 0.39 g / 1540.25 mm 2 , 0.4 g / 1540.25 mm 2 etc., or other unlisted values within the range of 0.33 g / 1540.25 mm 2 to 0.4 g / 1540.25 mm 2 range.

[0154] In some embodiments, the areal density of one side of the positive electrode film layer is 0.335 g / 1540.25 mm 2 to 0.38 g / 1540.25 mm 2 .

[0155] In the battery cell provided by the present application, when the coating areal density of the positive electrode film layer is within the above range, the energy density of the battery can be further improved, and the influence of thick coating on the electrochemical performance can be avoided, thereby further improving the fast charging performance of the battery.

[0156] In some embodiments, the size of the positive electrode film layer along the first direction is W 1 mm, and the size of the negative electrode film layer along the first direction is W 2 mm, where W 2 > W 1 , and the difference between W 2 and W 1 is 3 mm to 5 mm, such as 3 mm, 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm, 4 mm, 4.2 mm, 4.4 mm, 4.6 mm, 4.8 mm, 5 mm, etc., or other unlisted values within the range of 3 mm to 5 mm.

[0157] In some embodiments, the positive electrode sheet, the negative electrode sheet and the separator can be made into an electrode assembly by a winding process or a stacking process.

[0158] In some embodiments, the battery cell is a wound battery. As shown in Figure 3 , after the electrode sheet is unfolded from the wound state, the positive current collector includes a positive current collecting portion 111a and at least two positive electrode tabs 111b provided on the same side of the positive current collecting portion 111a. The positive electrode tabs 111b extend from the positive current collecting portion 111a along the first direction F1; the negative current collector includes a negative current collecting portion 112a and at least two negative electrode tabs 112b provided on the same side of the negative current collecting portion 112a. The negative electrode tabs 112b extend from the negative current collecting portion 112a along the first direction F1. Among them, the size W 2 of the negative electrode film layer along the first direction > the size W 1 of the positive electrode film layer along the first direction, and the difference is 3 mm to 5 mm.

[0159] In some embodiments, the battery cell is a stacked battery. As shown in Figure 1 and Figure 2As shown, each electrode sheet forms an electrode assembly in a stacked state. Among them, each positive electrode sheet includes a positive current collector, and the positive current collector includes a positive current collecting portion 111a and a positive electrode tab 111b provided on the positive current collecting portion 111a. The positive electrode tab 111b extends from the positive current collecting portion 111a along the first direction F1; each negative electrode sheet includes a negative current collector, and the negative current collector includes a negative current collecting portion 112a and a negative electrode tab 112b provided on the negative current collecting portion 112a. The negative electrode tab 112b extends from the negative current collecting portion 112a along the first direction F1. Among them, the size W of the negative electrode film layer in the first direction 2 > the size W of the positive electrode film layer in the first direction 1 , and the difference is 3 mm to 5 mm.

[0160] During the cycling of the battery, lithium ions that cannot be embedded in the negative electrode in time may form lithium dendrites on the surface of the negative electrode, deteriorating the cycling performance of the battery. In the battery cell provided in the present application, when the size W of the negative electrode film layer 2 and the size W of the positive electrode film layer 1 have the above relationship, the formation of lithium dendrites on the surface of the negative electrode can be improved, so that the battery can simultaneously have good cycling performance.

[0161] In some embodiments, the positive current collector can be a metal foil or a composite current collector. As an example of the metal foil, aluminum foil can be used. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer can include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0162] In some embodiments, the thickness of the positive current collector is 10 μm to 15 μm, such as 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc., or other unlisted values within the range of 10 μm to 15 μm.

[0163] In some embodiments, the ratio of the single-sided thickness of the positive electrode film layer to the thickness of the positive current collector is 5 to 12, such as 5, 6, 7, 8, 9, 10, 11, 12, etc., or other unlisted values within the range of 5 to 12.

[0164] In some embodiments, the ratio of the single-sided thickness of the positive electrode film layer to the thickness of the positive current collector is 6 to 10.

[0165] In the battery cell provided by the present application, when the ratio of the single-sided thickness of the positive electrode film layer to the thickness of the positive electrode current collector is within the above range, the thickness of the current collector is within a suitable range, which will not cause energy density loss due to excessive thickness, nor will it cause problems such as poor over-current capacity and low tensile strength resulting in pole piece cracking due to excessive thinness, further taking into account the improvement of the energy density and fast charging performance of the battery.

[0166] In some embodiments, the positive electrode current collector includes a positive electrode current collecting portion and at least two positive electrode tabs provided on the same side of the positive electrode current collecting portion, and the positive electrode tabs extend from the positive electrode current collecting portion along a first direction. In some embodiments, the distance between the center lines of two adjacent positive electrode tabs is 10 mm to 350 mm, and the center line is parallel to the first direction, such as 10 mm, 20 mm, 40 mm, 60 mm, 80 mm, 100 mm, 120 mm, 140 mm, 160 mm, 180 mm, 200 mm, 220 mm, 240 mm, 260 mm, 280 mm, 300 mm, 320 mm, 340 mm, 350 mm, etc., or other unlisted values within the range of 10 mm to 350 mm.

[0167] In some embodiments, the distance between the center lines of two adjacent positive electrode tabs is 20 mm to 330 mm, such as 20 mm, 40 mm, 60 mm, 80 mm, 100 mm, 120 mm, 140 mm, 160 mm, 180 mm, 200 mm, 220 mm, 240 mm, 260 mm, 280 mm, 300 mm, 320 mm, 330 mm, etc., or other unlisted values within the range of 20 mm to 330 mm.

[0168] In the battery cell provided by the present application, when the positive and negative current collectors include at least two tabs having the above structural features, it can further improve the over-current capacity, improve the DC internal resistance of the battery cell, thereby further reducing the heat generation of the battery and making the battery have better safety performance.

[0169] In some embodiments, the positive electrode pole piece can be prepared by the following method: dispersing the above components for preparing the positive electrode pole piece, such as positive electrode active material, conductive agent, binder and any other components, in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on the positive electrode current collector, and after processes such as drying and cold pressing, the positive electrode pole piece can be obtained.

[0170] In some embodiments, the tap density of the positive electrode pole piece is 2.3 g / cm 3 to 2.6 g / cm 3 , such as 2.30 g / cm 3 、2.35 g / cm 3, 2.40 g / cm 3 , 2.45 g / cm 3 , 2.50 g / cm 3 , 2.55 g / cm 3 , 2.60 g / cm 3 , etc., or values other than those listed within the range of 2.3 g / cm 3 to 2.6 g / cm 3 that are not listed.

[0171] In some embodiments, the compaction density of the positive electrode sheet is 2.4 g / cm 3 to 2.55 g / cm 3 .

[0172] When the compaction density of the positive electrode sheet is within the above range, the energy density of the battery can be further improved while ensuring the kinetic performance.

[0173] In some embodiments, the compaction density of the positive electrode sheet corresponds to the compaction density of the positive electrode film layer of the battery cell in the 0% SOC state. The battery cell in the 0% SOC state refers to the state in which the battery cell is discharged to 2.0 V at 1 / 3 C and then discharged to 2.0 V at 0.05 C.

[0174] [Electrolyte] The electrolyte plays a role in conducting ions between the positive electrode sheet and the negative electrode sheet. For example, the electrolyte can be liquid, solid, or gel-like.

[0175] In some embodiments, the electrolyte uses an electrolytic solution. The electrolytic solution includes an electrolyte salt and an organic solvent.

[0176] In the embodiments of the present application, the types and contents of the organic components in the electrolytic solution have meanings well-known in the art, and can be detected using equipment and methods well-known in the art. For example, the composition of the electrolytic solution can be measured by liquid chromatography, gas chromatography, ion chromatography, liquid nuclear magnetic resonance, etc. Exemplarily, qualitative and quantitative analysis of the organic components in the electrolytic solution can be performed by gas chromatography with reference to GB / T9722-2006 "General Rules for Gas Chromatography of Chemical Reagents".

[0177] The test sample in the embodiments of the present application can be a newly prepared electrolytic solution as the sample, or the free electrolytic solution obtained from the battery after the battery is fully discharged (discharged to the lower cut-off voltage so that the charged state of the battery is approximately 0% SOC) can be used as the sample.

[0178] In the embodiments of the present application, the types and contents of inorganic components / lithium salt concentration in the electrolyte have the meanings well-known in the art, and can be detected by equipment and methods well-known in the art. For example, reference can be made to the standard JY / T 020-1996 "General Rules for Ion Chromatographic Analysis Methods" to qualitatively or quantitatively analyze the inorganic components / lithium salt concentration in the electrolyte by ion chromatography analysis method. In the embodiments of the present application, newly prepared electrolyte can be taken as a sample, or the battery can be discharged (discharged to the lower cut-off voltage so that the charged state of the battery is about 0% SOC), and the free electrolyte obtained from the battery can be taken as a sample, and detected by ion chromatography analysis method.

[0179] In some embodiments, the organic solvent includes a carboxylic acid ester solvent and a carbonate solvent.

[0180] In the battery monomer provided by the present application, when the above types of organic solvents are used in the electrolyte, the kinetic performance of the battery can be further improved.

[0181] In some embodiments, the organic solvent includes a linear carboxylic acid ester. Based on the total mass of the electrolyte, the mass ratio of the linear carboxylic acid ester is 40% to 75%, such as 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, etc., or other unlisted values within the range of 40% to 75%.

[0182] In some embodiments, the linear carboxylic acid ester has the structural general formula of R 1 -COO-R 2 wherein R 1 and R 2 each independently includes one or more of an alkyl group of C 1 ~C 5 and a haloalkyl group of C 1 ~C 5

[0183] In some embodiments, the linear carboxylic acid ester includes one or more of ethyl acetate, methyl acetate, methyl propionate, propyl acetate, ethyl formate, and isopropyl formate.

[0184] When the linear carboxylic acid ester of the above type and mass ratio is used as the organic solvent in the electrolyte, due to the low viscosity of the linear carboxylic acid ester, it can effectively improve the electrolyte conductivity, thereby further improving the fast charging performance of the battery.

[0185] In some embodiments, the organic solvent includes a carbonate solvent, and the carbonate solvent includes a linear carbonate and a cyclic carbonate. Based on the total mass of the electrolyte, the mass percentage of the linear carbonate is 10% to 40%, such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc., or other unlisted values within the range of 10% to 40%.

[0186] In some embodiments, the cyclic carbonate includes one or more of ethylene carbonate and propylene carbonate, and the linear carbonate includes one or more of dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.

[0187] In some embodiments, the linear carbonate includes dimethyl carbonate. Based on the total mass of the electrolyte, the mass percentage of dimethyl carbonate is 5% to 15%, such as 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc., or other unlisted values within the range of 5% to 15%.

[0188] When the carbonate of the above type and mass percentage is used as the organic solvent in the electrolyte, side reactions and gas generation during battery cycling can be improved, so that the battery can simultaneously have good cycling performance.

[0189] In some embodiments, the organic solvent includes dimethyl carbonate and a linear carboxylic acid ester, and the mass ratio of the linear carboxylic acid ester to dimethyl carbonate is 2.0 to 7.0, such as 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, etc., or other unlisted values within the range of 2.0 to 7.0.

[0190] In some embodiments, the organic solvent includes dimethyl carbonate and a linear carboxylic acid ester, and the mass ratio of the linear carboxylic acid ester to dimethyl carbonate is 3.0 to 6.0.

[0191] When dimethyl carbonate and a linear carboxylic acid ester with the above mass ratio are simultaneously used as the organic solvent in the electrolyte, by combining the two solvents, the fast charging performance and cycling performance of the battery can be further improved.

[0192] In some embodiments, the electrolyte further includes a lithium salt, such as at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro bis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0193] In some embodiments, based on the total mass of the electrolyte, the mass percentage of the lithium salt is 13% to 20%, such as 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc., or other unlisted values within the range of 13% to 20%.

[0194] In some embodiments, the lithium salt includes at least two of lithium hexafluorophosphate LiPF 6 , and at least two of fluorosulfonylimide salts, and the fluorosulfonylimide salts include one or more of lithium bis(fluorosulfonyl)imide LiFSI and lithium bis(trifluoromethanesulfonyl)imide LiTFSI.

[0195] Lithium hexafluorophosphate is not prone to gas generation during cycling, which can further improve the cycling performance of the battery; while the fluorosulfonylimide salt has strong dissociation ability, which can further improve the fast charging performance of the battery.

[0196] In some embodiments, the lithium salt includes lithium hexafluorophosphate LiPF 6 and lithium bis(fluorosulfonyl)imide LiFSI.

[0197] In some embodiments, in the electrolyte, the mass ratio of lithium hexafluorophosphate LiPF 6 to lithium bis(fluorosulfonyl)imide LiFSI is 1.2:1 to 2:1, such as 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, etc., or other unlisted values within the range of 1.2:1 to 2:1.

[0198] When lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide within the above mass ratio range are simultaneously used in the electrolyte, the fast charging performance and cycling performance of the battery can be further balanced.

[0199] In some embodiments, the electrolyte further includes additives. For example, the additives can include negative electrode film-forming additives, positive electrode film-forming additives, and can also include additives that can improve certain performance of the battery, such as additives that improve the overcharging performance of the battery, additives that improve the high-temperature or low-temperature performance of the battery, etc.

[0200] In some embodiments, the electrolyte includes carbonate additives, and the carbonate additives include fluoroethylene carbonate FEC and vinylene carbonate VC.

[0201] In some embodiments, based on the total mass of the electrolyte, the mass percentage of the carbonate additives is 0.5% to 7%, such as 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 6.5%, 7%, etc., or other unlisted values within the range of 0.5% to 7%.

[0202] In the battery cell provided by the present application, a carbonate additive within the above-mentioned mass ratio range is further added to the electrolyte, such as fluoroethylene carbonate and vinylene carbonate, which can form a SEI film on the surface of the negative electrode, thereby reducing the side reactions occurring between the electrode sheet and the electrolyte, and further enabling the battery to have good cycle performance.

[0203] In some embodiments, the electrolyte includes vinylene carbonate (VC). Based on the total mass of the electrolyte, the mass ratio of vinylene carbonate (VC) in the electrolyte is 0.5% to 2%, such as 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, etc., or other unlisted values within the range of 0.5% to 2%.

[0204] When vinylene carbonate within the above-mentioned mass ratio range is added as an additive to the electrolyte, the formed SEI film is relatively stable, which is beneficial to further improving the cycle performance of the battery.

[0205] In some embodiments, the electrolyte includes fluoroethylene carbonate (FEC). Based on the total mass of the electrolyte, the mass ratio of fluoroethylene carbonate (FEC) in the electrolyte is 0.1% to 1%, such as 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, etc., or other unlisted values within the range of 0.1% to 1%.

[0206] When fluoroethylene carbonate within the above-mentioned mass ratio range is added as an additive to the electrolyte, the formed SEI film has a low impedance, which can further improve the fast charging performance of the battery.

[0207] [Separator] In some embodiments, the battery cell further includes a separator. The present application does not particularly limit the type of the separator, and any well-known porous structure separator with good chemical stability and mechanical stability can be selected.

[0208] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0209] [Battery cell] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be made into an electrode assembly through a winding process or a stacking process.

[0210] In some embodiments, the positive current collector, the separator, the negative current collector, and the separator are stacked in sequence and wound together; after winding, the positive current collector's positive tab 111b is aligned and stacked, and the negative current collector's negative tab 112b is aligned and stacked, as Figure 6 shown.

[0211] In some embodiments, the battery cell further includes a top cover, and the top cover includes electrode terminals with opposite polarities for electrically connecting to the positive tab or the negative tab.

[0212] In some embodiments, as combined with Figure 6 shown, the battery cell 10 further includes a top cover 13, and the top cover 13 includes two electrode terminals 131 with opposite polarities, wherein one positive electrode terminal 131 is used for electrically connecting to the positive tab 111b, and the other negative electrode terminal 131 is used for electrically connecting to the negative tab 112b.

[0213] The wound positive tabs 111b are aligned and stacked, having a large connection area, so as to facilitate the direct electrical connection between the positive tabs 111b and the electrode terminals 131 without connecting the positive tabs 111b and the electrode terminals 131 through a connecting piece. Similarly, the wound negative tabs 112b are aligned and stacked, having a large connection area, so as to facilitate the direct electrical connection between the negative tabs 112b and the electrode terminals 131 without connecting the negative tabs 112b and the electrode terminals 131 through a connecting piece.

[0214] In a conventional battery, a connecting piece is required to connect the electrode terminal and the tab, but this will reduce the utilization rate of the electrode assembly and lower the battery energy density. When the above structure is adopted in the battery cell provided in the present application, canceling the setting of the connecting piece can effectively solve this problem, reduce the battery internal resistance, and further take into account improving the battery energy density and fast charging performance.

[0215] In some embodiments, the battery cell may include an outer package. The outer package can be used to encapsulate the above electrode assembly and electrolyte.

[0216] In some embodiments, the outer package of the battery cell can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package of the battery cell can also be a soft package, such as a pouch soft package. The material of the soft package can be plastic, and as plastics, polypropylene, polybutylene terephthalate, and polybutylene succinate can be listed, etc.

[0217] In some embodiments, as Figures 6 - 9 shown, the battery cell 10 further includes a housing 14, and the current collector 11 is disposed inside the housing 14.

[0218] In some embodiments, as Figures 6 - 9As shown, the housing 14 is square, and the thickness T of the housing is 30 mm to 55 mm, the width W is 150 mm to 250 mm, and the height H is 90 mm to 120 mm.

[0219] In some embodiments, the thickness T of the housing is 30 mm to 55 mm, such as 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, etc., or other unlisted values within the range of 30 mm to 55 mm.

[0220] In some embodiments, the width W of the housing is 150 mm to 250 mm, such as 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, 210 mm, 220 mm, 230 mm, 240 mm, 250 mm, etc., or other unlisted values within the range of 150 mm to 250 mm.

[0221] In some embodiments, the height H of the housing is 90 mm to 120 mm, such as 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, etc., or other unlisted values within the range of 90 mm to 120 mm.

[0222] In some embodiments, the charge time of the battery cell configured to charge from 10% SOC to 80% SOC at room temperature is 10 min to 17 min, such as 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, etc., or other unlisted values within the range of 10 min to 17 min.

[0223] The battery cell provided by the present application has excellent fast charging performance.

[0224] In some embodiments, the present application does not particularly limit the shape of the battery cell, which may be cylindrical, square or any other shape. For example, Figure 10 is a battery cell 5 with a square structure as an example. Optionally, the battery cell is a lithium-ion battery or a sodium-ion battery.

[0225] In some embodiments, referring to Figure 11, the outer package may include a housing 51 and a cover plate 53. Among them, the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose to form a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be disposed on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the separator can be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. The number of electrode assemblies 52 included in the battery cell 5 can be one or more, and those skilled in the art can select according to specific actual requirements.

[0226] In some embodiments, a battery device is provided. The battery device can be a battery module, a battery pack, an energy storage battery, etc. The above battery cells can be assembled into a battery module, and the number of battery cells included in the battery module can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery module.

[0227] Figure 12 is a battery module 4 as an example. Refer to Figure 12 , in the battery module 4, a plurality of battery cells 5 can be arranged in sequence along the length direction of the battery module 4. Of course, they can also be arranged in any other way. Further, the plurality of battery cells 5 can be fixed by fasteners.

[0228] Optionally, the battery module 4 may further include a housing having a receiving space, and a plurality of battery cells 5 are received in the receiving space.

[0229] In some embodiments, the above battery module can be further assembled into a battery pack, and the number of battery modules included in the battery pack can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery pack.

[0230] Figure 13 and Figure 14 is a battery pack 1 as an example. Refer to Figure 13 and Figure 14 , in the battery pack 1, it may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can be disposed on the lower box body 3 and form a closed space for receiving the battery module 4. The plurality of battery modules 4 can be arranged in the battery box in any way.

[0231] [Electrical device] In addition, the present application also provides an electrical device, which includes at least one of the battery cells, battery modules, or battery packs provided by the present application. The battery cell, battery module, or battery pack can be used as the power source of the electrical device or as the energy storage unit of the electrical device. The electrical device can include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, energy storage systems, etc., but is not limited thereto.

[0232] As the electrical device, the battery cell, battery module, or battery pack can be selected according to its usage requirements.

[0233] Figure 15 Take an electrical device as an example. The electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the electrical device for the battery cell, a battery pack or a battery module can be adopted.

[0234] In some embodiments, the electrical device includes a vehicle, and the length direction of the electrode assembly is placed along the traveling direction of the vehicle.

[0235] Another example of the device can be a mobile phone, a tablet computer, a laptop computer, etc. This device usually requires being thin and light, and a battery cell can be used as the power source.

[0236] Examples Hereinafter, examples of the present application will be described. The examples described below are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application. For those without specific techniques or conditions noted in the examples, the techniques or conditions described in the literature in the art or according to the product specifications are followed. Those reagents or instruments without the manufacturer noted are all conventional products that can be obtained through commercial purchase.

[0237] Example 1 1) Negative electrode plate Mix artificial graphite as the negative electrode active material, acetylene black as the conductive agent, styrene-butadiene rubber as the binder, and sodium carboxymethyl cellulose as the thickening agent in a mass ratio of 96:1:2:1, and then add deionized water as the solvent and stir to form a negative electrode paste. Coat the negative electrode paste evenly on the negative electrode current collector copper foil, and obtain the negative electrode plate after drying and cold pressing; wherein, the thickness of the negative electrode current collector copper foil is 4.5 μm, the single-sided areal density of the negative electrode plate is 0.155 g / 1540 mm 2 , and the tap density of the negative electrode plate is 1.47 g / cm 3, the size of the negative electrode film layer in the first direction is 92 mm; the volume particle size Dv50 of artificial graphite is 11 μm.

[0238] 2) Positive electrode sheet Mix the positive electrode active material lithium iron phosphate (LFP), binder polyvinylidene fluoride, and conductive agent acetylene black in a ratio of 97:2:1, and then add the solvent N-methylpyrrolidone (NMP) and stir to form a positive electrode paste; coat the positive electrode paste evenly on the positive electrode current collector aluminum foil, and after drying and cold pressing, obtain a positive electrode sheet. Among them, the thickness of the positive electrode current collector aluminum foil is 13 μm, and the single-sided areal density of the positive electrode sheet is 0.341 mg / 1540 mm 2 , the tap density of the positive electrode sheet is 2.51 g / cm 3 , the size of the positive electrode film layer in the first direction is 88.5 mm; the positive electrode active material includes first lithium-containing phosphate particles with a longest diameter of 0.3 μm - 1 μm and second lithium-containing phosphate particles with a longest diameter of 3 μm - 5 μm. In the longitudinal section of the positive electrode sheet, select any area that contains at least 100 olivine-structured lithium-containing phosphates. In the said any area, the number of first lithium-containing phosphate particles is greater than the number of second lithium-containing phosphate particles.

[0239] 3) Electrolyte Mix dimethyl carbonate (DMC), ethyl acetate (EA), ethylene carbonate (EC), and ethyl methyl carbonate (EMC) evenly in a mass ratio of 10:50:35:5 to obtain an electrolyte solvent. Include lithium hexafluorophosphate (LiPF 6 ) and lithium bis(fluorosulfonyl)imide (LiFSI) as lithium salts, and stir well until they are completely dissolved. Include vinylene carbonate (VC) with a mass percentage of 0.7% and fluoroethylene carbonate (FEC) with a mass percentage of 0.3% relative to the total mass of the electrolyte. Based on the total mass of the electrolyte, the mass ratio of lithium hexafluorophosphate (LiPF 6 ) is 8.9%; the mass ratio of lithium bis(fluorosulfonyl)imide LiFSI is 4.6%, and the lithium ion conductivity of the electrolyte is 14.5 mS / cm.

[0240] 4) Separator Use a commercially available polyethylene microporous film with a thickness of 7 μm and an average pore diameter of 80 nm as the separator.

[0241] 5) Battery cell The positive electrode tab and the negative electrode tab are cut. The distance between the center lines of two adjacent tabs on the positive electrode tab is 316 mm, and the distance between the center lines of two adjacent tabs on the negative electrode tab is 314 mm. The positive electrode tab, the separator, and the negative electrode tab are stacked and wound in sequence to obtain a wound electrode assembly, such that each layer of the positive electrode tab and the negative electrode tab in the electrode assembly has at least one tab. The electrode assembly is placed into a square aluminum outer package with a thickness of 50 mm, a width of 208 mm, and a height of 103 mm, and after drying, electrolyte is injected. Through processes such as encapsulation, standing, formation, aging, secondary encapsulation, and capacity measurement, a battery cell is obtained, and the tab of the battery cell is connected to the cover plate.

[0242] Examples 2 - 5 The battery cells of Examples 2 - 5 are basically similar to that of Example 1, except that the particle size Dv50 of the graphite is adjusted, as shown in Tables 1 - 4 specifically.

[0243] Examples 6 - 8 The battery cells of Examples 6 - 8 are basically similar to that of Example 1, except that the distance between adjacent tabs is changed, as shown in Tables 1 - 4 specifically.

[0244] Examples 9 - 12 The battery cells of Examples 9 - 12 are basically similar to that of Example 1, except that the types or contents of the organic solvent and lithium salt in the electrolyte are changed, as shown in Tables 1 - 4 specifically.

[0245] Example 13 The battery cell of Example 13 is basically similar to that of Example 1, except that the negative active material uses double - layer coating, and the method is as follows: artificial graphite with a particle size Dv50 of 13 μm is used as the lower layer, and artificial graphite with a particle size Dv50 of 10 μm is used as the upper layer, and they are uniformly coated on the negative current collector copper foil, and after drying and cold pressing, a negative electrode tab is obtained. As shown in Tables 1 - 4 specifically.

[0246] Examples 14 - 15 The battery cells of Examples 14 - 15 are basically similar to that of Example 1, except that the ratio of the single - side film layer thickness to the current collector thickness of the positive and negative electrodes is changed, as shown in Tables 1 - 4 specifically.

[0247] Comparative Examples 1 - 2 Comparative Examples 1 - 2 are basically similar to Example 1, except that the particle size Dv50 and specific surface area of the graphite are adjusted, as shown in Tables 1 - 4 specifically.

[0248] Comparative Examples 3 - 4 Comparative Examples 3 - 4 are basically similar to Example 1, except that the distance between adjacent tabs is changed. As shown in Tables 1 - 4 specifically.

[0249] I. Performance Test 1. DC internal resistance The DCR test of the DC internal resistance of a single battery cell can refer to the method in GB / T 31467 "Performance Test Specification for High-Power Lithium-Ion Power Batteries for HEV". For example, at room temperature, charge the single battery cell to 3.65V with a constant current of 0.33C, let it stand for 1 minute, then charge it to 3.65V with a constant current of 0.1C, let it stand for 30 minutes, discharge it to 2.0V with a constant current of 0.33C, record the discharge capacity A0 at this time, in units of Ah, and then charge it with a constant current of 0.33C for 0.5A0Ah to adjust the SOC to 50%. After leaving the single battery cell at 25°C for 2 hours, discharge it with a constant current of 3C for 10s, record ∆U discharge and ∆I discharge, and calculate the discharge DCR data of the lithium-ion battery through the following formula: R discharge = ∆U discharge / ∆I discharge, where ∆U discharge represents the voltage change within the first 10s of discharge, and ∆I discharge represents the current value within the first 10s of discharge.

[0250] 2. Charging time at 10% - 80% SOC Charging time test: ① Voltage calibration: 1) In the examples or comparative examples, the positive electrode sheet, negative electrode sheet, separator, and electrolyte are prepared into a laminated three-electrode battery and left to stand at 25 °C for 30 min; 2) At 25 °C, the battery monomer is charged to the charging cut-off voltage of 3.65 V at 0.33C, and then constant voltage charging is continued at this charging cut-off voltage until the current is 0.05C, and the charging is terminated (where C represents the rated capacity of the battery monomer); 3) Leave to stand at 25 °C for 1 h; 4) At 25 °C, discharge the battery monomer to the discharge cut-off voltage of 2.5 V at 0.33C, and record the total discharge capacity C0 discharged by the battery monomer; 5) Leave to stand at 25 °C for 1 h. ② Normal temperature charging test: 1) In the examples or comparative examples, the positive electrode sheet, negative electrode sheet, separator, and electrolyte are prepared into a laminated three-electrode battery and left to stand for 30 min; 2) DC discharge at 0.33C0 to the discharge cut-off voltage of 2.5 V, corresponding to 0% SOC at this time; 3) Leave to stand for 5 min; 4) Constant current charge at 5C0 until the negative electrode potential is 0 V, and read the capacity C1 at this time, corresponding to C1 / C0 SOC at this time; 5) Leave to stand for 5 min; 6) Constant current charge at 4.5C0 until the negative electrode potential is 0 V, and read the capacity C2 at this time, corresponding to C2 / C0 SOC at this time; 7) Leave to stand for 5 min; 8) Constant current charge at 4C0 until the negative electrode potential is 0 V, and read the capacity C3 at this time, corresponding to C3 / C0 SOC at this time; 9) Leave to stand for 5 min; 10) Constant current charge at 3C0 until the negative electrode potential is 0 V, and read the capacity C4 at this time, corresponding to C4 / C0 SOC at this time; 11) Leave to stand for 5 min; 12) Constant current charge at 2C0 until the negative electrode potential is 0 V, and read the capacity C5 at this time, corresponding to C5 / C0 SOC at this time; 13) Leave to stand for 5 min; 14) Constant current charge at 1C0 until the negative electrode potential is 0 V, and read the capacity C6 at this time, corresponding to C6 / C0 SOC at this time; 15) Leave to stand for 5 min; 16) Constant current charge at 0.8C0 until the negative electrode potential is 0 V, and read the capacity C7 at this time, corresponding to C7 / C0 SOC at this time; 17) Leave to stand for 5 min; 18) Constant current charge at 0.5C0 until the negative electrode potential is 0 V, and read the capacity C8 at this time, corresponding to C8 / C0 SOC at this time; 19) Leave to stand for 5 min; 20) Constant current charge at 0.33C0 until the negative electrode potential is 0 V, and read the capacity C9 (i.e., C0) at this time, corresponding to 100% SOC. The required charging time is obtained by summing up the total charging time during the charging process from 10% SOC to 80% SOC.

[0251] 3. Volume energy density At 25°C, the battery cell is discharged at a constant current of 0.33C to 2.5V, left standing for 5 minutes, charged at a constant current of 0.33C to the upper cut-off voltage of 3.65V, then charged at a constant voltage until the current reaches 0.05C, and left standing for 5 minutes; it is discharged at a constant current of 0.33C to the cut-off voltage of 2.5V, and the discharge capacity at this time is recorded to obtain the discharge energy E0. The volumetric energy density (Wh / L) = discharge energy E0 / cell volume (L).

[0252] 4. Cycling performance At 25°C, it is charged at a charging rate of 0.5C to 3.65V, then charged at a constant voltage of 3.65V until the current reaches 0.05C, left standing for 10 minutes, and then discharged at a discharging rate of 1C to 2.5V, left standing for 10 minutes. One such charge-discharge cycle is defined as one cycle, and the test is stopped until the battery capacity decays to 80% of the nominal capacity, denoted as the cycle number @80% SOH.

[0253] II. Analysis of test results of each example and comparative example Battery cells of each example and comparative example were prepared respectively according to the above method, and various performance parameters were measured. The results are shown in Tables 1 to 4 below.

[0254] Table 1 Preparation parameters of the negative electrode sheet

[0255] Table 2 Preparation parameters of the positive electrode sheet and electrolyte

[0256] Table 3 Preparation parameters of the electrolyte

[0257] Table 4 Battery performance parameters

[0258] Among the battery cells of Examples 1 to 15, a lithium-containing phosphate containing an olivine structure was used as the positive electrode active material in the positive electrode film layer; graphite with an average particle size Dv50 of 8 μm to 15 μm was used as the negative electrode active material in the negative electrode film layer; and as Figure 5 shown, the negative electrode current collector includes at least two negative electrode tabs, and the distance between the center lines of two adjacent negative electrode tabs is 10 mm to 350 mm; therefore, the battery cells prepared in Examples 1 to 15 all have excellent fast charging performance, energy density, cycling performance, and low DC internal resistance.

[0259] In Comparative Examples 1 to 2, the average particle size Dv50 of graphite in the negative electrode film layer exceeded the range of 8 μm to 15 μm, where: the Dv50 of graphite in Comparative Example 1 was too large, while the Dv50 of graphite in Comparative Example 2 was too small.

[0260] From the comparison between Comparative Examples 1-2 and Examples 1-15, it can be seen that when the average particle size Dv50 of graphite is greater than 15 μm, the fast charging performance and DC internal resistance of the battery cell cannot be effectively improved; while when the average particle size Dv50 of graphite is less than 8 μm, the cycle performance of the battery cell cannot be effectively improved. Therefore, when the average particle size Dv50 of graphite in the negative electrode film layer is in the range of 8 μm to 15 μm, the cycle performance, fast charging performance and DC internal resistance of the battery can be improved simultaneously. When it exceeds this range, the comprehensive performance of the battery is poor.

[0261] In the negative electrode current collectors of Comparative Examples 3-4, the distance between the center lines of any two adjacent negative electrode tabs exceeds the range of 10 mm to 350 mm.

[0262] From the comparison between Comparative Examples 3-4 and Examples 1-15, it can be seen that when the distance between the center lines of the two negative electrode tabs exceeds the range of 10 mm to 350 mm, the cycle performance, fast charging performance and DC internal resistance of the battery cannot be effectively improved simultaneously, and the comprehensive performance of the battery is poor. At the same time, as the exceeded range increases, the cycle performance, fast charging performance and DC internal resistance of the battery deteriorate further, and the comprehensive performance of the battery decreases further. Therefore, when the distance between the center lines of the two negative electrode tabs is in the range of 10 mm to 350 mm, the cycle performance, fast charging performance and DC internal resistance of the battery can be improved simultaneously. When it exceeds this range, the comprehensive performance of the battery is poor.

[0263] In Examples 1-5, the average particle size Dv50 of graphite in the negative electrode film layer is in the range of 8 μm to 15 μm, and the battery cells prepared therefrom can simultaneously have excellent energy density, fast charging performance, cycle performance, and low DC internal resistance. In addition, the results also show that when the Dv50 of graphite gradually increases in the range of 8 μm to 15 μm, the cycle performance of the battery is improved to a certain extent, but the fast charging performance decreases to a certain extent and the DC internal resistance increases to a certain extent; while when the Dv50 of graphite gradually decreases in the range of 8 μm to 15 μm, the fast charging performance of the battery is improved to a certain extent, the DC internal resistance decreases to a certain extent, but the cycle performance decreases to a certain extent. Therefore, only when the Dv50 of graphite in the negative electrode film layer is in the range of 8 μm to 15 μm can the fast charging performance, cycle performance and DC internal resistance of the battery be improved simultaneously. When the Dv50 of graphite is in the range of 9.5 μm to 11.5 μm, the comprehensive performance of the battery is better. When the Dv50 of graphite is too low, the energy density of the battery decreases.

[0264] In Examples 1, 6 to 8, the distance between the centerlines of any two adjacent negative electrode tabs is 10 mm to 350 mm, and the distance between the centerlines of any two adjacent positive electrode tabs is 10 mm to 350 mm. The prepared battery cells can take into account excellent fast charging performance, cycle performance, and low DC internal resistance. At the same time, the results also show that when the distance between the centerlines of any two adjacent tabs gradually decreases within the range of 10 mm to 350 mm, the fast charging performance and DC internal resistance of the battery are further improved, making the comprehensive performance of the battery better.

[0265] In Examples 1, 9 to 12, the electrolyte uses the following formula. The prepared battery cells can take into account excellent energy density, fast charging performance, cycle performance, and low DC internal resistance: The organic solvent uses linear carboxylic esters (such as ethyl acetate) with a mass ratio of 40% to 75%, linear carbonates (such as DMC, EMC) with a mass ratio of 10% to 40%, and cyclic carbonates (such as ethylene carbonate), where the mass ratio of dimethyl carbonate is 5% to 15%, and the mass ratio of linear carboxylic esters (such as ethyl acetate) to dimethyl carbonate is 2.0 to 7.0; The lithium salt uses LiPF 6 and LiFSI, and the mass ratio of LiPF 6 and LiFSI is 1.2:1 to 2:1.

[0266] At the same time, comparing Examples 1, 9, and 10 shows that: as the proportion of linear carboxylic esters (such as ethyl acetate) and LiFSI added to the electrolyte gradually increases, the fast charging performance and DC internal resistance of the battery are further improved; while as the proportion of linear carbonates (such as DMC) and LiPF 6 added to the electrolyte gradually increases, the cycle performance of the battery is further improved.

[0267] At the same time, comparing Examples 1, 11, and 12 shows that: when only linear carboxylic esters (such as ethyl acetate) exist in the organic solvent of the electrolyte and no carbonates exist, and only LiFSI exists in the lithium salt and no LiPF 6 exists, the fast charging performance and DC internal resistance of the battery are further improved, but the cycle performance of the battery is poor; when only linear carbonates (such as DMC) exist in the organic solvent of the electrolyte and no linear carboxylic esters exist, and only LiPF 6 exists and no LiFSI exists, the cycle performance of the battery is further improved, but the improvement of the fast charging performance and DC internal resistance is limited. Therefore, when linear carbonates and linear carboxylic esters with the above mass ratios are used as organic solvents in the electrolyte at the same time, and LiPF 6When using LiFSI as the lithium salt, by combining various solvents and lithium salts with each other, it is possible to further balance and improve the fast charging performance, DC internal resistance, and cycling performance of the battery, making the comprehensive performance of the battery better.

[0268] In Examples 1 and 13, the negative electrode film layer contains at least one layer of graphite as the negative electrode active material, and its average particle size Dv50 is in the range of 8 μm to 15 μm. The battery monomers prepared therefrom can balance excellent energy density, fast charging performance, cycling performance, and low DC internal resistance. In addition, from the comparison between Example 1 and Example 13, it can be seen that when the negative electrode film layer includes two layers of artificial graphite with different particle sizes as the negative electrode active material layers (the first negative electrode active material layer is disposed on the surface of the negative electrode current collector, the second negative electrode active material layer is disposed on the side of the first negative electrode active material layer away from the negative electrode current collector, and the Dv50 of the first negative electrode active material layer is greater than that of the second negative electrode active material layer), it is possible to further balance and improve the fast charging performance and DC internal resistance of the battery, making the comprehensive performance of the battery better.

[0269] In Examples 1 and 14 - 15, the ratio of the single - side thickness of the negative electrode film layer to the thickness of the negative electrode current collector is 12 to 20. The battery monomers prepared therefrom can balance excellent energy density, fast charging performance, cycling performance, and low DC internal resistance. In addition, the results also show that when the ratio of the single - side thickness of the negative electrode film layer to the thickness of the negative electrode current collector gradually increases within the above range, the energy density of the battery can be further improved; when the ratio of the single - side thickness of the negative electrode film layer to the thickness of the negative electrode current collector gradually decreases within the above range, the fast charging performance, DC internal resistance, and cycling performance of the battery can be further improved.

[0270] In Examples 1 - 15, as Figure 4 shown, in the cross - section of the positive electrode film layer along the thickness direction, the lithium - containing phosphates in the positive electrode film layer all contain first lithium - containing phosphate particles with the longest diameter ranging from 0.05 μm to 0.3 μm and second lithium - containing phosphate particles with the longest diameter ranging from 1 μm to 3 μm. The battery monomers prepared therefrom can balance excellent energy density, fast charging performance, cycling performance, and low DC internal resistance.

[0271] In Examples 1 - 15, the compaction density of the positive electrode plate is 2.3 g / cm 3 to 2.6 g / cm 3 , and the compaction density of the negative electrode plate is 1.3 g / cm 3 to 1.6 g / cm 3 . The battery monomers prepared therefrom can balance excellent energy density, fast charging performance, cycling performance, and low DC internal resistance.

[0272] 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 constitution 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 constituent elements in the embodiments are also included in the scope of this application.

Claims

1. A battery cell, comprising a positive electrode sheet, a negative electrode sheet and a separator between the positive electrode sheet and the negative electrode sheet, characterized in that: The positive electrode plate comprises a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material, and the positive electrode active material comprises a lithium-containing phosphate with an olivine structure; The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, the negative electrode film layer includes a negative electrode active material, the average particle size Dv50 of the negative electrode active material is 8 μm to 15 μm, and the negative electrode active material includes graphite; The negative electrode current collector includes a negative electrode current collecting portion and at least two negative electrode tabs arranged on the same side of the negative electrode current collecting portion, the negative electrode tabs extend from the negative electrode current collecting portion along a first direction, wherein a distance between center lines of two adjacent negative electrode tabs is 10 mm to 350 mm, and the center line is parallel to the first direction.

2. The battery cell according to claim 1, characterized in that: The positive electrode current collector includes a positive electrode current collecting portion and at least two positive electrode tabs arranged on the same side of the positive electrode current collecting portion, the positive electrode tabs extend from the positive electrode current collecting portion along a first direction, wherein the distance between the center lines of two adjacent positive electrode tabs is 10 mm to 350 mm, and the center line is parallel to the first direction.

3. The battery cell according to claim 1, characterized in that: The distance between the center lines of two adjacent negative electrode ears is 20 mm to 330 mm.

4. The battery cell according to claim 2, characterized in that: The distance between the center lines of two adjacent positive electrode ears is 20 mm to 330 mm.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The average particle size Dv50 of the negative electrode active material is 9.5 μm to 11.5 μm.

6. The battery cell according to claim 1, characterized in that: The battery cell includes an electrolyte, the electrolyte includes an organic solvent, and the organic solvent includes a carboxylate solvent and a carbonate solvent.

7. The battery cell according to claim 6, characterized in that: The organic solvent includes a linear carboxylic acid ester, and the mass proportion of the linear carboxylic acid ester is 40% to 75% based on the total mass of the electrolyte.

8. The battery cell according to claim 7, characterized in that: The linear carboxylic acid ester has a general structural formula of R1-COO-R2, wherein R1 and R2 each independently include one or more of a C1-C5 alkyl group and a C1-C5 halogenated alkyl group.

9. The battery cell according to claim 8, characterized in that: The linear carboxylic acid ester includes one or more of ethyl acetate, methyl acetate, methyl propionate, propyl acetate, ethyl formate, and isopropyl formate.

10. The battery cell according to claim 6, characterized in that: The organic solvent includes a carbonate solvent, and the carbonate solvent includes a linear carbonate and a cyclic carbonate. Based on the total mass of the electrolyte, the mass proportion of the linear carbonate is 10% to 40%.

11. The battery cell according to claim 10, characterized in that: The cyclic carbonate includes one or more of ethylene carbonate and propylene carbonate, and the linear carbonate includes one or more of dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

12. The battery cell according to claim 11, characterized in that: The linear carbonate includes dimethyl carbonate, and based on the total mass of the electrolyte, the mass proportion of the dimethyl carbonate is 5% to 15%.

13. The battery cell according to claim 6, characterized in that: The electrolyte includes dimethyl carbonate and linear carboxylic acid ester, and the mass ratio of the linear carboxylic acid ester to the dimethyl carbonate is 2.0 to 7.

0.

14. The battery cell according to claim 13, characterized in that: The mass ratio of the linear carboxylic acid ester to the dimethyl carbonate is 3.0 to 6.

0.

15. The battery cell according to claim 6, characterized in that: The electrolyte includes a lithium salt, and the mass proportion of the lithium salt is 13% to 20% based on the total mass of the electrolyte.

16. The battery cell according to claim 15, characterized in that: The lithium salt includes at least two of lithium hexafluorophosphate and fluorine-containing sulfonyl imide salts, and the fluorine-containing sulfonyl imide salt includes one or more of lithium bis(fluorosulfonyl)imide LiFSI and lithium bis(trifluoromethanesulfonyl)imide LiTFSI.

17. The battery cell according to claim 15, characterized in that: The lithium salt includes lithium hexafluorophosphate LiPF6 and lithium bis(fluorosulfonyl)imide LiFSI.

18. The battery cell according to claim 17, characterized in that: In the electrolyte, the mass ratio of lithium hexafluorophosphate LiPF6 to lithium bis(fluorosulfonyl)imide LiFSI is 1.2:1 to 2:

1.

19. The battery cell according to claim 6, characterized in that: The electrolyte further comprises an additive, and the additive comprises a carbonate additive.

20. The battery cell according to claim 19, characterized in that: Based on the total mass of the electrolyte, the mass proportion of the carbonate additive in the electrolyte is 0.5% to 7%.

21. The battery cell according to claim 19 or 20, characterized in that: The carbonate additives include vinylene carbonate VC and fluoroethylene carbonate FEC.

22. The battery cell according to claim 19 or 20, characterized in that: The additive includes vinylene carbonate VC; based on the total mass of the electrolyte, the mass proportion of vinylene carbonate VC in the electrolyte is 0.5% to 2%.

23. The battery cell according to claim 19 or 20, characterized in that: The additive includes fluoroethylene carbonate (FEC); based on the total mass of the electrolyte, the mass proportion of fluoroethylene carbonate (FEC) in the electrolyte is 0.1% to 1%.

24. The battery cell according to claim 1, characterized in that The general composition formula of the lithium-containing phosphate with an olivine structure is as shown in Formula I: Li x A y Me a M b P 1-c X c Y z Formula I Among them, 0.1≤x≤1.3, 0≤y≤1.3, and 0.9≤x+y≤1.3; 0.9≤a≤1.5, 0≤b≤0.5, and 0.9≤a+b≤1.5; 0≤c≤0.5; 3≤z≤5; A includes one or more of Na, K, and Mg; Me includes one or more of Mn, Fe, Co, and Ni; M includes one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; X includes one or more of S, Si, Cl, B, C, and N; Y includes one or more of O and F.

25. The battery cell according to claim 24, characterized in that: M includes one or more of Al, Ti, V, and Mg.

26. The battery cell according to claim 24 or 25, characterized in that: The positive electrode active material satisfies at least one of the following conditions: (1) The positive electrode active material contains Al element, the mass content of which is 0.01-0.05%, based on the total mass of the positive electrode active material; (2) The positive electrode active material contains Ti element, the mass content of which is 0.01-0.03%, based on the total mass of the positive electrode active material; (3) The positive electrode active material contains V element, the mass content of which is 0.1-0.3%, based on the total mass of the positive electrode active material; (4) The positive electrode active material contains Mg element, with a mass content of 0.001-0.01% based on the total mass of the positive electrode active material.

27. The battery cell according to claim 1, characterized in that: In a cross section of the positive electrode film layer along the thickness direction, the olivine-structured lithium-containing phosphate includes first lithium-containing phosphate particles with a longest diameter of 0.05 μm to 0.3 μm and second lithium-containing phosphate particles with a longest diameter of 1 μm to 3 μm.

28. The battery cell according to claim 27, characterized in that: In a cross section of the positive electrode film layer along the thickness direction, the number of the first lithium-containing phosphate particles is greater than the number of the second lithium-containing phosphate particles.

29. The battery cell according to claim 1, characterized in that: The size of the positive electrode film layer along the first direction is W1 mm, and the size of the negative electrode film layer along the first direction is W2 mm, wherein W2>W1, and the difference between W2 and W1 is 3 mm to 5 mm.

30. The battery cell according to claim 1, characterized in that The compaction density of the positive electrode sheet is 2.3 g / cm 3 Up to 2.6g / cm 3 .

31. The battery cell according to claim 1, characterized in that The compaction density of the positive electrode sheet is 2.4 g / cm 3 Up to 2.55g / cm 3 .

32. The battery cell according to claim 1, characterized in that The single-sided coating density of the positive electrode sheet is 0.33g / 1540.25mm 2 Up to 0.4 g / 1540.25 mm 2 .

33. The battery cell according to claim 1, characterized in that: The single-sided coating density of the positive electrode sheet is 0.335 g / 1540.25 mm 2 Up to 0.38 g / 1540.25 mm 2 .

34. The battery cell according to claim 1, characterized in that The compaction density of the negative electrode sheet is 1.3 g / cm 3 Up to 1.6g / cm 3 .

35. The battery cell according to claim 1, characterized in that The compaction density of the negative electrode sheet is 1.35 g / cm 3 Up to 1.55g / cm 3 .

36. The battery cell according to claim 1, characterized in that The single-sided coating density of the negative electrode plate is 0.15 g / 1540.25 mm 2 Up to 0.19 g / 1540.25 mm 2 .

37. The battery cell according to claim 1, characterized in that The single-sided coating density of the negative electrode plate is 0.15 g / 1540.25 mm 2 Up to 0.165 g / 1540.25 mm 2 .

38. The battery cell according to claim 1, characterized in that The thickness of the negative electrode current collector is 4-6 μm.

39. The battery cell according to claim 1, characterized in that: The ratio of the single-side thickness of the negative electrode film layer to the thickness of the negative electrode current collector is 12 to 20.

40. The battery cell according to claim 1, characterized in that The ratio of the single-side thickness of the negative electrode film layer to the thickness of the negative electrode current collector is 13 to 20.

41. The battery cell according to claim 1, characterized in that The negative electrode film layer includes a first negative electrode active material layer arranged on the surface of the negative electrode collector and a second negative electrode active material layer arranged on the side of the first negative electrode active material layer away from the negative electrode collector, the negative electrode active material in the first negative electrode active material layer includes a first artificial graphite, the negative electrode active material in the second negative electrode active material layer includes a second artificial graphite, and the average particle size Dv50 of the first artificial graphite is greater than the average particle size Dv50 of the second artificial graphite.

42. The battery cell according to claim 41, characterized in that The average particle size Dv50 of the first artificial graphite is 11 μm to 15 μm.

43. The battery cell according to claim 41, characterized in that The average particle size Dv50 of the second artificial graphite is 8 μm to 15 μm.

44. The battery cell according to claim 41, characterized in that The average particle size Dv50 of the second artificial graphite is 9.5 μm to 11.5 μm.

45. The battery cell according to claim 1, characterized in that The positive current collector includes a positive current collecting portion and at least two positive electrode tabs arranged on the same side of the positive current collecting portion; the battery cell also includes a top cover, the top cover includes a positive electrode terminal and a negative electrode terminal with opposite polarities, and the positive electrode terminal and the negative electrode terminal are respectively used to be electrically connected to the positive electrode tab or the negative electrode tab.

46. ​​The battery cell according to claim 1, characterized in that The battery cell further includes a shell, which is square in shape, has a thickness of 30 mm to 55 mm, a width of 150 mm to 250 mm, and a height of 90 mm to 120 mm.

47. The battery cell according to claim 1, characterized in that The battery cell is configured to be charged from 10% SOC to 80% SOC in a charging time of 10 to 17 minutes at room temperature.

48. A battery device, characterized in that: Comprising the battery monomer described in any one of claims 1 to 47, the battery device is at least one of a battery module, a battery pack, and an energy storage device.

49. An electrical device, characterized in that: A battery cell comprising any one of claims 1 to 47 or a battery device according to claim 48.

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