Battery cell, battery apparatus and electrical apparatus

Abstract

A battery cell (5), a battery apparatus and an electrical apparatus. In the battery cell (5), a positive electrode active material comprises lithium-containing phosphate having an olivine structure; the average particle size Dv50 of a negative electrode active material is 8 um to 15 um, and the negative electrode active material comprises graphite; a negative electrode current collector comprises a negative electrode current collecting portion (112a) and at least two negative electrode tabs provided on the same side of the negative electrode current collecting portion (112a), the negative electrode tabs extending from the negative electrode current collecting portion (112a) in a first direction (F1), the distance between the center lines (L) of any two adjacent negative electrode tabs being 10 mm to 350 mm, and the center line (L) being parallel to the first direction (F1).

Description

Battery cell, battery device and electric device TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery cell, a battery device and an electric device. BACKGROUND

[0002] In recent years, batteries are widely used in energy storage power systems such as hydroelectric, thermal, wind and solar power stations, and in many fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. With the popularization of battery applications, higher requirements are put forward for its energy density, fast charging performance, cycle performance, service life, safety performance, etc.

[0003] SUMMARY

[0004] The present application aims to provide a new type of battery cell which has excellent fast charging performance and can also have high energy density, good cycle performance and low direct current internal resistance.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a battery cell, comprising a positive electrode sheet, a negative electrode sheet and a separator film between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, the positive electrode film layer comprising a positive electrode active material, the positive electrode active material comprising lithium-containing phosphate with olivine structure; the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector, the negative electrode film layer comprising a negative electrode active material, the average particle size Dv50 of the negative electrode active material being 8-15 μm, the negative electrode active material comprising graphite; the negative electrode current collector comprises a negative electrode current collecting part and at least two negative electrode tabs provided on the same side of the negative electrode current collecting part, the negative electrode tabs extending out from the negative electrode current collecting part along a first direction, wherein the distance between the center lines of two adjacent negative electrode tabs is 10-350 mm, and the center lines are parallel to the first direction.

[0006] The application improves the transmission path of lithium ions in the negative active material during charging by using small particle size negative active material, which is beneficial to improve the fast charging capacity of the battery monomer. However, when the fast charging capacity of the battery monomer is improved, the corresponding charging current it can withstand is also improved. At this time, if the negative tab structure is not reasonably arranged, it will cause the internal heat of the battery monomer to gather during fast charging, the internal temperature of the battery rises, and the electrolyte gas is generated, the impedance of the solid electrolyte interface film (SEI film) of the negative electrode increases and other adverse reactions, thereby increasing the internal resistance of the battery and affecting the performance of the battery monomer. The application effectively reduces the heat accumulation in the battery monomer when the fast charging capacity is improved, reduces the internal temperature rise, and inhibits the growth of the direct current resistance (DCR) of the battery monomer. In any embodiment, the positive current collector includes a positive current collecting part and at least two positive tabs arranged on the same side of the positive current collecting part, the positive tabs extend from the positive current collecting part along a first direction, wherein the distance between the center lines of the two adjacent positive tabs is 10mm to 350mm, and the center line is parallel to the first direction.

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

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

[0009] When the positive and negative current collectors respectively include at least two tabs with the above structural characteristics in the battery monomer provided by the application, the direct current resistance of the battery monomer can be further improved, thereby further reducing the heat generation of the battery, and the battery has better safety performance.

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

[0011] When the particle size of the negative active material (such as graphite) is in the above range, the fast charging performance and direct current resistance of the battery can be further improved, and the battery has good cycle performance at the same time.

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

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

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

[0015] In any embodiment, the linear carboxylic acid ester has a general structure of R1-COO-R2, where R1 and R2 each independently comprises one or more of C1-C5 alkyl and C1-C5 haloalkyl.

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

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

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

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

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

[0021] When the carbonic acid ester of the above type and mass percentage is used as the organic solvent in the electrolyte, the side reactions and the degree of gas generation of the battery during the cycle process can be improved, thereby allowing the battery to have both good cycle performance.

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

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

[0024] When the dimethyl carbonate and the linear carboxylic acid ester of the above mass ratio are used as the organic solvent in the electrolyte, the combination of the two solvents can further improve the fast-charging performance and the cycle performance of the battery.

[0025] In any embodiment, the electrolyte comprises a lithium salt, and the mass percentage of the lithium salt is 13-20% based on the total mass of the electrolyte.

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

[0027] Lithium hexafluorophosphate is less likely to produce gas during the cycle process, which can further improve the cycle performance of the battery; and the dissociation ability of fluorosulfonylimide salt is strong, which can further improve the fast-charging performance of the battery.

[0028] In any embodiment, the lithium salt comprises lithium hexafluorophosphate LiPF6 and lithium bisfluorosulfonylimide LiFSI.

[0029] In any embodiment, the mass ratio of lithium hexafluorophosphate LiPF6 to lithium bisfluorosulfonylimide LiFSI in the electrolyte is 1.2:1-2:1.

[0030] When lithium hexafluorophosphate and lithium bisfluorosulfonylimide in the above mass ratio range are used in the electrolyte at the same time, the fast-charging performance and cycle performance of the battery can be further improved.

[0031] In any embodiment, the electrolyte further comprises an additive, and the additive comprises a carbonate-based additive.

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

[0033] In any embodiment, the carbonate-based additive comprises vinylene carbonate VC and fluoroethylene carbonate FEC.

[0034] In the battery provided in the present application, the carbonate-based additive, such as fluoroethylene carbonate and vinylene carbonate, in the above mass percentage range is further added to the electrolyte, which can form an SEI film on the negative electrode surface, thereby reducing the side reaction between the electrode and the electrolyte, and further making the battery have good cycle performance.

[0035] In any embodiment, the additive comprises vinylene carbonate VC, and the mass percentage of the vinylene carbonate VC in the electrolyte is 0.5-2% based on the total mass of the electrolyte.

[0036] When the vinylene carbonate in the above mass percentage range is added to the electrolyte as an additive, the SEI film formed thereby is more stable, which is conducive to further improving the cycle performance of the battery.

[0037] In any embodiment, the additive comprises fluoroethylene carbonate FEC, and the mass fraction of the fluoroethylene carbonate FEC in the electrolyte is 0.1% to 1% based on the total mass of the electrolyte.

[0038] When the fluoroethylene carbonate in the above mass fraction range is added as an additive in the electrolyte, the formed SEI film has low impedance, and the fast charging performance of the battery can be further improved.

[0039] In any embodiment, the lithium-containing phosphate with olivine structure has a general formula as shown in Formula I,

[0040] Li x A y Me a M b P 1-c X c Y z Formula I,

[0041] 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 comprises one or more of Na, K, Mg; Me comprises one or more of Mn, Fe, Co, Ni; M comprises 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, Ce; X comprises one or more of S, Si, Cl, B, C, N; Y comprises one or more of O, F.

[0042] 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.

[0043] In any embodiment, M comprises one or more of Al, Ti, V, Mg.

[0044] In any embodiment, the positive electrode active material satisfies at least one of the following conditions:

[0045] (1) the positive electrode active material contains Al element, and the mass content is 0.01-0.05%, based on the total mass of the positive electrode active material;

[0046] (2) the positive electrode active material contains Ti element, and the mass content is 0.01-0.03%, based on the total mass of the positive electrode active material;

[0047] (3) the positive electrode active material contains V element, the mass content is 0.1-0.3%, based on the total mass of the positive electrode active material;

[0048] (4) the positive electrode active material contains Mg element, the mass content is 0.001-0.01%, based on the total mass of the positive electrode active material.

[0049] When the lithium-containing phosphate as the positive electrode active material contains Al, Ti, V and other elements, the specific capacity can be further improved.

[0050] In any embodiment, in the 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 0.05-0.3 μm and second lithium-containing phosphate particles with a longest diameter of 1-3 μm.

[0051] In the battery cell provided by the application, when the positive electrode active material contains lithium-containing phosphate particles with a longest diameter of 0.05-0.3 μm, the direct current internal resistance of the battery cell can be further improved, thereby further reducing the heat generation of the battery, and the battery has excellent safety performance.

[0052] In the battery cell provided by the application, when the lithium-containing phosphate as the positive electrode active material contains both first lithium-containing phosphate particles with a longest diameter of 0.05-0.3 μm and second lithium-containing phosphate particles with a longest diameter of 1-3 μm, the compaction density of the electrode sheet can be effectively improved by the size grading of the particles, thereby making the battery cell also have a high energy density.

[0053] 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.

[0054] When the number of the first lithium-containing phosphate particles with a longest diameter of 0.05-0.3 μm is greater than the number of the second lithium-containing phosphate particles with a longest diameter of 1-3 μm in the lithium-containing phosphate as the positive electrode active material, the direct current internal resistance and the fast charging performance of the battery can be further improved.

[0055] In any embodiment, the dimension of the positive electrode film layer along the first direction is W1 mm, and the dimension of the negative electrode film layer along the negative electrode sheet width direction is W2 mm, wherein W2>W1, and the difference between W2 and W1 is 3-5 mm.

[0056] Lithium ions that cannot be timely embedded in the negative electrode during the cycling process can 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 W2 of the negative electrode film layer and the size W1 of the positive electrode film layer have the above relationship, the formation of lithium dendrites on the surface of the negative electrode can be improved, so that the battery has both good cycling performance and good energy density.

[0057] In any embodiment, the compaction density of the positive electrode sheet is 2.3 g / cm 3 to 2.6 g / cm 3 .

[0058] In any embodiment, the compaction density of the positive electrode sheet is 2.4 g / cm 3 to 2.55 g / cm 3 .

[0059] When the compaction density of the positive electrode sheet is in 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 area density of the positive electrode sheet is 0.33 g / 15 40.25 mm 2 to 0.4 g / 15 40.25 mm 2 .

[0061] In any embodiment, the single-sided coating area density of the positive electrode sheet is 0.335 g / 15 40.25 mm 2 to 0.38 g / 15 40.25 mm 2 .

[0062] In the battery cell provided in the present application, when the coating area density of the positive electrode film layer is in 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 compaction density of the negative electrode sheet is 1.3 g / cm 3 to 1.6 g / cm 3 .

[0064] In any embodiment, the compaction density of the negative electrode sheet is 1.35 g / cm 3 to 1.55 g / cm 3 .

[0065] When the compaction density of the negative electrode sheet is in the above range, the energy density of the battery can be further improved while ensuring the kinetic performance.

[0066] In any embodiment, the single-sided coating area density of the negative electrode tab is 0.15 g / 15 40.25 mm 2 to 0.19 g / 15 40.25 mm 2 .

[0067] In any embodiment, the single-sided coating area density of the negative electrode tab is 0.15 g / 15 40.25 mm 2 to 0.165 g / 15 40.25 mm 2 .

[0068] In the battery cell provided by the present application, when the coating area 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.

[0069] In any embodiment, the thickness of the negative electrode current collector is 4-6 μm.

[0070] 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 12-20.

[0071] 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 13-20.

[0072] 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 energy density and the fast charging performance of the battery can be further improved.

[0073] In any embodiment, the negative electrode film layer comprises a first negative electrode active material layer arranged on the surface of the negative electrode current 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 current collector, the negative electrode active material in the first negative electrode active material layer comprises a first artificial graphite, the negative electrode active material in the second negative electrode active material layer comprises 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.

[0074] In any embodiment, the average particle size Dv50 of the first artificial graphite is 11-15 μm.

[0075] In any embodiment, the average particle size Dv50 of the second artificial graphite is 8-15 μm.

[0076] In any embodiment, the average particle size Dv50 of the second artificial graphite is 9.5-11.5 μm.

[0077] The battery cell provided in the application can further improve the kinetic performance of the battery when the double-layer coating scheme is used in the negative electrode film layer.

[0078] In any embodiment, the battery cell further comprises a top cover comprising a positive electrode terminal and a negative electrode terminal with opposite polarities, which are respectively used to be electrically connected with the positive electrode tab or the negative electrode tab.

[0079] In a conventional battery, a jumper is needed to connect the electrode terminal and the tab, which will cause the utilization rate of the electrode assembly to be lost and the energy density of the battery to be reduced. When the structure described above is used in the battery cell provided in the application, the jumper can be cancelled, which can effectively solve this problem, reduce the internal resistance of the battery, and further improve the energy density and fast charging performance of the battery.

[0080] In any embodiment, the battery cell further comprises a shell, which is square-shaped, has a thickness of 30-55 mm, a width of 150-250 mm, and a height of 90-120 mm.

[0081] In any embodiment, the battery cell is configured to have a charging time of 10-17 min for charging from 10% SOC to 80% SOC at room temperature.

[0082] The battery cell provided in the application has excellent fast charging performance.

[0083] The second aspect of the application also provides a battery device, which comprises the battery cell of the first aspect of the application and is at least one of a battery module, a battery pack, and an energy storage device.

[0084] The third aspect of the application also provides a power utilization device, which comprises the battery cell of the first aspect of the application or the battery device of the second aspect of the application. BRIEF DESCRIPTION OF DRAWINGS

[0085] FIG. 1 is a schematic diagram of the size of the electrode film layer in an embodiment of the application;

[0086] FIG. 2 is a schematic diagram of the size of the electrode film layer in an embodiment of the application;

[0087] FIG. 3 is a schematic diagram of the size of the electrode film layer in an embodiment of the application;

[0088] FIG. 4 is an electron microscope observation result of the longitudinal section of the positive electrode tab in an embodiment of the application;

[0089] FIG. 5 is a schematic diagram of the electrode tab in an embodiment of the application;

[0090] FIG. 6 is an exploded view of the battery cell in an embodiment of the application;

[0091] FIG. 7 is a schematic view of a battery cell according to an embodiment of the present application;

[0092] FIG. 8 is a schematic view of a battery cell according to an embodiment of the present application;

[0093] FIG. 9 is a schematic view of a battery cell according to an embodiment of the present application;

[0094] FIG. 10 is a schematic view of a battery cell according to an embodiment of the present application;

[0095] FIG. 11 is an exploded view of the battery cell according to an embodiment of the present application shown in FIG. 10;

[0096] FIG. 12 is a schematic view of a battery module according to an embodiment of the present application;

[0097] FIG. 13 is a schematic view of a battery pack according to an embodiment of the present application;

[0098] FIG. 14 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 13;

[0099] FIG. 15 is a schematic view of an electric device using the battery cell according to an embodiment of the present application as a power source.

[0100] Explanation of Reference Numerals:

[0101] 1 battery pack; 2 upper case; 3 lower case; 4 battery module; 5 battery cell; 51 case; 52 electrode assembly; 53 top cover assembly; 10 battery cell; 11 current collector; 11a current collecting portion; 111a positive electrode current collecting portion; 112a negative electrode current collecting portion; 11b tab; 111b positive electrode tab; 112b negative electrode tab; F1 first direction; W1 dimension of positive electrode film layer in first direction; W2 dimension of negative electrode film layer in first direction; L center line; 13 top cover; 131 electrode terminal; 14 case. DETAILED DESCRIPTION

[0102] Hereinafter, embodiments of the battery cell and electric device according to the present application are specifically disclosed while appropriately referring to the accompanying drawings. However, there are cases where unnecessary detailed explanations are omitted. For example, there are cases where detailed explanations of matters that are already well known, repeated explanations of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided so that those skilled in the art can fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0103] The ranges disclosed herein are intended to be "open" ranges, i.e., the upper and lower limits of the range are not included. The ranges are also intended to include any and all sub-ranges of the range, i.e., all combinations of any two of the range limits, unless otherwise indicated. For example, a range of "1 to 10" is intended to include any number from 1 to 10, including the integers 1 and 10. Unless otherwise indicated, the use of "or" in the disclosed aspects herein is the inclusive, and not the exclusive use. Only the context, and not the number of times an item is used, can determine that it is the exclusive use. For example, the phrase "A or B" is intended to mean "A or B or both A and B." As used herein, the term "about" means that the recited numerical property or value is within 10% of the recited value, unless otherwise indicated. For example, "about 5" means that the value is within 0.5 of 5. As used herein, the term "substantially" means that the recited numerical property or value is within 20% of the recited value, unless otherwise indicated. For example, "substantially 5" means that the value is within 1 of 5. As used herein, the term "comprising" means "including, but not limited to," and the term "comprises" means "including, but not limited to."

[0104] All embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, unless otherwise specified.

[0105] All technical features and optional technical features of the present application can be combined with each other to form new technical solutions, unless otherwise specified.

[0106] All steps of the present application can be performed in sequence or randomly, preferably in sequence, unless otherwise specified. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method can further comprise step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0107] Unless otherwise specified, "including" and "comprising" mentioned in the present application means open-ended, and can also be closed-ended. For example, "including" and "comprising" can mean that other components not listed can also be included or contained, or only the listed components can be included or contained.

[0108] If not specifically stated, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, any of the following satisfy the condition "A or B": A is true (or present) and B is false (or not present); A is false (or not present) and B is true (or present); or both A and B are true (or present).

[0109] In recent years, as the demand for batteries as energy sources continues to increase, higher requirements are also placed on the fast charging performance of batteries. However, fast charging batteries can release a large amount of heat in a short time when charging, which can have certain safety hazards. Therefore, if the battery dynamics performance can be improved while taking into account the improvement of the direct current impedance of the battery, the comprehensive performance of the battery can be further improved.

[0110] To solve the above problems, the application provides a battery monomer, comprising a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator film located between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, the positive electrode film layer comprising a positive electrode active material, the positive electrode active material comprising a lithium-containing phosphate with an olivine structure; the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, the negative electrode film layer comprising a negative electrode active material, the average particle size Dv50 of the negative electrode active material being 8-15 μm, the negative electrode active material comprising 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 extending out from the negative electrode current collecting part along a first direction, wherein the distance between the center lines of two adjacent negative electrode tabs is 10-350 mm, and the center lines are parallel to the first direction.

[0111] As used herein, "average particle size Dv50" means the particle size corresponding to the cumulative volume distribution percentage of 50% from the small particle size side in the particle size distribution of the particles. Its determination method can refer to GB / T19077-2016 / ISO 13320:2009, and is determined by using a Malvern 2000 (MasterSizer 2000) laser particle size analyzer.

[0112] In some embodiments, in combination with FIG. 5, the current collector 11 comprises a current collecting part 11a and at least two tabs 11b arranged on the same side of the current collecting part 11a, the tabs 11b extending out from the current collecting part 11a along a first direction F1.

[0113] In some embodiments, as shown in FIG. 5, the center line L refers to a 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 dimension of each tab 11b along the length direction of the current collector 11 is equal.

[0114] In some embodiments, as shown in FIG. 5, the distance between the center lines L of two adjacent tabs 11b includes S1 or S2, where S1 and S2 can be equal (in which case the adjacent tabs are equally spaced), or S1 and S2 can not be equal (in which case the adjacent tabs are not equally spaced).

[0115] In some embodiments, as shown in FIGS. 1-3 and 5-6, the current collector 11 can be a positive current collector or a negative current collector, the current collecting portion 11a can be a positive current collecting portion 111a or a negative current collecting portion 112a, and the tab 11b can be a positive tab 111b or a negative tab 112b.

[0116] By using small-particle-size negative active materials, the present application improves the transmission path of lithium ions inside the negative active material during charging, which is conducive to improving the fast-charging capability of the battery cell. However, when the fast-charging capability of the battery cell is improved, the corresponding charging current that the battery cell can withstand is also improved. At this time, if the tab structure of the negative electrode is not reasonably arranged, it will cause the internal heat of the battery cell to accumulate during fast charging, the internal temperature of the battery will rise, and adverse reactions such as electrolyte gas production, increase in the impedance of the solid electrolyte interface film (SEI film) of the negative electrode, etc. will occur, thereby increasing the internal resistance of the battery and affecting the performance of the battery cell. By using a negative electrode tab with a reasonable distance range, the present application effectively reduces the heat accumulation inside the battery cell when the fast-charging capability is improved, reduces the internal temperature rise, and inhibits the increase in the direct current resistance (DCR) of the battery cell.

[0117] [Negative electrode tab]

[0118] In some embodiments, the negative electrode tab includes a negative current collector and a negative film layer disposed on at least one surface of the negative current collector. As an example, the negative current collector has two opposite surfaces in the thickness direction thereof, and the negative film layer is disposed on either one or both of the two opposite surfaces of the negative current collector.

[0119] In some embodiments, the negative film layer includes a negative active material.

[0120] In some embodiments, the average particle size Dv50 of the negative active material is 8 μm to 15 μm, for example 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or other unlisted values within the range of 8 μm to 15 μm. In some embodiments, the negative active material comprises graphite.

[0121] When the graphite as the negative active material has a particle size within the above range, the battery cell provided in the present application has a larger specific surface area, the migration channels of lithium ions between the graphite layers are increased, the migration path is shortened, thereby accelerating the embedding and extracting speed of lithium ions between the graphite layers, and the battery cell has good fast charging performance. Meanwhile, when the graphite as the negative active material has a particle size within the above range, the direct current internal resistance of the battery cell can also be improved, thereby reducing the heat generation of the battery, and the battery has good safety performance.

[0122] In some embodiments, the average particle size Dv50 of the negative active material is 9.5 μm to 11.5 μm, for example 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, or other unlisted values within the range of 9.5 μm to 11.5 μm.

[0123] When the negative active material (for example graphite) has a particle size within the above range, the fast charging performance and the direct current internal resistance of the battery can be further improved, and the battery has good cycle performance at the same time.

[0124] In some embodiments, the negative film layer comprises at least two negative active material layers. In some embodiments, the negative film layer comprises a first negative active material layer arranged on the surface of the negative current collector, and a second negative active material layer arranged on the side of the first negative active material layer away from the negative current collector, the negative active material in the first negative active material layer comprises a first artificial graphite, the negative active material in the second negative active material layer comprises 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.

[0125] In some embodiments, the average particle size Dv50 of the first artificial graphite is 11 μm to 15 μm, for example 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or other unlisted values within the range of 11 μm to 15 μm.

[0126] In some embodiments, the average particle size Dv50 of the second artificial graphite is 8 μm to 15 μm, for example 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or other unlisted values within the range of 8 μm to 15 μm.

[0127] In some embodiments, the second artificial graphite has an average particle size Dv50 of 9.5 μm to 11.5 μm, for example, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, or other unlisted values within the range of 9.5 μm to 11.5 μm.

[0128] The battery cell provided herein can further improve the kinetic performance of the battery when the double-layer coating scheme described above is used in the negative electrode film layer.

[0129] In some embodiments, the negative electrode film layer further optionally comprises a binder. The binder can 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).

[0130] In some embodiments, the negative electrode film layer further optionally comprises a conductive agent. The conductive agent can be selected from at least one of super-conductive carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0131] In some embodiments, the negative electrode film layer further optionally comprises other auxiliary agents, such as thickening agents (e.g., sodium carboxymethyl cellulose (CMC-Na)), and the like.

[0132] In some embodiments, the areal density of the negative electrode film layer on a single side is 0.15 g / 15 40.25 mm 2 to 0.19 g / 15 40.25 mm 2 , for example, 0.15 g / 15 40.25 mm 2 , 0.16 g / 15 40.25 mm 2 , 0.17 g / 15 40.25 mm 2 , 0.18 g / 15 40.25 mm 2 , 0.19 g / 15 40.25 mm 2 , or other unlisted values within the range of 0.15 g / 15 40.25 mm 2 to 0.19 g / 15 40.25 mm 2 .

[0133] In some embodiments, the areal density of the negative electrode film layer on a single side is 0.15 g / 15 40.25 mm 2 to 0.165 g / 15 40.25 mm 2 .

[0134] As used herein, the "areal density" of the positive electrode film layer or the negative electrode film layer has the meaning known in the art and can be tested using methods known in the art. For example, a single-side coated and cold-pressed negative electrode sheet (if a double-side coated negative electrode sheet, the negative electrode film layer on one side can be wiped off) is punched into a small round piece with an area of S1, weighed, and recorded as M1. Then the negative electrode film layer of the weighed negative electrode sheet is wiped off, the weight of the negative electrode current collector is weighed, and recorded as M0, and the areal density of the negative electrode film layer = (weight of the negative electrode sheet M1 - weight of the negative electrode current collector M0) / S1. To ensure the accuracy of the test results, multiple groups (e.g., 10 groups) of the samples to be tested can be tested, and the average value is calculated as the test result.

[0135] The battery cell provided in the present application can further improve the energy density of the battery when the coating areal density of the negative electrode film layer is within the above range, and can also avoid the influence of thick coating on the electrochemical performance, thereby further improving the fast-charging performance of the battery.

[0136] In some embodiments, the negative electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, a 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 base material. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0137] In some embodiments, the thickness of the negative electrode current collector is 4 μm to 6 μm, for example, 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.

[0138] In some embodiments, 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, for example, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc., or other unlisted values within the range of 12 to 20.

[0139] In some embodiments, 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.

[0140] In some embodiments, the single-side thickness of the negative electrode film layer corresponds to the single-side thickness of the negative electrode film layer corresponding to a battery cell at a 0% SOC state, wherein the battery cell at the 0% SOC state refers to a battery cell discharged at 1 / 3C to 2.0 V and then discharged at 0.05C to 2.0 V. In the battery cell provided in the present application, when the ratio of the single-side thickness of the negative electrode film layer to the thickness of the negative electrode current collector is within the above range, the energy density and the fast-charging performance of the battery can be further improved.

[0141] In some embodiments, the negative electrode current collector comprises a negative electrode current collecting portion and at least two negative electrode tabs disposed 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 center lines of two adjacent negative electrode tabs is 10 mm to 350 mm, the center lines being parallel to the first direction, for example, 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, or other values not listed in the range of 10 mm to 350 mm.

[0142] In some embodiments, the distance between the center lines of two adjacent negative electrode tabs is 20 mm to 330 mm, the center lines being parallel to the first direction, for example, 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, or other values not listed in the range of 20 mm to 330 mm.

[0143] In the battery cell provided in the present application, when the positive and negative electrode current collectors comprise at least two tabs having the above structural characteristics, the overcurrent capacity can be further improved, the direct current resistance of the battery cell can be improved, and thus the heat generation of the battery can be further reduced, so that the battery has better safety performance.

[0144] In some embodiments, the negative electrode tab can be prepared by dispersing the above-mentioned components for preparing the negative electrode tab, such as the negative electrode active material, the conductive agent, the binder and any other components, in a solvent (for example, deionized water) to form a negative electrode slurry; coating the negative electrode slurry on the negative electrode current collector, and then performing processes such as drying and cold pressing to obtain the negative electrode tab.

[0145] In some embodiments, the compaction density of the negative electrode tab is 1.3 g / cm 3 to 1.6 g / cm 3such as 1.3 g / cm 3 , 1.4 g / cm 3 , 1.5 g / cm 3 , 1.6 g / cm 3 , or other unlisted values within the range of 1.3 g / cm 3 to 1.6 g / cm 3 .

[0146] In some embodiments, the compacted density of the negative electrode tab is in the range of 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 , or other unlisted values within the range of 1.35 g / cm 3 to 1.55 g / cm 3 .

[0147] In some embodiments, the compacted density of the negative electrode tab corresponds to the compacted density of the negative electrode film layer of a battery cell in a 0% SOC state, where the battery cell is discharged at 1 / 3 C to 2.0 V and then discharged at 0.05 C to 2.0 V. As used herein, the “compacted density” of a tab is calculated as: compacted density = areal density / (tab thickness - current collector thickness), and can be determined according to GB / T 24533-2009.

[0148] When the compacted density of the negative electrode tab is in the above range, the energy density of the battery can be further improved while ensuring the kinetic performance.

[0149] [Positive electrode tab]

[0150] In some embodiments, the positive electrode tab includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector. As an example, the positive electrode current collector has two surfaces opposite in the thickness direction of the positive electrode current collector, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive electrode current collector.

[0151] In some embodiments, the positive electrode film layer includes a positive electrode active material.

[0152] In some embodiments, the positive electrode active material includes a lithium-containing phosphate with an olivine structure.

[0153] In some embodiments, the lithium-containing phosphate with an olivine structure has a general formula as shown in Formula I,

[0154] Li x A y Me a M b P 1-c X c Y z Formula I,

[0155] 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 comprises one or several of Na, K, Mg; Me comprises one or several of Mn, Fe, Co, Ni; M comprises one or several 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, Ce; X comprises one or several of S, Si, Cl, B, C, N; Y comprises one or several of O, F.

[0156] As used herein, "the lithium-containing phosphate composition of olivine structure has a general formula as shown in Formula I" is not only limited to the substances represented by the molecular formula, but also includes other substances formed by further modifying the substances on the basis of the molecular formula, which are not limited herein. The use of "general formula" is only for the convenience of description, and is not intended to limit the present application. It can be understood that new materials or new substances obtained by appropriately modifying the listed positive electrode active materials are also within the scope of the positive electrode active materials, and the aforementioned appropriate modification refers to acceptable modification methods for the positive electrode active materials, and non-limiting examples include coating modification.

[0157] When the lithium-containing phosphate as the positive electrode active material has the above chemical formula, the energy density of the battery can be further improved.

[0158] In some embodiments, M comprises one or several of Al, Ti, V, Mg.

[0159] In some embodiments, the positive electrode active material contains Al element, and the mass content of the Al element is 0.001% to 0.05%, which can be 0.01% to 0.05%, based on the total mass of the positive electrode active material, such as 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, or other unlisted values within the range of 0.001% to 0.05%, based on the total mass of the positive electrode active material.

[0160] In some embodiments, the positive electrode active material contains Ti element, the mass content of which is 0.001% to 0.03%, optionally 0.01% to 0.03%, based on the total mass of the positive electrode active material, such as 0.001%, 0.01%, 0.02%, 0.03%, or other values not listed in the range of 0.001% to 0.03%, based on the total mass of the positive electrode active material.

[0161] In some embodiments, the positive electrode active material contains V element, the mass content of which is 0.001% to 0.3%, optionally 0.1% to 0.3%, based on the total mass of the positive electrode active material, such as 0.001%, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, or other values not listed in the range of 0.001% to 0.3%, based on the total mass of the positive electrode active material.

[0162] In some embodiments, the positive electrode active material contains Mg element, the mass content of which is 0.001% to 0.01%, based on the total mass of the positive electrode active material, optionally 0.001%, 0.002%, 0.005%, 0.01%, or other values not listed in the range of 0.001% to 0.01%, based on the total mass of the positive electrode active material.

[0163] When the lithium-containing phosphate as the positive electrode active material contains Al, Ti, V, Mg, etc., the structural stability of the material can be further improved, and the cycle performance can be improved.

[0164] In some embodiments, in the cross section of the positive electrode film layer along the thickness direction, the lithium-containing phosphate of olivine structure 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.

[0165] In some embodiments, in the cross section of the positive electrode film layer along the thickness direction, the lithium-containing phosphate of olivine structure contains first lithium-containing phosphate particles 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, or other values not listed in the range of 0.05 μm to 0.3 μm.

[0166] In some embodiments, in the cross section of the positive electrode film layer along the thickness direction, the lithium-containing phosphate of olivine structure contains second lithium-containing phosphate particles with a longest diameter of 1 μm to 3 μm, such as 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, or other values not listed in the range of 1 μm to 3 μm.

[0167] In some embodiments, since the first lithium-containing phosphate and the second lithium-containing phosphate have been sufficiently mixed and uniformly coated onto the current collector to form the positive electrode film layer when preparing the slurry, the cross section of the positive electrode tab along the thickness direction can represent the particle size and distribution of the lithium-containing phosphate in the entire tab. When selecting the cross section, the middle and relatively flat cross section of the tab is preferred so as to more clearly observe the distribution of the lithium-containing phosphate therein.

[0168] In some embodiments, the "longest diameter" refers to: cutting the positive electrode tab including the lithium-containing phosphate particles along the thickness direction of the tab to expose the longitudinal section of the positive electrode film layer; and determining the longest diameter of the lithium-containing phosphate particles by performing a scanning electron microscope (SEM) test on the longitudinal section of the positive electrode film layer. Specifically,

[0169] The maximum value of the distance between any two points on the outer peripheral edge line of the lithium-containing phosphate particle is the "longest diameter" of the particle. In some embodiments, as shown in the longitudinal section of the tab along the thickness direction in FIG. 4, the longest diameter of the single particle satisfying the first lithium-containing phosphate particles (0.05 μm to 0.3 μm) is shown, and the shortest diameter of the single particle satisfying the second lithium-containing phosphate particles (1 μm to 3 μm) is also shown.

[0170] 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, the direct current internal resistance of the battery cell can be further improved, thereby further reducing the heat generation of the battery, and the battery has excellent safety performance.

[0171] In the battery cell provided by the present application, when the lithium-containing phosphate as the positive electrode active material contains both the first lithium-containing phosphate particles with a longest diameter of 0.05 μm to 0.3 μm and the second lithium-containing phosphate particles with a longest diameter of 1 μm to 3 μm, the compaction density of the tab can be effectively improved by the size grading of the particles, thereby making the battery cell also have a high energy density.

[0172] 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.

[0173] 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 in the lithium-containing phosphate as the positive electrode active material, the direct current internal resistance and the fast charging performance of the battery can be further improved.

[0174] It is to be noted that the smaller size first lithium-containing phosphate particle material having a longest diameter of 0.05 μm to 0.3 μm is one of the positive active materials of the battery cell 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.

[0175] The larger size second lithium-containing phosphate particle material having a longest diameter of 1 μm to 3 μm is one of the positive active materials of the battery cell of the present application, and the particle size range of 1 μm to 3 μm is a characteristic parameter of the material itself.

[0176] The two size range lithium-containing phosphate particle materials described above can be mixed as actual needs by those skilled in the art.

[0177] In some embodiments, the positive electrode film layer further optionally includes a positive electrode conductive agent. The present application does not have a particular limitation on the type of positive electrode conductive agent, and as an example, the positive electrode conductive agent includes at least one of super P, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0178] In some embodiments, the positive electrode film layer further optionally includes a positive electrode binder. The present application does not have a particular limitation on the type of positive electrode binder, and as an example, the positive electrode binder can include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylic ester-based resin.

[0179] In some embodiments, the areal density of the positive electrode film layer on one side is 0.33 g / 15 40.25 mm 2 to 0.4 g / 15 40.25 mm 2 , for example, 0.33 g / 15 40.25 mm 2 , 0.34 g / 15 40.25 mm 2 , 0.35 g / 15 40.25 mm 2 , 0.36 g / 15 40.25 mm 2 , 0.37 g / 15 40.25 mm 2 , 0.38 g / 15 40.25 mm 2 , 0.39 g / 15 40.25 mm 2 , 0.4 g / 15 40.25 mm 2 , or other unlisted values within the range of 0.33 g / 15 40.25 mm 2 to 0.4 g / 15 40.25 mm 2 .

[0180] In some embodiments, the areal density of the single side of the positive electrode film layer is 0.335 g / 15 40.25 mm 2 to 0.38 g / 15 40.25 mm 2 .

[0181] The battery cell provided in the present application can further improve the energy density of the battery when the coating areal density of the positive electrode film layer is within the above range, and can also avoid the influence of thick coating on the electrochemical performance, thereby further improving the fast charging performance of the battery.

[0182] In some embodiments, the dimension of the positive electrode film layer along the first direction is W1 mm, and the dimension 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, for example, 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, or other values not listed in the range of 3 mm to 5 mm.

[0183] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator film can be made into an electrode assembly through a winding process or a stacking process.

[0184] In some embodiments, the battery cell is a winding battery. As shown in FIG. 3, after the electrode sheet is unfolded from the winding state, the positive current collector includes a positive current collecting portion 111a and at least two positive electrode tabs 111b disposed on the same side of the positive current collecting portion 111a, the positive electrode tabs 111b extending 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 disposed on the same side of the negative current collecting portion 112a, the negative electrode tabs 112b extending from the negative current collecting portion 112a along the first direction F1. Wherein the dimension of the negative electrode film layer along the first direction W2 > the dimension of the positive electrode film layer along the first direction W1, and the difference is 3 mm to 5 mm.

[0185] In some embodiments, the battery cell is a stacked battery cell, as shown in FIG. 1 and FIG. 2, each of the positive electrode plates comprises a positive current collector, the positive current collector comprises a positive current collecting portion 111a and a positive tab 111b disposed on the positive current collecting portion 111a, the positive tab 111b extends from the positive current collecting portion 111a along a first direction F1; each of the negative electrode plates comprises a negative current collector, the negative current collector comprises a negative current collecting portion 112a and a negative tab 112b disposed on the negative current collecting portion 112a, the negative tab 112b extends from the negative current collecting portion 112a along the first direction F1. Wherein, the dimension W2 of the negative electrode film layer along the first direction is greater than the dimension W1 of the positive electrode film layer along the first direction, and the difference is 3mm to 5mm.

[0186] During the cycle process of the battery, lithium ions that cannot be timely embedded in the negative electrode may form lithium dendrites on the surface of the negative electrode, which deteriorates the cycle performance of the battery. In the battery cell provided in the present application, when the dimension W2 of the negative electrode film layer and the dimension W1 of the positive electrode film layer have the above relationship, the formation of lithium dendrites on the surface of the negative electrode can be improved, so that the battery has good cycle performance at the same time.

[0187] In some embodiments, the positive current collector can be a metal foil or a composite current collector. As an example of the metal foil, an 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 side surface of the polymer material base layer. As an example, the metal material can include at least one of aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a 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).

[0188] In some embodiments, the thickness of the positive current collector is 10μm to 15μm, such as 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, or other unlisted values within the range of 10μm to 15μm.

[0189] In some embodiments, the ratio of the single-side 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, or other unlisted values within the range of 5 to 12.

[0190] In some embodiments, the ratio of the single-side thickness of the positive electrode film layer to the thickness of the positive current collector is 6 to 10.

[0191] The battery cell provided in the present application has the ratio of the single-face thickness of the positive electrode film layer to the thickness of the positive electrode current collector within the above range, so that the thickness of the current collector is within a suitable range, and the problems of poor current-carrying capacity and low tensile strength leading to cracking of the electrode sheet caused by excessively thick or excessively thin current collectors are avoided, and the energy density and fast-charging performance of the battery are further improved.

[0192] In some embodiments, the positive electrode current collector comprises 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, 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, the center lines are parallel to the first direction, for example, 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, or other values not listed in the range of 10 mm to 350 mm.

[0193] In some embodiments, the distance between the center lines of two adjacent positive electrode tabs is 20 mm to 330 mm, for example, 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, or other values not listed in the range of 20 mm to 330 mm.

[0194] In the battery cell provided in the present application, when the positive and negative electrode current collectors comprise at least two tabs having the above structural characteristics, the current-carrying capacity can be further improved, the direct current internal resistance of the battery cell is improved, and thus the heat generation of the battery is reduced, and the battery has better safety performance.

[0195] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder, and any other components, in a solvent (for example, N-methyl pyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on the positive electrode current collector, and after drying, cold pressing, and other processes, the positive electrode sheet is obtained.

[0196] In some embodiments, the compaction density of the positive electrode sheet is 2.3 g / cm 3 to 2.6 g / cm 3 , for example, 2.30 g / cm 3 , 2.35 g / cm 32.40 g / cm 3 2.45 g / cm 3 2.50 g / cm 3 2.55 g / cm 3 2.60 g / cm 3 or other unlisted values in the range of 2.3 g / cm 3 to 2.6 g / cm 3 .

[0197] In some embodiments, the compacted density of the positive electrode tab is 2.4 g / cm 3 to 2.55 g / cm 3 .

[0198] When the compacted density of the positive electrode tab is in the above range, the energy density of the battery can be further improved while ensuring the kinetic performance.

[0199] In some embodiments, the compacted density of the positive electrode tab corresponds to the compacted density of the positive electrode film layer corresponding to the battery cell in the 0% SOC state, wherein the battery cell in the 0% SOC state refers to a battery cell discharged at 1 / 3C to 2.0V and then discharged at 0.05C to 2.0V.

[0200] [Electrolyte]

[0201] The electrolyte serves to conduct ions between the positive electrode tab and the negative electrode tab. For example, the electrolyte can be liquid, solid or gel.

[0202] In some embodiments, the electrolyte uses an electrolyte solution. The electrolyte solution includes an electrolyte salt and an organic solvent.

[0203] In embodiments of the present application, the types and contents of organic components in the electrolyte solution are of the meanings known in the art, and can be detected using devices and methods known in the art, for example, the composition of the electrolyte solution can be detected by liquid chromatography, gas chromatography, ion chromatography, liquid nuclear magnetic resonance, etc. For example, the organic components in the electrolyte solution can be qualitatively and quantitatively analyzed by gas chromatography according to GB / T 9722-2006 "General Gas Chromatography of Chemical Reagents".

[0204] The test sample in embodiments of the present application can be a freshly prepared electrolyte solution, or free electrolyte solution obtained from a battery discharged to the lower limit cutoff voltage so that the charged state of the battery is about 0% SOC.

[0205] In the embodiments of the present application, the type and content of the inorganic component / lithium salt concentration in the electrolyte are the meanings known in the art, which can be detected by using the devices and methods known in the art, for example, the qualitative or quantitative analysis of the inorganic component / lithium salt concentration in the electrolyte can be performed by ion chromatography according to the standard JY / T020-1996 "General Ion Chromatography Analysis Method". In the embodiments of the present application, the freshly prepared electrolyte can be taken as a sample, or the free electrolyte obtained from the battery after the battery is discharged (discharged to the lower limit cutoff voltage so that the charged state of the battery is about 0% SOC), and the ion chromatography analysis method is used for detection.

[0206] In some embodiments, the organic solvent includes a carboxylic acid ester solvent and a carbonate solvent.

[0207] 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.

[0208] In some embodiments, the organic solvent includes a linear carboxylic acid ester, and the mass fraction of the linear carboxylic acid ester based on the total mass of the electrolyte is 40% to 75%, for example, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or other values not listed in the range of 40% to 75%.

[0209] In some embodiments, the linear carboxylic acid ester has a general structure of R1-COO-R2, wherein R1 and R2 each independently includes one or more of C1-C5 alkyl and C1-C5 halogenated alkyl.

[0210] 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.

[0211] When the above type and mass fraction of the linear carboxylic acid ester is used as the organic solvent in the electrolyte, the linear carboxylic acid ester can effectively improve the electrolyte conductivity due to its low viscosity, thereby further improving the fast-charging performance of the battery.

[0212] In some embodiments, the organic solvent includes a carbonate solvent, and the carbonate solvent includes a linear carbonate and a cyclic carbonate, and the mass fraction of the linear carbonate based on the total mass of the electrolyte is 10% to 40%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or other values not listed in the range of 10% to 40%.

[0213] In some embodiments, the cyclic carbonate includes one or more of ethylene carbonate, propylene carbonate, and the linear carbonate includes one or more of dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.

[0214] In some embodiments, the linear carbonate includes dimethyl carbonate, and the mass percentage of the dimethyl carbonate is 5% to 15%, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or the like, or other unlisted values within the range of 5% to 15%, based on the total mass of the electrolyte.

[0215] When the above type and mass percentage of carbonate is used as the organic solvent in the electrolyte, the side reactions and the degree of gas generation of the battery during the cycle process can be improved, so that the battery has good cycle performance.

[0216] In some embodiments, the organic solvent 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, for example, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, or the like, or other unlisted values within the range of 2.0 to 7.0.

[0217] In some embodiments, the organic solvent includes dimethyl carbonate and linear carboxylic acid ester, and the mass ratio of the linear carboxylic acid ester to the dimethyl carbonate is 3.0 to 6.0.

[0218] When the above mass ratio of dimethyl carbonate and linear carboxylic acid ester is used as the organic solvent in the electrolyte, the fast-charging performance and the cycle performance of the battery can be further improved by the combination of the two solvents.

[0219] In some embodiments, the electrolyte further includes a lithium salt, for example, at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethylsulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro oxalate borate, lithium di oxalate borate, lithium difluoro di-oxalate phosphate, and lithium tetrafluoro oxalate phosphate.

[0220] In some embodiments, the mass percentage of the lithium salt is 13% to 20%, for example, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or the like, or other unlisted values within the range of 13% to 20%, based on the total mass of the electrolyte.

[0221] In some embodiments, the lithium salt includes at least two of lithium hexafluorophosphate LiPF6 and fluorosulfonylimide salt, and the fluorosulfonylimide salt includes one or more of lithium bisfluorosulfonylimide LiFSI and lithium bis-trifluoromethylsulfonylimide LiTFSI.

[0222] Lithium hexafluorophosphate is not easy to produce gas during the cycle process, which can further improve the cycle performance of the battery; and the dissociation ability of the fluorosulfonylimide salt is strong, which can further improve the fast charging performance of the battery.

[0223] In some embodiments, the lithium salt includes lithium hexafluorophosphate LiPF6 and lithium bisfluorosulfonylimide LiFSI.

[0224] In some embodiments, in the electrolyte, the mass ratio of lithium hexafluorophosphate LiPF6 to lithium bisfluorosulfonylimide 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, or other values not listed in the range of 1.2:1 to 2:1.

[0225] When lithium hexafluorophosphate and lithium bisfluorosulfonylimide in the above mass ratio range are used in the electrolyte at the same time, the fast charging performance and cycle performance of the battery can be further improved.

[0226] In some embodiments, the electrolyte further includes an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and can also include an additive capable of improving certain performance of the battery, such as an additive for improving the overcharge performance of the battery, an additive for improving the high-temperature or low-temperature performance of the battery, etc.

[0227] In some embodiments, the electrolyte includes a carbonate additive, and the carbonate additive includes fluoroethylene carbonate FEC and vinylene carbonate VC.

[0228] In some embodiments, based on the total mass of the electrolyte, the mass percentage of the carbonate additive is 0.5% to 7%, such as 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 6.5%, 7%, or other values not listed in the range of 0.5% to 7%.

[0229] In the battery cell provided in the present application, the carbonate additive with a mass percentage in the above range, such as fluoroethylene carbonate and vinylene carbonate, is further added to the electrolyte, which can form an SEI film on the negative electrode surface, thereby reducing the side reactions between the electrode and the electrolyte, and further making the battery have good cycle performance.

[0230] In some embodiments, the electrolyte comprises vinylene carbonate VC, and the mass fraction of the vinylene carbonate VC in the electrolyte is 0.5% to 2%, for example, 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%, or the like, or other values not listed in the range of 0.5% to 2%, based on the total mass of the electrolyte.

[0231] When the electrolyte is added with the vinylene carbonate in the above mass fraction range as an additive, the SEI film formed is more stable, which is conducive to further improving the cycle performance of the battery.

[0232] In some embodiments, the electrolyte comprises fluoroethylene carbonate FEC, and the mass fraction of the fluoroethylene carbonate FEC in the electrolyte is 0.1% to 1%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, or the like, or other values not listed in the range of 0.1% to 1%, based on the total mass of the electrolyte.

[0233] When the electrolyte is added with the fluoroethylene carbonate in the above mass fraction range as an additive, the SEI film formed has low impedance, which can further improve the fast-charging performance of the battery.

[0234] [Separator]

[0235] In some embodiments, the battery cell further comprises a separator. The type of the separator is not particularly limited in the present application, and any known porous structure separator with good chemical stability and mechanical stability can be selected.

[0236] 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, and is not particularly limited. When the separator is a multi-layer composite film, the materials of the layers can be the same or different, and are not particularly limited.

[0237] [Battery cell]

[0238] 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.

[0239] In some embodiments, the positive current collector, the separator, the negative current collector, and the separator are sequentially stacked and wound together; after winding, the positive tabs 111b of the positive current collector are aligned and stacked, and the negative tabs 112b of the negative current collector are aligned and stacked, as shown in FIG. 6.

[0240] In some embodiments, the battery cell further comprises a top cover comprising two electrode terminals of opposite polarity for electrically connecting with the positive or negative tabs.

[0241] In some embodiments, as shown in FIG. 6, the battery cell 10 further comprises a top cover 13 comprising two electrode terminals 131 of opposite polarity, one of which is a positive electrode terminal 131 for electrically connecting with the positive tab 111b, and the other is a negative electrode terminal 131 for electrically connecting with the negative tab 112b.

[0242] The positive tabs 111b after winding are aligned and stacked, having a larger connection area, so as to facilitate the direct electrical connection of the positive tabs 111b with the electrode terminals 131 without the need for connecting the positive tabs 111b with the electrode terminals 131 through the adapter tabs. Similarly, the negative tabs 112b after winding are aligned and stacked, having a larger connection area, so as to facilitate the direct electrical connection of the negative tabs 112b with the electrode terminals 131 without the need for connecting the negative tabs 112b with the electrode terminals 131 through the adapter tabs.

[0243] In conventional batteries, adapter tabs are needed to connect the electrode terminals with the tabs, but this will result in the loss of utilization of the electrode assembly and the reduction of the energy density of the battery. When the above structure is adopted in the battery cell provided in the present application, the cancellation of the adapter tabs can effectively solve this problem, reduce the internal resistance of the battery, and further improve the energy density and fast charging performance of the battery.

[0244] In some embodiments, the battery cell can comprise an outer package. The outer package can be used to package the above-mentioned electrode assembly and electrolyte.

[0245] 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 bag-type soft package. The material of the soft package can be plastic, and as plastic, polypropylene, polybutylene terephthalate, and polybutylene succinate, etc. can be listed.

[0246] In some embodiments, as shown in FIGS. 6-9, the battery cell 10 further comprises a shell 14, and the current collector 11 is arranged in the shell 14.

[0247] In some embodiments, as shown in FIGS. 6-9, the shell 14 is square-shaped, the thickness T of the shell is 30-55 mm, the width W of the shell is 150-250 mm, and the height H of the shell is 90-120 mm.

[0248] In some embodiments, the thickness T of the shell is 30 mm to 55 mm, for example 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, or the like, or other unlisted values within the range of 30 mm to 55 mm.

[0249] In some embodiments, the width W of the shell is 150 mm to 250 mm, for example 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, 210 mm, 220 mm, 230 mm, 240 mm, 250 mm, or the like, or other unlisted values within the range of 150 mm to 250 mm.

[0250] In some embodiments, the height H of the shell is 90 mm to 120 mm, for example 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, or the like, or other unlisted values within the range of 90 mm to 120 mm.

[0251] In some embodiments, the charging time of the battery cell from 10% SOC to 80% SOC at room temperature is 10 min to 17 min, for example 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, or the like, or other unlisted values within the range of 10 min to 17 min.

[0252] The battery cell provided in the present application has excellent fast charging performance.

[0253] In some embodiments, the shape of the battery cell is not particularly limited in the present application, which can be cylindrical, square, or any other shape. For example, FIG. 10 is a battery cell 5 in a square structure as an example. Optionally, the battery cell is a lithium ion battery or a sodium ion battery.

[0254] In some embodiments, referring to FIG. 11, the outer package can include a shell 51 and a cover plate 53. The shell 51 can include a bottom plate and a side plate connected to the bottom plate, which enclose a receiving cavity. The shell 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be arranged on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet, and the separator film can form an electrode assembly 52 through a winding process or a stacking process. The electrode assembly 52 is packaged in the receiving cavity. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, which can be selected by a person skilled in the art according to specific actual needs.

[0255] In some embodiments, a battery device, which can be a battery module, a battery pack, an energy storage battery, etc., is provided. The battery cell described above can be assembled into a battery module, and the number of battery cells contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0256] FIG. 12 is a battery module 4 as an example. Referring to FIG. 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 manner. Further, the plurality of battery cells 5 can be fixed by fasteners.

[0257] Optionally, the battery module 4 can also include a housing having an accommodation space, and the plurality of battery cells 5 are accommodated in the accommodation space.

[0258] In some embodiments, the battery module described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0259] FIGS. 13 and 14 are a battery pack 1 as an example. Referring to FIGS. 13 and 14, the battery pack 1 can include a battery box and a plurality of battery modules 4 arranged in the battery box. The battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be arranged on the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0260] [Electric device]

[0261] In addition, the present application also provides an electric device, which includes at least one of the battery cell, the battery module, or the battery pack provided by the present application. The battery cell, the battery module, or the battery pack can be used as a power source of the electric device, or can be used as an energy storage unit of the electric device. The electric device can include a mobile device (such as a mobile phone, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc., but is not limited thereto.

[0262] As the electric device, the battery cell, the battery module, or the battery pack can be selected according to the use requirement thereof.

[0263] FIG. 15 is an example of a power consuming device. The power consuming device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the demand of the power consuming device for high power and high energy density of the battery cell, a battery pack or a battery module can be used.

[0264] In some embodiments, the power consuming device includes a vehicle, and the length direction of the electrode assembly is placed along the traveling direction of the vehicle.

[0265] As another example of the device, a mobile phone, a tablet computer, a notebook computer, etc. can be used. The device usually requires thinning, and a battery cell can be used as a power source.

[0266] Embodiments

[0267] Hereinafter, embodiments of the present application will be described. The embodiments described below are exemplary and are for the purpose of explanation of the present application and should not be understood as a limitation of the present application. In the embodiments, unless a specific technique or condition is specified, the technique or condition described in the literature in the art or according to the product manual is used. Unless the manufacturer of the reagent or instrument is specified, it is a conventional product that can be obtained on the market.

[0268] Embodiment 1

[0269] 1) Negative electrode tab

[0270] The negative electrode active material artificial graphite, the conductive agent acetylene black, the binder styrene butadiene rubber, and the thickening agent sodium carboxymethyl cellulose were mixed in a mass ratio of 96:1:2:1, and then a solvent deionized water was added to stir to form a negative electrode slurry. The negative electrode slurry was uniformly coated on a negative electrode current collector copper foil, and then dried and cold-pressed to obtain a negative electrode tab. The thickness of the negative electrode current collector copper foil was 4.5 μm, the single-sided area density of the negative electrode tab was 0.155 g / 1540 mm 2 , the compacted density of the negative electrode tab was 1.47 g / cm 3 , and the size of the negative electrode film layer along the first direction was 92 mm. The volume particle size Dv50 of the artificial graphite was 11 μm.

[0271] 2) Positive electrode tab

[0272] The positive electrode active material lithium iron phosphate (LFP), the binder polyvinylidene fluoride, and the conductive agent acetylene black were mixed in a mass ratio of 97:2:1, and then a solvent N-methyl pyrrolidone (NMP) was added to stir to form a positive electrode slurry. The positive electrode slurry was uniformly coated on a positive electrode current collector aluminum foil, and then dried and cold-pressed to obtain a positive electrode tab. The thickness of the positive electrode current collector aluminum foil was 13 μm, the single-sided area density of the positive electrode tab was 0.341 mg / 1540 mm 2 , and the compacted density of the positive electrode tab was 2.51 g / cm 3, the size of the positive electrode film layer along the first direction is 88.5 mm; the positive electrode active material comprises 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 a longitudinal section of the positive electrode sheet, any region containing at least 100 lithium-containing phosphate particles of olivine structure is selected, and in the any region, the number of the first lithium-containing phosphate particles is greater than the number of the second lithium-containing phosphate particles.

[0273] 3) electrolyte

[0274] Dimethyl carbonate (DMC), ethyl acetate (EA), ethylene carbonate (EC), methyl ethyl carbonate (EMC) are uniformly mixed in a mass ratio of 10:50:35:5 to obtain an electrolyte solvent. Lithium hexafluorophosphate (LiPF6) and lithium bisfluorosulfonylimide (LiFSI) are included as lithium salts, and are fully stirred until they are completely dissolved. The mass percentages of the additives vinylene carbonate (VC) and fluoroethylene carbonate (FEC) are 0.7% and 0.3%, respectively, relative to the total mass of the electrolyte. The mass percentage of lithium hexafluorophosphate (LiPF6) is 8.9% based on the total mass of the electrolyte; the mass percentage of lithium bisfluorosulfonylimide LiFSI is 4.6%, and the lithium ion conductivity of the electrolyte is 14.5 mS / cm.

[0275] 4) separator

[0276] A commercially available polyethylene microporous film with a thickness of 7 μm and an average pore size of 80 nm is used as the separator.

[0277] 5) battery cell

[0278] The positive electrode sheet and the negative electrode sheet are cut to have tabs, the distance between the center lines of the two adjacent tabs of the positive electrode sheet is 316 mm, and the distance between the center lines of the two adjacent tabs of the negative electrode sheet is 314 mm. The positive electrode sheet, the separator, and the negative electrode sheet are stacked in order and wound to obtain a wound electrode assembly, so that each layer of the electrode assembly has at least one tab. The electrode assembly is placed in an outer packaging square aluminum shell with a thickness of 50 mm, a width of 208 mm, and a height of 103 mm, and after drying, the electrolyte is injected. After packaging, standing, formation, aging, secondary packaging, and capacity processes, a battery cell is obtained, and the tabs of the battery cell are connected to the cover plate.

[0279] Examples 2-5

[0280] The battery cells of Examples 2-5 are basically similar to Example 1, except that the particle size Dv50 of the graphite is adjusted, as shown in Tables 1-4.

[0281] Examples 6-8

[0282] The battery cells of Examples 6-8 are substantially similar to Example 1, except that the spacing between adjacent tabs is changed, as shown in Tables 1-4.

[0283] Examples 9-12

[0284] The battery cells of Examples 9-12 are substantially similar to Example 1, except that the type or content of organic solvent and lithium salt in the electrolyte is changed, as shown in Tables 1-4.

[0285] Example 13

[0286] The battery cell of Example 13 is substantially similar to Example 1, except that the negative active material is coated in two layers, as follows: a lower layer of artificial graphite with a particle size Dv50 of 13 μm and an upper layer of artificial graphite with a particle size Dv50 of 10 μm are uniformly coated on a negative current collector copper foil, which is then dried and cold-pressed to obtain a negative electrode sheet. See Tables 1-4.

[0287] Examples 14-15

[0288] The battery cells of Examples 14-15 are substantially similar to Example 1, except that the ratio of the thickness of the single-sided film layer to the current collector of the positive and negative electrodes is changed, as shown in Tables 1-4.

[0289] Comparative Examples 1-2

[0290] Comparative Examples 1-2 are substantially 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.

[0291] Comparative Examples 3-4

[0292] Comparative Examples 3-4 are substantially similar to Example 1, except that the spacing between adjacent tabs is changed. See Tables 1-4.

[0293] I. Performance Testing

[0294] 1. DC Internal Resistance

[0295] The direct current internal resistance (DCR) test of the battery cell can refer to the method in GB / T31467 "HEV High Power Lithium Ion Power Battery Performance Test Specification". For example, at room temperature, the battery cell is charged to 3.65V at a constant current of 0.33C, stands for 1min, then charged to 3.65V at a constant current of 0.1C, stands for 30min, discharged to 2.0V at a constant current of 0.33C, records the discharge capacity A0 in Ah at this time, then charges 0.5A0 Ah at a constant current of 0.33C to adjust the SOC to 50%. After the battery cell is placed at 25℃ for 2h, it is discharged at a constant current of 3C for 10s, records ΔU discharge and ΔI discharge, and the discharge DCR data of the lithium ion battery is calculated by the following formula: R discharge = ΔU discharge / ΔI discharge, wherein ΔU discharge represents the voltage change within 10s at the beginning of discharge, and ΔI discharge represents the current value within 10s at the beginning of discharge.

[0296] 2, charging time of 10% to 80% SOC

[0297] Charging time test: ① Voltage calibration: 1) The positive electrode sheet, negative electrode sheet, separator and electrolyte in the example or comparative example were prepared into a stacked three-electrode battery, which was placed at 25 °C for 30 min; 2) The battery monomer was charged to a charging cutoff voltage of 3.65 V at 0.33 C at 25 °C, and then constant voltage charging was continued at the charging cutoff voltage until the current was 0.05 C, and the charging cutoff (wherein C represents the rated capacity of the battery monomer); 3) 25 °C for 1 h; 4) The battery monomer was discharged to a discharge cutoff voltage of 2.5 V at 0.33 C at 25 °C, and the total discharge capacity C0 discharged by the battery monomer was recorded; 5) 25 °C for 1 h. ② Normal temperature charging test: 1) The positive electrode sheet, negative electrode sheet, separator and electrolyte in the example or comparative example were prepared into a stacked three-electrode battery, which was placed for 30 min; 2) 0.33 C0 direct current discharge to the discharge cutoff voltage of 2.5 V, which corresponds to 0% SOC at this time; 3) 5 min of standing; 4) 5C0 constant current charging to the negative electrode potential of 0 V, reading the capacity C1 at this time, which corresponds to C1 / C0 SOC at this time; 5) 5 min of standing; 6) 4.5C0 constant current charging to the negative electrode potential of 0 V, reading the capacity C2 at this time, which corresponds to C2 / C0 SOC at this time; 7) 5 min of standing; 8) 4C0 constant current charging to the negative electrode potential of 0 V, reading the capacity C3 at this time, which corresponds to C3 / C0 SOC at this time; 9) 5 min of standing; 10) 3C0 constant current charging to the negative electrode potential of 0 V, reading the capacity C4 at this time, which corresponds to C4 / C0 SOC at this time; 11) 5 min of standing; 12) 2C0 constant current charging to the negative electrode potential of 0 V, reading the capacity C5 at this time, which corresponds to C5 / C0 SOC at this time; 13) 5 min of standing; 14) 1C0 constant current charging to the negative electrode potential of 0 V, reading the capacity C6 at this time, which corresponds to C6 / C0 SOC at this time; 15) 5 min of standing; 16) 0.8C0 constant current charging to the negative electrode potential of 0 V, reading the capacity C7 at this time, which corresponds to C7 / C0 SOC at this time; 17) 5 min of standing; 18) 0.5C0 constant current charging to the negative electrode potential of 0 V, reading the capacity C8 at this time, which corresponds to C8 / C0 SOC at this time; 19) 5 min of standing; 20) 0.33C0 constant current charging to the negative electrode potential of 0 V, reading the capacity C9 (also C0) at this time, which corresponds to 100% SOC. The total charging time from 10% SOC to 80% SOC charging process is added to obtain the required charging time.

[0298] 3. Volume energy density

[0299] The battery monomer was discharged at 0.33C to 2.5V at 25°C, rested for 5min, charged to the upper limit cutoff voltage 3.65V at 0.33C, and then charged to a current of 0.05C at constant voltage, rested for 5min; discharged to the cutoff voltage 2.5V at 0.33C, and recorded the discharge capacity at this time and obtained the discharge energy E0. The volumetric energy density (Wh / L) = discharge energy E0 / volume of the monomer (L).

[0300] 4. Cycle performance

[0301] Charged to 3.65V at 0.5C charge rate, then charged to 0.05C at constant voltage at 3.65V, rested for 10min, and then discharged to 2.5V at 1C discharge rate, rested for 10min, and the above one charge-discharge was one cycle, until the battery capacity decayed to 80% of the nominal capacity, the test was stopped, and recorded as the cycle number @ 80% SOH.

[0302] II. Analysis of test results of each example and comparative example

[0303] The battery monomers of each example and comparative example were prepared according to the above method, and each performance parameter was measured, and the results are shown in Tables 1-5 below.

[0304] Table 1. Preparation parameters of negative electrode sheet

[0305] Table 2. Preparation parameters of positive electrode sheet and electrolyte

[0306] Table 3. Preparation parameters of electrolyte

[0307] Table 4. Battery performance parameters

[0308] In the battery monomers of Examples 1-15, lithium-containing phosphate containing olivine structure was used as the positive electrode active material in the positive electrode film layer; graphite with an average particle size Dv50 of 8-15μm was used as the negative electrode active material in the negative electrode film layer; and as shown in Figure 5, the negative electrode current collector includes at least two negative electrode tabs, and the distance between the center lines of the adjacent two negative electrode tabs is 10-350mm; therefore, the battery monomers prepared in Examples 1-15 all have excellent fast charging performance, energy density, cycle performance, and low direct current internal resistance.

[0309] The average particle size Dv50 of the graphite in the negative electrode film layer of Comparative Examples 1-2 is out of the range of 8-15μm, wherein: the Dv50 of the graphite in Comparative Example 1 is too large, and the Dv50 of the graphite in Comparative Example 2 is too small.

[0310] From the comparison of Comparative Examples 1-2 and Examples 1-15, it can be seen that when the average particle size Dv50 of the graphite is greater than the range of 15 μm, the fast-charging performance and the direct current internal resistance of the battery cell cannot be effectively improved; and when the average particle size Dv50 of the graphite is less than the range of 8 μm, the cycle performance of the battery cell cannot be effectively improved; therefore, when the average particle size Dv50 of the graphite in the negative electrode film layer is in the range of 8 μm to 15 μm, the cycle performance, the fast-charging performance and the direct current internal resistance of the battery can be improved, and when the range is exceeded, the comprehensive performance of the battery is poor.

[0311] 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.

[0312] From the comparison of 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, the fast-charging performance and the direct current internal resistance of the battery cannot be effectively improved, and the comprehensive performance of the battery is poor; at the same time, as the range is exceeded, the cycle performance, the fast-charging performance and the direct current internal resistance of the battery are further deteriorated, and the comprehensive performance of the battery is further reduced. 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, the fast-charging performance and the direct current internal resistance of the battery can be improved, and when the range is exceeded, the comprehensive performance of the battery is poor.

[0313] In Examples 1-5, the average particle size Dv50 of the graphite in the negative electrode film layer is in the range of 8 μm to 15 μm, and the battery cell prepared thereby can have excellent energy density, fast-charging performance, cycle performance, and low direct current internal resistance. In addition, the results also show that when the Dv50 of the 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 is decreased to a certain extent and the direct current internal resistance is increased to a certain extent; and when the Dv50 of the 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 and the direct current internal resistance is decreased to a certain extent, but the cycle performance is decreased to a certain extent. Therefore, the Dv50 of the graphite in the negative electrode film layer should be in the range of 8 μm to 15 μm, so as to improve the fast-charging performance, the cycle performance and the direct current internal resistance of the battery; and when the Dv50 of the 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 the graphite is too low, the energy density of the battery is reduced.

[0314] In the embodiments 1, 6-8, the distance between the center lines of any two adjacent negative tabs is 10-350 mm, and the distance between the center lines of any two adjacent positive tabs is 10-350 mm, and the battery cells prepared thereby can have excellent fast charging performance, cycle performance, and low DC internal resistance. Meanwhile, the results also show that when the distance between the center lines of any two adjacent tabs gradually decreases in the range of 10-350 mm, the fast charging performance and DC internal resistance of the battery are further improved, and the overall performance of the battery is better.

[0315] In the embodiments 1, 9-12, the electrolyte uses the following formulation, and the battery cells prepared thereby can have excellent energy density, fast charging performance, cycle performance, and low DC internal resistance: the organic solvent uses linear carboxylic acid ester (such as ethyl acetate) with a mass fraction of 40-75%, linear carbonate (such as DMC, EMC) with a mass fraction of 10-40%, and cyclic carbonate (such as ethylene carbonate) with a mass fraction of 5-15%, and the mass ratio of linear carboxylic acid ester (such as ethyl acetate) to dimethyl carbonate is 2.0-7.0; the lithium salt uses LiPF6 and LiFSI with a mass fraction of 13-20%, and the mass ratio of LiPF6 to LiFSI is 1.2:1-2:1.

[0316] Meanwhile, the comparison among the embodiments 1, 9, 10 shows that as the proportion of linear carboxylic acid ester (such as ethyl acetate) and LiFSI in the electrolyte gradually increases, the fast charging performance and DC internal resistance of the battery are further improved; and as the proportion of linear carbonate (such as DMC) and LiPF6 in the electrolyte gradually increases, the cycle performance of the battery is further improved.

[0317] Meanwhile, the comparison among the embodiments 1, 11, 12 shows that when only linear carboxylic acid ester (such as ethyl acetate) exists in the organic solvent of the electrolyte, and no carbonate exists, and only LiFSI exists in the lithium salt, and no LiPF6 exists, the fast charging performance and DC internal resistance of the battery are further improved, but the cycle performance of the battery is not good; when only linear carbonate (such as DMC) exists in the organic solvent of the electrolyte, and no linear carboxylic acid ester exists, and only LiPF6 exists in the lithium salt, 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 carbonate and linear carboxylic acid ester with the above mass ratio are used as the organic solvent in the electrolyte, and LiPF6 and LiFSI with the above mass ratio are used as the lithium salt, the fast charging performance, DC internal resistance, and cycle performance of the battery can be further improved by the mutual matching of various solvents and lithium salts, and the overall performance of the battery is better.

[0318] In Embodiments 1 and 13, at least one layer of graphite is included in the negative electrode film layer as the negative electrode active material, and the average particle size Dv50 thereof is in the range of 8 μm to 15 μm, and the battery cell prepared thereby can have excellent energy density, fast charging performance, cycle performance, and low direct current internal resistance. In addition, it can be seen from the comparison between Embodiments 1 and 13 that when the negative electrode film layer includes two layers of artificial graphite with different particle sizes as the negative electrode active material layer (the first negative electrode active material layer is arranged on the surface of the negative electrode current collector, and the second negative electrode active material layer is arranged 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), the fast charging performance and direct current internal resistance of the battery can be further improved, and the overall performance of the battery is better.

[0319] In Embodiments 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, and the battery cell prepared thereby can have excellent energy density, fast charging performance, cycle performance, and low direct current 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 in 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 in the above range, the fast charging performance, direct current internal resistance, and cycle performance of the battery can be further improved.

[0320] In Embodiments 1-15, as shown in FIG. 4, in the cross section of the positive electrode film layer along the thickness direction, the lithium-containing phosphate in the positive electrode film layer 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, and the battery cell prepared thereby can have excellent energy density, fast charging performance, cycle performance, and low direct current internal resistance.

[0321] In Embodiments 1-15, the compaction density of the positive electrode sheet is 2.3 g / cm 3 to 2.6 g / cm 3 , and the compaction density of the negative electrode sheet is 1.3 g / cm 3 to 1.6 g / cm 3 , and the battery cell prepared thereby can have excellent energy density, fast charging performance, cycle performance, and low direct current internal resistance.

[0322] Note that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having substantially the same configuration, function, and effect as the technical idea of the present application are included in the technical scope of the present application. Furthermore, other modes constructed by applying various modifications to the embodiments, or by combining part of the configurations of the embodiments, which can be conceived by those skilled in the art without departing from the spirit of the present application, are also included in the scope of the present application.

Claims

1. A battery cell, comprising a positive electrode tab, a negative electrode tab, and a separator film between the positive electrode tab and the negative electrode tab, wherein the positive electrode tab 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 tab comprises 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 comprises a negative electrode active material, and the negative electrode active material has an average particle size Dv50 of 8 μm to 15 μm, and the negative electrode active material comprises graphite; the negative electrode current collector comprises a negative electrode current collecting portion and at least two negative electrode tabs disposed 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, and a distance between center lines of adjacent two negative electrode tabs is 10 mm to 350 mm, the center lines being parallel to the first direction; the positive electrode current collector comprises 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, and a distance between center lines of adjacent two positive electrode tabs is 10 mm to 350 mm, the center lines being parallel to the first direction; the distance between the center lines of the adjacent two negative electrode tabs is 20 mm to 330 mm; the distance between the center lines of the adjacent two positive electrode tabs is 20 mm to 330 mm; the average particle size Dv50 of the negative electrode active material is 9.5 μm to 11.5 μm; the battery cell comprises an electrolyte, and the electrolyte comprises an organic solvent, the organic solvent comprises a carboxylic acid ester solvent and a carbonate solvent; the organic solvent comprises a linear carboxylic acid ester, and a mass fraction of the linear carboxylic acid ester is 40% to 75% based on a total mass of the electrolyte; the linear carboxylic acid ester has a general structure of R1-COO-R2, wherein R1 and R2 each independently comprise one or more of C1-C5 alkyl and C1-C5 haloalkyl; the linear carboxylic acid ester comprises one or more of ethyl acetate, methyl acetate, methyl propionate, propyl acetate, ethyl formate, and isopropyl formate; the organic solvent comprises a carbonate solvent, the carbonate solvent comprises a linear carbonate and a cyclic carbonate, and a mass fraction of the linear carbonate is 10% to 40% based on a total mass of the electrolyte; the cyclic carbonate comprises one or more of ethylene carbonate and propylene carbonate, and the linear carbonate comprises one or more of dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; the linear carbonate comprises dimethyl carbonate, and a mass fraction of the dimethyl carbonate is 5% to 15% based on a total mass of the electrolyte; the electrolyte comprises dimethyl carbonate and a linear carboxylic acid ester, and a mass ratio of the linear carboxylic acid ester to the linear dimethyl carbonate is 2.0 to 7.0; and the mass ratio of the linear carboxylic acid ester to the dimethyl carbonate is 3.0 to 6.

0. ​ ​ ​ 2. The battery cell of claim 1, wherein, ​ 3. The battery cell of claim 1, wherein, ​ 4. The battery cell of claim 2, wherein, ​ 5. The battery cell according to any one of claims 1 to 4, characterized in that, ​ 6. The battery cell of any one of claims 1 to 5, wherein, ​ 7. The battery cell of claim 6, wherein, ​ 8. The battery cell of claim 7, wherein, ​ 9. The battery cell of claim 8, wherein, ​ 10. The battery cell according to any one of claims 6 to 9, characterized in that, ​ 11. The battery cell of claim 10, wherein, ​ 12. The battery cell of claim 11, wherein, ​ 13. The battery cell of any one of claims 6 to 12, wherein, ​ 14. The battery cell of claim 13, wherein, ​ 15. The battery cell of any one of claims 6 to 14, wherein, The electrolyte comprises a lithium salt, and the mass percentage of the lithium salt is 13% to 20% based on the total mass of the electrolyte.

16. The battery cell of claim 15, wherein, The lithium salt comprises at least two of lithium hexafluorophosphate and fluorosulfonylimide salt, wherein the fluorosulfonylimide salt comprises one or more of lithium bisfluorosulfonylimide LiFSI and lithium bis-trifluoromethylsulfonylimide LiTFSI.

17. The battery cell of claim 15, wherein, The lithium salt comprises lithium hexafluorophosphate LiPF6 and lithium bisfluorosulfonylimide LiFSI.

18. The battery cell of claim 17, wherein, In the electrolyte, the mass ratio of lithium hexafluorophosphate LiPF6 to lithium bisfluorosulfonylimide LiFSI is 1.2:1 to 2:

1.

19. The battery cell of any one of claims 6-18, wherein, The electrolyte further comprises an additive, and the additive comprises a carbonate-based additive.

20. The battery cell of claim 19, wherein, The mass percentage of the carbonate-based additive in the electrolyte is 0.5% to 7% based on the total mass of the electrolyte.

21. The battery cell of claim 19 or 20, wherein, The carbonate-based additive comprises vinylene carbonate VC and fluoroethylene carbonate FEC.

22. The battery cell of claim 19 or 20, wherein, The additive comprises vinylene carbonate VC, and the mass percentage of the vinylene carbonate VC in the electrolyte is 0.5% to 2% based on the total mass of the electrolyte.

23. The battery cell of claim 19 or 20, wherein, The additive comprises fluoroethylene carbonate FEC, and the mass percentage of the fluoroethylene carbonate FEC in the electrolyte is 0.1% to 1% based on the total mass of the electrolyte.

24. The battery cell of any one of claims 1-23, wherein, The lithium-containing phosphate of olivine structure has a general composition according to Formula I, Li x A y Me a M b P 1-c X c Y z Formula I, 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 comprises one or more of Na, K, and Mg; Me comprises one or more of Mn, Fe, Co, and Ni; M comprises 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, Ce; X comprises one or more of S, Si, Cl, B, C, and N; and Y comprises one or more of O and F.

25. The battery cell of claim 24, wherein, M comprises one or more of Al, Ti, V, and Mg.

26. The battery cell of claim 24 or 25, wherein, 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 0.01-0.05% 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 0.01-0.03% 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 0.1-0.3% 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 0.001-0.01% based on the total mass of the positive electrode active material. In the cross section of the positive electrode film layer along the thickness direction, the lithium-containing olivine phosphate comprises first lithium-containing phosphates with a longest diameter of 0.05 μm to 0.3 μm and second lithium-containing phosphates with a longest diameter of 1 μm to 3 μm.

27. The battery cell of any one of claims 1-26, wherein, ​ 28. The battery cell of claim 27, wherein, 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 of any one of claims 1-28, wherein, The positive electrode film layer has a dimension of W1 mm along the first direction, and the negative electrode film layer has a dimension of W2 mm along the first direction, where W2 > W1, and the difference between W2 and W1 is 3 mm to 5 mm.

30. The battery cell of any one of claims 1-29, wherein, The compacted density of the positive electrode plate is 2.3 g / cm 3 to 2.6 g / cm 3 .

31. The battery cell of any one of claims 1-29, wherein, The compacted density of the positive electrode plate is 2.4 g / cm 3 to 2.55 g / cm 3 .

32. The battery cell of any one of claims 1-31, wherein, The single-side coating area density of the positive electrode sheet is 0.33 g / 1540.25 mm 2 to 0.4 g / 1540.25 mm 2 .

33. The battery cell of any one of claims 1-31, wherein, The single-side coating area density of the positive electrode sheet is 0.335 g / 1540.25 mm 2 to 0.38 g / 1540.25 mm 2 .

34. The battery cell of any one of claims 1-33, wherein, The compacted density of the negative electrode sheet is 1.3 g / cm 3 to 1.6 g / cm 3 .

35. The battery cell of any one of claims 1-33, wherein, The compacted density of the negative electrode sheet is 1.35 g / cm 3 to 1.55 g / cm 3 .

36. The battery cell of any one of claims 1-35, wherein, The single-side coating area density of the negative electrode sheet is 0.15 g / 1540.25 mm 2 to 0.19 g / 1540.25 mm 2 .

37. The battery cell of any one of claims 1-35, wherein, The single-side coating area density of the negative electrode sheet is 0.15 g / 15 40.25 mm 2 to 0.165 g / 15 40.25 mm 2 .

38. The battery cell of any one of claims 1-37, wherein, The thickness of the negative electrode current collector is 4-6 μm.

39. The battery cell of any one of claims 1-38, wherein, 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.

40. The battery cell of any one of claims 1-38, wherein, 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.

41. The battery cell of any one of claims 1-40, wherein, 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 a first artificial graphite, and the negative electrode active material in the second negative electrode active material layer includes a 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.

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

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

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

45. The battery cell of any one of claims 1-44, wherein, The battery monomer 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 electrical connection with the positive electrode tab or the negative electrode tab.

46. The battery cell of any one of claims 1-45, wherein, The battery monomer further includes a shell, the shell is square, the thickness of the shell is 30 mm to 55 mm, the width of the shell is 150 mm to 250 mm, and the height of the shell is 90 mm to 120 mm.

47. The battery cell of any one of claims 1-46, wherein, The battery monomer is configured to have a charging time of 10-17 min from 10% SOC to 80% SOC at room temperature.

48. A battery device, comprising: The battery device includes at least one of a battery module, a battery pack, and an energy storage device.

49. An electrical device, comprising: The battery monomer or the battery device includes any one of claims 1 to 48.

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