Battery monomer, battery device and electric equipment

Abstract

The invention provides a battery monomer, a battery device and electric equipment, the battery monomer comprises a shell, an electrode assembly and an electrolyte, the electrode assembly comprises a positive pole piece, a negative pole piece and an isolating membrane located between the positive pole piece and the negative pole piece, the positive pole piece comprises a positive current collector and a positive membrane layer, and the negative pole piece comprises a negative current collector and a negative membrane layer. The positive electrode current collector comprises a positive electrode main body part and a positive electrode tab part, the positive electrode tab part extends out of the positive electrode main body part, the positive electrode film layer is located on at least one side of the positive electrode main body part, and the size of the positive electrode film layer is 200-700 mm along the direction in which the positive electrode tab part extends out of the positive electrode main body part; the electrolyte comprises chain carboxylic ester, and based on the total mass of the electrolyte, the mass ratio of the chain carboxylic ester is 5%-50%.

Description

[0001] Cross - reference to related applications This application claims the priority of PCT patent application PCT / CN2025 / 071087 entitled "Battery Cell, Battery Device and Electrical Equipment" filed on January 7, 2025, the entire content of which is incorporated herein by reference. Technical Field

[0002] This application relates to the field of batteries, and specifically, to battery cells, battery devices and electrical equipment. Background Art

[0003] Batteries are not only applied to energy storage power systems such as hydroelectric, thermal, wind and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in multiple fields such as military equipment and aerospace. The battery cells in the related art cannot meet the requirements of fast charging and high energy density at the same time. Summary of the Invention

[0004] In a first aspect of the present application, a battery cell is provided. The battery cell includes a housing, an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode tab, a negative electrode tab and a separator located between the positive electrode tab and the negative electrode tab. Among them, the positive electrode tab includes a positive current collector and a positive film layer. The positive current collector includes a positive main body portion and a positive electrode ear portion. The positive electrode ear portion extends from the positive main body portion. The positive film layer is located on at least one side of the positive main body portion. The positive film layer includes a lithium-containing phosphate. The size of the positive film layer along the length direction of the positive electrode tab is 200 mm - 700 mm; the negative electrode tab includes a negative current collector and a negative film layer. The negative current collector includes a negative main body portion and a negative electrode ear portion. The negative electrode ear portion extends from the negative main body portion. The negative film layer is located on at least one side of the positive main body portion. The negative film layer includes graphite; the electrolyte includes a chain carboxylic acid ester. Based on the total mass of the electrolyte, the mass ratio of the chain carboxylic acid ester is 5% - 50%. Thus, by increasing the size of the positive film layer, the energy density of the battery cell is increased. At the same time, with the above content of the chain carboxylic acid ester, the conductivity of the electrolyte is increased, and the fast charging performance of the battery cell is improved. Furthermore, a battery cell with both high energy density and excellent fast charging performance is obtained.

[0005] According to some embodiments of the present application, along the length direction of the positive electrode tab, the size of the positive film layer is 400 mm - 650 mm. Thus, the energy density of the battery cell is further increased.

[0006] According to some embodiments of the present application, based on the total mass of the electrolyte, the mass percentage of the chain carboxylic ester is 8% - 30%. Thereby, while improving the conductivity of the electrolyte, the risk of gas generation of the battery cell under high-temperature conditions is reduced, and a battery cell with excellent fast-charging performance and high-temperature cycle life is obtained.

[0007] According to some embodiments of the present application, the conductivity of the electrolyte at room temperature is 9.5 mS / cm - 19 mS / cm. Thereby, the fast-charging performance of the battery cell is improved.

[0008] According to some embodiments of the present application, the conductivity of the electrolyte at room temperature is 9.7 mS / cm - 13.5 mS / cm. Thereby, while increasing the lithium-ion migration rate, the risk of gas generation of the electrolyte is reduced.

[0009] According to some embodiments of the present application, the viscosity of the electrolyte at room temperature is 2 mPa·s - 5 mPa·s. Thereby, the lithium-ion migration rate is increased and the internal resistance of the battery cell is reduced.

[0010] According to some embodiments of the present application, the density of the electrolyte at room temperature is 1.05 g / mL - 1.35 g / mL. Thereby, the migration rate of lithium ions in the electrolyte is increased and the internal resistance of the battery cell is reduced.

[0011] According to some embodiments of the present application, the chain carboxylic ester includes the compound shown in Formula I: Formula I, wherein, R 1 includes a hydrogen atom, C 1 -C 5 alkyl, C 1 -C 5 haloalkyl, or one or more of them, and R 2 includes C 1 -C 5 alkyl, C 1 -C 5 haloalkyl, or one or more of them. Thereby, the chain carboxylic esters of the above types have a relatively small molecular weight, which can improve the conductivity of the electrolyte. By matching with long electrodes, a battery cell with high energy density, excellent fast-charging performance and excellent high-temperature cycle life can be obtained.

[0012] According to some embodiments of the present application, R 1 includes a hydrogen atom, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, or one or more of them; and / or R 2 includes C 1 -C3 An alkyl group, C 1 -C 3 One or more of a haloalkyl group. Thereby, the conductivity of the electrolyte is increased.

[0013] According to some embodiments of the present application, the chain carboxylic acid ester includes Formula I-1, Formula I-2, Formula I-3, Formula I-4, Formula I-5, Formula I-6, Formula I-7, Formula I-8. Thereby, the chain carboxylic acid esters of the above types have a relatively small molecular weight, and the conductivity of the electrolyte can be increased.

[0014] According to some embodiments of the present application, the single-sided coating weight of the positive electrode film layer is 200 mg / 1540.25 mm 2 -340 mg / 1540.25 mm 2 , and may be optionally 240 mg / 1540.25 mm 2 -300 mg / 1540.25 mm 2 . Thereby, the energy density of the battery cell is increased.

[0015] According to some embodiments of the present application, when the battery cell is in a state of 100% SOC, the compaction density of the positive electrode film layer is 2.5 g / cm 3 -2.8 g / cm 3 . Thereby, the energy density of the battery cell is increased.

[0016] According to some embodiments of the present application, the lithium-containing phosphate includes at least one of a lithium iron phosphate material and a lithium manganese iron phosphate material. Thereby, the safety and cycle performance of the battery cell are improved.

[0017] According to some embodiments of the present application, the positive electrode film layer further includes a lithium supplement agent. Based on the total mass of the positive electrode film layer, the mass ratio of the lithium supplement agent is 0.5%-2.5%. Thereby, the loss of active lithium during the formation stage is compensated, and the energy density and cycle life of the battery cell are improved.

[0018] According to some embodiments of the present application, the lithium supplement agent includes one or more of lithium nickel cobalt manganese oxide, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium metasilicate, lithium manganate, lithium tartrate, trilithium citrate, lithium nickelate, and lithium ferrate.

[0019] According to some embodiments of the present application, the positive electrode sheet and the negative electrode sheet are stacked. Thereby, the utilization rate of the space inside the battery cell is improved, and the energy density of the battery cell is increased.

[0020] According to some embodiments of the present application, the battery cell includes a housing, a first end cover assembly, and a second end cover assembly. The housing, the first end cover assembly, and the second end cover assembly define a receiving cavity. The first end cover assembly includes a first end cover and at least one positive terminal, and the positive electrode main body is electrically connected to the positive terminal through the positive electrode tab; and / or, the second end cover assembly includes a second end cover and at least one negative terminal, and the negative electrode main body is electrically connected to the negative terminal through the negative electrode tab. Thereby, the risk of short circuit between the positive and negative electrodes is reduced, and the safety of the battery cell is improved.

[0021] According to some embodiments of the present application, the first end cover assembly includes one positive terminal and one negative terminal. The positive electrode main body is electrically connected to the positive terminal through the positive electrode tab, and the negative electrode main body is electrically connected to the negative terminal through the negative electrode tab; and / or, the second end cover assembly includes one positive terminal and one negative terminal. The positive electrode main body is electrically connected to the positive terminal through the positive electrode tab, and the negative electrode main body is electrically connected to the negative terminal through the negative electrode tab. Thereby, the overcurrent capacity of the battery cell is improved.

[0022] According to some embodiments of the present application, the first end cover assembly and the second end cover assembly are disposed at both ends of the housing. In the length direction of the battery cell, the electrode terminals of the same polarity on the first end cover assembly and the second end cover assembly are arranged in a staggered manner. Optionally, the electrode terminals of the same polarity are arranged diagonally in the length direction of the battery cell. Thereby, the temperature rise of the battery cell during charging can be reduced, and further the impedance of the battery cell can be reduced.

[0023] According to some embodiments of the present application, the charging time of the battery cell configured to charge from 10% SOC to 80% SOC is 5 min - 10.5 min. Thereby, the fast charging performance of the battery cell is improved.

[0024] The second aspect of the present application provides a battery device, including the battery cell provided in the first aspect of the present application. The battery device is at least one of a battery module, a battery pack, and an energy storage device.

[0025] The third aspect of the present application provides an electrical device, including the battery cell provided in the first aspect of the present application or the battery device provided in the second aspect of the present application. The battery cell or the battery device is used to provide electrical energy.

[0026] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned by practice of the present application. Description of the Drawings

[0027] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of illustrating the preferred embodiments and are not considered to be a limitation of the present application. Also, in all the drawings, the same reference numerals are used to represent the same components. In the drawings: Figure 1 is a schematic diagram of the positive electrode plate of an embodiment of the present application.

[0028] Figure 2 is a schematic diagram of the stacking manner of the electrode assembly of an embodiment of the present application.

[0029] Figure 3 is a schematic diagram of the structure of the housing of an embodiment of the present application.

[0030] Figure 4 is a schematic diagram of the first end cap assembly of an embodiment of the present application.

[0031] Figure 5 is Figure 4 the exploded view of the first end cap assembly in

[0032] Figure 6 is Figure 4 the schematic diagram of another perspective of the first end cap assembly in

[0033] Figure 7 is Figure 6 the cross-sectional view of the first end cap assembly along the AA' direction in

[0034] Figure 8 is a schematic diagram of the second end cap assembly of an embodiment of the present application.

[0035] Figure 9 is Figure 8 the exploded view of the second end cap assembly in

[0036] Figure 10 is Figure 8 the schematic diagram of another perspective of the second end cap assembly in

[0037] Figure 11 is Figure 10 the cross-sectional view of the second end cap assembly along the BB' direction in

[0038] Figure 12 is a schematic diagram of the structure of the battery cell of an embodiment of the present application.

[0039] Figure 13 It is a schematic structural diagram of a first end cap assembly according to an embodiment of the present application.

[0040] Figure 14 is Figure 13 an exploded view of the first end cap assembly in

[0041] Figure 15 is Figure 13 a schematic structural diagram of the first end cap assembly from another perspective in

[0042] Figure 16 is Figure 15 a sectional view of the first end cap assembly along the CC’ direction in

[0043] Figure 17 It is a schematic structural diagram of a second end cap assembly according to an embodiment of the present application.

[0044] Figure 18 is Figure 17 an exploded view of the second end cap assembly in

[0045] Figure 19 is Figure 17 a schematic structural diagram of the second end cap assembly from another perspective in

[0046] Figure 20 is Figure 19 a sectional view of the second end cap assembly along the DD’ direction in

[0047] Figure 21 It is a schematic structural diagram of an electrode assembly according to an embodiment of the present application.

[0048] Figure 22 It is a schematic structural diagram of an electrode assembly according to another embodiment of the present application.

[0049] Figure 23 It is a schematic diagram of an electrical device according to an embodiment of the present application.

[0050] Explanation of reference numerals: 1 Battery cell; 11 Housing; 12 First end cap assembly; 13 Second end cap assembly; 121 First end cap; 1211 First opening; 1212 Liquid injection hole; 122 Positive terminal; 123 First insulating member; 1231 Second opening; 124 First sealing member; 125 First positioning member; 126 Second insulating member; 127 Riveting block; 131 Second end cap; 1311 Third opening; 132 Negative terminal; 133 Third insulating member; 1331 Fourth opening; 134 Second sealing member; 135 Second positioning member; 136 Fourth insulating member; 137 Pressure relief mechanism; 2 Positive electrode plate; 21 Positive current collector; 211 Positive main body portion; 212 Positive electrode tab; 2121 First positive ear; 2122 Second positive ear; 22 Positive electrode film layer; 3 Negative electrode plate; 31 First negative ear; 32 Second negative ear; 4 Separator; 20 Electrode assembly. Detailed implementation manners

[0051] The embodiments of the technical solutions of the present application will be described in detail below. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, so they are only examples and cannot be used to limit the protection scope of the present application.

[0052] Referring to "embodiment" herein means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0053] If there is no special description, all the implementation manners and optional implementation manners of the present application can be combined with each other to form a new technical solution.

[0054] If there is no special description, all the technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0055] If there is no special description, all the steps of the present application can be carried out sequentially or randomly, and preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) carried out sequentially, or may include steps (b) and (a) carried out sequentially. For example, it is mentioned that the method may further include step (c), indicating that step (c) can be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0056] At present, from the perspective of the development of the market situation, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydroelectric, thermal, wind, and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in many fields such as military equipment and aerospace. With the continuous expansion of the application fields of batteries, the market demand is also constantly increasing. The battery monomers in the related technologies cannot simultaneously meet the requirements of high specific energy, fast charging, and long cycle life.

[0057] For the battery monomer proposed in this application, in order to improve the energy density of the battery monomer, the coating length of the positive electrode film layer on the positive electrode tab is extended to increase the loading of lithium phosphate, thereby improving the energy density of the battery monomer. However, after the size of the positive electrode film layer increases, the conduction path of electrons becomes longer, restricting the fast charging ability of the battery monomer. By further increasing the content of chain carboxylic esters in the electrolyte, even for a longer electrode tab, the electrolyte can fully infiltrate the positive electrode film layer, thereby significantly increasing the electron-conducting ability and ion-conducting ability of the positive electrode film layer, and also improving the transport ability of lithium ions in the liquid phase, significantly improving the fast charging performance of the battery monomer with a longer size. However, the increase in the content of chain carboxylic esters will also exacerbate the side reactions inside the battery, cause gas generation in the electrolyte, easily exacerbate the increase of acidic substances in the electrolyte, and then cause the problem of corroding the solid electrolyte interface (SEI) film, which has an impact on the cycle life at high temperatures. In this application, by comprehensively regulating the electrode tab length and solvent composition, the appropriate content of chain carboxylic esters for the battery monomer with a positive electrode film layer size of 200 mm - 700 mm is found, enabling the battery monomer to have both good fast charging ability and high-temperature cycle life.

[0058] The battery monomer proposed in this application can be used in electrical equipment that uses the battery monomer as a power source or various energy storage systems that use the battery monomer as an energy storage element. The electrical equipment can include, but is not limited to, mobile phones, tablets, laptop computers, electric toys, power tools, battery cars, electric vehicles, ships, spacecraft, etc. Among them, the electric toys can include fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric plane toys, etc., and the spacecraft can include airplanes, rockets, space shuttles, and spaceships, etc.

[0059] In the first aspect of this application, a battery monomer is proposed. The battery monomer includes a housing, an electrode assembly, and an electrolyte. The electrode assembly includes a positive electrode tab, a negative electrode tab, and a separator located between the positive electrode tab and the negative electrode tab.

[0060] Among them, with reference to Figure 1, the positive electrode sheet 2 includes a positive current collector 21 and a positive electrode film layer 22. The positive current collector 21 includes a positive electrode main body portion 211 and a positive electrode tab 212. The positive electrode tab 212 extends from the positive electrode main body portion 211. The positive electrode film layer 22 is located on at least one side of the positive electrode main body portion 211. The positive electrode film layer includes a positive electrode active material, and the positive electrode active material includes a lithium-containing phosphate. The dimension of the positive electrode film layer 22 in the length direction of the positive electrode sheet 2 is 200 mm - 700 mm.

[0061] The negative electrode sheet includes a negative current collector and a negative electrode film layer. The negative current collector includes a negative electrode main body portion and a negative electrode tab. The negative electrode tab extends from the negative electrode main body portion. The negative electrode film layer is located on at least one side of the positive electrode main body portion. The negative electrode film layer includes a negative electrode active material, and the negative electrode active material includes graphite.

[0062] The electrolyte includes a chain carboxylic ester. Based on the total mass of the electrolyte, the mass ratio of the chain carboxylic ester is 5% - 50%.

[0063] Thus, for the battery cell proposed in this application, the coating length of the positive electrode film layer is relatively long, which can increase the loading of the lithium-containing phosphate on the positive electrode sheet, and thus obtain a battery cell with a relatively high energy density. At the same time, by adding 5% - 50% of the chain carboxylic ester to the electrolyte, the conductivity of the electrolyte can be increased. In the case where the length of the positive electrode film layer is relatively long, the conductivity of the electrode sheet can be improved, and thus the fast charging performance of the battery cell can be improved.

[0064] In this application, the dimension of the positive electrode film layer refers to the dimension of the positive electrode film layer on at least one side of the positive electrode main body portion in the length direction of the positive current collector. Referring to Figure 1 L in it, which is the dimension of the positive electrode film layer.

[0065] As an example, the dimension L of the positive electrode film layer can be 200 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, 550 mm, 600 mm, 650 mm, 700 mm, etc., or can be a range composed of any of the above values. Thus, the content of the lithium-containing phosphate on the positive electrode sheet is increased, and a battery cell with good safety performance, good cycling performance and high energy density is obtained.

[0066] According to some specific embodiments of the present application, along the direction in which the positive electrode tab extends from the positive electrode main body portion, the dimension L of the positive electrode film layer can be 400 mm - 650 mm. Thus, while increasing the volume energy density of the battery cell, the conduction path of electrons is reduced, and the fast charging performance of the battery cell is improved.

[0067] According to some embodiments of the present application, the conductivity of the electrolyte at room temperature is 9.5 mS / cm - 19 mS / cm.

[0068] As an example, the conductivity of the electrolyte can be 9.5 mS / cm, 10 mS / cm, 12 mS / cm, 14 mS / cm, 16 mS / cm, 18 mS / cm, 19 mS / cm, etc., or can be a range composed of any of the above values. Thereby, the rate performance of the battery cell is improved.

[0069] According to some embodiments of the present application, the conductivity of the electrolyte at room temperature is 9.7 mS / cm - 13.5 mS / cm. Thereby, while improving the fast charging performance of the battery cell, the risk of gas generation of the battery cell under high temperature conditions is reduced, and the high temperature cycle performance of the battery cell is improved.

[0070] In the present application, after disassembling the battery cell to obtain the electrolyte, the conductivity of the electrolyte at room temperature can be tested with a conductivity meter referring to HG-T 4067-2015.

[0071] According to some embodiments of the present application, based on the total mass of the electrolyte, the mass proportion of the chain carboxylic ester can be 5% - 50%. For example, it can be 5%, 10%, 20%, 30%, 40%, 50%, etc., or can be a range composed of any of the above values. By making the content of the chain carboxylic ester within the above range, on the one hand, the viscosity of the electrolyte can be reduced, the internal resistance of the battery cell can be reduced, the migration rate of lithium ions can be increased, and the fast charging performance of the battery cell can be improved; on the other hand, the risk of gas generation of the electrolyte under high temperature conditions can be reduced, and the high temperature cycle life of the battery cell can be improved, thereby obtaining a battery cell with both high energy density, excellent fast charging performance and high temperature cycle life.

[0072] According to some specific embodiments of the present application, based on the total mass of the electrolyte, the mass proportion of the chain carboxylic ester can be 8% - 30%. Thereby, while improving the fast charging performance of the battery cell, the risk of gas generation of the battery cell under high temperature conditions is reduced, and the high temperature cycle life of the battery is improved.

[0073] In the present application, after disassembling the battery cell to obtain the electrolyte, the qualitative and quantitative detection of the chain carboxylic ester can be carried out by gas chromatography - ion chromatography (GC-IC).

[0074] According to some embodiments of the present application, the viscosity of the electrolyte at room temperature can be 2 mPa·s - 5 mPa·s. For example, it can be 2 mPa·s, 2.5 mPa·s, 3 mPa·s, 3.5 mPa·s, 4 mPa·s, 4.5 mPa·s, 5 mPa·s, etc., or can be a range composed of any of the above values. Thereby, the viscosity of the electrolyte is small, the migration rate of lithium ions can be increased, the internal resistance of the battery cell can be reduced, and the fast charging performance of the battery cell can be improved.

[0075] In this application, after disassembling the battery cell to obtain the electrolyte, the viscosity of the electrolyte is measured by a kinematic viscometer. The viscosity of the electrolyte at room temperature can be measured with reference to GB / T 10247-2008.

[0076] According to some embodiments of the present application, the density of the electrolyte at room temperature can be 1.05 g / mL - 1.35 g / mL. For example, it can be 1.05 g / mL, 1.1 g / mL, 1.15 g / mL, 1.2 g / mL, 1.25 g / mL, 1.3 g / mL, 1.35 g / mL, etc., or can be a range composed of any of the above values. Thereby, the viscosity of the electrolyte is reduced, the migration rate of lithium ions in the electrolyte is increased, the internal resistance of the battery cell is reduced, and the fast charging performance of the battery cell is improved.

[0077] In this application, after disassembling the battery cell to obtain the electrolyte, the density of the electrolyte is measured by a liquid densitometer. The density of the electrolyte at room temperature can be measured with reference to GB / T 2013-2010.

[0078] According to some embodiments of the present application, the chain carboxylic ester may include a compound represented by Formula I: Formula I, wherein, R 1 includes a hydrogen atom, C 1 -C 5 alkyl, C 1 -C 5 haloalkyl, or one or more of them, and R 2 includes C 1 -C 5 alkyl, C 1 -C 5 haloalkyl, or one or more of them.

[0079] Thereby, when the mass ratio of the chain carboxylic ester represented by Formula I is 5% - 50%, on the one hand, using the chain carboxylic ester with the above content can improve the wetting ability of the electrolyte in the electrode film layer. Especially in a longer battery cell, it can improve the wetting uniformity of the electrolyte in the length direction of the electrode, improve the electron transport ability of the active material, and in addition, can also increase the migration rate of lithium ions in the electrolyte, thereby improving the fast charging performance of the battery cell; on the other hand, too high a content of the chain carboxylic ester also increases the gas generation inside the battery cell, which is not conducive to the cycle of the battery at high temperature. Therefore, an appropriate amount of the chain carboxylic ester can also reduce the risk of gas generation of the electrolyte under high temperature conditions and improve the high temperature cycle life of the battery.

[0080] According to some embodiments of the present application, R 1 includes a hydrogen atom, C 1 -C 3An alkyl group, C 1 -C 3 One or more of haloalkyl groups. For example, R 1 may include one or more of a hydrogen atom, a methyl group, an ethyl group, a propyl group, a fluoromethyl group, a fluoroethyl group, and a fluoropropyl group. Thereby, the conductivity of the electrolyte is increased.

[0081] According to some embodiments of the present application, R 2 includes C 1 -C 3 alkyl groups, C 1 -C 3 One or more of haloalkyl groups. For example, R 2 may be one or more of a methyl group, an ethyl group, a propyl group, a fluoromethyl group, a fluoroethyl group, and a fluoropropyl group. Thereby, the conductivity of the electrolyte is increased.

[0082] According to some embodiments of the present application, the chain carboxylic ester may include Formula I-1, Formula I-2, Formula I-3, Formula I-4, Formula I-5, Formula I-6, Formula I-7, One or more of Formula I-8. Thereby, the chain carboxylic esters of the above types have a relatively small molecular weight, and the conductivity of the electrolyte can be increased.

[0083] According to some embodiments of the present application, the single-sided coating weight of the positive electrode film layer may be 200 mg / 1540.25 mm 2 -340 mg / 1540.25 mm 2 , for example, may be 200 mg / 1540.25 mm 2 , 230 mg / 1540.25 mm 2 , 260 mg / 1540.25 mm 2 , 290 mg / 1540.25 mm 2 , 320 mg / 1540.25 mm 2 , 340 mg / 1540.25 mm 2 etc., or may be a range composed of any of the above values. Thereby, by making the size of the positive electrode film layer 200 mm - 700 mm and at the same time making the coating weight of the positive electrode film layer within the above range, the energy density of the battery cell can be increased.

[0084] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro bis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0085] In some embodiments, the electrolyte may optionally further include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives capable of improving certain battery performances, such as additives for improving the overcharge performance of the battery, additives for improving the high-temperature or low-temperature performance of the battery, and the like.

[0086] According to some specific embodiments of the present application, the single-sided coating weight of the positive electrode film layer may be 240 mg / 1540.25 mm 2 - 300 mg / 1540.25 mm 2 . For example, it may be 240 mg / 1540.25 mm 2 , 260 mg / 1540.25 mm 2 , 280 mg / 1540.25 mm 2 , 300 mg / 1540.25 mm 2 etc., or may be a range composed of any of the above values. Thereby, the energy density of the battery cell is increased.

[0087] The present application provides a method for testing the coating weight of the positive electrode film layer: disassemble the positive electrode sheet from the battery cell. For example, take the single-sided coated positive electrode sheet (if it is a double-sided coated sheet, the positive electrode film layer on one side can be wiped off first), punch it into small round pieces with an area of S 1 , weigh it, and record it as M 1 . Then wipe off the positive electrode film layer of the above-mentioned weighed positive electrode sheet, weigh the weight of the positive electrode current collector, and record it as M 0 . The single-sided coating weight of the positive electrode film layer = (M 1 - M 0 ) / S 1 .

[0088] According to some embodiments of the present application, when the battery cell is in a state of 100% SOC, the compaction density of the positive electrode film layer may be 2.5 g / cm 3 - 2.8 g / cm 3 . For example, it may be 2.5 g / cm 3 , 2.55 g / cm 3 , 2.6 g / cm 3 , 2.65 g / cm 3 , 2.7 g / cm 3 , 2.75 g / cm3 , 2.8 g / cm 3 and so on, or can be a range composed of any of the above values. Thus, when the compaction density of the positive electrode film layer is within the above range, the stacking of the positive electrode sheet is relatively dense, which is beneficial to improving the energy density of the battery cell, and the contact resistance between particles is small, which can further reduce the internal resistance of the battery cell, reduce the heat generation of the battery cell, and improve the high-temperature performance of the battery cell.

[0089] The present application provides a method for testing the compaction density of a positive electrode film layer: charge at a constant current of 1 / 3C to 3.8V, charge at a constant voltage of 3.8V to 0.05C, disassemble the battery cell to obtain the positive electrode sheet, for example, take a single-sided coated positive electrode sheet (if it is a double-sided coated sheet, the positive electrode film layer on one side can be wiped off first), and punch it into small round pieces with an area of S 1 , weigh it, and record it as M 1 , measure its thickness H 1 . Then wipe off the positive electrode film layer of the above-mentioned weighed positive electrode sheet, weigh the weight of the positive electrode current collector, record it as M 0 , measure its thickness H 0 . The single-sided coating weight of the positive electrode film layer = (M 1 - M 0 ) / S 1 , the thickness of the positive electrode film layer = H 1 - H 0 , and the compaction density of the positive electrode film layer = the single-sided coating weight of the positive electrode film layer / the thickness of the positive electrode film layer.

[0090] According to some embodiments of the present application, the lithium-containing phosphate includes at least one of lithium iron phosphate material and lithium manganese iron phosphate material. Thus, the cycle performance of the battery cell is improved.

[0091] According to some embodiments of the present application, the lithium-containing phosphate includes the compound shown in Formula II: Li x1 A y1 Me a M b P 1-c X c Y z Formula II, Among them, 0.5 ≤ x1 ≤ 1.3, 0 ≤ y1 ≤ 1.3, and 0.9 ≤ x1 + y1 ≤ 1.3, 0.9 ≤ a ≤ 1.5, 0 ≤ b ≤ 0.5, and 0.9 ≤ a + b ≤ 1.5, 0 ≤ c ≤ 0.5, 3 ≤ z ≤ 5, A includes one or more of Na, K, and Mg, Me includes one or more of Mn, Fe, Co, and Ni, M includes one or more of B, Mg, Al, P, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce, X includes one or more of S, Si, Cl, B, C, and N, and Y includes one or two of O and F.

[0092] According to some embodiments of the present application, the positive electrode film layer further includes a lithium supplementing agent. Based on the total mass of the positive electrode film layer, the mass ratio of the lithium supplementing agent can be 0.5% - 2.5%. For example, it can be 0.5%, 0.7%, 1%, 1.3%, 1.6%, 1.85%, 2.2%, 2.5%, etc., or it can be a range composed of any of the above values. Thus, lithium ions can be supplemented to the positive electrode film layer, compensating for the loss of lithium ions, improving the capacity of the battery cell, and improving the energy density and cycle life of the battery cell.

[0093] According to some embodiments of the present application, the lithium supplementing agent can include one or more of lithium nickel cobalt manganate, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium metasilicate, lithium manganate, lithium tartrate, trilithium citrate, lithium nickelate, and lithium ferrate. Thus, the energy density of the battery cell is improved.

[0094] According to some specific embodiments of the present application, the lithium supplementing agent includes lithium ferrate. During the battery cycling process, lithium ferrate can release oxygen free radicals and participate in the formation of the negative electrode film, further reducing the internal resistance of the battery cell and improving the fast charging performance of the battery cell.

[0095] According to some embodiments of the present application, refer to Figure 2 , the positive electrode tab 2 and the negative electrode tab 3 are stacked. Specifically, a separator 4 is provided between the positive electrode tab 2 and the negative electrode tab 3 to prevent short - circuiting between the positive electrode tab 2 and the negative electrode tab 3. Thus, the utilization rate of the space inside the battery cell is improved, and the energy density of the battery cell is improved.

[0096] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum foil may be used. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0097] In some embodiments, the positive electrode film layer may optionally further include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0098] In some embodiments, the positive electrode film layer may optionally further include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0099] In some embodiments, the positive electrode plate may be prepared by the following method: dispersing the components for preparing the positive electrode plate, such as the positive electrode active material, conductive agent, binder, and any other components, in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on the positive electrode current collector, and after processes such as drying and cold pressing, the positive electrode plate can be obtained.

[0100] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0101] In some embodiments, the negative electrode active material may be a negative electrode active material for a battery known in the art. By way of example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and titanates. The silicon-based material may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxides, and tin alloys. When the battery is a lithium-ion battery, the titanate is lithium titanate; when the battery is a sodium-ion battery, the titanate is sodium titanate. However, the present application is not limited to these materials, and other conventional materials that can be used as the negative electrode active material of the battery may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0102] In some embodiments, the negative electrode active material layer may also optionally include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0103] In some embodiments, the negative electrode active material layer may also optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0104] In some embodiments, the negative electrode active material layer may also optionally include other additives, such as a thickener (such as sodium carboxymethyl cellulose (CMC-Na)).

[0105] In some embodiments, the negative electrode plate may be prepared by the following method: dispersing the components for preparing the negative electrode plate, such as the negative electrode active material, the conductive agent, the binder, and any other components, in a solvent (such as deionized water) to form a negative electrode slurry; coating the negative electrode slurry on a negative electrode current collector, and after processes such as drying and cold pressing, the negative electrode plate can be obtained.

[0106] According to some embodiments of the present application, the negative electrode tab includes a negative electrode current collector and a negative electrode film layer. The negative electrode current collector includes a negative electrode main body portion and a negative electrode tab portion, and the negative electrode tab portion extends from the negative electrode main body portion; the battery cell includes a housing, a first end cap assembly, and a second end cap assembly. The housing, the first end cap assembly, and the second end cap assembly define an accommodation cavity. The first end cap assembly includes a first end cap and at least one positive terminal, and the positive electrode main body portion is electrically connected to the positive terminal through the positive electrode tab portion; and / or, the second end cap assembly includes a second end cap and at least one negative terminal, and the negative electrode main body portion is electrically connected to the negative terminal through the negative electrode tab portion.

[0107] Specifically, the battery cell includes a housing, a first end cap assembly, and a second end cap assembly. The first end cap assembly includes a first end cap, and the second end cap assembly includes a second end cap. Refer to Figure 3 , the first end cap assembly and the second end cap assembly may be disposed at two ends of the housing 11 along its length direction, or the first end cap assembly and the second end cap assembly are disposed at two ends of the housing 11 along its width direction. Specifically, when the two ends of the housing 11 along its length direction respectively have openings, the first end cap assembly and the second end cap assembly may be disposed at two ends of the housing 11 along its length direction and are adapted to respectively cover the openings; when the two ends of the housing 11 along its width direction respectively have openings, the first end cap assembly and the second end cap assembly may be disposed at two ends of the housing 11 along its width direction and are adapted to respectively cover the openings to isolate the internal environment of the battery cell from the external environment. The shapes of the first end cap assembly and the second end cap assembly may be adapted to the shape of the housing 11 to cooperate with the housing 11.

[0108] In some embodiments, the first end cap assembly and the second end cap assembly may be disposed at two ends of the housing 11 along its length direction, that is, the first end cap assembly and the second end cap assembly are disposed on the smaller side surfaces of the housing 11, so as to save the space of the battery cell along the width direction, thereby accommodating wider tabs and improving the energy density of the battery cell.

[0109] In some embodiments, the housing 11 is formed by bending and then splicing by welding, and the weld marks are integrated on the smaller side surfaces of the housing 11 extending along the length direction, which helps to reduce the problem of cracking of the welding area caused by the expansion of the battery cell along the thickness direction and improves the reliability of the housing 11.

[0110] The first end cap and the second end cap can be independently made of a material with a certain hardness and strength (such as aluminum alloy), so that the first end cap and the second end cap have higher strength. When the first end cap and the second end cap are squeezed, the deformation of the first end cap and the second end cap is reduced, and the safety performance of the battery cell is improved. In some embodiments, the first end cap and the second end cap can be selected as steel shells.

[0111] As an example, the first end cap assembly, the second end cap assembly, and the housing can be independent components.

[0112] As an example, the first end cap assembly, the second end cap assembly, and the housing can also be integrated. Specifically, the first end cap assembly or the second end cap assembly and the housing can form a common connection body before the electrode assembly and other components are inserted into the housing. After the electrode assembly and other components are inserted into the housing 11, the second end cap assembly or the first end cap assembly is then used to cover the opening of the housing along the length direction or the width direction.

[0113] According to some embodiments of the present application, referring to Figures 4 - 7 , the first end cap assembly 12 includes a first end cap 121 and a first electrode terminal 122.

[0114] In some embodiments, referring to Figure 5 the disassembly schematic diagram of the first end cap assembly 12, the first end cap assembly 12 includes a first cover plate 121, a first electrode terminal 122, a first insulating member 123, a first sealing member 124, a first positioning member 125, a second insulating member 126, and a riveting block 127, and is assembled into Figure 4 the first end cap assembly 12 shown.

[0115] In some embodiments, Figure 7 is Figure 6 the cross-sectional schematic diagram along the AA' direction. Combining Figure 5 and Figure 7It can be seen that a first opening 1211 is provided on the first end cap 121, the first electrode terminal 122 penetrates through the first end cap 121, and a first insulating member 123 is provided between the first end cap 121 and the first electrode terminal 122. This assembly method is used to isolate the electrical connection components in the housing 11 from the first end cap 121 on the one hand, and at the same time keep the first electrode terminal 122 insulated from the first end cap 121 to reduce the risk of short circuit. A second opening 1231 is provided on the first insulating member 123, and the first electrode terminal 122 sequentially passes through the second opening 1231 and the first opening 1211. A first sealing member 124 for insulation and sealing is provided between the first opening 1211 and the first electrode terminal 122. The first sealing member 124 is provided with a through hole to allow the first electrode terminal 122 to pass through. A second insulating member 126 and a riveting block 127 are provided on the side of the first end cap 121 away from the electrode assembly. The second insulating member 126 and the riveting block 127 are also provided with through holes, and the first electrode terminal 122 sequentially passes through the through holes of the second insulating member 126 and the riveting block 127. Among them, the second insulating member 126 is used to insulate the first electrode terminal 122 from the first end cap 121, and the riveting block 127 is used to fix the first electrode terminal 122 on the first end cap 121.

[0116] In some embodiments, referring to Figure 5 , the first end cap assembly further includes at least two first positioning members 125 to prevent the first electrode terminal 122 from deflecting and improve the stress strength of the first electrode terminal 122.

[0117] In some embodiments, referring to Figure 5 , the first end cap assembly 12 includes a liquid injection hole 1212 for injecting electrolyte into the accommodation cavity of the housing 11.

[0118] Referring to Figures 8 - 11 , the second end cap assembly 13 includes a second end cap 131 and a second electrode terminal 132.

[0119] In some embodiments, referring to Figure 9 the disassembly schematic diagram of the second end cap assembly 13, the second end cap assembly 13 includes a second end cap 131, a second electrode terminal 132, a third insulating member 133, a second sealing member 134, a fourth insulating member 136, a riveting block 127 and a second positioning member 135, and is assembled into Figure 8 the second end cap assembly 13 shown.

[0120] In some embodiments, Figure 11 is Figure 10 a cross-sectional schematic diagram along the BB' direction. CombiningFigure 9 and Figure 11 As can be seen, a third opening 1311 is provided on the second end cap 131. The second electrode terminal 132 penetrates through the second end cap 131. A third insulating member 133 is provided between the second end cap 131 and the second electrode terminal 132. This assembly method is used to isolate the electrical connection components in the housing 11 from the second end cap 131 on the one hand, and at the same time keep the second electrode terminal 132 insulated from the second end cap 131 to reduce the risk of short circuit. A fourth opening 1331 is provided on the third insulating member 133. The second electrode terminal 132 sequentially passes through the fourth opening 1331 and the third opening 1311. A second sealing member 134 for insulation and sealing is provided between the third opening 1311 and the second electrode terminal 132. A through hole is provided on the second sealing member 134 to enable the second electrode terminal 132 to pass through. A fourth insulating member 136 and a riveting block 127 are provided on the side of the second end cap 131 away from the electrode assembly. The fourth insulating member 136 and the riveting block 127 are also provided with through holes. The second electrode terminal 132 sequentially passes through the through holes of the fourth insulating member 136 and the riveting block 127. Among them, the fourth insulating member 136 is used to insulate the second electrode terminal 132 from the second end cap 131, and the riveting block 127 is used to fix the second electrode terminal 132 on the second end cap 131.

[0121] In some embodiments, referring to Figure 9 , the second end cap assembly 13 further includes a second positioning member 135. The second positioning member 135 includes at least two to prevent the second electrode terminal 132 from deflecting and improve the stress strength of the second electrode terminal 132.

[0122] According to some embodiments of the present application, referring to Figures 8 - 11 , a pressure relief mechanism 137 is provided on the second end cap 131. When the internal pressure of the housing exceeds the threshold, the pressure relief mechanism 137 can release the internal pressure of the housing.

[0123] As an example, the pressure relief mechanism 137 and the second end cap 131 are two separate components, which are separately formed and then installed together. The pressure relief mechanism 137 can be components such as an explosion-proof film, an explosion-proof valve, a safety valve, etc. The pressure relief mechanism 137 can be installed on the second end cap 131 by means of bonding, welding, etc. When the internal pressure of the battery cell reaches the threshold, the pressure relief mechanism 137 opens at least part of the pressure relief holes, and the discharge cut-off inside the battery cell is discharged through the pressure relief holes to release the internal pressure of the battery cell.

[0124] According to some embodiments of the present application, the first end cap assembly includes a positive terminal and a negative terminal. The positive electrode main body is electrically connected to the positive terminal through the positive electrode ear portion, and the negative electrode main body is electrically connected to the negative terminal through the negative electrode ear portion.

[0125] According to some embodiments of the present application, the second end cap assembly includes a positive terminal and a negative terminal. The positive electrode main body is electrically connected to the positive terminal through the positive electrode ear portion, and the negative electrode main body is electrically connected to the negative terminal through the negative electrode ear portion. Thereby, the overcurrent capacity of the battery cell is improved.

[0126] Reference Figure 12 , the first end cap assembly 12 and the second end cap assembly 13 are disposed at two ends of the housing 11 along its length direction. The first end cap assembly 12 includes a positive terminal and a negative terminal, and the second end cap assembly includes a positive terminal and a negative terminal.

[0127] Specifically, referring to Figures 13 - 16 , the first end cap assembly 12 includes a first end cap 121 and two electrode terminals with opposite polarities (a first electrode terminal 122 and a second electrode terminal 132). Among them, when the first electrode terminal 122 is the positive terminal, the second electrode terminal 132 is the negative terminal; when the first electrode terminal 122 is the negative terminal, the second electrode terminal is the positive terminal.

[0128] In some embodiments, referring to Figure 14 the disassembled schematic diagram of the first end cap assembly 12, the first end cap assembly 12 includes a first end cap 121, a first electrode terminal 122, a second electrode terminal 132, a first insulating member 123, two first sealing members 124, two second insulating members 126, two riveting blocks 127 and four first positioning members 125, and is assembled into Figure 13 the first end cap assembly shown.

[0129] In some embodiments, Figure 16 is Figure 15 a cross-sectional schematic diagram along the CC' direction. Combining Figure 14 and Figure 16It can be seen that two first openings 1211 are provided on the first end cover 121. The first electrode terminal 122 and the second electrode terminal 132 respectively penetrate through the first end cover 121. First insulating members 123 are provided between the first end cover 121, the first electrode terminal 122, and the second electrode terminal 132. This assembly method is used, on the one hand, to isolate the electrical connection components in the housing 11 from the first end cover 121, and at the same time to insulate the first electrode terminal 122 and the second electrode terminal 132 from the first end cover 121 to reduce the risk of short circuit. Two second openings 1231 are provided on the first insulating member 123. The first electrode terminal 122 and the second electrode terminal 132 respectively pass through the correspondingly provided second opening 1231 and the first opening 1211 in sequence. First sealing members 124 for insulation and sealing are provided between the first opening 1211 and the first electrode terminal 122 and the second electrode terminal 132. Through holes are provided on the first sealing member 124 so that the first electrode terminal 122 and the second electrode terminal 132 can pass through. Two second insulating members 126 and two riveting blocks 127 are provided on the side of the first end cover 121 away from the electrode assembly. Through holes are also provided on the second insulating member 126 and the riveting block 127. The first electrode terminal 122 and the second electrode terminal 132 pass through the correspondingly provided through holes on the second insulating member 126 and the riveting block 127 in sequence. Among them, the second insulating member 126 is used to insulate the electrode terminal from the first end cover 121, and the riveting block 127 is used to fix the electrode terminal on the first end cover 121.

[0130] Reference Figures 17 - 20 , the second end cover assembly 13 includes a second end cover 131 and two electrode terminals with opposite polarities (the first electrode terminal 122 and the second electrode terminal 132). When the first electrode terminal 122 is the positive electrode terminal, the second electrode terminal 132 is the negative electrode terminal; when the first electrode terminal 122 is the negative electrode terminal, the second electrode terminal is the positive electrode terminal.

[0131] In some embodiments, reference Figure 18 to the disassembly schematic diagram of the second end cover assembly 13 in Figure 17 . The second end cover assembly 13 includes a second end cover 131, a first electrode terminal 122, a second electrode terminal 132, a third insulating member 133, two second sealing members 134, a fourth insulating member 136, a riveting block 127, and a second positioning member 135, and is assembled into

[0132] the second end cover assembly 13 shown in Figure 20 is Figure 19 a cross-sectional schematic diagram along the DD' direction. Combining Figure 18 andFigure 20 As can be seen, two third openings 1311 are provided on the second end cap 131. The first electrode terminal 122 and the second electrode terminal 132 penetrate through the second end cap 131. A third insulating member 133 is provided between the second end cap 131, the first electrode terminal 122, and the second electrode terminal 132. This assembly method is used on the one hand to isolate the electrical connection components in the housing 11 from the second end cap 131, and at the same time to insulate the first electrode terminal 122 and the second electrode terminal 132 from the second end cap 131 to reduce the risk of short circuit. Two fourth openings 1331 are provided on the third insulating member 133. The first electrode terminal 122 and the second electrode terminal 132 are sequentially inserted through the correspondingly provided fourth openings 1331 and the third openings 1311. A second sealing member 134 for insulation and sealing is provided between the third opening 1311 and the first electrode terminal 122 and the second electrode terminal 132. The second sealing member 134 is provided with through holes to allow the first electrode terminal 122 and the second electrode terminal 132 to pass through. On the side of the second end cap 131 away from the electrode assembly, two fourth insulating members 136 and two riveting blocks 127 are provided. The fourth insulating members 136 and the riveting blocks 127 are also provided with through holes. The first electrode terminal 122 and the second electrode terminal 132 sequentially pass through the through holes correspondingly provided on the fourth insulating members 136 and the riveting blocks 127. Among them, the fourth insulating member 136 is used to insulate the electrode terminal from the second end cap 131, and the riveting block 127 is used to fix the electrode terminal on the second end cap 131.

[0133] According to some embodiments of the present application, the first end cap assembly and the second end cap assembly are arranged at both ends of the housing. In the length direction of the battery cell, the electrode terminals of the same polarity on the first end cap assembly and the second end cap assembly are arranged in a staggered manner.

[0134] According to some embodiments of the present application, the electrode terminals of the same polarity are arranged diagonally in the length direction of the battery cell.

[0135] Thereby, the temperature rise of the battery cell can be reduced during charging, and further the impedance of the battery cell can be reduced.

[0136] Reference Figure 21, the electrode assembly 20 includes four tab ears. At one end in the length direction of the electrode assembly 20, two tab ears extend out, which are the first positive tab ear 2121 and the first negative tab ear 31 respectively. At the other end in the length direction of the electrode assembly 20, two tab ears extend out, which are the second positive tab ear 2122 and the second negative tab ear 32 respectively. The first positive tab ear 2121 is electrically connected to the first electrode terminal 122 on the first end cover, the first negative tab ear 31 is electrically connected to the second electrode terminal 132 on the first end cover, the second positive tab ear 2122 is electrically connected to the first electrode terminal 122 on the second end cover 131, and the second negative tab ear 32 is electrically connected to the second electrode terminal 132 on the second end cover 131. Thus, the electrode terminals with different polarities are arranged diagonally in the length direction of the battery cell, and the temperature rise of the battery cell can be reduced during charging, thereby reducing the impedance of the battery cell.

[0137] Reference Figure 22 , the electrode assembly 20 includes four tab ears. At one end in the length direction of the electrode assembly 20, two tab ears extend out, which are the first positive tab ear 2121 and the first negative tab ear 31 respectively. At the other end in the length direction of the electrode assembly 20, two tab ears extend out, which are the second positive tab ear 2122 and the second negative tab ear 32 respectively. The two positive tab ears at both ends in the length direction of the electrode assembly 20 are asymmetrically arranged, and the two negative tab ears at both ends in the length direction of the electrode assembly 20 are asymmetrically arranged. The first positive tab ear 2121 is electrically connected to the first electrode terminal 122 on the first end cover, the first negative tab ear 31 is electrically connected to the second electrode terminal 132 on the first end cover, the second positive tab ear 2122 is electrically connected to the first electrode terminal 122 on the second end cover 131, and the second negative tab ear 32 is electrically connected to the second electrode terminal 132 on the second end cover 131. Thus, the electrode terminals with the same polarity are arranged diagonally in the length direction of the battery cell, which can improve the over-current capacity of the battery cell. At the same time, the wiring inside the battery cell can be reduced, making it easier to assemble.

[0138] According to some embodiments of the present application, the charging time of the battery cell configured to charge from 10% SOC to 80% SOC is 5 min - 10.5 min. Thus, the fast charging performance of the battery cell is improved.

[0139] The present application does not particularly limit the type of the separator, and any well-known porous separator with good chemical stability and mechanical stability can be selected.

[0140] In some embodiments, the material of the separator can be selected from at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0141] The second aspect of the present application provides a battery device, including the battery cell provided in the first aspect of the present application, and the battery device is at least one of a battery module, a battery pack, and an energy storage device.

[0142] The third aspect of the present application provides an electrical device, including the battery cell provided in the first aspect of the present application or the battery device provided in the second aspect of the present application, and the battery cell or the battery device is used to provide electrical energy. The electrical device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, energy storage systems, etc., but is not limited thereto.

[0143] As the electrical device, a battery module or a battery pack can be selected according to its usage requirements.

[0144] Figure 23 It is an electrical device as an example. The electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the high power and high energy density requirements of the electrical device for the battery, a battery pack or a battery module can be adopted.

[0145] Another example of the device can be a mobile phone, a tablet computer, a laptop computer, etc. This device usually requires thinness and lightness, and a battery can be used as the power source.

[0146] In order to make the technical problems, technical solutions, and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to the embodiments and the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way constitutes a limitation to the present application and its application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0147] Embodiment 1 1. Positive electrode tab The positive electrode tab includes a positive electrode current collector aluminum foil, and positive electrode film layers are provided on both surfaces of the aluminum foil. In the state of 100% SOC, the compaction density is 2.65 g / cm 3 , the coating weight of the single-sided positive electrode film layer is 290 mg / 1540.25 mm 2 , the size of the positive electrode film layer is 200 mm. Based on the total mass of the single-sided positive electrode film layer, the positive electrode film layer includes 95.8% of lithium iron phosphate material, 0.9% of lithium supplement agent Li 5 FeO4 , 1.1% conductive agent carbon black, 2.2% binder polyvinylidene fluoride (PVDF). The surface of lithium iron phosphate has a carbon coating layer, and based on the total mass of lithium iron phosphate, the mass ratio of the carbon coating layer is 1.18%.

[0148] 2. Negative electrode sheet The negative electrode sheet includes a negative electrode current collector copper foil, and negative electrode film layers are provided on two surfaces of the copper foil, with a compaction density of 1.56 g / cm 3 , and the coating weight of the single-sided negative electrode film layer is 138 mg / 1540.25 mm 2 , and based on the total mass of the single-sided negative electrode film layer, the negative electrode film layer includes artificial graphite with a mass ratio of 96%, conductive agent carbon black with a mass ratio of 1.1%, binder styrene-butadiene rubber (SBR) with a mass ratio of 1.4%, and thickener sodium carboxymethyl cellulose (CMC-Na) with a mass ratio of 1.5%.

[0149] 3. Electrolyte The electrolyte includes a solvent, an electrolyte salt, and an additive. The solvent includes ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl acetate. The electrolyte salts are lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide (LiFSI). The additives include vinylene carbonate (VC), fluoroethylene carbonate (FEC), ethylene sulfite (ES), and lithium difluoro(oxalato)borate (LiDFOB). Based on the total mass of the electrolyte, the mass ratio of EC is 28.9%, the mass ratio of DMC is 45.4%, the mass ratio of ethyl acetate is 8.3%, the mass ratio of lithium hexafluorophosphate is 8.3%, the mass ratio of LiFSI is 4.2%, the mass ratio of VC is 3%, the mass ratio of FEC is 1%, the mass ratio of ES is 0.5%, and the mass ratio of LiDFOB is 0.5%. The density of the electrolyte is 1.22 g / mL, the viscosity is 3.19 mPa·s, and the conductivity is 11 mS / cm.

[0150] 4. Separator Polypropylene film, with a thickness of 12 μm.

[0151] 5. Battery cell The battery cell includes a housing, a first end cap assembly, a second end cap assembly, an electrode assembly, and an electrolyte. The first end cap assembly and the second end cap assembly are located at both ends in the length direction of the housing. The structure of the first end cap assembly refers to Figure 4 , and the structure of the second end cap assembly refers to Figure 8, that is, the first end - cover assembly and the second end - cover assembly each include an electrode terminal. The electrode assembly and the electrolyte are arranged in the accommodation cavity formed by the housing and the end - cover assembly. The electrode assembly is a laminated electrode assembly, which is made by laminating the above - mentioned positive electrode sheet, separator, and negative electrode sheet. Along the length direction of the electrode assembly, a positive electrode tab extends from one end and a negative electrode tab extends from the other end. The positive electrode tab is electrically connected to the positive terminal, and the negative electrode tab is electrically connected to the negative terminal.

[0152] The length of the battery housing is 245 mm, the width is 104.5 mm, and the thickness is 15.7 mm.

[0153] Performance Test 1. Charging Time Calculate the time for the battery cell to charge from 10% SOC to 80% SOC. The specific charging process is as follows: Charge at a constant current of 1C from 0% SOC to 10% SOC; charge at a constant current of 7.0C from 10% SOC to 30% SOC; charge at a constant current of 6.2C from 30% SOC to 35% SOC; charge at a constant current of 5.7C from 35% SOC to 40% SOC; charge at a constant current of 5.2C from 40% SOC to 45% SOC; charge at a constant current of 4.8C from 45% SOC to 50% SOC; charge at a constant current of 4.6C from 50% SOC to 55% SOC; charge at a constant current of 4.4C from 55% SOC to 60% SOC; charge at a constant current of 4.2C from 60% SOC to 65% SOC; charge at a constant current of 3.9C from 65% SOC to 70% SOC; charge at a constant current of 3.5C from 70% SOC to 75% SOC; charge at a constant current of 3.0C from 75% SOC to 80% SOC. The sum of the total time for each charging segment is the charging time.

[0154] 2. High - temperature Cycle Life At an ambient temperature of 45°C, the battery cell is charged to 3.8V by Step charge, then charged at a constant voltage to 0.05C, left standing for 30 min, discharged at a constant current of 0.5C to 2.5V, and left standing for 30 min. This is one charge - discharge cycle. Repeat the above charge - discharge cycle until the capacity of the battery cell is 80% of the initial capacity. The number of charge - discharge cycles obtained is the high - temperature cycle life of the battery cell.

[0155] The Step charge charging steps are as follows: Charge from 0% SOC to 10% SOC at a constant current of 1C; charge from 10% SOC to 30% SOC at a constant current of 7.0C; charge from 30% SOC to 35% SOC at a constant current of 6.2C; charge from 35% SOC to 40% SOC at a constant current of 5.7C; charge from 40% SOC to 45% SOC at a constant current of 5.2C; charge from 45% SOC to 50% SOC at a constant current of 4.8C; charge from 50% SOC to 55% SOC at a constant current of 4.6C; charge from 55% SOC to 60% SOC at a constant current of 4.4C; charge from 60% SOC to 65% SOC at a constant current of 4.2C; charge from 65% SOC to 70% SOC at a constant current of 3.9C; charge from 70% SOC to 75% SOC at a constant current of 3.5C; charge from 75% SOC to 80% SOC at a constant current of 3.0C; charge from 80% SOC to 100% SOC at a constant current of 0.33C.

[0156] 3. Energy density At 25°C, charge at a constant current of 0.33C to 3.8V, then charge at a constant voltage of 3.8V to 0.05C, and let it stand for 30 min; discharge at a constant current of 0.33C to 2.0V, and record the discharge capacity A at this time 0 , unit: Ah, calculate the discharge platform voltage, unit V; use a caliper to measure the length, width, and height of the battery cell, and calculate the volume V of the single cell 0 , unit: L; the volume energy density VED of the battery cell = (A 0 × discharge platform voltage) ÷ V 0 ÷1000, unit: Wh / L.

[0157] In this application, the length of the battery cell - the size of the positive electrode film layer = 45 mm, the width of the battery cell is 104.5 mm, the thickness of the battery cell is 15.7 mm, and the discharge capacity A 0 is 62.3 Ah, and the discharge platform voltage is 3.2V.

[0158] Example 2 The preparation method of the battery cell is the same as that of Example 1, except that the size of the positive electrode film layer is 400 mm.

[0159] Example 3 The preparation method of the battery cell is the same as that of Example 1, except that the size of the positive electrode film layer is 500 mm.

[0160] Example 4 The preparation method of the battery cell is the same as that of Example 1, except that the size of the positive electrode film layer is 650 mm.

[0161] Example 5 The preparation method of the battery cell is the same as that of Example 1, except that the size of the positive electrode film layer is 700 mm.

[0162] Comparative Example 1 The preparation method of the battery cell was the same as that of Example 1, except that the size of the positive electrode film layer was 150 mm.

[0163] Comparative Example 2 The preparation method of the battery cell was the same as that of Example 1, except that the size of the positive electrode film layer was 800 mm.

[0164] The detailed differences and test results of the battery cells in Examples 2 - 5 and Comparative Examples 1 - 2 are shown in Table 1.

[0165] Table 1

[0166] It can be seen from the comparison between Examples 1 - 5 and Comparative Examples 1 and 2 that by making the size of the positive electrode film layer 200 mm - 700 mm and simultaneously matching with an electrolyte containing chain carboxylic acid ester, the energy density, fast charging performance, and cycling performance of the battery cell can be improved simultaneously. If the size of the positive electrode film layer is too small, although the charging time is short, the energy density of the battery cell is low; if the size of the positive electrode film layer is too large, although the energy density of the battery cell is high, due to the long length of the electrode sheet, the temperature rise of the battery cell is fast and the internal resistance is large, which will shorten the cycling life of the battery cell.

[0167] Example 6 The preparation method of the battery cell was the same as that of Example 4, except that the mass ratio of ethyl acetate was 5%, the mass ratio of EC was 28.9%, and the mass ratio of DMC was 48.6%.

[0168] Example 7 The preparation method of the battery cell was the same as that of Example 4, except that the mass ratio of ethyl acetate was 6.6%, the mass ratio of EC was 28.9%, and the mass ratio of DMC was 47%.

[0169] Example 8 The preparation method of the battery cell was the same as that of Example 4, except that the mass ratio of ethyl acetate was 24.8%, the mass ratio of EC was 28.9%, and the mass ratio of DMC was 28.9%.

[0170] Example 9 The preparation method of the battery cell was the same as that of Example 4, except that the mass ratio of ethyl acetate was 40.8%, the mass ratio of EC was 28.5%, the mass ratio of DMC was 12.2%, and the mass ratio of VC in the additive was 4%.

[0171] Example 10 The preparation method of the battery cell is the same as that of Example 4, except that the mass ratio of ethyl acetate is 56.4%, the mass ratio of EC is 24.2%, the mass ratio of VC in the additive is 5%, and DMC is not included.

[0172] Example 11 The preparation method of the battery cell is the same as that of Example 4, except that the carboxylic acid ester is methyl acetate.

[0173] Comparative Example 3 The preparation method of the battery cell is the same as that of Example 4, except that the mass ratio of ethyl acetate is 61.9%, the mass ratio of EC is 20.6%, and DMC is not included.

[0174] Comparative Example 4 The preparation method of the battery cell is the same as that of Example 4, except that the chain carboxylic acid ester is not included in the electrolyte, the mass ratio of EC is 29.6%, the mass ratio of DMC is 54.9%, and the mass ratio of VC in the additive is 1%.

[0175] The detailed differences and test results of the battery cells in Examples 6 - 11, Comparative Example 3, and Comparative Example 4 are shown in Table 2.

[0176] Table 2

[0177] It can be seen from the comparison between Examples 6 - 10 and Comparative Example 3 and Comparative Example 4 that by adjusting the content of the carboxylic acid ester in the electrolyte, an electrolyte with a higher conductivity can be obtained, thereby shortening the charging time and improving the fast charging performance of the battery. However, when the content of the carboxylic acid ester is too high, gas generation in the electrolyte is likely to be triggered under high-temperature conditions, and acid release corrodes the SEI film, which will reduce the high-temperature cycle life of the battery cell.

[0178] It can be seen from the comparison between Examples 6 - 10 and Comparative Example 1 that the energy density of the battery cell is also improved. It can be seen from the comparison with Comparative Example 2 that the energy density of the battery cell is also improved.

[0179] It can be seen from Example 11 that different types of carboxylic acid esters can all improve the ionic conductivity of the electrolyte.

[0180] Example 12 The preparation method of the battery cell is the same as that of Example 4, except that the compaction density of the positive electrode film layer is 2.5 g / cm 3 .

[0181] Example 13 The preparation method of the battery cell is the same as that of Example 4, except that the compaction density of the positive electrode film layer is 2.6 g / cm 3 .

[0182] Example 14 The preparation method of the battery cell is the same as that of Example 4, except that the compaction density of the positive electrode film layer is 2.7 g / cm 3 .

[0183] Example 15 The preparation method of the battery cell is the same as that of Example 4, except that the coating weight of the positive electrode sheet is 220 mg / 1540.25 mm 2 .

[0184] Example 16 The preparation method of the battery cell is the same as that of Example 4, except that the coating weight of the positive electrode sheet is 260 mg / 1540.25 mm 2 .

[0185] Example 17 The preparation method of the battery cell is the same as that of Example 4, except that the coating weight of the positive electrode sheet is 300 mg / 1540.25 mm 2 .

[0186] Example 18 The preparation method of the battery cell is the same as that of Example 4, except that the coating weight of the positive electrode sheet is 340 mg / 1540.25 mm 2 .

[0187] The detailed differences and test results of the battery cells in Examples 12 - 18 are shown in Table 3.

[0188] Table 3

[0189] It can be seen from Examples 12 - 18 that by adjusting the compaction density and coating weight of the positive electrode film layer, the charging time and energy density of the battery cell can be optimized, and a battery cell with both excellent fast charging performance and high energy density can be obtained.

[0190] Example 19 The preparation method of the battery cell is the same as that of Example 4, except that the lithium supplement agent is lithium nickelate.

[0191] Example 20 The preparation method of the battery cell is the same as that of Example 4, except that the mass ratio of Li 5 FeO 4 is 0.5%, and the mass ratio of the lithium iron phosphate material is 96.2%.

[0192] Example 21 The preparation method of the battery cell is the same as that of Example 4, except that the mass ratio of Li 5 FeO 4The mass ratio is 1.5%, and the mass ratio of the lithium iron phosphate material is 95.2%.

[0193] Example 22 The preparation method of the battery cell is the same as that of Example 4, except that the mass ratio of Li 5 FeO 4 is 2.5%, and the mass ratio of the lithium iron phosphate material is 94.2%.

[0194] Example 23 The preparation method of the battery cell is the same as that of Example 4, except that the mass ratio of Li 5 FeO 4 is 2.8%, and the mass ratio of the lithium iron phosphate material is 93.9%.

[0195] The detailed differences and test results of the battery cells in Examples 19 - 23 are shown in Table 4.

[0196] Table 4

[0197] It can be seen from Examples 20 - 23 that by adjusting the content of the lithium supplement agent in the positive electrode film layer, the charging time, cycle life, and energy density of the battery cell can be optimized simultaneously, and a battery cell with excellent comprehensive performance can be obtained.

[0198] It can be seen from Example 19 that different types of lithium supplement agents can all play the role of lithium supplementation.

[0199] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered within the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, comprising a housing, an electrode assembly and an electrolyte, wherein the electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator between the positive electrode sheet and the negative electrode sheet, wherein: The positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer, the positive electrode current collector comprises a positive electrode main body and a positive electrode ear portion, the positive electrode ear portion extends from the positive electrode main body portion, the positive electrode film layer is located on at least one side of the positive electrode main body portion, the positive electrode film layer comprises a lithium-containing phosphate, and the size of the positive electrode film layer along the length direction of the positive electrode sheet is 200 mm-700 mm; The negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer, the negative electrode current collector comprises a negative electrode main body and a negative electrode ear portion, the negative electrode ear portion extends from the negative electrode main body, the negative electrode film layer is located on at least one side of the positive electrode main body, and the negative electrode film layer comprises graphite; The electrolyte includes chain carboxylic acid ester, and based on the total mass of the electrolyte, the mass proportion of the chain carboxylic acid ester is 5%-50%.

2. The battery cell according to claim 1, wherein: Along the length direction of the positive electrode plate, the size of the positive electrode film layer is 400mm-650mm.

3. The battery cell according to claim 1, wherein: Based on the total mass of the electrolyte, the mass proportion of the chain carboxylic acid ester is 8%-30%.

4. The battery cell according to claim 1, wherein: The conductivity of the electrolyte at room temperature is 9.5 mS / cm-19 mS / cm.

5. The battery cell according to claim 1, wherein: The conductivity of the electrolyte at room temperature is 9.7 mS / cm-13.5 mS / cm.

6. The battery cell according to claim 1, wherein: The viscosity of the electrolyte at room temperature is 2mPa·s-5mPa·s.

7. The battery cell according to claim 1, wherein: The density of the electrolyte at room temperature is 1.05 g / mL-1.35 g / mL.

8. The battery cell according to claim 1, wherein: The chain carboxylic acid ester includes a compound shown in Formula I: Formula I, Wherein, R1 includes one or more of a hydrogen atom, a C1-C5 alkyl group, and a C1-C5 haloalkyl group, and R2 includes one or more of a C1-C5 alkyl group, and a C1-C5 haloalkyl group.

9. The battery cell according to claim 8, wherein: R1 includes one or more of a hydrogen atom, a C1-C3 alkyl group, and a C1-C3 haloalkyl group; and / or R2 includes one or more of C1-C3 alkyl and C1-C3 haloalkyl.

10. The battery cell according to claim 1, wherein: The chain carboxylic acid ester includes Formula I-1, Formula I-2, Formula I-3, Formula I-4, Formula I-5, Formula I-6, Formula I-7, One or more of formula I-8.

11. The battery cell according to claim 1, wherein: The single-sided coating weight of the positive electrode film layer is 200 mg / 1540.25 mm 2 -340mg / 1540.25mm 2 .

12. The battery cell according to claim 1, wherein: The single-sided coating weight of the positive electrode film layer is 240 mg / 1540.25 mm 2 -300mg / 1540.25mm 2 .

13. The battery cell according to claim 1, wherein: When the battery cell is at 100% SOC, the compaction density of the positive electrode film layer is 2.5 g / cm 3 -2.8g / cm 3 .

14. The battery cell according to claim 1, wherein: The lithium-containing phosphate includes at least one of a lithium iron phosphate material and a lithium iron manganese phosphate material.

15. The battery cell according to claim 1, wherein: The positive electrode film layer also includes a lithium supplement agent, and based on the total mass of the positive electrode film layer, the mass proportion of the lithium supplement agent is 0.5%-2.5%.

16. The battery cell according to claim 15, wherein: The lithium supplement includes one or more of lithium nickel cobalt manganese oxide, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium metasilicate, lithium metamanganate, lithium tartrate, trilithium citrate, lithium nickel oxide, and lithium ferrite.

17. The battery cell according to claim 1, wherein: The positive electrode sheet and the negative electrode sheet are stacked.

18. The battery cell according to claim 1, wherein: The battery cell comprises a shell, a first end cap assembly and a second end cap assembly, wherein the shell, the first end cap assembly and the second end cap assembly define a receiving cavity, the first end cap assembly comprises a first end cap and at least one positive terminal, and the positive electrode body is electrically connected to the positive electrode terminal through the positive electrode ear; and / or, The second end cap assembly includes a second end cap and at least one negative terminal, and the negative electrode body is electrically connected to the negative electrode terminal through the negative electrode ear.

19. The battery cell according to claim 18, wherein: The first end cap assembly includes a positive terminal and a negative terminal, the positive electrode body is electrically connected to the positive terminal through the positive electrode ear, and the negative electrode body is electrically connected to the negative terminal through the negative electrode ear; and / or, The second end cap assembly includes a positive terminal and a negative terminal, the positive electrode body is electrically connected to the positive terminal through the positive electrode ear, and the negative electrode body is electrically connected to the negative terminal through the negative electrode ear.

20. The battery cell according to claim 19, wherein: The first end cover assembly and the second end cover assembly are arranged at two ends of the shell, and in the length direction of the battery cell, the electrode terminals of the same polarity on the first end cover assembly and the second end cover assembly are staggered.

21. The battery cell according to claim 20, wherein: The electrode terminals of the same polarity are arranged diagonally along the length direction of the battery cell.

22. The battery cell according to any one of claims 1 to 21, wherein: The battery cells are configured to be charged from 10% SOC to 80% SOC in a charging time of 5 min to 10.5 min.

23. A battery device, wherein: Comprising the battery monomer described in any one of claims 1-22, the battery device is at least one of a battery module, a battery pack, and an energy storage device.

24. An electrical device, wherein: The invention comprises the battery cell according to any one of claims 1 to 22 or the battery device according to claim 23, wherein the battery cell or the battery device is used to provide electrical energy.

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