Battery cell, electrolyte additive and preparation method therefor, battery device, and electric device

Abstract

The present application provides a battery cell, an electrolyte additive, an electrolyte additive preparation method, a battery device, and an electric device. The battery cell of the present application comprises an electrolyte, a positive electrode sheet, and a negative electrode sheet; the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer located on at least one side of the positive electrode current collector; and the electrolyte comprises a compound represented by formula I. The battery cell of the present application has reduced cycle gas production, and prolonged cycle life.

Description

Battery cells, electrolyte additives and their preparation methods, battery devices and electrical devices

[0001] This application is based on and claims priority to CN application number 202411715023.0, filed on November 27, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a battery cell, an electrolyte additive, a method for preparing the electrolyte additive, a battery device, and an electrical device. Background Technology

[0003] In recent years, with the increasingly wide range of applications, batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace, and many other fields. Due to the significant advancements in battery technology, higher requirements have been placed on their high-temperature cycle life and other aspects. Summary of the Invention

[0004] This application was made in view of the above-mentioned problems, and its object is to provide a battery cell, an electrolyte additive, a method for preparing the electrolyte additive, a battery device, and an electrical device. The battery cell of this application exhibits reduced cycle gas production and improved cycle life.

[0005] To achieve the above objectives, a first aspect of this application provides a battery cell comprising an electrolyte, a positive electrode, and a negative electrode. The positive electrode includes a positive current collector and a positive electrode film layer located on at least one side of the positive current collector. The electrolyte comprises a compound represented by Formula I.

[0006] in,

[0007] A is selected from elements N and S;

[0008] R1 is independently selected from C 1-6 Alkyl, C 2-6 alkenyl, C 2-6 alkynyl group;

[0009] R2 does not exist or R2 is selected from C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2-6 alkynyl, halogenated C 2-6 alkynyl group;

[0010] R3 is selected from C 1-6 Alkyl, Halogenated C1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2- 6-Alkyne, Halogenated C 2-6 Alkyne group.

[0011] Therefore, the compound of this application is reduced on the surface of the positive electrode to form a CEI film with good flexibility, high density and / or high stability, which inhibits the oxidative decomposition of electrolyte components on the surface of the positive electrode under high temperature and high pressure, improves the structural stability of the positive electrode active material, thereby reducing the amount of gas generated during the cycle of the battery cell and improving the cycle life of the battery cell.

[0012] In any implementation, R1 is independently selected from C. 2-6 alkenyl, C 2-6 Alkyne group.

[0013] In any implementation, R1 is independently selected from C. 2-6 Alkenyl group.

[0014] In any implementation, R1 is independently selected from C. 2-4 Alkenyl group.

[0015] In any embodiment, R1 is independently selected from vinyl, allyl, and 1-propenyl.

[0016] In any implementation, R2 is absent or R2 is selected from halogenated C. 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 Alkyne group.

[0017] In any implementation, R2 is absent or R2 is selected from halogenated C. 1-6 alkyl.

[0018] In any embodiment, R2 is absent or R2 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms.

[0019] In any embodiment, R2 is absent or R2 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl.

[0020] In any embodiment, R2 is absent or R2 is selected from 3-fluoropropyl, 3,3-difluoropropyl, or 3,3,3-trifluoropropyl.

[0021] In any implementation, R3 is selected from halogenated C. 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6Alkyne group.

[0022] In any implementation, R3 is selected from halogenated C. 1-6 alkyl.

[0023] In any embodiment, R3 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms.

[0024] In any embodiment, R3 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl.

[0025] In any embodiment, R3 is selected from 3-fluoropropyl, 3,3-difluoropropyl, and 3,3,3-trifluoropropyl.

[0026] In any embodiment, the compound is selected from:

[0027] Therefore, the flexibility, density and / or stability of the CEI film formed on the surface of the positive electrode by the specific compounds mentioned above in this application are further improved, and the structural stability of the positive electrode active material is further improved, thereby reducing the amount of gas generated during the cycle of the battery cell and improving the cycle life of the battery cell.

[0028] In any embodiment, the positive electrode film layer includes one or more of the following: halogens, phosphorus (P), nitrogen (N), sulfur (S), Li3N, Li3P, lithium halides, and lithium sulfides. This demonstrates that the compounds of this application form a flexible, dense, and / or stable CEI film on the surface of the positive electrode film layer, inhibiting the oxidative decomposition of electrolyte components on the positive electrode sheet and suppressing irreversible structural changes of the positive electrode active material under high temperature and high pressure, thereby improving the structural stability of the positive electrode active material.

[0029] In any embodiment, the positive electrode film layer includes a characteristic element layer located on the side of the positive electrode film layer away from the positive electrode current collector, and the characteristic element layer includes N or S elements.

[0030] This demonstrates that the compound of this application forms a CEI film on the surface of the positive electrode film, which can suppress the oxidative decomposition of the positive electrode surface and the irreversible structural changes of the positive electrode active material under high temperature and high pressure, thereby improving the structural stability of the positive electrode active material, reducing the cycle gas production of the battery cell, and improving the cycle life of the battery cell.

[0031] In any embodiment, the thickness of the characteristic element layer is 1nm-10nm or 3nm-7nm. Thus, on the one hand, the characteristic element layer of the aforementioned thickness helps to suppress the oxidative decomposition of the positive electrode surface, improve the structural stability of the positive electrode active material, reduce the amount of gas generated during battery cell cycles, and increase cycle life; on the other hand, it allows the battery cell to maintain a high energy density.

[0032] In any embodiment, the compound has a mass content of 1%-8% or 3%-5% in the electrolyte. Therefore, on the one hand, the above-mentioned compound content is beneficial for forming a CEI film on the surface of the positive electrode, thereby reducing the amount of gas generated during battery cell cycling; on the other hand, it is beneficial for suppressing the side reactions between the compound and the negative electrode, thereby improving the cycle performance of the battery cell.

[0033] In any embodiment, the battery cell is formed by one or more of the following operations: discharging the battery cell at 1C-3C to 1V-2V, letting it stand for 1min-20min, and then discharging it at 0.1C-1C to 1V-2V.

[0034] In any embodiment, the battery cell is formed by one or more of the following operations: discharging the battery cell at 1C-2C to 1.5V-1.9V, letting it stand for 5min-10min, and then discharging it at 0.2C-0.7C to 1.5V-1.9V.

[0035] The formation method of high current short-time discharge to low potential is beneficial for the compounds of this application to form a CEI film with good flexibility, high density and / or high stability on the surface of the positive electrode, so as to inhibit the oxidative decomposition of electrolyte components on the surface of the positive electrode and improve the structural stability of the positive electrode active material, thereby reducing the cycle gas production of the battery cell and improving the cycle life of the battery cell.

[0036] In any embodiment, the battery cell includes one or more of lithium metal battery cells and lithium-ion battery cells.

[0037] The second aspect of this application provides an electrolyte additive of Formula I.

[0038] in,

[0039] A is selected from elements N and S;

[0040] R1 is independently selected from C 1-6 Alkyl, C 2-6 alkenyl, C 2-6 alkynyl group;

[0041] R2 does not exist or R2 is selected from C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6alkenyl, halogenated C 2-6 alkenyl, C 2-6 alkynyl, halogenated C 2-6 alkynyl group;

[0042] R3 is selected from C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2- 6-Alkyne, Halogenated C 2-6 Alkyne group.

[0043] Therefore, the electrolyte additives of this application are reduced on the surface of the positive electrode to form a CEI film with good flexibility, high density and / or high stability, which inhibits the oxidative decomposition of electrolyte components on the surface of the positive electrode under high temperature and high pressure, improves the structural stability of the positive electrode active material, thereby reducing the amount of gas generated during the cycle of the battery cell and improving the cycle life of the battery cell.

[0044] In any implementation, R1 is independently selected from C. 2-6 alkenyl, C 2-6 Alkyne group.

[0045] In any implementation, R1 is independently selected from C. 2-6 Alkenyl group.

[0046] In any implementation, R1 is independently selected from C. 2-4 Alkenyl group.

[0047] In any embodiment, R1 is independently selected from vinyl, allyl, and 1-propenyl.

[0048] In any implementation, R2 is absent or R2 is selected from halogenated C. 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 Alkyne group.

[0049] In any implementation, R2 is absent or R2 is selected from halogenated C. 1-6 alkyl.

[0050] In any embodiment, R2 is absent or R2 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms.

[0051] In any embodiment, R2 is absent or R2 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl.

[0052] In any embodiment, R2 is absent or R2 is selected from 3-fluoropropyl, 3,3-difluoropropyl, or 3,3,3-trifluoropropyl.

[0053] In any implementation, R3 is selected from halogenated C. 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 Alkyne group.

[0054] In any implementation, R3 is selected from halogenated C. 1-6 alkyl.

[0055] In any embodiment, R3 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms.

[0056] In any embodiment, R3 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl.

[0057] In any embodiment, R3 is selected from 3-fluoropropyl, 3,3-difluoropropyl, and 3,3,3-trifluoropropyl.

[0058] In any embodiment, the electrolyte additive is selected from:

[0059] The third aspect of this application provides a method for preparing the above-mentioned electrolyte additive, which is either method one or method two;

[0060] Method 1 includes the following steps:

[0061] The compound shown in Formula A, the compound shown in Formula B, and the compound shown in Formula C are reacted in a solvent to obtain the compound shown in Formula I-1;

[0062] The second method includes the following steps:

[0063] The compound shown in Formula A is reacted with the compound shown in Formula D in a solvent to obtain the compound shown in Formula I-2;

[0064] The definitions of R1, R2, and R3 are as described above; X is selected from halogens.

[0065] The fourth aspect of this application provides a battery device, including a battery cell according to the first aspect of this application, an electrolyte additive according to the second aspect of this application, or an electrolyte additive prepared by the method according to the third aspect of this application.

[0066] The fifth aspect of this application provides an electrical device, including a battery cell of the first aspect of this application or a battery device of the fourth aspect of this application. Attached Figure Description

[0067] Figure 1 is a schematic diagram of a battery cell according to one embodiment of this application.

[0068] Figure 2 is an exploded view of a battery cell according to an embodiment of this application shown in Figure 1.

[0069] Figure 3 is a schematic diagram of a battery module according to one embodiment of this application.

[0070] Figure 4 is a schematic diagram of a battery pack according to one embodiment of this application.

[0071] Figure 5 is an exploded view of the battery pack of one embodiment of this application shown in Figure 4.

[0072] Figure 6 is a schematic diagram of an electrical device in which a single battery cell is used as a power source according to an embodiment of this application.

[0073] Figure 7 shows a SEM image of the positive electrode sheet of the battery cell in Example 1 after 200 cycles.

[0074] Figure 8 shows the SEM image of the positive electrode of the single cell in Comparative Example 1 after 60 cycles.

[0075] Explanation of reference numerals in the attached diagram: 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Battery cell; 51 Housing; 52 Electrode assembly; 53 Top cover assembly. Detailed Implementation

[0076] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the battery cell, battery module, battery pack, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0077] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0078] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0079] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0080] Unless otherwise specified, "alkyl" in this application refers to a group obtained by removing one hydrogen atom from a straight-chain or branched saturated alkane. For example, "C 1-6 Alkyl", C 1-4 Alkyl", C 1- 3-alkyl", C 1-2 Alkyl groups, etc., specific examples include but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, 2-methylbutyl, neopentyl, 1-ethylpropyl, n-hexyl, isohexyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,3-dimethylbutyl, 2-ethylbutyl, 1,2-dimethylpropyl, etc.

[0081] Unless otherwise specified, "alkenyl" in this application refers to a group obtained by removing one hydrogen atom from a straight-chain or branched hydrocarbon containing at least one carbon-carbon double bond. For example, "C 2-6 "alkenyl", "C" 2-4 Examples of these include, but are not limited to, vinyl, 1-propenyl, 2-propenyl, allyl, 1-butenyl, 2-butenyl, etc.

[0082] Unless otherwise specified, "alkynyl" in this application refers to a group obtained by removing one hydrogen atom from a straight-chain or branched hydrocarbon containing at least one carbon-carbon triple bond. This includes, for example, "C..." 2-6 "Alkyne", "C" 2-4 Examples of "alkynyl" include, but are not limited to: ethynyl, 1-propynyl, 1-butyn-1-yl, 1-butyn-3-yl, 1-butyn-4-yl, 2-butynyl, 1,3-butadiynyl, 1-pentyn-1-yl, 2-pentyn-1-yl, 3-pentyn-1-yl, etc.

[0083] Unless otherwise specified, "halogen" in this application refers to F, Cl, Br or I.

[0084] Unless otherwise specified, "halogenated alkyl" in this application refers to a group in which at least one hydrogen atom of an alkyl group is substituted by a halogen. The definitions of alkyl and halogen are as described above. For example, "halogenated C..." 1-6 Alkyl group, halogenated C 1-4 Alkyl group, halogenated C 1-3 Alkyl group, halogenated C 1-2 Alkyl groups, etc., specific examples include but are not limited to: monofluoromethyl, difluoromethyl, trifluoromethyl, 1-fluoroethyl, 1,1-difluoroethyl, 2,2,2-trifluoroethyl, 1-fluoropropyl, 2,2-difluoropropyl, 3-fluoropropyl, 3,3-difluoropropyl, 3,3,3-trifluoropropyl, etc.

[0085] Unless otherwise specified, "halogenated alkenyl" in this application refers to a group in which at least one hydrogen atom of the alkenyl group is replaced by a halogen. The definitions of alkenyl and halogen are as described above. For example, "halogenated C..." 2-6 "Alkenyl", "halogenated C" 2-4 Examples of "alkenyl" include, but are not limited to: 1-fluorovinyl, 1,1-difluorovinyl, 1,2-difluorovinyl, 1-fluoro-1-propenyl, 2-fluoro-1-propenyl, 1,1-difluoro-1-propenyl, 1,2-difluoro-1-propenyl, etc.

[0086] Unless otherwise specified, "halogenated alkynyl" in this application refers to a group in which at least one hydrogen atom of the alkynyl group is replaced by a halogen. The definitions of alkynyl and halogen are as described above. This includes, for example, "halogenated C..." 2-6 "Alkyne group", "halogenated C" 2-4 Examples of "alkynyl" include, but are not limited to: 1-fluoroethynyl, 3-fluoro-1-propynyl, 3,3-difluoro-1-propynyl, 1-fluoro-3-propynyl, 3-fluoro-3-propynyl, 1,3-difluoro-3-propynyl, etc.

[0087] Unless otherwise specified, "lithium halide" in this application refers to compounds formed by lithium and halogens, such as LiF, LiCl, LiBr, LiI, etc.

[0088] Unless otherwise specified, "lithium sulfide" in this application refers to compounds formed by lithium and sulfur, such as Li2S.

[0089] [Battery cell]

[0090] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0091] The battery cells can be lithium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, etc.

[0092] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0093] Conventional electrolyte components in lithium metal batteries (such as ether solvents) are prone to oxidative decomposition on the surface of the positive electrode under high temperature and pressure, which damages the structural stability of the positive electrode active material. Furthermore, the positive electrode active material is susceptible to irreversible crystal structure changes under high temperature and pressure, leading to increased gas production and decreased cycle life in the battery cell. Therefore, it is necessary to improve the stability of the interface between the positive electrode and the electrolyte to address the technical problems of increased gas production and decreased cycle life in the battery cell caused by the above reasons.

[0094] To address the aforementioned technical problems, one embodiment of this application provides a battery cell comprising an electrolyte, a positive electrode, and a negative electrode. The positive electrode includes a positive current collector and a positive electrode film layer located on at least one side of the positive current collector. The electrolyte comprises a compound represented by Formula I.

[0095] in,

[0096] A is selected from elements N and S;

[0097] R1 is independently selected from C 1-6 Alkyl, C 2-6 alkenyl, C 2-6 alkynyl group;

[0098] R2 does not exist or R2 is selected from C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2-6 alkynyl, halogenated C 2-6 alkynyl group;

[0099] R3 is selected from C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2- 6-Alkyne, Halogenated C 2-6 Alkyne group.

[0100] As a result, the applicant unexpectedly discovered that during the formation process of the battery cell, the compound of this application is reduced on the surface of the positive electrode to form a CEI film with good flexibility, high density and / or high stability, which inhibits the oxidative decomposition of electrolyte components on the surface of the positive electrode under high temperature and high pressure, improves the structural stability of the positive electrode active material, and inhibits the irreversible crystal structure change of the positive electrode active material under high temperature and high pressure, thereby reducing the amount of gas generated during the cycle charge and discharge process of the battery cell and improving the cycle life of the battery cell.

[0101] In some implementations, R1 is independently selected from C. 2-6 alkenyl, C 2-6 Alkyne group.

[0102] In some implementations, R1 is independently selected from C. 2-6 Alkenyl group.

[0103] In some implementations, R1 is independently selected from C. 2-4 Alkenyl group.

[0104] In some embodiments, R1 is independently selected from vinyl, allyl, and 1-propenyl.

[0105] In some implementations, R2 is absent or R2 is selected from halogenated C. 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 Alkyne group.

[0106] In some implementations, R2 is absent or R2 is selected from halogenated C. 1-6 alkyl.

[0107] In some embodiments, R2 is absent or R2 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms.

[0108] In some embodiments, R2 is absent or R2 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl.

[0109] In some embodiments, R2 is absent or R2 is selected from 3-fluoropropyl, 3,3-difluoropropyl, or 3,3,3-trifluoropropyl.

[0110] In some implementations, R3 is selected from halogenated C 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 Alkyne group.

[0111] In some implementations, R3 is selected from halogenated C 1-6 alkyl.

[0112] In some embodiments, R3 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms.

[0113] In some embodiments, R3 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl.

[0114] In some embodiments, R3 is selected from 3-fluoropropyl, 3,3-difluoropropyl, and 3,3,3-trifluoropropyl.

[0115] In some embodiments, the compound is selected from:

[0116] Therefore, the flexibility, density and / or stability of the CEI film formed on the surface of the positive electrode by the specific compounds mentioned above in this application are further improved, and the structural stability of the positive electrode active material is further improved, thereby reducing the amount of gas generated during the cycle of the battery cell and improving the cycle life of the battery cell.

[0117] In some embodiments, the positive electrode film layer includes one or more of the following: halogens, phosphorus (P), nitrogen (N), sulfur (S), Li3N, Li3P, lithium halides, and lithium sulfides. This demonstrates that the compounds of this application form a flexible, dense, and / or stable CEI film on the surface of the positive electrode film layer, inhibiting the oxidative decomposition of electrolyte components on the positive electrode sheet and suppressing irreversible structural changes of the positive electrode active material under high temperature and high pressure, thereby improving the structural stability of the positive electrode active material.

[0118] In some embodiments, the positive electrode film layer includes a characteristic element layer located on the side of the positive electrode film layer away from the positive electrode current collector, and the characteristic element layer includes N or S elements.

[0119] This demonstrates that the compound of this application forms a CEI film on the surface of the positive electrode film, which can suppress the oxidative decomposition of the positive electrode surface and the irreversible structural changes of the positive electrode active material under high temperature and high pressure, thereby improving the structural stability of the positive electrode active material, reducing the cycle gas production of the battery cell, and improving the cycle life of the battery cell.

[0120] In some embodiments, the thickness of the characteristic element layer is 1nm-10nm or 3nm-7nm, for example, 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm or any range of the above values. Thus, on the one hand, the characteristic element layer of the above thickness helps to suppress the oxidative decomposition of the positive electrode surface, improve the structural stability of the positive electrode active material, reduce the gas generation of the battery cell during cycle, and improve cycle life; on the other hand, it allows the battery cell to maintain a high energy density.

[0121] In some embodiments, the compound is present in the electrolyte at a mass content of 1%-8% or 3%-5%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or any range of the above values. Thus, on the one hand, the above-mentioned compound content facilitates the formation of a CEI film on the surface of the positive electrode, reducing the amount of gas generated during battery cell cycling; on the other hand, it helps suppress side reactions between the compound and the negative electrode, thereby improving the cycle performance of the battery cell.

[0122] In some embodiments, the battery cell is formed using one or more of the following operations: discharging the battery cell at 1C-3C (e.g., 1C, 1.5C, 2C, 2.5C, 3C, or any combination thereof) to 1V-2V (e.g., 1V, 1.1V, 1.2V, 1.3V, 1.4V, 1.5V, 1.6V, 1.7V, 1.8V, 1.9V, 2V, or any combination thereof), and then allowing it to stand for 1min-20min (e.g., 1min, 2min, 4min, 5min, 6min, 7min, 8min, 10min). 12 min, 14 min, 15 min, 16 min, 17 min, 18 min, 20 min or any range of the above values), then discharge at 0.1C-1C (e.g. 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 0.6C, 0.7C, 0.8C, 0.9C, 1C or any range of the above values) to 1V-2V (e.g. 1V, 1.1V, 1.2V, 1.3V, 1.4V, 1.5V, 1.6V, 1.7V, 1.8V, 1.9V, 2V or any range of the above values).

[0123] In some embodiments, the battery cell is formed by one or more of the following operations: discharging the battery cell at 1C-2C to 1.5V-1.9V, letting it stand for 5min-10min, and then discharging it at 0.2C-0.7C to 1.5V-1.9V.

[0124] The high-current, short-duration discharge to low potential formation method is beneficial for the formation of a flexible, dense, and / or stable CEI film on the surface of the positive electrode, thereby inhibiting the oxidative decomposition of electrolyte components on the positive electrode surface and improving the structural stability of the positive electrode active material. This reduces the cycle gas generation of the battery cell and improves the cycle life of the battery cell. Specifically, the first stage of discharge to low potential in the above operation can suppress excessive lithium intercalation in the positive electrode film. During the resting process of the above operation, a voltage rebound is prone to occur. The second stage of discharge to low potential promotes the formation of the CEI film on the surface of the positive electrode.

[0125] In some embodiments, the battery cell includes one or more of lithium metal battery cells and lithium-ion battery cells.

[0126]

Positive Electrode

[0127] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector.

[0128] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0129] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0130] In some embodiments, the positive electrode film layer includes a positive electrode active material.

[0131] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0132] In some embodiments, the positive electrode active material includes one or more of lithium nickel cobalt manganese oxide, lithium iron phosphate, and lithium manganese iron phosphate.

[0133] During the charging and discharging process of a battery, Li undergoes insertion / extraction and consumption, resulting in varying molar Li content at different discharge states. In the examples of cathode materials in this application, the molar Li content refers to the initial state of the material, i.e., the state before feeding. When the cathode material is applied to the battery system, the molar Li content changes after charge-discharge cycles.

[0134] In the examples of cathode materials in this application, the molar content of O is only a theoretical value. Oxygen release from the crystal lattice will cause changes in the molar content of oxygen, and the actual molar content of O will fluctuate.

[0135] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0136] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0137] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0138] [Negative electrode plate]

[0139] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0140] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0141] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0142] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0143] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an 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 lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0144] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0145] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0146] In some embodiments, the negative electrode film layer may optionally include a binder. As an example, 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).

[0147] In some embodiments, the negative electrode film may optionally include a conductive agent. As an example, 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.

[0148] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0149] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0150] Electrolytes

[0151] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0152] Liquid electrolytes include electrolyte salts and solvents.

[0153] In some embodiments, the electrolyte salt may be selected from 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 difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0154] In some embodiments, the solvent may be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ethers. The solvent may also be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0155] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0156] The present invention also provides an electrolyte additive represented by Formula I.

[0157] in,

[0158] A is selected from elements N and S;

[0159] R1 is independently selected from C 1-6 Alkyl, C 2-6 alkenyl, C 2-6 alkynyl group;

[0160] R2 does not exist or R2 is selected from C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6alkenyl, C 2-6 alkynyl, halogenated C 2-6 alkynyl group;

[0161] R3 is selected from C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2- 6-Alkyne, Halogenated C 2-6 Alkyne group.

[0162] In some implementations, R1 is independently selected from C. 2-6 alkenyl, C 2-6 Alkyne group.

[0163] In some implementations, R1 is independently selected from C. 2-6 Alkenyl group.

[0164] In some implementations, R1 is independently selected from C. 2-4 Alkenyl group.

[0165] In some embodiments, R1 is independently selected from vinyl, allyl, and 1-propenyl.

[0166] In some implementations, R2 is absent or R2 is selected from halogenated C. 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 Alkyne group.

[0167] In some implementations, R2 is absent or R2 is selected from halogenated C. 1-6 alkyl.

[0168] In some embodiments, R2 is absent or R2 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms.

[0169] In some embodiments, R2 is absent or R2 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl.

[0170] In some embodiments, R2 is absent or R2 is selected from 3-fluoropropyl, 3,3-difluoropropyl, or 3,3,3-trifluoropropyl.

[0171] In some implementations, R3 is selected from halogenated C 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 Alkyne group.

[0172] In some implementations, R3 is selected from halogenated C1-6 alkyl.

[0173] In some embodiments, R3 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms.

[0174] In some embodiments, R3 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl.

[0175] In some embodiments, R3 is selected from 3-fluoropropyl, 3,3-difluoropropyl, and 3,3,3-trifluoropropyl.

[0176] In some embodiments, the electrolyte additive is selected from:

[0177] This application also provides a method for preparing the above-mentioned electrolyte additive, which is either method one or method two;

[0178] Method 1 includes the following steps:

[0179] The compound shown in Formula A, the compound shown in Formula B, and the compound shown in Formula C are reacted in a solvent to obtain the compound shown in Formula I-1;

[0180] The second method includes the following steps:

[0181] The compound shown in Formula A is reacted with the compound shown in Formula D in a solvent to obtain the compound shown in Formula I-2;

[0182] The definitions of R1, R2, and R3 are as described above; X is selected from halogens.

[0183] In some embodiments, the reaction is carried out in the presence of a catalyst in either method one or method two.

[0184] In some embodiments, in method one or method two, the catalyst includes one or more of phenyl diselenide, dimethyl selenide, dimethyl diselenide, and diphenyl diselenide.

[0185] In some embodiments, in method one or method two, the reaction temperature is 50℃-90℃, for example, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃ or any range of the above values, and / or, the reaction time is 36-96 hours, for example, 36 hours, 40 hours, 42 hours, 45 hours, 48 ​​hours, 50 hours, 52 hours, 55 hours, 56 hours, 58 hours, 60 hours, 62 hours, 64 hours, 65 hours, 68 hours, 70 hours, 72 hours, 74 hours, 76 hours, 78 hours, 80 hours, 82 hours, 84 hours, 85 hours, 86 hours, 88 hours, 90 hours, 92 hours, 94 hours, 95 hours, 96 hours or any range of the above values.

[0186] In some embodiments, in method one or method two, the reaction is carried out in an inert atmosphere; optionally, the inert atmosphere includes at least one of nitrogen, helium, neon, argon, krypton, and xenon.

[0187] In some embodiments, in method one or method two, the solvent includes at least one of acetonitrile, methylamine, triethylamine, and water.

[0188] In some embodiments, method one or method two further includes: mixing the reaction product with a saturated sodium chloride solution, diluting, drying to remove water, removing impurities, concentrating, and purifying.

[0189] In some embodiments, ethyl acetate is used for dilution in method one or method two.

[0190] In some embodiments, in method one or method two, anhydrous sodium sulfate is used for drying and dehydration.

[0191] In some implementations, impurities are removed by filtering in either method one or method two.

[0192] In some embodiments, concentration is performed by rotary evaporation in either method one or method two.

[0193] In some embodiments, purification is performed by column chromatography in method one or method two; optionally, n-hexane-ethyl acetate is used as the eluent.

[0194] As an example, gel electrolytes include polymers as a backbone network and can be used in conjunction with ionic liquids—lithium salts.

[0195] As an example, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0196] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0197] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium-germanium-phosphorus-sulfur, sulfosilium-germanium), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0198] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0199]

Isolation Components

[0200] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0201] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0202] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. 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. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0203] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0204] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0205] [Structure of the Electrode Assembly]

[0206] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0207] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0208] In some implementations, the electrode assembly is a stacked structure.

[0209] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0210] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0211] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0212] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0213] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0214] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0215] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0216]

shell

[0217] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0218] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0219] In some embodiments, the housing includes an end cap and a housing, the housing having an opening, and the end cap covering the opening. The housing may have one or more openings. The end cap may also have one or more.

[0220] Electrode terminals

[0221] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0222] Pressure relief mechanism

[0223] In some embodiments, a pressure relief mechanism is provided on the casing. The pressure relief mechanism is used to release the internal gas of the battery cell.

[0224] As an example, the internal pressure or temperature of a battery cell is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief mechanism is activated or a weak structure in the pressure relief mechanism is broken, thereby creating an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell.

[0225] As an example, the pressure relief mechanism can be integrally molded with the housing.

[0226] As an example, the pressure relief mechanism can also be separately installed and connected to the housing.

[0227] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure and temperature of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to: movement of components within the mechanism to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the mechanism, etc. When the pressure relief mechanism is activated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the activated portion. This method allows for pressure and temperature relief of the battery cell under controllable pressure or temperature, thereby preventing potentially more serious accidents.

[0228] In some embodiments, when the housing is a non-sealed structure, the pressure relief mechanism can be configured as a through hole for venting gas inside the battery cell.

[0229] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0230] [Battery Device]

[0231] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0232] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0233] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0234] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0235] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0236] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0237] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0238] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0239] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0240] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0241] For example, Figure 1 shows a square-structured battery cell 5 as an example.

[0242] In some embodiments, referring to FIG2, the outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be placed over the opening to close the receiving cavity. The positive electrode sheet, negative electrode sheet, and separator may be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the battery cell 5 may be one or more, which can be selected by those skilled in the art according to specific practical needs.

[0243] In some implementations, individual battery cells can be assembled into a battery module. The number of individual battery cells contained in a battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0244] Figure 3 shows a battery module 4 as an example. Referring to Figure 3, in the battery module 4, multiple battery cells 5 can be arranged sequentially along the length of the battery module 4. Of course, they can also be arranged in any other manner. Furthermore, the multiple battery cells 5 can be fixed in place using fasteners.

[0245] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple battery cells 5 are received.

[0246] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0247] Figures 4 and 5 show a battery pack 1 as an example. Referring to Figures 4 and 5, the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper box 2 and a lower box 3, with the upper box 2 covering the lower box 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0248] In addition, this application also provides an electrical device, which includes at least one of the battery cell, battery module, or battery pack provided in this application. The battery cell, battery module, or battery pack can be used as the power source of the electrical device or as the energy storage unit of the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0249] As an electrical device, you can choose individual battery cells, battery modules, or battery packs according to your usage requirements.

[0250] Figure 6 shows an example of an electrical device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the individual battery cells, a battery pack or battery module can be used.

[0251] [Example]

[0252] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0253] Preparation of Compound II-1 (Example 1)

[0254] Compound A-1 (1.68 mg), diselenesium ether catalyst (0.5 mg), acetonitrile (2.5 mL), methylamine aqueous solution (40 wt%, 2 mL), and triethylamine (1.2 mg) were added sequentially to the reaction vessel. The vessel was then evacuated and rapidly purged three times with argon gas to ensure it was filled with argon. Under argon gas conditions, compounds B-1 (molar amount equal to compound A-1) and C-1 (molar amount equal to compound A-1) were added sequentially. The vessel was sealed and the mixture was stirred in a 60°C water bath for 72 hours. After the reaction was complete, saturated NaCl solution (0.5 mL) was added and mixed. The mixture was then diluted with ethyl acetate (10.0 mL). The diluted solution was dried over anhydrous Na₂SO₄, filtered, and concentrated by rotary evaporation. The concentrate was purified by column chromatography using n-hexane-ethyl acetate (2:1 v / v) as the eluent to obtain compound II-1.

[0255] Preparation of Compounds II-2 to II-6 in Examples 2-6

[0256] Prepare according to the steps and parameters in Preparation Example 1, but replace the raw materials accordingly.

[0257] Preparation of Compound II-7 (Example 7)

[0258] Compound A-1 (1.68 mg), diselenesium ether catalyst (0.5 mg), acetonitrile (2.5 mL), methylamine aqueous solution (40 wt%, 2 mL), and triethylamine (1.2 mg) were added sequentially to the reaction vessel. The vessel was evacuated and purged three times with argon gas to ensure it was filled with argon. Under argon gas conditions, the compound (molar amount equal to compound A-1) was added, and the mixture was sealed and stirred in a 60°C water bath for 72 hours. After the reaction was complete, saturated NaCl solution (0.5 mL) was added and mixed. The mixture was then diluted with ethyl acetate (10.0 mL). The diluted solution was dried over anhydrous Na₂SO₄, filtered, and concentrated by rotary evaporation. The concentrate was purified by column chromatography using n-hexane-ethyl acetate (2:1 v / v) as the eluent to obtain compound II-7.

[0259] Preparation Examples 8-9: Preparation of Compounds II-8 to II-9

[0260] Prepare the raw materials by following the steps and parameters in Preparation Example 7, but replacing them accordingly.

[0261] Example 1

[0262] (1) Preparation of electrolyte: Lithium bis(fluorosulfonyl)imide (LiFSI) was dissolved in dimethyl ethylene glycol (DME), and then compound II-1 was added to obtain the electrolyte. In the electrolyte, the molar concentration of lithium bis(fluorosulfonyl)imide was 4M, and the mass content of compound II-1 was 3%.

[0263] (2) Preparation of the positive electrode sheet: The positive electrode active material lithium nickel cobalt manganese oxide (NMC), the conductive agent acetylene black, and the binder PVDF were mixed at a mass ratio of 98:1:1. NMP solvent was added and stirred until the system was homogeneous to obtain the positive electrode slurry. The positive electrode slurry was uniformly coated on both sides of the positive electrode current collector aluminum foil, dried at room temperature, and then transferred to an oven for further drying. It was then cut into positive electrode sheets with an areal capacity of 3.5 mAh / cm². 2 .

[0264] (3) Preparation of negative electrode sheet: A 50μm thick lithium foil is rolled onto one side of a 12μm thick copper foil and then cut into negative electrode sheets for later use.

[0265] (4) Separation membrane: Polyethylene porous membrane is used.

[0266] (5) Battery cell assembly: The above-mentioned positive electrode, separator, and negative electrode are stacked in sequence to obtain an electrode assembly; the electrode assembly is placed in an outer packaging, the electrolyte prepared above is added, and after encapsulation, standing, formation, aging and other processes, a battery cell is obtained. Among them, the formation process is as follows: the battery cell is discharged at 1C to 1.7V, stood for 5 minutes, and then discharged at 0.5C to 1.7V; the above process is repeated 5 times.

[0267] The parameters that differentiate Examples 2-15 and Comparative Examples 1-3 from Example 1 are shown in Table 1.

[0268] Parameter testing

[0269] Element or compound testing in the positive electrode film: Disassemble the battery cell, remove the positive electrode sheet, clean it with a solvent (e.g., DMC), and dry it. Use XPS to perform a full-spectrum scan of the positive electrode film to obtain the spectrum. Compare the spectrum with a standard spectrum to determine the elements present. Analyze the chemical state and valence of the elements based on the spectrum to determine the compounds present.

[0270] Characteristic element layer thickness testing of the positive electrode film: The battery cell was disassembled, the positive electrode sheet was removed, and cleaned and dried with a solvent (e.g., DMC). XPS depth profiling mode was used, combined with an ion gun to peel off the sample surface layer by layer. Operating conditions: full spectrum mode; etching count set to 10; tuning value of 5keV Ar+; raster size of 3mm. The characteristic element layer thickness was obtained by measuring the depth data of the characteristic peaks of N or S elements in the sample.

[0271] The ambient temperature was set to 60℃. The battery was charged at a constant current of 0.2C (28mA) to the cutoff voltage of 4.3V, and then charged at a constant voltage of 4.3V until the current decayed to 0.1C (14mAh). Then, it was discharged at 1C (140mA) to 2.8V. This charge-discharge cycle was performed according to the above process. After 60 and 200 cycles, the positive electrode was removed, cleaned with a solvent (e.g., DMC), and dried. The surface of the positive electrode was tested using SEM, and the results are shown in Figures 7 and 8. Figure 7 shows the SEM image of the positive electrode of the battery cell in Example 1 after 200 cycles. Figure 8 shows the SEM image of the positive electrode of the battery cell in Comparative Example 1 after 60 cycles. The comparison shows that the CEI film on the surface of the positive electrode of the battery cell in Example 1 remained relatively intact and continuous after 200 cycles, while the CEI film on the surface of the positive electrode of the battery cell in Comparative Example 1 was severely cracked after 60 cycles.

[0272] Battery cell testing

[0273] (1) Normalized gas production test method of battery cell: The volume V1 of the battery cell before cycling is measured by water displacement method.

[0274] The ambient temperature was set to 60℃. The battery was charged at a constant current of 0.2C (28mA) to the cutoff voltage of 4.3V, and then charged at a constant voltage of 4.3V until the current decreased to 0.1C (14mAh). Then, it was discharged at 1C (140mA) to 2.8V. This charge-discharge cycle was repeated. When the discharge capacity decreased to 80% of the first cycle's discharge capacity, the battery cell was considered to have reached the end of its lifespan. The volume V2 of the battery cell after the end of its lifespan was measured using the water displacement method. The difference between V2 and V1 is the gas production volume V. Dividing the gas production volume V by the total charge capacity of the battery cell yields the normalized gas production; where the total charge capacity of the battery cell is equal to the sum of the charge capacities per cycle.

[0275] (2) High-temperature cycle life test method for individual battery cells: Set the ambient temperature to 60℃, charge the individual battery cells at 0.2C (i.e., 28mA), and after reaching the cutoff voltage of 4.3V, continue charging at a constant voltage of 4.3V until the current decays to 0.1C (i.e., 14mAh), and then discharge at 1C (i.e., 140mA) to 2.8V. Perform charge and discharge cycles according to the above process. When the discharge capacity decays to 80% of the discharge capacity of the first cycle, the life of the individual battery cell is considered to have ended, and the number of cycles at this time is recorded.

[0276] The results are shown in Table 2.

[0277] Table 2 Test results of Examples 1-15 and Comparative Examples 1-3

[0278] It can be seen from the above table:

[0279] Compared with Comparative Example 1 without the addition of compounds, the normalized gas production of the battery cells in Examples 1-15 of this application is significantly reduced and the high-temperature cycle life is significantly extended.

[0280] Adding compound to Comparative Example 2 In comparison, the normalized gas production of the battery cells in Examples 1-15 of this application is significantly reduced and the high-temperature cycle life is significantly extended.

[0281] Compared with Comparative Example 3, compound was added In comparison, the normalized gas production of the battery cells in Examples 1-15 of this application is significantly reduced and the high-temperature cycle life is significantly extended.

[0282] Compared with the lower amount of compound added in Example 11, the normalized gas production of the battery cells in Examples 1 and 10 of this application is significantly reduced and the high-temperature cycle life is significantly extended.

[0283] Compared with the higher amount of compound added in Example 12, the high-temperature cycle life of the battery cells in Examples 1 and 10 of this application is significantly extended.

[0284] Compared with the conventional formation process used in the battery cell of Example 14, the high-temperature cycle life of the battery cells of Examples 1 and 13 of this application is significantly extended.

[0285] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A battery cell, comprising an electrolyte, a positive electrode, and a negative electrode, wherein the positive electrode comprises a positive current collector and a positive electrode film layer located on at least one side of the positive current collector, and the electrolyte comprises a compound represented by Formula I. in, A is selected from elements N and S; R1 is independently selected from C 1-6 Alkyl, C 2-6 alkenyl, C 2-6 alkynyl group; R2 does not exist or R2 is selected from C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2-6 alkynyl, halogenated C 2-6 alkynyl group; R3 is selected from C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2- 6-Alkyne, Halogenated C 2-6 Alkyne group.

2. The battery cell according to claim 1, characterized in that... Any one of the following: R1 is independently selected from C 2-6 alkenyl, C 2-6 alkynyl group; R1 is independently selected from C 2-6 alkenyl; R1 is independently selected from C 2-4 alkenyl; R1 is independently selected from vinyl, allyl, and 1-propenyl.

3. The battery cell according to claim 1 or 2, characterized in that... Any one of the following: R2 is absent or R2 is selected from halogenated C. 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 alkynyl group; R2 is absent or R2 is selected from halogenated C. 1-6 alkyl; R2 is absent or R2 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms; R2 is absent or R2 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl; R2 is absent or R2 is selected from 3-fluoropropyl, 3,3-difluoropropyl, or 3,3,3-trifluoropropyl.

4. The battery cell according to any one of claims 1 to 3, characterized in that... Any one of the following: R3 is selected from halogenated C 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 alkynyl group; R3 is selected from halogenated C 1-6 alkyl; R3 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms; R3 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl; R3 is selected from 3-fluoropropyl, 3,3-difluoropropyl, and 3,3,3-trifluoropropyl.

5. The battery cell according to any one of claims 1 to 4, wherein, The compound is selected from:

6. The battery cell according to any one of claims 1 to 5, wherein, The positive electrode film layer includes one or more of the following: halogen, P element, N element, S element, Li3N, Li3P, lithium halide, and lithium sulfide.

7. The battery cell according to any one of claims 1 to 6, wherein, The positive electrode film layer includes a characteristic element layer, which is located on the side of the positive electrode film layer away from the positive electrode current collector, and the characteristic element layer includes N element or S element.

8. The battery cell according to claim 7, wherein, The thickness of the feature element layer is 1nm-10nm or 3nm-7nm.

9. The battery cell according to any one of claims 1 to 8, wherein, The compound is present in the electrolyte at a mass content of 1%-8% or 3%-5%.

10. The battery cell according to any one of claims 1 to 9, wherein, The battery cell is formed using one or more of the following operations: discharging the battery cell at 1C-3C to 1V-2V, allowing it to stand for 1min-20min, and then discharging it at 0.1C-1C to 1V-2V; and / or, The battery cell is formed by one or more of the following operations: discharging the battery cell at 1C-2C to 1.5V-1.9V, letting it stand for 5min-10min, and then discharging it at 0.2C-0.7C to 1.5V-1.9V.

11. The battery cell according to any one of claims 1 to 10, wherein, The positive electrode film layer includes a positive electrode active material, which includes one or more of lithium nickel cobalt manganese oxide, lithium iron phosphate, and lithium manganese iron phosphate.

12. The battery cell according to any one of claims 1 to 11, wherein, The battery cell includes one or more of lithium metal battery cells and lithium-ion battery cells.

13. The electrolyte additive shown in Formula I, in, A is selected from elements N and S; R1 is independently selected from C 1-6 Alkyl, C 2-6 alkenyl, C 2-6 alkynyl group; R2 does not exist or R2 is selected from C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2-6 alkynyl, halogenated C 2-6 alkynyl group; R3 is selected from C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 2-6 alkenyl, halogenated C 2-6 alkenyl, C 2- 6-Alkyne, Halogenated C 2-6 Alkyne group.

14. The electrolyte additive according to claim 13, characterized in that... Any one of the following: R1 is independently selected from C 2-6 alkenyl, C 2-6 alkynyl group; R1 is independently selected from C 2-6 alkenyl; R1 is independently selected from C 2-4 alkenyl; R1 is independently selected from vinyl, allyl, and 1-propenyl.

15. The electrolyte additive according to claim 13 or 14, characterized in that... Any one of the following: R2 is absent or R2 is selected from halogenated C. 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 alkynyl group; R2 is absent or R2 is selected from halogenated C. 1-6 alkyl; R2 is absent or R2 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms; R2 is absent or R2 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl; R2 is absent or R2 is selected from 3-fluoropropyl, 3,3-difluoropropyl, or 3,3,3-trifluoropropyl.

16. The electrolyte additive according to any one of claims 13 to 15, characterized in that... Any one of the following: R3 is selected from halogenated C 1-6 Alkyl, Halogenated C 2-6 alkenyl, halogenated C 2-6 alkynyl group; R3 is selected from halogenated C 1-6 alkyl; R3 is selected from C atoms substituted with one or more halogen atoms. 1-6 Alkyl group, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine, and iodine atoms; R3 is selected from C atoms substituted with one or more fluorine atoms. 1-6 alkyl; R3 is selected from 3-fluoropropyl, 3,3-difluoropropyl, and 3,3,3-trifluoropropyl.

17. The electrolyte additive according to any one of claims 13 to 16, wherein the electrolyte is selected from:

18. A method for preparing an electrolyte additive, which is either method one or method two; Method 1 includes the following steps: The compound shown in Formula A, the compound shown in Formula B, and the compound shown in Formula C are reacted in a solvent to obtain the compound shown in Formula I-1; The second method includes the following steps: The compound shown in Formula A is reacted with the compound shown in Formula D in a solvent to obtain the compound shown in Formula I-2; in, The definitions of R1, R2, and R3 are as described in any one of claims 1 to 17; X is selected from halogens.

19. A battery device comprising a battery cell according to any one of claims 1 to 12, an electrolyte additive according to any one of claims 13 to 17, or an electrolyte additive prepared by the method of claim 18.

20. An electrical device comprising a battery cell as described in any one of claims 1 to 12 or a battery device as described in claim 19.

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