Non-aqueous electrolyte, secondary batteries and power consumption devices

Abstract

This application relates to the battery technology, specifically to a non-aqueous electrolyte, a secondary battery, and a power consumption device. The non-aqueous electrolyte comprises a cyclic sulfate ester additive and a phosphate ester-based or isocyanate-based additive. This application also relates to a secondary battery comprising the non-aqueous electrolyte, and a power consumption device comprising the secondary battery. A second aspect of this application provides a secondary battery comprising any non-aqueous electrolyte described in the first aspect of this application, further comprising a positive electrode sheet and a negative electrode sheet, wherein the negative electrode sheet comprises a negative electrode material layer containing a negative electrode active material.

Description

[Technical Field]

[0001] This application relates to the battery technology field, and more particularly to non-aqueous electrolytes, secondary batteries, and power consumption devices. [Background technology]

[0002] As environmental problems become increasingly severe, the global pursuit of "carbon neutrality" is driving industries in a greener and healthier direction. Lithium-ion batteries, as a cleaner energy storage device, are beginning to be widely used in energy storage power systems such as hydroelectric, thermal, wind, and solar power plants, as well as in many fields such as electric vehicles, military equipment, and aerospace. Against this backdrop, China has introduced various policies to actively support the development of new energy-related industries since the "12th Five-Year Plan" period. With the rapid development of the industry, China's new energy sector has demonstrated its accumulated strength and achieved remarkable results, with many companies at the forefront of the new energy battery industry. At the same time, market competition has intensified, and consumers and investors are making higher demands on battery cycle performance and safety performance. [Overview of the Initiative]

[0003] In the field of automotive lithium-ion batteries, much attention is focused on battery range and cycle life. To achieve better range, researchers have attempted to increase the energy density of batteries by using positive and negative electrodes with higher compaction densities at the battery cell level. However, this also presents problems such as a significant decrease in sheet porosity at higher compaction densities, making it difficult for the electrolyte to penetrate the sheet, increasing sheet polarization, and easily raising impedance. Furthermore, the positive and negative electrode particles may be destroyed after high-pressure pressing, potentially causing problems such as the leaching of transition metals and violent reactions at the negative electrode interface. These problems significantly reduce the battery's cycle life.

[0004] To solve the above problems, this application provides a non-aqueous electrolyte and introduces cyclic sulfonic acid ester additives and phosphate ester or isocyanate additives to improve problems such as shortened battery life due to high compaction density of the positive and negative electrodes, thereby obtaining a lithium-ion secondary battery with high energy density and long lifespan.

[0005] A first aspect of this application provides a non-aqueous electrolyte comprising a first additive and a second additive, wherein the first additive is a cyclic sulfate ester compound having a structure represented by general formula (I), [ka] [ka] In general formula (I), R1, R2, R3, and R4 are each independently selected from one of the following: a group having the structure shown in general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group. In general formula (II), R5 and R6 are each independently selected from one of the following: a group having the structure shown in general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group. R1 and R2 cannot be hydrogen atoms at the same time, and R3 and R4 cannot be hydrogen atoms at the same time. The second additive is selected from phosphate ester compounds, isocyanate compounds, or combinations thereof. The phosphate ester compound has a structure represented by general formula (III), [ka] In general formula (III), R1, R2, R3, R4, and R5 are each independently selected from one of the following: a group having the structure shown in general formula (IV), a hydrogen atom, a C1-C6 alkyl group, a halogen atom, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C6-C10 aryl group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, a hydroxyl group, a sulfonic acid group, or a tri(C1-C6 alkyl)silyl group. In general formula (IV), R6, R7, and R8 are each independently selected from one of the following: a hydrogen atom, a C1-C6 alkyl group, a halogen atom, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C6-C10 aryl group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, or a sulfonic acid group. The isocyanate compound has a structure represented by general formula (V), [ka] In general formula (V), R1 is either unsubstituted or one or more R a Selected from C2-C10 alkylene groups, C2-C10 heteroalkylene groups, C6-C18 arylene groups, C2-C18 heteroarylene groups, C3-C18 divalent alicyclic groups, and C3-C18 heterodivalent alicyclic groups, The one or more R a Each of these is independently selected from halogen atoms, -CN, -NCO, -OH, -COOH, -SOOH, C2-C10 ester groups, C1-C10 alkyl groups, C2-C10 alkenyl groups, C2-C10 alkynyl groups, and C2-C10 alkoxy groups. In general formula (V), n is 1, 2, or 3.

[0006] In some embodiments, the cyclic sulfate ester compound is R 1 , R 2 , R 3 and R 4is independently selected from any one of a group having a structure represented by the general formula (II), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, and a sulfonic acid group. In the cyclic sulfate compound, R 5 and R 6 are independently selected from any one of a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, and a sulfonic acid group.

[0007] In some embodiments, in the cyclic sulfate compound, R 1 , R 2 , R 3 and R 4 are independently selected from any one of a group having a structure represented by the general formula (II), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, and a cyano group.

[0008] In some embodiments, in the cyclic sulfate compound, R 5 and R 6 are independently selected from any one of a hydrogen atom and a C1-C3 alkyl group.

[0009] In some embodiments, in the cyclic sulfate compound, R 1 , R 2 , R 3 and R 4 are independently selected from any one of a group having a structure represented by the general formula (II), a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyano group.

[0010] In some embodiments, in the cyclic sulfate compound, R 5 and R 6Each of these is independently selected from one of the following: a hydrogen atom, a methyl group, an ethyl group, a propyl group, and an isopropyl group.

[0011] In some embodiments, the base of the structure represented by the general formula (II) is [ka] One of the following groups is selected, where X is a F atom, a Cl atom, or a Br atom.

[0012] In some embodiments, the base of the structure represented by the general formula (II) is [ka] It is selected from one of the following bases.

[0013] In some embodiments, the cyclic sulfate ester compound is [ka] One or more of the following compounds are selected.

[0014] In some embodiments, the mass content of the cyclic sulfate ester compound in the non-aqueous electrolyte is W1, where 0.005% ≤ W1 ≤ 10%, and selectively 0.05% ≤ W1 ≤ 5%.

[0015] In some embodiments, in the phosphate ester compound, R1, R2, R3, R4, and R5 are each independently selected from one of the following: a group having the structure represented by general formula (IV), a hydrogen atom, a C1-C3 alkyl group, a halogen atom, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C6-C10 aryl group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, a hydroxyl group, a sulfonic acid group, and a tri(C1-C3 alkyl)silyl group. In general formula (IV), R6, R7, and R8 are each independently selected from one of the following: a hydrogen atom, a C1-C3 alkyl group, a halogen atom, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C6-C10 aryl group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, and a sulfonic acid group.

[0016] In some embodiments, in the phosphate ester compound, R1, R2, R3, R4, and R5 are each independently selected from one of the following: a group having the structure represented by general formula (IV), a hydrogen atom, a C1-C3 alkyl group, a halogen atom, a C1-C3 alkoxy group, or a tri(C1-C3 alkyl)silyl group.

[0017] In some embodiments, in general formula (IV), R6, R7, and R8 are each independently selected from one of a hydrogen atom, a C1-C3 alkyl group, or a C1-C3 alkoxy group.

[0018] In some embodiments, the base of the structure represented by general formula (IV) is [ka] It is selected from one of the following bases.

[0019] In some embodiments, the phosphate ester compound is [ka] One or more of the following compounds are selected.

[0020] In some embodiments, in the isocyanate compound, R1 is unsubstituted or one or more R a The group is selected from C2-C6 alkylene groups, C2-C6 heteroalkylene groups, C6-C10 arylene groups, C2-C10 heteroarylene groups, C4-C6 divalent alicyclic groups, and C4-C6 heterodivalent alicyclic groups.

[0021] In some embodiments, the one or more R a Each of these is independently selected from halogen atoms, -CN, -NCO, -OH, -COOH, -SOOH, C2-C6 ester groups, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and C2-C6 alkoxy groups.

[0022] In some embodiments, the one or more R a Each of these is independently selected from halogen atoms, -CN, -NCO, -OH, -COOH, -SOOH, C2-C3 ester groups, C1-C3 alkyl groups, C2-C3 alkenyl groups, C2-C3 alkynyl groups, and C2-C3 alkoxy groups.

[0023] In some embodiments, in the isocyanate compound, R1 is unsubstituted or one or more R a Selected from C2-C6 alkylene groups, C6-C10 arylene groups, and C4-C6 divalent alicyclic groups substituted with, and one or more of the above R a Each of these is independently selected from a halogen atom and a C1-C3 alkyl group.

[0024] In some embodiments, the isocyanate compound is [ka] One or more of the following compounds are selected.

[0025] In some embodiments, the mass percentage of the second additive in the non-aqueous electrolyte is W2, where 0.01% ≤ W2 ≤ 10%, selectively 0.1% ≤ W2 ≤ 8%, and selectively 0.3% ≤ W2 ≤ 5%.

[0026] A second aspect of this application provides a secondary battery comprising any non-aqueous electrolyte described in the first aspect of this application, further comprising a positive electrode sheet and a negative electrode sheet, wherein the negative electrode sheet comprises a negative electrode material layer containing a negative electrode active material.

[0027] In some embodiments, the porosity of the negative electrode material layer is 30% to 45%, and selectively 37% to 42%.

[0028] In some embodiments, the average particle size Dv50 of the negative electrode active material is 3 to 25 μm, selectively 5 μm ≤ Dv50 ≤ 20 μm, and selectively 7 μm ≤ Dv50 ≤ 15 μm.

[0029] In some embodiments, the coating amount per unit area of ​​the negative electrode sheet is CW, and is 2 mg / cm². 2 ≤CW ≤ 13 mg / cm³ 2 , selectively 5 mg / cm³ 2 ≤CW ≤ 10 mg / cm³ 2 That is the case.

[0030] A third aspect of this application provides a power consumption device comprising a secondary battery, the secondary battery including any secondary battery described in the second aspect of this application.

[0031] The non-aqueous electrolyte described in this application can extend the cycle life and storage life of secondary batteries at high temperatures. [Brief explanation of the drawing]

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings necessary for the embodiments of this application are briefly described below. Clearly, the drawings described below represent only a few embodiments of this application, and those skilled in the art can obtain further drawings based on these drawings without requiring any creative effort.

[0033] [Figure 1] This is a schematic diagram of a secondary battery according to one embodiment of the present application. [Figure 2] Figure 1 is an exploded view of a secondary battery according to one embodiment of this application. [Figure 3] This is a schematic diagram of a battery module according to one embodiment of the present application. [Figure 4] This is a schematic diagram of a battery pack according to one embodiment of the present application. [Figure 5] Figure 4 is an exploded view of a battery pack according to one embodiment of this application. [Figure 6] This is a schematic diagram of a power consumption device using a secondary battery as a power source according to one embodiment of the present application.

[0034] In the drawings, each drawing is not drawn to the actual scale. [Explanation of symbols]

[0035] 1 Battery pack, 2 Upper casing, 3 Lower casing, 4 Battery module, 5 Rechargeable battery, 51 Case, 52 Electrode assembly, 53 Top cover assembly. [Modes for carrying out the invention]

[0036] Embodiments of this application will be described in more detail below with reference to the drawings and examples. The detailed description of the following embodiments and drawings are used to illustrate the principles of this application, but are not intended to limit the scope of this application, that is, this application is not limited to the embodiments described.

[0037] The embodiments of the non-aqueous electrolyte, secondary battery, and power consumption device of this application will be described in detail below, with reference to the drawings as appropriate. However, unnecessarily detailed explanations may be omitted. For example, detailed explanations of well-known matters and redundant explanations of structures that are actually the same may be omitted. This is to avoid making the following explanation unnecessarily long and to make it easily understandable to those skilled in the art. The drawings and the following explanation are provided to enable those skilled in the art to fully understand this application and are not intended to limit the topics described in the claims.

[0038] The “range” disclosed in this application is limited in the form of a lower limit and an upper limit, and a given range is limited by selecting one lower limit and one upper limit, which define the boundary of a particular range. The range thus limited may or may not include the endpoints, and any combination is possible, that is, any lower limit can be combined with any upper limit to form a range. For example, if the ranges 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges 60-110 and 80-120 can also be assumed. Furthermore, if 1 and 2 are listed as the minimum range values ​​and 3, 4, and 5 are listed as the maximum range values, then the ranges 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5 can all be assumed. In this application, unless otherwise specified, the numerical range “a-b” represents an abbreviated expression for any combination of real numbers a-b, where a and b are both real numbers. For example, the numerical range "0 to 5" indicates that all real numbers between "0 to 5" have already been listed in this specification, and "0 to 5" is simply an abbreviated representation of combinations of these numbers. Also, when a parameter is described as an integer ≥ 2, it is equivalent to disclosing that this parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0039] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical inventions.

[0040] Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical concepts.

[0041] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the fact that the method includes steps (a) and (b) means that the method may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, the fact that the method referred to above may further include step (c) means that step (c) may be added to the method in any order, for example the method may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), and so on.

[0042] Unless otherwise specified, the terms “includes” and “inclusive” as used in this application may be open-ended or closed-ended. For example, “includes” and “inclusive” may further include or include other components not listed, or may include or include only the components listed.

[0043] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, any one of the following conditions satisfies the "A or B" condition: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), or both A and B are true (or exist).

[0044] [Nonaqueous electrolyte]

[0045] A first aspect of this application provides a non-aqueous electrolyte comprising a first additive and a second additive, wherein the first additive is a cyclic sulfate ester compound having a structure represented by general formula (I), [ka] [ka] In general formula (I), R1, R2, R3, and R4 are each independently selected from one of the following: a group having the structure shown in general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group. In general formula (II), R5 and R6 are each independently selected from one of the following: a group having the structure shown in general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group. R1 and R2 cannot be hydrogen atoms at the same time, and R3 and R4 cannot be hydrogen atoms at the same time. The second additive is selected from phosphate ester compounds, isocyanate compounds, or combinations thereof. The phosphate ester compound has a structure represented by general formula (III), [ka] In general formula (III), R1, R2, R3, R4, and R5 are each independently selected from one of the following: a group having the structure shown in general formula (IV), a hydrogen atom, a C1-C6 alkyl group, a halogen atom, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C6-C10 aryl group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, a hydroxyl group, a sulfonic acid group, or a tri(C1-C6 alkyl)silyl group. In general formula (IV), R6, R7, and R8 are each independently selected from one of the following: a hydrogen atom, a C1-C6 alkyl group, a halogen atom, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C6-C10 aryl group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, or a sulfonic acid group. The isocyanate compound has a structure represented by general formula (V), [ka] In general formula (V), R1 is either unsubstituted or one or more R a Selected from C2-C10 alkylene groups, C2-C10 heteroalkylene groups, C6-C18 arylene groups, C2-C18 heteroarylene groups, C3-C18 divalent alicyclic groups, and C3-C18 heterodivalent alicyclic groups, The one or more R a Each of these is independently selected from halogen atoms, -CN, -NCO, -OH, -COOH, -SOOH, C2-C10 ester groups, C1-C10 alkyl groups, C2-C10 alkenyl groups, C2-C10 alkynyl groups, and C2-C10 alkoxy groups. In general formula (V), n is 1, 2, or 3.

[0046] In some embodiments, the cyclic sulfate ester compound is R 1 , R 2 , R 3 and R 4 Each of these is independently selected from one of the following: a group having the structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, and a sulfonic acid group, and in the cyclic sulfate ester compound, R 5 and R 6Each of these is independently selected from one of the following: a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, and a sulfonic acid group.

[0047] The non-aqueous electrolyte according to this application contains various additives. Here, the cyclic sulfate ester additive can be involved in the formation of a film at the negative electrode interface during the initial charging process, and this film mainly consists of a mixture of inorganic and organic components. The SEI formed with the cyclic sulfate ester additive has a denser structure, Li + Due to its superior conductivity, it has the characteristic of lowering the negative electrode interface impedance. Furthermore, this SEI film has strong protective capabilities for the negative electrode, which can improve the battery's cycle and storage capabilities at high temperatures. However, at high temperatures, LiPF6 is prone to decomposition, generating HF and causing the sustained degradation of the SEI. By introducing phosphate ester-based or isocyanate-based additives into the electrolyte, the acid content in the electrolyte can be reduced, extending the battery's cycle and storage life at high temperatures.

[0048] The cyclic sulfate ester rings used in this application are all five-membered rings, which allows for the formation of a denser SEI film.

[0049] In the above general formula (I), R 1 , R 2 , R 3 and R 4 The substituent may be an alkyl group or a substituent containing F or N, and by introducing substituents such as alkyl groups, an elastic SEI film with a longer organic chain can be formed on the negative electrode, which can respond to volume changes of the negative electrode during the cycle and prevent the destruction of the SEI film. By introducing substituents containing F and N, etc., which are involved in film formation on the negative electrode, an SEI film rich in more inorganic components such as LiF and Li3N can be formed, improving the mechanical strength of the SEI film, thereby improving the stability of the negative electrode SEI film and achieving the objective of further improving battery cycle performance.

[0050] The alkyl group mentioned above may be a linear alkyl group, a branched alkyl group, or a cycloalkyl group, and includes, but is not limited to, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a cyclopropanyl group, a cyclobutanyl group, etc. The alkyl group in the haloalkyl group mentioned above may be a linear alkyl group, a branched alkyl group, or a cycloalkyl group, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a cyclopropanyl group, a cyclobutanyl group, etc., but is not limited to these. The halogen atom may be a fluorine atom, a chlorine atom, or a bromine atom, and the halogen atom may be any one or more hydrogen atoms on the alkyl group. The alkoxy group may be substituted, and the above alkoxy group includes, but is not limited to, a cyclopropanyl group, an oxetanyl group, etc., and the halogen atom in the haloalkoxy group may be a fluorine atom, a chlorine atom, or a bromine atom, and the halogen atom may substitute for any one or more hydrogen atoms on the alkoxy group, and the alkenyl group includes, but is not limited to, -CH=CH2, -CH=CH2CH3, -CH2CH=CH2, -CH2CH=CH2CH3, etc., and the ester group includes, but is not limited to, a methyl formate ester group, an ethyl formate ester group, an ethyl acetate ester group, a methyl propionate ester group, an ethyl propionate ester group, a propyl propionate ester group, etc.

[0051] In some embodiments, the cyclic sulfate ester compound is R 1 , R 2 , R 3 and R 4 Each of these is independently selected from one of the following: a group having the structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, and a cyano group.

[0052] In some embodiments, the cyclic sulfate ester compound is R 5 and R 6 Each of these is independently selected from either a hydrogen atom or a C1-C3 alkyl group.

[0053] In some embodiments, the cyclic sulfate ester compound is R 1 , R 2 , R 3 and R 4 Each of these is independently selected from one of the following: a group having the structure represented by general formula (II), a hydrogen atom, a F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyano group.

[0054] In some embodiments, the cyclic sulfate ester compound is R 5 and R 6 Each of these is independently selected from one of the following: a hydrogen atom, a methyl group, an ethyl group, a propyl group, and an isopropyl group.

[0055] In some embodiments, the base of the structure represented by the general formula (II) is [ka] One of the following groups is selected, where X is a F atom, a Cl atom, or a Br atom.

[0056] In some embodiments, the base of the structure represented by the general formula (II) is [ka] [ka] It is selected from one of the following bases.

[0057] In some embodiments, the cyclic sulfate ester compound is [ka] One or more of the following compounds are selected.

[0058] The above method for producing cyclic sulfate ester compounds is simpler, more readily available and implementable industrially, and provides more stable improvements to the cycle and storage performance of secondary batteries.

[0059] In some embodiments, the cyclic sulfate ester compound is R 1 , R 2 , R 3 , R 4 , R 5 and R 6 R 1 and R 2 It is simultaneously a hydrogen atom, and R 3 and R 4 One of the members is a hydrogen atom, and the other is one of the following: a group having the structure represented by general formula (II), a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and the group having the structure represented by general formula (II), 5 and R 6 The condition is met that it is impossible for both to be hydrogen atoms at the same time.

[0060] In some embodiments, the cyclic sulfate ester compound is R 1 , R 2 , R 3 , R 4 , R 5 and R 6 R 3 and R 4 It is simultaneously a hydrogen atom, and R 1 and R 2 One of the members is a hydrogen atom, and the other is one of the following: a group having the structure represented by general formula (II), a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and the group having the structure represented by general formula (II), 5 and R 6 The condition is met that it is impossible for both to be hydrogen atoms at the same time.

[0061] In some embodiments, the cyclic sulfate ester compound is R 5 and R 6 Each of these is independently selected from groups other than the structural group represented by general formula (II).

[0062] In some embodiments, the mass content of the cyclic sulfate ester compound in the non-aqueous electrolyte is W1, where 0.005% ≤ W1 ≤ 10%, and selectively 0.05% ≤ W1 ≤ 5%. When the mass ratio of the cyclic sulfonic acid ester additive in the electrolyte is within the above preferred range, the battery cell has even better cycle and storage performance.

[0063] In some embodiments, W1 may be less than 0.001%, or between 0.001% and 0.005%, 0.005% and 0.01%, 0.01% and 0.05%, 0.05% and 0.1%, 0.1% and 0.2%, 0.2% and 0.3%, 0.3% and 0.5%, 0.5% and 1%, 1% and 2%, 2% and 3%, 3% and 4%, 4% and 5%, 5% and 8%, 8% and 10%, 10% and 15%, or greater than 15%.

[0064] A method for producing a cyclic sulfate ester compound having the structure represented by general formula (I) of this application is provided with reference to the following synthesis route: [ka] Here, the reaction temperature in step 1 is controlled to 30-60°C, and the reaction temperature in step 2 is controlled to 10-30°C. Step 2 is catalyzed by a catalyst such as ruthenium trichloride trihydrate, and the oxidizing agent may be sodium hypochlorite, ozone, or the like.

[0065] In some embodiments, in the phosphate ester compound, R1, R2, R3, R4, and R5 are each independently selected from one of the following: a group having the structure represented by general formula (IV), a hydrogen atom, a C1-C3 alkyl group, a halogen atom, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C6-C10 aryl group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, a hydroxyl group, a sulfonic acid group, and a tri(C1-C3 alkyl)silyl group. In general formula (IV), R6, R7, and R8 are each independently selected from one of the following: a hydrogen atom, a C1-C3 alkyl group, a halogen atom, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C6-C10 aryl group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, and a sulfonic acid group.

[0066] In some embodiments, in the phosphate ester compound, R1, R2, R3, R4, and R5 are each independently selected from one of the following: a group having the structure represented by general formula (IV), a hydrogen atom, a C1-C3 alkyl group, a halogen atom, a C1-C3 alkoxy group, or a tri(C1-C3 alkyl)silyl group.

[0067] In some embodiments, in general formula (IV), R6, R7, and R8 are each independently selected from one of a hydrogen atom, a C1-C3 alkyl group, or a C1-C3 alkoxy group.

[0068] In some embodiments, the base of the structure represented by general formula (IV) is [ka] It is selected from one of the following bases.

[0069] In some embodiments, the phosphate ester compound is [ka] One or more of the following compounds are selected.

[0070] In some embodiments, in the isocyanate compound, R1 is unsubstituted or one or more R a The group is selected from C2-C6 alkylene groups, C2-C6 heteroalkylene groups, C6-C10 arylene groups, C2-C10 heteroarylene groups, C4-C6 divalent alicyclic groups, and C4-C6 heterodivalent alicyclic groups.

[0071] In some embodiments, the one or more R a Each of these is independently selected from halogen atoms, -CN, -NCO, -OH, -COOH, -SOOH, C2-C6 ester groups, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and C2-C6 alkoxy groups.

[0072] In some embodiments, the one or more R a Each of these is independently selected from halogen atoms, -CN, -NCO, -OH, -COOH, -SOOH, C2-C3 ester groups, C1-C3 alkyl groups, C2-C3 alkenyl groups, C2-C3 alkynyl groups, and C2-C3 alkoxy groups.

[0073] In some embodiments, in the isocyanate compound, R1 is unsubstituted or one or more R a Selected from C2-C6 alkylene groups, C6-C10 arylene groups, and C4-C6 divalent alicyclic groups substituted with, and one or more of the above R a Each of these is independently selected from a halogen atom and a C1-C3 alkyl group.

[0074] In some embodiments, the isocyanate compound is [ka] One or more of the following compounds are selected.

[0075] The above-mentioned method for producing the phosphate ester compound or isocyanate compound is simpler, easier to implement and industrially adopted, and provides more stable improvements to the cycle and storage performance of secondary batteries.

[0076] In some embodiments, the mass percentage of the second additive in the non-aqueous electrolyte is W2, where 0.01% ≤ W2 ≤ 10%, selectively 0.1% ≤ W2 ≤ 8%, and selectively 0.3% ≤ W2 ≤ 5%. When the mass percentage of the second additive in the electrolyte is within the above preferred range, the battery cell has even better cycle and storage performance.

[0077] In some embodiments, W2 may be less than 0.001%, or between 0.001% and 0.005%, 0.005% and 0.01%, 0.01% and 0.05%, 0.05% and 0.1%, 0.1% and 0.2%, 0.2% and 0.3%, 0.3% and 0.5%, 0.5% and 1%, 1% and 2%, 2% and 3%, 3% and 4%, 4% and 5%, 5% and 6%, 6% and 8%, 8% and 9%, 9% and 10%, 10% and 12%, or greater than 12%.

[0078] In some embodiments, the non-aqueous electrolyte used in the present invention further comprises an electrolyte, and any electrolyte that is commonly used in non-aqueous electrolytes can be used in the non-aqueous electrolyte of this application. Those skilled in the art can select the non-aqueous electrolyte depending on the battery system used, for example, by selecting a conventional electrolyte suitable for secondary batteries. In some embodiments, the electrolyte comprises an alkali metal salt-based electrolyte, and the electrolyte comprises a lithium salt, selectively comprising one or more lithium salts selected from the group consisting of lithium hexafluoride phosphate, lithium perchlorate, lithium hexafluoride arsenate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethanesulfonyl)imide. Each of the above lithium salts may be used alone or in combination of two or more.

[0079] The electrolyte content in the non-aqueous electrolyte can refer to the electrolyte content in conventional non-aqueous electrolytes, and in some embodiments, the electrolyte content in the non-aqueous electrolyte is 0.1 mol / L to 5 mol / L, for example, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 4 mol / L, or 5 mol / L. In some embodiments, the non-aqueous electrolyte further comprises a non-aqueous solvent, which selectively comprises one or more selected from the group consisting of cyclic carbonates, linear carbonates, nitrile solvents, ketone solvents and sulfone solvents, and further selectively comprises one or more selected from the group consisting of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene 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, ethyl methyl sulfone, diethyl sulfone, tetrahydrofuran, ethylene glycol dimethyl ether, dioxolane, acetone, acetonitrile and butyronitrile. The above non-aqueous solvents may be used alone or in combination of two or more. For example, a mixed solvent of cyclic carbonate esters and linear carbonate esters may be used to improve the load characteristics and low-temperature characteristics of secondary batteries. In some embodiments, EC+EMC (ethylene carbonate + ethyl methyl carbonate) is used as the non-aqueous solvent.

[0080] When applying the non-aqueous electrolyte of this application to a solid battery, a solid solvent such as dimethyl sulfone may be used.

[0081] In addition to the additives described above, the additives may further include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve some of the battery's performance characteristics, such as additives that improve the battery's overcharge performance and additives that improve the battery's high-temperature or low-temperature performance. In some embodiments, the additives may further include, but are not limited to, one or more selected from the group consisting of sulfate ester compounds, sulfite ester compounds, sultone compounds, disulfonic acid compounds, nitrile compounds, aromatic compounds, isocyanate compounds, phosphazene compounds, cyclic acid anhydride compounds, phosphite ester compounds, phosphate ester compounds, borate ester compounds, and carboxylic acid ester compounds.

[0082] [Secondary battery]

[0083] A second aspect of this application provides a secondary battery. A secondary battery, also called a rechargeable battery or storage battery, refers to a battery that can be used continuously by activating the active material through charging after the battery has been discharged. Generally, a secondary battery includes a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte. During the charging and discharging process of the battery, active ions (e.g., lithium ions) reciprocate between the positive electrode sheet and the negative electrode sheet, undergoing intercalation and deintercalation. The separator is placed between the positive electrode sheet and the negative electrode sheet and mainly serves to prevent short circuits between the positive and negative electrodes, while also allowing active ions to pass through. The electrolyte mainly serves to conduct active ions between the positive electrode sheet and the negative electrode sheet.

[0084] [Negative electrode sheet]

[0085] The secondary battery according to this application may include a negative electrode sheet, the negative electrode sheet includes a negative electrode material layer, and the negative electrode material layer includes a negative electrode active material.

[0086] The porosity of the negative electrode material layer represents the amount of voids between particles within the sheet. In some embodiments, the porosity of the negative electrode material layer is 30% to 45%, and selectively 37% to 42%. When the porosity of the negative electrode material layer is within the above range, the number of voids between particles within the sheet is appropriate, the particle structure is less susceptible to damage by compression, electrolyte penetration is better, the long-term cycle performance of the battery cell is good, and at the same time, the energy density of the battery cell is not affected.

[0087] In some embodiments, the porosity of the negative electrode material layer is less than 25%, or 25% to 30%, 30% to 35%, 35% to 37%, 37% to 39%, 39% to 40%, 40% to 42%, 42% to 44%, 44% to 45%, 45% to 48%, or greater than 48%.

[0088] Porosity P of the negative electrode sheet n This can be obtained by a gas filling method, for example, by filling the voids of the negative electrode sheet with He gas, measuring the true volume V2 of the negative electrode sheet, and then calculating the apparent volume V1 of the negative electrode sheet from the coating amount and the compaction density of the negative electrode sheet, and the porosity P of the negative electrode sheet. n = (V1 - V2) / V1 × 100%.

[0089] The particle size of the negative electrode active material can be expressed as Dv50, where Dv50 refers to the particle size corresponding to the point when the cumulative volume percentage reaches 50%, i.e., the median diameter of the volume distribution. In some embodiments, the average particle size Dv50 of the negative electrode active material used in the present invention is 3 to 25 μm, and arbitrarily 5 μm ≤ Dv50 ≤ 20 μm and arbitrarily 7 μm ≤ Dv50 ≤ 15 μm. When the Dv50 of the negative electrode active material is within the above preferred range, it is advantageous for forming a uniform surface when manufacturing the coated sheet, and also advantageous for reducing side reactions between the electrode and the electrolyte, reducing the loss of initial battery capacity, and improving battery performance.

[0090] In some embodiments, Dv50 may be less than 0.5 μm, or 0.5 μm to 1 μm, 1 μm to 1.5 μm, 1.5 μm to 2 μm, 2 μm to 3 μm, 3 μm to 5 μm, 5 μm to 7 μm, 7 μm to 10 μm, 10 μm to 15 μm, 15 μm to 18 μm, 18 μm to 20 μm, 20 μm to 22 μm, 22 μm to 25 μm, 25 μm to 30 μm, or greater than 30 μm.

[0091] Dv50 can be measured using instruments and methods known in the art. For example, it was tested using a laser diffraction particle size distribution measuring device (Malvern Mastersizer 3000) manufactured by Malvern Instruments, UK. The particle size distribution was measured in accordance with the laser diffraction method for particle size distribution GB / T19077 - 2016 to obtain Dv50.

[0092] The negative electrode sheet can be manufactured by applying a negative electrode slurry to the surface of the negative electrode current collector. The coating amount per unit area of the electrode sheet refers to the dry weight of the slurry coated on the surface of the current collector per unit area. In some embodiments, the coating amount per unit area of the negative electrode sheet is CW, and 2 mg / cm 2 ≦CW≦13 mg / cm 2 , optionally 5 mg / cm 2 ≦CW≦10 mg / cm 2 . When the coating amount per unit area of the negative electrode sheet is within the above range, the battery has good kinetic performance and does not affect the energy density of the battery.

[0093] In some embodiments, CW is less than 1.5 mg / cm 2 , or 1.5 mg / cm 2 ~2 mg / cm 2 , 2 mg / cm 2 ~3 mg / cm 2 , 3 mg / cm 2 ~5 mg / cm 2 , 5 mg / cm 2 ~6 mg / cm 2 , 6 mg / cm 2 ~8 mg / cm 2 , 8 mg / cm 2~10 mg / cm³ 2 , 10 mg / cm³ 2 ~12 mg / cm³ 2 , 12 mg / cm³ 2 ~13 mg / cm³ 2 , 13 mg / cm³ 2 ~15 mg / cm³ 2 , or 15 mg / cm³ 2 It's perfectly fine.

[0094] The amount of coating per unit area of ​​the electrode sheet can be measured by the following method: Take several current collector foils of area S, weigh each one, take the average value and label it M1; take several sheets coated with the same weight of slurry, coat them uniformly, dry them at 120°C for 1 hour, and after detecting that they are substantially free of solvent, weigh each dried current collector foil with slurry coated on one side, take the average value and label it M2; and the coating weight of the active material layer on one side of the current collector CW = (M2 - M1) / S.

[0095] The negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer placed on at least one surface of the negative electrode current collector. For example, the negative electrode current collector has two opposing surfaces in its thickness direction, and the negative electrode material layer is placed on one or both of the two opposing surfaces of the negative electrode current collector.

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

[0097] In some embodiments, the negative electrode active material may be any negative electrode active material known in the art for batteries. For example, the negative electrode active material may include at least one material from among graphite (e.g., artificial graphite, natural graphite), soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy. The tin-based material may be selected from at least one of elemental tin, tin oxide, and tin alloy. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may be used. These negative electrode active materials may be used individually or in combination of two or more.

[0098] In some embodiments, the negative electrode material layer may further optionally contain an adhesive. For example, the adhesive 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).

[0099] In some embodiments, the negative electrode material layer further selectively comprises a conductive agent. For 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.

[0100] In some embodiments, the negative electrode material layer further selectively includes other additives, such as thickeners (e.g., sodium carboxymethylcellulose (CMC-Na)).

[0101] In some embodiments, a negative electrode sheet can be manufactured by the following method: components for manufacturing the negative electrode sheet, such as a negative electrode active material, a conductive agent, an adhesive, and any other components, are dispersed in a solvent (e.g., deionized water) to form a negative electrode slurry; the negative electrode slurry is applied to a negative electrode current collector; and after processes such as drying and cold pressing, a negative electrode sheet is obtained.

[0102] [Positive electrode sheet]

[0103] The secondary battery according to this application may include a positive electrode sheet, which typically includes a positive electrode current collector and a positive electrode material layer provided on at least one surface of the positive electrode current collector. For example, the positive electrode current collector has two opposing surfaces in its thickness direction, and the positive electrode material layer is provided on one or both of the two opposing surfaces of the positive electrode current collector.

[0104] In some embodiments, the positive electrode current collector may be a metal foil sheet or a composite current collector. For example, aluminum foil may be used as the metal foil sheet. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. 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) on a polymer material substrate (for example, a substrate such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0105] In some embodiments, the positive electrode material layer may include a positive electrode active material. Positive electrode active materials known in the art for batteries may be used. For example, the positive electrode active material may include at least one of olivine-structured lithium-containing phosphates, lithium transition metal oxides, 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 be used. These positive electrode active materials may be used individually or in combination of two or more. Here, examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 (It may also be abbreviated as LiNi) 0.5 Co 0.2 Mn 0.3 O2(NCM 523 (It may also be abbreviated as LiNi) 0.5 Co 0.25 Mn 0.25 O2(NCM 211 (It may also be abbreviated as LiNi) 0.6 Co 0.2 Mn 0.2 O2(NCM 622 (It may also be abbreviated as LiNi) 0.8 Co 0.1 Mn 0.1 O2(NCM 811 (May be abbreviated as LiNi) Lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05The lithium-containing phosphate with an olivine structure may include, but is not limited to, at least one of O2 and its modified compounds. For example, the lithium-containing phosphate may include, but is not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which may also be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, or a composite material of lithium iron manganese phosphate and carbon.

[0106] In some embodiments, the positive electrode material layer optionally further comprises an adhesive. For example, the adhesive 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 fluorine-containing acrylate resin.

[0107] In some embodiments, the cathode material layer further selectively comprises a conductive agent. For 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.

[0108] In some embodiments, a positive electrode sheet can be manufactured by the following method: Disperse the above components for manufacturing a positive electrode sheet, such as a positive electrode active material, a conductive agent, an adhesive, and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; apply the positive electrode slurry to a positive electrode current collector; and obtain a positive electrode sheet after going through processes such as drying and cold pressing.

[0109] [Separator]

[0110] In some embodiments, the secondary battery further includes a separator. This application is not particularly limited to the type of separator, and any known porous separator having good chemical and mechanical stability may be selected.

[0111] In some embodiments, the material of the separator may be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multilayer composite film, and is not particularly limited. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and is not particularly limited.

[0112] In some embodiments, the positive electrode plate, negative electrode plate, and separator can be manufactured as an electrode assembly by a winding process or a lamination process.

[0113] In some embodiments, the secondary battery may include an outer casing. This casing may be used to package the electrode assembly and electrolyte.

[0114] In some embodiments, the casing of the secondary battery may be a rigid case, such as a rigid plastic case, an aluminum case, or a steel case. The casing of the secondary battery may also be a pouch, such as a bag-shaped pouch. The material of the pouch may be plastic, and examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0115] This application does not particularly limit the shape of the secondary battery, which may be cylindrical, rectangular, or any other shape. For example, Figure 1 shows a rectangular secondary battery 5 as an example.

[0116] In some embodiments, referring to Figure 2, the casing may include a case 51 and a cover plate 53. Here, the case 51 may include a bottom plate and side plates connected to the bottom plate, the bottom plate and side plates enclosing and forming a housing cavity. The case 51 has an opening that communicates with the housing cavity, and the cover plate 53 can cover the opening and seal the housing cavity. The positive electrode plate, negative electrode plate and separator can form an electrode assembly 52 by a winding process or a lamination process. The electrode assembly 52 is packaged within the housing cavity. The electrolyte is impregnated into the electrode assembly 52. ​​The number of electrode assemblies 52 included in the secondary battery 5 may be one or more, and those skilled in the art can specifically select them according to actual needs.

[0117] In some embodiments, the secondary batteries may be assembled into a battery module, and the number of secondary batteries included in the battery module may be one or more, and the specific number can be selected by those skilled in the art depending on the application and capacity of the battery module.

[0118] Figure 3 shows an example of a battery module 4. Referring to Figure 3, in the battery module 4, multiple secondary batteries 5 may be installed in a sequential arrangement along the longitudinal direction of the battery module 4. Of course, they may be arranged in any other manner. Furthermore, these multiple secondary batteries 5 may be fixed in place with fasteners.

[0119] Selectively, the battery module 4 may further include a housing having a housing space, in which a plurality of secondary batteries 5 are housed.

[0120] In some embodiments, the battery modules may be further assembled into a battery pack, the number of battery modules included in the battery pack may be one or more, and the specific number can be selected by those skilled in the art depending on the application and capacity of the battery pack.

[0121] Figures 4 and 5 show an example of a battery pack 1. Referring to Figures 4 and 5, the battery pack 1 may include a battery box and a plurality of battery modules 4 installed in the battery box. The battery box includes an upper housing 2 and a lower housing 3, the upper housing 2 being covered by the lower housing 3 and forming a sealed space for housing the battery modules 4. The plurality of battery modules 4 may be arranged in the battery box in any manner.

[0122] The present application further provides a power consumption device comprising at least one of a secondary battery, battery module, or battery pack as described herein. The secondary battery, battery module, or battery pack may be used as a power source for the power consumption device or as an energy storage unit for the power consumption device. The power consumption 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.

[0123] The aforementioned power consumption device can be selected from a secondary battery, battery module, or battery pack depending on the usage demand.

[0124] Figure 6 shows an example of a power consumption device. This power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density needs of the secondary battery of this power consumption device, a battery pack or battery module can be used. [Examples]

[0125] [Examples]

[0126] Examples of the present application are described below. The examples described below are illustrative and are for interpretive purposes only, and should not be considered as limitations thereon. Where no specific technical or condition is specified in the examples, the technical or condition is as described in the literature in the art, or in accordance with product specifications. Where the manufacturer of the reagents or equipment used is not specified, they are all commercially available common products, and information on the remaining reagents or compounds is recorded in Table 1.

[0127] [Table 1-1] [Table 1-2] [Table 1-3]

[0128] Synthesis example

[0129] A method for producing a cyclic sulfate ester compound having the structure represented by general formula (I) of this application is provided with reference to the following synthesis route: [ka] Here, the reaction temperature in step 1 is controlled to 30-60°C, and the reaction temperature in step 2 is controlled to 10-30°C. Step 2 is catalyzed by a catalyst such as ruthenium trichloride trihydrate, and the oxidizing agent may be sodium hypochlorite, ozone, or the like.

[0130] Synthesis example 1: Compound 1 [ka] synthesis

[0131] Step 1: Add 300 g (2 mol) of solid 1,6-dideoxygalactitol to a 5 L three-necked flask and start stirring. Add 523 g (4.4 mol) of thionyl chloride dropwise to the three-necked flask, controlling the temperature to approximately 15°C during the addition process. After the addition is complete, keep warm at 45°C for 4 hours to allow the reaction to proceed. A large amount of slurry-like solid precipitates from the reaction solution. After cooling, slowly add 1 L of deionized water dropwise, quickly stir the reaction system to disperse, filter to obtain the solid, wash by beating several times with deionized water until the pH becomes neutral, and dry the filtered cake under reduced pressure at 60°C to obtain intermediate product 1.

[0132] Step 2: Add 184.2 g (0.8 mol) of intermediate product 1 to a 3 L three-necked flask, add 1000 mL of acetonitrile, add 80 mg of ruthenium trichloride trihydrate catalyst, purge the system with nitrogen gas, cool the system to 20°C, start stirring, and within 1 hour add 2000 g of 20% sodium hypochlorite aqueous solution dropwise to control the reaction temperature to 10-20°C. After the dropwise addition is complete, stir at 10-20°C for 10 minutes, perform liquid-liquid extraction, quench the organic phase with sodium sulfite aqueous solution, continue until the potassium starch iodide test paper no longer turns blue, repeat the liquid-liquid extraction, concentrate the organic layer, and crystallize it with acetonitrile to obtain a white powder solid, i.e., compound 1. 1H-NMR, CD3CN, δ ppm 5.42-5.39 (m, 2H), 5.36-5.34 (m, 2H), 1.67-1.65 (d, 6H).

[0133] Synthesis example 2: Compound 2 [ka] synthesis

[0134] Step 1: Add 356.5 g (2 mol) of solid 3,4,5,6-octanetetraol to a 5 L three-necked flask and start stirring. Add 523 g (4.4 mol) of thionyl chloride dropwise to the three-necked flask, controlling the temperature to approximately 15°C during the addition process. After the addition is complete, keep warm at 45°C for 4 hours to allow the reaction to proceed. A large amount of slurry-like solid precipitates from the reaction solution. After cooling, slowly add 1 L of deionized water dropwise, quickly stir the reaction system to disperse, filter to obtain the solid, wash by beating several times with deionized water until the pH becomes neutral, and dry the filtered cake under reduced pressure at 60°C to obtain intermediate product 2.

[0135] Step 2: Add 216.2 g (0.8 mol) of intermediate product 2 to a 3 L three-necked flask, add 1000 mL of acetonitrile, add 80 mg of ruthenium trichloride trihydrate catalyst, purge the system with nitrogen gas, cool the system to 20°C, start stirring, add 2000 g of 20% sodium hypochlorite aqueous solution dropwise within 1 hour, control the reaction temperature to 10-20°C, after the dropwise addition is complete, stir at 10-20°C for 10 minutes, perform liquid-liquid extraction, quench the organic phase with sodium sulfite aqueous solution, continue until the potassium starch iodide test paper no longer turns blue, repeat the liquid-liquid extraction, concentrate the organic layer, and crystallize it with acetonitrile to obtain compound 2.

[0136] Synthesis example 3: Compound 3 [ka] synthesis

[0137] Step 1: Add 328.4 g (2 mol) of solid 2,3,4,5-heptanetetraol to a 5 L three-necked flask and start stirring. Add 523 g (4.4 mol) of thionyl chloride dropwise to the three-necked flask, controlling the temperature to approximately 15°C during the addition process. After the addition is complete, keep warm at 45°C for 4 hours to allow the reaction to proceed. A large amount of slurry-like solid precipitates from the reaction solution. After cooling, slowly add 1 L of deionized water dropwise, quickly stir the reaction system to disperse, filter to obtain the solid, wash by beating several times with deionized water until the pH becomes neutral, and dry the filtered cake under reduced pressure at 60°C to obtain intermediate product 3.

[0138] Step 2: Add 205 g (0.8 mol) of intermediate product 3 to a 3 L three-necked flask, add 1000 mL of acetonitrile, and stir until the solid is completely dissolved. Add 80 mg of ruthenium trichloride trihydrate catalyst, purge the system with nitrogen gas, cool the system to 20°C, start stirring, and within 1 hour add 2000 g of 20% sodium hypochlorite aqueous solution dropwise to control the reaction temperature to 10-20°C. After the dropwise addition is complete, stir at 10-20°C for 10 minutes, perform liquid-liquid extraction, quench the organic phase with sodium sulfite aqueous solution, continue until the potassium starch iodide test paper no longer turns blue, repeat the liquid-liquid extraction, concentrate the organic layer, and crystallize it with acetonitrile to obtain compound 3 (163.1 g, yield 82.8%).

[0139] The synthesis methods for the following compounds were based on Synthesis Example 1, using the corresponding substrates in Table 2 instead of 1,6-dideoxygalactitol.

[0140] [Table 2]

[0141] Synthesis example 4: Compound 5 [ka] synthesis

[0142] Step 1: Add 392.4 g (2 mol) of solid 1,2,3,4,5,6-heptanehexaol to a 5 L three-necked flask and start stirring. Add 784.5 g (6.6 mol) of thionyl chloride dropwise to the three-necked flask, controlling the temperature to approximately 15°C during the addition process. After the addition is complete, keep warm at 45°C for 4 hours to allow the reaction to proceed. A large amount of slurry-like solid precipitates from the reaction solution. After cooling, slowly add 1 L of deionized water dropwise, quickly stir the reaction system to disperse, filter to obtain the solid, wash by beating several times with deionized water until the pH becomes neutral, and dry the filtered cake under reduced pressure at 60°C to obtain intermediate product 4.

[0143] Step 2: Add 140 g (0.4 mol) of intermediate product 4 to a 4 L three-necked flask, add 1000 mL of acetonitrile, add 110 mg of ruthenium trichloride trihydrate catalyst, purge the system with nitrogen gas, cool the system to 20°C, start stirring, add 1500 g of 20% sodium hypochlorite aqueous solution dropwise within 1 hour, control the reaction temperature to 10-20°C, after the dropwise addition is complete, stir at 10-20°C for 10 minutes, perform liquid-liquid extraction, quench the organic phase with sodium sulfite aqueous solution, continue until the potassium starch iodide test paper no longer turns blue, repeat the liquid-liquid extraction, concentrate the organic layer, and crystallize it with acetonitrile to obtain compound 5.

[0144] The synthesis methods for the following compounds were based on Synthesis Example 4, using the corresponding substrates in Table 3 instead of 1,2,3,4,5,6-heptanehexaol.

[0145] [Table 3]

[0146] Synthesis example 5: Compound 7 [ka] synthesis

[0147] Step 1: Add 484 g (2 mol) of solid octitol to a 5 L three-necked flask and start stirring. Add 1046 g (8.8 mol) of thionyl chloride dropwise to the three-necked flask, controlling the temperature to approximately 15°C during the addition process. After the addition is complete, keep the flask warm at 45°C for 4 hours to allow the reaction to proceed. A large amount of slurry-like solid precipitates from the reaction solution. After cooling, slowly add 1 L of deionized water dropwise, quickly stir the reaction system to disperse the solid, filter it, wash the resulting solid by beating it several times with deionized water until the pH becomes neutral, and dry the filtered cake under reduced pressure at 60°C to obtain intermediate product 5.

[0148] Step 2: Add 183.2 g (0.4 mol) of intermediate product 5 to a 4 L three-necked flask, add 1000 mL of acetonitrile, add 150 mg of ruthenium trichloride trihydrate catalyst, purge the system with nitrogen gas, cool the system to 20°C, start stirring, add 2000 g of 20% sodium hypochlorite aqueous solution dropwise within 1 hour, control the reaction temperature to 10-20°C, after the dropwise addition is complete, stir at 10-20°C for 10 minutes, perform liquid-liquid extraction, quench the organic phase with sodium sulfite aqueous solution, continue until the potassium starch iodide test paper no longer turns blue, repeat the liquid-liquid extraction, concentrate the organic layer, and crystallize it with acetonitrile to obtain compound 7.

[0149] Example 1

[0150] Electrolyte composition: Compound 1 was used as the first additive, with a mass content of 2% in the electrolyte, and Compound 12 was used as the second additive, with a mass content of 2% in the electrolyte. LiPF6 was used as the electrolyte, with a content of 10% in the electrolyte, and a mixture of EC+EMC (ethylene carbonate + ethyl methyl carbonate) in a volume ratio of 3:7 was used as the solvent.

[0151] Manufacturing of positive electrode sheets:

[0152] Lithium iron phosphate (LiFePO4) as the positive electrode active material, acetylene black as the conductive agent, and polyvinylidene fluoride (PVDF) as the adhesive were dissolved in the solvent N-methylpyrrolidone (NMP) in a mass ratio of 90:5:5. After thorough stirring and homogeneous mixing, a positive electrode slurry was obtained. Subsequently, the positive electrode slurry was uniformly applied to a positive electrode current collector, and after drying, cold pressing, and slitting, a positive electrode sheet was obtained.

[0153] Manufacturing of negative electrode sheets:

[0154] A negative electrode slurry was prepared by dissolving graphite (average particle size Dv50 is 10 μm) as the negative electrode active material, carbon black as the conductive agent, styrene-butadiene rubber (SBR) as the adhesive, and sodium carboxymethylcellulose (CMC-Na) as the thickener in a mass ratio of 90:4:4:2 in deionized water as the solvent and mixing them uniformly. The negative electrode slurry was then uniformly applied to the copper foil of the negative electrode current collector in one or more applications, followed by drying, cold pressing, and slitting to obtain a negative electrode sheet. The coating amount per unit area (CW) of the negative electrode sheet was 8 mg / cm². 2 That is the case.

[0155] Dv50 of the negative electrode active material refers to the particle size corresponding to when the cumulative volume percentage of the negative electrode active material reaches 50%, i.e., the median diameter of the volume distribution, and its unit is μm. Dv50 can be measured using instruments and methods known in this field. For example, it was tested using a laser diffraction particle size distribution analyzer (Malvern Mastersizer 3000) manufactured by Malvern Instruments Ltd., UK, and the particle size distribution was measured in accordance with the particle size distribution laser diffraction method GB / T19077-2016 to obtain Dv50.

[0156] The porosity of the negative electrode material layer in the negative electrode sheet is 39%.

[0157] Porosity P of the negative electrode sheet n This can be obtained by a gas filling method, for example, by filling the voids of the negative electrode sheet with He gas, measuring the true volume V2 of the negative electrode sheet, and then calculating the apparent volume V1 of the negative electrode sheet from the coating amount and the compaction density of the negative electrode sheet, and the porosity P of the negative electrode sheet. n = (V1 - V2) / V1 × 100%.

[0158] [Separator]

[0159] A conventional polypropylene film was used as the separator.

[0160] Lithium-ion battery assembly:

[0161] A positive electrode sheet, a separator, and a negative electrode sheet are stacked in order, with the separator placed between the positive and negative electrode sheets to act as an isolation element. The assembly is then wound up to obtain an electrode assembly, which is placed in a battery case. After drying, an electrolyte solution is injected, and after processes such as chemical formation and standing, a lithium-ion battery is obtained.

[0162] Example 2-1

[0163] The procedure was the same as in Example 1, except that compound 2 was used as the first additive instead of compound 1.

[0164] Example 2-2

[0165] The procedure was the same as in Example 1, except that compound 3 was used as the first additive instead of compound 1.

[0166] Examples 2-3

[0167] The procedure was the same as in Example 1, except that compound 4 was used as the first additive instead of compound 1.

[0168] Examples 2-4

[0169] The procedure was the same as in Example 1, except that compound 5 was used as the first additive instead of compound 1.

[0170] Examples 2-5

[0171] The procedure was the same as in Example 1, except that compound 6 was used as the first additive instead of compound 1.

[0172] Examples 2-6

[0173] The procedure was the same as in Example 1, except that compound 7 was used as the first additive instead of compound 1.

[0174] Example 3-1

[0175] It was carried out in the same manner as in Example 1, except that the mass content of the first additive compound 1 was adjusted to 0.001%.

[0176] Example 3-2

[0177] It was carried out in the same manner as in Example 1, except that the mass content of the first additive compound 1 was adjusted to 0.01%.

[0178] Example 3-3

[0179] It was carried out in the same manner as in Example 1, except that the mass content of the first additive compound 1 was adjusted to 4%.

[0180] Example 3-4

[0181] It was carried out in the same manner as in Example 1, except that the mass content of the first additive compound 1 was adjusted to 8%.

[0182] Example 3-5

[0183] It was carried out in the same manner as in Example 1, except that the mass content of the first additive compound 1 was adjusted to 15%.

[0184] Example 4-1

[0185] It was carried out in the same manner as in Example 1, except that compound 9 was used as the second additive instead of compound 12.

[0186] Example 4-2

[0187] It was carried out in the same manner as in Example 1, except that compound 10 was used as the second additive instead of compound 12.

[0188] Example 4-3

[0189] It was carried out in the same manner as in Example 1, except that compound 11 was used as the second additive instead of compound 12.

[0190] Example 4-4

[0191] The procedure was the same as in Example 1, except that compound 13 was used as the second additive instead of compound 12.

[0192] Examples 4-5

[0193] The procedure was the same as in Example 1, except that compound 14 was used as the second additive instead of compound 12.

[0194] Examples 4-6

[0195] The procedure was the same as in Example 1, except that compound 15 was used as the second additive instead of compound 12.

[0196] Examples 4-7

[0197] The procedure was the same as in Example 1, except that compound 16 was used as the second additive instead of compound 12.

[0198] Examples 4-8

[0199] The procedure was the same as in Example 1, except that compound 17 was used as the second additive instead of compound 12.

[0200] Examples 4-9

[0201] The procedure was the same as in Example 1, except that compound 18 was used as the second additive instead of compound 12.

[0202] Examples 4-10

[0203] The procedure was the same as in Example 1, except that compound 19 was used as the second additive instead of compound 12.

[0204] Example 4-11

[0205] The procedure was the same as in Example 1, except that compound 20 was used as the second additive instead of compound 12.

[0206] Examples 4 - 12

[0207] The procedure was the same as in Example 1, except that Compound 21 was used as the second additive instead of Compound 12.

[0208] Examples 4 - 13

[0209] The procedure was the same as in Example 1, except that Compound 22 was used as the second additive instead of Compound 12.

[0210] Examples 4 - 14

[0211] The procedure was the same as in Example 1, except that Compound 23 was used as the second additive instead of Compound 12.

[0212] Examples 4 - 15

[0213] The procedure was the same as in Example 1, except that Compound 24 was used as the second additive instead of Compound 12.

[0214] Examples 4 - 16

[0215] The procedure was the same as in Example 1, except that Compound 25 was used as the second additive instead of Compound 12.

[0216] Examples 5 - 1

[0217] The procedure was the same as in Example 1, except that the mass content of the second additive Compound 12 was adjusted to 0.005%.

[0218] Examples 5 - 2

[0219] The procedure was the same as in Example 1, except that the mass content of the second additive Compound 12 was adjusted to 0.05%.

[0220] Examples 5 - 3

[0221] [

[0221] The procedure was carried out in the same manner as in Example 1, except that the mass content of the second additive compound 12 was adjusted to 0.2%.

[0222] Example 5-4

[0223] The procedure was carried out in the same manner as in Example 1, except that the mass content of the second additive compound 12 was adjusted to 4%.

[0224] Example 5-5

[0225] The procedure was the same as in Example 1, except that the mass content of the second additive compound 12 was adjusted to 6%.

[0226] Examples 5-6

[0227] The procedure was carried out in the same manner as in Example 1, except that the mass content of the second additive compound 12 was adjusted to 9%.

[0228] Examples 5-7

[0229] The procedure was carried out in the same manner as in Example 1, except that the mass content of the second additive compound 12 was adjusted to 12%.

[0230] Example 6-1

[0231] The procedure was the same as in Example 1, except that the porosity of the negative electrode material layer in the negative electrode sheet was adjusted to 25%.

[0232] Example 6-2

[0233] The procedure was the same as in Example 1, except that the porosity of the negative electrode material layer in the negative electrode sheet was adjusted to 35%.

[0234] Example 6-3

[0235] The procedure was the same as in Example 1, except that the porosity of the negative electrode material layer in the negative electrode sheet was adjusted to 40%.

[0236] Example 6-4

[0237] The procedure was the same as in Example 1, except that the porosity of the negative electrode material layer in the negative electrode sheet was adjusted to 44%.

[0238] Example 6-5

[0239] The procedure was the same as in Example 1, except that the porosity of the negative electrode material layer in the negative electrode sheet was adjusted to 48%.

[0240] Example 7-1

[0241] The procedure was the same as in Example 1, except that the average particle size Dv50 of the negative electrode active material was adjusted to 3 μm.

[0242] Example 7-2

[0243] The procedure was the same as in Example 1, except that the average particle size Dv50 of the negative electrode active material was adjusted to 6 μm.

[0244] Example 7-3

[0245] The procedure was the same as in Example 1, except that the average particle size Dv50 of the negative electrode active material was adjusted to 8 μm.

[0246] Example 7-4

[0247] The procedure was the same as in Example 1, except that the average particle size Dv50 of the negative electrode active material was adjusted to 15 μm.

[0248] Example 7-5

[0249] The procedure was the same as in Example 1, except that the average particle size Dv50 of the negative electrode active material was adjusted to 20 μm.

[0250] Example 7-6

[0251] The procedure was the same as in Example 1, except that the average particle size Dv50 of the negative electrode active material was adjusted to 25 μm.

[0252] Example 7-7

[0253] The procedure was the same as in Example 1, except that the average particle size Dv50 of the negative electrode active material was adjusted to 28 μm.

[0254] Example 8-1

[0255] The coating amount per unit area (CW) of the negative electrode sheet is 1.5 mg / cm². 2 The procedure was the same as in Example 1, except for the adjustments made.

[0256] Example 8-2

[0257] The coating amount per unit area (CW) of the negative electrode sheet is 3 mg / cm². 2 The procedure was the same as in Example 1, except for the adjustments made.

[0258] Example 8-3

[0259] The coating amount per unit area (CW) of the negative electrode sheet is 6 mg / cm². 2 The procedure was the same as in Example 1, except for the adjustments made.

[0260] Example 8-4

[0261] The coating amount per unit area (CW) of the negative electrode sheet is 12 mg / cm². 2 The procedure was the same as in Example 1, except for the adjustments made.

[0262] Example 8-5

[0263] The coating amount per unit area (CW) of the negative electrode sheet is 15 mg / cm². 2 The procedure was the same as in Example 1, except for the adjustments made.

[0264] Comparative Example 1-1

[0265] The procedure was the same as in Example 1, except that compound 1 as the first additive was removed.

[0266] Comparative Example 1-2

[0267] The procedure was carried out in the same manner as in Example 1, except that compound 12, which was used as the second additive, was removed.

[0268] Comparative Examples 1-3

[0269] The procedure was the same as in Example 1, except that compound 8 was used as the first additive instead of compound 1.

[0270] Performance testing

[0271] 1) Testing of cycle performance at 60°C

[0272] At 60°C, the batteries of each example and comparative example were charged with a constant current of 1C until the voltage reached 3.65V, then charged with a constant voltage of 3.65V until the current became ≤0.05C, and then discharged with a constant current of 1C until the voltage reached 2.5V. This constituted one charge-discharge process, and the discharge capacity at this time was recorded as the discharge capacity of the first cycle of the battery. This charge-discharge cycle was repeated, and the capacity retention rate of the battery after 500 cycles was calculated.

[0273] The capacity retention rate (%) of a battery after 500 cycles at 60°C = (discharge capacity of the battery at 500 cycles / discharge capacity of the battery at 1 cycle) × 100%.

[0274] 2) Test of volume retention rate after storage at 60°C.

[0275] At 25°C, the batteries of the above examples and comparative examples were charged with a constant current of 0.33C until the voltage reached 3.65V, then charged with a constant voltage of 3.65V until the current became ≤0.05C, and finally discharged with a constant current of 0.33C until the voltage reached 2.5V. The actual discharge capacity of the batteries was recorded as C0.

[0276] At 25°C, the battery was charged with a constant current of 0.33C0 until the voltage reached 3.65V, and then charged again with a constant voltage of 3.65V until the current became ≤0.05C0, at which point the battery was fully charged. The fully charged battery was stored in a constant temperature chamber at 60°C for 60 days, and then the battery was removed and a capacity test was performed.

[0277] The capacity retention rate of a battery after being stored at 60°C for 60 days = (discharge capacity of the battery after 60 days of storage / actual discharge capacity of the battery C0) × 100%.

[0278] The results are shown in Table 4.

[0279] [Table 4-1] [Table 4-2]

[0280] The results from Examples 1 and 2-1 to 2-6 and Comparative Examples 1-1 and 1-3 show that introducing a cyclic sulfate ester additive can effectively improve the high-temperature cycle and storage performance of battery cells. Furthermore, compared to conventional sultone additives, the SEI generated by this additive at the negative electrode exhibits lower interfacial impedance and greater stability at high temperatures.

[0281] A comparison of Comparative Examples 1-2 with Examples 1 and 4-1 to 4-16 revealed that the introduction of the second additive significantly improves the cycle and storage performance of battery cells at high temperatures. This is because at high temperatures, LiPF6 decomposes easily, generating HF and causing sustained degradation of SEI. By introducing a phosphate ester or isocyanate additive into the electrolyte, the acid content in the electrolyte is reduced, extending the battery's cycle and storage life at high temperatures.

[0282] From the results of Examples 3-1 to 3-5, it was found that if the amount of the first additive was too small, the improvement effect was not very noticeable, and if the amount of the first additive was too large, a thick SEI was generated at the negative electrode, resulting in increased polarization of the battery cell and a certain degree of deterioration in high-temperature cycle performance and storage performance. When the mass ratio of the cyclic sulfonic acid ester additive of this application in the electrolyte is within the above preferred range, the battery cell has even better cycle and storage performance.

[0283] The results from Examples 5-1 to 5-7 showed that if the amount of the second additive was too small, the improvement effect was not significant, and if the amount of the second additive was too large, the cycle and storage performance at high temperatures deteriorated. When the mass ratio of the second additive of this application in the electrolyte is within the above preferred range, the battery cell has even better cycle and storage performance.

[0284] The results from Examples 6-1 to 6-5 show that if the porosity of the negative electrode material layer on the electrode sheet is too small, the particle structure of the negative electrode active material is destroyed by pressure, making it difficult for the electrolyte to penetrate, increasing polarization, and degrading the long-term cycle performance of the battery cell. When the porosity ratio of the negative electrode active material coating of this application is within the above preferred range, the battery cell can exhibit excellent performance even at high temperatures.

[0285] The results from Examples 7-1 to 7-9 showed that when the Dv50 of the negative electrode active material is too small and the specific surface area is too large, contact between the battery and the electrolyte increases, leading to more vigorous side reactions, accumulation of by-products on the battery surface, increased negative electrode impedance, and consequently, increased capacity loss during high-temperature cycles of the battery. When the Dv50 of the negative electrode active material is within the above preferred range, the battery can exhibit superior performance.

[0286] The results from Examples 8-1 to 8-5 showed that the smaller the coating weight per unit area of ​​the negative electrode sheet, the better the battery's dynamic performance. However, to meet the energy density requirements, a smaller coating weight necessitates a larger coating area, increasing the battery's manufacturing cost. If the coating weight is too large, the transport rate of the electrolyte is hindered, thereby affecting the battery's cycle and storage performance. Therefore, when the coating weight per unit area of ​​the negative electrode sheet is within the above-mentioned preferred range, the battery exhibits good dynamic performance without affecting its energy density or overall performance.

[0287] While this application has been described with reference to preferred embodiments, various improvements can be made thereto without departing from the scope of this application, and components therein can be replaced with equivalents. In particular, each technical feature mentioned in each embodiment can be combined in any manner, provided that there is no structural inconsistency. This application is not limited to the specific embodiments disclosed herein, but includes all technical ideas contained in the claims.

Claims

1. A non-aqueous electrolyte comprising a first additive and a second additive, wherein the first additive is a cyclic sulfate ester compound having a structure represented by general formula (I), 【Chemistry 29】 【Transformation 30】 In general formula (I), Ｒ１ , Ｒ２ , Ｒ３ and Ｒ４ Each of these is independently selected from one of the following: a group having the structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group. In general formula (II), R ５ and R ６ Each of these is independently selected from one of the following: a group having the structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group. R １ and R ２ are not hydrogen atoms at the same time, and R ３ and R ４ are not hydrogen atoms at the same time, The second additive is selected from phosphate ester compounds, isocyanate compounds, or combinations thereof. The phosphate ester compound has a structure represented by general formula (III), 【Chemistry 31】 In general formula (III), R １ , R ２ , R ３ , R ４ , R ５ Each of these is independently selected from one of the following: a group having the structure represented by general formula (IV), a hydrogen atom, a C1-C6 alkyl group, a halogen atom, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C6-C10 aryl group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, a hydroxyl group, a sulfonic acid group, or a tri(C1-C6 alkyl)silyl group. In general formula (IV), R ６ , R ７ , R ８ Each of these is independently selected from one of the following: hydrogen atom, C1-C6 alkyl group, halogen atom, C1-C6 haloalkyl group, C1-C6 alkoxy group, C1-C6 haloalkoxy group, C6-C10 aryl group, C2-C6 alkenyl group, C2-C6 ester group, cyano group, or sulfonic acid group. The isocyanate compound has a structure represented by general formula (V), 【Chemistry 32】 In general formula (V), R １ This is either unsubstituted or with one or more R ａ Selected from C2-C10 alkylene groups, C2-C10 heteroalkylene groups, C6-C18 arylene groups, C2-C18 heteroarylene groups, C3-C18 divalent alicyclic groups, and C3-C18 heterodivalent alicyclic groups, The one or more R ａ Each of these is independently selected from halogen atoms, -CN, -NCO, -OH, -COOH, -SOOH, C2-C10 ester groups, C1-C10 alkyl groups, C2-C10 alkenyl groups, C2-C10 alkynyl groups, and C2-C10 alkoxy groups. A non-aqueous electrolyte in general formula (V), where n is 1, 2, or 3.

2. In the cyclic sulfate ester compound, R １ , R ２ , R ３ and R ４ Each of these is independently selected from one of the following: a group having the structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, and a sulfonic acid group. In the cyclic sulfate ester compound, R ５ and R ６ Each of these is independently selected from one of the following: a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, and a sulfonic acid group. Selectively, in the cyclic sulfate ester compound, R １ , R ２ , R ３ and R ４ Each of these is independently selected from one of the following: a group having the structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, and a cyano group. Selectively, in the cyclic sulfate ester compound, R ５ and R ６ Each is independently selected from either a hydrogen atom or a C1-C3 alkyl group. Selectively, in the cyclic sulfate ester compound, R １ , R ２ , R ３ and R ４ Each of these is independently selected from one of the following: a group having the structure represented by general formula (II), a hydrogen atom, a F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyano group. Selectively, in the cyclic sulfate ester compound, R ５ and R ６ Each of these is independently selected from one of the following: a hydrogen atom, a methyl group, an ethyl group, a propyl group, and an isopropyl group. Selectively, the base of the structure represented by the general formula II) is 【Transformation 33】 One of the following groups is selected, where X is an F atom, a Cl atom, or a Br atom. Selectively, the base of the structure represented by the general formula II) is 【Transformation 34】 One of the following is selected: Selectively, the cyclic sulfate ester compound is 【Chemistry 35】 A non-aqueous electrolyte according to claim 1, selected from one or more of the following compounds.

5. The non-aqueous electrolyte according to any one of claims 1 to 4, wherein the mass content of the cyclic sulfate ester compound is W1, where 0.005% ≤ W1 ≤ 10%, and selectively 0.05% ≤ W1 ≤ 5%.

6. In the phosphate ester compound, R １ , R ２ , R ３ , R ４ , R ５ Each of these is independently selected from one of the following: a group having the structure represented by general formula (IV), a hydrogen atom, a C1-C3 alkyl group, a halogen atom, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C6-C10 aryl group, a C2-C3 alkenyl group, a C2-C3 ester group, a cyano group, a hydroxyl group, a sulfonic acid group, or a tri(C1-C3 alkyl)silyl group. In general formula (IV), R ６ , R ７ , R ８ Each of these is independently selected from one of the following: hydrogen atom, C1-C3 alkyl group, halogen atom, C1-C3 haloalkyl group, C1-C3 alkoxy group, C1-C3 haloalkoxy group, C6-C10 aryl group, C2-C3 alkenyl group, C2-C3 ester group, cyano group, or sulfonic acid group. Selectively, in the phosphate ester compound, R １ , R ２ , R ３ , R ４ , R ５ Each of these is independently selected from one of the following: a group having the structure represented by general formula (IV), a hydrogen atom, a C1-C3 alkyl group, a halogen atom, a C1-C3 alkoxy group, or a tri(C1-C3 alkyl)silyl group. Selectively, in general formula (IV), R ６ , R ７ , R ８ Each of these is independently selected from one of the following: a hydrogen atom, a C1-C3 alkyl group, or a C1-C3 alkoxy group. Selectively, the base of the structure represented by general formula (IV) is 【Transformation 36】 One of the following is selected: Selectively, the phosphate ester compounds are 【Chemistry 37】 A non-aqueous electrolyte according to any one of claims 1 to 5, selected from one or more of the compounds.

7. In the isocyanate compound, R １ This is either unsubstituted or with one or more R ａ Selected from C2-C6 alkylene groups, C2-C6 heteroalkylene groups, C6-C10 arylene groups, C2-C10 heteroarylene groups, C4-C6 divalent alicyclic groups, and C4-C6 heterodivalent alicyclic groups, Selectively, one or more of the above R ａ Each of these is independently selected from halogen atoms, -CN, -NCO, -OH, -COOH, -SOOH, C2-C6 ester groups, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and C2-C6 alkoxy groups. Selectively, one or more of the above R ａ Each of these is independently selected from halogen atoms, -CN, -NCO, -OH, -COOH, -SOOH, C2-C3 ester groups, C1-C3 alkyl groups, C2-C3 alkenyl groups, C2-C3 alkynyl groups, and C2-C3 alkoxy groups. Selectively, in the isocyanate compound, R １ This is either unsubstituted or with one or more R ａ Selected from C2-C6 alkylene groups, C6-C10 arylene groups, and C4-C6 divalent alicyclic groups substituted with, The one or more R ａ Each of these is independently selected from a halogen atom and a C1-C3 alkyl group. Selectively, the isocyanate compounds are 【Transformation 38】 A non-aqueous electrolyte according to any one of claims 1 to 6, selected from one or more of the compounds.

8. The non-aqueous electrolyte according to any one of claims 1 to 7, wherein the mass ratio of the second additive in the non-aqueous electrolyte is W2, where 0.01% ≤ W2 ≤ 10%, selectively 0.1% ≤ W2 ≤ 8%, and selectively 0.3% ≤ W2 ≤ 5%.

9. A secondary battery comprising a non-aqueous electrolyte according to any one of claims 1 to 8, further comprising a positive electrode sheet and a negative electrode sheet, wherein the negative electrode sheet comprises a negative electrode material layer containing a negative electrode active material.

10. The secondary battery according to claim 9, wherein the porosity of the negative electrode material layer is 30% to 45%, and selectively 37% to 42%.

11. The secondary battery according to claim 9 or 10, wherein the average particle size Dv50 of the negative electrode active material is 3 to 25 μm, and selectively 5 μm ≤ Dv50 ≤ 20 μm, and selectively 7 μm ≤ Dv50 ≤ 15 μm.

12. The coating amount per unit area of ​​the negative electrode sheet is CW, which is 2 mg / cm². ２ ≦CW≦13mg / cm ２ , selectively 5 mg / cm ２ ≦CW≦10mg / cm ２ The secondary battery according to any one of claims 9 to 11.

13. A power consumption device comprising a secondary battery including the secondary battery described in any one of claims 9 to 12.

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