Secondary batteries and power consumption devices

Abstract

This application provides a secondary battery and a power consumption device. The secondary battery of this application comprises a negative electrode sheet and a non-aqueous electrolyte, the negative electrode sheet comprising a negative electrode active material having a volume average particle size Dv50 of 6 to 20 μm, the non-aqueous electrolyte comprising an additive and a non-aqueous solvent, the additive comprising a cyclic sulfate ester compound represented by formula (I), and the non-aqueous solvent comprising ethylene carbonate. Thus, this application forms a non-aqueous electrolyte using an ethylene carbonate solvent and an additive and combines it with a negative electrode active material of a certain particle size. JPEG2026518375000042.jpg4569

Description

[Technical Field]

[0001] This application relates to the field of lithium battery technology, and more particularly to secondary batteries and power consumption devices. [Background technology]

[0002] In recent years, as the range of applications for rechargeable batteries has expanded, they are widely used in energy storage and power systems such as hydroelectric power plants, thermal power plants, wind power plants, and solar power plants, as well as in many fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace. Due to the significant advancements made in rechargeable batteries, the requirements for their cycle performance, storage performance, and safety performance have also increased. [Overview of the Initiative]

[0003] This application was made in view of the above-mentioned problems, and its purpose is to provide a secondary battery and a power consumption device. The secondary battery of this application improves the cycle performance and storage performance of the battery and reduces the amount of gas generated during battery cycling by using an ethylene carbonate solvent and additives in combination with a negative electrode active material of a certain particle size.

[0004] To achieve the above objective, a first aspect of this application provides a secondary battery comprising a negative electrode sheet and a non-aqueous electrolyte, wherein the negative electrode sheet comprises a negative electrode active material having a volume average particle size Dv50 of 6 to 20 μm, selectively 8 to 15 μm, and the non-aqueous electrolyte comprises an additive and a non-aqueous solvent, wherein the non-aqueous solvent comprises ethylene carbonate.

[0005] The aforementioned additive includes a cyclic sulfate ester compound represented by formula (I), [ka] Here, R 1 , R 2 , R 3 and R 4is independently selected from any one of a group having a structure represented by the 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, n1 and n2 are each independently an arbitrary integer from 0 to 2,

Chemical formula

[0006] This invention involves forming a non-aqueous electrolyte using an ethylene carbonate solvent and additives, and combining it with a negative electrode active material of a specific particle size. During the initial charging process of the battery, the ethylene carbonate and additives form an inorganic-organic mixed SEI film on the negative electrode surface that is more stable and has stronger electron-blocking ability. This suppresses gas generation due to the reaction between the electrolyte and the negative electrode, thereby reducing the amount of gas generated during battery cycling, improving cycle performance and storage performance. The negative electrode active material of a specific particle size also contributes to improving the battery's cycle performance. Furthermore, ethylene carbonate can promote the dissociation of lithium salts in the electrolyte, improving the conductivity of the electrolyte.

[0007] In any embodiment, the cyclic sulfate ester compound has the structure represented by formula (I-1), [ka] R 1 , R 2 , R 3 and R 4 Each of these is independently selected from any one of the following: a group having the structure represented by formula (II-1), 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. [ka] R 5 and R 6 Each of these is independently selected from any one of the following: 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.

[0008] In the above general formula (I-1), the cyclic sulfate ester rings are all five-membered rings, which can form a denser SEI film. Compared to six-membered rings, they have greater ring strain and are easier to form a film at the negative electrode. In contrast, six-membered rings have less ring strain and higher stability, but film formation at the negative electrode is slower, resulting in lower efficiency in generating an electron-blocking SEI film and affecting the effectiveness of the SEI film.

[0009] In any embodiment, R 1 , R 2 , R 3 and R 4 Each of these is independently selected from any one of the following: a group having a structure represented by general formula (II-1), 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, and a cyano group, R 5 and R 6 Each of these is independently selected from any 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, and a cyano group. Selectively, R 1 , R 2 , R 3 and R 4 Each of these is independently selected from any one of the following: a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, and a cyano group, R 5 and R 6Each of these is independently selected from any 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, and a cyano group. More selectively, R 1 , R 2 , R 3 and R 4 Each of these is independently selected from any one of the following: a group having a structure represented by general formula (II-1), a hydrogen atom, a F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a trifluoromethyl group, an ethoxy group, and a cyano group, R 5 and R 6 Each of these is independently selected from any one of the following: hydrogen atom, F atom, Cl atom, Br atom, methyl group, ethyl group, propyl group, isopropyl group, trifluoromethyl group, ethoxy group, and cyano group. More selectively, the group of the structure represented by the general formula (II-1) is selected from any one of the following groups: [ka] Here, X is a F atom, a Cl atom, or a Br atom.

[0010] In any embodiment, R 1 , R 2 , R 3 and R 4 Each independently [ka] A hydrogen atom, a fluorine atom, a chlorine atom, a brinol atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a trifluoromethyl group, an ethoxy group, and a cyano group are selected from any one of these, and X is a fluorine atom. Selectively, R 1 , R 2 , R 3 and R 4 Each independently [ka] X is selected from any one of the following: hydrogen atom, fluorine atom, methyl group, ethyl group, propyl group, trifluoromethyl group, ethoxy group, and cyano group, and X is a fluorine atom.

[0011] In any embodiment, the cyclic sulfate ester compound is selected from the following compounds: [ka]

[0012] The above method for preparing cyclic sulfate ester compounds is simple, advantageous for industrial dissemination and implementation, and provides a more stable improvement in battery cycle performance.

[0013] In any embodiment, the mass content of the additive in the non-aqueous electrolyte is 0.001% to 20%, selectively 0.0025% to 16.7%, more selectively 0.005% to 10%, and even more selectively 0.05% to 5%.

[0014] When the mass content of additives in the non-aqueous electrolyte is within the above range, the stability and electron-blocking capability of the SEI film on the negative electrode surface can be further enhanced, thereby further improving the battery's cycle performance and storage performance, and further reducing the amount of gas generated during battery cycling.

[0015] In any embodiment, the mass content of the ethylene carbonate in the non-aqueous solvent is 5% to 60%, selectively 10% to 50%, and more selectively 20% to 40%.

[0016] When the mass content of ethylene carbonate in the non-aqueous solvent is within the above range, it is possible to improve the battery's cycle performance and storage performance, reduce the amount of gas generated during battery cycling, and is advantageous for increasing the conductivity of the electrolyte, thereby improving the battery's rapid charging performance.

[0017] In any embodiment, the volume-average particle size Dv50 of the negative electrode active material and the mass content W1 of the additive in the non-aqueous electrolyte satisfy 0.001 ≤ W1 × 1000 / Dv50 ≤ 20, and selectively 0.0025 ≤ W1 × 1000 / Dv50 ≤ 16.7, where the unit of volume-average particle size Dv50 is μm.

[0018] When the above conditions are met, on the one hand, the active ion transport performance and electron transport performance of the negative electrode active material are higher, and the powder pressure density of the negative electrode active material is also higher. On the other hand, side reactions between the electrolyte and the negative electrode are reduced, the amount of gas generated during battery cycling is reduced, and the battery's cycle performance and storage performance are improved.

[0019] In any embodiment, the Raman shift is 1360 cm². -1 The intensity of the peak of the negative electrode active material in is I D The Raman shift was 1585 cm. -1 The intensity of the peak of the negative electrode active material in is I G And, I D / I G ≤0.5, selectively I D / I G ≤0.25, more selectively 0.1 ≤ I D / I G The value is ≤ 0.2.

[0020] I of the negative electrode active material D / I G When the above range is present, it is advantageous to improve the surface stability of the negative electrode active material, reduce side reactions between the electrolyte and the negative electrode, thereby reducing the volume expansion of the battery during the cycle process, improving the battery's cycle performance, and improving its storage performance.

[0021] In any embodiment, the secondary battery is a lithium-ion secondary battery.

[0022] A second aspect of this application provides a power consumption device, the power consumption device including a battery according to the first aspect of this application. [Brief explanation of the drawing]

[0023] [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 that uses a secondary battery as a power source according to one embodiment of the present application. [Explanation of symbols]

[0024] 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]

[0025] The embodiments of the secondary battery, battery module, battery pack, and power consumption device disclosed in this application will be described in detail below, with appropriate reference to the drawings. 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 accompanying drawings and the following explanation are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0026] 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 a shortened expression for 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.

[0027] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical inventions.

[0028] Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical concepts.

[0029] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably in order. For example, if a method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, if a method described above may further include step (c), it 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.

[0030] Unless otherwise specified, the terms "include" and "inclusive" as used in this application may be open or closed. For example, "include" and "inclusive" may include or include other components not listed, or may include or include only the listed components.

[0031] 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).

[0032] Unless otherwise specified, in this application the term "halogen" refers to atoms of Group VIIA elements, including fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).

[0033] Unless otherwise specified, in this application the term "C1-C6 alkyl group" refers to a linear or branched alkyl group containing 1 to 6 carbon atoms, specifically including C1-C3 alkyl groups, C2-C4 alkyl groups, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, or n-hexyl group.

[0034] Unless otherwise specified, in this application the term "C1-C6 haloalkyl group" refers to a C1-C6 alkyl group in which one or more H atoms are substituted with halogens, where the definitions of "C1-C6 alkyl group" and "halogen" are as stated above. Specifically, this includes C1-C3 haloalkyl groups, C2-C4 haloalkyl groups, such as monofluoromethyl groups, difluoromethyl groups, trifluoromethyl groups, and 2,2,2-trifluoroethyl groups.

[0035] Unless otherwise specified, in this application, the term "C1-C6 alkoxy group" refers to a C1-C6 alkyl-O- group, and "C1-C6 alkyl group" is as described above. Non-limiting examples of suitable C1-C6 alkoxy groups include methoxy, ethoxy, and isopropoxy groups.

[0036] Unless otherwise specified, in this application, the term "C1-C6 haloalkoxy group" refers to a C1-C6 alkoxy group in which one or more H atoms are substituted with halogens, and the definitions of "C1-C6 alkoxy group" and "halogen" are as stated above. Specifically, this includes C1-C3 haloalkoxy groups, C2-C4 haloalkoxy groups, such as difluoromethoxy groups, trifluoromethoxy groups, and 2,2,2-trifluoroethoxy groups.

[0037] Unless otherwise specified, in this application the term "C2-C6 alkenyl group" refers to a monovalent hydrocarbon group that contains 2 to 6 carbon atoms and has at least one unsaturated carbon-carbon double bond, and specifically includes C2-C5 alkenyl groups, C2-C4 alkenyl groups, such as ethylene, propylene, n-butene, isobutylene, n-pentene, isopentene, etc.

[0038] Unless otherwise specified, in this application, the term "C2-C6 ester group" refers to -COO-C1-C6 alkyl groups, where "C1-C6 alkyl group" is as described above. Specifically, this includes C2-C5 ester groups, C2-C4 ester groups, such as -COOCH3 and -COOCH2CH3.

[0039] [Secondary battery]

[0040] Secondary batteries, also known as rechargeable batteries or storage batteries, are batteries that can be used continuously by reactivating the active material through charging after they have been discharged.

[0041] 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) move back and forth between the positive and negative electrode sheets, undergoing intercalation and deintercalation. The separator is placed between the positive and negative electrode sheets and primarily serves to prevent short circuits between the positive and negative electrodes, while also allowing active ions to pass through. The electrolyte primarily serves to conduct active ions between the positive and negative electrode sheets.

[0042] One embodiment of the present application provides a secondary battery. The secondary battery includes a negative electrode sheet and a non-aqueous electrolyte. The negative electrode sheet contains a negative electrode active material, and the volume average particle diameter Dv50 of the negative electrode active material is 6 to 20 μm, optionally 8 to 15 μm. For example, it is in the range consisting of 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 12 μm, 13 μm, 15 μm, 17 μm, 18 μm, 20 μm and any value therebetween. The non-aqueous electrolyte contains an additive and a non-aqueous solvent, and the non-aqueous solvent contains ethylene carbonate.

[0043] The additive contains a cyclic sulfate compound represented by formula (I).

Chemical formula

Chemical formula

[0044] Although the mechanism is not clear, the applicant has unexpectedly discovered the following, and this application describes forming a non-aqueous electrolyte using an ethylene carbonate solvent and additives, and combining it with a negative electrode active material of a certain particle size. During the initial charging process of the battery, the ethylene carbonate and additives form an inorganic-organic mixed SEI film on the negative electrode surface that is more stable and has stronger electron-blocking ability. This suppresses gas generation due to the reaction between the electrolyte and the negative electrode, thereby reducing the amount of gas generated during battery cycling, improving cycle performance and storage performance. The negative electrode active material of a certain particle size also contributes to improving the battery's cycle performance. Furthermore, ethylene carbonate can promote the dissociation of lithium salts in the electrolyte, improving the conductivity of the electrolyte.

[0045] The volume-average particle size Dv50 represents the particle size at which the cumulative volume distribution of the negative electrode active material reaches 50%. In some embodiments, the volume-average particle size Dv50 is measured using instruments and methods known in the art. For example, it can be measured using a laser particle size analyzer (e.g., Master Size 300), referring to the GB / T 19077-2016 particle size distribution laser diffraction method.

[0046] In some embodiments, the cyclic sulfate ester compound has a structure represented by formula (I-1), [ka] R 1 , R 2 , R 3 and R 4 Each of these is independently selected from any one of the following: a group having the structure represented by formula (II-1), 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. [ka] R 5 and R 6Each of these is independently selected from any one of the following: 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.

[0047] In the above general formula (I-1), the cyclic sulfate ester rings are all five-membered rings, which can form a denser SEI film. Compared to six-membered rings, they have greater ring strain and are easier to form a film at the negative electrode. In contrast, six-membered rings have less ring strain and higher stability, but film formation at the negative electrode is slower, resulting in lower efficiency in generating an electron-blocking SEI film and affecting the effectiveness of the SEI film.

[0048] In some embodiments, R 1 , R 2 , R 3 and R 4 Each of these is independently selected from any one of the following: a group having a structure represented by general formula (II-1), 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, and a cyano group, R 5 and R 6 Each of these is independently selected from any 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, and a cyano group. Selectively, R 1 , R 2 , R 3 and R 4 Each of these is independently selected from any one of the following: a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, and a cyano group, R 5 and R 6 Each of these is independently selected from any 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, and a cyano group. More selectively, R 1 , R2 , R 3 and R 4 Each of these is independently selected from any one of the following: a group having a structure represented by general formula (II-1), a hydrogen atom, a F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a trifluoromethyl group, an ethoxy group, and a cyano group, R 5 and R 6 Each of these is independently selected from any one of the following: hydrogen atom, F atom, Cl atom, Br atom, methyl group, ethyl group, propyl group, isopropyl group, trifluoromethyl group, ethoxy group, and cyano group. More selectively, the group of the structure represented by the general formula (II-1) is selected from any one of the following groups: [ka] Here, X is a F atom, a Cl atom, or a Br atom.

[0049] In some embodiments, R 1 , R 2 , R 3 and R 4 Each independently [ka] A hydrogen atom, a fluorine atom, a chlorine atom, a brinol atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a trifluoromethyl group, an ethoxy group, and a cyano group are selected from any one of these, and X is a fluorine atom. Selectively, R 1 , R 2 , R 3 and R 4 Each independently [ka] X is selected from any one of the following: hydrogen atom, fluorine atom, methyl group, ethyl group, propyl group, trifluoromethyl group, ethoxy group, and cyano group, and X is a fluorine atom.

[0050] In some embodiments, the cyclic sulfate ester compound is selected from the following compounds: [ka]

[0051] The above method for preparing cyclic sulfate ester compounds is simple, advantageous for industrial dissemination and implementation, and provides a more stable improvement in battery cycle performance.

[0052] The numbers of the above compounds are shown in the table below. [Table 4-1] [Table 4-2] [Table 4-3]

[0053] For a method of preparing cyclic sulfate ester compounds having the structure represented by general formula (I) of this application, refer to the following synthetic 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, etc. Here, R 1 , R 2 , R 3 , R 4 The definitions of n1 and n2 are as described above.

[0054] In some embodiments, the mass content of the additive in the non-aqueous electrolyte is in the range of 0.001% to 20%, selectively 0.0025% to 16.7%, more selectively 0.005% to 10%, even more selectively 0.05% to 5%, for example, 0.001%, 0.0025%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 0.8%, 1%, 2%, 3%, 5%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 15%, 16.7%, 18%, 19%, 20%, and any of the above values.

[0055] When the mass content of additives in the non-aqueous electrolyte is within the above range, the stability and electron-blocking capability of the SEI film on the negative electrode surface can be further enhanced, thereby further improving the battery's cycle performance and storage performance, and further reducing the amount of gas generated during battery cycling.

[0056] In some embodiments, the mass content of the ethylene carbonate in the non-aqueous solvent is in the range of 5% to 60%, selectively 10% to 50%, more selectively 20% to 40%, for example, 5%, 10%, 20%, 30%, 40%, 50%, 60%, and any of the above values.

[0057] When the mass content of ethylene carbonate in the non-aqueous solvent is within the above range, it is possible to improve the battery's cycle performance and storage performance, reduce the amount of gas generated during battery cycling, and is advantageous for increasing the conductivity of the electrolyte, thereby improving the battery's rapid charging performance.

[0058] In some embodiments, the volume-average particle size Dv50 of the negative electrode active material and the mass content W11 of the additive in the non-aqueous electrolyte satisfy 0.001 ≤ W1 × 1000 / Dv50 ≤ 20, and selectively 0.0025 ≤ W1 × 1000 / Dv50 ≤ 16.7, for example, W1 × 1000 / Dv50 is in the range of 0.001, 0.002, 0.0025, 0.005, 0.01, 0.05, 0.08, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 and any of the above values. Here, the unit of volume-average particle size Dv50 is μm.

[0059] When the above conditions are met, on the one hand, the active ion transport performance and electron transport performance of the negative electrode active material are higher, and the powder pressure density of the negative electrode active material is also higher. On the other hand, side reactions between the electrolyte and the negative electrode are reduced, the amount of gas generated during battery cycling is reduced, and the battery's cycle performance and storage performance are improved.

[0060] In some embodiments, the Raman shift is 1360 cm². -1 The intensity of the peak of the negative electrode active material in is I D The Raman shift was 1585 cm. -1 The intensity of the peak of the negative electrode active material in is I G And, I D / I G ≤0.5, selectively I D / I G ≤0.25, more selectively 0.1 ≤ I D / I G ≤ 0.2, for example, I D / I G This range consists of 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, and any of the above values.

[0061] I of the negative electrode active material D / I GWhen the above range is present, it is advantageous to improve the surface stability of the negative electrode active material, reduce side reactions between the electrolyte and the negative electrode, thereby reducing the volume expansion of the battery during the cycle process, improving the battery's cycle performance, and improving its storage performance.

[0062] In some embodiments, the negative electrode active material is I D / I G The test is performed using conventional methods in this field. For example, the negative electrode active material is measured using a laser micro-Raman spectrometer (for example, using a solid-state laser with a wavelength of 523 nm, a beam diameter of 1.2 μm, and an output of 1 mW as the light source, employing macro-Raman as the measurement mode, and using a CCD detector). The negative electrode active material is pressed onto a sheet, multiple points are randomly selected on the sheet for testing, and the average value is taken to obtain the Raman spectrum. Raman shift 1360 cm⁻¹ -1 The intensity of the scattering peak at position is I D It states that the Raman shift was 1580cm. -1 The intensity of the scattering peak at position is I G It was written, I D / I G Calculate.

[0063] In some embodiments, the secondary battery is a lithium-ion secondary battery.

[0064] [Positive electrode sheet]

[0065] A positive electrode sheet typically includes a positive electrode current collector and a positive electrode film layer placed on at least one surface of the positive electrode current collector, the positive electrode film layer containing a positive electrode active material.

[0066] For example, a positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode film layer is installed on one or both of the two opposing surfaces of the positive electrode current collector.

[0067] In some embodiments, the positive electrode current collector can be a metal foil sheet or a composite current collector. For example, aluminum foil can be used as the metal foil sheet. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (such as aluminum, aluminum 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)).

[0068] In some embodiments, the positive electrode active material can be any positive electrode active material for batteries known in the art. 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 0.2O2(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 0.05 The 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.

[0069] In some embodiments, the positive electrode film layer further selectively 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.

[0070] In some embodiments, the cathode film 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.

[0071] In some embodiments, a positive electrode sheet can be manufactured by the following method: 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, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is applied to a positive electrode current collector; and after processes such as drying and cold pressing, a positive electrode sheet is obtained.

[0072] [Negative electrode sheet]

[0073] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer placed on at least one surface of the negative electrode current collector, the negative electrode film layer containing a negative electrode active material.

[0074] For example, the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode film layer is installed on either one or both of the two opposing surfaces of the negative electrode current collector.

[0075] In some embodiments, the negative electrode current collector can be a metal foil sheet or a composite current collector. For example, copper foil can be used as the metal foil sheet. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (such as copper, copper 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)).

[0076] In some embodiments, the negative electrode active material can be any negative electrode active material for batteries known in the art. For example, the negative electrode active material may include at least one material such as 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.

[0077] In some embodiments, the negative electrode film layer further selectively comprises 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).

[0078] In some embodiments, the negative electrode film 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.

[0079] In some embodiments, the negative electrode film layer further selectively comprises other auxiliary agents, such as thickeners (e.g., sodium carboxymethylcellulose (CMC-Na)).

[0080] 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.

[0081] [Electrolyte]

[0082] The electrolyte plays a role in ion conduction between the positive electrode sheet and the negative electrode sheet.

[0083] In some embodiments, the electrolyte comprises an electrolyte salt and other solvents.

[0084] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluoride phosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoride arsenate, lithium bisfluorosulfonylimide, lithium bistrifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium bisoxalate borate, lithium difluorobisoxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0085] In some embodiments, the other solvent may be selected from at least one of methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0086] In some embodiments, the electrolyte may further selectively include other additives. For example, it may include a positive electrode film-forming additive, and may further include additives that can improve certain aspects of the battery's performance, such as an additive that improves the battery's overcharge performance, or an additive that improves the battery's high-temperature or low-temperature performance.

[0087] [Separator]

[0088] In some embodiments, the secondary battery also includes a separator. This application does not particularly limit the type of separator, and any well-known porous separator with good chemical and mechanical stability can be selected.

[0089] 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. If the separator is a multilayer composite film, the materials of each layer may be the same or different, and is not particularly limited.

[0090] In some embodiments, the positive electrode sheet, negative electrode sheet, and separator can be fabricated into an electrode assembly by a winding process or a lamination process.

[0091] In some embodiments, the secondary battery may include an outer casing. This casing may be used to package the electrode assembly and electrolyte.

[0092] 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.

[0093] In this application, the shape of the secondary battery is not particularly limited and may be cylindrical, rectangular, or any other shape. For example, Figure 1 shows a secondary battery 5 with a rectangular structure as an example.

[0094] 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 surrounding 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 sheet, negative electrode sheet and separator can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is packaged within the housing cavity. The electrolyte permeates 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 select according to their actual specific needs.

[0095] 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.

[0096] 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 arranged sequentially along the longitudinal direction of the battery module 4. Of course, they may be arranged in any other way. Furthermore, these multiple secondary batteries 5 can be fixed in place by fasteners.

[0097] Selectively, the battery module 4 may further include a housing having a housing space, in which a plurality of secondary batteries 5 are housed.

[0098] In some embodiments, the battery modules may be further assembled into a battery pack, and 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.

[0099] 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 able to be covered by a lid on the lower housing 3 and forming a sealed space for housing the battery modules 4. The plurality of battery modules 4 may be arranged inside the battery box in any way.

[0100] Furthermore, this application 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.), trains, ships and satellites, energy storage systems, etc.

[0101] As a power consumption device, a secondary battery, battery module, or battery pack can be selected depending on the usage requirements.

[0102] 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]

[0103] [Examples]

[0104] Examples of the present application are described below. The examples described below are illustrative and are for interpretive purposes only, and should not be understood as limiting the present application. 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.

[0105] [Table 1]

[0106] Preparation Example 1: Compound 1 [ka] synthesis

[0107] Step 1: Add 300 g (2 mol) of solid 1,6-dideoxygalactitol to a 2 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 the intermediate product.

[0108] 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.

[0109] 1H-NMR, CD3CN, δ ppm5.42-5.39(m,2H),5.36-5.34(m,2H),1.67-1.65(d,6H).

[0110] Preparation Example 2: Compound 2 [ka] synthesis

[0111] Step 1: Add 356.5 g (2 mol) of solid 3,4,5,6-octanetetraol to a 2 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 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 the intermediate product.

[0112] Step 2: Add 216.2 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 for 10 minutes at 10-20°C, 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.

[0113] Preparation Example 3: Compound 3 [ka] synthesis

[0114] Step 1: Add 328.4 g (2 mol) of solid 2,3,4,5-heptanetetraol to a 2 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 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 mixture, 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 the intermediate product.

[0115] Step 2: Add 205 g (0.8 mol) of intermediate product 1 to a 2 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%).

[0116] Preparation Example 4: Compound 9 [ka] synthesis

[0117] Instead of 1,6-dideoxygalactitol [ka] (CAS number: 7460-93-7) was used, and the rest was the same as in Preparation Example 1. Compound LC-MS: 285.25.

[0118] Preparation Example 5: Compound 11 [ka] synthesis

[0119] Step 1: Add 392.4 g (2 mol) of solid 1,2,3,4,5,6-heptanehexaol to a 2 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 the intermediate product.

[0120] Step 2: Add 140 g (0.4 mol) of intermediate product 1 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, and within 1 hour add 1500 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 11.

[0121] Preparation Example 6: Compound 14 [ka] synthesis

[0122] Step 1: Add 484 g (2 mol) of solid octitol to a 2 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 the intermediate product.

[0123] Step 2: Add 183.2 g (0.4 mol) of the intermediate product 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 14.

[0124] For the preparation methods of compounds 4-8, 10, and 12-13, refer to the above preparation examples and the preparation methods for compounds of the general formula.

[0125] Example 1

[0126] (1) Preparation of electrolyte: In an argon-atmosphere glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), the organic solvents ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were uniformly mixed in a volume ratio of 3 / 7. Next, 2% (mass percentage in the electrolyte) of additive compound 1-1 and 12.5% ​​(mass percentage in the electrolyte) of LiPF6 were added and dissolved in the organic solvent, and the mixture was stirred until homogeneous to obtain the electrolyte.

[0127] (2) Preparation of negative electrode sheet: The negative electrode active material graphite, the conductive agent carbon black, the adhesive styrene-butadiene rubber (SBR), and the thickener sodium carboxymethylcellulose (CMC-Na) were dissolved in deionized water as a solvent in a mass ratio of 90:4:4:2 and mixed uniformly to prepare a negative electrode slurry. The negative electrode slurry was uniformly applied to the copper foil of the negative electrode current collector in one or more applications, and the negative electrode sheet was obtained by drying, cold pressing, and slitting.

[0128] (3) Preparation of positive electrode sheet: 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, and thoroughly stirred to mix uniformly and obtain a positive electrode slurry. Next, the positive electrode slurry was uniformly applied to the positive electrode current collector, and a positive electrode sheet was obtained by drying, cold pressing, and slitting.

[0129] (4) Separator: A conventional polypropylene membrane was used as the separator.

[0130] (5) Assembly of the secondary battery: The positive electrode sheet, separator, and negative electrode sheet described above are stacked in order, the separator is placed between the positive electrode sheet and the negative electrode sheet to act as an insulator, and the assembly is wound to obtain the electrode assembly. The electrode assembly is placed in the battery case, dried, and then the electrolyte is injected. After processes such as chemical formation and standing are carried out to obtain the secondary battery.

[0131] The manufacturing methods for Examples 2-33 and Comparative Examples 1-4 are similar to the manufacturing method for the secondary battery in Example 1, with details of the different product parameters shown in Table 2. Here, the unit of the volume-average particle size Dv50 in W1×1000 / Dv50 is μm.

[0132] [Table 2-1] [Table 2-2]

[0133] Material testing and battery testing

[0134] (1) Test of volume-average particle size Dv50:

[0135] The measurements were taken using a Mastersizer 2000E laser particle size analyzer manufactured by Malvern Instruments, UK, in accordance with GB / T 19077-2016 "Particle Size Distribution Laser Diffraction Method".

[0136] (2) I of the negative electrode active material D / I G test:

[0137] The negative electrode active material was measured using a LabRAM HR Evolution type laser micro-Raman spectrometer. Here, a solid-state laser with a wavelength of 523 nm, a beam diameter of 1.2 μm, and an output of 1 mW was used as the light source, macro-Raman was adopted as the measurement mode, and a CCD detector was used. The negative electrode active material powder was pressed onto a sheet, and three points were randomly selected on the sheet and tested, and the average value was taken.

[0138] Raman shift 1360cm -1 The intensity of the scattering peak at position is I D It states that the Raman shift was 1580cm. -1 The intensity of the scattering peak at position is I G It was written, I D / I G I calculated it.

[0139] (3) Test of cycle performance at 60°C

[0140] The secondary battery was first completely discharged at 1C at 60°C before being tested. The test procedure was as follows: the secondary battery was charged at 60°C with a constant current of 0.5C to a voltage of 3.65V, then charged at a constant voltage of 3.65V with a current of 0.05C, left to stand for 5 minutes, and then discharged at a constant current of 0.5C to a voltage of 2.5V. This constitutes one charge-discharge cycle, and the discharge capacity recorded here is the discharge capacity of the first cycle. Multiple charge-discharge tests were performed on the secondary battery according to the above method, and the cycle capacity retention rate of the secondary battery was calculated according to the following formula until the cycle capacity retention rate decreased to 80%, and the number of cycles of the secondary battery was recorded.

[0141] The cycle capacity retention rate (%) of a secondary battery = (discharge capacity of the secondary battery in the Nth cycle / discharge capacity of the secondary battery in the first cycle) × 100%.

[0142] (4) Testing of storage performance:

[0143] Under constant temperature conditions of 25°C, the secondary battery was charged to 3.65V at 0.33C, then discharged to 2.5V at 0.33C, and the discharge capacity D1 was tested. The secondary battery was stored under constant temperature conditions of 60°C and removed for testing every 30 days. Each time the secondary battery was removed for testing, it was cooled to 25°C, and the secondary battery was first charged to 3.65V at 0.33C, then discharged to 2.5V at 0.33C, and the discharge capacity was tested. The number of days of storage and the discharge capacity for each test were recorded, and a graph was created with the number of days of storage on the X axis and the discharge capacity on the Y axis to obtain the number of days of storage at which the discharge capacity decreased to 80% of D1.

[0144] (5) Test of volume expansion coefficient:

[0145] The secondary battery was tested by completely discharging it at 1C at 25°C. The test procedure was as follows: the secondary battery was charged to a voltage of 3.65V with a constant current of 0.5C, then charged to a current of 0.05C with a constant voltage of 3.65V, left to stand for 5 minutes, and then discharged to a voltage of 2.5V with a constant current of 0.5C. This constituted one charge-discharge cycle, and the discharge capacity measured was the discharge capacity of the first cycle. The volume V1 of the battery at this time was tested using the water displacement method. Subsequently, the secondary battery underwent multiple charge-discharge cycles according to the above method, and the cycle capacity retention rate of the secondary battery was calculated according to the following formula until the cycle capacity retention rate decreased to 80%. The cycle was then terminated, the secondary battery was placed in a 25°C environment, and the volume V2 of the secondary battery was tested using the water displacement method. The volume expansion rate of the secondary battery was calculated according to the following formula.

[0146] The cycle capacity retention rate (%) of a secondary battery = (discharge capacity of the secondary battery in the Nth cycle / discharge capacity of the secondary battery in the first cycle) × 100%.

[0147] Volume expansion rate of a secondary battery (%) = 100% × (V2 - V1) / V1

[0148] The results of (1) to (2) above are shown in Table 1, and the results of (3) to (5) are shown in Table 3.

[0149] [Table 3-1] [Table 3-2]

[0150] From the above results, we can conclude the following:

[0151] Compared to Comparative Example 1, the batteries of Examples 1 to 10 of this application have higher cycle performance and storage performance, and less gas generation during cycling. Compared to Comparative Example 2, the batteries of Examples 11 to 13 of this application have higher cycle performance and storage performance, and less gas generation during cycling. Compared to Comparative Examples 3 to 4, the batteries of Examples 1 and 15 to 18 of this application have higher cycle performance and storage performance, and less gas generation during cycling. This indicates that the cycle performance and storage performance of the secondary batteries of this application have been significantly improved, and the amount of gas generated during cycling has been significantly reduced.

[0152] Compared to Comparative Examples 23 and 28, the batteries of Examples 1, 19-20 of this application have higher cycle performance and storage performance, and generate less gas during cycling. Compared to Examples 24 and 32, the cycle performance of the batteries of Examples 1, 19-20 of this application is further improved.

[0153] Compared to Comparative Example 30, the batteries of Examples 1, 21-22 of this application have higher cycle performance and storage performance, and generate less gas during cycling.

[0154] Compared to Comparative Example 33, the batteries of Examples 1, 25-27 of this application have higher cycle performance and storage performance, and generate less gas during cycling.

[0155] It should be noted that this application is not limited to the embodiments described above. The embodiments described above are merely examples, and any embodiment that has substantially the same configuration as the technical idea and produces the same effects within the scope of the technical proposal of this application is included within the scope of the technical proposal. Furthermore, other forms that are constructed by adding various modifications to the embodiments that a person skilled in the art could conceive of, and by combining some of the components of the embodiments, are also included within the scope of this application, without departing from the spirit of this application.

Claims

1. A secondary battery comprising a negative electrode sheet and a non-aqueous electrolyte, wherein the negative electrode sheet comprises a negative electrode active material, the volume average particle size Dv50 of the negative electrode active material being 6 to 20 μm, selectively 8 to 15 μm, and the non-aqueous electrolyte comprises an additive and a non-aqueous solvent, the non-aqueous solvent comprising ethylene carbonate. The aforementioned additive includes a cyclic sulfate ester compound represented by formula (I), 【Chemistry 25】 Here, R １ , R ２ , R ３ and R ４ Each of the following is independently selected from a group having the structure represented by 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, and n1 and n2 are each independently any integer from 0 to 2. 【Chemistry 26】 R ５ and R ６ Each of these is independently selected from any one of the following: 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, and n3 is any integer from 0 to 2. 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, Or, R １ , R ２ , R ３ , R ４ , R ５ and R ６ The following conditions are met, R １ and R ２ It is also a hydrogen atom, R ３ and R ４ One of the atoms is a hydrogen atom, and the other is any 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 R in the group having the structure represented by general formula (II). ５ and R ６ However, it is not a hydrogen atom at the same time. Or, R １ , R ２ , R ３ , R ４ , R ５ and R ６ The following conditions are met, R ３ and R ４ It is also a hydrogen atom, R １ and R ２ One of the atoms is a hydrogen atom, and the other is any 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 R in the group having the structure represented by general formula (II). ５ and R ６ A secondary battery that is not composed of hydrogen atoms at the same time.

2. The cyclic sulfate ester compound has the structure shown in formula (I-1), 【Chemistry 27】 R １ , R ２ , R ３ and R ４ Each of these is independently selected from any one of the following: a group having the structure represented by formula (II-1), 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. 【Chemistry 28】 R ５ and R ６ The secondary battery according to claim 1, wherein each of the following is independently selected from any one of 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.

3. R １ , R ２ , R ３ and R ４ Each of these is independently selected from any one of the following: a group having a structure represented by general formula (II-1), 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, and a cyano group, R ５ and R ６ Each of these is independently selected from any 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, and a cyano group. Selectively, R １ , R ２ , R ３ and R ４ Each of these is independently selected from any one of the following: a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, and a cyano group, R ５ and R ６ Each of these is independently selected from any 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, and a cyano group. More selectively, R １ , R ２ , R ３ and R ４ Each of these is independently selected from any one of the following: a group having a structure represented by general formula (II-1), a hydrogen atom, a F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a trifluoromethyl group, an ethoxy group, and a cyano group, R ５ and R ６ Each of these is independently selected from any one of the following: hydrogen atom, F atom, Cl atom, Br atom, methyl group, ethyl group, propyl group, isopropyl group, trifluoromethyl group, ethoxy group, and cyano group. Furthermore, the group of the structure represented by the general formula (II-1) is selected from any one of the following groups: 【Chemistry 29】 The secondary battery according to claim 2, wherein X is an F atom, a Cl atom, or a Br atom.

4. R １ , R ２ , R ３ and R ４ Each independently 【Transformation 30】 A hydrogen atom, a fluorine atom, a chlorine atom, a brin atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a trifluoromethyl group, an ethoxy group, and a cyano group are selected from any one of these, and X is a fluorine atom. Selectively, R １ , R ２ , R ３ and R ４ Each independently 【Chemistry 31】 A secondary battery according to any one of claims 1 to 3, wherein X is an atom selected from any one of a hydrogen atom, a fluorine atom, a methyl group, an ethyl group, a propyl group, a trifluoromethyl group, an ethoxy group, and a cyano group, and X is a fluorine atom.

5. The aforementioned cyclic sulfate ester compound is 【Chemistry 32】 A secondary battery according to any one of claims 1 to 4, selected from the following compounds.

6. The secondary battery according to any one of claims 1 to 5, wherein the mass content of the additive in the non-aqueous electrolyte is 0.001% to 20%, selectively 0.0025% to 16.7%, more selectively 0.005% to 10%, and even more selectively 0.05% to 5%.

7. The secondary battery according to any one of claims 1 to 6, wherein the mass content of the ethylene carbonate in the non-aqueous solvent is 5% to 60%, selectively 10% to 50%, and more selectively 20% to 40%.

8. The volume-average particle size Dv50 of the negative electrode active material and the mass content W of the additive in the non-aqueous electrolyte. １ 0.001 ≤ W １ ×1000 / Dv50 ≤ 20, selectively 0.0025 ≤ W １ A secondary battery according to any one of claims 1 to 7, wherein ×1000 / Dv50 ≤ 16.7, where the unit of the volume-average particle size Dv50 is μm.

9. Raman shift 1360cm －１ The intensity of the peak of the negative electrode active material in is I Ｄ The Raman shift was 1580 cm. －１ The intensity of the peak of the negative electrode active material in is I Ｇ And, I Ｄ / I Ｇ ≤ 0.5, selectively I Ｄ / I Ｇ ≤ 0.25, more selectively 0.1 ≤ I Ｄ / I Ｇ A secondary battery according to any one of claims 1 to 8, wherein the coefficient of the battery is ≤ 0.

2.

10. The secondary battery according to any one of claims 1 to 9, wherein the secondary battery is a lithium secondary battery.

11. A power consumption device comprising a secondary battery according to any one of claims 1 to 10.

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