Secondary batteries and power consumption devices

Abstract

This application relates to the battery technology, specifically to a secondary battery and a power consumption device. The secondary battery comprises a non-aqueous electrolyte containing a cyclic sulfate ester compound. This application further relates to a power consumption device including the secondary battery. One of the problems that this invention aims to solve is how to reduce the problems of increased impedance and capacity decay in lithium-ion secondary batteries caused by severe polarization and the breakdown of the negative electrode by transition metals during the cycling process, thereby obtaining a lithium-ion secondary battery with excellent cycle performance and a long service life. This application provides a secondary battery and a power consumption device for solving the above problem.

Description

[Technical Field]

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

[0002] As environmental problems worsen daily, the global pursuit of "carbon neutrality" is driving industries to move in a more environmentally friendly and healthier direction. Lithium-ion batteries, as cleaner energy storage devices, are beginning to be widely applied in many fields, including energy storage and power systems such as hydroelectric, thermal, wind, and solar power plants, as well as electric vehicles, military equipment, and aerospace. While the electric vehicle sector has experienced explosive growth since 2015 as a major commercial area for lithium-ion batteries, concerns about consumption due to insufficient driving range are significantly hindering the development of electric vehicles. Improving battery range is an urgent issue that must be addressed in this sector. [Overview of the Initiative]

[0003] The application of high-energy-density active materials is one of the key directions for developing high-energy-density power batteries. Ternary materials have become the first choice for some new energy vehicles seeking longer driving ranges due to their high plateau voltage, higher gram capacity, and higher compaction density. To further improve energy density, researchers continuously increase the nickel content in ternary materials. However, as the nickel content increases, the stability of the material's crystal lattice gradually decreases, making it more susceptible to lattice collapse at high temperatures or during cycling. This is accompanied by the irreversible formation of rock salt and spinel phases on the outside and the leaching of transition metal ions. The rock salt and spinel phases have lower lithium-ion conductivity, leading to increased battery polarization and decreased cycle capacity over long cycles. After leaching, the transition metals migrate and deposit on the surface of the negative electrode, resulting in increased surface impedance and decreased utilization of the negative electrode, thus degrading battery performance. Furthermore, to obtain higher energy density, positive electrode sheets containing ternary materials often employ higher compaction densities. However, higher compaction densities can cause spherical cathode particles to break down into smaller particles, increasing the specific surface area in contact with the electrolyte of the cathode material, thereby exacerbating the problem of metal leaching.

[0004] One of the problems that this invention aims to solve is how to reduce the problems of increased impedance and capacity decay in lithium-ion secondary batteries caused by severe polarization and the breakdown of the negative electrode by transition metals during the cycling process, thereby obtaining a lithium-ion secondary battery with excellent cycling performance and a long service life.

[0005] This application provides a secondary battery and a power consumption device for solving the above problems.

[0006] A first aspect of this application provides a secondary battery comprising a positive electrode sheet and a non-aqueous electrolyte, wherein the non-aqueous electrolyte comprises an additive, the additive comprising a cyclic sulfate ester compound having a structure represented by general formula (I), [ka] [Chemical formula] Here, R 1 , R 2 , R 3 and R 4 are each independently selected from any one of a group having a 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 5 and R 6 are each 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-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 simultaneously, and R 3 and R 4 are not hydrogen atoms simultaneously, The positive electrode sheet includes a positive electrode material layer containing a positive electrode active material. The positive electrode active material includes a ternary positive electrode material. The ternary positive electrode material is a nickel-cobalt-manganese ternary positive electrode material, and its molecular formula is Li 1+a [Ni x Co y Mn z [[ID=No. 39]]M1 b M2 c O 2-d N d . Here, the M1 and M2 elements are independently selected from at least one of Al, Zr, Ti, Mg, Zn, B, Ca, Ce, Te, and Fe, and the N element is selected from at least one of F, Cl, and S. Here, 0.5 ≦ x < 1, 0 < y ≦ 0.3, 0 ≦ z ≦ 0.25, -0.1 < a < 0.2, 0 ≦ b < 0.3, 0 ≦ c < 0.3, 0 ≦ d < 0.2, 0 ≦ b + c < 0.3, and x + y + z + b = 1. The consolidation density of the positive electrode sheet is 3.1 cm 3It is larger than that.

[0007] In some embodiments, 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, 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.

[0008] In some embodiments, 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.

[0009] In some embodiments, R 5 and R 6 Each of these is independently selected from a hydrogen atom and one of the C1-C3 alkyl groups.

[0010] In some embodiments, 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.

[0011] In some embodiments, R 5and 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.

[0012] 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 an F atom, a Cl atom, or a Br atom.

[0013] 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.

[0014] In some embodiments, the cyclic sulfate ester compound is [ka] One or more of the following compounds are selected.

[0015] 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%.

[0016] In some embodiments, the molecular formula of the ternary material is Li[Ni x Co y Mn z ]O2, where 0.5≦x<1, 0 <y≦0.3、0≦z≦0.25、x+y+z=1である。

[0017] In some embodiments, the ternary material is LiNi 0.5 Co 0.3 Mn 0.2 O2, LiLiLi 0.6 Co0.2 Mn 0.2 O2, LiLiLi 0.8 Co 0.1 Mn 0.1 O2 and LiNi 0.9 Co 0.055 Mn 0.055 This includes, but is not limited to, O2.

[0018] In some embodiments, the compaction density of the positive electrode sheet is 3.3 to 4.1 g / cm³. 3 Therefore, selectively 3.4-3.8 g / cm³ 3 That is the case.

[0019] In some embodiments, the average particle size Dv50 of the positive electrode active material is 1 to 25 μm, selectively 2 μm ≤ Dv50 ≤ 20 μm, and selectively 2 μm ≤ Dv50 ≤ 15 μm.

[0020] A second aspect of this application provides a power consumption device including a secondary battery, wherein the secondary battery includes any one of the secondary batteries of the first aspect described above.

[0021] The secondary battery described in this application has improved cycle performance. [Brief explanation of the drawing]

[0022] To more clearly illustrate the technical concept in the embodiments of this application, the drawings necessary for the embodiments of this application are briefly described below. However, it is clear that the drawings described below represent only a few embodiments of this application, and those skilled in the art can obtain other drawings based on these without requiring any creative effort.

[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 using a secondary battery as a power source according to one embodiment of the present application.

[0024] In drawings, the drawings are not drawn to the actual scale. [Explanation of Symbols]

[0025] 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]

[0026] 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 the 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.

[0027] The embodiments specifically disclosing the non-aqueous electrolyte, secondary battery, and power consumption device of this application will be described in detail below, with appropriate reference to the drawings. However, unnecessary details 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.

[0028] 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 range values ​​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.

[0029] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical inventions.

[0030] Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical concepts.

[0031] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably in order. For example, the fact that the method includes steps (a) and (b) means that the method may include steps (a) and (b) performed in order, or steps (b) and (a) performed in order. 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), etc.

[0032] 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.

[0033] 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).

[0034] [Secondary battery]

[0035] A first aspect of this application provides a secondary battery comprising a positive electrode sheet and a non-aqueous electrolyte, wherein the non-aqueous electrolyte comprises an additive, the additive comprising a cyclic sulfate ester compound having a structure represented by general formula (I), [ka] [ka] Here, 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-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 5 and R 6 Each of these is independently selected from one of the following: a group having the structure represented by the 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 At the same time, it is not a hydrogen atom, but R 3 and R 4 At the same time, it is not a hydrogen atom, The positive electrode sheet includes a positive electrode material layer containing a positive electrode active material, the positive electrode active material includes a ternary positive electrode material, the ternary positive electrode material is a nickel-cobalt-manganese ternary positive electrode material, and its molecular formula is Li 1+a [Ni x Co y Mn z M1 b M2 c ]O 2-d N d Here, elements M1 and M2 are independently selected from at least one of Al, Zr, Ti, Mg, Zn, B, Ca, Ce, Te, and Fe, and element N is selected from at least one of F, Cl, and S, where 0.5 ≤ x < 1, 0 <y≦0.3、0≦z≦0.25、-0.1<a<0.2、0≦b<0.3、0≦c<0.3、0≦d<0.2、0≦b+c<0.3、x+y+z+b=1であり、 The compaction density of the positive electrode sheet is 3.1 cm³. 3 It is larger than that.

[0036] 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 discharge. Generally, secondary batteries include 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.

[0037] As mentioned above, ternary materials themselves have problems such as increased cycle impedance and leaching of transition metals. After increasing energy density by adopting high compaction density, the destruction of the negative electrode by transition metals also intensifies. The present invention uses cyclic sulfate esters as an electrolyte additive, which can participate in film formation at the positive and negative electrode interfaces during the initial charging process. Specifically, the main component forming the film at the positive electrode interface is an alkyl lithium sulfate-based organolithium compound, and the main component forming the film at the negative electrode interface is a polymer similar to lithium sulfite and polyethylene oxide (PEO). This additive reduces the film formation impedance at the positive and negative electrode interfaces, produces an inorganic-organic mixed SEI film with higher stability and stronger barrier capability, protects the negative electrode from destruction by transition metals, avoids increased polarization of the battery by reducing the formation of rock salt phase and spinel at the positive electrode interface, and further reduces the increase in impedance during the cycle process, thereby significantly improving the cycle performance of the battery cell.

[0038] [Nonaqueous electrolyte]

[0039] The secondary battery of this application comprises a non-aqueous electrolyte, the non-aqueous electrolyte comprises an additive, the additive comprises a cyclic sulfate ester compound having the structure shown in the general formula (I) above. In the general formula (I) above, the cyclic sulfate ester rings are all five-membered rings, which can form a denser SEI film.

[0040] 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, preventing the SEI film from breaking down in response to volume changes of the negative electrode during the cycle. By introducing substituents containing F and N, it is possible to create an SEI film rich in more inorganic components such as LiF and Li3N that are involved in film formation on the negative electrode, thereby improving the mechanical strength of the SEI film, improving the stability of the negative electrode SEI film, and achieving the objective of further improving battery cycle performance.

[0041] 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 cyclopropyl group, a cyclobutane group, etc. The alkyl group in the above haloalkyl group 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 cyclopropyl group, a cyclobutane 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 of the alkyl groups. One or more hydrogen atoms are substituted on the alkoxy group, and the alkoxy group includes, but is not limited to, a cyclopropane 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 substitutes on 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, and -CH2CH=CH2CH3, and the ester group includes, but is not limited to, a methyl formate group, an ethyl formate group, an ethyl acetate group, a methyl propionate group, an ethyl propionate group, a propyl propionate group, etc.

[0042] In some embodiments, 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, 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.

[0043] In some embodiments, R 1 , R 2 , R 3 and R 4 are each independently selected from any one of a group having a structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, and a cyano group.

[0044] In some embodiments, R 5 and R 6 are each independently selected from any one of a hydrogen atom and a C1-C3 alkyl group.

[0045] In some embodiments, R 1 , R 2 , R 3 and R 4 are each independently selected from any one of a group having a 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.

[0046] In some embodiments, R 5 and R 6 are each independently selected from any one of a hydrogen atom, a methyl group, an ethyl group, a propyl group, and an isopropyl group.

[0047] In some embodiments, the group having the structure represented by the general formula (II) is [Chemical formula] selected from any one of the groups of, where X is a F atom, a Cl atom or a Br atom.

[0048] In some embodiments, the group having the structure represented by the general formula (II) is [Chemical formula] selected from any one of the groups of.

[0049] In some embodiments, the cyclic sulfate compound is [Chemical formula] selected from any one or more of the following compounds.

[0050] The method for producing the cyclic sulfate compound is simpler, more industrially popular and easier to implement, and the improvement effect on the cycle performance of the secondary battery is more stable.

[0051] In some embodiments, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are R 1 and R 2 are simultaneously hydrogen atoms, and one of R 3 and R 4 is a hydrogen atom, and the other is a group having a structure represented by the 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 in the group having a structure represented by the general formula (II), R 5 and R 6 do not satisfy the condition that they are simultaneously hydrogen atoms.

[0052] In some embodiments, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are R 3 and R 4 are simultaneously hydrogen atoms, and R 1 and R 2One 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.

[0053] In some embodiments, R 5 and R 6 Each of these is independently selected from groups other than the structural group represented by general formula (II).

[0054] In the present invention, the content of the cyclic sulfate ester compound in the non-aqueous electrolyte may be arbitrary. 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%. Since the improvement effect on the cycle performance of the cyclic sulfate ester compound within the above content range is more pronounced, the battery cell can have superior performance.

[0055] 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 1%, 1% and 2%, 2% and 3%, 3% and 5%, 5% and 8%, 8% and 10%, 10% and 15%, or greater than 15%.

[0056] In some embodiments, the non-aqueous electrolyte used in the present invention further comprises an electrolyte, and any electrolyte that can be commonly used in non-aqueous electrolytes can be applied to 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 electrolyte, and selectively comprises a lithium salt, and selectively comprises 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 or sodium salts may be used alone or in combination of two or more.

[0057] 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.

[0058] 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 and linear carbonate may be used to improve the load characteristics and low-temperature characteristics of a secondary battery. In some embodiments, EC+EMC (ethylene carbonate + ethyl methyl carbonate) is used as the non-aqueous solvent.

[0059] When the non-aqueous electrolyte of this application is applied to a solid-state battery, a solid solvent such as dimethyl sulfone may be used.

[0060] 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.

[0061] [Method for producing cyclic sulfate ester compounds having the structure represented by general formula (I)]

[0062] 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.

[0063] [Positive electrode sheet]

[0064] The secondary battery according to the present invention includes a positive electrode sheet, the positive electrode sheet includes a positive electrode material layer containing a positive electrode active material, the positive electrode active material includes a nickel-cobalt-manganese ternary positive electrode material, and its molecular formula is Li 1+a [Ni x Co y Mn z M1 b M2 c ]O 2-d N dHere, elements M1 and M2 are independently selected from at least one of Al, Zr, Ti, Mg, Zn, B, Ca, Ce, Te, and Fe, and element N is selected from at least one of F, Cl, and S, where 0.5 ≤ x < 1, 0 <y≦0.3、0≦z≦0.25、-0.1<a<0.2、0≦b<0.3、0≦c<0.3、0≦d<0.2、0≦b+c<0.3、x+y+z+b=1である。

[0065] In some embodiments, the molecular formula of the ternary material is Li[Ni x Co y Mn z ]O2, where 0.5≦x<1, 0 <y≦0.3、0≦z≦0.25、x+y+z=1である。

[0066] In some embodiments, the ternary material is LiNi 0.5 Co 0.3 Mn 0.2 O2, LiLiLi 0.6 Co 0.2 Mn 0.2 O2, LiLiLi 0.8 Co 0.1 Mn 0.1 O2 and LiNi 0.9 Co 0.055 Mn 0.055 This includes, but is not limited to, O2.

[0067] When cyclic sulfate ester compounds are added to a system containing the above-mentioned ternary substance, they can play a role in reducing the increase in lithium-ion cycle impedance and improving cycle performance.

[0068] As mentioned above, to obtain higher energy density, cathode sheets containing ternary materials often employ higher compaction densities. However, higher compaction densities can cause spherical cathode particles to break down into smaller particles, increasing the specific surface area in contact with the electrolyte of the cathode material, thereby exacerbating the problem of metal leaching. Adding cyclic sulfate ester compounds to the electrolyte helps to solve the above problem.

[0069] The cyclic sulfate compound additive used in this invention provides a high compaction density for the positive electrode sheet (for example, a compaction density of 3.1 cm³). 3 It may also be applied to secondary batteries (larger than).

[0070] In some embodiments, the compaction density of the positive electrode sheet is 3.3 to 4.1 g / cm³. 3 , selectively 3.4-3.8 g / cm³ 3 For example, 3.3-3.4 g / cm³ 3 3.4~3.45 g / cm³ 3 3.45~3.5 g / cm³ 3 3.5~3.6 g / cm³ 3 3.6~3.7 g / cm³ 3 3.7~3.8 g / cm³ 3 3.8~3.9 g / cm³ 3 3.9~4.0 g / cm³ 3 Or 4.0-4.1 g / cm³ 3 That is the case.

[0071] The consolidation density may be measured using a consolidation densimeter, and the measurement method may be a method commonly used in the field or a method described in the consolidation densimeter's manual.

[0072] The reason why the particle size distribution of a ternary material affects its compaction density is related to the spherical topography of the ternary material. When spheres of the same diameter are stacked, there are many gaps between the spheres, and if there are no appropriately small-sized particles to fill these gaps, the bulk density will be very low. Therefore, a proper particle size distribution can improve the compaction density of the material. The particle size of the material may also be expressed as Dv50, where Dv50 refers to the particle size corresponding 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 positive electrode active material used in the present invention is 1 to 25 μm, selectively 2 μm ≤ Dv50 ≤ 20 μm and selectively 2 μm ≤ Dv50 ≤ 15 μm. When the Dv50 of the positive electrode active material is within the above preferred range, it is possible to reduce polarization on the positive electrode side while ensuring high compaction density, thereby ensuring good battery performance.

[0073] 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 5 μm, 5 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.

[0074] 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.

[0075] A positive electrode sheet typically includes a positive electrode current collector and a positive electrode material layer installed on at least one surface of the positive electrode current collector.

[0076] For example, a positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode material layer is installed on one or both of the two opposing surfaces of the positive electrode current collector.

[0077] 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)).

[0078] In some embodiments, the positive electrode material layer may further include other positive electrode active materials. Positive electrode active materials for batteries known in the art 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 are 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, 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.

[0079] In some embodiments, the positive electrode film 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.

[0080] 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.

[0081] 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.

[0082] [Negative electrode sheet]

[0083] The secondary battery of the present invention may further include a negative electrode sheet. The negative electrode sheet may include a negative electrode current collector and a negative electrode film layer (negative electrode material layer) installed on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0084] 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 one or both of the two opposing surfaces of the negative electrode current collector.

[0085] 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)).

[0086] 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.

[0087] 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).

[0088] 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.

[0089] In some embodiments, the negative electrode film layer further selectively comprises other auxiliary agents, such as thickeners (e.g., sodium carboxymethylcellulose (CMC-Na)).

[0090] 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.

[0091] [Separator]

[0092] 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.

[0093] 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 are not particularly limited.

[0094] 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.

[0095] In some embodiments, the secondary battery may include an outer casing. This casing may be used to package the electrode assembly and electrolyte.

[0096] 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.

[0097] 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.

[0098] In some embodiments, referring to Figure 2, the casing may include a case 51 and a cover plate 53. Here, the casing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates surrounding each other to form 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 specifically select them according to their actual needs.

[0099] 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.

[0100] 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 manner. Furthermore, these multiple secondary batteries 5 can be fixed in place by fasteners.

[0101] Selectively, the battery module 4 may further include a housing having a housing space, in which a plurality of secondary batteries 5 are housed.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] The aforementioned power consumption device can be selected from a secondary battery, battery module, or battery pack depending on the usage demand.

[0106] 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]

[0107] [Examples]

[0108] 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 instruments used is not specified, they are all commercially available common products, and information on the remaining reagents or compounds is recorded in Table 1.

[0109] [Table 1-1] [Table 1-2]

[0110] Synthesis example

[0111] 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.

[0112] Synthesis example 1: Compound 1 [ka] synthesis

[0113] 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 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 1.

[0114] 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 ppm5.42-5.39(m,2H), 5.36-5.34(m,2H), 1.67-1.65(d,6H).

[0115] Synthesis example 2: Compound 2 [ka] synthesis

[0116] 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 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 2.

[0117] 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.

[0118] Synthesis example 3: Compound 3 [ka] synthesis

[0119] 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 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 3.

[0120] 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%).

[0121] Furthermore, for the synthesis methods of the following compounds, refer to Synthesis Example 1, and use the corresponding substrates in Table 2 instead of 1,6-dideoxygalactitol.

[0122] [Table 2]

[0123] Synthesis example 4: Compound 5 [ka] synthesis

[0124] Step 1: Add 392.4 g (2 mol) of solid 1,2,3,4,5,6-heptahexol 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 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 4.

[0125] 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.

[0126] Furthermore, for the synthesis methods of the following compounds, refer to Synthesis Example 4, and use the corresponding substrates in Table 3 instead of 1,2,3,4,5,6--heptanehexaol.

[0127] [Table 3]

[0128] Synthesis example 5: Compound 7 [ka] synthesis

[0129] 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.

[0130] 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.

[0131] Example 1

[0132] Electrolyte composition: Compound 1 was used as an 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.

[0133] Manufacturing of positive electrode sheets:

[0134] Cathode active material LiNi 0.5 Co 0.3 Mn 0.2 O2 (average particle size Dv50 of 8 μm), conductive agent acetylene black, and adhesive polyvinylidene fluoride (PVDF) were dissolved in the solvent N-methylpyrrolidone (NMP) in a weight ratio of 97:1:2. 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 a positive electrode sheet was obtained through drying, cold pressing, and slitting. The compaction density of the positive electrode sheet was 3.45 g / cm³. 3 That is the case.

[0135] Dv50 of the positive electrode active material refers to the particle size corresponding to when the cumulative volume percentage of the positive 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. of the UK, and the particle size distribution was measured in accordance with the particle size distribution laser diffraction method GB / T19077-2016 to obtain Dv50.

[0136] The compaction density of the positive electrode sheet can be measured using a compaction density meter.

[0137] Manufacturing of negative electrode sheets:

[0138] A negative electrode slurry was prepared by dissolving graphite 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 one or more times, and a negative electrode sheet was obtained by drying, cold pressing, and slitting.

[0139] Separator:

[0140] A conventional polypropylene film was used as the separator.

[0141] Lithium-ion battery assembly:

[0142] 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.

[0143] Example 2-1

[0144] This is the same as Example 1, except that Compound 1 is replaced with Compound 2.

[0145] Example 2-2

[0146] This is the same as Example 1, except that compound 1 is replaced with compound 3.

[0147] Examples 2-3

[0148] This is the same as Example 1, except that compound 1 is replaced with compound 4.

[0149] Examples 2-4

[0150] This is the same as Example 1, except that compound 1 is replaced with compound 5.

[0151] Examples 2-5

[0152] This is the same as Example 1, except that compound 1 is replaced with compound 6.

[0153] Examples 2-6

[0154] This is the same as Example 1, except that compound 1 is replaced with compound 7.

[0155] Example 3-1

[0156] The procedure is the same as in Example 1, except that the mass content of compound 1 was adjusted to 0.001%.

[0157] Example 3-2

[0158] The procedure is the same as in Example 1, except that the mass content of compound 1 was adjusted to 0.01%.

[0159] Example 3-3

[0160] The procedure is the same as in Example 1, except that the mass content of compound 1 was adjusted to 3%.

[0161] Examples 3-4

[0162] The procedure is the same as in Example 1, except that the mass content of compound 1 was adjusted to 8%.

[0163] Examples 3-5

[0164] The procedure is the same as in Example 1, except that the mass content of compound 1 was adjusted to 15%.

[0165] Example 4-1

[0166] Cathode active material LiNi 0.6 Co 0.2 Mn 0.2 Using O2 as the positive electrode active material LiNi 0.5 Co 0.3 Mn 0.2 This is the same as Example 1, except that O2 was replaced.

[0167] Example 4-2

[0168] Cathode active material LiNi 0.8 Co 0.1 Mn 0.1 Using O2 as the positive electrode active material LiNi 0.5 Co 0.3 Mn 0.2 This is the same as Example 1, except that O2 was replaced.

[0169] Example 4-3

[0170] Cathode active material LiNi 0.9 Co 0.055 Mn 0.055 Using O2 as the positive electrode active material LiNi 0.5 Co 0.3 Mn 0.2 This is the same as Example 1, except that O2 was replaced.

[0171] Example 5-1

[0172] The procedure is the same as in Example 1, except that the average particle size of the positive electrode active material was adjusted to 0.5 μm.

[0173] Example 5-2

[0174] It is the same as Example 1 except that the average particle size of the positive electrode active material is adjusted to 1.5 μm.

[0175] Example 5-3

[0176] It is the same as Example 1 except that the average particle size of the positive electrode active material is adjusted to 5 μm.

[0177] Example 5-4

[0178] It is the same as Example 1 except that the average particle size of the positive electrode active material is adjusted to 18 μm.

[0179] Example 5-5

[0180] It is the same as Example 1 except that the average particle size of the positive electrode active material is adjusted to 22 μm.

[0181] Example 5-6

[0182] It is the same as Example 1 except that the average particle size of the positive electrode active material is adjusted to 30 μm.

[0183] Comparative Example 1-1

[0184] It is the same as Example 1 except that Compound 1 is not added.

[0185] Comparative Example 1-2

[0186] It is the same as Example 1 except that Compound 1 is replaced with Compound 8.

[0187] Comparative Example 1-3

[0188] Without adding Compound 1 and using the positive electrode active material LiNi 0.6 Co 0.2 Mn 0.2 O2 to use the positive electrode active material LiNi 0.5 Co 0.3 Mn0.2 This is the same as Example 1, except that O2 was replaced.

[0189] Comparative Example 1-4

[0190] Without adding compound 1, and using LiNi as the positive electrode active material. 0.8 Co 0.1 Mn 0.1 Using O2 as the positive electrode active material LiNi 0.5 Co 0.3 Mn 0.2 This is the same as Example 1, except that O2 was replaced.

[0191] Comparative Examples 1-5

[0192] Without adding compound 1, and using LiNi as the positive electrode active material. 0.9 Co 0.055 Mn 0.055 Using O2 as the positive electrode active material LiNi 0.5 Co 0.3 Mn 0.2 This is the same as Example 1, except that O2 was replaced.

[0193] 1) Testing of cycle performance at 45°C

[0194] At 45°C, the lithium-ion battery was charged with a constant current of 1C to a voltage of 4.25V, then charged again with a constant voltage of 4.25V to a current of ≤0.05C, allowed to stand for 5 minutes, and then discharged with a constant current of 1C to a voltage of 2.8V. This constitutes one charge-discharge cycle, and the discharge capacity recorded is that of the first cycle. Multiple charge-discharge cycle tests were performed on the lithium-ion battery according to the above method until the discharge capacity of the lithium-ion secondary battery decreased to 80%, and the number of cycles of the lithium-ion battery was recorded.

[0195] Battery capacity retention rate (%) after N cycles at 45℃ = (Discharge capacity of the battery in the Nth cycle / Discharge capacity of the battery in the first cycle) × 100%.

[0196] 2) Increase in DCR after cycling at 45°C

[0197] At room temperature, the lithium-ion battery was charged to 4.25V with a constant current of 1C, and then charged at a constant voltage of 4.25V with a current of 0.05C. After the battery was fully charged, it was left standing for 5 minutes, discharged at 1C for 30 minutes (until the battery cell's charge reached 50% SOC), and then left standing for another 5 minutes. The temperature was adjusted to 25°C, and the battery was left standing for 1 hour, during which the voltage V1 of the battery cell was recorded. Discharge was performed at 4C for 30 seconds, and the voltage V2 after pulse discharge was recorded. The DCR when the battery cell was discharged at 50% SOC for 30 seconds is (V1-V2) / I, and I=4C. The increase in the battery's DCR after cycling to 80% at 45°C is (DCR of the battery after 80% storage cycle / DCR of the battery before cycling) × 100%.

[0198] The test results are recorded in Table 4.

[0199] [Table 4]

[0200] As can be seen from the results of Examples 1 and 2-1 to 2-6 and Comparative Examples 1-1 and 1-2, the cyclic sulfate ester compound forms a film on the positive and negative electrode sides, reducing the film formation impedance at the positive and negative electrode interface, and generating an inorganic-organic mixed SEI film with higher stability and stronger blocking ability. This avoids an increase in battery polarization, further reduces the increase in impedance during the cycle process, and significantly improves the cycle performance of the battery cell. In addition, compared to conventional sultone additives, the SEI generated on the negative electrode by the additive used in this application has higher stability and superior effects.

[0201] As can be seen from the results of Examples 3-1 to 3-5, if the amount of the cyclic sulfate compound is too small, there is no obvious improvement effect. If the amount of the cyclic sulfate compound is too large, the films formed on the positive electrode and the negative electrode are thick. As a result, the polarization of the battery cell increases, which affects the cycle performance of the battery cell to some extent. When the mass ratio of the cyclic sulfonic acid ester additive used in the present application in the electrolytic solution is within the above-mentioned preferred range, the battery cell can have good performance.

[0202] As can be seen from the results of Examples 4-1 to 4-3 and Comparative Examples 1-3 to 1-5, for ternary systems with different metal contents, such as LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.9 Co 0.55 Mn 0.55 O2, by adding a cyclic sulfate compound, the increase in the cycle impedance of lithium ions can be reduced, and the cycle performance can be improved.

[0203] As can be seen from the results of Examples 5-1 to 5-6, if the Dv50 of the positive electrode active material is too small and its BET specific surface area becomes excessively large, the contact between the electrode and the electrolytic solution increases, the interfacial side reaction intensifies, and the cycle impedance of the battery cell increases. On the contrary, if the Dv50 is too high, the particles become too large and there are many gaps. As a result, the tap density of the electrode sheet becomes too low. Therefore, when the Dv50 of the positive electrode active material is within the above-mentioned preferred range, it is possible to reduce the polarization on the positive electrode side while ensuring a high tap density, and ensure good battery performance.

[0204] 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 secondary battery comprising a positive electrode sheet and a non-aqueous electrolyte, wherein the non-aqueous electrolyte comprises an additive, and the additive comprises a cyclic sulfate ester compound having a structure represented by general formula (I), [Chemistry 18] 【Chemistry 19】 Here, 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-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 ５ and R ６ Each of these is independently selected from one of the following: a group having the structure represented by the 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 positive electrode sheet includes a positive electrode material layer containing a positive electrode active material, the positive electrode active material includes a ternary positive electrode material, the ternary positive electrode material is a nickel-cobalt-manganese ternary positive electrode material, and its molecular formula is Li １＋ａ [Ni ｘ Co ｙ Mn ｚ M1 ｂ M2 ｃ ]O ２－ｄ N ｄ Here, elements M1 and M2 are independently selected from at least one of Al, Zr, Ti, Mg, Zn, B, Ca, Ce, Te, and Fe, and element N is selected from at least one of F, Cl, and S, where 0.5 ≤ x < 1, 0 < y ≤ 0.3, 0 ≤ z ≤ 0.25, -0.1 < a < 0.2, 0 ≤ b < 0.3, 0 ≤ c < 0.3, 0 ≤ d < 0.2, 0 ≤ b + c < 0.3, and x + y + z + b = 1. The compaction density of the positive electrode sheet is 3.1 cm³. ３ A rechargeable battery that is larger than that.

2. 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. 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, 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, R ５ and R ６ Each is independently selected from a hydrogen atom and one of the C1-C3 alkyl groups. Selectively, 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, 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 【Chemistry 20】 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 【Chemistry 21】 A secondary battery according to claim 1, wherein one of the following bases is selected.

3. In the above additive, the cyclic sulfate ester compound is 【Chemistry 22】 A secondary battery according to claim 1 or 2, wherein one or more of the following compounds are selected.

4. The secondary battery according to any one of claims 1 to 3, wherein 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%.

5. The molecular formula of the aforementioned ternary material is Li[Ni ｘ Co ｙ Mn ｚ ]O ２ Here, 0.5 ≤ x < 1, 0 < y ≤ 0.3, 0 ≤ z ≤ 0.25, and x + y + z = 1. Selectively, the ternary material is LiNi ０．５ Co ０．３ Mn ０．２ O ２ LiNi ０．６ Co ０．２ Mn ０．２ O ２ LiNi ０．８ Co ０．１ Mn ０．１ O ２ and LiNi ０．９ Co ０．０５５ Mn ０．０５５ O ２ A secondary battery according to any one of claims 1 to 4, including but not limited to the above.

6. The compaction density of the positive electrode sheet is 3.3 to 4.1 g / cm³. ３ Therefore, selectively 3.4 to 3.8 g / cm³ ３ A secondary battery according to any one of claims 1 to 5.

7. The secondary battery according to any one of claims 1 to 6, wherein the average particle size Dv50 of the positive electrode active material is 1 to 25 μm, and selectively 2 μm ≤ Dv50 ≤ 20 μm and selectively 2 μm ≤ Dv50 ≤ 15 μm.

8. A power consumption device including a secondary battery, wherein the secondary battery includes the secondary battery described in any one of claims 1 to 7.

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