CN-122025798-A - Nonaqueous electrolyte, and secondary battery, battery module, battery pack, and power consumption device including same

CN122025798ACN 122025798 ACN122025798 ACN 122025798ACN-122025798-A

Abstract

A nonaqueous electrolyte, and a secondary battery, a battery module, a battery pack, and an electric device including the same. The nonaqueous electrolyte solution contains an electrolyte salt, a nonaqueous solvent, and a first additive, the electrolyte salt includes lithium difluorosulfimide, lithium tetrafluoroborate, and lithium difluorooxalato borate, the first additive includes fluoroethylene carbonate, and the content A1 of lithium difluorosulfimide, the content A2 of lithium tetrafluoroborate, the content A3 of lithium difluorooxalato borate, and the content B1 of fluoroethylene carbonate satisfy that A1 is 9% to 15%, A3 is 0.01% to 0.45%, A1/A2 is 30 to 1500, A1/B1 is 3.6 to 15, and A2/A3 is 0.02 to 30, based on the total mass of the nonaqueous electrolyte solution. The secondary battery containing the nonaqueous electrolyte solution has good cycle performance, storage performance, safety performance and dynamic performance.

Inventors

WU ZELI
HAN CHANGLONG

Assignees

宁德时代新能源科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20220520

Claims (15)

1. A nonaqueous electrolyte solution comprising an electrolyte salt, a nonaqueous solvent and a first additive, wherein, The electrolyte salt includes: lithium bis (fluorosulfonyl imide) having a mass content of A1 in the nonaqueous electrolytic solution based on the total mass of the nonaqueous electrolytic solution; Lithium tetrafluoroborate, the mass content of which in the nonaqueous electrolyte is A2, based on the total mass of the nonaqueous electrolyte; Lithium difluorooxalato borate, the mass content of which in the nonaqueous electrolyte is A3, based on the total mass of the nonaqueous electrolyte; The first additive comprises: fluoroethylene carbonate having a mass content of B1 in the nonaqueous electrolytic solution based on the total mass of the nonaqueous electrolytic solution; The nonaqueous electrolyte satisfies the following conditions: The mass content A1 of the lithium bis (fluorosulfonyl) imide in the nonaqueous electrolytic solution is 9% to 15%, The mass content A3 of the lithium difluorooxalato borate in the nonaqueous electrolytic solution is 0.01 to 0.45 percent, The ratio of the mass content A1 of lithium bis (fluorosulfonyl) imide in the nonaqueous electrolytic solution to the mass content A2 of lithium tetrafluoroborate in the nonaqueous electrolytic solution is 30 to 1500, The ratio of the mass content A1 of lithium bis (fluorosulfonyl) imide in the nonaqueous electrolytic solution to the mass content B1 of fluoroethylene carbonate in the nonaqueous electrolytic solution is 3.6 to 15, The ratio of the mass content A2 of lithium tetrafluoroborate in the nonaqueous electrolytic solution to the mass content A3 of lithium difluorooxalato borate in the nonaqueous electrolytic solution is 0.02 to 30.
2. The nonaqueous electrolytic solution according to claim 1, wherein, The ratio of the mass content A1 of lithium difluorosulfimide in the nonaqueous electrolytic solution to the mass content A2 of lithium tetrafluoroborate in the nonaqueous electrolytic solution is 50 to 250, optionally 50 to 150, and/or, The ratio of the mass content A1 of lithium bisfluorosulfonyl imide in the nonaqueous electrolytic solution to the mass content B1 of fluoroethylene carbonate in the nonaqueous electrolytic solution is 4 to 9, optionally 4 to 7, and/or The ratio of the mass content A2 of lithium tetrafluoroborate in the nonaqueous electrolytic solution to the mass content A3 of lithium difluorooxalato borate in the nonaqueous electrolytic solution is 0.5 to 13.5, alternatively 1 to 10.
3. The nonaqueous electrolyte according to claim 1 or 2, wherein the nonaqueous electrolyte further satisfies: The ratio of the sum of the mass content A2 of lithium tetrafluoroborate in the nonaqueous electrolytic solution and the mass content A3 of lithium difluorooxalate borate in the nonaqueous electrolytic solution to the mass content B1 of fluoroethylene carbonate in the nonaqueous electrolytic solution is 0.008 to 0.8, optionally 0.026 to 0.2.
4. The nonaqueous electrolytic solution according to any one of claims 1 to 3, wherein the nonaqueous electrolytic solution satisfies at least one of the following conditions (1) to (4): (1) The mass content A1 of the lithium bis (fluorosulfonyl) imide in the nonaqueous electrolytic solution is 10% to 15%, alternatively 10% to 13%; (2) The mass content A2 of lithium tetrafluoroborate in the nonaqueous electrolytic solution is 0.01% to 0.3%, alternatively 0.05% to 0.2%; (3) The mass content A3 of the lithium difluorooxalato borate in the nonaqueous electrolytic solution is 0.01 to 0.3%, alternatively 0.015 to 0.1%; (4) The mass content B1 of fluoroethylene carbonate in the nonaqueous electrolytic solution is 1.0% to 2.5%, alternatively 1.5% to 2.5%.
5. The nonaqueous electrolyte according to any one of claims 1 to 4, wherein the nonaqueous solvent comprises: A first solvent comprising at least one of ethylene carbonate, propylene carbonate, butylene carbonate, in a mass content of C1 in the nonaqueous solvent, based on the total mass of the nonaqueous solvent; A second solvent comprising at least one of methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, and ethylpropyl carbonate, the mass content of which in the nonaqueous solvent is C2, based on the total mass of the nonaqueous solvent; a third solvent including at least one of methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, the mass content of which in the nonaqueous solvent is C3 based on the total mass of the nonaqueous solvent, The nonaqueous solvent satisfies that the mass content C1 of the first solvent in the nonaqueous solvent is 10% to 30%, the mass content C2 of the second solvent in the nonaqueous solvent is 50% to 90%, the mass content C3 of the third solvent in the nonaqueous solvent is 0% to 20%, Optionally, the ratio of the mass content C1 of the first solvent in the non-aqueous solvent to the sum of the mass content C2 of the second solvent in the non-aqueous solvent and the mass content C3 of the third solvent in the non-aqueous solvent is 0.1 to 0.45, more optionally 0.2 to 0.3.
6. The nonaqueous electrolytic solution according to any one of claims 1 to 5, wherein the nonaqueous electrolytic solution further comprises a second additive comprising at least one of vinylene carbonate, vinyl sulfate, and 1, 3-propane sultone, and the mass content thereof in the nonaqueous electrolytic solution is B2, and B2 is 0.05% to 2%, alternatively 0.5% to 2%, based on the total mass of the nonaqueous electrolytic solution.
7. The nonaqueous electrolytic solution according to claim 6, wherein a ratio of a sum of a mass content A1 of lithium difluorosulfimide in the nonaqueous electrolytic solution and a mass content B2 of the second additive in the nonaqueous electrolytic solution to a mass content C1 of the first solvent in the nonaqueous solvent is 0.4 to 1.3, optionally 0.4 to 0.8.
8. The nonaqueous electrolytic solution according to any one of claims 1 to 7, wherein the nonaqueous electrolytic solution further comprises a third additive comprising at least one of sulfamic acid and a salt thereof in a mass content of B3 in the nonaqueous electrolytic solution of 0.005 to 0.1%, optionally 0.005 to 0.05% based on the total mass of the nonaqueous electrolytic solution.
9. A secondary battery comprising a positive electrode sheet, a negative electrode sheet, and a nonaqueous electrolytic solution, wherein the nonaqueous electrolytic solution is the nonaqueous electrolytic solution according to any one of claims 1 to 8.
10. The secondary battery according to claim 9, wherein the nonaqueous electrolyte has a room temperature conductivity of x mS/cm, the negative electrode tab has a thickness of L μm, and the secondary battery satisfies that L≤120× 。
11. The secondary battery according to claim 9 or 10, wherein the positive electrode sheet comprises a layered material of the formula Li a Ni b Co c Mn d Al e M f O g A h , M represents a transition metal site-doped cation, a represents an oxygen site-doped anion, 0.8≤a≤1.2, 0≤b≤1, 0≤c≤1, 0≤d≤1, 0≤f≤0.2, 0≤g≤2, 0≤h≤2, b+c+d+e+f=1, g+h=2.
12. The secondary battery according to claim 11, wherein Li a Ni b Co c Mn d Al e M f O g A h satisfies at least one of the following conditions (1) to (8): (1) M is at least one selected from Si, ti, mo, V, ge, se, zr, nb, ru, pd, sb, ce, te and W; (2) A is selected from at least one of F, N, P and S, optionally, A is selected from F; (3) 0< b <0.98, alternatively 0.50≤b <0.98; (4)c=0; (5) 0<c +.0.20, optionally, 0<c is less than or equal to 0.10; (6) d=0 and 0< e <0.50, alternatively d=0 and 0<e +.0.10; (7) e=0 and 0< d <0.50, alternatively e=0 and 0<d +.0.10; (8) 0< d <0.50 and 0< e <0.50, alternatively 0<d≤0.30 and 0<e≤0.10.
13. A battery module comprising the secondary battery according to any one of claims 9 to 12.
14. A battery pack comprising one of the secondary battery according to any one of claims 9 to 12, the battery module according to claim 13.
15. An electric device comprising at least one of the secondary battery according to any one of claims 9 to 12, the battery module according to claim 13, and the battery pack according to claim 14.

Description

Nonaqueous electrolyte, and secondary battery, battery module, battery pack, and power consumption device including same The application is based on the application of the application number 202280012715.1, the application date of 2022, the application date of 05 and 20, the application date of Ningde New energy science and technology Co., ltd, the application name of which is 'nonaqueous electrolyte solution', and secondary batteries, battery modules, battery packs and power utilization devices comprising the same. Technical Field The application belongs to the technical field of batteries, and particularly relates to a nonaqueous electrolyte, a secondary battery, a battery module, a battery pack and an electric device comprising the nonaqueous electrolyte. Background In recent years, secondary batteries are widely used in energy storage power supply systems such as hydraulic power, thermal power, wind power and solar power stations, and in various fields such as electric tools, electric bicycles, electric motorcycles, electric automobiles, military equipment, aerospace, and the like. With the application and popularization of secondary batteries, the comprehensive performance of the secondary batteries is receiving more and more attention, for example, the secondary batteries need to meet the requirements of high energy density, long cycle life, high safety performance, good multiplying power performance and the like at the same time. The nonaqueous electrolyte plays a role of conducting ions between the positive electrode and the negative electrode, which is one of the key factors affecting the performance of the secondary battery, and thus, it is highly demanded to provide a nonaqueous electrolyte having good overall performance. Disclosure of Invention The application aims to provide a nonaqueous electrolyte, a secondary battery, a battery module, a battery pack and an electric device comprising the nonaqueous electrolyte, which can ensure that the secondary battery has good cycle performance, storage performance, hot box safety performance and dynamic performance. The first aspect of the application provides a nonaqueous electrolyte comprising an electrolyte salt, a nonaqueous solvent and a first additive, wherein the electrolyte salt comprises lithium bis (fluorosulfonyl) imide, the mass content of which in the nonaqueous electrolyte is A1, based on the total mass of the nonaqueous electrolyte; the lithium tetrafluoroborate electrolyte comprises a lithium tetrafluoroborate, wherein the mass content of the lithium tetrafluoroborate electrolyte in the nonaqueous electrolyte is A2 based on the total mass of the nonaqueous electrolyte, the mass content of the lithium difluoroborate electrolyte in the nonaqueous electrolyte is A3 based on the total mass of the nonaqueous electrolyte, the first additive comprises fluoroethylene carbonate, the mass content of the lithium tetrafluoroborate electrolyte in the nonaqueous electrolyte is B1 based on the total mass of the nonaqueous electrolyte, the nonaqueous electrolyte satisfies that the mass content A1 of the lithium difluorosulfimide in the nonaqueous electrolyte is 9-15%, the mass content A3 of the lithium difluoroborate electrolyte in the nonaqueous electrolyte is 0.01-0.45%, the ratio of the mass content A1 of the lithium difluorosulfimide in the nonaqueous electrolyte to the mass content A2 of the lithium tetrafluoroborate electrolyte is 30-1500, the ratio of the mass content A1 of the lithium difluorosulfimide in the nonaqueous electrolyte to the mass content A2 of the fluoroethylene carbonate in the nonaqueous electrolyte is 30-1500, and the ratio of the mass content A3 of the lithium difluorosulfimide in the nonaqueous electrolyte to the nonaqueous electrolyte is 3.02-3. The inventors of the present application have found through extensive studies that by employing lithium tetrafluoroborate, lithium difluoroborate and fluoroethylene carbonate in a nonaqueous electrolyte containing lithium difluoroborate as a main lithium salt and reasonably adjusting the content A1 of lithium difluoroborate, the content A2 of lithium tetrafluoroborate, the content A3 of lithium difluoroborate and the content B1 of fluoroethylene carbonate so that they satisfy A1 of 9% to 15%, A3 of 0.01% to 0.45%, A1/A2 of 30 to 1500, A1/B1 of 3.6 to 15 and A2/A3 of 0.02 to 30, the nonaqueous electrolyte can simultaneously have high thermal stability, high conductivity and a wide electrochemical window, and the nonaqueous electrolyte can also passivate an aluminum foil current collector and form a dense, stable and low-impedance boundary film on the surface of a negative electrode active material, thereby allowing good cycle performance, storage performance, box safety performance and thermal film kinetics to be simultaneously considered. In any embodiment of the present application, the ratio of the mass content A1 of lithium difluorosulfimide in the nonaqueous electrolytic solution