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CN-122025823-A - Battery, preparation method thereof and electric device comprising battery

CN122025823ACN 122025823 ACN122025823 ACN 122025823ACN-122025823-A

Abstract

The application provides a battery, a preparation method thereof and an electric device comprising the same, wherein the battery comprises a positive electrode plate and electrolyte, the positive electrode plate comprises a positive electrode current collector, the positive electrode current collector comprises a conductive layer, the electrolyte comprises a first anion and a second anion, the first anion comprises one or more anions selected from hexafluorophosphate anions shown in a formula 1 and anions shown in a formula 2, the thickness of the conductive layer is H 1 mu m, the concentration of the first anion in the electrolyte is C 1 mol/L, the concentration of the second anion is C 2 mol/L, and the battery meets 0.2X (C 2 /C 1 )≤H 1 ≤(C 2 /C 1 ) +3. The application can improve the safety performance of the battery and simultaneously ensure that the battery has good electrochemical performance. 1 (1) 2, 2

Inventors

  • ZHANG CUIPING
  • HAN CHANGLONG
  • FAN PENG
  • ZHANG ZHE

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20220930

Claims (20)

  1. 1. A battery comprises a positive electrode plate and electrolyte, wherein, The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector, the positive electrode current collector comprises a conductive layer, The electrolyte includes a solvent and a solute, the solute is an ionic salt formed from cations and anions, the cations include one or more selected from alkali metal cations and alkaline earth metal cations, optionally include one or more selected from lithium ions, sodium ions and potassium ions, the anions include a first anion and a second anion, the first anion includes one or more selected from hexafluorophosphate anions, the second anion includes one or more selected from anions shown in formula 1 and anions shown in formula 2, R 1 、R 2 、R 3 each independently represents a fluorine atom or a C1-C5 fluorine-containing alkyl group, R 1 、R 2 may also bond to a ring, 1 (1) 2, 2 The thickness of the conductive layer is H 1 μm,0.2≤H 1 -8, the concentration of the first anions in the electrolyte is C 1 mol/L, and the concentration of the second anions in the electrolyte is C 2 mol/L,0.1≤C 1 ≤1,0.1≤C 2 -1.5.
  2. 2. The battery of claim 1, wherein 3≤h 1 ≤4,0.1≤C 1 ≤0.5,0.5≤C 2 ≤1.5; or 2.5≤H 4,0.1 is less than or equal to 1 and less than or equal to C1-0.5, 0.5-1.2 and C2.
  3. 3. The battery according to claim 1 or 2, wherein, H 1 is more than or equal to 1 and less than or equal to 5; and/or the number of the groups of groups, 0.5≤C 2 ≤1.5。
  4. 4. The battery according to any one of claim 1 to 3, wherein, 0.6C 1 +C 2 C2.5, alternatively, C 1 +C 2 is more than or equal to 0.6 and less than or equal to 2.0; and/or the number of the groups of groups, 0.1C 2 /C 1 C5, alternatively, C 2 /C 1 is more than or equal to 0.5 and less than or equal to 5.
  5. 5. The battery according to any one of claims 1-4, wherein the positive electrode current collector further comprises an organic support layer, the conductive layer is provided on at least one surface of the organic support layer, and the conductive layer is further provided between the organic support layer and the positive electrode active material layer.
  6. 6. The battery of claim 5, wherein the thickness of the organic support layer is H 2 μιη and the battery meets 0.1-H 1 /H 2 -1, optionally 0.2-H 1 /H 2 -0.6.
  7. 7. The battery of claim 5 or 6, wherein the thickness of the organic support layer is H 2 μm,1≤H 2 -10, optionally 4-H 2 -7.
  8. 8. The battery of any of claims 5-7, wherein the total thickness of the positive current collector is H 0 μm,5≤H 0 -15, optionally 9-H 0 -15.
  9. 9. The battery according to any one of claims 5-8, wherein the total thickness of the positive electrode current collector is H 0 μm, the elongation at break of the positive electrode current collector is S 0 , and the battery satisfies 5S 0 – (H 0 /10)≤C 1 /C 2 ≤100S 0 + (H 0 /9).
  10. 10. The battery of claim 9, wherein 2% to 3.5% S 0 %.
  11. 11. The battery of any of claims 5-10, wherein the organic support layer comprises one or more of a polymeric material and a polymeric matrix composite material, The polymer material comprises one or more selected from polyolefin, polyacetylene, polyester, polycarbonate, polyacrylate, polyamide, polyimide, polyether, polyalcohol, polysulfone, polysulfide, polysaccharide polymer, amino acid polymer, aromatic ring polymer, aromatic heterocyclic polymer, epoxy resin, phenolic resin, polyurethane, thermoplastic elastomer, rubber, derivative of the above material, cross-linked product of the above material and copolymer of the above material, and optionally comprises one or more selected from polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyacetylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, polycaprolactam, polyhexamethylene adipamide, poly (p-phenylene terephthalamide), polyoxymethylene, polyphenylene oxide, polyphenylene sulfide, polyethylene glycol, polyvinyl alcohol, poly (4) Hydroxybenzoic acid, poly 2 Hydroxy group 6 Naphthoic acid, polyaniline, polypyrrole, polythiophene, polyphenyl, sodium polystyrene sulfonate, cellulose, starch, silicone rubber and acrylonitrile Butadiene One or more of a styrene copolymer, a derivative of the above material, a crosslinked product of the above material, a copolymer of the above material, The polymer-based composite material comprises the polymer material and an additive, wherein the additive comprises one or more selected from a metal material and an inorganic nonmetallic material.
  12. 12. The battery of any of claims 1-11, wherein the conductive layer comprises one or more selected from a metallic material, optionally one or more selected from aluminum, silver, nickel, titanium, stainless steel, aluminum alloy, silver alloy, nickel alloy, and titanium alloy.
  13. 13. The battery of any of claims 1-12, wherein, R 1 、R 2 、R 3 independently represents a fluorine atom, trifluoromethyl, pentafluoroethyl or heptafluoropropyl group, and/or, R 1 and R 2 are identical.
  14. 14. The battery of any of claims 1-13, wherein the electrolyte further comprises a third anion comprising one or more selected from tetrafluoroborate anions, difluoroborate anions, dioxaborate anions, difluorophosphate anions, difluorodioxaphosphate anions, and tetrafluorooxalate phosphate anions.
  15. 15. The battery of any of claims 1-14, wherein the battery further comprises a negative electrode tab and a separator film, the separator film being located between the positive electrode tab and the negative electrode tab.
  16. 16. A method of making a battery comprising the steps of: step 1, assembling a positive pole piece, a separation film, a negative pole piece and electrolyte into a battery, The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector, the positive electrode current collector comprises a conductive layer, The electrolyte includes a solvent and a solute, the solute is an ionic salt formed from cations and anions, the cations include one or more selected from alkali metal cations and alkaline earth metal cations, optionally include one or more selected from lithium ions, sodium ions and potassium ions, the anions include a first anion and a second anion, the first anion includes one or more selected from hexafluorophosphate anions, the second anion includes one or more selected from anions shown in formula 1 and anions shown in formula 2, R 1 、R 2 、R 3 each independently represents a fluorine atom or a C1-C5 fluorine-containing alkyl group, R 1 、R 2 may also bond to a ring, 1 (1) 2, 2 The thickness of the conductive layer is H 1 mu m, the concentration of the first anions in the electrolyte is C 1 mol/L, and the concentration of the second anions in the electrolyte is C 2 mol/L; And 2, screening out the batteries which meet H 1 ≤8,0.1≤C 1 ≤1,0.1≤C 2 which is more than or equal to 0.2 and less than or equal to 1.5, optionally meet H 1 ≤4,0.1≤C 1 ≤0.5,0.5≤C 2 which is more than or equal to 3 and less than or equal to 1.5, or optionally meet H1 which is more than or equal to 2.5 and less than or equal to 4,0.1 and C1 which is more than or equal to 0.5 and C2 which is more than or equal to 0.5 and less than or equal to 1.2 from the batteries obtained in the step 1.
  17. 17. The method according to claim 16, wherein the method further comprises a step 3 of screening the cells obtained in the step 2 for cells satisfying at least one of the following conditions, (2)1≤H 1 ≤5, (5)0.5≤C 2 ≤1.5, (6)0.6≤C 1 +C 2 ≤2.5, (7)0.6≤C 1 +C 2 ≤2.0, (8)0.1≤C 2 /C 1 ≤5, (9)0.5≤C 2 /C 1 ≤5。
  18. 18. The method according to claim 16 or 17, wherein in step 1, the positive electrode current collector further comprises an organic support layer, the conductive layer is provided on at least one surface of the organic support layer, and the conductive layer is further provided between the organic support layer and the positive electrode active material layer, the thickness of the organic support layer is H 2 μm, the total thickness of the positive electrode current collector is H 0 μm, and the breaking elongation of the positive electrode current collector is S 0 .
  19. 19. The method according to claim 18, wherein the method further comprises a step 4 of screening out the cells obtained in the step 2 or the step 3 for cells satisfying at least one of the following conditions (1) to (8), (1)5S 0 – (H 0 /10)≤C 1 /C 2 ≤100S 0 + (H 0 /9), (2)0.1≤H 1 /H 2 ≤1, (3)0.2≤H 1 /H 2 ≤0.6, (4)1≤H 2 ≤10, (5)4≤H 2 ≤7, (6)5≤H 0 ≤15, (7)9≤H 0 ≤15, (8)2%≤S 0 ≤3.5%。
  20. 20. An electrical device comprising the battery of any one of claims 1-15 or a battery made by the method of any one of claims 16-19.

Description

Battery, preparation method thereof and electric device comprising battery The application relates to a battery, a preparation method thereof and an electric device comprising the battery, which are classified application of China patent application with the application number 202280015918.6, wherein the application date is 2022, 9 and 30. Technical Field The application belongs to the technical field of batteries, and particularly relates to a battery, a preparation method thereof and an electric device comprising the battery. Background In recent years, 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 batteries, the safety problem of the batteries is more and more concerned, and if the safety problem of the batteries cannot be guaranteed, the batteries cannot be used. Therefore, how to enhance the safety performance of the battery without affecting the electrochemical performance of the battery is a technical problem to be solved at present. Disclosure of Invention The application aims to provide a battery, a preparation method thereof and an electric device comprising the battery, which can reduce the influence of corrosion of a positive current collector on the safety performance and the electrochemical performance of the battery, thereby improving the safety performance of the battery and simultaneously ensuring the battery to have good electrochemical performance. The first aspect of the present application provides a battery comprising a positive electrode sheet and an electrolyte, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector, the positive electrode current collector comprises a conductive layer, the electrolyte comprises a solvent and a solute, the solute is an ionic salt formed by a cation and an anion, the cation comprises one or more selected from alkali metal cations and alkaline earth metal cations, optionally comprises one or more selected from lithium ions, sodium ions and potassium ions, the anion comprises a first anion and a second anion, the first anion comprises one or more selected from hexafluorophosphate anions, the second anion comprises one or more selected from anions represented by formula 1 and anions represented by formula 2, R 1、R2、R3 independently represents a fluorine atom or a fluoroalkyl group of C1-C5, R 1、R2 can be bonded into a ring, the thickness of the conductive layer is H 1 μm, the concentration of the first anion in the electrolyte is 1 x 2, the concentration of the second anion is 1 x 2.37 x/C3, and the concentration of the first anion in the electrolyte is 35 x 2. 1 (1) 2, 2 The inventors of the present application have surprisingly found through a large number of experiments that by adjusting the relationship between the thickness H 1 μm of the conductive layer, the concentration C 1 mol/L of the first anion and the concentration C 2 mol/L of the second anion to satisfy 0.2× (C 2/C1)≤H1≤(C2/C1) +3, the effect of corrosion of the conductive layer on the safety performance and electrochemical performance of the battery can be reduced, thereby improving the safety performance of the battery while allowing the battery to have good electrochemical performance, for example, the battery can have a longer service life. In any embodiment of the present application, 0.2× (C 2/C1) + 0.2≤H1≤(C2/C1) +2. Thus, the influence of corrosion of the conductive layer on the safety performance and electrochemical performance of the battery can be further reduced. In any embodiment of the application, 0.2≤H 1≤8, optionally 1≤H 1≤5. Therefore, the safety performance of the battery is improved, and meanwhile, the battery has good electrochemical performance. In any embodiment of the application, 0.1≤C 1≤1. The first anions help to increase the ionic conductivity of the electrolyte, accelerate ion transport, and increase capacity of the battery. In any embodiment of the application, 0.1C 2 C1.5, alternatively 0.5C 2 C1.5. The second anions can improve the ion dissociation degree of the electrolyte, reduce the viscosity of the electrolyte and improve the ion conductivity of the electrolyte, and in addition, the second anions also have the characteristics of good high temperature resistance and difficult hydrolysis, so that the cycle performance of the battery can be improved. In any embodiment of the application, 0.6C 1+C2 2.5, alternatively 0.6C 1+C2 2.0. In any embodiment of the application, 0.1C 2/C1 5, alternatively 0.5C 2/C1 5. When the concentration of the first anions and the concentration of the second anions meet the requirement that