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CN-122025831-A - Secondary battery, method for manufacturing the same, and power consumption device

CN122025831ACN 122025831 ACN122025831 ACN 122025831ACN-122025831-A

Abstract

The application provides a secondary battery, an electric device and a preparation method of the secondary battery. The secondary battery comprises a positive electrode plate, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material and an additive, the additive comprises blocked isocyanate, and blocked molecules used for blocking comprise one or more of compounds with a structure shown in the following formula I. The isocyanate includes one or more of the compounds having the structure of formula II below. The secondary battery uses the blocked isocyanate as an additive to be contained in a positive electrode film layer, wherein unsaturated bonds can react with oxygen radicals generated by a positive electrode active material to generate stable compounds, so that the secondary battery generates gas. R 2 -[OH] n (I) R 3 -[NCO] m (II).

Inventors

  • GUO YUHUA
  • LIU YIXIU
  • ZHENG YI
  • Di Shenghan
  • LI XINYU

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (20)

  1. 1. The secondary battery is characterized by comprising a positive electrode plate, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material and an additive, the additive comprises blocked isocyanate, and a blocking molecule used for blocking comprises one or more of compounds with the structure shown in the following formula I: R 2 -[OH] n (I) The isocyanate includes one or more of the compounds having the structure of formula II: R 3 -[NCO] m (II) Wherein, in the above formula I and formula II, when n=1, m is any integer from 1 to 3, or when m=1, n is any integer from 1 to 3; R 2 comprises one of substituted or unsubstituted monovalent to trivalent C 3-10 alkenyl, substituted or unsubstituted monovalent to trivalent C 3-10 alkynyl, substituted or unsubstituted monovalent to trivalent C 2-10 cyano, and-R 4 -NHC(＝O)-R 5 , wherein R 4 and R 5 each independently comprise one of substituted or unsubstituted C 1-10 alkyl and substituted or unsubstituted C 2-10 alkenyl, and at least one of R 4 and R 5 is alkenyl; R 3 comprises one of monovalent to trivalent R 1 and R 6 -[OC(＝O)NH-R 1 ] p -, wherein, R 1 includes substituted or unsubstituted monovalent to trivalent C 1-10 alkyl and substituted or unsubstituted monovalent to trivalent C 3-20 alkyl containing a three to six membered ring, R 6 comprises a substituted or unsubstituted monovalent to trivalent C 1-10 alkyl group, p=m, Wherein the substitution is by one OR more substituents selected from the group consisting of halogen, -N (=o) 2 OR c 、-S(＝O) 2 OR c 、-P(＝O) 2 OR c and-NHC (=o) OR c , wherein each R c is independently selected from the group consisting of alkali metal ions and C 1-4 alkyl.
  2. 2. The secondary battery of claim 1, wherein R 2 comprises one of a substituted or unsubstituted monovalent to trivalent C 3-6 alkenyl group, a substituted or unsubstituted monovalent to trivalent C 3-6 alkynyl group, a substituted or unsubstituted monovalent to trivalent C 2-6 cyano group, and-R 4 -NHC(＝O)-R 5 , wherein R 4 and R 5 each independently comprise one of a substituted or unsubstituted C 1-4 alkyl group and a substituted or unsubstituted C 2-4 alkenyl group.
  3. 3. The secondary battery according to claim 1 or 2, wherein R 1 comprises a substituted or unsubstituted monovalent to trivalent C 2-8 alkyl group and a substituted or unsubstituted monovalent to trivalent C 5-18 alkyl group containing a five or six membered ring, and R 6 comprises a substituted or unsubstituted monovalent to trivalent C 1-6 alkyl group.
  4. 4. A secondary battery according to any one of claims 1-3, wherein the substitution is R 2 OR R 3 , optionally R 2 OR R 6 , substituted with one OR more groups selected from-S (=o) 2 OR c 、F-、-P(＝O) 2 OR c 、-N(＝O) 2 OR c and-NHC (=o) OR c , wherein each R c is independently selected from methyl and ethyl.
  5. 5. The secondary battery according to any one of claims 1 to 4, wherein n=1, m=2 or 3; Alternatively, R 2 comprises one of substituted or unsubstituted C 3-6 alkenyl, substituted or unsubstituted C 3-6 alkynyl, substituted or unsubstituted C 2-6 cyano, and-R 4 -NHC(＝O)-R 5 , wherein R 4 and R 5 each independently comprises one of substituted or unsubstituted C 1-4 alkyl and substituted or unsubstituted C 2-4 alkenyl; R 3 includes substituted or unsubstituted C 1-6 alkylene and C 5-10 divalent alkyl groups containing a three to six membered ring.
  6. 6. The secondary battery according to claim 5, wherein, The isocyanate comprises one or more of isophorone diisocyanate, hexamethylene diisocyanate and hexamethylene diisocyanate trimer; the end capping molecule comprises one or more of N-hydroxyethyl acrylamide, N-hydroxypropyl acrylamide, N-hydroxyethyl methacrylamide, 3-hydroxypropyl cyanide and 3-hydroxybutane cyanide.
  7. 7. The secondary battery according to any one of claims 1 to 5, wherein the blocked isocyanate has a molecular weight of 1,000 or less, optionally 800 or less, more optionally 600 or less.
  8. 8. The secondary battery according to any one of claims 1 to 7, wherein the blocked isocyanate is obtained by reacting the isocyanate and the blocking molecule in a ratio of an isocyanate index R of 1.0 to 1.2, optionally 1.05 to 1.1, and optionally the reaction system after the end of the reaction is directly used as the additive.
  9. 9. The secondary battery according to any one of claims 1 to 8, wherein the additive is contained in an amount of 0.2 to 1wt%, optionally 0.3 to 0.8wt%, more optionally 0.4 to 0.6wt%, based on the total weight of the positive electrode film layer.
  10. 10. The secondary battery according to any one of claims 1 to 9, wherein the positive electrode active material comprises LiNi 10-x-y Co x M y O 2 , wherein M comprises at least one of Al, Y, zr, la, ti, mg, nb, mn, W, sr, wherein 1< x <5,1< y <5, optionally M is Al or Mn.
  11. 11. An electric device comprising the secondary battery according to any one of claims 1 to 10.
  12. 12. A preparation method of a secondary battery is characterized in that the secondary battery comprises a positive electrode plate, the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material and an additive, the additive comprises blocked isocyanate, The preparation method comprises the following steps: adding the reaction product of isocyanate and blocking molecule as the additive to the positive electrode slurry, wherein, The capping molecules include one or more of the compounds having the structure of formula I: R 2 -[OH] n (I) The isocyanate includes one or more of the compounds having the structure of formula II: R 3 -[NCO] m (II) Wherein, in the above formula I and formula II, when n=1, m is any integer from 1 to 3, or when m=1, n is any integer from 1 to 3; R 2 comprises one of substituted or unsubstituted monovalent to trivalent C 3-10 alkenyl, substituted or unsubstituted monovalent to trivalent C 3-10 alkynyl, substituted or unsubstituted monovalent to trivalent C 3-10 cyano, and-R 4 -NHC(＝O)-R 5 , wherein R 4 and R 5 each independently comprise one of substituted or unsubstituted C 1-10 alkyl and substituted or unsubstituted C 2-10 alkenyl, and at least one of R 4 and R 5 is alkenyl; R 3 comprises one of monovalent to trivalent R 1 and R 6 -[OC(＝O)NH-R 1 ] p -, wherein, R 1 includes substituted or unsubstituted monovalent to trivalent C 1-10 alkyl and substituted or unsubstituted monovalent to trivalent C 3-20 alkyl containing a three to six membered ring, R 6 comprises a substituted or unsubstituted monovalent to trivalent C 1-10 alkyl group, p=m, The substitution is by one OR more substituents selected from the group consisting of halogen, -N (=o) 2 OR c 、-S(＝O) 2 OR c 、-P(＝O) 2 OR c and-NHC (=o) OR c , wherein each R c is independently selected from the group consisting of alkali metal ions and C 1-4 alkyl.
  13. 13. The method of claim 12, wherein R 2 comprises one of substituted or unsubstituted monovalent to trivalent C 3-6 alkenyl, substituted or unsubstituted monovalent to trivalent C 3-6 alkynyl, substituted or unsubstituted monovalent to trivalent C 3-6 cyano, and-R 4 -NHC(＝O)-R 5 , wherein R 4 and R 5 each independently comprises one of substituted or unsubstituted C 1-4 alkyl and substituted or unsubstituted C 2-4 alkenyl.
  14. 14. The method of claim 12 or 13, wherein R 1 comprises a substituted or unsubstituted monovalent to trivalent C 2-8 alkyl group and a substituted or unsubstituted monovalent to trivalent C 5-18 alkyl group containing a five or six membered ring; R 6 comprises a substituted or unsubstituted monovalent to trivalent C 1-6 alkyl group.
  15. 15. The method of any one of claims 12 to 14, wherein the substitution is R 2 OR R 3 , optionally R 2 OR R 6 , substituted with one OR more groups selected from-S (=o) 2 OR c 、F-、-P(＝O) 2 OR c 、-N(＝O) 2 OR c and-NHC (=o) OR c , wherein each R c is independently selected from methyl and ethyl.
  16. 16. The method of any one of claims 12-15, wherein n = 1, m = 2 or 3; alternatively, R 2 comprises one of substituted or unsubstituted C 3-6 alkenyl, substituted or unsubstituted C 3-6 alkynyl, substituted or unsubstituted C 3-6 cyano, and-R 4 -NHC(＝O)-R 5 , wherein R 4 and R 5 each independently comprises one of substituted or unsubstituted C 1-4 alkyl and substituted or unsubstituted C 2-4 alkenyl; R 3 includes substituted or unsubstituted C 1-6 alkylene and C 5-10 divalent alkyl groups containing a three to six membered ring.
  17. 17. The method of claim 16, wherein the process comprises, The isocyanate comprises one or more of isophorone diisocyanate, hexamethylene diisocyanate and hexamethylene diisocyanate trimer; the end capping molecule comprises one or more of N-hydroxyethyl acrylamide, N-hydroxypropyl acrylamide, N-hydroxyethyl methacrylamide, 3-hydroxypropyl cyanide and 3-hydroxybutane cyanide.
  18. 18. The method of any one of claims 12 to 16, wherein the blocked isocyanate has a molecular weight of 1,000 or less, optionally 800 or less, more optionally 600 or less.
  19. 19. The preparation method according to any of claims 12-18, characterized in that the isocyanate and the blocking molecule are reacted in a ratio of isocyanate index R of 1.0 to 1.2, optionally 10.5-1.10.
  20. 20. The method according to any one of claims 12 to 19, wherein the reaction product is obtained by reacting the isocyanate and the blocking molecule at 70 ℃ to 90 ℃, optionally adding the reaction product of isocyanate and blocking molecule as the additive to a positive electrode slurry comprises directly adding the reaction system after the end of the reaction to the positive electrode slurry.

Description

Secondary battery, method for manufacturing the same, and power consumption device Technical Field The application relates to the technical field of lithium ion secondary batteries, in particular to an additive for a positive electrode. Background In recent years, as the application range of the lithium ion secondary battery is wider and wider, the lithium ion secondary battery is widely applied to energy storage power supply systems such as hydraulic power, firepower, wind power, solar power stations and the like, and a plurality of fields such as electric tools, electric bicycles, electric motorcycles, electric automobiles, aerospace and the like. However, gas is generated during the circulation and storage of the battery, thereby affecting the life of the battery. Therefore, there is a need for improvement in view of the problem of gas production from batteries. Disclosure of Invention The present application has been made in view of the above problems, and an object of the present application is to provide a secondary battery with reduced gas production. In addition, the application also provides a preparation method of the secondary battery and an electric device comprising the secondary battery. In order to achieve the above object, a first aspect of the present application provides a secondary battery. The secondary battery comprises a positive electrode plate, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material and an additive, the additive comprises blocked isocyanate, and blocked molecules comprise one or more of compounds with the structure shown in the following formula I: R2-[OH]n(I) The isocyanate includes one or more of the compounds having the structure of formula II: R3-[NCO]m(II) Wherein, in the above formula I and formula II, when n=1, m is any integer from 1 to 3, or when m=1, n is any integer from 1 to 3; R 2 comprises one of substituted or unsubstituted monovalent to trivalent C 3-10 alkenyl, substituted or unsubstituted monovalent to trivalent C 3-10 alkynyl, substituted or unsubstituted monovalent to trivalent C 2-10 cyano, and-R 4-NHC(＝O)-R5, wherein R 4 and R 5 each independently comprise one of substituted or unsubstituted C 1-10 alkyl and substituted or unsubstituted C 2-10 alkenyl, and at least one of R 4 and R 5 is alkenyl; R 3 comprises one of monovalent to trivalent R 1 and R 6-[OC(＝O)NH-R1]p -, wherein, R 1 includes substituted or unsubstituted monovalent to trivalent C 1-10 alkyl and substituted or unsubstituted monovalent to trivalent C 3-20 alkyl containing a three to six membered ring, R 6 comprises a substituted or unsubstituted monovalent to trivalent C 1-10 alkyl group, p=m, Wherein the substitution is by one OR more substituents selected from the group consisting of halogen, -N (=o) 2ORc、-S(＝O)2ORc、-P(＝O)2ORc and-NHC (=o) OR c, wherein each R c is independently selected from the group consisting of alkali metal ions and C 1-4 alkyl. In the present disclosure, the blocked isocyanate is used as an additive to be contained in the positive electrode film layer, wherein the unsaturated bond can react with oxygen free radical generated by the positive electrode active material preferentially to generate a stable compound, so that the generation of gas due to side reaction of the oxygen free radical and components in the battery is reduced. In some embodiments, R 2 comprises one of substituted or unsubstituted monovalent to trivalent C 3-6 alkenyl, substituted or unsubstituted monovalent to trivalent C 3-6 alkynyl, substituted or unsubstituted monovalent to trivalent C 2-6 cyano, and-R 4-NHC(＝O)-R5, wherein R 4 and R 5 each independently comprise one of substituted or unsubstituted C 1-4 alkyl and substituted or unsubstituted C 2-4 alkenyl. In some embodiments, R 1 comprises a substituted or unsubstituted monovalent to trivalent C 2-8 alkyl group and a substituted or unsubstituted monovalent to trivalent C 5-18 alkyl group containing a five or six membered ring, and R 6 comprises a substituted or unsubstituted monovalent to trivalent C 1-6 alkyl group. The molecular weights of the optional blocking molecule and the isocyanate molecule are smaller, so that the number of unsaturated bonds is relatively larger at the same addition amount, which is more advantageous for reducing the gas production of the secondary battery. In addition, smaller blocked isocyanate molecules are more readily dispersed in the positive electrode slurry without causing excessive viscosity of the slurry. In some embodiments, the substitution is R 2 OR R 3, optionally R 2 OR R 6, substituted with one OR more groups selected from-S (=o) 2ORc、F-、-P(＝O)2ORc、-N(＝O)2ORc and-NHC (=o) OR c, wherein each R c is independently selected from methyl and ethyl. These functional substituents