CN-122003735-A - Positive electrode active material, positive electrode plate, cylindrical battery cell, battery and electricity utilization device

Abstract

The application relates to a positive electrode active material, a positive electrode plate, a cylindrical battery cell, a battery and an electric device, wherein the positive electrode active material comprises a core part and a coating layer, the core part comprises lithium-containing transition metal oxide, the coating layer is coated on at least part of the surface of the core part, the coating layer comprises a polymer, and the polymer comprises one or more of fluorine-containing polymer and oxygen-containing polymer. When the positive electrode active material is applied to a battery, the expansion degree of the battery can be reduced, and the cycle performance of the battery can be improved.

Inventors

• CHEN QIANG
• WU QI
• ZHANG QIYU
• JIAO WEN
• Fan Jingpeng
• DONG HANYUAN
• LIU NA

Assignees

• 宁德时代新能源科技股份有限公司

Dates

Publication Date

20260508

Application Date

20250116

Priority Date

20240422

Claims (20)

1. A positive electrode active material comprising a core portion comprising a lithium-containing transition metal oxide and a coating layer coating at least a portion of a surface of the core portion, the coating layer comprising a polymer comprising one or more of a fluoropolymer and an oxygen-containing polymer.
2. The positive electrode active material according to claim 1, wherein the fluorine-containing polymer comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, and tetrafluoroethylene-hexafluoropropylene copolymer.
3. The positive electrode active material according to claim 1 or 2, wherein the oxygen-containing polymer comprises one or more of an ether polymer and an ester polymer.
4. The positive electrode active material according to claim 3, wherein the ether polymer comprises one or more of polyethylene glycol and polypropylene glycol, and/or The ester polymer includes one or more of polyvinyl acetate and polymethyl methacrylate.
5. The positive electrode active material according to any one of claims 1 to 4, wherein a mass content of the polymer in the positive electrode active material is 0.15% to 1.0%.
6. The positive electrode active material according to claim 5, wherein the mass content of the polymer in the positive electrode active material is 0.15% to 0.7%.
7. The positive electrode active material according to any one of claims 1 to 6, wherein the coating layer further comprises a fast ion conductor.
8. The positive electrode active material according to claim 7, wherein the mass content of the fast ion conductor in the positive electrode active material is 0.5% to 2.5%.
9. The positive electrode active material according to claim 8, wherein the mass content of the fast ion conductor in the positive electrode active material is 0.5% to 2.0%.
10. The positive electrode active material according to any one of claims 7 to 9, wherein the coating layer includes: a first layer coated on the surface of the core part and comprising the fast ion conductor, and And a second layer disposed on a side of the first layer facing away from the core, the second layer comprising the polymer.
11. The positive electrode active material of any one of claims 1 to 10, wherein the lithium-containing transition metal oxide comprises a compound of the general formula Li x A y Ni a Co b Mn c M (1-a-b-c) Q z , wherein 0< x+≤ 2.1,0 +≤y+≤2.1, and 0.9+≤x+y+≤2.1, 0< a <1,0< b <1, 0+.c <1, and 0.1+≤a+b+c≤1, 1.8+.z≤3.5, a includes one or more of Na, K, mg, M includes one or more of B, mg, al, si, P, S, ca, sc, ti, V, cr, fe, cu, zn, sr, Y, zr, nb, mo, cd, sn, sb, te, ba, ta, W, yb, la, ce, se, Q includes one or more of O, F.
12. The positive electrode active material according to claim 11, wherein 0.6≤a≤1.
13. The positive electrode active material according to any one of claims 1 to 12, wherein a volume average particle size D v to 15 μm of the positive electrode active material.
14. The positive electrode active material according to claim 13, wherein the positive electrode active material has a volume average particle size D v of 7 μm to 12 μm.
15. A positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer provided on at least one side of the positive electrode current collector, the positive electrode film layer comprising the positive electrode active material according to any one of claims 1 to 14.
16. The positive electrode sheet of claim 15, wherein the positive electrode film layer further comprises a positive electrode binder comprising one or more of a fluoropolymer and an acrylate resin.
17. The positive electrode sheet according to claim 16, wherein the fluoropolymer comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and/or The acrylic resin comprises one or more of poly (methyl fluoroacrylate) and polyacrylate.
18. A cylindrical battery cell comprising the positive electrode tab of any one of claims 15 to 17.
19. The cylindrical battery cell of claim 18, wherein the positive electrode sheet has a full charge expansion rate of 6% or less.
20. The cylindrical battery cell according to claim 19, wherein the positive electrode tab has a full charge expansion ratio of 4.9% or less.

Description

Positive electrode active material, positive electrode plate, cylindrical battery cell, battery and electricity utilization device Cross Reference to Related Applications The present application claims priority from chinese patent application 202410486790.2 entitled "positive active material, positive electrode tab, cylindrical battery cell, battery and power device" filed on 22 nd 04 th year 2024, the entire contents of which are incorporated herein by reference. Technical Field The application relates to a positive electrode active material, a positive electrode plate, a cylindrical battery cell, a battery and an electric device. Background The battery has high capacity and other characteristics, and thus is widely used in electronic devices such as mobile phones, notebook computers, battery cars, electric vehicles, electric airplanes, electric ships, electric toy vehicles, electric toy ships, electric toy airplanes, electric tools, and the like. The battery includes a positive electrode tab, which is continuously expanded during the charging process, so that the degree of expansion of the battery is high, and the cycle performance of the battery may be deteriorated. Disclosure of Invention The application provides a positive electrode active material, a positive electrode plate, a cylindrical battery monomer, a battery and an electric device, when the positive electrode active material is applied to a battery, the expansion degree of the battery can be reduced, and the cycle performance of the battery can be improved. In a first aspect, embodiments of the present application provide a positive electrode active material, the positive electrode active material including a core portion including a lithium-containing transition metal oxide, and a coating layer coating at least a portion of a surface of the core portion, the coating layer including a polymer including one or more of a fluoropolymer and an oxygen-containing polymer. The lithium-containing transition metal oxide has relatively high theoretical specific capacity, can effectively improve the energy density of the battery, is provided with a coating layer on the surface of the core part, can cover part of the surface of the core part and can also cover all the surface of the core part, the coating layer comprises a polymer, the polymer can comprise one or more of fluorine-containing polymers and oxygen-containing polymers, and can effectively connect an anode active material and an auxiliary agent such as a binder in the anode plate, so that the auxiliary agent can synchronously change along with the volume change of the anode active material, especially synchronously shrink when the anode active material shrinks, thereby effectively reducing the volume expansion of the whole anode plate, reducing the full charge expansion degree of a battery monomer and improving the cycle performance of the battery monomer. In some embodiments, the fluoropolymer comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, and tetrafluoroethylene-hexafluoropropylene copolymer. The fluorine-containing polymer and the positive electrode active material have strong binding force, can be effectively bonded with a binder and the like in the positive electrode film layer, and strengthen the binding force between the parts to form common-frequency shrinkage expansion, so that the auxiliary agent in the positive electrode film layer is easier to synchronously change along with the volume change of the positive electrode active material. In some embodiments, the oxygen-containing polymer includes one or more of an ether polymer and an ester polymer. The oxygen-containing polymer has excellent flexibility, so that the flexibility of the positive electrode film layer is improved, the extensibility is improved, and the oxygen-containing polymer can react with a binder in the positive electrode film layer to reduce crystallinity, so that the whole positive electrode film layer can deform along with the volume change of a positive electrode active material, and the problems of expansion and interface contact of components caused by the volume change are reduced. In some embodiments, the ether-based polymer includes one or more of polyethylene glycol and polypropylene glycol. In some embodiments, the ester polymer comprises one or more of polyvinyl acetate and polymethyl methacrylate. In some embodiments, the mass content of the polymer in the positive electrode active material is 0.15% to 1.0%. When the mass content of the polymer is in the range, the core part can be effectively coated, so that the anode active material, the binder and the like can realize the same-frequency shrinkage and expansion, the overall expansion rate of the anode film layer is reduced, the expansion degree of the battery monomer is reduced, and the cycle