BINDER FOR SECONDARY BATTERIES AND PREPARATION METHOD, SECONDARY BATTERY, AND ELECTRICAL APPARATUS THEREOF
The present application relates to the technical field of secondary batteries, and in particular to a binder for secondary batteries and a preparation method, a secondary battery, and an electrical apparatus thereof. The binder includes a core structure and a shell structure disposed on a surface of the core structure. The shell structure includes an acrylate copolymer, and the core structure comprises a rigid polymer. The rigid polymer has a crystallinity ranging from 32% to 94%. The binder with a core-shell structure includes the core structure of the rigid polymer. During cold pressing of a battery cell, the rigid polymer acts as a support, making a particle structure of the binder stable, that is, the rigid polymer acts as a support, resulting in an overall increase in the rigidity of the binder.
1 . A binder for secondary batteries, wherein the binder comprises a core structure and a shell structure disposed on a surface of the core structure, the shell structure comprises an acrylate copolymer, the core structure comprises a rigid polymer, and the rigid polymer has a crystallinity ranging from 32% to 94%.
2 . The binder for secondary batteries according to claim 1 , wherein the rigid polymer has a crystallinity ranging from 40% to 80%.
3 . The binder for secondary batteries according to claim 1 , wherein the rigid polymer comprises at least one of polyethylene, polypropylene, polystyrene, polymethyl methacrylate, and polyamide.
4 . The binder for secondary batteries according to claim 1 , wherein the shape of the binder comprises a spherical shape.
5 . The binder for secondary batteries according to claim 1 , wherein the binder has a volume particle size distribution Dv50 of 1 μm to 15 μm, and preferably, the binder has a volume particle size distribution Dv50 of 1 μm to 12 μm.
6 . The binder for secondary batteries according to claim 1 , wherein a ratio of a volume particle size distribution Dv50 of the acrylate copolymer to a volume particle size distribution Dv50 of the rigid polymer is 1:(1-50).
7 . The binder for secondary batteries according to claim 6 , wherein the rigid polymer has a volume particle size distribution Dv50 of 0.1 μm to 5 μm, and preferably, the rigid polymer has a volume particle size distribution Dv50 of 0.5 μm to 2 μm;
and/or, the acrylate copolymer has a volume particle size distribution Dv50 of 100 nm to 200 nm, and preferably, the acrylate copolymer has a volume particle size distribution Dv50 of 130 nm to 180 nm.
8 . The binder for secondary batteries according to claim 1 , wherein a ratio of mass of the shell structure to mass of the core structure is 1:(0.1-10), and preferably, a ratio of mass of the shell structure to mass of the core structure is 1:(0.1-5).
9 . The binder for secondary batteries according to claim 1 , wherein the acrylate copolymer comprises at least two of an acrylate monomer, an acrylonitrile monomer and an acrylamide monomer as constituent monomers.
10 . The binder for secondary batteries according to claim 9 , wherein the acrylate monomer comprises at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate;
and/or, the acrylonitrile monomer comprises at least one of acrylonitrile or methacrylonitrile;
and/or, the acrylamide monomer comprises at least one of acrylamide, N-hydroxymethylacrylamide and N-butoxymethylacrylamide.
11 . The binder for secondary batteries according to claim 1 , wherein the acrylate copolymer comprises an acrylate monomer, an acrylonitrile monomer and an acrylamide monomer as constituent monomers, the acrylate monomer, the acrylonitrile monomer and the acrylamide monomer have a mass ratio of 1:(0.01-0.8):(0.01-0.15), and preferably, the acrylate monomer, the acrylonitrile monomer and the acrylamide monomer have a mass ratio of 1:(0.1-0.6):(0.06-0.12).
12 . A preparation method of a binder for secondary batteries according to claim 1 , comprising:
preparing an acrylate copolymer emulsion; and
blending the acrylate copolymer emulsion with a rigid polymer and performing spray drying to obtain a binder with a core-shell structure.
13 . The preparation method of a binder for secondary batteries according to claim 12 , wherein the step of preparing an acrylate copolymer emulsion comprises:
stirring and emulsifying water, an emulsifier and constituent monomers of the acrylate copolymer to obtain a pre-emulsion of monomers; and
stirring the emulsifier and the water to emulsify, adding the pre-emulsion and an initiator under a heating condition, and raising the temperature to obtain the acrylate copolymer emulsion.
14 . A separator, wherein the separator comprises a base film and a binder layer disposed on at least one side of the base film, the binder layer comprises the binder for secondary batteries according to claim 1 .
15 . A separator, wherein the binder layer comprises a binder prepared by the preparation method of a binder for secondary batteries according to claim 12 .
16 . A secondary battery, comprising the separator according to claim 14 .
17 . An electrical apparatus, comprising the secondary battery according to claim 16 .