Binder composition, secondary battery, battery module, battery pack and power consuming device
Provided are a binder composition, an electrode, a battery and a power consuming device. The binder composition comprises a fluoropolymer A and a copolymer B, wherein the copolymer B comprises a structural unit derived from a monomer containing a cyano group and a structural unit derived from a monomer containing an ester group. The binder of the present application has a strong bonding force, and the cycling performance of the secondary battery comprising same is excellent.
1 . A binder composition, comprising a fluoropolymer A and a copolymer B, wherein the copolymer B comprises a structural unit derived from a monomer containing a cyano group and a structural unit derived from a monomer containing an ester group, a mass ratio of the structural unit derived from the monomer containing the cyano group to the structural unit derived from the monomer containing the ester group in the copolymer B is 8:1 to 12:1, based on a total mass of the copolymer B,
wherein the copolymer B further comprises a structural unit derived from the monomer containing the group shown in formula I,
in which, n is selected from 0, 1, 2, or 3, and
wherein a mass content of the structural unit derived from the monomer containing a group shown in formula I is 0.1%-1.5%, based on a total mass of the copolymer B,
wherein the monomer containing the cyano group is acrylonitrile, the monomer containing the ester group is isooctyl acrylate, the monomer containing the group shown in formula I is N-allyl-2-pyrrolidone.
2 . The binder composition according to claim 1 , wherein a weight average molecular weight of the fluoropolymer A is 600,000-900,000 g/mol, and a weight average molecular weight of the copolymer B is 400,000-700,000 g/mol.
3 . The binder composition according to claim 1 , wherein a mass ratio of the fluoropolymer A to the copolymer Bis 1:4-4:1.
4 . The binder composition according to claim 1 , wherein the fluoropolymer A is selected from one or more of polyvinylidene fluoride, and the copolymers thereof with tetrafluoroethylene, hexafluoropropylene, and trichloroethylene.
5 . The binder composition according to claim 1 , wherein the monomer containing the cyano group is selected from one or more of acrylonitrile, methacrylonitrile, halogenated acrylonitrile, and methoxyacrylonitrile.
6 . The binder composition according to claim 1 , wherein the monomer containing the ester group is selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isoamyl acrylate, isooctyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate.
7 . The binder composition according to claim 1 , wherein the mass ratio of the structural unit derived from the monomer containing the cyano group to the structural unit derived from the monomer containing the ester group in the copolymer B is 8:1-10:1.
8 . The binder composition according to claim 7 , wherein the monomer containing the group shown in formula I is selected from one or more of N-vinylpyrrolidone and N-allyl-2-pyrrolidone.
9 . The binder composition according to claim 1 , wherein the mass content of the structural unit derived from the monomer containing the group shown in formula I is 0.5%-1.0%, based on the total mass of the copolymer B.
10 . The binder composition of claim 1 , wherein, based on a total mass of the copolymer B, a mass content of the structural unit derived from the monomer containing the cyano group is from 80% to 95%, a mass content of the structural unit derived from the monomer containing the ester group is from 8% to 12%, a mass content of the structural unit derived from the monomer containing the group shown in formula I is from 0.5% to 1.5%.
11 . The binder composition of claim 1 , wherein the fluoropolymer A is polyvinylidene fluoride (PVDF) having a particle size Dv50 of 5 μm to 10 μm, a crystallinity of 35-40%, and a melting point from 160° C. to 170° C.
12 . A secondary battery, comprising an electrode assembly and an electrolyte solution, wherein the electrode assembly includes a positive electrode plate, a separator and a negative electrode plate, and the positive electrode plate comprises a positive electrode active material and the binder according to claim 1 .
13 . The secondary battery according to claim 12 , wherein the positive electrode active material is a lithium-containing transition metal oxide, a doped and modified material of the lithium-containing transition metal oxide, a conductive carbon-coated modified material of the lithium-containing transition metal oxide, a conductive metal-coated modified material of the lithium-containing transition metal oxide, or a conductive polymer-coated modified material of the lithium-containing transition metal oxide.
14 . A battery module, comprising the secondary battery according to claim 12 .
15 . A battery pack, comprising the battery module according to claim 14 .
16 . A power consuming device, comprising the secondary battery according to claim 12 .
17 . A power consuming device, comprising the battery module according to claim 14 .