Binder composition, electrode mixture, electrode, non-aqueous electrolyte secondary battery, and production method of binder composition

Patent metadata

Field	Value
Publication number	US-2020235401-A1
Application number	US-201716306175-A
Country	US
Kind code	A1
Filing date	May 18, 2017
Priority date	Jul 6, 2016
Publication date	Jul 23, 2020
Grant date	—

Abstract

A binder composition that exhibits sufficient adhesion and that achieves the excellent dispersibility of a conductive additive is provided. The binder composition according to an embodiment of the present invention is a binder composition including a vinylidene fluoride copolymer composition containing vinylidene fluoride and a monomer having an acidic functional group; and a ratio (Mn2/Mn1) of a number average molecular weight of the vinylidene fluoride copolymer composition after being adsorbed onto alumina (Mn2) to a number average molecular weight of the vinylidene fluoride copolymer composition before being adsorbed onto alumina (Mn1) being less than 1.

First claim

1 . A binder composition for binding an electrode active material to a current collector,
the binder composition comprising a vinylidene fluoride copolymer composition; and the vinylidene fluoride copolymer composition comprising a copolymer of vinylidene fluoride and a monomer having an acidic functional group; wherein the vinylidene fluoride copolymer composition has, in a case where the vinylidene fluoride copolymer composition is adsorbed onto alumina, a ratio (Mn2/Mn1) of less than 1, the ratio of a number average molecular weight of the vinylidene fluoride copolymer composition that is not adsorbed onto the alumina after the adsorption (Mn2) to a number average molecular weight of the vinylidene fluoride copolymer composition before the adsorption (Mn1).

2 . The binder composition according to claim 1 , wherein the acidic functional group is a carboxy group.

3 . The binder composition according to claim 1 , wherein the monomer having an acidic functional group is a compound represented by Formula (1) below:

wherein, R 1 , R 2 , and R 3 are each independently a hydrogen atom, a fluorine atom, a chlorine atom, or an alkyl group having from 1 to 3 carbons, and X is an atomic group having a main chain formed from 1 to 10 atoms and having a molecular weight of 500 or less and includes at least one heteroatom selected from the group consisting of an oxygen atom and a nitrogen atom.

4 . The binder composition according to claim 1 , wherein the monomer having an acidic functional group is at least one type selected from the group consisting of 2-carboxyethyl acrylate, acryloyloxyethyl succinate, and acryloyloxypropyl succinate.

5 . An electrode mixture comprising: the binder composition described in claim 1 , an electrode active material, and a conductive additive.

6 . An electrode comprising a layer formed from the electrode mixture described in claim 5 on a current collector.

7 . A non-aqueous electrolyte secondary battery comprising the electrode described in claim 6 .

8 . A method of producing a binder composition, the binder composition for binding an electrode active material to a current collector,
the method comprising: performing polymerization including subjecting vinylidene fluoride and a monomer having an acidic functional group to copolymerization to produce a vinylidene fluoride copolymer composition, wherein, in the performing polymerization, the addition of the monomer having an acidic functional group is completed before a polymerization yield of the vinylidene fluoride copolymer composition exceeds 90%.

Assignees

• Kureha Corp

Inventors

• Sakai Yuki
• Kamata Shintarou
• Sugawara Emi

Classifications

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/0404 Primary

  by coating on electrode collectors · CPC title

• H01M10/052

  Li-accumulators · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• C08F214/225

  with non-fluorinated comonomers · CPC title