Binder for lithium ion secondary battery electrode, production method for lithium ion secondary battery electrode, lithium ion secondary battery electrode, and lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-9647270-B2
Application number	US-201615058649-A
Country	US
Kind code	B2
Filing date	Mar 2, 2016
Priority date	Sep 6, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

The present invention provides a binder for a lithium ion secondary battery electrode that has good adhesive properties and a low degree of swelling with respect to an electrolytic solution. There is used a binder for a lithium ion secondary battery electrode, which comprises a polyvinyl acetal-based resin (A) containing structural units represented by chemical formulae (1) to (3):

(R1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms), and

(R2 is a functional group containing an ethylenically unsaturated bond).

First claim

The invention claimed is:

1. A binder for a lithium ion secondary battery electrode, which comprises a polyvinyl acetal-based resin (A) containing structural units represented by chemical formulae (1) to (3):

wherein R1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and

wherein R2 is a functional group containing an ethylenically unsaturated bond.

2. The binder for a lithium ion secondary battery electrode according to claim 1 , wherein, in the polyvinyl acetal-based resin (A), the degree of acetalization of the structural unit represented by the formula (2) is from 10 to 40% by mol.

3. The binder for a lithium ion secondary battery electrode according to claim 1 , wherein, in the polyvinyl acetal-based resin (A), the degree of crosslinking group modification of the structural unit represented by the formula (3) is from 0.1 to 15% by mol.

4. The binder for a lithium ion secondary battery electrode according to claim 1 , wherein, in the polyvinyl acetal-based resin (A), the content of the structural unit represented by the formula (1) is from 45 to 89.9% by mol.

5. The binder for a lithium ion secondary battery electrode according to claim 1 , wherein the average degree of polymerization of the polyvinyl acetal-based resin (A) is 1,500 or more.

6. The binder for a lithium ion secondary battery electrode according to claim 1 , which contains a solvent (B).

7. The binder for a lithium ion secondary battery electrode according to claim 1 , which contains a polymerization initiator (C).

8. A method for producing a lithium ion secondary battery electrode, which comprises forming an electrode on a collector using the binder for a lithium ion secondary battery electrode according to claim 1 and crosslinking the polyvinyl acetal-based resin (A) by heat or light.

9. A lithium ion secondary battery electrode comprising the binder for a lithium ion secondary battery electrode according to claim 1 and an active material.

10. The lithium ion secondary battery electrode according to claim 9 , wherein the polyvinyl acetal-based resin (A) contained in the binder for a lithium ion secondary battery electrode is from 0.1 to 10 parts by weight based on 100 parts by weight of the active material.

11. A lithium ion secondary battery electrode comprising a crosslinked product of a polyvinyl acetal-based resin (A) containing structural units represented by chemical formulae (1) to (3):

wherein R1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and

wherein R2 is a functional group containing an ethylenically unsaturated bond.

12. A lithium ion secondary battery having the lithium ion secondary battery electrode according to claim 9 .

13. A lithium ion secondary battery having the lithium ion secondary battery electrode according to claim 11 .

Assignees

• Nippon Synthetic Chem Ind Co Ltd

Inventors

• Aoyama Masato
• Aoki Yasuhiro
• Shibutani Mitsuo

Classifications

• C08F8/28

  Condensation with aldehydes or ketones · CPC title

• Y02P70/54

  Cross-Sectional Technologies · mapped topic

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• C09D129/14

  Homopolymers or copolymers of acetals or ketals obtained by polymerisation of unsaturated acetals or ketals or by after-treatment of polymers of unsaturated alcohols · CPC title

• H01M4/139

  Processes of manufacture · CPC title