Negative electrode for secondary batteries and method for producing same

Patent metadata

Field	Value
Publication number	US-9793527-B2
Application number	US-201314400932-A
Country	US
Kind code	B2
Filing date	May 29, 2013
Priority date	May 30, 2012
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A secondary battery negative electrode including a current collector, a negative electrode active material layer, and a porous membrane, wherein the negative electrode active material layer contains a negative electrode active material and a particulate negative electrode polymer, the porous membrane contains non-conductive particles and a porous membrane polymer that is a non-particulate cross-linked polymer, and the non-conductive particles are particles of a polymer that contains 50% by weight or more of a structural unit formed by polymerization of a (meth)acrylate, the polymer having a softening starting point or decomposition point of 175° C. or higher.

First claim

The invention claimed is:

1. A secondary battery negative electrode comprising a current collector, a negative electrode active material layer, and a porous membrane, wherein
the negative electrode active material layer contains a negative electrode active material and a particulate negative electrode polymer,
the porous membrane contains non-conductive particles and a porous membrane polymer that is a non-particulate cross-linked polymer, and
the non-conductive particles are particles of a polymer that contains 98.8% by weight or more and 100% by weight or less of a structural unit formed by polymerization of a (meth)acrylate, the polymer having a softening starting point or decomposition point of 175° C. or higher.

2. The secondary battery negative electrode according to claim 1 , wherein the porous membrane polymer includes a cross-linked structure formed by one or more types of groups selected from the group consisting of an epoxy group, a carboxyl group, and a sulfo group.

3. The secondary battery negative electrode according to claim 1 , wherein
a number average particle diameter of the non-conductive particles is 100 nm to 2,000 nm, and
a variation coefficient in diameter of the non-conductive particles is 26% or less.

4. The secondary battery negative electrode according to claim 1 , wherein the negative electrode active material is a composite particle containing a material including silicon.

5. The secondary battery negative electrode according to claim 1 wherein the negative electrode active material contains a combination of carbon and one or both of metallic silicon and a silicon-based active material.

6. The secondary battery negative electrode according to claim 1 wherein the porous membrane polymer contains a structural unit formed by polymerization of a (meth)acrylic acid ester.

7. The secondary battery negative electrode according to claim 1 wherein an amount of the porous membrane polymer in the porous membrane based on 100 parts by weight of the non-conductive particles is 2 parts by weight or more and 37 parts by weight or less.

8. A secondary battery comprising a positive electrode, a negative electrode, an electrolytic solution, and a separator, wherein the negative electrode is the secondary battery negative electrode according to claim 1 .

9. A method for producing a secondary battery negative electrode including a current collector, a negative electrode active material layer, and a porous membrane, the method comprising:
applying a negative electrode slurry containing a negative electrode active material, a particulate negative electrode polymer, and water onto the current collector and then drying the negative electrode slurry to thereby obtain the negative electrode active material layer;
applying a porous membrane slurry onto the negative electrode active material layer and drying the applied porous membrane slurry, the porous membrane slurry containing: non-conductive particles that are particles of a polymer that includes 98.8% by weight or more and 100% by weight or less of a structural unit formed by polymerization of a (meth)acrylate and has a softening starting point or decomposition point of 175° C. or higher; a porous membrane polymer that is a non-particulate cross-linkable polymer; and a solvent; and
cross-linking the porous membrane polymer by heating.

10. The method for producing a secondary battery negative electrode according to claim 9 , wherein
the porous membrane slurry contains two or more types of solvents, and
the difference in boiling point between the two or more types of solvents is 40° C. or more.

Assignees

• Zeon Corp

Inventors

• Kaneda Takuya

Classifications

• H01M4/366

  as layered products · CPC title

• H01M4/139

  Processes of manufacture · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/62

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

• H01M4/60

  of organic compounds · CPC title