Separator including resin member formed inside porous substrate, and secondary battery equipped therewith

Patent metadata

Field	Value
Publication number	US-10777795-B2
Application number	US-201615555454-A
Country	US
Kind code	B2
Filing date	Mar 4, 2016
Priority date	Mar 5, 2015
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

The separator for secondary battery, comprising: a porous substrate having a melting temperature or a decomposition temperature of 200° C. or more; and a resin member formed at least inside of the substrate in a plane section that occupies at least a part of a plane along with a thickness direction of the substrate; wherein said resin member is coated on inner surfaces of pores without completely blocking connecting paths that connects pores of the porous member, and wherein a distribution density of the resin member becomes lower toward inside of the substrate.

First claim

The invention claimed is:

1. A separator for secondary battery, comprising:
a porous substrate having a melting temperature of 200° C. or more or a decomposition temperature of 200° C. or more, wherein the substrate is aromatic polyamide or polyimide; and
a resin member formed at least inside of the substrate in a plane section that occupies at least a part of a plane along with a thickness direction of the substrate, the resin member being formed by feeding resin in solvent to a surface of the substrate and drying it, wherein the resin is a water-soluble resin or a water-dispersible resin and the solvent contains pure water;
wherein said resin member is coated on inner surfaces of pores of the porous substrate without completely blocking connecting paths that connect the pores, wherein a distribution density of the resin member becomes lower toward the inside of the substrate, and wherein the resin member is formed on an area that covers more than 0% and 90% or less of a surface of the substrate.

2. The separator for secondary battery according to claim 1 , wherein the substrate includes in its inside a region with no resin member.

3. The separator for secondary battery according to claim 1 , wherein the resin member is 10 wt % or less of the entire separator.

4. The separator for secondary battery according to claim 1 , wherein a porosity of the entire separator is 55% or more and 80% or less.

5. The separator for secondary battery according to claim 1 , wherein a Gurley value of the entire separator is 100 seconds or more and 300 seconds or less.

6. The separator for secondary battery according to claim 1 , wherein the resin is any one of polyvinyl alcohol (PVA), sodium carboxymethyl cellulose (Na-CMC), polyacrylic acid (PAA), and styrene-butadiene rubber (SBR).

7. The separator for secondary battery of claim 1 , wherein the resin member is further coated on the surface of the substrate to form a surface resin layer.

8. The separator for secondary battery of claim 7 , wherein a thickness of the resin member in the surface resin layer is 1 μm or less.

9. The separator for secondary battery of claim 7 , wherein a ratio between an area of the surface of the substrate excluding openings and an area of the resin member on the surface of the substrate is 90% or less.

10. A secondary battery, comprising:
the separator for secondary battery according to claim 1 ;
a battery element having a positive electrode and a negative electrode; and an outer package for packaging the battery element together with an electrolyte.

11. A separator for secondary battery, comprising:
a substrate of a woven fabric having a melting temperature of 200° C. or more or a decomposition temperature of 200° C. or more or a substrate of a non-woven fabric having a melting temperature of 200° C. or more or a decomposition temperature of 200° C. or more, wherein the substrate is polyphenylene sulfide (PPS); and
a resin member formed at least inside of the substrate in a plane section that occupies at least a part of a plane along with a thickness direction of the substrate, the resin member being formed by feeding resin in solvent to a surface of the substrate and drying it, wherein the resin is a water-soluble resin or a water-dispersible resin and the solvent contains pure water;
wherein said resin member is coated on inner surfaces of spaces in the substrate without completely blocking the spaces, wherein a distribution density of the resin member becomes lower toward the inside of the substrate, and wherein the resin member is formed on an area that covers more than 0% and 90% or less of a surface of the substrate.

Assignees

• Nec Corp

Inventors

• Shimura Kenichi
• Yoshida Noboru
• Inoue Kazuhiko

Classifications

• H01M10/0431 Primary

  Cells with wound or folded electrodes (H01M10/045 takes precedence) · CPC title

• H01M50/423

  Polyamide resins · CPC title

• H01M50/42

  Acrylic resins · CPC title

• H01M50/491

  Porosity · CPC title

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title