Secondary battery

Patent metadata

Field	Value
Publication number	US-11380963-B2
Application number	US-201716094353-A
Country	US
Kind code	B2
Filing date	Apr 18, 2017
Priority date	Apr 20, 2016
Publication date	Jul 5, 2022
Grant date	Jul 5, 2022

Abstract

Provided is a battery comprising a separator comprising inorganic particles for preventing a short-circuit, wherein the inorganic particles are not removed readily from the separator. This battery is characterized by comprising a separator comprising a base material resin having voids and an inorganic particle having a surface (A) facing the void and a surface (B) in contact with the resin, wherein the length of the surface (A) is 50% or more of the length of the outer periphery of the particle in a cross-sectional SEM photograph of the separator.

First claim

The invention claimed is:

1. A battery comprising a separator, the separator comprising
a porous resin membrane having voids and
inorganic particles,
wherein the inorganic particles contained in the separator account for 5 vol % or more of the separator,
wherein the separator is obtained by bringing an initial composite membrane comprising a resin and the inorganic particles into contact with a removing solution capable of dissolving the inorganic particles to remove 5 vol % to 70 vol % of the inorganic particles to form the voids,
wherein 50% or more of the inorganic particles contained in the separator have a surface (A) facing one of the voids and a surface (B) in contact with the resin, wherein the length of the surface (A) is 50% or more of the length of the outer periphery of the particle in a cross-sectional SEM photograph of the separator, and
wherein the voids which are not open on a surface of the separator have a shape in which (the length in the thickness direction)/(the length in an in-plane direction) is 0.3 or more.

2. The battery according to claim 1 , wherein the inorganic particles are selected from the group consisting of aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, aluminum nitride, and silicon nitride.

3. The battery according to claim 1 , wherein the resin has a melting temperature and/or a decomposition temperature of 200° C. or more.

4. The battery according to claim 3 , wherein the resin is at least one selected from the group consisting of polyethylene terephthalate, aramid, polyimide, polyamideimide, and polyphenylene sulfide.

5. A manufacturing method for a battery comprising the steps of:
fabricating an electrode element by stacking a negative electrode and a positive electrode via a separator, and
encapsulating the electrode element and an electrolyte solution into an outer package,
wherein the separator comprises a porous resin membrane having voids and inorganic particles,
wherein the inorganic particles contained in the separator account for 5 vol % or more of the separator,
wherein the separator is obtained by bringing an initial composite membrane comprising a resin and the inorganic particles into contact with a removing solution capable of dissolving the inorganic particles to remove 5 vol % to 70 vol % of the inorganic particles to form the voids,
wherein 50% or more of the inorganic particles contained in the separator have a surface (A) facing one of the voids and a surface (B) in contact with the resin, wherein the length of the surface (A) is 50% or more of the length of the outer periphery of the particle in a cross-sectional SEM photograph of the separator, and
wherein the voids which are not open on a surface of the separator have a shape in which (the length in the thickness direction)/(the length in an in-plane direction) is 0.3 or more.

6. The battery according to claim 1 , wherein the inorganic particles are present inside the one of the voids.

Assignees

• Nec Corp

Inventors

• Shimura Kenichi
• Inoue Kazuhiko

Classifications

• H01M50/491

  Porosity · CPC title

• H01M50/414

  Synthetic resins, e.g. thermoplastics or thermosetting resins · CPC title

• H01M50/437

  Glass · CPC title

• H01M50/446 Primary

  Composite material consisting of a mixture of organic and inorganic materials · CPC title

• H01M10/049

  Processes for forming or storing electrodes in the battery container · CPC title