# US 12,002,988 B2 · Porous film including porous base and porous layer having inorganic particles and resin particles containing fluoro (meth)acrylate-containing or silicon-containing polymer, separator for secondary batteries, and secondary battery

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- Number: US 12,002,988 B2
- Document ID: US12002988B2
- Status: Granted
- Kind: B2
- Application number: 17/294,874
- Filed: 2019-11-20
- Published: 2022-01-13
- Granted: 2024-06-04
- Earliest claimed: 2018-11-22
- Assignees: Toray Industries, Inc.
- Applicants: Toray Industries, Inc.
- Inventors: Nobuyasu Kai; Keiichi Kamon; Akimitsu Tsukuda
- Web page: https://patentgrep.com/patent/US12002988B2

## CPC

- H01M 50/426: Fluorocarbon polymers
- H01M 50/446: Composite material consisting of a mixture of organic and inorganic materials
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 50/403: Manufacturing processes of separators, membranes or diaphragms
- H01M 50/414: Synthetic resins, e.g. thermoplastics or thermosetting resins
- H01M 50/417: Polyolefins
- H01M 50/443: Particulate material
- H01M 50/449: having a layered structure
- H01M 50/451: comprising layers of only organic material and layers containing inorganic material
- H01M 50/489: Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M 50/491: Porosity
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A low cost porous film has high thermal dimensional stability and good adhesion with electrodes and also has excellent battery characteristics. The porous film includes a porous base and a porous layer containing particles A and particles B disposed at least on one side thereof, wherein the particles A contain a polymer having at least one selected from the monomer unit group a that consists of fluorine-containing (meth)acrylate monomer units and silicon-containing monomer units whereas the particles B are inorganic particles.

## Claims

### Claim 1

A porous film comprising:
a porous base; and
a porous layer containing particles A and particles B disposed at least on one side thereof, wherein the particles A contain a copolymer containing:
at least one selected from a monomer unit group a that consists of fluorine-containing (meth)acrylate monomer units and silicon-containing monomer units; and
at least one monomer unit selected from a monomer unit group b that consists of acrylate monomer units having monocyclic hydrocarbon groups and methacrylate monomer units having monocyclic hydrocarbon groups, and
wherein the particles B are inorganic particles,
wherein the particles B present in the porous layer account for 70 mass % or more and 93 mass % or less of the total quantity, which accounts for 100 mass %, of all constituent components of the porous film,
wherein the monomer units selected from the monomer unit group a and present in the particles A account for 25 mass % or more and 80 mass % or less, and
wherein the particles A have a glass transition temperature of 30° C. or more and 80° C. or less.

### Claim 2 (depends on 1)

The porous film as set forth in claim 1, wherein the particles A are organic resin particles.

### Claim 3 (depends on 1)

The porous film as set forth in claim 1, wherein the copolymer of the particles A has a fluorine-containing (meth)acrylate monomer unit.

### Claim 4 (depends on 1)

The porous film as set forth in claim 1, wherein a fluorine-containing (meth)acrylate monomer present in the fluorine-containing (meth)acrylate monomer unit has 3 or more and 13 or less fluorine atoms.

### Claim 5 (depends on 1)

The porous film as set forth in claim 1, wherein the particles A contains a crosslinking agent accounting for 1 mass % or more and 10 mass % or less.

### Claim 6 (depends on 1)

The porous film as set forth in claim 1, wherein a thickness of the porous layers is more than 1.0 μm and 8.0 μm or less.

### Claim 7 (depends on 1)

The porous film as set forth in claim 1, wherein a ratio of change in air permeability between before and after immersion for 24 hours in a solvent containing at least one of dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate at 25° C. is 1.0 or more and 3.0 or less.

### Claim 8 (depends on 1)

A secondary battery separator comprising the porous film as set forth in claim 1.

### Claim 9 (depends on 8)

A secondary battery comprising a secondary battery separator as set forth in claim 8.