High tensile strength paper suitable for use in electrochemical cells

Patent metadata

Field	Value
Publication number	US-11078627-B2
Application number	US-201916526135-A
Country	US
Kind code	B2
Filing date	Jul 30, 2019
Priority date	Aug 14, 2018
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

A paper suitable for use as a separator paper in electrochemical cells and an electrochemical cell comprising same, the paper comprising as the sole fibrous components 95 to 100 weight percent fibrils and 0 to 5 weight percent aramid fibrids and having a thickness of 10 to 40 micrometers and a tensile strength of at least 15 megapascals or greater, the fibrils comprising a polymer blend of 80 to 96 weight percent polyparaphenylene terephthalamide and 4 to 20 weight percent of polyvinylpyrrolidone; the fibrils having a diameter of 10 to 2000 nanometers, a length of 0.2 to 3 millimeters, a surface area of 3 to 40 square meters/gram, and a Canadian Standard Freeness of 0 to 10 milliliters.

First claim

What is claimed is:

1. A paper suitable for use as a separator paper in electrochemical cells comprising, as the sole fibrous components:
a) 95 to 100 weight percent fibrils, and
b) 0 to 5 weight percent aramid fibrids;
the paper having a thickness of 10 to 40 micrometers and a tensile strength of at least 15 megapascals or greater,
wherein the fibrils comprise a polymer blend of 80 to 96 weight percent polyparaphenylene terephthalamide and 4 to 20 weight percent of polyvinylpyrrolidone,
the fibrils having
i) diameter of 10 to 2000 nanometers,
ii) a length of 0.2 to 3 millimeters,
iii) a specific surface area of 3 to 40 square meters/gram, and
iv) a Canadian Standard Freeness of 0 to 10 milliliters.

2. The paper of claim 1 having a tensile strength of 100 megapascals or less.

3. The paper of claim 2 having a tensile strength of 50 megapascals or less.

4. The paper of claim 1 having a mean flow pore size of 0.05 to 0.5 micrometers.

5. The paper of claim 1 , wherein the fibrils have a diameter of 10 to 1200 nanometers.

6. An electrochemical cell comprising the paper of claim 1 .

Assignees

• Dupont Safety & Construction Inc

Inventors

• Afshari Mehdi
• Kang Byoung Sam

Classifications

• H01M50/494

  Tensile strength · 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

• H01M50/414

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

• Y02E60/10

  Energy storage using batteries · CPC title