Battery cell and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-12438237-B2
Application number	US-202118008336-A
Country	US
Kind code	B2
Filing date	Jul 16, 2021
Priority date	Jul 16, 2020
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

A battery cell including an electrode assembly present in a battery casing. The electrode assembly includes a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode. The separator includes a porous polymer substrate, a first organic/inorganic porous coating layer on at least one surface of the porous polymer substrate, and a second organic/inorganic porous coating layer on a surface of the first organic/inorganic porous coating layer. The first organic/inorganic porous coating layer includes first inorganic particles and a first binder polymer, the second organic/inorganic porous coating layer includes second inorganic particles and a second binder polymer, the second organic/inorganic porous coating layer faces the positive electrode, and the second binder polymer has a weight average molecular weight higher than the weight average molecular weight of the first binder polymer.

First claim

What is claimed is:

1. A battery cell, comprising:
an electrode assembly present in a battery casing,
wherein the electrode assembly comprises a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode,
wherein the separator comprises a porous polymer substrate, a first organic/inorganic porous coating layer on at least one surface of the porous polymer substrate, and a second organic/inorganic porous coating layer on a surface of the first organic/inorganic porous coating layer,
wherein the first organic/inorganic porous coating layer comprises first inorganic particles and a first binder polymer,
wherein the second organic/inorganic porous coating layer comprises second inorganic particles and a second binder polymer,
wherein the second organic/inorganic porous coating layer faces the positive electrode, and
wherein the second binder polymer has a weight average molecular weight higher than a weight average molecular weight of the first binder polymer.

2. The battery cell according to claim 1 , wherein the weight average molecular weight of the second binder polymer ranges from 800,000 to 1,500,000.

3. The battery cell according to claim 1 , wherein the weight average molecular weight of the first binder polymer ranges from 300,000 to 600,000.

4. The battery cell according to claim 1 , wherein the first organic/inorganic porous coating layer has a thickness larger than a thickness of the second organic/inorganic porous coating layer.

5. The battery cell according to claim 4 , wherein a ratio of the thickness of the first organic/inorganic porous coating layer to the thickness of the second organic/inorganic porous coating layer is 6:4 to 9:1.

6. The battery cell according to claim 1 , wherein each of the first binder polymer and the second binder polymer is at least one independently selected from the group consisting of polyvinylidene fluoride (PVDF), hexafluoropropylene (HFP), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polybutyl acrylate, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, acrylonitrile-styrene-butadiene copolymer and polyimide.

7. The battery cell according to claim 1 , wherein an adhesion between the separator and the positive electrode is 40 gf/25 mm or more.

8. The battery cell according to claim 1 , wherein the first binder polymer is the same as or different from the second binder polymer.

9. The battery cell according to claim 1 , wherein the first inorganic particles are the same or different from the second inorganic particles.

Assignees

• Lg Energy Solution Ltd

Inventors

• Park Jun-Soo
• Jung Bum-Young

Classifications

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M50/426

  Fluorocarbon polymers · CPC title

• H01M50/434

  Ceramics · 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

• H01M50/457

  comprising three or more layers · CPC title