Polyimide coated separators, porous polyimide coatings, lithium batteries, and related methods

Patent metadata

Field	Value
Publication number	US-12555872-B2
Application number	US-202017419312-A
Country	US
Kind code	B2
Filing date	Jan 3, 2020
Priority date	Jan 4, 2019
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

The instant disclosure or invention is preferably directed to a polyimide coated membrane, separator membrane, or separator for a lithium battery such as a high energy or high voltage rechargeable lithium battery and the corresponding battery. The separator preferably includes a porous or microporous polyimide coating or layer on at least one side of a polymeric microporous layer, membrane or film. The polyimide coating or layer may include other polymers, additives, fillers, or the like. The polyimide coating may be adapted, for example, to provide oxidation resistance, to block dendrite growth, to add dimensional and/or mechanical stability, to reduce shrinkage, to add high temperature performance (HTMI function), to prevent electronic shorting at temperatures above 200 deg C., and/or the like. The microporous polymeric base layer may be adapted, at least, to hold liquid, gel, or polymer electrolyte, to conduct ions, and/or to block ionic flow between the anode and the cathode in the event of thermal runaway (shutdown function). The polyimide coated separator may be adapted, for example, to keep the electrodes apart at high temperatures, to provide oxidation resistance, to block dendrite growth, to add dimensional stability, to reduce shrinkage, to add high temperature performance (HTMI function), to prevent electronic shorting at temperatures above 200 deg C., to increase puncture strength, and/or to block ionic flow between the anode and the cathode in the event of thermal runaway (shutdown function). Although secondary lithium battery usage may be preferred, the instant polyimide coated membrane may be used in a battery, cell, primary battery, capacitor, fuel cell, textile, filter, and/or composite, and/or as a layer or component in other applications, devices, and/or the like.

First claim

What is claimed is:

1 . A polyimide coated separator for a high energy or high voltage rechargeable lithium battery, comprising:
a microporous polymeric layer comprising a polyolefinic membrane, and a microporous polyimide coating on at least one side of the microporous polymeric layer; wherein the microporous polyimide coating comprises polyimide and wherein said polyimide of the microporous polyimide coating is an aqueous soluble polyimide, wherein the aqueous soluble polyimide is synthesized from aromatic tetracarboxylic dianhydrides and [4,4′-methylenebis(2-tert-butylaniline)].

2 . The separator according to claim 1 wherein said microporous polyimide coating is adapted to provide oxidation resistance, to block dendrite growth, to add dimensional stability, to reduce shrinkage, to add high temperature performance (HTMi function), to prevent electronic shorting at temperatures above 200 deg C., or combinations thereof.

3 . The separator according to claim 1 wherein said microporous polymeric layer is adapted to hold liquid electrolyte, to conduct ions, and/or to block ionic flow between the anode and the cathode of a cell or battery in the event of thermal runaway (shutdown function).

4 . The separator according to claim 1 wherein said microporous polyimide coating is made microporous by removing particles from a coating formulation of at least an acid, a polyimide and particles.

5 . The separator according to claim 4 , wherein said particles are selected from the group consisting of silica, calcium carbonate, sodium chloride, kaolin, barium sulfate, SiO 2 , Al 2 O 3 , CaCO 3 , TiO 2 , SiS 2 , SiPO 4 , salt, NaCl, and/or mixtures thereof.

6 . The separator according to claim 4 wherein said particles are removed with one or more solvents and the microporous polyimide coating comprises residual solvent.

7 . The separator according to claim 4 wherein said microporous polyimide coating comprises residual acid.

8 . The separator according to claim 1 wherein said microporous polyimide coating includes other polymers, additives, fillers or combinations thereof.

9 . The separator according to claim 1 wherein said polyimide of said microporous polyimide coating is an aqueous soluble co-polyimide.

10 . The separator according to claim 4 wherein before being removed said particles comprise between 20% to 80% by weight of said polyimide and particles mixture.

11 . The separator according to claim 1 wherein said polyolefinic membrane is a polypropylene and/or polyethylene membrane.

12 . The separator according to claim 1 wherein said polyolefinic membrane having a porosity in the range of 20-80%, an average pore size in the range of 0.02 to 1.0 microns, and a Gurley Number in the range of 5 to 300 sec.

13 . The separator according to claim 4 wherein said particles have an average particle size in the range of 0.001 to 10 microns.

14 . The separator according to claim 1 wherein said microporous polyimide coating is at least partially covered by another coating selected from the group consisting of an adhesive or sticky coating, wherein said polyimide coating and/or adhesive or sticky coating comprises a PVDF or PVDF copolymer.

15 . The separator according to claim 1 wherein said separator further comprises another coating on at least one side thereof selected from the group consisting of an adhesive or sticky coating, wherein said microporous polyimide coating and/or adhesive or sticky coating comprises a PVDF or PVDF co-polymer.

16 . The separator according to claim 1 , wherein said microporous polyimide coating further comprises a PVDF or PVDF co-polymer.

17 . The separator according to claim 8 , wherein said microporous polyimide coating further comprises one or more additives comprising a wetting agent, lubricant, flame retardant, nucleating agent, antioxidant, colorant, or combination thereof.

18 . The separator according to claim 8 , wherein said microporous polyimide coating further comprises one or more fillers selected from the group of calcium carbonate, zinc oxide, diatomaceous earth, talc, kaolin, synthetic silica, mica, clay, boron nitride, silicon dioxide, titanium dioxide, barium sulfate, aluminum hydroxide, magnesium hydroxide, or combinations thereof.

19 . The separator according to claim 17 wherein said microporous polyimide coating further comprises an additive comprising a wetting agent selected from the group of ethoxylated alcohols, primary polymeric carboxylic acids, glycols (such as polypropylene glycol and polyethylene glycols), functionalized polyolefins, and combinations thereof.

20 . The separator according to claim 17 wherein said microporous polyimide coating further comprises an additive comprising a lubricant selected from the group silicone, a fluoropolymer, oleamide, stearamide, erucamide, calcium stearate, lithium stearate, or other metallic stearates.

21 . The separator according to claim 17 wherein said microporous polyimide coating further comprises an additive comprising a flame retardant selected from the group of brominated flame retardants, ammonium phosphate, ammonium hydroxide, alumina trihydrate, and phosphate ester.

22 . The separator according to claim 17 wherein said microporous polyimide coating further comprises an additive comprising a nucleating agent comprising a beta-nucleating agents for polypropylene.

Assignees

• Celgard Llc

Inventors

• Zhang Zhengming
• Adams Changqing Wang

Classifications

• H01M50/457

  comprising three or more layers · 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 Primary

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

• H01M50/403

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M10/052 Primary

  Li-accumulators · CPC title