Method for producing resin film for non-aqueous electrolyte secondary battery and resin film for non-aqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-9478780-B2
Application number	US-201314409561-A
Country	US
Kind code	B2
Filing date	Jun 24, 2013
Priority date	Jun 28, 2012
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

An object of the present invention is to provide a method for producing a resin film for a non-aqueous electrolyte secondary battery that does not inhibit the movement of ions such as lithium ions and that is arranged between a separator and a positive or negative electrode; and a resin film for a non-aqueous electrolyte secondary battery obtained by the production method. The method for producing a resin film for a non-aqueous electrolyte secondary battery comprises the steps of: coating a separator with a resin composition containing a solvent and a vinylidene fluoride copolymer obtained by copolymerizing vinylidene fluoride and a compound represented by formula (1) below (coating step); and drying the separator on which the resin composition has been coated (drying step). In formula (1), R 1 , R 2 , and R 3 are each independently hydrogen atoms, chlorine atoms, or alkyl groups having from 1 to 5 carbons; and X′ is an atomic group having a molecular weight of 472 or less and having a main chain configured from 1 to 19 atoms.

First claim

The invention claimed is:

1. A method for producing a resin film for a non-aqueous electrolyte secondary battery comprising the steps of: coating a separator with a resin composition containing a solvent and a vinylidene fluoride copolymer obtained by copolymerizing vinylidene fluoride and a compound represented by formula (1) below (coating step); and drying the separator on which the resin composition has been coated (drying step):

wherein R 1 , R 2 , and R 3 are each independently hydrogen atoms, chlorine atoms, or alkyl groups having from 1 to 5 carbons; and X′ is an atomic group having a molecular weight of 472 or less and having a main chain configured from 1 to 19 atoms.

2. The method for producing a resin film for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the compound represented by formula (1) is a compound represented by formula (2) below:

wherein R 1 , R 2 , and R 3 are each independently hydrogen atoms, chlorine atoms, or alkyl groups having from 1 to 5 carbons; and X″′ is an atomic group having a molecular weight of 456 or less and having a main chain configured from 1 to 18 atoms.

3. The method for producing a resin film for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the solvent is a mixed solvent of a good solvent and a poor solvent of the vinylidene fluoride copolymer, wherein the good solvent is at least one solvent selected from group consisting of N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylcarbonate, dimethylsulfoxide, hexamethylphosphoramide, dioxane, propylene carbonate, tetrahydrofuran, tetramethylurea, triethyl phosphate, trimethyl phosphate, acetone, methyl ethyl ketone and cyclohexanone, and the poor solvent is at least one solvent selected from group comprising of water, methanol, ethanol and propanol.

4. The method for producing a resin film for a non-aqueous electrolyte secondary battery according to claim 1 , the method further comprising, in between the coating step and the drying step, a step of immersing the separator on which the resin composition has been coated into a poor solvent, wherein the poor solvent is at least one solvent selected from group consisting of water, methanol, ethanol, and propanol.

5. A resin film for a non-aqueous electrolyte secondary battery obtained by the method for producing a resin film for a non-aqueous electrolyte secondary battery described in claim 1 .

Assignees

• Kureha Corp

Inventors

• Inaba Yusaku
• Igarashi Tamito
• Sakai Yuki
• Takeuchi Aya

Classifications

• H01M10/0525 Primary

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

• H01M50/417

  Polyolefins · CPC title

• H01M50/426

  Fluorocarbon polymers · 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

• H01M50/403 Primary

  Manufacturing processes of separators, membranes or diaphragms · CPC title