Separator for secondary batteries with enhanced stability and method of manufacturing the same

• US 10,964,977 B2
• Filed: 08/23/2017
• Issued: 03/30/2021
• Est. Priority Date: 12/26/2016
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Yeo, Yeol Mae, Koh, Ki Seok, Lee, Yoon Sung, Oh, Seung Min, Min, Hong Seok, Choi, Sung Min
• Primary Examiner(s): Douyette, Kenneth J
• Application Number:
  US15/684,260
• Publication Number:
  US 20180183108A1
• Time in Patent Office: 1,315 Days
• CPC Class Codes: C08J 3/12 Powdering or granulating
• CPC Class Codes: C08J 3/18 Plasticising macromolecular compounds plasticisers C08K
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• CPC Class Codes: H01M 10/14 Assembling a group of electrodes or separators
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 50/403 Manufacturing processes of separators, membranes or diaphragms
• CPC Class Codes: H01M 50/414 Synthetic resins, e.g. thermoplastics or thermosetting resins
• CPC Class Codes: H01M 50/44 Fibrous material
• CPC Class Codes: H01M 50/443 Particulate material
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

Disclosed are a separator for secondary batteries with enhanced stability and a method of manufacturing the separator. The separator can prevent self-discharge which may occur when a porous non-woven fabric material is used for a separator; can perform a shutdown function at a high temperature of 200° C. or less; and can avoid even under harsh conditions of high temperatures, deterioration in stability caused by internal short-circuit of positive and negative electrodes. In particular, the separator for secondary batteries of the present invention includes a porous non-woven fabric material impregnated with a baroplastic polymer powder and pores of the porous non-woven fabric material are filled with the baroplastic polymer powder by pressing an assembly of the secondary battery.

Claims

1. A method of manufacturing a separator for a secondary battery, comprising:

(a) impregnating of a porous non-woven fabric material with a baroplastic polymer powder by filtration;

(b) coating surfaces of porous non-woven fabric material impregnated with the baroplastic polymer powder using a binder solution;

(c) drying the binder solution-coated on the porous non-woven fabric material; and

(d) laminating a positive electrode and a negative electrode on the dried porous non-woven fabric material to form an assembly and pressing the assembly,

wherein the baroplastic polymer powder is molded by pressing, and

wherein pores in the porous non-woven fabric material are filled with the baroplastic polymer by molding the baroplastic polymer powder,

wherein the pressing is carried out by hot-pressing at a temperature of about 20°

C. to 100°

C. and at a pressure of about 1 to 4 ton/in²,

wherein the baroplastic polymer powder comprises block copolymer of polystyrene and polyisoprene,

wherein the baroplastic polymer powder has an average particle diameter of about 10 to 100 μ

m, and

wherein an amount of the baroplastic polymer powder is 15% by volume to 60% by volume based on the volume of the porous non-woven fabric material.

2. The method according to claim 1, wherein the porous non-woven fabric material comprises one or more selected from the group consisting of polyolefin, polyimide, aramid, cellulose, polyacrylonitrile, polyester and polyamide.

3. The method according to claim 1, wherein pores of the porous non-woven fabric material has a size of about 1 μ

m to 100 μ

m and the porous non-woven fabric material has porosity of about 20% to 70%.

4. The method according to claim 1, wherein the binder solution is prepared by dissolving at least one binder selected from the group consisting of polyvinylidene fluoride (PVdF), polyester and polyacrylonitrile in N-methyl-2-pyrrolidone (NMP) or N,N-dimethylacetamide (DMAc).