SEPARATOR FOR NONAQUEOUS SECONDARY BATTERY, AND NONAQUEOUS SECONDARY BATTERY

• US 20130095365A1
• Filed: 10/21/2011
• Published: 04/18/2013
• Est. Priority Date: 04/08/2011
• Status: Active Grant

• Current Assignee: Teijin Limited
• Original Assignee: Teijin Limited
• Inventors: Nishikawa, Satoshi
• Granted Patent: US 9,269,938 B2
• Time in Patent Office: Days
• US Class Current: 429/145
• CPC Class Codes: H01M 2008/1293 Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 50/406 Moulding; Embossing; Cutting
• CPC Class Codes: H01M 50/417 Polyolefins
• CPC Class Codes: H01M 50/426 Fluorocarbon polymers
• CPC Class Codes: H01M 50/44 Fibrous material
• CPC Class Codes: H01M 50/451 comprising layers of only organic material and layers containing inorganic material
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An object of the invention is to provide a separator for a nonaqueous secondary battery, which has good adhesion to electrodes and is also capable of ensuring sufficient ion permeability even after attachment to an electrode. The separator for a nonaqueous secondary battery of the invention includes a porous substrate and an adhesive porous layer formed on at least one side of the porous substrate and containing a polyvinylidene-fluoride-based resin. The separator for a nonaqueous secondary battery is characterized in that the adhesive porous layer has a crystallinity of 20 to 35%.

Claims

1. A separator for a nonaqueous secondary battery, comprising a porous substrate and an adhesive porous layer that is formed on at least one side of the porous substrate and contains a polyvinylidene-fluoride-based resin,

the separator for a nonaqueous secondary battery being characterized in that the adhesive porous layer has a crystallinity of 20 to 35%.

2. The separator for a nonaqueous secondary battery according to claim 1, characterized in that the weight of the adhesive porous layer formed on one side of the porous substrate is 0.5 to 1.5 g/m².

3. The separator for a nonaqueous secondary battery according to claim 1, characterized in that the adhesive porous layer is formed on both front and back sides of the porous substrate.

4. The separator for a nonaqueous secondary battery according to claim 3, characterized in that

the total weight of the adhesive porous layers formed on both sides of the porous substrate is 1.0 g/m² or more and 3.0 g/m² or less, and

the difference between the weight of the adhesive porous layer on one side and the weight of the adhesive porous layer on the other side is 20% or less of the total weight on both sides.

5. The separator for a nonaqueous secondary battery according to claim 1, characterized in that the value obtained by subtracting the Gurley value of the porous substrate from the Gurley value of the separator for a nonaqueous secondary battery with the adhesive porous layer formed thereon is 300 sec/100 cc or less.

6. The separator for a nonaqueous secondary battery according to claim 1, characterized in that the porous substrate is a polyolefin microporous membrane containing polyethylene.

7. The separator for a nonaqueous secondary battery according to claim 1, characterized in that the porous substrate is a polyolefin microporous membrane containing polyethylene and polypropylene.

8. The separator for a nonaqueous secondary battery according to claim 7, characterized in that the polyolefin microporous membrane includes at least two layers with one of the two layers containing polyethylene and the other layer containing polypropylene.

9. A nonaqueous secondary battery comprising the separator according to claim 1.

10. The separator for a nonaqueous secondary battery according to claim 2, characterized in that the adhesive porous layer is formed on both front and back sides of the porous substrate.