Separator for non-aqueous secondary battery, method for producing the same, and non-aqueous secondary battery

• US 9,368,778 B2
• Filed: 11/12/2012
• Issued: 06/14/2016
• Est. Priority Date: 11/15/2011
• Status: Active Grant

• Current Assignee: Semcorp Global Holdings KFT, Teijin Limited
• Original Assignee: Teijin Limited
• Inventors: Honda, Susumu, Nishikawa, Satoshi
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): GRESO, AARON J
• Application Number:
  US14/356,654
• Publication Number:
  US 20140363726A1
• Time in Patent Office: 1,310 Days
• US Class Current: 1/1
• 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 50/403 Manufacturing processes of separators, membranes or diaphragms
• CPC Class Codes: H01M 50/417 Polyolefins
• CPC Class Codes: H01M 50/426 Fluorocarbon polymers
• CPC Class Codes: H01M 50/457 comprising three or more layers
• CPC Class Codes: H01M 50/461 with adhesive layers between electrodes and separators
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention provides a separator for a non-aqueous secondary battery including a porous substrate and an adhesive layer that is formed on at least one side of the porous substrate and is an aggregate layer of particles that contain a polyvinylidene fluoride resin and have an average particle diameter of from 0.01 μm to 1 μm, in which a content of the particles per one adhesive layer is from 0.1 g/m² to 6.0 g/m².

Claims

1. A separator for a non-aqueous secondary battery, the separator comprising:

a porous substrate; and

an adhesive layer that is formed on at least one side of the porous substrate and is an aggregate layer of particles that contain a polyvinylidene fluoride resin and have an average particle diameter of from 0.01 μ

m to 1 μ

m, in which a content of the particles per one adhesive layer is from 0.1 g/m² to 6.0 g/m²;

wherein the particles retain their particle shapes in the adhesive layer.

2. The separator for a non-aqueous secondary battery according to claim 1, wherein a smoothness of a surface of the adhesive layer is 1.30 or less, wherein the smoothness of the surface is evaluated based on surface area ratio (smoothness) in a 2×

2 μ

m² visual field in AFM observation, using an atomic force microscope (AFM).

3. The separator for a non-aqueous secondary battery according to claim 1, wherein the polyvinylidene fluoride resin is a copolymer that contains structural units derived from vinylidene fluoride in an amount of 50 mol % or more, with respect to a total amount of structural units of the copolymer.

4. The separator for a non-aqueous secondary battery according to claim 1, wherein the adhesive layer is formed on both sides of the porous substrate.

5. The separator for a non-aqueous secondary battery according to claim 4, wherein

a total amount of the particles in the two adhesive layers formed on the porous substrate is from 0.2 g/m² to 12.0 g/m², and

of the two adhesive layers formed on the porous substrate, a difference between an amount of the particles in one adhesive layer and an amount of the particles in the other adhesive layer is 20% by mass or less, with respect to the total amount of the particles in the two adhesive layers.

6. The separator for a non-aqueous secondary battery according to claim 1, wherein the porous substrate is a polyolefin microporous membrane containing polyethylene.

7. The separator for a non-aqueous secondary battery according to claim 6, wherein the polyolefin microporous membrane comprises polyethylene and polypropylene.

8. The separator for a non-aqueous secondary battery according to claim 6, wherein the polyolefin microporous membrane has a multilayer structure having two or more layers, in which at least one layer of the multilayer structure includes polyethylene, and at least one other layer includes polypropylene.

9. A method for producing a separator for a non-aqueous secondary battery, the method including coating a water-based dispersion including particles containing a polyvinylidene fluoride resin, on at least one side of a porous substrate, followed by drying, to form an adhesive layer that is an aggregate layer of the particles, thereby producing the separator for a non-aqueous secondary battery according to claim 1.

10. A non-aqueous secondary battery comprising a positive electrode, a negative electrode, and the separator for a non-aqueous secondary battery according to claim 1, the separator being disposed between the positive electrode and the negative electrode, wherein in the non-aqueous secondary battery, electromotive force is obtained by lithium doping/dedoping.