Electrode with porous protective film, nonaqueous electrolyte secondary battery, and method for manufacturing electrode with porous protective film

Patent metadata

Field	Value
Publication number	US-9236606-B2
Application number	US-48128909-A
Country	US
Kind code	B2
Filing date	Jun 9, 2009
Priority date	Jun 11, 2008
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

An electrode with a porous protective film includes an electrode in which an active material layer is disposed on a collector and a porous protective film which is disposed on a surface of the active material layer and which contains fine particles, a binder, a surfactant, and a thickener. A nonaqueous electrolyte secondary battery includes a negative electrode in which a negative electrode active material layer is disposed on a negative electrode collector, a positive electrode in which a positive electrode active material layer is disposed on a positive electrode collector, a nonaqueous electrolyte, a separator, and a porous protective film which is disposed on at least one of a surface of the negative electrode active material layer or a surface of the positive electrode active material layer and which contains fine particles, a binder, a surfactant, and a thickener.

First claim

The application is claimed as follows:

1. An electrode with a porous protective film, the electrode comprising:
an electrode in which an active material layer is disposed on a collector; and
a porous protective film which is disposed on a surface of the active material layer and which contains fine particles, a binder, a surfactant, and a thickener that is soluble in a solvent of a slurry used to form the porous protective film,
wherein a weight ratio of the thickener to the fine particles in the porous protective film ranges from 0.10 to 0.20.

2. The electrode with a porous protective film according to claim 1 , wherein the thickener comprises at least one type selected from the group consisting of hydroxyethyl cellulose, carboxymethyl cellulose, and polyethylene glycol.

3. The electrode with a porous protective film according to claim 1 , wherein the surfactant comprises at least one type selected from the group consisting of sodium dodecyl sulfate, lithium dodecyl sulfate, and sodium hexametaphosphate.

4. The electrode with a porous protective film according to claim 1 , wherein the fine particles comprises a metal oxide.

5. The electrode with a porous protective film according to claim 4 , wherein the metal oxide comprises at least one type selected from the group consisting of alumina, titania, zirconia, and silica.

6. The electrode with a porous protective film according to claim 1 , wherein the air permeability of the porous protective film is 3 to 600 sec/100 ml.

7. The electrode with a porous protective film according to claim 1 , wherein a thickness of the porous protective film ranges from 0.1 μm to 200 μm.

8. The electrode with a porous protective film according to claim 1 , wherein the binder contains a fluorine resin and a rubber resin, and the rubber resin comprises at least one type selected from the group consisting of styrene-butadiene rubber, acrylic rubber, and butadiene rubber.

9. A nonaqueous electrolyte secondary battery comprising:
a negative electrode in which a negative electrode active material layer is disposed on a negative electrode collector;
a positive electrode in which a positive electrode active material layer is disposed on a positive electrode collector;
a nonaqueous electrolyte;
a separator; and
a porous protective film which is disposed on at least one of a surface of the negative electrode active material layer and a surface of the positive electrode active material layer and which contains fine particles, a binder, a surfactant, and a thickener that is soluble in a solvent of a slurry used to form the porous protective film,
wherein a weight ratio of the thickener to the fine particles in the porous protective film ranges from 0.10 to 0.20.

10. The nonaqueous electrolyte secondary battery according to claim 9 , wherein a thickness of the porous protective film ranges from 0.1 μm to 200 μm.

11. A method for manufacturing an electrode with a porous protective film, the method comprising the steps of:
preparing a porous protective film-forming slurry by mixing fine particles, a binder, a surfactant, a solvent, and a thickener that is soluble in the solvent; and
applying the porous protective film-forming slurry to an electrode, in which an active material layer is disposed on a collector, and
conducting drying to form the porous protective film,
wherein a weight ratio of the thickener to the fine particles in the porous protective film ranges from 0.10 to 0.20.

12. The method for manufacturing an electrode with a porous protective film according to claim 11 , wherein a concentration of the thickener in the porous protective film-forming slurry is 0.50 to 1.0 percent by mass.

13. The method for manufacturing an electrode with a porous protective film according to claim 11 , wherein a concentration of the surfactant in the porous protective film-forming slurry is 0.01 to 3.0 percent by mass.

14. The method for manufacturing an electrode with a porous protective film according to claim 11 , wherein a thickness of the porous protective film ranges from 0.1 μm to 200 μm.

15. The method for manufacturing an electrode with a porous protective film according to claim 11 , wherein a viscosity of the slurry ranges from 0.1 Pa·s to 3.5 Pa·s.

Assignees

• Tadano Junichi
• Sony Corp

Inventors

• Tadano Junichi

Classifications

• H01M4/13 Primary

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• Y10T29/49115

  including coating or impregnating · CPC title

• H01M4/622

  being polymers · CPC title

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• H01M4/139 Primary

  Processes of manufacture · CPC title