Lithium Ion Secondary Battery And Method For Producing The Same

• US 20080038639A1
• Filed: 04/19/2005
• Published: 02/14/2008
• Est. Priority Date: 04/19/2004
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation), ZEON Corporation
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Hayashi, Tetsuya, Fujino, Akiko, Ohata, Tsumoru, Ikuta, Shigeo, Nakajima, Junji, Nakamura, Eitaro
• Granted Patent: US 7,816,038 B2
• Time in Patent Office: Days
• US Class Current: 429/231.95
• 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 10/0567 characterised by the additives
• CPC Class Codes: H01M 2300/004 Three solvents
• CPC Class Codes: H01M 4/0402 Methods of deposition of the material
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/139 Processes of manufacture
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49115 including coating or impregnating

Abstract

A method for producing a lithium ion secondary battery includes the steps of: forming a positive electrode mixture layer on a positive electrode substrate to obtain a positive electrode; forming a negative electrode mixture layer on a negative electrode substrate to obtain a negative electrode; forming an electronically insulating porous film that is bonded to a surface of at least one of the positive electrode and the negative electrode; interposing a separator between the positive electrode and the negative electrode to form an electrode plate assembly; and impregnating the electrode plate assembly with a non-aqueous electrolyte. The step of forming a porous film includes the steps of: preparing a porous film paste that contains a film binder comprising a thermo-cross-linkable resin and a particulate filler; and applying the porous film paste onto a surface of at least one of the positive electrode and the negative electrode and heating the resultant applied film.

Claims

1. A method for producing a lithium ion secondary battery, comprising the steps of:

forming a positive electrode material mixture layer on a positive electrode substrate to obtain a positive electrode;

forming a negative electrode material mixture layer on a negative electrode substrate to obtain a negative electrode;

forming an electronically insulating porous film that is bonded to a surface of at least one of said positive electrode and said negative electrode;

interposing a separator between said positive electrode and said negative electrode to form an electrode plate assembly; and

impregnating said electrode plate assembly with a non-aqueous electrolyte,

wherein said step of forming a porous film comprises the steps of;

preparing a porous film paste that contains a film binder comprising a thermo-cross-linkable resin and a particulate filler; and

applying said porous film paste onto a surface of at least one of said positive electrode and said negative electrode and heating the resultant applied film.

2. The method for producing a lithium ion secondary battery in accordance with claim 1, wherein said thermo-cross-linkable resin is a single-liquid-type resin with a masked cross-linkable site.

3. The method for producing a lithium ion secondary battery in accordance with claim 1, wherein said thermo-cross-linkable resin comprises a polyacrylonitrile chain.

4. The method for producing a lithium ion secondary battery in accordance with claim 2, wherein said masked cross-linkable site is activated at 100°

C. or higher.

5. The method for producing a lithium ion secondary battery in accordance with claim 1, wherein said applied film is heated at a temperature of 150°

C. or higher.

6. The method for producing a lithium ion secondary battery in accordance with claim 1, wherein said step of heating the applied film is performed in an inert gas.

7. A lithium ion secondary battery comprising:

a positive electrode comprising a positive electrode substrate and a positive electrode material mixture layer carried thereon;

a negative electrode comprising a negative electrode substrate and a negative electrode mixture layer carried thereon;

an electronically insulating porous film bonded to a surface of at least one of said positive electrode and said negative electrode; and

a non-aqueous electrolyte,

wherein said porous film comprises a particulate filler and a film binder, and said film binder comprises a cured thermo-cross-linkable resin.

8. The lithium ion secondary battery in accordance with claim 7, wherein when said cured resin is immersed in said non-aqueous electrolyte at 60°

C. for 72 hours, said cured resin swells with said non-aqueous electrolyte by 700% or less.

9. The lithium ion secondary battery in accordance with claim 8, wherein said non-aqueous electrolyte comprises a non-aqueous solvent and a lithium salt dissolved in said non-aqueous solvent, and said non-aqueous solvent comprises a carbonic acid ester.