Lithium ion battery and method for forming the same

• US 6,352,797 B1
• Filed: 11/16/1999
• Issued: 03/05/2002
• Est. Priority Date: 03/17/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Yoshida, Yasuhiro, Shiota, Hisashi, Takemura, Daigo, Murai, Michio, Inuzuka, Takayuki, Aihara, Shigeru, Urushibata, Hiroaki, Hamano, Kouji, Aragane, Jun
• Primary Examiner(s): Maples, John S.
• Application Number:
  US09/423,629
• Time in Patent Office: 840 Days
• Field of Search: 296/231, 429/317, 429/316, 429/313, 429/306
• US Class Current: 429/313
• 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 10/058 Construction or manufacture
• CPC Class Codes: H01M 50/414 Synthetic resins, e.g. thermoplastics or thermosetting resins
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: H01M 50/461 with adhesive layers between electrodes and separators
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: H01M 6/188 Processes of manufacture
• CPC Class Codes: H01M 6/40 Printed batteries , e.g. thin film batteries
• 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
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

The invention is a high-performance lithium ion secondary battery which needs no firm case so that it is possible to reduce the size and weight and to design the shape freely and yet which secures high structural strength and safety. The method of the invention for forming a lithium ion battery comprises the step of joining a positive electrode (3) having a positive electrode active material layer (32) joined to a positive electrode current collector (31) and a negative electrode (5) having a negative electrode active material layer (52) joined to a negative electrode current collector (51) with an adhesive resin (6) comprising at least partially a plastic resin being present in parts therebetween and the step of deforming the adhesive resin (6). The method achieves simplification and improvement of productivity in forming a lithium ion battery.

Claims

1. A lithium ion battery comprising a laminate electrode body, said body comprising a positive electrode having a positive electrode active material layer joined to a positive electrode current collector, a negative electrode having a negative electrode active material layer joined to a negative electrode current collector, and an adhesive resin comprising an at least partially plastic resin, said adhesive resin being interposed between the positive electrode and the negative electrode and forming an interface with voids connecting the positive electrode and the negative electrode.

2. A lithium ion battery according to claim 1, characterized in that the plastic resin is a thermoplastic resin.

3. A lithium ion battery claim 1, characterized in that an area of the voids is from 30 to 90% based on an interface area between positive and negative electrodes.

4. A lithium ion battery according to claim 1, characterized in that the positive electrode and the negative electrode are separated by 100 μ

m or smaller.

5. A lithium ion battery according to claim 1, characterized by having a plurality of the laminate electrode bodies.

6. The lithium ion battery of claim 1, wherein the partially plastic resin is a polyolefin.

7. The lithium ion battery of claim 1, wherein the partially plastic resin is a polyglycol.

8. The lithium ion battery of claim 1, wherein the partially plastic resin is a silicon.

9. The lithium ion battery of claim 1, wherein the adhesive resin further comprises an organic or inorganic powder.

10. The lithium ion battery of claim 1, wherein the adhesive resin further comprises a fiber.

11. A method for forming a lithium ion battery according to claim 1 comprising, as constituent elements, a laminate electrode body further comprising a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, a positive electrode current collector, and a negative electrode current collector, the constituent elements being impregnated with an electrolytic solution, comprising joining the positive electrode and the negative electrode with an adhesive resin containing an at least partially plastic resin, forming an interface with voids, and deforming the adhesive resin.

12. A method for forming a lithium ion battery according to claim 1, comprising deforming the adhesive resin by applying at least the pressure that causes the plastic resin to undergo plastic deformation.

13. A method for forming a lithium ion battery according to claim 1, wherein the plastic resin is a thermoplastic resin.

14. A method for forming a lithium ion battery according to claim 13, comprising deforming the adhesive resin by heating.

15. A method for forming a lithium ion battery according to claim 14, comprising heating at or above the temperature at which the thermoplastic resin develops flowability.

16. A method for forming a lithium ion battery according to claim 13, comprising deforming the adhesive resin by applying ultrasonic waves under pressure.