ELECTROCHEMICAL DEVICE AND METHOD FOR PRODUCTION THEREOF

• US 20090325058A1
• Filed: 05/08/2008
• Published: 12/31/2009
• Est. Priority Date: 05/10/2007
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Maxell Holdings, Ltd.
• Inventors: Abe, Toshihiro, Katayama, Hideaki, Matsumoto, Nobuaki
• Granted Patent: US 10,862,091 B2
• Time in Patent Office: Days
• US Class Current: 429/142
• CPC Class Codes: H01G 9/02 Diaphragms; Separators
• CPC Class Codes: H01M 10/0431 Cells with wound or folded electrodes H01M10/045 takes precedence
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• CPC Class Codes: H01M 50/449 having a layered structure
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• 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

An electrochemical device of the present invention includes a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator. The separator includes a first porous layer composed mainly of a thermoplastic resin and a second porous layer composed mainly of insulating particles with a heat-resistant temperature of 150° C. or higher. The first porous layer is disposed to face the negative electrode.

Claims

1. An electrochemical device comprising:

a positive electrode;

a negative electrode;

a non-aqueous electrolyte; and

a separator,

wherein the separator comprises a first porous layer composed mainly of a thermoplastic resin and a second porous layer composed mainly of insulating particles with a heat-resistant temperature of 150°

C. or higher, and

the first porous layer is disposed to face the negative electrode.

2. The electrochemical device according to claim 1, wherein the thermoplastic resin has a melting point of 80 to 140°

C.

3. The electrochemical device according to claim 1, wherein the thermoplastic resin has a melt viscosity of 1000 mPa·

s or more at 140°

C.

4. The electrochemical device according to claim 1, wherein the thermoplastic resin has a melt viscosity of 1000000 mPa·

s or less at 140°

C.

5. The electrochemical device according to claim 1, wherein at least one of the first porous layer and the second porous layer includes plate-like particles.

6. The electrochemical device according to claim 1, wherein a part or the whole of the insulating particles included in the second porous layer is made of plate-like particles.

7. The electrochemical device according to claim 1, wherein at least one of the first porous layer and the second porous layer includes secondary particles formed by agglomeration of primary particles.

8. The electrochemical device according to claim 1, wherein a part or the whole of the insulating particles included in the second porous layer is made of secondary particles formed by agglomeration of primary particles.

9. The electrochemical device according to claim 1, wherein the insulating particles are particles of at least one inorganic oxide selected from the group consisting of alumina, silica, titanium oxide, zirconium oxide, and boehmite.

10. The electrochemical device according to claim 1, wherein the insulating particles have a number average particle size of 0.01 to 15 μ

m.

11. The electrochemical device according to claim 1, wherein the thermoplastic resin is at least one resin selected from the group consisting of polyethylene, polypropylene, and copolymerized polyolefin.

12. The electrochemical device according to claim 1, wherein at least one of the first porous layer and the second porous layer includes an organic binder.

13. The electrochemical device according to claim 1, wherein at least one of the first porous layer and the second porous layer includes a porous matrix with a heat-resistant temperature of 150°

C. or higher.

14. The electrochemical device according to claim 1, wherein the first porous layer and the second porous layer share a porous matrix with a heat-resistant temperature of 150°

C. or higher.

15. The electrochemical device according to claim 13, wherein the porous matrix is formed of a fibrous material with a heat-resistant temperature of 150°

C. or higher.

16. The electrochemical device according to claim 15, wherein the fibrous material includes at least one type of material selected from the group consisting of cellulose and its modified product, polyolefin, polyester, polyacrylonitrile, aramid, polyamide imide, polyimide, and an inorganic oxide.

17. The electrochemical device according to claim 13, wherein the porous matrix is formed of a woven fabric or a nonwoven fabric.

18. The electrochemical device according to claim 1, wherein a ratio X/Y of a thickness X of the first porous layer to a thickness Y of the second porous layer is 10 or less.

19. The electrochemical device according to claim 1, wherein the second porous layer has a thickness of 10 μ

m or less.

20. The electrochemical device according to claim 1, wherein at least one of the first porous layer and the second porous layer is integrated with the electrode.

21. The electrochemical device according to claim 1, wherein the first porous layer and the second porous layer are laminated together in the electrochemical device to form the separator.

22. The electrochemical device according to claim 1, further comprising a mechanism for discharging a gas contained in the electrochemical device to the outside when a pressure of the gas is raised.

23. The electrochemical device according to claim 1, wherein the negative electrode comprises a negative electrode active material containing layer, and the first porous layer is in contact with the negative electrode active material containing layer.

24. A method for manufacturing an electrochemical device comprising a spiral electrode body that comprises a positive electrode, a negative electrode, and a separator, wherein the separator has different friction coefficients on both sides,

the method comprising:

wrapping the separator around a winding shaft with its lower friction coefficient side facing the winding shaft; and

winding the positive electrode and the negative electrode with the separator.

25. A method for manufacturing an electrochemical device comprising a spiral electrode body that comprises a positive electrode, a negative electrode, and a separator, wherein the separator comprises a first porous layer composed mainly of a thermoplastic resin on one side and a second porous layer composed mainly of insulating ceramics particles with a heat-resistant temperature of 150°

C. or higher on the other side,

the method comprising;

wrapping the separator around a winding shaft with the first porous layer facing the winding shaft; and

winding the positive electrode and the negative electrode with the separator.

26. The method according to claim 25, wherein a coefficient of static friction between the first porous layer and the winding shaft is 0.5 or less.

27. The method according to claim 25, wherein a coefficient of static friction between the first porous layer and the winding shaft is 0.05 or more.

28. The method according to claim 25, wherein the negative electrode is located on the first porous layer side of the separator.