Electrolyte and battery using the same

• US 20050048374A1
• Filed: 07/15/2004
• Published: 03/03/2005
• Est. Priority Date: 07/18/2003
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Yonezawa, Kei
• Granted Patent: US 9,997,803 B2
• Time in Patent Office: Days
• US Class Current: 429/309
• 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 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 2300/0025 Organic electrolyte
• CPC Class Codes: H01M 2300/0094 in the form of layered products, e.g. coatings
• 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

Abstract

Provided are an electrolyte having superior adhesion strength to an electrode and superior permeability into the electrode, and a battery using the electrolyte. An electrolyte comprises, for example, a high molecular weight compound and an electrolyte solution prepared by dissolving an electrolyte salt in a solvent, and the electrolyte is formed through applying a coating solution prepared by dissolving the high molecular weight compound in a mixed solvent to at least either a cathode or an anode. The high molecular weight compound includes a first high molecular weight compound with a weight-average molecular weight of 550,000 or more and a second high molecular weight compound with a weight-average molecular weight of 1,000 or more but not exceeding 300,000. Thereby, the adhesion strength of the electrolyte to the electrode, the permeability of the electrolyte into the electrode and the mechanical strength of the electrolyte can be improved, and the capability of holding a solvent can be improved.

Claims

1. An electrolyte, comprising:

a first high molecular weight compound with a weight-average molecular weight of 550,000 or more; and

a second high molecular weight compound with a weight-average molecular weight of 1,000 or more but not exceeding 300,000.

2. An electrolyte according to claim 1, wherein

each of the first high molecular weight compound and the second high molecular weight compound is a block copolymer of vinylidene fluoride and hexafluoropropylene.

3. An electrolyte according to claim 2, wherein

the ratio of hexafluoropropylene in the block copolymer is within a range of 3% by weight to 7.5% by weight inclusive.

4. An electrolyte according to claim 1, further comprising:

a third high molecular weight compound with a weight-average molecular weight of 300,000 or more but not exceeding 550,000.

5. An electrolyte according to claim 4, wherein

the third high molecular weight compound is a block copolymer of vinylidene fluoride and hexafluoropropylene.

6. An electrolyte according to claim 5, wherein

a ratio of hexafluoropropylene in the block copolymer is within a range of 3% by weight to 7.5% by weight inclusive.

7. An electrolyte according to claim 1, further comprising:

an electrolyte solution prepared by dissolving an electrolyte salt in a solvent,

wherein the ratio of the electrolyte solution is 80% by weight or more.

8. A battery, comprising:

a cathode;

an anode; and

an electrolyte,

wherein the electrolyte comprises;

a first high molecular weight compound with a weight-average molecular weight of 550,000 or more, and

a second high molecular weight compound with a weight-average molecular weight of 1,000 or more but not exceeding 300,000.

9. A battery according to claim 8, wherein

each of the first high molecular weight compound and the second high molecular weight compound is a block copolymer of vinylidene fluoride and hexafluoropropylene.

10. A battery according to claim 9, wherein

a ratio of hexafluoropropylene in the block copolymer is within a range of 3% by weight to 7.5% by weight inclusive.

11. A battery according to claim 8, wherein

the electrolyte further comprises a third high molecular weight compound with a weight-average molecular weight of 300,000 or more but not exceeding 550,000.

12. A battery according to claim 11, wherein

the third high molecular weight compound is a block copolymer of vinylidene fluoride and hexafluoropropylene.

13. A battery according to claim 12, wherein

a ratio of hexafluoropropylene in the block copolymer is within a range of 3% by weight to 7.5% by weight inclusive.

14. A battery according to claim 8, further comprising:

an electrolyte solution prepared by dissolving an electrolyte salt in a solvent,

wherein a ratio of the electrolyte solution is 80% by weight.

15. A battery according to claim 8, wherein

the anode includes an anode material capable of inserting and extracting lithium (Li).

16. A battery according to claim 15, wherein

the anode includes a carbon material.

17. A battery according to claim 8, wherein

the thickness of the anode is 105 g m or more.

18. A battery according to claim 8, wherein

the cathode includes a complex oxide of lithium (Li) and a transition metal.

19. A battery according to claim 8, wherein

the thickness of the cathode is 120 g m or more.

20. A battery according to claim 8, wherein

the electrolyte is formed through applying a coating solution including the first high molecular weight compound and the second high molecular weight compound to at least either the cathode or the anode.