CELL

• US 20010055719A1
• Filed: 06/19/1998
• Published: 12/27/2001
• Est. Priority Date: 06/20/1997
• Status: Abandoned Application

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: SHIBUYA, MASHIO, NODA, KAZUHIRO, YAMADA, SHINICHIRO, AKASHI, HIROYUKI, SENOO, TADASHI, SEKAI, KOJI, YASUDA, TOSHIKAZU
• Application Number:
  US09/100,404
• Publication Number:
  US 20010055719A1
• Time in Patent Office: Days
• US Class Current: 429/303
• CPC Class Codes: H01M 10/05 Accumulators with non-aqueous electrolyte H01M10/39 takes precedence
• 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 10/0566 Liquid materials
• CPC Class Codes: H01M 2200/10 Temperature sensitive devices
• CPC Class Codes: H01M 2300/0085 Immobilising or gelification of electrolyte
• CPC Class Codes: H01M 50/486 Organic material
• CPC Class Codes: H01M 6/12 with flat electrodes
• CPC Class Codes: H01M 6/164 by the solvent
• CPC Class Codes: H01M 6/166 by the solute
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A lithium cell, having positive and negative electrodes capable of occluding and releasing lithium and a non-aqueous electrolyte. The cell of the present invention includes a positive electrode, a negative electrode and a gelated electrolyte composed of a polyacrylonitrile containing high molecular material, a γ-caprolactone containing non-aqueous solvent and an electrolyte salt mainly comprised of LiPF₆, with the content of γ-caprolactone in the gelated electrolyte being 30 mol % or less. With the gelated electrolyte composed of the polyacrylonitrile containing high molecular material, non-aqueous solvent and the electrolyte salt mainly composed of LiPF₆, a carbide film is formed on the electrode surface, on contact with the flame, as a result of the carbonization of the high molecular material and the carbonization accelerating operation of LiPF₆. This carbide film inhibits inflammation for realizing superior combustion retardant properties.

Claims

1. A cell comprising:

a positive electrode;

a negative electrode;

a gelated electrolyte composed of a high molecular material containing polyacrylonitrile and having solubility parameter of 8 to 15 (cal/cm²)^½

, a mixed solvent and an electrolyte salt mainly composed of LiPF₆, said mixed solvent being a mixture of ethylene carbonate, propylene carbonate and a third non-aqueous solvent which is at least one selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, methyl propionate and ethyl propionate.

2. The cell as recited in

claim 1

containing a mixture of at least one selected from the group consisting of LiN(CF₃SO₂)₂, Li(CF₂SO₂)₃, LiBF₄, LiAsF₆, LiCF₃SO₃, LiClO₄ and NaClO₄ with LiPF₆.

3. The cell as recited in

claim 1

wherein the high molecular material of the gelated electrolyte is 5000 to 500000.

4. The cell as recited in

claim 1

wherein the negative electrode contains one of metal lithium, a lithium alloy and a material capable of occluding and yielding lithium.

5. The cell as recited in

claim 4

wherein the material capable of occluding and yielding lithium is a carbonaceous material.

6. The cell as recited in

claim 1

wherein the positive electrode contains a lithium transition metal compound oxide represented by the general formula Li_xMO₂, where M is one or more transition metal and where 0.05≦

x≦

1.10.

7. A cell comprising:

a positive electrode;

a negative electrode;

a gelated electrolyte composed of a high molecular material containing polyacrylonitrile and having solubility parameter of 8 to 15 (cal/cm²)^½

, a mixed solvent and an electrolyte salt mainly composed of LiPF₆, said mixed solvent being a mixture of ethylene carbonate, γ

-butyrolactone and a third non-aqueous solvent which is at least one selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, methyl propionate and ethyl propionate.

8. The cell as recited in

claim 7

containing a mixture of at least one selected from the group consisting of LiN(CF₃SO₂)₂, Li(CF₂SO₂)₃, LiBF₄, LiAsF₆, LiCF₃SO₃, LiClO₄ and NaClO₄ with LiPF₆.

9. The cell as recited in

claim 7

wherein the high molecular material of the gelated electrolyte is 5000 to 500000.

10. The cell as recited in

claim 7

wherein the negative electrode contains one of metal lithium, a lithium alloy and a material capable of occluding and yielding lithium.

11. The cell as recited in

claim 10

wherein the material capable of occluding and yielding lithium is a carbonaceous material.

12. The cell as recited in

claim 7

wherein the positive electrode contains a lithium transition metal compound oxide represented by the general formula Li_xMO₂, where M is one or more transition metal and where 0.05≦

x≦

1.10.

13. A cell comprising:

a positive electrode;

a negative electrode;

a gelated electrolyte composed of a high molecular material containing polyacrylonitrile and having solubility parameter of 8 to 15 (cal/cm²)^½

, a mixed solvent and an electrolyte salt mainly composed of LiPF₆, said mixed solvent being a mixture of ethylene carbonate, propylene carbonate, γ

-butyrolactone and a fourth non-aqueous solvent which is at least one selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, methyl propionate and ethyl propionate.

14. The cell as recited in

claim 13

containing a mixture of at least one selected from the group consisting of LiN(CF₃SO₂)₂, Li(CF₂SO₂)₃, LiBF₄, LiAsF₆, LiCF₃SO₃, LiClO₄ and NaClO₄ with LiPF₆.

15. The cell as recited in

claim 13

wherein the high molecular material of the gelated electrolyte is 5000 to 500000.

16. The cell as recited in

claim 13

wherein the negative electrode contains one of metal lithium, a lithium alloy and a material capable of occluding and yielding lithium.

17. The cell as recited in

claim 16

wherein the material capable of occluding and yielding lithium is a carbonaceous material.

18. The cell as recited in

claim 13

wherein the positive electrode contains a lithium transition metal compound oxide represented by the general formula Li_xMO₂, where M is one or more transition metal and where 0.05≦

x≦

1.10.

19. A cell comprising:

a positive electrode;

a negative electrode; and

a gelated electrolyte composed of a high molecular material containing polyacrylonitrile, a non-aqueous solvent containing γ

-butyrolactone and an electrolyte salt mainly composed of LiPF₆, the content of γ

-butyrolactone in said gelated electrolyte being 30 mol % or less.

20. The cell as recited in

claim 19

wherein the non-aqueous solvent is a mixed solvent of γ

-butyrolactone and ethylene carbonate.

21. The cell as recited in

claim 19

wherein the non-aqueous solvent is a mixed solvent of γ

-butyrolactone, ethylene carbonate and propylene carbonate.

22. The cell as recited in

claim 19

wherein the negative electrode contains one of metal lithium, a lithium alloy and a material capable of occluding and yielding lithium.

23. The cell as recited in

claim 22

wherein the material capable of occluding and yielding lithium is a carbonaceous material.

24. The cell as recited in

claim 19

wherein the positive electrode contains a lithium transition metal compound oxide represented by the general formula Li_xMO₂, where M is one or more transition metal and where 0.05≦

x≦

1.10.