Separator paper for alkaline battery and the alkaline battery

• US 20060014080A1
• Filed: 06/16/2005
• Published: 01/19/2006
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Nippon Kodoshi Corporation
• Original Assignee: Nippon Kodoshi Corporation
• Inventors: Ueta, Masahiko, Kubo, Yoshiyo, Hayashi, Yoshitada
• Granted Patent: US 7,781,104 B2
• Time in Patent Office: Days
• US Class Current: 429/255
• CPC Class Codes: D21H 27/00 Special paper not otherwise provided for, e.g. made by multi-step processes
• CPC Class Codes: H01M 10/24 Alkaline accumulators
• CPC Class Codes: H01M 10/30 Nickel accumulators H01M10/34 takes precedence
• CPC Class Codes: H01M 10/32 Silver accumulators H01M10/34 takes precedence
• CPC Class Codes: H01M 12/06 with one metallic and one gaseous electrode
• CPC Class Codes: H01M 50/4295 Natural cotton, cellulose or wood
• CPC Class Codes: H01M 50/44 Fibrous material
• CPC Class Codes: H01M 50/449 having a layered structure
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: H01M 50/494 Tensile strength
• CPC Class Codes: H01M 6/04 Cells with aqueous electrolyte
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

A thin separator paper is provided for separating a positive electrode active material and a negative electrode active material from one another in alkaline battery. The separator paper has high gas tightness, high shortage preventing effect, and low deterioration. The separator paper possesses a crystalline structure in which cellulose 1 and cellulose 2 coexist. A ratio of the cellulose 2 is controlled in relation to the cellulose 1 and the separator paper is made by using an alkali treated pulp beaten from CSF 50 ml to 0 ml, as a raw material. The separator paper has the thickness between 15 μm and 60 μm, the gas tightness between 10 minutes/100 ml and 800 minutes/100 ml, and the area shrinkage rate which is not greater than 2%. Also provided is an alkaline battery containing the separator paper.

Claims

1. A separator paper for isolating a positive electrode active material and a negative electrode active material in an alkaline-battery, said separator paper having a crystalline structure in a form in which cellulose 1 and cellulose 2 co-exist and the ratio of cellulose 2 to cellulose 1 is controlled, wherein the separator paper is prepared from an alkali-treated pulp beaten to a CSF value of 50 to 0 ml.

2. The separator paper for alkaline battery of claim 1, wherein the ratio of cellulose 2 to cellulose 1 is controlled so as to be in the range of from 50% to 85%.

3. The separator paper for alkaline battery of claim 1, wherein said separator paper is formed with a thickness of from 15 μ

m to 60 μ

m and a gas tightness of from 10 min/100 ml to 800 min/100 ml.

4. The separator paper for alkaline battery of claim 1, wherein said separator paper is formed with a thickness of from 15 μ

m to 60 μ

m, a gas tightness of from 10 min/100 ml to 800 min/100 ml, and a surface-area shrinkage rate of less than 2%.

5. The separator paper for alkaline battery of claim 1, wherein the alkali-treated pulp content is from 80% to 100% by weight in said separator paper.

6. The separator paper for alkaline battery of claim 1, wherein the raw material pulp is treated using an aqueous solution of NaOH in a range of concentration from 12% to 17% by weight.

7. The separator paper for alkaline battery of claim 1, wherein the average fiber length of the alkali-treated pulp is in the range of from 0.2 to 0.6 mm.

8. The separator paper for alkaline battery of claim 1, wherein the degree of polymerization is 1,000 or greater in the alkali-treated pulp.

9. The separator paper for alkaline battery of claim 1, wherein the brightness of the alkali-treated pulp is low bleached less than 60%, or unbleached.

10. An alkaline battery comprising a positive electrode active material, a negative electrode active material, and the separator paper of claim 1 isolating the positive electrode active material from the negative electrode active material.

11. The alkaline battery of claim 10, wherein said separator paper is present in a single layer or in double layers.

12. The alkaline battery of claim 10 wherein said separator paper has a thickness ranging from 15 μ

m to 120 μ

m.

13. A separator paper for isolating a positive electrode active material and a negative electrode active material in an alkaline-battery, said separator paper having a crystalline structure in a form in which cellulose 1 and cellulose 2 co-exist and the ratio of cellulose 2 to cellulose 1 is controlled to be in the range of 40% to 90%, wherein the separator paper is prepared from an alkali-treated pulp beaten to a CSF value of 50 to 0 ml.

14. The separator paper for alkaline battery of claim 13, wherein the ratio of cellulose 2 to cellulose 1 is controlled so as to be in the range of from 50% to 85%.

15. The separator paper for alkaline battery of claim 13, wherein said separator paper is formed with a thickness of from 15 μ

m to 60 μ

m and a gas tightness of from 10 min/100 ml to 800 min/100 ml.

16. The separator paper for alkaline battery of claim 13, wherein said separator paper is formed with a thickness of from 15 μ

m to 60 μ

m, a gas tightness of from 10 min/100 ml to 800 min/100 ml, and a surface-area shrinkage rate of less than 2%.

17. The separator paper for alkaline battery of claim 13, wherein the alkali-treated pulp content is from 80% to 100% by weight in said separator paper.

18. The separator paper for alkaline battery of claim 13, wherein the raw material pulp is treated using an aqueous solution of NaOH in a range of concentration from 12% to 17% by weight.

19. The separator paper for alkaline battery of claim 13, wherein the average fiber length of the alkali-treated pulp is in the range of from 0.2 to 0.6 mm.

20. The separator paper for alkaline battery of claim 13, wherein the degree of polymerization is 1,000 or greater in the alkali-treated pulp.

21. The separator paper for alkaline battery of claim 13, wherein the brightness of the alkali-treated pulp is low bleached less than 60%, or unbleached.

22. An alkaline battery comprising a positive electrode active material, a negative electrode active material, and the separator paper of claim 13 isolating the positive electrode active material from the negative electrode active material.

23. The alkaline battery of claim 22, wherein said separator paper is present in a single layer or in double layers.

24. The alkaline battery of claim 22, wherein said separator paper has a thickness ranging from 15 μ

m to 120 μ

m.

25. A method of making a separator paper for isolating a positive electrode active material and a negative electrode active material in an alkaline-battery, the method comprising:

providing an alkali-treated pulp beaten to a CSF value of 50 to 0 ml; and

processing the alkali-treated pulp into separator paper having a crystalline structure in a form in which cellulose 1 and cellulose 2 co-exist, and controlling a ratio of cellulose 2 to cellulose 1.

26. The method of claim 25, wherein the ratio of cellulose 2 to cellulose 1 is in the range of 40% to 90%.

27. A method of making an alkaline battery comprising:

making the separator paper with the method of claim 25;

interposing the separator paper between a positive electrode active material and a negative electrode active material to isolate the electrode active materials from one another.