Alkaline battery separator

• US 10,446,820 B2
• Filed: 09/14/2016
• Issued: 10/15/2019
• Est. Priority Date: 09/15/2015
• Status: Active Grant

• Current Assignee: Kuraray Company Limited
• Original Assignee: Kuraray Company Limited
• Inventors: Hayakawa, Tomohiro, Kusunoki, Toshimichi, Kawai, Hiroyuki, Kambe, Koichi
• Primary Examiner(s): D'Aniello, Nicholas P
• Application Number:
  US15/759,627
• Publication Number:
  US 20180269450A1
• Time in Patent Office: 1,126 Days
• CPC Class Codes: H01M 10/24 Alkaline accumulators
• CPC Class Codes: H01M 50/4295 Natural cotton, cellulose or wood
• CPC Class Codes: H01M 50/44 Fibrous material
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An alkaline battery separator having alkali-resistant fibers, beaten cellulose fibers and a binder, wherein an overall freeness, in terms of CSF, is at least 700 ml and at most 765 ml; weight ratios of the alkali-resistant fibers and the beaten cellulose fibers are 28:72 to 72:28; the beaten cellulose fibers comprise mercerized natural wood fibers having a freeness, in terms of CSF, of at least 150 ml and less than 550 ml; and at least a portion of the alkali-resistant fibers is polyvinyl alcohol-based fibers.

Claims

1. An alkaline battery separator, comprising alkali-resistant fibers, beaten cellulose fibers and a binder, wherein:

1) an overall freeness, in terms of CSF, is at least 700 ml and at most 765 ml;

2) weight ratios of the alkali-resistant fibers and the beaten cellulose fibers are 28;

72 to 72;

28;

3) the beaten cellulose fibers comprise mercerized natural wood fibers having a freeness, in terms of CSF, of at least 150 ml and less than 550 ml; and

4) at least a portion of the alkali-resistant fibers is polyvinyl alcohol-based fibers.

2. The alkaline battery separator according to claim 1, wherein said polyvinyl alcohol-based fibers have an in-water dissolution temperature of at least 90°

C.

3. The alkaline battery separator according to claim 1 wherein the binder is a polyvinyl alcohol-based binder.

4. The alkaline battery separator according to claim 1, wherein weight ratios of the alkali-resistant fibers, the beaten cellulose fibers, and the binder are 25 to 60:

25 to 60;

5 to 20.

5. The alkaline battery separator according to claim 1, wherein a freeness of the mercerized natural wood fibers is, in terms of CSF, at least 150 ml and less than 450 ml.

6. The alkaline battery separator according to claim 1, wherein a content of a fibrillated substance of organic solvent-spun cellulose fibers is 10% by weight or less based on the total weight of the alkaline battery separator.

7. The alkaline battery separator according to claim 1, further comprising regenerated cellulose fibers, wherein a content of the regenerated cellulose fibers is 25% by weight or less based on a total weight of the separator.

8. The alkaline battery separator according to claim 1, wherein a fineness of the alkali-resistant fibers is 0.1 to 0.8 dtex.

9. The alkaline battery separator according to claim 1, wherein air permeability of the alkaline battery separator is 13 cc/cm2/sec or lower.

10. The alkaline battery separator according to claim 1, wherein a degree of swelling of the alkaline battery separator in a 35%-KOH water solution at 25°

C. is 41% or lower.

11. The alkaline battery separator according to claim 1, wherein an alkali elution amount of the alkaline battery separator in a 35%-KOH water solution at 60°

C. is 3% or lower.

12. The alkaline battery separator according to claim 1, wherein:

a weight per unit area of the alkaline battery separator is 20 to 50 g/m²; and

a thickness of the alkaline battery separator is 70 to 150 μ

m.

13. An alkaline battery, comprising the alkaline battery separator according to claim 1.

14. The alkaline battery separator according to claim 1, wherein said polyvinyl alcohol-based fibers have an in-water dissolution temperature ranging from 90°

C. to 200°

C.

15. The alkaline battery separator according to claim 1, wherein said polyvinyl alcohol-based fibers have an in-water dissolution temperature ranging from 100°

C. to 150°

C.

16. The alkaline battery separator according to claim 1, wherein said polyvinyl alcohol-based fibers comprise a vinyl alcohol-based polymer which has an average polymerization degree of 1,000 to 5,000 and a saponification degree of 95% by mol or higher.

17. The alkaline battery separator according to claim 1, wherein said polyvinyl alcohol-based fibers comprise a vinyl alcohol-based polymer copolymerized with a distinct copolymer component wherein the copolymerization amount does not exceed 20% by mol.

18. The alkaline battery separator according to claim 1, wherein said polyvinyl alcohol-based fibers are acetalized.