Separator for battery and alkaline battery

• US 7,754,387 B2
• Filed: 06/13/2005
• Issued: 07/13/2010
• Est. Priority Date: 06/17/2004
• Status: Active Grant

• Current Assignee: Kuraray Company Limited
• Original Assignee: Kuraray Company Limited, Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kawai, Hiroyuki, Nagi, Hisashi, Tano, Eiji, Wada, Seiji, Harada, Toshimitsu
• Primary Examiner(s): Ryan; Patrick
• Assistant Examiner(s): LEE, CYNTHIA K
• Application Number:
  US11/570,135
• Publication Number:
  US 20080274409A1
• Time in Patent Office: 1,856 Days
• Field of Search: None
• US Class Current: 429/248
• CPC Class Codes: D21H 13/16 Polyalkenylalcohols; Polyalkenylethers; Polyalkenylesters
• CPC Class Codes: D21H 17/37 Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
• CPC Class Codes: D21H 17/56 Polyamines; Polyimines; Polyester-imides
• CPC Class Codes: H01M 50/454 comprising a non-fibrous layer and a fibrous layer superimposed on one another
• 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 6/08 with cup-shaped electrodes
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber

Abstract

A separator for alkaline batteries which is obtained by bonding 5.0 to 45.0 g/m² of a highly hygroscopic macromolecular compound of the crosslinking type having carboxyl group to a wetlaid nonwoven fabric comprising an alkali-resistant fiber, followed by crosslinking the macromolecular compound, wherein a silicate compound is added to the highly hygroscopic macromolecular compound of the crosslinking type in an amount of 1.0×10⁻⁴ to 10 mg/cm² per unit area of the separator. By adding the silicate compound, absorption of the electrolyte is increased, the electrolyte can be held for a long time, the electric resistance of the separator itself can be kept small, growth of dendrite can be suppressed, short circuit due to the formed dendrite can be prevented, the volume of the negative electrode material can be increased by suppressing the thickness of the separator after absorbing the electrolyte, impact of dropping can be endured, and oxidative degradation in the alkaline dry cells can be suppressed. An alkaline primary battery can be constructed using the separator.

Claims

1. A separator for alkaline primary batteries which is obtained by bonding 5.0 to 45.0 g/m² of a highly hygroscopic macromolecular compound of a crosslinking type having a carboxyl group to a nonwoven fabric of a wet type comprising an alkali-resistant fiber, followed by crosslinking the macromolecular compound, wherein a silicate compound is added to the highly hygroscopic macromolecular compound of a crosslinking type in an amount so that said silicate compound comprises 1.0×

10<sup>−

4</sup> to 5 mg/cm² per unit area of the separator,

wherein the alkali-resistant fiber comprises a polyvinyl alcohol-based fiber,

and the silicate compound is potassium silicate.

2. The separator for alkaline primary batteries according to claim 1, which has a degree of shielding of 15 seconds or greater, a buckling resistance of 1.96 N or greater, a thickness of 0.300 mm or smaller after absorbing an electrolyte and an impedance (an electric resistance) of 1.00 Ω

or smaller.

3. The separator for alkaline primary batteries according to claim 1, wherein said highly hygroscopic macromolecular compound of a crosslinking type having a carboxyl group is at least one compound selected from salts of polyacrylic acid and copolymers of maleic acid.

4. The separator for alkaline primary batteries according to claim 1, wherein said highly hygroscopic macromolecular compound of a crosslinking type having a carboxyl group is potassium polyacrylate.

5. The separator for alkaline primary batteries according to claim 1, wherein the silicate compound is potassium silicate.

6. An alkaline primary battery which is equipped with a separator for alkaline primary batteries according to claim 1.

7. An alkaline primary battery which is equipped with a separator for alkaline primary batteries according to claim 2.

8. An alkaline primary battery which is equipped with a separator for alkaline primary batteries according to claim 3.

9. An alkaline primary battery which is equipped with a separator for alkaline primary batteries according to claim 4.

10. An alkaline primary battery which is equipped with separator for alkaline primary batteries according to claim 5.

11. The separator for alkaline primary batteries according to claim 1, wherein the nonwoven fabric further comprises a rayon fiber.

12. The separator for alkaline primary batteries according to claim 1, wherein the highly hydroscopic macromolecular compound is a carboxymethyl cellulose.

14. The separator for alkaline primary batteries according to claim 1, wherein the highly hydroscopic macromolecular compound is crosslinked with a crosslinking agent selected from the group consisting of glycerol polyglycidyl ether and polyethylene imine.

13. An alkaline primary battery separator, comprising:

a highly hydroscopic macromolecular compound, a nonwoven fabric, an alkali-resistant fiber, and a silicate compound;

wherein the highly hydroscopic macromolecular compound is bonded to the nonwoven fabric,

the nonwoven fabric is a wet type and comprises the alkali-resistant fiber,

the highly hydroscopic macromolecular compound has a carboxyl group and is crosslinked,

the highly hydroscopic macromolecular compound is bonded to the nonwoven fabric in an amount of 5.0 to 45.0 g/m²,

the silicate compound is present in an amount of 1.0×

10.4 to 5 mg/cm² per unit area of the separator,

the alkali resistant fiber comprises a polyvinyl alcohol fiber, and

the silicate compound is potassium silicate.