Gastight, sealed alkaline storage battery in the form of a button cell

US5800947A · kind A · utility

Assignee

• Varta Batterie Aktiengesellschaft · DE

Inventors

• Uwe Kohler · Kelkheim, DE
• Christoph Klaus · Teltow, DE
• Gunter A. Hofmann · San Diego, US
• Frank Lichtenberg · Adliswil, CH

Key dates

• Filing date: Jul 25, 1995
• Grant date: Sep 1, 1998
• Expiry date: Jul 25, 2015

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T29/49108
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A Ni/Cd or Ni/hydride storage battery of the button cell type has a positive electrode tablet based on a nickel hydroxide powder having an active mass comprised of spherical particles with a high pycnometric density (d>3.5 g/cm.sup.3). In contrast to conventional nickel hydroxide powders having irregular particles, a better space utilization is achieved during dry pressing due to a narrow particle-size distribution having a maximum in a range of from 5 to 20 .mu.m, and due to the rounded particle surfaces. The specific volumetric capacity of the resulting button cell electrode is consequently approximately 25% higher than that of a conventional positive button cell electrode. A microporous separator having pore sizes smaller than the mean diameter of the spherical particles prevents the danger of short circuits.