About batteries: the tubular plate

In the Electrical world, 1890,Volume 16, a Mr S Currie is reported yo have designed a tubular positive plate. The plate derives its strength from tubes, filled with active mass in which a lead spine serves as a conductor.

In this design mechanical strength and electrical conductivity are separated, in contrast to the grid plate which has to do both: support the active mass and conduct electricity to the terminals. A positive tubular plate consists of a number of spines, connected to a top bar like a fork.

Tubular batteries are very popular in Europe and Japan because of the excellent performance in stationary and traction applications. In English they are referred to as Ironclad batteries, and in German Panzerplatte (abbreviated Pz). Tubular plates can have 19 spines (DIN) or 14 spines (Brittish Standard.