The separator, which is the component that sends hydrogen to the fuel cell, was developed in cooperation with Kansai Paint Co. (TSE:4613). Dai Nippon's device consists of aluminum on which a resin film has been electrodeposited. The resin increases the separator's corrosion resistance to the same level as resin-coated stainless steel or gold-plated separators, overcoming aluminum's major weakness.

A separator features minuscule surface grooves that are 0.8 to 1mm wide and 0.3 to 0.8mm deep, so coating these grooves uniformly with resin was difficult. Dai Nippon accomplished this by preparing the aluminum's surface to facilitate electrodeposition and by altering the post-deposition heat treatment.

The aluminum separator is expected to cost half as much to produce as the stainless steel versions. 

(Nikkei)