Cadmium cellophane

The positive plates are siatered silver on a silver grid and the negative plates are fabricated from a mixture of cadmium oxide powder, silver powder, and a binder pressed onto a silver grid. The main separator is four or five layers of cellophane with one or two layers of woven nylon on the positive plate. The electrolyte is aqeous KOH, 50 wt %. In the aerospace appHcations, the plastic cases were encapsulated in epoxy resins. Most usehil cell sizes have ranged from 3 to 15 A-h, but small (0.1 A-h) and large (300 A-h) sizes have been evaluated. Energy densities of sealed batteries are 26-31 W-h/kg. 

In narrowly spaced vented nickel/cadmium batteries, cellophane occasionally is used as an ion-conducting foil to prevent direct gas flow between the electrodes. 

Although the cellophane replacement used for the gas barrier alleviates the above failure mechanism, it introduces another problem, if the cell is not manufactured and maintained properly. Without proper additives in the electrolyte, which find their way into the cadmium electrode during cycling, the cell can lose capacity in the negative electrode. The role of supplying an oxidized cellophane expander for the cadmium electrode needs to be replaced by cellulose derivatives and other additives to maintain the negative capacity."... 

---