soviet use of Silver Zinc batteries

[msxyz]

Does anybody have some reliable info (specs, measurements, construcion data) on the soviet built silver zinc accumulators for submarine use?

At least two class of subs used them (Juliett, Alpha) as they offer more than twice the energy density per weight unit than conventional lead acid batteries.

While the higher specific energy content is desireable, silver zinc batteries have some serious drawbacks, especially for use in a sub.

First, they have a short 'wet life' meaning that once filled with the caustic electrolyte, they degrade over time: until recently, their life expectancy was about 30 months. In a sub, that would mean, every two years or so, to place the boat into a drydock, open a maintenance hatch and move around (mostly by hand crank) huge boxes weighting half a ton: what fun!

Then, there is also the problem of having their performance degrade significantly after a few recharge cycles because silver and zinc dissolve and migrate from their respective plates. Some addictives can reduce this phenomenon but their useful life was, until recently limited to less than a hundred cycles.

Before the advent of lithium cells, the technology had made some advances such as using iron instead of zinc (no dendrite formation and better tolerance to rough use) and using sandwitched layers of grafted polypropylene and cellophane as ionic membrane (better corrosion resistance, stops migration of silver iones) but these advances were made, as far as I'm aware, only in the last decade of the XX century.

Today silver zinc has disappeared in all but missiles/torpedoes where cost and long operational life are secondary concerns as they allow higher discahrge currents than Lithium accumulators. Just before use, you pop a cap, drop the electrolyte into the battery and you're ready to go.

Back to my original question, I'd like to know if anybody has a better insight of the silver zinc accumulator research in the Soviet Union. There might be some info or pictures around the net but not in english so search engine returned little results so I'm seeking assistance from russian submariners, if any of them sails in these waters All I could gather is that the batteries inside the Juliett were called 'type 30/3' weighted some 500 kg and had a capacity of 30000 Ah. Oh and apparently they were also water cooled because during fast dischargs/recharges they got pretty hot (although I don't know how reliable is this last info... )