World naval development October 2018
By Norman Friedman*
https://navalinstitute.com.au/possibilities-for-new-submarine-technology-on-show/
Possibilities for new submarine technology on show
"SMX 31 is an all-electric submarine, exploiting the increased energy density of lithium-ion batteries. They already dominate the commercial electronics market and are widely used elsewhere. Their energy density is far greater than that of conventional lead-acid batteries. The Japanese are installing them on board a new submarine (Oryu) and abandoning their current air-independent propulsion by Stirling engine. Reportedly these batteries will give the submarine eight day endurance at low speed (they may triple endurance at high speed). Their great advantage over Stirling and other air-independent powerplants is that they can be recharged by the submarine’s diesels. All other AIP powerplants require special oxidants, the capacity of which limits total AIP endurance. Too, eliminating a separate AIP plant would considerably simplify submarine design and operation, and it might also reduce vulnerability to shock. At least in theory it should considerably improve reliability. Reportedly other submarine manufacturers are considering taking the same step away from separate AIP powerplants."
The French concept submarine takes this a step further. Its lithium batteries would presumably be charged before it left port; Naval Group claims that SMX 31 would have a 30 to 45 day endurance, presumably at low speed (maximum speed would be about 20 kts). "
