Energy density diagram comparing batteries including Lead Acid (LABs), Lithium-ion (LIBs) and Li-S or Lithium Sulfer (LSBs) in watt-hour per kilogram (Wh/kg) and watt-hour per litre (Wh/l). LSBs are projected to be superior. (Diagram courtesy Oxis Energy)
In late May 2015 “S” and I discussed Lithium Sulphur Batteries (LSBs) in the Comments section.
Currently diesel-electric operate using Lead-acid Batteries (LABs). From the 2020s some new-build submarines (including Soryu Mark 2s (28SS) will be utilising Lithium-ionBatteries (LIBs). If HDW 216 or Conventional Barracuda are ever built Australia is probably expecting them to have LIBs.
So Japan has decided to adopt LIBs for the next batch of Soryus the “Mark 2s” (first named here on November 5, 2014 :-). LSBs are intended to have a higher energy density than LIBs or, of course, LABs. However the reliability and safety of all battery types in submarines are essential traits. S advises that GS Yuasa Corporation will be the LIBs supplier for the Soryu Mark 2 which will deliver the LIB sample by 2020. I think this may delay the launch of the first Soryu Mark 2 (28SS) until 2021?
So LIBs may be the new in-operation batteries for submarine from the 2020s while LSBs may be the next advance in batteries for use from the 2030s.
Submarine generational turnover is less a problem in subs for the Japanese Navy (continuous build, one per year with 20 year operating life) than it is in the Australian Navy (non-continuous build, batches of 6 to 12? 30 year operating life).
For Australia it will be a major issue whether retrofitting LSBs in subs already fitted with LIBs will be a practical option. If a sub's whole electrical system (wiring etc) needs to be upgraded then LSBs might need to await the next generation of new-build submarines (2050s on). Australia may be more interested in nuclear propulsion by that time.
If upgrading with LSBs in the 2040s? after 15 years? is considered advantageous by Australia this may perhaps be done during "deep maintenance" when the hull is cut anyway - to replace major engine components.
Probably no-one knows how many years LIBs for submarine will remain efficient. Hence decisions on LSB replacement are far in the future.
Several companies worldwide are researching-developing LSBs. This includes UK company Oxis Energy Ltd. Oxis has provided the diagram above and the description below http://www.oxisenergy.com/technology/ which explains:
"Sulfur represents a natural cathode partner for metallic Li and, in contrast with conventional lithium-ion cells, the chemicals processes include dissolution from the anode surface during discharge and reverse lithium plating to the anode while charging. As a consequence, Lithium-Sulfur allows for a theoretical specific energy in excess of 2700Wh/kg, which is nearly 5 times higher than that of Li-ion.
Oxis’s next generation lithium technology platform offers the highest energy density among lithium chemistry:
- 300 Wh/kg achieved at cell level in 2014
- 400 Wh/kg forecast in 2016
Oxis patented chemistry provides inherent safety allowing it to meet international standards concerning shock, crush, thermal stability and short circuit...Thanks to its two key mechanisms, a ceramic lithium sulfide passivation layer and a non-flammable electrolyte, our cells can withstand extreme abuse situations such as bullet and nail penetrations with no adverse reaction."
Naturally companies need to sell their product and many details need to be worked out with new technologies.
For submarine use batteries need to be very safe (under normal and abnormal conditions) and reliable. Other issues under Australia mission conditions are their:
- charge speed to minimise indiscretion
- rate of self-discharging
- memory effect
- propensity to surge
- discharge rates (speed, volume, percentage)
- cycle life and operational life
- degree of maintenance needed
It would be interesting which German, French and US companies are developing LSBs?