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Electronics => Projects, Designs, and Technical Stuff => Topic started by: m3vuv on April 16, 2021, 01:58:05 pm

Title: modern dieselelectric subs
Post by: m3vuv on April 16, 2021, 01:58:05 pm
just wondered if they now use lead acid cells now or lithium ion?
Title: Re: modern dieselelectric subs
Post by: penfold on April 16, 2021, 03:10:59 pm
It's an interesting question. For military applications, I believe the answer may be considered a secret since it has implications on the performance and range of a sub. There are definitely manufacturers of li-ion submarine batteries and with fewer exemptions from RoHS etc for military applications, increases in performance and safety of li-ion, there are fewer reasons to go lead-acid. I believe the Japanese have announced the use of li-ion in some subs.

The submarine "industry" closer to home is however very, very conservative and the programme life can be upward of 80 years which puts constraints on the availability of supply, dependency on other nations that produce sufficient quantities of lithium and a need to stockpile spares, all of which make lead-acid more favourable. I would imagine that there is a certain amount of flexibility designed into the system for both diesel-electric and nuclear subs such that some of the risks can be mitigated and an alternative battery technology be changed in during the 10- or 20-year refits.

Hope that's something to go on, but I don't think it's an exclusive yes or no answer across the board.
Title: Re: modern dieselelectric subs
Post by: ledtester on April 16, 2021, 05:03:31 pm
Maybe lithium-ion:

https://www.theguardian.com/world/2019/jul/23/russia-submersible-fire-faulty-battery-may-be-cause-reports (https://www.theguardian.com/world/2019/jul/23/russia-submersible-fire-faulty-battery-may-be-cause-reports)

Quote
A malfunctioning lithium-ion battery may have sparked a deadly fire on a top-secret Russian nuclear submersible earlier this month that killed 14 naval officers, according to reports.
...
The submersible was equipped with a lithium-ion battery made in Russia to replace older, proven batteries procured from the Ukrainian defence industry.
...

Another article (2018) about the Japanese using Li-ion for one of their subs:

https://www.lithium-battery-factory.com/submarine-lithium-batteries/ (https://www.lithium-battery-factory.com/submarine-lithium-batteries/)

One issue mentioned is dissipating the extra heat given off by Li-ion batteries.
Title: Re: modern dieselelectric subs
Post by: bsdphk on April 16, 2021, 05:28:19 pm
Funny story...

Some Countryâ„¢ tried refurbish their submarine's lead-acid's with LiON, without doing the math, and not only was it no longer a submarine, it nearly capsized in the dock.

Since then refurbishing to LiON has in at least one case been done by keeping the bottom-most layer of batteries as lead-acid, but it will depend entirely on the design if that is possible.

New designs all seem to be LiON, and for a good reason: Less hydrogen.