Wednesday, June 8, 2011

Have they thought this one through?


I note that designers are considering the use of lithium-ion batteries in submarines. Ares reports:

The technology is ready for application, lithium-ion batteries increase endurance of the submarine from 50% to 400%, they cut the indiscretion rate by 20%, they allow maximum speed whatever the charge, they are totally maintenance free and they allow for maintenance cycles to be stretched to every 10 or 15 years. So says Manfred Klein, senior vice president, project development and R&D at Howaldtswerke-Deutsche Werft (HDW).


There's more at the link.

All that may be true . . . but there's one problem. Submarines sail in water. Lots of water. Furthermore, whilst their hulls are (hopefully) designed to keep the stuff on the outside, there are any number of ways that water can get inside - stormy seas may break over the conning-tower while the boat is running on the surface, the snorkel seal may develop a fault, and enemy weapons such as depth-charges, torpedoes or mines may explode nearby and produce leaks in the hull.

Any and all of those events are contra-indicated when a submarine has lithium aboard - because this is what happens when lithium encounters water.







Are we still sure that putting lithium-ion batteries inside a submarine, surrounded by water, is really such a good idea?





Peter
at

9 comments:

  1. Wayne ConradJune 9, 2011 at 12:11 AM

    Don't lead acid batteries also react to sea water? I thought they emitted chlorine gas, but I could be wrong.

    So maybe it's not which batteries are safe to have in a tube under the water. It's which are less dangerous.

    ReplyDelete
  2. Bill N.June 9, 2011 at 3:35 AM

    I think it is a great idea to install Lithium batteries in submarines. In fact I think we should help countries like Iran install them in their submarines :-)))

    ReplyDelete
  3. The Raving ProphetJune 9, 2011 at 9:53 AM

    I'd think there would be ways to keep them dry. If water covers them with quite enough pressure to penetrate a properly designed enclosure, then you've already experienced a loss of vessel event.

    We have Li-Ion batteries in numerous places where they might come in contact with water; I note that there's not a spate of phone explosions every time somebody gets rained on.

    ReplyDelete
  4. AnonymousJune 9, 2011 at 2:48 PM

    Lithium batteries have been used in implantable devices for heart issues (pacemakers and ICDs) for years - no issues with water. And the human body has a LOT of water in it. Not to say that there aren't any issues with batteries in implantable devices. You really don't want to short out a battery if it is in a person (see the last picture in the post)

    http://cardiobrief.org/2010/10/09/the-plot-thickens-in-the-case-of-the-exploding-icd/

    ReplyDelete
  5. MogrithJune 9, 2011 at 3:03 PM

    Lead acid Batteries do give off chlorine gas if exposed to seawater.

    At one time the US Navy had Subs that used Sodium as the primary coolant.

    Seawater in the people tank is always a bad thing but I think the advantages outweigh the problems.

    ReplyDelete
  6. CargosquidJune 9, 2011 at 3:25 PM

    Of course the fire could keep them all nice and warm when the cold water hits.... ;)

    ReplyDelete
  7. KurtPJune 9, 2011 at 11:12 PM

    Li batteries are sealed, regular acid batteries are not.
    As mentioned earlier sea water and HCL don't make good air.

    But- hey! why bother with that when America can do Nuke

    ReplyDelete
  8. Gay_CynicJune 10, 2011 at 1:17 AM

    Meh.

    I do batteries as part of work - powering electric vehicles. I'm not an engineer, but I know my way around a bit.

    First off, despite the original media copy, I rather doubt that anyone is putting 1st Gen Lithium Ion in anything anymore...due to its tendency to spontaneously combust. Current Gen (civ) is Lithium Ferrous Phosphide (aka LiPo) ..notably less flammable, and in combination with todays modern battery management the opportunity for mishap is notably reduced. The cutting edge stuff, Lithium Polymer, is still a year or two out (from what I hear) but will further improve the mass>power ratio by a significant percentage.

    Another reader notes that Lithium cells are sealed. Yep. They are. But if you don't have a decent battery management and charging set-up, they may not stay that way. Probably will, but...much better to do it right.

    Moving briefly along, there are a bunch of lead-acid technologies (both sealed and unsealed)...leaping easily to mind are flooded, AGM, and Gel batteries...each with their own comparably depressing characteristics.

    The advantage of Lith Packs are dramatically reduced weight, improved energy density, and substantially greater battery life.

    Best,

    GC

    ReplyDelete
  9. AnonymousJune 10, 2011 at 7:40 AM

    Lithium batteries were tried in a mini sub for SEALS. It burnt for six hours.
    http://en.wikipedia.org/wiki/Advanced_SEAL_Delivery_System

    ReplyDelete

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