Soryus on Lithium-ion Batteries an Evolution Not Revolution

The following is mainly drawn from discussions between "S" and Pete on the Comments thread for Air Independent Propulsion (AIP) Issues of April 23, 2015. A big thankyou to S for doing the estimates and providing other comments. 

Reuters reported November 19, 2014 that Australia wants its future submarines to use Lithium-ion batteries (LIBs) and no AIP. 

S advises that originally Stirling AIP was unpopular in the Japanese Navy, because of its low power (2.5knots) and complicated operation. For Japan AIP was only a temporary measure on the Soryu until Lithium-ion batteries (LIBs) became a more mature technology.

Looking at the Table at the bottom of this article you will see the first tranch (Mark 1) of what may eventually be up to 12 Soryu submarines are known as “16SS” in red. 16 is the last two digits of the Soryu’s first of class’s “Building no. 8116” and “SS” means conventional submarine. The “Soryu” 16SS was commissioned in 2009. 16SS is diesel-electric with lead-acid batteries and Stirling AIP.

Published figures for 16SS range/speed (see sidebar of Wiki) would most likely be for semi-submerged snorkel/snorting mode. 16SS fully submerged (no snorkel use) figures are classified but S’s estimate for submerged speed and endurance is 6 knots for 3 days.

The aim of S's input is to give an estimate for the fully submerged range/speed of the second tranch Mark 2 Soryu’s further down the Table, known as 28SS in red. The first of class 28SS may be commissioned in 2022. It will not have AIP but instead will have new Lithium-ion batteries (LIBs).

As yardsticks for comparision are:

- the Collins submarine, has lead-acid batteries totalling 400 tonnes. Its submerged speed x duration = approximate range is 4 knots for 5 days = 480 nautical miles.

- while German submarine U-32's (a HDW 212A) 2013 test using an initial diesel engine charge  with lead-acid batteries then fuel-cell AIP charging the batteries achieving 6 knots for 20 days = 2,800 nautical miles.   

S estimates 28SS (using Lithium-ion Batteries) submerged speed x duration = approximate range will be 4 knots for 30 days = 2,900 nautical miles. 

S's calculations are on the Comments thread here.

PETE'S COMMENT

One must remember that the above are estimates based on several assumptions. It indicates that in terms of range LIB will be similar to AIP using lead-acid batteries. However using AIP and LIBs a sub would have a much longer range submerged performance. The safety-danger issue for AIP from fire is higly significant - so it and other LIB - AIP comparitive issues will be discussed in a future article.  Ultimately issues and comparisons will only be possible once Mark 2 Soryus (28SS) and HDW subs with AIP and LIBs come into service after 2022 or so.

Australia would want a transit speed (Fleet Base West, Rockingham, Western Australia to around Darwin and alternatively Rockingham to Sydney) of perhaps 12 knots. After that an Australian sub may rely on much more fully submerged LIB use in order to stay out of view of Chinese satellites (keeping away from Chinese undersea sensor arrays is another problem).

Variables that are difficult to predict are whether the next tranche Mark 2 Soryus (28SS) is larger or smaller than 16SS or whether Japan may build an Australia-only version.

LIBs and/or AIP still will not compare to the performance of nuclear propulsion. 

Two useful two web documents are:

-  http://en.wikipedia.org/wiki/Drag_(physics) , “Drag at high velocity”“Power” (in fluid dynamics 6 knot/h is high velocity).

-  https://samueldavey.files.wordpress.com/2013/04/fluid-dynamics-submarine-report.pdf an Australian Maritime College paper of 30 pages. This is especially interesting. It draws on Australian Defence Science and Technology Organisation (DSTO) findings. It explains why submarines are shaped as they are and what modifications can make them move more efficiently.

For further information on LIB issues and other Soryu issues see many more articles on Submarine Matters, including:

Technical issues and the Soryu - Lithium-ion batteries no AIP  of February 12, 2015,

MHI and KHI not at Australia's Future Submarine Summit, Adelaide, March 24-26, 2015 of March 24, 2015, and

Air Independent Propulsion (AIP) Issues of April 23, 2015.

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Soryu 16SS can be called "Soryu Mark 1s" with Stirling AIP. Future Soryu 28SS can be called "Soryu Mark 2s" with no Stirling AIP but they will have Lithium-ion batteries (LIBs). 

SS No.	Building No.	Pennant No.	Name/Namesake	LAB or LIB & AIP *	Laid Down	Laun -ched	Commi-ssioned	Built By
16SS	8116	SS-501	Sōryū (そうりゅう) / Blue Dragon	LAB + AIP	March 2005	Dec 2007	March 2009	MHI
17SS	8117	SS-502	Unryū (うんりゅう) / Cloud Dragon	LAB + AIP	March 2006	Oct 2008	March 2010	KSC
18SS	8118	SS-503	Hakuryū (はくりゅう) / White Dragon	LAB + AIP	Feb 2007	Oct 2009	March 2011	MHI
19SS	8119	SS-504	Kenryū (けんりゅう) / Sword Dragon	LAB + AIP	March 2008	Nov 2010	March 2012	KSC
20SS	8120	SS-505	Zuiryu (けんりゅう) / Sword Dragon	LAB + AIP	March 2009	Oct 2011	March 2013	MHI
22SS	8122	SS-506	Kokuryū (こくりゅう) / Black Dragon	LAB + AIP	January 2011	Oct 2013	March 2014	KSC
23SS	8123	SS-507	Jinryū (じんりゅう)/ Benevolent Dragon	LAB + AIP	Feb 2012	Nov 2014	March 2016?	MHI
24SS	8124	SS-508	?	LAB + AIP	2013	2015?	2017	KSC
25SS	8125	SS-509	?	LAB + AIP	2014	2016?	2018	MHI
26SS	8126	SS-510	?	LAB + AIP	2015	2017?	2019	KSC
27SS	8127	SS-511	Soryu Mark 2	LIB only	2016?	2018?	2020?	MHI
28SS	8128	SS-512	?	LIB only	2017?	2019?	2021?	KSC
29SS	8129	SS-513	Next- Generation Submarine *	LIB only	2018?	2020?	2022?	MHI
			1st Australian class?

* LAB means Lead Acid Battery, LIB is Lithium-ion Battery, AIP is Air Independent Propulsion

29SS will be a new submarine class (no longer called Soryu). 

New features for the Next-Generation Submarine - 29SS - may include:

-  A more effective and powerful snorkel generation system for recharging the LIBs.

-  A next generation sonar system

-  Introduction of the Next-Generation heavyweight torpedo known as G-RX6.

-  An improved platform to reduce vibrations. This platform will be more impact resistant.

Again thankyou S for doing most of the work :)

Regards

Pete