Japan Military News, Reports, Data, etc.

T

taxiya

Brigadier
Registered Member
There is nothing to stop the other AIP subs to replace their lead-acid batteries with Li-on batteries. This is actually pointed out by the article in #2261.

Essentially all what the proposed Soryu class is doing is to exchange the bulk and weight of liquid oxygen tanks with extra Li-on batteries by loosing the capability of running totally submerged. It is a tactical choice, not much of a technological advance. The only technological advancement would be to reduce/eliminate the danger of Li-on battery to be lower than the danger of liquid-oxygen or/and liquid-hydrogen in case of fuel-cell.

As this thread is about Japan, I must make it clear that I am not bashing Japan's technology advancement. And I am aware that Japan is ahead of most countries in Li-on battery technology. What I am trying to say is that Japan's motivation of going this path has more to do with tactical consideration and maybe reducing reliance on foreign technology (politically and economically) than the supposed advantages proposed by the article.
 
SamuraiBlue

SamuraiBlue

Captain
taxiya said:
There is nothing to stop the other AIP subs to replace their lead-acid batteries with Li-on batteries. This is actually pointed out by the article in #2261.

Essentially all what the proposed Soryu class is doing is to exchange the bulk and weight of liquid oxygen tanks with extra Li-on batteries by loosing the capability of running totally submerged. It is a tactical choice, not much of a technological advance. The only technological advancement would be to reduce/eliminate the danger of Li-on battery to be lower than the danger of liquid-oxygen or/and liquid-hydrogen in case of fuel-cell.

As this thread is about Japan, I must make it clear that I am not bashing Japan's technology advancement. And I am aware that Japan is ahead of most countries in Li-on battery technology. What I am trying to say is that Japan's motivation of going this path has more to do with tactical consideration and maybe reducing reliance on foreign technology (politically and economically) than the supposed advantages proposed by the article.
Click to expand...

My take is that all technology has it's strong and weak points.
The reason why JMSDF is opting for Li Ion batteries and this has been mentioned by the brass, is because with conventional AIP system is that the sub's mission range is dictated by the amount of liquid oxygen supply they carry.
Although Li ion batteries require to snorkel, it fast re-charging characteristics makes it possible to fully recharge within few hours and not half a day.
 
Last edited:
Jura The idiot

Jura The idiot

General
Yesterday at 12:16 PM
Jura said:
continuation of the post right above
source:
Please, Log in or Register to view URLs content!

I didn't post the pictures from inside except
Click to expand...
related:
Japan leads way with Li-ion submarines
Japan's first submarine to be powered by lithium-ion (Li-ion) batteries will be commissioned in March 2020, doing away with lead-acid batteries and a Stirling air-independent propulsion (AIP) system.

With the arrival of this eleventh Soryu-class submarine the Japan Maritime Self-Defence Force (JMSDF) will be the world's first navy to field a conventional submarine powered by Li-ion batteries.

VAdm (Retired) Masao Kobayashi, former commander of the
Please, Log in or Register to view URLs content!
, explained at UDT Asia in Singapore on 18 January that the new type 'will change conventional submarine operations dramatically'.

While Li-ion batteries offered similar endurance to an AIP system combined with lead-acid batteries at low speeds, Kobayashi said their advantage was found in longer endurance at higher speeds (e.g. during an approach or evasion) thanks to their higher capacity.

Furthermore, Li-ion batteries can be recharged at sea by snorkelling, which Kobayashi described as 'revolutionary', when compared with an AIP system.

They also have a shorter indiscretion time due to a high charge current, whereas lead-acid batteries take a long time to restore their electrical capacity. Additionally, Li-ion batteries have a long life, are maintenance-free, enjoy simple operation and result in a simpler power structure.

Their biggest disadvantage is monetary, however. The first Li-ion-powered Soryu-class submarine will cost JPY64.4 billion ($566 million) as opposed to JPY 51.7 billion for the preceding boat in the class. Much of this $112 million difference is due to batteries and electrical circuits.

There are three requirements to fully exploit Li-ion batteries in any submarine. They require high-power diesel engines and a generator, bigger exhaust/intake pipes, alterations to electrical circuits (especially circuit breakers) and high-power diesel engines and a generator.

As Li-ion batteries are lighter than lead-acid batteries the Soryu platform had to be redesigned slightly to maintain weight/balance.

Two Li-ion types are available: lithium nickel cobalt aluminium oxide (NCA) manufactured by GS Yuasa; and lithium-titanate (LTO) from Toshiba. The JMSDF will use NCA-type batteries whereas Kobayashi believes LTO types were offered to Australia for its Future Submarine proposal.

The retired submarine commander believes that there is no clear single lithium-ion solution as a submarine main battery, so he predicted future submarines could optimise different power sources. For mobile operations, for example, NCA batteries and diesel is ideal, while an ambush submarine would operate better on fuel cells, LTO and diesel. The lowest-cost option would be LTO and diesel.

Japan's introduction of a submarine employing Li-ion batteries is the culmination of many years of research that commenced in 1962. The first Li-ion battery was ready in 1974 but it did not meet requirements.

Because fuel cell technology was not yet mature and the cost of Li-ion batteries was prohibitive, Japan turned to Stirling AIP systems. From 1991-97 AIP was used on a testbed before being installed into a Harushio-class submarine in 2000-01 for trials.

Meanwhile, tests on Li-ion batteries continued to the point that the JMSDF asked for a Li-ion-powered Soryu-class boat in its FY2015 budget request.
Click to expand...
source:
Please, Log in or Register to view URLs content!
 
Jura The idiot

Jura The idiot

General
SamuraiBlue said:
...
Although Li ion batteries require to snorkel, ...
Click to expand...
well I happen to know even the Czechoslovaks for some time
Please, Log in or Register to view URLs content!

flew with some high frequency radar to detect a snorkel

(this unit engaged 33 U-Boots, out if which five were sent down, and one damaged;
the connection to Japan would be the successful attack of the German steamboat Alsterufer bringing rubber from Japan to Germany)

I mean just everybody goes after snorkels
 
SamuraiBlue

SamuraiBlue

Captain
Jura said:
well I happen to know even the Czechoslovaks for some time
Please, Log in or Register to view URLs content!

flew with some high frequency radar to detect a snorkel

(this unit engaged 33 U-Boots, out if which five were sent down, and one damaged;
the connection to Japan would be the successful attack of the German steamboat Alsterufer bringing rubber from Japan to Germany)

I mean just everybody goes after snorkels
Click to expand...

I am aware that surface radar is able to pick up a snorkel BUT if the sub is up for just a couple of hours at a time instead of 6~8 hours needed to recharge conventional lead batteries then it makes it a lot harder to find.Also these days the snorkels are coated with radar absorbent paint so you'll need MPAs to come a lot closer for the sub to be spotted.

As for;
There is nothing to stop the other AIP subs to replace their lead-acid batteries with Li-on batteries.
Click to expand...
This actually doesn't work so well or JMSDF would have done it a long time ago. The problem is the sub's electrical system is all worked around the capacity of the batteries. It's like plugging in an electric appliance that is designed for 100V into a 200V industrial outlet, the appliance will be fried the moment you turn it on.
 
Last edited:
You must log in or register to reply here.
Top