Japan Military News, Reports, Data, etc.

Stealthflanker said:

They are but is the cause of the fire because the battery being a Lithium Ion in the first place ?

The battery wont spontanteneously combust by itself, not without something else causing it. maybe overcharging, overheating or some design defects ? Who knows.

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You're right. But the point is lithium ion batteries are too unstable. Look at the BYD blade battery (lithium iron phosphate), it did not burst into flames even when punctured.
I wouldn't include such a technology in any military vessel where the use conditions make the risks outweight the benefits, and submarines are a waaaayyyy riskier environment than even that.

Virtup said:

You're right. But the point is lithium ion batteries are too unstable. Look at the BYD blade battery (lithium iron phosphate), it did not burst into flames even when punctured.

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Every accident should be looked upon in individual basis before trying to establish a correlation. Just because automotive or cellphone Li-Ion burst into flames you cannot just correlate it with submarine battery. Even if they do combust one have to investigate what is the cause of such.

Virtup said:

I wouldn't include such a technology in any military vessel where the use conditions make the risks outweight the benefits, and submarines are a waaaayyyy riskier environment than even that.

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Yeah if same logic applied to fuel cell or any Electrochemical generator AIP in that respect.. Nobody would want to have combustible Liquid oxygen onboard submarine as the tank requires insulation, cryogenic facilites to produce the oxygen and some treatment to ensure safety of the operation.

Stealthflanker said:

Every accident should be looked upon in individual basis before trying to establish a correlation. Just because automotive or cellphone Li-Ion burst into flames you cannot just correlate it with submarine battery. Even if they do combust one have to investigate what is the cause of such.



Yeah if same logic applied to fuel cell or any Electrochemical generator AIP in that respect.. Nobody would want to have combustible Liquid oxygen onboard submarine as the tank requires insulation, cryogenic facilites to produce the oxygen and some treatment to ensure safety of the operation.

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There was another case of the batteries combusting onboars the Boeing 787, which should have similar or close to similar safety requirements to submarines.

The biggest problem with batteries when it comes to fires, is that while you can isolate oxygen or fuel in a normal fire incident, you can't do that with battery cells since they contain the entire fire triangle internally. That's why you can only resort to cooling them with large quantities of water to try to slow down the spreading of the flames. This saves lives in car crashes, and could potentially allow submarine crews to evacuate and seal the affected compartment, but you will most likely lose that compartement to the fire. Other extinguishing solutions do exist but they rarely work (Losharik must have had them or russian engineers are very dumb).

What I'm trying to say is, by sacrificing a bit of energy density (LiPO batteries), you make the submarine way more resilient to accidents (shockwaves, collisions, electrical failures, etc). why wouldn't naval engineers take such a trade? they were fine with lead acid batteries. I don't understand.

Stealthflanker said:

Well 20-25% of surface displacement of a conventional submarine is Battery so the Japanese's sub has over 700 metric tonne of Li-Ion battery inside.



Is this really the battery's vault ?

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Yes it is.

Stealthflanker said:

They are but is the cause of the fire because the battery being a Lithium Ion in the first place ?

The battery wont spontanteneously combust by itself, not without something else causing it. maybe overcharging, overheating or some design defects ? Who knows.

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Yes it is. And yes it will. You absolutely do not need overcharging, overheating, or design defects. There is an inherent % of failure during the manufacturing and quality control inspection processes. Air and sea shipping can trigger a delayed failure as well via air pressure and ambient temperature changes. Sometimes that leads to fires in the warehouse or on route.

For purposes of use in mission-critical/military projects, I am distinguishing between lithium iron phosphate (the most expensive but most stable and safe of all) and the rest of the lithium ion battery chemistries (all varying degrees along a spectrum of unsafe, unstable, but an order of magnitude cheaper). I am all but certain they went with one of the latter choices. The former is simply impossible to source in the formats you need unless you are going to have massive production runs like Tesla (or the Chinese mil-ind complex). Also, batteries will and often do spontaneously combust if the manufacturing process or quality control are subpar. And also if the manufacturing run was geared towards cost and volume rather than quality and reliability. That's why buckets of water are kept around near production lines so that slightly defective products that begin hissing/swelling get dumped right away. It literally happens every day on the production line, and in warehouses too.

If you ever need a quick rule of thumb: Lithium Polymer = stay away and do not use in your products unless you don't care about brand building and customer safety. That's usually used by suppliers as an industry term to mask that they're using one of the least safe and least stable battery chemistries. Even if you ask them what's the actual battery chemistry they use, many will deflect, lie, or refuse to tell you.

CMP said:

Also, batteries will and often do spontaneously combust if the manufacturing process or quality control are subpar. And also if the manufacturing run was geared towards cost and volume rather than quality and reliability. That's why buckets of water are kept around near production lines so that slightly defective products that begin hissing/swelling get dumped right away. It literally happens every day on the production line, and in warehouses too (air and sea shipping can trigger more defects leading to spontaneous combustion in a warehouse further down the line).

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Why we arent hearing fire incident on Japanese sub yet ? They are using Lithium-Nickel type. Or the Japanese do know how to make safe Li-Ion battery ?

Virtup said:

There was another case of the batteries combusting onboars the Boeing 787, which should have similar or close to similar safety requirements to submarines.

The biggest problem with batteries when it comes to fires, is that while you can isolate oxygen or fuel in a normal fire incident, you can't do that with battery cells since they contain the entire fire triangle internally. That's why you can only resort to cooling them with large quantities of water to try to slow down the spreading of the flames. This saves lives in car crashes, and could potentially allow submarine crews to evacuate and seal the affected compartment, but you will most likely lose that compartement to the fire. Other extinguishing solutions do exist but they rarely work (Losharik must have had them or russian engineers are very dumb)

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Is the current Japanese submarine battery is of the same design as Russian one ?

Virtup said:

What I'm trying to say is, by sacrificing a bit of energy density (LiPO batteries), you make the submarine way more resilient to accidents (shockwaves, collisions, electrical failures, etc). why wouldn't naval engineers take such a trade? they were fine with lead acid batteries. I don't understand.

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and what the Japanese do Know how to make safe submarine Li-Ion battery ? Is that impossible ?

Stealthflanker said:

Why we arent hearing fire incident on Japanese sub yet ? They are using Lithium-Nickel type. Or the Japanese do know how to make safe Li-Ion battery ?



Is the current Japanese submarine battery is of the same design as Russian one ?



and what the Japanese do Know how to make safe submarine Li-Ion battery ? Is that impossible ?

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The failure is a % of the total produced. If the Japanese build a larger number of submarines, you'll start seeing some fires here and there. This is all basic Six Sigma stuff. If you're having trouble grasping the dynamics at play here, just imagine it's fire gacha and you'll somewhat get it.

It's not impossible for developed countries to jump into this in a big way, but it's very costly and "dirty" (lots of chemical waste output from rejects off the production line). There's a reason why mass production of lithium ion batteries mostly happens in China but not the US/Japan (they mostly source from Chinese factories). I speak of this from a nearly decade-long experience in this field, cutting across both the business and the technical side. A lot of money in the West has already been dumped into efforts like this, and it has been a pretty huge waste (no profits to be had). i.e. invest 100 million USD and produce maybe 1-10 million dollars worth of good high quality batteries over a 5 year period. The vast majority of output will be low quality crap that you need to pay a lot of money even to get rid of it (as hazardous chemical waste).

Virtup said:

There was another case of the batteries combusting onboars the Boeing 787, which should have similar or close to similar safety requirements to submarines.

The biggest problem with batteries when it comes to fires, is that while you can isolate oxygen or fuel in a normal fire incident, you can't do that with battery cells since they contain the entire fire triangle internally. That's why you can only resort to cooling them with large quantities of water to try to slow down the spreading of the flames. This saves lives in car crashes, and could potentially allow submarine crews to evacuate and seal the affected compartment, but you will most likely lose that compartement to the fire. Other extinguishing solutions do exist but they rarely work (Losharik must have had them or russian engineers are very dumb).

What I'm trying to say is, by sacrificing a bit of energy density (LiPO batteries), you make the submarine way more resilient to accidents (shockwaves, collisions, electrical failures, etc). why wouldn't naval engineers take such a trade? they were fine with lead acid batteries. I don't understand.

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If you seal a lithium battery compartment, the oxygen in the air will rapidly be used up by any fire.
But the heat will continue to be released into the compartment as part of the battery thermal runaway.
And with no way to remove the heat, the temperature could exceed the melting point of the steel floor.

AndrewS said:

If you seal a lithium battery compartment, the oxygen in the air will rapidly be used up by any fire.
But the heat will continue to be released into the compartment as part of the battery thermal runaway.
And with no way to remove the heat, the temperature could exceed the melting point of the steel floor.

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Can the battery be cooled enough with ventilation or refrigeration?

broadsword said:

Can the battery be cooled enough with ventilation or refrigeration?

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There would have to be some means of cooling or heat transfer anyway with normal operation.

But in a thermal runaway event?

AndrewS said:

There would have to be some means of cooling or heat transfer anyway with normal operation.

But in a thermal runaway event?

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Agreed. If thermal runaway begins, nothing is going to stop it short of dumping the entire thing into a tank of water. And at that point, you've just lost your entire battery pack anyways. One way around this is to use a large number of smaller battery packs distributed throughout the submarine, with automated systems for jettisoning them into a water tank. When the thermocouple reads beyond the threshold, the system can go ahead and do its thing. You'd lose some of your total capacity but preserve the rest.