First All-Electric Ferry Thermal Run Away 1

[TugboatEng]

https://gcaptain.com/battery-powered-brim-declared-safe-after-overheating-in-norway/

Not quite a disaster, more of a near miss but there is much to learn here. Manufactures of Lithium batteries have gone to great lengths to keep them from catching on fire. Instead, they release explosive and toxic gasses. You'd think there would be some consideration for ventilating the space after such an incident?

https://www.mdpi.com/2313-0105/2/1/5/htm

 

[1503-44]

If there is no design standard issued on it yet, I can assure you that few will think about venting explosive gases, or anything else, until after they blow up. Hurry up and get that design standard issued.

 

[EdStainless]

So what are the requirements for venting and fire suppression in the battery spaces?
I can't believe that insurance companies don't care.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[stevenal]

You wish to ventilate the space after thermal runaway has begun? I think you'd want to do just the opposite to deprive the fire of oxygen. Let's close the vents and flood the compartment with inert gas or an extinguishing agent. Ventilation of battery compartments is part of the Coast Guard requirements. Perhaps better standards are needed for electric craft, though.

 

[TugboatEng]

New standards are certainly needed. A staged system that first inerts the atmosphere and then ventilates it after things cool off. Then again, the neighbors might not be too happy about a discharge of hydrogen fluoride.

From the second article, it seems the worst case is when the battery doesn't burn as those nasty chemicals don't get oxidized.

"As the case of a burning cell must be strictly avoided because of the cascaded inflammation of neighboring cells, which is most likely to occur, the first security measure is to suppress the inflammation of the emission gases, thus drastically reducing the amount of energy released. This was achieved by using a textile composite material enclosing the cell and thereby prohibiting flying sparks while being permeable for the emission gases [16]. For this case (Scenario 2), almost no oxidation takes place. Consequently, a larger amount and a respective higher quantity of unburned organic substances were expected and could be verified by the analytical methods."

 

[EdStainless]

I am with TBE, I can see initial inerting, followed by a purge/vent. Scrubbing this vent gas isn't that hard, or use a combustor in the vent line.
Yes, there are two issues here, the reaction products from the fire, and the risk of setting off other cells.
I would think that for shipboard use packaging density isn't as critical and better isolation may be warranted.


= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[FacEngrPE]

Loyds is looking at the issue,

https://www.lr.org/en/latest-news/lr-issues-new-guidance-on-large-battery-installations/

The document is thin on detail.

 

[TugboatEng]

I just saw that they ferry is 24m long which is a class beater size. Vessels under 24m (79 feet) are not required to have a load line so they aren't under the rules of a class society like Loyd Register. I know because I have 6 vessels that are conveniently 78 feet long. Then again, none of this matters if the vessel doesn't sail on oceans.

I am unsure of Norway's rules but I'm sure they're similar to USA. The vessel is large enough that it's machinery spaces should be protected by a fixed fire fighting system so that base is already covered. Heptafluoropropane is the current flavor of clean extinguishing agents.

 

[Sparweb]

This is a tough problem, and it isn't close to being solved yet.
Lithium batteries can get into a runaway situation, release a lot of heat very fast, plus all these nasty gases. Once they start going, there's not much you can do to stop it.

I think the most effective fire protection will be in the design and manufacture of the cells themselves (not the suppression systems). Unfortunately, most of them are manufactured in Asia, at low cost, and the typical purchaser is not enforcing a quality standard before they buy. Applications like the ones below that actually make the news will at least have some safety standard to live up to, but as you can see in the Boeing case, even they are still learning. There are some aviation-related standards, but they are mostly test standards, not design standards. By that, I mean that there aren't safety rules to follow in the design or fabrication of the batteries. Rather, batteries that pass a test one way or another are the ones that meet a standard. There's a logic to that, and it's quite rigorous, but it doesn't lead to lessons that get shared industry-wide as "best practices". Instead it leads to companies discovering tricks that work, each of them in their own proprietary way.

Utility Battery Fire in Arizona:

https://www.eng-tips.com/viewthread.cfm?qid=476108

Union Pacific rail yard in North Platte - Tesla Fire:

https://www.eng-tips.com/viewthread.cfm?qid=472150

Boeing 787 Lithium Battery incidents, 2013:

https://simpleflying.com/boeing-787-battery-problems-overcome/

Please remember: we're not all rednecks!

http://www.sparweb.ca

 

[TugboatEng]

This is our sister company:

https://www.google.com/url?sa=t&sou...Vaw21LzHnt34hxT0MO4oYUkSB&cshid=1616129738395

I wish I had more information. I do know that they were not able to release the fixed firefighting system because the pull handles were located by the engine room ventilation louvers and the heat coming out was too intense.

Edit: I found a non-news article which better explains things.

 

[Comcokid]

SparWeb. All of the incidents you list were Lithium Ion Cobalt batteries. On the plus side, they are the least expensive and have the highest energy density. On the down side, they fail spectacularly.

For higher cost and slightly less energy density there is Lithium iron phosphate (LiFePO4) batteries. Failure modes are much, much more benign. The first batteries approved under the new aircraft RTCA DO-311 standards that came about after the Boeing issues are LiFePO4 chemistry.

 

[Sparweb]

Thanks for pointing that out! Along the lines of what I was thinking as I wrote my last post, but didn't follow through on the point, that there already ARE distinctions that make a significant difference.

DO-311 is the kind of standard that I was referring to. I also refer to this:

FAA Advisory Circular 20-184 - Guidance on Testing and Installation of Rechargeable Lithium Battery and Battery Systems on Aircraft

This is the current state of design guidance in aviation:

Health Monitoring.
Lithium batteries should be stored in accordance with the manufacturer's recommendations for state of charge and temperature; consideration should be provided for any monitoring circuitry that may drain the battery during the storage period. Additionally, overcharging of individual cells could lead to thermal runaway. Health monitoring of lithium batteries needs to be taken into account during testing and certification to ensure that proper state of charge can be maintained.

Flammability.
Aircraft batteries must meet the applicable flammability requirements of §§ 23/25/27/29.853, 23/25/27/29.863, and 25.869 that ensure the protection of structure and critical systems. Test the materials to ensure they meet applicable requirements of §§ 23/25/27/29.853, 23/25/27/29.863, and 25.869.
The FAA Aircraft Materials Fire Test Handbook, DOT/FAA/AR-00/12, describes an acceptable means of compliance with 14 CFR part 25, Appendix F. If thermal and acoustic insulation material is used as part of the battery equipment and exposed, the requirements of § 25.856(a), Appendix F, part VI, at amendment 25-111 (or later amendment) must be met. Refer to the test methods described by AC 25.856-1, Thermal/Acoustic Insulation Flame Propagation Test Method Details.

This is the current design approach: Testing, and health monitoring. Material specifications are not explicitly defined. Chemistry is not mentioned. You can read that AC and have no idea that different chemistries can have a drastic effect on the outcome of an over-charge or thermal runaway.


Please remember: we're not all rednecks!

http://www.sparweb.ca

 

[Comcokid]

The FAA Advisory Circular 20-184 is interesting. Especially the statement "Lithium batteries should be stored in accordance with the manufacturer's recommendations for state of charge...". Lithium chemistries don't like deep discharge. They do best in storage if kept in a 40 to 70% charge state.

The Nippon Airways 787 emergency landing at Takamatsu Airport on Jan 16, 2013 may be part of the reason for this statement. From what I understand the maintenance personnel had been regularly deep-discharging, then recharging the lithium batteries. Basically following the discharge/recharge approach used by some for Nickel Cadmium chemistries to address the charge memory effect.