F1technical.net

Are there any automated component disconnects triggered by an accident?

Do the lithium batteries present major fire hazard?

Brian

Unless the Lithium-Ion Batteries overheat, or are exposed to open flames it shouldn't be a fire hazard. I would assume that there would be some kind of fail-safe to disconnect the batteries from discharging accidentally during a crash.

hardingfv32 wrote:Are there any automated component disconnects triggered by an accident?

Do the lithium batteries present major fire hazard?

Brian

If they short they will over current and can catch fire. About the only way to put them out is to bury them in sand and let the reaction finish.

... or you could use sodium chloride. That is, salt.

That's what's inside many class D extinguishers, for metal fires (sodium, potassium, lithium).

The salt forms a crust that blocks the fire.

We do lomo a la sal (sirloin salted style) down here using the same method but without the batteries.

Ciro Pabón wrote:... or you could use sodium chloride. That is, salt.

That's what's inside many class D extinguishers, for metal fires (sodium, potassium, lithium).

The salt forms a crust that blocks the fire.

We do lomo a la sal (sirloin salted style) down here, but without the batteries.

some races recommend a copper dust fire extinguisher for LIpol fires but the battery data sheets say to use nothing but sand at least for LG chems and Kokams

Well, the difference is that copper dust clings to vertical surfaces, but salt is pretty effective with metals (sodium and potassium also).

The problem with lithium is that it flows, so salt cannot contain it sometimes. Silica also forms a crust but its melting point is higher (which is good).

I think that the battery sheet wants people not to pour water on the fire (which would be catastrophic) or to use regular extinguishers.

Anyway, do not carry your laptop while you race. If you crash and the car disintegrates and the carbon fiber is all over the track and you're bleeding and blind and crying, the batteries might explode. That could be dangerous.

Ciro Pabón wrote:Anyway, do not carry your laptop while you race. If you crash and the car disintegrates and the carbon fiber is all over the track and you're bleeding and blind and crying, the batteries might explode. That could be dangerous.

=D> =D> =D>

hardingfv32 wrote:Are there any automated component disconnects triggered by an accident?

Do the lithium batteries present major fire hazard?

Brian

Yes, litium ion batteries can both burn and explode. But some litium ion battery types are safer than others. There is not one type of lithium ion batteries but several. Usually they are separated based on cathode material, for instance: LiCoO2, LiFePO4 and LNC (lithium nickel cobalt) like NCA (nickel cobalt aluminum). Some lithium ion batteries are designed for high energy density and low power density and others for a high power density and a low energy density. For KERS the latter is used. I think SAFT base their KERS batteries on the VLV range, which is a NCA type of lithium ion battery:

http://www.saftbatteries.com/Produit_La ... fault.aspx

I know the other lithium chemistries are safer overcharging temps, but once in a fire would there be much difference?

Brian

A123 used by Merc use LiFePO4 AFAIK and they are not so dangerous as other types.

http://en.wikipedia.org/wiki/Lithium_iron_phosphate

The battery manufactures are talking about charging and discharging safety issues, not about being part of a car fire that might be of their causing.

Brian

WhiteBlue wrote:A123 used by Merc use LiFePO4 AFAIK and they are not so dangerous as other types.

http://en.wikipedia.org/wiki/Lithium_iron_phosphate

I actually just built a battery for my bike out of these. They don't require special protections circuits either.