Lipo Battery Box design

[countermeasure]

Hi.

So what is the current design thoughts on battery box? Primary objective is plan for LiPO fire. 2nd priority is weight consideration.

Wood? Plastic? Aluminum? Steel? Immerse in mineral oil like steveo suggests?

Let's assume LiPO fire is a certainty. How would you design it to minimize damage to surrounding material? Would install a fire suppression system be helpful?

EV traction pack is roughly 310 V, 12 AH. Using Turnigy nano-tech 6S, 5.8 mAH battery packs. Charged to 4.1 Vdc per cell. 4 packs paralleled first, and then connected in series.

Charge using Elcon bulk charger. Balance using RC battery charger every 10 cycles. Fire suppression is ABC fire extinguisher plumbed to battery. Manual activation.

 

[Pure]

It depends on the application. If it is meant for a car then about the best thing you can do is make a battery box that drops down and out of the car. A sealed metal box is a recipe for a bomb, and venting it would allow the flames to escape but would risk catching the car's interior on fire. Fire suppression with lithium is no easy task, as normal means of suppression are useless for anything other than preventing anything else from burning.

Now for a bike, sealed aluminum or steal boxes with vent holes that will point the flames away from the rider, and make sure when you park it, they are not pointed towards anything that can combust.

 

[CamLight]

IMHO, adding a fire suppression system isn't worth it. You need a Class D extinguisher anyway. A Class ABC extinguisher might help a bit but proper venting and, perhaps, dumping is by far your best bet....IMHO.

Lining the pack box with a high-temperature insulation material would be a good start for isolating the heat as the pack burns (and vents). Something like silica ceramic fiber or alumina oxide sheeting (http://www.mcmaster.com, pages 3488-3493) is great here. Even some of the fiberglass mats are good for up to 1000F.

Or, just mount a kiln on your bike. LOTS of insulation there.

 

[EBJ]

My plan is to have them all resting in an Aluminum plate box. Aluminum plate box will have vents. The vents will have a fire-resistant material covering them from the inside, in hopes that fumes are allowed to vent, but the flame doesn't follow the fumes out of the box. In which case a worst-case scenario would be a living room filled with Lipo smoke. I may also include a cheap 5 dollar fire-detector in the battery-box if room permits.

 

[dogman dan]

Yeah, a lot would depend on the application. In a race car you'd want be able to remove the pack from the car quickly and easily. That way you could get the thing out of the car if venting, and carry it seperate from the car in transport. Why risk carrying the lipo in the same trailer as the car?

If it must be permanent, then perhaps fire resistant materials inside the Alu box, which has vents directed to the rear like exhaust pipe. Might have to be big pipe though, to prevent a blev. If the pack could be located at the very rear, mabye a blow out panel?

In any application, being able to quickly remove burning lipo from the vehicle makes a lot of sense to me.

 

[Pure]

Personally if I were to put a large LiPo pack in a car, I would like to use a care that has a gas tank under the trunk of the car. I would look for one where the rear axle isn't in the way. I would build the box to replace the gas tank and make a hanger system that with the pull of a lever would allow the "tank" to be dropped out from under the car.

I'm not sure making vents covered in flame retardant material would stop the flames from exiting the box. The flames ARE going to happen, and have to go somewhere. It's enough energy that it will either push through the flame retardant material or just blow it out of the way.

I would love to see someone try this though. Perhaps someone should poke Luke and see if he can make this his next set of tests.

 

[auraslip]

Someone spoke of using fiberglass tape. Seems liked it'd be an easy way to line the inside of the box and wrap the pack.

 

[countermeasure]

It sounds like the being able to dump the "core" is the way to go.

Just for clarification, are we talking something like Star Trek, dumping the warp core type of stuff?

If everyone adopts the same strategy to eject the battery box during a fire, traveling on highway with the car in front of you ejecting a flaming battery box is going to be, hmmm, "exciting".

The other day I saw summit racing selling an aluminum battery box. (http://www.summitracing.com) I thought about buying that and drill holes at some strategic locations to encourage venting in case of fire.

Another idea I have for venting is to build venting paths out of metal HVAC ducting. HVAC ducting is readily available at Home Depot, Lowes, or other hardware stores. The ducting components will need to be treated with high temperature paint or wrapped with ceramic fiber clothes.

My old stand by is to go to asbestos lagging, but it seems that asbestos lagging is not very popular now days.

 

[dogman dan]

Perhaps better to just use a safer chemisty than lipo, in a car for the street. There is a reason the leaf, tesla, etc don't use hobby king type lipo.

Racing is another story. All you want is power then.