Mitigating FIRE risk


#1

We all know that fire risk is always present with many of these batteries. I’m definitely no expert but I know that Tesla surrounds their batteries with some sort of fire retardant substance. Also NASA is working with a US battery maker to come up with new FAA regs. I believe the batteries being tested have a BMS (battery management system) that will isolate an overheating cell. Maybe the easiest solution for us is to put these batteries in a fireproof box, with a heat sensor. If the sensor tells us of an overheat situation - maybe we can just eject the box?

What does eerybody think?


#2

there’s another thread about an “emergency battery release mechanism” - I searched for it, but could not find it, maybe you try again?

In regards to the RC lipo (Bonka, Multistar), they have indeed a higher risk of catching fire than other battery chemistries or built types, such as the Lithium Ion 18650 cells.
there is a (rather long) thread about that as well.

I am in the process of building such a pack, including a BMS

It is going to be a 13S15P Setup which is 48Volts with a capacity of 45Ah

A battery back built with 18650 cells is also what was included in earlier Tesla Models and what is used by another paramotor with single engine setup: http://www.paracell-products.com


#3

A BMS that can monitor individual cells and remove them from the system when they overheat would be great. I know the technology is out there but not sure of the complexity and cost for our purposes.

The BMS you’re building, what type of safety system might it have?


#4

A true BMS of that sort is out of the scope of this project. The “BMS’” people tend to use on home built packs are not a full BMS, and generally beyond the scope of most.

They are usually simply a low voltage cutoff, high voltage cutoff, and current switch in the case of excessive load on the pack.

Some of them offer individual cell voltage monitoring, but will not remove them from the circuit and it only used to disable the entire pack in the event of a cell failure or imbalance condition.


#5

I think a battery thermal cutout and possibly a release mechanism would be sufficient… I am a hybrid certified tech and even in the LG lithium Ion packs there is not even individual cell balancing… what I’m saying is simple is best…