[SystemSafety] E-bike battery fires in NY

[Peter Bernard Ladkin]

On 2022-11-15 10:13 , M Ellims wrote:
> For some perspective - it's not just batteries...

I would distinguish battery safety from electrical safety in general. The causes of battery fires 
are physico-chemical and very different from the causes of electrical-circuitry fires.

> However the risk of a single cell failing can simply be mitigated in many cases, research > from NASA and NREL suggests that by simply separating cells from each other by 1-2mm
> almost removes the risk of a chain reaction occurring. 

It depends how big the cell is; it depends how the separation is achieved. Safety also depends upon 
the design of the containment structure. When Tesla started out, they claimed their battery design, 
following these principles, was such that thermal runaway on a cell was contained. Part of the 
solution to the Boeing 787 problem was a heavy containment structure that more or less undid all of 
the claimed weight advantages of lithium-ion main batteries.

> It would also probably be better if lithium iron phosphate chemistries were used 

What are those? Linden's 4th edition (2011) has lithium iron disulphide but no lithium iron 
phosphate amongst the combinations.

> nickel-magnesium-cobalt (LFP vs NMC) 

What are those? Again, Linden's 4th doesn't have them.

PBL

Prof. i.R. Dr. Peter Bernard Ladkin, Bielefeld, Germany
Tel+msg +49 (0)521 880 7319  www.rvs-bi.de




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