[SystemSafety] E-bike battery fires in NY

[Peter Bernard Ladkin]

In NYC there have been about two hundred building fires and 6 deaths this year due to e-bike 
batteries catching fire 
https://www.theguardian.com/us-news/2022/nov/14/new-york-e-bike-batteries-fires-delivery-workers

The issue, as we know, is that lithium-ion batteries are not particularly safe, and are prone to 
"thermal runaway" as it is called, . Safety has to be designed and manufactured in, and 
manufacturing quality control has to be very good (recall the Boeing 787 had trouble with its 
batteries, causing some fires, and the NTSB was scathing about the quality control at its 
manufacturer - and that is aerospace!).
And sometimes it isn't.

The article talks about measures such as only having batteries certified by UL in circulation. That 
seems to be impractical for people who work in low-income city-delivery jobs. But that seems to be a 
matter of regulatory choice -- maybe the city resources devoted to extinguishing those two hundred 
fires could be better targeted at battery certification and control?

There are three reasons for the relative unsafety of lithium-ion batteries. Two concern ignition and 
fire. One is the relatively low temperature at which lithium spontaneously combusts, which can be 
attained in spikes in the electrodes when charging or damaged; the other is the presence of gases, 
within the battery, which burn. The two phenomena lead to a process called "thermal runaway". The 
third is that lithium-battery fires are hard to extinguish.

A decade ago, I chaired the DKE committee (German electrotechical standards organisation) looking at 
the risk analysis of charging electric road vehicles (cars and trucks, not low-voltag systems such 
as bikes). The auto industry went to some lengths to try to cancel the working group and eventually 
succeeded.

Causalis also worked on the case of one particularly expensive lithium-battery fire.

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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