Technology

#What’s causing all the ebike and escooter battery fires?

“What’s causing all the ebike and escooter battery fires?”

The City of New York is grappling with a problem — fire. Specifically, escooter and ebike lithium-ion batteries catch fire and sometimes explode. And there’s no sign of it ending anytime soon.

Earlier this year, I wrote an introductory article detailing the rate of lithium-ion battery fires. Today I want to look at New York as a cautionary tale in the struggle of dealing with battery fires as ebikes (and, to a lesser extent, escooters) become mainstream. 

I’ll follow up with a third article tomorrow, exploring potential technological solutions to prevent battery fires. 

What causes battery fires? 

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In the case of ebikes and escooter fires, there are numerous causes. Firstly, when we talk about a lithium-ion ebike or escooter battery, we’re talking about a bunch of connected batteries stored in a plastic case. A huge amount of energy resides in this small space. 

Any one of the batteries is susceptible to overheating, which can be caused by;

  • poor design
  • assembly errors
  • electrical shorting
  • use of the wrong charger
  • overcharging
  • A damaged battery management system (BMS) causes overheating and inadequate cooling 
  • damage to the case. 

Once a battery overheats, it can lead to a thermal reaction inside a battery. This is known as a thermal runway event. The reaction produces enough heat to cause adjacent battery cells to also catch fire or explode. 

These fires happen incredibly quickly, and due to the self-sustaining process of thermal runaway, Lithium battery fires are also difficult to extinguish. They can leak toxic chemicals dangerous to people and pets. 

Large batteries such as those used in Electric Vehicles can reignite hours or even days after the event, even after being extinguished. Fortunately, this is far less common in ebikes and escooters. 

The problem in New York 

To date this year, 130 reported fires involving lithium-ion batteries in electric bikes and scooters in New York have been reported. Five people died. Comparatively, this time last year saw only 65 ebike and escooter battery fires.

It’s worth stressing that these fires make up only a small percentage of all blazes in New York. It’s also highly likely that the growth in ebikes and escooters residing in the city is responsible for the increase. 

But the fires are still a cause for concern, resulting in property damage, injuries, and less frequently, death. The ferociousness of a lithium-ion battery fires means multiple trucks are called, diverting attention away from other emergency services. 

Further, the fires are indicative of a bigger issue facing the city. 

New York has over 65,000 delivery workers, many of whom use ebikes. Gig economy workers take their ebike to limits beyond a daily commute, with all the risks outsourced to the riders. 

gig economy worker ebike battery