Flame-Out: Why E-Bikes Can Catch Fire and How to Protect Yourself

can be reached at meehna@gmail.com
can be reached at meehna@gmail.com
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The only thing you have to worry about burning up on a traditional bike is your leg muscles. Unfortunately, some riders of electric bikes have experienced a different sort of burn: batteries setting themselves ablaze.

  • A spate of battery fires have caused concerns about the safety of electric bikes.
  • E-bikes operate using lithium-ion batteries, which are more prone to combusting from thermal runway.
  • While e-bike battery fires are rare, you should be prepared in case of emergency.

As reported by Bicycling, two Lime bikes in Seattle caught fire a couple weeks ago. And just a couple months ago in July, a Lyft bike combusted outside the Hearst Memorial Mining. And, not to fan the flames, but just a few days ago another Lyft bike saw a fiery demise in San Jose, California.
Electric bikes use lithium-ion batteries because they pack more energy in a smaller, lighter package than nickel-cadmium or lead-acid types. While any battery can combust, a lithium-ion battery is more susceptible because of its relatively high energy density. Though better for performance and range, lithium-ion batteries are also more volatile.

Thermal runway

Batteries catch fire due to thermal runway. This phenomenon occurs when a cell’s temperature reaches critical mass, where it continues to increase by itself and self-sustain through the creation of oxygen from the ensuing chemical reactions. Conditions like these occur from a short circuit or overheating when charging. It has been known to happen to the lithium-ion powered Tesla too.

To compensate for the lithium-ion battery’s idiosyncrasies, most e-bikes use battery packs manufactured with cylindrical cells because they can remain stable at higher temperatures, as opposed to the flatter prismatic cells or pouch cells, which can swell and destabilize the battery. Since it costs more to build and test a lithium-ion battery with cylindrical cells, e-bikes using this type will be more expensive. Beware if the price seems too good to be true. Off-brands may cut corners with the battery.

Citi Bike
(Photo: Citi Bike)

Not necessarily a manufacturer defect

In some incendiary cases, the lithium-ion battery isn’t to blame. Damage from a drop, crash or vandalism can compromise the integrity of the cells and create the conditions for thermal runway. Thankfully, the incidence of e-bikes catching fire remains relatively rare.

After the latest fiery incidents, Lyft has shut down its program in San Francisco while the company investigates. Although, they claim it was vandalism and not faulty battery packs responsible for the incidents. Lyft and Lime aren’t the only e-bike purveyors dealing with burning batteries. In March, at Citi Bike’s main hub in Brooklyn, a charging station went up in flames.

Although the odds of an e-bike catching on fire aren’t likely, it’s better to be prepared in order to protect yourself and keep your e-bike’s lithium-ion battery in good working order.

Use the proper charger

Although it might seem obvious, always use the manufacturer’s charger. If yours breaks, avoid the aftermarket replacement or using one by another brand. The mismatch could cause overheating and lead to the dreaded thermal runway.

Supervise charging

Plug-in when someone is around. In the off chance of a fire, it can be handled immediately, and, if not, you can get other people out of harm’s way and call for help.

fire extinguisher
(Photo: Piotr Chrobot on Unsplash)

Retire batteries that could be damaged

If a battery was dropped, in an accident, punctured or otherwise gone through a trauma, get it checked out. Although the battery might not look damaged, you don’t know what’s going on inside.

Don’t store lithium-ion batteries fully charged

E-bikes with a full charge are more prone to thermal runway. Take a lap around the hood before you park it in your garage or closet.

Don’t fiddle around

Unless you’re an expert in e-bikes, leave the modifications to professionals.

Have a fire extinguisher on hand

Lithium-ion battery fires generate a lot of heat as well as toxic gas and smoke. Since lithium-ion fires are considered Class B, use a standard ABC or BC dry chemical fire extinguisher.  Do not use a Class D fire extinguisher, which contains dry powder and is for combustible metal fires only.

WHY THIS MATTERS

E-scooters are becoming more a part of everyday life. If you don’t ride one yourself, you certainly know someone who does. There’s no need to worry about the Lithium-ion battery in your e-bike igniting, but if it does, understanding how to cope with the issue increases the safety for everyone.


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can be reached at meehna@gmail.com
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