How to Reduce Fire and Injury Risks from Lithium-Ion Batteries

Give residents safety tips for charging and maintaining e-bikes.

E-bikes, e-scooters, e-mopeds, and other small electric mobility devices have experienced a surge in popularity. These devices use a small electric motor to increase their range and reduce the effort it takes to reach a destination. For example, e-bikes look and behave like traditional bicycles with the addition of an electric motor and battery for extra power when pedaling. This extra boost allows the rider to traverse hills and travel further distances with greater ease than with a traditional bicycle.

Although the benefits of micromobility devices in terms of lower emissions and easier transportation are considerable, the rapidly expanding use of lithium-ion batteries is posing new challenges for firefighters across the country. The number of injuries and deaths from fires started by lithium-ion batteries in micromobility devices is growing.

Recently, New York City’s top fire official asked the federal government to do more to keep substandard lithium-ion batteries out of the United States and regulate chargers and electric bikes, after hundreds of battery fires and six fatalities in the city in 2022. Fire Commissioner Laura Kavanagh submitted a letter to the head of the Consumer Product Safety Commission thanking the agency for its work in issuing multiple recalls of flawed e-bikes, but urging it to seize more substandard batteries at ports, ban “universal” battery chargers, and push e-bike and scooter companies to make their devices work only with approved batteries.

Kavanagh noted that in one incident last year, FDNY firefighters had to use ropes hanging out of the 20th floor of an apartment building to save people trapped by a blaze. The cause of this particular fire, which injured 43 people, was determined to be a micromobility device residents left charging overnight by their front door. According to FDNY Chief Marshal Daniel Flynn, at the time, this was the 200th fire caused by lithium-ion batteries in the city in 2022 and there had been more deaths and injuries from e-bike fires in 2022 than in the prior three years combined.

According to a recent memo HUD sent to multifamily owners and managing agents highlighting the potential fire hazards of these devices, from 2017 to 2021 annual injuries spiked 127 percent to 77,200 for the devices, and the annual number of deaths rose from five to 48. Fires caused by the lithium-ion batteries in these devices are one of three main causes of related injuries and deaths, the other two being motor vehicle collisions and user-control issues.

We’ll take a look at the particular dangers caused by lithium-ion battery fires and what owners and residents can do to help prevent electric scooter and bike-related fires. We’ve also included a flyer, “E-Scooter and E-Bike Safety Tips,” that you can post in prominent locations in your buildings to remind staff and residents about these lithium-ion battery dangers and fire prevention tips.

Dangers of Lithium-Ion Battery Fires

Nearly all micromobility vehicles are powered by lithium-ion battery packs. Lithium-ion batteries are popular because of how much power they can put out at a given size and weight. However, lithium-ion batteries are extremely sensitive to high temperatures and inherently flammable. These battery packs tend to degrade much faster than they normally would, due to heat. If a lithium-ion battery pack fails, it will burst into flames and can cause widespread damage.

Batteries can fail and become dangerous due to manufacturing defects, improper usage such as keeping the battery very close to a heat source, charger issues, or low-quality components such as a poor battery management system that keeps battery cells in sync to make sure that cells don’t overcharge or release too much energy at once.

While elaborating on the nature of these types of battery fires, Chief Marshal Flynn has stated, “These bikes when they fail, they fail like a blowtorch. We’ve seen incidents where people have described them as explosive incidents where they actually have so much power, they’re actually blowing walls down in between rooms and apartments.”

Lithium-Ion Battery Safety Guidelines

Lithium-ion batteries supply power to many kinds of devices including electric scooters and electric bikes. If not used correctly, or if damaged, these batteries can catch on fire or explode. The concern from a fire safety perspective is that these batteries store a large amount of energy in a small amount of space. Sometimes batteries are not used the right way and batteries not designed for a specific use can be dangerous. Also, like any product, a small number of these batteries are defective. They can overheat, catch fire, or explode.

Here are safety recommendations from the U.S. Consumer Product Safety Commission:

• Always be present when charging devices using lithium-ion batteries. Never charge these batteries when away from the apartment;
• Only use the charger that came with your device. Unapproved chargers may cost less, but they carry a higher risk of fire;
• Only use an approved replacement battery pack. Unapproved batteries may cost less, but they carry a higher risk of fire;
• Follow the manufacturer’s instructions for proper charging and unplug the device when done;
• Never charge while sleeping;
• Never use these devices with a battery pack that has been modified/reworked by unqualified personnel or with re-purposed or used cells; and
• Never throw lithium batteries into the trash or general recycling. Instead, take them to your local battery recycler or hazardous waste collection center.

Danger signs. As part of the NYC Fire Department’s response to the dangers posed by lithium-ion batteries, the department updated its Fire and Emergency Preparedness Bulletin with information on what residents or staff should do if there are signs of a problem with lithium-ion batteries. Residents should stop using the lithium-ion batteries if they notice any danger signs. If it is safe to do so, residents should move the device away from anything that can catch fire and call 911. The bulletin instructs residents to stop charging devices immediately and to call 911 if they see any of the following danger signs:

• Fire or smoke;
• Battery leakage;
• Signs of battery overheating;
• Strange battery smell; or
• Battery making odd noises.