Lithium-ion batteries in e-bikes and other devices pose fire risks

A lithium-ion battery in an apartment with at least five e-bikes caused a fire in Manhattan this month that injured almost 40 people. The fire, which was one of 188 caused by lithium-ion batteries in New York City this year, led to warnings about risks associated with the batteries and ways to minimize them.

Lithium-ion batteries power devices in every corner of our lives, including phones, laptops, toothbrushes, power tools and electric vehicles. But many don't know how to handle them safely or that they might start fires.

How do lithium-ion batteries work?

Lithium-ion batteries are rechargeable, last a long time and store a lot of energy in a small space. That has made them the most popular power source in electronic devices and vehicles, said Victoria Hutchison, a research project manager at the Fire Protection Research Foundation.

Cells in the battery heat as they charge, and when the battery overheats, it causes something like a chain reaction with the other cells, she said.

Battery fires are quick and destructive.
Fires involving lithium-ion batteries have become more common in New York City: Six people died and 139 have been injured as a result of battery-caused fires so far this year, according to the New York Fire Department. Last year, the batteries were connected to fires that resulted in four deaths and 79 injuries, the department said.

The battery that caused a Nov. 5 fire was charging near the front door of an apartment, blocking its only exit and prompting firefighters to conduct a rope rescue of two occupants. And in August, a fire caused by a lithium-ion battery killed a mother and daughter in the Harlem borough of New York City.

These fires can occur without warning and spread quickly, the chief fire marshal, Daniel E. Flynn, said at a Nov. 7 news conference.

"We have a fully formed fire within a matter of seconds," he said.

Take these simple steps to reduce the risk of batteries failing.
One out of every 10 million lithium-ion batteries fails, a condition that almost always leads to a fire, Hutchison said. While that is a relatively low rate, the batteries are being used more in devices, and unaccredited batteries sold at low prices can pose a risk, she said. Customers should always buy batteries and devices that have been certified by UL, which performs safety testing.

Fires have also been started because people have used chargers incompatible with a battery, she said. A good cable will stop charging the device when it reaches full power. However, some of the uncertified cords will continue to charge the battery to the point of overheating.

"Once it reaches its thermal threshold, it's a pretty violent reaction," Hutchison said.

Lithium-ion batteries show signs that they need to be replaced if they get hot, expand or take longer than usual to charge, Hutchison said. Immediately before failure, a battery will make a popping noise and then a hiss in which gas is released. Experts recommend storing them in fireproof containers.

Even a battery that complies with safety guidelines when it's first purchased can become dangerous if it's damaged, said William S. Lerner, a hydrogen expert and delegate for ISO, an organization for global standardization.

"These batteries can be of the highest quality, but if they are injured and dropped and severely beaten up, then the potential to fail is greater," he said.

It's a widespread problem but not well-regulated.
No large-scale database keeps track of battery-caused fires, Lerner said. But the fires have occurred around the world.

The popularity of e-bikes in New York City grew during the pandemic as people looked for alternatives to public transportation and ride-hailing services, Lerner said. But their use increased before the government could put guidelines in place.

The New York City Housing Authority had proposed a ban on storing e-bikes in buildings but faced pushback from people like food couriers whose jobs depend on them. The authority said it is still working on steps for a proposed new rule.

The issue remains top of mind for housing managers. A sign outside the Manhattan apartment complex where the fire this month occurred read, "No pedal or e-bikes allowed beyond this point."

The City Council was set to discuss e-bike battery safety Monday. Laws that would ban sales of noncertified batteries and require educating people about the risks of powered mobility devices are among the measures being considered.

Leny Feliu, a founder of Safer Charging, said her brother is a delivery person. "He makes his money that way, and I want him to continue to make his money, but we need to provide a safe way of charging these items," she said.

Property management companies Douglas Elliman and AKAM, which oversee about 700 apartment complexes in New York City, have begun to communicate with residents and managers about lithium-ion battery safety.

"We want to be proactive, not reactive," said Chris Alker, vice president of operations for AKAM. "We don't want to wait for a fire in order to address situations like these."

Proper care and recycling are crucial.
After the batteries have exhausted their life spans, which can vary, the next step is safe disposal - not throwing them in household trash, which is illegal in some states, including New York. Some companies such as Home Depot and Best Buy accept used lithium-ion batteries. Some states require retailers to accept customers' rechargeable batteries for recycling. Consumers can also contact battery manufacturers for disposal options.

Call2Recycle works with 52 brands and 75 bike shops to repurpose the batteries' metal components, said Leo Raudys, the group's CEO. Since starting to accept lithium-ion batteries in March, it's received 18,000 pounds of them.

"These batteries are phenomenal, and when people follow best practices and make good batteries, they're safe; they're reliable," he said, adding, "The problem is we're seeing bad actors out there that are marketing and selling batteries that are unsafe or not certified."