New York City’s plan to stop e-bike battery fires

Existing battery swap networks like Nio’s have mostly included a single company’s equipment, giving the manufacturer control over the vehicle, battery, and swapping equipment. That’s because one of the keys to making battery swapping work is fleet commonality—a base of many vehicles that can all use the same system.

Fortunately, delivery drivers have formed something of a de facto fleet in New York City, says David Hammer, co-founder and president of Popwheels. Roughly half of the city’s 60,000-plus delivery workers rely on e-bikes, according to city estimates. Many of them use bikes from a brand called Arrow, which include removable batteries.

Convenience is key for delivery drivers working on tight schedules. “For a lot of people, battery charging, battery swapping, it’s just technology. But for [delivery workers], it’s their livelihood,” says Irene Figueroa-Ortiz, a policy advisor at the NYC Department of Transportation.

For the New York pilot, Popwheels is building battery cabinets in several locations throughout the city that will include 16 charging slots for e-bike batteries. Riders will open a cabinet door using a smartphone app, plug in the used battery and take a fresh one from another slot. Based on the company’s modeling, each cabinet should be able to support constant use by 40 to 50 riders, Hammer says.

“Maybe it leads to an even larger vision of battery swapping as a part of an urban future,” Hammer says. “But for now, it’s solving a very real and immediate problem that delivery workers have around how they can work a full day, and earn a reasonable living, and do it without having to put their lives at risk for battery fires.”

A growing problem

Lithium-ion batteries power products from laptops and cellphones to electric vehicles, including cars, trucks, and e-bikes. A major benefit of the battery chemistry is its energy density, or ability to pack a lot of energy into a small container. But all that stored energy can also be dangerous.

Batteries can catch fire during charging or use, and even while being stored. Generally, fires happen when temperatures around the battery rise to unsafe levels or if a physical problem in a battery causes a short circuit, allowing current to flow unchecked. These factors can set in motion a dangerous process called thermal runaway.

Most batteries include a battery management system to control charging, which prevents temperatures from spiking and sparking a fire. But if this system malfunctions or if a battery doesn’t include one, charging can lead to fires, says Ben Hoff, who leads fire safety engineering and hardware design at Popwheels.