Why It's So Hard To Replace A Nissan LEAF Battery - WHYY

This story is from The Pulse, a weekly health and science podcast.

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When the first Nissan Leaf came out almost 10 years ago, it was the only mass-market electric car at the time. Mike and Karen Lawrence, who are from Virginia, bought one as soon as they could, because they cared about the environment and wanted to put their money where their mouths were.

“I absolutely fell in love with it,” said Karen Lawrence.

Almost a decade on, their silver Leaf has aged well.

“It is not a pain in the neck,” she said, “because without a motor and the oil change, which we do not have to do because there ain’t none … it rarely goes in for service beyond a checkup.”

The only problem with the car is the battery. At first, a fully charged battery was enough for as much as 100 miles, but that went down over time. Now, the car can go only about 45 miles on a single charge.

Old batteries degrade and store less energy, and need to be charged more often. The Lawrences could buy a new battery from Nissan, but that would cost $8,000 — more than the car is currently worth. So they joined an active online community of Nissan Leaf enthusiasts looking for new batteries.

“It’s the search for the Holy Grail,” said Mike Lawrence.

It’s a common problem among Leaf owners — and for battery technology in general. The most expensive part of an electric car is typically the lithium-ion battery, which can account for as much as one-third of the car’s cost.

Years of research led to lithium-ion batteries, which won three scientists the 2019 Nobel Prize in chemistry. They power everything from smartphones and computers to cars, and are key to expanding the use of renewable energy. Battery technology is a hot investment right now. But there are still research questions that need to be answered before batteries can power bigger vehicles and last longer.

On a very simple level, lithium-ion batteries work this way: Lithium ions go back and forth in a liquid, and in and out of the positive and negative ends of a battery. Lithium ions going one direction means charging the battery and storing energy; going the other way means discharging the battery and using the energy to power something, such as a car.

But it took a lot of work to get lithium-ion batteries to work in a car, according to Gene Berdichevsky —  who as an undergrad at Stanford worked on a solar car project in the early 2000s. Back then, he said, most people didn’t care about batteries the way they do now.

“They were an afterthought,” he said. “We think about the modern portable electronics industry, and we talk about it as being an industry that was revolutionized by semiconductors …  people sort of miss that the battery played just an equally important role.”

The quest for power

Berdichevsky’s work on the solar car, along with another class project, led him to realize that lithium-ion batteries were getting cheaper — so cheap, in fact, that you could feasibly buy enough of them to power a car for long distances, and actually make money selling it. Electric cars have been around for more than a century, but by the early 20th century, gas powered cars, and gas, were just cheaper.

He joined a startup that was doing just that — Tesla — and went to work figuring out how to make a battery-powered car. At first, the team at Tesla took the lithium-ion batteries out of laptops, super-glued them together, and tried putting that in a car.

But there was a problem.

“Every now and then, a manufacturing defect could cause a lithium-ion cell to spontaneously more or less go into thermal runaway,” Berdichevsky said.