A Tesla battery researcher showed updated test results pointing to batteries lasting over 15,000 cycles or the equivalent of over 2 million miles (3.5 million km) in an electric car.
Last year, we reported on Jeff Dahn and his lab, who are under contract to do battery research for Tesla, releasing an interesting paper that shows how the latest Li-ion battery technology can produce batteries that would last 1 million miles in electric vehicles.
In a new presentation, Dahn discussed updated test results from this new battery, which he hopes becomes the new standard Li-ion battery that new battery technologies benchmark themselves against.
The scientist, who is widely recognized as a pioneer in Li-ion batteries, referenced our article from last year about their paper and said that it sparked a massive interest in this new battery chemistry and battery longevity.
They have continued testing those batteries with some of them going on 3 years of testing and over 10,000 cycles:
Dahn now concludes that these batteries in a medium range electric car would be able to last over 3.5 million km or over 2 million miles.
He also showed results based on different depths of discharge, which means to what percentage of capacity they are discharging the batteries before recharging them, and it showed the Li-ion batteries performing extremely well after up to 15,000 cycles so far:
Most impressively, the batteries show very little to no capacity degradation when they are discharged between 25% to 50% of their capacity, which is actually how most people use their cars.
On average, American drivers use their vehicles for less than 30 miles per day.
For example, with this battery in a Tesla vehicle with over 300 miles of range, you could use it to commute 30 miles a day and by charging, on average, from 70 to 80% every day, it would result in very little to no battery degradation.
Considering it would mean those batteries could virtually last forever or much longer than the actual useful life of a car, Dahn brings up the question: do we actually need batteries that are that good?
Tesla CEO Elon Musk has been saying that they plan to have batteries that would last more than 1 million miles for the automaker’s “robotaxis”, which are going to have a much higher utilization rate than consumer vehicles.
Musk has also mentioned in the past how longer-lasting batteries are critical for other Tesla programs, like Powerwalls, Powerpacks, and Tesla Semi electric trucks.
Dahn also brings up that these new super long-lasting batteries could be useful to enable vehicle-to-grid features.
Author: Fred Lambert
Source: Electrek
