A Tesla battery researcher showed updated test results that pointed to batteries that lasted 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, which released an interesting paper showing 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 will be the new standard Li-ion battery that new battery technologies benchmark against.
The researcher, who is widely recognized as a pioneer in the field of Li-ion batteries, referred to our article from last year on their paper and said that it sparked a massive interest in this new battery chemistry and battery life.
They have continued to test these batteries, some of which continue with 3 years of testing and over 1
Dahn now concludes that these batteries in a medium-sized electric car would be able to last over 3.5 million km or over 2 million miles.
He also showed results based on different discharge depths, which means what percentage of capacity they discharge the batteries before recharging, and it showed that the Li-ion batteries perform extremely well after up to 15,000 cycles so far:
Most impressively, the batteries show very little or no capacity degradation when discharged between 25% and 50% of their capacity, which is actually how most people use their cars.
On average, American drivers use their vehicles less than 30 miles a day.
For example, with this battery in a Tesla vehicle over 300 miles range, you can 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 or no battery degradation.
Considering that this would mean that these batteries could last almost forever or much longer than the actual life of a car, Dahn raises the question: do we actually need batteries that are so good?
Tesla CEO Elon Musk has said they plan to have batteries that would last more than 1 million miles for the automaker’s “robot taxi,” which will have a much higher utilization rate than consumer cars.
Musk has also previously mentioned how long-lasting batteries are critical for other Tesla applications, such as Powerwalls, Powerpacks and Tesla Semi-electric trucks.
Dahn also says that these new super-durable batteries can be useful in enabling vehicle-to-grid functions.
In the past, Tesla has been reluctant to allow owners to use the batteries in their cars to discharge energy into the grid due to the impact on battery life, but these new batteries would solve these problems.
Interestingly, Drew Baglino, one of Tesla’s leading engineering executives, recently mentioned that future Tesla vehicles will have two-way chargers that enable technologies from vehicle to network or vehicle to everything.
Dahn brought up several other interesting potential uses of extremely long-life batteries and briefly commented on Tesla’s ‘Battery Day’ in the presentation:
“Tesla is moving forward at the speed of light. They are upscaling their factory. They know they need terawatt-hours with batteries for both energy storage and vehicles. It’s an incredibly exciting time. ”
Here is Jeff Dahn’s new presentation in its entirety:
Very interesting and impressive new test results here.
This is especially interesting as the lifespan is not something Tesla talked much about during the battery day presentation.
It focused primarily on cost and scale, but Tesla has been guiding for a while now that they are improving the lifespan a lot, and many of these improvements seem to come from Jeff Dahn’s lab.
Older Tesla vehicles have already shown only limited battery death, and in general batteries in Tesla vehicles already appear to be quite large, but it is fascinating to think that longevity in the near future may be so great that it allows new functions and various utility cases.
As usual, Jeff Dahn does not reveal if or when Tesla will implement these changes, but since the company now manufactures its own cells, I would not be surprised if the Tesla 4680 cells have a crazy long life.
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