Historical data from Tesla’s current battery packs show about 5% capacity degradation after 50,000 miles (80,000 km) and the capacity levels off for about 150,000 more miles before hitting 90% capacity.
Those are already pretty good results, but Tesla aims to do better with Jeff Dahn, a renowned battery researcher and the leader of Tesla’s research partnership through his battery-research group at Dalhousie University.
The scientist and his team recently unveiled their latest research on a new chemistry that could enable even more cycles without significant degradation.
Dahn is considered a pioneer in li-ion battery cells since he has been working on the batteries pretty much since they were invented. He is credited for having help increase the life cycle of the cells, which helped their commercialization. His work now focuses mainly on a potential increase in energy density and durability.
Last year, Dahn transitioned the group from their 20-year research agreement with 3M to a new association with Tesla under the newly formed ‘NSERC/Tesla Canada Industrial Research’.
Through the agreement, Tesla invested in a new research lab close to Dahn’s group near Halifax, Nova Scotia.
At the International Battery Seminar & Exhibit in March, Dahn presented his new research to improve the chemistry of NMC Li-ion in order to limit the gasses generated by the cells when operating at high voltage.
The improved cells that they created from their research have performed exceptionally well after over 1,200 cycles:
If made into a car battery pack, 1,200 cycles would translate to roughly 300,000 miles (480,000 km) – meaning that a battery pack could still retain about 95% of its original energy capacity after ~300,000 miles – or 25 years at the average 12,000 miles per year.
Those results are truly impressive – especially since Dahn said that his team’s research is already “going into the company’s products“.
In his presentation – embedded below, Dahn demonstrates how they virtually removed the harmful reactions in the positive electrode – leading to what they describe as “superb NMC Li-ion cells that can operate at high potential.”
Interestingly, Tesla currently uses nickel cobalt aluminum (NCA) battery cells for its vehicles. For its stationary energy storage products, like the Powerwall and Powerpack, the company uses nickel manganese cobalt oxide (NMC) cells, which typically have a longer cycle life, but less energy density.
It would be interesting to see if that changes following Dahn’s research and Tesla’s new ‘2170’ cells that went into production in January at the Gigafactory.
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