Tesla Patents Long-Life EV Battery

Tesla Inc. has received a U.S. patent for an optimized lithium-ion battery design that promises to last significantly longer than units used in current electric vehicles, with minimal loss of energy capacity during the battery’s lifecycle.

Researchers from Canada’s Dalhousie University tested a similar battery for Tesla and say it should be able to power an electric vehicle for more than 1 million miles. That’s more than twice the capacity of most current EV systems and fulfills a vow last year by Tesla CEO Elon Musk to eventually offer a 1 million-mile EV.

Dalhousie signed an exclusive development contract with Tesla in 2016. Physicist Jeff Dahn, who led the university team, also is listed on the Tesla patent.

The research, which covers three years of testing in various conditions, is published in The Journal of the Electrochemical Society. Dahn says the detailed description of the battery should be used as a benchmark for other battery developers. Media reports speculate that the patented battery could have an even longer lifecycle than one described by the researchers.

The new battery design features the same basic chemistry—a nickel manganese cobalt oxide (NMC) cathode and artificial graphite anode—used in most current EVs. But the cathode has larger NMC crystals, which Dahn says makes the nanostructure less likely to crack during charging and enhances the battery’s overall durability.

The researchers figure the battery could be charged and depleted more than 4,000 times and lose less than 10% of its energy capacity over its lifetime. Typical current-generation lithium-ion batteries lose half their capacity after 1,000 cycles.

Dahn notes that longer-lasting batteries would be especially useful in future robo-taxi and long-haul electric trucks. Tesla is expected to launch its electric semi-truck within the next few months.