Canadian Lab Creates Tesla’s New Million Mile Battery
Tesla’s Canadian battery research partners have released a paper on a new battery cell that could last over one million miles, a performance standard they say will be useful in the robot taxis that Tesla wants to bring to market.
Tesla plans to start making a dedicated robot taxi with no steering wheels or pedals from 2024, CEO Elon Musk said in April after reporting a record net profit of US$3.3 billion in the March 2022 quarter during the Tesla first quarter earnings call.
The autonomous rideshare service will cost about as much to ride as much as a subsidized subway ticket, Musk said, also announcing that Tesla will hold a dedicated robo taxi day in 2023.
ULTIMATELY WHAT IT COMES DOWN TO IS THAT TO SELL FULL SELF-DRIVING, YOU ACTUALLY HAVE TO SOLVE REAL-WORLD ARTIFICIAL INTELLIGENCE, WHICH NOBODY HAS SOLVED. … IN ORDER TO SOLVE DRIVING, WE HAVE TO SOLVE NEURAL NETS AND CAMERAS TO A DEGREE OF CAPABILITY THAT IS ON PAR WITH, OR REALLY EXCEEDS, HUMANS. AND I THINK WE WILL ACHIEVE THAT THIS YEAR.
The Tesla cars currently built are all designed for a million miles of operation; the drive unit is designed, tested, and validated for one million miles of operation. But Musk acknowledged that the battery packs are not built to last a million miles.
Earlier this year, Musk said that they built the Tesla Model 3 to last as long as a commercial truck, a million miles, and the battery modules should last between 300,000 miles and 500,000 miles.
Now, Musk claims that Tesla has a new battery coming next year that will power the cars for a million miles.
Million Mile Battery Born at a Canadian University
In 2015, Tesla entered an exclusive research collaboration with world-famous battery scientist and Herzberg Gold Medal winner, Dr. Jeff Dahn, the first time the company had ever worked with a university.
Dr. Dahn is a professor in the Department of Physics & Atmospheric Science and the Department of Chemistry at Dalhousie University in Halifax, Nova Scotia. He is known as one of the pioneering developers of the lithium-ion battery used worldwide in laptop computers, cell phones, and electric cars.
Dr. Dahn pioneered the science of lithium-ion batteries in the 1980s; he is the co-inventor of 65 inventions with patents issued or filed. Tesla signed a five-year partnership with Dahn and his lab in 2016 and in 2021 extended the partnership for another five years. Tesla now has exclusive rights to breakthroughs coming out of Dahn’s lab until 2026.
Now, Dahn has released test results for a new battery cell that is likely to be Tesla’s new million-mile battery. Still, Dr. Dahn is not celebrating yet.
UNTIL YOU PUT IT IN A PROTOTYPE AND YOU DEMONSTRATE THAT IT'S A MANUFACTURABLE ITEM AND ECONOMICALLY VIABLE, YOU CAN'T JUMP UP AND DOWN TOO MUCH.
Dr. Jeff Dahn
Professor and NSERC/Tesla Canada Industrial Research Chair, Department of Physics and Atmospheric Science, Dalhousie University
Tesla currently manufactures and uses a lithium iron phosphate (LFP) battery, which offers higher energy density with longer range between charges than previous battery technologies.
The nickel-based alternative described by the Dalhousie researchers overcomes the energy density and durability limitations of the LFP battery, while offering a much improved life cycle.
The new battery is a Li-Ion battery cell with a next-generation "single crystal" NMC cathode and a new advanced electrolyte.
The Science, the Details
NMC is the battery of choice for power tools, e-bikes and other electric powertrains. The cathode combination is typically one-third nickel, one-third manganese and one-third cobalt, also known as 1-1-1. This offers a unique blend that also lowers the raw material cost due to reduced cobalt content. Another successful combination is NCM with 5 parts nickel, 3 parts cobalt and 2 parts manganese (5-3-2). Other combinations using various amounts of cathode materials are possible, according to Battery University, a Canadian company founded by battery engineer Isidor Buchmann.
In addition to Dr. Dahn, Tesla has added Dr. Michael Metzger as Herzberg-Dahn Chair. At Tesla, Dr. Metzger’s research group focuses on developing new methods to study the performance and lifetime of advanced lithium-ion batteries, lithium metal batteries, and desalination batteries.
And on May 9, the scientists released a paper detailing the new chemistry that can power a battery for 100 years. In the paper, published in the Journal of The Electrochemical Society titled "Li[Ni0.5Mn0.3Co0.2]O2 as a Superior Alternative to LiFePO4 for Long-Lived Low Voltage Li-Ion Cells," Dr. Metzger and Dr. Dahn detail a new nickel-based battery with a superior life cycle.
Dahn’s team has been doing extensive tests with these cells and based on the results, they now believe that the battery could power an electric car "for over 1.6 million kilometers (1 million miles)."
"We present a wide range of testing results on an excellent moderate-energy-density, lithium-ion pouch cell chemistry to serve as benchmarks for academics and companies developing advanced lithium-ion and other ‘beyond lithium-ion’ cell chemistries to (hopefully) exceed," Dahn’s team explains.
"These results are far superior to those that have been used by researchers modeling cell-failure mechanisms, and as such, these results are more representative of modern Li-ion cells and should be adopted by modelers. Up to three years of testing have been completed for some of the tests," the Dalhousie team wrote.
"Tests include long-term charge-discharge cycling at 20, 40, and 55°C, long-term storage at 20, 40, and 55°C, and high precision coulometry at 40°C," they wrote.
"Several different electrolytes are considered in this LiNi0.5Mn0.3Co0.2O2/graphite chemistry, including those that can promote fast charging. The reasons for cell performance degradation and impedance growth are examined using several methods. We conclude that cells of this type should be able to power an electric vehicle for over 1.6 million kilometers (1 million miles) and last at least two decades in grid energy storage," the researchers concluded.
The battery cells tested at Dalhousie last two to three times longer than the battery cells used in Tesla's current models.
In the research paper, Dahn’s team explain that this new longevity potential would be especially good for robo taxis.
"This situation may change with the proposed introduction of "robo taxis," long-haul electric trucks, and vehicle-to-grid applications. In the former, vehicles will be driving all day, much like a conventional taxi and undergoing nearly 100% DOD cycling," they wrote.
The abbreviation DOD stands for Depth of Discharge - how much energy is cycled into and out of the battery on a given cycle.
Long haul trucks will almost certainly run in near 100% DOD situations. Cells in vehicles tethered to the grid will be racking up charge-discharge cycles, even when the vehicle is not moving," the Dalhousie researchers wrote.
"Clearly EVs destined for vehicle-to-grid applications, robo taxis, or long-haul trucking would favor a lithium-ion chemistry that could deliver many more charge-discharge cycles in a decade than an EV that was destined for typical commuter driving where high energy density to give the longest driving range for weekend trips might be emphasized. Electric buses represent another application where duty cycles approaching 100% DOD are used on a daily basis," Dahn's team explained.
Their research paper concludes, "Future work on low voltage NMC cells includes application of this cell design to fast charge applications, use of low cobalt and high nickel NMC materials and the use of blended NMC and LFP positive electrodes."
Dr. Dahn has announced plans to step down from his leadership role at Tesla's Advanced Battery Research group to become chief scientific advisor at Novonix Battery Technology Solutions, a company that emerged from Dahn's research group in 2013.
Still, Dahn and his research group will continue with Tesla research at Dalhousie at least until 2026.