Last year, Tesla and Jeff Dahn’s battery-research group at Dalhousie University announced a new partnership that 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’.
While announced last year, the partnership only went into effect in June 2016. The group just released its first research paper since and it could lead to a potential increase in energy density and durability.
Dahn’s research focuses on extending the lifespan of Li-ion battery cells, which is obviously something of high interest for Tesla.
The new paper will be published in the October edition of the Journal of Power Sources and it is co-authored by Dahn himself and 4 other members of his battery-research group and members of Dalhousie University’s Physics and Chemistry departments: Jian Xia, Remi Petibon, Deijun Xiong, Lin Ma.
The paper states that ethylene carbonate (EC), an organic compound until now thought to be an essential electrolyte component for Li-ion cells, is “actually detrimental for cells at high voltages” – 4.5 V and above. Tesla/Panasonic’s current cells are believed to be around 4.2 V, but the upcoming cells to be produced at the Gigafactory are expected to have a higher voltage.
In order to replace EC in the electrolytes, the group developed “EC-free linear alkyl carbonate electrolytes” and tested them in pouch cells. They report “excellent charge-discharge cycling and storage properties” and better cyclability of cells than cells with EC.
The researchers are hopeful that it could lead to better high-voltage battery cells:
“Further optimizing these linear alkyl carbonate electrolytes with appropriate co-additives may represent a viable path to the successful commercial utilization of NMC/graphite Li-ion cells operated to 4.5 V and above.”
Higher voltage could lead to more energy dense battery packs to achieve longer all-electric range. Better cyclability could also help extend the lifespan of the cells and therefore the battery packs, which is the focus of Dahn’s research as previously mentioned.
Dalhousie University’s battery-research group are working closely with Tesla CTO JB Straubel and Kurt Kelty, Tesla’s Director of Battery Technology, through the new partnership.