BMW says it will partner with Colorado-based Solid Power, a 2017 C&EN Start-up to Watch. The companies will work together to develop solid-state batteries as part of the automaker’s quest to extend driving range in its line of electric vehicles.
Launched in 2012 as a spin off from the University of Colorado, Boulder, Solid Power has developed inorganic materials that replace liquid electrolytes in lithium ion batteries. Batteries with the solid electrolyte have higher energy density than standard lithium-ion batteries, meaning drivers can travel farther between charges.
The sulfide-based solid electrolyte can also withstand temperatures up to 150 °C, conditions that can cause batteries with liquid electrolytes to catch fire. Liquid electrolytes contain volatile and flammable components not needed with solid versions.
In addition to the new electrolyte, Solid Power has developed polymer binders to protect the solid-state battery’s lifespan as well as separator chemistry and a coating process to ensure the electrolyte can safely and efficiently pass lithium ions between the battery’s electrodes.
“This technology has great potential to provide the BMW Group’s electric vehicles with increased driving range and a battery with a longer shelf-life that can withstand high temperatures,” the automaker says.
BMW says it chose to work with Solid Power in part because the start-up has kept a close eye on costs. U.S. automakers are targeting an electric vehicle battery price of $125 per kWh by 2020, down from $227 in 2016. But projections by the consulting firm McKinsey & Co. suggest prices will only fall to $190 per kWh by the end of the decade.