Working with car companies, battery developers and policy makers, University of Michigan researchers have developed a framework to help stakeholders navigate toward a future with better, more affordable and more sustainable electric vehicles.
Greg Keoleian, a professor at the U-M School for Environment and Sustainability, and colleagues assessed economic, environmental and social trade-offs and outlooks from the perspective of stakeholders across the entire battery life cycle. This enabled the team to create a framework that stakeholders—from battery and vehicle manufacturers to drivers to battery recyclers—can use to better understand, anticipate and prepare for trade-offs and consequences as they make decisions and set priorities.
“There are multiple problems that need to be addressed in this journey, but ultimately these vehicles outperform internal combustion engine vehicles,” Keoleian said. “We know that they are the future.”
Looking at the different battery chemistries that are being used and developed for EVs helps provide concrete examples of the types of trade-offs highlighted by the framework. In China, where more than 60% of new car sales are electric, EV manufacturers have come to rely on a battery chemistry using lithium iron phosphate, abbreviated LFP. Compared with another popular battery chemistry known as NMC for its nickel, manganese and cobalt components, LFP batteries are less expensive.
But LFPs require more battery mass to achieve the same level of charge storage as NMCs. That translates to less range for an LFP vehicle. And because cobalt and nickel are valuable, there's more incentive to recycle these batteries, which would let battery makers create them more sustainably by mining less new materials for each new battery.
American automakers, including Ford and General Motors, are also developing LMR batteries, or lithium manganese-rich batteries, that have potential to marry the low cost of LFPs with the longer range of NMCs. Their durability, however, is a work in progress.
“There are a lot of different trade-offs and this framework helps elucidate what they are from different stakeholder perspectives,” said Keoleian. “If you have blinders on, you can think you're really improving sustainability and performance, but you may actually be causing problems somewhere upstream or downstream.”
Data from University of Michigan