The Road to a Thriving Second-Life EV Battery Market
How to overcome the physical and economic challenges for used EV batteries in stationary storage

by Julian Spector
September 07, 2016

As electric vehicles proliferate, so too will used EV batteries. Car companies and researchers are hustling to figure out how to safely adapt and reuse those depleted batteries when that time comes.

The basic pitch is simple enough: cars demand very high performance from their batteries, so once the battery’s capacity declines past a certain point -- 70 percent or 80 percent, depending on who you talk to -- it needs to be swapped out. At that point, though, the battery can still handle a lot of charge and discharge, making it useful for storage in less intensive stationary settings.

The sheer expense of developing and building those batteries in the first place makes a compelling case for capturing some additional value after their initial use. Second-life applications also delay the need to dispose of these resource-intensive products, which nobody has yet figured out how to do economically. If storage vendors can resell used batteries as a cheaper alternative to new storage, they could help more people consume their own rooftop solar generation, or reduce their peak demand, or any number of other uses that would advance the progress of a low-carbon grid.

This is new territory, so there are a lot of questions yet to be resolved. What are the engineering challenges involved in taking batteries from mobile use to stationary use? Will they perform as well in the new capacity? How do you standardize across different degrees of wear and tear?

There is also the matter of setting up markets around used batteries and determining who benefits from that trade. Before that can happen, the physics of the transition ...