This past week I attended a workshop organized by the National Highway Traffic Safety Administration (NHTSA) and SAE International focusing on the issue of stranded energy in electric vehicles. The workshop was organized by Phil Gorney of NHTSA and Bob Galyen of SAE International and took place at Argonne National Laboratory outside Chicago.
Stranded energy is difficult to define precisely (in fact workshop participants spent about 90 minutes trying to agree on a definition). But the general, imprecise meaning of the term is the electrical energy that remains in a high voltage vehicle battery after the vehicle is no longer operative. Stranded energy is a serious and potentially deadly problem after a crash or at other times after a vehicle is removed from normal operation.
The danger that stranded energy poses to first responders has been widely discussed. There are already procedures in place and related training intended to reduce the risk to first responders who arrive on the scene of a crash and need to rescue survivors or put out a fire. The workshop highlighted a number of technologies under development that might help first responders better identify and minimize their risk in the first minutes follow a crash.
But the real take-away from the workshop is that stranded energy is a problem that goes well beyond risks to first responders. Once survivors are removed from a crash site, it is often unclear, and often varies from jurisdiction to jurisdiction, who will be tasked with securing, transporting and storing a vehicle whose battery may still pose a significant risk to human safety. In addition to first responders, there are second responders, third responders, transporters, salvage yard operators, battery repurposers, and members of the general public to whom a high voltage vehicle battery may remain a risk for some time. There are few procedures or training programs currently in place to protect those persons.
As Dirk Spiers of Spiers New Technologies noted in the closing panel presentation, the scariest part of the workshop was a presentation by Ricardo outlining its study of post-crash vehicle batteries. The presentation featured photos of several wrecked Tesla Model S’s in a junk yard. Ricardo was able to purchase and remove the wrecked batteries from the yard without difficulty. The presenter from Ricardo said that it is amazing how many xEV’s are sitting in junk yards today with their potentially charged and highly dangerous batteries still installed.
We are still at the beginning of the discussion about the hazards of stranded energy. To date, the discussion is being driven by forward thinkers in the industry, such as Messrs. Gorney and Galyen. But if, and unfortunately inevitably when, an injury to a member of the general public starts driving the discussion, the discussion about stranded energy will become a lot less pleasant for the industry and for vehicle OEM’s. As an industry, we need to get our hands around this problem long before the tone of the discussion turns sour.