With the release of more and more hybrid and EV models, it may be difficult to understand some of their more subtle differences. In the case of hybrids and plug-in hybrids, while there are certainly some engineering differences, from an emergency responder perspective they are handled the same.
Hybrids are self-contained units that use both electric motor(s) and an internal combustion engine (ICE) to propel the vehicle. The high voltage battery is recharged through power taken from the ICE and through a process called regenerative braking that captures energy from the braking process. Both of these methods ensure that the user never has to consciously make an effort to charge the battery, it’s done automatically.
Plug-in hybrids are simply an offshoot of that concept; they allow for a connection to be made to a Level I or Level II charging station for another charging source for the high voltage battery. These vehicles also include a larger capacity battery to store that extra energy and improve the overall energy efficiency of the vehicle. In the event that you cannot connect to a charger, the high voltage battery is recharged through the same means as a standard hybrid. Ironically enough when hybrids first were released, there was a concern among manufacturers that people would not understood that they did not need to be plugged in. A decade later that concept has become more acceptable to the general public and the plug-in hybrid was born.
There is essentially no difference for the first responder in how we handle these vehicles in an emergency situation. Both types contain a high voltage power source and an internal combustion engine with a fuel source and should be treated as such. The only real difference would occur if the plugin hybrid was attached to the charging station at the time of the incident. In this case you would want to secure the power source supplying the charging station as a first step in mitigating the scene.
As always, be sure to use the Identify, Immobilize and Disable approach on all vehicles and assume there is a potential to be dealing with a hybrid or electric vehicle when approaching a crash or fire scene.