Tesla has filed an interesting patent for something called “pyrotechnic disconnect”.
The use of the word pyrotechnic is probably a bit concerning, especially when it comes to electric vehicles. But in this particular application, the goal is to reduce the hazards involved with quickly disconnecting a high-voltage battery in an electric vehicle.
“In demanding applications, the disconnect must interrupt very large currents in a fast and reliable manner,” says Tesla in the patent application. “For example, the interruption of large currents has a tendency to create electric arcs, sometimes referred to as arc columns. Since the disconnect is often intended to improve safety of the electric system (by allowing it to be disconnected quickly), it is important that such electric arcs are then managed so as to not create a new hazard or risk further damage. At the same time, it is preferable that the disconnect not be overly complex or involve components that are unduly expensive.”
The device could be used in either an electric vehicle or in stationary storage, like Tesla’s Powerwall. Basically, the housing holds a combustion chamber with a pyrotechnic charge inside. Covering the outside of the housing is a busbar, which when severed, an exhaust port in the housing lets gas escape. The idea is by letting the gas escape, any electric arc created is suppressed, allowing the battery to be quickly disconnected while managing the arcs.
Discuss this story on our Tesla Forum