How Certain Tiny Explosions Keep Electric Cars Safer In An Accident

Graphic: Bosch

While it may sound a little counterintuitive, a few tiny controlled explosions can actually be a good thing if you accidentally crash your electric car. New technology from Bosch, though, could possibly make our EVs far safer in the event of a crash with a few controlled detonations.

Crashing an EV—just like owning and driving one—is a hell of a lot different than crashing a traditional internal combustion engine-powered car. An accident could dislodge battery cables in such a way that the current could leak into the rest of the car. That makes it entirely possible that the passengers inside or the rescue workers coming to help could be susceptible to a nasty shock.

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That’s where Bosch comes in. The company has developed semiconductor chips that can be fitted to the battery that will automatically disconnect in the event of an impact. Here’s a little more technical description from its press release:

The semiconductor devices are part of a pyrotechnical safety switch system, or pyrofuse. These systems “blow out” whole sections of the cable connection to the high-voltage battery by means of miniature explosive charges, thus quickly and effectively shutting off the power circulation. Bosch semiconductors play a decisive role in these systems. If, for example, the airbag sensor detects an impact, the tiny devices – measuring no more than ten by ten millimeters and weighing just a few grams – trigger the pyrofuse. This sets off little explosions that drive a wedge into the high-voltage cable between the battery unit and the power electronics, disconnecting the two. By cutting off the flow of current this way, the risk of electric shock or fire is eliminated.

Graphic: Bosch

Honestly, that’s pretty awesome. If you’re familiar with the inertia switch in ICE vehicles that shuts off fuel flow after an accident, the pyrofuse is a similar concept. It isn’t exactly reversible, though. Bosch neglects to tell us how the pyrofuse will end up reconnected post-accident, but it certainly sounds like it’ll take a little more work than hitting the reset button on an inertia switch.

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And it’s not totally foolproof, either, so don’t go thinking you can bumper-car your way through traffic in your EV. If the battery itself is penetrated—which is entirely likely if the accident is bad enough—then there’s nothing the pyrofuse system can do. You’re still at risk of a fire.

Plus, it’s still pretty hush-hush which automakers are currently using, or plan to use, Bosch’s technology, which makes it tough for both consumers looking for the safest EV as well as first responders hitting the scene of an accident to know what to expect. Hopefully that information will become available in the near future.

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About the author

Elizabeth Blackstock

Staff writer. Motorsport fanatic. Proud owner of a 2013 Mazda 2.