When it comes to bench-racing electric vehicles, the kilowatt-hour is king. And over in Switzerland, there's an EV that will make Tesla's P100Ds look positively puny. But this is no carbon-fiber hypercar, and it's never going set any records for 0-60 times or the standing quarter. No, this is an altogether more practical creation that's meant to work for a living. It's a Komatsu quarry truck that's being modified by Kuhn Schweiz and Lithium Storage, weighing in at almost 50 tons (45 tonnes) and powered by a whopping 700kWh battery pack.

The e-Dumper has been in the works for a couple of years now, during which time its battery capacity has grown from the original 600kWh to what is now the equivalent of seven top-of-the-line Teslas. The cells in question are nickel-manganese-cobalt, 1,440 of them in total, weighing almost 10,000lbs (4.5 tonnes). And once the team has found space in the chassis for all of that energy storage, the idea is for the e-Dumper to spend the next decade trundling between a Swiss cement quarry and the Ciments Vigier works near Biel.

Here's the really cool part: each round trip actually generates electricity. Because the e-Dumper goes up the mountain empty and descends carrying 71 tons (65 tonnes) of rock, it captures 40kWh on the way to the cement works via regenerative braking. But climbing back up to the quarry only requires 30kWh, so every trip will feed an extra 10kWh into the local electricity grid. Not bad when you then consider that the e-Dumper will be doing that trip 20 times a day.

Of course, this is still an experimental project, and Empa (the Swiss Federal Laboratories for Materials Science and Technology) is working with the e-Dumper team to study battery performance in such a harsh environment and use case. Empa's battery expert, Marcel Held, says that a big question is what happens if there's mechanical damage to the cells—a real possibility in an environment like a quarry.

"Some batteries start smoking, others burst into flames," he said. "The crucial thing in this instance is to make sure the neighboring cells are not damaged by the fire and heat. Otherwise, there is the risk of a chain reaction."