BMW thinks it can turn speed bumps into energy for its EVs

A new patent from BMW may unlock the energy-generating potential of one of America’s most defining modern features: a woefully inadequate and underfunded road infrastructure. 

Car enthusiast news site CarBuzz unearthed a document from the German national patent office that reveals a new suspension design, which, if developed and put into production, would allow a car to gather electricity generated from bumps in the road. 

The patent, which was independently located and verified by The Verge, could represent a new way to charge an electric vehicle’s battery through normal, everyday driving whenever things get bumpy — which, for a lot of us, is basically all of the time. 

It works like this, according to a rough English translation of the patent documents: normally, the energy from a car’s suspension moving up and down when a wheel hits a bump or a twist in the road is effectively wasted as heat energy. But the proposed setup in the patent includes a small generator, flywheel, and clutch in the suspension that acts to capture energy during this process. 

After a car’s wheel moves upward in response to a bump, the generator is engaged,  and the resulting energy is used to recharge the EV battery or a conventional 12V automotive battery. CarBuzz speculates that the system could be used on a future electric flagship model, like a BMW i7: a larger, more complex, more expensive car that suits such a feature. 

A BMW spokesman didn’t immediately return a request for comment as to whether this particular system is headed for production, but it’s worth noting that car companies file patents all of the time, and not all of them become a reality.

The idea of transforming kinetic energy from road bumps into electrical energy isn’t an entirely new one, even though this particular BMW patent was registered in May 2021 and published online in late November of this year. Back in 2016, German rival Audi announced it was developing a prototype called “eROT,” or electromechanical rotary dampers, that would also convert the kinetic energy created during the compression of the car’s suspension into electricity for a 48-volt electrical system — a “mild hybrid” setup that’s become increasingly common on luxury cars in recent years. 

However, the eROT system never went into production, and it’s unclear if Audi is still developing it today. Additionally, Utah-based company Gig Performance says it’s working on a similar technology for both heavy electric trucks and passenger EVs. 

Regardless, BMW’s patent (and Audi’s announcement from a few years ago) is a strong example of how automakers, facing ever-stricter fuel economy and emissions rules while also increasing EV range, are looking for every possible avenue to make their vehicles more efficient. For years now, BMW, Mini, and Rolls-Royce have used GPS data to map out the road ahead so that automatic transmissions can shift at optimal times to maximize fuel economy. And many modern EVs use complex route maps designed to help drivers plan out what their electric range will look like on a road trip. 

But if car companies want to harness potholes, bumps, and road damage to squeeze out more electric range, they could be onto something in the US in particular, a country that hates paying to maintain its road infrastructure almost as much as it hates to pay for rail and public transit (which it really, really hates paying for.) 

According to a report by the nonprofit Urban Insitute, in 2019, only 42 percent of America’s highway and road spending went to maintenance, upkeep, and road safety improvements, while the remaining 58 percent went to capital spending for new highways and roads. That divide has existed since the late 1970s.

Furthermore, the staggering lack of investment in transit alternatives means more cars and trucks on the same roads, inevitably leading to roadway damage and deterioration — to say nothing of traffic and pollution. 

Of course, it’s not clear yet that BMW’s patent, if implemented, would mean harsh roads generate more electrical energy than smooth ones. But if you have to deal with potholes on your way to work because you have no other way of getting there, you may as well help recharge your EV’s battery while you’re at it.