Motor Mouth: This is the battery revolution that will make EVs practical
As Marshall McLuhan might say, the car is the (structural) battery
This coming Wednesday, November 24, Driving into the Future’s latest roundtable will discuss what the future of battery production may look like in Canada. Whether you’re an optimist — you really do believe all cars will be electric by 2035 — or you think we will fall short of that ambitious mark, battery-powered cars are a significant part of our future. And if Canada wants to be part of that electric revolution, we need to find a way to become a leading manufacturer of the automobile powertrains of the future. To find out what that future looks like, tune in this coming Wednesday at 11:00 AM EDT for our latest Battery Manufacturing in Canada roundtable.
Forget solid-state batteries. All that hype about silicon anodes, too. Even the much-vaunted aluminum-air battery, which can’t be recharged at homes, isn’t probably going to shake up the electric vehicle world.
But structural batteries might.
A structural battery upends that paradigm by making the entire chassis out of battery cells. In a seemingly fantastical future, not only would the load floor be — rather than contain — the battery, so too would parts of the body — the A-pillars, the roof, and even, as one research house has shown is possible, the air filter plenum — not just be packed with batteries, but actually constructed of battery cells. To paraphrase the great Marshall McLuhan, the car is the battery.
Why would this be such a breakthrough?
More importantly, they’re heavy. As in “wide load” heavy. The basic formula used these days to calculate a battery’s energy density is that they’re capable of producing about 250 watts-hours for every kilogram of lithium-ion. Or in the acronymed world engineers prefer, 250 Wh/kg.
Do just bit of math and a 100-kilowatt-hour battery like the one Tesla squeezes into its Model S means you’re lugging around 400 kilograms of battery cells everywhere you go. And that’s in the best, most efficient of applications. It’s probably more accurate for we laymen to estimate that 100 kWh of battery weighs right around 1,000 pounds. As in half a ton.
Now imagine something like the new Hummer SUT, which is reputed to have as much as 213 kWh on board. Even if The General has found some breakthrough in efficiency, a top-of-the-line Hummer will still be dragging about a ton of battery around. Yes, it will drive farther, but because of all that extra avoirdupois, the boost in range will not be commensurate with the doubling of battery and, of course, its truck will have to have more powerful —i.e. less efficient — motors just to match the performance of the lighter, shorter-range alternative. Weight, as every automobile engineer — whether they’re chasing speed or fuel economy — will tell you, is the enemy.
Which is where structural batteries come in. By making the car out of batteries rather than adding them to an existing structure, much of that increased weight disappears. Up to a point — namely when everything structural has been converted to be a battery cell — increasing a car’s range would come with very little weight penalty.
