Scientist explains how a mix of hybrids can lower emissions more quickly
Says we simply don’t have enough lithium to go all-EV
An EV-only lineup is the wrong way to curb emissions, says Toyota’s Chief Scientist. He says that new data shows that it’s a mix of hybrids that will help lower fleet CO2 emissions rather than the long-range big-battery electric cars we’re starting to see take over the industry.
“Time will show that our point of view is actually the correct one,” Toyota Chief Scientist Gill Pratt said at a roundtable in Tokyo (via Automotive News). “One way or the other, there will be a diversity of powertrains used throughout the world.”
The math is based on the current scarcity of lithium. The metal is a key part of current electric vehicle battery cells. There’s also not enough to go around, at least not yet. Pratt says that using it sparingly can lower CO2 more quickly.
His model starts with a hypothetical fleet of 100 internal combustion engine vehicles that each average 250 grams of CO2 per km driven. For reference, that’s about the emissions of one large crossover.
He then assumes a limited amount of lithium. Enough to make 100 kWh of EV battery cells. That’s only enough for one long range battery in a similarly large vehicle. If all of that lithium was put into one vehicle, total fleet carbon emissions would drop by only 1.5 g/km.
If the same lithium was used to build 90 1.1 kWh hybrid batteries, the fleet would have 90 hybrids and 10 pure ICE vehicles. The fleet average emissions would drop to 205 g/km, he says.
Because there is only so much available lithium, Pratt’s reasoning goes, it is better to spread it around. The idea also offers some potential efficiency improvements, as large-battery EVs use much of their energy just to move around that massive pack. The Hummer EV’s pack, for example, weighs nearly as much as a Honda Civic.
The numbers, of course, greatly vary based on the vehicles involved. Toyota’s own Highlander, for example, drops from 231 g/km to 158 in hybrid form. The Tundra pickup, however, sees emissions fall by just 9 g/km to 274 in hybrid form.
But the model is why Toyota is moving ahead with more hybrid models even as competitors go all-in and announce planes to only sell electric vehicles. Toyota, instead, expects to sell 5.5 million hybrids and PHEV models per year by 2023, double its current global total.
Pratt compared today’s EV enthusiasm to the recent confidence in autonomous driving. In 2018, multiple automakers claimed they would be selling fully autonomous vehicles by now. Today, none are.
He said that a lack of charging infrastructure and that shortage of lithium will create a bottleneck that will hurt the mass-market roll-out of EVs over the next decade.
