Hey! Sorry for the weird heading. I live in a country where EV’s are everywhere and I keep hearing debates about the need and possibility for range increase. Today I overheard a discussion between two people about batteries in the near future.
Person A argued that the range increase and battery improvememts in EVs have been so great the last 10 years and this is indicative of it being a technology that will just keep on improving – and we just have to have some patience before the batteries and range will improve even more.
Person B argued that while thats true, a lot of the range improvememts now aday are due to more aerodynamic cars and that seeing as a battery is a chemical process, we are closer and closer to hitting the limit of batteries without any significant scientific breakthrough.
Im fairly uneducated in this field and find it hard to evaluate whos right. Person Bs arguements seemed more trustworthy, but it doesnt mean that hes right.
So my questions are: Who’s “right” and why? Will batteries in EVs keep improving significantly or have we already seen the biggest improvememts?
Thanks a lot in advance!
In: Chemistry
It is very hard to predict the future. We can only extrapolate from the past. But this does not tell us if there is a major breakthrough right around the corner. Firstly the aerodynamic performance of car have not gone down that much. In fact depending on how you measure it the aerodynamic drag on cars are just going up as the cars are getting bigger. It is true that the coefficient of drag goes down, although we have pretty much gotten it perfect for the last ten years. But the coefficient of drag is only about the shape, not the size, of the car. You can easily decrease the coefficient of drag by increasing the size and increasing the drag.
As for battery technology this is often measured in energy density, how much energy a single kilogram of battery can hold. And for lithium ion batteries the energy density have gone slightly up but not significantly. The battery cells you got in your 20 year old laptop is pretty much the same as the battery cells in your new electric car. There are just slight improvements, nothing revolutionary. The big difference though is the price of batteries. While lithium ion batteries were so expensive that we could only afford small ones for laptops and cell phones, and for small batteries in hybrid cars, we can now afford large battery packs in fully electric cars. The main difference between electric cars with different ranges is the size of their battery. And due to increased weight you need to more then double the size of the battery to double the range.
We are therefore reaching kind of an impasse here. In order to increase the range as much as possible electric cars are becoming heavier and heavier. We now see electric cars being sold weighing more then three tons. And the range is not increasing much with the weight since heavier cars need more energy to overcome tyre friction. While we are still seeing some improvements in the technology there is nothing on the horizon that will make the range improvements sustainable. Instead what we might be looking at is more charging stations and faster charging. Today you might have to stop for 10 minutes every 3-4 hours to charge the car but if we can reduce this to less then 5 min it would be far more convenient to take long trips.
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