Recently a team from Penn State university published their research on how to change an electric vehicle battery with 200 miles of range in just 10 minutes. Their approach involves heating the battery up to about 60 degrees centigrade, which reduces the amount of metal plating that happens inside the batteries – and damages them – during fast charging. This is not a yawn, as faster charging technology is actually pretty useful, and will also be useful in things like laptops and phones, though you will need them to cool down before touching them. Other high-speed charging techniques – some of which require new batteries and some which just require new chargers – have also made excitement in the lab.
The first caveat is that demonstration of something in a lab is a long way from it being deployed at scale, or even being demonstrated to deploy at scale. Nonetheless, some fast charging approach is going to come and deliver performance like this in the coming years.
More pointed is the fact that much of the excitement of this technology comes from people who imagine electric cars are like gasoline cars, which you drive around and then fill up at a filling station once they’re near empty. Filling up with gasoline takes 4 to 10 minutes (most spent diverting to the station or in line) so if electric car charging takes not much longer, we can start thinking in the terms we used to think in when we all had gasoline cars.
The reality is that most people who have purchased new generation electric cars which can drive 200 miles on a battery take zero time to recharge their car when driving around their town. The only time they wait to charge on it is on long inter-city road trips – where they will definitely like this fast charge.
Most (though not all) EV owners install some charging at home. Once you do this, you always charge while you sleep. Every night. You take a moment to plug in and unplug (and not even a moment for those few who use inductive charging) and then it takes none of your time. You don’t drive an inch out of your way. You don’t hunt for the cheapest gas or even pull off the road to a corner station. You don’t wait in line. It all happens when you sleep, when you don’t care if it takes 10 minutes or 10 hours. Making it faster has very little extra value.
Some EV owners don’t charge at home, because they don’t park in a driveway or garage. For most of them, the best choice is charging at work, which often comes free. It may involve having a limited selection of parking spaces, and hassle if there are not enough chargers, but you don’t drive out of your way or spend your personal time charging. This is definitely the 2nd choice, but it’s the only choice for many of these folks. One big issue is you don’t recharge on the weekend, so if you want to do a weekend of very heavy driving you might look at the 3rd alternative.
That 3rd alternative is public charging stations, in particular fast charging stations. Today those take 40 to 80 minutes to charge up your car, which is not good at all, and if you use these, you would obviously love to do it in 10 minutes. But at least today (years before extreme fast charging might arrive) I consider this approach as “doing it wrong.” It should be the backup plan if something goes wrong with home or work charging, not the main plan. Today’s fast charging is harder on battery health and should not be the main approach. For now, EVs work best for those who have a home parking spot they can wire up. That’s not everybody, but EV adoption is still pretty small. Fast charging stations are the answer on long road trips. 10 minutes is almost as good as gasoline, though they tend to be out of the way, raising the time to a more annoying 15-20 minutes. This is a long time to wait but not enough time to eat a meal, which is what people do when it takes 45 minutes.
The 4th alternative is to use public slow (Level 2) charging stations, the kind you find in parking lots or in “electrification” projects. Even when these are free, they generally are of minimal use, unless they are at places you will spend a lot time, like workplaces or especially hotels you are sleeping at. Much of the focus on installing charging infrastructure has revolved around these stations which are useless to owners of long range EVs.
In the more distant future, as EV penetration gets very large, this story will change a bit. Above a certain level we need to start moving some EV charging to the day to take advantage of solar power. Much less of that can be done at home, and workplaces become the natural place, particularly companies with on-location solar. If the price of daytime power becomes cheaper than night (today it is much more expensive) robocars will also travel during the day to grab power when it’s cheap. Daytime charging at high speeds is more valuable because cars don’t sit still for nearly as long in the day.
Fast charging that doesn’t hurt the battery will be useful in the way cars charge in the future, which is by driving themselves to the charging station, where they can either plug in using their own robotics, or human charge jockeys can plug them in for a small fee. Today, a Tesla can’t quite handle slow moving in a parking lot, but we’re actually not that far from it being quite reasonable for cars to both reposition themselves in employer parking lots or other charging lots, or even drive a mile or two in the middle of the night on empty roads at slow speeds to get to charging. When this is available, you don’t need to have charging at home or work or even in hotels. Let the cars worry about it at night. Which is even easier than plugging in at home.
Source: forbes
