The Quest For an EV Fast-Charge Standard 248
An anonymous reader writes "This article explores one of the stumbling blocks currently facing EV adoption: 'Sure, there are already public charging stations in service, and new ones are coming online daily. But those typically take several hours to fully replenish a battery. As a result, the ability for quick battery boosts — using a compatible direct current fast charger, the Leaf can refill to 80 percent capacity in 30 minutes — could potentially become an important point of differentiation among electric models. But the availability of fast charging points has in part been held up by the lack of an agreement among automakers on a universal method for fast charging — or even on a single electrical connector.'"
Great Misconception (Score:4, Interesting)
Why does EVERYONE have this great misconception that EVs and charging stations are like chicken and egg?
Every time research is done into EV owner driving and charging patterns they show that people really don't drive that far on a daily basis and always prefer to charge AT HOME overnight rather than at some charging station.
Why would anyone want to drive to a charging station and wait an hour when they can just plug in when they get home? That's like having a gas pump at your house, but instead wanting to drive 30 minutes to a "gas station" to fill up.
For EV owners who have longer trips, they can take their second car, rent a car or fly.
It's too early (Score:5, Interesting)
Odds are decent that batteries are on the way out -- ultracapacitors are the candidate for replacing them. Currently (pun intended) UC's don't have sufficient capacity, but the capacity curve has been steadily rising over time, and as the stored power required for a vehicle to go a certain distance is slowly dropping, they're likely to meet sooner or later. At that time, batteries become buggy whips in search of (missing) horses.
Aside from the present position on the total energy curve, UC's offer wider temperature ranges, less toxicity, much faster charging, essentially unlimited charge/discharge cycles, have such a long lifetime compared to a battery that they reduce the disposal/recycle problem to basically irrelevant (you could probably will your UC's a few generations down the road), and present less of a fire/explosive hazard and are easily fused in array form in safe fashion. Constant voltage output is easily obtained with off the shelf electronics, and as UCs don't age the way batteries do, determining the actual charge, as opposed to an estimate, for UCs is far more easily accomplished. Current in, self-discharge rate out, current out.
This applies from small loads to large ones; In fact, as small devices become more and more efficient, as has been the trend for some time, they are walking down the curve towards practical use of UCs even faster than vehicles are.
Speaking for myself, I wouldn't invest in a Lithium Ion startup today; it looks to me like the world's worst bet. And as for connectors and standards... it's just too early. A connector designed for the relatively anemic charge rates of a Li battery would probably go up in a flash if subjected to the current inrush that an equivalent capacity array of Uc's could demand -- and limiting the charge rate to Li rates is silly. It'll take quite a connector to provide a fast, efficient charge to an UC array, but it'll *so* be worth it. Electronics that monitor the voltage drop across the connector while aware of the available contact area could maintain a safe charge rate, pushing current at prodigious rates, potentially (hah) charging the vehicle in seconds -- far faster than either fueling up with gasoline *or* charging a battery. And contrariwise, a (relative) trickle from a could also charge the UCs overnight, leading to relatively simple and inexpensive home charging stations. Bucket-brigade techniques, where the home charger trickles itself while you're off elsewhere, then is able to quickly charge the vehicle require equivalent storage in the charger itself and so are more expensive, but again, would be so worth it.
The thing is, until all this settles out -- and it is very much in flux (hah) right now -- it doesn't make much sense to standardize on anything, unless it's a trivially replaceable connector system at the charging station.
Re:It's too early (Score:5, Interesting)
Ultracapacitors currently only have about a tenth of the energy density of a battery and whether they can be improved more than two or three times while maintaining reasonable costs is far from certain.
Other than that, they're all good. Their efficiency is impressive (about 95% of electricity will end up in the motor, unlike batteries which can convert as much as 50% of it to heat during charging/discharging) and their working life makes them very attractive - current batteries aren't going to last more than a few years (much less if you're continually quick-charging them) and the e-waste millions of car batteries could produce down the line is huge.
Maybe we'll just have to get used to the idea of having a big chunk of the car space dedicated to the capacitor.