Fast charging – we have the battery. Now we need the charging system.

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A US firm claims that they have developed a new EV battery that can be charged to give 240 miles of range in just 5 minutes. This means you can charge an EV as fast as you can diesel or petrol car for the same distance. There are problems with this as we will see…

New battery technology

California based Enevate claim that they have developed a new EV car battery that can be charged in just five minutes. Founder & chief technology officer of Enevate Dr Benjamin Park said, “Extreme fast charges for very short and convenient charging times, higher energy density leading to longer driving ranges, and cold temperature operation with inherent safety advantages make this technology ideal for electric vehicles.”

Range anxiety

Up until recently, internal combustion engine (ICE) drivers have long been able to argue that you can’t charge an EV up as fast as you can an ICE car. I’m a long-distance driver – around half the journeys I do will be up and over 200 mile round trips. On a run from Dorchester to Luton I might be lucky to “charge my diesel car” once for the round trip.

Today I’d have to take a very long time to do the Luton run in an EV by comparison to an ICE car. In a BMW i3 I might have to spend an hour charging the car at Fleet Services on the way up, and after a night’s charge do the same midway home. A Chevy Volt might get me 200 miles or 2/3rds of the basic journey without the miles of travel I do in Luton seeing friends. For argument’s sake I’d need one full charge for the trip, and even then the battery would be on red when I got home. A battery capable of taking an ultra-fast charge would make the Chevy Volt run competitive with the diesel I drive today.

Charging technology problems

Current batteries used in cars today could overheat or explode if you whacked in a massive charge. The breakthrough by Enevate has been in changing the battery chemistry so the battery won’t do this. There are still major issues to tackle.

Reporting on Tesla’s new liquid cooled Superchargers in 2015, ChargedEVs reported, “There’s only so much power you can push through a conductor of a given diameter before the cable heats up and melts.”

On a LinkedIn discussion I saw, someone argued against the Enevate system, “240 miles ~ ca. 90 kWh and this in 5 minutes. (=1/12 h) needs a 1080 KW charger = 1 MW charger. If just 1% of the charging energy will be transformed in heat, you must cool for 10kW heating. This corresponds to about 5 ovens at full capacity.” The heat you will experience from a non-cooled ultra-fast charger would be the equivalent of five kitchen ovens on full whack or a combined heat of in excess of 1250 degrees C. Never mind the skin on your hands, that sort of heat could start melting the car itself.

While new cooled ultra-fast systems are being tested such as the CCSplus system, it will be a while before we see a safe and efficient system of this kind.

Another issue is the sheer current necessary to charge the vehicles. If 500 EVs were asking for a Megawatt each of power, you would need some serious amounts of power available on the grid or it would be lights out for the rest of the grid for miles around.

Other more positive battery technologies

Battery technology is getting exciting these days. In just a few years’ time we will see very different EVs on the road. While 150 mile ranges may be typical today, 300 miles will be typical in the next generation of cars with much the same weight of battery. It won’t be long before you will see cars capable of 4-500 miles from a night’s charge. That means your average commuter may only need to charge their car once a month, and even people like me who only drive decent distances won’t have a worry. It’s my belief watching what the experts have to say that range and not speed of charging is going to be the way forward.

 

Richard Shrubb

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