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Green Wheels: No easy cure for range anxiety

Researchers are looking at smaller, quick-charge battery packs and eco-efficient routing to ease the pain, but neither will solve the problem.

Published August 24, 2012

Is there a cure for range anxiety? Battery researchers around the world are striving to find out.

But developing a battery that will perform well for years and go hundreds of kilometres between charges is devilishly tricky, and breakthroughs seem far away.

So, others propose simpler solutions for electric vehicles.

Car technology writer Nicholas Brown is among those who suggest much smaller battery packs. A three- or four-kilowatt-hour unit, about one-10th the size of those in most EVs and able to recharge in just 15 minutes at a fast-charging station, could eliminate range anxiety, he says.

“Range anxiety is caused by the inability to recharge. What people with range anxiety think is: ‘If I run out of power, I’ll be stranded — or it will take eight hours (to recharge.)’ If people can recharge easily and quickly, it is not an issue for most.

“If every gas station had a few of these (fast chargers), then people could drive hundreds of miles in their electric vehicles without a problem!”

As a bonus, smaller packs would be a fraction of the cost and also far lighter — a crucial benefit since weight is a dreaded enemy of electric propulsion.

Unfortunately, this is how it would work: You’d drive 15 kilometres or so, recharge for 15 minutes, and repeat: Over and over. Even with a strong tailwind, a 70-kilometre drive down the QEW to Hamilton would require four plug-in stops totalling an hour or more.

So, on to the next plan.

Researchers at the University of California, Riverside, will test whether an EV’s range can be extended if a navigation system is able to select the most efficient route to a destination.

They’re not necessarily thinking of the quickest or shortest path. Instead, it’s the one that consumes the least battery power, explains Guoyuan Wu, the project’s lead researcher.

Internal-combustion engines get their best mileage motoring along at a steady 70 or 80 km/h. In contrast, once an EV is rolling, its power consumption increases in lockstep with its speed: There’s no “sweet spot” like the one for gasoline efficiency.

Testing by organizations such as the U.S. Environmental Protection Agency shows that rough pavement, hill climbing, hot or cold temperatures, heavy loads, and stop-and-go traffic dramatically reduce EV range. Aggressive driving is a battery drainer, too.

As a result, the actual range of vehicles officially rated at 160 km can vary from 75, under bad driving conditions and habits, to 225, under ideal circumstances and with a hyper-miler at the wheel.

Using a $95,000 grant from the California Energy Commission, researchers will drive EVs in real-world conditions over six months to collect data on electricity consumption and range in as many different conditions as possible.

From that data, they’ll create an “eco-router” that can assess potential routes to a destination and choose the one offering the optimum range.

The researchers haven’t yet acquired the two vehicles they’ll need, or assembled a team of drivers. They also have bugs to work out, including how to account for different driving styles and, in particular, the tendency of people in such tests to moderate their braking and acceleration.

They expect their research will be useful. “It should really help cut down on what has become known as range anxiety,” Wu says.

But it certainly won’t end the affliction. It’s expected to let a battery-powered car go 10 to 15 per cent farther between charges. That’s better than nothing, but not nearly good enough to be a cure.

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