An electric vehicle charges at a station in Vermont on June 18, 2013.The Canadian Press
Energy advocates are recommending that electric-vehicle owners plug in their cars whenever it’s cold out and avoid fast charging – two suggestions that could further discourage Canadians from driving EVs.
“Don’t do it if you don’t need to,” says Steven Christensen, executive director of the Responsible Battery Coalition, of fast charging. “If you’re just going 15 miles to work and back, fast charging is certainly something you shouldn’t be doing because you’re going to shorten the battery life.”
The Responsible Battery Coalition, which counts academics, non-governmental organizations and automakers including Ford and Honda among its members, is issuing the advice in conjunction with a report on rechargeable battery longevity by researchers at the University of Michigan.
According to the study, which appears in the April edition of the Journal of Energy Storage, lithium-ion batteries account for 5 per cent to 50 per cent of the cost of a product, ranging from smartphones to laptops and vehicles. In EVs, they typically make up more than 35 per cent of the total cost.
Extending battery lifespans in all products will have a knock-on effect across the ecosystem by lowering the overall cost of manufacturing, the researchers say. Having longer-lasting batteries will mean that fewer will need to be made, which will also limit greenhouse gas emissions and other production polluting side effects.
Preserving EV batteries, they add, is especially important since they are expected to be repurposed once they have outlived their usefulness in cars, possibly for home or industrial uses.
Plugging in when it’s cold out – or exceptionally hot – is also wise when it comes to extending life expectancy, Christensen says.
Lithium-ion batteries tend to lose their charges in extreme temperatures, which is why EVs are equipped with liquid thermal management systems that either heat or cool them, depending on the weather.
If a vehicle isn’t plugged in when it’s cold out, the system draws stored power from the battery itself to keep the battery warm so that it doesn’t lose its charge. When the EV is plugged in, the management system instead draws power from the electricity grid, which alleviates some of the strain on the battery and helps preserve its durability.
Fast charging, meanwhile, also degrades batteries faster than standard charging. Christensen says that fast charging is inevitable and desirable for drivers when they are on longer trips, but they should opt for slower methods whenever possible, such as when they are at home or at work.
Some consumer behaviour experts have expressed concern over whether drivers will be able to heed the suggestions, and say that they might act as further disincentives to buying EVs – especially in Canada, where winters can be long and cold.
EVs have already been shown to exhibit lower range in cold temperatures – tests by the American Automobile Association last year, for example, found they can be up to 40 per cent lower than in fair weather.
Asking drivers to plug in when it’s cold and to avoid fast charging both require engaging in what psychologists call implementation intention, or a strategy of thinking, “if this happens, then I need to do that.” They’ll need to think about the location of plug-in stations, how much range they have and how long it’ll take to recharge.
“You almost have to plan your day around it,” says Katherine White, a professor in the marketing and behavioural science division at the UBC Sauder School of Business at the University of British Columbia. “It’s not necessarily intuitive.”
The problem is compounded, she adds, by the fact that many consumers don’t think long-term when it comes to their purchases. With EV batteries, there’s an element of “temporal discounting” involved, where immediate rewards are preferred to those that may accrue in the future.
“It’s very abstract and in the future,” White says. “That’s hard for people to think about.”
Olivier Trescases, a professor of energy systems at the University of Toronto who is conducting research on how to repurpose EV batteries for secondary uses, agrees with the suggestions but also acknowledges it may be difficult to get drivers to follow them.
Fast-moving technology means consumers aren’t likely to worry about the long-term effects of how they use their EVs.
“By the time your battery degrades to an unacceptable level, you’re probably going to go to a new car and that battery will be reused in a different application,” he says. “But it should be known that fast charging accelerates the aging of the vehicle.”
On the bright side, he adds, those same technological advances may help counter some of the inertia with consumer tendencies.
EVs with wireless connections can automatically send reminders to owners to plug in their cars when it’s cold out, for example, while intelligent battery-managements systems can automatically decide what charging speed to use, depending on location and situation.
Christensen doesn’t believe his group’s suggestions will act as disincentives – they are merely reinforcing the advice provided by automakers.
“This is in the owner’s manual. You just have to get people to read the owner’s manual,” he says. “The folks who built that battery know it very well.”
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