Cold weather hurts batteries. We know this. But why? Well, About.com pretty much just tells us that chemical reactions slow down as the temperature drops, so a chemical battery will produce less current when it's cold. For more understanding than that, please see your local continuing education facility's chemistry adviser.
This is one thing that gives me pause about electric cars. I wonder how well they'll perform in regions of the country that experience what I will understate as "Proper Winter". Your car is hard to start in the winter because the battery doesn't like the cold. After it starts (if you're lucky), you're fine, because the gas motor inherently produces heat as a by-product. your car will warm up to proper temperature in a couple of minutes and be perfectly happy... so long as you can get it started with your battery. So what happens when your whole car runs on batteries? For one thing, I'd imagine the range of travel would suffer horribly.
The other thing you'd miss is the free heat. Gas engines produce heat. They can't help it. In the summer, this is a pain, since you're hot enough already, and keeping your engine from overheating becomes a priority. But in the winter, your car's cabin heater works by borrowing a little heat from the engine and using that to heat up the passenger compartment, which is fine, because your engine produces more heat than it knows what to do with. If you weren't using it for your comfort, your car would just be throwing it out the window. So, yeah, free heat. That's why you can't warm up until the engine starts to warm up. Well, with an electric car, there's no free heat. If you want to be warm, you'll be draining the batteries faster. Also, remember that generating heat with electricity is really inefficient. Ever lived in an apartment with electric baseboard heaters? I have. The energy bills were insane. Warming up the passenger compartment in your electric car will seriously kill the batteries.
So, yeah, in my opinion, the jury is still out on electric cars because of the power source, if you live in a sometimes-cold place. Batteries need to get smaller, stronger, cheaper, lighter, and quicker. Right now, most decent batteries on the market are lithium-ion, but there's a better kind on the horizon: lithium polymer. Lithium ion batteries are still made with mostly heavy metals. This makes them heavy (duh). It's possible to replace some of the heavy metals in a battery with polymers. That means plastic, which is lighter than metal (also duh), and I believe they have greater energy density than LI kind.. Right now, there is a lithium polymer presence in the consumer market. Radio control hobbyists will be familiar with LP batteries. Those wee little R/C helicopters? Those generally run on lithium polymer batteries because they're light enough and powerful enough to make a model fly. However, it will be a while before LP batteries take over the broader market, probably because there aren't enough of them produced to feed broad-based consumer products like cell phones and cars. Even so, LP batteries will still suffer from the cold. I suspect that hydrogen fuel cells will endure the cold better than conventional batteries, but I'm not sure about that.
As for this Owens-Corning ad, they seem to think it's important to have your battery insulated with "Fiberglas". Don't be fooled. A battery at rest doesn't have any "body heat" to be retained by thermal insulation. So, the wintry imagery in this ad is misleading. I suspect the kind of insulation they're talking about here is electrical insulation, keeping the various bits inside the battery from making contact and shorting out. The ad copy just mentions holding "the power-producing material on the plates longer", for longer battery life. That doesn't sound like it has anything to do with hot or cold. I could be wrong, however, since my field isn't chemistry. Maybe some super-smart reader can straighten me out, if I'm completely off base.
In the meantime, thank you, Advertising, for not only assuming everyone is ignorant, but actively working to keep us that way. I knew I could count on you.
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