Keeping the metals happy

Here in Canada, we have a major problem with making and using BEVs. The ambient (before windchill) temperatures here can range from –45c in winter to +48c in summer. That is a huge range to cover, and most technology is only meant for temperatures down to –25c.

Coolant can (and frequently does) freeze in the lines unless treated with special anti-freeze for low temperatures. Diesel fuel gels (and can freeze solid in extreme cases), again unless treated. Standard lead-acid batteries will freeze also.

So, how do the regular Auto makers handle this?

Most (if not all) cars in Canada have a “Block heater”. This is a 110v electric heater that keeps the engine block and lines at or above 0c, and runs from a standard household power plug. Houses and apartment parking always has a block heater outlet, as do many stores parking lots, for their staff. This is great for us EVers, as it means we can get a nice charge during the day, while parked, from somewhere other than our own house! But we still have the freezing problem.

For “water-cooled” motors and electronics, the water can be replaced with a 50:50 mix of Ethylene Glycol, which doesn’t freeze until –40c. For most purposes, this is adequate. For lead-acid batteries, however, the same won’t work. Most cars with lead-acid batteries use a “Wrap” to warm the batteries, powered in a similar way to the Block Heater, but with additional coils from the battery itself. Other battery technologies are more resilient to extremes of temperature, for example LiFePO₄ batteries don’t freeze ‘til –40c, and NiMh perform similarly. Unfortunately, both are more expensive than PbA (Lead-Acid), but they also have greater energy density. However, while newer battery technologies don’t freeze so readily, they do still decrease in current availability as they get colder.

I guess the only real option is a thermostatically controlled heat wrap for your batteries, no matter their technology. It’s a shame that such a measure will reduce (potentially drastically) the range of the vehicle in winter months, which is arguably when you need the range most. I guess I’ll have to look into a GenSet, then. Or having the batteries in the passenger compartment, which would be heated (Or cooled in summer) for both passenger and power circuitry comfort.

Thoughts? Comments? Am I completely wrong about how batteries handle the cold (Probably)? Is the heat more of a problem? Let me know!