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An EV makes a great second car in Canada but the long distances and cold weather are problematic for current EV technology. Hopefully that improves relatively s

An EV makes a great second car in Canada but the long distances and cold weather are problematic for current EV technology. Hopefully that improves relatively soon.

sandworm101 4y ago
LoL. Don't worry. Global warming will deal with the low temperatures.
- ben_w 4y ago
  Toronto climate, average low, January: −6.7 °C (19.9 °F) Temperature change needed for complete loss of Greenland ice sheet: between 1 and 4 °C. (That's a change by, not a change to). Effect of complete loss of Greenland ice sheet: 7.2 meter sea level rise.
  - sandworm101 4y ago
    Torono isnt really typical. It is southern canada, and a bit of a heat island. Fort Mcmurray (that had to evac a few years ago) average january low: -22.5c. Places like that have almost 90c temperature swings from low to high in a given year (-50 to +35).
    - ben_w 4y ago
      The Toronto region contains about 25% of the Canadian population, which is sufficient for my point. Your attempt at nit picking, if it were valid, would actually makes it much worse: a temperature increase sufficient to turn "-22c" into "we don't need to worry about cold batteries" requires close to double the difference between today and the highest estimated average global temperature ever in the biological history of the planet, and that temperature happened before trees had evolved. For example, naïvely adding 22 C (22.5 says Wiki) to the average so that the coldest was no longer below freezing, your Fort McMurray would have a new July average high of 46.2 C, which is above the current average of Death Valley 10 months of the year and pretty close the other two.
elihu 4y ago
I think the solution for batteries in cold weather is to insulate the pack and heat the battery "coolant". Almost all modern EVs use liquid cooling of some kind. (Nissan Leaves are the exception; I don't know if they've added that in newer versions, but it's why Leaf battery packs were notorious for wearing out quickly.) I don't know if battery heaters are a common feature on current EVs. I'd think it would be particularly useful for LFP cells, which can be damaged if you try to charge them when they're below freezing. They can be discharged safely (if not efficiently) at much lower temperatures, which means you could "bootstrap" the car in cold weather by using the battery to heat itself until it gets warm enough to charge (without which you can't use regenerative braking). It wouldn't be that far-fetched to imagine a battery cell with a built-in heating element (e.g. an internal 1 ohm resistor across the battery terminals) that, when activated, keeps the cell at at least room temperature and shuts off when the battery gets up to temperature. Normally you'd only activate the heater when charging or driving.
- osigurdson 4y ago
  Resistive heating using a battery offends my sensibilities. It takes beautiful low entropy energy and irreversibly converts it high entropy heat.
  - elihu 4y ago
    I can sympathize with that, but if the choice is between, say, using 1% of the battery capacity to heat the cell versus losing 25% of the capacity because they just don't work efficiently in the cold, going with the 1st option seems like the right move. Although maybe that's not right... if a large amount of energy is "lost" when the battery is too cold, that energy has to go somewhere. If it ends up as heat anyways, maybe it's really functionally equivalent to having a heating element in the cell. In which case the solution is probably just to insulate the batteries better.

An EV makes a great second car in Canada but the long distances and cold weather are problematic for current EV technology. Hopefully that improves relatively soon.

sandworm101 4y ago

LoL. Don't worry. Global warming will deal with the low temperatures.

ben_w 4y ago
Toronto climate, average low, January: −6.7 °C (19.9 °F) Temperature change needed for complete loss of Greenland ice sheet: between 1 and 4 °C. (That's a change by, not a change to). Effect of complete loss of Greenland ice sheet: 7.2 meter sea level rise.
- sandworm101 4y ago
  Torono isnt really typical. It is southern canada, and a bit of a heat island. Fort Mcmurray (that had to evac a few years ago) average january low: -22.5c. Places like that have almost 90c temperature swings from low to high in a given year (-50 to +35).
  - ben_w 4y ago
    The Toronto region contains about 25% of the Canadian population, which is sufficient for my point. Your attempt at nit picking, if it were valid, would actually makes it much worse: a temperature increase sufficient to turn "-22c" into "we don't need to worry about cold batteries" requires close to double the difference between today and the highest estimated average global temperature ever in the biological history of the planet, and that temperature happened before trees had evolved. For example, naïvely adding 22 C (22.5 says Wiki) to the average so that the coldest was no longer below freezing, your Fort McMurray would have a new July average high of 46.2 C, which is above the current average of Death Valley 10 months of the year and pretty close the other two.

elihu 4y ago

I think the solution for batteries in cold weather is to insulate the pack and heat the battery "coolant". Almost all modern EVs use liquid cooling of some kind. (Nissan Leaves are the exception; I don't know if they've added that in newer versions, but it's why Leaf battery packs were notorious for wearing out quickly.) I don't know if battery heaters are a common feature on current EVs. I'd think it would be particularly useful for LFP cells, which can be damaged if you try to charge them when they're below freezing. They can be discharged safely (if not efficiently) at much lower temperatures, which means you could "bootstrap" the car in cold weather by using the battery to heat itself until it gets warm enough to charge (without which you can't use regenerative braking). It wouldn't be that far-fetched to imagine a battery cell with a built-in heating element (e.g. an internal 1 ohm resistor across the battery terminals) that, when activated, keeps the cell at at least room temperature and shuts off when the battery gets up to temperature. Normally you'd only activate the heater when charging or driving.

osigurdson 4y ago
Resistive heating using a battery offends my sensibilities. It takes beautiful low entropy energy and irreversibly converts it high entropy heat.
- elihu 4y ago
  I can sympathize with that, but if the choice is between, say, using 1% of the battery capacity to heat the cell versus losing 25% of the capacity because they just don't work efficiently in the cold, going with the 1st option seems like the right move. Although maybe that's not right... if a large amount of energy is "lost" when the battery is too cold, that energy has to go somewhere. If it ends up as heat anyways, maybe it's really functionally equivalent to having a heating element in the cell. In which case the solution is probably just to insulate the batteries better.