LEAFfan wrote:I, OTH, don't want the added complexity, loss of BC, cost, and weight of a TMS. It really wouldn't help much here anyway since the car needs to be plugged in if you don't want capacity loss. When it sits all day in a 140F parking lot, a TMS isn't going to help much.
Yes, TMS would help a lot even if your car is parked out in the AZ heat all day at work anyway because in the Volt, for example:
1. If the battery still has >75% of its SOC, even if parked while unplugged, TMS is going to work to keep the battery cool if the internal battery temperature exceeds 86F.
2. Batteries designed with TMS is much better insulated than batteries that rely on ambient cooling, just because you don't want to insulate the later and trap the heat in. So before leaving for work, the TMS battery is already cooled to ideal temperature while plugged in.
3. While driving to work, any heat generated internally is removed immediately so that there's no heat build up when arriving at work.
4. Parking at work, still in the ideal temperature range in the beginning, the well insulated can stay cool for a long time before its INTERNAL temperature reaches 86F, at which point the TMS will kick in if SOC is >75%.
5. Even if the SOC is less than 75% after the first leg of the trip to work, and TMS doesn't kick in, it may still take more than half a day before the INTERNAL temperature of the well insulated battery reaches 86F and higher. And by around that time, it's already almost if not time to go home, and TMS will kick in as soon as the car is turned on to cool the battery down to as low as 72F on the way home.
If you argue that more often than not, one will not be at 75% SOC by the time one gets to work, so TMS will not kick in while parked unplugged. Then sure, but at least one has the option on a very hot day to use the ICE on the way to work to preserve the SOC to > 75% so TMS can spring into action while parked in the sun. You'd only have to do this a few times to determine how much average energy TMS will need while the car is parked. Once this is known, you can factor it in to make the most use of the battery capacity for your commute and still have enough to keep TMS running while parked. Sure, this may require the use of some gas up front to save this energy for the TMS. But at least you have that choice if you choose to use it that way.
LEAFfan wrote:The best solution, at least in hot climates is a different chemistry (sulfer added) or a different storage device such as the SC (Super Capacitor) that UCLA is working on.
Why are we even mentioning a non-existing future solution to solve a current existing issue? Even if it's the best solution, it's a non-existing solution in light of the discussion about TMS here.
Of course NOBODY wants the complexity and added cost of TMS if they can help it. But today they can't help it, and until then, the best current solution is TMS, even if you view it as a necessary evil.
When a heat-resistant battery solution becomes a reality, I'll be the first in line to ditch my TMS EV to buy a non-TMS heat-resistant EV. But I'm not going to buy a non-TMS EV TODAY that doesn't have a heat-resistant battery, which is exactly what the LEAF is today.