The Clarity PHEV is my 3rd EV so I’m no newbie. I see that it has a liquid cooled battery, which is great! I don’t see whether or not that system is active at all times or only when the car is plugged into a power source? Ex. If I’m parked in the hot sun with the car off on a summer day, will the TMS kick in and cool the battery?
No, because your Clarity can't know how long you will be parked. If it was parked in the hot sun for a month in an airport parking lot, its battery would be dead when you returned.
That's actually not a valid reason IMO especially on a Plug In Car. It is fair to not do this on a fully electric car (especially one with lower range) in fact this is how my focus electric operates. It must be plugged into power in order to cool the battery and will do so when the battery reaches something like 90 degrees. This is indeed due to the fact that I would be stranded if the car sat for a long period of time. However in something like a Tesla, it will kick in and cool the battery, but will stop doing so once the pack reaches a lower limit of something to the tune of 30% charge. In the Clarity Plug In, I would rather the car use the battery power to activate the cooling system in order to preserve the life of the battery. I won't be stranded because I have a gas engine as well.
It wouldn't make any difference since the system is cooled with a radiator like a car engine. It cools relative to the ambient air it doesn't use a chiller for the cooling fluid, as far as any documentation shows. There are a couple of existing threads dealing with the battery cooling system. They designed it so it would stay reasonably below the max battery operating temperature of 55 degrees Celsius, even in an ambient around 40 degrees Celsius (104 degrees F). This is at high battery output conditions, constant acceleration cycles.
