a: coolant loop
b: refrigeration loop
R101: Battery heater
A9/6: refrigeration compressor
Sadly, this diagram is missing the heat exchanger between the two loops. It sits in the battery coolant loop with the M43 pumps.
@Blaine: Where did you get those numbers for the activation threshold temperatures from? I've long been trying to find that information! The lower one is hard to observe, unless you want to spend the night outside in the dead of winter. I'm sure the upper one is wrong - I have never been able to observe the compressor turning on to cool the battery, and it frequently gets a bit above 30C in the summer.