drees wrote:...I think the main issue with the Tesla is that the motor overheats, though, not the battery pack. Which shouldn't be that tough a nut to crack - after all, ICE engines with similar output have to deal with 20 times the waste heat!...
I have seen Tesla Roadsters overheat the motor, the battery pack, and the PEM (Power Electronics Module.)
The motor and PEM are air cooled, so that is why the Leaf (with a liquid cooled motor and inverter) has some advantage there.
Even with liquid cooling, the Roadster battery can sometimes overheat because it is outputting more power, and they also have to be more careful with those laptop cells which can have catastrophic problems if overheated too much.
Note, all of these overheat conditions are monitored and managed. When a Roadster decides to stop racing due to an overheat alert it is because the system is starting to limit power because it detects that things are getting risky. So they aren't having a serious problem, but rather an intentional safety measure kicked in.
By the way, they are opposites in this way:
Roadster has liquid cooled battery, but air cooled motor and inverter.
Leaf has liquid cooled motor and inverter, but (passive) air cooled battery.
The Leaf claims to get away with no active battery cooling by having a more inherently stable and robust battery chemistry.
In a few years we can test these claims to see how well they are holding up.
By the way, newer Tesla Roadsters added another cooling fan for the PEM, and a better air-conditioner (which can cool the batteries), and better ducting for the motor cooling, so they have been making some improvements, but they are somewhat incremental. I recall hearing Tesla folks saying that the Roadster isn't sold as a track car, and it isn't a great top speed car (on the Autobahn for instance.)
Their next model (Model S) will have a liquid cooled motor and inverter which should take care of that sort of concern.