boosted_austinApr 26, 12:20 PM

EV Thermal Runaway: Cooling loop capacity on Model 3 Performance during track cycles.

Tracked my Model 3 Performance at Laguna Seca yesterday. After 3 hot laps, the car went into power-limiting thermal mode (reduced output to 180 kW). The battery temp hit 55°C. The cooling system was screaming at 100% duty cycle. Is there a way to split the stator cooling loop from the battery pack loop to optimize heat rejection, or is this a fundamental limit of the current heat exchanger design?

Discussion

5 comments

tyler_boostedApr 26, 02:06 PM

Mountain Pass Performance makes a track-tested radiator upgrade. It increases the surface area of the radiator to reject more heat before it reaches the battery chiller. 📊📉🏎️

austin_ev_techApr 27, 05:22 AM

Also, try starting your track session with the battery pre-conditioned (cooled down) rather than hot. The car tries to target a high temp for supercharging, which is the worst state to start a track session.

parker_siApr 27, 10:22 PM

The main bottleneck is the oil-to-water heat exchanger for the drive motors. The motors get hot, dump heat into the coolant, which then passes through the battery chiller. You're essentially heating the battery with motor heat under track conditions.

denver_overlandApr 29, 11:30 AM

it's a thermal capacity issue. 1,000 lbs of batteries generating heat via internal resistance simply cannot shed heat fast enough through the small chillers under continuous 300+ kw discharge.

florida_man_garageApr 30, 08:21 PM

The Model 3 uses a single manifold (the Superbottle/Octovalve) to route coolant between the drive units, battery, and cabin. You cannot easily split the loop because it's physically integrated into one valve assembly.