Aptera's FAQ Spreadsheet says "we may use liquid cooling but are testing to see if we can just convection cool to save weight."
That came up 2/27 on a different forum thread "Cheap Body Repairs" where on 3/1 OceanDragon wrote:
"The Leaf battery is air cooled, the entire bottom metal pan is also cooled passively with air flowing over it. The mounting flanges are bolted to the metal frame of the car which acts as a passive heat-sink. The newer Leaf batteries add to the air cooling with 2 active fans which augment the airflow through the channels. What do you think of Aptera's battery arrangement sitting inside of a composite insulated shell? It is supposed to be filled with resin. Imagine a warm sandwich inside of a Yeti cooler. I think that arrangement is going to be worse than the Leaf's since there is no radiant or convection heat loss. I am also concerned the passenger temperature with the heat being pumped throughout the shell to cool the motors, and inverter. Add to this the trapped heat from the batteries and the air conditioning condenser. That is going to be one warm passenger compartment. I wish they would add a small condenser in the rear wheel well. It shouldn't cause too much disturbance in the airflow. Even the Porsche 'trombone tube' tucked into the inner right fender well should help Aptera's design."