MSXIV: Four methods for cooling the pack was discussed: Liquid Cooling, Phase Change Interstitial Material, Forced Air Cooling, and Conductive Cooling to catamaran. Of those four options, Forced Air Cooling was chosen; Liquid Cooling and Phase Change Interstitial Material were thought to be more superior in terms of performance than Forced Cooling, but they were either way too complicated and risky to produce or unable to be acquired. Conductive Cooling to Catamaran would simply be ineffective due to the terrible thermal conductivity. Battery Pack Cooling
According to this page Specific Heat Capacity of the Battery Pack, it is calculated that the system with the use of the Noctua NF-F12 iPPC 3000 fan could provide “enough cooling power to keep the pack at a maximum of 45 degrees given our worst case conservative estimates.” However, the problem faced here is that “the cooling and temperature distribution within the pack is NOT uniform” as you can see from the diagram below.
The cause of the problem here is that the not much air is flowing through the middle of the pack, causing the interior cells to heat up 10-15 degrees more than the exterior cells. The possible solution proposed by Micah is to “move the cells further apart in the middle in order to get more airflow through the module, essentially creating an airflow channel within the pack.” The MSXII took similar approach, as “fans [were] mounted inside the box and air will flow along the length of the box.”
Battery Pack Temperature Distribution - adjusting cell spacing
Testing - Cooling Methods and Temperature Distribution under High Loads
TESLA: On the other hand, Tesla has chosen Liquid Cooling by developing a system called BMS (Battery Management System). The way the BMS cools individual batteries is to make a ribbon like pipe snake through the battery pack so that it contacts with each and every cell, as you can see below.
In order to prevent the tube breaking and leaking the coolants, Tesla has chosen to use metallic inner tube, and Glycol flows through the tube as the coolant.
And here's full Model S battery module.
Information for this paragraph was taken from here:
https://www.easyelectriccars.com/why-do-tesla-batteries-not-overheat-teslas-battery-cooling-system/