When activated, vents heat from your main weapon and prevents further heat build-up for a short period of time. (Which can be useful when using easily overheating weapons like the DLT-19X)
When in use, the Cooling Cell prevents weapons from overheating. Whenever a blaster is fired, the bar that shows how hot your weapon is will disappear almost instantly.
Cooling Cell is a great counter against Disruption, as it helps to deal with the problem faster, and makes the jamming less effective.