Assume you mean peltier effect cooling?
We do have a cooling system on our generation 7 machines. It is not Peltier however, although it is forced air with nothing external coming in to avoid any moisture ingress. On an autonomous system in the field, it is unacceptable for computing to run hot as it can slow down the speed with which your perception layer processes obstacles/the world around it. These are designed to run in up to 120F conditions in areas like Coachella, hence the importance of cooling.
Each one has a big CPU, GPU, modem, RTK GPS, 12 cameras, 11 other sensors, expansion for further cameras and autonomy attachments to be added on also, so we've had to really go a bit overboard to make sure we have a good safety factor for heat.