Software wise, the power board has 2 main functions.
Over the span of 10 second the voltage that comes from the LiPo is read and averaged. After than 10 second the reading is sent to the top board to be used for control and to be sent as feedback.
With killrobot.py in basestation/python_utils all the robots can be killed remotely. There is a hardware switch on the power board which enables/disables this feature.