I edited this thread with a more detailed explanation of my problem:
I attached a circuit block diagram. I use a mosfet trigger switch to power the motor (high power rating => high current) for 91ms.
After that it stops directly with active braking inside the mosfet switch module.
I like to control the trigger module, and monitor the battery with a arduino.
I already tried to power the arduino directly on the battery but I think that by switching the motor off it produces very high voltage spikes because the mosfet switches the motor off.
I think I have to reduce those voltage spikes on my arduino power supply in order to protect my arduino module.
I’ve read about TVS diodes but I now how to implement them.
Maybe a snubber circuit?