Fuses are protection devices that protect electrical circuits against undesired high currents. We can use passive fuses and pyro fuses in battery design.
- Select a fuse rated double as continuous current (e.g. initially take 400A fuse for 200A continuous current) and draw the load profile next to 50% of the fuse breaking current-time chart to check if pulse currents can be carried by the fuse without aging.
- Calculate the components and the fuse breaking energy (I2Rt) to ensure that the weakest component is the fuse.
- Identify the minimum breaking current for the failure cases when the contactor cannot switch-off.
- Analyze the short circuit clearing time and check if the contactor can withstand until the fuse breaks the circuit.
- Check the contactor-fuse coordination for normal operation, overloads and failure currents.
The fuses in a battery pack protect the battery and the other electrical components against high currents. There are special off-the-shelf components similar to 12V starter battery fuses. However, EV fuses are rated for high voltage and traction currents. The page has a list of EV fuse manufacturers.