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EV.7.6.1 All electrical systems (both Low Voltage and High Voltage) must have appropriate Overcurrent Protection/Fusing.
EV.7.6.2 Unless otherwise allowed in the Rules, all Overcurrent Protection devices must:
a. Be rated for the highest voltage in the systems they protect.
Overcurrent Protection devices used for DC must be rated for DC and must carry a DC rating equal to or greater than the system voltage.
c. Have an interrupt current rating higher than the theoretical short circuit current of the system that it protects.
EV.7.6.3 Each parallel element of multiple parallel battery cells, capacitors, strings of battery cells, strings of capacitors, or conductors must have individual Overcurrent Protection.
EV.7.6.4 Any conductors (wires, busbars, etc) conducting the entire pack current must meet one of:
a. Be appropriately sized for the total current that the individual Overcurrent Protection devices could transmit
b. Contain additional Overcurrent Protection to protect the conductors
EV.7.6.5 Battery packs with Low Voltage or non voltage rated fusible links for cell connections may be used when all three conditions are met:
An Overcurrent Protection device rated at a current three times lower than the sum of the parallel fusible links and complying with EV.7.6.2.b above is connected in series.
The AMS can detect an open fusible link and will Open the Shutdown Circuit EV.8.2.2 if a fault is detected.
Fusible link current rating is specified in manufacturer’s data or suitable test data is
provided.
EV.7.6.6 Cells with internal Overcurrent Protection may be used without external Overcurrent Protection if suitably rated.
Most cell internal Overcurrent Protection devices are Low Voltage or non voltage rated and conditions of EV.7.6.5 above will apply.