OEM Automotive Fuse Links for EV / Plugin / HEV / FCEV​

Pure EV and Plug-in Systems:They are fully battery powered,usually by a 32kWh to 64kWhtraction battery and auxiliarypower unit. The fuse for these electrical circuits hast towithstand high currentfluctuations, constant chargingand discharging, high operational temperatures, current overloadscenarios and high short circuitcurrents with interrupting rating up to 20kA.

HEV Systems: In a hybrid systemthe battery pack is usually smaller,ca. 10kWh to 20kWh and operatesat lower voltages 200-450 Vdc.Harsh acceleration and chargingis generally managed through theICE and regenerative braking withmoderate load and effect on thefuse life cycle. Nevertheless, current overload situations andhigh short circuit currents withinterrupting rating up to 20kA arecritical for selecting the correctfuse.

HFC-EV Systems: Acombination of hydrogen fuel cell and battery pack produce theelectric power, whereas theamount of energy stored on board is determined by the size of the hydrogen tank. Therequirements on nominal currentratings as well as interruptingratings up to 50kA are usuallyhigher than in EV and Plug-insystems.

The formula for current rating of an EV fuse is based on Ib: Ib = In x KT x Ke x Kv x Kn x Kc

Converted to : In ≥ Ib / (KT x Ke x Kv x Kn x Kc)

In: rated nominal current of fuse

Ib: the allowable maximum continuous load current in the circuit, determined by operation current of the application

KT: temperature derating factor, determined through measurement of theambient temperature

Ke: heat transfer derating factor, determined through the cross section of the terminal connection

Kv: cooling correction factor, when additional cooling measures areemployed

Kc: cyclic loading factor, basically the ’premature aging’/ fatigue factor of the fuse due to to heavy mechanical stress from current over-loadfluctuations