Smart switch protects 800V battery packs

The smart switch
(Image courtesy of Kyocera AVX)

Kyocera AVX has developed a smart semiconductor switch for EV battery pack designs, writes Nick Flaherty. The switch supports voltage levels up to 930 V for 800 V battery packs and is able to withstand short current events up to several thousand amps. Using a scalable design, the switch can be adapted to different power classes up to 640 kW continuous performance and provides both a safety cutoff and also support for higher charging rates.

The high requirements and increased integration of additional safety-relevant features in the vehicle electrical system architecture mean a semiconductor-based design can provide marked advantages when compared to a mechanical relay, including considerably higher switching speeds.

Particularly in the event of a short circuit, every microsecond counts in order to guarantee a safe disconnect. The Kyocera AVX Electrical Smart Switch protects the supply circuit during charging and discharging bi-directionally in the event of overcharging or in the event of a short circuit. In addition, the Electrical Smart Switch permits the pre-charging of the DC network to enhance the service life of system components.

In the event of a short circuit, the electrical smart switch turns off in a few microseconds and thereby may prevent severe damage to the supply circuit. Inrush current peaks can be prevented by using the implemented pre-charge function. Using this function the current is limited by pulsing with a frequency up to 100 kHz and thereby is another important gain made whereby overall system costs can be lowered.