hofer powerTec’s battery disconnect unit for electric buses enters series production

hofer powerTec, part of the hofer technology group, has started series production of a battery disconnect unit (BDU) with integrated control functionality, built for an electric bus application. The unit is going into a new battery system developed by LION Smart, which is intended for use in commercial vehicles, particularly buses.

A BDU is the high-voltage interface of a battery pack—it contains the main contactors, pre-charge circuit, fuse and current sensing unit that connects and disconnects the cells. The pre-charge path limits inrush current into the inverter’s DC-link capacitors before the main contactor closes, and contactor weld detection is commonly handled at the same point.

Integrating the control electronics into that assembly can allow designers to eliminate a separate controller and its associated wiring. Bus battery packs are usually distributed in roof or underfloor modules, and the space left for disconnect hardware is limited.

The architecture supports multi-pack systems at over 1,000 V.

hofer also offers the iBDU, or intelligent battery disconnect unit. The iBDU routes high-voltage lines separately, which hofer says allows early detection of thermal instability. It also offers Automotive Safety Integrity Level (ASIL) capability.