Power management company, Eaton, has released a battery disconnect unit (BDU) that can be combined with the upgraded Breaktor circuit protection unit to provide protection in EVs while reducing overall complexity and cost.

When paired with the Breaktor circuit protection technology, which combines current switching and resettable bidirectional short-circuit protection with fast actuation, Eaton’s BDU eliminates the need for up to 15 additional system components. Traditional systems require a combination of pyro and thermal fuses and contactors.

“As manufacturers continue to increase the power levels in EVs, it’s increasingly important to have capable and dependable protection solutions,” Eaton’s eMobility business global product strategy manager Kevin Calzada says.

“Our BDU combined with our Breaktor circuit protection technology provides everything needed, in a compact and efficient package, to protect the vehicle and occupants.”

The BDU’s primary function is to serve as an on/off switch to the battery depending on the mode the EV is operating in, such as charging or driving. Current model EVs rely on one of three traditional BDU configurations: fuse and contactor; pyro fuse and contactor; or fuse, pyro fuse and contactor, all used together in a single BDU. While all provide switching and protection functions, they each have disadvantages, including overall system complexity, serviceability, coordination difficulties and susceptibility to fatigue under high current levels.

Adding Breaktor circuit protection technology to Eaton’s BDU provides extra functionality and benefits, including active and passive actuation in a single device; the capability to transition to an off-state under a wide range of fault conditions; improved functional safety; the ability to be reset after a high-energy fault; and the ability to replace up to four high-voltage electrical components, which reduces complexity and system-level cost.