Munich Electrification Unveils ME SSR to Replace Mechanical Contactors in E-Trucks
The solid-state disconnect unit switches within microseconds, eliminates arcing and offers resettable fault protection.
Munich Electrification has introduced the ME SSR, a solid-state battery disconnect unit designed to replace mechanical contactors and pyrotechnic fuses in the high-voltage systems of electric trucks and buses.
What Happened
The ME SSR serves as the central high-voltage switch between the battery and vehicle drivetrain, connecting during operation and disconnecting when parked, during servicing, or during a fault. The unit switches high-voltage circuits within microseconds without arcing and without mechanical wear. Unlike single-use pyrotechnic fuses that force vehicles out of service after a fault, the ME SSR's short-circuit protection is resettable, keeping the vehicle operational after clearing the issue. Munich Electrification describes the protection as software-defined, meaning the units are configurable, perform self-tests to detect latent faults, and produce data to predict failures before they occur. The company engineered the unit for the vibration and continuous loads of commercial vehicle operation.
Why It Matters
Mechanical contactors degrade under high duty cycles common in commercial trucking, while pyrotechnic fuses are single-use components that require replacement after each fault event. Millisecond-range response times also limit protection effectiveness in high-voltage fault scenarios. The ME SSR addresses these limitations with no moving parts, making it resistant to shock and vibration and capable of silent operation. For fleet operators and commercial vehicle OEMs, the resettable protection and predictive maintenance data could reduce unplanned downtime and eliminate the cost and logistics of replacing blown fuses after each fault.
The Bottom Line
The ME SSR comes in two variants: a standalone version that drops into existing battery disconnect units for OEMs wanting to update switching elements without full BDU redesigns, and an integrated module called Munich Electrification Solid-State Relay Next that combines switching and sensing for new platforms. The announcement provides no production timeline for either version. Timo Völkl, Munich Electrification's CTO, said the unit switches purely electronically in under five microseconds and remains resettable after every fault.
