LEM, a supplier of electrical measurement solutions, has introduced a new current sensing unit designed for electric vehicle (EV) battery management systems.
The Hybrid Supervising Unit (HSU) combines shunt and open-loop Hall effect technologies in a single component — a first on the market. It addresses key requirements for compactness, cost-efficiency, and functional safety in EV battery systems.
The high-voltage battery management system (BMS) in EVs is responsible for monitoring the state of charge and state of health, ensuring safety, and performing cell balancing.
Traditionally, achieving higher safety levels has required two separate components: a shunt for measuring high currents (up to 2000 A) and a fully isolated current sensor.
LEM’s HSU integrates both sensing methods into one unit for installation within the Battery Disconnect Unit (BDU). Signals from the shunt and the Hall effect sensor are routed separately to the BMS, which manages the data for system operation and safety.
At the BDU level, the HSU offers:
- A reduced footprint, weight, and bill of materials (BOM)
- A simplified integration for faster time to market
- Upgrade flexibility without changes to the mechanical layout
At the BMS level, it helps developers meet Automotive Safety Integrity Level D (ASIL D) compliance.
The unit features a low-resistance shunt (25 µΩ) and galvanically isolated Hall effect sensor. It maintains 2% accuracy at 500 A and 5% at 2000 A. Communication lines are separated by function, one for the shunt and another (analog or digital) for the Hall sensor. The device also includes an NTC signal for temperature compensation.
Current measurement is rated up to ±2000 A (10-second pulse) with an operating temperature range of –40° to +125° C. The HSU fits into a standard shunt footprint and is designed for ease of installation. Two initial versions are offered: HSU00, for 84 × 36 × 3 mm busbars, and HSU01 (available in June) for 84 × 20 × 3 mm configurations.
LEM expects to expand the HSU product family to include additional hybrid configurations, such as shunt plus coreless Hall-effect combinations, with the aim of reducing size and cost while improving performance. Samples are currently available.
Filed Under: Technology News