Electrical measurement technology specialist LEM has launched a new current sensing unit for battery management in EVs.
LEM has put together shunt and open-loop Hall effect technologies in a single part, called Hybrid Supervising Unit (HSU), to meet the challenges of small footprint, low cost and high safety level requirements in EV battery management systems.
For higher safety levels, system engineers typically use two separate devices, a shunt to measure 2,000 A and a current sensor fully isolated for measurements to 2,000 A. LEM has combined the capabilities and performance of both technologies into a single unit, integrating it into the BDU. The signals from the shunt and the current sensor are then collected by the BMS.
At BDU level, the HSU allows minimal footprint, weight and cost, minimized integration effort for faster time to market and easy system upgrade, without impacting the mechanical layout while improving safety.
At the BMS level, the HSU is designed to enable system developers to easily reach the ASIL-D safety level required for EVs.
The shunt’s resistance is low at 25 µΩ, and the Hall part is galvanically isolated, demonstrating accuracy of 2% at 500 A and 5% at 2,000 A. Signal communication lines are separated—shunt signal and analogue or digital bus for the Hall part—and there is a negative temperature compensation signal for shunt temperature compensation.
The current measuring range is up to ±2,000 A at 10 s for both parts, and the operating temperature range is -40° C to 125° C.
The HSU is a plug-and-play unit, allowing easy mounting. LEM is initially offering the HSU00 part and the HSU01 will follow this month. The two are suitable for the two most common BDU busbar sizes: 84 x 36 x 3mm (HSU00) and 84 x 20 x 3mm (HSU01).
LEM plans to expand its HSU lineup by introducing new technologies, for example combining a shunt with a coreless Hall-effect part. The goal is to continue to shrink the devices’ size and cost while improving their performance.
“The HSU represents a significant innovation in sensor technology, being the first to combine shunt and Hall effect sensing into a single component. This integration simplifies system architecture, enhances safety and allows for seamless upgrades without altering the mechanical layout. Additionally, it reduces the total bill of materials and minimizes cycle time at the customer’s end,” said Jérémie Piro, Product Manager Battery Management Systems and Battery Storage at LEM.
Source: LEM
