STMicro’s Efficient BMS For Clean And Safe EV Energy Management

  • New Battery-Management System (BMS) chip delivers extended driving range, battery life and safety of electric vehicles (EVs)
  • Robust and measures voltages with better accuracy

It is predicted that by 2030, electric vehicles (EVs) will reach equivalency in terms of cost concerning conventional combustion-engine vehicles and consequently take over their sales by 2038.

With this in mind, STMicroelectronics has launched a new battery-management technology that increases reliability, safety, driving range and cost-effectiveness of electric vehicles (EVs). This battery-management system (BMS) controller also features accurate voltage range for longer driving and battery life, along with temperature-monitoring inputs for enhanced safety.

Advanced monitoring of battery cells

ST’s L9963 controller is the latest BMS program, which has advanced semiconductors for EV batteries. The device can monitor up to 14 stacked battery cells, measuring voltages with accuracy better than 2mV in the 1.7V–4.7V range to maintain superior cell condition. Simultaneous digitisation of all acquired values eliminates cell-synchronisation delays.


The L9963 can also monitor up to seven external temperature sensors, enhancing the system’s ability to detect fluctuations and maintain stability.

ST’s BMS application uses several L9963 devices to monitor cell groups in the battery stack, managed by a host microcontroller (MCU) such as ST’s SPC5 high-performance, safety-critical automotive-qualified MCUs.

Faster communication speeds

With the help of a serial peripheral interface (SPI), the L9963 features a 2.66Mbps vertical communication interface for high-speed communication between multiple L9963 ICs for monitoring the entire battery stack. Thus, eight devices can convert and read 96 cells in less than 4ms, which allows them to work with any combination of transformer-based or capacitive isolation.

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The L9963 also features a robust design that allows hot-plugging without external Zener diodes (usually needed to protect the BMS as the battery cannot be powered down). So, now designers can eliminate these components and further reduce costs.

“We are extending our expertise in electronic technologies in every way possible to help realize cleaner mobility,” said Alberto Poma, ADG Vice President, Smart Power Solutions MACRO-Division General Manager, STMicroelectronics. “Building on over 10 years of work with key partners in EV battery-management technology, our new battery-management chip further improves every aspect of energy management in EVs, which directly enhances important end-user experiences to increase the market appeal and consumer confidence.”

Meeting ASIL-D compliance with the ISO 26262 standard, the L9963 enhances safety and provides support for a ‘limp home’ mode. Comprehensive fault-detection and notification functions meeting automotive safety requirements are also built-in.

The L9963 is in production now and ready for new designs.



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