BMS chip from STMicroelectronics extends EV range and safety
A battery management system (BMS) chip from STMicroelectronics delivers enhancements to extend driving range, reliability, and safety of electric vehicles (EVs), and introduces sensing accuracy and temperature monitoring.
The L9663 controller’s battery management technology increases reliability, safety, driving range, and cost-effectiveness of EVs, says the company.
It is the latest generation from ST’s BMS programme, which has already created advanced semiconductors for joint projects with major organisations developing EV batteries, including LG Chem, and the co-operation with Chinese R&D institute IMECAS and EV-battery technology company Epoch.
A typical BMS uses multiple L9963 devices to monitor groups of cells in the battery stack, managed by a host microcontroller such as ST’s SPC5 safety-critical, automotive-qualified MCUs.
The L9963 is in production now. It can monitor up to 14 stacked battery cells, measuring voltages with accuracy better than 2mV in the 1.7 to 4.7V range to maintain superior cell condition. Simultaneous digitisation of all sensed values, considered to be a first for this type of battery-management product, 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.
Meeting ASIL-D requirements in compliance with the ISO 26262 standard, the L9963 integrates a fully redundant cell-measurement path that enhances safety and provides support for a ‘limp home’ mode. There are also fault-detection and notification functions meeting automotive safety requirements.
The L9963 has a serial peripheral interface (SPI) and a 2.66Mbits per second vertical communication interface for high-speed communication between multiple L9963 ICs monitoring the entire battery stack. Using this structure, eight devices can convert and read 96 cells in less than 4ms and can work with any combination of transformer-based or capacitive isolation.
The L9963 also features a robust design that allows hot plugging without the external Zener diodes usually needed to protect the BMS because the battery cannot be powered down. The L9963 allows designers to eliminate these components and hence further reduce costs, adds ST.
