Automotive Battery Management System (BMS)

An automotive battery management system (BMS) is the “brain” of a an electric vehicle battery pack, and its performance greatly affects driving range and battery life of an electric vehicle. Renesas products are ideal for accurate and safe BMS applications.

This reference design operates as an example of a complete automotive battery management system for up to 70 series connected Li-ion cells. The RH850 microcontroller (MCU) communicates with the ISL78714 multi-cell Li-ion battery manager devices to monitor cell voltage, pack temperature and current, record significant fault detection, and control cell balance. The ISL78714 contains daisy chain hardware to provide robust, isolated communication between batteries. The RH850 can interface to multiple CAN, LIN, UART, and RS-485 buses and control multiple PWM outputs. The reference design is based of of the ISL78714BMS5XBEKIT1Z automotive-grade multi-cell Li-ion battery manager reference design kit.

ISL78714BMS5XB-EVKIT1Z Reference Design Board

Reference Design Board

System Benefits

  • Best BMS accuracy and long-term drift (LTD), which extend driving range and battery life performance, with superior accuracy of 2mV and 6 sigma LTD
  • Lowest BOM cost and best FuSa/EMI/EMC/hot-plug solution, which alleviates R&D effort and is easy to use with Renesas' RH850 MCU Family (with dedicated drivers and software for BMS)
  • MCU line-up supporting functional safety features up to ASIL-D as well as required security features
  • Intelligent power device (IPD) for external load control
  • Full system deliverables committed to automotive quality and support, which are optimized to be used in high voltage battery management applications
System Block Diagram

Automotive Battery Management System