A Smart Cell Monitoring System Based on Power Line Communication—Optimization of Instrumentation and Acquisition for Smart Battery Management

Abstract

Energy density of current generation battery packs is insufficient for next generation electric vehicles nor the electrification of the aerospace industry. Currently, approximately a third of energy density is lost due to ancillary demands (e.g., cooling and instrumentation) within a pack, relative to cell energy density. Smart cells, instrumented cells with sensors and circuitry, offer a means to monitor cell performance (e.g. temperature, voltage, current data). Uniquely here we demonstrate our 21700 cells instrumented with internal thermistor sensing arrays with custom miniature interface circuitry including data acquisition and communication components. This circuitry including a power line communication (PLC) system, enables sensor data to be collected and transmitted to a master controller without requiring additional wiring, and can achieve an excellent <0.005 % message error rate. The control and communication system includes the use of adaptive sampling algorithms (during identified periods of low demand, through temperature and current measurements) the cells transmit data at 0.2 Hz, increasing to 5 Hz (normal operation) or 10 Hz (beyond operating limits). This method was demonstrated via drive cycling and external heating to alert the master controller to abnormal operating conditions (rapidly, to avoid missing key features) while saving 65% volume of data during a 90 minute experiment.

Keywords

• Power line communication (PLC)
• cell instrumentation
• cell sensing
• temperature monitoring
• cell cycling