8.9 An On-Cell Monitoring and Balancing System with Near-Field Communications for EV Batteries

A battery cell monitoring system for automotive and grid energy storage applications is presented. As part of a battery management system (BMS) it enhances pack performance and reliability, and safety with timely identification of faults and performance loss. It comprises two subsystem types: (i) the system hub (SH) mounted at the module or pack level, and (ii) the cell monitor (CM) mounted one per cell which reports on its respective cell and performs charge balancing. Figure 8.9.1 details how the BMS is arranged and how the SH interfaces with a third-party host processor. Figure 8.9.2 shows a real-life implementation of the system. Up to 216 CMs are supported per SH. Three essential features of the system are presented: I. CM chip architecture; II. Network robustness: the serial contactless communication and network formation; and III. Cell reusability: the per-cell distributed processing and data storage.