The Design of Embedded Electric Bicycle Battery Management System

The bottlenecks of lithium-ion batteries in electric bicycle industry was analyzed. The low-power battery management system with fault diagnosis, SOC and SOH estimates and complete data logging functions was designed based on BQ77PL900 and MSP430, to achieve a precise measurement of the voltage and extend high and low temperature protection. The system used ampere-hour integration method combined with temperature for SOC estimation, and used full charge and discharge combined with cycles for correct capacity. The SOC, SOH and historical information were uploaded via CAN bus. The reliability and stability of the system, the accuracy of SOC algorithm were verified via experiment.