Active Battery Management System for Home Battery Energy Storage

The home battery energy storage systems (ESSs) are expanding worldwide together with the renewable energy sources (especially solar power plants). As the energy sourced by the different power sources (sun, wind, electrical grid) has to be stored inside the ESS the electrochemical cells (batteries) are usually used. The key parameters of the individual cells (internal resistance, capacity etc.) may differ significantly due to the manufacturing tolerances and also the operating conditions (temperature, load current) affect the current state of the individual cells. Therefore, the state of charge and open cell voltage are unbalanced. In order to prolong the battery life time, ensure the device safety and monitor the voltage and energy levels of each cell the active battery monitoring system (BMS) is a necessity. This paper describes mainly the hardware architecture of the complex BMS allowing the user to monitor the exact values of the actual cell voltage levels, temperatures in the battery modules and many status information concerning the BMS and cell health status.