Overview of supercapacitor cell voltage balancing methods for an electric vehicle

Supercapacitors (SCs), also known as electric double-layer capacitors or ultracapacitors, are energy storage devices that store electrical energy without chemical reactions. Supercapacitor energy storage system are affected by many factors, the most important one is the cells unbalancing. Without the balancing system, the individual cell voltages will differ over time, supercapacitor pack capacity will decrease quickly. That will result in the failure of the total energy storage system. Thus cell balancing acts an important role on the battery life preserving. This paper presents an evaluation of relevant existing cell voltage balancing solutions from literature with analytical and simulation analysis, the comparison carried out according to circuit design, balancing simulation, application, balancing speed, complexity...etc.