Mathematical Modelling and Cell Balancing of Lithium-ion Battery

The paper presents a range of energy storage devices, such as batteries and super/ultracapacitors, and demonstrate how they can be integrated with a voltage balancing circuit that utilizes a single inductor-capacitor energy converter. The circuit's primary function is to effectively transfer surplus energy from the upper cell to the lower cell in the chain, using a bidirectional MOSFET switch and an LC tank. This active balancing circuit is designed to provide fast balancing speed, compact size, low cost, and superior performance in terms of maximum energy recovery. The control of MOSFET switches is managed by synchronous trigger patterns with complementary pulse-width modulated signals, operating in a near-zero current system. This feature enables the maintenance of a zero-voltage gap between non-adjacent cells within a series battery or supercapacitor string during cyclic charging and discharging. Additionally, the resonant frequency of the circuit is the same as the switching frequency, which results in a lower resonant frequency.