A Study on Transfer Element in Single Switched Capacitor Battery Balancer System

Series-connected lead-acid battery is commonly used in a photovoltaic system. During charge-discharge cycle, each battery in the string would experience a voltage imbalance which leads to performance decay. Single switched capacitor battery balancer resolves this issue by transferring excessive charge from one battery to another. Therefore, the voltage imbalance will be at the acceptable limit. A transfer element is employed in this charge transfer process between batteries. In this paper, a battery balancer has been carried out by adopting balancing algorithm used in an LTC3305 chip. Simulation result shows that the use of the lead-acid battery as a transfer element is considerably more effective than the super-capacitor while speeding-up the balancing process.