A bidirectional equalization method of Lithium ion Batteries

Because of their advantages of no memory effect, relatively long lifetime, and high energy density, lithium ion batteries have now become one of the most popular rechargeable batteries. However, there are some limitations on the usage of these batteries such as low temperature tolerance, potential danger of overcharge, and potential damage of over discharge. Therefore, a battery management system (BMS) is required to guarantee the maximum performance and safety. A traditional BMS for lithium ion batteries can take measurements and turn the system on and off based on the measurement results. This type of BMS also always has an equalization method for balancing the voltages of the series connected cells. However, these standard functions are not sufficient for modern lithium ion battery applications. In this paper, A bidirectional equalization method of Lithium ion Batteries is proposed, which can rapidly measure and balance the voltage of batteries.