Issue link: https://resources.mouser.com/i/1516769
Passive cell balancing is a simple and low-cost solution that involves a parallel current path controlled by the BMS and allows the current to bypass cells with higher SOC. This bypassing is achieved through power resistors and MOSFETs on each cell. Although it is the simplest and most cost-effective implementation of cell balancing, passive balancing has the notable shortcoming of operational inefficiency. The burning of power through resistors is wasted energy and ultimately decreases battery life and efficiency. Active cell balancing, on the other hand, involves the active transfer of energy from higher SOC cells to lower SOC ones to balance out overall SOC. This balancing is achieved through capacitors or inductors between cells, which store and transfer energy until SOC cells are equalized. While more efficient than passive balancing, active balancing is more complex and costly due to additional and higher-cost components. When choosing components to support active or passive cell balancing, your most important consideration is often power density. Ideal components are those that offer a combination of small size and high efficiency without sacrificing the ability to withstand high power. In cases like an EV design, a smaller size means reduced weight and cost and hopefully better vehicle range. Vishay offers customers components that optimally balance the tradeoffs of size, power, efficiency, and cost for both active and passive cell-balancing applications. C h a p t e r 3 | C e l l B a l a n c i n g For cell balancing, you're trying to balance each individual cell to improve the battery usage with the smallest possible component number and size and at the same time with the highest power capability, and that's a hard tradeoff for designers to navigate." Aimen Oueslati Senior Field Application Engineer, Vishay 15 8 Industry Experts Discuss Battery Management Solutions