The Evolution Of Electric Vehicle Battery Management Systems: From Passive To Active Cell Balancing

As electric vehicle (EV) manufacturers work to make batteries more affordable and easier to produce in mass quantities, we’re seeing changes in battery chemistry. For example, the industry is shifting from traditional lithium ion batteries with cobalt to lithium iron phosphate (LFP) batteries. Rare-earth metals like cobalt are in short supply, and materials like LFP are a more plentiful, sustainable, and efficient alternative.

At Knowles Precision Devices, we’re interested in trends in battery chemistry because they’re inspiring battery management system (BMS) advancements. A BMS is responsible for monitoring and controlling battery stack performance by managing temperature, performing state-of-charge (SoC) estimations, and carrying out cell balancing.

While passive cell balancing was once the more common technique, some EV manufacturers are shifting to active cell balancing in response to BMS advancements. This change impacts component selection at all levels, including capacitor selection. BMS with active cell balancing technology calls for specially designed, high-quality capacitors.