Rethinking SOH: Understanding Battery Health in the Real World

State of Health (SOH) is widely used as a measure of battery health, but a single SOH percentage can often hide what is actually happening inside the battery. This becomes particularly important in understanding the difference between Cell SOH and Pack SOH—where the weakest cells, cell-to-cell variations, imbalance and pack-level operating conditions can make the actual health and usable performance of the pack very different from the health indicated at an individual cell level.

This webinar will explore the gap between theoretical SOH and on-ground SOH—the difference between the health a battery is expected to have based on rated capacity, models, test conditions, and calculated degradation, and the health it can actually demonstrate under real-world conditions. We will examine how cell imbalance can reduce usable energy at the pack level, where the weakest cell reaching its voltage limit can restrict the pack before the remaining cells have fully utilised their available energy.

We will also examine internal resistance growth and its impact on both energy and power capability. Increased resistance can cause greater voltage drop under load, reduce the practically usable capacity/energy, increase heat generation, and limit the power the battery can deliver or accept. By connecting cell behaviour, pack dynamics, operating conditions, and real-world data, the session will challenge the idea that SOH is simply a percentage—and explore how to move toward more meaningful, actionable Battery Health Intelligence.