Battery Degradation and Performance

Dynamic Cycling versus Constant-current Cycling EV lifetime is often assessed with static constant-power aging tests, while real driving is dynamic with long rests. This work shows such tests can overstate degradation because a large part of the measured “agingˮ is reversible.

If this reversible part isnʼt separated out, aging tests and models will underestimate real-world lifetime and mislead design and warranty decisions. Four 18650 NCA/Si-Gr cases (static vs. dynamic urban/highway; same average power; 60% DoD) show faster apparent capacity loss and resistance rise under static cycling, attributed to reversible anode lithiation/electrolyte inhomogeneity. After 15 months low-SOC rest, cells recover 52% of the capacity loss and 66% of the resistance rise, informing accelerated-test designs that incorporate rest and separate apparent from true aging.

Static cycling can overstate degradation, since long low-SOC rest reverses a large fraction of observed capacity/resistance changes.

Source: Schreiber et al., Journal of Energy Storage, 2025.

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