Proposal of Mission Profile-Based Degradation Model for Electric Double-Layer Capacitors

This paper proposes a mission-profile-based degradation model for electric double-layer capacitors (EDLCs) under variable electrical stress. The approach extends an exponential deterioration model for capacitance and equivalent series resistance (ESR) to repeated operating profiles by representing voltage- and temperature-dependent degradation through an equivalent scaled operating time. The formulation establishes conditions under which a Miner-type cumulative time-scaling rule is consistent with exponential degradation models with time-dependent degradation rates. The model is evaluated using endurance measurements of commercially available 50 F EDLCs aged at 65 ∘C under constant DC voltages between 1.5 V and 2.7 V and under a stepped profile alternating between 1.8 V and 2.7 V. Capacitance measurements show clear voltage-dependent degradation and provide the primary validation of the proposed scaling approach. The model reproduces the main capacitance-degradation trends under constant and time-varying voltage stress. The results provide initial support for mission-profile-based degradation assessment of EDLCs; further validation under broader stress conditions and load profiles is required.