ABSTRACT This study presents a time‐resolved numerical investigation of membrane hydration dynamics in proton exchange membrane fuel cells (PEMFCs) operating under realistic automotive driving cycles and variable ambient conditions. A physics‐based model was developed to capture the coupled electrochemical, thermal, and hydration phenomena across a full transient load profile. Weather‐dependent boundary conditions, recorded during a 120‐min real trip, enabled the assessment of membrane response over a wide temperature range (22–50°C) and relative‐humidity span (20%–85% RH). Results indicate that under humid conditions (RH > 70%), the membrane remains well hydrated (λ ≈ 10; σ ≈ 0.085 S cm − 1 ), whereas dry environments (RH < 30%) induce dehydration (λ < 6) with conductivity falling to ≈0.045 S cm − 1 . To sustain adequate ionic transport in hot, dry phases, the water‐injection demand increased nearly 10‐fold, reaching 0.01 kg s − 1 . Model predictions showed good agreement with Toyota Mirai operating data and Department of Energy PEMFC performance targets, confirming the framework's fidelity. These findings underscore the importance of climate‐adaptive humidification control for maintaining PEMFC performance and durability in fuel‐cell vehicles exposed to variable environmental conditions.
Bouziane et al. (Sun,) studied this question.