Identifying Irreversibility and Optimization Pathways of Proton Exchange Membrane Fuel Cell System Based on Advanced Exergy Analysis

To deeply explore the energy-saving potential of a proton exchange membrane fuel cell (PEMFC) system, this study established thermodynamic models of system components based on actual system operational data. Building upon conventional exergy analysis to clarify exergy destruction, this employs advanced exergy analysis methods to deconstruct total exergy destruction into avoidable/unavoidable and endogenous/exogenous segments. This approach not only characterized the location and magnitude of the destruction, but also achieved a profound diagnosis of the roots of irreversibility and the potential for optimization. Research findings indicate that 66.55% of the total exergy destruction in the system constitutes avoidable destruction, highlighting significant energy-saving opportunities. The loss mechanisms of key components are distinct: the stack destruction is composed of both unavoidable fundamental irreversibility and avoidable polarization destruction. In contrast, air supply system exergy destruction predominantly stems from the inefficiency of components (endogenous), while the destruction in the cooling system is mainly caused by system-level integration constraints (exogenous). Consequently, this study delineates differentiated optimization pathways: for the stack, the focus should be on mitigating its avoidable polarization destruction through material and design innovations; for the air supply system, component technological upgrades are imperative to reduce its avoidable-endogenous destruction; and for the cooling system, effort must be directed toward system-level coordinated control optimization to overcome its avoidable-exogenous destruction. This research provides a theoretical foundation and decision-making support for enhancing the performance of automotive fuel cell systems.