Advanced Temperature Design for Dynamic Performance Enhancement of PEMFCs Under High Current Density (HCD)

Area of Science:

• Electrochemistry
• Materials Science
• Energy Systems

Background:

• Proton exchange membrane fuel cells (PEMFCs) are vital for clean energy, but their dynamic performance under high current density (HCD) rapid loading hinders commercialization.
• Effective management of water, gas, and heat is critical for stable PEMFC operation, especially during transient conditions.

Purpose of the Study:

• To investigate the impact of advanced in-plane temperature difference (TD) designs on PEMFC dynamic performance under HCD rapid loading.
• To optimize temperature distribution across fuel cell components to achieve balanced water-gas-heat management.
• To evaluate the effectiveness of different TD designs across a range of humidity conditions.

Main Methods:

• Development and analysis of various in-plane temperature difference (TD) designs with reconstructed cooling channels.
• Experimental investigation focusing on load initiation, transient voltage minimum (TVM), and steady-state voltage (SSV).
• Utilizing electrochemical impedance spectroscopy (EIS) and local current density monitoring to understand underlying mechanisms.

Main Results:

• The positive temperature difference (PTD) design improves upstream hydration and mitigates downstream flooding under low humidity.
• The PTD design significantly enhances transient voltage minimum (TVM) by 18.2% and steady-state voltage (SSV) by 5.67% at 35% RH.
• PTD design reduces voltage undershoot (VU) by 12.5% and increases overall electricity output by 7% at 35% RH.

Conclusions:

• Advanced TD designs, particularly PTD, effectively enhance PEMFC dynamic response and operational stability under HCD loading, especially at lower humidity.
• Optimized temperature gradients contribute to balanced water-gas-heat management, crucial for mitigating performance degradation.
• While the benefits of PTD diminish with increasing humidity, it consistently improves current density distribution uniformity.