Laboratory Training - Fuel Cell Stack

Technical Workshop:

Laboratory Training - Fuel Cell Stack

Target Group: Researchers, engineers, and technical professionals

Group Size: min. 4, max. 8 (if more people are interested, we might offer a second training)

Trainer: Leander Kucklick

Scope: 2 h

Preliminary Outline:

Theoretical Foundations:

• Fundamentals and Advantages of Fuel Cells: Introduction to fuel cells as electrochemical energy converters that directly transform chemical into electrical energy, with key benefits including high efficiency, low emissions (only water when using hydrogen), low noise, and modular scalability.
• Working Principle and Structure of PEM Fuel Cells: Detailed explanation of Proton Exchange Membrane Fuel Cells (PEMFC), including the electrochemical reactions at the anode and cathode, and the function of components like the membrane, catalyst layers, gas diffusion layers, and bipolar plates.
• System Integration and Operating Conditions: Overview of how fuel cells are integrated into complete systems, covering gas processing, power conversion, and thermal management; focus on water and heat management, especially for PEMFCs.
• Electrochemical and Thermodynamic Principles: Discussion of reaction enthalpy, Gibbs free energy, reversible cell voltage, and the Nernst equation; introduces the theoretical limits of fuel cell efficiency and the influence of temperature and pressure.
• Performance Characteristics and Loss Mechanisms: Analysis of polarization losses (activation, ohmic, concentration), current-voltage curves, and efficiency metrics such as voltage efficiency, fuel utilization, and overall power efficiency.

Practical Part:

• Test Setup and Operation: The practical experiment uses an 8-cell PEM fuel cell stack operated with hydrogen on the anode side and ambient air on the cathode side. Gases can be humidified through heated water baths or fed dry via a bypass. Parameters such as temperature, humidity, and flow rate are monitored and adjusted using LabView.
• Startup and Parameter Control: Before beginning the experiment, all components (heaters, humidifiers, sensors, heating bath) are activated. The humidifier and gas lines are heated to prevent condensation. The flow rates are regulated to maintain defined stoichiometries (e.g., λ_H₂ = 1.25 and λ_O₂ = 2.25).
• Experimental Tasks: Participants carry out several experiments, including comparing two defined operating points (10 A and 20 A), recording current-voltage characteristics (U-I curves) at two different stack temperatures (50°C and 60°C), and calculating the hydrogen flow and overall fuel cell efficiency using provided formulas.
• Data Collection and Evaluation: U-I characteristics and power output are recorded at multiple operating points. Students are required to evaluate how temperature affects cell performance and efficiency, and graph the resulting curves. Efficiency is analyzed using both electrical output and fuel input based on lower heating value.