Research on mechanical behaviors and adhesion of fuel cells

Abstract

For the last few decades, the importance of eco-friendly energy and sustainability have grown continuously. Among many related technologies, fuel cell technology is one of the most researched topic which already has many applications, such as fuel cell electric vehicles or stationary power supply. In fuel cell technology, proton exchange membrane fuel cell (PEMFC) and solid oxide fuel cell (SOFC) are most popular fuel cell types. For PEMFC, mechanical behaviors and adhesion of membrane electrode assembly (MEA) and gas diffusion layer (GDL) will be discussed in order to solve the mechanical reliability issues. The mechanical properties of MEA electrode was quantitatively measured by adopting innovative “ice-assisted separation method”. Until now, mechanical properties of MEA electrode have never been experimentally measured due to difficulty of handling the electrode during tensile test and separating the electrode from the support layer without significant damage. By using innovative and quantitative method, elastic modulus of PEMFC electrode was measured for the first time. This technique was also used to predict the mechanical life cycle of the electrode. By further studying this technique, it will be possible to predict the life cycle of the MEA much faster than conventional method. Also, the delamination issue is very critical problem for long-term durability of MEA. Therefore, quantitative and accurate adhesion measurement method for MEA was developed in this thesis. In this topic, the optimum condition for various hot press parameters were also discovered. Also, guideline for choosing the most optimum parameters is suggested. This adhesion measurement method was also applied to GDL, which is another important component for PEMFC. In the second part of this thesis, interfaces between electrode and electrolyte of SOFC were observed. This interface contains triple phase boundary (TPB), which is very crucial to the SOFC performance. However, the actual undamaged TPBs have not been uncovered until now. The TPB morphology evolution due to different annealing and sintering temperatures has been analyzed by various methods.