Befeuchtungskonzepte für Brennstoffzellensysteme in mobilen Anwendungen

• Humidification concepts for fuel cell systems in mobile applications

Tinz, Sören Niklas; Pischinger, Stefan (Thesis advisor); Hoster, Harry (Thesis advisor)

Aachen : RWTH Aachen University (2022, 2023)
Dissertation / PhD Thesis

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2022

Abstract

Fuel cell systems in mobile applications can be an important building block for a sustainable mobility system of the future. In this context, membrane humidification has a significant influence on the operating behavior and performance of a fuel cell under various aspects. So far, two concepts - with internal humidification and with membrane humidifiers - are commonly used in fuel cell systems available on the market. Various alternatives are also discussed in the literature, but without comprehensive, quantitative evaluations being made.In this work, the most promising concepts - with internal humidification, membrane humidifiers, water injection as well as cathode exhaust gas recirculation - are compared as far as possible quantitatively on fuel cell system level. The comparison includes the determination of the system efficiency for a common reference system, the estimation of the construction volume, the classification of the system complexity as well as the evaluation of the system dynamics.The focus is on the comparison of the system efficiency. To calculate the maximum system efficiency in each case and to identify the corresponding operating parameters, a simulation model was set up for a representative fuel cell system of a rated power of 85 kW and coupled with a commercial optimizer. On a flexible fuel cell stack, component, subsystem and system test bench, stacks with humidified and dry cathode feed air as well as with cathode exhaust gas recirculation and several membrane humidifiers were measured. Based on the measurement results, correlations characterizing the components were obtained using Gaussian process regression and finally incorporated into the system simulation model.The results obtained in this work and the method developed and demonstrated, which can also be applied to systems with other topologies or with other components, are intended to serve as a sound basis for decisions on future fuel cell system developments. However, the final decision for a concept has to be made on a case-by-case basis according to the specific requirements and their weighting.

Institutions

• Chair of Themordynamics of Mobile Energy Conversion [412310]