Evaluation of Fuel Cell Performance and Degradation

Abstract

The concepts of area specific resistance (ASR) and degradation are developed for different fuel cell operating modes. The concepts of exergetic efficiency and entropy production were applied to ASR and degradation. It is shown that exergetic efficiency is a time-dependent function useful describing the thermal efficiency of a fuel cell and the change in thermal efficiency of a degrading fuel cell. Entropy production was evaluated for the cases of constant voltage operation and constant current operation of the fuel cell for a fuel cell undergoing ohmic degradation. It was discovered that the Gaussian hypergeometric function describes the cumulative entropy and electrical work produced by fuel cells operating at constant voltage. The Gaussian hypergeometric function is found in many applications in modern physics. This paper builds from and is an extension of several papers recently published by the authors in the Journal of The Electrochemical Society (ECS), ECS Transactions, Journal of Power Sources, and the Journal of Fuel Cell Science and Technology.

Key findings

• ▸Exergetic efficiency is a time-dependent function describing thermal efficiency of fuel cells and change in thermal efficiency due to degradation.
• ▸Entropy production was evaluated for constant voltage and constant current operation of fuel cells undergoing ohmic degradation.
• ▸Gaussian hypergeometric function describes cumulative entropy and electrical work produced by fuel cells operating at constant voltage.

Keywords

Identifiers

DOI

10.1149/1.3570041

Journal

ECS Transactions

Year

2011