2013 Fiscal Year Final Research Report

Analysis of phase of water produced by cell reaction with a circumstance close to chemical equilibrium

Research Project

Project/Area Number	24656141
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Single-year Grants
Research Field	Thermal engineering
Research Institution	Kyushu University
Principal Investigator	ITO Kohei 九州大学, 工学(系)研究科(研究院), 教授 (10283491)
Project Period (FY)	2012-04-01 – 2014-03-31
Keywords	物質輸送 / 燃料電池
Research Abstract	The phase of production water in polymer electrolyte fuel cell (PEFC) is clarified based on the measurement of open circuit voltage (OCV). The measured OCV is corrected with considering short circuit current and Tafel equation, and the comparison between the OCV thus corrected and theoretical OCV determines the water phase if it is liquid or gas. The corrected OCV shows the same tendency with Nernst equation, where higher temperature and humidity decrease the OCV. Especially, the corrected OCV locates within the theoretical equilibrium voltages between gas and liquid production cases, and it approaches the theoretical one in the liquid production case with the increase of the humidity. This characteristics suggest that higher humidity promote the water production in liquid phase. These obtained results are thought to be worth for an optimization of water management required in PEFC.