No abstract

Polymer electrolyte fuel cell (PEFC) systems are expected for the use in mobile and stationary application. In this study, performance of 1 kW PEFC stack was evaluated for the reliability improvement. From the experimental results, the stack efficiency was 43.8% at 960.6 W (Higher Heating Value, HHV). From the measurement of single cell voltages, it was clarified that the difference existed on each cell at high load. It was considered that the ununiformity of MEAs and imprecise assembly of the stack affected mightily the cell voltage distribution. The improvement of the cell performance from the minimum voltage to the average level was supposed to be 10%.

Polymer electrolyte fuel cell (PEFC) has advantages because of less environmental impact and high system efficiency. It is expected to use many applications such as fuel cell vehicles, residential fuel cell systems. However, there are many technical problems to overcome for the practical use of fuel cells. In particular, it is important to improve the system reliability and the stack failure diagnosis. In this study, PEFC stack performances and effects of cooling failure were investigated. From the result, voltage deviations were calculated in consideration of the Nernst loss caused by the hydrogen partial pressure loss. From the results of a cooling failure test, the plugged cell temperature increased by 8.65 åC at 33 A. The voltage of plugged cell increased on the cooling failure test, though the stack voltage dropped.

Polymcr clcctro 且 yte fuel cell ( PEFC ) has advantages because c｝f 且 ess environmental impact and high systcm ef 置ciency ． 夏 t is expeot ¢ d to use many apPlications such as fUcl ccll veli ｛ c ］ es ， res 王 dential fuel cell systems ． Howcver ， thcre are many technical problemg． to overcomc fbr the practical use of 釦 ei ce ］ ls ． ． In partjcu ］ ar ， it is important to improve the systcm reliabil ｛ ty and the stack fai ］ ure diagnosis ． In this study ， PEFC stack pe曲 mances and e 撫 ts of じooling failure wcre investigated ． From the result ， voltagc d副 ations were calculated in consideration of the Ncrng ． t log ． s caused by the hydrogen partial pressurc loss ， From thc rcsults of acooling failure test ， the pluggcd cell ternperature increased by 8． 65 ℃ at 33 A 、 The voitage ofp 】 ugged cel ］ jncreased on the cooling failure test ， though the stack voltage dr｛｝ PPed ．