應用於燃料電池內水熱監測之微型軟性感測器

Apply micro flexible sensors in fuel cell for water and thermal monitoring

李重儒(Chung-Ju Lee)

指導教授 ： 李其源

元智大學/工程學院/機械工程學系/碩士(2012年)

https://doi.org/10.6838/YZU.2012.00274

摘要

燃料電池的操作溫度以及內部積水情況對於電池性能影響甚鉅，而環境狀態的不均勻性仍然存在於電池內部各個區域。過去以水熱條件的研究多以釐米尺度、破壞性量測、模擬方式得知，無法確實量測到內部資訊。
有鑑於此，本研究以微機電系統(Micro-Electro-Mechanical Systems, MEMS)開發軟性微型溫度、壓力及流量感測器。研究架構分為以下兩大類別：1. 微型感測器製作：利用PI薄膜製作出軟性微感測器。2. 燃料電池內即時監測：將微感測器嵌入燃料電池內，時間以秒為單位持續觀測電池內部溫度、壓力與流量資訊與現象分析。
燃料電池內部變化在溫度方面，下游溫度會較上游與中游溫度偏高，原因在於上、中游生成熱可被入口充足氣體帶走，而下游反應劇烈，造成下游處溫度較高；壓力方面，長時間觀察發現內部壓力於某些時刻短暫升高又回復，推測為流道積水現象生成與排除；流量方面，流量控制器供給之流量較上游與下游微感測器高，差值也與氣體洩漏值相符，流量於操作開始後數十秒達到穩定。

關鍵字

微機電系統 ； 微型感測器 ； 燃料電池

並列摘要

The temperature and flooding phenomenon during operation can strongly influence fuel cell performance. Non-uniform conditions exist in each segment of fuel cell. Previous studies have investigated these conditions on the mm scale using destructive methods or simulation, but none has been able to obtain exact data from within the cell.
This research applies micro-electro-mechanical systems (MEMS) to develop a micro flexible temperature, pressure and flow sensor. It is composed of main two parts: 1. Fabrication of micro flexible sensors on PI film by MEMS; 2. Embedding micro sensors into a PEMFC, and monitoring local temperature/ pressure/ flow rate of PEMFC and cell performance.
Internal temperature data demonstrate that the downstream exceeds upstream and midstream, because the generated heat is carried by gas from the inlet and downstream, where it undergoes a severe reaction. Monitoring the inner pressure for a long period revealed that the accumulation and elimination of water in flow field may be responsible for increased pressure and the recovery. The flow rate that is supplied by the flow controller in the testing system exceeds those measured by the upstream and downstream sensors. This deviation is consistent wit the results of a fuel cell leak test. The flow rate becomes stable after dozens of seconds from the start of operation.

並列關鍵字

MEMS ； micro flexible sensors ； fuel cell.

參考文獻

[3] X. Wang, B, Zhou, “ Liquid water flooding process in proton exchange membrane fuel cell cathode with straight parallel channels and porous layer, ” Journal of Power Sources 196, pp. 1776-1794 (2011).

[4] A. Casalegno, L. Colombo, S. Galbiati, R. Marchesi, “ Quantitative characterization of water transport and flooding in the diffusion layers of polymer electrolyte fuel cells, ” Journal of Power Sources 195, pp. 4143-4148 (2010).

[5] P. K. Das, X. Li, Z. S. Liu, “ Analysis of liquid water transport in cathode catalyst layer of PEM fuel cells, ” International Journal of Hydrogen Energy 35, pp. 2403-2416 (2010).

[6] K. Nishida, T. Murakami, S. Tsushima, S. Hirai, “ Measurement of liquid water content in cathode gas diffusion electrode of polymer electrolyte fuel cell, ” Journal of Power Sources 195, pp. 3365-3373 (2010).

[7] C. Chen, T. F. Fuller, “ The effect of humidity on the degradation of Nafion® membrane, ” Polymer Degradation and Stability 94, pp. 1436-1447 (2009).