可撓式微型感測器應用於微型燃料電池內部溫、濕度之即時監控

In situ temperature and humidity diagnosis within micro fuel cell using flexible micro sensors

吳冠緯(Guan-Wei Wu)

指導教授 ： 李其源

元智大學/工程學院/機械工程學系/碩士(2007年)

https://doi.org/10.6838/YZU.2007.00221

摘要

在燃料電池中，膜電極組的溫度與濕度之分佈對其性能的影響具有關鍵性因素，一般傳統的溫度與濕度感測器由於體積較大，只能藉由在燃料電池外部之雙極板與燃料氣瓶進出口，以量測燃料電池的操作溫度與濕度，而此量測結果並非實際膜電極組之溫、濕度狀態。

本文之目的是利用微機電系統技術製作出具有可撓性之微型感測器，以量測微型燃料電池內部的膜電極組之溫、濕度。研究架構主要分成三大部分：1. 微流道雙極板之製作：以不鏽鋼為基材，利用濕蝕刻的方式蝕刻出微流道。2. 可撓式微型感測器之製作：利用化學蒸氣沈積的方式沈積上下兩層聚對二甲苯，以完全包覆微型感測器，使其具有可撓性。3. 膜電極組溫、濕度之即時監測：將製作完成之微型感測器埋置於膜電極組內並與微流道板作組裝，以即時監測在操作中的燃料電池其膜電極組之溫濕度情形與電池性能。

而所製作完成的可撓式微型溫、濕度感測器其靈敏度分別為4.81×10-3 (1/℃)與0.03 (pF/%RH)，在燃料電池的性能量測上，當膜電極組在有、無微感測器時，其電池性能分別為179 (mW/cm2) 與341 (mW/cm2)，電池性能總共降低了162 (mW/cm2)。而當操作條件在1. H2/O2氣體流量：50 (ml/min)；2. 氣體加濕：75 (%RH)；3. 電池操作溫度：50 (℃)；4. 電池電壓：0.45伏特(Volt)時，燃料電池所產生的最大功率密度為358 (mW/cm2)。

關鍵字

燃料電池 ； 膜電極組 ； 微機電系統 ； 可撓性 ； 微型感測器

並列摘要

The purpose of this study is to fabricate flexible micro sensors for measuring the temperature and humidity distributions of micro fuel cell within MEA by Micro-Electro-Mechanical-Systems (MEMS) technology.

This research is mainly divided into three parts: 1. To fabricate the bipolar plates with micro flow channel: The stainless steel substrate is etched to form the micro flow channel by wet etching method. 2. To fabricate the flexible micro sensor: The two poly-para-xylylene (parylene) thin films are deposited as the top and bottom layers for cover over the micro sensor which have flexibility by chemical vapor deposition. 3. To diagnosis the in situ temperature and humidity distribution of MEA: The flexible micro sensors are embedded to the MEA and assemblied to the micro flow channel plate for measuring the temperature and humidity within MEA and cell performance at the same time in an operating fuel cell.

The sensitivity of flexible micro temperature and humidity sensor is 4.81×10-3 (1/℃) and 0.03 (pF/%RH) respectively. In fuel cell test, the performance of MEA without and with micro sensor is 341 (mW/cm2) and 179 (mW/cm2). The performance reduced 162 (mW/cm2). At optimal operating conditions, the maximum power density of fuel cell is 358 (mW/cm2).

並列關鍵字

Fuel cell ； MEA ； MEMS ； Flexible ； Micro sensor

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