高分子複合材料雙極板射出成形特性之初步探討

Abstract

近年綠色科技全球蓬勃發展，其中以燃料電池為熱門研究項目，目前燃料電池面臨普及化、輕薄微小化的挑戰，而燃料電池中雙極板所占的體積、重量最為龐大，其成本耗費也最嚴重。目前在雙極板成形上大部分使用熱壓成形，而熱壓成形其生產週期較長，製品尺寸精度差，導致生產成本提高，再加上目前材料普遍走向多樣化、強調各項材料連結性與功能性，熱壓成形缺少了流動性能，因此在複合材料中並不佔有優勢。 因此本實驗以成形週期短、可大量生產之射出成形方法使用在雙極板製程上，以射出的方式使材料流動進而增加材料間的連接。本研究以高粉末比例配方進行射出成形，製作雙面溝槽雙極板，並進行雙極板的各種性能量測。在射出時，由於材料內部存在兩種流體，因此內部相分離發生情形明顯，且離澆口越遠情況嚴重。由於高石墨粉以及奈米級碳黑比例，因此在強度、抗腐蝕、熱性質有明顯的改善；但奈米級碳黑的比例，則影響到整體導電性能。

In recent years, the vigorous green technology is developing in the world, and the fuel cell is the top topic to be researched. Now fuel cell is facing the challenges of popularization and miniaturization. The fuel cell of bipolar plate with huge size and weight, cost the most. At present, the majority of the bipolar plate is formed by hot-embossing, but hot-embossing’s production cycle is longer and the accuracy of product size, results in higher production cost. Otherwise, the current material toward the diversification emphasizes the material characterization and function, and hot-embossing lacks of the material flow,so it’s not an advantage. In this study, we use the method of injection molding to product the bipolar plate,and this method can increase material flow and the connection between materials.I used the high-proportion of powder to inject the double-sided bipolar plate groove, and then measured properties of bipolar plate. In the injection process, due to the presence of two types of fluid, the occurrence of internal phase separation is significantly, and become more serious farther away from the gate. In the material proportion with high ratio of graphite and nano-scale carbon black,the strength, corrosion resistance, and thermal properties are significantly improved, but the proportion of nano-scale carbon black affects the performance of the overall conductivity.