不同碳纖維結構加強燃料電池石墨雙極板之性質研究與雙極板製程中之脫模劑選用評估

本論文主要是探討質子交換膜燃料電池的組件雙極板，其添加碳纖維加強材的組份、製程及其相關性質的關係。本研究以石墨作為導電材料，以粉末狀熱固性環氧樹脂及液態狀環氧樹脂作為黏結劑，將兩者均勻混合後，再加入碳纖維為加強材，利用熱壓機熱壓加溫，製成厚度為2mm的石墨複合雙極板。本研究主要探討雙極板添加不同編織的碳纖維結構及使用不同形態環氧樹脂製成雙極板，並量測不同結構對其機械、導電率、氣密、及熱傳導等重要性質的影響；最後將此石墨複合雙極板組裝成單電池，進行IV及IP曲線之測量，以分析比較不同的碳纖維結構與不同形態環氧樹脂製造之雙極板拉載性能的差異。其結果顯示：粉態環氧樹脂製之複合導電板之石墨連通性較高，有較良好的導電效果；而液態環氧樹脂製之複合導電板之石墨與環氧樹脂鍵結力較強，故機械性質較佳；當複合板中加入碳纖維時，確能有效提升其機械性質及導電率。本研究實驗結果顯示: 密度為2g/cm3之粉態複合雙極板之(16,16)碳纖維結構在電壓0.369V時可得到最高功率密度為830.394 mW/cm2。研究另一部份為探討使用模具熱壓壓製雙極板時的脫模問題。為了使雙極板能順利從模具中取出又需確保流道的完整性，研究採用不同性質的脫模劑與脫模方式。結果顯示：採用鐵氟龍膜因模壓時，其膜會產生皺摺造成雙極板上有凹痕的產生，而影響雙極板氣密的性能；使用矽油時則因模壓時所施加的力量與流道側壁產生剪應力，使附著在模具上矽油被擠壓而被分散，造成無法順利的脫膜；硬脂酸鋅可當作內、外脫模劑使用，以內脫模劑使用時，因有助於環氧樹脂的流動，導致雙極板黏附在模具上，若作為外脫模劑使用，可以順利的脫模且成型有良好完整性。

關鍵字

石墨雙極板；脫模劑；碳纖維；環氧樹脂；燃料電池

並列摘要

This thesis is to explore several properties of PEMFC bipolar plate which were made of different carbon fiber structures with different states of epoxy, and to discuss several release agents for the hot-press molding process. In this research, the 2mm-thick bipolar plates were made of the mixture of liquid or solid powdery epoxy and graphite with several kinds of carbon fiber structures by hot-press molding process. The main issue of this study is on the influence of the structure type of carbon-fiber (different three-dimensional structures of woven carbon fiber sheet) and the state of epoxy on mechanical properties, electrical conductivity, and thermal conduction of the composite plate. And finally, the single fuel cell tests were completed to obtain the IV curves and IP curves of the fuel cells, which bipolar plates with mass density of 2g / cm3 were made of the mixture with the content of above composites.The experimental data reveal that electrical conductivity of the specimens made of powder epoxy is better than the one made of liquid epoxy. However the mechanical properties of the specimens made of liquid epoxy is better than the one made of powder epoxy. It reveals that specimens made of powder epoxy have much more closed-circuit, and the specimens made of liquid epoxy have higher bonding force. It can outstanding improve the mechanical properties and electrical conductivity of a bipolar plate by addition of carbon fiber structures.The results reveal that the fuel cell with bipolar plates reinforced by carbon fiber structure and powder epoxy has the highest power density of 830.394 mW/cm2 occurs at 0.369V. This study also used several release agents or membrane and release methods to make bipolar plates remove smoothly from the hot pressing mold. The result reveals that a few folds emerged when Teflon membrane was used as release membrane. This resulted in gas leaking. There was shear stress between silicone oil and wall of mold during hot pressing when silicone oil was used to be release agent, silicone oil was dispersed and graphite adhered to the mold wall. If Zinc stearate was utilied to be the external mold release agent, the bipolar plate can remove smoothly from the hot pressing mold.

並列關鍵字

Graphite bipolar plates ； Release agent ； Carbon fiber ； Epoxy ； Fuel cell

參考文獻

[14]周淑金，2002，”PEMFC燃料電池雙極板之發展及方向”，質子交換膜燃料電池專刊，49卷，3期。

[1]Ki Hyun Kim, et al., 2013,“Development of carbon fabric/graphite hybrid bipolar plate for PEMFC”, Composite Structures, Vol.98, pp.103-110.

[2]Jun Woo Lim, et al., 2014,“Conductive particles embedded carbon composite bipolar plates for proton exchange membrane fuel cells”, Composite Structures , Vol.108, pp.757-766.

[3]Minkook Kim, et al.,2015,“Surface modification of carbon fiber phenolic bipolar plate for the HT-PEMFC with nano-carbon black and carbon felts”, Composite Structures, Vol.119, pp.630-637.

[4]Minkook Kim, et al., 2012,“Bipolar plates made of plain weave carbon/epoxy composite for proton exchange membrane fuel cell”, International Journal of Hydrogen Energy, Vol.37, pp.4300-4308.

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不同碳纖維結構加強燃料電池石墨雙極板之性質研究與雙極板製程中之脫模劑選用評估

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