本研究將碎形理論與熱傳導模型結合並預測燃料電池中的氣體擴散層之熱傳導係數，以實驗值與預測值相互驗證，探討氣體擴散層於不同施加壓力和有無PTFE、MPL的情況下，對熱傳導係數的影響。以碎形熱傳導模型預測Toray公司的TGP-H-090、TGP-H-090-20碳紙和SIGRACET? 35BC氣體擴散層之預測值分別為1.77 Wm^(-1) K^(-1)、1.54~2.4 Wm^(-1) K^(-1)和0.62 Wm^(-1) K^(-1)，反映樣貌和內部構造改變造成的物理性質差異，近似真實物理現象。本研究根據ASTM D5470標準自製之熱傳導量測儀器進行實驗，操作溫度設定為50℃，施加壓力0.72~1.39 MPa，在量測樣本中，Toray公司的TGP-H-090的熱傳導係數為1.02~1.31 Wm^(-1) K^(-1)，TGP-H-090-20則是0.86~1.08 Wm^(-1) K^(-1)，隨著施加壓力增加，熱傳導係數提高，TGP-H-090-20塗佈自製MPL，在施加壓力0.72~1.16 MPa下為0.67~0.81 Wm^(-1) K^(-1)，而SIGRACET? 35BC在壓力0.94 MPa則是0.32 Wm^(-1) K^(-1)，實驗數據雖低於大部分學者之實驗值，但趨勢上符合加入PTFE和MPL會使得熱傳導係數下降。The fractal theory is combined with thermal conductivity model to predict the effective thermal conductivity, keff, of the gas diffusion layer (GDL) of proton exchange membrane fuel cell. The predicted values are compared with experimental results. In addition, effects of compression, PTFE loading and the addition of microporous layer (MPL) on the effective thermal conductivity are also investigated. Using the fractal thermal conductivity model, keff is predicted as1.77 Wm^(-1) K^(-1),1.54 ~ 2.4 Wm^(-1) K^(-1) and 0.62 Wm^(-1) K^(-1) for Toray’s TGP-H-090 and TGP-H-090-20 carbon paper and SIGRACET?’s 35BC GDL, respectively. These values agree with literature values. One advantage of the present model is the ability to reflect the change in keff caused by surface and internal structure differences.Furthermore, an experimental instrument based on ASTM standard D5470 is built and used to determine the through-plane thermal conductivity of GDL. The average temperature of test specimen is 50 ℃ and the compression pressure is between 0.72 ~ 1.39 MPa. keff is in the range of 1.02~1.31 Wm^(-1) K^(-1) for TGP-H-090, and 0.86 ~ 1.08 Wm^(-1) K^(-1) for TGP-H-090-20. keff increases with compression pressure. The keff of TGP-H-090-20 containing MPL is 0.67~0.81 Wm^(-1) K^(-1) under 0.72~1.16 MPa. The keff of 35BC is 0.32 Wm^(-1) K^(-1) under 0.94 MPa. Coating PTFE or adding MPL results in a decrease in keff.
