표제지
국문 초록
목차
1. 서론 12
2. 이론 16
2.1. 기상에서의 활성화 과전압 16
2.2. 오믹 과전압 16
2.3. 기상에서의 농도 과전압 17
2.4. 액상 물에 의한 과전압 19
3. 방법 20
3.1. 방법론 20
3.2. 실험 구성 23
3.3. 구조해석 32
4. 결과 및 고찰 35
4.1. 셀 전압 35
4.2. 기상에서의 활성화 과전압 39
4.3. 오믹 과전압 47
4.4. 기상에서의 농도 과전압 54
4.5. 액상 물에 의한 과전압 60
4.6. 전체 셀 과전압 65
5. 결론 70
References 72
Abstract 76
Table 1. Mechanical properties of cell components 25
Table 2. Operating conditions for electrochemical experiments 25
Table 3. Rib/Channel position area. 28
Table 4. Measuring device manufacturer and specifications 31
Table 5. Element value of EIS fitting data 43
Fig. 1. Schematic of overpotential decomposition. 22
Fig. 2. Single-cell components for experiments. (a) End Plate, (b) Current Collect Plate, (c) Bipolar Plate, (d) Gasket, (e) Membrane Electrode Assembly, (f) Gas Diffusion Layer 26
Fig. 3. (a) Flow path type of bipolar plate. (b) Flow path combinations. 27
Fig. 4. Rib/Channel position, Black: Rib to Rib, Gray: Rib to Channel, White: Channel to Channel. 28
Fig. 5. Hydrogen and air inlet direction 29
Fig. 6. Piping & Instrument diagram of polymer electrolyte fuel cell test station 30
Fig. 7. Single-cell components for structure simulation 33
Fig. 8. Boundary conditions for structure simulation. 33
Fig. 9. Dependency of the average pressure on the number of element nodes 34
Fig. 10. Finite element model of single cell 34
Fig. 11. Cell voltage i-V curve. Condition I: Stoic. 2/2.5, RH 100/40 (H₂/Air). 36
Fig. 12. Cell voltage i-V curve. Condition II: Stoic. 1/1.5, RH 100/40 (H₂/Air). 37
Fig. 13. Cell voltage i-V curve. Condition III: Stoic. 1/1.5, RH 100/60 (H₂/Air). 38
Fig. 14. The activation resistance obtained by differentiating the activation overpotential with respect to current at... 41
Fig. 15. The activation resistance obtained by sum of anode and cathode faradaic resistance at 0.8V. The faradaic... 42
Fig. 16. Equivalent circuit model. Ohmic resistance(RΩ), Anode and Cathode Faradaic resistance (Rƒ.A,Rƒ.C), Anode and Cathode double-layer capacitance (Cdl,A, Cdl,C), Warburg coefficient(Wₛ)[이미지참조] 43
Fig. 17. Activation overpotential ignoring liquid water. Condition I: Stoic. 2/2.5, RH 100/40 (H₂/Air). 44
Fig. 18. Activation overpotential ignoring liquid water. Condition II: Stoic. 1/1.5, RH 100/40 (H₂/Air). 45
Fig. 19. Activation overpotential ignoring liquid water. Condition III: Stoic. 1/1.5, RH 100/60 (H₂/Air). 46
Fig. 20. Average contact pressure to the Ohmic resistance. Average contact pressure obtained at the interface the... 49
Fig. 21. Pressure distribution obtained at the interface between the MEA and GDL through structure simulations. Pressure... 50
Fig. 22. Ohmic overpotential. Condition I: Stoic. 2/2.5, RH 100/40 (H₂/Air). 51
Fig. 23. Ohmic overpotential. Condition II: Stoic. 1/1.5, RH 100/40 (H₂/Air). 52
Fig. 24. Ohmic overpotential. Condition III: Stoic. 1/1.5, RH 100/60 (H₂/Air). 53
Fig. 25. Oxygen transport resistance calculated from the liming current density at 3%, 6%, 9% oxygen molar fractions.... 55
Fig. 26. Oxygen transport resistance calculated from the liming current density at 3%, 6%, 9% oxygen molar fractions.... 55
Fig. 27. Oxygen transport resistance calculated from the liming current density at 3%, 6%, 9% oxygen molar fractions.... 56
Fig. 28. Concentration overpotential ignoring liquid water. Condition I: Stoic. 2/2.5, RH 100/40 (H₂/Air). 57
Fig. 29. Concentration overpotential ignoring liquid water. Condition II: Stoic. 1/1.5, RH 100/40 (H₂/Air). 58
Fig. 30. Concentration overpotential ignoring liquid water. Condition III: Stoic. 1/1.5, RH 100/60 (H₂/Air). 59
Fig. 31. Liquid water overpotential. Condition I: Stoic. 2/2.5, RH 100/40 (H₂/Air). 62
Fig. 32. Liquid water overpotential. Condition II: Stoic. 1/1.5, RH 100/40 (H₂/Air). 63
Fig. 33. Liquid water overpotential. Condition III: Stoic. 1/1.5, RH 100/60 (H₂/Air). 64
Fig. 34. Cell voltage and overpotential measured at 1.4 A cm⁻², separated into four components: activation overpotential... 67
Fig. 35. Cell voltage and overpotential measured at 1.4 A cm⁻², separated into four components: activation overpotential... 68
Fig. 36. Cell voltage and overpotential measured at 1.4 A cm⁻², separated into four components: activation overpotential... 69