Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical Modeling of Current Density and Water Behavior at a Designated Cross Section of the Gas Diffusion Layer in a Proton Exchange Membrane Fuel Cell

고분자전해질 연료전지의 동작압력에 대한 가스 확산층의 위치 별 전류밀도 및 수분거동에 대한 수치해석

  • Kang, Sin-Jo (Dept. of Automatic System, Korea Polytechnics V College) ;
  • Kim, Young-Bae (Dept. of Mechanical Engineering, Chonnam Nat'l Univ.)
  • 강신조 (한국폴리텍 V대학 자동화시스템과) ;
  • 김영배 (전남대학교 기계공학부)
  • Received : 2011.07.08
  • Accepted : 2011.10.20
  • Published : 2012.02.01
Download PDF
⟨ Previous Next ⟩

Abstract

There are many factors to consider when attempting to improve the efficiency of fuel cell operation, such as the operation temperature, humidity, stoichiometry, operation pressure, geometric features, etc. In this paper, the effects of the operation pressure were investigated to find the current density and water saturation behavior on a cross section designated by the design geometry. A two-dimensional geometric model was established with a gas channel that can provide $H_2$ to the anode and $O_2$ and water vapor to the cathode gas diffusion layer (GDL). The results from this numerical modeling revealed that higher operation pressures would produce a higher current density than lower ones, and the water saturation behavior was different at operation pressures of 2 atm and 3 atm in the cathode GDL. In particular, the water saturation ratios are higher directly below the collector than in other areas. In addition, this paper presents the dependence of the velocity behavior in the cathode on pressure changes, and the velocity fluctuations through the GDL are higher in the output area than in inlet area. This conclusion will be utilized to design more efficient fuel cell modeling of real fuel cell operation.

고분자 전해질 연료전지에서 물 관리는 연료 전지성능에 영향을 미치는 중요한 요인이다. 공급되는 수분의 양이 적을 경우 수소이온의 이동을 담당하는 전해질의 건조현상으로, 수분의 양이 과다할 경우 반응이 일어나는 촉매층과 전해질 삼상 계면에서의 홍수현상으로 성능을 감소시키거나 동작을 멈추게 하므로 이 부분에 대한 많은 연구가 진행되고 있다. 본 논문에서는 연료전지 수분에 영향을 주는 요소 중, 연료극과 공기극에 공급되는 상대습도를 100%로, 동작온도를 $80^{\circ}C$로 설정한 후, 입구 측에 압력을 변화하면서, 다중물리응용 수치해석을 포함하고 유한요소를 통하여 비선형 편미분 방정식이 결부된 상용코드를 이용하여 전체적인 전기화학반응 및 성능에 대한 해석을 수행하고 공기극 측의 가스 확산층에 각 위치별 전류밀도 분포와 수분포화의 분포, 압력차에 의한 동작물질의 속도 등을 분석하여 보았다. 본 연구를 통하여 얻어진 결과는 연료전지의 성능은 압력의 세기에 따라 달라지며 압력이 높을수록 성능과 위치별 최대 전류밀도가 높게 나타났으며, 공기극의 가스 확산층에서의 수분함량은 높은 압력에서보다 낮은 압력에서 수분함량이 많은 것으로 나타났으며 특히 전극의 바로 아래 부분에서의 수분이 더 많이 응축되어 나타났으며 공기극 가스 확산층에서의 동작물질의 속도는 동작물질의 입구방향에서 출구측으로 진행할수록 그 변동 폭이 크게 나타났다.

Keywords

References

  1. Kim, Y.B., 2011, "Study on the Effect of Humidity and Stoichiometry on the Water Saturation of PEM Fuel Cells," J Energy Research, DOI: 10.1002/er.1845.
  2. Quan, P. and Lai, M.C., 2007, "Numerical Study of Water Management in the Air Flow Channel of a PEM Fuel Cell Cathode," J of power Sources, Vol. 164, pp.222-237. https://doi.org/10.1016/j.jpowsour.2006.09.110
  3. Nguyen, T. and Knobble, M., 2003, "A Liquid Water Management Strategy for PEM Fuel Cell Stacks" J of power Sources, Vol. 114, pp. 70-79. https://doi.org/10.1016/S0378-7753(02)00591-8
  4. Hussaini, I.S. and Wang, C.Y., 2009, "Visualization and Quantification of Cathode Channel Flooding in PEM Fuel Cells," J of Power Sources, Vol. 187, pp. 44-451.
  5. He, W. and Yi, J. and Nguyen, T.V., 2000, "Two-Phase Flow Model of the Cathode of PEM Fuel Cells Using Indigitated Flow Fields," AIChE 46 A, pp. 2053-2064.
  6. Natarijan, D. and Nguyen, T.V., 2001, "A Two-Dimensional, Two-Phase, Multi-Component, Transient Model for the Cathode of a Proton Exchange Membrane Fuel Cell," J Electrochemical Soc. 148, A pp. 1324-1335.
  7. Wang, Z.H., Wang, C.Y. and Chen, K.S., 2001, "Two Phase Flow and Transport in the Air Cathode of Proton Exchange Membrane Fuel Cell," J of Power Sources, Vol. 94 pp. 40-50. https://doi.org/10.1016/S0378-7753(00)00662-5
  8. Meng, H. and Wang, C.Y., 2005, "Model of Two-Phase Flow and Flooding Dynamics in Polymer Electrolyte Fuel Cells," J Electrochemical Soc. Vol. 152. A, pp. 1733-1741
  9. Fuller, T.F. and Newmann, J., 1993, "Water and Thermal Management in Solid-Polymer-Electrolyte Fuel Cells," J Electrochemical Soc., Vol. 140A, pp. 1218-1225.
  10. Nguyen, T.V. and White, R.E., 1993, "A Water and Heat Management Model for Proton-Exchange Membrane Fuel Cells," J Electrochemical Soc. Vol. 140A, pp. 2178-2186.
  11. Okada, T., Xie, G. and Tanabe, Y., 1996, "Theory of Water Management at the Anode Side of Polymer Electrolyte Fuel Cell Membranes," J Electrochemical Chemistry, Vol. 413, pp. 49-65. https://doi.org/10.1016/0022-0728(96)04669-4
  12. Gurau, V., Liu, H. and Kakac, S., 1998, "Two - Dimensional Model for Proton Exchange Membrane Fuel Cells," AIChE, Vol. 44, pp. 2410-2422. https://doi.org/10.1002/aic.690441109
  13. Garau, V., Fabir, F. and Liu, H., 2000, "An Analytical Solution of a Half-Cell Model for PEM Fuel Cells," J Electrochemical Soc. Vol. 147A, pp. 2468-2477.
  14. Zamel, N. and Li, X., 2008, "A Parametric Study of Multi-Phase and Multi-Species Transport in the Cathode of PEM Fuel Cells," International Journal of Energy Research, Vol. 32, pp. 698-721. https://doi.org/10.1002/er.1384
  15. Zamel, N. and Li, X., 2010, "Non-Isothermal Multi-Phase Modeling of PEM Fuel Cell Cathode," International Journal of Energy Research, Vol. 34, pp. 568-584.
  16. Meng, H., 2007, "A Two-Phase Non- Isothermal Mixed-Domain PEM Fuel Cell Model and Its Application to Two-Dimensional Simulations," Journal of Power Research, Vol. 168, pp. 218-228.
  17. Kim, S. and Hong, I., 2007, "Effect of Flow Field Design on the Performance of a Proton Exchange Membrane Fuel Cell(PEMFC)," J of Ind. Eng. Chem, Vol. 13, No 5, pp. 864-869.
  18. Ahn, D., Han, S., Kim, K. and Chi, Y., 2009, "Experimental Analysis for Variation of Pressure Difference on Flooding in PEM Fuel Cell at Cathode Channel Oulet," Trans of the Korean Hydrogen and New Energy Society, Vol. 20, No. 5, pp. 390-396.

Cited by

  1. Variation of Porosity and Gas Permeability of Gas Diffusion Layers Under Compression vol.37, pp.8, 2013, https://doi.org/10.3795/KSME-B.2013.37.8.767
  2. PEMFC Optimization Design Using Genetic Algorithm vol.38, pp.11, 2014, https://doi.org/10.3795/KSME-B.2014.38.11.889