• Title/Summary/Keyword: PEM (Polymer electrolyte membrane) Fuel cell

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Soft Sensor Development for Predicting the Relative Humidity of a Membrane Humidifier for PEM Fuel Cells (고분자 전해질 연료전지용 막가습기의 상대습도 추정을 위한 소프트센서 개발)

  • Han, In Su;Shin, Hyun Khil
    • Transactions of the Korean hydrogen and new energy society
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    • v.25 no.5
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    • pp.491-499
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    • 2014
  • It is important to accurately measure and control the relative humidity of humidified gas entering a PEM (polymer electrolyte membrane) fuel cell stack because the level of humidification strongly affects the performance and durability of the stack. Humidity measurement devices can be used to directly measure the relative humidity, but they cost much to be equipped and occupy spaces in a fuel cell system. We present soft sensors for predicting the relative humidity without actual humidity measuring devices. By combining FIR (finite impulse response) model with PLS (partial least square) and SVM (support vector machine) regression models, DPLS (dynamic PLS) and DSVM (dynamic SVM) soft sensors were developed to correctly estimate the relative humidity of humidified gases exiting a planar-type membrane humidifier. The DSVM soft sensor showed a better prediction performance than the DPLS one because it is able to capture nonlinear correlations between the relative humidity and the input data of the soft sensors. Without actual humidity sensors, the soft sensors presented in this work can be used to monitor and control the humidity in operation of PEM fuel cell systems.

Numerical Simulation on Cooling Plates in a Fuel Cell (연료전지 냉각판의 냉각 특성에 대한 수치해석적 연구)

  • Kim, Yoon-Ho;Lee, Yong-Taek;Lee, Kyu-Jung;Kim, Yong-Chan;Choi, Jong-Min;Ko, Jang-Myoun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.1
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    • pp.86-93
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    • 2007
  • The PEM (polymer electrolyte membrane) fuel cell is one of the promising fuel cell systems as a new small power generating device for automobiles and buildings. The optimal design of cooling plates installed between MEA (membrane electrode assembly) is very important to achieve high performance and reliability of the PEMFC because it is very sensitive to temperature variations. In this study, six types of cooling plate models for the PEMFC including basic serpentine and parallel shapes were designed and their cooling performances were analyzed by using three-dimensional fluid dynamics with commercial software. The model 3 designed by revising the basic serpentine model represented the best cooling performance among them in the aspect of uniformity of temperature distribution and thermal reliability, The serpentine models showed higher pressure drop than the parallel models due to a higher flow rate.

Analysis of the Effects of CO Poisoning and Air Bleeding on the Performance of a PEM Fuel Cell Stack using First-Order System Model (일차계 모델을 이용한 고분자전해질 연료전지 스택의 CO Poisoning 및 Air Bleeding 효과 분석)

  • Han, In-Su;Shin, Hyun Khil
    • Korean Chemical Engineering Research
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    • v.51 no.3
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    • pp.370-375
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    • 2013
  • We analyze the effects of CO poisoning and air bleeding on the performance of a PEM (polymer electrolyte membrane) fuel cell stack fabricated using commercial MEA (membrane electrode assembly). Dynamic response data from the experiments on the performance of a stack are identified by obtaining steady-state gains and time-constants of the first-order system model expressed as a first-order differential equation. It is found that the cell voltage of the stack decreases by 1.3-1.6 mV as the CO concentration rises by 1 ppm. The time elapsed to reach a new steady state after a change in the CO concentration is shortened as the magnitude of the change in the CO concentration increases. In general, the steady-state gain becomes bigger and the time-constant gets smaller with increasing the air concentration (air-bleeding level) in the reformate gas to restore the cell voltage. However, it is possible to recover 87%-96% of the original cell voltages, which are measured with free of CO, within 1-30 min by introducing the bleed air as much as 1% of the reformate gas into the stack.

Study on PEM-Fuel-Cell Humidification System Consisting of Membrane Humidifier and Exhaust Air Recirculation Units (막가습기와 공기극 재순환을 사용한 고분자 전해질 연료전지의 가습특성 해석)

  • Byun, Su-Young;Kim, Beom-Jun;Kim, Min-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.4
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    • pp.337-344
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    • 2011
  • The humidification of reactant gases is crucial for efficiently operating PEM (polymer electrolyte membrane) fuel cell systems and for improving the durability of these systems. The recycle of the energy and water vapor of exhaust gas improves the system performance especially in the case of automotive application. The available humidification methods are steam injection, nozzle spray, humidification by enthalpy wheel, membrane humidifier, etc. However, these methods do not satisfy certain requirements such as compact design, efficient operation and control. In this study, a hybrid humidification system consisting of a membrane humidifier and exhaust-air recirculation units was developed and the humidification performance of this hybrid humidifier was analyzed. Finally, a new practical method for optimal design of PEM-fuel-cell humidification system is proposed.

Optimal Design of Bipolar-Plates for a PEM Fuel Cell (고분자 전해질 연료전지용 분리판 최적 설계)

  • Han, In-Su;Jeong, Jee-Hoon;Lim, Jong-Koo;Lim, Chan;Jung, Kwang-Sup
    • 한국신재생에너지학회:학술대회논문집
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    • pp.99-102
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    • 2006
  • Optimal flow-field design of bipolar-plates for a commercial class PEM(polymer electrolyte membrane) fuel cell stack was carried out on the basis of three-dimensional computational fluid dynamics(CFD) simulation. A three-dimensional CFD model originally developed by Shimpalee et al., has been utilized for performing large-scale simulation of a single fuel cell consisting of bipolar-plates gas diffusion layers, and a membrane-electrode-assembly(MEA). The CFD model is able to predict the current density, pressure drops, gas velocities, vapor and liquid water contents, temperature distributions, etc. inside a single fuel cell. Depending on simulation results from the CFD modeling of a PEM fuel cell, several flow-fields of bipolar-plates were designed and verified. The final design of the bipolar-plate has been chosen from the simulations and experimental tests and showed the best performance as expected from the simulation results under a normal operating condition. Thus, the CFD simulation approach to design the optimal flow-field of the bipolar-plates was successful. The final design was adopted as the best flow-field to build a commercial scale PEM fuel cell stack, the performance of which shows about 42% higher than that of the older bipolar-plate design.

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Modeling of PEM Fuel Cell System-Sensitivity Analysis of System Efficiency with Different Main Operating Parameters of Automotive Fuel Cell System (PEM 연료전지 시스템 모델링-자동차용 연료전지 시스템의 주요 작동 변수 변경에 따른 시스템 효율 민감도 분석)

  • KIM, HAN-SANG;KANG, BYUNGGIL;WON, KWONSANG
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.5
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    • pp.401-410
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    • 2019
  • The operating conditions greatly impact the efficiency and performance of polymer electrolyte membrane (PEM) fuel cell systems and must be properly managed to ensure better performance and efficiency. In particular, small variations in operating conditions interact with each other and affect the performance and efficiency of PEM fuel cell systems. Thus, a systematic study is needed to understand how small changes in operating conditions affect the system performance and efficiency. In this paper, an automotive fuel cell system (including cell stack and balance of plant [BOP]) with a turbo-blower was modeled using MATLAB/Simulink platform and the sensitivity analyses of main operating parameters were performed using the developed system model. Effects of small variations in four main parameters (stack temperature, cathode air stoichiometry, cathode pressure, and cathode relative humidity) on the system efficiency were investigated. The results show that cathode pressure has the greatest potential impact on the sensitivity of fuel cell system efficiency. It is expected that this study can be used as a basic guidance to understand the importance of achieving accurate control of the fuel cell operating conditions for the robust operation of automotive PEM fuel cell systems.