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The Fabrication and System Optimization of Polymer Electrolyte Membrane Fuel Cell Stack

Title
The Fabrication and System Optimization of Polymer Electrolyte Membrane Fuel Cell Stack
Translated Title
고분자 전해질 연료전지 스택 제작 및 시스템 최적화
Authors
Hwang, Sun Wook
DGIST Authors
Hwang, Sun Wook; Lee, Ho Chun; Choi, Gyeung Ho
Advisor(s)
Lee, Ho Chun
Co-Advisor(s)
Choi, Gyeung Ho
Issue Date
2013
Available Date
2016-05-18
Degree Date
2013. 2
Type
Thesis
Keywords
Polymer Electrolyte Membrane Fuel Cell StackThermal distributionClamping pres-sureOperating conditionsStack Fabrication고분자 전해질 연료전지 스택온도 분포스택 쪼임 압력연료전지 동작 조건
Abstract
The polymer electrolyte membrane fuel cell (PEMFC) is a promising energy conversion tech-nology for future sustainable development. The PEMFC has many advantages such as high power density, low operating temperatures, low emissions, silent operation, and fast start-up and shut-down. Furthermore, it has infinite possibilities for use in a wide and variety of applications from small scale mobile devices and robots to large scale cars and power plants. Many research groups in the world have been investigating about PEMFCs, but they have mainly focused on the single cell level or material properties. PEMFC Stack or system level studies are very important topics for fuel cell applications, because the performance of single cells and the performance of stacks are totally different. The stack consists of single cells but it is not as simple as stacking of single cells. In this study, to make a more effective stack, I tried to analyze the thermal distribution of the bi-polar plate of the stack in terms of three designs: (1) 100cm2 rectangular bi-polar plate, (2) 200cm2 square cell bi-polar plate, and (3) 200cm2 alternative square design bi-polar plate. I also employed four methods: (1) 100cm2 rectangular bi-polar plate without cooling, (2) 100cm2 rectan-gular bi-polar plate with water cooling, (3) 200cm2 square cell bi-polar plate with air cooling, and (4) 200cm2 alternative square design bi-polar plate with air cooling using COMSOL simulations. To optimize clamping pressure at the stack assembly, stack clamping pressure conditions were: (1) single cell 5000N axial load, (2) single cell 50 in lb bolt torque, (3) single cell 90 in lb bolt torque, (4) 16 cell stack 5000N axial load, and (5) 16 cell stack 90 in lb bolt torque. These pressure conditions have been analyzed by solid-works simulation and experimental load tests with pres-sure sensitive films. Furthermore, to find optimal stack operating conditions, I evaluated stack per-formance depends on gas and stack temperature: 40, 50, 60, and 70℃, relative humidity: dry, 60,80, and 100%, and pressure conditions: 0psi, 10psi, 20psi, and 30psi. In thermal distribution analysis, 100cm2 rectangular bi-polar plate with water cooling and 200cm2 alternative square design bi-polar plate with air cooling show well distributed simulation result. The temperature differences of two design are around 2℃ in the simulation. The clamping pressure simulation and experiments are present pressure distributions in every layer in the stack. The big-gest pressure was applied at end plate and gasket, bipolar plate, MEA, GDL in this order. The op-timal conditions of this stack from experiments are operation at 10psi pressure, 60% relative hu-midity of react gases, and 70℃ stack temperature. ⓒ 2013 DGIST
Table Of Contents
1.Introduction 1 -- 1.1 Understanding PEMFC Stacks 2 -- 1.2 Motivation and Objectives 5 -- 1.2.1 Motivation for research 5 -- 1.2.2 Objectives 6 -- 1.3 Studies of PEMFC Stacks 6 -- 1.3.1 Thermal Management 7 -- 1.3.2 Clamping Pressure 11 -- 1.3.3 Parametric Studies of PEMFC Stacks 17 -- 2. Experiments 23 -- 2.1 Thermal Distribution Management 23 -- 2.1.1 Secondary Current Distribution 26 -- 2.1.2 Transport of Concentrated Species 28 -- 2.1.3 Free and Porous Media Flow 29 -- 2.1.4 Heat Transfer 31 -- 2.2 Clamping Pressure Optimization 32 -- 2.2.1 Computer Simulation 32 -- 2.2.2 Experimental Load Testing 34 -- 2.3 Fuel Cell Evaluation System 37 -- 2.3.1 Overview of the Fuel Cell Evaluation System 37 -- 2.3.2 The External Dew Point Humidifier 39 -- 2.3.3 Stack Preparation and Assembly 41 -- 2.3.4 Experiment Apparatus 50 -- 3. Results and Discussion 54 -- 3.1 Thermal Distribution Management Simulation Result 54 -- 3.1.1 100 cm2 Cell without Cooling; Case 1 54 -- 3.1.2 100 cm2 Cell with Water Cooling; Case 1 57 -- 3.1.3 200 cm2 Square Cell with Air Cooling; Case 2 61 -- 3.1.4 200 cm2 Alternative Square Cell with Air Cooling; Case 3 64 -- 3.2 Clamping Pressure Result 68 -- 3.2.1 Single Cell with 5000 Newton Axial Load 68 -- 3.2.2 Single Cell with 50 Inch Pounds Torque 69 -- 3.2.3 Single Cell with 90 Inch Pounds Torque 71 -- 3.2.4 Fuel Cell Stack, 16 Cells, 5000 Newton, all layers 73 -- 3.2.5 Fuel Cell Stack, 16 Cells, 90 Inch Pounds per Bolt, all layers 78 -- 3.2.6 Experimental Load Testing 84 -- 3.3 Operating Conditions of PEMFC Stacks 88 -- 3.3.1 Initial Tests 90 -- 3.3.2 Back Pressure Optimization. 92 -- 3.3.3 Relative Humidity Optimization 98 -- 3.3.4 Stack Operating Temperature Optimization 100 -- 4. Summary and Conclusion 106 -- References 110 -- Appendix A 119 -- 요약문 126
URI
http://dgist.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=000002262500
http://hdl.handle.net/20.500.11750/1336
DOI
10.22677/thesis.2262500
Degree
Master
Department
Energy Systems Engineering
University
DGIST
Files:
Collection:
Energy Science and EngineeringThesesMaster


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