• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.5
• /
• pp.50-55
• /
• 2010

In recent years, the development of fuel cell vehicles has further accelerated because of environmental problem and petroleum resources shortage. The fuel cell vehicles have the stack which converts fuel to electricity. The stack is usually mounted by bush to isolate the vibration of chassis and body. This paper analyzed the vibratory characteristics of stack and chassis, body system. The wheel forces of fuel cell vehicle are measured to estimate the road load data. And the paths of vibration from wheel to stack are analyzed by CAE. According to the test and CAE results, the improvement of stack vibration are evaluated.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.553-556
• /
• 2007

Hyundai${\cdot}$Kia Motors have developed PEMFC stack technologies for passenger car application in 1998. The developed 80kW class stack, which was installed Kia's Sportage FCV in 2005, has been modified for -10$^{\circ}C$ cold start-up and ensuring the stability and durability by using new technologies such as newly designed separator, manifold block, end plate, and so on. And also, the stack durability has been verified over 1,500hrs with the condition of combined vehicle driving mode. Hyundai${\cdot}$Kia Motors will keep continuing the stack R&D to reach the goal of FCV commercialization.

• Korean Chemical Engineering Research
• /
• v.60 no.1
• /
• pp.12-19
• /
• 2022

Cathode open-type PEMFC (Proton Exchange Membrane Fuel Cells) stacks, which are widely used in small transport-type PEMFC, have a problem with poor durability. Through the accelerated durability test of the 13-cell PEMFC stack, we tried to find the cause of the degradation of the stack and to contribute to the improvement of the durability of the cathode open stack. A hydrogen/air boundary is formed during start-up/shut-down (SU/SD) due to the structural problem of the cathode open stack in which the cathode is open to the atmosphere and it is difficult to maintain airtightness, thereby deteriorating the cathode. In this study, it was possible to evaluate the durability in a relatively short time by reducing the 54% of the initial performance by repeating SU/SD 1,800 times on the cathode open stack. After dismantling the stack, each cell was divided into two and the performance was analyzed. Overall, the anode outlet MEA, which facilitates air inflow, showed more severe electrode deterioration than the inlet MEA, confirming that the hydrogen/air boundary formation during SU/SD is the main cause of degradation.

• Transactions of the Korean hydrogen and new energy society
• /
• v.32 no.5
• /
• pp.315-323
• /
• 2021

The air-cooled proton exchange membrane fuel cells (PEMFC) stacks, which is widely used in small-sized PEMFC, have a problem in that durability is weaker than that of the water-cooled type. Because the cathode is open to the atmosphere and the structural problem of the air-cooled stack, which is difficult to maintain airtightness, is highly likely to form a hydrogen/air boundary during start-up/shut-down (SU/SD). Through the accelerated durability evaluation of the 20 W air-cooled PEMFC stack, the purpose of this study was to find out the cause of the degradation of the stack and to contribute to the improvement of the durability of the air-cooled PEMFC stack. In this study, it was possible to evaluate durability in a relatively short time by reducing 20-30% of initial performance by repeating SU/SD 1,000 to 1,200 times on an air-cooled PEMFC stack. After disassembling the stack, each cell was divided into two and the performance analysis showed that the electrode degradation was more severe in the anode outlet membrane electrode assembly (MEA), which facilitates air inflow as a whole, than in the inlet MEA. It was shown that the cathode Pt was dissolved/precipitated to deteriorate the polymer ionomer inside the membrane.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.557-560
• /
• 2007

The durability of 80 kW class stack module was tested in hydrogen recirculation and non-recirculation systems with the condition of 300Amps (constant current mode) and hydrogen pulse purging (10 seconds close/0.8 seconds open). A localized membrane failure in the interfacial area between membrane and sub-gasket, carbon corrosion in cathode electrode, and Pt dissolution/extraction have been found through the post mortem analysis such as CV, Impedance, SEM, and so on. The main reason of these mechanisms will be discussed in this study.

• Transactions of the Korean hydrogen and new energy society
• /
• v.27 no.2
• /
• pp.144-154
• /
• 2016

HT-PEMFC (high temperature polymer electrolyte membrane fuel cell) using PA (phosphoric acid) doped PBI (polybenzimidazole) membrane has been researched for extending the lifetime. However, the existing work on durability of HT-PEMFC focuses on identifying degradation causes of lab scale. The short life time of HT-PEMFC is still the problem for its commercialization. In this paper, an operating method to maximize life time of 5kW HT-PEMFC stack are proposed. The proposed method includes major steps such as minimization of OCV (Open Circuit Voltage) exposure, control of the proper stack temperature, and N2 purging for the stack. This long life operating method was based on the fragmentary results of degradation from previous research works. Experimentally, the 5 kW homemade HT-PEMFC stack was operated for a long time based on the proposed method and the stack successfully can operate within the desired degradation rate for the target life time.

• Prospectives of Industrial Chemistry
• /
• v.22 no.4
• /
• pp.1-12
• /
• 2019

최근 전 세계적으로 이상화탄소 배출규제에 대응하기 위해 신에너지를 동력원으로 하는 자동차에 관심이 증가하고 있다. 그중 이온 교환막 연료전지(PEMFC)는 내연기관을 대신에 자동차 동력원으로 많이 사용되어지고 있으며 양산화를 위한 노력을 전 세계적으로 하고 있다. 하지만 이러한 수소 자동차가 시장과 소비자의 요구 조건을 충족하기 위해서는 내구성을 개선하여야 한다. 현재 선진사들을 중심으로 수소 자동차의 내구성을 개선하기 위해 노력하지만, 대부분 실험적 방법으로 내구성의 분석 및 평가를 수행하고 있다. 하지만, 이러한 방법은 비용과 시간이 많이 들기 때문에 경제적이지 못하다. 본 기고문에서는 내구성에 영향을 받는 인자, 연료전지 시스템 내구성을 예측하고 평가할 수 있는 수소 자동차 내구성 모델 개발에 필요한 수식에 관한 연구, 그리고 내구성 개선을 위한 해석적 방법(simulation)에 관한 연구 동향을 소개하고자 한다.

• Transactions of the Korean hydrogen and new energy society
• /
• v.26 no.2
• /
• pp.127-135
• /
• 2015

High-Temperautre Polymer Electrolyte Membrane Fuel Cell (HT-PEMFC) with phosphoric acid-doped polybenzimidazole (PBI) membrane has high power density because of high operating temperature from 100 to $200^{\circ}C$. In fuel cell stack, heat is generated by electrochemical reaction and high operating temperature makes a lot of heat. This heat is caouse of durability and performance decrease about stack. For these reasons, heat management is important in HT-PEMFC. So, we developed HT-PEMFC model and study heat flow in HT-PEMFC stack. In this study, we placed coolant plate number per cell number ratio as variable and analysed heat flow distribution in stack.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.125.1-125.1
• /
• 2010

A high efficiency polymer electrolyte membrane (PEM) fuel cell stack was developed for pressurized pure hydrogen and oxygen supplying conditions. The design objective for the cell stack was to maximize the electric efficiency and to minimize exhaust-gas emissions from it simultaneously. To achieve this objective, the cell stack was designed to use pure hydrogen and oxygen as fuel and oxidant, respectively, and to be operated under high gas inlet pressures and in a stage-wise dead-end operation mode. Major components constituting the cell stack, such as membrane electrode assembly, bipolar-plate, and gasket, have been developed to meet a target durability even in severe operating conditions: high gas inlet pressures and usage of pure oxygen. A high-power fuel cell stack was assembled using these components to verify the performance. The cell stack showed a good performance in terms of the efficiency and maximum power output.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.7
• /
• pp.76-83
• /
• 2014

During PEMFC(Proton Exchange Membrane Fuel Cell) operation monitoring and diagnosis are important issues for reliability and durability. Stack defect can be followed by a critical cell voltage drop in the stack. One method for monitoring the cell voltage is CVM(Cell Voltage Monitoring), where all cells in the stack are electrically connected to a voltage measuring system and monitored these voltages. The other methods are based on the EIS(Electrochemical Impedance Spectroscopy) and on nonlinear frequency response. In this paper, intermodulation(IM) method for diagnosis PEMFC stack is introduced. To detect one or more critical PEMFC cell voltage PEMFC stack is excited by two or more test sinusoid current, and the frequency response of the stack voltage is analyzed. If one or more critical cell voltage exists, higher harmonics on the voltage frequency spectrum will appear. For the proposed IM method, stack simulation and experiments are conducted.