KS C 8569 기반의 연료전지시스템 성능평가 및 그 운영에 관한 고찰

차정은(Jung-Eun Cha),이남진(Nam Jin Lee),최영우(Young-Woo Choi),윤영기(Young Ki Yoon),김원배(Won Bae Kim) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

연료전지는 수소와 산소로부터 전기화학 반응을 통해 직접 전기를 생산하는 발전장치로, 연료전지 시스템은 연료전지 스택, 연료변환기, 주변기기(MBOP: Mechanical Balance of Plant, EBOP: Electrical Balance of Plant) 및 제어기술을 포함한다. 연료전지 보급이 확대되면서, 안전과 성능 검증을 위한 표준이 요구되었으며, 이에 따라 표준서 KS C 8569는 2015 년 고분자연료전지(PEMFC) 시스템에 대하여 KS 제정을 시작으로 2019 년에는 직접 메탄올 연료전지(DMFC)시스템을, 2020 년에는 고체고분자연료전지(SOFC)시스템을 포함함으로써 현재의 표준서가 완성되었다. KS C 8569는 발전효율, 열효율, 기동/정지 특성, 부하변동 등을 포함하는 성능평가와 온도상승, 절연, 계통 보호, 내전기환경시험 등의 안정성 평가, 그리고 배출가스, 소음측정 등 환경성 평가로 구분되며, 총 49 개 상세항목으로 구성되어 있다. 초반 4 개 기업의 정지형, 즉 건물용 PEMFC 연료전지시스템의 KS 인증을 시작으로 현재 SOFC까지 포함하여 13 여개 기업으로 확장되었다. 또한, 초반에 1 kW 급 이하의 시스템이 대부분이었으나 2017 년 이후부터는 5 kW이상, 최근에는 10 kW 시스템이 주력을 이루고 있다. 하지만, 지금의 표준서는 기존의 정지형에서 이동형을 결합한 것으로 평가내용이 혼재되고, 이동형의 기본성능 (직류), 내열, 충격, 진동, 냉온 등의 안전성 검사 기준이 미흡하다. 또한, 정지형의 경우 10kW 급 이하로 규정되어 있어서 100 kW 이하의 과도기적인 시장 제품에 적합하지 못하다. 따라서, KS C 8569를 재정비하고, 국제표준과의 부합화를 통하여 국내 연료전지 산업 육성과 더불어 수출전략 고도화 가능성을 모색해야한다. The fuel cell is one of the power generating systems converting the chemical energy of hydrogen and oxygen into electricity through a pair of redox reactions, which mainly consists of a fuel reformer, cell stack, and an inverter. With the expansion of the supply of fuel cell systems, test standards and certifications have been required to verify the safety and performance of fuel cells. Starting with KS certification for polymer electrolyte membrane fuel cell (PEMFC) systems in 2015, KS C 8569 has been completed by including direct methanol fuel cell (DMFC) systems in 2019 and solid oxide fuel cell (SOFC) systems in 2020. This certification is divided into the performance assessment including power generation efficiency, thermal efficiency, start-up/shut-down characteristics, stability evaluation for the increase in temperature, electric resistance test, and the environmental assessment such as emissions and noise measurements. Initially, four fuel cell system manufacturers obtained KS certification for the stationary system, and now it has been expanded to a total of 13 companies including SOFC and DMFC system manufacturing companies. Besides, most of the systems were 1 kW or lower in the beginning, however since 2017, the capacity has increased to 5 kW or higher, and 10 kW systems have recently become the main focus. However, this standard has been revised to add the mobile fuel cell system standard to the existing stationary fuel cell standard, which lacks basic performance (direct current), heat resistance, shock, vibration, cold and hot tests that conform to the mobile fuel cell system standard. In addition, stationary fuel cell systems are not suitable for transition market products under 100 kW because they are defined as less than 10 kW. Accordingly, KS C 8569 should be reviewed to suit international standards and transitional market products to promote the domestic fuel cell industry and seek the possibility of upgrading its export strategy.

Effects of anode flooding on the performance degradation of polymer electrolyte membrane fuel cells

Kim, Mansu,Jung, Namgee,Eom, KwangSup,Yoo, Sung Jong,Kim, Jin Young,Jang, Jong Hyun,Kim, Hyoung-Juhn,Hong, Bo Ki,Cho, EunAe Elsevier 2014 Journal of Power Sources Vol.266 No.-

<P><B>Abstract</B></P> <P>Polymer electrolyte membrane fuel cell (PEMFC) stacks in a fuel cell vehicle can be inevitably exposed to harsh environments such as cold weather in winter, causing water flooding by the direct flow of condensed water to the electrodes. In this study, anode flooding was experimentally investigated with condensed water generated by cooling the anode gas line during a long-term operation (∼1600 h). The results showed that the performance of the PEMFC was considerably degraded. After the long-term experiment, the thickness of the anode decreased, and the ratio of Pt to carbon in the anode increased. Moreover, repeated fuel starvation of the half-cell severely oxidized the carbon surface due to the high induced potential (>1.5 V<SUB>RHE</SUB>). The cyclic voltammogram of the anode in the half-cell experiments indicated that the characteristic feature of the oxidized carbon surface was similar to that of the anode in the single cell under anode flooding conditions during the long-term experiment. Therefore, repeated fuel starvation by anode flooding caused severe carbon corrosion in the anode because the electrode potential locally increased to >1.0 V<SUB>RHE</SUB>. Consequently, the density of the tri-phase boundary decreased due to the corrosion of carbons supporting the Pt nanoparticles in the anode.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Anode flooding can occur by direct flow of condensed water in humidified fuel. </LI> <LI> Anode flooding induces local fuel starvation and high potential in the anode. </LI> <LI> High potential locally present in the anode results in anode carbon corrosion. </LI> <LI> Anode carbon corrosion plays a key role in MEA degradation by anode flooding. </LI> </UL> </P>

DSP기반 연료전지 하드웨어 시뮬레이터 구현

엄준현(Jun-Hyun Oum),임영철(Young-Cheol Lim),정영국(Young-Gook Jung) 한국조명·전기설비학회 2009 조명·전기설비학회논문지 Vol.23 No.1

분산전원으로서 연료전지 발전장치는 100w부터 수백[㎾]의 용량을 가지며 종전의 대규모 전력설비와 비교하여 높은 신뢰도를 갖는 고품질의 전력을 공급할 수 있다. 본 연구에서는 소형 분산전원으로서 PEMFC(polymer electrolyte membrane fuel cell)연료전지 발전장치에 대한 PSIM(power electronics simulation tool) 모델을 설정하고 이를 바탕으로 DSP(digital signal processor)기반의 연료전지 하드웨어 시뮬레이터를 구현하였다. 연료전지 전류와 출력진압과의 관계는 연료전지의 전압-전류(V-I) 곡선 중 ohmic영역에서 1차 함수로 간략화 하였다. 구현된 시스템은 PEMFC 하드웨어 시뮬레이터, 절연형 풀 브리지 직류 부스트 컨버터 그리고 60[㎐] PWM인버터로 구성 되어있다. 부하변동 및 과도상태에 대한 연료전지 하드웨어 시뮬레이터의 전압-전류-전력(V-I-P) 특성을 파악하였으며, 저항 부하 및 비선형 부하에 대한 전력변환기의 60[㎐] 정현파 교류출력 전압파형을 고찰하였다. Fuel cell generators as the distributed generation system with a few hundred watt-a few hundred kilowatt capacity, can supply the high quality electric power to user as compared with conventional large scale power plants. In this paper, PEMFC(polymer electrolyte membrane fuel cell) generator as micro-source is modelled by using PSIM simulation software and DSP based fuel cell hardware simulator based on the PSIM simulation model is implemented. The relation of fuel cell voltage and current[V-I] curve) is linearized by first order function on the ohmic area in voltage-current curve of fuel cell. The implemented system is composed of a PEMFC hardware simulator, an isolated full bridge de boost converter, and a 60[㎐] voltage source PWM inverter. The voltage-current-cower(V-I-P) characteristics of the implemented fuel cell hardware simulator are verified in load variation and transient state and the 60[㎐] output voltage sinusoidal waveform of the PWM inverter is investigated under the resistance load and nonlinear diode load.

Lifetime prediction of a polymer electrolyte membrane fuel cell via an accelerated startup–shutdown cycle test

Bae, Suk Joo,Kim, Seong-Joon,Park, Jong In,Park, Chan Woong,Lee, Jin-Hwa,Song, Inseob,Lee, Naesung,Kim, Ki-Bum,Park, Jun-Young Elsevier 2012 International journal of hydrogen energy Vol.37 No.12

<P><B>Abstract</B></P><P>To expand commercial applications of polymer electrolyte membrane fuel cells (PEMFCs), the evaluation time for their durability must be shortened. This article provides a straightforward accelerated degradation testing (ADT) procedure for PEMFC for easy and quick implementation of the procedure. The ADT procedure includes statistical modeling of degradation patterns of membrane electrode assemblies (MEAs) in PEMFCs under startup–shutdown cycling conditions. For this purpose, we propose a nonparametric degradation model to describe the nonlinear performance degradation paths of PEMFC MEAs. The analysis results indicate that the nonparametric approach provides more accurate estimates of the observed degradation data than other parametric approaches. Based on the nonparametric degradation model, we suggest a method to predict failure-times under normal operating conditions by estimating the time-scale factor under accelerated operating conditions.</P> <P><B>Highlights</B></P><P>► We provide a straightforward accelerated degradation testing procedure for PEMFC. ► We propose a nonparametric degradation model to describe the nonlinear performance degradation paths of PEMFC. ► We suggest a method to predict failure-times under normal operating conditions by estimating the time-scale factor.</P>

Implementation of discrete wavelet transform-based discrimination and state-of-health diagnosis for a polymer electrolyte membrane fuel cell

Kim, J.,Tak, Y. Pergamon Press ; Elsevier Science Ltd 2014 International journal of hydrogen energy Vol.39 No.20

This research investigates a new approach based on the discrete wavelet transform (DWT) that suitable for analyzing and evaluating output terminal voltage signal (OTVS) for discrimination analysis of a polymer electrolyte membrane fuel cell (PEMFC). Due to its ability for extracting information from the non-stationary and transient phenomena simultaneously in both time and frequency domain, the OTVS can be applied as source data in the DWT-based approach. By using the wavelet decomposition including the multi-resolution analysis (MRA) using the Daubechies wavelet (dB) as mother wavelet, the information on the electrochemical characteristics of a PEMFC can be extracted from the OTVS over a wide frequency range. Thus, the cells that have similar electrochemical characteristics can be eventually discriminated. In particular, this present research develops these investigations one step further by showing low-frequency components (approximation A<SUB>n</SUB>) and high-frequency components (detail D<SUB>n</SUB>) extracted from variable single cells with different electrochemical characteristics. Experimental results show that DWT-based approach is clearly appropriate for the reliable SOH diagnosis for a PEMFC.

Development of a 240 kW PEMFC system model for a ship

방은신,김영민,김명환,박상균 한국마린엔지니어링학회 2020 한국마린엔지니어링학회지 Vol.44 No.4

In this study, a system model of a marine 240-kW-class fuel cell using oxygen in a liquefied oxygen tank and compressed hydrogen as fuel was developed. The voltage and output characteristic data of the stack according to the change in fuel-cell loads were compared with the experimental results to validate the system. In addition, the system efficiency of the fuel-cell stack, the change in the coolant temperature of the stack, and the discharged-gas temperature on the cathode side were reviewed under various operating loads. As a result, the fuel-cell stack voltage was found to be up to ~4 V below the experimental results in some load areas within the range considered in this study; however, the obtained voltage was almost the same as that observed in the experimental results. The total stack output was calculated to be 250 kW at a maximum load of 530 A, the individual stack efficiency was 59%, and the system efficiency was 53%. Moreover, the PI controller was appropriately operated to maintain an average value of 343 K for the stack coolant temperature from fuel cell No. 1 stack and No. 2 stack.

고분자전해질 연료전지용 금속 바이폴라 플레이트의 표면코팅

윤영훈 ( Young Hoon Yun ) 조선대학교 공학기술연구원 2008 공학기술논문지 Vol.1 No.2

The metallic film and conductive oxide film were formed on stainless steel 316 and 304 plates by a puttering method and an E-beam method, respectively. Also, the external metallic region of the stainless steel bipolar plates was converted into the metal nitride films through an annealing process. Besides, the surface region of commercial stainless steel 304 and 316 plates was modified through tile deposition of the multi-layered coatings composed of titanium film (0.1 ㎛) and gold film (1-2 ㎛) by an electron beam evaporation method. The XRD patterns of the thin film on the stainless steel bipolar plates modified with the metallic film and conductive oxide showed two metal nitride phase of CrN and Cr2N compounds. The FE-SEM images of the metal nitride film, which was formed on stainless steel bipolar plates, clearly showed the microstructural morphology of fine columnar grains with 0.0 1 ㎛ diameter and 0.06 ㎛ length. On the other hand, the XRD pattern of the stainless steel plates deposited with conductive metal films showed the peaks of the external gold film and the stainless steel substrate, In case of the stainless steel plates modified with 0.1 ㎛ titanium film and 1 ㎛ gold film showed microstructure of grains of under 0.1 ㎛ diameter. Finally, the electrical resistance and water contact angle of the surface modified stainless steel bipolar plates were examined to investigate their applicability in preparing PEMFC.

PEMFC용 캐소드를 위한 Pt/C, PtCo/C 촉매제조 및 전기화학평가

김진환,류호진,Kim, Jin-Hwan,Ryu, Ho-Jin 한국반도체디스플레이기술학회 2008 반도체디스플레이기술학회지 Vol.7 No.4

For the commercialization of polymer electrolyte membrane fuel cell (PEMFC), some serious problems such as the decrease of platinum use as catalysts and a larger overpotential of oxygen reduction reaction (ORR) at cathode must be solved. In this study, 20%Pt/C and 20%PtCo/C catalysts for the cathode of PEMFC were synthesized from the chemical reduction method and evaluated using an electrochemical measurement. The ORR activity of synthesized 20%Pt/C and 20%PtCo/C had higher than that of the 20%Pt/C on the market. The synthesized 20%PtCo/C with the cobalt concentration (Pt:Co atomic ratio) from 5 to 20% showed the highest ORR activity.

Recent Developments of Polymer Electrolyte Membrane Fuel Cell Design

Wonchan Hwang,Yung-Eun Sung The Korean Electrochemical Society 2023 Journal of electrochemical science and technology Vol.14 No.2

PEMFC has high potential for future development due to its high energy density, eco-friendliness, and high energy efficiency. When it becomes small, light and flexible, it can be competitive as an energy source for portable devices or flexible electronic devices. However, the use of hard and heavy materials for structural rigidity and uniform contact pressure transmission has become an obstacle to reducing the weight and flexibility of PEMFCs. This review intends to provide an example of the application of a new structure and material for lightweight and flexibility. As a lightweight PEMFC, a tubular design is presented and structural advantages through numerical modeling are explained. Manufacturing methods to realize the structural advantages and possibilities of tubular PEMFCs are discussed. In addition, the materials and manufacturing processes used to fabricate lightweight and flexible PEMFCs are described and factors affecting performance are analyzed. Strategies and structural improvements of light and flexible movements are discussed according to the component parts.

Effect of ionomer content and relative humidity on polymer electrolyte membrane fuel cell (PEMFC) performance of membrane-electrode assemblies (MEAs) prepared by decal transfer method

Jeon, Sunyeol,Lee, Jisun,Rios, Gema M.,Kim, Hyoung-Juhn,Lee, Sang-Yeop,Cho, EunAe,Lim, Tae-Hoon,Hyun Jang, Jong Elsevier 2010 International journal of hydrogen energy Vol.35 No.18

<P><B>Abstract</B></P><P>Membrane-electrode assemblies (MEAs) were fabricated by the decal transfer method with various Nafion ionomer contents (10–40 wt%) and their single cell performance and electrochemical characteristics were examined in atmospheric air at relative humidities of 25–95%. At high humidity (95%), the MEA performance was the highest with a cathode ionomer content of 30 and 20 wt% at 0.6 and 0.4 V, respectively. The optimum ionomer content of the decal MEAs increased with decreasing humidity, because of the change in the oxygen transport rate (water flooding) and number of active sites (ionic resistance). The concentration overpotential gradually increased with relative humidity up to about 0.4 V at 0.8 A/cm<SUP>2</SUP>, which was not considered in previous studies using pressurized air and oxygen. The combined effect of the electrochemical active surface area and ionic resistance of the cathodes on the activation overpotential was also investigated, focusing on intermediate and low humidity levels, using a newly developed impedance analysis method.</P>