Effect of stack configuration on the performance of 10W PEMFC stack

임성대(Yim, Sung-Dae),김병주(Kim, Byung-Ju),손영준(Sohn, Young-Jun),윤영기(Yoon, Young-Gi),양태현(Yang, Tae-Hyun),김창수(Kim, Chang-Soo),김영채(Kim, Young-Chai) 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.06

A small PEM fuel cell has two different stack configurations such as active and passive stacks. The active stack has a distintion of high power density although it makes system complex by using alr blower and related BOPs resulting in large system volume. On the contrary, passive stack has an advantage of compact system because it doesn't need air supplying devices although it reveals relatively low stack power density. In this study we fabricated two 10W PEMFC stacks with different stack configurations, active and passive stacks, and tested their performance and stability. The active stack consists of 13cells with an active area of 5cm². The passive stack has 12cells with an active area of 16cm². When we compared the stack performance of those stacks, the active stack showed higher power density compared to the passive stack, particularly at high voltage regions. However, at low voltage and high current regions, the passive stack performance was comparable to the active stack. The stack stability was largely dependent on the fuel humidity, particularly for active stack. At low humidity conditions, the active stack performance was decreased continuously and the cell voltage distribution was not uniform showing seriously low cell voltage at center cells mainly due to the cell drying. The passive stack showed relatively stable behavior at low humidity and the stack performance was largely dependent on the atmospheric conditions.

주택용 연료전지 효율 향상Power Distribution Optimization of Multi-stack Fuel Cell Systems for Improving the Efficiency of Residential Fuel Cell을 위한 다중 스택 연료전지 시스템의 전력 분배 최적화

강태성,함성현,오환영,최윤영,김민진 한국수소및신에너지학회 2023 한국수소 및 신에너지학회논문집 Vol.34 No.4

The fuel cell market is expected to grow rapidly. Therefore, it is necessary to scale up fuel cells for buildings, power generation, and ships. A multi- stack system can be an effective way to expand the capacity of a fuel cell. Multi-stack fuel cell systems are better than single-stack systems in terms of efficiency, reliability, durability and maintenance. In this research, we developed a residential fuel cell stack and system model that generates electricity using the fuel cell-photovoltaic hybrid system. The efficiency and hydrogen consumption of the fuel cell system were calculated according to the three proposed power distribution methods (equivalent, Daisy-chain, and optimal method). As a result, the optimal power distribution method increases the efficiency of the fuel cell system and reduces hydrogen consumption. The more frequently the multi-stack fuel cell system is exposed to lower power levels, the greater the effectiveness of the optimal power distribution method.

A laminar flow-based single stack of flow-over planar microfluidic fuel cells

Lee, Seoung Hwan,Ahn, Yoomin Elsevier 2017 Journal of Power Sources Vol.351 No.-

<P><B>Abstract</B></P> <P>Power densities of microfluidic fuel cells are still not high enough for power source applications. In this study, we propose a novel planar stack to increase the total power of a microfluidic fuel cell. Electrical connections in serial or parallel are made within one channel by using multiple laminar flow. A planar structure with flow-over electrodes of platinum are adopted for easy integration with other planar micro devices. These structures are made by micromachining with a thin film process. Fuel cell performance and total ohmic resistances are measured experimentally with a formic acid-based fuel. The results show that the proposed single stacks provide more power density with a comparatively small total ohmic resistance and require less space than that of the fuel cell arrays. The peak volumetric power density improves by 97.5% and 39.3% using parallel and serial electrical connections, respectively, at a 300 μL min<SUP>−1</SUP> flow rate. Utilizing this single stack, we believe that microfluidic fuel cells can be integrated into a compact planar configuration to achieve a power high enough for energy source applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A planar single stack is proposed for electrical connections in series or parallel. </LI> <LI> The stack consisted of a modified bipolar electrode for planar scale-up. </LI> <LI> Multiple laminar flows are utilized to make the connections within one channel. </LI> <LI> The single stacks produce better cell performance than that of the cell array structure. </LI> <LI> Planar scale-up cell sizes are minimized by adopting the proposed single stacks. </LI> </UL> </P>

비정질/다결정규소 적층형 태양전지

김도영,김상수,박용관,이준신 成均館大學校 科學技術硏究所 1997 論文集 Vol.48 No.1

본 연구는 최근의 지상전력 응용을 위한 Metal/a-Si:H(n-i-p)/poly-Si(n-p)/Metal 구조를 가지는 적층형 태양전지를 연구하였다. 이 전지는 두 층의 동종접합이 적층된 전지구조로 구성되었다. 상부는 1.8eV의 큰 에너지 밴드갭을 가지는 n-i-p형 a-Si:H와 하부전지는 1.1eV의 작은 에너지 밴드갭의 다결정 규소 전지의 n-p형 접합이다. 태양전지의 효율 영향요소를 PC-1D 태양전지 모의실험을 통해 조사한후 실제 소자 제작에 적용하였다. 주요 연구 분야는 3가지로 구분되며 첫째는 p-n접합 다결정 규소의 하부 전지, 둘째는 p-i-n접합 수소화 비정질 상부규소, 세 번째로 적층형 전지의 계면층에 대한 영향이다. 하부전지의 효율은 900℃의 전열처리, 표면처리, 0.43㎛의 에미터 두께, 상부 Yb 금속, 7% 정도의 태양전지 그리드 면적으로 향상되었다. 최적화된 전지 공정으로부터 약 16%의 변환효율을 달성하였다. 상부전지는 이온에 의한 박막의 손상이 없고 우수한 p/i-a-Si:H 계면층을 가지는 광-CVD 시스템을 사용하여 성장하였다. 적층형 계면효과는 세가지의 화학적인 표면처리, 열산화에 의한 표면처리, 그리고 Yb 금속의 상태등의 경우를 연구하였다. 열산화막에 의해 표면처리된 전지는 높은 광전류의 생성과 향상된 분광반응도를 보이고 있다. We investigated multi-stacked solar cells with a structure of metal/a-Si:H(n-i-p)/ poly-Si(n-p)/metal for the terrestrial applications. This cell consists of two component cells: a top n-i-p junction a-Si:H cell with wide-bandgap 1.8eV and a bottom n-p junction poly-Si cell with narrow-bandgap 1.1eV. The efficiency influencing factors of the solar cell were investigated in terms of simulations and experiments. Three main topics of the investigated study were the bottom cell with n-p junction poly-Si, the top a-Si:H cell with n-i-p junction, and the interface layer effects of multi-stacked cell. The efficiency of bottom cell was improved with a pretreatment temperature of 900℃, surface polishing, emitter thickness of 0.43μm, top Yb metal, and grid finger shading of 7% coverage. The process optimized cell showed a conversion efficiency about 16%. Top cell was grown by using a photo-C JD system which gave an ion damage free and good p/i-a-Si:H layer interface. The multi-stacked interface effect was examined with three different surface states; a chemical passivation, thermal oxide passivation, and Yb metal. The oxide passivated cell exhibited the higher photocurrent generation and better spectral response.

Fabrication and operation of a 6 kWe class interconnector-type anode-supported tubular solid oxide fuel cell stack

Park, K.,Yoon, D.H.,Lee, S.,Kwon, T.h.,Bae, G.,Hyun, S.,Kwon, Y.,Won, J.,Suh, J.,Kim, J.,Lee, S.,Bae, J. Pergamon Press ; Elsevier Science Ltd 2014 International journal of hydrogen energy Vol.39 No.24

A 6 kW class interconnector-type anode-supported tubular solid oxide fuel cell (ICT SOFC) stack is fabricated and operated in this study. An optimized current-collection method, which the method for current collection at the cathode using the winding method and is the method for the connection between cells using interconnect, is suggested to enhance the performance of the fabricated cell. That method can increase the current collection area because of usage of winding method for cell and make the connection between cells easy. The performance of a single cell with an effective electrode area of 205 cm<SUP>2</SUP> exhibits 51 W at 750 <SUP>o</SUP>C and 0.7 V. To assemble a 1 kW class stack, the prepared ICT SOFC cells are connected in series to 20 cells connected in parallel (20 cells in series x two in parallel, 20S2P). Four modules are assembled for a 6 kWe class stack. For one module, the prepared ICT SOFC cells are connected in series to 48 cells, in which one unit bundle consists of two cells connected in parallel. The performance of the stack in 3% humidified H<SUB>2</SUB> and air at 750 <SUP>o</SUP>C exhibits the maximum electrical power of 7425 W.

Monolithic flat tubular types of solid oxide fuel cells with integrated electrode and gas channels

Park, Sungtae,Sammes, Nigel Mark,Song, Ki-Hun,Kim, Taewook,Chung, Jong-Shik Elsevier 2017 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.42 No.2

<P><B>Abstract</B></P> <P>A new monolithic solid oxide fuel cell (SOFC) design stacked with flatten tubes of unit cells without using metallic interconnector plate is introduced and evaluated in this study. The anode support is manufactured in a flat tubular shape with fuel channel inside and air gas channel on the cathode surface. This design allows all-ceramic stack to provide flow channels and electrical connection between unit cells without needing metal plates. This structure not only greatly reduces the production cost of SOFC stack, but also fundamentally avoids chromium poisoning originated from a metal plate, thereby improving stack stability. The fuel channel was created in the extrusion process by using the outlet shape of mold. The air channel was created by grinding the surface of pre-sintered support. The anode functional layer and electrolyte were dip-coated on the support. The cathode layer and ceramic interconnector were then spray coated. The maximum power density and total resistance of unit cell with an active area of 30 cm<SUP>2</SUP> at 800 °C were 498 mW/cm<SUP>2</SUP> and 0.67 Ωcm<SUP>2</SUP>, respectively. A 5-cell stack was assembled with ceramic components only without metal plates. Its maximum power output at 750 °C was 46 W with degradation rate of 0.69%/kh during severe operation condition for more than 1000 h, proving that such all-ceramic stack is a strong candidate as novel SOFC stack design.</P> <P><B>Highlights</B></P> <P> <UL> <LI> New design of all ceramic monolithic SOFC stack is proposed with flat-tubular cell. </LI> <LI> Two layers of thin ceramic interconnectors are developed and applied. </LI> <LI> The 5-cell stack exhibits a degradation rate of 0.69%/kh at 750 °C. </LI> </UL> </P>

3차원 CFD 시뮬레이션을 활용한 고분자전해질연료전지 스택의 매니폴드 크기 최적화

정지훈,한인수,신현길 한국수소및신에너지학회 2013 한국수소 및 신에너지학회논문집 Vol.24 No.5

Polymer electrolyte membrane (PEM) fuel cell stacks are constructed by stacking several to hundreds of unit cells depending on their power outputs required. Fuel and oxidant are distributed to each cell of a stack through so-called manifolds during its operation. In designing a stack, if the manifold sizes are too small, the fuel and oxidant would be maldistributed among the cells. On the contrary, the volume of the stack would be too large if the manifolds are oversized. In this study, we present a three-dimensional computational fluid dynamics (CFD) model with a geometrically simplified flow-field to optimize the size of the manifolds of a stack. The flow-field of the stack was simplified as a straight channel filled with porous media to reduce the number of computational meshes required for CFD simulations. Using the CFD model, we determined the size of the oxidant manifold of a 30 kW-class PEM fuel cell stack that comprises 99 cells. The stack with the optimal manifold size showed a quite uniform distribution of the cell voltages across the entire cells.

인산형 연료전지 스택에 대한 3차원 모사

안현식,김효 서울시립대학교 산업기술연구소 1999 산업기술연구소논문집 Vol.7 No.-

A fuel cell is an electrochemical device that can continuously convert the chemical energy of a fuel and an oxidant to electrical energy by processes involving essentially invariant electrode-electrolyte system. Phosphoric acid fuel cell employs concentrated phosphoric acid as an electrolyte. The cell stack in the fuel cell, which is a core component of the fuel cell system, is made up of anode, where oxidation of the fuel occurs; electrolyte, to separate the anode and cathode and to conduct the ions between them; and cathode where reduction of the oxidant occurs. Fuel cell performance is associated with many parameters; operating and design parameters associated with the system configuration. Hence, we have modeled the fuel cell stack and computed the temperature distribution and the concentration of reactants and products in the cell stack of a phosphoric acid fuel cell using the computational fluid dynamics technique. Computational results are capable of predicting fuel-cel3 stack performance and easy understanding the heat and mass diffusion in the fuel cell stack.

Technology of Fuel cell stack fault detection by THDA

김억수(Kim, UckSoo),박현석(Park, HyunSeok),강선두(Kang, SunDoo),엄정용(Eom, JeongYong) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

This technology is applicable to Electrical vehicle that using Energy from Hydrogen Fueled Cell. Electricity & water is got from chemical reaction between H2 & O2 in stack. This technology is used when fault diagnosis of Fuel cell is needed. It is General method that measure each cell's voltage of stack for fault diagnosis. but, this technology is method of measuring entire voltage of stack. For this reason, fault diagnosis system is simplified and cost of system is lower than previous one. In normal stack condition, characteristic graph of voltage-current has linearity. In fault stack condition, it has non-linearity. we use this characteristic to diagnosis of stack fault. In this technology, Specific frequency current is injected into stack & Stack voltage is measured in response. After that, stack voltage difference is analyzed to diagnosis of stack fault. Presently, Development of current injection module & basic program of THDA is finished. in future we will develop the technology of precise measurement technology about entire stack voltage.

Reliable sealing design of metal-based solid oxide fuel cell stacks for transportation applications

Lee, Sanghun,Jang, Young-hoon,Shin, Ho Yong,Lee, Kunho,Bae, Minseok,Kang, Juhyun,Bae, Joongmyeon Pergamon Press 2019 International journal of hydrogen energy Vol.44 No.57

<P><B>Abstract</B></P> <P>Recently, metal-based solid oxide fuel cells (SOFCs) receive much attention as new power converting systems, and reliable sealing is an essential requirement for the metal-based SOFC stacks. In this study, metal-based SOFC stacks with a reliable sealing method are developed for transportation applications. For successful development, bolt-spring and hydraulic compression methods for stack tightening are discussed in terms of their applicability to vehicles. Then, detailed stack designs are developed to obtain sufficient compressive stress on the surfaces of the sealing gaskets based on the finite element method (FEM). To maintain the compression and heat insulation of the stack, a hot box is designed based on the thermogravimetric properties, shrinkage behaviors, and mechanical properties of sealing gaskets of mica and Thermiculite 866LS, and ceramic fiber insulating board. As a result, a 1-cell stack unit is successfully fabricated and tested based on the designs, and a sealing rate of 100 ± 0.78% is achieved at an operating temperature of 800 °C. This study investigates comprehensive stack and sealing design processes, and it has broad implications for reliable stack development.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A metal-based solid oxide fuel cell stack was designed for reliable sealing. </LI> <LI> Bolt-spring and hydraulic compression methods were discussed for vehicles. </LI> <LI> Finite element analysis was conducted for sufficient stress on sealing gaskets. </LI> <LI> A hot box was designed to maintain compression and heat insulation of the stack. </LI> <LI> A sealing rate of 100% of 1-cell stack unit was achieved at a temperature of 800 °C. </LI> </UL> </P>