Impedance Analysis of Practical Segmented-in-Series Tubular Solid Oxide Fuel Cells

Fuel cells consist of single cells that are connected in series to form a stack. This increases output voltage and therefore decreases current-dependent power losses, but the electric current of the stack has to flow through each single cell. In case of an increase of resistance or a failure of just one single cell the whole stack is affected. The failure tolerance of a parallel connection is higher. The serial and parallel connection of single solid oxide fuel cells (SOFC) is compared under the aspects of failure probability, power drop and stress on the single cells. With both a highly linearized and a complex SOFC model simulations have been accomplished of the connection of two single cells in parallel and in serial configuration. Additionally different connection concepts of 16 single cells were examined. Finally, an outlook on different other source or storage technologies for electric energy like batteries and photovoltaic cells is given.

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Fabrication and Operation of Flat Tubular Segmented-in-Series(SIS) Solid Oxide Fuel Cells(SOFC)

ECS Meeting Abstracts ◽

10.1149/ma2013-01/4/270 ◽

2013 ◽

Keyword(s):

Fuel Cells ◽

Solid Oxide Fuel Cells ◽

Solid Oxide ◽

Oxide Fuel ◽

In Series

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Operation Characteristics of Tubular Segmented-In-Series Solid Oxide Fuel Cells (SOFC)

ECS Transactions ◽

10.1149/1.3570046 ◽

2019 ◽

Vol 35 (1) ◽

pp. 679-682

Author(s):

Tak-Hyoung Lim ◽

U. J. Yun ◽

Jong-Won Lee ◽

Seung-Bok Lee ◽

Seok-Joo Park ◽

...

Keyword(s):

Fuel Cells ◽

Solid Oxide Fuel Cells ◽

Solid Oxide ◽

Oxide Fuel ◽

In Series ◽

Operation Characteristics

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A study of electrically insulated oxide substrates for flat-tube segmented-in-series solid oxide fuel cells

Journal of Power Sources ◽

10.1016/j.jpowsour.2011.11.056 ◽

2012 ◽

Vol 202 ◽

pp. 114-119 ◽

Cited By ~ 8

Author(s):

T. Somekawa ◽

K. Horiuchi ◽

Y. Matsuzaki

Keyword(s):

Fuel Cells ◽

Solid Oxide Fuel Cells ◽

Solid Oxide ◽

Oxide Fuel ◽

Flat Tube ◽

Oxide Substrates ◽

In Series

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LSM Protective Coatings on Stainless Steel as Interconnects for Solid Oxide Fuel Cells

MRS Proceedings ◽

10.1557/opl.2014.330 ◽

2014 ◽

Vol 1644 ◽

Cited By ~ 1

Author(s):

Ryan Eriksen ◽

Srikanth Gopalan ◽

Sanjay Sampath ◽

Yikai Chen

Keyword(s):

Stainless Steel ◽

Fuel Cells ◽

Solid Oxide Fuel Cells ◽

High Temperatures ◽

Active Sites ◽

Protective Coatings ◽

Cost Effective ◽

Solid Oxide ◽

Oxide Fuel ◽

In Series

ABSTRACTOne of the major barriers to the adoption of solid oxide fuel cells (SOFCs) is the short lifetime of the fuel cell stacks. A stack consists of a number of cells in series separated by an interconnect. Due to the high temperatures necessary for SOFCs, typical commercial interconnects are ceramic. Great attention has been paid to decreasing the operating temperature of SOFCs in order to extend the life and decrease the cost of the stack. As operating temperatures decrease below 1000°C, alternative interconnect materials become viable. Stainless steel interconnects are more cost effective than ceramic interconnects but the high temperatures and the oxidizing environment of the cathode leads to the formation of a chromium oxide scale that increases the stack resistance. Chromium from the stainless steel can also enter the vapor phase and redeposit on the cathode thereby blocking the electrochemically active sites. One method to neutralize these effects is to coat the metallic interconnect in a ceramic such as La.8Sr.2MnO3 (LSM). The coating acts as a diffusion barrier both against chromium diffusing into the cathode and oxygen diffusing into the interconnect. In this study LSM has been deposited using plasma spray and tested in a dual atmosphere setup using impedance spectroscopy to analyze the performance of the coatings at various temperatures. The area specific resistance and chemical composition of the scale was examined in order to determine the affect of the LSM coating.

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Evaluation of Porous Ni-YSZ Cermets With Ni Content of 0–30 Vol. % as Insulating Substrates for Segmented-in-Series Tubular Solid Oxide Fuel Cells

Journal of Fuel Cell Science and Technology ◽

10.1115/1.4005607 ◽

2012 ◽

Vol 9 (2) ◽

Cited By ~ 2

Author(s):

Zhenwei Wang ◽

Masashi Mori ◽

Takanori Itoh

Keyword(s):

Thermal Properties ◽

Fuel Cells ◽

Solid Oxide Fuel Cells ◽

Open Circuit ◽

Solid Oxide ◽

Oxide Fuel ◽

Ni Content ◽

Isothermal Expansion ◽

In Series ◽

Oxide Ions

Nickel was added to a substrate composed of porous Y2O3-stabilized ZrO2 (YSZ) in order to minimize anode damage during redox cycling in segmented-in-series tubular solid oxide fuel cells (SOFCs) with YSZ electrolytes. In this study, the electrical insulating and thermal properties of these materials were evaluated for their suitability as substrates in the tubular SOFCs. When the Ni content was ≤20 vol. %, the porous cermets showed an electrical resistance of ≤67 Ω cm at 900 °C, indicating that the theoretical open circuit voltage for the tubular SOFCs could be achieved. However, the cermet with 20 vol. % Ni was destroyed during the first heating cycle in air because of large isothermal expansion. However, no obvious cracks were observed for cermets with ≤10 vol. % Ni. From the viewpoint of thermogravimetric measurement, this suggests that there are two redox mechanisms for Ni particles in the substrate. They were reduced/oxidized by both the gases and the oxide-ions passing through the YSZ framework. Based on the insulating and thermal properties of the substrate, the optimal composition was found to be approximately 10 vol. % Ni.

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