Losses resulting from in-plane electricity conduction in tubular solid oxide fuel cells

A mathematical model has been developed that describes the potential distribution along the length of a tubular fuel cell. Insight into this distribution is essential because, as opposed to the planar fuel cell, the electricity has to be transported over a relatively long distance before connecting to the next cell. The model is based on an electrical network representation of the fuel cell and consists of resistors parallel and perpendicular to the plane cross section of the cell. The first result from the electrochemical process as would take place in any fuel cell. The second constitute losses resulting from electricity transport along the electrodes. The model leads to a differential equation, which is solved numerically. The modelling results show that in order to achieve high outputs there is a requirement to reduce electrolyte wall thickness and to limit the active length due to in-plane losses