RESEARCH

With ability to deliver more power per unit weight as well as volume, cylindrical/tubular PEM fuel cells seem to have outnumbered the conventional cuboid form of their counterparts in terms of performance. Such structures, therefore, can be thought as a better solution to small to medium power applications viz. drone, space applications etc. Furthermore, as water, in vapor form, gets produced on the cathode side which is exposed to the environment, it becomes relatively simple in management leading to lesser mass transfer losses.

Cylindrical PEM fuel cells are inspired from solid oxide fuel cells in terms of design, however, lack both in terms of integrity as well as scalability. Our group is constantly involved in development of such structures as well as understanding their optimized functioning. 

 Energy requirement in standalone systems viz. mobile towers, remote locations, military applications etc. has been growing quite extensively. Providing sufficient and continuous energy sometimes becomes burdensome given the complexity of location as well as time of demand. Fuel cells, in such situations and times can come really handy when coupled with primary energy source such as PV modules. However, these electrochemical devices work only when supplied with necessary gases i.e. fuel and oxidant. The very idea of URFCs, is therefore, to utilize surplus energy available from the primary source and the structure of fuel cell to generate the said gases. URFCs, therefore, work in both fuel cell as well as electrolysis mode thereby generating power as per demand as well as converting the available energy into the chemical energy. URFCs are said to understand the dynamics of intermittency of renewable source and make the system compatible with the grid.

URFC is relatively a new technology and is more complex as it houses both fuel cell as well electrolysis within itself. It is currently being explored for various of its aspects including operational parameters, design modifications as well as durability issues. The stability of URFC is highly affected by the materials chosen due to extreme acidic conditions further complicated by higher operating potentials in electrolysis mode.

The overall performance of any fuel cell is highly dependant on many factors including material selection and their mechanical and/electrical properties. It, therefore, becomes extremely important to keep all the cell components well connected with each other such that the flow of electrons across the interface of different components is offered with least resistance. Such resistance adds almost upto 55% of the total ohmic resistance if not addressed well. 

We are currently looking into the engineering issues of scaled up cells as with increase in the electrode area the quality of contact pressure and its distribution is decreased. Furthermore, optimization of gas diffusion layer (GDL) in terms of mechanical properties as well as its thickness, gasket material and thickness etc. is often not paid enough attention in scaled up cells which affect the electrical conductivity of the system badly.