Hindawi Publishing Corporation Journal of Energy Volume 2013, Article ID 571389, 11 pages http://dx.doi.org/10.1155/2013/571389 Research Article Influences of Contact Pressure on the Performances of Polymer Electrolyte Fuel Cells Prakash C. Ghosh Department Energy Science and Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India Correspondence should be addressed to Prakash C. Ghosh; pcghosh@iitb.ac.in Received 3 February 2013; Revised 13 May 2013; Accepted 18 May 2013 Academic Editor: Ching Yuan Chang Copyright © 2013 Prakash C. Ghosh. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Fuel cells face major challenges in sustaining the laboratory-scale performance during the scale up. Te contact resistance mainly arises from the dimensional mismatch between gasket and gas difusion layer during scale up, which may cause diminution in performance. In the present work, experiment as well as modelling is carried out for diferent combinations of clamping force and gasket thickness. Te polarisation behaviours of PEFCs confgured under diferent clamping torques and gasket thicknesses are analysed. Te combination of 0.3 mm gasket and 0.3 mm GDL under 3 Nm and 5 Nm clamping forces ofers 480 mΩ cm 2 and 148 mΩ cm 2 contact resistances, respectively. Te confgurations under 3 Nm and 5 Nm clamping torques with 0.2 mm thick gasket ofer contact resistances as low as 23 mΩ cm 2 and 11 mΩ cm 2 , respectively. Te polarisation behaviour obtained from the experiment of such confgurations is found to be in good agreement with the modelling results. 1. Introduction Fuel cells show great promises in the feld of portable, transport and stationary applications [1–3]. Tey show excel- lent current voltage characteristics in laboratory-scale cell. However, researchers encounter challenges during scale up due to the heterogeneous local performances inside the fuel cells [4–6]. Te local performance is infuenced by the oper- ating conditions such as humidity, temperature, and reactant pressure [7–9]. Assembly parameters such as clamping force and gasket thickness infuence the local and overall perfor- mances. Te contact resistance that mainly arises from the dimensional mismatch between the gasket and gas difusion layer (GDL) plays a signifcant role in overall performance of the polymer electrolyte fuel cell. Among diferent components, mainly matching in the thicknesses of the gasket and the GDL is important to achieve best performance in the fuel cells. Mismatch may lead to the following problems as illustrated in Figure 1. (i) Tinner gasket may lead to sealing problem causing safety issue. In addition to that, the cell will be facing mass transport-related losses ( Figure 1(b)). (ii) On the other hand, thicker gasket may result in poor contact between the bipolar plate (BPP) and the GDL, causing a rise in the contact resistance in the cell which will be refected on the ohmic region of the current voltage characteristics (Figure 1(c)). Hence, it is important to achieve optimum matching between the gasket and the GDL used in polymer electrolyte fuel cells. During the last decade, researchers focused on estimating the contact resistance, the polymer electrolyte fuel cells (PEFCs) [11] as well as solid oxide fuel cells (SOFCs) [12, 13]. Mishra et al. [14] presented a generalized fractal asperity-based model to predict the contact resistances as a function of con- tact pressure, material properties, and surface morphology at the interface. Nitta et al. [15] developed a 3D model to analyse the efect of compression pressure on fuel cell, and Liu et al. [16] studied the contact pressure distribution as a function of assembly parameter using response surface methodology (RSM). Su et al. [17] and Lee et al. [18] simulated the contact pressure distribution on the membrane electrode assembly (MEA) of the fuel cell for various assembly pressures. Chang et al. [19] studied the long-term efects of the clamping pressure on the performance of the PEFCs. Zhou et al. [20] investigated the efect of clamping force on the interfacial contact resistance and the porosity of the gas difusion layer (GDL) in a PEFC. Barber et al. [21] studied the clamping force and the interfacial morphology on interfacial contact