Contents lists available at ScienceDirect Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser A comprehensive study of the effect of bipolar plate (BP) geometry design on the performance of proton exchange membrane (PEM) fuel cells Tabbi Wilberforce a,* , Zaki El Hassan a , Emmanuel Ogungbemi a , O. Ijaodola a , F.N. Khatib a , A. Durrant a , J. Thompson a , A. Baroutaji b , A.G. Olabi c,d a Institute of Engineering and Energy Technologies, University of the West of Scotland, Paisley, PA1 2BE, UK b School of Engineering, Faculty of Science and Engineering, University of Wolverhampton, UK c School of Engineering and Applied Science, Aston University, Aston Triangle, Birmingham, B4 7ET, UK d Dept. of Sustainable and Renewable Energy Engineering, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates ARTICLE INFO Keywords: Bipolar plate Current density Mass transport Channel length Proton exchange membrane fuel cell (PEMFC) Membrane ABSTRACT Fuel cell efficiency is determined by many factors, including operational parameters such as electrochemical kinetics, cell operating temperature, mass transport, flow rates and other physical components in the cell stack like the membrane electrode assembly (MEA) as well as the bipolar plate (BP). The BP accounts for almost 70% of the mass of the stack and 30% of the overall price of the cell stack on the fuel cell market. The bipolar plate geometry design serves as the medium of entry of the reactive gases into the fuel cell and also functions as a platform for easy dissemination of the reactive substance onto the active surface of the cell stack. Its crucial role in the stack determines water management for the PEM fuel cell, thermal and electrical conductivity, mass transport and current density distribution. This research therefore aims to make a critical assessment of existing bipolar plate geometry design with respect to the maximum functionality of fuel cell (advantages and dis- advantages of each design considered). The work thoroughly discusses some parameters that define an effective bipolar plate geometry design which is able to enhance the functionality of a cell stack. Furthermore, the work will serve as a guide to the fuel cell research community in the selection of a suitable geometry design for any fuel cell operating at varying conditions. 1. Introduction Most research work conducted in recent times is geared towards the usage of renewable energy due to the rapid depletion of fossil reserves, unstable prices of fossil commodities and the negative effect of fossil fuel on the environment [1]. Clean energy that is environmentally friendly is therefore the future of the energy generation industry. A good substitute for fossil fuel use, according to several pieces of re- search, is the fuel cell because it is one of the cleanest means of pro- ducing energy among the renewable energy generation mediums. The PEMFC is often preferred to other types, such as Alkaline fuel cells (AFCs), Solid oxide fuel cells (SOFCs) etc. This is because PEM fuel cells are highly reliable and have a quick start up time with good operating temperature range between 60 and 80 °C [2,3]. Again, they have a longer life span compared to the other type of fuel cells. Another im- portant factor that makes PEM fuel cells considered the best type is its high power density. These advantages of fuel cells are the reasons for the high demand of this technology especially in the automotive industry, portable as well as stationary applications [4]. In the last decades, the research community has carried out several experimental activities aimed at improving the overall functionality of PEMFCs. The main objectives for some of these researches were to increase the cur- rent and voltage being generated from the device with the least hy- drogen gas supplied. Arguably, there are several factors that determine the characteristic performance for any cell stack. Some of these factors are classified under operating conditions of the fuel cell, mass transport, water management, electrochemical kinetics of the fuel cell, clamping pressure and leakages of hydrogen gas. Overall efficiency for the stack is dependent on the performance of the single cells involved. This is not ideal situation for cells in practical operation. Each cell making up the stack receives a different flow rate of hydrogen at any given time and this is often due to the bipolar plate geometry for each cell. Poorly designed bipolar plates lead to uneven gas distribution through the fuel cell, localized hot spots in the electrolyte, unstable current density and complete destruction of the device caused by poor water management [5]. In situations where the gases are evenly distributed due to proper https://doi.org/10.1016/j.rser.2019.04.081 Received 28 September 2018; Received in revised form 29 April 2019; Accepted 29 April 2019 * Corresponding author. E-mail address: b00281710@studentmail.uws.ac.uk (T. Wilberforce). Renewable and Sustainable Energy Reviews 111 (2019) 236–260 1364-0321/ © 2019 Published by Elsevier Ltd. T