Finding the optimal flow pattern in bipolar plates of a proton exchange membrane is a crucial step for enhancing the performance of the device. This design plays a critical role in fluid mass transport through microporous layers, charge transfer through conductive media, management of the liquid water produced in microchannels, and microporous layers and heat management in fuel cells. This article investigates different types of common flow patterns in bipolar plates while considering a uniform pressure and velocity distribution as well as a uniform distribution of reactants through all the surfaces of the catalyst layer as the design criteria so that there would be a consistent electron production by the catalyst layer. Then, by identifying the important parameters in achieving the best performance of a fuel cell, a microfluidic flow pattern is inspired from the lungs in the human body, and an innovative bipolar plate is suggested, which was not proposed before. Afterwards, numerical simulations were carried out using computational fluid dynamics methods, and the mentioned bipolar plate called lung-shaped bipolar plate was modeled. Simulations in this research showed that the lung-shaped microfluidic flow pattern is an appropriate flow pattern to gain maximum power and energy density. In other words, the best polarization curve and power density curve are obtained by using the lung-shaped bipolar plate in a proton exchange membrane fuel cell compared with previously suggested patterns. Copyright (c) 2017 John Wiley & Sons, Ltd.