THE EFFECT OF THE MEMBRANE THICKNESS ON THE PERFORMANCE OF DIRECT METHANOL FUEL CELL FACTORIAL DESIGN

The direct methanol fuel cell (DMFC) is one of the most promising technologies to achieve high power density at room temperature. Many studies have been conducted to improve its performance by optimizing the operating conditions. The purpose of this work is to investigate the effects of membrane thickness under various pertinent operating conditions on the performance of the DMFC using the two-level factorial design method. The operating conditions include methanol concentration, temperature, cathode flow rate, and backpressure. Two models have been developed for the maximum power density of the DMFC using factorial design. The first model is a function of membrane thickness, temperature, cathode flow rate, and backpressure, while the second model is a function of membrane thickness and methanol concentration. The effects of membrane thickness with the other operating conditions are analyzed from the parameters of the developed models. It has been shown that increasing the membrane thickness decreases the maximum obtained power density. Increasing the membrane thickness along with methanol concentration or backpressure increases the obtained power density. The negative effect of membrane thickness increases with the rise of temperature or the lowering of the cathode flow rate. Using the factorial design, two other models are developed for the open circuit voltage (OCV) of the DMFC. The effect of the membrane thickness is always positive on the OCV.