The effect of rubber hardness on the channel depth of the metallic bipolar plates fabricated by rubber pad forming

Abstract

Polymer electrolyte fuel cells (PEMFC) are electrochemical devices, converting the chemical energy directly into electrical energy. PEMFC is an appropriate alternative to use as an energy supplier of electric motors. The bipolar plate is one of the most important components of PEMFC. It has a significant effect on the volume and cost of the fuel cell. Various materials have been used for the production of bipolar plates, however, the metallic type has attracted much attention owing to appropriate mechanical, electrical, and thermal properties [1]. It’s necessary to use an efficient and cost-effective method for manufacturing of metallic bipolar plates. Several methods have been used by researchers including stamping, hydroforming, and roll forming [2]. In the present study, the effect of the rubber hardness during rubber pad forming of metallic bipolar plate is investigated. A concave die with a serpentine flow field is used to fabricate the bipolar plate made of SS 316 with a thickness of 0.1 mm. The effect of rubber hardness on channels depth is investigated in the longitudinal, transverse, and diagonal directions. The result shows a direct relation between applied force and channels depth achieved in all directions. Also, maximum channels depth decrease by raising the hardness of rubber while a significant reduction in the hardness of rubber leads to inadequate pressure for the deformation of the sheet metal.