Performance of 3D-Printed Fuel Cells and Stacks

Abstract

3D-printing, a.k.a. additive manufacturing (AM), has become a popular topic in the general public and in industry [1]. There is recent interest in using AM to fabricate fuel cell components because of AMs ability to build metal parts with complex geometries with relatively short lead times [2]. Fuel cell bipolar plates (BPPs) require complex internal passageways for coolant flow fields making them a good candidate for AM. By building one piece BPPs the number of parts, the number of seals and the complexity of assembly can be decreased. We present the performance characteristics of a 400W fuel cell system made with BPPs made of Ti-alloy (Ti-6Al-4V) and built by 3D-printing. The BPPs are made by direct metal laser sintering (DMLS) and are coated by Treadstone Inc. with Au-microdots and a TiO2layer to decrease contact resistance and protect against corrosion. Titanium alloy is examined because of its high strength-to-weight ratio which makes it an ideal material for aerospace applications. This work extends our previous work regarding the contact resistance of 3D-printed metal BPPs to include functional fuel cell stacks [3]. The performance characteristics of single cells and stacks will be discussed in the context of surface finish, flatness, feature tolerance, weight, cell-to-cell variability, scaling and contact resistance. Overall DMLS is an exciting new technique with great promise for future rapid prototyping of BPP designs and many other fuel cell components. However, greater advances in surface finish, feature thinness and flatness are needed before BPPs built by 3D-printing will compete with the traditional machined or formed BPPs.