Investigation of Elastomer Graphite Composite Material for Proton Exchange Membrane Fuel Cell Bipolar Plate

Author(s):  
Elaine Petrach ◽  
Ismat Abu-Isa ◽  
Xia Wang

The bipolar plate is an important and integral part of the proton exchange membrane (PEM) fuel cell and PEM fuel cell stacks. Currently bipolar plates represent more than 80% by weight and 40% by cost of the fuel cell stack. Traditional materials used for bipolar plates are primarily graphite and metal. Search for alternative materials to improve weight and cost considerations is needed. This paper discusses the results of an investigation of two elastomeric materials being developed for bipolar plate applications. Perceived advantages of the use of elastomers for this application include improved sealability without additional gasket material, reduction in the contact resistance between individual cells, improved formability, and weight reduction. The first elastomer investigated is a two component liquid silicone rubber, and the second is a polyolefin thermoplastic elastomer. These polymer matrix materials are made electrically conductive by the addition of conductive fillers including thermal graphite fibers (Cytec DKD & CKD), high surface area conductive carbon black nanoparticles (Cabot Black Pearls 2000), and graphite flakes (Asbury 4012). Electrical conductivity, processability, and elastic behavior measurements of the composites have been conducted. Some of silicone-graphite fiber composites material exhibit conductivity values comparable to those of the traditional graphite plate materials. Elasticity of all composites is maintained even at high filler concentrations.

2004 ◽  
Vol 19 (6) ◽  
pp. 1723-1729 ◽  
Author(s):  
Neil Aukland ◽  
Abdellah Boudina ◽  
David S. Eddy ◽  
Joseph V. Mantese ◽  
Margarita P. Thompson ◽  
...  

During the operation of proton exchange membrane (PEM) fuel cells, a high-resistance oxide is often formed on the cathode surface of base metal bipolar plates. Over time, this corrosion mechanism leads to a drop in fuel cell efficiency and potentially to complete failure. To address this problem, we have developed alloys capable of forming oxides that are both conductive and chemically stable under PEM fuel cell operating conditions. Five alloys of titanium with tantalum or niobium were investigated. The oxides were formed on the alloys by cyclic voltammetry in solutions mimicking the cathode- and anode-side environment of a PEM fuel cell. The oxides of all tested alloys had lower surface resistance than the oxide of pure titanium. We also investigated the chemical durability of Ti–Nb and Ti–Ta alloys in more concentrated solutions beyond those typically found in PEM fuel cells. The oxide films formed on Ti–Nb and Ti–Ta alloys remained conductive and chemically stable in these concentrated solutions. The stability of the oxide films was evaluated; Ti alloys having 3% Ta and Nb were identified as potential candidates for bipolar plate materials.


Author(s):  
Linfa Peng ◽  
Diankai Qiu ◽  
Peiyun Yi ◽  
Xinmin Lai

Contact pressure distribution between bipolar plate (BPP) and gas diffusion layer (GDL) has significant impact on performance and life time of proton exchange membrane (PEM) fuel cell. Most current studies for contact pressure prediction are based on finite-element analysis (FEA), requiring huge computation for the whole fuel cell assembly. Comparatively speaking, the more generalized and well-developed analytical methods are deficient in this field. The objective of this study is to propose a full-scale continuous equivalent model to predict GDL contact pressure effectively in the PEM fuel cell. Using the model, the nonuniform pressure distribution resulted from dimensional errors of metallic BPP and GDL could be obtained. First, a parameterized theoretical model of BPP/GDL assembly is established based on equivalent stiffness analysis of components, and definition methods of dimensional errors are proposed according to actual measurements and Monte Carlo simulation (MCS). Then, experiments are carried out to obtain the actual GDL contact pressure and the model results show good agreement with experimental results. At last, effects of dimensional errors are investigated. Acceptable assembly pressure for a given fuel cell is suggested based on the model. This model is helpful to understand the effect of the dimensional errors, and it also could be adopted to guide the manufacturing of BPP, GDL, and the assembling of PEM fuel cell.


2011 ◽  
Vol 228-229 ◽  
pp. 1029-1034
Author(s):  
Jian Lan ◽  
Chen Ni ◽  
Lin Hua

As a key component of proton exchange membrane fuel cell (PEMFC), the bipolar plate’s performance will directly affect the power output and battery life of the fuel cell. The conventional metallic bipolar plate is prone to warp, and has large flatness error with residual stress induced by forming process. This will result in contacting incompletely with membrane electrode assemblies (MEA) and lower fuel cell efficiency. A cylindrical structure of the PEMFC metallic polar plate is proposed to improve its stiffness and to reduce assembling error of the fuel cell. The polar plate features, which were originally designed on a flat surface, are projected onto the cylindrical surface with a certain curvature. Two cylindrical polar plates are welded together to become a bipolar plate. The finite element method is applied to compare the stiffness of the conventional and cylindrical polar & bipolar plates. The cylindrical bipolar plate has better stiffness and anti-warping than the conventional bipolar plate. The feasibility of the cylindrical structure is verified by experiment and provides a new idea for the improvement of the bipolar plate and fuel cell stack.


2012 ◽  
Vol 445 ◽  
pp. 108-113 ◽  
Author(s):  
H.J. Kwon ◽  
Y.P. Jeon ◽  
Chung Gil Kang

A Proton Exchange Membrane Fuel Cell (PEMFC) is a type of fuel cell being developed for automotive applications as well as for stationary fuel cell applications and portable fuel cell applications. Its performance such as power density can be improved by the use of the bipolar plate with a new lightweight material which is one of core components making up PEMFC stack. Aluminum alloy has good mechanical properties not only in terms of density, electrical resistivity and thermal conductivity, but also in terms of corrosion resistant compared with stainless steel and graphite composites bipolar plate. Furthermore, the use of aluminum for a bipolar plate reduces simultaneously the cost and weight of it, and it contributes to the ease of machining. For these reason, an aluminum alloy is selected in this study. This study presents the feasibility of the simulation for the development of aluminum bipolar plates that consists of multi array micro channels. The analytical solutions obtained by the simulation are validated by the comparison with the experimental results. From the results, it is ensured that the stamping processes for the bipolar plate could be predicted and designed by the results of the by FE-Simulation.


2013 ◽  
Vol 10 (4) ◽  
Author(s):  
Szu-Hua Wang ◽  
Wai-Bun Lui ◽  
Jinchyau Peng ◽  
Jin-Sheng Zhang

In this current study, we are attempting to build up a light weight and corrosion resistant bipolar plate for the proton exchange membrane fuel cell. A titanium bipolar plate substrate has been chosen as the base metal due to its low cost, simplicity to manufacture into stampable bipolar plates, and its light weight. Our goal is to obtain a smaller and lighter weight single fuel cell is to sinter titanium with a corrosion resistant material. Iridium oxide (IrO2) was investigated. The cell performance of the iridium oxide-sintered bipolar plates is close to and even better than the proton exchange membrane fuel cells, with graphite and pure titanium bipolar plates at low operating temperature with low and high membrane humidifier temperatures, respectively. Iridium oxide-sintered titanium bipolar plates can be employed to produce fuel cells with light weight and low sintering cost, ideal for portable applications.


Author(s):  
Diankai Qiu ◽  
Peiyun Yi ◽  
Linfa Peng ◽  
Xinmin Lai

Thin metallic bipolar plates (BPPs) fabricated by stamping technology are regarded as promising alternatives to traditional graphite BPPs in proton exchange membrane (PEM) fuel cell. However, during the stamping process, dimensional error in terms of the variation in channel height is inevitable, which results in performance loss for PEM fuel cell stack. The objective of this study is to investigate the effect of dimensional error on gas diffusion layer (GDL) pressure characteristics in the multicell stacks. At first, parameterized finite element (FE) model of metallic BPP/GDL assembly is established, and the height of channels is considered as varying parameters of linear distribution according to measurements of actual BPPs. Evaluation methods of GDL contact pressure are developed by considering the pressure distribution in the in-plane and through-plane directions. Then, simulation of the assembly process for a series of multicell stacks is performed to explore the relation between dimensional error and contact pressure based on the evaluation methods. Influences of channel number, cell number, and clamping force on the constitutive relation are discussed. At last, experiments are conducted and pressure sensitive films are used to obtain the actual GDL contact pressure. The numerical results show the same trend as experimental results. This study illustrates that contact pressure of each cell layer is in severely uneven distribution for the in-plane direction, and pressure change is unavoidable for the through-plane direction in the multicell stack, especially for the first several cells close to the endplate. The methodology developed is beneficial to the understanding of the dimensional error effect, and it can also be applied to guide the assembling of PEM fuel cell stack.


Sign in / Sign up

Export Citation Format

Share Document