A Study on Property and Performance According to the Pore Structure of Metallic Porous Separator for Fuel Cell Vehicle

Abstract

In generally, Bipolar plate is vital component of PEM fuel cells, which supplies fuel and oxidant to reactive sites, removes reaction products, collects produced current and provides mechanical support for the cells in the stack. At the present, the bipolar plate for fuel cell vehicle is metallic separators formed of metallic materials such as stainless steel. The existing bipolar plate includes a land(contacting) portion directly bonded to the gas diffusion layer(GDL) and a channel portion that serves as a supply passage of reaction gases and an exhaust passage of water between land portions. In the typical separator, the land portion and the channel portion are disposed in a longitudinal direction and a flow field area in which the channel portion is formed both have a longitudinal structure. Also, the land portion and the channel portion are distinctly separated from each other.However, in the case of a typical separator, this non-uniformity causes a concentration difference between the area that the channel portion contacts and the area that the land portion contacts among the whole area of the MEA where the electrochemical reaction occurs and the performance of fuel cell is decreased.In this paper, a porous separator with various structures for a fuel cell, which causes the high diffusion of reactant gases was studied for increasing the performance of fuel cell. Also, we conducted an analysis of the properties(contact resistance, corrosion etc.), machinability(uniformity of thickness, change of hole structure etc.) and performance according to hole and pitch structure.In conclusions, the porous separator with optimum structure shows the performance above 200mA/cm 2 at 0.6V in comparision with the typical separator. It is considered to be minimize concentration differences between area in a gas diffusion layer and achieve uniform electrochemical reaction and electricity generation over the whole reaction are, by improving the structure of a flow field in which reactant gases flow.

Key findings

• ▸The non-uniformity of the land and channel portions in typical separators causes a concentration difference in the MEA, affecting fuel cell performance.
• ▸The study suggests that a uniform pore structure can improve the performance of metallic porous separators in fuel cell vehicles.
• ▸The research indicates that the pore structure of the separator has a significant impact on the overall performance of the fuel cell.

Keywords

Identifiers

DOI

10.1149/ma2016-02/38/2728

Journal

ECS Meeting Abstracts

Year

2016