Carbon materials in composite bipolar plates for polymer electrolyte membrane fuel cells: A review of the main challenges to improve electrical performance

This review describes some recent developments in the area of flow field plates (FFPs) for proton exchange membrane fuel cells (PEMFCs). The function, parameters and design of FFPs in PEM fuel cells are outlined and considered in light of their performance. FFP materials and manufacturing methods are discussed and current in situ and ex situ characterisation techniques are described.

Polymer Electrolyte Membrane Fuel Cell (PEMFC) Flow Field Plate: Design, Materials and Characterisation

Effect of carbon fillers on properties of polymer composite bipolar plates of fuel cells

A Unitised Regenerative Fuel Cell (URFC) is a single cell that can function both as a fuel cell and electrolyser URFCs have mass and volume savings compared to conventional hydrogen systems employing a separate electrolyser and fuel cell Hence they have potential applications in electrical energy storage systems for a wide range of terrestrial and space applications This paper reviews the current state of art of this promising technology and identifies the main technical challenges to overcome to make the URFC system more technologically and economically viable The review reveals that the oxygen-side catalyst layer in a URFC is typically more challenging to design and construct, since a bifunctional catalyst layer and gas diffusion layer (GDL) must be made that functions equally well in electrolyser and fuel cell modes The prime goal in URFC development is to obtain a roundtrip energy efficiency very close that of a system with a separate electrolyser and fuel cell It is important to develop light weight, long-lived cells resistant to corrosion or other degradation, and retention of structural integrity and strength after repeated cycling and mode switching There is still a lack of practical designs and operating experience for URFC stacks scaled up to multi-cell stacks with supply power in the kW range In addition, development of URFC stacks able to deliver hydrogen at elevated pressure up to 20 bar in E-mode is essential So that hydrogen can be stored directly as compressed gas or in metal hydride cylinder to reduce the cost of external compressor and parasitic power in standalone power supply systems If these challenges can be overcome, URFC based on proton exchange membrane (PEM) technology has potential for reducing the cost of overall hydrogen fuel cell system and can offer clean, reliable and onsite hydrogen and power generation

PEM unitised reversible/regenerative hydrogen fuel cell systems: State of the art and technical challenges

Carbon based composites are extensively used in applications such as in polymer composite bipolar plates. This study was conducted to investigate the potential of both the use of milled carbon fibre as a conductive filler in a composite and the adaption of the General Effective Media (GEM) model to predict the electrical conductivity of the polymer composite produced. Polymer composites with various loading concentrations of the conductive filler with epoxy (EP) resin were developed using the compression moulding technique. Incorporating carbon nano tube (CNT) and carbon black (CB) as secondary fillers on carbon fibre (CF) reinforces epoxy composites aided in increasing the electrical conductivity of the composites. The addition of small amounts of CNT and CB as secondary fillers in hybrid systems increased the through-plane conductivity to 40.3 S/cm and 19.9 S/cm, respectively. The high aspect ratio and small size of the CNT filled the gaps between CF as primary filler so that there was a more conductive path. These phenomena increased the electrical conductivity of the CNT/CF/EP composites to a level higher than that of the CB/CF/EP composites. The flexural strength of CF/EP also improved from 64.37 MPa to 80 MPa and 70 MPa by adding CNT and CB, respectively. The dispersion and conductive paths mechanism were also investigated using scanning electron microscopy (SEM).

The effect of milled carbon fibre filler on electrical conductivity in highly conductive polymer composites

Bipolar plate made of carbon fiber epoxy composite for polymer electrolyte membrane fuel cells

It is now well known that the crude oil supply will not last forever and the world is facing another energy crisis. In other words, it is about time to invent or discover new energy resources that can last for centuries, if not indefinitely. Many expect that 'hydrogen era' will begin in the 2020's and that fuel cells will play an important role. It is also predictable that the biggest market for hydrogen fuel cells will be the auto industry. As of now, the costs of the fuel cell vehicles or the individual parts are far from being realistic from a mass production viewpoint. The answers to resolve many technical and other issues are being sought by fuel cell makers and auto manufacturers. Among the major auto makers which are trying to reduce the cost and enhance manufacturability of fuel cell vehicles (FCV), Hyundai-Kia Motors has the largest fuel cell research center in Korea. We have developed several different types of FCVs since its first launch of Santa Fe FCV in 2000, and are seeing the promising outcome. The second generation FCVs made in 2004 and 2005 shows many improved features and performance data compared to the 2000 version. In this paper, we present the basic principles of fuel cells and the history of FCVs. In addition, the status of FCV development at Hyundai-Kia Motors will be introduced. Verification programs sponsored by Korean and American governments are also presented to show how actively we are collaborating with other fuel cell-related companies in order to make FCVs commercially available as soon as possible.

Tae Won Lim

Papers

Bipolar plate made of carbon fiber epoxy composite for polymer electrolyte membrane fuel cells

Past, Present and Future of the Fuel Cell Vehicle Development at Hyundai-Kia Motors