Homepage for Surface Embedded Metal Oxide Sensors (SEMOS)

Fuel Cell Fundamentals

A fuel cell is an electrochemical device. With high efficiency it can convert chemical energy directly into electrical energy without combustion and without moving parts, it is in fact the best known way to convert the chemical energy of fuel into electricity. A fuel cell basically consists of two electrodes and one electrolyte. Typically hydrogen is split into protons at the anode of the fuel cell, in that process two electrons are released. The electrolyte, which facilitates proton conduction, conducts the protons to the cathode side. At the cathode side the protons reacts with oxygen and forms pure water.
PEMFC

Fuel Cell Types:

Several different types of fuel cells exist. They are usually named according to the electrolyte material. The most commonly used types of fuel cells are listed below.

Types

Abbreviation

Electrolyte

Ion

Operating temperature [°C]

Low Temperature Proton Exchange Membrane Fuel Cell
LT-PEM
Polymer
H+
50-90
High Temperature Proton Exchange Membrane Fuel Cell
HT-PEM
Polymer
H+
140-180
Direct Methanol Fuel Cell
DMFC
Polymer
H+
70
Solid Oxide Fuel Cell
SOFC
Polymer
O2- 650-1000
Phosphoric Acid Fuel Cell
PAFC
Phosphoric acid
H+ 150-200
Molten Carbonate Fuel Cell
MCFC
Carbonate salts
CO3- 650
Alkali Fuel Cell
AFC
Potassium hydroxide in water
OH- 150-200



In this project the sensors are tested on a HT-PEM platform. The HT-PEM fuel cell used in this project is a commercially available Membrane Electrode Assembly (MEA) with a PBI-based membrane.

Why use Sensors in Fuel Cells?

In order to improve the durability and efficiency of fuel cells it is absolutely essential to have in situ knowledge of the state inside the fuel cell. A good way to achieve highly detailed information of the processes occurring in a fuel cell is the use simulation and modelling tools. In order to verify that the models are correct detailed experimental data is needed. In the SEMOS project in situ sensors are constructed capable of providing data suitable for validation of the simulation models. Furthermore, the sensors are generally expected to provide information that can remedy some of the failure mechanisms leading to reduced lifetime and efficiency of the fuel cell.

Motivation for SEMOS

Extracting in situ experimental data from a fuel cell is by no means trivial. The environment in a fuel cell is very harsh and the geometry of the components does not facilitate conventional sensors. In the SEMOS project new sensors are developed which can withstand the tough location in a fuel cell.