A recent report on Fuel cell demand has
suggested that the global fuel cells market’s turnover was over USD 3.6 billion
in 2016 and also predicted, with a compound annual growth rate 10.5%, the
demand will reach to USD 6.54 billion by 2022. This high demand needs to be met
by utilizing the available resources with the help of highly developed Fuel
cell power systems. However developing these systems requires overcoming of
certain limitations like difficulty in monitoring, instrumentation & data
acquisition of system parameters as well as improving the reliability and
durability. This review paper strives to analyze various data acquisition &
diagnosis systems and suggest improvements that help to curb these limitations.
The modern-day Fuel cell system, on one hand, is expected to have high
resolution, isolation, and waveform acquisition capabilities while on another
hand should exhibit traits like prompt fault detection and efficient diagnosis.
Increase in global warming has made the
pollution norms stricter and has created an urgent need to ponder on efficient
use of non-pollutant energy sources. One of the promising green energy sources
is the hydrogen energy owing to its free green-house gases produced and high
The FC system is an electrochemical device,
which transcends the chemical energy of the fuel into electrical energy. There
are several types of FC according to the employed electrolyte type. Whatever may be the type of fuel cell, their
basic operation is always the same. For this paper, we will limit our
discussion to the widely used Proton Exchange Membrane Fuel Cell (PEMFC) due to
their ability to operate at low temperatures, short start-up time and high
Fuel Cell working
FC configuration consists of Anode, Cathode, and Electrolyte wherein the
electrolyte is packed in between the anode (negative electrode) and cathode
(positive electrode). The anode catalyst (mostly platinum powder) oxidizes the
hydrogen fuel transforming it into hydrogen ions and electrons. These electrons
pass through anode to cathode via an external circuit producing electricity.
The hydrogen ions produced pass through the electrolyte to the cathode, combine
with oxygen that is reduced at the cathode (Nickel as a catalyst) , thus
producing water. The fuel cells can be connected in series so that the net
voltage of the combination matches to the high amount of desired voltage. This combination
is called FC stack.
Fuel Cell Systems functioning
The FC system consists of four circuits, as
depicted in Fig. 2, namely such as air, hydrogen, humidification and the
electrical circuit. The Hydrogen valve controls gas H2 flow. The air filter
removes solid particles like dust, molds and bacteria while the motor
compressor increases the pressure by reducing air volume. The humidifier
increases the moisture in the compressed so that the air reaches the cathode at
operating condition. The fluid manifold, consisting of one input and several
outputs, distributes the gas uniformly to ensure the supply of fuel gas of each
cell of the stack. The cooling unit includes two electric fans. One of which is
placed beside the compressor and the humidifier for cooling, and the and
another fan makes sure that stack is at low temperatures under normal operating
conditions. The FC system is kept in proper operating mode by deploying
following Management systems:- (a) Air Management system (b) Water Management (c)
Fuel Management (d) Thermal Management.
Data Acquisition system (DAQs) is a
pre-processing unit wherein the physical parameters of a system, in the form of
waveform signals, are acquired, sampled, conditioned according to the
constraints and finally converted to digital signals before feeding it to the
signal processing and control unit.
The development of different diagnostic tools for FC systems
become a must in order to ensure safety, security, and availability during
faults. Consequently, these faults should be detected as early as possible.