Consequently, electrochemical power sources are be-coming increasingly important as a means to guarantee this reliable power supply.. In fact, most nonportable applications such as stati
Trang 1Military: Batteries and Fuel Cells
C Cremers, J Tu¨ bke, and M Krausa, Fraunhofer-Institute for Chemical Technology, Pfinztal, Germany
& 2009 Elsevier B.V All rights reserved.
Introduction
In order to ensure their own leadership capability,
sustainability, supportability, mobility, or survivability,
modern armed forces are becoming increasingly
depen-dent upon having a reliable supply of electrical energy
Consequently, electrochemical power sources are
be-coming increasingly important as a means to guarantee
this reliable power supply As this concerns quite a broad
field of applications, the potential solutions using
elec-trochemical power sources are also quite different This
article focuses on one specific sector, that of portable
applications In fact, most nonportable applications such
as stationary power supply for military bases, in the form
of power generation or backup power, or mobile power
supply for traction of military land, sea, or air vehicles
are not very different from corresponding civil
appli-cations, so the reader should have a first insight into these
topics by reading chapters related to civil applications
Still the portable applications discussed here cover a
broad range of energy and power demands starting from
a few watts over long periods of time for remote sensors
to about 1 kW for portable rechargers for batteries used
by entire squads Also, the duration over which the
electrical energy needs to be supplied varies and,
therefore, the required energy content or density of the
electrochemical power source also varies Finally, in
many applications, the power demands vary with time so
that no single type of power source is fully suitable but
hybrid solutions combining different types of power
sources will be required Such hybrid solutions may end
up in energy networks worn by the soldier, allowing
harvesting of energy from any power source that might
be available and to dedicate power to whichever
appli-ance is in need of it
Batteries
General Considerations
Batteries are still the most important source of portable
electric power in military applications and these are
ex-pected to continue to play an important role in future
power supply scenarios
Today, quite a broad range of batteries are used in the
military sector as can be seen from the fact that the
generic standard for batteries in the United Kingdom
DEF STAN 61-21 currently has about 50 supplements
describing the different batteries used in the UK army In
part, this is due to the fact that each appliance such as radio, night sight, and global positioning system (GPS) device has its own battery However, certain trends can be found
One important trend is an increasing use of lithium-based technology for both primary and secondary bat-teries For example, the most used type of primary battery
in the US Army today, the BA-5590, is a lithium–sulfur dioxide battery Alternative primary battery technologies comprise lithium–manganese dioxide and lithium–thionyl chloride In the field of rechargeable batteries, nickel– metal hydride batteries are currently being replaced by lithium-ion batteries
Another important trend is a greater use of secondary batteries This will become necessary as the increasing demand for electrical energy causes severe logistic problems if only primary batteries are used to fulfill the demand Further on, rechargeable batteries offer a higher flexibility as part of hybrid systems or energy networks,
as will be shown later
An exception to this trend toward secondary batteries are metal–air batteries, which are increasingly used for special applications demanding a long-term supply of energy at lower power densities where they compete with small fuel cells
As with all military equipment, batteries for military applications need to be able to operate under quite harsh conditions So usually temperature endurance from 40
to þ 70 1C, high humidity resistance, and resistance against shock and vibrations are required A further constraint is the required ability to operate at high alti-tudes up to at least 2500 m For most primary and sec-ondary batteries, this is not an issue but all air-consuming types of power sources such as fuel cells or air–metal batteries are likely to suffer from the reduced oxygen partial pressure at these conditions
Common Military Primary Batteries For the most part, the batteries used during combat op-erations are primary batteries Although primary bat-teries offer the highest capacity, the problem is that they are often replaced after each mission, even though many
of those discarded batteries would still have had sufficient capacity This results in high battery usage costs, which could be lowered by a built-in state of charge indicator or the usage of secondary (rechargeable) batteries
There are about 13 different types of lithium batteries, which are the most used type of military primary
13