Page 195 - Battery Reference Book

Performance characteristics of lithium anode thermal batteries 1313
Thermal electrochemical batteries have been manufac- 1. Electrical High- and low-energy matches and
tured since 1946 to meet the needs of applications squibs with wire bridges are available. Firing
requiring instant power, fast activation, short oper- energies of two of the units are shown in Table 13.1.
ating life, high energy density, high amperage and 2. Mechanical An M42G primer similar to that in
a shelf life claimed by various manufacturers to be a .38 calibre bullet, with a modified charge, has
between 12 and over 20 years. Battery voltages from been used extensively in thermal batteries. Spring
2.3 to 500V XI- available. Thermal batteries contain or explosive-driven firing pins are used to deliver
an electrochemical system that is inert until activated the 1800cmg of energy required for primer firing.
by application of heat. They may be stored on load A second method of mechanical initiation uses a
or open circuit. The cell electrolyte used is a mixture self-contained inertial starter which is activated by
of anhydrous salts which conduct current only when forces of 300-600g imposed on the battery.
molten. A heat source, which can be ignited either by
an electric match or a mechanical primer (percussion The corresponding parameters for calcium anode
cap), is an integral part of a thermal battery. When thermal batteries supplied by Eagle Picher are similar
the battery is ignited, this heat source develops snf- (see Table 13.2).
ficient heat energy to melt the electrolyte and thus
permit the battery to deliver a considerable amount
of electrical power. Activation times are rapid (as low Table 13.1 Firing energies of Catalyst Research Corporation
as 0.3-2.5 s). The batteries have an open-circuit volt- calcium anode thermal batteries
age of 2.3-3.0 Irkell. Voltage regulation is within 10%
of nominal undier constant resistive load. The battery No jre Alljre
operating range covers the interval 1-300 s. There
are two principal types of high-temperature thermally Match 0.25 A for 5 s 0.50 A for 50 ms
3.5 A for 20 ms
Igniter
1Afor5min
activated battery; those based on calcium anodes and
those based on lithium anodes. Within each of these
types there are many possible configurations available.
Table 13.2 Eagle Picher calcium anode thermal batteries
.I Performance characteristics of High-rate capacity 10 A for 60 s
calcium anode thermal batteries Low-rate capacity 250 mA for 300 s
Activation time 100ms to 3.5 s
Catalyst Resezrch Corporation have designed and Operating temperature -54 to +93"C
developed a higlh-efficiency electrochemical system for Storage temperature -54 to +74"c
use in high cunrent density applications. This 'Power Storage life Up to 10 years at storage
Cell' system has the flexibility for use in both short- temperature
and long-life battery requirements. Available power Vibration Withstand 300g all areas
output is approximately 2.5% greater than that of con- Shock Withstand 3000g longitudinal
ventional thermal battery systems. Performance data Acceleration Withstand 450g longitudinal
on this battery are given in Table 60.3.
Catalyst Research Corporation also supply fast-
activation therrnal batteries. Th.ese are to meet the
needs of applications requiring battery power to fire 13.2 Performance characteristics of
squibs, electric matches, dimple motors, explosive lithium anode thermal batteries
bolts, etc., after battery activation.
Table 60.2 presents size and performance for some Quite large thermal batteries of this type are being
typical units which have been supplied in the three produced; one lithium-iron sulphide battery produced
categories of fast-start batteries; high current pulse, by Mine Safety Appliances weighs 3.8 kg, consisting
medium life and high current. Catalyst Research Cor- of 30 series cells housed in a container 89mm in
poration also piroduce a high-voltage thermal battery diameter by 235 mm long. This battery shows smooth
designed to meet the need for high-voltage low-current discharges and freedom from electrical disturbance
power supplies. Typical specifications for such units for average current densities varying from 0.3 to
are shown in Table 60.4. 1.86A/cm3. To 80% of the peak voltage, durations
Calcium anode thermal batteries are capable of range from 3 to 21 min. It is also noteworthy that
operation at temperatures between -54 and +73T at the cell capacity is very constant at 275A minimum
accelerations up to 2500 lateral, under a shock of up over this range of discharge rates, although there are
to 200g and vibration of 30g and also at spin rates of indications of some reduction ai the highest current
400 rev/§. density. To compare the performance with typical
Activation of the battery by ignition or an internal results obtained for the Ca/LiCl-KCI, CaCr04Fe
heat source can be achieved by several methods: system for this capacity of lithium-iron sulphide cell,