Page 173 - Battery Reference Book

Lithium-lead bismuthate primary cells 9/13

Table 9.9 Characteristics of lithium-manganese dioxide cells
Open Volts Discharge Gravimetric Volumetric Gravimetric
circuit under voltage energy energy power
volts load proJile density density density
(VI (Wmg-') (W h/dm3) (W kg-' )

3.0-3.6 2.7-3.0 Relatively 150-350 450-750
flat

Volumetric Storage Operation Self Calendar Types
power temperature temperature discharge life available
density ("C) ("C) rate
(W ~m-~)
~~
- 40 -20 to 70 -20 to 70 1% pfa Up to 6y at 20°C Coin, cylindrical,
(crimp seal) (crimp seal) (crimp seal) flat, prismatic,
-40 to 85 -40 to 85 0.5% (85% capacity available
(laser seal) (laser seal) ?la retained)
(laser seal)

dioxide. (Corresponding Whkg values are 300, 100, decreasing gradually to 0.9 V over a further 150 hours,
100 and 300.) 'The annual self-discharge rate at 20°C i.e., 300 hours discharge to 0.9V.
is 2-3%. Battery packs containing groups of cells The system has exceptional storage characteristics.
connected in seriedparallel are available for specific Cells can be exposed to a wide range of conditions
applications. in which they are exposed to forced current in both
This cell exhibits two voltage plateaux on discharge the charge and discharge directions without incident.
at higher temperatures (70°C). Discharge starts off Over charge can cause cell ruptures as does exposure
at about 1.6V reducing to 1.3V towards the end of to temperatures above 180°C. Mechanical abuse does
discharge. The cell can be operated at temperatures not cause fires or explosions. In general, provided the
between -55 and 150°C. Cells which had been stored guidelines are adhered to, no hazards are presented to
for two years at 21°C gave 93.5% of their original the user.
capacity. Self-discharge rates are acceptably low. Volt-
age delay effects do not occur. 9.7 Lithium-silver chromate primary
The cells have resilience to electrical and
mechanical abuse. The use of safety shunt diodes batteries
across each cell limits voltage reversal to within safety SAFT supply a range of these 3.1 V cells with capaci-
limits. ties in the range 130-3100mAh (cylindrical cells) and
Cylindrical IL .5 V batteries are available in 3.6 Ah 2090-2450mAh (rectangular cells), see Part 6.
(type LCOI), 1.6Ah (type LC02) and 0.5Ah (type The special features of these cells are high reliabil-
LC07). Applications of this type of cell include oil ity (better than 0.7 x lo-'), indication of end of life
well logging equipment, microprocessors, telephone by a second plateau voltage, a discharge capability
systems, public address systems, high-temperature heat up to 100pA, and low internal impedance. Applica-
counters, CMOS memory protection, telex systems, tions of lithium-silver chromate cells include cardiac
high-temperature devices and specialized industrial stimulators and other human implantable devices, high
and military applications. Details of performance are reliability memory protection for inertial navigation
given in Table 9.10. systems, and RAM back-up power sources.
On-load voltage is nomnally 1.5 but this depends
on rate of discharge and temperature. This is a high
energy density system (300 W kg-' , 630 W h dm-3) 9.8 Lithium-lead bismuthate primary
which leads to high capacity cells, e.g., the AA size cells
has a capacity of 3.7 Ah. The system is ideally suited
to low load applications when lives in excess of 10 SAFT supply this type of cell. It has a nominal
years have been obtained. An AA size 3.7Ah cell voltage of 1.5 V, exhibits a high energy density
discharged at I, mA cmp2 (lithium electrode area) at (400-500WNdm3, 90-150Whkg), has long life
20°C to an end-point voltage of 0.9V gave a cell expectancy and is interchangeable with normal IEC
voltage of about 1.4V for about 150 hours discharge, button cells with a nominal voltege of I .5 V. The cells