Page 177 - Battery Reference Book

Lithium-molybdenum disulphide secondary batteries 9/17
electrolyte (Li plus Li8P400.25Si13.75) has reached a Table 9.14 Characteristics of Catalyst Research Corporation
semi-commercial state. model 802/23 solid lithium-iodine pacemaker battery
.I 1 Lithiuim-iodine primary batteries Nominal size 23 x 45 x 13.5mm
Volume
11.2cm3
9.11.1 Pacemaker batteries Weight 30 E
Density 2.7 gkm3
Since 1972, the Catalyst Research Corporation (USA) Lithium area 17.1 cm2
has been the supplier of the lithium-iodine batter- Voltage 2.80 V under no load
ies intended initially for cardiac pacemakers and other Nominal capacity 2.3Ah
implantable devices. They supply 70% of pacemaker Energy 6.0 W h
batteries used in the world. They claim that the capa- Energy density 530Wh/dm3, 200Whlkg
<lo% in 10 years
Self-discharge
city of this battery is four times that of the Mal- Seal Heliarc welded with glass-metal
lory MU-I mercury-zinc pacemaker battery and that hermetic seals; less than 4.6 x
the lithium-iodine battery operates more efficiently at 1W8 maximum helium leak, by
body temperature than at room temperature. Since the helinm-backfill method
lithium-iodine reaction generates no gas, the cell can Insulation resistance > 10'' from pin to case
be hermetically sealed. A feature of this type of battery Storage temperature 40 or 50"C, brief excursions to
is its extremely high reliability. At the time of writ- 60°C
ing, Catalyst Research had supplied 150 000 batteries
for use in cardiac pacemakers without a single failure
or premature rundown. Catalyst Research Corporation 9.11.2 Non-medical lithium-iodine batteries
lithium-iodine batteries are marketed in the UK by
Mine Safety Appliances Ltd. Figure 56.26 gives performance characteristics of the
The lithium-iodine battery differs from other Catalyst Research Corporation S23P-1.5 cell. The
lithium batteries in the following respects: largest cell available in this range, the D27P-20,
with a capacity of 0.260Ah, would be useful for
1. Lithium-iodine batteries contain no liquid elec- long-life liquid crystal display applications or in ana-
trolyte. logue watches with stopping motors. It should be
2. Lithium-iodine batteries do not require a separator ideal for calculators where, at a 50pA drain, it
material to keep the anode from contacting the could deliver more than 5000 h of use over as much
cathode. as a 10-year period. Its performance is shown in
3. The total volume of the cell remains the same dur- Figure 56.27.
ing discharge; there is neither swelling nor shrink- Catalyst Research also supply 460mA h (type 2736)
ing of the cell during discharge. and 870 mA h (type 3740) batteries.
4. The cell is hermetically sealed with a metal-to- Lithium-iodine batteries offer energy densities on
metal fusiori weld and glass-to-metal seals. a volume basis of 1.5-2 times that of conventional
5. No gas is piioduced by the reactions and no gas is batteries and on a weight basis of up to three
given off by the cell. times that of conventional button cells such as the
zinc-mercuric oxide types. More important is the fact
A full specification of the Catalyst Research Cor- that these batteries offer 10 years of storage. rather
poration current pacemaker battery model 802/23 is than the 2-3 years expected of conventional batteries,
given in Table 9.14. The projected electrical per- which has considerable implications for user-designer
formance over an 18-20-year period is shown in applications; for example, the 10-year cakulator or
Figure 9.10.
digital watch becomes possible. These cells will accept
a recharge provided charging currents are restricted
to the same maximum as imposed on the discharge
current. This might be useful in solar cell, rechargeable
watch or calculator applications.

9.1 2 Lithium-molybdenum disulphide
secondary batteries
Performance characteristics of sealed lithium-molyb-
0 4 8 12 16 20 denum disulphide cells are compared with those sealed
Years cylindrical sintered plate nickel-cadmium batteries in
Table 9.15.
Figure 9.10 Catalyst Research Corporation lithium-iodine Pace- Lithium-molybdenum disulphide cells have a
maker Model 802/23; projected performance over 20 years
(Courtesy of Catalyst Research Corporation) 40-50% higher voltage than nickel-cadmium. Their