Page 408 - Lindens Handbook of Batteries

LiTHiUM PriMAry BATTerieS 14.73

14.9.5 Applications and Handling
The applications of the Li/CFx battery are similar to those of the other lithium/solid-cathode batter-
ies, again taking advantage of the high specific energy and energy density and long shelf life of these
batteries. The Li/CFx coin batteries are used as a power source for watches, portable calculators,
memory applications, and electronic translators. The low-capacity miniature pin-type batteries have
been used as an energy source for LeDs and for fishing lights and microphones. The cylindrical bat-
teries can also be used in memory applications, but their higher drain capability also covers use in
cameras, electrical locks, emergency signal lights, and utility meters. The very large cells (Table 14.21b)
are used for military and space applications.
Handling considerations for the Li/CFx systems, too, are similar to those for the other lithium/
solid-cathode systems. The limited current capability of the coin and low-capacity batteries restricts
temperature rise during short circuit and reversal. These batteries can generally withstand this
abusive use even though they are not provided with a safety vent mechanism. The larger batteries
are provided with a venting device, but short circuit, high discharge rates, and reversal should be
avoided as these conditions could cause the cell to vent. Charging and incineration likewise should
be avoided for all batteries. The manufacturer’s recommendations should be obtained for handling
specific battery types.

14.9.6 Recent Advances in Lithium Carbon Monofluoride Technology
Use of Mixtures of Carbon Monofluoride and Manganese Dioxide. The use of both CFx and
MnO in the cathode of a lithium primary battery was first described in a U.S. patent issued in
2
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1982. This patent claims the use of mixtures of CFx and MnO but also claims a cell in which a
2
layer of CFx is disposed on top of a manganese dioxide layer. Little data is presented in this patent
to support the claims.
The high cost of carbon monofluoride relative to manganese dioxide has limited its use in many
48
applications. A recent report describes a study in which a mixture of CFx with x = 1 and heat-treated
MnO was used to construct a lithium primary D-cell. The proportions of the mixture were stated
2
to be a 50/50 blend, and the discharge curve shows two plateaus of approximately equal duration.
The cells were stated to have a balanced design. The electrolyte was only described as an inorganic
lithium salt in an organic electrolyte mixture. A co-polymer film separator was also used. The D cells
were discharged at 0.050, 0.250 and 2.0 A at 21°C and at 2.0 A at -30°C. results are summarized
Table 14.22. All three room-temperature discharge curves show two plateaus of approximately equal
duration. The 2.0 A discharge shows running voltages of 2.64 and 2.41 V, which are ascribed to
MnO and CFx, respectively. On 0.250 A discharge at 21°C, these cells exhibit a specific energy of
2
380 Wh/kg and an energy density of 923 Wh/L. These parameters represent increases of 35 and 57%
in specific energy and energy density compared to standard D cells using manganese dioxide only.
On 2.0 A discharge at -30°C, the cells with hybrid cathodes provide a capacity of 12.0 Ah, which is
79% of that obtained at 21°C at the same rate. This corresponds to a specific energy of 227 Wh/kg

TABLE 14.22 Performance Data for High-Capacity Li/CFx-MnO D-Cells at
2
Different rates and Temperatures to a 2.0 V Cutoff
Capacity Specific energy energy density
Temperature °C rate (A) (Ah) (Wh/kg) (Wh/L)
+21 0.050 16.6 407 990
+21 0.250 16.2 380 923
+21 2.0 15.2 338 823
-30 2.0 12.0 227 552