Page 341 - Lindens Handbook of Batteries

14.8 PriMAry BATTerieS

The electron moves through the external circuit to the cathode, where it reacts with the cathode mate-
+
rial, which is reduced. At the same time, the Li ion, which is small (0.06 nm in radius) and mobile in
both liquid and solid-state electrolytes, moves through the electrolyte to the cathode, where it reacts
to form a lithium compound.
A more detailed description of the cell reaction mechanism for the different lithium primary bat-
teries is given in the sections on those battery systems. 1,7

14.3 CHARACTERISTICS OF LITHIUM PRIMARY BATTERIES

14.3.1 Summary of Design and Performance Characteristics
A listing of the major lithium primary batteries now in production or advanced development and
a summary of their constructional features, key electrical characteristics, and available sizes are
presented in Table 14.6. The types of batteries, their sizes, and some characteristics are subject to
change depending on design, standardization, and market development. Manufacturers’ data should
be obtained for specific characteristics. The performance characteristics of these systems, under
theoretical conditions, are given in Table 14.4. Comparisons of the performance of the lithium bat-
teries with comparably sized conventional primary batteries are covered in Sec. 8.3. Detailed char-
acteristics of some of these batteries are covered in Secs. 14.5 to 14.11 and Sec. 31.5.4.

14.3.2 Soluble-Cathode Lithium Primary Batteries

Two types of soluble-cathode lithium primary batteries are currently available (Table 14.1). One
uses SO as the active cathode dissolved in an organic electrolyte solvent. The second type uses
2
an inorganic solvent, such as the oxychlorides SOCl and SO Cl , which serves as both the active
2
2
2
cathode and the electrolyte solvent. These materials form a passivating layer or protective film of
reaction products on the lithium surface, which inhibits further reaction. even though the active
cathode material is in contact with the lithium anode, self-discharge is inhibited by the protective
film, which proceeds at very low rates, and the shelf life of these batteries is excellent. This film,
however, may cause a voltage delay to occur, i.e., a time delay to break down the film and for the
cell voltage to reach the operating level when the discharge load is applied. These lithium batteries
have a high specific energy and, with proper design, such as the use of high-surface-area electrodes,
are capable of delivering high specific energy at high specific power.
These cells generally require a hermetic-type seal. Sulfur dioxide is a gas at 20°C (bp -10°C),
5
and the undischarged cell has an internal pressure of 3 to 4 × 10 Pa at 20°C. The oxychlorides are
liquid at 20°C, but with boiling points of 78.8°C for SOCl and 69.1°C for SO Cl , a moderate pres-
2
2
2
sure can develop at high operating temperatures. in addition, as SO is a discharge product in the
2
oxychloride cells, the internal cell pressure increases as the cell is discharged.
The lithium/sulfur dioxide (Li/SO ) battery is the most advanced of these lithium primary bat-
2
teries. These batteries are typically manufactured in cylindrical configurations in capacities up to
34 Ah. They are noted for their high specific power (about the highest of the lithium primary bat-
teries), high energy density, and good low-temperature performance. They are used in military and
specialized industrial, space, and commercial applications where these performance characteristics
are required.
The lithium/thionyl chloride (Li/SOCl ) battery has one of the highest specific energies of all the
2
practical battery systems. Figures 8.8 and 8.9 illustrate the advantages of the Li/SOCl battery over
2
a wide temperature range at moderate discharge rates. Figure 14.2 compares typical discharge profile
of the Li/SOCl cell with the Li/SO cell. At 20°C, at moderate discharge rates, the Li/SOCl cell has
2
2
2
a higher working voltage and about a 50% advantage in service life. The Li/SO cell, however, does
2
have better performance at low temperatures and high discharge rates and a lower voltage delay after