Page 370 - Lindens Handbook of Batteries

LiTHiUM PriMAry BATTerieS 14.35

3.6
3.4
3.2
3.0
Cell voltage, V 2.8
2.6
2.4
2.2 2.0 ohms/1.6 A 2.5 ohms/1.33 A 5 ohms/690 mA 10 ohms/350 mA 50 ohms/70 mA
2.0
1.8
1.6
0.01 0.1 1 10 100 1000
Time, h
FIGURE 14.25 Discharge characteristics of spirally wound Li/SOCl D-size battery, medium discharge rate at
2
20°C. (Courtesy of SAFT Batteries.)

is laser sealed or welded to provide an hermetic closure. Safety devices, such as a vent and a fuse or
a PTC device, are incorporated in the cell to protect against buildup of internal pressure or external
short circuits.
The discharge curves for a D-size battery are plotted in Fig. 14.25, showing the higher perfor-
mance at moderate drains compared to the bobbin cell (see Fig. 14.17).
Figure 14.26 shows the performance characteristics of the D-size battery, providing the relation-
ship of voltage and capacity with current drain at several temperatures.
Like the other Li/SOCl batteries, these batteries have an excellent storage capability over a wide
2
temperature range due to the buildup of a protective lithium chloride layer on the lithium. Capacity
loss on storage at ambient conditions is stated to be less than 3% per year. These products are said to
be resistant to passivation. Table 14.12 lists the characteristics of typical cylindrical spirally wound
Li/SOCl batteries.
2

14.6.4 Flat or Disk-Type Li/SOCl Cells
2
The Li/SOCl system was also designed in a flat or disk-shaped cell configuration with a moderate
2
to high discharge rate capability. These batteries are hermetically sealed and incorporate a number of
features to safely handle abusive conditions, such as short circuit, reversal, and overheating, within
design limits.
The battery shown in Fig. 14.27 consists of a single or multiple assembly of disk-shaped lithium
anodes, separators, and carbon cathodes sealed in a stainless-steel case containing a ceramic feed-
through for the anode and insulation between the positive and negative terminals of the cell. 28
The batteries were originally manufactured in small and large diameter sizes by Altus Corp., and
are currently being produced in large sizes only for U.S. Navy applications by HeD Battery Corp.,
Santa Clara, CA. The characteristics of these batteries that are currently available are summarized in
Table 14.13. Discharge curves for large batteries are shown in Fig. 14.28. Typically the cells have a
high energy density, flat discharge profiles, and the capability of performance over the temperature
range of -40 to 70°C. On storage they can retain 90% of the capacity after storage of 5 years at 20°C,
6 months at 45°C, or 1 month at 70°C.