Lithium sulphur cells cell voltage

The lithium-sulphur dioxide cell has an open circuit voltage of 2.92 V at 20°C and a typical voltage under... 

Lithium-sulphur dioxide cells are available in a variety of cylindrical cell sizes from companies such as Honeywell and Duracell International, capacities available ranging from 0.45 to 21 Ah. Larger cells are under development. A number of the cells are manufactured in standard ANSI (American National Standards Institute) cell sizes in dimensions of popular conventional zinc primary cells. While these single cells may be physically interchangeable, they are not electrically interchangeable because of the high cell voltage of the lithium cell. 

After extended storage, a reactivation time of the order of a few seconds is required for the system to achieve operating voltage. This is not a feature exclusive to lithium-sulphur dioxide cells, but one which is also exhibited by lithium-vanadium pentoxidc and lithium-thionyl chloride cells. 

Figure 56.3 Mallory primary lithium-sulphur dioxide cells typical performance on constant-resistance load. End-point voltage 2.0 V (Courtesy of Mallory)...

Practical open-circuit voltages of the lithium-poly carbori-mono fluoride and lithium-sulphur dioxide systems are approximately 2.8 V and 2.9 V respectively at 20°C. The high voltage means that these batteries are not interchangeable with other electrochemical systems in existing equipment, unless a dummy cell is also included. 

Three principal types of lithium organic electrolyte battery are currently available the lithium-thionyl chloride system, the lithium-vanadium pentoxide system and the lithium-sulphur dioxide system. These batteries all have high-rate capabilities. The approximate open-circuit equilibrium cell voltages for these various cathode systems and for some other systems that have been considered are shown in Table 9.2. 

Figure9.5 Voltage discharge profile of llthlum-vanadlum pen-toxide (VzOa), lithlum-thionyl chloride (SOCIj), lithium-sulphur dioxide (SO2) lithium-molytxfenum trioxide (M0O3) cells (Courtesy of Honeywell)...

This system uses a lithium anode and a gaseous cathode dissolved in an inorganic electrolyte. It has a 3.63 V open-circuit voltage and a typical voltage under rated load of 3.2-3.4V. Like the lithium-sulphur dioxide system, it has a very flat discharge profile through 90% of its life. Cell construction is similar... 

Mallory supply hermetically sealed lithium-sulphur dioxide organic electrolyte cells in the capacity range 1.1-lOAh with a nominal voltage of 3.00V. Further details are given in Tables 56.2 and 56.3. Discharge curves for two of these batteries are given in Figure 30.15. 

Hazardous incidents have been experienced with some lithium systems, particularly those using sulphur dioxide and thionyl chloride cathodes. These incidents generally occur at later stages in battery life under reverse current conditions, during voltage reversal and while operating at high temperatures. Safety incidents have not been experienced with lithium-iodine cells, which is why they power 90% of the cardiac pacemakers presently in use. 

Figure 56.5 shows typieal diseharge eurves for a lithium-sulphur dioxide 3V cell supplied by Silberkraft. Load-eapaeity and load-voltage plots for the same battery are reprodueed in Figure 56.6. The G06 and G32 eells (see Table 56.7) and the G03 cell are partieularly reeommended for power supply for CMOS back-up applications. With these cells, simply by diode...

Figure56.6 Silberkraft type 440 (renumbered 932) lithium-sulphur dioxide 3V, O.SAh cell load capacity and load voltage curves (same battery as in Figure 56.5) (Courtesyof Silberkraft)...

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