Lithium-thionyl chloride cells

Lithium—Thionyl Chloride Cells. Lidiium—thionyi chloride cells have very high energy density. One of the main reasons is the nature of the ceU reaction. 

Lithium tetrahydridothallate(III), 24 632 Lithium tetrahydroborate, physical properties of, 4 194t Lithium—thionyl chloride cells, 3 466 characteristics, 3 462t speciality for military and medical use, 3 430t... 

Fig. 4.35 Discharge curves of D-size lithium-thionyl chloride cells at ambient temperature (a) 3.0 A (b) 1.0 A (c) 0.1 A...

Lithium-thionyl chloride cells are also constructed as reserve batteries... 

The energy density of liquid cathode lithium cells can be further enhanced to over 500 Wh/kg (1000 Wh/dm3) by the use of halogen additives. BrCl, added to lithium-thionyl chloride cells, boosts the OCV to 3.9 V and prevents the formation of sulphur in the early stages of discharge. D-sized cells are manufactured, Addition of chlorine to lithium-sulphur yl chloride cells increases the energy density and improves the temperature-dependent electrical characteristics. 

Liquid Cathode Cells. Liquid cathode cells include lithium-sulfur dioxide cells and lithium-thionyl chloride cells. 

The rate of this process in aprotic electrolytes is rather high the exchange current density is fractions to several mA/cm. As pointed out already, the first contact of metallic lithium with electrolyte results in practically the instantaneous formation of a passive film on its surface conventionally denoted as solid electrolyte interphase (SEI). The SEI concept was formulated yet in 1979 and this film still forms the subject of intensive research. The SEI composition and structure depend on the composition of electrolyte, prehistory of the lithium electrode (presence of a passive film formed on it even before contact with electrode), time of contact between lithium and electrolyte. On the whole, SEI consists of the products of reduction of the components of electrolyte. In lithium thionyl chloride cells, the major part of SEI consists of lithium chloride. In cells with organic electrolyte, SEI represents a heterogeneous (mosaic) composition of polymer and salt components lithium carbonates and alkyl carbonates. It is essential that SEI features conductivity by lithium ions, that is, it is solid electrolyte. The SEI thickness is several to tens of nanometers and its composition is often nonuniform a relatively thin compact primary film consisting of mineral material is directly adjacent to the lithium surface and a thicker loose secondary film containing organic components is turned to electrolyte. It is the ohmic resistance of SEI that often determines polarization of the lithium electrode. 

When discussing cathodes for primary cells, it is important to make a distinction between solid materials, mentioned above, and those in which the cathode electrochemical component is not in the physical electrode structure, but rather exist in a liquid or gas state. Examples include zinc air cells, lithium thionyl chloride cells, and lithium sulfur dioxide cells. In each case, the physical cathode stmcture serves as a catalytic reaction... 

TABLE 14.14 Performance Characteristics of 1000 Ah LMRS Lithium/Thionyl Chloride Cells and Batteries (Number of Cells Tested Indicated in Parenthesis After Each Test)... 

Catalysts are an important part of metal-air batteries and have been investigated for use in lithium-thionyl chloride cells also. Metal-air batteries are very similar to fuel cells and have been called fuel cell-battery hybrids because one of the electroactive materials, oxygen, does not require storage. 

Short circuiting of lithium-thionyl chloride cells with the risk of subsequent cell explosions have led to a limited use of these cells in particular areas, e.g. military and medical applications. 

The cell reaetions in the lithium-thionyl chloride cell are postulated as follows ... 

Discharge performance data for an active lithium-thionyl chloride cell are shown in Figure 30.19. Figures 30.20 and 30.21 compare the discharge performance of lithium-thionyl chloride batteries at -29 and 24°C. 

Figure 30.19 Honeywell lithium-thionyl chloride cell (Q3037) Spacecraft B cell discharge profile at 30°C storage at 29 4.5°C capacity 381 Ah energy density 973Wh/dm, 563Wh/kg (Courtesyof Honeywell)...

Figure 30.35 shows the effect of battery temperatures on available capacity for a lithium-thionyl chloride 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. 

Applications for lithium-thionyl chloride cells and active batteries include all those for which active lithium-sulphur dioxide cells and batteries are recotmnended, and also high-temperature applications. 

Eagle Richer recommend their active lithium-thionyl chloride cells for micropower sources in advanced application areas, e.g. airborne instrumentation, undersea communications, mineral exploration, remote site monitoring safety controls, security, and space and/or defence systems. 

Other applications of lithium-thionyl chloride cells include utility metering gauges, security alarm systems, automobile electronic systems and well logging, electronic applications, e.g. power back-up for volatile random access memories. The US Army has placed large orders for the BA 6598 lithium-thionyl chloride battery produced by Eveready. There are no significant industrial or consumer applications to date for high rate woimd lithium-thionyl chloride cells. 

Table 56.10 Honeywell hermetically sealed lithium-thionyl chloride cells... 

Figure 56.8 SAFT LS210, 3,5 V, 500mAh lithium-thionyl chloride cell capacity ver us current drain chart at 20°C, discharge to 2 V...

SAFT lithium-thionyl chloride cells exhibit a highly stable service voltage and a far greater capacity than conventional zinc-manganese dioxide and carbon-zinc cells of the same size and configuration. 

Other suppliers of lithium-thionyl chloride cells include reserve type Yardney GJS), Philips USFA BV (Holland), Power Conversion Ltd (US), SAFT. Silberkraft, (Germany) and Sonnenschein, (Germany) active type Battery Enginccnng Co. (US), Crompton Eternaceil (UK), Electrochemical Industries (Japan), Hitachi Maxell (Japan), Power Conversion Ltd (US), Tadiram (Korea), Yardney (US) and Eveready (US). 

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