Rechargeable lithium cells

Fig. 1. Configuration for a soHd polymer electrolyte rechargeable lithium cell where the total thickness is 100 pm.

Efforts to commercialize larger versions of rechargeable lithium cells have been fmstrated by concerns over product safety. MoH Energy Ltd. briefly introduced "AA" Li—M0S2 cells for OEM use in laptop computers and cellular phones. However, safety issues resulted in a product recall and a halt to commercialization of this product. 

It should be noted that the rechargeable cells discussed later have the same construction and differ only in separator type, electrode composition and cathode / anode balance. For comparison, Fig. 3 shows the design of an AA-size lithium cell. The construction with a spirally rolled electrode increases the power output. 

In practical cases, however, the excess weight and volume due to the use of alloys may not be very far from those required with pure lithium electrodes, for one generally has to operate with a large amount of excess lithium in rechargeable cells in order to make up for the capacity loss related to the filament growth problem upon cycling. 

Some problems associated with the use of these anions have stimulated the search for substitutes [6], especially for rechargeable lithium cells. 

Huggins RA., Materials Science Principles Related to Alloys of Potential Use in Rechargeable Lithium Cells. J. Power Sources 1989 26 109-20. 

The available choice of lithium salts for electrolyte application is rather limited when compared to the wide spectrum of aprotic organic compounds that could make possible electrolyte solvents. This difference could be more clearly reflected in a comprehensive report summarizing nonaqueous electrolytes developed for rechargeable lithium cells, in which Dahn and co-workers described over 150 electrolyte solvent compositions that were formulated based on 27 basic solvents but only 5 lithium salts. ... 

In lithium ion rechargeable batteries, shutdown separators are used as part of the overall battery safety system. These devices prevent, or substantially reduce the likelihood of thermal runaway, which may arise from short circuiting caused by physical damage, internal defect, or overcharging. The shutdown separators, will shutdown by a sufficient pore closure to substantially stop ion or current flow within the cell (37). 

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