Advances and trends in primary and small secondary batteries

Improvements in performance and reliability continue to be made in the traditional primary and secondary systems such as C-Zn, alkaline MnO ₂, Zn-air, Li-I, and sealed Ni-Cd and lead acid. In addition, two new secondary systems, Ni-metal hydride and lithium ion, have been introduced. They are growing rapidly in response to environmental concerns and the need for more energy density. Two new rechargeable sytems, Zn-air and lithium polymer are nearing commercial production. One manufacturer has introduced a rechargeable version of the alkaline MnO ₂ system for consumer use. Lithium primary systems, such as LiMnO2, Li-FeS ₂ and CFx are gaining substantial market share, amounting to about $500 million in 1992. Li-silver vanadium primary cells have been developed to supply the higher currents needed by implantable medical devices such as defibrillators. Most of the major producers have introduced "zero mercury" versions of alkaline MnO ₂ and zinc chloride cells in response to environmental pressure. New laws require that small rechargeable batteries in devices be labeled with instructions for disposal. Overall environmental concerns are likely to play a major role in the future of small batteries. Zn-HgO cells are on the way out and all major primary battery manufacturers are increasingly interested in small rechargeable types.<>