Choosing a Battery that will last Does high energy density jeopardize long service life?

摘要

Research has brought about a variety of battery chemistries, each offering distinct advantages but none providing a fully satisfactory solution. However, with today's selection of battery systems, better choices can be made to tailor to specific user applications. Relentless downsizing has pressured manufacturers to invent smaller battery sizes. By packing more energy into a pack, other qualities may be neglected, one of which is longevity. Long service life and predictable low mΩ reading are found in the NiCd family. However, this chemistry is being replaced, where applicable, with systems containing higher energy density. In addition, negative publicity about the memory phenomenon and concerns of toxicity in disposal are causing equipment manufacturers to seek alternative choices. Once hailed as the superior battery system, the NiMH has also failed to provide the universal battery solution for the twenty-first century. Shorter than expected service life remains a major complaint by users. For a fast-moving consumer market that replaces the equipment every two years, the Li-ion battery is the best choice. The aging factor is of little concern. However, for applications that need fully charged batteries that often must be kept in warm storage conditions, the Li-ion does pose a problem in terms of longevity. So far, the emerging lithium polymer system has been unable to overcome the shortcomings of the Li-ion. Other than lighter packaging and more flexible design, the Li-Polymer, as we know it today, may not yet offer the ultimate solution to portable power. With the rapid developments in technology occurring today, battery systems may soon become viable that use neither nickel, lead nor lithium. Fuel cells, which do not rely on electro-chemical process but allow refueling similar to a vehicle, may solve the portable energy needs for the future. Instead of a charger, the user carries a bottle of liquid energy. Such a battery would truly change the way we live and work.