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2007


Development of Very Large Lithium-ion Batteries for Telecommunication Applications

Takefumi Inoue

Kanemi Komada

Hiroaki Yoshida

Mikio Iwata

Takihiro Ida



Currently, lead-acid batteries are used as a back-up power source for telecommunication applications. Lead-acid batteries are a very mature technology and have a long history of use in the industry, and as such, its operating and life parameters are fairly well understood. However, in the case of deployment in multi-story buildings, a lighter and smaller battery is required to reduce the floor weight loading, even though the power and energy requirements are not reduced. Lithium-ion batteries have much higher specific energy and energy density that enable a 70% reduction of weight and volume compared with lead-acid batteries. Therefore, a 200Ah and 400Ah class Lithium-Ion battery has been developed which can meet the energy storage and weight and volume requirements of the application. These batteries show approximately 30% of the weight and volume of lead acid batteries and also demonstrate excellent discharge performance even in low temperature environments. Moreover, since the lithium-ion cell voltage is 4V per cell, it reduces the number of cells connected in series to meet the same total system voltage. As for maintenance, the lithium-Ion battery is maintenance free: it is hermetically sealed, it has no memory effect, and it requires no electrolyte level adjustment like flooded lead acid and nickel cadmium batteries. The life performance of this new lithium-ion battery is being evaluated, and to date it shows almost the same performance as previously demonstrated with smaller cells using the same chemistry.


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