Lithium-Ion Battery Systems

The production of lithium-ion (Li-ion) batteries has been continually increasing since their first introduction into the market in 1991 because of their excellent performance, which is related to their high specific energy, energy density, specific power, efficiency, and long life. Li-ion batteries were first used for consumer electronics products such as mobile phones, camcorders, and laptop computers, followed by automotive applications that emerged during the last decade and are still expanding, and finally industrial applications including energy storage. There are four promising cell chemistries considered for energy storage applications: 1) LiMn₂O₄/graphite cell chemistry uses low-cost materials that are naturally abundant; 2) LiNi_1-X-Y2Co_XAl_YO₂/graphite cell chemistry has high specific energy and long life; 3) LiFePO₄/graphite (or carbon) cell chemistry has good safety characteristics; and 4) Li₄Ti₅O₁₂ is used as the negative electrode material in Li-ion batteries with long life and good safety features. However, each of the cell chemistries has some disadvantages, and the development of these technologies is still in progress. Therefore, it is too early to predict which cell chemistry will be the main candidate for energy storage applications, and we have to remain vigilant with respect to trends in technological progress and also consider changes in economic and social conditions before this can be determined.