The lithium titanate anode, due to its high surface area (100 m(2)/g compared to 3 m(2)/g for the graphite based anode) performs much better in this respect. At higher charging rates of 5I(t) or more, the internal resistance impedes charge acceptance by high energy cells. Lithium-ion batteries are able to store about 80% of the capacity at current rate 2I(t), with high power cells accepting over 90%. Furthermore, rate capabilities during charging have been investigated. The rate capabilities tests are reflected by Peukert constants, which are significantly lower for lithium-ion batteries than for nickel-metal hydride and lead-acid. The study of the rate capability of the lithium-ion batteries has allowed for a new state of charge estimation, encompassing all essential performance parameters. Their association with electric-double layer capacitors, which have low energy density (4-6 Wh/kg) but outstanding power capabilities, could be very interesting. Lithium-ion batteries optimized for high energy are at the lower end of this range and are challenged to meet the United States Advanced Battery Consortium, SuperLIB and Massachusetts Institute of Technology goals. However, considering the influence of energy efficiency, the power density is in the range of 100-1150 W/kg. The power density is in the range of 300-2400 W/kg against 200-400 and 90-120 W/kg for lead-acid and nickel-metal hydride, respectively. Also the power capacity of lithium-ion technology is superior compared to other technologies.
The efficiency varies between 86% and 98%, with the best values obtained by pouch battery cells, ahead of cylindrical and prismatic battery design concepts. The dynamic discharge performance test shows that the energy efficiency of the lithium-ion batteries is significantly higher than the lead-acid and nickel-metal hydride technologies. These values are considerably higher than the lead-acid (23-28 Wh/kg) and nickel-metal hydride (44-53 Wh/kg) battery technologies. Particularly, the nickel manganese cobalt oxide cathode stands out with the high energy density up to 160 Wh/kg, compared to 70-110, 90 and 71 Wh/kg for lithium iron phosphate cathode, lithium nickel cobalt aluminum cathode and, lithium titanate oxide anode battery cells, respectively.
The analysis has shown the beneficial properties of lithium-ion in the terms of energy density, power density and rate capabilities.
In this paper, the performances of various lithium-ion chemistries for use in plug-in hybrid electric vehicles have been investigated and compared to several other rechargeable energy storage systems technologies such as lead-acid, nickel-metal hydride and electrical-double layer capacitors.
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