High power lithium secondary batteries
- Paper number
IAC-13,C3,P,12.p1,x18760
- Author
Mr. Honghui Gu, China
- Year
2013
- Abstract
Lithium-ion batteries, with their exceptional energy density and cycle life performance, are replacing other rechargeable battery systems in many applications. With the continued development of applications such as satellites, unmanned aerial vehicles and aircraft batteries, lithium-ion battery technology must continue to develop its high pulse power and high rate continue discharge performance aspects. The rate of the practice Li-ion batteries for space applicants are usually less than 1C, which can not afford to the high power load. Hence, it is necessary to develop high power Li-ion battery. While developing a cell with high rate performance characteristics, all aspects of the lithium-ion battery system are evaluated: anode material, cathode material, current collectors, electrolyte composition and separator. To improve the rate performance, the following strategies are often taken: firstly, reducing particle size or increasing surface area of active materials; secondly, lowing internal resistance including contact resistance between electrode materials and current collectors and between current collectors and cell case, particle and particle contact resistance within electrodes; finally, increasing conductivity of electrolytes especially at low temperatures. These strategies are quite effective in improving the rate considering the various charge transfer processes involved in charging and discharging. In this paper, three kind of high power Li-ion cells are proposed. The specific energy of prismatic high power 30Ah cells with LNCM and MCMB reached 140 wh/kg at 3C, and the cycle life was above 20000 cycles (20% DOD). 4Ah LiFePO4 lithium ion cell is capable of 250 A maximum continuous discharge and 300 A pulse discharge at 10s, reaching over 2000 w/kg. The cycle life at 1C discharge (100% DOD) can be over 500 cycles with excellent wide temperature performance. 5Ah high power soft-packed cells have a high rate capability with about 90% of baseline capacity (1C rate, room temperature) accessed at a 500 A (100C) rate of discharge, even up to 10 kw/kg for 2s short pulses. Based on the current research, Li-ion batteries with extremely high discharge, pulse and continuous power are manufactured. And the high power hermetically sealed cells will be the next research target.
- Abstract document
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