|Acquisition Program: ||PM Future Combat Systems Brigade Combat Team|| Objective: ||Increase the operational temperature range of prismatic laminate lithium ion battery cells through electolyte and materials improvements which allows transition of these batteries to Army ground vehicles without the overhead of specialized heating and cooling systems.
|| Description: ||Lithium ion battery cells can be designed to operate in a variety of temperature ranges. However, the width of the operational tempterature range can be a limiting factor for military applications, which require operation in envionments from -50 deg C to 70 deg C. At low temperatures the electrolyte becomes more viscous and resistance is increased, resulting in poor battery performance. At high temperatures electrolyte can become unstable and participate in side reactions with other battery components, such as the electrode active materials. Additionally, at high temperatures cell components such as the separator may melt, causing cell failure. Finally, the prismatic laminate type cell is of particular interest to the Army because of it’s potential for dual-use application in both military and commercial automotive vehicles. This cell design is advantageous in commerical vehicle applications because it can accomidate large capacites and is scalable for a variety of battery pack configurations. As a result, many automotive companies are moving to prismatic laminate cells for their hybrid and electric vehicle applications. The Army wishes to leverage the market for these cells for military vehicle applications. However, at high temperatures this cell type suffers from an additional failure mode because the cell packaging can melt.
To this end, the Army is soliciting proposals to research and develop new lithium ion prismatic laminate cells capable of operating in a temperature range of -50 deg C to 70 deg C. Proposals should address the capability of both the external packaging materials and internal components (electrolyte, separator) to operate at this temperature range. The newly developed cells should exhibit a minium cycle life of 300 cycles at both the high and low temperature extremes and have performance characteristics similar to typical lithium ion cells at room temperature. Futher, at low temperatures, the cells should exhibit capacities of at least 50 percent of their rated capacity.
|| ||PHASE I: Develop and demonstrate electrolytes, materials, and/or packaging techniques to allow wide operational temperature range in lithium ion prismatic laminate cells. Perform feasibility testing on commercial format cells to show cell operation in the extended temperature range. Results of the research and testing shall be provided in report form as deliverables for Phase I.
|| ||PHASE II: Produce several prototype prismatic laminate cells of at least 10 Ah capacity each. Integrate the cells into a 6T size battery pack with a battery management system to demonstrate their applicability to military platforms. Results of the development effort and testing shall be provided in report form as deliverables. Additionally, cells and packs produced under the effort shall be delivered to the Army for independent evaluation.
|| ||PHASE III: The resulting technology will feed into the non-primary power system ATO to develop advanced batteries suitable to be intregrated into current Army ground vehicle platforms. It will also enable increased performance of commercial hybrid electric vehicles. Markets for the technology include Military Vehicle OEMs, battery manufacturers, and commercial hybrid electric vehicle OEMs.
|| References: ||
1. T. R. Jow, M. S. Ding, K. Xu, S. S. Zhang, J. L. Allen, K. Amine and G. L. Henriksen, “Nonaqueous electrolytes for wide-temperature-range operation of Li-ion cells", J. Power Sources, 119-121(2003)343.
2. M.C. Smart, B.V. Ratnakumar, and L. D. Whitcanack, “Assessment of Various Low Temperature Electrolytes in Prototype Li-ion Cells Developed for ESMD Applications”, 6th International Energy Conversion Engineering Conference (IECEC), 28 - 30 July 2008, Cleveland, Ohio.
3. Thanthrimudalige D. J., Dunstan, Josip Caja, “Lithium-ion cell with a wide operating temperature range", US Patent 7582380.|
|Keywords: ||lithium ion, batteries, electrolyte, separator, packaging, temperature range|