High Performance Lithium Ion Aircraft Battery for DoD Platforms 2008-01-2885

This paper describes a development project at Electro Energy designed to develop a high performance aircraft battery which will be suitable for use in many DoD aircraft platforms. The goal is to provide a safer high energy and power battery for aircraft energy storage systems. Aircraft batteries used on military aircraft battery platforms have a low reliability and require significant maintenance and as a result have significant costs associated with them beyond the initial procurement cost. It is desirable to develop state of the art aircraft batteries which have high reliability and minimal maintenance costs. Lithium ion cells can be employed to produce a lithium ion aircraft battery which will have significant advantages over the present nickel cadmium and lead acid aircraft batteries. The lithium ion battery will have higher specific energy, increased energy density, improved cycle life, and lower maintenance requirements. Prior projects with Electro Energy Inc. have shown increased low temperature performance and better capacity per unit volume and weight.

The relationship between electrode parameters and the discharge performance of high rate batteries has been discussed previously in characterizing the rate capability of the LiCoO₂ electrode by Abraham et al (Discharge Rate Capability of the LiCoO2 Electrode”, J. Electrochem. Soc., 145, 482, 1998). The cathode material LiNi_0.33Mn_0.33Co_0.33O₂ (NMC) has been identified as an excellent candidate for development of a robust positive electrode. NMC has the potential to provide a superior safe high rate cathode compared to LiCoO₂. The proper parameters to achieve optimum compaction for the electrode while leaving adequate porosity in the electrode structure for electrolyte penetration and wetting is also critical to the development of a high performance lithium ion aircraft battery. This development project includes a review of anodes, cathodes, electrolytes, additives, compositions and manufacturing processes in a wafer cell battery configuration to meet the performance requirements of DoD aircraft batteries. Cathode materials were evaluated from three different suppliers and particle sizes from 4 to 10 microns were tested for energy storage and power density. Investigations were conducted on the effects of particle size of the electrode materials and thickness of the electrode on rate capability. An initial design for a 28 volt module and 270 volt aircraft battery has been developed. Test data shows that it will be possible to achieve the initial technical objective of this effort which is to develop a lithium ion cell that will meet the aircraft battery requirements, including fast discharge and recharge over the DoD operating temperature range.