Next Generation Materials for Lithium-Ion Space Batteries

Abstract

EaglePicher has been supplying batteries for energy storage for satellites and other space applications since 1958. These batteries have achieved over 2.6 billion hours of cell operations with no failures in orbit. Over the decades the battery chemistry has changed amongst various chemistries with some overlap and some still being used today. Typical space battery chemistries include: silver-zinc, nickel-hydrogen, nickel-cadmium, and then lithium-ion. Even within the lithium-ion chemistry the formulations and packaging has evolved over time and continues to change. Lithium-ion space batteries continue to evolve today. New satellites and space applications are demanding increased energy, more power, and smaller volumes. This has led to improvements in increased energy, wider operating temperatures, more power and smaller packages. Every change in battery performance requires new or modified battery materials. For increased energy the incumbent cathode material for lithium-ion batteries is Lithiated Nickel Cobalt Oxide (NCO). This was changed to the Lithiated Nickel Cobalt Aluminum Oxide to increase the energy and improve cycle life. For wider operating temperatures the electrolyte formulation has evolved with new components and additives. Newer and next generation satellites are carrying state of the art instruments that demand high power or pulses of power. New lithium-ion battery chemistries have been developed to supply very high power discharges to supply the large currents. As small satellites are increasing in popularity, there is a push for smaller battery packs. This has led to a decrease in cell capacity and the introduction of commercial of the shelf (COTS) cells. These are often cylindrical in shape and typically 18650 in size. Transitioning to COTS cells has increased the ability to create modular space batteries, but has brought up new concerns on quality and reliability. Quality and reliability, plus safety, are top concerns for space batteries. Replacement of batteries in space is extremely difficult and expensive. As each of the next generation battery materials are developed, reliability and safety much be eminent. These materials and batteries are often expected to supply power for decades. The continued testing, evaluation and analysis of the new chemistries and designs provides assurances for long-term performance and reliability. As these batteries have the potential to power satellites, landers, rovers, capsules, and habitats, EaglePicher continues to develop, evolve, demonstrate, and produce new battery chemistries and designs to meet the mission requirements. Acknowledgements We would like to thank: NASA JPL, Lockheed Martin and the Unites States Government for supporting some of this effort, and many of the EaglePicher employees who worked on these projects.