A Study on Degradation of Lithium-Ion Batteries for In Aircraft Applications

Abstract

Abstract Some lithium-ion batteries (LIBs) applications are mobile and stationary energy storage systems such as electric vehicles (full electric, hybrid and plug-in hybrid), different types of aircraft, and renewable energy technologies. LIBs can play a tremendous role in replacing the considerable dependence of nations on fossil fuels due to the high storage energy density of renewable energy alternatives. They also have a high cost associated with the material costs, as well as the other manufacturing costs. The environmental impact of manufacturing and disposing lithium-ion batteries has triggered actions to reduce the resulting impact by recycling batteries. Degradation of LIBs is always a concern for any application. To predict the life of cells correctly, it is more efficient to cover all mechanisms leading to capacity-fade or resistance growth. This study discusses the degradation rate of a LIB at two stages of life for both first- and second-uses. Empirical models can be used to measure capacity-fade, resulting from the battery degradation. The duty-cycle of the commercial LIB for a typical passenger aircraft, such as the Bombardier CRJ200, was obtained. For this purpose, the velocity and altitude of the aircraft were monitored during a typical flight, and the instantaneous mechanical power of the aircraft was obtained by modeling. Then, the duty-cycle of a LIB cell in the battery pack was yielded. The life prediction of the LIB in electrical energy storage for aircraft was studied. Although many studies have been done to evaluate performance and durability of LIB cells and packs for vehicle applications, there are very few studies of the application of LIBs in electric and hybrid aircraft. The degradation rate of the battery for a typical lightweight passenger aircraft with a flight range of less than 1000 km was then presented by using an empirical modeling method. The results showed that the A123 battery (20 Ah) degraded after 6 months at 45°C and 80% State of charge (SOC) and after 1.8 years at 45°C and 80% depth of discharge (DOD) by assuming that the battery should be retired when the rate of degradation reaches 15% of its nominal capacity. It was found that a retired first-use LIB cell is durable enough to be utilized in many second-use applications which can have lots of environmental benefits. Several items related to second use of LIBs will be discussed in this paper.