A hybrid NMC–LFP lithium-ion battery architecture for UAV applications: Maximising energy readiness and minimising calendar aging

Monolithic lithium-ion (Li-ion) battery designs continue to pose challenges in meeting diverse application requirements. This paper proposes a solution by introducing a novel hybrid battery architecture that considers combining two different Li-ion chemistries to mitigate each other's limitations. The potential of this concept is demonstrated by considering the application of unmanned aerial vehicles (UAVs) used for emergency deployment, which require high energy density during deployment and good longevity during their long off-duty periods. For the given application, the study identifies the optimal capacity proportions for the hybrid architecture using nickel manganese cobalt (NMC) and lithium iron phosphate (LFP) chemistries to balance energy availability and degradation, while keeping the change in weight, volume, and cost within acceptable limits compared to a typical single-chemistry battery pack. The optimal configuration showed an improvement of up to 35% in energy availability with a mere increase of less than 1% in calendric degradation compared to existing single-chemistry battery packs used for the same application. However, the weight and volume were penalised by 8%, while the cost dropped by around 4%. This result shows that no single hybrid configuration is universally optimal. The paper thereby establishes the broad potential that the architecture carries in a wide context.