Sensitivity Analysis of Lithium-Ion Battery SoH Indicators: An Analytical Study

The aging processes of lithium-ion (Li-ion) batteries are complex, involving various State-of-Health (SoH) indicators. These mechanisms significantly impact the overall longevity of Li-ion batteries. Sensitivity Analysis (SA) of the terminal voltage to the SoH indicators provides insight into how each aging factor contributes to the battery's lifespan and performance. In this article, SA is applied to six SoH indicators, including, thickness of the Solid Electrolyte Interface (SEI) film in the negative electrode, electrolyte concentration on boundaries, lumped resistance, shell thickness on the positive electrode, volume fraction of active material, and reaction rate constant. Analytical derivation is employed as the SA approach. This generic approach empowers us to apply the results for all current inputs and different types of batteries with various parameters, avoiding data collection and fitting which are typically required in numerical methods. Single Particle Model with electrolyte (SPMe) dynamics is employed as the battery model. The simulation is performed on a Li-ion battery cell with manganese dioxide (Li, Mn
2
O
4
) and carbon (Li
x
, C
6
) as the positive and negative electrode, respectively, and an Urban Dynamometer Driving Schedule (UDDS) current profile.