Eduardo Redondo-Iglesias

Influence of the non-conservation of SoC value during calendar ageing tests on modelling the capacity loss of batteries

This paper presents a methodology for modelling the capacity loss of Lithium ion cells in accelerated ageing tests. We have considered the state-of-charge drift during calendar ageing tests due to irreversible capacity losses.

Measuring Reversible and Irreversible Capacity Losses on Lithium-Ion Batteries

In this paper we present an innovative and precise way to calculate the available capacity in a battery. This quantity is essential to assess the ageing process during real use or ageing tests. The most common way to measure the battery capacity consists on a constant current discharge. It is quite simple to implement but very dependent of impedance and relaxation state of the battery. Consequently, this method is not suitable to quantify reversible and irreversible capacity losses occurring on batteries. We propose an indirect measure of available capacity that reduces the distortion caused by battery relaxation and impedance changes.

Calendar and cycling ageing combination of batteries in electric vehicles

Abstract The battery is the most sensitive part in the powertrain of full electric vehicles because of its cost and weight. The full electric vehicle range and prize are highly determined by the battery performances. During its lifespan, the battery performances are degraded because of ageing mechanisms. Typically, there are two types of ageing: calendar and cycling ageing. In the electric vehicle application, both types of ageing coexist and interact. In this paper, we report the results of accelerated ageing tests and present a methodology to separate calendar from cycling ageing. With this analysis method, we demonstrate the interaction between calendar and cycling ageing when battery is cycled following representative current profiles of the electric vehicle application.

Global Model for Self-Discharge and Capacity Fade in Lithium-Ion Batteries Based on the Generalized Eyring Relationship

In this paper, we present an innovative and precise way to calculate the available capacity in a battery. This quantity is essential to assess the ageing process during real use or ageing tests. Classical methods for measuring the available capacity in a battery are very dependent of impedance and relaxation state of the battery. Consequently, these methods are not suitable to quantify reversible and irreversible capacity losses occurring on batteries. We propose an indirect measure of available capacity that reduces the distortion caused by battery relaxation and impedance changes. This new method provides more accurate results allowing to distinguish reversible from irreversible part of capacity losses. The obtained results on calendar ageing tests are used in a second part to model both self-discharge and capacity fade in a global approach by using the generalized Eyring relationship.

Impact of battery ageing on e-mobility energy efficiency

This paper focuses on energy efficiency degradation of two lithium-ion technologies, NMC (Nickel Manganese Cobalt) and LFP (Lithium Iron Phosphate), under accelerated calendar ageing tests. Results reveal the importance of considering battery ageing in the design phase of electric vehicles, not only for capacity but also for energy efficiency reasons.