December 30th, 2022
Before purchasing an electric vehicle, all eyes are on the battery: Among first questions concerning range anxiety and charging speed, most people ask how much loss of capacity the battery will suffer over its average useful life. In this podcast, we talk about (the very normal) degradation of batteries, state of health (SOH) measurements and the research of predicting a battery’s lifetime.
Our podcast guest for this episode is Prof. David Howey. He is a British Professor of Engineering Science at the University of Oxford and holds a Tutorial Fellow at St Hilda’s College. His research is focused on modelling and managing energy storage systems, for electric vehicles as well as grid and off-grid power systems.
Battery state of health (SOH) is a measurement that indicates the level of degradation and remaining capacity of the battery. Expressed in a simple way, it describes the difference between the health of a new battery and the health of a used battery. Typically, this is represented as a percentage of its initial capacity and performance.
According to Prof. Howey’s expectations, most EV batteries are projected to last hundreds of charging cycles (most LiBs) without a noticeable loss in SOH. However, EV batteries do age over time even if the battery isn’t used at all.
Apparently, there are always minor losses in battery capacity: Especially fast charging does harm the battery in case of a bad thermal battery management. At higher temperatures, one of the effects on lithium-ion batteries’ is greater charging performance & lower degradation. That’s why many EVs heat their batteries up before charging them at higher speeds. In winter times, when temperatures are low outside, this can get quite important when looking at a high life-expectancy of an EV’s battery.
