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Dr. Foad Heidari Gandoman: Concept of Reliability Assessment in the NickelManganese-Cobalt Lithium-ion Battery Technology for EVs Application

PhD Cover Foad Heidarie Gandoman

Over the last few decades, Lithium-ion (Li-ion) batteries have attracted significant attention due to their high energy density, low maintenance, and variety of shapes, chemistries, and performances available. Meanwhile, the concept of reliability and safety assessment of the Li-ion batteries have become essential issues for Original Equipment Manufacturers (OEMs). Evaluation of reliability plays a critical role in assessing overall a Li-ion battery behaviour over its lifespan. The primary gap definition of the reliability assessment of Li-ion batteries are i: Reliability indicators and their connection with degradation modes, degradation mechanisms, and degradation conditions, ii: Multi degradation conditions (different temperatures and C-raters) need to implement on the Li-ion batteries to investigate their effect on the reliability indicators, iii: The reliability assessment of the Li-ion battery from the time-domain, iv: Investigation of degradation conditions and their comparison from the reliability standpoint.

To fulfil these objectives, capacity fade, power fade, and battery open-circuit voltage (OCV) variations have been introduced as three main reliability indicators in this dissertation. Moreover, quantitative technique and risk analysis have been taken into account for providing reliability assessment as solutions to existing challenges from the time domain. Additionally, Nickel Manganese Cobalt Oxide (NMC) cylindrical Li-ion battery due to high domain operating temperature and discharge C-rate has been used to cover the evaluation from different degradation conditions. Also, due to the nonlinear behaviour of the Li-ion batteries, power fade and OCV variations in three critical State of Charge (SoC) windows (80%, 50%, and 20%) have been evaluated. The main objectives of this dissertation are summarized as below:

  • A comprehensive study on the degradations of Li-ion batteries in regular operation.
  • The contribution of degradations in failure modes, based on power fade, and capacity fade, and OCV variations in Li-ion batteries,
  • Impact of degradation conditions on the reliability of Li-ion batteries, 
  • A new investigation for lifetime performance of the Li-ion batteries based on the reliability indicators (Power fade, Capacity fade, OCV variations) to provide a high and low reliable operating zone at different C-rate and ambient temperatures.