Modelling the transient behaviour of lead-acid batteries : electrochemical impedance of adsorbed species

• Modellierung des transienten Verhaltens von Blei-Säure Batterien : Elektrochemische Impedanz von adsorbierten Spezies

Huck, Moritz; Sauer, Dirk Uwe (Thesis advisor); Kowal, Julia (Thesis advisor)

Aachen : ISEA (2020)
Book, Dissertation / PhD Thesis

In: Aachener Beiträge des ISEA 146
Page(s)/Article-Nr.: 1 Online-Ressource (vii, 151 Seiten) : Illustrationen, Diagramme

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2020

Abstract

Lead-acid batteries are known for more than one century. The fast changing requirements for battery technologies during the last decade have shown that the lead-acid is not well understood. Electrochemical Impedance Spectroscopy (EIS) is a versatile technique for examining transient processes. To understand the resulting spectra, the EIS measurement have to be compared to model calculations. Usually Electrical Equivalent Circuits (EEC) are used to analyse EIS measurements. EEC are insufficient to explore the underlying reactions and mechanisms which results in the EIS spectra.In this work, a model is developed that is based on continuity equations. This model can simulate EIS spectra, which allows comparing EIS measurements with simulated EIS spectra.The model covers effects with fast time constants like the electrochemical reactions and the charging of the electrochemical double layer at the electrode-electrolyte interface. In addition, effects with slower time constants like the electrolyte diffusion or the precipitation and dissolution of lead sulphate are covered. For the crystal precipitation, growth and dissolution a specific model is employed which has a reduced state space. The reduced state space allows simulating the crystal distribution on fine FEM mesh.The presented model can simulate realistic EIS spectra in the frequency domain and shows realistic transient behaviour in the time domain.