Thermografische Methoden zur zerstörungsfreien Messung der anisotropen Wärmeleitfähigkeit von Lithium-Ionen-Zellen

Arzberger, Arno; Sauer, Dirk Uwe (Thesis advisor); Kneer, Reinhold (Thesis advisor)

Aachen : ISEA (2020, 2021)
Book, Dissertation / PhD Thesis

In: Aachener Beiträge des ISEA 143
Page(s)/Article-Nr.: 1 Online-Ressource (iv, 131 Seiten) : Illustrationen, Diagramme

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2020

Abstract

In particular, the increasing demands for fast charging capability require effective thermal management of traction batteries. It is based on the exact knowledge of the thermophysical properties of the battery cells used. Based on the established flash method, a novel approach to non-destructively measure the anisotropic thermal conductivity of lithium-ion cells is presented. Evidence is provided that the electrode composite can be conceived as a homogeneous body with anisotropic properties in the measurement. The main section of the thesis describes the experimental setups for measuring pouch cells, cylindrical cells, and prismatic cells. Measurement evaluation models known from the literature are tested for their robustness and further developed. Because of their geometrical similarity to the typical sample geometry for measurement in laboratory apparatus, the transfer of the flash method is initially made to pouch cells. By introducing inductive thermal excitation, the principles developed can finally be transferred to cylindrical cells and prismatic cells. The flash method, which underlies all measurement setups, requires non-contact, radiation-based temperature sensing that operates without time delay. Because of its special challenges, a separate chapter is devoted to temperature measurement with the thermal imaging camera. The methods presented were primarily developed for the measurement of lithium-ion cells. However, they can be directly applied to the measurement of other bodies if the necessary requirements are met.