Thermal Effects of Bad-Block-Management in an Intelligent Automotive Lithium-ion Battery Module based on lumped 3D Electro-Thermal Modeling

In conventional battery systems, single weak cells are limiting the overall performance or are critical for the battery's safety. In intelligent battery systems, reconfiguration enables the individual handling of single cells in the system by Bad-Block-Management (BBM). Thereby, the thermal situation within the battery is changed by the combination of the thermal influence by weak cells and the reconfiguration procedures by BBM. For an optimal reconfiguration strategy, multiple aspects need to be considered such as the cell individual parameters, safety state and position. In this work, the thermal effects of various BBM scenarios under electric vehicle conditions are investigated on the example of an intelligent lithium-ion module made of 12 prismatic cells. A hardware prototype of an intelligent module with switchable cells is investigated experimentally to quantify the effects of reconfiguration and provide validation data for the model development. The model is based on electro-thermal coupling of a 3D lumped thermal model and an equivalent circuit model of the cell with electronics and reconfiguration functionality. The model is used to investigate the temperature distribution with weaks cells within the module and the effects of several associated BBM procedures.