Representation of the crash relevant mechanical behaviour and features of a lithium ion battery with finite element simulation models at different scales

Marco Raffler*, Alexander Schmid, Florian Feist, Clemens Dünser, Georgi Kovachev, Jörg Moser, Christian Ellersdorfer, Eduard Ewert

*Corresponding author for this work

Research output: Contribution to conferencePoster


The lithium ion battery is the state of the art technology for traction batteries and therefore considered as a main key technology for the success of EV and HEV. The beneficial properties, such as high energy density, contribute to a higher acceptance of EV and HEV. On the other hand, due to the high energy density, the application of LIB poses considerable threat to health and environment, especially in vehicle crash load cases. Internal short circuit can occur under certain circumstances, such as electrical, thermal or mechanical loading, potentially leading to thermal runaway, fire and the release of hazard substances.1 To ensure a high level of safety of EV and HEV, crash simulations are performed throughout the development of the vehicle. In order to be able to estimate the risk for failure upon impact loading, accurate simulation models of cells are required. However, this is challenging, as the jelly roll and its components show complex properties, such as anisotropy, strain rate dependence and SOC dependence.
In this study an overview of model features that are required for finite element simulation models of a lithium ion pouch cell is given and their implementation in two distinct model approaches is presented: A detailed layer model (DLM) and a simplified applicable model (SAM) were developed whereby there were different requirements and challenges in both models.
The DLM is a very detailed model, where every single layer of the cell and the electrolyte is represented. It can be used for detailed single cell analysis, such as investigating the exact location of an internal short circuit, but due to the high computational effort, it is not suitable for simulations with a higher number of cells, i.e. at pack or module level. One main challenge for detailed models is to realistically represent the individual layers of the jelly roll and the interactions between the layers. In the DLM approach, a combination of 2D shell elements and 3D solid elements is used to create an accurate cell model that requires relatively little computational effort and is highly robust even under massive compressive loads, as it works without internal contact definitions. The SAM is a simplified model approach that can be used for full vehicle, pack, module and cell simulations. Due to the different purpose, SAM faces different challenges and requirements. It must comply with the full vehicle simulation requirements, such as minimum time step size or maximum number of elements. Still it must provide an accurate structural behaviour and reliable short circuit estimation. The SAM approach uses a combination of 1D beam, 2D shell and 3D solid elements to create an efficient simulation model that can represent the crash-relevant features while meeting the vehicle simulation boundary conditions.
Both models were calibrated on the basis of a comprehensive set of mechanical characterization tests at cell and cell component level. The validation of the models was performed with different quasi-static and dynamic cell tests.
With the development of these two novel simulation approaches for LIB, it is possible to represent the mechanical behaviour and to predict the cell failure under crash load at different scales.
Original languageEnglish
Publication statusPublished - 18 Oct 2021
EventBatteries Event 2021 - Lyon, France
Duration: 18 Oct 202120 Oct 2021


ConferenceBatteries Event 2021

ASJC Scopus subject areas

  • Automotive Engineering

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