Impact of the Level of Homogenization in 3D Thermal Simulation on the Internal Temperature Distribution of Li‐Ion Battery Cells

Queisser, Oliver; Cloos, Lisa; Boehm, Friederike; Oehler, Dieter; Wetzel, Thomas

doi:10.1002/ente.202000915

Cited by 5 publications

(5 citation statements)

References 24 publications

(42 reference statements)

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“…The cells, that were originally at a lower temperature and changed to a higher temperature at the beginning of charge, showed the strongest depositions in the center of the jelly roll, in the center of the sheet. This is exactly where cells are known to increase in temperature due the interplay of heat generation and limited conduction [41] . Especially, if the temperature is low, the heat generation will be high due to higher irreversible losses caused by increased resistances [42] …”

Section: Discussionmentioning

confidence: 99%

“…This is exactly where cells are known to increase in temperature due the interplay of heat generation and limited conduction. [41] Especially, if the temperature is low, the heat generation will be high due to higher irreversible losses caused by increased resistances. [42] Further, the cell that started charging at a higher temperature and changed to a lower one, showed depositions mostly in the bends of the jelly roll and at the electrode edge opposing the tabs.…”

Section: Anode Peak Flatmentioning

confidence: 99%

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Thermal Transients to Accelerate Cyclic Aging of Lithium‐Ion Batteries

Cloos,

Queisser,

Chahbaz

et al. 2023

Batteries & Supercaps

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Cyclic aging tests of lithium‐ion batteries are very time‐consuming. Therefore, it is necessary to reduce the testing time by tightening the testing conditions. However, the acceleration with this approach is limited without altering the aging mechanisms. In this paper, we investigate whether and how thermal transients accelerate the aging. The tests are performed on NMC/graphite pouch cells by applying temperatures in a range of 5 °C to 45 °C to the cell surface. The results show, that an accelerated capacity loss can be achieved in comparison to the reference cell at a steady‐state temperature of 25 °C. However, capacity difference analysis (CDA) prognoses a covering layer for the transient cells, which is confirmed upon post‐mortem analysis. We suspect the origin to lie in the dynamics of temperature fields and current distribution during temperature changes when charging. More specifically, areas of higher temperature in the cell lead to high local current densities and plating. Subsequently, high temperatures promote the reaction of the plated lithium with electrolyte. The results show that thermal transients are a critical condition for lifetime and safety and should be treated with caution as they can occur during real life operation.

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Section: Discussionmentioning

confidence: 99%

Section: Anode Peak Flatmentioning

confidence: 99%

Thermal Transients to Accelerate Cyclic Aging of Lithium‐Ion Batteries

Cloos,

Queisser,

Chahbaz

et al. 2023

Batteries & Supercaps

Self Cite

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“…This is why the parameterization of the thermal model is conducted individually for all the five arrangements obtained during the space-filling step, leading to a cell typespecific and thickness-dependent parameterization of the model concerning the thermal material properties. Mean values of the density and specific heat capacity of the cell stack are calculated following a volumetric and mass-specific averaging, respectively [34]. Regarding the effective thermal conductivity of the battery stack, it is distinguished between the in-plane thermal conductivity and through-plane thermal conductivity, which are calculated from a parallel and series connection of the single components, respectively [35].…”

Section: Thermal Design and Dimensioning Of The Coolingmentioning

confidence: 99%

Methodology for the Holistic Design of Format-Flexible Lithium-Ion Battery Systems

Gandert,

Mühlpfort,

Müller-Welt

et al. 2024

International Journal of Energy Research

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Most battery cells are developed according to a standard design and optimized regarding their electrical properties. However, firstly, there is a demand for an individual cell design adapted to the application. Secondly, additional properties, for example, thermal and mechanical, are decisive for the cell behavior and should be considered in the overall design. Therefore, the present work introduces a model-based development tool for the holistic design of format-flexible battery cells, which are optimized for their future application, allowing for different cell geometries within one battery system. The different approaches and simulation models for the single design steps are presented, and the prediction of the electrochemical, electrical, and thermal behaviors of the cell and whole battery system is described. A key aspect here is the appropriate interconnection of the single models in a way that helps to narrow down the multitude of interacting parameters in a systematic manner and, thus, makes a holistic design possible. In a last step, the functionality of the tool is shown in a case study by means of an e-bike battery pack.

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“…Further model simplification includes the utilization of symmetries and dimensionality reduction of critical system properties [36]. Additionally, homogenization of heterogenous domains and properties is widely used [37].…”

Section: Numerical Setupmentioning

confidence: 99%

Influence of Adhesive Tapes as Thermal Interface Materials on the Thermal Load of a Compact Electrical Machine

Graichen

Sauerhering

Stamann

et al. 2022

WEVJ

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In this article, a novel form of thermal interface material (TIM), represented by three industrially manufactured pressure-sensitive adhesive (PSA) tapes with electrical insulating properties, is characterized regarding its applicability in an electric motor with air-gap winding. Firstly, the adhesion performances, in terms of the winding process, were investigated experimentally. Here, every TIM shows sufficient shear strength for the wire–TIM joints, as well as peel adhesion to the laminated iron core. Secondly, the thermal–physical properties of the TIMs are inspected experimentally via laser flash analysis (LFA) and differential scanning calorimetry (DSC). For every TIM, the value of the thermal resistance can double if the relatively smooth surface (Ra = 0.2 μm) of the adjacent layers is interchanged with a rougher one (Ra = 2.0–3.7 μm). Additionally, the TIM’s performance at the system level is examined. Therefore, a flat test section, according to the specifications of the original motor, is studied experimentally and numerically utilizing infrared (IR) thermography and the finite element method (FEM). The focus is set on the heat flow and temperature distribution in the test section under varying thermal loads, mass flow, and variety of TIMs.

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Impact of the Level of Homogenization in 3D Thermal Simulation on the Internal Temperature Distribution of Li‐Ion Battery Cells

Cited by 5 publications

References 24 publications

Thermal Transients to Accelerate Cyclic Aging of Lithium‐Ion Batteries

Thermal Transients to Accelerate Cyclic Aging of Lithium‐Ion Batteries

Methodology for the Holistic Design of Format-Flexible Lithium-Ion Battery Systems

Influence of Adhesive Tapes as Thermal Interface Materials on the Thermal Load of a Compact Electrical Machine

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