Battery systems

Lectures

Flexible, fast and transparent approaches to battery capacity forecasting

Battery degradation is a complex phenomenon, leading many to use data-driven techniques to predict future battery health [1]. Linear models are transparent, easy to implement and not computationally demanding. However, simple linear models are often combined with Kalman filters and particle filters when modelling battery degradation [1]. The need for

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Controlling module pressure evolution over lifetime with buffer layers: Design guidelines, prediction and validation for automotive systems

The development of cheap, energy dense lithium-ion battery systems for electric vehicles is pushed with enormous effort. Stacking pouch-type cells in modules achieves the highest energy densities. As a consequence, however, such modules require an outer bracing to provide a medium pressure environment for optimal cell operation in terms of

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Posters

Thermal conductivity characterization considering dependencies on battery states with implication for thermal modeling and management

Extreme fast charging lithium-ion batteries require aggressive thermal management. High heat generation has to be compensated with active cooling to keep the cell temperature below hazardous thresholds. The importance of thermal management is further increased for many new cell designs. Improvements in energy density often bring along weaker thermal performance.

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Temperature impact on the current distribution in Li-ion cells

The behaviour of lithium-ion cells strongly depends on their internal temperature. Thereby, a higher temperature enhances the transport processes. An inhomogeneous temperature distri¬bution within the cell thus leads to an inhomogeneous current distribution with higher current densities in the warmer regions of the cell due to the lower resistances. As

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State estimation for fast charging applications of lithium-ion batteries

The use of reduced-order electrochemical models creates opportunities for battery management systems to control the battery behavior by monitoring the internal states in electrochemical processes, which are critical for safety enhancement and degradation mitigation. This poster explores a state observer for lithium-ion batteries based on an extended single-particle model, which

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Replication of the thermal behaviour of lithium-ion cells with substitute cells

The performance as well as the lifetime of lithium-ion battery cells are strongly temperature-dependent. To achieve optimal results in both aspects, efficient thermal management systems are needed in the automotive application. Along the development process of these systems, manufacturers face certain obstacles considering the validation of battery systems. An extensive

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Model-based characterization for silicon-carbon blended electrodes

In recent research for the design of better performing lithium-ion batteries, blended electrodes have started gaining relevance, combining beneficial characteristics of different materials. As an example, silicon graphite anodes are good candidates to increase the energy density of lithium-ion batteries. The complexity of transport phenomena increases in blended electrodes and

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High-Voltage-Safe Digital Temperature Measuring System for the Verification and Characterization of HV Batteries

Batteries are of central importance to electric vehicles. Their temperature behavior has to be investigated precisely and temperature models have to be verified. For the development of suitable temperature management systems, the thermal behavior of all components within the battery housing must be known. The thermal characterization of high-voltage batteries

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Evolution of Mobility

As electric mobility is increasingly shaping our daily mobility, it is also starting to conquer special vehicle applications. Although technology, design and manufacturing of battery systems are despite the system complexity well understood, it remains a challenge to have fitting solutions for this wide range of applications. Especially while the

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Diagnosis of Battery Condition Using Ultrasonic Measurements

In lithium-ion batteries (LIBs), mechanical alteration of the composites can cause a safety-critical state during battery operation. These alterations can be caused by deformation, inhomogeneous straining, or lithium plating just to name a few. Besides a safety risk, such alterations can lead to a massive loss of capacity, accelerate the

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Challenges and solutions in battery system prototyping

Within the framework of the research project „Lebenszykluskostenreduktion im elektrischen Verteilerverkehr durch individuell adaptierbaren Antriebsstrang“ (LiVe), modular battery systems for commercial vehicles are being developed at the PEM of the RWTH Aachen University. Based on the proclaimed project objective of optimizing life cycle costs, different core requirements for battery system

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Anode-Controlled Fast Charging Optimization of Lithium Ion Batteries

Electric vehicles are an important element for a sustainable environmentally and climate-friendly mobility. But charging of these takes considerably more time than refueling of a conventional one. This can be an obstacle for many consumers. For an increased acceptance of electric vehicles, the general objective is to charge the battery

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Analysis of isotope labeled lithium-ion battery electrolytes – tracing solvent molecule decomposition during first cycles

The instability of state-of-the-art lithium-ion battery (LIB) electrolytes against applied electrode potentials results in redox reactions at the electrode/electrolyte interfaces. Especially during the first charge and discharge cycles, the solid electrolyte interphase (SEI) is formed on the negative electrode caused by solvent molecule and conducting salt decomposition. A sufficient interphase

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Analysis of Impedance Spectra of Aged Commercial LTO Cells

The impedance spectra of aged commercial LTO cells have been fitted with an equivalent circuit model. The model contains an inductive part, a constant phase element and resistance for the charge transfer process and a Warburg element and addition RC-element for the slower frequency tail. The serial resistance, charge transfer

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A comparative study of impedance based modelling of lithium-ion batteries on half and full cell level

The dynamic performance of lithium-ion cells is strongly dependent of the underlying loss processes such as contact resistances, charge transfer and ion diffusion. Electrochemical impedance spectroscopy (EIS) is a well-known characterisation method for quantifying the complex impedance of electrochemical systems such as lithium-ion cells. In combination with an equivalent circuit

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