Alexander Warnecke

HELLA Group | HELLA · Department of Electronics

As an alternative battery technology to the established lithium-ion battery, the lithium–sulfur battery shows great potential due to its greater energy density, safety and possible lower material costs. In the next few years 500-600Whkg⁻¹ could be implemented. However, there are still challenges in the commercialization and condition monitoring of...

The lithium-sulfur battery belongs to the group of promising technologies known as post lithium-ion batteries, due to its high specific capacity of 1672Ahkg−1, specific energy density of around 2600Whkg−1 and the expected low price. Due to low performance, capacity fading and low coulombic efficiency, the commercialization is slow. The complex mech...

We describe the design process of deep learning models trimmed towards runtime and detection performance for road damage detection using front-facing camera sensors of conventional vehicles. We distinguish between deep learning tools that improve detection performance while suffering on runtime ('Bag of Investments') and those that will enhance det...

Globally rising emissions are considered one of the main reasons for the climate change we face today. In this context, the electrification of vehicles represents an important contribution to fulfil these targets. The key component of the powertrain is the battery system. Lithium-ion batteries are the first choice today but are limited in their spe...

As one of the next generations of lithium-ion technology, the lithium-sulfur battery is considered a promising rechargeable energy system. Compared to the current lithium-ion technology, the lithium-sulfur battery has advantages such as high energy density as well as reducing the usage of rare earths such as nickel, manganese or cobalt because abun...

The lithium-sulfur (LiS) battery has been gaining more attention in research and industry in the last decade as successor of lithium-ion batteries. The advantages of the LiS battery can be attributed to the high theoretical energy density 2600 Wh/kg and abundant occurrence of the low-priced sulfur. In practice, LiS systems presented energy densitie...

To reduce the carbon dioxide (CO2) emissions, the powertrain of the vehicle will be electrified. Furthermore, the electrification of utility vehicles, like long-distance vehicles, will play in future a significant role in achieving the world’s CO2 targets. In this context, the battery plays a key role in the electrification of the powertrain. Lithi...

Lead-acid batteries are still the cash cow in the market of energy storage systems. Use in vehicles will continue in the next years due to several advantages over competing products. Despite the high level of maturity of Lead-Acid Batteries (LABs), the Lead-Acid Battery (LAB) is with 40 % by far the largest cause of short-term vehicle breakdowns. T...

Information about road damages are of great interest for federal road authorities and their infrastructure management as well as the automated driving task and thus safety and comfort of vehicle occupants. Therefore, the investigation of the automatic detection of different types of road damages by images from a front-facing camera in the vehicle i...

In recent years, automated driving has become one of the most important research fields in the automotive industry. A key component for a successful substitution of human driving by vehicles is a real-time model of the current environment including the traffic situation, the guide-way, and the road itself. We propose a solution for measuring road c...

In the past years, automated driving has become one of the most important research fields in the automotive industry. A key component for a successful substitution of human driving by vehicles is a real-time model of the current environment including the traffic situation, the guide-way, and the road itself. Although, most of the information for th...

In this paper, a real-time signal processing frame-work based on a 60 GHz frequency-modulated continuous wave (FMCW) radar system to recognize gestures is proposed. In order to improve the robustness of the radar-based gesture recognition system, the proposed framework extracts a comprehensive hand profile, including range, Doppler, azimuth and ele...

In this paper, a real-time signal processing framework based on a 60 GHz frequency-modulated continuous wave (FMCW) radar system to recognize gestures is proposed. In order to improve the robustness of the radar-based gesture recognition system, the proposed framework extracts a comprehensive hand profile, including range, Doppler, azimuth and elev...

In this paper, a multi-feature encoder for gesture recognition based on a 60 GHz frequency-modulated continuous wave (FMCW) radar system is proposed to extract the gesture characteristics, i.e., range, Doppler, azimuth and elevation, from the low-level raw data. The radar system updates the hand information for every measurement-cycle on all the sc...

The non-invasive investigation of lithium-ion batteries is of great importance, e.g. for improvement of electrode materials or monitoring the state of health (SOH) in stationary or mobile applications. Electrochemical impedance spectroscopy (EIS) is a powerful tool for this task. Once the predominant processes in the impedance spectra are assigned...

Within this work a method is presented that is a powerful tool to characterize the calendaric aging induced rate of capacity fade and enables to present the Arrhenius relation with a high resolution in a simple test arrangement. This method may be a fast and cheap alternative to state-of-the-art calendaric aging tests. The results have been already...

Sudden increase □ Capacity loss □ Resistance increase ■ CL on top of the anode □ Several µm thick □ Dendritic structures □ Consists of high fraction of Li and SEI products (EDX and SEI) ■ Slow Li plating on front side ■ Electric insulation of plated Li and subsequent passivation (SEI) ■ Evolution of µm thick CL ■ Pressure increases on back side ■ F...

Influence of the anode overhang and the homogeneity of lithium distribution (HLD) on capacity fade to determine the actual irreversible aging

Reusing electric vehicle batteries once they have been retired from the automotive application is stated as one of the possible solutions to reduce electric vehicle costs. Many publications in literature have analysed the economic viability of such a solution, and some car manufacturers have recently started running several projects to demonstrate...

During cyclic aging of lithium-ion batteries the formation of a µm-thick covering layer on top of the anode facing the separator is found on top of the anode. In this work several post-mortem analyses of cyclic aged cylindrical LFP|Graphite cells are evaluated to give a detailed characterization of the covering layer and to find possible causes for...

In this work a parametrization approach as well as the modelling of a physico-chemical impedance model are explained. Furthermore relaxation behavior on the full-cell and the half-cells are shown. Finally the validation of the parametrized model is presented. The main relaxation effect in the full-cell is caused by different graphite plateaus and i...

In this work the differential voltage analysis (DVA) is evaluated for LiFePO 4 |Graphite cylindrical cells aged in calendaric and cyclic tests. The homogeneity of the active lithium distribution and the loss of anode active material (LAAM) are measured by the characteristic shape and peaks of the DVA. The results from this analysis exhibit an incre...

Modelling of batteries has become an important part in the design process of battery application. Especially for electric vehicles the design options can become very complex. To be able to make better design decisions, powerful modelling tools are necessary. However, one of the major drawbacks of complex models is the additional effort that is need...

In this contribution a simple in-situ method named capacity difference analysis (CDA) is introduced to characterize lateral flow of lithium-ions within the anode. Therefore, simply the difference between two capacity measurements, which are determined at significantly different current rates, are evaluated for each check-up. During aging the initia...

The evaluation of floating currents is a powerful method to characterize capacity fade induced by calendaric aging and enables a highly resolved representation of the Arrhenius relation. The test arrangement is simple and could constitute a cheap alternative to state-of-the-art calendaric aging tests including checkup tests. Therefore the currents...

The evaluation of floating currents is a powerful method to characterize capacity fade induced by calendaric aging and enables a highly resolved representation of the Arrhenius relation. The test arrangement is simple and could constitute a cheap alternative to state-ofthe- art calendaric aging tests including check-up tests. Therefore the currents...

Basic definitions of efficiency of battery cells and battery systems incl. power electronics are presented. Data on efficiency measurements on lithium-ion battery cells, lead-acid starter batteries and supercaps as a function of temperature, age and current rate are presented. In addition efficiency curves for Inverters in small and large scale sta...

Reusing electric vehicle batteries once they have been retired from the automotive application is stated as one of the possible solutions to reduce electric vehicle costs. Many publications in the literature have analyzed the economic viability of such a solution, and some car manufacturers have recently started running several projects to demonstr...

2016 the lithium-ion battery is commercially available for 25 years and has improved since the marked entrance drastically. This shows that a lot of effort was put into research finding new materials for longer lifetime, higher energy density and power capability. This results in a high diversity of electrode materials so there is not only one comb...

The European Project “Batteries 2020” unites nine partners jointly working on research and the development of competitive European automotive batteries. The project aims at increasing both the energy density and lifetime of large format pouch lithium-ion batteries towards the goals targeted for automotive batteries (250 Wh/kg at cell level, over 40...

The parameterization of a physico-chemical model constitutes a critical part in model development. Conclusions about the internal state of a battery can only be drawn if a correct set ofmaterial parameters is provided for thematerial combination under consideration. In this work, parameters to fully parameterize a physico-chemical model for a 7.5 A...

Electric mobility is a growing sector and already nowadays one of the driving forces in the development of cheap, powerful, long lasting and safe lithium-ion batteries. Due to the variability of the lithium-ion technology not only one combination of cathodes and anodes is possible and used. A very promising combination for electric vehicles seems t...

The Integrated Project “Batteries 2020” unites 9 European partners jointly working on the research and development of European competitive automotive batteries. The project aims at increasing lifetime and energy density of large format high-energy lithium-ion batteries towards the goals targeted for automotive batteries. Three parallel strategies w...

Electric mobility is a growing sector and already nowadays one of the driving forces in the development of cheap, powerful, long lasting and safe lithium-ion batteries. Due to the variability of the lithium-ion technology not only one combination of cathodes and anodes is possible and used. A very promising combination for electric vehicles seems t...

An extensive set of accelerated aging tests has been carried out employing a Li-ion high energy 18650 system (2.05 Ah), negative electrode: carbon, positive electrode: Li(NiMnCo)O2). It is manufactured by Sanyo, labeled UR18650E, and is a commercial off-the-shelf product. The tests comprise both calendar life tests at different ambient temperatures...