@article{GeisbauerWoehrlMittmannetal.2020, author = {Geisbauer, Christian and W{\"o}hrl, Katharina and Mittmann, Christoph and Schweiger, Hans-Georg}, title = {Review of Safety Aspects of Calendar Aged Lithium Ion Batteries}, volume = {167}, pages = {090523}, journal = {Journal of the Electrochemical Society}, number = {9}, publisher = {IOP Publishing}, address = {Bristol}, issn = {1945-7111}, doi = {https://doi.org/10.1149/1945-7111/ab89bf}, year = {2020}, abstract = {Nowadays, lithium ion batteries have found their place in a various field of portable applications. With the upcoming of electrically propelled vehicles, it is mandatory to guarantee a safe and predictable behavior during the whole lifetime and not only after manufacturing during performance tests. To gain a general overview of the abuse behavior, research on the topic of abusive tests on calendar-aged cells is being investigated, split up depending on the electrode composition and lined up against each other. It can be shown, that almost all abuse experiments have been performed with external heating tests in the past, still leaving research gaps that need to be filled.}, language = {en} } @article{GeisbauerWoehrlKochetal.2021, author = {Geisbauer, Christian and W{\"o}hrl, Katharina and Koch, Daniel and Wilhelm, Gudrun and Schneider, Gerhard and Schweiger, Hans-Georg}, title = {Comparative Study on the Calendar Aging Behavior of Six Different Lithium-Ion Cell Chemistries in Terms of Parameter Variation}, volume = {14}, pages = {3358}, journal = {Energies}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en14113358}, year = {2021}, abstract = {The degradation of lithium-ion cells is an important aspect, not only for quality management, but also for the customer of the application like, e.g., scooters or electric vehicles. During the lifetime of the system, the overall health on the battery plays a key role in its depreciation. Therefore, it is necessary to monitor the health of the battery during operation, i.e., cycle life, but also during stationary conditions, i.e., calendar aging. In this work, the degradation due to calendar aging is analyzed for six different cell chemistries in terms of capacity degradation and impedance increase and their performance are being compared. In a new proposed metric, the relative deviations between various cells with the exact identical aging history are being analyzed for their degradation effects and their differences, which stands out in comparison to similar research. The capacity loss was found to be most drastic at 60 °C and at higher storage voltages, even for titanate-oxide cells. LiNiMnCoO2 (NMC), LiNiCoAlO2 (NCA) and Li2TiO3 (LTO) cells at 60 °C showed the most drastic capacity decrease. NMC and NCA cells at 60 °C and highest storage voltage did not show any open circuit voltage, as their current interrupt mechanism triggered. The effect of aging shows no uniform impact on the changes in the capacity variance when comparing different aging conditions, with respect to the evaluated standard deviation for all cells. The focus of this work was on the calendar aging effect and may be supplemented in a second study for cyclic aging.}, language = {en} } @article{KotakMarchanteFernandezCanalsCasalsetal.2021, author = {Kotak, Yash and Marchante Fern{\´a}ndez, Carlos and Canals Casals, Lluc and Kotak, Bhavya and Koch, Daniel and Geisbauer, Christian and Trilla, Llu{\´i}s and G{\´o}mez-Nu{\~n}ez, Alberto and Schweiger, Hans-Georg}, title = {End of Electric Vehicle Batteries}, volume = {14}, pages = {2217}, journal = {Energies}, subtitle = {Reuse vs. Recycle}, number = {8}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en14082217}, year = {2021}, abstract = {It is a fact that electric vehicles (EVs) are beneficial for climate protection. However, the current challenge is to decide on whether to reuse an EV battery or to recycle it after its first use. This paper theoretically investigates these areas i.e., recycle and reuse. It was found that there are several commercially used recycling processes and also some are under research to regain maximum possible materials and quantity. The concept of reusing (second life) of the battery is promising because, at the end of the first life, batteries from EVs can be used in several applications such as storing energy generated from renewable sources to support the government grid. However, the cost and life-cycle analysis (LCA) demonstrated that there are several aspects involved in battery reuse applications. Henceforth, one LCA generalised method cannot provide an optimal approach for all cases. It is important to have a detailed study on each of the battery reusing applications. Until then, it is safe to say that reusing the battery is a good option as it would give some time to recycling companies to develop cost and energy-efficient methods.}, language = {en} } @article{WoehrlGeisbauerNebletal.2021, author = {W{\"o}hrl, Katharina and Geisbauer, Christian and Nebl, Christoph and Lott, Susanne and Schweiger, Hans-Georg}, title = {Crashed Electric Vehicle Handling and Recommendations - State of the Art in Germany}, volume = {14}, pages = {1040}, journal = {Energies}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en14041040}, year = {2021}, abstract = {In the near future, electric powered vehicles will represent a major part of the road traffic. Accordingly, there will be a natural increase of accidents involving electric vehicles. There are not many cases of such accidents yet and therefore the experience and correct handling are still partially open points for the involved parties, such as the rescue services for example. The aim of this work is to provide a complete overview of the accident handling sequence in Germany, starting with the damaged vehicle on site and moving on to the risks and challenges for the stakeholders, such as transport and recycling companies. Arising from the developed overview, a handling recommendation for yet undiscussed points is given. Especially, different extinguishing and deactivation methods are compared and discussed. Due to a lack of a common live-feed from battery data on site, other criteria have to be taken into account to assess the state of the battery. The wrecked vehicle—including the high voltage system—needs to be in a definite safe state at the handover to a towing service. Depending on the case, different options for securing the vehicle will be considered in this work.}, language = {en} } @article{WoehrlKotakGeisbaueretal.2023, author = {W{\"o}hrl, Katharina and Kotak, Yash and Geisbauer, Christian and Barra, S{\"o}nke and Wilhelm, Gudrun and Schneider, Gerhard and Schweiger, Hans-Georg}, title = {Analysis of Deactivation of 18,650 Lithium-Ion Cells in CaCl2, Tap Water and Demineralized Water for Different Insertion Times}, volume = {23}, pages = {3901}, journal = {Sensors}, number = {8}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {https://doi.org/10.3390/s23083901}, year = {2023}, abstract = {The deployment of battery-powered electric vehicles in the market has created a naturally increasing need for the safe deactivation and recycling of batteries. Various deactivating methods for lithium-ion cells include electrical discharging or deactivation with liquids. Such methods are also useful for cases where the cell tabs are not accessible. In the literature analyses, different deactivation media are used, but none include the use of calcium chloride (CaCl2) salt. As compared to other media, the major advantage of this salt is that it can capture the highly reactive and hazardous molecules of Hydrofluoric acid. To analyse the actual performance of this salt in terms of practicability and safety, this experimental research aims to compare it against regular Tap Water and Demineralized Water. This will be accomplished by performing nail penetration tests on deactivated cells and comparing their residual energy against each other. Moreover, these three different media and respective cells are analysed after deactivation, i.e., based on conductivity measurements, cell mass, flame photometry, fluoride content, computer tomography and pH value. It was found that the cells deactivated in the CaCl2 solution did not show any signs of Fluoride ions, whereas cells deactivated in TW showed the emergence of Fluoride ions in the 10th week of the insertion. However, with the addition of CaCl2 in TW, the deactivation process > 48 h for TW declines to 0.5-2 h, which could be an optimal solution for real-world situations where deactivating cells at a high pace is essential.}, language = {en} } @article{WilhelmGollaSchindlerWoehrletal.2021, author = {Wilhelm, Gudrun and Golla-Schindler, Ute and W{\"o}hrl, Katharina and Geisbauer, Christian and Cooke, Graham and Bernthaler, Timo and Schneider, Gerhard}, title = {Combined focused ion beam and secondary ion mass spectrometry for high resolution light element detection applied on Li-Ion batteries}, volume = {27}, journal = {Microscopy and Microanalysis}, number = {S1}, publisher = {Cambridge University Press}, address = {New York}, issn = {1431-9276}, doi = {https://doi.org/10.1017/S1431927621003822}, pages = {1012 -- 1015}, year = {2021}, language = {en} } @article{WilhelmGollaSchindlerWoehrletal.2024, author = {Wilhelm, Gudrun and Golla-Schindler, Ute and W{\"o}hrl, Katharina and Geisbauer, Christian and Cooke, Graham and Bernthaler, Timo and Schweiger, Hans-Georg and Schneider, Gerhard}, title = {Influence of Water on Aging Phenomena of Calendric Stored and Cycled Li-Ion Batteries}, volume = {4}, journal = {Nanoenergy Advances}, number = {2}, publisher = {MDPI}, address = {Basel}, issn = {2673-706X}, doi = {https://doi.org/10.3390/nanoenergyadv4020011}, pages = {174 -- 195}, year = {2024}, abstract = {We examine the impact of water (160 ± 41 ppm of reference) on the anode, cathode, separator and electrolyte in two aging scenarios: calendric aging (60 °C, 80 days, charged state), resulting in a triggered current interrupt device (CID), and cycling 1680 times (charge/discharge with 1C, 2.75-4.2 V, 20 ± 2 °C), resulting in 24.5\% residual capacity. We applied computer tomography (CT), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and secondary ion mass spectrometry (SIMS) to understand the capacity loss. The aged NMC/LCO-graphite cells were compared to a reference cell in pristine state. Both aging scenarios showed (a) thick depositions on the anode and cathode consisting mainly of oxygen, fluorine and phosphorous, (b) reduced separator pore sizes, (c) the deposition of Mn, Co and Ni on top of the anode and (d) the decomposition of the conductive salt LiPF6 accompanied by HF formation and a loss of active lithium. Calendric aging consumes the water content and additionally leads to (e) the decomposition of the organic solvent followed by CO2 gas formation. Cyclic aging increases the water content and additionally results in (f) the consumption of the additive fluoroethylene carbonate (FEC). These findings show how water affects aging phenomena and results in a capacity decrease in the cell.}, language = {en} } @article{GeisbauerWoehrlLottetal.2021, author = {Geisbauer, Christian and W{\"o}hrl, Katharina and Lott, Susanne and Nebl, Christoph and Schweiger, Hans-Georg and Goertz, Roland and Kubjatko, Tibor}, title = {Scenarios involving accident-damaged electric vehicles}, volume = {2021}, journal = {Transportation Research Procedia}, number = {55}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2352-1465}, doi = {https://doi.org/10.1016/j.trpro.2021.07.136}, pages = {1484 -- 1489}, year = {2021}, abstract = {Electrically propelled cars will play a major role on the streets, not only in the far, but also in the near future. In this work, an overview on the possible risks arising from electric vehicles is given that involves electrical, chemical and thermal hazards. Additionally, an analysis on different scenarios involving damaged electric vehicles, the involved parties, as well as their risk assessment in terms of hazard rating is presented. Furthermore, two scenarios are explained and addressed with more detail. With the derived risks of the battery and with possible crash scenarios presented, the still existing uncertainties for handling damaged electric vehicles are addressed, followed by a discussion on ways to overcome this problem.}, language = {en} }