Open Access

Ensuring the safety of electrochemical energy storage systems is a key challenge for the large-scale deployment of batteries in the energy transition. Incidents involving lithium battery fires have increased public and regulatory attention to battery safety, particularly for high-energy systems. A major safety concern is thermal runaway (TR), a critical failure process that can lead to rapid self-heating, the release of toxic and flammable gases, and ultimately fire and toxic gases. Solid-state batteries (SSBs) are widely considered a promising pathway to improve battery safety by replacing flammable liquid electrolytes with solid materials. While some SSB concepts still use polymer or hybrid electrolytes, all-solid-state batteries (ASSBs) rely entirely on solid components such as ceramic electrolytes and are therefore often expected to suppress classical TR mechanisms. However, experimental data enabling a comprehensive safety assessment of ASSBs remain limited. This work systematically investigates failure scenarios in liquid, semi-solid, and all-solid battery systems using electrical, mechanical, and thermal abuse methods. The resulting failure characteristics and safety-relevant mechanisms are compared providing new insights into the safety behavior of solid-state battery technologies.

Der Vortrag gibt einen kompakten, fachlich fundierten Überblick über aktuelle Entwicklungen in der Batterie-Sicherheit mit Schwerpunkt auf Lithium- und Natrium-Ionen-Batterien. Im Zentrum stehen deren sicherheitstechnische Bewertung als Gefahrgut, die Risiken des thermischen Durchgehens sowie die Bedeutung von Zellchemie, Ladezustand und Propagationsverhalten für Brand- und Transportgefahren. Darauf aufbauend werden bestehende und künftige Prüf- und Klassifizierungssysteme, insbesondere im Kontext der UN 38.3-Prüfungen und neuer gefahrbasierter Einstufungen, vorgestellt. Ergänzend beleuchtet der Vortrag aktuelle Arbeiten zu Verpackungsanforderungen, beschädigten oder defekten Batterien sowie zu neuen Batterietechnologien wie Natrium-Ionen-, Lithium-Luft- und Festkörperbatterien.

The reuse of lithium-ion batteries (LIBs) from electric vehicles (EVs) in second-life applications such as battery energy storage systems (BESSs) offers significant environmental and economic benefits. Beyond economic considerations, safety management is a key challenge for large-scale deployment, yet the influence of ageing on LIB safety remains insufficiently understood. Preger et al., emphasized in their review the existing gap on data about electrical abuse and high-capacity cells. This laboratory-scale study investigates the evolution of key safety parameters over battery lifetime. The present study contribute to closing this gap studying three types of LIB cells (Nickel Manganese Cobalt (NMC) chemistry) from EV and hybrid EV batteries that were artificially aged and tested at three representative states of health (SOH): 100% (beginning-of-life, BOL), 80% (end of first life), and 60% (midpoint of second life). Cells were subjected to thermal abuse, overcharge, and accelerating rate calorimetry, with selected tests coupled to online gas analysis. Results show a pronounced ageing effect on thermal stability. The onset temperature of thermal runaway was reduced by 17–69 ◦C for aged cells (60% SOH) compared with BOL cells, while overcharge acceptance decreased by 13–78%. Although aged cells exhibited lower thermal stability, their thermal runaway reactions under inert conditions were less severe, as indicated by lower maximum temperatures. These findings highlight the need to account for ageing-induced shifts in exothermic reaction onset and thermal runaway behavior when designing safe second-life BESS. Future work should extend the analysis to LFP chemistries especially as the market is expected to shift towards this chemistry and consider battery and system levels, including influence of ageing on thermal runaway propagation.

The present work demonstrates the application of a multimodal non-contact ultrasonic test technique as diagnostic tool for lithium-ion pouch cells. Different propagation modes of elastic waves (shear and longitudinal), different propagation directions (from normal to the cell plane to in the cell plane), and different wave analysis techniques (including time and frequency domain analysis, and propagation and resonant techniques) are applied. Air-coupled ultrasonic waves with frequencies ranging from 0.15 to 1.4 MHz were used in a through transmission configuration with varying incident angles from 0 to 60◦. As practical example, degradation in lithium-ion pouch was investigated. For this purpose, pristine and two types of altered cells were used. Alterations were induced by two deliberate degradation processes (deep discharge and calendar ageing). The information provided by the proposed multimodal ultrasonic technique is analyzed in combination with structural and electroanalytical data, and the a priori knowledge about the induced alterations to provide a first insight into the capabilities of the proposed technique. While the deep-discharge process introduces minor modifications in the ultrasonic response, the calendar ageing process produces a severe change, most likely, the result of a local and randomly distributed degradation of the mechanical continuity between the different layers (linked to electrodes modification, solid electrolyte interface modification, loss of compactness, appearance of cracks, gas generation, delaminations, etc.). These technologies can find applications in the research of new batteries, for inline quality test in fabrication and for second-life battery sorting.

Recycling existing materials and products as far as possible is an integral part of the circular economy. Plastic-based packaging, including containers for food and beverages but also for storing and transporting chemicals and dangerous goods, are presently made to a wide range from fossil resources. However, even for these “contact sensitive” products, there is still the aim of sustainability using recycled materials. For packings for the transport of dangerous goods, safety characteristics of the containments made from the “virgin” materials including polyethylene (PE) are well known and tested within the frame of their design type approval. Much less, however, is known about their counterparts made from recycled materials. Apart from material weaking, incorporation of residues into recycled plastics can cause contamination of the goods inside the packaging. To fill this gap, we have evaluated high-density PE (HDPE) canisters made from post-consumer waste towards release of plastic additives and contaminants such as residues from former contents. Using a comprehensive untargeted high-resolution mass spectrometry (HRMS) approach as well as thermal extraction-desorption gas chromatography-mass spectrometry (TED-GC/MS), we detected up to 870 distinct components depending on the type of stored chemical and storage duration. Most of the components were unique to or released in significantly higher amounts from recycled HDPE compared to conventional HDPE. 129 of the components could be identified and analyzed for functional use. The analysis revealed “cosmetics”, “fragrance” and “flavoring” as major associations next to known and expected uses in the field of “plastics”, indicating significant introduction of foreign contaminants into the product. We present details on the compound classes involved and discuss consequences for political targets on increasing recycling rates in this product segment.