COMPARATIVE STUDY OF FIRE SAFETY REQUIREMENTS FOR ELECTROCHEMICAL ENERGY STORAGE SYSTEMS IN DOMESTIC AND FOREIGN REGULATIONS

Peering into Batteries: Electrochemical Insight Through In Situ and Operando Methods over Multiple Length Scales

Introduction. Ukraine has large reserves of lithium ores, which makes it possible to attract domestic enterprises and institutions related to the electrochemical field to global cooperation in the creation of energy storage systems. In this context, the purpose of the article was to investigate the prospects for the use of lithium in modern energy storage systems, as well as to assess the domestic scientific potential of creating energy storage systems for renewable energy. Materials and methods. The following methods were used to conduct the research: analysis and synthesis, comparison, monographic, economic-statistical, systemic approach, etc. To assess the prospects of lithium in modern energy storage systems and the potential of domestic science, a review of scientific publications on the topic of the study was made. Results and discussion. A comparison of the best-known energy storage systems today allows us to conclude that electrochemical energy storage systems are the cheapest, most flexible, compact, ecological and efficient. Other energy storage systems occupy their niches, develop technologically and will compete for electrochemical systems. Lithium, as the most energy-intensive metal, plays a key role in electrochemical energy storage systems. Lithium forms the basis of lithium-ion batteries, and is also part of other innovative batteries that may eventually replace lithium-ion batteries. Thus, in the medium term, the demand for lithium is most likely to be stable, which opens up prospects for the domestic lithium industry. Conclusions. Lithium plays a key role in electrochemical energy storage systems due to its high energy density. Currently, the demand for lithium is formed by lithium-ion batteries, which have a large specific weight in electrochemical energy storage systems. But in the future, when the life cycle of lithium-ion batteries will end, the demand for lithium will remain due to its high technical characteristics. Ukraine has sufficient scientific potential for the development of the electrochemical industry. This is evidenced both by the history of the formation of the scientific school of electrochemistry in the institutes of the National Academy of Sciences of Ukraine, and by modern research conducted by Ukrainian scientists in Western universities and in Ukraine.

Transition metal oxides possessing two kinds of metals (denoted as AxB3-xO4, which is generally defined as a spinel structure; A, B = Co, Ni, Zn, Mn, Fe, etc.), with stoichiometric or even non-stoichiometric compositions, have recently attracted great interest in electrochemical energy storage systems (ESSs). The spinel-type transition metal oxides exhibit outstanding electrochemical activity and stability, and thus, they can play a key role in realising cost-effective and environmentally friendly ESSs. Moreover, porous nanoarchitectures can offer a large number of electrochemically active sites and, at the same time, facilitate transport of charge carriers (electrons and ions) during energy storage reactions. In the design of spinel-type transition metal oxides for energy storage applications, therefore, nanostructural engineering is one of the most essential approaches to achieving high electrochemical performance in ESSs. In this perspective, we introduce spinel-type transition metal oxides with various transition metals and present recent research advances in material design of spinel-type transition metal oxides with tunable architectures (shape, porosity, and size) and compositions on the micro- and nano-scale. Furthermore, their technological applications as electrode materials for next-generation ESSs, including metal-air batteries, lithium-ion batteries, and supercapacitors, are discussed.

Reliable fault detection is essential for ensuring the safe and efficient operation of electrochemical energy storage systems, including lithium-ion batteries and transformer. However, the performance of machine learning-based fault diagnosis models is often degraded in practice due to label noise in training data, caused by sensor inaccuracies, ambiguous fault transitions, and imperfect labeling processes. This paper proposes a lightweight and effective kernel-based data rectification framework to improve the robustness of fault detection under noisy label conditions. The method identifies and discards low-density data points that are statistically more likely to be mislabeled, using kernel density estimation and a tunable data discarding strategy. The approach is computationally efficient, classifier-agnostic, and easily applicable to existing fault diagnosis pipelines. We evaluate the proposed method on two datasets: simulated lithium-ion battery voltage data under various fault scenarios, and transformer winding oscillation wave data under multiple winding fault conditions. The results demonstrate that the rectification framework significantly improves classification accuracy across both Support Vector Machine (SVM) and Extreme Learning Machine (ELM) classifiers. Furthermore, the choice of discarding ratio is shown to be critical, with optimal performance achieved when the ratio is tuned close to the underlying noise level. These results highlight the potential of the proposed method to enhance the reliability of fault diagnosis in electrochemical energy storage systems. Future work will explore adaptive strategies to automatically optimize the rectification strength without requiring prior knowledge of the noise rate, and extend the framework to multi-sensor and multi-modal monitoring scenarios.

Fire and explosion characteristics of vent gas from lithium-ion batteries after thermal runaway: A comparative study

The development and innovation of new electrode materials is needed for the next generation of electrochemical energy storage systems (EES). Lithium-ion batteries (LIB) are the leading technology in EES, however, they are plagued with several limitations including safety and stability. Metal oxide electrodes could provide a safer battery while maintaining high reversible capacity. When compared to the commonly used graphite, metal oxides operate at voltages above that of Li plating for safe operation. In addition, nanostructured metal oxides could enhance the performance of the battery by facilitating fast electron and ion transport. Traditionally, intercalation compounds of well-ordered close-packed oxides have been prized because of the general consensus that well-ordered structures having little or no intermixing between Li and transition metal sublattice are required to achieving high capacity with good stability. Consequently, disordered materials have received limited attention and have been less studied. Nevertheless, in recent years evidence has shown that transition metal oxides which have structural defects (e.g., vacancies and interstitials) at cation sites with local disorder have the potential to offer higher capacity and better stability compared to ordered oxides. In this talk, we report our integrated experimental and computational study of a nanostructured amorphous niobium oxide electrode for lithium ion battery. An irreversible phase transformation from amorphous to crystalline phase in niobium oxide electrode is observed during the first discharging process. The newly formed crystalline niobium oxide electrode exhibits high capacity, superb rate capability and good cycle life. The electrochemical charge storage mechanisms of the new electrode will be discussed.

Optimization of technical and economic parameters of electric power storage devices is a necessary condition for their widespread use. The article develops a general approach and proposes a methodology for assessing the economic efficiency of hybridization of electrochemical energy storage systems (ESSs). From the point of view of evaluating the effectiveness of storage hybridization, a number of model systems operating under different load conditions using different block functional interaction schemes are being investigated. Lead-acid batteries supplemented with lithium-ion batteries; lead-acid batteries supplemented with supercapacitors and lithium-ion batteries supplemented with supercapacitors are considered as the basic types of hybrid storage devices. An electric forklift, a 30-apartment residential building, as well as a 300-apartment residential complex are considered as the load of the ESS. A quantitative and qualitative model for evaluating the effectiveness of hybridization is used, based on comparing the cost of buffering electricity by each type of battery and the hybrid drive as a whole. For all cases, economic indicators characterizing the cost of buffering electricity by hybrid ESSs are calculated and the advantages of a particular scheme of interaction of hybrid ESS blocks are analyzed. It is shown that the hybridization efficiency demonstrates a complex nonlinear dependence on the degree of hybridization, the type of which depends both on the type of batteries used and on the nature of the load schedule, as well as on the type of functional interaction of the blocks. A specific feature of this dependence is a sharp increase in economic efficiency at small values of a £ 0.01 and a further slowdown in the growth or fall of the graph. The obtained results make it possible to quantitatively compare the efficiency of the hybridization of the ESS for specific conditions of its operation. The considered models and methods can be used in the design of ESSs and “generator – storage – consumer” systems, assessment of the economic feasibility of hybridization of ESSs.

Suitability of representative electrochemical energy storage technologies for ramp-rate control of photovoltaic power

The article raised the question of the formation and development of the system of categorization of premises and buildings of industrial and warehouse use on fire and explosion hazards. The role of this system in the development of regulatory requirements for fire safety is noted. It is shown that, despite more than 75 years history improve the criteria and methods for determining the category currently contentious issues still are remained, and ambiguous interpretation of certain provisions of Set of rules 12.13130.2009 is allowed. With the entry into force of the Federal law No. 123 Technical regulations about requirements of fire safety and the introduction of such a criterion of fire safety of objects of protection as the value of the individual fire risk the current system of categorization has become largely obsolete. Methods for determining the categories of premises and determine the design value of the fire risk, pursuing, in general, a single objective-to assess the level of fire hazard protection object and define the list of requirements of fire safety, sometimes give a different result that calls into question efficiency of a lot of positions of normative documents on fire safety. Consideration of these requirements through the prism of ensuring the standard value of fire risk, questioned the objectivity of the existing criteria categorization, as a tool to measure the level of threat to life and health of people in the building. The article presents examples that demonstrate that the categories of premises or buildings on the fire and explosion hazards often do not allow to assess the real fire hazard of production.

R. Brady Williamson (1933–2007) Professor R. Brady Williamson passed away on 1 August 2007, after battling cancer for several years. He was born on 19 November 1933, studied at Harvard University, obtained his bachelor degree in physics, then a doctorate degree in applied physics in 1965. He was appointed to the faculty of MIT, and in 1968 he received a joint appointment to the Civil Engineering and Material Science departments at the University of California, Berkeley. His graduate work was on the morphology of ice crystals, and he performed significant research in Materials Science at MIT in metallurgy, polymers, and cementitious materials. When he came to UCB, his interests changed profoundly. UCB previously had two professors, Raymond E. Davis and G. Earl Troxell, who had focused on fire resistance research and built fire resistance testing facilities, primarily for use as a service to industry. Williamson took over the testing facility from Troxell and dramatically expanded the scope of fire research at UCB. Apart from his work in fire resistance (one of us, V. B., was his first PhD student and did his dissertation on that subject), Prof. Williamson will perhaps be most remembered for two other contributions: characterizing the fire hazards of plastics and helping establish fire safety engineering science education as a recognized branch of science. In doing so, as evidenced by his publications, the research he directed, and especially with his advising of students, he drew upon a diverse group of disciplines, including, architecture, systems analysis, materials science, wood and polymer science, and many other engineering fields. During this time Prof. Williamson also reached out to a diverse group outside the university, including regulators, public and private sector fire investigators, insurance industry personnel and attorneys, and the fire services. He regularly brought local fire service personnel to observe fire research in the Richmond Field Station laboratory to demonstrate how fire tests are conducted and to make the connection between fire testing and the performance of building assemblies in actual fires. His focus on relating fire-test performance to real-world events was even stronger when it involved his graduate students, who were each given a unique educational experience in relating fire tests to the behavior of real fires. In the early 1970s, the US National Science Foundation first established the RANN program—Research Applied to National Needs—to encourage the use of science and engineering research to address important problems that were national in scope. This was in sharp contrast to the previous focus at NSF, which had been solely on fundamental science. A specialty area for fire research was set up by RANN in response to dismal fire safety statistics in the U.S. A number of universities initiated NSF-funded research in the area, with the largest of these research groups being at UCB. The UCB research group was organized by Prof. Williamson and featured, at its peak, close to a dozen professors from various engineering disciplines and architecture, had numerous graduate students, and became a fertile ground for fostering new fire safety researchers. In the years since the mid-1970s, more scholars have obtained PhD degrees in fire-related subjects from UC Berkeley than from any other university. Although UCB never had a formal department for teaching fire safety science and engineering, its influence on this field has been enormous, and much of it was due to Prof. Williamson's leadership and vision. Prior to Prof. Williamson's research, there had not been a concerted recognition of the potential fire hazards of plastics—especially foam plastics—when used inappropriately. Williamson studied these hazards by developing a room-sized ‘corner test’, which allowed a highly graphical representation of fire safety—or lack thereof—to be demonstrated. Largely because of this research, the U.S. building codes banned the use of foams as a building insulation material, except where testing indicated that the material was indeed safe for the intended purpose. Williamson's focus on abuses of ‘standard’ test methods led to his discovery that some fire tests were potentially highly misleading and their use in evaluating safety could lead to serious fire hazards. The most extreme example was the ASTM D 1692 test, which provided florid ‘self-extinguishing’ and ‘slow burning’ designations for plastics which, in actual fact, burned fiercely in their end-use environment. The US Federal Trade Commission investigated this test and several other test methods and brought actions against 26 plastics manufacturers, American Society for Testing and Materials, and The Society of the Plastics Industry, Inc. in 1973. Prof. Williamson served as FTC's technical consultant in this matter and was pivotal in establishing a settlement with the plastics industry. The settlement, in addition to eliminating misleading test methods, also fostered fire safety science research because one of its terms was that the industry would fund what became known as the Products Research Committee. This ad hoc entity, which existed during the period 1974–1979, funded several dozen industry associates to do research at the National Bureau of Standards (now, NIST) and also funded several dozen research projects on plastics hazards at various research institutions and universities. When added to the existing NSF and NIST programs, the PRC work helped make the late-1970s the high-water mark of concerted fire safety science research in the U.S., a level that has not subsequently been exceeded. For this, we can thank Brady Williamson. Williamson became Professor Emeritus and a Professor in the Graduate school at Berkeley in 2001, and he remained an active and enthusiastic researcher and fire safety consultant until his death. He is survived by his wife Dr Nancy J. Brown Williamson, a well-known atmospheric sciences and combustion researcher, and five children. Brady will be fondly remembered by the numerous fire researchers who have interacted with him and found him a source of inspiration. Indeed, he was a rare professor whose most outstanding contribution was conveying to his students a boundless enthusiasm for fire safety engineering science and a deep conviction in the importance of this field as a true branch of science. ‘Outside the box’ is a perhaps over-used term, but Brady always encouraged his students and colleagues to work outside the box when solving problems and the results were invariably interesting, sometimes thrilling, and always worthy of serious consideration. Surprising though it may be to some of our younger colleagues, prior to the 1970s, when the activities described above took place, there was little appreciation of fire safety as a field worthy of consideration as a true scientific discipline. Fire protection engineering had already existed for many decades, but its focus was almost exclusively on the application of codes and standards, with little interest in research or scientific underpinnings. Prof. Williamson along with the late Prof. Howard Emmons were the two most prominent advocates for science in the fire safety profession, leading to today's situation, where fire safety science and fire protection engineering overlap significantly and fire protection engineering practitioners practice a discipline that has become greatly more science based.

The growing demand for advanced electrochemical energy storage systems (EESSs) with high energy densities for electric vehicles and portable electronics is driving the electrode revolution, in which the development of high-mass-loading electrodes (HMLEs) is a promising route to improve the energy density of batteries packed in limited spaces through the optimal enlargement of active material loading ratios and reduction of inactive component ratios in overall cell devices. However, HMLEs face significant challenges including inferior charge kinetics, poor electrode structural stability, and complex and expensive production processes. Based on this, this review will provide a comprehensive summary of HMLEs, beginning with a basic presentation of factors influencing HMLE electrochemical properties, the understanding of which can guide optimal HMLE designs. Rational strategies to improve the electrochemical performance of HMLEs accompanied by corresponding advantages and bottlenecks are subsequently discussed in terms of various factors ranging from inactive component modification to active material design to structural engineering at the electrode scale. This review will also present the recent progress and approaches of HMLEs applied in various EESSs, including advanced secondary batteries (lithium-/sodium-/potassium-/aluminum-/calcium-ion batteries, lithium metal anodes, lithium-sulfur batteries, lithium-air batteries, zinc batteries, magnesium batteries) and supercapacitors. Finally, this review will examine the challenges and prospects of HMLE commercialization with a focus on thermal safety, performance evaluation, advanced characterization, and production cost assessment to guide future development.

Introduction. Due to the increasing popularity of timber housing construction, new timber structures with unstudied properties appear provided with no fire safety standards of their use.Aim: to obtain data on fire resistance and fire hazard of combined metal-timber structures, used in floors of residential and public buildings.Materials and methods. In the study, a fragment of a combined metal-timber floor structure with a size of 4300 × 2000 mm and a thickness of 160 mm was tested using the methods for determining fire resistance and fire hazard classes.Results. According to the test results, uncoated samples under a vertical uniformly distributed load of 520 kg/m2 were classified as REI 60, while the Evrika fire retardant, applied to samples from the outside at a consumption of 500 g/m2, has improved their fire resistance to REI 90. The fire hazard class of uncoated samples and coated with fire retardants corresponds to K3(15) and K0(15), respectively.Conclusion. New experimental data will be used in the preparation of amendments to SP 64.13330.2017 “SNiP II-25-80 Timber Structures” for ensuring regulatory fire safety requirements to these structures.

With the extensive use of lithium-ion batteries (LIBs) in electrochemical energy storage systems and electric vehicles, their safety concerns have gradually emerged. Once LIBs undergo thermal runaway (TR), they can potentially trigger fire and explosion accidents, presenting substantial safety hazards. Regarding the issue that LIBs may experience TR due to external fires or other high-temperature conditions, the study of their thermal runaway tolerance characteristics under different degrees of external thermal radiation triggering conditions is of great significance in guiding the safe design and operation of LIB systems. Tests on lithium iron phosphate (LFP) and nickel manganese cobalt (NCM) batteries under the influence of different degrees of thermal radiation were conducted to obtain the typical phenomena, thermal radiation tolerance characteristics and tolerance zones of the abovementioned two LIBs after thermal runaway. Experimental results demonstrate that the thermal radiation tolerance thresholds of the NCM batteries and LFP batteries are 1.158 kW m−2 and 1.88 kW m−2, respectively, suggesting that LFP batteries exhibit superior thermal radiation tolerance compared to NCM batteries. Furthermore, prediction models for the duration of external thermal radiation exposure tolerated by NCM and LFP batteries were developed based on the experimental datasets; the models demonstrated a high goodness-of-fit (R2 = 0.96166 and 0.97698, respectively), validating their predictive accuracy. This research can provide guidance for the safety and protection of LIBs under external thermal radiation conditions (such as external fire and direct sun), which is of great significance for their safe operation.

Growing reports of fire incidents originating from lithium‐ion batteries have led to a quest for safer lithium‐ion batteries. Although the commercial success of the lithium‐ion batteries owes a great debt to the liquid electrolyte as much as the electrodes, the liquid electrolyte is considered the most flammable component of the battery. Flame retardant additives offer a promising solution to alleviate electrolyte flammability since they are added in minute quantities. However, the fire resistance and hazard diagnosis of the flame retardant containing liquid electrolyte remains a challenge due to the lack of reliable characterization technology. Herein, a stainless steel sample holder is custom‐designed and integrated into the cone calorimeter, enabling a precise and reliable technique for diagnosing the fire resistance efficiency and hazards of flame retarded liquid electrolytes. This integration allows for real‐time analysis of key fire behavior parameters of the flame retarded electrolytes such as time to ignition, heat release rate, fire growth rate index, smoke toxicity index, carbon monoxide, and smoke produced. Most of the fire test results show high reproducibility with less than 10% error. This study indicates that the modified cone calorimetry is a promising technology for diagnosing flame retarded liquid electrolyte fire resistance and hazard.

Fabrication of transition metal selenides and their applications in energy storage