Search

Semi-solid lithium slurry battery is an important development direction of lithium battery. It combines the advantages of traditional lithium-ion battery with high energy density and the flexibility and expandability of liquid flow battery, and has unique application advantages in the field of energy storage. In this study, the thermal stability of semi-solid lithium slurry battery material system was investigated for the first time employing C80 micro-calorimeter. In this new electrode material system, the heat generation of the electrolyte is the decisive factor for its thermal stability. Then, the measurement of in-situ dynamic cycle heat generation of semi-solid lithium slurry battery indicated a lower heat generation than traditional lithium-ion battery. What's more commendable is that its electrochemical performance is basically the same as traditional lithium-ion battery. In addition, through the HPPC test, the mechanism of semi-solid lithium slurry battery cycle heat generation was explained. So, in this work, a preliminary evaluation on the safety and cycling stability of semi-solid lithium slurry battery is carried out. The electrochemical performance test affirms the application prospects of semi-solid lithium slurry battery, and the evaluation on the fire safety provides a reference for the future industrial applications of semi-solid lithium slurry battery. [ABSTRACT FROM AUTHOR]

Numerical simulations were conducted to study the dynamics of premixed flames propagating in a closed tube by solving the fully compressible reactive Navier–Stokes equations using a high-order numerical method on a dynamically adapting grid. A simplified chemical-diffusive model was used to describe the reactions and energy release in a stoichiometric hydrogen-air mixture. The influence of wall boundary condition on the flame dynamics was explored by considering three different types of condition on the walls: adiabatic no-slip, adiabatic free-slip, and isothermal. The calculations show that the wall boundary condition has a significant effect on the generation and amplification of pressure waves and consequently on the flame dynamics. In the early stages of flame propagation, the flame behaves in a similar manner for different boundary conditions, that is, the flame develops a tulip shape that further evolves into a distorted tulip flame (DTF) through Rayleigh-Taylor instability arising from acoustic-flame interaction. Significant differences, however, arise after DTF formation in the late stages, especially when the primary acoustic wave is amplified to form a shock wave in the adiabatic free-slip and isothermal cases. The shock-flame interactions facilitate the formation of a series of increasingly corrugated flames by triggering the Richtmyer–Meshkov instabilities. The way how the lateral flame fronts touch the tube sidewalls to generate the primary acoustics and the heat conduction through the tube sidewalls play an important role in the generation and amplification of the pressure waves. [ABSTRACT FROM AUTHOR]

• The influence of a sho (ϸ)-shaped tube on the spontaneous ignition is investigated. • There are complex shock wave interactions in the bend section. • Spontaneous ignition is more prone to occur in the bend section. • The flame in the bend section cannot spread to the straight section. • There are two jet fires with a long-time interval outside the sho-shaped tube. The geometry of the extension tube has a great influence on the shock wave propagation and spontaneous ignition of high-pressure hydrogen release in this paper, piezoelectric pressure transducers, photodiodes and a high-speed camera are used to study the shock wave propagation and spontaneous ignition of high-pressure hydrogen released to the downstream sho (ϸ)-shaped extension tube. Experimental results show that the intensity of the leading shock wave is weakened due to the presence of branches when it propagates in the straight section of the sho-shaped tube, and a strong reflected shock wave is generated in the bend section. Spontaneous ignition is more prone to occur in the bend section than in the straight section, with a large optical signal value and long flame duration. However, due to the complex structure of the extension tube, there are still cases of the hydrogen flame extinguishing inside the tube even under high burst pressure. The flame detection time after the leading shock wave at the measured positions decreases with increasing burst pressure, and the time in the bend section is greater than that of the straight section. Radial flame expansion, flame separation, downstream flame extinction and upstream flame development, primary jet fire and secondary jet fire are successively observed outside the tube. [ABSTRACT FROM AUTHOR]

The residual electricity contained in spent lithium-ion batteries probably triggers the thermal runaway and results in irreparable disaster during recycling. Chemical discharge is a common method to eliminate hazards by immersing batteries in an aqueous solution to release the remnant energy. However, a high-efficiency discharge solution usually causes severe corrosion of the battery shell, inducing safety accidents. In this work, theoretical and experimental studies are carried out in various solutions to investigate the efficiency and corrosion of chemical discharge strategy. The results suggest that zinc acetate solution is a potential discharge medium with excellent comprehensive properties compared with NaCl, MnSO 4 , FeSO 4 , and KAc solutions. Electrolytic reactions and external short circuit have been proved to be the essential causes of high discharge efficiency. Adsorption theory and Kolbe reaction are used to explain the low corrosion of battery shells in acetate solutions. Besides, the thermal stability of treated spent batteries also validates our discharge strategy's feasibility and ensures safety during transportation, storage, and recycling. The high-efficiency discharge mechanism and excellent corrosion inhibition of spent lithium-ion battery immersing in zinc acetate solution. [Display omitted] • Electrolysis and external short circuit ensure the high discharge efficiency. • Manganese sulfate cannot effectively discharge spent batteries. • Zinc acetate solution is first proposed as a potential discharge medium. • Adsorption theory and Kolbe reaction explain the low corrosion in acetate solution. [ABSTRACT FROM AUTHOR]

Nowadays, an effective and clean extinguishing agent or technology is highly desirable for lithium-ion battery (LIB) fires. Herein, the physicochemical properties and extinguishing effects of various extinguishing agents on 243 Ah lithium iron phosphate (LFP) battery fires are investigated systematically. The extinguishing mechanisms are deeply analyzed and the performance is comprehensively evaluated from the aspects of thermal runaway (TR) and toxicity suppression, cooling and extinguishing efficiency. Compared with HFC-227ea, C 6 F 12 O can absorb more heat through vaporization, thereby improving extinguishing and cooling efficiency. The lack of chemical inhibition effect and the tiny droplet size make water mist unable to suppress the high-temperature jet fire, but it has the lowest toxicity and highest cooling efficiency of 54.6%. F-500 and FireIce can improve the extinguishing performance of the water mist by encapsulating and taking hydrocarbon fuel away from the fire zone and inhibiting free radicals in the flame, respectively. 3% F-500 has the extinguishing efficiency of 78.4% and TR efficiency of 64.1%, while maintaining the cooling performance well. In the future, a novel type of fire-extinguishing agent with high heat capacity and latent heat, excellent extinguishing performance, high wettability, low toxicity and insulating properties is expected to be developed for LIB fires. [Display omitted] [ABSTRACT FROM AUTHOR]

Spontaneous ignition induced by high-pressure hydrogen leakage has primarily been discussed qualitatively, focusing on factors such as release pressure, downstream tube size, and the rupture of the burst disk. However, quantitative investigations and prediction models remain limited and unclear. In this paper, we introduce the relative molecular mass M and delve into its influence on the critical pressure threshold for spontaneous ignition of high-pressure hydrogen leaks. Additionally, we introduce the mass flow rate Q , as a metric to quantify the impact of opening area and shape on the ignition process. By integrating six key factors, including tube diameter D , tube length L , atmospheric pressure P a , burst disk opening time t , gas mass flow rate Q , and gas relative molecular mass M , four dimensionless factors affecting the critical leakage pressure were determined by using similarity analysis. The correlation between the dimensionless numbers was verified by correlation analysis and calibrated to the experiments of this paper and other authors. Finally, a critical criterion for spontaneous ignition from leakage in high-pressure hydrogen tubes was established to provide a basis for safety evaluation and prevention techniques for high-pressure hydrogen. [Display omitted] • The effect of the relative molecular mass of gases in the high-pressure region on the spontaneous ignition of high-pressure hydrogen leakage is discussed. • The dimensionless parameter affecting the critical pressure for spontaneous ignition of high-pressure hydrogen leakage is investigated. • The critical pressure criterion for the spontaneous ignition of high-pressure hydrogen leakage is established. [ABSTRACT FROM AUTHOR]

Thermal runaway initiated in an individual cell may transfer heat to adjacent cells, and cause thermal runaway propagation. Thus, mitigation and prevention of thermal runaway propagation using extinguishing agents are significant. In this work, fire and extinguishing tests on 117 Ah LIBs with Li(Ni 0.8 Co 0.1 Mn 0.1)O 2 (NCM)/graphite electrodes are investigated. The suppression effects of different extinguishing agents including HFC-227ea, C 6 F 12 O and water spray on thermal runaway propagation in confined space were compared. Results show that thermal runaway propagation can occur in LIBs module even with thermal management measures. When activated immediately after the thermal runaway of the first cell, each agent can extinguish the LIBs module fire. However, the cooling capacity of extinguishing agent is the key factor to suppress thermal runaway propagation. The heat dissipation of HFC-227ea, C 6 F 12 O and water spray in fire extinguishing test is 24.8 kJ, 111 kJ and 459.8 kJ, respectively. Thus, HFC-227ea can hardly suppress the thermal runaway propagation. Although C 6 F 12 O can not prevent thermal runaway propagation, it can decrease the battery temperature, slow down the heat transfer rate and prolong the propagation time. While water spray has the best cooling effect, which can prevent thermal runaway propagation. [ABSTRACT FROM AUTHOR]