The thermal safety of lithium-ion traction batteries is a highly concerning issue in the field of electric transportation. The large amount of gas emissions during the thermal runaway process of batteries has high safety hazards, such as fire and explosion. The quantitative analysis of emissions is one of the important challenges in testing and evaluating battery safety. Focusing on quantifying gas emissions using large-scale thermal propagation in battery modules and packs, based on the idea of cell result multiplication, this article conducts a thermal runaway emission analysis of a single cell and a module and compares the behavior of thermal runaway and gas emissions of the cell and module from the perspectives of temperature, pressure, gas composition, and battery morphology. The feasibility of the cell result multiplication method is verified from the perspective of experimental data.

Thermal safety of lithium-ion traction batteries is a highly concerned issue in the field of electric transportation. The large amount of gas emission during the thermal runaway process of batteries has highly safety hazards such as fire and explosion. Quantitative analysis of emission is one of the important challenges for testing and evaluating battery safety. Focus on quantifying the gas emission through large-scale thermal propagation in battery modules and packs, based on the idea of cell result multiplication, this article conducts thermal runaway emission analysis on single cell and modules, and compares the behavior of thermal runaway and gas emission of the cell and module from the aspects of temperature, pressure, gas composition and battery morphology. The feasibility of the cell result multiplication method was verified from the perspective of experimental data.

As a key energy storage component, the rapid detection of battery status and safety and reliability evaluation of the lithium battery have attracted more attention. Among them, the expansion behavior evaluation technology of the lithium battery, as a non-destructive rapid detection method, is an effective means to evaluate the health status of the battery and realize early safety warning. This paper reviews the causes of the current expansion phenomenon of lithium battery, the development status of expansion evaluation technology and the evaluation method of expansion test results. The existing expansion behavior evaluation technology under constant pressure and constant displacement conditions are classified and discussed. By accurately obtaining changes in the internal state of the battery, it can accurately predict and evaluate performance, life and safety. By obtaining the critical conditions of battery expansion, the design and optimization of the module structure are guided. On this basis, the limitations of lithium battery expansion test under different boundary conditions are further discussed. The future development of battery expansion test methods and battery expansion control and solutions are proposed. This paper aims to optimize the evaluation technology of lithium battery expansion behavior and improve the safety and reliability of the battery.

The new energy vehicle (NEV) industry is expanding globally, yet safety accidents induced by collisions have become a major challenge to its high-quality development. In addition, the risks associated with battery state variations from fast-charging cycling cannot be ignored. To investigate the coupled effects of electrochemical degradation and mechanical loading on battery safety, a series of cross-factor-controlled mechanical experiments has been proposed based on 12 prismatic lithium-ion batteries across three aging states and two loading directions. The results indicate that the difference in loading orientation affects the mechanical safety responses. Under horizontal loading, interlayer slip dissipates the impact energy, and damage is concentrated in a localized area. In contrast, vertical loading is prone to inducing penetration-type damage to the structure, characterized by large-scale interlayer slip and multi-point separator damage. Moreover, once thermal runaway is triggered under vertical loading, the peak surface temperature is significantly higher. Loading orientation exerts an influence on the load-bearing capacity under mechanical damage, while electrochemical aging further reduces the safety margin of the batteries. The coupling effect of these two factors exacerbates the risk of impact failure. Consequently, if testing is based solely on fresh batteries, it tends to overestimate the safety boundary of in-service batteries. These results provide theoretical and data support for optimizing the structural design of battery systems, which is of great significance for the high-quality advancement of the NEV industry.