Effect of aging temperature on thermal stability of lithium-ion batteries: Part A-High-temperature aging

Aging and thermal runaway are two significant reasons why lithium-ion batteries are struggling to become more widely available. Aging at different temperatures causes differences in the aging mechanism and thermal runaway behaviour of lithium-ion batteries. In this paper, four sets of commercial lithium-ion batteries are aged at 25 degrees C, 40 degrees C, 60 degrees C and 80 degrees C respectively for 100 cycles. Then the morphology and composition of the electrodes and separators are analysed in order to reveal the mechanism of changes in electrical performance and thermal stability due to aging at different temperatures. The differences in the decomposition products of the solid electrolyte intermediate (SEI) layer are an important factor in inducing changes in thermal runaway behaviour. At 60 degrees C, the accumulation of SEI decomposition products results in thicker SEI layers and shorter thermal runaway times. At 80 degrees C, the SEI decomposition products are heavily transformed into particles with a loose structure, generating a large amount of gas in the process, which further leads to the rupture of the aluminium-plastic film and the evaporation of the electrolyte, with a longer duration of thermal runaway and a lower maximum temperature.

Automated summary

Aging and thermal runaway are major challenges for widespread adoption of lithium-ion batteries. Aging at different temperatures leads to differences in aging mechanisms and thermal runaway behavior of the batteries. This study investigates the changes in electrical performance and thermal stability of commercial lithium-ion batteries aged at temperatures of 25°C, 40°C, 60°C, and 80°C for 100 cycles, analyzing the morphology and composition of the electrodes and separators. The decomposition products of the solid electrolyte intermediate layer are found to play a crucial role in inducing changes in thermal runaway behavior.