The main impact of temperature on the stability of lithium batteries is that high temperatures can cause the decomposition reaction of the battery internal materials. Spotnit and Dahn found that under the continuous high temperature environment, the SEI membrane in the lithium battery first decomposed, and then reacted between the negative electrode material and the electrolyte, causing the membrane to melt. Finally, positive electrode materials and electrolyte decomposition. The decomposition temperature range of the SEI membrane is usually between 80 and 120°C. These changes in the battery can cause the lithium -ion channel to block, leading to the short circuit between the direct contact and the positive electrode, thereby releasing a large amount of heat.
In addition, the decomposition process of these materials will also produce a large amount of gas and heat, and the internal pressure of the battery will increase rapidly, leading to heat out of control, such as battery expansion, rupture, pressure relief valve rupture and aluminum foil melting. Once the heat is out of control, the temperature difference in the battery can reach 520°C. Obviously, this will cause major damage to the safety of battery. In addition, when the battery is exposed to extremely low temperature conditions for a long time, it will cause lithium precipitation at the negative electrode of the battery and form lithium dendritic.
discharge rate of 1-50°C and discharge time of 900 s
In severe cases, the SEI film is pierced, causing the battery to fail. Considering the efficiency and safety of lithium batteries, the temperature range that the lithium battery can withstand is widely-40～60°C. Low temperature can cause electrolyte curing and increased resistance, while high temperature can significantly reduce the battery capacity, life and safety. The best temperature range is 10-35°C.
