The causes of safety hazards in lithium batteries

Internal factors

Thermal stability issue: Lithium batteries generate heat during the charging and discharging process, and when the internal temperature of the battery is too high, it may cause thermal runaway. For example, positive electrode materials may decompose at high temperatures, releasing oxygen and reacting violently with electrolytes, leading to battery combustion or even explosion.

Impurities in battery materials: If the electrode materials, electrolyte, etc. inside the battery contain impurities, they may form micro short circuits inside the battery, causing safety issues. For example, metal impurities in electrode materials may puncture the membrane, causing direct contact between the positive and negative electrodes.

Design flaw: The structural design of the battery is unreasonable, such as too small electrode spacing, uneven diaphragm thickness, etc., which may lead to internal short circuits and other problems during the use of the battery.

External factors

Overcharging and over discharging: When a lithium battery is overcharged or over discharged, it can disrupt the chemical balance inside the battery. Overcharging may cause lithium deposition on the positive electrode of the battery, and the growth of lithium dendrites may puncture the separator, leading to a short circuit; Overdischarge may damage the electrode material structure inside the battery, reduce battery performance, and even cause safety accidents.

High temperature and low temperature environment: In high temperature environments, the chemical reaction rate inside lithium batteries accelerates, making it easy to accumulate heat and increasing the risk of thermal runaway. In low-temperature environments, the electrolyte of the battery may freeze, leading to an increase in internal resistance, a decrease in charging and discharging efficiency, and possibly causing a decline in battery performance or even safety issues.

Squeezing puncture: When the battery is subjected to external force squeezing or puncturing, the internal electrodes and separators may be damaged, causing a short circuit between the positive and negative electrodes, instantly releasing a large amount of energy, and triggering combustion or explosion.