Battery Swelling Reason Analysis
Description
Battery swelling is a common and serious issue that may pose safety risks in severe cases,it is usually caused by multiple factors,the following is a detailed analysis of the causes of battery swelling:
1.Overcharging causes battery swelling
When a battery is overcharged, the chemical reactions inside it will lose balance,take lithium-ion batteries as an example,during the normal charging process, lithium ions are released from the positive electrode and intercalated into the negative electrode through the electrolyte,when overcharging occurs, the intercalation of lithium ions in the negative electrode exceeds its normal holding capacity,
And lithium metal dendrites will form on the surface of the negative electrode,these dendrites keep growing, which not only punctures the separator of the battery, causing a short circuit between the positive and negative electrodes, but also generates a large amount of heat and gas (such as carbon dioxide produced by the decomposition of carbonate solvents) inside the battery, thereby increasing the internal pressure of the battery and eventually leading to battery bulging,in addition, overcharging will accelerate the aging and decomposition of the internal materials of the battery, further damaging the structure and performance of the battery.
2.Over-discharge causes battery swelling
Excessive discharge of the battery can also cause damage to the battery and may lead to bulging,when the battery discharges below its designed minimum voltage, the electrode materials inside the battery will undergo irreversible changes.
For instance, the negative electrode material may undergo side reactions with the electrolyte, generating gas,at the same time, over-discharging may also disrupt the chemical equilibrium inside the battery, increasing its internal impedance,during the subsequent charging process, the battery’s heat generation intensifies, and the amount of gas produced increases, eventually leading to battery swelling.
3.The influence of temperature factors
The operating temperature of a battery has a significant impact on its performance and safety,if a battery is used or charged for a long time in a high-temperature environment, the chemical reaction rate inside the battery will increase, resulting in an increase in the gas production rate inside the battery,for instance, at high temperatures, the stability of electrolytes will decrease and they are prone to decomposition reactions that produce gases,in addition, high temperatures will accelerate the aging of electrode materials and the decomposition of active substances, further affecting the performance and safety of the battery,on the contrary, in a low-temperature environment, the charging and discharging performance of the battery will decline, and the internal resistance of the battery will increase,this may cause local overheating of the battery during the charging process, thereby triggering bulging problems.
4.Battery quality problem causes battery swelling
The quality defect of the battery itself is also an important cause of bulging,some inferior batteries may have problems such as non-standard processes and substandard material quality during the production process. For instance, if the thickness of the separator inside the battery is uneven, and there are holes or cracks, it will lead to insufficient isolation between the positive and negative electrodes, which is prone to short circuits and subsequently cause swelling.
In addition, issues such as low purity of electrode materials and unreasonable proportioning of active substances can also affect the performance and stability of the battery, increasing the risk of swelling.
5.Usage environment and improper operation
In addition to the above factors, the usage environment and operation mode of the battery will also have an impact on it,for instance, when a battery is subjected to physical damage such as squeezing, collision or puncture, the internal structure of the battery may be damaged, causing a short circuit between the positive and negative electrodes and thus leading to swelling.
In addition, when using batteries in a humid environment, moisture may enter the battery interior, react with the electrolyte, produce gas, and cause the battery to bulge. At the same time, frequent deep charging and discharging, using mismatched chargers and other improper operations will also accelerate the aging and damage of the battery, increasing the possibility of swelling.
6.Conclusion
Battery swelling is the result of the combined effect of multiple factors, mainly including overcharging, overdischarging, abnormal temperature, battery quality issues, as well as improper usage environment and operation.
To prevent battery swelling, we should choose reliable battery products, use appropriate chargers, and follow the correct charging and usage methods,we should avoid operating the battery in extreme temperature environments and also pay attention to protecting the battery to prevent physical damage,once the battery is found to be bulging, its use should be stopped immediately to ensure safety.