Lithium battery science popularization, lithium battery pack bulge causes and treatment methods
The development of lithium batteries was earlier, but due to fierce competition, some manufacturers have some quality problems in the production process, so that the safety of the battery can not be fully guaranteed. If it is used improperly or the manufacturing level is limited, it is easy to have problems such as electrolyte decomposition, which causes the battery bulge phenomenon. So why do lithium batteries bulge?
First, the basic structure analysis of lithium battery pack
The main material composition of lithium battery pack: positive electrode material, negative electrode material, electrolyte, diaphragm (isolation material) composition.
Positive electrode materials occupy an important position in lithium batteries, usually accounting for 30% to 40% of the battery cost, and its performance directly affects the performance and energy density of the battery. The negative electrode material needs to have a high specific capacity and good reversibility of charge and discharge to ensure the cycle performance and stability of the battery. The electrolyte transfers ions between the positive and negative electrodes, and its ionic conductivity directly affects the energy density and cycle life of the battery. The separator plays an important role in separating the positive and negative electrodes and ensuring the smooth ion channel in the battery. Its mechanical properties and chemical stability are crucial to the safety and performance of the battery.
Second, why does the lithium battery pack bulge?
There are three main reasons for lithium battery bulges:
1) Manufacturer production process problems: some manufacturers in order to save costs, the use of poor production environment or equipment to be eliminated, resulting in poor battery production quality, such as uneven coating, electrolyte mixed with dust.
2) The user's daily use habits: improper use such as: overcharge, over-discharge, use in high and low temperature harsh environments, etc., will also lead to battery bulges.
3) Long-term use and improper storage: the battery is not used for a long time and is not properly stored, which may lead to reduced battery performance, and even short circuit and bulging.
Among them, the reasons for the bulge caused by overcharge and overdischarge are as follows: Overcharge will cause the lithium ions of the positive electrode material to run into the negative electrode material, resulting in the deformation and collapse of the positive electrode, and the excessive accumulation of the lithium ions of the negative electrode to form a tree crystal, making the battery bulge. Excessive discharge will destroy the solid electrolyte interface film (SEI) of the negative electrode material, leading to the collapse of the negative electrode material, and also cause the battery bulge. Both of these conditions can lead to a violent reaction inside the battery, generating a lot of heat, leading to electrolyte gasification and causing the phenomenon of battery bulges.
Third, how to deal with lithium battery bulge safely?
1) Maintenance charge and discharge cycle: Avoid frequent complete charge and discharge, which can reduce the crystallization amount and delay the battery bulge phenomenon. It is generally recommended to supplement the battery after half of the power is used, and to fully charge the battery regularly (such as several months to half a year) to maintain the battery.
2) Dealing with bulged batteries: For the lithium battery that has been bulged, due to the power capacity has been seriously damaged, and there may be security risks, it can be directly discarded. The power of the bulge battery has been reduced after the short circuit, but there is still a certain danger.
3) Professional recycling: discarded lithium battery packs should be processed through professional recycling channels to avoid environmental pollution. If a suitable recycling channel cannot be found, the battery pack can be discarded to a garbage can dedicated to recycling lithium batteries for sorting and recycling.
Through the above methods, the occurrence of the bulge phenomenon of lithium battery packs can be delayed, and the waste lithium batteries can be properly disposed of to reduce the pollution to the environment.