The bulging of lithium batteries may be caused by the following reasons:
1. Lithium battery bulge caused by overcharging
Overcharging will cause all the lithium ions in the positive electrode material to run into the negative electrode material, causing the original full grid of the positive electrode to deform and collapse. In this process, the lithium ions in the negative electrode will become more and more, and the excessive accumulation will make the lithium atoms grow stumps. Crystallization, causing the battery to bulge. This is also a major reason for the decline in the power of lithium battery packs.
2. Bumps caused by over-discharge
The SEI film will have a protective effect on the negative electrode material, making the material structure not easy to collapse, and can increase the cycle life of the electrode material. There will be a little change in the SEI film during the charge and discharge process, mainly because some organic substances will undergo reversible changes. After the battery is over-discharged, the SEI film is reversibly damaged, and the SEI protecting the negative electrode material is destroyed, causing the negative electrode material to collapse, thereby forming a lithium battery bulging phenomenon. If the charger used does not meet the requirements, it may cause the battery to bulge, or cause a safety accident or even explode.
3. Manufacturing process problems
In the manufacture of lithium battery packs, the electrode coating is uneven and the production process is relatively rough, which may also cause lithium battery bulging.
Therefore, mobile phone lithium batteries must be tested after they are manufactured, including appearance testing, safety testing, reliability testing, and electrochemical testing. In order to improve the test efficiency of lithium batteries and ensure the stability of the test, the battery test module—shrapnel microneedle module can be used as the connection medium for mobile phone lithium battery tests. It mainly provides high-current transmission and signal connection. Maintain stable overcurrent capability within the range of -50A, reliable connection and stable performance.
