Analysis and solutions of common problems of lithium ion batteries
With the rapid development of science and technology, the scope and function of lithium batteries have long been self-evident, but in our daily life, lithium battery accidents have occurred from time to time and have been bothering us. In view of this, the lithium battery customization manufacturer guanlida battery has specially arranged the cause analysis and solutions of common problems of lithium ion, hoping to provide convenience for everyone. One. The voltage is inconsistent, and the individual voltage is low by 1.
The low voltage Core self-discharge caused by high self-discharge is large, which makes the voltage drop faster than others. The voltage drop can be eliminated by checking the voltage after storage. 2.
Low voltage caused by uneven charging when the battery is charged after the test, the charge of the core is uneven due to the inconsistency of the contact resistance or charging current of the detection cabinet. In short-term storage (12 hours)
There is a small difference in the measured voltage, but there is a big difference in the voltage during long-term storage.
The low voltage has no quality problem and can be solved by charging.
After charging in production, store for more than 24 hours to measure the voltage.
Second, lithium battery expansion 1.
When charging, the lithium battery will expand. When the lithium battery is charged, the lithium battery will naturally expand, but generally not more than 0.
1mm, but overcharging will lead to electrolyte decomposition, internal pressure increase and lithium battery expansion.
2. Expansion during processing, generally speaking, abnormal processing (Such as short circuit, overheating, etc)
It will cause the internal heated electrolyte to decompose and the lithium battery to expand.
3. Expansion during cycle, battery thickness increases with the increase of cycle times, but does not increase after more than 50 weeks. At 0. 3 ≤ 0.
At 6mm, the normal growth of aluminum shell is more serious, which is caused by normal battery reaction.
However, if the thickness of the shell is increased or the internal material is reduced, the expansion phenomenon can be appropriately reduced.
Third, the internal resistance is too large.
The difference of test equipment, if the detection accuracy is not enough or the contact power group cannot be eliminated, the internal resistance of the display is too large.
The internal resistance meter test shall be based on the principle of AC bridge method.
Too long storage time, excessive storage of lithium batteries will lead to excessive capacity loss, internal passivation and internal resistance changes, which can be solved by charging and discharging activation. 2.
Abnormal heating of internal resistance battery caused by abnormal heat is caused by processing of iron core (Spot welding, ultrasonic, etc)
Caused, the diaphragm to produce thermal closure phenomenon, internal resistance increases.
Fourth, the battery explosion, usually the battery explosion is as follows: 1. overcharge explosion, if the protection circuit is out of control or the detection cabinet is out of control, the charging voltage is greater than 5 V, resulting in electrolyte decomposition, severe internal reaction of the battery, rapid rise of the internal pressure of the battery, and battery explosion.
2. Over-current Explosion, protection circuit or detection cabinet out of control, charging current is too large, resulting in lithium ion embedding, while metal lithium is formed on the electrode surface, penetrating the diaphragm, direct short circuit of positive and negative poles causes explosion (Rarely occurs). 3.
Explosion in the process of ultrasonic welding of plastic shell. When the plastic shell is welded by ultrasonic wave, ultrasonic energy is transferred to the battery core due to equipment reasons.
Ultrasonic energy melts the diaphragm inside the battery, and the positive and negative electrodes are directly short-circuited, resulting in an explosion.
4. Explosion during spot welding. During spot welding, excessive current will cause explosion of internal short circuit.
In addition, in the spot welding process, the positive connecting plate is directly connected with the negative electrode, resulting in the explosion of the positive and negative electrodes after direct short circuit.
5. Over-discharge explosion, battery over-discharge or over-current discharge (3C or above)
It often causes the negative copper foil to dissolve and deposit on the partition plate, causing direct short circuit between the positive and negative electrodes to cause explosion (Rarely occurs).
Five, improper processing, the main research results are as follows :(1)
Due to the forced movement of the spot welding positive connector, the positive contact of the iron core is poor, and the internal resistance of the iron core is increased. (2)
The spot welding joint is not firm and the contact resistance is large, which increases the internal resistance of the battery.
In short, the choice of lithium battery products should choose professional lithium battery manufacturers to produce high quality, high quality lithium battery products, in order to effectively avoid problems.