Lithium ion problem causes’ analysis and solution (1)
With the rapid development of science and technology, the scope and role of lithium batteries have long been self-evident, but in our daily life, lithium battery accidents are always emerging, always plagued us, in view of this, Xiaobian special finishing lithium The reasons for common ion problems are analyzed and solutions are provided to provide convenience for everyone.
The voltage is inconsistent, individual low
1. Low self-discharge voltage
The self-discharge of the battery core makes its voltage decrease faster than others, and the voltage can be eliminated by storing the post-check voltage.
2. Uneven charging causes low voltage
After the battery is detected, when the battery is charged, the battery is not uniformly charged due to the inconsistent contact resistance or the detection cabinet charging current. In the short-term storage (12 hours) the voltage difference is very small, but the long-term storage voltage difference is large, this low voltage and no quality problems can be solved by charging. After storage in the production of stored voltage over 24 hours.
The internal resistance is too large
1. Detecting device differences
If the detection accuracy is not enough or the contact group cannot be eliminated, the internal resistance of the display will be too large. Therefore, the principle of AC bridge method should be used to test the internal resistance instrument.
2. Store too long
Lithium batteries are stored for too long, resulting in excessive capacity loss, internal passivation, and increased internal resistance, which can be solved by charging and discharging.
3. Abnormal heat caused by large internal resistance
In the processing (spot welding, ultrasonic, etc.) of the battery cell, the battery is abnormally heated, so that the diaphragm generates a thermal closing phenomenon, and the internal resistance is greatly increased.
Lithium battery expansion
1. Lithium battery expands when charging
When the lithium battery is being charged, the lithium battery will naturally expand, but generally it does not exceed 0.1 mm, but the overcharge will cause the electrolyte to decompose, the internal pressure increases, and the lithium battery expands.
2. Expansion during processing
In general, abnormal processing (such as short-circuit, overheating, etc.) occurs, and internal electrolyte is too hot to decompose and the lithium battery expands.
3. Expansion during cycling
When the battery is in circulation, the thickness will increase with the number of cycles, but it will not increase after more than 50 weeks. Generally, the normal increase will be 0.3~0.6 mm. The aluminum shell is more serious. This phenomenon is caused by the normal battery reaction. However, if you increase the thickness of the shell or reduce the internal material, you can properly reduce the expansion phenomenon.