With the rapid development of science and technology, the use range and role of lithium batteries have long been self-evident, but lithium battery accidents are constantly emerging in our daily lives, which constantly plagues us. In view of this, the 18650 Battery Factory has specially organized Lithium ion common problems cause analysis and solutions, I hope to provide convenience for everyone.
18650 Battery 3.7 V 2500mah
First, the voltage is inconsistent, and individual is too low
1. Large self-discharge causes low voltage
The self-discharge of the battery cell is large, which makes its voltage drop faster than others. The low voltage can be eliminated by checking the voltage after storage.
2. Low voltage due to uneven charging
When the battery is charged after the test, the charging of the battery cells is uneven due to the contact resistance or the charging current of the detection cabinet is inconsistent. The difference in voltage measured during short-term storage (12 hours) is small, but the voltage difference is large during long-term storage. This low voltage has no quality problem and can be solved by charging. Store the voltage for more than 24 hours after charging in production.
Second, the internal resistance is too large
1. Caused by differences in detection equipment
If the detection accuracy is not enough or the contact with the electrical group cannot be eliminated, the internal resistance of the display will be too large. The internal resistance instrument should be tested by the principle of AC bridge method.
2. Storage time is too long
Lithium batteries are stored for too long, causing excessive capacity loss, internal passivation, and internal resistance becoming large, which can be solved by charging and discharging activation.
3. Large internal resistance caused by abnormal heating
During the processing of batteries (spot welding, ultrasonic, etc.), the battery is abnormally heated, which causes the diaphragm to thermally close, and the internal resistance is seriously increased.
Third, 50ah Lithium Battery expansion
1. Lithium battery swells while charging
When a lithium battery is being charged, the lithium battery will naturally swell, but generally it does not exceed 0.1mm, but overcharging will cause the electrolyte to decompose, the internal pressure will increase, and the lithium battery will swell.
2. Swelling during processing
Generally, abnormal processing (such as short circuit, overheating, etc.) causes the internal electrolyte to be overheated to decompose, and the lithium battery expands.
3. Swelling during cycling
When the battery is cycling, the thickness will increase with the number of cycles, but it will not increase after more than 50 weeks. Generally, the normal increase is 0.3 ~ 0.6 mm, and the aluminum case is more serious. This phenomenon is caused by normal battery reaction. However, if the shell thickness is increased or the internal materials are reduced, the swelling phenomenon can be appropriately reduced.
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