Things to pay attention to when the battery pack is sorted by the lithium battery pack factory

Battery packs are widely used. All batteries including lithium batteries can use battery PACK technology. The threshold of battery PACK is low and it can be operated with a certain amount of battery knowledge. However, in actual operation, you may encounter many unknowns. The problem cannot be solved. Now the lithium battery PACK factory sorts out the reasons and solutions, and gives you some reference. 1. Cell inspection 1) The voltage consistency is poor, and the cell has a certain voltage difference. ① The self-discharge of the battery cell will cause a large change in its voltage. This is more obvious in nickel batteries that have been placed for a long time, and there are fewer lithium batteries. When it is found that there is a voltage difference between the batteries, if the batch of batteries is replaced unconditionally, then the batteries need to be re-capacity screening. ②When charging, the battery cells are not evenly charged due to the inconsistent contact resistance or the inconsistent charging current of the detection cabinet. Short-term storage (within 12 hours), the measured voltage difference is small, but the long-term storage voltage difference is large, this is solved by charging, and there is no quality problem. During production, it can be in the charged state for more than 24 hours (standstill). Measurement. 2) The internal resistance is too large. ①The reason for the equipment needs to be checked at the first time whether it is caused by the equipment. Check the value several times. If there is a large deviation, check the equipment. Long storage time. Long storage time of the battery will cause internal passivation, which can be resolved by re-differentiating. Abnormal heating causes a large internal resistance. The internal resistance increases due to the heating of the battery cell during welding. 2. Lithium battery pack process issues and precautions 1) Lithium battery expansion ① Expansion during charging When charging, the lithium battery will naturally expand, but generally does not exceed 0.1mm. But if overcharged, this phenomenon will be exacerbated. ②Expanded lithium battery will expand during the first 50 charging cycles when it is cycled, and it will generally increase by 0.3-0.5mm. This is a normal battery reaction. 2) The battery loses power after spot welding. ① If the voltage after spot welding is lower than 3.7V, it may be due to the excessive spot welding current that causes the internal diaphragm of the battery cell to break down and short circuit, causing the voltage to drop too fast. Generally, it is caused by the incorrect spot welding position. The correct spot welding position should be spot welding on the bottom or side with the mark 'A' or''. Spot welding is not allowed on the side and large side without marking. The battery power loss after spot welding may also be caused by the self-consumption of the battery cell itself. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Lithium battery pack manufacturers analyze the thermal shaping process of soft pack lithium-ion batteries