Li-ion Battery Protection ICIntroduction to Common FAQs and Repair Methods:
The 12V lithium-ion battery is obtained by connecting multiple 3.7V lithium-ion batteries in series, reaching a voltage close to 12V. When串联 lithium-ion batteries are used, a 12V lithium-ion battery protection board is necessary to safeguard the battery pack. It ensures equal charging for each individual battery cell when the battery is fully charged, effectively addressing flaws in the series circuit. What should be done when the 12V lithium-ion battery pack protection board exhibits malfunctions? Below, we analyze and provide solutions for common issues with the protection board.
I. No voltage or abnormal voltage
In the absence of voltage or abnormal voltage conditions, set the multimeter to the DC 20V range, then use the red test lead to contact the positive terminal of the lithium-ion battery cell, and the black test lead to the negative terminal. If the multimeter shows no voltage or very low voltage, it indicates that the cell is damaged. Pay attention to check if the protection board's positive and negative terminals are reversed; if they are, charging the lithium-ion battery pack with the charger would be equivalent to forcing over-discharge.
No overcurrent protection.
Firstly, check if there are any issues with the circuit of the overcurrent detection foot; if so, replace the protection IC.
III. No resistance or excessive resistance
To find the cause in identifying circuits from resistance welding pads, inspect whether there is any soldering failure, if any resistors are misaligned, and if there are any short circuits or open circuits.
Unable to charge
Select the 20V range on the multimeter using the switch, then touch the red probe to the positive terminal of the battery cell or the protection board. If the multimeter displays voltage, we must stop the analysis based on the following conditions: whether there is an output voltage and whether the battery cell voltage is normal. If all these voltages are abnormal, we can fundamentally determine that the protection IC or MOSFET has been damaged, and at this point, we can proceed with the replacement of these two components.
V. No internal resistance or excessive internal resistance
If there is no internal resistance, check if the MOSFET pins are damaged; if so, simply replace the MOSFET.
2. If the internal resistance is too high, use a probe to contact the lithium-ion battery protection board of the electric fish, to check for poor contact or excessive oxidation. Additionally, inspect if there are too many nickel plates on the battery cell, as an excessive number of nickel plates on the cell can also cause a high internal resistance.
The lithium-ion battery protection board repair methods employed here are fundamentally comparative, visual, voltage measurement, and conductive/insulative switch testing. By mastering these techniques, one can confidently perform skilled repairs on lithium-ion battery protection boards.
