If the voltage is below 2V, the internal structure of lithium battery will be damaged, and the battery life will be affected. Root cause 1: High self-discharge, which causes low voltage. Solution: Charge the bare lithium battery directly using the charger with over-voltage protection, but do not use universal charge. It could be quite dangerous. Ro. Root cause 1: Detecting equipment differences. If the detection accuracy is not enough or the contact resistance cannot be eliminated, it will show that the internal resistance is too large. Solution: The internal resistance should be tested by the principle of AC (Alternating Current) bridge method. Root cause 2: Too long storage time. Lithium bat. Case 1: Lithium battery expands when charging. When charging lithium battery, it will naturally expand, but generally not more than 0.1 mm. However, overcharging will cause electrolyte decomposition, increase internal pressure, and finally lithium batteries expansion. Solution: Don't overcharge, especially don't charge for more than 12 hours at a t. Root cause 1: Incorrect spot welding location. Solution: The correct spot welding position should be at the bottom or marked “A” or “-” side. Unmarked sides and large surface can't be spot welded. Root cause 2: Too large spot welding current. Some spot-welded nickel strips are poorly made, so it requires a large current to spot weld, which comes wi. Root cause 1: Overcharge If the protection circuit or the detection cabinet is out of control, the charging voltage will be greater than 5V, causing the electrolyte decomposition, violent reaction inside the battery, rapid rise of internal pressure of the battery. Eventually the battery explodes. Root cause 2: Large ultrasonic energy When welding t.