The common faults and causes of lithium batteries are as follows:
1. Low battery capacity
Causes: a. The amount of attached material is too small; b. The amount of attached material on both sides of the pole piece is quite different; c. The pole piece is broken; d. The electrolyte is less; e. The conductivity of the electrolyte is low; f. Not well prepared; g. The porosity of the diaphragm is small; h. The adhesive is aging → the attachment material falls off; i. The winding core is too thick (not dried or the electrolyte is not penetrated) j. The material has a small specific capacity.
2. High internal resistance of battery
Causes: a. Welding of negative electrode and tab; b. Welding of positive electrode and tab; c. Welding of positive electrode and cap; d. Welding of negative electrode and shell; e. Large contact resistance between rivet and platen ; f. The positive electrode has no conductive agent; g. The electrolyte has no lithium salt; h. The battery has been short-circuited; i. The porosity of the separator paper is small.
3. Low battery voltage
Causes: a. Side reactions (decomposition of electrolyte; impurities in the positive electrode; water); b. Not well formed (SEI film is not formed safely); c. Customer's circuit board leakage (referring to the batteries returned by the customer after processing ); d. The customer did not spot welding as required (cells processed by the customer); e. burrs; f. micro-short circuit; g.
4. The reasons for over-thickness are as follows:
a. Weld leakage; b. Electrolyte decomposition; c. Undrying moisture; d. Poor sealing performance of cap; e. Shell wall too thick; f. Shell too thick; g. ; pole pieces not compacted; diaphragm too thick).
5. Abnormal battery formation
a. Not well formed (SEI film is incomplete and dense); b. Baking temperature is too high → binder aging → stripping; c. The specific capacity of the negative electrode is low; d. . The cap leaks and the weld leaks; f. The electrolyte is decomposed and the conductivity is reduced.
6. Battery explosion
a. The sub-container is faulty (causing overcharge); b. The diaphragm closure effect is poor; c. Internal short circuit.
7. Battery short circuit
a. Material dust; b. Broken when the shell is installed; c. Scraper (diaphragm paper is too small or not properly padded); d. Uneven winding; e. Not wrapped properly; f. There is a hole in the diaphragm; g.
8. The battery is disconnected.
a) The tabs and rivets are not welded properly, or the effective welding spot area is small;
b) The connecting piece is broken (the connecting piece is too short or it is too low when spot welding with the pole piece).