Summary of abnormal factors of lithium battery cells

A summary of the causes of abnormal lithium batteries, including lithium battery capacity, lithium battery internal resistance, lithium battery voltage, ultra-thick size, open circuit, etc. The battery capital has briefly summarized and shared with everyone. 1. Reasons for low battery capacity: 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 electrolyte conductivity is low; f. The positive and negative electrodes are not matched; g. The diaphragm porosity is small; h. The adhesive is aging → the attached material falls off; i. The core is too thick (not dried or the electrolyte is not penetrated) j. The volume is not fully charged when the volume is divided; k. The specific capacity of the positive and negative materials is small. 2. Reasons for the high internal resistance of the battery: a. Welding of the negative electrode and the tab; b. Welding of the positive electrode and the tab; c. Welding of the positive electrode and the cap; d. Welding the negative electrode and the shell; e. Rivet The internal resistance is large in contact with the pressure plate; f. No conductive agent is added to the positive electrode; g. There is no lithium salt in the electrolyte; h. The battery has been short-circuited; i. The porosity of the diaphragm paper is small. 3. Reasons for low battery voltage: a. Side reactions (decomposition of electrolyte; impurities in the positive electrode; water); b. Incomplete formation (SEI film is not formed to be safe); c. Leakage of the customer's circuit board (refers to the customer after processing The batteries sent back); d. The customer did not spot welding as required (the batteries processed by the customer); e. Burrs; f. Micro short circuits; g. Dendrites in the negative electrode. 4. Super thick a. Welding seam leakage; b. Electrolyte decomposition; c. Undried moisture; d. Cap sealing is poor; e. Shell wall is too thick; f. Shell is too thick; g. Roll core is too thick ( Too much attached material; the pole piece is not compacted; the diaphragm is too thick). 5. Abnormal battery formation a. Not formed well (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 positive electrode has too much material and the negative electrode Less attached materials; e. Cap leaks and welds leak; f. Electrolyte decomposes, and conductivity decreases. 6. The battery explodes 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. The casing is broken; c. The ruler is scraped (the diaphragm paper is too small or not well-padded); d. The winding is uneven; e. Not wrapped properly; f. There is a hole in the diaphragm; g. Burr 8. Battery disconnection a) The lugs and rivets are not welded well, or the effective solder joint area is small; b) The connecting piece is broken (the connecting piece is too short or the welding is too low when spot welding with the pole piece)