Common fault problems and causes of lithium batteries

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.

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;

e. 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.

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).