Analysis of lithium battery explosion reasons

When the negative electrode capacity is insufficient, or there is no capacity, some or all of the lithium produced during the charging of lithium cannot be inserted between the anode graphite layer structure, and then it will analyze on the surface of the cathode. It will form "dendritic crystal". In the next time when charging, the protuberant part is easier to cause precipitation of lithium. After several dozens to hundreds of times of circulation charge and discharge, "dendritic crystal" grows up, and it will eventually pierce diaphragm paper, and make internal short circuit. Batteries discharge rapidly, produce a large amount of heat, burn the diaphragm, and lead to short-circuit phenomenon. High temperature will make the electrolyte decomposition turn into gas, carbon negative electrode and the diaphragm paper will burn. When the internal pressure is too large, battery shell is unable to withstand the pressure, and then battery will explode.

The moisture content is too high

Can water and electrolyte in the cell reaction, gas production, charging, lithium reactions can be generated and generate lithium oxide, make batteries capacity loss, easy to make batteries overcharge and gas production, water with low breakdown voltage, charging is easy to decompose generated gas, when the series of the generated gas can make the batteries of internal pressure, when batteries shell cannot afford, batteries would explode.

Internal short circuit

Due to internal short circuit phenomenon, batteries, large current discharge, produce a large amount of heat, burn the diaphragm, bigger short-circuit phenomenon, caused by such batteries can produce high temperature, the electrolyte decomposition into gas, the internal pressure is too large, when batteries shell unable to withstand the pressure, batteries would explode.

The upper gum

Laser welding, the heat conduction to the anode ear on the shell, make the positive ear temperature is high, the positive and the diaphragm, if there is no separated upper gummed paper hot cathode ear will make diaphragm paper burn out or contraction, causing internal short circuit, and form the explosion.

High temperature tape around the cathode

Customers in the anode ear spot welding, the heat conduction to the anode ear, if high temperature tape is not good, the cathode heat will burn out the diaphragm on the ear, causing internal short circuit, form the explosion.

Stick at the bottom of the glue was not fully cover the bottom

Customers when spot welding in aluminum composite nickel band at the bottom of the place, can produce a large amount of heat in the bottom of the shell wall, at the bottom of the conduction of core, if high temperature tape is not completely cover the diaphragm, can burn the diaphragm, causing internal short circuit, form the explosion.

The overcharge

The positive of lithium batteries charging, excessive release can make the structure change of the positive electrode, and too much of the release of lithium, easy to insert in the negative, also easy to cause the cathode surface lithium, and, when the voltage is 4.5 V, the electrolyte will make a lot of gas decomposition. Above all are likely caused the explosion.

External short circuit

External short circuit may be due to improper operation, or use by mistake, due to external short circuit, the battery discharge current is very big, can make the batteries of fever, high temperature can make the batteries inside the diaphragm shrinkage or mind completely, causing internal short circuit, thus explosion.

Station by the lack of the cathode capacity anode bag not the positive is negative step matching error cathode anode particles were killed negative pressure dew anode pits cathode foil scratches uneven anode coating dark mark the positive head tail uneven stacking the anode coating the positive dressing quantity partial Dazheng negative anode material mixing unevenly low capacity of the positive material capacity high negative capacity is insufficient

Moisture content is too much the location of the sealing is too slow and moisture absorption Chen Huashi moisture absorption water content is too large injection liquid electrolyte before baking not dry or damp assembly baking not drying coating is negative when the positive glue not dry ingredients when moisture absorption the anode baking inadequate water content is too high

Internal short circuit location at the bottom of the stick glue not completely cover the high temperature tape cover the anode ear at the bottom of the upper gum wrong baking at high temperature bake bad diaphragm laser welding short circuit batteries did not check out the assembly micro short circuit batteries mean assembly short circuit batteries did not check out the flattening pressure is too great when the diaphragm paper there are sand holes not neat negative Maohan flat, not have burrs is negative points small burrs are negative to point out the positive and negative lay * * burr dice internal short circuit

Overcharge may be the location of the user when using the charger voltage large testing individual point voltage large current testing set too big batteries capacity lack pre-charge ark individual point when too much current pre-charge current set greater than filling

External users in the use of short circuit may labor protection of circuit board failure is negative when the short circuit batteries in the process of turnover on the lighter batteries for good, is caused by the cathode contact external short circuit

All in all, all the related location control should be strengthened. Security is the most important for the performance. When conflict with other requirements, we should give priority to satisfy the security.

The page contains the contents of the machine translation.