Reasons and precautions for lithium battery pack fire _ Shenzhen DeAnda Technology

At present, various consumer electronics products represented by mobile phones, power banks, and new energy vehicles all use lithium battery devices. Lithium batteries are the direction of future new energy development. In recent years, some electronic factories have experienced frequent fires and explosions, and the safety of lithium batteries has become the most concerned issue for consumers.

Here are the five main reasons for lithium battery fires:

One External short circuit

External short circuits may be caused by improper operation or misuse. Due to external short circuits, the battery discharge current is high, which can cause the iron core to heat up. High temperatures can cause the diaphragm inside the iron core to contract or completely break, resulting in internal short circuits and causing fires.

II Internal short circuit

Due to the internal short circuit phenomenon, the high current discharge of the battery cell generates a large amount of heat, burning the diaphragm and causing a significant short circuit, resulting in high temperature and decomposition of the electrolyte into gas, leading to excessive internal pressure. When the shell of the core cannot withstand this pressure, the core will catch fire.

III Overcharging

When the iron core is overcharged, the excessive release of lithium from the positive electrode will change the structure of the positive electrode. Excessive lithium is easily inserted into the negative electrode and can also cause lithium to precipitate on the negative electrode surface. When the voltage exceeds 4.5V, the electrolyte decomposes and produces a large amount of gas. All of these can cause fires.

4 Excessive moisture content

Water can react with electrolytes in the core to generate gas. When charging, it can react with the generated lithium to produce lithium oxide, causing a loss of core capacity and easily leading to overcharging and gas generation in the core. The decomposition voltage of water is low, and it is easy to decompose into gas during charging. When these gases are generated, the internal pressure of the core will increase, and when the outer shell of the core cannot withstand these gases. At that time, the core will explode.

Five Insufficient negative electrode capacity

When the capacity of the negative electrode relative to the positive electrode is insufficient, or there is no capacity at all, some or all of the lithium generated during charging cannot be inserted into the interlayer structure of the negative electrode graphite and will deposit on the surface of the negative electrode. The protruding "dendrites" are more likely to cause lithium precipitation during the next charge. After dozens to hundreds of cycles of charging and discharging, the "dendrites" will grow and eventually pierce the diaphragm paper, causing an internal short circuit.

How to make lithium-ion batteries safer?

1. Do not attempt to modify the battery

2. During the charging process, overcharging or excessive emissions should not be allowed

3. Use the original charger.

4. Use reliable batteries

5. Do not place batteries in extreme environments (except for some special batteries). High temperatures, collisions, and other factors are important causes of battery explosions. Try to keep the battery in a stable environment and away from high temperatures.

In addition to paying attention to the usage details of lithium batteries, the safety design and material safety of lithium batteries are also key factors in ensuring their safety.