Lithium metal will violently oxidize with oxygen when exposed to air and explode. In order to improve safety and voltage, graphite and lithium cobalt oxide are used to store lithium atoms. The molecular structure of these materials forms nano-level small storage Lattice, even if the battery case is broken and oxygen enters, it will not be able to enter these small storage cells because the oxygen molecules are too large, so that lithium atoms will not come into contact with oxygen to avoid explosion. This principle of lithium batteries allows people to achieve high capacity density while also achieving safety.

When the lithium battery is charged, the lithium atoms of the positive electrode will lose electrons and oxidize to lithium ions. The lithium ions swim through the electrolyte to the negative electrode, enter the storage cell of the negative electrode and obtain an electron to be reduced to lithium atoms; the entire procedure is reversed during discharge. In order to prevent the positive and negative electrodes of the battery from directly touching and short-circuiting, a separator paper with many pores will be added to the battery to prevent short circuit. A good separator paper can also automatically close the pores to allow lithium when the battery temperature is too high Ions cannot pass through to prevent danger.

The protection of lithium batteries should include: upper limit of charging voltage, lower limit of discharging voltage, and upper limit of current. In addition to the lithium battery core, there will be a protection board in the general lithium battery pack. This protection board mainly provides these three protections. However, these three protections of the protection board are obviously not enough. Global lithium battery explosions are still frequent. To ensure the safety of the battery system, the cause of the battery explosion must be analyzed more carefully.

Methods to prevent lithium battery explosion

One is to start from the inside of the battery, and the other is external control. The internal protection method is to use PE or PP plastic material as a separation film to separate the positive electrode and the negative electrode. When the battery is overheated, the tiny pores of the separation film will shrink, blocking ions from entering and exiting the positive and negative electrodes; Risk of battery overheating. However, the SONY incident proved that these two methods are not effective, and the industry urgently needs new technologies to protect lithium batteries.