The internal micro-short circuit hazard control of lithium-ion batteries must prevent internal micro-short circuits from many aspects such as single cell design, material selection, and environmental process control. In addition, in order to minimize the influence caused by the internal short circuit of the single cell, so as not to cause a chain reaction, it is necessary to pay attention to the following problems in the design of the battery pack.

1) Single battery overheating isolation device
The single battery overheat isolation device can be used for isolation when the single battery has an internal short circuit or an external force impact, stops the battery pack from charging/forced overdischarge of the failed single battery, and prevents the high temperature, flame, etc. of the failed single battery. Explosives cause interlocking discharges of adjacent single cells, thus playing a role in blocking.

2) Single battery connection measures
Falling off or weak welding of electrical connection measures (such as wires, nickel tapes, fixing screws) of the single cells in the battery pack can cause excessive local resistance, cause high temperatures in the area of ​​the falling point, and cause internal short circuits adjacent to the single cells.

3) Minimize the energy of the single battery
It is generally believed that the greater the energy of a single battery, the less the number of batteries in series and parallel, and the higher the reliability, which is correct from the reliability analysis of series and parallel groups. However, if the energy of the single battery is too large, once the runaway reaction occurs, the destructive power to the battery pack will be greater. In principle, the chain reaction of the entire battery pack will be more likely to occur, resulting in an uncontrollable situation. Therefore, it is very important to choose a suitable single cell energy design.

4) The series-parallel mode of single battery
The series-parallel mode and number of single cells also have a great impact on the internal short circuit and chain reaction of single cells. For example, connecting in series can easily lead to forced discharge of a single battery, and parallel connection can easily lead to forced charging of a single battery, which may cause the internal pressure and current of the single battery to be too large, thereby forming an internal short circuit.