What is the reason why the power lithium-ion battery will burn or explode?

Tác giả ：Iflowpower – Добављач преносних електрана

The explosion is a more common hazard performance of the dynamic lithium-ion battery system, which is also more serious, not only cause property damage and environmental damage, or even cause personal injury or life. It may be protected by the power lithium-ion battery system to combust or explode: a power lithium-ion battery (battery cell) is thermally out of control, an electrolyte and other flammable substances; high voltage circuit of the power lithium-ion battery system The middle local part is too large, and there is a large current flowing out of the temperature rise to the temperature of the fire point temperature, the flammable substance inside the dynamic lithium-ion battery system; the exterior of the dynamic lithium-ion battery system, resulting in the internal temperature of the power lithium-ion battery system Continue to rise, reach the temperature of the fire point, ignite the internal combustible substance. Decomposing the use of electric vehicles, the first case is high, the risk factor is also high, and the electrical discharge side reaction causes thermal out of control to burn or explode, the dynamic lithium-ion battery system.

The inside of the lithium-ion battery has a method of exothermic reactions: ESI film analysis, temperature range is 90 ~ 120 ¡ã C; the reaction of the negative electrode and the electrolyte, the temperature reaches 120 ¡ã C; the electrolyte analysis, the temperature is approximately about 200 ¡ã C; positive and electrolysis The reaction of the liquid is accompanied by positive electrode, and the temperature ranges from 180 to 500 ¡ã C; the negative electrode and the adhesive reaction, about 240 degrees or more. The fundamental of the battery heat (burning, explosion) is the radical side reaction in the electrical core leads to heat accumulation. The rate of the electrical core is less than the heat accumulation rate, the temperature continues to rise, and the pen is straight to the fire point temperature, causing combustion and explode.

The heat inside the battery core follows the energy conservation: QP = QA + QA formula Qp is the heat of various negative reactions inside the cell, QE is the heat exchanged in the battery and the environment, that is, heat dissipation, QA is telecommunications self-absorption Thermal and thermal accumulation. If QE<000000>ge;The QA is that QA is a negative value or zero. The internal temperature does not rise, and there is no thermal out-of-control; if the decomposition from above can be seen from the above decomposition, if it is not possible to block the thermal side reacts inside the battery core, the interior of the telecommunications The temperature will continue to rise until the occurrence of thermal out-of control incidents, to reduce the risk of accidents, the measures that can be taken are: take protection measures, reduce the probability of occurrence of external bursts (such as overcharge, over, overheating, short circuit, squeeze , Puncture, etc.

); blocking the positive feedback process of the exothermic side, such as the PACK module is using a bonded fuse process, or adding a PTC material between the positive and negative material and the current fluid; reducing the depth If the heat of the occurrence of lithium iron phosphate positive material, the organic solvent component of the electrolyte is changed; improve the fire point temperature, such as adding a flame retardant material in the electrolyte, select a ceramic diaphragm, etc., improve heat dissipation ability, alert heat accumulation, force The Long battery uses an efficient liquid-cold design method, and there is also an individual approach to immersing the entire battery in the coolant. The above, the summary of the thermal out-of-control mechanism and prevention measures have been practiced in the battery full battery design, manufacturing, but for different chemical properties for different material systems, the electrical cell thermal out-of control mechanism is different, different System design also leads to system-level dangers and treatment measu.