How powerful is the explosion of Tesla's ternary lithium battery pack? The binder, conductive agent, and electrode active material of the ternary lithium battery pack have a low ignition point, and they are easily ignited when they are improperly operated. After thermal runaway, the explosion limit range of the pyrolysis gas is larger than that of common hydrocarbon gases. Moreover, the amount of gas released by a single-cell lithium battery thermally out of control can reach the lower explosive limit, resulting in a violent combustion explosion.
How powerful is the explosion of the Tesla ternary lithium battery pack?
In the early morning of November 3, 2016, a serious accident occurred in a Tesla ModelS electric car, which caused the entire vehicle to burn. At that time, the ModelS car slammed into a big tree, and sparks were quickly generated, causing the lithium battery pack in the car to explode, which in turn caused the entire vehicle to burn into a huge fireball. After the ternary lithium battery in the car crashed into a big tree, the flames that were produced quickly rushed to the sky, which was a firework.
Why did Tesla hit it as soon as it hits? The super battery, which is known for its high energy density, may be backed up. The higher the battery energy density, the more power stored per unit volume, and the longer the vehicle's cruising range. The ternary lithium battery pack is unique in the world with a battery energy density of 300Wh/kg.
However, the ternary lithium battery pack is very unreliable in terms of safety. In a car accident, an external impact will damage the battery diaphragm and cause a short circuit. The heat emitted during a short circuit will cause the battery to run out of thermal control and quickly increase the temperature above 300°C.
The thermal stability of the ternary lithium battery pack is poor. It will decompose oxygen molecules if it is held at less than 300°C. It will be a little bit after encountering the combustible electrolyte and carbon materials in the battery. The heat generated will further aggravate the decomposition of the positive electrode. It will explode within a short time. In contrast, another widely used lithium iron phosphate battery can last up to 700-800°C without decomposing oxygen molecules and is much safer.
It is precisely based on safety considerations that in China, passenger cars equipped with ternary lithium batteries were once unable to enter the Ministry of Industry and Information Technology's recommended new energy vehicle catalog. There are many defects in the ternary lithium battery pack, and the safety issue is very worrying. Whether in terms of chemical structure or battery structure, ternary materials are very easy to generate heat. If the heat cannot be conducted in time, the battery may explode.
After the ternary lithium battery pack is out of control, the heat releases quickly, and 70% of the energy inside the lithium battery can be released within 1 minute. The flame temperature is high or rapid, and the flame formed by the battery cell will be ejected from the positive electrode, causing the surrounding battery to run out of control. The chain reaction caused the fire to quickly enter the violent combustion stage after the fire broke out. Flames above 800°C (about 400°C for conventional gasoline vehicles) are very easy to ignite car interiors or other parts, and the battery is spread on the chassis of the vehicle, which is widely distributed and has a large impact.
Tesla ternary lithium battery is difficult to extinguish. When the thermal runaway of lithium battery is generally accompanied by a large amount of white smoke, high temperature, low visibility and a large amount of corrosive gas, it makes it difficult for firefighters to carry out fire fighting. In addition, since the internal components of the battery provide combustibles and oxidants, conventional fire extinguishing agents such as dry powder and foam are basically unable to extinguish battery fires.
To solve this problem of easy decomposition and deflagration of ternary lithium battery packs, one is physical pressure relief, and the other is the oxide layer, which increases the decomposition temperature of the cathode material, which can give the pressure relief valve sufficient time to rupture and fully release the pressure , So that it will not burst into flames instantly.
