Are lithium batteries more likely to explode
Are lithium batteries more likely to explode? Lithium batteries have been developed for more than several decades since their birth. -in lithium batteries. We often see news about cell phone explosions, so is there a good chance that lithium batteries will explode? Let's find the answer together.
Are lithium batteries more likely to explode? 1As long as it is a lithium battery, there is a risk of explosion, but the probability of this risk is very small. But once it explodes, the explosion power of a larger capacity lithium battery is unimaginable.
There are two important causes of lithium battery explosion, one is short circuit and the other is overcharge. A short circuit is easy to understand, that is, the boPositive and negative terminals of the battery are in direct contact. First, the heat generated by a short circuit in a small area over a normal short period of time is actually very small and will not cause thermal runaway. The battery core itself is designed with an explosion-proof valve, which means that when the internal pressure of the battery core exceeds a certain value, the explosion-proof valve will open and the heat will dissipate quickly. The second is that normally used battery charging equipment is protected against overload and stops charging when the battery voltage reaches a certain value. The third battery cell case itself is a very protective steel shell.
How powerful is the explosion of lithium batteries?
Calculate, a 2.6Ah ternary 18650 lithium battery fully chargedrged has a charge of 2.6* 3.65* 3.6 = 34.164 kilojoules of energy. The energy generated when the muzzle of a general gun is fired is approximately 2.2 kilojoules, which is equivalent to the work done when a force of 1 Newton moves an object 1 meter in the direction of the force. meters from the gun, can easily kill enemies. Think about it, a Tesla requires more than 7,000 3.4 Ah 18650 model lithium batteries.
A 50AH battery with an aluminum alloy case and a size of 20*120*300 ( mm) and lithium manganate as a positive cell exploded during a load test: the 3 meter high roof was blackened. , a hole was dug in the wall about half a meter from the battery (I forget if the wall was brick or sandwich panel), and the door and window panes were shattered. Fortunately, there was no one there at the time of the explosion.
Therefore, lithium batteries pose a fire risk,explosion and combustion. Do not refill, disassemble, squeeze, heat above 212°F or incinerate.
Causes of explosions and fires of lithium batteries
1. Insufficient capacity of the negative electrode of lithium batteries
When lithium When the capacity of the negative electrode of the positive electrode of the battery is insufficient, the lithium atoms generated during charging cannot be inserted into the graphite interlayer structure of the negative electrode and will precipitate on the surface of the negative. electrode to form crystals. Long-term crystal formation in lithium batteries will cause short circuits. At this time, the battery cells will discharge quickly, generating a large amount of heat and burning the separators. High temperature will cause the electrolyte to decompose. It decomposes into gas when the pression is too high, the battery core will explode.
2. The water content is too high
During charging, water may react with lithium to generate lithium oxide , which will result in battery capacity. to be lost. It is easy to overcharge the battery core and generate gas. The decomposition voltage of water is low. It is easy to decompose to generate gas during charging. When this series of gases generated increases the internal pressure of the battery core. , the battery core shell cannot withstand it, the battery core will explode.
3. Internal short circuit
The internal short circuit of the cell causes a significant current discharge, generates a large amount of heat and burns the diaphragm. If a larger short circuit occurs, the electrolyte will decompose into gas and if the internal pressure is too high, the nbattery core will explode.
4. Overcharging of lithium batteries
When the battery is overcharged, excessive release of lithium from the positive electrode will cause the structure of the positive electrode. change, and the excess released lithium may easily not be inserted into the negative electrode and may easily cause lithium to precipitate on the surface of the negative electrode. Additionally, when the voltage reaches more than 4.5V, the electrolyte will decompose. produce a large amount of gas. All of the above can cause an explosion.
5. External short circuit
External short circuit can be caused by poor connection of positive and negative poles due to short circuit external. , the battery discharge current is very large, which will cause the battery to malfunction. The heat and high temperature of the core will cause the core to shrink orcomplete damage to the diaphragm inside the battery core, causing an internal short circuit and therefore an explosion.
Is there a high risk of a lithium battery exploding? 2What is the risk of a ternary lithium battery exploding
The risk is quite high. When. the battery cell is overcharged, the positive electrode contains too much lithium. The release will change the structure of the positive electrode, and too much released lithium can easily not be inserted into the negative electrode, and it will also easily cause lithium precipitation. on the surface of the negative electrode. In addition, when the voltage exceeds 4.5 V, the electrolyte decomposes to produce a large amount of gas. All of the above can cause an explosion. The warning sign of an explosion is deformation due to the heat generated during charging. The harmful consequences can be a short circuitit, an open circuit or even an explosion.
Ternary lithium battery or 18650 lithium battery Which is more powerful in the event of an explosion
< p> Lithium battery After all, it's just a battery, not a bomb. Even 18650 lithium battery has the worst safety and slow discharge performance. At most, it burns violently after bursting. a little noise when bursting. The final conclusion was that even if 2,000 to 3,000 lithium batteries were stacked together, the force of the explosion would still be limited and would hardly kill them. Therefore, in daily life, you should be careful when using equipment equipped with 18650 lithium batteries.The preparation process of lithium batteries is very mature. In addition to greatly improved performance, its security is also very complete. In order to prevent the explosion of the metal casingsealed, a safety valve is installed on the top of the 18650 battery. This is the standard configuration of every 18650 battery and is also the most important explosion-proof barrier. When the internal pressure of the battery is too high, the safety valve on the top of the battery opens the exhaust and pressure reduction function to prevent explosion.
However, many issues remain regarding the safety of ternary lithium batteries. During a car accident, external impact may damage the battery diaphragm, causing a short circuit. The heat released during the short circuit will heat the battery and increase its temperature to over 300°C. Ternary lithium batteries have poor thermal stability. Oxygen molecules decompose when the temperature is below 300°C. When exposed to flammable electrolyte and macarbonaceous materials of the battery, the heat generated further intensifies the decomposition of the positive electrode. shortly it will burn inside.
In comparison, another widely used lithium iron phosphate battery can be maintained at 700-800°C without decomposing oxygen molecules and is safer.
Explosion-proof box.
1. Explosion-proof lithium battery cases can effectively prevent lithium batteries from exploding or catching fire during charging or use, while explosion-proof bags can only prevent it.
2. Explosion-proof boxes for lithium batteries can work in different environmental conditions, including high temperature, low temperature, high humidity, etc., while explosion-proof bags will be destroyed in bad weather.