Why does 18650 lithium battery have explosion history
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2023/05/25 11:26:45
More than three hundred years ago, Benjamin Franklin started to capture lightning, which opened people's understanding of lightning, and also opened people's understanding of electricity. Since then, many people have been thinking about how to store the captured electricity, so gradually the battery evolved. As an important invention in history, the emergence of battery has indeed solved many problems. It greatly improves the efficiency of life and work, and the appearance of lithium battery further deepens people's understanding. 18650 lithium battery is the first liquid lithium battery invented and used so far. 18650 lithium battery can be seen in many fields, and it has obvious advantages compared with other nickel-hydrogen-nickel-cadmium batteries. And the reliability is relatively good, now 18650 lithium battery has also been used in industrial and large equipment.
It is generally believed that the cut-off voltage of the three-way lithium battery is below 3.0V and that the electricity is used up, (the specific cut-off voltage needs to see the lowest value of the protection plate, also to 2.8V,2.75V). Most of the lithium battery discharge can not be lower than the set cut-off voltage, otherwise continue to discharge will cause excessive discharge damage to the battery (lithium batteries are generally used with a protective plate, so excessive discharge will also lead to the protection plate can not detect the battery voltage, so that the battery can not be charged normally). 4.2V is the highest limit voltage of ternary lithium battery, it is generally believed that the lithium battery voltage charged to 4.2V is considered full, in the process of battery charging, the battery voltage gradually rises from 3.7V to 4.2V, lithium battery charging should not charge the voltage above 4.2V, otherwise it will damage lithium battery, which is the special place of lithium battery. Generally speaking, 18650 lithium battery has the following advantages.
1. Wide range of use:
Notebook computers, walkie-talkies, portable household appliances, instrumentation, audio equipment, toys, video cameras, digital products and electronic equipment; 2, can be multi and multi series combination into different capacity, voltage lithium battery pack; 3, lithium battery internal resistance is small:
The internal resistance of the polymer cell is small, and the internal resistance of the domestic polymer cell can even be less than 30 milliohm, which greatly reduces the self-consumption of the battery and prolonging the standby time of the mobile phone, which can fully reach the level of international standards. Lithium-ion batteries, which support high discharge currents, are ideal for remote control model toys and are the most promising alternative to NIMH batteries.
4, no memory effect, do not have to empty the remaining power before charging, easy to use; 5, high voltage, 18650 ternary lithium battery voltage is 3.7V nominal voltage, much higher than the nickel-hydrogen-nickel-cadmium battery voltage of 1.2V; 6, high safety performance, 18650 lithium battery non-toxic environmental protection, no fire no explosion, and after ROHS trademark certification, all kinds of safety performance tests can pass, high temperature performance is good, at 60 degrees high temperature continuous discharge efficiency of 99.9%, in order to prevent lithium battery short circuit, lithium battery anode and cathode are separated, so short circuit accident rate to the lowest, In addition to artificial damage does not exist short circuit, can be installed to avoid battery overcharge and discharge, so as to extend the battery life.
7, long service life, the normal cycle life of 18650 lithium battery can reach more than 600 times (full of a cycle), is more than twice the ordinary dry battery.
8, large capacity, 18650 terre lithium battery general capacity of 1200mAh-3350mAh, the imported cell may be a few hundred milliamps larger capacity, and the same volume of dry battery only lithium battery capacity is generally about, the lithium battery more and more string combination, the 18650 lithium battery can be combined into a high voltage high capacity battery pack.
Why does 18650 lithium battery have explosion history?
The vast majority of 18650 lithium batteries use steel shell packaging, the quality of the battery because there is no protection plate function protection, in the case of overcharge and release, will make its internal pressure increase, when more than the bearing value will explode. Short circuit, high temperature or battery extrusion deformation or even puncturing problems can cause an explosion.
After decades of technological breakthrough and innovation, the preparation process of 18650 lithium battery has been very mature. In addition to the great improvement in performance, its safety performance is also more perfect. In order to avoid the explosion of the sealed metal shell, 18650 lithium battery is equipped with a safety valve part in the middle of the top cap of the positive electrode, and it is a standard part for every battery. This is as 18650 lithium battery as the most important safety and explosion-proof effective measures.
When the internal pressure of the battery is too large, the safety valve of the positive cap will be opened for exhaust decompression due to the internal and external pressure difference, to avoid explosion accidents. However, when the safety valve is opened, the battery internal leakage electrolyte will be under high temperature conditions and oxygen molecules in the air chemical reaction, still may appear smoke phenomenon, and now 18650 lithium battery in the factory will have a protective plate, its function is to prevent lithium battery overcharging and excessive discharge, further improve the safety performance of the battery.
Why has 18650 lithium battery exploded before? All because unscrupulous manufacturers in order to save costs to use substandard substandard 18650 batteries, or even second-hand waste electricity caused. At present, the 18650 lithium battery produced by major battery manufacturers such as Panasonic, SONY, HONGWELL Battery, Hongwei Energy, etc., is actually very safe, and the utilization rate of 18650 battery is very high.
Summary: For lithium batteries, the occasional smoke is understandable, a few years ago lithium battery technology on the internal polar chemical reaction stability is not very stable, decades later the technology is relatively mature, 18650 lithium battery as a cost-effective and relatively high energy battery, its application field is very wide, industry, life have 18650 lithium battery use.
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