Why does 18650 lithium battery have a history of explosion?
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2023/08/21 16:45:47
More than three hundred years ago, Benjamin Franklin began to capture lightning, which opened people's understanding of lightning, but also opened people's understanding of electricity, from that time on, there are many people considering how to capture the electricity for storage, so gradually the battery slowly evolved, as an important invention in history, the emergence of the battery does solve a lot of problems. Greatly improve the efficiency of life and work, and the emergence of lithium batteries makes people more in-depth understanding, 18650 lithium battery is the earliest invention and use of liquid lithium batteries, in many fields can see the use of 18650 lithium batteries, 18650 lithium batteries compared to other nickel-hydrogen-nickel-cadmium batteries have a very obvious advantage, And the reliability is relatively good, and now 18650 lithium batteries have also been used in industrial and large equipment.
It is generally believed that the cutoff voltage of the ternary lithium battery is below 3.0V and that the electricity is used up, (the specific cutoff voltage needs to see the lowest value of the protection board, and there are 2.8V and 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 (generally lithium batteries are used with a protection board, so excessive discharge will also lead to the protection board can not detect the battery voltage, so can not charge the battery normally). 4.2V is the maximum limit voltage of ternary lithium battery, it is generally believed that the voltage of lithium battery is charged to 4.2V, the battery charging process, the battery voltage at 3.7V gradually rises to 4.2V, lithium battery charging can not charge the voltage to 4.2V or more, otherwise the lithium battery is damaged, this is the lithium battery special place, In general, 18650 lithium batteries have the following advantages.
1, wide range of use:
Notebook computers, walkie-talkies, portable household appliances, instruments, audio equipment, toys, cameras, digital products electronic equipment; 2, can be more and more series combined 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 30 milliohm, which greatly reduces the power consumption of the battery, extends the standby time of the mobile phone, and can fully reach the level of international standards. This kind of polymer lithium battery that supports large discharge current is the ideal choice for remote control model toys, and becomes the most promising product to replace nickel-metal hydride battery products.
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 of 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 and no explosion, and after ROHS trademark certification, all kinds of safety performance tests can pass, good high temperature performance, continuous discharge efficiency of 99.9% at 60 degrees high temperature, in order to prevent lithium battery short circuit, lithium battery anode and cathode are separated, so the short-circuit accident rate is minimized. In addition to human destruction, there is no self-short circuit, and a protection board can be installed to avoid overcharge and discharge of the battery, which extends the service life of the battery.
7, long service life, the normal cycle life of 18650 lithium battery can reach more than 600 times (full discharge of a cycle), is more than twice the ordinary dry battery.
8, large capacity, the general capacity of 18650 ternary lithium battery is between 1200mAh-3350mAh, the imported cell may have a larger capacity of several hundred mA, and the same volume of dry batteries 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 and high capacity battery pack.
Why does 18650 lithium battery have a history of explosion?
The vast majority of 18650 lithium batteries use steel shell packaging, the quality of the battery is not protected by the function of the protection board, in the case of overcharge and discharge, it will increase its internal pressure, and it will explode when it exceeds the withstand value. Problems such as short circuit, high temperature or battery extrusion deformation or even puncturing may cause an explosion.
After decades of technological breakthrough innovation, 18650 lithium battery preparation process has been very mature, in addition to the performance greatly improved, its safety performance is also more perfect, in order to avoid the explosion of the sealed metal shell, now 18650 lithium battery will be in the middle of the top cap with a safety valve parts, and is a standard for each battery. This is the most important safe explosion-proof measure for 18650 lithium batteries.
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 electrolyte leaking inside the battery will react chemically with oxygen molecules in the air under high temperature conditions, and there may still be smoke, and now the 18650 lithium battery will be equipped with a protective plate when leaving the factory, its function is to prevent overcharging and over-discharge of the lithium battery, and further improve the safety performance of the battery.
Why did the 18650 lithium battery have a history of explosion? All because unscrupulous manufacturers use unqualified inferior 18650 batteries to save costs, and even caused by second-hand waste electricity. At present, the 18650 lithium batteries produced by major battery manufacturers such as Panasonic, SONY, HONGWELL Battery, Hongwei Energy and so on are actually very safe, and the utilization rate of 18650 batteries is very high.
Summary: For lithium batteries, occasionally 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 energy relatively high battery, its application field is very wide, industry, life have 18650 lithium battery use.
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