In order to prevent the battery from discharging or overcharging due to misuse, a triple protection mechanism is installed in the single lithium-ion battery. The first is to install a relief valve (i.e. the vent hole on the top of the battery). When the internal pressure of the battery reaches a certain value, the safety valve will automatically open to ensure the safety of the battery. The second is to select the appropriate separator material. When the temperature reaches a certain value, when the temperature rises, the micron-sized pores on the separator will automatically dissolve, preventing lithium ions from passing through and the internal reaction of the battery. The third is to use a switching element. As the temperature inside the battery increases, its resistance increases accordingly. When the temperature is too highed, the power supply stops automatically. Many people think that as long as we use lithium batteries correctly when using electronic products such as our portable speakers, that is enough. However, with so many users, it is inevitable that lithium batteries will be misused, causing unnecessary damage. lithium batteries appear. The above three protection mechanisms are installed to solve the problem of battery over-discharge or over-charge.
Why does overdischarging lithium batteries damage the battery?
Pacific Automotive Network Overcharging and overdischarging will damage lithium iron phosphate batteries. Overcharging will cause lithium dendrites, and overdischarging will cause copper dendrites, which will cause lithium batteries to short circuit and malfunction. Problem: thes lithium batteries therefore require superficial charging and discharging. At present, when using lithium batteries, protection circuits should be installed as much as possible to ensure safety. At the same time, lithium iron phosphate battery is a relatively safe type of lithium battery.
When overcharging, the battery voltage increases rapidly with increasing polarization, which will cause irreversible changes in the structure of the positive active material and decomposition of the electrolyte. A large amount of gas will appear and one. A large amount of heat will be released, causing the battery temperature to decrease. The internal pressure increases sharply, and the internal diaphragm melts or shrinks, causing the positive and negative electrode materials to contact and short circuit, causing explosion, combustion and other possible dangers.hey.
Over-discharge: Over-discharge refers to further discharge when the voltage reaches the rated voltage. For example, the rated discharge voltage of a ternary lithium-ion battery is 3.2V if it continues to discharge. when it is less than 3.2V, it is over-discharge. What damage does overdischarging cause to the battery?
Once the battery has discharged the internally stored energy and the voltage has reached a certain value, continued discharge will cause the battery to overdischarge which can have catastrophic consequences for the battery, especially excessive current discharge. Repeated excessive discharge will have a greater impact on the battery. Generally speaking, excessive discharge will increase the internal pressure of the battery, destroy the reversibility of positive and negative active materials, decompose the electrolyte, depositlithium on the negative electrode and will increase the resistance. Even if it is loaded, it can. will only be partially restored, and the capacity will also be significantly attenuated.
One: Use a special protection board (BMS) for lithium-ion batteries to work with the battery. The protection board can protect the battery from overcharging or overdischarging. The smart version can also adjust the charging voltage. and discharge voltage, which can better protect the battery.
Second: Use the corresponding lithium-ion battery charger instead of fast charging.
Three: When the battery voltage reaches the voltage set by the protection board, the protection board cuts off the power to protect the battery, but the lithium-ion battery drops and the voltage rises, which will be a little higher than the voltage set by the protection board. It can no longer beused at the moment. Repeated use will damage the battery causing irreversible damage.
The lifespan of lithium-ion batteries is determined. First of all, there is one objective fact that cannot be changed, and that is the lifespan of a cell phone battery. It is somewhat similar to the human lifespan. People who worry too much can lose years of their life. have good lifestyle habits, they can live for a few more years. The same goes for lithium-ion batteries. If you use them correctly, you can use them for a few more years, but if you mishandle them, their lifespan will be very short. Just like human life, no matter how hard you try, it will eventually end. The same goes for lithium-ion batteries, even if you don't use them, they will age slowly. In addition, it is always an irreversible aging, so if the battery capacity of themobile phone has been lost, there is no way to restore it to the state of the new phone.
The operating principle of lithium-ion batteries is very simple. Charging and discharging are actually chemical reactions inside the battery, regardless of the type, they will undergo the movement of ions from the negative electrode to the positive electrode. or from the positive electrode to the negative electrode, forming positive and negative electrodes. The polar compounds change as the reaction proceeds, and the loss of the battery is actually a decrease in ionic activity.
(Images/Text/Photos: Pacific Automotive Network Q&A)
Excessive charging and discharging of lithium-ion batteries will cause damage permanent at the positive terminals and negative electrodes.
Excessive discharge causes the carbon sheet structure of the negative electrode of the battery to collapselithium battery, and collapse will prevent lithium ions from being inserted during the lithium battery charging process, and overcharging the lithium battery will result in too much lithium ion; be integrated into the carbon structure of the negative electrode. As a result, some lithium ions can no longer be released, which will damage the lithium battery.
Detailed information:
The final discharge voltage of the lithium-ion battery is of 2.75 V. ~ 3.0 V (domestic battery manufacturers indicate the operating voltage range or final discharge voltage. Each parameter is slightly different, generally 3.0 ~ 2.75 V, and the phosphor iron is 2.5 V.).
Continuing to discharge below 2.5V (iron phosphor 2.0V) is called overdischarge (the international standard is a minimum of 3.2V, iron phosphor 2.8V at low voltage or self-reactiondischarge will cause lithium). ions Active substances are broken down and destroyed and are not necessarily restored. Any form of overcharging lithium-ion batteries will result in serious damage to battery performance or even an explosion.
Baidu Encyclopedia-Lithium Battery