In addition, according to a recent market survey, the frequency of people changing their mobile phones is also decreasing. Even for young people who are more pursuing digital products, the average time for changing a mobile phone has become 3-5 years. The life of mobile phones is getting longer and longer, but the batteries are getting weaker and weaker, so many people have to endure frequent charging times. In fact, the correct charging method can effectively extend the battery life of mobile phones.
The reduction of battery life is actually the reduction of battery capacity. To understand why the battery capacity is reduced, let's first briefly understand the working principle of lithium batteries.
At present, the batteries of mobile phones on the market are basically lithium-ion batteries. Compared with the original Ni-MH and Zn-Mn batteries, lithium-ion batteries have the characteristics of larger capacity, smaller volume and longer service life. Because of this, the development scale of lithium-ion batteries is increasing. Lithium-ion batteries are mainly classified according to cathode materials. At present, the cathode materials used in mobile phone batteries are mainly lithium ferrous phosphate, lithium cobaltate and ternary lithium batteries (including NCA and NCM, namely nickel, cobalt, aluminum or nickel, cobalt and manganese), and the cathode material is mainly graphite.
The charging and discharging process of lithium ion battery is actually the process of lithium ion moving between the anode and the cathode. When discharging, lithium ions will escape from the layered graphite structure, pass through the electrolyte and separator and enter the crystal structure of the positive electrode. The charging process is the opposite. In fact, the charging and discharging of lithium batteries is the continuous embedding and deintercalation between the positive and negative electrodes. Therefore, lithium batteries are also vividly called "rocking chair batteries".
In fact, the battery life of a mobile phone has a great relationship with the integrity of the internal material structure of the battery. The following ways of using mobile phones will gradually affect the battery structure.
1. Overcharge and overdischarge of the battery
The working principle of lithium-ion battery has been introduced above. When charging, lithium ions are deintercalated from the positive electrode and embedded into the graphite layer.
If overcharged, a large number of lithium ions will be embedded in the graphite, destroying the graphite layer, and may crystallize on the surface of the graphite layer, resulting in lithium dendrites. The sharp crystal structure of lithium dendrite may damage the separator between the anode and cathode of the battery and affect the service life of the battery.
On the other hand, a large number of lithium ions are embedded in the cathode crystal material, which will gradually "disintegrate" the cathode crystal structure, so that the number of lithium ions that can enter the cathode material next time will decrease and the battery capacity will decrease.
The same is true of overdischarge. Excessive discharge will also cause irreversible damage to the anode and cathode materials, resulting in a decrease in battery capacity. Therefore, the best way to charge a mobile phone is to charge it lightly. You don't have to wait until there is no electricity. It is best not to charge it for a long time.
Although the battery itself has a battery protection mechanism, that is, when the battery power is low, it will automatically turn off when the battery is fully charged to prevent overcharging and overdischarge. But will the degree of overcharge and overdischarge of the battery itself change with the change of battery capacity? Keeping the mobile phone in a low or fully charged state for a long time may also damage the battery and reduce its capacity, so it is best to keep the battery at 20%-80%.
2. Don't use or charge your mobile phone in cold or overheated conditions.
The normal use temperature of the battery is between 0℃ and 35℃. If the temperature is too low, the fluidity of electrolyte in the battery becomes worse and the voltage drops. If the mobile phone is charged at this time, the negative electrode potential will be too high, which will produce metallic lithium at the negative electrode and reduce the service life of the battery.
If the temperature of the mobile phone is too high, the activity of the internal materials of the battery will be greatly improved, and the material structure will be destroyed and the capacity will be reduced.
So try not to use your mobile phone in cold or overheated conditions, such as playing with your mobile phone while charging.
The above two points are the factors that have great influence on battery health. In daily use, we can also extend the battery life by appropriately reducing the power consumption of mobile phones. For example, the brightness of the screen should not be adjusted too much, the background can be turned off for unused applications, and the battery discharge current can be reduced by reducing the power consumption of the mobile phone, which is also beneficial to battery health.
Now various brands of flagship machine are also very popular. There are thousands or even tens of thousands of mobile phones, and the non-removable battery reduces people's desire to replace the battery. Therefore, when using the mobile phone, we can effectively extend the service life of the battery through the above methods. China's national standards require that the service life of lithium-ion batteries for mobile phones should not be less than 300 cycles, but the actual service life of batteries is much longer than this value, but the specific service life is closely related to our habit of using mobile phones.