Working Principle and Recharging Requirements of Lithium Battery

Most mobile phones today use lithium batteries or lithium polymer batteries. It is a battery made of lithium metal or lithium alloy as a negative electrode material and uses a non-aqueous electrolyte solution. The earliest lithium batteries came from the great inventor Edison. Due to the very lively chemical properties of lithium metals, the processing, preservation, and use of lithium metals require very high environmental requirements. Therefore, lithium batteries have not been used for a long time.

With the development of Microelectronics technology in the 20th century, miniaturized equipment has been increasing, and it has put forward high requirements for power supply. Lithium batteries have then entered a large-scale practical phase, especially in mobile phone battery applications, and the commonly used lithium ion core specification for mobile phones is: lithium ion secondary batteries. At present, the commonly used mobile phone lithium-ion battery has a nominal voltage of 3.7 V(or 3.6 V) and a charging cut-off voltage of 4.2 V(or 4.1 V, with different designs according to the brand of the core).

The charge requirement for lithium-ion batteries(GB/T182872000 specification) is first of all a constant current charge, that is, a certain current, and the battery voltage gradually increases with the charging process. When the battery end voltage reaches 4.2 V(4.1 V), the constant current charge is changed to constant voltage charging. That is, the voltage is certain, According to the saturation degree of the core, the current decreases gradually as the charging process continues. When it decreases to 0.01 C, the charging is considered to be terminated. Note that C is a representation of the current against the nominal capacity of the battery. For example, the battery is the capacity of 1000mAh, 1C is the charging current 1000mA, note that mA is not mAh, and 0.01 C is 10mA. Of course, the specification is expressed as 0.01 C5A.

Then why do you think 0.01 C is the end of the charge, which is actually stipulated by the national standard GB/T18287-2000. In the past, everyone generally ended with 20mA. The standard YD/T998-1999 of the Ministry of Posts and Telecommunications also stipulated that no matter how large the battery capacity is, the stop current is 20mA. The 0.01 C stipulated by the national standard helps to charge more fully and is beneficial to the manufacturer's certification.

In addition, the national standard stipulates that the charging time should not exceed 8 hours, that is, even if it has not reached 0.01 C, 8 hours is considered to be the end of the charging. Because the quality of the battery is no problem, it should reach 0.01 C within 8 hours, and the poor quality of the battery is meaningless. So, remind everyone that charging for more than 8 hours is good for battery life.

The page contains the contents of the machine translation.