Lithium Battery Charging And Discharging

- Jul 07, 2017-

Lithium battery is a historical concept, the early lithium battery is a lithium manganese battery, lithium battery discharge redox reaction, discharge process is a primary battery reaction characteristics. Later, the lithium ion battery, its reaction principle and lithium manganese battery is completely different, but people are used to the lithium ion battery is called "lithium battery" in the frequency of use but far more than the lithium manganese batteries, the original meaning of the result, we will focus on the lithium ion battery sense analysis of lithium battery charge and discharge.

Based on the original lithium metal battery, the invention of the first Sony Corp to carbon materials as the anode and cathode of lithium battery lithium containing compounds, the process of charge and discharge only lithium ions, this is not a lithium metal, lithium ion battery, lithium battery is the title of the people.

First, we discuss the problem of rechargeable lithium batteries, lithium battery charging problem mainly relates to a lithium battery charging method and lithium battery is fully charged the judgment, the two problems of how to charge lithium batteries in a text has been detailed, here I just bring a rough. Lithium battery charging process is divided into two steps: constant current charging process + constant voltage charging process, where the constant current charging process accounts for most of the charging time, constant voltage charging is just a process of charging. In the charging process should pay attention to occurrence of excessive charging of lithium battery, lithium battery charger standard will be based on the characteristics of lithium battery charging to set a good program, there are not too often in the group with lithium battery protection board, could prevent excessive charging of lithium battery.

Lithium battery charging current and charging voltage is lithium battery charging in the two most important parameters, it is not only related to the performance of lithium batteries is also related to the safety of lithium batteries, high current or high voltage charging will affect the performance of lithium batteries, or a fire explosion and other dangerous situations occur, so to lithium the battery should pay attention to when the charging voltage and the charging current, it will choose a lithium battery charger, single lithium battery charging voltage is 4.2V, lithium battery charging voltage =4.2* lithium battery serial number, such as 3 series lithium battery charge voltage is 4.2*3=12.6V; considering the charging time should not be too long, usually rechargeable lithium batteries the current is set to 0.5C.

The use of lithium batteries is the process of lithium battery discharge. At this time, lithium ion becomes negative carbon layer, moving back to the cathode, the lithium ion more back to the cathode, the discharge capacity is high, the lithium battery capacity usually refers to the lithium battery discharge capacity at 0.2C rate discharge system. Lithium battery discharge is the reverse movement of the charging process, because the charge and discharge performance of lithium ion in the positive and negative reciprocating motion between the poles, so the lithium battery is also known as rocking chair batteries.

The discharge of the lithium battery is accompanied by the decline of the battery voltage, if the use of small current discharge, the discharge time is long, the voltage drop is slow; if the use of large current discharge, the voltage drops quickly, the discharge time is short. From the total output power point of view, a lithium battery using small current discharge ratio of the use of large current discharge capacity to be large, the reason is that the resistance is also large current.

The IEC standard provides a lithium battery discharge current of 0.2C, which is because the shallow charge and discharge can better play the lithium battery performance. The actual use of the lithium battery discharge current can be adjusted according to the actual needs and the status of the battery pack, such as lithium batteries, the discharge current can be set higher.

In addition, attention should be paid to the lithium battery discharge voltage, the lithium battery discharge termination voltage, the battery is the ideal cut-off voltage is 3, but the actual use of the lithium battery discharge cut-off voltage settings will be different, usually lower than 3.0V, the purpose is to make full use of battery power, and the most common will discharge termination voltage is set to 2.75V. When the battery discharge to the termination voltage to charge the battery, if at the end of discharge voltage below the battery will continue to cause lithium battery over discharge, over discharge will affect the performance of lithium batteries, even irreversible capacity loss. Fortunately, lithium batteries are now added to the protection board, can prevent the occurrence of excessive discharge of lithium batteries, lithium battery protection performance.