Frequently Asked Questions on the Use and Maintenance of Lithium Battery

1, lithium ion battery basic concept:

Lithium-ion batteries have a nominal voltage of 3.7 V(3.6 V) and a charging cut-off voltage of 4.2 V(4.1 V, with different designs according to the brand of the core). (The lithium ion core specification is: lithium ion secondary battery

2, charging requirements for lithium ion batteries(GB/T182872000 specification)

First, constant current charging, that is, the current is certain, 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 charging is changed to constant voltage charging, that is, the voltage is certain, and the current is based on the saturation degree of the core. As the charging process continues to decrease, when it is reduced to 0.01 C, the charging is considered to be terminated. (C is a representation of the current controlled by the battery nominal capacity. For example, the battery is the capacity of 1000 mAh, 1C is the charging current 1000 mA, note that mA is not mAh, and 0.01 C is 10 mA. ) Of course, the specification is represented by 0.01 C5A, which is simplified here.

3, why do you think 0.01 C is the end of charging?

This is stipulated by the national standard GB/T18287-2000 and is also discussed. 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. (Batteries of no problem quality should reach 0.01 C within 8 hours. Batteries of poor quality are meaningless to wait.)

4, how to distinguish the battery is 4.1 V or 4.2 V?

Consumers can not be distinguished, this is to see the core manufacturer's product specifications. Some brands of cores are 4.1 V and 4.2 V common, such as A& TB(Toshiba), domestic manufacturers are basically 4.2 V, but there are exceptions, such as Tianjin lishen is 4.1 V(but currently it is also 4.2 V).

What happens if you charge the 4.1 V core to 4.2 V?

It will increase the battery capacity, feel good to use, and increase the standby time, but it will shorten the battery's service life. For example, the original 500 times, reduced to 300 times. Similarly, overcharging the 4.2 V core will also reduce the life span. Lithium-ion core is very delicate.

Since there is a protective plate in the battery, can we rest assured

No, because the cutoff parameter of the protective plate is 4.35 V(this is still good, the difference is 4.4 to 4.5 V), the protective plate is to cope with the contingency, if each time overcharge, the battery will quickly decay.

How much charge current is appropriate?

In theory, the smaller the battery, the better. But you can't wait three days to charge a battery. The low rate of charging stipulated by the national standard is 0.2 C(arbitration charging system), and the above 1000mAh capacity battery is 200mA, so we can estimate that this battery can be filled for more than 5 hours. (capacity mAh = current mA × time H).

The National technical supervision department identified lithium capacity, which was charged at a high rate of 1C and discharged at a low rate of 0.2 C. The capacity value was calculated in time. The number of tests was 5 times, and 1 capacity reached the end of the test. (That is, there are 5 opportunities. If the first test is qualified, the next 4 are not done.) Before the test, there is allowed a pre-cycle, that is, charging to 4.2 V with a constant current of 1C, which stops without a subsequent constant pressure of 0.01 C. The process is not 14 hours.

8, lithium-ion battery can withstand how much charging current?

The factory test can be very high, but the national standard has a high doubling rate of 1C. Take the above battery as an example, it can be filled for more than 1 hour. Can the battery withstand such a large charge current? For the current lithium ion core, it is small.

There is currently no national standard for chargers. The implementation is the Ministry of Posts and Telecommunications industry standard YD/T9981999/2, which stipulates that the current of chargers must not be greater than 1C.

How is life span defined?

In simple terms, it means that after the battery has been charged with N 1C and discharged 1C, the capacity has dropped to 70 %. At this time, N is the life span. It's not like 300 is still working, and 301 isn't working. The national standard stipulates a life span of not less than 300 times. When the conditions we use are not tested, the life span will be longer.

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