What is the relationship between voltage and capacity of lithium battery

Lithium-ion batteries have a very useful feature for electricity metering. When discharging, the battery voltage gradually decreases with the passage of electricity, and there is a considerable slope. This provides us with another approximate method of electricity metering, the method of taking the battery voltage. It is as if measuring the water level in the water tank can roughly estimate the amount of water remaining. But in fact the voltage of the lithium battery is much more complicated than the calm water level measurement inside the tank. Using voltage to estimate the remaining capacity of the battery has the following instability: the same battery, in the case of the same remaining capacity, the voltage value changes due to the magnitude of the discharge current. The higher the discharge current, the lower the voltage is. In the absence of current, the voltage is the highest; the influence of ambient temperature on the battery voltage, the lower the temperature, the lower the battery voltage of the same capacity; the influence of the cycle on the battery discharge platform, as the cycle progresses, the discharge platform of the lithium ion battery tends to Deteriorating. The discharge platform is lowered. Therefore, the capacity represented by the same voltage also changes accordingly; different manufacturers, different capacity lithium-ion batteries, the discharge platform is slightly different.

Lithium-ion batteries of different types of electrode materials have large differences in discharge platforms. Cobalt lithium discharge platform and manganese lithium battery is completely different. All of these will cause voltage fluctuations and voltage differences, making the battery capacity display unstable. When using a voltage to measure the battery capacity on a mobile phone, it is impossible for the mobile phone to remain in a standby state with a small current. Temporary loss of high current, such as turning on the backlight, ringing the ring, especially through, will cause the battery voltage to drop quickly. At this point, the capacity displayed by the phone is reduced more than the actual capacity. When the large current is removed, the voltage of the battery will rise. This will cause the unreasonable phenomenon that the capacity display of the mobile phone will rise instead.

The voltage of the battery has been decreasing during the discharge process. For example, the capacity of the battery 3.6v, 19ah, 19ah is not put to 0v, but 2. or 3. When the discharge capacity is 19ah, if it is put into 0v, the capacity will be 19 A little more, if it is over-discharged, it will damage the battery life.

If the design is excellent, the cut-off voltage of the meter and the voltage of the battery are basically the same. When the voltage reaches a certain value, such as 3V, the battery is discharged, or when the battery is almost discharged, the meter will reach the lowest working voltage. The minimum working voltage is relatively high. For example, if it is lower than 3.6v, it will not work. Then there is a situation where the battery still has electricity and the meter cannot work. In this case, the external power supply voltage should be increased.

Different materials and different shapes of batteries to be calculated are different! Lithium cobaltate

Charging voltage 3.7V3.8V3.85V3.9V3.95V

Charge capacity 7.8%28.0%53.0%59.1%67.6%

In general, the higher the charge and discharge voltage of a lithium battery, the greater its capacity. The charge and discharge voltages of lithium batteries of different materials are different. The lowest is lithium iron phosphate

1. The same battery, in the case of the same remaining capacity, the voltage value changes due to the magnitude of the discharge current.

The higher the discharge current, the lower the voltage is. In the absence of current, the voltage is highest.

2. The effect of ambient temperature on the battery voltage. The lower the temperature, the lower the battery voltage of the same capacity is.

3. The effect of cycling on the battery discharge platform,

As the cycle progresses, the discharge platform of the lithium ion battery tends to deteriorate. The discharge platform is lowered. Therefore, the capacity represented by the same voltage also changes accordingly.

4. Different manufacturers, different capacity lithium-ion batteries, the discharge platform is slightly different.

5. Lithium-ion batteries of different types of electrode materials have large differences in discharge platforms. The discharge platforms of cobalt lithium and manganese lithium are completely different.

All of the above will cause voltage fluctuations and voltage differences, making the battery capacity display unstable.

When the battery capacity is measured by voltage on a mobile phone, it is impossible for the mobile phone to be in a standby state of a small current. Temporary loss of high current, such as turning on the backlight, ringing the ring, especially through, will cause the battery voltage to drop quickly. At this point, the capacity displayed by the phone is reduced more than the actual capacity. When the large current is removed, the voltage of the battery will rise. This will cause the unreasonable phenomenon that the capacity display of the mobile phone will rise instead.

Table of battery voltage versus battery capacity:

Having said that, the following table gives a standard voltage versus battery remaining capacity (left) and a large current constant current discharge is a table of battery voltage versus capacity (right)

100%----4.20V100%----4.20V

90%-----4.06V90%-----3.97V

80%-----3.98V80%-----3.87V

70% ----- 3.92V70% ----- 3.79V ▲

60% ----- ----- 3.87V60% ----- 3.73V

50%-----3.82V50%-----3.68V

40%-----3.79V▲40%-----3.65V

30%-----3.77V30%-----3.62V

20%-----3.74V20%-----3.58V

10%-----3.68V10%-----3.51V

5%------3.45V5%------3.42V

0%------3.00V0%------3.00V