How to distinguish the relationship between battery voltage and capacity?

One useful feature of lithium-ion batteries is that, when they are discharged, the voltage of the battery decreases with the passage of the charge and has a fairly steep slope. This gives us another approximate metering method. The method of taking the battery voltage. It's like measuring the height of the water in a tank gives you an idea of how much water is left. But actually the voltage of the lithium battery is much more complicated than measuring the height of the calm water in the tank. The voltage used to estimate the residual capacity of a battery has the following instability: for the same battery, the voltage value varies with the discharge current under the same residual capacity. The higher the discharge current, the lower the voltage. In the absence of current, the highest voltage; The effect of ambient temperature on battery voltage, the lower the temperature, the lower the battery voltage of the same capacity; The influence of the cycle on the discharge platform of the battery, with the progress of the cycle, the discharge platform of the lithium ion battery tends to deteriorate. Discharge platform lowered. So the capacity of the same voltage changes accordingly; Different manufacturers, different capacity of lithium ion batteries, the discharge platform slightly different.

Different types of electrode materials for lithium ion batteries, discharge platform has great differences. Cobalt lithium battery and manganese lithium battery discharge platform is completely different. All of the above will cause voltage fluctuations and voltage differences, making the battery capacity display become unstable. When the battery capacity is measured by voltage on a mobile phone, it is impossible for the mobile phone to be in standby state with low current all the time. Temporary losses of large current, such as turning on the backlight, playing a ringtone, and especially passing through, can quickly reduce the battery voltage. At this time, the capacity displayed by the mobile phone has to be reduced more than the actual capacity. When the high current is removed, the battery voltage goes back up. This will cause the unreasonable phenomenon that the display of mobile phone capacity increases instead.

For example, the battery capacity of 3.6v, 19ah, 19ah is not put into 0v, but 2. Or 3. When, the discharge capacity is 19ah, if put into 0v, the capacity will be a little more than 19, if put too much, it will damage the battery life.

Design, excellent instrument of basically the same cut-off voltage and battery voltage, when the voltage reaches a value, such as 3 v battery is put out, or close to put out, instrument are at the lowest operating voltage, if the instrument of the minimum operating voltage is higher, such as less than 3.6 v will not be able to work, there is a battery and electric, instrument can't work, this kind of circumstance, should improve the external power supply voltage

The electric current is very small and very slow.

One useful feature of lithium-ion batteries is that, when they are discharged, the voltage of the battery decreases with the passage of the charge and has a fairly steep slope. This gives us another approximate metering method. The method of taking the battery voltage. It's like measuring the height of the water in a tank gives you an idea of how much water is left. But actually the voltage of the lithium battery is much more complicated than measuring the height of the calm water in the tank. The voltage used to estimate the residual capacity of a battery has the following instability: for the same battery, the voltage value varies with the discharge current under the same residual capacity. The higher the discharge current, the lower the voltage. In the absence of current, the highest voltage; The effect of ambient temperature on battery voltage, the lower the temperature, the lower the battery voltage of the same capacity; The influence of the cycle on the discharge platform of the battery, with the progress of the cycle, the discharge platform of the lithium ion battery tends to deteriorate. Discharge platform lowered. So the capacity of the same voltage changes accordingly; Different manufacturers, different capacity of lithium ion batteries, the discharge platform slightly different.

Different types of electrode materials for lithium ion batteries, discharge platform has great differences. Cobalt lithium battery and manganese lithium battery discharge platform is completely different. All of the above will cause voltage fluctuations and voltage differences, making the battery capacity display become unstable. When the battery capacity is measured by voltage on a mobile phone, it is impossible for the mobile phone to be in standby state with low current all the time. Temporary losses of large current, such as turning on the backlight, playing a ringtone, and especially passing through, can quickly reduce the battery voltage. At this time, the capacity displayed by the mobile phone has to be reduced more than the actual capacity. When the high current is removed, the battery voltage goes back up. This will cause the unreasonable phenomenon that the display of mobile phone capacity increases instead.

Battery capacity is one of the important performance indicators to measure battery performance. It represents the amount of electricity released by the battery under certain conditions (discharge rate, temperature, termination voltage, etc.) (js-150d can be used for discharge test), that is, the capacity of the battery, usually in amperes · hours (referred to as A·H, 1A· H =3600C).

Battery capacity can be divided into actual capacity, theoretical capacity and rated capacity according to different conditions. The calculation formula of battery capacity C is C= integral of t0It1dt (the integral of current I in the time from t0 to t1), and the battery is divided into positive and negative poles.

Battery capacity can be divided into actual capacity, theoretical capacity and rated capacity according to different conditions.

Under a certain discharge rate from 25 ℃ to discharge voltage of the minimum capacity is a design and production rule of battery capacity, this is called a rated capacity of the discharge rate of RH.

Square lithium ion battery

Square lithium ion battery

The battery capacity is generally calculated in AH(ampere hour), and the other is in the CELL(unit plate) watts (W). (W/CELL)

1.Ah(ampere hour) calculation, discharge current (constant current) I discharge time (hour)T. For example, if the continuous discharge current of 7AH battery is 0.35a, the time can be 20 hours continuously.

2. The charging time is 15 hours. The charging current is 1/10 of the battery capacity.

Battery capacity refers to the size of the battery storage capacity. The unit of battery capacity is "mAh", and the Chinese name is mAh (" Ah "is generally used for convenience when measuring large-capacity batteries such as lead batteries, and the Chinese name is" anshi ", 1Ah=1000mAh). If the rated capacity of the battery is 1300mAh, that is, the current of 130mA discharges the battery, then the battery can last for 10 hours (1300mAh/130mA=10h). If the discharge current is 1300mA, the power supply time is only about one hour (actual operating time varies depending on the actual capacity of the battery). This is the ideal situation analysis, digital device when the actual work current could not remain constant in a numerical (digital cameras, for example, working current, flash and other parts of the LCD display larger changes in the open or closed), so the battery to the power supply time only on a device is a about value, and this value is only estimated by actual operating experience.

Usually we talk about battery capacity in ampere-hours, which is based on a battery that has been identified.

Let's say the battery capacity of this cell phone; The battery capacity of this battery car is different for different batteries. For the battery voltage has been determined, without considering the actual voltage, just say ampere hour can represent the battery capacity.

However, for batteries with different voltages, we cannot simply use ampere hours to represent capacity. For example, a 12V20AH battery and a 15V20AH battery, even if they are both 20AH, can supply the same power load and the equipment can work normally, but the duration is different, so the standard capacity should be based on work.

For example, a device can support the 12 v and 24 v can also support, with a 12 v (20 ah) batteries, can provide an hour, then use two pieces of series will be 24 v (20 ah) including Ann did not increase, but the duration of a times, so cells hold capacity should be considered at this time for the work, not only consider to Ann.

W (work) =P (power) *T (time) =I (current) *U (voltage) *T (time)

This discussion of battery capacity is of practical significance, must be practical and realistic, otherwise it may appear that a mobile phone battery is larger than the battery capacity of the battery car, which is obviously not scientific.

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