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Analysis of the meaning of the capacity (AH) in the battery

Analysis of the meaning of the capacity (AH) in the batteryRated capacity C, unit safety (AH) of the battery, is the product of discharge current amne (a) and discharge time hours (H). Since AH derived from different discharge parameters in the same battery is different, in order to facilitate the description, measurement, and comparison of battery capacity, a unified condition must be set in advance. In practice, the battery capacity is defined as: discharging the battery to the amount of power given to the set voltage with a set current. It is also possible to say that the battery capacity is: the time to discharge the battery to the set voltage and the product of this current.

In order to set a unified condition, first, according to the difference in battery structure characteristics and use, a number of discharge time rates are set, the most common there is 20 hours, 10 hours time, and the special battery for electric vehicle is 2 hours, write C20 , C10 and C2, where c represents the battery capacity, and the rear followed number indicates the hour number of the type of the battery to be discharged to the set voltage at a certain intensity. Thus, the rated discharge current is obtained using the capacity divided by hours. That is, the capacity is the same as a battery having different discharge time, and their nominal discharge current is very far. For example, a battery capacity of an electric bicycle is 10ah, and the discharge time is 2 hours, and 10AH2 is written. Its rated discharge current is 10 (AH) / 2 (h) = 5a; the battery capacity for a car started is 54ah. , The discharge rate is 20 hours, write 54AH20, its rated discharge current is only 54 (AH) / 20 (h) = 2.7a! For a point of view, if the two batteries are discharged from 5a and 2.7a, they should fall to the set voltage for 2 hours and 20 hours, respectively.

The above-described so-called set voltage refers to the termination voltage (unit V). The termination voltage can be easily understood as: The battery voltage drops to the minimum value of the damage when discharge. The termination voltage value is not fixed, it decreases as the discharge current increases, the larger the same battery discharge current, the lower the termination voltage, and the higher it should be. That is, the large current discharge allows the battery voltage to drop to a lower value, and the small current discharge is not, otherwise it will cause damage.

The current intensity of the battery is often expressed by the magnification, writing NCH. N is a multiple, and C represents the number of times of capacity, h indicates the number of hours specified by the discharge time. The value of H here is only a prompt related battery that is a discharge time rate, so when the battery is specifically described, the magnification is often written as an NC in the form of an NC without writing the mark. The multiple N multiplied by capacity C is equal to current A. For example, a 20AH battery is discharged from 0.5c magnification, 0.5 ¡Á 20 = 10A. For an angle example: a car starts the battery capacity of 54ah, and the output current is 5.4a, then it is 5.4 / 54 = 0.1c at this time. The figure below is the relationship between a 20-hour battery product at the termination voltage and discharge time at different discharge rates, which are representative of the usual lead-acid battery.

Battery discharge curve

The number of AH (current and time product) obtained by the same battery under different discharge currents is different. It is assumed that the battery has a capacity of 10ah, which is only 1 hour at 0.6C magnification, which is only 1 hour, and the amount of power that can be released is only 6A ¡Á 1H = 6ah. The discharge time of 0.5a is 0.5a is 0.5a, and the discharge amount is 0.5a ¡Á 20h = 10ah. Although the termination voltage of the former is much lower than the latter, the amount of power that can be released is much smaller than the latt  Recommend: LiFePO4 Battery Manufacturer Energy storage battery Manufacturer Integrated machine energy storage battery series Manufacturer Lead lithium battery Manufacturer Outdoor Backup Battery Manufacturer Portable outdoor power supply Manufacturer Power battery Manufacturer Powerwall LiFePO4 Battery Manufacturer Battery rack Manufacturers Telecom LiFePO4 Battery Manufacturer Wall mounted battery storage Manufacturer China Lifepo4 Battery