The difference between power type and capacity type in lithium battery

Combinations: ICR18500-3 s2p nominal voltage: 11.1 V discharge voltage: 11.1 V to 12.6 V regular discharge current is: 0-2 a large capacity for 3-4 a nominal capacity: to MahA, there are a variety of standard lasts discharge current: 0.2 C maximum continuous discharge current: 1 C working temperature: charging: 0 ~ 45 ℃ discharge: - 20 ~ 60 ℃ product size: MAX39 finished resistance: * 56.6 * 99 mm, 280 m or less Ω standard weight: protection board: IC - S8254AAJ + MOS - AO4409 lead models: JST - positive plug UL1007 VHR - 2 p / 24 # line, the line is 100 mm long protect parameters: the overcharge protection/each string of 4.35 + / - 0.025 V voltage discharge voltage protection over-current value: 2.4 + / - 0.08 V 10 ~ 25 a12v lithium battery specification parameters: voltage: 12 V battery capacity: there is no standard capacity, capacity is according to use electrical appliances, or equipment to determine the specific requirements, the general capacity of: 2200 ma/h, 5 ah, 10 ah, some electric capacity up to 20 ah, or 50 ah. Batteries in parallel, the more the greater the capacity. According to the physical formula: in parallel circuit: I total =I1+I2+I3 volume: the volume of 12V lithium battery, to be determined according to the capacity of the battery, there is no uniform specifications. The larger the battery capacity, the larger the volume weight: now a lot of equipment needs a larger capacity, lighter weight of the lithium battery, such as electric vehicles, used to be lead-acid battery, now many electric vehicles become lithium battery, because the lithium battery capacity, light weight, small size. Charge and discharge current: the charge and discharge current of lithium battery is determined according to the power of the device, and the electric power formula: P=UI. On the basis of constant voltage, the greater the power of the device, the greater the current to be output. 12V lithium battery USES: electric vehicles, power tools, notebook, mobile DVD, UPS, GPS, medical equipment and so on

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.

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.

To a battery for constant current constant voltage charging, and then constant current discharge, how much electricity is released is the capacity of the battery, battery, nickel metal hydride battery, etc., but lithium battery is not, it has a minimum discharge voltage, that is, the discharge voltage can not be lower than 2.75V, usually with 3.0V as the lower limit protection voltage. For example, if the capacity of lithium battery is 1000mAh, then the charge and discharge current is 1000mA. The highest voltage of the battery is 4.2v and put it into 3.0v, and the released capacity is the most real capacity of the battery.

Battery capacity is an important indicator to measure the performance of the battery. Ann is commonly used in the comings. Discharge time (hours) and the floorboard of the discharge current (amps), namely capacity = x discharge current discharge time. The actual capacity of the battery, how much depends on the active substances in the cells and the utilization of active material. The more amount of active material is, the higher the utilization of active material, the capacity of the battery. Vice volume is smaller, there are many factors which can influence the battery capacity, common has the following kinds:

(1) influence of discharge rate on battery capacity

The capacity of lead battery decreases with the increase of discharge rate, that is, the larger the discharge current is, the smaller the capacity of the battery will be calculated. Therefore, for a given battery, if it is discharged at different rates, it will have different capacity.when we talk about capacity.we must know the rate or times of discharge.

(2) influence of temperature on battery capacity

Temperature has a great influence on the capacity of lead-acid battery. Generally, as the temperature decreases, the capacity decreases. The relationship between capacity and temperature is as follows:

Ct1 + k = Ct2/1 (t1, t2) t1t2 were the temperature of the electrolyte, k for the temperature coefficient of capacity, Ct1 temperature for t1 capacity (Ah), Ct2 is when the temperature of t2 capacity (Ah) in battery production standards, typically a rated temperature for normal temperature, such as t1 as the actual temperature, t2 as the standard temperature, (general is 25 degrees Celsius) negative plate is affected by low temperature sensitive than positive plate. When the temperature falls, electrolyte electrolyte viscosity increases, ion by larger resistance, diffusion ability to drop, electrolyte resistance also increases, the electrochemical reaction resistance With the increase of force, part of lead sulfate could not be converted normally.

(3) influence of termination voltage on battery capacity

When the battery discharge to a certain voltage, voltage drop sharply, actually gained by the energy is very small, if long-term deep discharge, the damage to the battery is quite large. So must terminate discharge at a voltage, the globe discharge voltage discharging termination voltage. Set the discharging termination voltage, is of great significance to prolong the service life of the battery. Generally we repair of electric vehicle batteries, electric motorcycle battery discharging termination voltage of 1.75 volts per cell, which means a 12-volt batteries is 6, the discharging termination voltage is 6 x 1.75 = 10.5 v. [2]

(4) influence of plate geometry on battery capacity

When the amount of active material is constant, the geometrical area of the plate in direct contact with the electrolyte increases and the battery capacity increases. Therefore, the geometrical size of the plate has a significant impact on the battery capacity.

Plate thickness on the capacity of the impact

With a certain amount of active material, the battery capacity decreases with the increase of plate thickness. The thicker the plate is, the smaller the contact surface between sulfuric acid and active material will be. The lower the utilization rate of active material is, the smaller the battery capacity will be.

The effect of plate height on capacity

In the battery, the utilization rate of the active material of the upper and lower parts of the electrode plate is significantly different. The experiment confirmed that the current density of the upper part of the electrode plate is about 2 times ~~2.5 times higher than that of the lower part in the initial stage of discharge. This difference decreases gradually with the passage of discharge, but the current density of the upper part is larger than that of the lower part.

(3) plate area on the capacity of the impact

The quantity of active substance must, plate geometry size, the greater the utilization of active material is higher, the greater the capacity of the battery. The battery shell is the same, under the condition of constant quality of active matter, using thin plate increase plate number, also is to increase the area of effective reaction plate, thus improving the utilization of active material, increase the capacity of the battery.

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