In addition to the battery capacity, do you know what the Wh on the battery means?

　　In our daily contact with battery products, such as nickel-metal hydride batteries, lead-acid batteries, lithium batteries and other products, we will mark parameters such as Ah and Wh.

　　The capacity of the battery refers to the electric energy that the battery can store, in Ah as the unit. It has nothing to do with the voltage of the battery. For example, a lead-acid battery is only related to the area of the plate. The larger the plate area, the larger the capacity. The voltage of the battery is related to the battery's series unit. Each unit has a voltage of 2V, and the more series units there are, the higher the voltage. There is no such thing as power in the technical indicators of lead-acid batteries.

　　Most mobile devices and cameras use lithium battery packs, and most consumers do not understand the capacity labels on these battery labels, such as mAh and Wh. In fact, learning to understand these signs is very simple and very practical.

　　Take the common mobile phone lithium-ion battery as an example. In fact, if the two batteries are also mobile phone batteries, their capacity can still be compared with mAh. But if they are not the same type of products, the direct comparison may be wrong. Are they not all lithium batteries? Isn't it all the same? Why can't it be compared? Although the same is a lithium battery, the voltage of the two batteries is actually different, that is, because of the voltage, it is not comparable to the size of the mAh number.

　　In layman's terms, the physical meaning of battery capacity refers to how much charge the battery can hold or release. We often use Ah (Ampere hour) or mAh (Milliamp hour) to express.

　　According to the definition formula of current: I=Q/t, we know that Q=It, the unit of current I is mA (milliampere), t represents time, the unit is hour (hour), so our battery capacity unit is mAh.

　　That is to say, if the capacity of a battery represents 1000mAh, if the current when it is working is 100mA, it can theoretically supply power for 10 hours.

　　However, we can see from the formula that Q=It, and no voltage is involved, so this unit can only indicate how many coulombs of charge can be accommodated inside the battery. But it cannot tell how much work this battery can do, and what the maximum power the battery can provide.

　　The working voltage of different types of products is different. Therefore, we often see a number in Wh next to mAh. The work that the battery can do W=UIt=UQ, and the unit of voltage U*current I is W (watts), so W in the battery is represented by Wh, which indicates how much work the battery can do.

　　Wh is a quantity proportional to voltage, current, and time. MAh is usually used as an indicator of battery charging and discharging. It is an indicator proportional to the charging (discharging) current and time of the battery. To make it comparable or convertible with Wh, the voltage of the battery must be known. Simply put Wh=mAh/1000*voltage.

　　For example, the voltage of a 6600mAh battery is 14.4V, 14.4V*6600mAh=95.04Wh, then all the work it can release is 6.6*14.4*3600=342144 Joules.

　　Lithium-ion battery (LIB) has become the main energy storage solution in modern social life. Among them, lithium iron phosphate batteries are a perfect substitute for lead-acid batteries, and are the first choice for grid-connected peak shaving, off-grid energy storage, photovoltaic energy storage, UPS, data center and other industries.