With the development of lithium battery, the direction of large-capacity lithium battery is the main concern factor in the battery consumption market. Many lithium battery manufacturers to meet consumer demand, coupled with fierce competition in the industry, now the capacity of large capacity lithium battery is serious false standard, a lot of battery manufacturers of lithium battery actual capacity and advertised capacity gap, there are big and small, and the price level.
So how to detect the capacity of large-capacity lithium batteries has a virtual standard? If I have a dummy capacity, what's the dummy capacity?
1. Measuring tool of large-capacity lithium battery: measuring ruler
To quickly estimate the capacity of a lithium battery, the usual formula (for estimation only) is to calculate the cell volume, not the battery case.
Battery capacity = thickness * width * length *K (K unit is mah/mm3)
The range of K value is (0.07~0.11), and the K value depends on the size of the capacity. The larger the capacity is, the larger the K value is, and the smaller the capacity is, the smaller the K value is.
In the actual calculation, the value of K can be set to 0.1 by default. For example, the calculation capacity of 103450LP (10mm thick, 34mm wide, and 50mm long) is 10*34*50*0.1=1700, and the actual capacity is more than 1800mah; For example, 603048LP (6mm thick, 30mm wide, 48mm long), calculation capacity =6*30*48*0.1=864, the actual capacity can be achieved 900mah.
2. Prepare a galvanometer
Lithium battery capacity = voltage × discharge current × discharge time
I'm sure many of you who have studied physics know how to do it.
3. An electrical device, such as a lamp, that is rated to discharge electricity
Directly connected to the discharge, until the light dim out, record the time t, the large capacity lithium battery can be estimated C:
C = UIt
The corresponding relationship between lithium battery open-circuit voltage and battery capacity is generally as follows. The percentage is the remaining capacity of the battery. On the right side is the open-circuit voltage (OCV) of the corresponding battery.
100% - 4.20 V
90% - 4.06 V
80% - 3.98 V
70% - 3.92 V
60% - 3.87 V
50% - 3.82 V
40% - 3.79 V
30% - 3.77 V
20% - 3.74 V
10% - 3.68 V
5% - 3.45 V
0% - 3.00 V
This is the Impress cell production for many years to do a share of experience, from the data, you can also use the universal voltmeter to do a large capacity lithium battery, is to see the remaining capacity of the large lithium battery, and then to measure the voltage, and do the corresponding, you can probably make a judgment.