Discharge rate F: [1/hour], meaning "N hours charge (discharge) rate, often just say "number", not to say the unit; F is also called "N hours charge (discharge) rate", F =1/(N hours), generally can be calculated as follows: I = 0.1 X [1/(N hours)] X C
For example, the battery capacity of 2200mAh, charged with a current of 0.1C, equivalent to the clear: the battery charging current I = 0.1 [1/hour] X 2200 [mAh] = 220 [mA]
With the help of the above diagram of understanding the capacity and discharge platform of lithium batteries, can better understand the reasoning behind the capacity of the rechargeable battery and the discharge platform of the battery, which can also be said to measure the working time of the battery high power, the same two battery capacity is the same, fully charged, assuming that at the same time from 4.2V to 3.7V, but a long time, a short time, that is, a long time battery platform high, that is, high voltage The time working time is long, such as these two batteries used in cell phones, standby time is the same, but the two phones together to call, the platform time long battery notice time will be long, the platform time short battery talk time will be short Two, for this figure, another meaning, it is also very meaningful to understand the power management monitoring of lithium batteries.
For example, at present, there are two general methods for monitoring the power of rechargeable batteries.
Measuring the battery voltage method. When the charger detects the battery voltage while charging, it is considered full when the voltage reaches the specified voltage value. Such as lithium batteries are considered full when the voltage is charged to 4.2V. Detect the voltage of the voltmeter accuracy to achieve plus or minus 1% accuracy. Because the lithium battery overcharge to damage. If you want to monitor the battery charging and discharging, there are very mature circuits on the book can be referred to, if only to measure it, then it is good to do, according to the capacity of the calculation of the load resistance, with a standard discharge current discharge, then test the voltage, as long as it can reach or close to the nominal discharge time on the line.
Measuring battery voltage this method, there are many shortcomings. For example, for batteries made by different manufacturers, the relationship between the open circuit voltage and capacity varies, etc. The advantage is that the design cost is relatively low.
There is also a common method to monitor the remaining capacity is, in some places where more accurate battery capacity is required, to know the remaining battery capacity with estimating the battery usage time, by measuring the net charge flowing into/out of the battery to estimate the remaining battery capacity. The total current flowing into/out of the battery is integrated, that is, the area under the curve in the graph is found, and the number of net charges obtained is the remaining capacity.
This method of calculating battery capacity is currently considered to be a more accurate method of calculating battery power. Of course the design cost is also relatively high.
