To measure the performance of cylindrical (electronic cigarette) batteries, there are several important indicators:
　　 First, charge and discharge rate: the higher the better
　　 "C" is a special symbol that describes the magnitude of the battery charge and discharge current. The 1C discharge represents the amount of current that can be placed from full charge to empty within 1 hour. The iPhone 6 battery capacity is 1810mAH, then the 1C discharge current of this battery is 1.81 amps; the battery capacity of each battery used in the BYD e6 electric car is 200AH, then the battery 1C discharge current is 200 amps. If a battery is discharged at a high rate, it usually emits less energy than a low rate.
　　 Second, the number of charge and discharge cycles: the more the better
　　 500 times is a common value of lithium batteries, and the number of charge and discharge of lithium batteries made according to different materials ranges from 300 to 3000 times. The specific meaning of this value may be slightly different for each factory, which can be roughly understood as: according to the manufacturer's specified charge and discharge rate (such as 1C discharge, 0.3C charge; each time from 0% charge to 100%, according to this cycle) After 500 cycles, the battery capacity remains at the first 80%. The relationship between the number of charge and discharge cycles and the habit of use is too great, let us give a few examples.
　　 1. Effect of charge and discharge intensity on the number of cycles
　　 Factory labeling: every time from 0% charge to 100%, 1C release, 0.3C charge, 500 times after the capacity decay to 80%, this is the most demanding test cycle, it can not be so strict, see below
　　 If the cycle of electricity is 25%-75%, 1C put, 0.3C charge, after 2000 times the capacity decays to 80%
　　 If the cycle of electricity is 50%-100%, 1C, 0.3, and 1800, the capacity is attenuated to 80%
　　 2, the impact of shallow filling on the life of the
　　 Factory labeling: every time from 0% charge to 100%, 1C release, 0.3C charge, 500 times after the capacity decay to 80%, is the most stringent test cycle, can not be so strict, see below
　　 Each cycle of electricity is in the range of 25%-75%, 1C put, 0.3C charge, after 2000 times the capacity decays to 80%
　　 Each cycle of electricity is 50%-100%, 1C put, 0.3 charge, 1800 times, the capacity decays to 80%
　　 The above two examples show that the smaller the charge and discharge rate, the more favorable the life is improved; the shallow charge and shallow release is also beneficial to the life improvement.
　　 Third, the internal resistance: the smaller the better
　　 This parameter changes with the load and weight, temperature and other factors. As the battery life decreases, the internal resistance also increases. The smaller the internal resistance, the higher the charge and discharge of the battery. The internal resistance of the 18650 ordinary battery is about 50mΩ, and the power type 18650 battery is about 15mΩ. I want to know how much internal resistance needs to be measured with a dedicated device. A normal multimeter does not work.
　　 Fourth, battery consistency
　　 The higher the consistency of the cylindrical (electronic cigarette) cells produced by the same material and the same process on the capacity, internal resistance, charge and discharge curves, the better. It is critical that a cylindrical (e-cigarette) cell can form a battery pack on a large scale. The larger the battery pack size, the higher the consistency requirement.