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What data are used to measure the performance of lithium-ion batteries?

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Charge discharge ratio: the higher the better. C is a special symbol describing the charge and discharge current of the battery. 1C discharge indicates the current of the battery from full to empty within 1 hour. If the capacity of iPhone 6 battery is 1810mah, the 1C discharge current of the battery is 1.81 amps; If the capacity of each battery used by BYD E6 electric vehicle is 200ah, the discharge current of battery 1C is 200 amps. If a battery discharges at a high rate, it usually releases less energy than a low rate discharge.

Number of charging and discharging cycles: the more the better. 500 times is the common value of lithium-ion batteries. The charge and discharge times of lithium-ion batteries manufactured according to different materials range from 300 to 3000. The detailed meaning of this value may be slightly different for each plant, which can be roughly understood as: according to the charge discharge rate specified by the manufacturer (such as 1C discharge, 0.3C charge; from 0% to 100% each time, follow this cycle), after 500 cycles, the initial 80% battery capacity remains unchanged. There are too many relationships between the times of charging and discharging and usage habits. Let's give a few examples. 1. Effect of charge discharge intensity on cycle times: Factory Description: each time from 0% charge to 100%, 1c discharge, 0.3C charge, the capacity decreases to 80% after 500 times. This is the most serious detection cycle, and it can also be less strict. As shown in the figure below, if the power of each cycle is 25% - 75%, 1c discharge and 0.3C charge, the capacity will decrease to 80% after 2000 times; if the power of each cycle is 50% - 100%, 1c discharge and 0.3 charge, the capacity will decrease to 80% after 1800 times. 2. Impact of shallow charging and discharging on service life. Factory tips: from 0% charge to 100%, 1c discharge, after 500 times of 0.3C charge, the capacity decays to 80%, which is the most serious detection cycle. It can also be less strict. It can be seen from the following that the power cycle is 25% - 75%, 1c discharge, 0.3C charging, and the capacity attenuates to 80% after 2000 times. Each power cycle is 50% - 100%, 1c discharge, 0.3 charging, and the capacity attenuates to more than 80% after 1800 times. It can be seen from the two examples that the smaller the charge discharge ratio, the more conducive to improve the service life; Shallow charge and discharge is also beneficial to improve the service life.

Internal resistance: the smaller the better. This parameter changes at any time with load weight, temperature and other factors. With the shortening of battery life, the internal resistance increases gradually. The smaller the internal resistance, the higher the charge discharge rate. The internal resistance of 18650 ordinary battery is about 50m, and the internal resistance of 18650 power battery is about 15m. If you want to know how big the internal resistance is, you need to use special equipment to measure it. Generally speaking, a multimeter cannot.

Battery consistency the higher the consistency of battery capacity, internal resistance and charge discharge curve of the same material and process, the better. The larger the size of the battery pack, the higher the consistency of the.

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