What are the important performance indicators of lithium batteries

The capacity of the lithium battery The capacity of the battery is divided into the rated capacity and the actual capacity. The rated capacity of the battery refers to the amount of power that the battery should supply when it is discharged to the final voltage at a rate of 5 hours under the condition of an ambient temperature of 20 ℃ ± 5 ℃, and is represented by C5. The actual capacity of the battery refers to the actual amount of electricity released by the battery under certain discharge conditions, which is closely affected by the discharge rate and temperature (so strictly speaking, the battery capacity should specify the charge and discharge conditions). Capacity unit: mAh, Ah (1Ahu003d1000mAh). The internal resistance of the lithium battery battery internal resistance refers to the resistance that the current flows through the battery when the battery is working. It is composed of ohmic internal resistance and polarization internal resistance. The large internal resistance of the battery will reduce the battery discharge working voltage and shorten the discharge time. The internal resistance is closely affected by the battery material, manufacturing process, battery structure and other factors. The internal resistance of the battery is an important parameter for weighing the performance of the battery. The voltage open circuit voltage of a lithium battery refers to the potential difference between the positive and negative electrodes of the battery when the battery is in a non-working state, that is, when there is no current flowing in the circuit. Under normal circumstances, the open circuit voltage of the lithium battery after overflow is about 4.1-4.2V, and the open circuit voltage after discharge is about 3.0V. By testing the open circuit voltage of the battery, the state of charge of the battery can be judged. Working voltage, also known as terminal voltage, refers to the potential difference between the positive and negative poles of the battery when the battery is working, that is, when there is current flowing in the circuit. In the battery discharge state, when the current flows through the battery, there is no need to overcome the resistance caused by the battery's internal resistance, so the working voltage is always lower than the open circuit voltage, and the opposite is true when charging. The discharge working voltage of the lithium battery is around 3.6V. The discharge plateau time of the lithium battery The discharge plateau time refers to the discharge time to a certain voltage when the battery is fully charged. For example, measure the 3.6V discharge platform time of a ternary battery, charge it at a constant voltage to a voltage of 4.2V, and stop charging when the charging current is less than 0.02C, that is, after it overflows, then leave it aside for 10 minutes at any rate of discharge current The discharge time when the discharge reaches 3.6V is the discharge plateau time at this current. Because the working voltage of some electrical appliances that use lithium batteries has voltage requirements, if it is lower than the required value, it will not work. Therefore, the discharge platform is one of the most important criteria for weighing the battery performance. The charge-discharge rate of lithium battery The charge-discharge rate refers to the current value required when the battery discharges its rated capacity within a specified time. 1C is numerically equal to the rated capacity of the battery and is usually represented by the letter C. If the nominal rated capacity of the battery is 10Ah, then 10A is 1C (1 rate), 5A is 0.5C, 100A is 10C, and so on. Self-discharge rate of lithium battery The self-discharge rate, also known as the charge retention capacity, refers to the retention capacity of the stored power of the battery under certain conditions when the battery is in an open circuit state. It is critically affected by factors such as the manufacturing process, materials and storage conditions of the battery. It is an important parameter for weighing battery performance. The charging and discharging efficiency of a lithium battery. The charging efficiency refers to a measure of the degree to which the electric energy consumed by the battery is converted into the chemical energy that the battery can store. It is critically affected by battery technology, formula and battery working environment temperature. Generally, the higher the ambient temperature, the lower the charging efficiency. Discharge efficiency refers to the ratio of the actual power discharged to the terminal voltage under a certain discharge condition to the rated capacity of the battery. It is mainly affected by factors such as the discharge rate, ambient temperature, and internal resistance. In general, the higher the discharge rate, The lower the discharge efficiency. The lower the temperature, the lower the discharge efficiency. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How should new energy vehicles maintain their batteries in winter?