Briefly describe the important performance indicators of lithium batteries

Important performance indicators of lithium batteries The capacity of the 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 battery The internal resistance of the battery refers to the resistance experienced by the current flowing 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. Voltage open circuit voltage 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 4.14.2V, 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 operating 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. Discharge platform time The discharge platform 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. Charge-discharge rate 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 The self-discharge rate, also known as the charge retention capability, refers to the retention capability of the battery's stored power under certain conditions when the battery is in an open circuit state. It is critically affected by factors such as battery manufacturing technology, materials, and storage conditions. It is an important parameter for weighing battery performance. Efficiency Charging efficiency refers to a measure of the degree to which the electrical energy consumed by the battery during the charging process 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 certain discharge conditions and the rated capacity of the battery. It is mainly affected by factors such as discharge rate, ambient temperature, internal resistance, etc. Generally, the higher the discharge rate, The lower the discharge efficiency. The lower the temperature, the lower the discharge efficiency. Cycle life The cycle life of a battery refers to the number of charge and discharge times the battery has undergone under a certain charging and discharging system when the battery capacity drops to a certain value. Lithium battery GB stipulates that the capacity retention rate of the battery after 500 cycles under 1C conditions is above 60%. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Is the ternary lithium battery good?