Explanation of common terms about lithium battery

Lithium battery-capacity, voltage, internal resistance, multiplier/hour rate, self-discharge, memory effect, cycle life capability • The capacity of a lithium battery is given by a certain discharge condition, called the capacity of the lithium battery, with the symbol C (capacity ) Means. Commonly used units are ampere-hours (Ah) or milliamp-hours. Voltage•Open circuit voltage (OCV) The terminal voltage of a lithium battery in an open circuit state is called the open circuit voltage. The open circuit voltage of a lithium battery is equal to the difference between the positive electrode potential and the negative electrode potential. •Working voltage Working voltage refers to the voltage displayed during the discharge process of the lithium battery after the load is connected, also known as the discharge voltage. The operating voltage of a lithium battery when it is initially discharged is called the initial voltage. Due to the existence of ohmic resistance and polarization overpotential, the operating voltage of the lithium battery is lower than the open circuit voltage after the load is connected. Internal resistance•The resistance that appears when current flows through the lithium battery reduces the voltage of the lithium battery. This resistance is called the internal resistance of a lithium battery. • The internal resistance of a lithium battery is not constant and will change with time during the discharge process, because the composition of the active material, the concentration of the electrolyte, and the temperature are constantly changing. • The internal resistance of lithium batteries includes ohmic internal resistance and polarization internal resistance, and polarization internal resistance includes electrochemical polarization and concentration polarization. The existence of internal resistance makes the terminal voltage of the lithium battery lower than the electromotive force and open circuit voltage of the lithium battery when discharging, and the terminal voltage when charging is higher than the electromotive force and open circuit voltage. •Ohm resistance follows Ohm's law; polarization resistance increases with the increase of current density, but it is not linear, and always increases linearly with the increase of logarithm of current density. Charge and discharge rate multiplier: refers to the current value required for the lithium battery to release the rated capacity within the specified time. If the rated capacity of the lithium battery is 600mAh, then 600mA is 1C (1 multiplier), 300mA is 0.5c, 6A (6000mA) is 10C, and so on. Hour rate: Also known as hour rate, it refers to the number of hours required for a lithium battery to discharge its rated capacity with a certain amount of power. If the rated capacity of the lithium battery is 600mAh, it takes 1 hour to discharge the 600mA current, so the 600mA current is the rate of 1 hour. Self-discharge Self-discharge refers to the spontaneous reaction of the lithium battery when it is not connected to the outside world. Chemical energy loss. The self-discharge rate of a lithium battery is the ratio of the initial capacity of the lithium battery minus the storage capacity of the lithium battery to the initial capacity after the lithium battery has been stored for a period of time. The self-discharge rate of lithium-ion lithium batteries does not exceed 10% per month, which is far lower than 30% of nickel-hydrogen lithium batteries and 15% of nickel-cadmium lithium batteries. Memory effect The memory effect of a lithium battery means that the lithium battery does not discharge during charging, and the undischarged electricity makes the plates crystallize, which is called the memory effect. When there is a memory effect, the capacity of the lithium battery will drop significantly. Before the lithium battery is charged and discharged, the nickel-cadmium lithium battery has no memory problem. Cycle life•The cycle life of a lithium battery is the cycle life of a lithium battery fully discharged after being fully charged. This cycle continues until the capacity decays to 75% of the original capacity. • The cycle life is related to the charging and discharging conditions of the lithium battery. • The 1C charge-discharge cycle life can reach 1000-1500 times at room temperature. 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: What are the hidden dangers of using lithium batteries?