Summarize common terms for lithium-ion batteries

General terminology of lithium-ion batteries In the lithium-ion battery industry, we often meet and communicate with friends to express some terms, such as battery capacity, discharge rate, voltage, internal resistance, cycle life, remaining capacity SOC, etc. Answer: The battery capacity refers to the amount of power that a lithium-ion battery can obtain under certain discharge conditions. We understand in high school physics that the formula of electricity is Qu003dI*t, the unit is coulomb, and the capacity of a battery is meant to be Ah or mAh. This means that a 1AH battery can be discharged for 1 hour with a full current of 1A. The battery of an Apple mobile phone is generally about 2000mAh, the lithium-ion battery of an electric bicycle is generally about 8-15ah, and the battery of an electric car is generally 20~200Ah. For example, BYD's electric car e6 is a 200Ah battery. b. Charge rate/discharge rate refers to the amount of charge and discharge current, which is generally calculated as a multiple of the nominal capacity of the battery, generally referred to as a few C for short. Regarding a battery with a capacity of 1500mAh, 1Cu003d1500mAh is specified. If the battery is discharged at 2C, it will be discharged at 3000mA. The battery is discharged at 0.1°C and charged and discharged at a current of 150mA. C. Open circuit voltage The battery voltage generally refers to the rated voltage of a lithium-ion battery (also called the rated voltage). The nominal voltage of an ordinary lithium-ion battery is generally 3.7V, and we also call its voltage platform 3.7V. When we say voltage, we usually mean the open circuit voltage of the battery. When the battery capacity is 20~80%, the voltage is concentrated around 3.7v (3.6~3.9v), and the capacity is too high or too low, and the voltage changes greatly. d. Energy/Electricity When the battery is discharged at a certain standard, the energy (E) released by the battery is Wh (watt hour) or KWh (KWh), 1KWhu003d1KWh. There is a basic concept in the physics book, E is equal to U multiplied by I multiplied by t, and also equal to battery voltage multiplied by battery capacity. The power formula is Pu003dU*Iu003dE/t, which represents the energy released per unit time. The unit is W (watt) or KW (kilowatt). Regarding a battery with a capacity of 1500mAh, the nominal voltage is generally 3.7v, and the corresponding energy is 5.55wh. Because the internal resistance of the large intestine cannot be equated with an ideal power source, there is a certain internal resistance. Internal resistance is energy consumption, of course, the less the better. The internal resistance of the battery is in milliohms (m). The internal resistance of a battery is generally composed of ohmic internal resistance and polarization internal resistance. The size of the internal resistance is affected by the battery material, manufacturing process and battery structure. f. Cycle life One charge and discharge of a battery is called a cycle, and cycle life is an important indicator of battery life performance. According to the IEC standard, the discharge voltage of lithium-ion batteries is 0.2~3.0v, and the charging voltage is 1C~4.2v. After 500 cycles, the battery capacity remains at least 60% of the initial capacity. This means that the cycle life of lithium-ion batteries is 500 times that of ordinary batteries. According to national standards, mobile phone batteries should maintain 70% of their original capacity after 300 cycles. (Source: iYPOWE) The battery capacity of a mobile phone is less than 60% of the original capacity and is generally considered to be scrapped. g. Cut-off voltage The cut-off voltage is divided into the charge cut-off voltage and the discharge cut-off voltage, that is, the voltage at which the battery cannot continue to be charged or discharged. Continued charging or discharging under the cut-off voltage has a great impact on the battery life. The end-of-charge voltage of lithium-ion batteries is generally 4.2v, and the end-of-discharge voltage is 3.0v. It is strictly forbidden to deeply charge or discharge lithium-ion batteries that exceed the terminal voltage. The remaining capacity SOC (state of charge) refers to the percentage of the remaining battery power to the total power, 0~100%. Reflect the remaining battery power. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.