5 core indicators of rechargeable battery parameters

1. It is impossible to accept batteries with unqualified safety performance indicators. The most influential ones are explosions and liquid leakage. The explosion and leakage are mainly related to the internal pressure, structure and process design of the battery (such as safety valve failure, lithium-ion battery without protection circuit, etc.) and improper operation that should be prohibited (such as throwing the battery into a fire). 2. Capacity refers to the total amount of electricity that a battery can release under certain discharge conditions. According to the IEC standard and the national standard, nickel-cadmium and nickel-metal hydride batteries are charged at 0.1C for 16 hours and discharged at 0.2C to 1.0V under the condition of 20±50C, which is the rated capacity of the battery, expressed in C; lithium ion The battery's rated capacity is the battery's rated capacity when the battery is charged for 3 hours under normal temperature, constant current (1C), and constant voltage (4.2V) conditions and then discharged at 0.2C to 2.75V. The unit of battery capacity is mah and Ah (1Ahu003d1000mAh). Taking the AA2300mAh Ni-MH rechargeable battery as an example, it means that when the battery is charged at 230mA (0.1C) for 16 hours and then discharged at 460mA (0.2C) to 1.0V, the total discharge time is 5 hours, and the discharged power is 2300mAah. Correspondingly, if it is discharged with a current of 230 mA, the discharge time is about 10 hours. 3. Internal resistance The internal resistance of a battery refers to the resistance encountered when current flows through the battery. The internal resistance of the rechargeable battery is very small, and a special instrument can be used to measure more accurate results. The internal resistance of the battery generally known is the internal resistance of the charged state, even if the internal resistance of the battery is fully charged (corresponding to the internal resistance of the discharged state, it refers to the internal resistance of the battery after fully discharged. Generally speaking, the internal resistance of the discharged state is more than The internal resistance in the charged state is large and not very stable). The greater the internal resistance of the battery, the more energy the battery consumes, and the lower the efficiency of the battery. A battery with a large internal resistance generates a lot of heat during charging, causing the battery's temperature to rise sharply. The impact on the battery and the charger is great. With the increase in the number of times the battery is used, the internal resistance of the battery will increase to varying degrees due to the consumption of the electrolyte and the decrease in the activity of the internal chemical substances in the battery. The lower the quality of the battery, the faster the rise. 4. Cycle life Cycle life is the number of times the battery can be repeatedly charged and discharged. The battery life and capacity are in an inverse relationship. Generally, the cycle life of a nickel-hydrogen battery can reach more than 500 times. The life of a high-capacity battery is shorter, but it can reach more than 200 times. The cycle life is also closely related to the charging and discharging conditions. Generally, the larger the charging current (the faster the charging speed), the shorter the cycle life. 5. Charge retention capability The charge retention capability, which is usually referred to as self-discharge, refers to the retention capability of the stored power of the battery under certain environmental conditions in an open circuit state. Self-discharge is mainly determined by various factors such as battery materials, manufacturing processes, and storage conditions. Generally, the higher the temperature, the greater the self-discharge rate. A certain degree of self-discharge of rechargeable batteries is normal. Take nickel-metal hydride batteries as an example. The IEC standard stipulates that after the battery is fully charged, at a temperature of 20±5°C and a humidity of 65±20%, the battery should be left open for 28 days, and the 0.2C discharge time shall not be less than 3 hours (that is, the remaining power Greater than 60%). The self-discharge of lithium-ion batteries and dry batteries is much smaller. 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 post: Electrochemical test requirements for 7 large 18650 lithium batteries