What is battery capacity?
Battery capacity is categorized into rated capacity and actual capacity. Rated capacity refers to the minimum amount of electricity a battery should discharge under specified conditions, as defined during its design and manufacturing. IEC standards define the rated capacity of nickel-cadmium and nickel-metal hydride batteries as the amount of electricity discharged at 0.2C until 1.0V after charging at 0.1C for 16 hours at 20°C ± 5°C. This is denoted as C5. For lithium-ion batteries, the rated capacity is specified as the amount of electricity discharged at 0.2C until 1.0V after charging at 1C for 3 hours under constant voltage (4.2V) control at room temperature and constant current conditions. (1C) to constant voltage (4.2V) for 3 hours, followed by discharge at 0.2C to 2.75V. The actual capacity refers to the actual energy delivered under specific discharge conditions, primarily influenced by discharge rate and temperature (thus, strictly speaking, battery capacity should specify the charge/discharge conditions). Battery capacity units include Ah and mAh (1Ah = 1000mAh).
What does IEC stand for?
The IEC, or International Electrotechnical Commission, is a global standardization organization composed of national electrotechnical committees. Its purpose is to promote standardization in the field of electrical and electronic engineering worldwide. IEC standards are standards developed by the International Electrotechnical Commission.
What is charging efficiency?
Charging efficiency measures the extent to which electrical energy consumed during battery charging is converted into chemical energy stored within the battery. It is primarily influenced by battery manufacturing processes and operating temperature; generally, higher ambient temperatures result in lower charging efficiency.
What is discharge efficiency?
Discharge efficiency is the ratio of the actual electrical energy discharged to the rated capacity when discharging to the end-of-discharge voltage under specified conditions. It is primarily influenced by discharge rate, ambient temperature, and internal resistance. Generally, higher discharge rates result in lower discharge efficiency, and lower temperatures also reduce discharge efficiency.
