What is the capacity of a battery?
The capacity of a battery can be divided into rated capacity and actual capacity. The rated capacity of a battery refers to the minimum amount of electricity that should be discharged under certain discharge conditions, which is stipulated or guaranteed when the battery is designed and manufactured. The IEC standard stipulates that the amount of electricity discharged by nickel-cadmium and nickel-metal hydride batteries under 20℃±5℃ environment at 0.1C for 16 hours and then discharged at 0.2C to 1.0V is the rated capacity of the battery, expressed as C5. For lithium-ion batteries, it is stipulated that the amount of electricity discharged when charged for 3 hours at room temperature, constant current (1C)-constant voltage (4.2V) controlled, and then discharged at 0.2C to 2.75V is the rated capacity, while the actual capacity of a battery refers to the actual amount of electricity discharged by the battery under certain discharge conditions, which is mainly affected by the discharge rate and temperature (so strictly speaking, the battery capacity should indicate the charging and discharging conditions). The units of battery capacity are Ah, mAh (1Ah=1000mAh).
What are the main structural components of lithium-ion batteries?
The main components of lithium-ion batteries are: upper and lower battery covers, positive electrode sheets (active material is lithium cobalt oxide), diaphragms (a special composite membrane), negative electrodes (active material is carbon), organic electrolytes, battery shells (divided into steel shells and aluminum shells), etc.
What is the electrochemical principle of lithium-ion batteries?
The main component of the positive electrode of lithium-ion batteries is LiCo02, and the negative electrode is mainly C. When charging,
Positive electrode reaction: LiCo02-Li1-xCo02+xLi++xe-
Negative electrode reaction: C+xLi++xe-→ CLix
Total battery reaction: LiCo02+C-Li1-xCo02+CLix
The reverse reaction of the above reaction occurs during discharge.
What is pulse charging? What is the impact on battery performance?
Pulse charging generally adopts the method of charging and discharging, that is, charging for 5 seconds and discharging for 1 second. In this way, most of the oxygen generated during the charging process will be reduced to electrolyte under the discharge pulse. Not only does it limit the gasification amount of the internal electrolyte, but also for those old batteries that have been severely polarized, after charging and discharging 5-10 times using this charging method, they will gradually recover or approach the original capacity.
What is discharge efficiency?
Discharge efficiency refers to the ratio of the actual amount of electricity discharged to the terminal voltage under certain discharge conditions to the rated capacity. It is mainly affected by factors such as discharge rate, ambient temperature, and internal resistance. Generally speaking, the higher the discharge rate, the lower the discharge efficiency. The lower the temperature, the lower the discharge efficiency.