Lithium battery science I Lithium ion battery common terms Explanation (2)
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2024/03/09 11:36:46
Lithium-ion battery is mainly composed of positive electrode, negative electrode, electrolyte, diaphragm, in addition to the battery also includes binder, conductive carbon black, fluid collection, pole lug, packaging materials and other components.
Constant current (CC)
Provide a steady current for the purpose of charging or discharging the battery
Constant current charging and discharging is to connect the battery to a constant current source or a constant load, limiting the battery current within a safe range until the charging voltage or discharge voltage reaches the limit, in order to ensure the stability and safety of the charging and discharging process, while extending the battery life.
self-discharge
Self-discharge impairs battery performance
Overdischarge caused by excessive self-discharge of lithium-ion batteries will cause irreversible effects on the battery, even if recharged, the available capacity and life of the battery will be greatly reduced. Therefore, lithium-ion batteries that are not used for a long time must be charged regularly to avoid overdischarge caused by self-discharge that damages battery performance.
overdischarge
Excessive discharge of the battery reduces the battery life
When the battery is discharged, the voltage gradually decreases, and the discharge should be stopped and recharged when it falls to the specified value. If the discharge continues below the specified value, it is excessive discharge, which may damage the electrode active substance and reduce the life of the battery.
overcharge
Overcharging damages the battery
After the battery reaches the full charge state, it exceeds the battery charging cutoff voltage value, and overcharging causes the internal pressure of the battery to rise, battery deformation, and liquid leakage, and the performance of the battery will also be significantly reduced and damaged.
Trickle charge
Trickle charging and its application scenarios
Charge a battery with a small current, often used before charging the battery (if the battery cell has fallen below the minimum permissible voltage value).
Discharge depth
Discharge depth and its influence on battery life
The depth of discharge is commonly expressed as DOD(depth of discharge), which is a measure of the degree of discharge, and reflects the proportion of active materials involved in the reaction.
Coulomb efficiency
Coulomb efficiency and its influencing factors
Under certain charging and discharging conditions, the percentage of the charge released by the discharge and the charge charged during charging. The coulomb efficiency is affected by many factors, such as the decomposition of electrolyte, the passivation of electrode interface, and the change of structure, morphology and conductivity of electrode active material.
Internal resistance of battery
The internal resistance of the battery includes ohm resistance and polarization resistance
Ohm resistance is composed of electrode material, electrolyte, diaphragm, fluid collector resistance and contact resistance between components, polarization resistance refers to the resistance caused by polarization during electrochemical reaction, including electrochemical polarization and concentration polarization caused by resistance.
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