What are the performance indicators of lithium batteries
Back
2022/04/20 17:14:11
Important performance indexes of lithium-ion batteries are as follows;
Battery capacity
The capacity of a battery can be rated or actual. The rated capacity of the battery refers to the battery at the ambient temperature of 20℃. At 5℃, the quantity of electricity to be supplied at the discharge rate of 5h to the termination voltage is represented by C5. The actual capacity of the battery refers to the actual power released by the battery under certain discharge conditions, which is affected by the discharge rate and temperature (so strictly speaking, the capacity of the battery should specify the charge and discharge conditions).
Capacity unit: mAh, Ah(1Ah=1000mAh).
The battery internal resistance
Battery internal resistance refers to the resistance of current flowing through the battery when the battery is working. It is composed of ohmic internal resistance and polarization internal resistance. A large battery resistance reduces the battery discharge voltage and shortens the discharge time. The size of the internal resistance is affected by the material, manufacturing process, battery structure and other factors. Battery internal resistance is an important parameter to measure battery performance.
voltage
Open circuit voltage refers to the potential difference between the positive and negative terminals of a battery when it is not working, that is, when there is no current flowing in the circuit. In general, the open-circuit voltage of lithium ion battery is about 4.14.2V after full charge and about 3.0V after discharge. By detecting the open circuit voltage of the battery, the charged state of the battery can be judged.
Working voltage, also known as terminal voltage, refers to the potential difference between the positive and negative terminals of the battery in the working state, that is, when there is current flowing in the circuit. In the battery discharge working state, when the current flows through the battery, there is no need to overcome the resistance caused by the internal resistance of the battery, so the working voltage is always lower than the open circuit voltage, and the opposite is true when charging. The discharge voltage of lithium-ion battery is about 3.6V.
Discharge platform time
Discharge platform time refers to the discharge time when the battery is fully charged to a certain voltage. For example, measure the 3.6V discharge platform time of a teradata battery, charge it at constant voltage until the voltage is 4.2V, and when the charging current is less than 0.02C, stop charging, i.e., charge it fully, and then put it aside for 10 minutes. When the discharge current at any rate is lowered to 3.6V, the discharge time is the discharge platform time of the current.
Because some electric appliances using lithium ion batteries have voltage requirements, if lower than the required value, it will be unable to work. So discharge platform is one of the important criteria to measure battery performance.
Charge and discharge ratio
The charge and discharge rate is the current value required by the battery to discharge its rated capacity within a specified period of time. 1C is equal to the rated capacity of the battery and is usually represented by the letter C. If the nominal rated capacity of the battery is 10Ah, 10A is 1C (1 multiplier), 5A is 0.5C, 100A is 10C, and so on.
self-discharge
Self-discharge rate, also known as charge retention capacity, refers to the battery in the open state, the battery storage capacity under certain conditions. The importance of battery manufacturing process, materials, storage conditions and other factors. Is an important parameter to measure battery performance.
The efficiency of
Charging efficiency is a measure of the extent to which the electric energy consumed in the charging process is converted into the chemical energy stored by the battery. It is mainly affected by the battery technology, formula and working environment temperature of the battery. Generally, the higher the ambient temperature is, the lower the charging efficiency is.
Discharge efficiency refers to the ratio between the actual power released by discharging to the terminal voltage and the rated capacity of the battery under certain discharge conditions. It is affected by discharge rate, ambient temperature, internal resistance and other factors. In general, the higher the discharge rate, the lower the discharge efficiency. The lower the temperature, the lower the discharge efficiency
Previous
