7 Steps to Determine the Quality of Lithium Batteries

1. The capacity of lithium -ion batteries


The battery capacity is divided into a rated capacity and actual capacity. The rated capacity of the battery refers to the battery of 5C at the condition that the battery is at a 5C multiplier to the end voltage at the condition of the ambient temperature at 20 ℃ ± 5 ℃. The actual capacity of the battery refers to the actual power released by the battery under a certain discharge condition, which is mainly affected by the discharge multiplier and temperature (therefore, strictly speaking, the battery capacity should refer to the charging conditions). Capacity unit: MAH, AH (1AH = 1000mAh).


2. Internal resistance of lithium -ion battery battery


The internal resistance of the battery refers to the resistance that the battery flows through the battery during working. There are two parts: Om internal resistance and polarization internal resistance. The large resistance value of the battery will cause the battery discharge work voltage to decrease, and the discharge time will be shortened. The internal resistance size is mainly affected by factors such as the material, manufacturing process, and battery structure of the battery. Internal resistance is an important parameter for measuring the performance of the battery.


3. The voltage of the lithium -ion battery


The opening voltage refers to the difference between the battery without current flow when the circuit has no current in the non -working state, and the potential difference between the battery positive and negative electrodes. Under normal circumstances, the lithium -ion battery is about 4.2V after full charging, and the opening voltage after discharge is about 3.0V. The battery can be judged by the battery opening voltage detection.


The working voltage, also known as the end voltage, refers to the difference between the battery in the working state that there is a current flow of the current in the working state, that is, the current current is outdated. In the working state of the battery discharge, when the current flows inside the battery, there is no need to overcome the resistance of the battery's internal resistance. Therefore, the working voltage is always lower than the opening voltage, and the opposite is opposite when charging. The discharge work voltage of the lithium -ion battery is about 3.6V.


4. During the discharge platform time of lithium -ion batteries


The discharge platform time refers to discharge time to discharge until a voltage at a full battery. For example, the 3.6V discharge platform time is measured for a ternary battery, with a constant voltage charging to a voltage of 4.2V, and the charging current is less than 0.02C, which is fully charged. The discharge time when the discharge to 3.6V is the discharge platform time under the current. Because the working voltage of electrical appliances using lithium ion batteries has voltage requirements. If it is lower than the required value, it will not work. Therefore, the discharge platform is one of the important criteria for measuring the performance of battery.


5. Charge and discharge multiplier of lithium -ion batteries


The charging power multiplied rate refers to the current value required when the battery is released when the rated capacity is released within the specified time. The 1C is equal to the battery rated capacity in terms of value, which is usually represented by letters C. For example, the nominal capacity of the battery is 10AH, then 10A is 1C (1 times), 5A is 0.5C, and 100A is 10C, and so on.


6. Self -discharge rate of lithium ion battery


The self -discharge rate, also known as the power maintenance capacity, refers to the ability to maintain the battery stored by the battery under a certain conditions when the battery is opened. It is mainly affected by factors such as the manufacturing process, materials, and storage conditions of the battery. It is an important parameter to measure battery performance.


The charging efficiency refers to the degree of chemical energy that the battery consumes into the chemical energy that the battery can be stored into the battery during the charging process. It is mainly affected by battery technology, formula and battery working environment temperature. The higher the general environmental temperature, the lower the charging efficiency.


The discharge efficiency refers to the ratio of the actual power released by discharge to the end of the voltage under a certain discharge condition to the rated capacity of the battery. The lower the discharge efficiency. The lower the temperature, the lower the discharge efficiency.


7. The cycle life of lithium ion battery


The battery cycle life refers to the number of charging and discharge of the battery under the power discharge system when the battery capacity drops to a certain specified value. The lithium -ion battery GB stipulates that the capacity maintenance rate is more than 60%after the battery cycle is 500 times under 1C.

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