1. How are the safety features of lithium-ion realized?

a. The diaphragm automatically shuts off protection at 135°C and adopts the international advanced Celgars2300PE-PP-PE three-layer composite film. When the temperature of the battery reaches 120°C, the membrane pores on both sides of the PE composite film are closed, the internal resistance of the battery increases, and the internal temperature of the battery slows down. When the temperature of the battery reaches 135 ℃, the PP film hole is closed, the internal circuit of the battery is disconnected, and the battery no longer heats up, ensuring the safety and reliability of the battery.

b. Adding additives to the electrolyte. Under the condition that the battery is overcharged and the battery voltage is higher than 4.2V, the electrolyte additives will polymerize with other substances in the electrolyte, the internal resistance of the battery will increase greatly, and a large-area open circuit will be formed inside the battery. Warm up again.

c. Battery cover composite structure The battery cover adopts a scored explosion-proof ball structure. When the battery heats up, part of the gas generated during the internal activation of the battery expands, the internal pressure of the battery increases, and the pressure reaches a certain degree of score cracking and deflation.

d. Various environmental abuse tests Carry out various abuse tests, such as external short circuit, overcharge, acupuncture, impact, incineration, etc., to investigate battery safety performance. At the same time, the battery is subjected to temperature shock experiments and mechanical performance experiments such as vibration, drop, and impact to investigate the performance of the battery in the actual use environment.

2. Why does the constant voltage charging current gradually decrease?
Because when the constant current process is terminated, the electrochemical polarization inside the battery remains at the same level in the entire constant current. During the constant voltage process, and under the action of a constant electric field, the internal Li+ concentration polarization is gradually eliminated, and the number of ion migration And the speed is shown as the current gradually decreases.
3. What is the capacity of the battery?

The capacity of the battery is divided into the rated capacity and the actual capacity. The rated capacity of the battery refers to the stipulation or guarantee that the battery should discharge the minimum amount of electricity under certain discharge conditions during the design and manufacture of the battery. Li-ion stipulates that the battery is charged for 3 hours under the control of normal temperature and constant current (1C) and constant voltage (4.2V). The actual capacity of the battery refers to the actual power released by the battery under certain discharge conditions, which is mainly affected by the discharge rate And temperature (so strictly speaking, the battery capacity should specify the charging and discharging conditions). Common units of capacity are: mAh, Ah=1000mAh).

4. What is the internal resistance of the battery?
It refers to the resistance experienced by the current flowing through the battery when the battery is working. It is composed of ohmic internal resistance and polarization internal resistance. The large internal resistance of the battery will reduce the battery discharge working voltage and shorten the discharge time. The internal resistance is mainly affected by the battery material, manufacturing process, battery structure and other factors. It is an important parameter to measure battery performance.
Note: Generally, the internal resistance in the charged state is the standard. To measure the internal resistance of the battery, a special internal resistance meter should be used instead of a multimeter in the ohm range.
5. What is open circuit voltage?
The open circuit voltage after fully charged is about 4.1-4.2V, and the open voltage after discharge is about 3.0V. Through the open circuit voltage of the battery, the state of charge of the battery can be judged. What is the working voltage? The discharge working voltage is about 3.6V.
6. What is the internal pressure of the battery?
Refers to the internal air pressure of the battery, which is caused by the gas generated during the charging and discharging of the sealed battery, and is mainly affected by factors such as battery materials, manufacturing processes, and battery structure. The main reason for this is that the gas generated by the decomposition of moisture and organic solution inside the battery accumulates in the battery. High-rate continuous overcharge will cause the battery temperature to increase and the internal pressure to increase. In severe cases, it will have a destructive effect on the performance and appearance of the battery, such as leakage, drum bottom, increase in battery internal resistance, discharge time and cycle life Shorten etc. Any form of Li-ion abuse will cause serious damage to battery performance and even explosion. Help Li-ion to use constant current and constant voltage charging during the charging process to avoid overcharging the battery.
7. Why do the batteries need to be stored for a period of time before they can be packaged and shipped?
The storage performance of the battery is an important parameter to measure the stability of the overall performance of the battery. After the battery has been stored for a certain period of time, the capacity and internal resistance of the battery are allowed to change to a certain extent. After a period of storage, the electrochemical performance of the internal components can be stabilized, and the self-discharge performance of the battery can be understood to ensure the quality of the battery.
8. Why is it formed?

After the battery is manufactured, the internal positive and negative materials are activated through certain charging and discharging methods to improve the charging and discharging performance of the battery and the process of self-discharge, storage and other comprehensive performance is called chemical conversion. The battery powder can only reflect the true performance after chemical conversion.

9. What is capacity division?
During the manufacturing process of the battery, the actual capacity of the battery cannot be completely consistent due to technological reasons. The process of testing through a certain charge and discharge system and classifying the battery according to the capacity is called capacity division.
10. What is pressure drop?
The battery is qualitatively charged to more than 80%, and the no-load voltage of the battery is measured. The 5W/2W battery is used as a load to connect the positive and negative terminals of the battery as the open circuit of the battery, and the connected devices are connected in series. The voltage drop should not exceed 0.4V within 5 seconds after the switch is turned on, and it is mainly for testing the battery load performance to be qualified.
11. What is static resistance? What is dynamic resistance?
a. Static resistance is the internal resistance of the battery during discharge.
b. Dynamic resistance is the internal resistance of the battery during charging.
12. What welding method is used for the positive and negative electrodes?
a. Ultrasonic welding machine for positive electrode.
b. Spot welder for negative electrode.
13. The purpose and location of the adhesive tape on the battery core?
a. The position of the battery core sticker will not be deformed after the battery core is wound into shape. Adhesive paper is attached to the bottom to prevent the bottom of the positive electrode in the battery cell from contacting the battery and causing a short circuit.
b. The side sticker makes the battery core not deformed after winding and forming. Adhesive paper is attached to the bottom to prevent the bottom of the positive electrode in the battery cell from contacting the battery shell and causing the battery to short circuit.
14. What is the humidity requirement of the drying room? Why is the battery weighed before filling?
a. The relative humidity is below 6%.

b. Weigh in order to accurately calculate the amount of liquid injected.