Lithium battery pack production process -Lithium - Ion Battery Equipment
The important process parameters of hot-pressing shaping of cells are pressurization pressure, pressurization time and template temperature. Under suitable process parameters, there is almost no air inside the thick cell, the diaphragm and the pole piece are tightly bonded together, and the loose cell can become a hard block. In the process determination test, the test items include the gas permeability and thickness change of the diaphragm; whether the thickness of the cell meets the requirements for entering the shell; whether the pole piece is broken, etc.(Lithium - Ion Battery Equipment)
As the core component of the lithium-ion battery pack, the battery separator plays a key role in isolating the positive and negative electron conduction, while allowing lithium ions to pass back and forth between the two electrodes. Its permeability will directly affect the performance of the battery. The permeability of the diaphragm refers to the amount of gas that the diaphragm passes through under a certain time pressure. If the air permeability of the separator is not good, it will affect the transfer of lithium ions between the positive and negative electrodes, and then affect the charging and discharging of the lithium ion battery.
The testing process is as follows: fix the battery diaphragm, apply air pressure on one side of the diaphragm, measure the pressure drop of the air pressure and the time used, and detect the air permeability of the diaphragm. The shorter the time used, the better the air permeability. During the hot pressing process, the diaphragm may be severely compressed, and the thickness of the diaphragm changes greatly, causing the micropores to be blocked, and the diaphragm will become transparent when observed with the naked eye. transmission. The wound cell is shown in the figure.
If the pole piece is relatively brittle, the battery cell is prone to powder loss or even breakage during the hot-pressing shaping process, which will limit the electron transmission and increase the internal resistance of the battery. Therefore, cell thermoforming must also prevent this from happening. These two aspects require that the smaller the hot-pressing pressure, the better, and the shorter the time, the better.
As the core component of the lithium-ion battery pack, the battery separator plays a key role in isolating the positive and negative electron conduction, while allowing lithium ions to pass back and forth between the two electrodes. Its permeability will directly affect the performance of the battery. The permeability of the diaphragm refers to the amount of gas that the diaphragm passes through under a certain time pressure. If the air permeability of the separator is not good, it will affect the transfer of lithium ions between the positive and negative electrodes, and then affect the charging and discharging of the lithium ion battery.
The testing process is as follows: fix the battery diaphragm, apply air pressure on one side of the diaphragm, measure the pressure drop of the air pressure and the time used, and detect the air permeability of the diaphragm. The shorter the time used, the better the air permeability. During the hot pressing process, the diaphragm may be severely compressed, and the thickness of the diaphragm changes greatly, causing the micropores to be blocked, and the diaphragm will become transparent when observed with the naked eye. transmission. The wound cell is shown in the figure.
If the pole piece is relatively brittle, the battery cell is prone to powder loss or even breakage during the hot-pressing shaping process, which will limit the electron transmission and increase the internal resistance of the battery. Therefore, cell thermoforming must also prevent this from happening. These two aspects require that the smaller the hot-pressing pressure, the better, and the shorter the time, the better.
