The secondary sealing process in the production of polymer lithium batteries.

The secondary sealing process in the production of polymer lithium batteries.

Polymer lithium batteries generate gas during the production process, so we need to extract the gas before conducting a second encapsulation. When sealing, it can be divided into two processes: degassing and sealing, as well as the subsequent process of cutting the airbag. Generally, these operations are carried out in the same process and can be completed on one device. We call this process sealing.

When sealing, the airbag is first punctured by a guillotine and evacuated, so that the gas and a small portion of the electrolyte in the airbag can be extracted. Then immediately use a double sealed head to package the battery cell in the double sealed area to ensure its airtightness. Finally, cut off the airbag from the packaged battery cell, and a soft pack lithium battery cell is basically formed. The second sealing is the final packaging process of polymer lithium batteries, and its principle is still the same as the previous thermal sealing, because the aluminum-plastic film on the edge of the second sealing will retain electrolyte (which will take away some heat during packaging), and the temperature during packaging is about 10-15 ℃ higher than that of the side sealing edge. It should be noted that if the second edge is not sealed properly, it is also prone to leakage and swelling.