This machine tests the battery cover and container after the heat sealing to make sure they are airtight. If no anomalies are detected, it proceeds to engrave the manufacturing code.
After the battery has been sealed, it will be conveyed to this machine. The testing device will press tightly on the holes on the battery cover and suck air for testing leakages. If it is not airtight, the machine will alarm and it will be rejected immediately; if qualified, it will be sent to the next station for stamping the code.