Automatic Line for Prismatic Cells Electrical Testing (EOL)

The fully automated machine described is an example of a plant designed to process prismatic cells for the Beginning of Line testing in a Module assembly line. 
The cells are fed by means of trays collected in stacked boxes stored in an automatic warehouse. The automation separates each tray so that it can be handled by a robot whose task is to transfer the cells from the warehouse to the pallet conveyor. The required cycle time makes it necessary to have a certain number of warehouses and corresponding robots working in parallel.

The first inspection station consists of three benches equipped with camera systems to check each side of the cell casing for defects and to determine the orientation of the poles. The rejects are segregated; the good ones are placed back on the conveyor pallet with the correct pole orientation, to move on to the next station thanks to a servo-controlled Cartesian manipulator. The number of benches depends on the expected cycle time.

The second test station consists of a turntable with nests where the OCV/DCIR test is performed thanks to pogo-pin probes. Different type of tests can also be performed, depending on customer’s specification. One set of multiple cells is lifted at a time and surrounded by conductive foam to perform electrical insulation tests (Hi-Pot) on all the cells processed in parallel. A robot transfers the cells to and from the current station.

The third measuring station is dedicated to the evaluation of the thickness of the cells thanks to the application of a precise and preset pressure of the contact probes. The nests are distributed on the edge of a circular turntable.

Finally, the successfully inspected cells are sorted on conveyor belts and the rejects are removed. Again, a robot is used to handle the cells.