Cell manufacturing/EOL Testing

Description

Production process

Before the cells leave the factory, they are tested in an EOL test rig.
The cells are removed from the good carriers in the aging racks and fed to the testing station.
Here they are discharged to the shipping state of charge (capacity measurement).
Depending on the manufacturer, pulse tests, internal resistance measurements (DC), optical inspections, OCV tests and leakage tests are carried out.
After testing, many cell manufacturers sort the cells according to their performance data (grading).
Once the tests have been completed passed successfully, the cells can be packed and shipped.
For transport, the cells are usually provided with a plastic cover and stacked in a cardboard box.

Process parameters & requirements

State of charge of the cell for shipping: 5 % - 20 % SOC
Permissible loss rate: < 5 mV per week
Increased loss rate: > 5mV per week may indicate e.g. cell-internal short circuits

Technology alternatives

Different test sequences and durations exist depending on the cell manufacturer.

Quality influences

Cell handling

Quality characteristics

Low self-discharge
Low internal resistance
Constant capacity

Source

Heimes, H.H.; Kampker, A.; Lienemann, C.; Locke, M.; Offermanns, C.; Michaelis, S.; Rahimzei, E. (2018) Lithium-Ion Battery Cell Production Process; PEM of RWTH Aachen and VDMA, 3rd Edition, ISBN:978-3-947920-03-7

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Outgoing

Subject	Property	Object
Cell manufacturing/EOL Testing	HasPredecessor	Cell manufacturing/Aging
Cell manufacturing/EOL Testing	HasSuccessor	Module manufacturing