Dimension & CCD Inspection Defects in Li-ion Pouch Cell Manufacturing

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Dimension & CCD Inspection Defects in Li-ion Pouch Cell Manufacturing

In lithium-ion pouch cell manufacturing, dimensional accuracy and visual inspection are critical quality parameters. CCD vision systems are commonly used during the final stages of pouch cell assembly to verify important dimensions and visual characteristics.

These systems can inspect parameters such as cell dimensions, seal geometry, tab position, barcode quality, and other reference features. Dimensional deviations can create problems during automated handling, module assembly, and downstream processing.

Common Dimension & CCD Inspection Defects

1. Cell Length Out of Specification

Cell length deviation occurs when the overall cell length is outside the specified tolerance.

Possible Causes:

  • Incorrect side-cutting position
  • Cutting blade misalignment
  • Mechanical drift in the trimming station
  • Laminate stretching during sealing

Potential Impact: Difficulty during module stacking, assembly mismatch, and dimensional rejection.

2. Sealant Height Variation

Sealant height refers to the vertical dimension of the sealed region. Variation may indicate inconsistency in the sealing process.

  • Uneven sealing pressure
  • Improper sealing-bar alignment
  • Incorrect jelly roll positioning
  • Laminate thickness variation

Potential Impact: Weak sealing areas and increased electrolyte-leakage risk.

3. Tab Distance Mismatch

Tab distance represents the spacing between the positive and negative terminals.

  • Jelly roll position shift
  • Tab bending during handling
  • Improper tab positioning

Potential Impact: Electrical connection problems, module assembly issues, and increased short-circuit risk.

4. Degassing Side Length Error

The degassing region is designed for gas removal during formation. Dimensional errors can affect fixture compatibility and downstream processing.

5. Side Corner Damage

Side corners can be damaged during trimming and transfer operations.

  • Improper cutting blade condition
  • Mechanical contact during transfer
  • Excessive trimming pressure

Potential Impact: Laminate cracking and reduced pouch mechanical strength.

6. Degassing Corner Defect

Damage or improper formation near the degassing corner can interfere with the degassing operation and may increase leakage risk.

7. Slot Mark Position Error

Slot marks are reference features used for alignment during downstream operations. Position errors can cause alignment problems in automated assembly.

8. Barcode Dimension Error

Barcode dimensions must remain within the required specification for reliable scanning.

  • Incorrect printer resolution
  • Barcode scaling error
  • Surface deformation
CCD Inspection Control: Regular CCD calibration, stable mechanical alignment, correct lighting and camera settings, and controlled process parameters are essential for reliable inspection results.

Conclusion

CCD inspection provides an important quality gate in pouch cell manufacturing. Detecting dimensional and visual defects before cells move to downstream processes helps reduce rejection, assembly problems, and quality-related losses.

#BatteryManufacturing #CCDInspection #MachineVision #LithiumIonBattery #PouchCell #QualityControl #BatteryEngineering

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