Battery Tab Laser Weld Inspection Application

Because battery tabs conduct electricity and connect cells together, they are fundamental to a battery cell’s overall efficiency, safety, and longevity. This application focuses on battery tab inspection after they’re welded to electrodes using the laser welding technique.

What manufacturing defects occur?

Laser welding is a precise and efficient method for attaching tabs to battery electrodes, but like any manufacturing process, it can introduce defects that could compromise the battery's quality such as:

Defect Description Consequence
Missing or Incomplete Welds Insufficient welds between tab and electrode or missing welds all together Weakened joint; Poor electrical conductivity
Burn Through Holes from laser beams melting through the tab Scrapped tab
Thermal Damage Burn marks on the tabs due to excessive heat Damaged battery materials
Cracks Formation of cracks Compromised joint integrity and strength
Porosity Small voids or air pockets Weakened joints; Reduced mechanical strength
Splatter Molten metal particles ejected from the weld pool Contamination and damaged components
Misalignment Misaligned joints Weak or incomplete weld
Tab tears Cracks or tears in tabs Reduced mechanical strength

These defects can impact the quality, safety, and performance of lithium-ion battery cells, making it crucial for manufacturers to implement rigorous quality control measures and inspection processes to detect and rectify these issues during production.

However, battery tab laser welding defects are difficult to detect. Tabs are made of metal components with reflective surfaces, making defects hard to see. Traditional machine vision systems can fail to distinguish between reflective surfaces and actual defects, causing both false positives and escapes.

Battery tab defects manifest in various shapes, sizes, and locations. Weld patterns can vary significantly based on the specific welding parameters and materials used. And as battery technology evolves, their manufacturing processes change. Traditional machine vision requires programming hundreds of hand-crafted rules, causing them to fail to detect new or variable defects and patterns that don’t match their programmed parameters and making them slow to adapt to changes.

The Solution

UnitX’s AI-powered inspection effectively detects laser welding defects where other solutions fail. 

First, the OptiX imaging system illuminates and images welded joints. Then, the CorteX Central AI platform is trained on laser welding defects. Lastly, those AI models are deployed to the CorteX Edge inference system to detect and classify defects in-line.

Why UnitX for battery tab laser welding inspection?

OptiX provides superior images that minimize reflectivity while maximizing defect visibility. It has 32 independently controllable lighting sources that can be optimized for battery weld surfaces and defects via software. Its computational imaging capability can be used to take multiple shots and eliminate hotspots caused by highly reflective battery weld surfaces. And its lighting dome design supports a very acute incidence angle of projected light, causing even very tiny defects to cast shadows which increase their visibility.

CorteX accurately detects random, complex defects. It automatically normalizes for variability in positions and orientations and recognizes defects down to the pixel-level.

UnitX supports fast experimentation and adapts to changes in production environments. OptiX lighting is easily configured via software and CorteX AI models are sample efficient– they only require a few images to train on new defect types.

With UnitX, manufacturers automate battery tab laser weld inspection to:

  • Prevent quality escapes that cause degraded battery performance and failure, safety risks, and costly recalls
  • Minimize false rejection rates common with traditional machine vision, reducing scrap and wasted materials
  • Replace manual inspectors, saving manufacturers money and improving efficiency

UnitX Inspection Example Deep Dive

In this example, we inspected tab laser weld joints.


First, we used OptiX to capture images of the tab weld joints, making sure we captured both defective and OK parts.


Next, we used CorteX Central to train our models. We created a label for each defect we want to detect: porosity, burn marks, splatter, missing welds, and misaligned welds. 

We then labeled those defects in the images we captured from OptiX, using just a few images of each of the 5 defects.


Next, we deployed the AI models to CorteX Edge on new cells, resulting in the accurate detection and classification of our 5 tab laser weld defects.

Example of weld porosity / blow hole defects detected by UnitX

To learn more about how UnitX can automate inspection for you, please contact us here