In the TWh era, lithium battery manufacturers pursuing extreme production are increasingly stringent in their quality control and safety requirements for production processes, urgently seeking various "remedies" to improve quality and efficiency.

Tiny Burrs, Mighty Menace

To produce batteries of different sizes, electrode sheets that have gone through coating and rolling processes need to undergo slitting and punching. During this process, burrs are easily produced on the cutting edges of the electrode sheets. Excessively long burrs can easily puncture the separator, causing contact between positive and negative electrodes, leading to short circuits, battery performance degradation, and even fire or explosion safety issues.

The persistent nature of this problem is due to the industry's lack of verified and effective detection methods. Even long burrs are only a few microns in size, virtually invisible to the naked eye, with low distribution density and uncontrollable distribution locations, making detection challenging. Before 2023, burr detection on electrode sheets mostly relied on offline sampling inspection using electron microscopes, which couldn't effectively control product quality.

Burr schematic diagram (Note: Schematic from the internet)

To complete defect detection without affecting overall production capacity, inline full inspection is undoubtedly the best solution. However, stably detecting and accurately identifying micron-level burrs in high-speed production conditions, while considering factors such as space and investment, presents numerous challenges.

AI+VISION | Innovation Unleashed: Breaking Through Barriers

As one of the earliest enterprises to enter the machine vision field in China, LUSTER has always adhered to the concept of independent innovation in R&D. We have successively overcome many challenges such as computational imaging and precise imaging, continuously transforming cutting-edge R&D results into practical solutions for solving customer problems. LUSTER has introduced lithium battery burr inline full inspection system and related solutions to tackle the burr detection challenge, cracking this tough industry problem.

High-Speed Autofocus: Nothing Escapes Our Gaze!

LUSTER's independently developed high-speed adaptive auto-focus system enhances the depth of field in imaging. Under conditions of high resolution, large field of view, and extensive depth of field, it achieves a detection resolution of 2μm at speeds of 150m/min. It maintains stable, clear imaging within a 3mm vibration range of electrode sheet materials, completing full inspection of edge burrs.

Adaptive auto-focus animation demonstration

The interface of the inspection system

AI+Vision, Zero Escape: Perfecting Inspection Precision

Having solved the problem of clear visibility, the inspection system also needs to distinguish clearly.

To ensure zero missed detection of burr defects, strict detection parameters need to be set. However, during the electrode sheet slitting and production process, interfering defects such as debris and wavy edges are also encountered. Only by accurately classifying and filtering burrs and interfering defects can the false detection rate be reduced while ensuring zero missed detections, avoiding material waste. Secondly, even among burrs, there are differences in length. AI recognition is needed to identify burr lengths for graded control and processing.

F.Brain is LUSTER's independently developed deep learning AI platform for industrial quality inspection scenarios and has been widely applied in the lithium battery inspection field. In the burr detection scenario, traditional algorithms combined with AI are first used for initial screening of defects, followed by deep learning AI algorithms for distinguishing and precisely identifying detected defects, ultimately achieving zero missed detections with a false positive rate lower than one in a hundred thousand.

Practical Solutions, Real Savings: Turning Burrs into Profit

Passing sampling inspection doesn't mean all products are qualified; defective products can still be released. Taking burrs produced in the slitting process as an example, at a production speed of 100m/min, even after the first "qualified" offline sampling inspection, tens of thousands of meters of defective products can still be produced in a 10-hour shift. Even though brushes can remove some burrs, a single slitting machine may still produce nearly ten thousand meters of defective products, resulting in losses of tens of thousands of yuan.

Missed detection of burr defects seriously erodes enterprise profits.

The installation positions of LUSTER's lithium battery burr inline full inspection system are generally divided into two types:

• Installed after the brush and before waste removal, marking defects after partial burr removal by the brush, ensuring that all marked defects still exist, saving materials.
• Installed near the slitting position to monitor slitting status, enabling early detection and prompt repair, avoiding continuous defective production.

Moreover, LUSTER's lithium battery burr inline full inspection system has a compact overall design layout, easy installation and maintenance, with mature installation solutions for equipment such as roller slitters, slitting machines, die slitters, integrated die-roll machines, and winding machines, covering 90% of market application scenarios. It can truly help customers extract safety and squeeze out profits from these tiny burrs.

Proven Performance: Experience Meets Excellence

After nearly half a year of project cooperation, LUSTER's lithium battery burr inline full inspection system has been verified by a leading industry customer and achieved batch delivery, bridging the last mile from theory to practice and staying ahead in the industry. During the project process, LUSTER not only jointly built a standard machine verification process with the customer but also accumulated mature experience.

Looking to the future, in the face of new changes and demands in the lithium battery industry, LingYun Vision will maintain its technological foundation, deeply explore customer needs, and assist customers in demanding quality from every detail and managing strictly in every link with innovative products and solutions, achieving the goal of zero complaints!