Soft Battery Airtightness Inspection via Optical Shape Analysis
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Solution Overview
Problem
Existing airtightness inspection methods for soft package type sealed batteries, particularly those made of deformable materials like laminated films, face challenges in achieving high precision due to invisible crease-like unevenness and individual thickness differences, which affect dimension measurements and accuracy.
Innovation Solution
An airtightness inspection method and apparatus that encloses the sealed battery in an airtight container, measures its surface shape at atmospheric pressure and in a decompressed state under controlled negative pressure, using a CCD camera to capture and analyze images for luminance changes, determining airtightness based on surface shape changes, thereby eliminating the influence of creases and thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dimension measurement is used to inspect airtightness, then inspection method is simple, but inspection precision is low due to invisible creases and thickness variations
Solution Approach 1:
The patent replaces mechanical dimension measurement with optical imaging using a CCD camera. The imaging system captures surface shape information optically, avoiding the limitations of mechanical contact measurement. This substitution enables detection of subtle surface changes caused by airtightness issues without being affected by creases or thickness variations, thereby improving inspection precision while maintaining system simplicity.
Solution Approach 2:
The patent changes the measurement parameter from absolute dimension to surface shape profile. By measuring the shape profile at multiple positions and comparing relative changes, the system can detect airtightness issues caused by internal pressure changes without being influenced by absolute dimensional variations due to creases or thickness differences. This parameter transformation resolves the contradiction by improving precision through differential measurement.
2Ease of manufacture
If battery case is made of deformable laminated film, then manufacturing flexibility is improved, but dimension stability deteriorates due to crease formation
Solution Approach 1:
Instead of trying to prevent crease formation or maintain absolute dimensional stability, the patent inverts the approach by using the surface shape profile as the measurement reference. By measuring relative shape changes at multiple positions and comparing them, the system can detect airtightness issues without being affected by the presence of creases. This inversion transforms the problem from preventing deformation to utilizing deformation patterns for detection.
Solution Approach 2:
The patent transitions from one-dimensional absolute dimension measurement to multi-dimensional surface shape profiling. By capturing the shape profile across multiple positions and analyzing relative changes in this additional dimensional space, the system can distinguish between normal manufacturing variations (creases, thickness differences) and actual airtightness defects, thereby maintaining manufacturing flexibility while achieving dimensional stability in measurement.
3Measurement precision
If surface shape measurement is used instead of dimension measurement, then airtightness detection accuracy is improved, but measurement system complexity increases
Solution Approach 1:
The patent uses a CCD camera to create an optical copy (image) of the battery case surface shape. This optical copying allows non-contact, high-precision measurement of the surface profile without physical interference. The captured images are then processed to extract shape information, providing accurate airtightness detection while avoiding the complexity of mechanical measurement systems through the use of optical field copying.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables highly accurate airtightness inspection by precisely detecting invisible creases and thickness variations, improving detection precision and efficiency, especially for soft packaged sealed batteries, such as those used in automotive secondary batteries.
Implementation Method 1
decompressing the airtight container is performed under a predetermined negative pressure
Implementation Method 2
the battery case being made of a film and easily deformed
Implementation Method 3
using a CCD camera to capture and analyze images for luminance changes
Data Source
AI summary
A soft packaged sealed battery is contained in an airtight container. The airtight container is decompressed and images of the surface shape of the sealed battery in the airtight container before and after decompression are captured by a CCD camera or the like. Whether or not airtightness of the sealed battery is maintained is determined based on a change in the captured images, e.g. a change in the surface shape appearing as luminance differences of pixels. By this determination method, highly accurate airtightness determination is realized by eliminating the influence of invisible fine creases on a sealed battery surface.