Electrode Foil Position Detection From Low-Contrast X-Ray CT
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Solution Overview
Problem
Existing X-ray CT analysis methods for power storage devices suffer from low positional resolution and low contrast due to large device dimensions and high-energy X-rays, making it difficult to clearly identify electrode foil positions and distances in tomographic images.
Innovation Solution
A method involving X-ray CT analysis to identify electrode foil positions by fitting an approximate curve to on-path X-ray absorbed amounts, using a specific imaginary line that passes perpendicularly through the electrode sheet, and estimating foil positions from the peak of the curve, allowing for accurate identification of foil positions and calculation of inter-foil distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance from the X-ray source to the power storage device is increased to accommodate large device dimensions, then the device can be inspected, but the positional resolution of the X-ray absorbed amount decreases
Solution Approach 1:
The patent divides the inspection process into two stages: first obtaining low-resolution tomographic images from the entire power storage device, then performing high-resolution line profile measurements along specific paths through the electrode sheets. This segmentation allows the system to handle large devices while achieving high positional resolution at critical locations.
Solution Approach 2:
The patent transitions from two-dimensional tomographic imaging to one-dimensional line profile analysis along specific paths. By extracting and analyzing line profiles through the electrode sheets, the system achieves high positional resolution in the direction perpendicular to the electrode sheets, overcoming the limitations of three-dimensional imaging at large distances.
2Volume of moving object
If high energy X-rays are used to penetrate the power storage device, then the X-rays can pass through the device, but the contrast of the obtained images decreases
Solution Approach 1:
The patent applies different measurement qualities to different regions: high-energy X-rays are used for overall device penetration to obtain tomographic images, while low-energy X-rays or enhanced measurement techniques are applied along specific line paths through the electrode sheets to achieve high contrast and positional resolution for foil identification.
Solution Approach 2:
The patent extracts one-dimensional line profiles from the three-dimensional tomographic data, focusing measurement resources on specific paths through the electrode sheets. This dimensional reduction allows for enhanced contrast and resolution along the measurement paths even when using high-energy X-rays for overall penetration.
3Loss of information
If conventional X-ray CT analysis is used to obtain tomographic images, then the overall device structure can be visualized, but clear peaks indicating foil positions do not appear
Solution Approach 1:
The patent extracts line profiles along specific paths through the electrode sheets from the tomographic images. By focusing on one-dimensional projections through the electrode foils, the method isolates the foil signals and enhances the peaks corresponding to foil positions, making them clearly identifiable despite the low contrast in the full three-dimensional images.
Solution Approach 2:
The patent transforms three-dimensional tomographic data into one-dimensional line profiles along paths perpendicular to the electrode sheets. This dimensional transformation concentrates the foil signals into distinct peaks in the line profiles, enabling clear identification of foil positions that are not visible in the three-dimensional tomographic images.
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
Enables precise identification of electrode foil positions and calculation of inter-foil distances in power storage devices, even with low-resolution X-ray CT analysis, by utilizing symmetric curves to enhance accuracy.
Implementation Method 1
analyzing the power storage device by X-ray CT analysis using irradiation of an X-ray to obtain an X-ray absorbed amount at each of a plurality of positions in the power storage device
Data Source
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AI summary
A method for identifying a foil position in a power storage device (10) includes: analyzing (S1) the power storage device (10) by X-ray CT analysis to obtain an X-ray absorbed amount (AB(r, θ, z)) at each position; acquiring (S2) an on-path X-ray absorbed amount (AB(d)) at each on-path position (d) on a specific imaginary line (HT) passing through an electrode sheet (21, 25); and identifying (S3) a foil position (dpf, dnf) of an electrode foil (22 , 26) through which the specific imaginary line (HT) passes, based on the on-path X-ray absorbed amount (AB(d)). The foil position identifying (S3) includes fitting (S32) to determine an approximate curve (FC6) that changes to fit a change in the on-path X-ray absorbed amount (AB(d)) in a fitting region (AF6) and generates a single peak (FCP6) in the fitting region (AF6), and estimating (S33) a foil position (dpf6) of a single electrode foil (22) from the on-path position (d) corresponding to the single peak (FCP6) of the determined approximate curve (FC6).