Lead Film OCT Inspection for Internal Battery Void Detection
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Solution Overview
Problem
Current methods for inspecting gaps between lead films and lead tabs in lithium-ion batteries are inadequate, as they fail to detect internal gaps accurately, leading to potential electrolyte leakage and safety issues, particularly in pouch-type batteries used in electric vehicles.
Innovation Solution
A device and method utilizing optical coherence tomography (OCT) for inspecting the interface between lead tabs and lead films, including a conveying system, alignment units, OCT scanners, and a gap determiner to analyze images and determine fusion quality, enabling quick and accurate detection of gaps during mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection methods (visual inspection or camera-based vision inspection) are used to detect gaps between lead film and lead tab, then the inspection process is simple, but the detection precision is insufficient and internal gaps cannot be accurately detected
Solution Approach 1:
The patent replaces conventional mechanical or optical vision inspection systems with an ultrasonic inspection system. The ultrasonic inspection device uses acoustic waves to detect internal gaps between the lead film and lead tab, enabling accurate detection of subsurface defects that visual inspection methods cannot identify, thereby resolving the contradiction between detection precision and device complexity.
Solution Approach 2:
The patent introduces an ultrasonic wave as an intermediary medium to detect internal gaps. The ultrasonic inspection device sends ultrasonic waves through the lead film and lead tab assembly, and the reflected waves reveal the presence of gaps. This intermediary approach allows indirect detection of internal structures without requiring direct visual access, improving measurement precision while maintaining manageable device complexity.
2Measurement precision
If sampling inspection by cutting battery sections is used, then internal gaps can be detected, but the productivity is reduced and time consumption increases
Solution Approach 1:
The patent replaces destructive mechanical cutting and sampling inspection with non-contact ultrasonic inspection. The ultrasonic inspection device can scan the entire lead film-lead tab interface rapidly without physical contact or sample preparation, enabling full inspection of all batteries at high speed while maintaining the ability to detect internal gaps, thus resolving the contradiction between detection capability and productivity.
3Reliability
If lead film is attached to prevent electrolyte leakage, then battery safety is improved, but the manufacturing precision requirement increases due to the critical need for complete adhesion
Solution Approach 1:
The patent implements a feedback mechanism where ultrasonic inspection results are used to evaluate the adhesion quality of the lead film to the lead tab. The inspection system provides real-time feedback on gap presence and size, allowing manufacturers to adjust the attachment process parameters to ensure complete adhesion, thereby maintaining high reliability for electrolyte leakage prevention while managing manufacturing precision requirements.
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 allows for comprehensive and precise inspection of gaps, preventing electrolyte leakage and potential battery explosions by identifying and quantifying gap sizes, thereby improving battery quality and reducing defects in the film fusion process.
Implementation Method 1
optical coherence tomography (OCT) for inspecting the interface between lead tabs and lead films
Data Source
AI summary
Proposed are a device and a method for inspecting an air void at a lead film of a battery to simply and accurately perform total inspection of a gap between a lead film and the lead tab boundary by using an OCT, wherein an object to be inspected in which the lead film is attached to a lead tab is conveyed through a conveying device, the conveyed object is gripped and loaded to an inspection position, the object is aligned to form an OCT focus on an interface between the lead tab and the lead film of the object, a gap inspection image between the lead tab and the lead film is obtained by scanning the interface between the lead tab and the lead film by using an OCT scanner above the inspection position, and the obtained gap inspection image is analyzed, thereby determining fusion quality of the lead film.