Lithium-ion Battery Tab Geometry for Nondestructive Line Identification
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Solution Overview
Problem
Conventional lithium-ion secondary batteries face challenges in nondestructive traceability, requiring battery disassembly and increasing production costs due to the difficulty in identifying the production line that assembled a defective battery, which can lead to safety issues and inefficiencies.
Innovation Solution
The battery design incorporates a power generating element with positive and negative electrode tabs having arc-like or geometric shapes varying by production line, allowing nondestructive identification using X-ray inspection, eliminating the need for additional identifier steps and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a number or figure is impressed on a tab or current collector as an identifier, then traceability is improved, but nondestructive identification becomes difficult and production steps increase
Solution Approach 1:
The patent applies asymmetry by giving different geometric shapes to electrode tabs from different production lines. Instead of using symmetric identifiers like numbers or figures that require additional marking steps, each production line produces tabs with unique asymmetric geometries (different numbers of notches, protrusions, or angular configurations). This allows traceability to be achieved through the inherent asymmetric shape of the tab itself, enabling nondestructive identification by simply observing the tab geometry without needing to break open the battery or add separate identifier components.
Solution Approach 2:
The patent applies local quality by modifying only the local geometry of the electrode tab at specific locations (such as adding notches, protrusions, or changing angular configurations at the tab edges) while keeping the rest of the battery structure unchanged. This localized geometric modification provides production line identification without requiring changes to the overall battery design or additional identifier components, thus maintaining ease of nondestructive identification while achieving traceability.
2Loss of information
If a number or figure is impressed on a tab or current collector as an identifier, then traceability is improved, but production steps and unit cost increase
Solution Approach 1:
The patent merges the traceability function with the existing electrode tab structure by incorporating geometric shape variations directly into the tab design. Instead of adding separate identifier components or marking steps, the production line identification is combined with the tab's inherent geometry. The same tab that serves its primary electrical function also serves as the identifier through its unique shape, eliminating the need for additional identifier components and reducing production steps.
Solution Approach 2:
The patent applies universality by making the electrode tab serve multiple functions: its primary electrical connection function and its traceability identification function. The geometric variations in the tab shape allow it to simultaneously perform as both an electrical conductor and a production line identifier. This multi-functionality eliminates the need for separate identifier components and reduces the overall number of production steps required.
3Reliability
If the battery is tightly sealed for safety, then reliability is improved, but breaking up the battery for identification becomes troublesome and may cause short circuits
Solution Approach 1:
The patent extracts the identification information from the interior of the sealed battery and places it on the external electrode tab that protrudes from the battery casing. By moving the identifier (the geometric shape) to an externally accessible location on the tab, the identification can be performed nondestructively without breaking the battery seal. This maintains the reliability benefits of tight sealing while enabling easy identification through external observation of the tab geometry.
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 accurate identification of the production line that assembled the battery without disassembly, enhancing traceability and safety while maintaining the existing production steps and costs.
Implementation Method 1
where the one end of the positive electrode tab and/or the negative electrode tab can be recognized by an X-ray inspection apparatus
Data Source
AI summary
A lithium-ion secondary battery is provided where the production process line that fabricated it can be identified. The lithium-ion secondary battery includes a jelly roll, a positive electrode tab, a negative electrode tab, a positive electrode can, and a lid. The jelly roll is made by rolling the positive electrode and the negative electrode with an interposed separator, and is contained in the casing. The positive electrode tab has one end connected to the positive electrode of the jelly roll and the other end connected to the lid. The negative electrode tab has one end connected to the negative electrode of the jelly roll and the other end connected to a terminal provided on the lid. The other end of the negative electrode tab has a shape with a cut at a cut angle determined in accordance with the production process line that fabricated the lithium-ion secondary battery.