Rechargeable Battery Lead Tab Structure for Lower Connection Resistance
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Solution Overview
Problem
The connection of an uncoated portion and a lead tab in rechargeable batteries results in increased electrical resistance, hindering high output performance.
Innovation Solution
A rechargeable battery design featuring a lead tab composed of a first tab with a specific width and thickness, connected to an uncoated portion, and a second tab with a smaller width but greater thickness, which is connected to the first tab, reducing electrical resistance through surface contact and partial protrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple single-tab lead tab structure is used, then the device complexity is low, but the electrical resistance at the connection portion increases
Solution Approach 1:
The lead tab is divided into a first tab connected to the uncoated portion and a second tab connected to the first tab, creating a segmented structure. This segmentation allows for optimized electrical connection by separating the connection functions, thereby reducing electrical resistance at the connection portion while maintaining manageable structural complexity
Solution Approach 2:
The second tab extends in a direction substantially perpendicular to the width direction of the first tab, adding a dimensional aspect to the connection structure. This dimensional change creates additional contact area and alternative current pathways, reducing electrical resistance without significantly increasing overall structural complexity
2Reliability
If the lead tab has uniform thickness, then the manufacturing process is simple, but the electrical resistance cannot be optimized
Solution Approach 1:
The lead tab structure implements local quality by making the second tab thicker than the first tab in specific regions. This localized thickness variation optimizes electrical resistance at the connection portion where higher current density occurs, while maintaining simpler geometry in other areas to facilitate manufacturing
Solution Approach 2:
The thickness parameter of the lead tab is changed locally in the second tab to optimize electrical performance. By increasing the thickness in specific regions rather than uniformly throughout, the design achieves lower electrical resistance while maintaining manufacturing feasibility through controlled parameter variation
3Reliability
If a larger contact area between lead tab and uncoated portion is created, then electrical resistance decreases, but the device complexity increases
Solution Approach 1:
The connection structure is segmented into multiple tabs rather than using a single large-contact structure. The first tab provides initial connection to the uncoated portion, while the second tab extends perpendicular to provide additional contact area, achieving reduced electrical resistance through distributed contact rather than a single complex large-area connection
Solution Approach 2:
Instead of increasing contact area in the same plane which would require larger dimensions and more complex positioning, the second tab extends in a perpendicular direction. This dimensional change creates additional contact area in three-dimensional space, reducing electrical resistance without requiring a larger footprint or more complex planar arrangement
Data Source
AI summary
An aspect of the present invention is to provide a rechargeable battery that implements a high output of an electrode assembly by reducing electrical resistance at a connection portion of a uncoated portion and a lead tab. A rechargeable battery according to an embodiment of the present invention includes: an electrode assembly wound by arranging a separator between electrodes; a lead tab connected to the electrode; and a case which accommodates the electrode assembly and of which the lead tab is drawn to the outside, and the lead tab includes a first tab formed with a first width and a first thickness and connected to an uncoated portion of the electrode, and a second tab formed with a second width equal to or less than the first width and a second thickness equal to or more than the first thickness, and connected to the first tab.