Battery Cell Tab Welding Structure for Lower Resistance Paths
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Solution Overview
Problem
Battery cells face challenges in improving overcurrent capability due to high resistance and non-uniform current density caused by limited tab layers that can be welded to the electrode draw-out portion, leading to risks of polarization and reduced charging efficiency.
Innovation Solution
The solution involves welding tab layers that are not connected to the electrode draw-out portion to shorten conductive paths, forming first and second welded portions to reduce resistance and enhance current density uniformity, thereby improving overcurrent capability and charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only limited tab layers are welded to the electrode draw-out portion, then the welding process is simple, but the resistance is high and current density uniformity is poor
Solution Approach 1:
The tab layers are divided into multiple groups, with different numbers of tab layers welded to the electrode draw-out portion. Specifically, a first number of tab layers are welded to form a first welded portion, and a second number of tab layers are welded to form a second welded portion, where the first number is less than the second number. This segmentation allows optimization of current distribution and reduction of resistance without requiring all tab layers to be welded, thus managing process complexity.
Solution Approach 2:
Different regions of the tab layers are treated differently through selective welding. The first welded portion and second welded portion are created with different numbers of welded tab layers, creating local variations in electrical connection quality. This local quality approach ensures that areas requiring higher current capacity have more welded tab layers, while other areas maintain simpler connections, thereby improving overall current density uniformity and reducing resistance.
2Reliability
If more tab layers are welded to the electrode draw-out portion, then resistance is reduced and current density uniformity is improved, but the risk of burning the electrode assembly increases
Solution Approach 1:
Instead of welding all tab layers to the electrode draw-out portion, the invention applies partial welding where only specific numbers of tab layers are welded in different portions. The first welded portion has fewer welded tab layers while the second welded portion has more, but neither welds all tab layers. This partial action approach reduces the cumulative thermal load and risk of burning the electrode assembly while still achieving sufficient resistance reduction and current density uniformity improvement through the selective welded portions.
3Object-affected harmful factors
If tab layers are not welded to the electrode draw-out portion, then the risk of burning the electrode assembly is reduced, but the conductive path is long and resistance is high
Solution Approach 1:
The tab layers are segmented into different welded and non-welded portions, creating a gradient structure. The first welded portion has fewer welded tab layers and the second welded portion has more welded tab layers, while remaining tab layers are not welded. This segmentation creates multiple conductive paths of varying lengths, ensuring that non-welded tab layers still have adequate electrical connection through adjacent welded portions, thereby maintaining low resistance without requiring all tab layers to be welded, which would increase burning risk.
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 effectively reduces resistance, improves current density uniformity, and enhances the overcurrent capability and charging efficiency of battery cells by shortening conductive paths and ensuring stronger connections between tab layers and the electrode draw-out portion.
Implementation Method 1
at least some of the plurality of turns of tab layers are welded to form a first welded portion; some of the plurality of turns of tab layers are welded to the electrode draw-out portion to form a second welded portion
Implementation Method 2
shorten a conductive path between the tab layers as well as a conductive path between the tab layers and the electrode draw-out portion, thereby reducing the resistance, improving the uniformity of current density
Data Source
AI summary
A battery cell, a method and system for manufacturing the battery cell, a battery, and a power consuming device are disclosed. The battery cell includes: a shell including an electrode draw-out portion; and an electrode assembly accommodated in the shell. The end of the electrode assembly facing toward the electrode draw-out portion is provided with a first tab, the first tab is wound around a winding axis of the electrode assembly and includes a plurality of turns of tab layers, and at least some of the plurality of turns of tab layers are welded to form a first welded portion. Some of the plurality of turns of tab layers are welded to the electrode draw-out portion to form a second welded portion; and among the tab layers connected to the first welded portion, at least one turn of tab layer is not welded to the electrode draw-out portion.