Battery Cell Tab Asymmetry for Fast-Charging Low DCR
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Solution Overview
Problem
Traditional battery charging methods are slow, leading to reduced electron transferring speed and increased direct current resistance (DCR), which limits the cycling service life and overcurrent capacity, especially during fast charging.
Innovation Solution
The design includes a cell with a positive-electrode tab that is longer than the negative-electrode tab, forming a high-speed electron channel, which reduces electron transferring resistance and DCR, and increases the weldable area for improved overcurrent capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tab length is increased to improve electron transferring speed and reduce DCR, then the welding area and overcurrent capacity are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies asymmetry by making the positive electrode tab longer than the negative electrode tab. Specifically, the positive electrode tab extends beyond the positive electrode sheet by a first length, while the negative electrode tab extends beyond the negative electrode sheet by a second length that is shorter than the first length. This asymmetric design optimizes electron transfer pathways and reduces DCR without requiring complex symmetric modifications throughout the entire cell structure.
Solution Approach 2:
The patent applies local quality by differentiating the tab extension lengths at specific locations. The positive electrode tab has a longer extension length compared to the negative electrode tab, creating localized optimization in the electron transfer path where it is most needed. This allows the cell to achieve lower DCR and improved fast charging performance without uniformly increasing the complexity of the entire cell structure.
2Productivity
If traditional charging methods are used to maintain simple charging infrastructure, then the system complexity is low, but the charging speed is slow and user experience is limited
Solution Approach 1:
The asymmetric tab design with the positive electrode tab extending further than the negative electrode tab creates optimized electron transfer channels that enable faster charging rates. This structural asymmetry reduces internal resistance and allows the cell to accept higher charging currents, directly improving productivity in terms of charging speed without requiring external charging infrastructure changes.
Solution Approach 2:
The patent changes the geometric parameters of the electrode tabs, specifically the extension lengths beyond the electrode sheets. By setting the first extension length (positive tab) greater than the second extension length (negative tab), the cell achieves optimized electrical characteristics that enable fast charging performance, transforming the cell from suitable only for traditional slow charging to capable of high-speed charging.
Data Source
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AI summary
A cell includes at least one cell core. Each of the at least one cell core includes a positive-electrode sheet, a positive-electrode tab, a negative-electrode sheet, and a negative-electrode tab; the positive-electrode tab is arranged on the positive-electrode sheet; the positive-electrode tab extends away from the positive-electrode sheet; a length of the positive-electrode tab in a direction perpendicular to an extension direction of the positive-electrode tab is L1; the negative-electrode tab is arranged on the negative-electrode sheet; the negative-electrode tab extends away from the negative-electrode sheet, a length of the negative-electrode tab in a direction perpendicular to an extension direction of the negative-electrode tab is L2, where L1/L2=n, and the n is in a range of 1.2≤n≤2.