Cylindrical Battery Lead Layout for Lower Internal Resistance
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Solution Overview
Problem
Conventional cylindrical batteries with one lead per electrode face challenges in reducing internal resistance.
Innovation Solution
A cylindrical battery design with a single positive electrode lead connected between the winding start and terminal sides of the positive electrode mixture layer, and a single negative electrode lead connected between specific positions on the negative electrode, ensuring optimal contact with the outer can, thereby reducing internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If only one lead is provided in each electrode, then the roundness of the electrode assembly is enhanced and good battery characteristics are obtained, but internal resistance cannot be reduced
Solution Approach 1:
The positive electrode lead is divided into two connection points: one connected to the winding start side end of the positive electrode mixture layer and another to the winding terminal side end. This segmentation allows current to be collected from both ends of the electrode assembly, reducing internal resistance while maintaining the single-lead configuration that ensures good roundness.
Solution Approach 2:
The negative electrode lead is positioned at a specific location (third position) that is offset from the axial ends, creating a three-dimensional current collection path. This spatial arrangement optimizes current distribution and reduces internal resistance without compromising the electrode assembly's roundness.
2Device complexity
If the positive electrode lead is connected at the axial end portion, then the structure is simple, but the current collecting path is long and internal resistance increases
Solution Approach 1:
Instead of a single axial connection, the positive electrode lead is segmented to connect at both the winding start side end and winding terminal side end of the positive electrode mixture layer. This creates multiple current collection paths, shortening the effective current path length and reducing internal resistance while keeping the structural complexity manageable.
3Ease of manufacture
If the negative electrode lead is positioned at the axial end, then manufacturing is easy, but current collection efficiency is poor
Solution Approach 1:
The negative electrode lead is positioned at a specific local region (third position) on the negative electrode that is optimized for current collection. This position is determined based on the relative positioning with the positive electrode lead and the winding structure, creating a locally optimized current collection zone that improves overall efficiency.
Data Source
AI summary
An anode lead is bonded between a winding start side end of an anode mixture layer and a winding finish side end of the anode mixture layer in an a direction of an electrode. When a position opposite to an anode start end is defined as a first position and the center position of a portion opposite to the anode lead is defined as a second position in a cathode mixture layer in a γ direction of a cathode, a cathode lead is bonded between the first position and the second position with respect to the γ direction of the cathode. A cathode core is made to contact the inner peripheral surface of the outer casing.