Jelly-Roll Battery Assembly With Outer Negative Electrode Wrap
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In jelly-roll-type battery assemblies, the centrifugal force during winding causes the separator and electrodes to fold, leading to potential internal short circuits due to length differences between components.
Innovation Solution
A battery assembly design where a negative electrode with both active and non-coated portions is wound around the outermost periphery, with sealing tapes attached to prevent folding, ensuring the negative electrode non-coated portion serves as a tab and fixes the winding ends of the electrodes and separators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the separator is wound on the outermost periphery to ensure proper layering, then the battery assembly structure is improved, but the separator and electrodes fold due to centrifugal force
Solution Approach 1:
The patent applies local quality by creating a non-coated portion of the negative electrode at the specific location of the outermost periphery. This localized modification allows the negative electrode to extend beyond the separator, providing additional length to prevent folding at the critical winding end region without affecting the overall battery structure or other components.
Solution Approach 2:
The negative electrode is segmented into two distinct portions: a coated portion with active material and a non-coated portion without active material. This segmentation allows the non-coated portion to serve a different function (structural support and preventing fold) while the coated portion maintains its electrochemical function, thus resolving the contradiction between structural stability and manufacturing precision.
2Reliability
If the separator length is extended to cover the entire winding, then folding is prevented, but the battery assembly complexity increases
Solution Approach 1:
The non-coated portion of the negative electrode serves multiple functions: it prevents folding of the separator and electrodes, provides structural support at the winding periphery, and eliminates the need for separate extension components. This multi-functionality achieves reliable prevention of internal short circuits without increasing battery assembly complexity.
Solution Approach 2:
The negative electrode itself provides the solution to its own folding problem by incorporating a non-coated portion that extends beyond the separator. This self-service approach prevents internal short circuits using the electrode's own structure rather than requiring additional external components, thus maintaining simplicity while ensuring reliability.
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
Prevents the folding of short-length electrodes and separators, thereby preventing internal short circuits and ensuring proper contact between electrodes.
Implementation Method 1
the positive electrode, the negative electrode, and the separator positioned between the positive and negative electrodes are folded by a centrifugal force applied to wind the separator positioned on the outermost periphery
Data Source
AI summary
A battery assembly includes a negative electrode, a first separator, a positive electrode, and a second separator that are stacked and wound. The negative electrode included in the battery assembly includes a negative electrode active material portion where a negative electrode active material is located on one surface of a negative electrode current collector, and a negative electrode non-coated portion where no negative electrode active material is located on the one surface of the negative electrode current collector. The negative electrode non-coated portion is wound around an outermost periphery of the battery assembly.