Pouch Battery Jelly Roll Tape Layout for Better Cell Flatness
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Solution Overview
Problem
The surface unevenness of the jelly roll in lithium-ion batteries leads to poor flatness, affecting interface adhesion and resulting in reduced cycle life and deformation issues.
Innovation Solution
A jelly roll design where the inner surface of the negative electrode plate's bending region is covered by a first tape layer, with projections of the tape layer connected to the winding head to equalize thickness, and additional tape layers are used to prevent burrs and enhance uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the jelly roll is wound without additional tape layers, then the manufacturing process is simple, but the surface unevenness is serious and flatness is poor
Solution Approach 1:
The patent applies local quality by adding tape layers specifically to the bending region of the negative electrode plate where surface unevenness occurs. The first tape layer is adhered to the inner surface of the bending region, and the second tape layer is wrapped around the outer surface, providing localized compensation without modifying the entire jelly roll structure. This resolves the contradiction by improving flatness (parameter_id: 29) only where needed while maintaining simplicity elsewhere.
Solution Approach 2:
The patent implements preliminary action by pre-adhering the first tape layer to the bending region before winding, and pre-wrapping the second tape layer around the outer surface. These preparatory actions ensure that the tape layers are in position to compensate for surface unevenness before the winding process completes, thereby improving flatness (parameter_id: 29) without adding complex post-processing steps.
2Reliability
If the bending region is left without tape coverage, then the manufacturing process is simple, but interface adhesion is poor and cycle life is reduced
Solution Approach 1:
The patent applies local quality by targeting the bending region specifically with tape layers. The first tape layer is adhered to the inner surface of the bending region, and the second tape layer is wrapped around the outer surface, providing localized compensation without modifying the entire jelly roll structure. This resolves the contradiction by improving flatness (parameter_id: 29) only where needed while maintaining simplicity elsewhere.
Solution Approach 2:
The patent implements preliminary action by pre-adhering the first tape layer to the bending region before winding, and pre-wrapping the second tape layer around the outer surface. These preparatory actions ensure that the tape layers are in position to compensate for surface unevenness before the winding process completes, thereby improving flatness (parameter_id: 29) without adding complex post-processing steps.
3Manufacturing precision
If additional tape layers are added to the bending region, then flatness and interface adhesion are improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by targeting the bending region specifically with tape layers. The first tape layer is adhered to the inner surface of the bending region, and the second tape layer is wrapped around the outer surface, providing localized compensation without modifying the entire jelly roll structure. This resolves the contradiction by improving flatness (parameter_id: 29) only where needed while maintaining simplicity elsewhere.
Data Source
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AI summary
The present application provides a jelly roll and a punch cell, and relates to the field of lithium battery technologies. The jelly roll includes a negative electrode plate, along a winding direction, an inner surface of a second bending region of the negative electrode plate is covered by a first tape layer, and in a thickness direction of the jelly roll, a projection of two ends of the first tape layer is connected to or partially overlapped with a projection of a winding head of the negative electrode plate. As a result, surface unevenness of the jelly roll is improved, thereby improving a flatness of a battery cell.