Segmented Tape for Battery Electrode Group Fixation
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries face the challenge of electrode plate deformation during charge-and-discharge cycles, which can lead to internal short circuits due to pressure from the battery case, and existing solutions do not adequately suppress this deformation or maintain long-term adhesive functionality of the tapes.
Innovation Solution
A non-aqueous electrolyte secondary battery design featuring a bottomed cylindrical case with a wound-type electrode group, where a current collector of the negative electrode plate is exposed and contacts the case body, and tapes with a base material layer and adhesive layer are attached to the outermost peripheral surface, with the adhesive layer continuously disposed in the winding direction to prevent excessive pressure and maintain adhesion over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the electrode group is tightly fixed by attaching a tape to the outermost peripheral surface, then the electrode group is securely held in the battery case, but the pressure from the battery case acts excessively on the electrode group during expansion, causing electrode plate deformation
Solution Approach 1:
The tape's adhesive layer is divided into multiple regions (first regions with base material only, and second regions with base material and adhesive) arranged alternately in the winding direction. This segmentation allows the tape to provide fixation while reducing excessive pressure concentration on the electrode group during expansion, preventing electrode plate deformation.
Solution Approach 2:
Different regions of the tape have different adhesive properties: the first regions have no adhesive layer to reduce pressure, while the second regions have adhesive layers to provide fixation. This local quality variation allows the tape to simultaneously achieve secure fixation and prevent excessive pressure-induced deformation.
2Strength
If the adhesive layer is disposed continuously in the winding direction to ensure strong adhesion, then the tape firmly holds the electrode group, but the non-aqueous electrolyte can enter the adhesive layer, degrading the adhesive function over time
Solution Approach 1:
The adhesive layer is segmented into discrete second regions separated by first regions without adhesive. This segmentation prevents continuous electrolyte penetration along the winding direction, as the first regions act as barriers, thereby maintaining adhesive strength over long periods.
Solution Approach 2:
The first regions (base material without adhesive) serve as intermediary barriers that block the path of non-aqueous electrolyte from reaching and degrading the adhesive layers in the second regions, thus preserving long-term adhesive functionality.
3Temperature
If the current collector is exposed and contacts the battery case to improve heat dissipation, then heat dissipation capability is improved, but the electrode group expansion during charging causes stress concentration at the contact point
Solution Approach 1:
The tape structure incorporates local quality variations with adhesive-free first regions that reduce stress concentration, allowing the current collector to maintain contact with the battery case for heat dissipation while preventing excessive stress buildup at specific contact points during electrode expansion.
Data Source
AI summary
This nonaqueous electrolyte secondary battery includes a winding-type electrode group which comprises a positive electrode plate and a negative electrode plate, and tape adhered on the peripheral surface of the electrode group. A current collector of the negative electrode plate is exposed in at least part of the outermost peripheral surface of the electrode group in the winding direction, and the current collector contacts a case body. The tape comprises a base material layer and an adhesive layer arranged continuously in the winding direction on the inner surface of the wound base material layer. Dividing the region seen from the wound inner surface of the tape into first regions configured from the base material layer and second regions configured from the base material layer and the adhesive layer, the first regions are interposed between second regions in at least part of the area of the tape in the winding direction.