Battery Cell Insulating Sheet Fold Geometry for Shrink Control
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Solution Overview
Problem
The insulating film covering the exterior container of a battery cell can deform into unintended shapes, potentially interfering with other components in the battery module, such as protruding onto the upper surface and causing issues with the separator function and electrode terminal connections.
Innovation Solution
The insulating sheet is designed with a folded portion that includes a peak portion and valley portions, allowing it to be thermally shrunk without laying over the upper surface, thereby preventing excessive deformation and interference with surrounding components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating film is brought into close contact with the exterior container through thermal shrinkage, then the insulating film covers the outer surface effectively, but the insulating film may deform and protrude onto the upper surface, interfering with other components
Solution Approach 1:
The insulating sheet is pre-formed with a folded portion structure before thermal shrinkage. This preliminary shaping ensures that during the shrinking process, the material follows a predetermined path that prevents unwanted protrusion onto the upper surface, while still achieving complete coverage of the exterior container's outer surface.
Solution Approach 2:
The insulating sheet is divided into distinct functional zones: a folded portion that follows the side surface contour, a peak portion that reaches the upper surface, and valley portions that create controlled recesses. This segmentation allows different regions to serve specific purposes - the folded portion provides coverage, the peak portion maintains contact, and the valley portions prevent excessive protrusion that could interfere with battery module components.
2Reliability
If the insulating film is made to cover the entire outer surface, then insulation is improved, but the film complexity and difficulty of controlling its shape increase
Solution Approach 1:
The folded portion structure is pre-formed in the insulating sheet before assembly. This preliminary action defines the three-dimensional configuration that the film will assume during thermal shrinkage, making the shaping process predictable and controllable while ensuring complete surface coverage.
Solution Approach 2:
The insulating sheet utilizes the flexibility and conformability of thin film materials to achieve complex three-dimensional coverage of the exterior container. The folded portion with its peak and valley structures allows the thin film to adapt to the container's geometry while maintaining insulation effectiveness and preventing interference with surrounding components.
3Reliability
If the insulating sheet is thermally shrunk to fit tightly, then the insulating effect is improved, but the sheet may deform into unintended shapes
Solution Approach 1:
The folded portion structure is pre-formed in the insulating sheet before thermal shrinkage. This preliminary configuration acts as a shape guide that directs the thermal shrinkage process, ensuring the film tightens uniformly without deforming into unintended shapes while still achieving the necessary insulating effect.
Solution Approach 2:
The thermal shrinkage process utilizes controlled parameter changes (temperature, time, and shrinkage ratio) to achieve tight fitting of the insulating sheet. By carefully controlling these parameters, the sheet achieves maximum insulation effectiveness while the pre-formed folded portion structure prevents unwanted deformation, maintaining manufacturing precision.
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
This design suppresses unnecessary protrusion of the insulating film, maintaining the integrity of the separator function and ensuring reliable electrode terminal connections by controlling the thermal shrinkage process, thus preventing interference with other module components.
Implementation Method 1
The insulating sheet is in a form of a film and that is provided on the outer surface of the exterior container... in a step of bringing the insulating film into close contact with the exterior container
Data Source
AI summary
A battery cell includes: an electrode assembly; an exterior container; two electrode terminals provided on an upper surface of the exterior container and arranged side by side in a first direction; and an insulating sheet that is in a form of a film and that is provided on the outer surface of the exterior container. The insulating sheet has a folded portion that reaches the upper surface from a short side surface of the exterior container. The folded portion includes a peak portion and valley portions, the peak portion protruding from the short side surface side to the two electrode terminals side along the first direction, the valley portions being located on both sides with respect to the peak portion in a second direction orthogonal to the first direction, each of the valley portions being recessed toward a side away from the two electrode terminals.