Battery Unit Cell Sealing Member Edge Bending
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Solution Overview
Problem
Conventional unit cells with exposed metal layers are prone to electrical leakage due to condensation, as water droplets can adhere to the metal layer, causing short circuits, especially when the size is minimized by folding and overlapping the sealing members.
Innovation Solution
A unit cell design featuring a flat cell body with a sheet-shaped metal and insulating layer, where the metal layer is spaced from the insulating layer, and the outer edges of the sealing member are bent to prevent water from reaching the exposed metal, with spacers housing the metal layer to prevent contact and enhance size reduction while maintaining insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the outer edges of the sealing member are folded and overlapped to reduce size, then the unit cell size is reduced, but water droplets can adhere to the exposed metal layer causing electrical leakage
Solution Approach 1:
The sealing member's metal layer is bent in the longitudinal direction to create a three-dimensional configuration. This bending moves the exposed end portion of the metal layer away from the surface where condensation occurs, effectively using spatial dimensionality to prevent water contact while maintaining the compact folded structure
Solution Approach 2:
The bent configuration of the metal layer acts as an intermediary barrier between the exposed metal surface and water droplets. By positioning the exposed end portion away from the condensation-prone surface through bending, the structure creates a protective spatial arrangement that prevents direct contact between water and the conductive metal layer
2Reliability
If the exposed end portion of the metal layer is spaced from the insulating layer surface, then electrical leakage is prevented, but the sealing member structure becomes more complex
Solution Approach 1:
The sealing member structure is segmented into distinct functional zones: the insulating layer covering most of the metal layer, and the exposed end portion that is bent away. This segmentation allows the metal layer to serve dual purposes - electrical conductivity where covered and spatial positioning where exposed - without requiring additional insulating components
Solution Approach 2:
The metal layer itself performs the protective function by being bent into a configuration that naturally positions its exposed end away from the condensation surface. This self-positioning mechanism eliminates the need for separate protective structures or complex assembly steps, achieving reliability through the metal layer's own geometric configuration
Data Source
AI summary
A unit cell including a cell body, an electrode tab (an anode side electrode tab and a cathode side electrode tab) and a sealing member (laminate film). The cell body includes a power-generating element and is formed into a flat shape. The anode side electrode tab and the cathode side electrode tab extend out from the cell body. The sealing member (laminate film) includes a sheet-shaped metal layer and a sheet-shaped insulating layer that covers and insulates the metal layer from both sides to sandwich and seal the cell body. In the sealing member, an exposed end portion of a metal layer is spaced from a surface of the insulating layer, while bending at least a portion of an outer edge.