Pouch Cell Seal Edge Geometry for Higher Energy Density
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Solution Overview
Problem
Special-shaped batteries with rectangular edges occupy excessive space, reducing their energy density.
Innovation Solution
Designing the seal edges of the packaging bag as arc sections to minimize space occupation and increase energy density, with specific configurations such as arc-shaped first and second hems that reduce width and prevent wrinkling when bent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rectangular seal edges are used for special-shaped batteries, then the sealing structure is simple and easy to manufacture, but the space occupied by the seal edges increases, reducing energy density
Solution Approach 1:
The patent applies curvature by designing the seal edges with arc sections instead of straight rectangular lines. Specifically, the first seal edge includes a first arc section, and the second seal edge includes a second arc section, allowing the battery to fit more efficiently into the packaging bag and reduce wasted space, thereby improving energy density while maintaining manufacturability
2Quantity of substance
If arc-shaped seal edges are designed to reduce space occupation, then energy density increases, but the seal edge structure becomes more complex
Solution Approach 1:
The patent segments the seal edges into distinct functional parts: straight sections for simple sealing and arc sections for space optimization. The first seal edge is divided into a first straight section and a first arc section, while the second seal edge is divided into a second straight section and a second arc section. This segmentation allows each part to serve its specific function while keeping the overall structure manageable
3Reliability
If the second hem is designed as a two-layer structure with stacked parts, then the probability of wrinkling and seal breakage during bending is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent implements beforehand cushioning by designing the second hem as a two-layer structure where a first part and a second part are stacked. The second part is positioned between the first part and the second section, creating a buffer layer that prevents wrinkling and seal breakage during bending operations. This preventive design addresses potential failure modes before they occur
Data Source
AI summary
An electrochemical device includes an electrode assembly, a packaging bag accommodating the electrode assembly, and electrode terminals connected to the electrode assembly. The packaging bag includes a first seal edge, a third seal edge, a first sidewall connected to the first seal edge, a second sidewall connected to the third seal edge, and a third sidewall. The first sidewall includes a first section connected to the second sidewall; and an arc-shaped second section connected to the third sidewall and the first section. The first seal edge includes a first hem connected to the first section and a second hem connected to the first hem. The first hem is disposed along the thickness direction of the electrode assembly. The second hem includes a first part and a second part. The second part is connected to the second section and the first part and abuts against the second section.