Folded Separator Bonding in Electrode Assemblies to Prevent Shorts
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Solution Overview
Problem
The lamination & stack type electrode assembly lacks adhesive force between unit cells, leading to potential misalignment and risk of direct short-circuit between positive and negative electrodes due to external forces or heat.
Innovation Solution
A method for manufacturing an electrode assembly that includes preparing a cell stack with first and second electrodes alternately stacked with separators, and forming a bonding part by folding and bonding the protruding separators to each other, thereby enhancing adhesion and preventing short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the lamination & stack type electrode assembly is used, then high quality and fast manufacturing are achieved, but adhesive force between unit cells is insufficient leading to misalignment and short-circuit risks
Solution Approach 1:
The separator is divided into multiple regions: a first region that fits within the electrode width, and a second region that protrudes beyond the electrode width. This segmentation allows different portions of the separator to serve different functions - electrical isolation within the electrode area and mechanical bonding outside the electrode area.
Solution Approach 2:
The protruding second region of the separator acts as an intermediary bonding element between adjacent unit cells. By extending beyond the electrode edges, it provides a dedicated bonding area that mediates the connection between separate unit cells, preventing misalignment and short-circuits while maintaining the speed of lamination & stack manufacturing.
2Reliability
If separators are extended to bond unit cells, then adhesive force is improved, but width and height of the electrode assembly increase
Solution Approach 1:
The separator is designed with non-uniform dimensions: the first region has width matching the electrode for electrical isolation, while the second region extends beyond the electrode width specifically for bonding purposes. This local differentiation allows bonding functionality to be added only where needed, without uniformly increasing the overall assembly dimensions.
Solution Approach 2:
The bonding function is achieved by utilizing the width dimension beyond the electrode edges, rather than increasing the height or length dimensions. The second region of the separator protrudes in the width direction, allowing unit cells to be bonded laterally without significantly increasing the vertical height of the assembly.
3Reliability
If the separator protrudes beyond electrodes for bonding, then short-circuit prevention is improved, but manufacturing complexity increases
Solution Approach 1:
The separator is segmented into functional regions: a first region for electrical isolation and a second protruding region for bonding. This segmentation is achieved through a single cutting step that creates the width difference, allowing complex functionality to be obtained from a relatively simple manufacturing process.
Solution Approach 2:
The separator's width parameter is changed along its length - narrower in the first region (matching electrode width) and wider in the second region (protruding beyond electrodes). This parameter variation is implemented through controlled cutting and bonding processes, enabling short-circuit prevention without requiring multiple separate components.
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
The proposed solution effectively prevents short-circuits between electrodes, allows for easy bonding of separators, and enhances energy density by minimizing unnecessary width and height increases in the electrode assembly.
Implementation Method 1
the plurality of separators may pass between a first roll and a second roll, of which at least one is heated, and be bonded to each other
Data Source
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AI summary
A method for manufacturing an electrode assembly according to an embodiment of the present invention includes: preparing a cell stack, in which a first electrode and a second electrode having a width greater than that of the first electrode are alternately stacked with a separator therebetween; and forming a bonding part that is folded toward the cell stack by bonding the plurality of separators protruding outward than the first electrode and the second electrode to each other.