Holed Electrode Laminate Wrapping for Impact-Resistant Battery Assemblies
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Solution Overview
Problem
Irregularly-shaped lithium secondary batteries are vulnerable to external impacts due to concentrated stress at bent points, increasing the risk of damage compared to conventional symmetrical structures.
Innovation Solution
A method involving the formation of electrodes and separators into shapes with holes, laminating them to create unit cells, and wrapping a folding separator with enhanced toughness around the laminate to distribute impact forces, which is bonded using heat to secure the assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an irregularly-shaped electrode assembly is manufactured to fit device mounting spaces, then adaptability to mounting spaces is improved, but vulnerability to external impact increases due to concentrated stress at bent points
Solution Approach 1:
A folding separator with enhanced toughness is introduced as a protective layer that wraps around the electrode assembly before it is subjected to external impact. This folding separator acts as a cushioning element that absorbs and distributes impact forces, preventing stress concentration at bent points of irregularly-shaped assemblies.
Solution Approach 2:
The electrode assembly is constructed with a composite structure consisting of the original separator and an additional folding separator with different material properties (enhanced toughness). This composite structure combines the functional properties of the original separator with the protective properties of the folding separator, achieving both adaptability to irregular shapes and resistance to external impact.
2Reliability
If a folding separator with enhanced toughness is added to protect against impact, then resistance to external impact is improved, but device complexity increases
Solution Approach 1:
The folding separator is designed as a flexible thin film that can be folded and wrapped around the electrode assembly. This flexible structure provides comprehensive protection against external impact without adding significant structural complexity, as it conforms to the irregular shape of the assembly and can be secured through simple bonding of surplus parts.
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 solution enhances the safety and toughness of the electrode assembly against external impacts by distributing stress and providing additional protection with a harder, heat-bonded folding separator, even when the battery has an irregular shape.
Implementation Method 1
bonding surplus parts that are portions of the folding separator, which are not closely attached to the laminate, to each other after the portion of the space forming part is removed
Data Source
Figure 1
Figure 2(i)~2(iii)
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AI summary
The present invention provides a method for manufacturing an electrode assembly, the method comprising: a step of forming each of a negative electrode, a separator, and a positive electrode so as to have a shape having a hole; a step of laminating the negative electrode, the separator, and the positive electrode so that the holes are aligned so as to manufacture a unit cell; a step of laminating at least two or more unit cells to form a laminate; a step of folding a folding separator having an area that is enough to cover an entire surface of the laminate to wrap the outside of the laminate; a step of removing a portion of a space forming part that is a portion surrounding a space formed by the holes when the folding separator is folded to be wrapped along a circumference of the laminate; and a step of bonding surplus parts that are portions of the folding separator, which are not closely attached to the laminate, to each other after the portion of the space forming part is removed so as to finish the folding separator to cover an exposed surface of the laminate.