Battery Pouch Frame Unit for High-Capacity Electrode Assembly
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Solution Overview
Problem
The existing pouch-type lithium secondary batteries face challenges in maintaining stability and reliability as the thickness of the electrode assembly increases, leading to potential cracks in the sheets and exposure of metal parts, which reduces the battery's lifetime and capacity.
Innovation Solution
A pouch design incorporating a frame unit sealed by two sheets, with a sealant layer and tab frames to accommodate large electrode assemblies, enhancing stiffness and capacity while preventing cracks and ensuring secure sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the electrode assembly is increased to achieve high capacity, then the battery capacity is improved, but the sheets may crack and metal parts may be exposed, reducing reliability
Solution Approach 1:
The pouch is divided into a frame unit and a sealed unit. The frame unit includes first and second sheets with accommodating spaces that support the electrode assembly, while the sealed unit provides sealing. This segmentation allows the sheets to maintain structural integrity through proper support while accommodating thick electrode assemblies for high capacity.
Solution Approach 2:
A sealing piece is introduced as an intermediary component between the first and second sheets. The sealing piece includes a sealing surface that contacts both sheets and provides reliable sealing through adhesive bonding, preventing metal part exposure and maintaining sheet integrity in high-capacity batteries.
2Strength
If a traditional sealed pouch structure is used, then the manufacturing process is simple, but the pouch lacks sufficient stiffness to maintain stability with large electrode assemblies
Solution Approach 1:
The pouch is segmented into a frame unit providing stiffness and a sealed unit providing sealing. The frame unit includes first and second sheets with accommodating spaces that give the pouch structural rigidity, while the separate sealed unit maintains manufacturing simplicity through modular assembly.
Solution Approach 2:
Different parts of the pouch have different functions: the frame unit (first and second sheets) provides stiffness and structural support, while the sealed unit provides sealing. This local differentiation of quality allows the pouch to achieve high stiffness without significantly increasing overall complexity.
3Reliability
If the sheets are closely attached to seal the pouch, then sealing is achieved, but cracks may occur and metal parts may be exposed, reducing lifetime
Solution Approach 1:
A sealing piece acts as an intermediary between the first and second sheets, providing reliable sealing through adhesive bonding. The sealing piece includes a sealing surface that contacts both sheets, ensuring secure attachment without causing cracks or metal part exposure, thereby maintaining sealing integrity and extending battery lifetime.
Solution Approach 2:
The sealing piece includes a sealing surface that self-adheres to the first and second sheets through adhesive bonding, creating a reliable seal without requiring additional complex sealing mechanisms. This self-service sealing approach maintains sealing integrity and prevents defects that would reduce battery lifetime.
Data Source
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AI summary
Provided are a pouch for a secondary battery including a first sheet and a second sheet, and a frame unit which is sealed by the first sheet and the second sheet and includes an accommodating part for accommodating an electrode assembly including electrode tabs therein, and a secondary battery including the pouch. According to the present invention, since a structure of a pouch for a secondary battery may include a frame unit capable of accommodating a large electrode assembly, a high-capacity and large-area secondary battery having high capacity and high stiffness may be realized.