Pouch Cell Folded Corner Sealing for Higher Energy Density
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Solution Overview
Problem
Existing electrochemical apparatuses face challenges in maximizing energy density due to the space occupied by sealing edges and the risk of electrolyte leakage, particularly when subjected to mechanical abuse.
Innovation Solution
The electrochemical apparatus incorporates a folded corner structure formed by folding the transition zone at least twice, reducing the size of the sealing portion and minimizing the space occupied, which enhances energy density and reduces the risk of leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing portion is added to package the electrode assembly, then reliability is improved, but volume increases
Solution Approach 1:
The transition zone is folded into the body portion of the packaging bag, creating a nested structure where the sealing portion is integrated within the existing volume rather than adding external bulk. This allows the sealing function to be incorporated without proportionally increasing the overall volume of the packaging bag.
Solution Approach 2:
The transition zone is folded along the thickness direction (second direction) of the electrode assembly, utilizing the Z-dimension to create the sealing structure. This dimensional approach allows the sealing portion to be formed within the existing footprint rather than extending the volume in the planar directions.
2Reliability
If the transition zone is made larger to ensure sealing integrity, then reliability is improved, but energy density decreases
Solution Approach 1:
The transition zone is folded into the body portion, nesting the sealing structure within the existing volume. This ensures adequate sealing integrity is achieved while minimizing the volume occupied by the sealing portion, thereby maximizing the volume available for active materials and improving energy density.
Solution Approach 2:
The transition zone utilizes the flexibility of the packaging film to create multiple folds within a compact space. This allows the sealing structure to achieve sufficient length and complexity for reliable sealing while occupying minimal volume that would otherwise be available for energy-storing materials.
3Volume of stationary object
If the transition zone is folded multiple times to reduce size, then volume decreases, but structural integrity may worsen
Solution Approach 1:
The transition zone is folded into the body portion in a controlled manner, creating a nested structure that reduces volume while maintaining strength. The folding is designed so that the folded layers support each other, distributing mechanical stresses and preventing weak points that would arise from simple compression.
Solution Approach 2:
The packaging film is designed with composite structure and appropriate material properties to withstand the multiple folding operations. The material composition and layer structure are selected to provide sufficient flexibility for folding while maintaining mechanical strength and preventing rupture during mechanical abuse.
4Ease of manufacture
If a standard rectangular shape is used for the packaging bag, then ease of manufacture is improved, but adaptability decreases
Solution Approach 1:
The folding of the transition zone creates an asymmetric configuration that allows the packaging bag to adapt to non-standard battery compartment shapes. This asymmetric folding pattern enables the battery to be positioned optimally within the compartment while maintaining effective sealing, thereby improving adaptability without requiring completely custom packaging designs.
Data Source
AI summary
An electrochemical apparatus includes a packaging bag including a body portion and a sealing portion, an electrode assembly disposed in the body portion, and a conductive plate electrically connected to the electrode assembly. The body portion includes a first end wall and a second end wall disposed opposite to each other in a first direction, and further includes a first side wall and a second side wall disposed opposite to each other in a third direction. The sealing portion includes a first sealing portion and a first folded edge portion disposed opposite to the first side wall in the third direction. The conductive plate protrudes out of the packaging bag from the first sealing portion. The first sealing portion and the first folded edge portion intersect in a transition zone. The transition zone is folded towards the first end wall at least twice to form a folded corner structure.