Battery Tab Sealing Piece Geometry to Limit Pouch Cell Warping
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Solution Overview
Problem
The conventional rectangular sealing piece in electrochemical apparatuses deforms outward during hot pressing, leading to warping and increased exposure, which interferes with battery assembly, affects energy density, and increases electrolyte leakage risk.
Innovation Solution
The sealing piece is designed with specific section configurations, including a first section and obliquely connected second and third sections, limiting height differences and maintaining a stable shape to reduce warping and exposure, thereby enhancing energy density and sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional rectangular sealing piece is used during hot pressing, then effective sealing between tab and packaging bag is ensured, but the sealing piece deforms outward and warps, increasing exposed length and affecting energy density
Solution Approach 1:
The sealing piece is divided into multiple sections: a first section (bottom edge inside packaging bag), a second section (middle part with controlled height), and a third section (top edge outside packaging bag). This segmentation allows different parts to serve different functions - the first section provides sealing, while the second and third sections are designed with controlled dimensions to prevent warping and reduce exposed length, directly resolving the contradiction between sealing effectiveness and shape stability
Solution Approach 2:
The patent specifies precise parameter ranges for the sealing piece sections: the height H of the second and third sections is controlled at 0.05-0.5mm, and the length A of the first section is controlled at 0.5-5mm. By changing and controlling these dimensional parameters, the sealing piece maintains stability during hot pressing while ensuring effective sealing, resolving the contradiction between reliability and shape
2Shape
If the bending position of the tab is set back to prevent warping exposure, then the warping part is covered, but the overall length of the electrochemical apparatus increases, affecting energy density
Solution Approach 1:
The sealing piece is pre-designed with the second and third sections having controlled height H (0.05-0.5mm) before hot pressing. This preliminary design ensures that even after hot pressing deformation, the top edge will not warp excessively. Consequently, the tab bending position can be optimized without needing to set it back excessively, thus controlling the overall length while preventing warping exposure
3Loss of energy
If the sealing piece is reduced in size to increase energy density, then length and thickness are reduced, but sealing integrity and leakage prevention must be maintained
Solution Approach 1:
Different sections of the sealing piece are designed with different dimensional characteristics tailored to their specific functions. The first section has length A (0.5-5mm) optimized for sealing contact, while the second and third sections have controlled height H (0.05-0.5mm) to minimize exposed length. This local quality differentiation allows the sealing piece to be compact overall while maintaining sufficient sealing integrity, thus increasing energy density without compromising reliability
Solution Approach 2:
By segmenting the sealing piece into functional sections with different dimensional optimizations, the design achieves compact size for energy density while ensuring each section performs its specific function effectively - the first section ensures sealing, while the controlled second and third sections prevent warping and reduce exposure
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 effectively reduces the exposed length and thickness of the sealing piece, minimizing interference and electrolyte leakage, while maintaining sealing integrity and increasing energy density.
Implementation Method 1
during the hot pressing and sealing process of the conventional rectangular sealing piece, due to the double effects of high temperature softening and compression
Implementation Method 2
due to the double effects of high temperature softening and compression
Data Source
AI summary
The electrochemical apparatus includes a battery cell, a packaging bag, and a sealing piece. The battery cell is disposed in the packaging bag, and a tab of the battery cell protrudes from a sealing edge of the packaging bag. The sealing piece is disposed on both side of the tab, a top edge of the sealing piece is located outside the packaging bag, and a bottom edge is located inside the packaging bag. The top edge includes a first section, and a second section and a third section located at two ends of the first section. A length of the first section is A, a length of the bottom edge is B, and a width of the tab is C, meeting B>A≥C. A height of the second section or the third section is H, meeting 0.05 mm≤H≤0.5 mm.