Laminate Battery Packaging Off-Center Venting Stress Concentration
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Solution Overview
Problem
Laminate-packaged electric storage devices face challenges in reliably discharging gas without causing electrolyte solution leakage due to uniform stress distribution and potential leakage at unspecified pressure release positions, leading to seal-tightness issues.
Innovation Solution
A laminate-packaged electric storage device design featuring a non-bonding section with a safety valve and seal section, where the opening is positioned off-center, and a non-thermally-bondable sheet is used between outer package films to concentrate stress and prevent premature seal section removal, ensuring gas discharge without electrolyte leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a weakly bonded area is created in the bonding section to function as a safety valve, then gas discharge capability is improved, but seal-tightness deteriorates due to uniform stress distribution causing premature seal removal
Solution Approach 1:
The patent applies local quality by creating a non-bonding section with a specific opening in a particular location (not at the center) of the outer package. This localized structural modification concentrates stress at the opening area during overpressure conditions, enabling targeted gas discharge while preserving the integrity of other bonding sections. The non-bonding section is formed by excluding a specific area from the bonding process, creating a controlled weakness only where needed for safety valve functionality.
Solution Approach 2:
The patent employs asymmetry by positioning the opening in the non-bonding section away from the center of the outer package. This asymmetric placement creates non-uniform stress distribution during pressure buildup, causing stress to concentrate at the opening rather than being evenly distributed across the bonding section. This prevents uniform stress from causing premature seal removal while maintaining effective gas discharge capability at the designated opening location.
2Stability of the object's composition
If the opening is positioned at the center of the non-bonding section, then stress distribution is uniform, but gas discharge reliability deteriorates due to unspecified pressure release positions
Solution Approach 1:
The patent deliberately positions the opening asymmetrically within the non-bonding section, specifically away from the center. This asymmetric positioning creates non-uniform stress distribution that concentrates stress at the opening location during pressure buildup. This concentration effect ensures that gas discharge occurs reliably at the specified opening position rather than at unspecified locations, improving gas discharge reliability while maintaining controlled stress distribution.
Data Source
AI summary
A laminate-packaged electric storage device includes an outer package, an electric storage device element, and an electrolyte solution, the outer package formed by stacking and seal-tight bonding outer package films along a bonding section formed in an outer edge area of the outer package films, the electric storage device element and the electrolyte solution being held in a receiving section formed inside the outer package. A non-bonding section surrounded by the bonding section and communicating with the receiving section is formed in the outer edge area, an opening is formed through at least one outer package film, and a seal section is formed to surround the opening formed in an area of the non-bonding section, the outer package films bonded in the seal section, and the opening formed in the area of the non-bonding section at a position other than a center position.