Cylindrical Battery Case with Bent Opening End for Miniaturization
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Solution Overview
Problem
Miniaturization of cylindrical batteries poses challenges in reducing the outer diameter of the battery case while maintaining both safety against internal pressure and sealability to prevent electrolyte leakage, as conventional pressure reducing mechanisms are difficult to implement effectively in small sizes.
Innovation Solution
A cylindrical battery design with a bent or curved opening end and an annular constriction, where the gasket compresses the sealing member, allowing for a deviation range of -0.1 mm to +0.5 mm between the sealing member rim and the opening end, along with specific compressibility and orientation conditions, to ensure safe pressure relief and seal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the outer diameter of the battery case is decreased to downsize the cylindrical battery, then the miniaturization requirement is satisfied, but it becomes difficult to attach a pressure reducing mechanism to the sealing member and make it exhibit sufficient pressure reducing capability
Solution Approach 1:
The pressure reducing mechanism is extracted from the sealing member and integrated into the battery case structure itself. The opening end of the battery case is bent or curved toward the center axis to form an annular constriction that acts as the pressure reducing mechanism, eliminating the need for separate pressure reducing components on the sealing member.
Solution Approach 2:
The sealing function and pressure reducing function are merged into a single integrated structure. The bent opening end of the battery case simultaneously provides sealing support through the gasket and pressure reducing capability through the annular constriction, combining multiple functions in one component.
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 design achieves both safety by preventing battery case breakage and sealability by preventing electrolyte leakage, even under increased internal pressure, while maintaining a small size, with a vent pressure range of 4 MPa to 25 MPa and high sealability through controlled gasket compressibility.
Implementation Method 1
an annular gasket interposed between the opening of the battery case and the sealing member. The gasket is compressed by the opening end and the constriction, and the rim portion of the sealing member is grasped by the compressed gasket.
Data Source
AI summary
In a cylindrical battery, a bottomed cylindrical battery case includes an opening end bent or curved toward a center axis of the battery case, and a constriction annularly formed around the center axis. A gasket is compressed by the opening end and the constriction, and a rim portion of the sealing member is grasped by the compressed gasket. The outer diameter of the battery case is 10 mm or less. A first corresponding line corresponds to the rim of the sealing member in a projected image of the sealing member on the virtual plane perpendicular to the center axis of the battery case, and a second corresponding line corresponds to a tip edge of the opening end in a projected image. In this case, deviation d of the second corresponding line from the first corresponding line toward the center axis satisfies −0.1 mm≤d≤+0.5 mm.