Cylindrical Battery Sealing Geometry for High-Temperature Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonaqueous electrolyte secondary batteries face challenges in maintaining sealing properties and preventing electrolyte volatilization and moisture intrusion under high-temperature environments, as simply increasing the compression ratio of the gasket can lead to gasket fracture and deteriorated sealing.
Innovation Solution
Defining the position of the caulking tip end, shape, and dimensions of the positive electrode casing, along with the size relationship between the battery and the casing, to achieve an appropriate compression ratio of the gasket, using materials like polypropylene resin or polyether ether ketone for the gasket, and optimizing the electrolyte composition with propylene carbonate, ethylene carbonate, and dimethoxy ethane, to ensure effective sealing and discharging capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compression ratio of the gasket is increased to improve sealing properties under high-temperature environment, then sealing properties are improved, but the gasket may fracture and sealing deteriorates
Solution Approach 1:
The patent applies parameter changes by specifying precise dimensional parameters for the positive electrode casing (outer diameter d=4mm to 12mm, height h1=1mm to 3mm, height of side surface portion h2=78.3% to 87.1% of h1, radius of curvature R=0.8mm to 1.1mm) and the gasket (thickness t1=0.1mm to 0.3mm, compression ratio 50% to 95%). These parameter optimizations ensure the gasket achieves sufficient compression for sealing while maintaining structural integrity and preventing fracture under high-temperature conditions.
2Reliability
If the compression ratio of the gasket is increased to prevent electrolyte volatilization and moisture intrusion, then sealing properties are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes manufacturing precision by defining specific parameter ranges for the positive electrode casing dimensions (outer diameter d, height h1, side surface height h2, radius of curvature R) and gasket thickness t1. These standardized parameters enable precise manufacturing and assembly, ensuring consistent compression ratios and reliable sealing without requiring excessive manufacturing precision.
3Reliability
If the radius of curvature of the side surface portion is increased to improve sealing, then sealing properties are improved, but the height of the positive electrode casing must be increased
Solution Approach 1:
The patent resolves this contradiction by optimizing the radius of curvature R to specific values (0.8mm to 1.1mm) and setting the side surface height h2 to 78.3% to 87.1% of the total height h1. This parameter optimization achieves effective sealing through the curved surface geometry without requiring a proportional increase in the overall height of the positive electrode casing, maintaining compact battery dimensions.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a nonaqueous electrolyte secondary battery including a bottomed cylindrical positive electrode casing, and a negative electrode casing which is fixed to an opening of the positive electrode casing through a gasket. The opening of the positive electrode casing is caulked to the negative electrode casing side to seal an accommodation space. A caulking tip end in the opening of the positive electrode casing is disposed in an inward direction of the negative electrode casing than a tip end of the negative electrode casing. A diameter d of the nonaqueous electrolyte secondary battery is in a range of 4 mm to 12 mm, a height h1 of the nonaqueous electrolyte secondary battery is in a range of 1 mm to 3 mm, a side surface portion of the positive electrode casing is formed in a curved surface shape, a radius of curvature R is set in a range of 0.8 mm to 1.1 mm, and a height h2 of the positive electrode casing is in a range of 65% to 90% with respect to the height h1 of the nonaqueous electrolyte secondary battery.