Cylindrical Battery Current Interrupt Mechanism Pressure Variation
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Solution Overview
Problem
The existing current interrupt mechanisms in cylindrical batteries exhibit significant variation in operating pressure, which affects the design value and mechanical strength of the terminal plate, leading to unreliable operation and safety concerns.
Innovation Solution
A cylindrical battery design featuring a current interrupt mechanism with a metal plate and insulating plate configuration, where the metal plate includes a thin portion with a circular or C-shape, concentric with the hollow portion, and a ratio of D1/D2 between 0.56 and 1, reducing the variation in operating pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thin portion of the metal plate is made thinner to reduce operating pressure variation, then the mechanical strength of the terminal plate decreases, but the operating pressure variation is reduced
Solution Approach 1:
The metal plate is designed with a thin portion that has a different thickness than other parts of the plate. This local variation in quality allows the thin portion to break at a specific pressure while the rest of the plate maintains sufficient mechanical strength. The thin portion's reduced thickness creates a controlled weak point that determines the operating pressure, while the thicker surrounding areas provide structural support.
2Reliability
If the design value of operating pressure is determined low to account for variation, then the current interrupt mechanism operates reliably, but the mechanical strength of the terminal plate is reduced
Solution Approach 1:
The invention changes the physical parameter of the metal plate by creating a thin portion with controlled dimensions. The ratio D1/D2 (where D1 is the diameter of the thin portion and D2 is the diameter of the hollow portion) is specifically controlled to be between 0.05 and 0.8. This parameter change allows precise control over the operating pressure while maintaining adequate mechanical strength in the overall structure.
3Strength
If the thin portion diameter D1 is increased to improve mechanical strength, then the operating pressure increases, but the operating pressure variation increases
Solution Approach 1:
The invention optimizes the parameter D1 (diameter of the thin portion) within a specific range relative to D2 (diameter of the hollow portion), with the ratio D1/D2 between 0.05 and 0.8. This parameter optimization achieves a balance where the thin portion is thick enough to maintain mechanical strength but thin enough to ensure consistent breaking pressure with minimal variation.
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
This configuration reduces the variation in operating pressure, enhancing the mechanical strength of the terminal plate and improving the reliability and safety of the battery by stabilizing the current interrupt mechanism.
Implementation Method 1
The inner aluminum foil 52 includes an annular thin portion 52a that is formed around a weld between the inner aluminum foil 52 and the outer aluminum foil 51. When the pressure in the battery reaches a certain value, the thin portion 52a breaks, and a current path between the outer and inner aluminum foils 51 and 52 is interrupted.
Implementation Method 2
When the pressure in the battery further increases, the outer aluminum foil 51 breaks, and gas in the battery is discharged. The outer aluminum foil 51 functions as a safety valve in this way.
Implementation Method 3
The insulating plate 53 includes a hollow portion in a central portion, and the outer aluminum foil 51 and the inner aluminum foil 52 are joined to each other in the hollow portion of the insulating plate 53.
Data Source
AI summary
A cylindrical battery according to an embodiment of the present invention includes an electrode body, an electrolyte solution, a tubular exterior can that accommodates the electrode body and the electrolyte solution, and a sealing body that is crimped on an opening portion of the exterior can. The sealing body includes a current interrupt mechanism in which a valve member and a metal plate are joined to each other with an insulating plate that includes a circular hollow portion interposed therebetween. The metal plate includes a thin portion that has a circular shape or a C-shape. The hollow portion and the thin portion are concentric with each other when viewed from a direction perpendicular to the metal plate. D1/D2 is no less than 0.56 and no more than 1 where D1 is the diameter of the thin portion, and D2 is the diameter of the hollow portion.