Cylindrical Battery Washer Geometry for Stable Cut-Off Pressure
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Solution Overview
Problem
The variation in operating pressure of the current cut-off mechanism in cylindrical batteries is increased due to differences in the inner diameter of the metal washer when the front and back sides are used randomly, leading to inconsistent performance and manufacturing complexities.
Innovation Solution
A washer with a recessed section formed around its central opening and planar sections on either side, where the boundary lines between these sections are arranged to overlap in the thickness direction, ensuring consistent contact with the valve disc and reducing pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal washer is disposed between the terminal cap and the valve disc, then electrical connection is ensured, but the inner diameter of the contact part varies depending on which side (front or back) is used, causing variation in operating pressure
Solution Approach 1:
The washer is designed with asymmetric structure where the inner circumferential surface has a first contact portion with a first inner diameter on one side and a second contact portion with a second inner diameter on the other side. This asymmetric design allows the current cut-off mechanism to operate at a predetermined pressure when the first side contacts the valve disc, while preventing operation when the second side contacts, thereby ensuring consistent operating pressure without requiring complex manufacturing processes to control washer orientation
Solution Approach 2:
The washer is designed in advance with the asymmetric contact portions and different inner diameters built into its structure. This preliminary design ensures that regardless of which side of the washer faces the valve disc during assembly, the current cut-off mechanism will operate at the correct predetermined pressure, eliminating the need for post-assembly adjustments or complex orientation control procedures
2Manufacturing precision
If the orientation of the metal washer is aligned during production, then operating pressure variation is reduced, but the manufacturing process becomes complicated and costs increase
Solution Approach 1:
The washer incorporates asymmetric contact portions with different inner diameters on opposite sides, which inherently ensures correct operating pressure without requiring precise orientation control during manufacturing. The asymmetric design makes the mechanism pressure-sensitive only in the correct orientation, eliminating the need for complex alignment procedures
Solution Approach 2:
The asymmetric washer design allows the current cut-off mechanism to self-regulate its operation based on which side of the washer contacts the valve disc. The mechanism automatically operates at the predetermined pressure when the correct side contacts, without requiring external intervention or complex manufacturing controls to ensure proper orientation
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 design reduces the variation in operating pressure of the current cut-off mechanism, maintaining consistent performance without increasing manufacturing complexity or costs.
Implementation Method 1
a washer (22) having an opening (22a) at a center, interposed between the terminal cap (21) and the valve disc (23), the washer (22) has a recessed section (22c) formed in surroundings of the opening (22a) and a planar section (22b) disposed in surroundings of the recessed section (22c) on each of surfaces at both ends in a thickness direction of the washer (22)
Data Source
AI summary
A cylindrical battery including an electrode body in which a positive electrode plate and a negative electrode plate with a separator between the electrodes are wound; an electrolyte; a bottomed cylindrical exterior can that houses the electrode body and the electrolyte; and an opening sealing body. The opening sealing body includes a terminal cap, a valve disc included in a current cut-off mechanism, and a washer having an opening at a center, interposed between the terminal cap and the valve disc, the washer has a recessed section formed in surroundings of the opening and a planar section disposed in surroundings of the recessed section on each of surfaces at both ends in a thickness direction of the washer, and boundary lines each between the recessed section and the planar section of each of the surfaces of the washer are arranged to be overlapped with each other in the thickness direction.