Silver Oxide Battery Negative Canister Double-Step Curvature
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Solution Overview
Problem
The challenge is to prevent electrolytic solution leakage in smaller and thinner alkaline primary batteries and flat cylindrical electrochemical cells, where reducing the thickness of the negative electrode canister compromises mechanical strength and leads to deformation and leakage issues during the swaging process.
Innovation Solution
The electrochemical cell design features a negative electrode canister with a double-step cylindrical shape, having decreasing inner diameters and specific curved surfaces, with a bend angle between 15° to 45°, which reduces deformation and prevents gaps between canisters, thereby enhancing anti-leak properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the negative electrode canister is reduced to make the battery smaller and thinner, then the size and thickness of the battery are reduced, but the mechanical strength of the negative electrode canister is lowered, causing deformation and electrolytic solution leakage during swaging
Solution Approach 1:
The negative electrode canister is designed with a double-step cylindrical shape featuring curved surfaces with specific radii of curvature (R1 for the first cylindrical portion, R2 for the second cylindrical portion). These curved surfaces distribute stress more evenly during the swaging process, preventing localized deformation and maintaining structural integrity even when the canister wall thickness is reduced. The curvature design allows the canister to better absorb and distribute the compressive forces applied during sealing, thereby preventing electrolytic solution leakage while maintaining a compact battery size.
2Length of stationary object
If the thickness of the negative electrode canister is reduced, then the battery becomes thinner, but the negative electrode canister becomes susceptible to deformation upon swaging, causing leaking of electrolytic solution
Solution Approach 1:
The double-step cylindrical design with optimized curvature radii (R1 and R2) creates a structure that resists deformation during swaging. The curved surfaces prevent stress concentration that would otherwise occur in straight-walled cylindrical designs, especially when wall thickness is reduced. This geometric optimization maintains the seal integrity between the positive and negative electrode canisters, preventing electrolytic solution leakage while achieving the desired thin profile for compact battery applications.
3Ease of manufacture
If the negative electrode canister has a simple cylindrical shape, then the manufacturing is simpler, but the canister deforms easily during swaging and creates gaps between canisters
Solution Approach 1:
The double-step cylindrical shape with specific curvature radii (R1 for the upper portion, R2 for the lower portion) provides enhanced dimensional stability during the swaging process. The curved surfaces guide the deformation more uniformly, preventing the canister from buckling or creating gaps with the positive electrode canister. While this design requires additional manufacturing steps compared to a simple cylinder, the process remains compatible with conventional metal forming techniques, achieving a balance between manufacturability and dimensional precision.
Data Source
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AI summary
An electrochemical cell of improved anti-leak property is provided. A silver oxide battery includes: a positive electrode canister (11) having a form of a cylinder with a bottom portion (11a); a negative electrode canister (12) having a form of a cylinder with a lid portion (12a) and being contained in the positive electrode canister; and an electrolytic solution contained within a space formed by the positive electrode canister and the negative electrode canister. The negative electrode canister is formed into a shape of a double-step cylinder having decreasing inner diameters toward the lid portion. The double-step cylinder has a first cylindrical portion that defines a cylindrical portion closer to the lid portion, and a second cylindrical portion that defines a cylindrical portion farther from the lid portion. The first cylindrical portion has a first inner curved surface (21is) that projects out at a first apex (P1). The second cylindrical portion has a second inner curved surface (22is) that projects out at a second apex (P2). The angle made by the bottom portion (11a) and the straight line (A) connecting the first apex and the second apex to each other ranges from 15° to 45°.