Insulative Polymer Battery Housing with Crimp Seal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional button cell batteries with metallic housings are not easily shape-adaptable and are susceptible to electromagnetic interference, limiting their use in medical applications, particularly in MRI environments, due to the reliance on radial force for sealing and the susceptibility of metals to magnetic fields.
Innovation Solution
An electrochemical device with a housing made from insulative materials, such as polymers, secured by a crimp ring and grommet, which reduces electromagnetic interference and allows for non-circular shapes, providing a hermetic seal with a low leak rate and electrical connectivity through co-molded feedthroughs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic housing segments are used to provide both protection and electrical contacts, then electrical connectivity and environmental protection are achieved, but susceptibility to electromagnetic interference increases
Solution Approach 1:
The housing is divided into two distinct functional segments: an insulative housing body that provides environmental protection, and separate conductive feedthrough elements that provide electrical connectivity. This segmentation allows each component to perform its specialized function without the compromises required by a unified metallic housing.
Solution Approach 2:
The insulative housing material acts as an intermediary between the electrochemical cell and the external environment, blocking electromagnetic fields while still allowing electrical connections to be made through dedicated feedthrough paths. This intermediary structure resolves the conflict between electromagnetic shielding and electrical functionality.
2Reliability
If radial force is used to create friction fit between housing segments, then effective sealing is achieved, but shape adaptability is limited to circular forms
Solution Approach 1:
The traditional radial friction-fit mechanical system is replaced with a crimping mechanism that applies localized compressive force through a crimp ring. This substitution allows the sealing mechanism to function effectively with non-circular cross-sections, as the crimping action can be applied along the entire perimeter regardless of shape.
Solution Approach 2:
The sealing approach transitions from relying on radial force in a planar circular geometry to using circumferential crimping force that can accommodate arbitrary cross-sectional shapes. This dimensional generalization allows the same sealing principle to work for rectangular, oval, or irregular shapes.
3Adaptability or versatility
If welding is used to secure housing segments, then non-circular shapes are enabled and electromagnetic susceptibility is reduced, but manufacturing cost increases
Solution Approach 1:
The crimp ring structure is designed to be self-securing through the crimping process itself, which deforms the ring to lock the housing segments together without requiring additional welding operations or specialized equipment. This self-service approach simplifies manufacturing while maintaining structural integrity.
Solution Approach 2:
The connection method changes from thermal welding parameters to mechanical crimping parameters. This parameter change allows for cold-form assembly that is both cost-effective and suitable for non-circular geometries, avoiding the high costs and complexity of laser welding while achieving equivalent or superior joint strength.
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 solution effectively reduces electromagnetic interference and provides a reliable, hermetically sealed, shape-adaptable electrochemical device with improved manufacturing feasibility and reduced susceptibility to MRI fields, while maintaining effective electrical connections.
Implementation Method 1
crimping the crimp ring to engage with the first rim of the first housing portion and the second rim of the second housing portion to secure the first housing portion with respect to the second housing portion
Implementation Method 2
A grommet may contribute to sealing the enclosure
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Electrochemical device and method for assembling an electrochemical device. The electrochemical device has an electrochemical module and an enclosure configured to enclose the electrochemical module. The enclosure has a first housing portion forming a first rim and being an insulative material and a second housing portion forming a second rim and being the insulative material, the first housing portion and the second housing portion at least partially forming, when the first rim substantially abuts the second rim, a volume configured to enclose the electrochemical device. The enclosure further has a crimp ring engaging the first rim and the second rim, the crimp ring securing the first housing portion with respect to the second housing portion and a grommet positioned between and contacting the first rim and the second rim. The enclosure is substantially sealed.