Electrical Feedthrough Insulation Bonding for Low-Temperature Sealing
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Solution Overview
Problem
Existing electrical feedthrough assemblies face challenges in maintaining a stable and reliable adhesive bond between insulation elements and fixation materials, particularly at low temperatures, leading to gap formation and potential short circuits due to mechanical strain and infiltration by operating media.
Innovation Solution
The use of ethylene propylene diene monomer (EPDM) rubber, hydrogenated nitrile-butadiene rubber (HNBR), or fluoroelastomer materials for insulation elements, combined with specific adhesive materials, is designed to ensure a gap-free and air-tight connection by controlling thermal expansion differences and adhesive thickness within a defined temperature range, minimizing mechanical strain and enhancing electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive bonding is used to attach insulation elements to base body or fixation material, then attachment process becomes easy and quick, but bond stability deteriorates at low temperatures due to material brittleness and thermal expansion differences
Solution Approach 1:
The patent specifies precise parameter ranges for the adhesive material including glass transition temperature (-50°C to 0°C), coefficient of thermal expansion (10-100×10^-6/K), and thickness (0.1-1.0mm) to ensure the adhesive remains flexible and maintains bond stability across the operating temperature range of -45°C to 120°C, preventing the brittleness and gap formation that occurs with conventional adhesives at low temperatures
Solution Approach 2:
The patent employs a composite structure consisting of multiple materials with complementary properties: the insulation element (rubber or plastic), the adhesive material (with specific viscoelastic properties), and the fixation material (glass or ceramic). This composite approach allows each material to contribute its strengths, with the adhesive acting as a buffer that accommodates thermal expansion differences between the rigid insulation element and the base body, thereby maintaining bond reliability across temperature cycles
2Stability of the object's composition
If insulation element and adhesive material are hard and not resilient at low temperatures, then structural stability is improved, but mechanical strain increases causing gap formation and bond weakening
Solution Approach 1:
The patent carefully selects the glass transition temperature of the adhesive material to be between -50°C and 0°C, ensuring that within the operating temperature range of -45°C to 120°C, the adhesive remains in a rubbery state with adequate flexibility and resilience. This parameter optimization allows the adhesive to absorb mechanical strain from thermal expansion and contraction without becoming brittle, thereby maintaining bond strength while providing structural stability
Solution Approach 2:
The adhesive material serves as a pre-designed cushioning layer between the insulation element and the base body or fixation material. This cushioning layer is specifically engineered with appropriate thickness (0.1-1.0mm) and material properties to absorb and distribute mechanical strains arising from thermal expansion and contraction, preventing stress concentration that would lead to gap formation and bond failure at low temperatures
3Manufacturing precision
If adhesive layer is thin, then assembly precision is improved, but resistance to mechanical strain and infiltration by operating media deteriorates
Solution Approach 1:
The patent defines an optimized thickness range for the adhesive layer of 0.1-1.0mm, with preferred ranges of 0.2-0.5mm. This parameter optimization balances two competing requirements: sufficient thickness to provide mechanical cushioning, resist strain, and prevent infiltration by operating media, while maintaining thin enough dimensions to ensure assembly precision and minimize thermal expansion differences. The specified range ensures adequate bond reliability without excessive thickness that would compromise manufacturing precision
4Reliability
If adhesive layer is thick, then resistance to mechanical strain and infiltration is improved, but assembly precision and thermal expansion control deteriorate
Solution Approach 1:
The patent optimizes the adhesive layer thickness to a maximum of 1.0mm, with preferred ranges of 0.2-0.5mm. This parameter control ensures that the adhesive layer is thick enough to provide adequate mechanical cushioning and resistance to strain and infiltration, while remaining thin enough to maintain assembly precision and minimize the overall thermal expansion of the feedthrough assembly. Excessive thickness beyond 1.0mm would compromise manufacturing precision and increase thermal expansion, so the specified upper limit balances these competing requirements
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 results in a mechanically stable, environmentally resistant, and airtight feedthrough assembly that reduces the risk of short circuits and maintains insulation integrity even in harsh environments, ensuring high electrical resistance and chemical stability.
Implementation Method 1
The electrical feedthrough assembly comprises at least one insulation element which is affixed by means of an adhesive material arranged between the at least one insulation element and the base body and/or the fixation material
Implementation Method 2
A fixation material, for example a glass material, is used to seal the opening and to hold the conductor within the opening. The fixation material also provides an electrical insulation between the conductor and the housing
Implementation Method 3
The insulation element at least partially surrounds the conductor and enlarges a so-called creepage distance between a conductor and the housing and/or between two conductors
Implementation Method 4
Within an operating temperature range of from -45°C to 120°C, preferably from -55°C to 150°C, an absolute value of the difference between a first coefficient of thermal expansion of the adhesive material α1 and a second coefficient of thermal expansion of the fixation material α2 is in the range of from 10 · 10^-6 to 100 · 10^-6 1/K
Data Source
Figure 1~2
Figure 3~5
Figure 6(a)~6(d)
AI summary
An electrical feedthrough assembly (1) is proposed. The electrical feedthrough assembly (1) comprises a base body (10) with at least one opening (14) for at least one conductor (12) embedded in a fixation material (16) that is fed into each of the respective openings (14) and sealing the respective opening (14), wherein said electrical feedthrough assembly (1) further comprises at least one insulation element (20) made from a material having a first glass-transition temperature tg1, wherein the at least one insulation element (20) is affixed by means of an adhesive material (40) arranged between the at least one insulation element (20) and the fixation material (16).