Small Diameter High Voltage Wire Insulation
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Solution Overview
Problem
High voltage wires for hybrid and electric vehicles face challenges in achieving sufficient heat aging resistance, flexibility, and wear resistance while being halogen-free and environmentally friendly, with existing solutions either lacking in flexibility, using costly materials, or increasing environmental load due to halogenated flame retardants.
Innovation Solution
A small diameter high voltage insulated electric wire with an insulating layer composed of a copolymer resin of ethylene and acrylic ester and polyethylene, blended with a metal hydroxide flame retardant, optimized for a balance of tensile break strength, break elongation, storage elastic modulus, and hardness, ensuring flexibility and wear resistance while minimizing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a cross-linked thin-walled wire with non-halogenated flame retardant is used, then environmental load is reduced, but heat-resistant temperature is insufficient
Solution Approach 1:
The patent uses a composite material system combining polyethylene base resin with ethylene copolymer resin and specific additives (cross-linking agent, flame retardant, antioxidant) to achieve both halogen-free composition and high heat resistance. This composite approach allows the insulating layer to withstand temperatures of 150°C or higher while maintaining environmental friendliness.
Solution Approach 2:
The patent changes the chemical composition parameters of the insulating layer by specifying precise proportions of polyethylene (80-95 parts by weight) and ethylene copolymer resin (5-20 parts by weight), along with controlled amounts of cross-linking agent and flame retardant. These parameter adjustments enable the material to achieve both low environmental impact and high heat resistance.
2Temperature
If a cross-linked heat-resistant wire with bromine-based flame retardant is used, then heat resistance is improved, but flexibility deteriorates and environmental load increases
Solution Approach 1:
The patent extracts and eliminates bromine-based flame retardants from the composition, replacing them with halogen-free alternatives (such as aluminum hydroxide, magnesium hydroxide, or boron compounds). This removal solves both the environmental pollution problem and the flexibility deterioration issue while maintaining heat resistance through the copolymer resin system.
Solution Approach 2:
The patent employs cost-effective, environmentally benign materials (common metal hydroxides as flame retardants) that can be easily disposed of or recycled, replacing expensive and harmful bromine-based compounds. This approach reduces both environmental load and material cost while maintaining performance.
3Temperature
If a cross-linked heat-resistant wire with fluororesin is used, then heat resistance is sufficient, but cost increases and flexibility deteriorates
Solution Approach 1:
The patent replaces expensive fluororesin with inexpensive polyethylene and ethylene copolymer resin combinations that can achieve comparable heat resistance through cross-linking. This substitution dramatically reduces material cost while maintaining the required 150°C or higher heat resistance and improving flexibility.
Solution Approach 2:
The patent changes the material composition parameters from fluororesin-based to polyethylene-based systems with controlled cross-linking degrees. By adjusting the copolymer content (5-20 parts by weight) and cross-linking agent amounts, the material achieves heat resistance equivalent to fluororesin at a fraction of the cost with superior flexibility.
4Ease of manufacture
If polyethylene and polypropylene are used to reduce cost, then manufacturing cost is reduced, but heat aging resistance at 150°C for 3000 hours cannot be satisfied
Solution Approach 1:
The patent applies cross-linking agents and antioxidants in advance during the compounding process, creating a pre-prepared insulating layer composition that inherently resists heat aging. This preliminary chemical modification enables the inexpensive polyethylene base to achieve 3000-hour heat aging resistance at 150°C without requiring expensive high-performance resins.
Solution Approach 2:
The patent creates a composite system where polyethylene base resin is enhanced with ethylene copolymer resin (providing flexibility and processability) and specific additives (cross-linking agents like peroxides, flame retardants, and antioxidants). This composite structure achieves both cost-effectiveness and 3000-hour heat aging resistance that neither component could achieve alone.
5Strength
If wear resistance is improved by using high elastic modulus material, then wear resistance is improved, but flexibility cannot be secured
Solution Approach 1:
The patent uses a composite system where hard polyethylene base resin (providing wear resistance) is combined with softer ethylene copolymer resin (providing flexibility). The copolymer acts as a matrix that binds the harder components while maintaining overall flexibility, achieving both wear resistance and bendability in the insulating layer.
Solution Approach 2:
The patent creates local quality differentiation within the insulating layer by distributing ethylene copolymer resin (flexible component) throughout the polyethylene matrix (wear-resistant component). This local distribution of different material properties ensures that wear-resistant regions maintain overall flexibility through the continuous flexible matrix phase.
Data Source
AI summary
A thin high-voltage insulted electric wire which comprises a conductor and an insulating layer covering the conductor, said insulating layer comprising both an ethylene-acrylic ester copolymer resin and polyethylene. The insulating layer is made of a composition which exhibits a reciprocal of the product of tensile break strength (σf) (MPa) and tensile break elongation (ε), 1/(σf·ε), of 4.8×10−2 or less [wherein σf refers to the tensile break strength of the insulating layer and ε refers to the tensile break elongation thereof], a storage elastic modulus (E) of 520 MPA or more, and a D hardness of 45 or more.