Busbar Insulating Polyamide Coating for Thin Flame-Retardant Coverage
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Solution Overview
Problem
Existing technologies face challenges in forming a thin, fire-resistant polymer layer for electric battery busbars that maintains flexibility and resistance to mechanical stresses and aging, while also ensuring electrical insulation and abrasion resistance.
Innovation Solution
A flame-retarded insulating composition comprising a specific blend of semi-crystalline aliphatic polyamides, semi-aromatic polyamides, phosphinate flame retardants, functionalized polyolefins, plasticizers, and additives, which provides the necessary balance of fire resistance, flexibility, and electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a thin polymer layer is used for covering busbars, then the coating thickness is reduced, but fire resistance deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of semi-aromatic polyamide (providing inherent flame resistance), phosphinate flame retardant (enhancing fire resistance), and functionalized polyolefin (improving flexibility and adhesion). This composite formulation achieves UL94 V0 fire rating at thin thicknesses by combining materials with complementary properties rather than relying on a single thick layer.
Solution Approach 2:
The patent modifies the chemical composition parameters of the polymer system by incorporating specific ratios of semi-aromatic polyamide (30-65 wt%), phosphinate flame retardant (15-30 wt%), and functionalized polyolefin (5-20 wt%). These parameter changes in the material formulation enable thin coatings to achieve fire resistance that would normally require greater thickness.
2Reliability
If the polymer coating is made rigid for fire resistance, then fire resistance is improved, but flexibility deteriorates
Solution Approach 1:
The patent creates a flexible fire-resistant composite by combining semi-aromatic polyamide (rigid, fire-resistant) with functionalized polyolefin (flexible, elastic) and plasticizers. The polyolefin component with elastic properties and the plasticizer molecules intercalated between polymer chains provide flexibility and elongation at break >50%, allowing the coating to deform with busbar bending without cracking while maintaining fire resistance.
Solution Approach 2:
The patent adjusts the physical and chemical parameters of the coating by controlling the glass transition temperature and molecular mobility through plasticizer content (0-6 wt%) and polyolefin composition. These parameter changes enable the coating to maintain a rubbery, flexible state at operating temperatures while preserving fire resistance through the semi-aromatic polyamide backbone structure.
3Reliability
If phosphinate flame retardant is added to polyamide, then fire resistance is improved, but elongation at break deteriorates
Solution Approach 1:
The patent introduces functionalized polyolefin as an intermediary component between the rigid semi-aromatic polyamide and phosphinate flame retardant. This intermediary phase acts as a plasticizing agent and flexibility enhancer, allowing the flame-retarded polyamide matrix to maintain elongation at break >50% by providing a flexible continuous phase that accommodates deformation while the flame retardant provides fire protection.
Solution Approach 2:
The patent formulates a three-component composite system where semi-aromatic polyamide provides fire resistance, phosphinate flame retardant enhances flame inhibition, and functionalized polyolefin with plasticizer maintains flexibility. This composite approach balances the competing requirements of fire resistance and elongation by distributing functions across multiple materials rather than relying on a single component.
4Reliability
If glass fiber reinforcement is added to achieve UL94 V0, then fire resistance is improved, but manufacturing complexity and processing difficulty increase
Solution Approach 1:
The patent extracts and eliminates the glass fiber reinforcement component from the formulation, achieving UL94 V0 fire rating through a fiber-free composite system. This removal of reinforcing fibers simplifies manufacturing, eliminates processing difficulties associated with fiber handling and distribution, and reduces device complexity while maintaining fire resistance through the chemical composition of semi-aromatic polyamide and phosphinate flame retardant.
5Adaptability or versatility
If the coating is made thin for flexibility, then flexibility is improved, but electrical insulation deteriorates
Solution Approach 1:
The patent uses a composite formulation where semi-aromatic polyamide provides inherent electrical insulation properties, phosphinate flame retardant maintains insulating characteristics, and functionalized polyolefin ensures flexible adhesion. This composite system maintains high dielectric strength and breakdown voltage even at thin coating thicknesses by combining materials with complementary electrical and mechanical properties.
Solution Approach 2:
The patent optimizes the chemical composition parameters to achieve high electrical insulation in thin sections. The semi-aromatic polyamide structure with aromatic rings provides high dielectric strength, and the controlled addition of phosphinate flame retardant and functionalized polyolefin maintains insulating properties while enabling flexibility and adhesion at reduced thicknesses.
Data Source
AI summary
The present invention relates to a flame retarded insulating composition for covering electric battery busbars, comprising by weight: (a) from 30 to 65%, more particularly from 30 to 63.9%, in particular from 30 to 60%, of at least one semi-crystalline aliphatic polyamide, (b) from 15 to 40%, more particularly from 15 to 30%, of at least one semi-aromatic polyamide, (c) from 15 to 30%, more particularly from 20 to 25%, of at least one phosphinate flame retardant, (d) from 5 to 20%, more particularly from 5 to 15%, of at least one functionalized polyolefin, (e) from 0 to 6%, more particularly from 1 to 6%, in particular between 2 and 4%, of at least one plasticizer, (f) from 0 to 10%, more particularly 10 from 0.1 to 5%, of at least one additive, the sum of the constituents (a) to (f) being equal to 100%.