Polyamide Composition for Low-Temperature Battery Overmoulding

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Solution Overview

Problem

Conventional polyamide compositions used in low-pressure overmoulding processes are unsuitable for heat-sensitive lithium-polymer batteries due to high temperature requirements and lack of mechanical and thermal properties, and they do not facilitate easy recycling.

Innovation Solution

A polyamide composition derived from the polycondensation of an acid component comprising fatty acid dimers, aliphatic diacids, and an amine component with cycloaliphatic and aliphatic diamines, which has a viscosity of less than 4 Pa·s at 185° C. and a softening point between 150° C. to 170° C., enabling low-pressure and low-temperature injection while maintaining mechanical and thermal properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional polyamide compositions are used for low-pressure overmoulding, then the process can be implemented, but the high temperature requirements (>200°C) damage heat-sensitive lithium-polymer batteries

Engineering Contradiction:
Improveovermoulding process feasibilityVSAvoidinjection temperature
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent modifies the chemical composition parameters of the polyamide by incorporating specific ratios of fatty acid dimers (30-50 mol%), aliphatic diacids (30-50 mol%), cycloaliphatic diamines (10-40 mol%), and aliphatic diamines (50-80 mol%). This compositional parameter change reduces the melting point from conventional >200°C to 150-170°C, enabling low-temperature injection that protects heat-sensitive batteries while maintaining manufacturability.

Inventive Principle:
Principle #35Parameter changes

2Strength

If high temperature injection is used to ensure good mechanical properties, then the polyamide achieves sufficient strength, but the heat-sensitive battery is damaged

Engineering Contradiction:
Improvemechanical strengthVSAvoidthermal damage to battery
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent creates a composite polyamide system combining multiple components: fatty acid dimers, aliphatic diacids, cycloaliphatic diamines, and aliphatic diamines in specific proportions. This composite material achieves optimal balance between mechanical strength (tensile strength ≥3 MPa, elongation at break ≥80%) and thermal properties (softening point 150-170°C), allowing injection below battery damage thresholds while maintaining structural integrity.

Inventive Principle:
Principle #40Composite materials

3Productivity

If conventional polyamide compositions are used, then the overmoulding process can be completed, but the resulting product is difficult to recycle

Engineering Contradiction:
Improveovermoulding completionVSAvoidrecyclability
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent designs the polyamide composition with recyclability as a key feature. The specific combination of components (fatty acid dimers, aliphatic diacids, cycloaliphatic diamines, aliphatic diamines) creates a material that maintains good processability for complete overmoulding while enabling easy recycling through controlled degradation or reprocessing at lower temperatures, facilitating battery recycling when electronic devices break down.

Inventive Principle:
Principle #34Discarding and recovering

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 polyamide composition allows for the successful overmoulding of heat-sensitive batteries with improved mechanical and thermal properties, including high tensile strength and elongation at break, and facilitates easy removal from moulds, while also being recyclable.

Implementation Method 1

a polyamide which is the product of the polycondensation of an acid component and of an amine component

Methodology Applied
Scientific EffectPolycondensation: Chemical Bonding

Implementation Method 2

a viscosity of less than or equal to 4 Pa·s at 185° C.

Methodology Applied
Scientific EffectThermal thinning:

Implementation Method 3

a softening point ranging from 150° C. to 170° C.

Methodology Applied
Scientific EffectSoftening: Melting

Data Source

PatentUS20250092199A1Polyamide composition
Publication Date: 2025.03.20 BOSTIK SA(FR)

AI summary

The present invention relates to a polyamide composition comprising a polyamide which is the poly condensation product of an acid component and an amine component, the acid component comprising, per mole of acid component; −30 to 50 mol. % of fatty acid dimer(s); −30 to 50 mol. % of aliphatic dibasic acid(s); −0 to 10 mol. % of chain limiter(s); the amine component comprising, per mole of amine component; −10 to 40 mol. % of cycloaliphatic diamine(s); and −50 to 80 mol. % of aliphatic diamine(s) comprising 3 to 12 carbon atoms); −0 to 15 mol. % of polyetheramine(s); said polyamide composition having; —a viscosity less than or equal to 4 Pa·s at 185° C.; and —a softening temperature ranging from 150° C. to 170° C.