Nonwoven Fibrous Web Assembly for EV Battery Flame Insulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Developers of insulation materials for EV battery applications face challenges in creating materials that exhibit low thermal conductivity, strict flame-retardant requirements, resilience to flex and compress, mechanical strength, and tear resistance, while minimizing fiber shedding and requiring no additional sealing or processing for irregularly shaped enclosures.
Innovation Solution
A nonwoven fibrous web assembly comprising a flame-resistant foam with oxidized polyacrylonitrile fibers and reinforcing fibers, bonded with a polyvinyl alcohol foam coated with ammonium polyphosphate or sodium metasilicate, which provides cohesive strength, low thermal conductivity, and acoustic insulation without fiber shedding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional thermal insulation materials are used to protect EV batteries, then thermal insulation performance is improved, but flame resistance is insufficient
Solution Approach 1:
The patent uses a composite structure combining foam core material with nonwoven fabric layers containing flame-retardant fibers. This multi-material composite approach allows the foam to provide thermal insulation while the fabric layers with minerals like alumina trihydrate and magnesium hydroxide provide flame resistance, resolving the contradiction between insulation performance and fire safety
Solution Approach 2:
The patent modifies the chemical composition parameters of the foam material by incorporating flame-retardant additives and adjusting the cellular structure. The foam's thermal and chemical parameters are optimized to achieve both low thermal conductivity for insulation and high decomposition temperature for flame resistance
2Weight of moving object
If vehicle weight is reduced to improve fuel economy, then fuel efficiency is improved, but noise from structural vibrations increases
Solution Approach 1:
The patent employs porous foam materials with controlled cell structures that provide vibration damping properties. The porous structure absorbs vibrational energy while maintaining low weight, thus reducing noise from structural vibrations without adding significant mass to the vehicle
Solution Approach 2:
The patent applies damping materials with specific local properties at strategic locations around the battery compartment. The nonwoven fabric layers with flame-retardant fibers are positioned to provide both acoustic damping and thermal protection where needed most, optimizing noise reduction without uniformly increasing vehicle weight
3Weight of moving object
If thin and lightweight thermal insulation materials are used, then fuel economy is improved, but mechanical strength and tear resistance are insufficient
Solution Approach 1:
The patent creates a composite structure where a lightweight foam core is reinforced with nonwoven fabric layers. This composite design maintains the low weight of the foam while the fabric layers provide the necessary mechanical strength and tear resistance, resolving the contradiction between weight reduction and structural integrity
Solution Approach 2:
The patent divides the insulation system into multiple functional layers: a foam core for thermal insulation and lightweight properties, and outer nonwoven fabric layers for mechanical protection. This segmentation allows each layer to optimize its specific function while working together to provide both lightness and strength
4Reliability
If flame-retardant coatings are applied to foam materials, then flame resistance is improved, but fiber shedding increases
Solution Approach 1:
The patent uses a composite structure where flame-retardant properties are provided by mineral-containing nonwoven fabric layers rather than surface coatings. This integrated approach incorporates flame resistance into the bulk material structure, preventing the fiber shedding problem associated with applied coatings while maintaining effective flame protection
Solution Approach 2:
The patent employs sacrificial flame-retardant fibers that decompose to form a protective char layer during fire exposure. These fibers are designed to be consumed in the fire resistance process, providing effective flame protection without requiring durable surface coatings that would shed
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 passes flame tests, maintains structural integrity, and offers improved thermal insulation and acoustic performance, reducing the need for additional sealing and enhancing handling and installation in EV battery compartments.
Implementation Method 1
from 25 to 95 wt % fire retardant coated on the polyvinyl alcohol foam, wherein the fire retardant comprises ammonium polyphosphate or sodium metasilicate
Implementation Method 2
at least 60 wt% of oxidized polyacrylonitrile fibers
Implementation Method 3
from 0 to less than 40 wt% of reinforcing fibers having an outer surface comprised of a (co)polymer with a melting temperature of from 100°C to 350°C
Data Source
Figure 1
AI summary
A flame retardant foam. The flame retardant foam includes a from 25 to 75 wt % polyvinyl alcohol foam; and a from 25 to 95 wt % fire retardant coated on the polyvinyl alcohol foam, wherein the fire retardant comprises ammonium polyphosphate or sodium metasilicate; wherein the thickness of the foam is from 2 mm to 1 cm.