Battery Pack Composite Insulator for Flame and Dielectric Isolation
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Solution Overview
Problem
Existing thermal insulation materials for battery packs, such as fiberglass fabric, fail to adequately inhibit flame propagation within and between cells of the battery pack, particularly during thermal runaway conditions, and lack sufficient dielectric protection.
Innovation Solution
A composite thermal insulator comprising a scrim reinforced polyether ether ketone layer, a pressure sensitive adhesive layer, and a silica fabric with optional silicone rubber or polyether ether ketone layer, designed to prevent flame propagation and provide dielectric protection, with a maximum thickness of 5mm or 2mm to minimize space and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fiberglass fabric insulation is used, then thermal insulation and contamination protection are provided, but flame propagation protection is insufficient
Solution Approach 1:
The patent employs a composite insulation structure consisting of multiple layers including fiberglass fabric, scrim, and flame-resistant polymer layers. Each layer contributes specific properties: fiberglass provides thermal insulation, scrim provides structural stability, and the flame-resistant polymer layer (containing materials like polyether ether ketone or polyphenylene oxide) provides flame propagation resistance. This composite approach resolves the contradiction by combining materials that individually address different aspects of the problem, achieving both thermal insulation and flame protection.
Solution Approach 2:
The patent modifies the thermal and chemical parameters of the insulation material by incorporating flame-retardant additives and selecting materials with specific flame resistance ratings. The insulation layer is designed to maintain structural integrity at temperatures up to 1000°C for extended periods (5-10 minutes), changing the temperature-time parameter profile to prevent flame propagation while maintaining thermal insulation properties.
2Reliability
If insulation thickness is increased to improve flame protection, then flame propagation is inhibited, but space and weight increase
Solution Approach 1:
The composite structure allows achieving high flame resistance with a relatively thin total thickness by combining multiple functional layers. Rather than using a single thick layer of one material, the patent distributes protective functions across several thinner layers, each optimized for its specific function. This reduces the overall weight while maintaining or improving flame protection performance.
Solution Approach 2:
The insulation design applies different material properties at different locations and layers. The flame-resistant polymer layer is strategically positioned to provide flame barrier function where needed, while other layers provide thermal insulation and structural support. This localized optimization allows achieving high flame protection with minimal material usage and weight.
3Reliability
If fiberglass fabric is used for thermal insulation, then thermal protection is provided, but dielectric protection is insufficient
Solution Approach 1:
The composite insulation structure incorporates materials with high dielectric strength properties alongside the thermal insulation materials. The flame-resistant polymer layers and scrim materials are selected to provide both thermal and electrical insulation functions, creating a multi-functional barrier that addresses both heat transfer and electrical breakdown risks in battery pack environments.
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 insulator effectively inhibits flame propagation for up to 10 minutes at 1000 °C, maintains electrical insulation resistance, and provides dielectric strength, ensuring safety and design flexibility for electric vehicle battery packs.
Implementation Method 1
a first pressure sensitive adhesive layer coated on a side of the scrim reinforced, polyether ether ketone layer, and a silica fabric bonded to the pressure sensitive adhesive
Implementation Method 2
thermal insulator for inhibiting flame propagation within and from a battery pack
Implementation Method 3
provide dielectric protection to the battery pack
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
A flexible thermal insulator (10) for an electric vehicle battery pack (12), and an electric vehicle battery pack (12) therewith is provided. The flexible thermal insulator (10) has a composite wall including a sheet of fire-resistant material having opposite first and second sides. A first pressure sensitive adhesive layer is bonded to the first side of the sheet of fire-resistant material. Further, one of a scrim reinforced, polyether ether ketone layer is bonded to the second side of the fire- resistant material, or a silicone rubber layer is bonded to the second side of the fire-resistant material.