Aerogel-Nonwoven Heat Insulating Sheet for High-Load Battery Modules
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Solution Overview
Problem
Conventional heat insulating sheets, such as those using silica aerogel, lack both high compressive strength and effective thermal resistance, particularly under high loads, which is critical for preventing heat chain reactions in battery modules where space is limited and thermal runaway is a safety concern.
Innovation Solution
A heat insulating sheet comprising a high-density aerogel and nonwoven fibers, synthesized using a water glass composition with a silica concentration of 14-22% and a gelling agent like carbonate ester, which enhances the sheet's compressive strength and thermal resistance while maintaining a low thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If silica aerogel is used as heat insulating material, then thermal conductivity is reduced, but strength under compression is extremely low
Solution Approach 1:
The patent combines silica aerogel particles with a binder matrix to create a composite heat insulating sheet. The aerogel provides low thermal conductivity while the binder provides structural strength, resolving the contradiction between insulation performance and mechanical strength.
Solution Approach 2:
The patent controls the particle size of silica aerogel (1-100 μm) and adjusts the binder content and composition to optimize both thermal insulation properties and compressive strength, achieving a balance between these two opposing requirements.
2Reliability
If material thickness is increased to prevent heat chain, then fire resistance is improved, but space for battery module is reduced
Solution Approach 1:
The patent reduces thermal conductivity to extremely low values (0.03-0.08 W/m·K) through aerogel incorporation, enabling thin sheet designs (1-5 mm) that provide adequate fire resistance without occupying excessive space in the battery module.
Solution Approach 2:
The aerogel-based porous structure provides exceptional thermal insulation in a thin profile, allowing the heat insulating sheet to achieve effective fire protection while maintaining minimal thickness for space-constrained battery applications.
3Volume of moving object
If heat insulating sheet thickness is reduced for miniaturization, then space is saved, but compression strength under load is reduced
Solution Approach 1:
The binder matrix in the composite structure provides mechanical strength while the aerogel particles provide thermal insulation, enabling thin sheets to maintain adequate compression strength under battery expansion loads despite reduced thickness.
Solution Approach 2:
The patent optimizes the local distribution and concentration of aerogel particles within the binder matrix to achieve uniform mechanical properties and compression resistance throughout the thin sheet structure.
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 resulting heat insulating sheet effectively suppresses heat transfer and maintains structural integrity under high loads, ensuring safety by preventing thermal runaway in battery modules and other applications where space is constrained.
Implementation Method 1
a composite generating step of impregnating a nonwoven fiber with a basic sol prepared to generate a composite of a hydrogel-nonwoven fiber, the basic sol being prepared by adding carbonate ester to a water glass composition
Implementation Method 2
a drying step of drying a liquid contained in the composite at a temperature lower than a critical temperature of the liquid and a pressure lower than a critical pressure of the liquid to remove the liquid from the composite
Implementation Method 3
The silica aerogel has a network structure in which silica particles in the order of several tens of nm are connected in point contact. For this reason, an average pore diameter of the silica aerogel is 68 nm or less in a mean free path of air. That is, the thermal conductivity of silica aerogel is lower than a thermal conductivity of stationary air.
Data Source
AI summary
A manufacturing method of a heat insulating sheet of the present disclosure includes a composite generating step of impregnating a nonwoven fiber with a basic sol prepared to generate a composite of a hydrogel-nonwoven fiber, the basic sol being prepared by adding carbonate ester to a water glass composition; and a drying step of drying a liquid contained in the composite at a temperature lower than a critical temperature of the liquid and a pressure lower than a critical pressure of the liquid to remove the liquid from the composite. A heat insulating sheet according to the present disclosure includes an aerogel and a nonwoven fiber, and has a compression rate at 0.30 MPa to 5.0 MPa of 40% or less. In an electronic device of the present disclosure, the heat insulating sheet is disposed between an electronic component and a housing. In a battery unit of the present disclosure, the heat insulating sheet is disposed between batteries. This provides a heat insulating sheet that can be used under a high load and a manufacturing method thereof, and an electronic device and a battery unit including the same.