Battery Pack Insulating Sheet for High-Temperature Compression
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Solution Overview
Problem
Existing heat-insulating sheets for battery packs fail to maintain effective heat-insulating performance at high temperatures above 500°C and are susceptible to degradation under compressive stress, which can lead to thermal runaway and safety issues such as fire or explosion.
Innovation Solution
A heat-insulating sheet composed of a mixture of silica nanoparticles and metal oxide particles, with a silica nanoparticle content of 60-95% and a metal oxide content of 5-40%, where the silica nanoparticles have a diameter of 1-100 nm and the metal oxide particles have a diameter of 0.1-50 μm, providing enhanced thermal resistance and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a low thermal conductive layer (air layer) is used between battery cells, then heat propagation is suppressed, but mechanical strength is insufficient to resist repeated pressing forces
Solution Approach 1:
The patent uses a composite structure combining a heat-insulating sheet (providing mechanical strength) with an air layer (providing thermal insulation). The heat-insulating sheet is made of compressible material that can withstand repeated pressing forces while maintaining the integrity of the air layer, thus resolving the contradiction between mechanical strength and heat insulation performance.
Solution Approach 2:
The air layer is nested within the battery cell structure, surrounded by the heat-insulating sheet on both sides. This nested configuration allows the air layer to maintain its thermal insulation function while being protected by the mechanically stronger heat-insulating sheet, addressing both the heat propagation suppression and mechanical strength requirements.
2Strength
If a heat insulator with fiber sheet and silica aerogel is used, then mechanical strength is improved, but heat-insulating performance in high temperature range (500°C or more) is insufficient
Solution Approach 1:
The patent maintains a controlled air layer thickness (0.5-5.0 mm) within the heat-insulating sheet, creating a parameter optimization where the air layer provides superior high-temperature thermal insulation while the surrounding compressible material provides mechanical strength. This parameter control allows the system to achieve both mechanical integrity and high-temperature heat insulation performance.
3Stability of the object's composition
If the density of heat insulator is increased due to compression, then mechanical stability is improved, but thermal conductivity increases and heat-insulating performance is reduced
Solution Approach 1:
The patent employs a composite design where the heat-insulating sheet (compressible material) and air layer work together in a layered structure. The heat-insulating sheet undergoes compression and density increase to provide mechanical stability, while the air layer maintains its low-density, low thermal conductivity properties to provide thermal insulation, thus resolving the contradiction between mechanical stability and heat insulation performance under compression.
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 sheet achieves excellent heat-insulating performance across a wide temperature range from normal use to 500°C or more, maintaining thermal resistance even under increased compressive stress, effectively preventing thermal runaway and ensuring safety.
Implementation Method 1
a first particle layer made from a silica nanoparticle and a second particle layer made from a metal oxide which are stacked in an alternating fashion... the heat-insulating sheet for the battery pack contains a first particle made from a silica nanoparticle... ensuring that an excellent heat-insulating performance can be obtained in a wide temperature range
Data Source
AI summary
A heat-insulating sheet for a battery pack is interposed between battery cells of the battery pack in which the battery cells are connected in series or in parallel. The heat-insulating sheet for the battery pack contains a first particle made from a silica nanoparticle and a second particle made from a metal oxide. A content of the first particle is 60 mass % or more and 95 mass % or less relative to a total mass of the first particle and the second particle.