Foamable Heat Insulating Layer for Battery Pack Thermal Management
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Solution Overview
Problem
Conventional battery packs face challenges in maintaining energy density due to the need for thick heat insulating layers to prevent temperature spread, which increases the size and decreases energy density when abnormal heat generation occurs.
Innovation Solution
A battery pack design featuring a thin foamable layer that expands to form a thicker foam heat insulating layer at elevated temperatures, utilizing inorganic materials like silicates of alkali metals, which discharge crystal water to create air bubbles for improved heat insulation, and a block layer to prevent leakage and maintain heat insulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thick heat insulating layer is used to prevent temperature spread during abnormal heat generation, then heat insulation performance is improved, but the size of the battery pack increases and energy density decreases
Solution Approach 1:
The heat insulating layer transitions from a thin compressed state during normal operation to a thick expanded state during abnormal heat generation. The foamable layer contains gas bubbles that expand when heated, dynamically adjusting the insulation thickness based on operational conditions. This resolves the contradiction by providing thick insulation only when needed, maintaining compact size during normal use.
Solution Approach 2:
The physical state and volume of the heat insulating layer change based on temperature parameters. At normal temperatures, the layer remains compressed and thin. When temperature exceeds a threshold during abnormal heat generation, the foamable layer expands significantly, increasing insulation thickness. This parameter-based transformation allows the system to adapt insulation performance to operational conditions.
2Temperature
If a thick heat insulating layer is used to prevent temperature spread, then heat insulation performance is improved, but energy density decreases
Solution Approach 1:
The heat insulating layer dynamically adjusts its thickness based on thermal conditions. During normal operation, the layer remains thin, maximizing the volume available for energy-storing battery cells and maintaining high energy density. During abnormal heat generation, the layer expands to provide necessary insulation, protecting against thermal runaway without permanently reducing energy density.
Solution Approach 2:
The foamable layer is pre-positioned in a compressed state within the battery pack structure. When abnormal heat generation occurs, it automatically expands to fill the available space and provide insulation. This preliminary positioning allows the system to maintain high energy density under normal conditions while ensuring protection is available when needed.
3Volume of moving object
If a thin heat insulating layer is used to maintain compact size, then battery pack size is reduced, but heat insulation performance deteriorates during abnormal heat generation
Solution Approach 1:
The heat insulating layer's thickness parameter changes in response to temperature conditions. During normal operation, the layer remains thin to maintain compact battery pack size. When temperature exceeds a threshold during abnormal heat generation, the foamable layer expands significantly, increasing thickness to provide adequate insulation performance.
Solution Approach 2:
The system transitions from a static thin insulation layer to a dynamic adaptive insulation system. The foamable layer's volume and insulation capability dynamically adjust based on thermal conditions, providing thin insulation during normal operation and thick insulation during abnormal heat generation, thus resolving the contradiction between size and performance.
4Temperature
If conventional heat insulating materials are used, then heat insulation is provided, but the materials do not absorb heat effectively during malfunction
Solution Approach 1:
The foamable layer utilizes phase transition during abnormal heat generation. When heated beyond a threshold temperature, the trapped gas bubbles within the foamable layer expand, causing a volume phase transition. This expansion process absorbs heat energy, providing both insulation and active heat absorption to mitigate thermal runaway.
Solution Approach 2:
The invention converts the harmful effect of heat generation during malfunction into a beneficial heat absorption mechanism. The foamable layer's expansion process, triggered by abnormal heat, actively absorbs excess heat energy while providing insulation. This transforms the thermal hazard into a protective heat-sinking mechanism that limits temperature rise.
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 allows for a thin heat insulating layer in normal conditions while providing high heat insulation during malfunctions, maintaining energy density and preventing temperature increases and leakage, thus enhancing the reliability and safety of the battery pack.
Implementation Method 1
proposed is a method for introducing a polymeric material in the battery pack to utilize melting latent heat generated when the polymeric material melts
Implementation Method 2
When each of the magnesium hydroxide and the aluminum hydroxide is heated, it absorbs ambient heat and discharges water (H2O). Therefore, combustion heat is reduced by this heat absorbing action.
Implementation Method 3
A battery pack design featuring a thin foamable layer that expands to form a thicker foam heat insulating layer at elevated temperatures
Data Source
Figure 1
Figure 2
AI summary
A battery pack 1 of the present invention includes: a secondary battery 2; a molded body 11 configured to store therein the secondary battery; and a foamable layer 12 provided between the secondary battery and an inner surface of the molded body and configured to foam at a predetermined temperature or higher to form a foam heat insulating layer. With this, a heat insulating layer contained in the battery pack is thin in a normal state where the battery is not generating heat, and the heat insulating layer exerts a high heat insulating effect at the time of malfunction to suppress the temperature increase of a surface of the battery pack.