Battery Thermal Insulation Layer Balancing Heat Resistance and Strength
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Solution Overview
Problem
Current thermal insulation materials for nonaqueous electrolyte secondary batteries lack a balance between thermal insulation properties and mechanical strength, making them inadequate for preventing thermal runaway in battery cells.
Innovation Solution
A thermal insulation material comprising hydrophilic fumed silica and inorganic fibers with specific fiber length and density distributions, optimized to achieve both excellent thermal insulation and mechanical strength, is developed. The material's structure includes a thermal insulation layer with a density between 0.2 and 0.5 g/cm3, and cumulative fiber length proportions calculated using a specific formula to ensure effective insulation and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal insulation material uses conventional structure without specific fiber length control, then thermal insulation property is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the fiber length of inorganic fibers within the range of 6 mm or longer and shorter than 35 mm, and by controlling the void area ratio on the surface to be larger than 0% and smaller than 22%. These specific parameter ranges optimize both thermal insulation performance and mechanical strength, resolving the contradiction between the two properties.
Solution Approach 2:
The patent uses a composite material structure combining hydrophilic fumed silica and inorganic fibers with specific length characteristics. This composite approach allows the material to achieve both excellent thermal insulation properties and sufficient mechanical strength, as the combination of different materials with controlled parameters creates synergistic effects that resolve the contradiction between insulation and strength.
2Temperature
If thermal insulation material increases void space for insulation, then thermal insulation property is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent utilizes porous material structure by controlling the void area on the surface to be larger than 0% and smaller than 22% of the total surface area. This controlled porosity provides thermal insulation benefits while maintaining sufficient mechanical strength through the optimized void distribution and fiber network structure.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the void area ratio on the surface to be within the specific range of larger than 0% and smaller than 22%. This parameter optimization allows the material to achieve both thermal insulation performance and mechanical strength by balancing the void space with the fiber network 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 material provides enhanced thermal insulation and mechanical strength, effectively preventing thermal runaway in battery cells by managing fiber length and density within the thermal insulation layer, thereby ensuring both thermal resistance and structural integrity.
Implementation Method 1
a thermal insulation material placed between battery cells in order to avoid contact between adjoining battery cells and thermally insulate the battery cells from each other
Data Source
AI summary
An object is to provide a thermal insulation material excellent in both thermal insulation property and mechanical strength. A thermal insulation material includes a thermal insulation layer containing silicon dioxide particles and inorganic fibers, and is excellent in both thermal insulation property and mechanical strength, because density ρ [g/cm3] of thermal insulation layer, and a cumulative proportion R1 for a fiber length of >0 mm and <4 mm regarding inorganic fibers contained in the thermal insulation layer and a cumulative proportion R2 for a fiber length of ≥3 mm and <30 mm regarding inorganic fibers contained in the thermal insulation layer satisfy a relational expression (I) below, R1 and R2 being calculated according to predetermined calculation formulae when the inorganic fibers contained in the thermal insulation layer are summed up based on predetermined conditions.0.23R1+0.24<ρ≤-0.11R2+0.53Relational expression (I)