Heat insulation sheet, method for producing same, and secondary battery in which same is used
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Solution Overview
Problem
Conventional heat insulation sheets for secondary batteries have poor adhesiveness, leading to detachment and displacement issues when used between battery cells, which complicates fixation and affects the overall heat insulation performance.
Innovation Solution
A heat insulation sheet comprising a fiber sheet with silica xerogel-filled spaces and dense thermoplastic resin layers on the outer periphery, providing strong adhesion and improved thermal insulation by using glass or carbon fibers and a specific resin layer configuration to enhance flame retardancy and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional heat insulation sheet using non-woven fabric holding silica xerogel is used, then thermal insulation performance is improved, but adhesiveness deteriorates causing detachment and displacement
Solution Approach 1:
The invention combines multiple materials with complementary properties: a non-woven fabric base material for structural support and silica xerogel filling for thermal insulation, creating a composite structure that achieves both excellent heat insulation performance and improved adhesiveness without requiring additional protective sheets
Solution Approach 2:
The invention optimizes specific parameters including silica xerogel filling rate (5-50 wt%), non-woven fabric basis weight (20-100 g/m²), and sheet thickness (0.5-5 mm) to achieve the balance between thermal insulation performance and adhesiveness, allowing the material to meet both requirements simultaneously
2Reliability
If silica xerogel is filled in spaces of fiber sheet, then thermal conductivity is reduced below air level, but structural integrity and fixation difficulty increase
Solution Approach 1:
The invention applies silica xerogel filling selectively to the internal spaces of the non-woven fabric while maintaining the external surface properties suitable for adhesion, creating local differentiation where the interior provides thermal insulation and the exterior provides bonding capability
Solution Approach 2:
The non-woven fabric acts as an intermediary structure that holds the silica xerogel particles while presenting a bonding surface to external components, mediating between the thermal insulation requirement and the fixation requirement
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 ensures strong bonding to protective sheets and frames, preventing displacement and maintaining excellent flame retardancy and thermal insulation properties, even without a protective sheet, thereby enhancing the reliability of secondary batteries by effectively managing heat transfer between cells.
Implementation Method 1
A heat insulation sheet having a thermal conductivity lower than that of air by allowing a non-woven fabric to hold silica xerogel
Implementation Method 2
The resin layer is denser than the fiber sheet and made of thermoplastic resin
Data Source
AI summary
A heat insulation sheet includes a fiber sheet, a resin layer provided on a surface of an outer peripheral portion of the fiber sheet, and a silica xerogel disposed in spaces of the fiber sheet. The fiber sheet includes fibers forming spaces among the fibers. The resin layer is denser than the fiber sheet and made of thermoplastic resin. The silica xerogel is held in the plurality of fibers. This heat insulation sheet is excellent in adhesiveness, and is easily attached to a protective sheet or a frame to be fixed.