Compressible Cell Insulation Assembly for Thermal Runaway Delay
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Solution Overview
Problem
High-voltage storage devices face challenges in maintaining thermal insulation between adjacent cells as they age, leading to increased heat conduction and potential thermal runaway due to cell bulging, which reduces the air gap and corresponding thermal insulation.
Innovation Solution
A cell assembly with thermally insulating and compressible insulation bodies arranged between cells, featuring a rigidity curve with specific compression value sections to maintain a minimum specific heat resistance of 5 m·K/W, absorbing pressures from cell bulging and fixing, thereby delaying or preventing thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air gap is used for thermal insulation between cells, then thermal insulation is provided, but the insulation effectiveness decreases with cell bulging during aging
Solution Approach 1:
The patent applies parameter changes by selecting insulation materials with specific mechanical and thermal properties. The insulation material is chosen to have compressibility to accommodate cell bulging while maintaining minimum thickness for thermal insulation. The material parameters (compressive modulus, thermal conductivity) are optimized to maintain insulation effectiveness throughout the service life despite dimensional changes in the cells.
Solution Approach 2:
The patent implements beforehand cushioning by pre-compressing the insulation material during assembly to account for future cell bulging. The insulation material is selected and positioned to provide adequate thermal insulation from the beginning, with its compressible nature allowing it to absorb future expansion of cells without losing insulation effectiveness. This prevents thermal runaway by maintaining thermal barriers even after aging.
2Manufacturing precision
If cells are compressed to specified length during production, then tolerance variations are equalized, but cell bulging space is reduced
Solution Approach 1:
The patent applies local quality by providing different functional zones within the cell assembly. The insulation material is positioned specifically in regions where thermal insulation is most critical, while maintaining overall compression for tolerance equalization. This localized insulation approach ensures thermal safety in key areas without preventing necessary compression for manufacturing precision.
Solution Approach 2:
The patent uses composite materials combining insulation properties with compressibility. The insulation material is not merely air gaps but solid or semi-solid materials that provide both thermal insulation and mechanical compliance. This composite approach allows the material to simultaneously equalize tolerances through compression while maintaining thermal barriers to prevent runaway.
3Quantity of substance
If insulation material thickness is reduced due to cell bulging, then cell assembly density increases, but thermal insulation performance deteriorates
Solution Approach 1:
The patent applies parameter changes by selecting insulation materials with optimized thermal conductivity and compressibility parameters. The material is chosen to maintain adequate thermal resistance even when compressed to thin sections. The insulation material's thermal properties are specifically selected to ensure that even reduced thickness maintains sufficient insulation performance to prevent thermal runaway.
Solution Approach 2:
The patent implements beforehand cushioning by pre-positioning insulation material with sufficient initial thickness and compressibility to accommodate future cell bulging. The insulation material is selected and installed to maintain minimum effective thickness throughout the product lifecycle, ensuring thermal insulation performance is preserved even as cells expand during aging and energy density may vary.
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 effectively reduces heat conduction between adjacent cells, even at advanced ages, delaying or preventing thermal runaway and enhancing the safety and energy density of high-voltage storage devices.
Implementation Method 1
The first insulation body is configured to absorb a pressure exerted by the lateral surfaces of the two cells on lateral surfaces of the first insulation body respectively opposite thereto, where the compression is along a compression direction
Implementation Method 2
The specific compression value corresponds to a thickness of the first insulation body along the compression direction at which the insulation body has a specific heat resistance of at least 5 m·K/W along the compression direction
Data Source
AI summary
A cell assembly for an electrochemical energy storage device has: two cells for electrochemically storing electric energy; and a first insulating body for thermally insulating the two cells from each other. The insulating body is arranged between the cells in an intermediate space delimited by a respective lateral surface of each of the two cells and is configured to absorb pressure exerted by the lateral surfaces of the two cells on lateral surfaces of the first insulation body, where compression occurs along a compression direction. The insulating body includes a first thermally insulating and compressible fiber material and has a rigidity as a function of compression, where a value curve of the rigidity has a first compression value section and a second compression value section adjoining the first compression value section. A cell module has a cell assembly and a high-voltage storage device has a cell module as described herein.