Battery Pack Insulation Sheet to Restrain Elastic Edge Swelling
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Solution Overview
Problem
Existing battery packs face issues with uneven repulsive forces due to battery cell expansion, leading to decreased performance and heat insulation properties, particularly when elastic layers or buffer portions are compressed, causing deviations and wobbling between cells.
Innovation Solution
A heat transfer suppression sheet with an elastic sheet and a swelling suppression sheet having a tensile strength of 20 MPa or more, which includes a swelling suppression sheet disposed along the end surface of the elastic sheet to prevent outward swelling and maintain heat insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the elastic layer or buffer portion is designed to be small to protrude into the deformation space or gap, then the expansion of the battery cell can be absorbed, but the repulsive force applied to the battery cell greatly varies depending on the location, shortening the battery lifetime
Solution Approach 1:
The patent applies local quality by designing the buffer portion with non-uniform thickness, where the thickness varies in the planar direction. Specifically, the buffer portion has a first region with a first thickness and a second region with a second thickness different from the first thickness. This gradual thickness variation ensures uniform distribution of repulsive force across the battery cell surface during expansion, preventing localized stress concentrations that would otherwise shorten battery lifetime while maintaining effective expansion absorption.
2Ease of operation
If the buffer portion is disposed in a size equivalent to the size of the main surface of the battery cell, then the buffer portion can be easily compressed and deformed, but the buffer portion swells from the end surface of the heat insulation material, causing deviation or wobbling between the battery cell and heat insulation material
Solution Approach 1:
The patent applies preliminary anti-action by providing a swelling prevention sheet that covers the end surface of the heat insulation material before the buffer portion can swell outward. This swelling prevention sheet restrains the buffer portion from protruding beyond the heat insulation material's end surface, preventing deviation or wobbling between components while still allowing the buffer portion to be compressed and deformed effectively during battery cell expansion.
3Adaptability or versatility
If the buffer portion is largely compressed and deformed, then the expansion can be absorbed, but the thickness is reduced and the heat insulation property decreases
Solution Approach 1:
The patent applies segmentation by dividing the heat insulation structure into distinct functional layers: a heat insulation material layer and a buffer portion layer with different compression characteristics. The buffer portion is designed with specific compression properties that allow it to deform preferentially during battery cell expansion, while the heat insulation material maintains its thickness and insulation properties. This segmentation ensures that expansion absorption does not come at the expense of heat insulation performance.
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 suppresses heat transfer and maintains insulation properties by preventing excessive swelling and wobbling between battery cells, enhancing the performance and longevity of the battery pack.
Implementation Method 1
the swelling suppression sheet has a tensile strength of 20 MPa or more
Implementation Method 2
the elastic layer partially adheres to a surface of a case of a battery cell and includes an elastic protruding portion that is deformed by the expansion of the battery cell
Implementation Method 3
a heat insulation sheet and an elastic layer stacked on a surface of the heat insulation sheet
Data Source
Figure 1(a)~1(b)
Figure 2~3(b)
Figure 4~5
AI summary
To provide a heat transfer suppression sheet capable of suppressing excessive swelling outward of an end surface parallel to a thickness direction of an elastic sheet even in a case where the elastic sheet is pressed in the thickness direction, and capable of suppressing a decrease in heat insulation property due to a reduction in thickness. A heat transfer suppression sheet (10) includes an elastic sheet (11) having a pair of main surfaces (11a) orthogonal to a thickness direction and an end surface (11b) substantially parallel to the thickness direction, and a swelling suppression sheet (12) continuously disposed along at least the end surface (11b). The swelling suppression sheet (12) preferably has a tensile strength of 20 MPa or more and 150 MPa or less.