Battery Cell Separator Structure for Swelling-Resistant Insulation
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Solution Overview
Problem
Existing cell-accommodating members in vehicle-mounted battery modules suffer from deteriorating electrical and thermal insulation properties due to deformation of secondary battery cells, leading to reduced insulation distances and increased heat transfer.
Innovation Solution
A cell-accommodating member comprising a housing, inter-cell separators with electrical and thermal insulation properties, and elastic members that deform more than the separators to maintain consistent insulation distances and heat transfer distances despite cell deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the separator is made flexible to absorb cell deformation, then the ability to accommodate cell bulging is improved, but the electrical insulation properties and thermal insulation properties deteriorate due to reduced insulation distance
Solution Approach 1:
The separator is divided into a first separator and a second separator arranged in series between adjacent cells. The first separator provides electrical and thermal insulation, while the second separator absorbs cell deformation. This segmentation allows each component to specialize in one function, resolving the contradiction between maintaining insulation properties and absorbing deformation.
Solution Approach 2:
The second separator acts as an intermediary element between the first separator and the cell. It absorbs the deformation from the cell before it reaches the first separator, protecting the first separator from direct mechanical stress while maintaining the insulation function. This intermediary structure allows the system to simultaneously achieve deformation absorption and insulation property maintenance.
2Stability of the object's composition
If the separator shrinks to follow cell deformation, then the flexibility to accommodate bulging is improved, but the insulation distance between cells becomes shorter
Solution Approach 1:
The separator system is segmented into two distinct components: the first separator that maintains its dimensional stability to preserve insulation distance, and the second separator that is designed to shrink and expand with cell deformation. This segmentation resolves the contradiction by assigning different mechanical behaviors to different parts of the separator system.
Solution Approach 2:
Different regions of the separator system are given different mechanical properties. The first separator has low elasticity to maintain insulation distance, while the second separator has high elasticity to follow cell deformation. This local differentiation of material properties allows the system to simultaneously achieve both flexibility and maintained insulation distance.
3Device complexity
If a single separator performs both insulation and deformation absorption, then the device complexity is reduced, but the insulation properties become unstable under cell deformation
Solution Approach 1:
The separator function is segmented into two distinct separators with different material properties and functions. The first separator focuses on insulation while the second focuses on deformation absorption. This functional segmentation resolves the contradiction by allowing each component to optimize for its specific function rather than compromising performance across both functions.
Solution Approach 2:
While the system uses two separators, the first separator can be designed with a structure that provides both insulation and some deformation tolerance, while the second separator specializes in deformation absorption. This multi-functional design approach allows the system to maintain insulation stability while accommodating cell deformation through coordinated action of the two separators.
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
Stably ensures electrical and thermal insulation properties by absorbing cell deformations, preventing changes in insulation and heat transfer distances, and facilitating efficient cell arrangement and cooling.
Implementation Method 1
an elastic member, disposed on the inter-cell separator, elastically contacting the cell adjacent in the stacking direction, and being more elastically deformable following deformation of the cell than the inter-cell separator
Implementation Method 2
the separator possesses electrical insulation properties to ensure insulation between a pair of adjacent secondary battery cells and to suppress a short circuit
Implementation Method 3
the separator possesses thermal insulation properties to suppress heat transfer between the pair of secondary battery cells adjacent to each other and to suppress the chain reaction of thermal runaway
Data Source
AI summary
A stacked body (8) of a plurality of cells (80) for a secondary battery is accommodated in a cell-accommodating member (1). The cell-accommodating member (1) comprises: a housing (2) that has an interior space (20) in which the stacked body (8) is accommodated; inter-cell separators (3) that are arranged in the interior space (20) and are interposed between any pair of cells (80) that are adjacent to each other in the stacking direction, the inter-cell separators having electric insulation properties and thermal insulation properties; and elastic members (4) that are arranged at the inter-cell separators (3) and are in elastic contact with adjacent cells (80) in the stacking direction, the elastic members being more readily deformed in accordance with deformation of the cells (80) than the inter-cell separators (3).