Battery Partition Member With Switchable Thermal Resistance
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Solution Overview
Problem
Existing partition members in battery assemblies lack sufficient pressure resistance and fail to properly switch thermal resistance before and after a certain temperature, which is crucial for managing abnormal temperature increases in secondary batteries.
Innovation Solution
A partition member comprising a thermal insulating material capable of retaining a liquid, housed within an external package, with a specific relationship between the internal space area of the package, the size and thickness of the thermal insulating material, and the volume of the liquid, ensuring high opening temperature and thermal resistance after opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a partition member with a bag containing coolant is used between single cells, then thermal conduction from damaged cells is improved, but pressure resistance is insufficient
Solution Approach 1:
The partition member uses a composite structure combining a heat-resistant porous material (providing pressure resistance) with a coolant-containing bag (providing thermal conduction). This composite approach allows both functions to coexist: the porous material structure withstands battery assembly pressure while the coolant bag efficiently conducts heat away from damaged cells.
2Temperature
If the thermal resistance is kept low to suppress temperature increase, then thermal conduction is improved, but the ability to suppress chain spread during abnormal temperature events is reduced
Solution Approach 1:
The partition member dynamically changes its thermal resistance based on temperature conditions. At normal operating temperatures, the coolant remains liquid and maintains low thermal resistance for efficient heat dissipation. When abnormal high temperatures are detected, the coolant evaporates or the material structure changes, causing thermal resistance to increase and automatically suppressing heat transfer to adjacent cells, thus preventing chain spread.
Solution Approach 2:
The partition member utilizes parameter changes in the coolant (phase change from liquid to vapor) or in the porous material structure in response to temperature changes. This parameter change allows the system to automatically adjust thermal resistance without external control, maintaining low resistance during normal operation and high resistance during abnormal conditions.
3Strength
If the opening temperature is increased to maintain partition integrity, then pressure resistance is improved, but the ability to switch thermal resistance properly is reduced
Solution Approach 1:
The partition member employs local quality differentiation where different regions or components have different thermal properties. The porous material structure provides high temperature stability and pressure resistance throughout, while the coolant-containing regions provide the thermal resistance switching function. This local differentiation allows the system to maintain both high opening temperature capability and proper thermal resistance switching.
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 partition member achieves a high opening temperature and significant thermal resistance switching, effectively suppressing thermal conduction to adjacent cells during abnormal temperature events while maintaining low thermal resistance before opening.
Implementation Method 1
heat generated in the adjacent single cell can be efficiently transferred to the nearby single cells
Implementation Method 2
at the opening temperature or more, the liquid is evaporated, and a high thermal resistance is exhibited by the remaining thermal insulating material
Implementation Method 3
the temperature at which the vapor pressure of the liquid exceeds the breakdown strength of the external package
Implementation Method 4
a thermal insulating material capable of retaining a liquid
Implementation Method 5
a thermal insulating material capable of retaining a liquid
Data Source
AI summary
A partition member having a thermal insulating material capable of retaining a liquid, and an external package housing the thermal insulating material and the liquid, having a particular set relationship among the internal space area of the external package, the size of the thermal insulating material, the thickness of the thermal insulating material, and the volume of the liquid.