Foldable Battery Cell Cover for Thermal Insulation and Venting
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Solution Overview
Problem
Existing battery cells are prone to thermal runaway, which can lead to destructive events such as fire and explosion due to exothermic reactions, and current insulation materials fail to provide adequate protection at high temperatures.
Innovation Solution
A battery cell design featuring a protective cover with a heat resistance of at least 800°C that covers the terminal side and side walls of the battery cell housing, which is foldable to provide comprehensive thermal protection and can break to vent gases during thermal runaway, while also acting as an electrical insulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulation materials are used in battery cells, then the device complexity is low and ease of manufacture is high, but the reliability is insufficient due to thermal runaway susceptibility at high temperatures
Solution Approach 1:
The protective cover is made from a composite material comprising aramid fibers and polymer matrix, providing high heat resistance (withstanding temperatures up to 800°C) and electrical insulation properties. This composite structure enables the cover to prevent thermal runaway while maintaining structural integrity during exothermic reactions, directly resolving the reliability issue without excessive complexity
Solution Approach 2:
The protective cover is designed with a segmented structure including a cover body, side walls extending from the cover body, and optional flaps that can fold to cover additional surfaces. This segmentation allows the single component to protect multiple surfaces (top, sides, and potentially bottom) of the battery cell, providing comprehensive thermal protection while remaining manufacturable as a unified part
2Reliability
If the protective cover completely seals the battery cell housing, then thermal protection is maximized, but the ability to vent gases during thermal runaway is reduced
Solution Approach 1:
The protective cover acts as an intermediary barrier between the battery cell interior and external environment. It is positioned to cover the top and extend down the sides, creating a protective envelope that blocks external heat sources and contains thermal runaway effects while allowing controlled gas venting through the venting valve, thus mediating between thermal protection and pressure relief needs
Solution Approach 2:
The protective cover provides different functional qualities at different locations: the cover body and side walls provide continuous thermal protection and electrical insulation, while the venting valve area maintains localized opening for gas escape. This local differentiation of quality (sealed vs. vented regions) resolves the contradiction between complete sealing for thermal protection and gas venting capability
3Weight of moving object
If aluminum framework is used for mechanical integration, then the weight is reduced, but the heat resistance is insufficient for high-temperature thermal runaway conditions
Solution Approach 1:
The protective cover serves as a thermal intermediary layer positioned between the battery cell components and the external aluminum framework. This cover, with its high heat resistance composite material, blocks heat transfer from the aluminum framework to the battery cell during thermal runaway, while the aluminum framework itself remains lightweight for structural support
Solution Approach 2:
The protective cover provides localized high-temperature protection at the battery cell level, while the aluminum framework provides lightweight structural support at the system level. Each component has optimized local quality: the cover for heat resistance where thermal runaway occurs, and the framework for weight reduction in structural applications
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 protective cover effectively reduces the incidence of thermal runaway by blocking heat transfer and preventing electrical short circuits, enhancing safety and reducing the risk of fire and explosion.
Implementation Method 1
The protective cover has a heat resistance of at least 800°C and is configured to cover the terminal side and side walls of the battery cell housing
Implementation Method 2
the protective cover... acting as an electrical insulator
Implementation Method 3
the protective cover is configured to break to vent gases during thermal runaway
Data Source
Figure 1~2
Figure 3~4
AI summary
The present disclosure refers to battery cell (10). The battery cell (10) includes a battery cell housing (12) and a protective cover (20). The battery cell housing (12) has a pair of electrode terminals (14) and a venting valve (16) disposed on a terminal side (18). The protective cover (20) is configured to cover the terminal side (18) and to be folded to further cover two opposite side walls (22) of the battery cell housing (12) extending from the terminal side (18) to an extent of at least 25 percent of the area of each opposite side wall (22). Further, the protective cover (20) has a heat resistance of at least 800°C.