Battery Pack Injected with Phase Change Material for Thermal Management
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Solution Overview
Problem
Lithium ion batteries in electric vehicles face performance degradation and safety issues due to temperature fluctuations, leading to heat accumulation and potential thermal runaway, as existing heat-transfer mediums are inefficient under varying vacuum conditions.
Innovation Solution
A battery pack system injected with phase change material, such as hydrofluoroether, is designed with a preset pressure range to achieve phase change, utilizing a thermal conductive layer and cooling fins for effective heat dissipation, and a sealing component to maintain a vacuum state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat-transfer medium is introduced into the battery pack, then heat dissipation is improved, but heat transfer efficiency becomes unstable under varying vacuum conditions
Solution Approach 1:
The patent changes the physical state parameter of the heat transfer medium from liquid to solid-phase-change-material. By selecting a material with a phase change temperature between -50°C to 50°C, the system maintains effective heat transfer across varying vacuum conditions. The phase change process (melting/freezing) provides consistent heat absorption and release regardless of pressure variations, resolving the instability issue.
Solution Approach 2:
The patent utilizes phase transition of the heat transfer medium as the core mechanism. The phase-change-material absorbs heat during melting and releases heat during freezing, providing passive thermal regulation. This phase transition mechanism is inherently more stable under vacuum conditions compared to liquid heat transfer, as it depends primarily on temperature rather than pressure.
2Reliability
If more heat-transfer medium is used to improve heat dissipation, then thermal runaway prevention is improved, but device complexity increases
Solution Approach 1:
The phase-change-material serves multiple functions simultaneously: it acts as a heat transfer medium, a thermal buffer, and a space-filling material. By injecting the material into available void spaces in the battery pack, it maximizes thermal coverage without requiring additional structural components or complex piping systems, thus preventing thermal runaway while maintaining simple packaging.
Solution Approach 2:
The phase-change-material provides self-regulating thermal management without requiring external control systems. When temperature rises, the material automatically absorbs heat through phase change; when temperature drops, it releases heat. This passive self-service mechanism eliminates the need for complex active cooling systems, pumps, or sensors, reducing device complexity while ensuring thermal safety.
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 system maintains optimal temperature within the battery pack, enhancing heat dissipation and preventing thermal runaway by utilizing the phase change material's boiling point within the operational temperature range, ensuring safer and more efficient battery performance.
Implementation Method 1
injected with a phase change material... achieve a phase change
Implementation Method 2
utilizing the phase change material's boiling point within the operational temperature range
Implementation Method 3
utilizing a thermal conductive layer and cooling fins for effective heat dissipation
Implementation Method 4
cooling fins for effective heat dissipation
Implementation Method 5
cooling fins for effective heat dissipation
Data Source
AI summary
The present invention provides a battery pack injected with phase change material, comprising a plurality of battery modules consisting of a plurality of stacked battery cells and a pack case housing the battery modules. The battery pack is hermetic, and injected with hydrofluoroether. The pressure in the pack case is between −0.09 MPa and −0.01 MPa.