Battery Pack Thermal Management via Phase Change Layer
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Solution Overview
Problem
High-output, large-capacity battery packs face issues with temperature differences between unit cells leading to degradation, increased size due to conventional cooling systems, and potential damage from foreign matter, especially in varying environmental conditions.
Innovation Solution
A dual temperature-controlling system using a heat transfer medium flowing through gaps between unit cells and a phase transformation layer on each unit cell to regulate overall and individual cell temperatures, minimizing temperature differences and protecting against foreign matter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional coolant-flow cooling system is used to cool the battery pack, then the overall temperature of the battery pack is reduced, but the temperature difference between unit cells becomes very large
Solution Approach 1:
The cooling system is segmented into two independent subsystems: (1) a coolant-flow system that circulates coolant through channels to remove heat from the battery pack as a whole, and (2) a phase-change material system where phase-change materials are embedded in each unit cell to provide localized temperature regulation. This segmentation allows each subsystem to address different aspects of thermal management independently, preventing the temperature uniformity problems that arise in conventional unified cooling systems.
Solution Approach 2:
Phase-change materials are individually embedded in each unit cell or battery module, providing localized thermal regulation tailored to the specific heat generation characteristics of each cell. This local quality approach ensures that each unit cell maintains its temperature within the optimal range independently, addressing the temperature uniformity issue at the cell level rather than relying on uniform coolant distribution across the entire pack.
2Temperature
If a conventional coolant-flow cooling system is used, then heat is removed from the battery pack, but the size of the battery pack increases
Solution Approach 1:
The cooling function is merged with the structural components of the battery pack. Phase-change materials are embedded directly within the unit cells or battery modules, combining the energy storage function with the thermal management function. This integration eliminates the need for separate, bulky cooling chambers or extensive coolant channels, thereby reducing the overall battery pack volume while maintaining effective heat removal capability.
Solution Approach 2:
Phase-change materials are utilized to absorb and store heat through phase transition (e.g., solid-liquid transition) within the unit cells. This approach provides high heat removal capacity without requiring large volumes of coolant or complex cooling infrastructure, as the phase-change process occurs within the compact structure of the battery cells themselves.
3Temperature
If unit cells are cooled using a coolant-flow system, then heat is removed, but foreign matter can damage the unit cells
Solution Approach 1:
Phase-change materials serve as an intermediary thermal management mechanism that does not require direct contact with external coolant or exposure to foreign matter. The phase-change materials are sealed within the unit cells, creating a barrier that prevents foreign matter from reaching and damaging the sensitive battery components while still providing effective heat absorption and temperature control through the phase transition process.
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 effectively maintains unit cell temperatures within an optimal range, reduces battery pack size, and prevents damage from foreign matter, ensuring safe and efficient operation.
Implementation Method 1
a heat transfer medium flows through gaps defined between unit cells of the battery pack for controlling an overall temperature of the battery pack
Implementation Method 2
each unit cell is provided at an outer surface of the unit cell, at which the heat transfer medium is brought into contact with the unit cell, with a layer comprising a phase transformation material
Data Source
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AI summary
Disclosed herein is a middle- or large-sized battery pack including a plurality of unit cells electrically connected with each other, wherein the battery pack is constructed in a structure in which a heat transfer medium flows through gaps defined between the unit cells for controlling the overall temperature of the battery pack to be within a predetermined temperature range for the optimum operation of the battery pack, and each unit cell is provided at the outer surface thereof, at which the heat transfer medium is brought into contact with each unit cell, with a layer containing a phase transformation material ('phase transformation layer') for minimizing individual temperature difference between the unit cells. The present invention has the effect of controlling the overall temperature of the battery pack and individually controlling the temperatures of unit cells constituting the battery pack. Also, the present invention has the effect of restraining the abrupt change in temperature of the unit cells, when the battery pack is not in operation or when the external environment abruptly changes, thereby preventing the degradation of the unit cells. Furthermore, the present invention has the effect of minimizing damage to the unit cells due to foreign matter when the foreign matter is brought into contact with the unit cells. In addition, the present invention has the effect of reducing the overall temperature difference of the battery pack and manufacturing a middle- or large-sized battery pack having a compact structure.