Battery Pack Structure Using Vaporizing Pad to Block Thermal Runaway
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Solution Overview
Problem
Lithium secondary battery packs face safety concerns due to heat generation and thermal runaway, especially in high-temperature environments, which can lead to ignition or explosion, particularly when multiple batteries are packed closely together.
Innovation Solution
A battery pack design featuring a pack case with a heat-conducting pad that vaporizes or sublimates at high temperatures to create a separation space between cell stack assemblies and the base plate, inhibiting heat propagation and incorporating a support part to maintain the cell stack assemblies at a safe distance from the base plate, thereby preventing ignition or explosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple secondary batteries are packed closely together to increase capacity and output, then the energy density and productivity of the battery pack is improved, but the heat generation accumulates and the risk of thermal runaway increases
Solution Approach 1:
The battery pack is divided into multiple independent modules, each containing a limited number of battery cells (e.g., 2-4 cells per module). These modules are separated by insulating partitions and spaced apart within the pack housing. This segmentation limits the propagation of thermal runaway to individual modules rather than affecting the entire pack, thereby allowing higher overall capacity while controlling heat accumulation risks.
Solution Approach 2:
Thermal management components such as heat sinks, heat dissipation fins, and phase change materials are introduced as intermediary elements between battery cells. These intermediaries actively or passively transfer and dissipate heat generated during charging and discharging, preventing heat accumulation even when multiple cells are packed closely together.
2Device complexity
If battery cells are placed in direct contact with the base plate for structural support, then the device complexity is reduced, but heat dissipation efficiency decreases and thermal runaway risk increases
Solution Approach 1:
The base plate is designed with differentiated regions: contact areas with high thermal conductivity material for efficient heat dissipation, and insulating regions or raised platforms for structural support and electrical isolation. This local quality differentiation allows the base plate to simultaneously serve as a heat sink and a support structure, reducing the need for additional components while improving thermal management.
Solution Approach 2:
The base plate utilizes composite material construction, combining thermally conductive materials (such as aluminum or copper alloys) with thermally insulating materials (such as engineering plastics or ceramic coatings). This composite structure enables selective heat transfer pathways, allowing heat to be dissipated through designated areas while maintaining structural integrity and electrical isolation in other areas.
3Volume of stationary object
If no separation space is provided between battery cells and base plate, then the pack case volume is minimized, but heat propagation to adjacent cells is accelerated during thermal runaway
Solution Approach 1:
Instead of creating horizontal separation spaces between cells that would reduce pack volume, the design utilizes the vertical dimension by incorporating heat dissipation fins, raised support structures, or three-dimensional thermal management components. This allows heat to be dissipated in the vertical direction while maintaining compact horizontal spacing between cells, effectively preventing heat propagation without sacrificing pack density.
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 design enhances heat dissipation during normal operation and effectively suppresses thermal runaway, preventing heat from propagating to adjacent cell stack assemblies, thus improving the safety of the battery pack against ignition or explosion.
Implementation Method 1
a heat-conducting pad between the base plate and the cell stack assembly
Implementation Method 2
heat-conducting pad that phase changes to a gaseous state at a high temperature to form a separation space
Implementation Method 3
heat-conducting pad that phase changes to a gaseous state at a high temperature to form a separation space
Data Source
AI summary
Disclosed herein relates to a battery pack, in which a plurality of cell stack assemblies are housed in a pack case, excluding the frame of a module, thereby providing efficient heat dissipation during normal operation. Additionally, the battery pack has an advantage in enhancing safety against ignition or explosion. In the event of abnormal operation, where any of the cell stack assemblies generates heat or undergoes thermal runaway, the heat from the affected cell stack assembly can be prevented from propagating to adjacent cell stack assemblies by forming a separation space between a base plate and the corresponding cell stack assembly through the vaporization of a heat-conducting pad.