Battery Pack Venting and Restraint for Cell Expansion Control
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Solution Overview
Problem
Power storage devices in vehicles face issues with upward expansion of power storage cells due to heat generation, which can lead to heating of the vehicle interior and potential deformation of the floor panel.
Innovation Solution
A power storage device configuration that includes a safety valve in the lower surface, an exhaust path below the support portion, a cooler to cool the discharged gas, and a plate-shaped member or adhesive to suppress upward expansion of the cells, thereby preventing heat and gas transfer to the vehicle interior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If power storage cells are disposed inside the accommodation case without additional restraint structures, then the device complexity is reduced, but the power storage cells may expand upward and exert influence on the vehicle interior
Solution Approach 1:
A flexible restraint band is disposed above the power storage stack, extending in the width direction along the central portion of the upper surfaces of the power storage cells. The restraint band is flexible enough to accommodate cell expansion while providing restraint force to prevent excessive upward expansion that would affect the vehicle interior.
Solution Approach 2:
The restraint band serves multiple functions: it restrains upward expansion of power storage cells, provides structural support to the power storage stack, and acts as a thermal barrier to prevent heat transfer from discharged gas to the vehicle interior.
2Object-affected harmful factors
If the safety valve is disposed in the lower surface of the power storage cell, then heat transfer to the vehicle interior is suppressed, but the device complexity increases due to additional exhaust path structures
Solution Approach 1:
The exhaust path is configured to extend in the width direction (lateral dimension) rather than vertically upward. By providing the exhaust path below the support portion and communicating with the space below the safety valve, the design redirects hot gas laterally away from the vehicle interior, utilizing horizontal space to solve a vertical heat transfer problem.
Solution Approach 2:
The exhaust path acts as an intermediary channel that captures hot gas discharged from the safety valve and redirects it laterally through the cooler region, preventing direct contact with the vehicle interior while maintaining the simplicity of the safety valve placement in the lower surface.
3Temperature
If a cooler is disposed below the power storage stack, then heat from discharged gas is reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The cooler is integrated with the exhaust path structure, forming a unified cooling and exhaust system. The cooler is disposed below the power storage stack and communicates with the exhaust path, allowing hot gas to be cooled as it travels through the exhaust path laterally, combining cooling and exhaust functions in a single integrated structure.
4Stability of the object's composition
If the restraint band extends along the central portion of the upper surface of the power storage cells, then upward expansion is suppressed, but the manufacturing precision requirements increase
Solution Approach 1:
The restraint band is positioned to extend along the central portion of the upper surfaces of the power storage cells in the width direction, providing restraint force where it is most needed to prevent upward expansion. This localized positioning focuses the restraint function on the critical central region while reducing the overall complexity compared to full-coverage restraint structures.
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 solution effectively suppresses upward expansion and heat transfer from power storage cells, maintaining the vehicle interior's integrity and reducing deformation of the floor panel.
Implementation Method 1
a cooler that cools the power storage stack, the cooler being disposed below the power storage stack
Implementation Method 2
a safety valve being disposed in the lower surface... an exhaust path provided below the support portion and provided to be able to communicate with a space located below the safety valve
Data Source
AI summary
A power storage device includes: a power storage stack including a plurality of power storage cells each having a lower surface and an upper surface, a safety valve being disposed in the lower surface; a support portion that supports the power storage stack from below; an exhaust path provided below the support portion and provided to be able to communicate with a space located directly below the safety valve; a cooler that cools the power storage stack, the cooler being disposed below the power storage stack; and a plate-shaped member disposed above the power storage stack and facing the upper surface of each of the power storage cells.