Battery Stack Output Terminal Layout Against Capillary Water Ingress
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Solution Overview
Problem
Power supply devices for electric vehicles and power storage systems face challenges in preventing water ingress due to capillary phenomena, leading to potential short circuits and safety hazards, especially when dew condensation occurs.
Innovation Solution
The design incorporates a power supply device with a battery stack configuration that includes spacers, end plates, and fastening members, featuring wide regions in critical gaps to inhibit capillary phenomena, along with a terminal cover and sloped surfaces to guide moisture away from the output terminal, ensuring that the path from the lower plate to the output terminal is wide enough to prevent liquid junctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a high sealability outer covering case is used to prevent water entry, then water ingress is reduced, but dew condensation water still accumulates inside due to temperature differences
Solution Approach 1:
The patent extracts the harmful condensation water from the enclosed space by providing drainage paths that lead water outward from the battery stack region, preventing accumulation while maintaining the sealed enclosure
Solution Approach 2:
The patent introduces drainage paths and wick structures that create three-dimensional water removal pathways, transitioning from a two-dimensional sealed surface to a multi-dimensional water management system that actively removes condensation
2Quantity of substance
If battery cells are stacked closely to increase power density, then energy density is improved, but capillary phenomenon causes water to enter gaps leading to liquid junction
Solution Approach 1:
The patent applies different properties to different regions: hydrophobic coatings are applied locally to critical surfaces where water contact occurs, and wick structures are positioned specifically in gap regions to prevent capillary action while maintaining close stacking
Solution Approach 2:
The patent introduces intermediary structures such as hydrophobic barrier layers and wick materials between battery cells that mediate the interaction between water and the battery stack, preventing direct water contact and capillary infiltration while allowing close stacking
3Reliability
If insulation structures are added to prevent liquid junction, then safety is improved, but device complexity increases
Solution Approach 1:
The patent designs components with multiple functions: the outer covering case not only provides structural enclosure but also serves as a condensation collection surface with integrated drainage paths; fastening members not only secure components but also incorporate hydrophobic barriers and wick structures for water management
Solution Approach 2:
The patent merges water management functions into existing structural components rather than adding separate systems: drainage paths are integrated into the case structure, hydrophobic coatings are applied to fastening surfaces, and wick structures are incorporated into the stacking arrangement
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
This configuration effectively suppresses capillary phenomena, preventing liquid junctions and enhancing safety by ensuring that water cannot easily enter and cause unintended conduction between components, thereby improving the reliability and safety of the power supply device.
Implementation Method 1
one or more wide regions expanded to be intervals at which a capillary phenomenon does not occur are formed in a path of a gap from the lower plate or the fastening members to the output terminal
Implementation Method 2
sloped surfaces to guide moisture away from the output terminal
Data Source
AI summary
The power supply device including, in a battery stack, a spacer interposed between adjacent battery cells, end plates that press end surfaces of the battery stack, a plurality of fastening members each formed into a plate shape extending in a stacking direction of the plurality of battery cells, the fastening members being disposed on opposite side surfaces of the battery stack and fastening end plates to each other, an output terminal that connects the plurality of battery cells in series or in parallel and outputs electric power, and a lower plate that is made of metal and covers a lower surface of the battery stack, wherein the output terminal is disposed near an upper surface side of the battery stack, and one or more wide regions expanded to be intervals at which a capillary phenomenon does not occur are formed in a path of a gap from the lower plate or the plurality of fastening members to the output terminal