Viscous Body Layer Vertex Design for Battery Pack Cooling
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Solution Overview
Problem
High surface roughness of the cooled portion in battery pack cell stacks leads to insufficient contact with heat-conducting materials, resulting in lower cooling efficiency, and the use of viscous body layers can be hindered by air entrapment during the manufacturing process.
Innovation Solution
A manufacturing method involving a viscous body layer with a surface configuration that has a vertex with the longest perpendicular distance from the opposing surface, which decreases continuously, ensuring initial contact at the vertex and gradual area increase, reducing air entrapment by pushing air outwards as the cell stack is attached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat-conducting sheet is used to cool the cell stack, then cooling function is provided, but when the surface roughness of the cooled portion is high, sufficient contact area cannot be secured, resulting in lower cooling efficiency
Solution Approach 1:
The patent changes the physical state of the heat-conducting material from a rigid sheet to a viscous body that can be applied in a controlled manner. The viscous body is applied at a temperature and viscosity state that allows it to flow and conform to the surface, then it is cured to form a solid layer that maintains good contact with the rough surface of the cell stack, thereby maintaining cooling efficiency despite surface roughness variations
Solution Approach 2:
The viscous body layer acts as a flexible intermediate layer that can adapt to surface irregularities. Before curing, it remains fluid and can flow into gaps and conform to the rough surface topology, ensuring maximum contact area. After curing, it forms a solid but still conformal layer that maintains the contact quality, effectively compensating for surface roughness issues
2Temperature
If a viscous body layer is used to allow close contact with the cooled portion, then contact area is improved, but air gets entrapped between the viscous body layer and single cells during disposal, resulting in lower cooling efficiency
Solution Approach 1:
The patent applies the viscous body layer to the cooler surface before the cell stack is disposed onto it. This preliminary application allows the viscous body to be in position and in a controlled state before the cell stack contacts it, enabling better control over the air entrapment issue during the subsequent disposal and pressing operations
Solution Approach 2:
Instead of trying to prevent air entrapment by complex mechanisms, the patent inverts the approach by using the pressing operation itself to force air out. The cell stack is pressed onto the viscous body layer, and the pressure applied during this operation forces entrapped air to escape from the interface, thereby reducing air entrapment rather than trying to prevent it beforehand
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 reduces air entrapment between the cell stack and the viscous body layer, enhancing cooling efficiency by maintaining consistent contact and preventing air interference.
Implementation Method 1
a viscous body layer interposed between the cooled portion and the cooler
Data Source
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AI summary
A manufacturing method of a battery pack (60) includes: forming a viscous body layer (64) on a cooler (62) such that an opposed surface (64a) of a viscous body layer (64) facing a cooled portion (61c) of the battery pack (60) has a vertex at which a perpendicular distance from a surface of the viscous body layer (64) opposed to the opposed surface (64a) is longest, and that the perpendicular distance decreases in directions away from the vertex, as seen in a sectional view of the viscous body layer (64) from a long-side direction of the viscous body layer (64); and before hardening of the viscous body layer (64) formed on the cooler (62) is completed, attaching the cell stack (61) to the cooler (62) while pressing the opposed surface (64a) of the viscous body layer (64) with the cooled portion (61c) of the cell stack (61).