Segmented Heatsink Assembly for Thermal Expansion Control
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Solution Overview
Problem
The deformation of heatsinks due to thermal expansion causes inhomogeneous stresses on press-pack power devices, leading to poor electrical contact and potential failure of power converters.
Innovation Solution
A heatsink design with independent cooling and support pieces allowing relative movement to accommodate thermal expansion, featuring coolant inlets and outlets on the same side surface and centring means for assembly, ensuring stable electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a liquid cooled heatsink is made of one piece with cooling channels, then cooling efficiency is improved, but thermal expansion causes deformation and inhomogeneous stresses that deteriorate electrical contact
Solution Approach 1:
The heatsink is divided into three separate components: a support piece, a first cooling piece, and a second cooling piece. These segments are arranged in a stackable configuration that allows independent thermal expansion of each component while maintaining overall structural integrity and electrical contact stability.
Solution Approach 2:
The patent introduces a dynamic adjustment mechanism with adjustable means that allow the cooling pieces to be positioned at different distances from the press-pack power device. This enables the system to adapt to thermal expansion and contraction, maintaining optimal electrical contact under varying temperature conditions.
2Force
If heatsinks are compacted to apply homogeneous pressure, then contact pressure is improved, but thermal expansion generates excessive inhomogeneous stresses on IGBTs
Solution Approach 1:
Dividing the heatsink into multiple stackable cooling pieces reduces the overall stress on IGBTs by distributing the thermal expansion across separate components rather than a single monolithic structure.
Solution Approach 2:
The adjustable means enable dynamic control of the distance between cooling pieces and the press-pack power device, allowing the system to compensate for thermal expansion and maintain homogeneous contact pressure without generating excessive inhomogeneous stresses.
3Stability of the object's composition
If heatsinks are made as single-piece massive structures, then structural stability is improved, but thermal expansion causes banana-shaped deformation
Solution Approach 1:
The single-piece massive structure is segmented into multiple separate cooling pieces that can be stacked. Each piece is smaller and less prone to deformation, and the stackable configuration allows for more uniform thermal distribution and reduced banana-shaped deformation.
Solution Approach 2:
The patent employs thin-walled cooling pieces with optimized geometry that are less susceptible to thermal deformation while maintaining structural stability through the stackable configuration and support piece design.
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
Enhances the durability and electrical contact of power converters by mitigating thermal expansion-induced stresses, thereby extending device life and improving power quality.
Implementation Method 1
a first cooling piece and a support piece... the first surface of the first cooling piece being configured to be in direct contact with one of the upper and lower contact surfaces
Implementation Method 2
an inlet configured to receive a coolant and an outlet configured to exhaust the coolant
Implementation Method 3
As the temperature of the first and second surfaces are different, a temperature gradient is generated for the heatsinks at the ends of the stack. These heatsinks are subjected to thermal expansion so that the heatsinks at the ends of the stack are deformed according to a 'banana shape'.
Data Source
Figure 1
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Figure 5~6
AI summary
The heatsink (16, 17, 18, 19, 20) for cooling at least one electronic device package (12, 13, 14, 15) having an upper contact surface (12a, 13a, 14a, 15a) and a lower contact surface (12b, 13b, 14b, 15b) is proposed. The heat sink comprises a first cooling piece (24) and a support piece (23). The support piece (23) and the first cooling piece (24) are two independent pieces so that the interface between the first surface of the support piece and the second surface of the first cooling piece allows a relative movement between the support piece and the first cooling piece along a direction parallel to the interface between the first cooling piece and the support piece.