Grooved Heat Dissipation Sheet for Grease Pump-Out Suppression
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Solution Overview
Problem
Heat-radiating sheets fail to adhere effectively to micro-uneven mounting surfaces of heat-generating elements due to insufficient adhesion, leading to high contact thermal resistance and a pump-out phenomenon of heat-radiating grease caused by thermal expansion and contraction.
Innovation Solution
A heat-radiating sheet with a specific area ratio of the heat-radiating grease after a heat cycle test, where the sheet is designed with grooves to retain the grease, ensuring the area ratio falls within a predetermined range, thereby suppressing the pump-out phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If heat-radiating sheet is used to fill air gap at contact interface, then heat conduction efficiency is improved, but contact thermal resistance increases due to insufficient adhesion to micro unevennesses
Solution Approach 1:
Heat-radiating grease is introduced as an intermediary substance between the heat-radiating sheet and the heat-generating element. The grease fills the micro unevennesses on the mounting surface, creating a compliant intermediary layer that ensures intimate contact between the sheet and the element, thereby reducing contact thermal resistance while maintaining good heat conduction efficiency.
2Reliability
If heat-radiating grease is allowed to intervene between heat-generating element and heat-radiating sheet, then contact thermal resistance is reduced, but pump-out phenomenon occurs due to thermal expansion and contraction
Solution Approach 1:
The invention optimizes the viscosity parameter of the heat-radiating grease within a specific range (10 to 500 Pa·s at 25°C). By controlling the viscosity parameter, the grease maintains sufficient thickness to prevent pump-out during thermal cycling while remaining thin enough to ensure good thermal contact and low thermal resistance.
3Loss of substance
If viscosity of heat-radiating grease is increased to suppress pump-out, then grease retention is improved, but heat conduction efficiency decreases
Solution Approach 1:
The invention establishes an optimal viscosity range (10 to 500 Pa·s) that balances two competing requirements: sufficient viscosity to prevent pump-out during thermal expansion/contraction, and low enough viscosity to maintain good thermal contact and heat conduction efficiency. This parameter optimization resolves the contradiction between grease retention and heat conduction.
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 reduces contact thermal resistance and prevents the pump-out of heat-radiating grease, enhancing heat transfer efficiency between the heat-generating element and the heat-radiating sheet.
Implementation Method 1
In order to thermally conduct the heat generated from the heat-generating element with efficiency into the heat-radiating component
Implementation Method 2
by allowing a heat-radiating grease to intervene between the heat-generating element and the heat-radiating sheet
Implementation Method 3
a remarkable pump-out phenomenon (phenomenon in which the heat-radiating grease flows out from a mounting section) occurs in the heat-radiating grease due to thermal expansion and thermal contraction of the heat-radiating sheet
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention relates to a heat-radiating sheet, in which when after sandwiching a heat-radiating grease between a heat-radiating sheet arranged on an aluminum plate and a glass plate, a heat cycle test is performed 100 cycles, an area ratio (S2/S1) of an area (S2) of the heat-radiating grease after performing the heat cycle test of 100 cycles to an area (S1) of the heat-radiating grease before performing the heat cycle test is 1.0 to 2.0. A heat-radiating sheet laminate (10) of the present invention includes a heat-radiating sheet (1) of the present invention and a heat-radiating grease layer (11) formed on the surface of the heat-radiating sheet (1) of the present invention. A structure (20) of the present invention includes the heat-radiating sheet (1) of the present invention, a heat-generating element (21), and the heat-radiating grease (11) intervening between the heat-radiating sheet (1) and the heat-generating element (21). A heat-radiating treatment method of a heat-generating element of the present invention includes a step of applying a heat-radiating grease on the heat-radiating sheet of the present invention and a step of arranging a heat-generating element on the heat-radiating sheet having the heat-radiating grease applied thereon. In accordance with the present invention, it is possible to provide a heat-radiating sheet which when allowing a heat-radiating grease to intervene between a heat-generating element and a heat-radiating sheet, is able to suppress a pump-out phenomenon of the heat-radiating grease, a heat-radiating sheet laminate including the heat-radiating sheet, a structure including the heat-radiating sheet, and a heat-radiating treatment method of a heat-generating element using the heat-radiating sheet.