Direct Pin-Fin PCB Cooling Without TIM or Coldplates
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Solution Overview
Problem
Conventional PCB materials like FR4 have low thermal conductivity, and existing solutions such as Metal Core Printed Circuit Boards (MCPCBs) face inefficiencies due to thermal interface materials (TIM) and coldplate top plates, which impede cooling performance in high-power density applications.
Innovation Solution
A direct pin-fin cooling system is implemented on PCBs, eliminating the need for TIM and coldplate top plates by using pin-fins extending from a metal core or FR4 material, with a polymer lid sealing the coolant channel and arc-welded joints for improved thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PCB materials (FR4) are used, then cost and ease of manufacture are improved, but thermal conductivity is insufficient for high-power applications
Solution Approach 1:
The patent employs a hybrid PCB structure combining FR4 substrate with integrated metal pin-fins and copper thermal vias. This composite approach allows the base material to remain inexpensive FR4 while the metal components provide high thermal conductivity pathways, resolving the contradiction between material cost and thermal performance.
2Reliability
If Metal Core PCB (MCPCB) is used to improve thermal conductivity, then cooling performance is improved, but thermal interface materials and coldplate top plates impede heat transfer
Solution Approach 1:
The patent extracts and eliminates the thermal interface material (TIM) and coldplate top plate from the heat transfer pathway. By integrating pin-fins directly into the PCB structure and allowing direct coolant contact, the design removes the thermal resistance layers that were present in conventional MCPCB solutions.
Solution Approach 2:
The patent merges the PCB substrate, heat dissipation structure, and coolant channel into a single integrated assembly. The pin-fins are directly attached to the PCB with solder joints, and the coolant flows directly against the pin-fins, combining multiple functions into one unified structure that eliminates intermediate thermal barriers.
3Reliability
If pin-fins extend through the PCB without direct coolant contact, then structural integrity is improved, but cooling performance is limited by intervening materials
Solution Approach 1:
The patent transitions from two-dimensional planar cooling to three-dimensional pin-fin protrusions that extend into the coolant flow path. This dimensional change creates direct fluid-structure contact surfaces, dramatically improving heat transfer efficiency while maintaining PCB structural integrity through proper pin-fin anchoring.
4Reliability
If direct pin-fin cooling is implemented, then thermal conductivity and cooling performance are improved, but package thickness and manufacturing complexity increase
Solution Approach 1:
The patent segments the heat dissipation function into discrete pin-fins that can be independently designed and manufactured. These pin-fins are created as separate features on the PCB using standard fabrication processes, allowing the complex thermal management function to be achieved through modular, manufacturable components.
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 thermal conductivity and cooling performance by directly transferring heat from components to coolant without intervening materials, reducing package thickness and cost while ensuring high reliability and insulation.
Implementation Method 1
a thermal path defined through the PCB directly from the heat generating component into the plurality of pin-fins without passing through an intervening cold plate wall or thermal interface material (TIM)
Implementation Method 2
A coolant medium such as a dielectric coolant fluid can be included in the cooling channel
Implementation Method 3
Each pin-fin can be joined to the metal core with an arc-welded weld joint
Data Source
Figure 1~2
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AI summary
Direct pin-fin cooling assemblies (100) are disclosed for a high-power printed circuit boards (PCBs) (102). The disclosure can solve the classical coldplate problem associated with liquid cooling of high-power PCBs (102), namely: (1) Inhomogeneous cooling due to the calorimetric heating up of the coolant (116), (2) thermal interface material (TIM) related quality issues such as dry-out effects, (3) high cost due to complicated metal coldplate structure, and (4) low thermal conductivity due to multi-layer structure. This includes incorporating pin-fin direct cooling into high-power PCB structures without additional coldplate structure or TIM. In this approach, a TIM and a top plate of coldplate can be removed. Thus, the cooling performance can be improved because the thermal conductivity between a liquid coolant (116) and a power device is increased.