PCB Thermal Via Layout for Sealed Electric Machine Electronics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to effectively dissipate heat generated by electronic components in compact, high-power rotary electric machines, particularly in sealed designs, where reduced component sizes and increased current densities hinder efficient heat transfer and electrical performance.
Innovation Solution
The solution involves a printed circuit board with a thermally and electrically conductive layer, where electronic components are soldered directly to the board, and a conductive mass is used in conjunction with vias to facilitate heat transfer to a heat sink, optimizing thermal and electrical connections while minimizing thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If electronic components are reduced in size to increase power density, then power output per unit volume is improved, but heat dissipation capability deteriorates
Solution Approach 1:
The patent utilizes the thickness dimension of the printed circuit board to create a three-dimensional thermal management solution. Thermal vias are drilled through the PCB thickness to conduct heat from the component side to the opposite side, where heat sinks can dissipate it. This vertical heat path adds a new dimension to heat dissipation, enabling effective thermal management in compact high-power electronic components without increasing their planar footprint.
Solution Approach 2:
The patent introduces thermal vias as intermediary structures that facilitate heat transfer from electronic components through the PCB to heat sinks. These vias act as thermal conduits, bridging the gap between heat-generating components and heat-dissipating structures. The vias are filled with thermally conductive materials to enhance heat transfer efficiency, serving as a mediating mechanism that resolves the contradiction between compact component size and heat dissipation capability.
2Volume of moving object
If component packaging is made more compact to reduce size, then device volume is reduced, but heat exchange surface area is reduced
Solution Approach 1:
The patent compensates for reduced planar heat exchange surface area by utilizing the vertical dimension. Thermal vias extend through the PCB thickness, creating additional heat exchange pathways in the vertical direction. Heat sinks are positioned on the opposite side of the PCB, maximizing their exposure to cooling airflow or liquid coolant. This three-dimensional thermal management approach maintains effective heat exchange capability while allowing compact planar packaging of electronic components.
Solution Approach 2:
The patent implements a nested thermal management structure where thermal vias are embedded within the PCB substrate, and heat sinks are positioned within the motor housing space. The thermal vias are nested within the PCB layers, conducting heat from internal components through the board thickness. This nested arrangement allows heat dissipation structures to be integrated within the existing device volume without requiring additional external space, thereby maintaining compact packaging while preserving heat exchange effectiveness.
3Quantity of substance
If tab dimensions are reduced to increase component density, then component packing is improved, but heat transfer ability deteriorates
Solution Approach 1:
The patent transitions from two-dimensional heat transfer through reduced tabs to three-dimensional heat transfer through thermal vias. Instead of relying on enlarged tab surfaces for heat conduction, the invention creates vertical heat pathways through the PCB thickness using drilled and filled vias. This allows heat to be conducted from compact surface-mount components through the PCB substrate to heat sinks on the opposite side, maintaining effective heat transfer despite reduced tab dimensions and enabling higher component density.
Solution Approach 2:
The patent employs composite thermal management structures combining multiple materials with complementary properties. Thermal vias are filled with thermally conductive materials such as copper, aluminum, or specialized thermal compounds that have superior thermal conductivity compared to the PCB substrate. This composite approach - combining the structural PCB material with high-conductivity fill materials - enhances heat transfer ability from compact components through the board thickness, compensating for reduced tab dimensions while maintaining component density.
4Power
If current density is increased to improve power output, then power density is improved, but thermal resistance increases
Solution Approach 1:
The patent addresses increased thermal resistance from high current density by creating three-dimensional heat dissipation pathways. Thermal vias distributed across the PCB provide multiple vertical heat escape routes, reducing thermal bottlenecks. The via array creates a distributed thermal conduction network that efficiently carries heat away from high-current trace regions and components, preventing localized overheating and reducing overall thermal resistance despite increased power density.
Solution Approach 2:
The patent introduces thermal vias and thermally conductive adhesive layers as intermediary heat transfer structures that mediate between high-current power traces and heat sinks. These intermediaries provide low thermal resistance pathways that bridge the thermal gap created by high current densities. The thermally conductive adhesive bonding components to the PCB and heat sinks creates continuous thermal pathways, reducing thermal resistance and enabling efficient heat removal from high-power density regions.
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 approach enhances heat dissipation and electrical performance by spreading heat over a larger area, reducing thermal and electrical resistance, and allowing for higher current densities without overheating, thus addressing the limitations of previous technologies.
Implementation Method 1
a conductive mass which is connected to the printed circuit board and to the electronic component through the first layer of the printed circuit board... the electronic component and the conductive mass are in heat exchange relationship... at least through the first PCB layer on which both are preferably soldered
Implementation Method 2
The direct soldering of the base 8a of the electronic component 8 to the conductive mass 15 and/or the conductive layer 12a of the PCB jointly or separately define a thermal and electrical connection between the electronic component 8 and the conductive mass 15
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
An electric machine comprises a casing (2), a cap (3) covering the casing to define an enclosure, a heat sink (7), an electronic module (6) mounted inside the enclosure and comprising a printed circuit board (9) having a first conductive layer (12a) defining, at least partly, a first face (10), or top face, of the printed circuit board, a second conductive layer (12b) defining, at least partly, a second face (11), or bottom face, of the printed circuit board, a plurality of vias (13) which pass through the printed circuit board between the top face, at the first conductive layer, and the bottom face; the electronic module comprises at least one electronic component (8) soldered to the printed circuit board (9) on the first conductive layer by its own base and disposed, at least partly, on top of a first part (14) of the vias, a conductive mass (15), soldered to the printed circuit board (9) in proximity to the electronic component and disposed, at least partly, on top of a second part (16) of the vias; the conductive mass forms part of the circuit of electrical connections through which the electric power supply of the electric machine flows and is in electric and heat exchange relationship with the electronic component, while the second face (11) is in heat exchange relationship with the heat sink (7).