As a core heat dissipation component in high-power-density applications, the optimization of heat dissipation via design for charging pile copper substrates requires consideration of the continuity of heat conduction paths, the matching of material thermal conductivity, and the rationality of structural layout. The core function of heat dissipation vias is to construct heat conduction channels perpendicular to the plane of the charging pile copper substrate, rapidly transferring heat from the heat source (such as power devices) to the underlying heat dissipation layer or structure. Design parameters must comprehensively consider factors such as via diameter, spacing, filler material, copper layer connections, and layout.
The choice of via diameter directly affects the thermal conductivity and fabrication feasibility of the heat dissipation vias. While smaller via diameters can increase via density per unit area, excessively small diameters increase fabrication difficulty, resulting in insufficient copper wall thickness and reduced thermal conductivity. Larger via diameters may affect the mechanical strength of the charging pile copper substrate and increase manufacturing costs. Therefore, a suitable via diameter must be selected based on the power density of the heat source and the thickness of the copper substrate to ensure a balance between heat transfer efficiency and structural stability. For example, for medium-power-density charging pile copper substrate applications, vias with a moderate diameter are recommended, ensuring both thermal conductivity and ease of industrial production. Optimizing via spacing is crucial for improving heat dissipation efficiency. Excessive spacing leads to discontinuous heat conduction paths and localized hotspots; insufficient spacing increases manufacturing costs and may negatively impact the mechanical properties of the charging pile copper substrate due to high via density. A reasonable spacing design requires thermal simulation analysis to ensure uniform heat transfer in the vertical direction while avoiding heat buildup in the horizontal direction. For example, using a densely packed via array under high-power devices effectively reduces thermal resistance, while spacing can be appropriately widened in low-power areas to balance cost and performance.
The choice of filler material has a decisive impact on the thermal conductivity of heat dissipation vias. Hollow vias, while inexpensive, are prone to solder absorption and air bubbles, leading to decreased heat conduction efficiency. Vias filled with conductive materials (such as copper fillers) significantly improve thermal conductivity but have higher manufacturing costs. Vias filled with non-conductive materials (such as thermally conductive adhesives) achieve a balance between cost and performance. For charging pile copper substrates, conductive filler materials are recommended, especially copper-filled vias. Their thermal conductivity is close to that of pure copper, significantly reducing thermal resistance and meeting the heat dissipation requirements of high power density scenarios.
The design of copper layer connections is fundamental to ensuring the effective operation of heat dissipation vias. Vias must directly connect to large-area copper foils (such as thermal pads, GND/Power planes), avoiding connections through thin traces to reduce thermal resistance. Simultaneously, vias should penetrate all heat dissipation-related layers to ensure continuous heat transfer in the vertical direction. For example, in multi-layer charging pile copper substrates, vias need to connect the top heat source, the middle heat dissipation layer, and the bottom heat dissipation copper foil, forming a complete heat conduction path.
Optimizing the layout can further improve heat dissipation efficiency. Matrix layouts are suitable for large heat dissipation areas, such as power modules; ring layouts are suitable for bottom heat dissipation of ICs, such as BGA structures; and fan-shaped layouts are suitable for localized high-heat areas, such as power MOSFETs. By combining thermal simulation analysis, the optimal layout can be selected based on the heat source distribution and power density to achieve uniform heat diffusion and efficient heat transfer.
The design of heat dissipation vias needs to be optimized in conjunction with the overall heat dissipation strategy of the charging pile copper substrate. For example, combining them with auxiliary heat dissipation structures such as heat sinks, heat pipes, or liquid cooling systems can further improve overall heat dissipation performance. At the same time, by optimizing the copper layer thickness, surface treatment process, and wiring design of the copper substrate, thermal resistance can be further reduced and heat dissipation efficiency improved.
