Guojin Securities: High-density data centers raise product barriers to bring opportunities for material and structural upgrades to copper bars, the core component of busbars

The Zhitong Finance App learned that Guojin Securities released a research report saying that with the subsequent increase in GPU power consumption, the increase in the number of switching chips, and the advancement of supernode architectures, cabinet power supply capacity will become one of the important bottlenecks in AI infrastructure. Liquid-cooled busbars are expected to become an important product trend for high-power AI racks, and 800V high-voltage power supply will further improve bus performance requirements. The increase in liquid cooling penetration rate of rack busbars and the introduction of 800VHVDC HVDC architectures in new data centers will bring opportunities for material and structural upgrades to the copper bars, the core components of the bus.

Guojin Securities's main views are as follows:

AI servers are moving from stand-alone deployment to rack-level and super-node-level systems, and cabinet power consumption is rapidly improving

Entering the AI era, GPU/ASIC, NVSwitch, high-speed interconnect, optical module, etc. are integrated at a higher density in the same cabinet, and the entire cabinet has gradually become the smallest unit for collaborative design of computing power, power supply, cooling, and interconnection. Taking the Nvidia platform as an example, the GB200 NVL72 IT-side power is about 136 kW, the Vera Rubin NVL72 is expected to increase to about 209 kW, and the NVLink switching capacity and overall cabinet power density continue to rise. With subsequent increases in GPU power consumption, an increase in the number of switching chips, and the advancement of supernode architectures, the power supply capacity of the cabinet will become one of the important bottlenecks in AI infrastructure.

The rack bus is the core component of the AI cabinet's internal power distribution system. It mainly undertakes high current transmission, power distribution and tray connection functions, and is the “backbone of power supply” inside the cabinet

Under the centralized power supply architecture, after the power module outputs power, current needs to be distributed to load terminals such as calculation trays and exchange trays through a bus. Therefore, the bus's conductivity, temperature rise control, voltage drop level, connection reliability, and safety redundancy will directly affect the power supply efficiency and operation stability of the entire cabinet. Taking the Nvidia cabinet as an example, the GB200 NVL72 has a bus current of about 2,900 A under 50V centralized power supply, while the Vera Rubin NVL72 bus current is expected to increase to more than 5000 A, which has significantly exceeded the capacity boundaries of traditional cabinet power distribution components.

The difficulty brought about by the increase in power is not only “the current becomes larger”, but also that high current requires controlled transmission within a limited cabinet space

TEConnectivity's simulation data shows that under the 48V architecture, when the load power is raised from 200kW to 400kW, the maximum DC current is raised from 4166A to 8333A, the maximum temperature rise is raised from 7.79℃ to 33.59℃, and the maximum voltage drop is raised from 0.10V to 0.21V, and the temperature rise pressure increases significantly nonlinearly. At the same time, the internal space of the AI cabinet is occupied by chip cooling components, cables, and structural components, and it is difficult for the bus to simply rely on widening and thickening the copper discharge to solve the high current problem. In other words, after the power consumption of the AI cabinet increases, the bus is no longer an ordinary power distribution device, but a key basic component affecting the power density, thermal management efficiency, and system reliability of the entire cabinet.

Liquid-cooled busbars are expected to become an important product trend for high-power AI racks, and 800V high-voltage power supply will further improve bus performance requirements

Compared with traditional air cooling or natural heat dissipation busbars, liquid-cooled Busbars integrate conductivity, heat dissipation, fluid sealing, insulation protection, and reliability testing into the same component by introducing a cooling channel into the bus structure or collaborating with the liquid cooling system of the entire cabinet, so that the product barrier is upgraded from traditional copper row processing to an “electric-heat-liquid” integrated design and manufacturing capability. TE has introduced liquid-cooled vertical bus solutions for 200kW, 400kW, and 750kW; Molex presented a multi-channel liquid-cooled bus solution in 2026. The cooling efficiency can be increased by up to 20%, and the temperature rise is controlled at around 15℃ under 15,000 A current. The liquid-cooled Busbar has already entered the mass production application stage. In addition, the introduction of the 800V HVDC architecture will further improve the performance requirements of busbars in terms of insulation, safety protection, connection reliability, and structural integration, and promote the continuous upgrading of rack busbars from low voltage and high current components to high voltage and high reliability components.

Copper material is the core material for rack busbars

Copper has lower resistivity, higher conductivity, and higher thermal conductivity, which is more conducive to reducing line loss, controlling temperature rise, and compressing structural size in high current and high power density scenarios. Liquid-cooled Busbars and high-voltage busbars also place higher demands on copper. Product competition will further extend from basic copper row supply to high-purity copper/copper alloy materials, complex cross-section molding, cooling channel collaboration, welding and sealing, insulation coating, flatness control, and batch consistency management. Therefore, the rack bus upgrade will essentially bring about a comprehensive upgrade of materials, structures, processes and verification systems. Suppliers with high-performance copper, precision processing, customer collaborative development and batch quality control capabilities are expected to be the first to benefit in the AI cabinet power upgrade process.

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