Thermal Challenges of 5G Stations

  By 2025, the Telecommunication industry will consume 20% of the world's electricity, and in the mobile communication network, base stations are the major power consumers, and about 80% of the energy consumption comes from widely distributed base stations. More dense base stations means higher energy consumption, which is a major cost challenge for 5G networks.

  In terms of energy structure, power consumption means higher costs and greater indirect pressure on environmental pollution. From the perspective of thermal design, the heat generation of the base station increases, and the difficulty of temperature control increases suddenly.

Engineers who have worked in the communication industry know that communication base stations are usually installed on iron frames on the roofs of buildings and high places in the wild. Volume and weight are critical to the ease of installation of equipment. Coincidentally, power consumption, volume, and weight are all core design boundary conditions in thermal design.

From the past design habits, the base station is a typical closed natural heat dissipation device (outdoor application requires strict waterproof and dustproof). After the heat is emitted from the components, there are only two places:

1. Absorbed by internal devices - heat is converted into internal energy, causing the temperature of the device to rise;

2. Due to the temperature difference, the heat is transferred from the high temperature object to the low temperature object - when the temperature is stable, the heat transfer rate = the heat generation rate.

To reduce the volume and weight of products, the demand for thermal design of such products has evolved to maximize heat transfer efficiency and reduce heat transfer thermal resistance in the same space. The heat transfer thermal resistance here is divided into internal thermal resistance and external thermal resistance.

The reduction of internal thermal resistance requires a reasonable chip layout, so that the heat source itself is closer to the heat dissipation shell. This is a collaborative effort between hardware engineers and thermal design engineers.

From a material point of view, a thermal interface material needs to be applied between the chip and the housing. 5G base stations may promote a great improvement in thermal interface materials, which are reflected in the following aspects:

1. The lowest possible thermal resistance - higher thermal conductivity and better interface wetting are required;

2. Reliability - base stations are used in complex outdoor environments, all over the world, with a temperature range of -40C~55C, and maintenance is difficult after failures - excellent thermal stability, anti-sag, anti-cracking

3. Usability - 5G base stations are used in a large amount, and multiple chips share the heat dissipation of the chassis, which requires automation of material assembly and stress generated during the assembly process.

From the perspective of the casing, the power consumption is increased, and a more reasonable fin form needs to be designed to match the high power consumption material level of the base station, and materials with lower density, better thermal conductivity and strong corrosion resistance are required. The application of the inflation plate in the base station is based on its high thermal conductivity and low density. Due to the low density and high thermal conductivity properties, the application of two-phase flow products in base stations will become more and more extensive. The rise of semi-solid die casting and other processes has also promoted the improvement of thermal conductivity of die casting casing materials.

The efficiency of natural heat dissipation is limited. With the increase of power, air cooling and liquid cooling of base stations are also being studied. When the temperature is well controlled, it not only improves the reliability of the product, but also reduces the power consumption of the device.