The cooling challenges of 5G base stations
By 2025, the communications industry will consume 20% of the world's electricity, and in mobile communication networks, base stations are large consumers of electricity, and about 80% of energy consumption comes from widely distributed base stations. More encrypted base stations mean higher energy consumption, which is a major cost challenge facing 5G networks.
From the energy structure, power consumption means higher costs and greater indirect pressure on environmental pollution.
From the perspective of thermal design, the base station generates more heat, and the difficulty of temperature control rises sharply.
Engineers who have worked in the communication industry know that communication base stations are usually installed on iron frames on the roof of buildings and high places in the field. The size and weight are very important to the installation convenience of the equipment. "Coincidentally" is that power consumption, volume, and weight are the core design boundary conditions in thermal design.
From the past design habits, the base station is a typical enclosed natural heat dissipation device (outdoor applications require 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, heat is transferred from the high-temperature object to the low-temperature object-when the temperature stabilizes, 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 resistance in the same space. The heat transfer 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 the collaborative work of 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 the thermal interface material, which is manifested in the following aspects:
1. The lowest possible thermal resistance-higher thermal conductivity and better interface wettability are required;
2. Reliability-base stations are used in complex outdoor environments, all over the world, with a temperature range of -40C~55C, difficult to maintain after failure-excellent thermal stability, anti-sagging, and anti-cracking
3. Usability-5G base stations use a large amount of heat dissipation, and there are requirements for material assembly automation and stress generated in the assembly process.
The efficiency of natural heat dissipation is limited. With the approach of the power wall, air cooling and liquid cooling of base stations are also being studied. When the temperature is well controlled, it will not only affect the reliability of the product, but also reduce the power consumption of the device.
The static power consumption caused by the leakage current will rise rapidly with the rise of temperature, and with the evolution of the chip manufacturing process, the size of the transistor becomes smaller and smaller, and the leakage current will become larger and larger.
This means that the impact of temperature on chip power consumption will become more and more significant. If the temperature is not properly controlled, the power consumption of the product will increase, which will further heat up and cause the product's thermal cycle to deteriorate.
In recent years, electricity expenses have accounted for about 20% of operators' network maintenance costs. There is no doubt that power problems will become a huge pressure for operators to invest in 5G networks.
The government, operators, equipment vendors, and power grid companies need to work together to reduce the power consumption and electricity costs of 5G base stations.
