The Role of Aluminum in Heat Management: Heat Transfer & Capacity

As the power density of new energy vehicles, 5G communications, artificial intelligence servers, and high-end industrial control equipment continues to rise, thermal management failure has become the core cause of electronic product downtime, thermal runaway of power batteries, and life decay of industrial equipment.

Among all kinds of metal thermal conductive materials, aluminum alloy has become the preferred substrate for thermal management systems due to its balanced heat transfer efficiency, excellent heat capacity, energy storage and buffering ability, lightweight characteristics and high cost-effectiveness.

This article provides a comprehensive answer to the question of why industrial thermal management systems are inseparable from aluminum alloys, and helps manufacturing enterprises to accurately select aluminum thermal management components and optimize the heat dissipation of the entire machine.

What is Heat Management?

Thermal management is a systematic project to control, channel, dissipate and regulate the heat inside the equipment and the whole set of industrial system, and the core objective is to keep the equipment in the rated optimal working temperature range.

The whole thermal management system relies on the three physical principles of heat conduction, heat convection and heat radiation to control the entire process of heat generation, flow and emission, and to ensure that electronic equipment, new energy equipment, industrial production lines, and power machinery can operate efficiently, stably and safely for a long period of time.

Main Sources of Heat

The vast majority of industrial equipment and electromechanical products will be spontaneous heat generation during operation, uncontrolled accumulation of waste heat will directly undermine the stability of the whole machine operation, the main sources of heat generation in the industrial scene is divided into four categories:

Fuel combustion heat: boilers, kilns, industrial heating equipment combustion of natural gas, coal, biomass fuels produce high-temperature process heat source, but also the industrial field of energy consumption and waste heat emissions of the largest plate;

Electrical and electronic heat: motor, transformer, power semiconductors, server chips, vehicle electronic control unit work power loss into heat, data centers, new energy vehicles and other high power density equipment, local heat accumulation problem is particularly prominent;

Mechanical friction heat: pumps, compressors, transmission structures and other moving parts friction heat, material drying, melting, curing and other chemical processing reactions will continue to release excess heat;

Process waste heat emissions: steam exhaust, high-temperature liquids, equipment, high-temperature shell to release a large amount of waste heat, this kind of waste heat needs to be recycled, but also need to be channeled in time to avoid equipment overheating.

The Value of Accurate Temperature Control

Many equipment failures, safety accidents and energy consumption problems, the root cause is the lack of thermal management, effective temperature control system has four core values:

Enhance operational efficiency: equipment overheating will trigger frequency reduction protection, output power decline, stable temperature control can ensure that the equipment is running at full capacity, reducing ineffective energy consumption;

Extend the service life of the equipment: sustained high temperatures will exacerbate material aging, hot and cold alternating deformation stress, perfect heat dissipation design can reduce the frequency of equipment downtime maintenance;

Avoid safety risks: to prevent equipment spontaneous combustion, explosion, power battery thermal runaway and other malicious accidents, in line with industrial production and automotive electronics industry safety standards;

Reduce costs and increase efficiency while taking into account low-carbon environmental protection: reduce maintenance and replacement costs, waste heat recovery system with aluminum heat dissipation structure, can reduce overall carbon emissions, in line with the requirements of low-carbon transformation of the manufacturing industry.

Why Aluminum is Ideal for Heat Management

Thermally conductive metals on the market include copper, carbon steel, stainless steel, aluminum alloy and other materials, comprehensive thermal conductivity, cost, weight, processing difficulty, corrosion resistance of the five dimensions, aluminum alloy is the only material suitable for large-scale industrialization of the thermal management of mass production needs, the core advantages are as follows:

Excellent Thermal Conductivity

Thermal conductivity is the core indicator of the material’s thermal conductivity, the unit is W/m-K, the higher the value, the faster the thermal conductivity and heat dissipation. Comparison of thermal conductivity parameters of mainstream thermal conductivity metals at room temperature:

Pure aluminum and general aluminum alloy: 205-237 W/m-K

Pure copper: 385-401 W/m-K

Carbon steel: 45-50 W/m-K

Stainless steel: 14-16 W/m-K

Comparison can be seen: aluminum thermal conductivity is 4-5 times that of carbon steel, stainless steel more than 15 times.

Although copper has better thermal conductivity than aluminum, aluminum can make up for the thermal conductivity gap by optimizing the structure of aluminum fins and increasing the surface area of heat dissipation, which can fully meet the needs of most industrial heat dissipation scenarios. Relying on its high thermal conductivity, aluminum can quickly conduct heat from the heat source to the heat dissipation surface, and then complete heat dissipation through air convection.

Lightweight and High Strength

Aluminum density is only 2.7g/cm³, only 1/3 of the density of steel (7.8g/cm³), the lightweight advantage in the car, airborne, portable equipment is irreplaceable.

At the same time, 6061, 6063 mainstream heat dissipation aluminum alloy has ultra-high specific strength, in the weight reduction at the same time can assume the role of structural support of the equipment, not only to reduce the vehicle, machine load, but also reduce the vibration brought about by the heat dissipation of the structural loss, and effectively enhance the new energy vehicles, drones, portable industrial control equipment range and operational stability.

Natural Corrosion Resistance

Aluminum will automatically generate a dense and self-repairing aluminum oxide passivation film after contacting the air, and can withstand humid air, salt spray, and mild chemical corrosion without the need for additional spraying of antirust paint.

Compared to steel, which requires galvanizing and painting to prevent rust, aluminum heat dissipation parts require almost no maintenance later, significantly reducing the cost of the entire life cycle of thermal management systems for outdoor equipment and marine equipment.

Unlimited Recycling

Aluminum mineral resources are abundant, the price of raw materials is much lower than copper, and the extrusion process of aluminum profile is mature, so it can be formed into a complex cooling fin structure at one time, and the processing cost is much lower.

In addition, aluminum supports 100% unlimited recycling, and the production of recycled aluminum requires only 5% of the energy consumption of virgin aluminum, which meets the requirements of the manufacturing industry’s circular economy and carbon-neutral development, and is the first choice for green thermal management materials.

Heat Transfer Properties of Aluminum

Three Basic Heat Transfer Principles

All thermal management systems rely on heat transfer by conduction, convection and radiation, and aluminum can be adapted to all three modes at the same time.

Three Modes of Heat transfer

Thermal conduction: the molecules inside the solid directly contact the heat transfer, but also the most core heat dissipation method of the radiator, aluminum high thermal conductivity to ensure that the heat from the chip, the battery and other heat sources to quickly conduct to the overall surface of the radiator;

Thermal convection: relying on air or coolant flow to take away the heat, aluminum extrusion can be extruded ultra-thin high-density fins to maximize the expansion of the heat dissipation area, to strengthen the natural convection and forced air-cooled heat dissipation effect;

Thermal radiation: no medium, through infrared radiation to emit heat, aluminum after anodic oxidation black treatment, the surface emissivity is greatly increased, passive heat dissipation ability is significantly enhanced.

The Effect of Alloy Composition on the Thermal Conductivity of Aluminum

Pure aluminum thermal conductivity is optimal, but the mechanical strength is insufficient; add magnesium, silicon, copper and other alloying elements, aluminum strength, extrusion molding ability to enhance, but the thermal conductivity will decline slightly. Three mainstream heat dissipation aluminum alloy performance comparison on the market is clear, can directly guide the engineering selection:

1050 Pure Aluminum

Thermal conductivity up to 220-230 W/m-K, is the best thermal conductivity performance of the three materials, the fastest heat conduction speed.

However, the texture of this aluminum material is soft, mechanical structure strength is poor, can not withstand vibration, extrusion and other external loads, only suitable for no structural load-bearing needs, the pursuit of the ultimate heat dissipation effect of the pure heat dissipation components.

6063-T5/T6 Aluminum Alloy

The thermal conductivity is maintained at 190-220 W/m-K, second only to 1050 pure aluminum in thermal conductivity, and has excellent extrusion molding performance, capable of processing high-density, ultra-thin, complex shapes of the heat dissipation fins, and is also the most cost-effective heat dissipation aluminum material.

This alloy is highly versatile and widely used in conventional extruded heat sinks, LED cooling profiles, general air-cooled cooling modules and other high-volume mass production heat dissipation products.

6061-T6 Aluminum Alloy

Thermal conductivity of 150-170 W/m-K, by the alloying elements affect the thermal conductivity has been reduced, but the structural strength, vibration and shock resistance performance has been greatly improved, mechanical properties are far better than the other two aluminum.

It is suitable for working conditions that require both heat dissipation and structural load-bearing, and is often used in vehicle heat dissipation panels, equipment heat dissipation shells, and integrated heat dissipation structural components with mounting stress requirements.

Heat Capacity of Aluminum

Specific heat capacity refers to the amount of heat absorbed per unit mass of material to increase 1°C, the formula is: Q = m × c × ΔT, where Q is the value of the change in heat, m is the mass of the material, c is the specific heat capacity, and ΔT is the value of the change in temperature.

The higher the specific heat capacity, the stronger the material’s ability to absorb heat, and the less likely the temperature will soar during a short heat surge, providing an excellent thermal cushioning effect.

Aluminum Specific Heat Capacity Side-by-Side Comparison

Aluminum alloy: about 900 J/kg-K

Pure copper: about 390 J/kg-K

Carbon steel: approx. 470 J/kg-K

Data visualization: under the same mass, the heat absorption capacity of aluminum is more than twice that of copper.

For chip instantaneous high heat, power battery fast charging instant heat, industrial control equipment intermittent heat and other heat fluctuation scenarios, aluminum can quickly absorb the sudden residual heat, inhibit the temperature surge;

After the heat source cools down, it can smoothly release the stored heat, avoiding the sudden drop of the equipment temperature, and significantly alleviating the material stress damage brought about by the alternation of heat and cold.

The Role of Aluminum Thermal Mass

Combined with the dual characteristics of low density and high specific heat capacity, aluminum thermal mass is suitable for lightweight temperature control needs:

On the one hand, the equipment can reach the standard working temperature quickly, and the response speed of start/stop is faster;

On the other hand, it can reduce the starting and stopping frequency of fans, liquid cooling pumps and other active cooling components, reduce the power consumption of the cooling system itself, and make the whole cooling system more silent and energy-saving, which is especially suitable for data center servers, new energy battery packs and other long-time continuous operation equipment.

Industrial Aluminum Profiles in Thermal Management

Relying on the mature and low-cost aluminum extrusion process, industrial aluminum profiles can be shaped into a complex one-piece heat dissipation structure, eliminating the need for multiple parts splicing, welding, assembly and other processes, which not only reduces the contact thermal resistance caused by assembly gaps, but also compresses the overall cost of production, and it is the most widely used and adaptable core substrate material in the current industrial thermal management system.

Combined with the current electronics, new energy, industrial control, lighting major industries, the actual cooling needs, industrial aluminum profiles derived from five categories of mature heat dissipation products, covering passive air-cooled, active liquid-cooled, structural heat dissipation integration of the whole scene:

Conventional extruded aluminum profile heat sink is the most popular heat dissipation component in the market, relying on the integrated molding of the dense fin structure to expand the heat dissipation contact area, adapting to the natural convection and forced air-cooling two heat dissipation modes, mainly used for passive heat dissipation of server motherboards, industrial inverters, power supply drives, industrial control motherboards and other conventional low and medium-power equipment, to meet the daily demand for stable heat conduction and cooling.

Aluminum water-cooled plate, also known as aluminum cold plate, the profile of the internal reserved closed fluid flow channels, can be passed into the coolant to achieve efficient liquid cooling heat dissipation, tailored for high heat flow density, closed without ventilation space equipment, widely used in new energy power battery modules, industrial high-power lasers, vehicle power semiconductor modules and other high-heat core components, heat dissipation uniformity is far superior to the ordinary air-cooled radiator.

LED integrated heat dissipation aluminum profile shell to achieve the structure of the protection and heat dissipation function of two in one, without the need for additional installation of an independent radiator, the profile shell itself can quickly channel the heat generated by the light source, while both dustproof, waterproof, UV protection capabilities, perfectly adapted to the outdoor street lamps, industrial lamps, outdoor lighting fixtures, such as long-term open-air work of the lighting equipment.

Aluminum profile shell for power battery is a structural heat dissipation integrated component, which not only can be used as the sealed protective shell of the battery pack to withstand the vibration and impact of the vehicle driving process, but also can evenly conduct the heat generated by the electric cell, balance the temperature difference inside the battery pack to avoid overheating of localities that may cause safety hazards, and take into account the triple demand for structural strength, lightweight, and temperature control in the whole area.

Aluminum profile frame of industrial control chassis integrates the heat conduction path inside the equipment support frame, using the thermal conductivity of the aluminum profile itself to take away the heat accumulated by the components inside the chassis without the need for additional external cooling accessories, streamlining the structure of the entire machine at the same time, realizing the full range of passive heat dissipation inside the chassis, and adapting to the compact industrial control equipment and embedded electrical equipment.

Points for Customized Design of Aluminum Heat Sink Structure

Standardized aluminum heat sinks are often unable to match the heat dissipation conditions of niche equipment and customized machines, so customized aluminum heat sink profiles have become the mainstream choice for high-end thermal management solutions.

In the design stage, it is necessary to distinguish between natural convection and forced convection two kinds of heat dissipation environments, accurately optimize the height of the heat dissipation fins, the thickness of the fins and the spacing of the fins, to maximize the surface area of the heat dissipation under the premise of ensuring smooth ventilation and not accumulating dust and blocking the wind; and at the same time, with the black anodic oxidation surface treatment, to greatly enhance the heat radiation coefficient of the aluminum surface, and to enhance the passive heat dissipation capability.

After the profile is extruded and molded, it can be processed through CNC precision machining to complete secondary processing such as opening, tapping, and corner cutting, so as to accurately fit the installation position of the equipment and the heat source on the surface, and eliminate the thermal resistance of the assembly gap. Measurement data show that after simulation optimization, structure customization of aluminum thermal profile, compared with the general standard heat sink, the overall cooling efficiency can be steadily increased by 15% -30%, the whole machine temperature control effect is more outstanding.

Aluminum vs Other Materials in Heat Management

Aluminum vs Copper

The thermal conductivity of pure copper can reach 385-401 W/m-K, the thermal conductivity is far more efficient than aluminum alloy, the short distance heat spread faster, and the face of ultra-high heat flow density heat source when the temperature control effect is more excellent.

But there are two fatal shortcomings of copper: one is a great weight, density of 8.9g/cm³, the weight of the same specifications for the triple aluminum, will significantly increase the car, portable equipment machine load;

Second, the high cost of raw materials and extrusion processing, mass production costs are 3-5 times that of aluminum, and copper plastic processing is more difficult to extrude ultra-thin dense fins.

Therefore, copper is only suitable for small space, instantaneous heat generation, weight and cost insensitive niche scenarios, such as high-end CPU core substrate, high-power chip base.

Aluminum alloy, with its balanced overall performance, is suitable for most general-purpose cooling scenarios. The most mature compromise in the industry is to use copper base with aluminum fins, using copper to quickly channel the concentrated heat from the core, and relying on the large-area fins of aluminum to complete the convection cooling, which takes into account the heat dissipation performance, lightweight, and production costs.

Aluminum vs Carbon Steel

Carbon steel and stainless steel are more often used as structural support materials, completely unsuitable for heat dissipation as the main material. Ordinary carbon steel thermal conductivity is only 45-50 W/m-K, stainless steel thermal conductivity is as low as 14-16 W/m-K, heat buildup is difficult to conduct outward, and it is very easy to overheat the local problem.

At the same time, carbon steel is very easy to oxidize and rust, must be extra galvanized, powder coating anticorrosion treatment, superimposed on the subsequent maintenance costs; stainless steel corrosion performance is excellent, but the thermal conductivity is almost negligible.

On the contrary, aluminum alloy comes with self-healing oxidation protection layer, no need for complex anticorrosion treatment, while the thermal conductivity is 4-5 times that of carbon steel, stainless steel, more than 15 times, not only can bear the basic structural support, but also efficiently complete the heat evacuation, both structural and heat dissipation needs of the integration of the components, steel is completely unable to replace the aluminum material.

Three Major Judgment Criteria for Material Selection

Throwing away the material parameters to talk about the selection of no practical significance, the actual project only needs to be combined with the three core dimensions can be judged:

First, look at the heat load, high heat flow density, small heat dissipation area, strict temperature control needs to choose copper, conventional heat generating equipment, the need for a large area of heat dissipation fins preferred aluminum alloy scenes;

Secondly, look at the operating conditions, outdoor open air, coastal salt spray, humid industrial environments preferred aluminum alloy, eliminating steel anti-corrosion process and maintenance costs;

Finally, the mass production demand and lightweight indicators, new energy vehicles, portable electronics, communication equipment and other weight-sensitive, as well as large-scale mass production projects, aluminum alloys have always been in the leading position in terms of cost-effectiveness and process adaptability.

Emerging Trends in Aluminum Thermal Solutions

New Energy Vehicle

After the popularization of fast charging in new energy vehicles, the battery temperature control requirements have become more and more stringent, and the integrated aluminum liquid cooling panels and battery pack aluminum integrated heat dissipation framework have become the mainstream of the industry. Vehicle enterprises gradually eliminate redundant structures, the heat dissipation structure and body bearing structure integration, relying on aluminum lightweight advantages to enhance the vehicle range, 2035 years ago, the automotive aluminum thermal management accessories market will continue to grow at a high rate.

High-Power Electronic Precision Heat Dissipation

5G base station, AI server power consumption continues to rise, micro-runner aluminum profiles, ultra-thin fins extrusion heat sink has become a necessity, with AI simulation optimization of fin structure, aluminum thermal solution can carry a higher heat load in a smaller volume, to meet the demand for high-density integration of precision electronics.

Recycled Aluminum Heat Sink Profile

Driven by the dual-carbon policy, thermal management manufacturers are gradually adopting a high proportion of recycled aluminum to produce heat sinks, which significantly reduces production carbon emissions without reducing thermal conductivity and mechanical properties, and closed-loop recycling of aluminum thermal accessories has become the industry standard.

Best Practices for Selecting Aluminum Thermal Components

Selection of Core Considerations

Thermal conductivity requirements: 1050 pure aluminum for extreme heat dissipation, 6063 for universal heat dissipation, and 6061 for structural load-bearing;

Working conditions: outdoor corrosive environment with anodized treatment as standard, high-temperature confined scenes to strengthen radiation heat dissipation;

Production volume: extruded aluminum profiles for mass production, CNC machined aluminum for small batch prototypes;

Structural load: vibration, shock conditions give priority to high-strength 6061 aluminum alloy.

Suggestions for Surface Treatment

Black anodizing: enhance the heat radiation ability, passive heat dissipation effect increased by more than 40%, the preferred process for heat sinks;

Powder coating: stronger protection, suitable for high appearance requirements, heat dissipation requirements of the general shell structure;

Thermally conductive interface gasket: heat source and aluminum contact surface with the addition of thermally conductive gaskets, eliminating the contact thermal resistance, and further enhance the overall heat dissipation efficiency.

Conclusion

Outstanding heat transfer performance ensures rapid heat evacuation, excellent heat capacity can smoothly buffer transient thermal shock, with mature industrial aluminum extrusion process, can be customized to fit the electronics, automotive, communications, new energy industry cooling solutions.

Although copper has stronger thermal conductivity, it cannot be popularized on a large scale due to its weight and cost; steel has obvious shortcomings in thermal conductivity, which makes it difficult to perform precision heat dissipation scenarios.

In the future, with the continuous development of high-power electronics and new energy industries, integrated, lightweight, green and recyclable aluminum thermal management solutions will continue to be the mainstream choice of the global thermal management industry.