In 2020, we have seen several industries and material suppliers continue this trend to emphasize thermal considerations in product design and material selection.

Electric Vehicles
(EVs) are the future of the automotive industry; unfortunately, 2020 appears to have been the year of EV recalls due to battery fires. In China, 10,579 battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) were recalled due to fire risks at seven original equipment manufacturers (OEMs) (from January to October). General Motors recalled 68,667 Chevrolet Bolts, advising owners not to park their cars near their homes or in their garages due to the fire risk. This has not been limited to just a few OEMs. Industry contacts have revealed to IDTechEx that EVs will be safer than conventional vehicles, but currently, almost every OEM with EVs has had at least one serious fire-related incident. The causes of these fires have varied, with contaminants in the cells being the cause in some cases and poor thermal design allowing the batteries to overheat in others. Regardless of the primary cause, the importance of preventing cell overheating and detecting and containing thermal runaway is a topic of increasing importance.

Electric vehicles have several areas that require effective thermal management; their high-voltage batteries, traction motors, and power electronics all require a specific temperature range for optimal operation. How this is incorporated into the vehicle's cabin climate control is also a crucial area. In recent years, we've seen EV manufacturers move from passively or forced-air cooling of their batteries to water-glycol systems. In 2019, liquid-cooled batteries became the most popular form of battery cooling in EVs, a trend we see continuing in 2020. Nissan has historically been a leading proponent of air cooling in its EVs with the Leaf; however, the newly announced Ariya will use liquid cooling. Honda's first EV, the Honda, delivered its first orders in 2020 with a liquid-cooled battery pack. 2020 was also Porsche's first year of full deliveries for the Taycan, using an 800V battery pack with a sophisticated liquid cooling system.

Heating the passenger compartment is an area where combustion engine vehicles have an advantage over EVs. Excess heat from a combustion engine can be used to heat the cabin, whereas in an EV, many use a simple resistive heater, which drains the battery. Heat pumps, which can efficiently cool or heat a battery, are gaining increasing recognition. By cooling the battery, excess heat is sent to the passenger compartment heater; heat from the ambient air can also be redirected to the passenger compartment heater. Nissan was the first to use a heat pump in 2013, and by 2020, the vast majority of EV models launched had heat pumps installed, including models from VW, Hyundai, Mini, Vauxhall, and more. 2020 marked the first deliveries of the Tesla Model Y, the first Tesla model to use a heat pump. Since then, Tesla has announced that the updated 2021 Model 3 will also receive the heat pump.

With the rapid growth of the EV market, fire incidents may become more common, meaning a much greater focus on fire safety will be required from both a regulatory and material solutions perspective. The increasing use of liquid cooling systems and heat pump technologies demonstrates how manufacturers are recognizing the importance of thermal management and implementing solutions.

5G
promises incredible download speeds and extremely low latency communication. The first 5G smartphones arrived on the market in 2019, but the market expanded rapidly in 2020. Early 5G phones overheated quickly, especially in warm climates when using mmWave, often switching to 4G to keep temperatures down. The use of materials around the mmWave antenna also presents challenges with signal propagation. This presents an opportunity for material suppliers to address these challenges. Key markets will be for thermal interface materials (TIMs), heat spreaders, and thermal insulation materials. In recent years, there has been an increase in the application of vapor chambers in smartphones
to improve heat dissipation. However, their future is far from assured, as several high-end models still use graphite heat sinks due to their reduced complexity, cost, and weight. For example, in 2020, Samsung, which had previously touted vapor chambers, used either a graphite heatsink or a copper vapor chamber in the Note 20. Also in 2020, Apple's first 5G phones, the iPhone 12 line, all used graphite heatsinks and did not adopt vapor chambers.

In 2020, several new thermal materials for 5G applications were launched. For thermal interface materials (TIMs), Dow introduced the Dowsil TC-3065 Thermal Gel with a thermal conductivity of 6.5 W/mK and bond line thicknesses up to 150 microns, specifying applications in optical transceivers, solid-state drives, and other network devices. Henkel also announced its portfolio of TIMs for 5G infrastructure, including the gel-type Bergquist Liquid-Form TLF 6000HG with a thermal conductivity of 6.0 W/mK and its Bergquist Gap Pad TGP 10000ULM with a thermal conductivity of 10 W/mK, with plans for a 12 W/mK version. Another significant material launch in 2020 was the announcement of WL Gore's thermal insulation material for smartphones. This material has a lower thermal conductivity than air, helping to reduce hot spots on the device's surface, but it is also compatible with the new mmWave 5G antenna that can combat signal propagation.

As 5G expands, we are seeing increased utilization of mmWave frequency for higher download rates and lower latency.

The rapid growth of 5G deployment and especially the increased use of mmWave will present more challenges and opportunities for various materials and components within the thermal management market for both smartphones and telecommunications infrastructure.

Notable Acquisitions and Partnerships
In October 2020, Honeywell acquired Rocky Research, a Nevada-based company and leader in thermal, energy, and power management solutions. This acquisition will allow Honeywell to significantly expand its portfolio of thermal materials in the aerospace market. Rocky Research has previously secured several major contracts supporting the U.S. Department of Defense and Homeland Security.

Rex Materials Group (RMG) was acquired by Unifrax in June 2020. Unifrax provides high-performance specialty materials for thermal management, emissions control, batteries, specialized filtration, and fire protection, and is backed by Clearlake Capital Group, LP. The addition of RMG to the group expands Unifrax's portfolio of high-temperature engineered thermal components.

Another acquisition in October 2020 was that of Latent Heat Solutions, LLC (LHS), which was acquired by the CAVU Group. CAVU is a leader in thermal management and temperature control solutions. LHS provides thermal management systems for commercial battery energy storage and temperature stabilization of thermally sensitive components. LHS technology includes the use of phase-change materials (PCMs) and helps prevent thermal runaway in battery cells. The merger is said to enhance CAVU's innovative materials, engineering, and production capabilities.

KULR Technology Group, Inc. has announced a partnership with Airbus to provide its passive propagation-resistant battery design solutions for Li-ion batteries in aerospace applications. KULR's technologies include prevention of thermal runaway and internal short circuits. KULR's design incorporates a sleeve-like shield that separates the individual cells, carbon fiber cores, and liquid coolant.

Summary

2020 not only demonstrated the continued trend among manufacturers toward more effective thermal management, but also brought several issues to the forefront of public attention, including electric vehicle fires and recalls, as well as smartphone overheating. The ever-expanding market for thermal materials presents a variety of opportunities across diverse applications and will continue to grow rapidly in the coming years. From 2021 onward, the pressure on thermal management will continue to increase, a challenge that will be addressed through engineering and materials solutions in an ever-expanding range of applications.