STMicroelectronics has been ramping up its silicon carbide (SiC) capabilities and capacities recently, in anticipation of growing demand from the sector...
The global electric vehicle (EV) market is expected to witness a strong growth amid the need for addressing future energy requirements, according to Mordor Intelligence. The market analyst forecasts the EV market to register a compound annual growth rate (CAGR) of more than 20% over the 2019 to 2025 forecast period.
In line with this, STMicroelectronics (ST) has been ramping up its silicon carbide (SiC) capabilities and capacities recently, in anticipation of growing demand from the sector.
In 2019, the company acquired Swedish SiC wafer manufacturer Norstel AB. This acquisition will enable ST to control the entire supply chain for a portion of its SiC devices at a time of constrained global capacity and position itself for a significant growth opportunity. In the same year, an agreement worth half billion dollars was signed with Cree to produce and supply its Wolfspeed SiC wafers to ST.
And in January this year, the company signed a multi-year SiC wafers supply agreement with SiCrystal, a ROHM group company having a top share of SiC wafers in Europe. The agreement governs the supply of over $120 million of advanced 150mm silicon carbide wafers by SiCrystal to ST during this period of demand ramp-up for SiC power devices. This will enable ST to increase the volume and balance of the wafers it will need to meet the strong demand ramp-up from customers for automotive and industrial programs over the next years.
Meanwhile, ST is also starting to build up its gallium nitride (GaN) capability. In February, the company announced a collaboration with Taiwan Semiconductor Manufacturing Co. (TSMC) to accelerate the development of GaN process technology and the supply of both discrete and integrated GaN devices to market. Through this collaboration, ST’s GaN products will be manufactured using TSMC’s GaN process technology.
Specifically, power GaN and GaN IC technology-based products will enable ST to provide solutions for medium and high-power applications with better efficiency compared to silicon technologies on the same topologies, including automotive converters and chargers for hybrid and electric vehicles. Power GaN and GaN IC technologies will help accelerate the megatrend of the electrification of consumer and commercial vehicles.
Focus on SiC
At a recent online media conference, ST highlighted its focus on SiC technology, for which the company has over 20 years of R&D experience, more than 70 patents, and significant know-how in high-volume production. According to Giovanni Luca Sarica, Head of Mass Market Business Development, Group Strategic Office Member, Automotive & Discrete Group, at ST, there is an acceleration in SiC adoption in the new energy vehicle (NEV) market. “It has been widely used in premium vehicles, thanks to its cost and performance advantage. But today, SiC is a real winning solution for medium-end and high-volume BEV [battery electric vehicles] that are taking the real cost advantage that SiC is offering.”
SiC technology allows BEVs to go beyond the limits of silicon, according to ST. Compared to silicon-based IGBTs and diodes in traction inverters and on-board chargers (OBCs), SiC MOSFETs offer higher efficiency, smaller form factor, less cooling effort because of their high thermal capabilities; faster recharging; and extended vehicle range.
Today, more than 40 percent of BEVs adopt SiC because of the cost benefit. Based on analyst forecasts, SiC will become even more popular in 2025—with more than 70 percent of electric vehicles expected to adopt the technology.
One issue, however, is the cost of SiC-based devices compared with silicon-based components.
“Yes, there is an extra cost compared with the IGBT. Thanks to a larger manufacturing scale and SiC manufacturing improvement, today, the cost gap between the SiC solution and standard IGBT silicon solution is narrowing compared to what was estimated one year ago by independent analysts,” says Sarica. “The cost advantage of SiC devices over silicon devices is not related to the devices themselves, but how car makers are saving a lot of money in terms of the total cost of ownership at vehicle level.”
Figure 1: Benefits of SiC in EV.
He further explains, “When you are adopting SiC, you can work at a higher frequency, which will lead to higher efficiency, and dimension and cost reduction of passive components. Passive components are a strong contributor at the overall cost of the application. So, when you adopt smaller passive components, you can also reduce the overall dimension of your modules—thereby, further reducing the overall cost of your application. But, there are other important benefits in terms of cost savings that car makers can achieve. For instance, you can achieve higher efficiency with SiC devices because you can reduce the dimension of the cooling system and batteries—both of which are strong contributors to the overall cost. At the end of the day, according to the independent analysts, the SiC solutions in each vehicle can contribute to save US$2,000 versus the traditional silicon-based solution. Clearly, this is the real cost advantage of SiC for car makers.”
While expediting its efforts in SiC, ST also has a strong commitment to GaN technology. According to Francesco Muggeri, Regional VP of Marketing & Applications, Power Discrete and Analog Products, Asia Pacific, there are no automotive-grade GaN devices qualified in the market yet. Despite this, GaN has a promising outlook for EVs, especially for applications at 600V or below.
“We are working with the largest institutions and major universities exploring the physical and thermal properties of GaN. This is a fundamental step to define and understand [the technology], and prevent any possible issues,” explains Sarica. “At the same time, ST is member of the JEDEC Committee dedicated to this specific topic, aiming to assess and define best methodologies and norms for testing GaN, and securing a proper level of reliability, which is important especially for automotive applications.”
“We are confident that the GaN components we are developing will be going through the same success story and automotive reliability standard as per our SiC products,” says Muggeri.
Challenges Remain Toward EV Adoption
The trend towards electric vehicles has been going on for a while, especially in the advanced markets such as the United States, Europe, Japan, and China, to name a few. But in Southeast Asia, EVs seem to be ‘stuck in traffic’ on their road to adoption. Issues include the heavy traffic jams in major roads and the lack of infrastructure.
In Singapore, for instance, electric car population is just above 1,100 units, around 0.2% of the total cars on the road in the city state.
Figure 2: Line of charging stations at a carpark.
“I think this is about user experience. It is true that electric vehicle adoption by individuals generate many questions. And one of these is the habit created in the past by driving a gasoline car. Countries that are more open to innovations are ready to take these new technologies quicker. However, in Southeast Asia, there are still countries besides Singapore which are still thinking of traditional vehicles in their minds,” says Muggeri. “Thinking that you are driving a vehicle utilizing electric power, you run out of power, you don’t think your friends will come in and give you a litre of gasoline. This is a very simple statement, but it is about the user experience. A quick and fast developing ecosystem for electric vehicles needs to be established. Think about what the strategy Tesla adopted in Hong Kong at the very beginning. The NEV charging stations were not diffused at the very beginning. To facilitate users, they first had to build the charging infrastructures and even offer energy charging service for free. These are things that enable people to change their mindsets. User experience is for sure one of the elements.
“The battery needs to be charged and it has to be charged as fast as possible. Today, there are several solutions in the market and their charging time are not anywhere close to the charging time spent in gasoline stations, which is around 8–10min. When you drive electric vehicles for long distances, you have to wait for an hour even with the DC/DC charging and very high level of power coming from the charging station, which leads to safety concerns. For sure, no one is ready to go on the highway if they have to travel for 1,000km to reach the destination without spending one hour, or an hour and a half, at the charging station. This is today our limitation. EV charging is a key element for delivering different user experiences. When we talk about mobility in a city, for example, every time you park a car, you would like to park the car in places where you can charge—so you change your driving habits.”
Another important element, according to Muggeri, is people’s sensitivity to environmental protection. “In this case, eco-friendly vehicles come immediately to people’s sensitivity. Today, perhaps Malaysia and Thailand are still quite green countries on their own. In the future, electric vehicles will be a subject for discussion in these regions,” he says. “Western countries and highly polluted cities like Shanghai, Shenzhen, Taipei, and Hong Kong, are using commercial vehicles—very advanced gasoline cars, which have just to be converted to equivalent electric cars. In reality, in overpopulated countries in Southeast Asia such as Indonesia, you need to solve another issue, which is about electric mobility.”
Muggeri adds that the purchase cost of EVs today is still very expensive, even though its total cost of ownership is much lower than gasoline cars. “This is the element that has created entry barriers in many countries and regions,” he notes.
M.H. TEY, Regional Senior Director of Marketing & Applications, Automotive Products, Asia Pacific, agrees. “The key challenge is the infrastructure, especially recharging infrastructure. Local governments need to build up and have the proper recharging infrastructure that can recharge partially or totally the vehicle in couple of few minutes, not hours,” he says. “We strongly believe that with the local governments’ continuous support by offering incentives, enforcing the regulation to mitigate the average fleet of CO2 emission, as well as a genuine demand for ‘low carbon mobility’ that is growing in the community, we shall see the trend picking up very soon also in Southeast Asia, for sure.”
Regarding the recharging issue for EVs, ST is now developing solutions to support electronics boards capable to 40kW and charging stations that can accommodate many of those boards.
Figure 3: Sample of EV car lithium battery pack.
“To charge above 200kW, and 350kW, is the new direction. You need about one hour to reach a good level—this is our limitation. But this is something we have been investing in; and along with the development of SiC and the digitalization of the boards, we will experience development in several directions,” says Muggeri. “One is about wireless charging, through which vehicles will continue the charging while running on the highway. But we are talking about different usages of your car. When it comes to the usage of family cars in a city, the key point is to charge the car frequently. This is the solution the market is taking so far. We are working to create charging solutions that deliver energy quickly. We also have to understand the big risk because when you charge at the charging station, you need to transfer 200kW or even higher power to vehicles in a short time, which means you need to have big levels of energy transferred through cables in a very safe manner.”
One of the trends is about the DC fast charging, and ST targets to charge the vehicle, fully or partially, in just a few minutes, Sarica says. “Basically, this goal can be achieved with the 350kW DC fast charging system. This is a really big business opportunity for players like ST, which has key technologies such as SiC for this kind of applications. While this presents a couple of challenges, it provides a couple of good business opportunities: when you need a huge amount of power within a short period of time, it is not so easy for the network to deliver what is needed,” he says. “Because of that, in a charging system like the one we mentioned, we need to have a battery pack, which is similar to the one used in a vehicle, to store the energy needed for recharging the car in just a few minutes. We can also recharge the battery when the charging station is in idle mode. This can be achieved, thanks to a solar panel system—an additional element to the overall charging system, which requires a large number of electronics and technologies supported by ST.
“In most of the cases, such technologies are very similar to the ones that are used for EV and vehicle batteries. We strongly believe that these trends will boost the overall demand for semiconductor in the years to come.”