Silicon carbide is affecting the entire electric vehicle industry and will be at the heart of electronics along with gallium nitride, another wide-bandgap material. During APEC, Exawatt CEO Simon Price analyzed SiC and its positive development in the battery electric vehicle (BEV) environment. “BEVs are fully electric vehicles, and we are very aware of the role SiC plays in that environment,” he said. “We combine our thinking about batteries and power electronics and see BEVs as an integrated system rather than individual components. We believe that non-hybrid BEVs will dominate vehicle sales in the next few years, by 2030 It will definitely be the same year.”
SiC forecasts must take into account several points such as SiC crystal growth and chip cost, SiC device and wafer demand, SiC adoption in EV-related converters, and global EV sales. It will take about five years to go from 0.1% of electric vehicles per household to about 1% globally. “It will take five years to get to 10%,
Price also highlighted a range of technologies, such as cell phones and personal computers, that have been adopted by American households in recent years. “By the late 1920s, the adoption rate of automobiles rose rapidly from 10 percent to about 60 percent,” he said. “The car growth curve flattened out until the 1940s, when it started growing rapidly again. What’s amazing about these numbers is that the newer the technology, the faster it’s going.”
Silicon carbide
Price believes that we should see mass adoption when BEVs become equivalent to internal combustion engines (ICE) and costs tend to come down and numbers are plentiful. “The combination of performance and cost will drive growth, and that’s where silicon carbide comes in,” he said.
To understand the impact SiC can have, let’s look at inverters, and how various BEVs use SiC MOSFETs instead of silicon IGBTs to provide greater vehicle range due to more efficient conduction and switching losses. All of this has led to the development of smaller, lighter power converters due to the combination of smaller passive components and reduced cooling systems. “Silicon carbide won’t drive EV adoption, but it can play a role in accelerating adoption by reducing overall system cost and increasing EV range,” Price said.
The biggest challenge is battery cost, which is falling but still poses a huge proportional challenge to the overall cost of BEVs. This is where SiC comes in handy again, as it helps reduce costs and improve the performance of these cells.
Let’s look at a 50 kWh battery (Figure 2), which is about what we consider an average capacity, and the cost of two batteries: $150/kWh, which is about the same as the average battery pack cost over the past year or two far, and $100/kWh, which is closer to the lowest-cost selling prices of Chinese manufacturers last year, and will soon be lower than what many battery manufacturers are selling. The first thing to note is that vehicle range has the biggest impact on cost: obviously, long-range BEVs are expensive, while short-range BEVs are cheaper. This is driven by the size and cost of the battery pack, which can be reduced by using more efficient power electronics.
“The rightmost bar in Figure 3 shows what happens when you use a BEV with a 50 kWh battery pack: you increase the efficiency of the powertrain, and you can increase the range by about 10% using a silicon carbide inverter, or , you can reduce the package size by about 10 percent and lower the cost of the car while keeping the range the same,” Price said. “It also makes the car lighter and saves space inside the car.”
So the main challenge is to reduce the cost of batteries per kilowatt hour, reducing the number of batteries we need, and that’s an opportunity for power electronics to take advantage of silicon carbide.
SiC in OEM
China leads in electric vehicle sales, followed by other countries, as shown in Figure 3. Tesla has a good share and is using SiC in its electric vehicles. “Other automakers have been slower to adopt SiC, mostly due to cost, and recently, Hyundai announced its new 800-V EV platform, the SiC E-GMP, and we expect more announcements this year,” Pry said. said.
The huge cost difference between SiC and silicon today is the substrate itself. Silicon carbide is an extremely difficult material to grow. It is the second hardest material in the world after diamond. It grows very slowly at high temperatures (above 2000°C), the process is very difficult to control, and manufacturing techniques are improving rapidly, leading to significant cost reductions.
“Why are silicon carbide crystals so expensive? Even after these cost reductions, you have to get the maximum performance out of them, which means increasing the current density,” Price said. “In other words, make smaller devices at a given current rating to get more out of each wafer. That means improving the quality of materials and devices to improve device performance. All of this will reduce The cost of SiC devices and inverters.”
Cost reductions in the future will be an important factor in the rate at which SiC is adopted in pure electric vehicles. The economic benefits of silicon carbide are greatest in long-range cars, which have the largest batteries.
As you move from a short-range car with a small battery and low-power motor to a long-range car with a larger battery and a larger motor, you benefit as the battery pack gets bigger, offsetting the increasing cost of the inverter, which will bigger.
“Of course, battery costs will continue to fall, so one might wonder whether the advantages of silicon carbide today will diminish over time,” Price said. “Our view is that silicon carbide costs will keep pace with battery costs over the next five years.”
Price presents a graph (Figure 5) showing the major OEMs using SiC. The red dots are the largest long-range vehicles (the blue dots use silicon IGBTs). The blue dot on the right is the point where SiC should be used to make it perform better.
Exawatt’s overall analysis shows that the market size for all SiC powertrain systems will be approximately $3 billion by 2030. “Actually, a large percentage of silicon carbide power converters will likely use these modules, which means the number may be higher,” Price.
An important factor in the growth of BEV sales is the length of time that vehicle models are produced. Once a new model is introduced, not much will change until the end of the model’s life cycle. So the real question is how long will it take to roll out the last ICE model. “For 10 years, we’ve seen all the electric models from mainstream manufacturers,” Price said. “Of course, we are still seeing a lot of hybrid-model strategies, where BEV and ICE models are options within the same model range, but manufacturers are increasingly abandoning these types of multi-mode strategies and moving to all-electric. The speed depends in part on how old the car is. It takes about five years for a new technology to enter a production car,
Price estimates that the tipping point could be 2026, with 2030 the last year to buy ICE. “A typical car model has a production life of about five to eight years,” he said. “We see BEVs reach some sort of tipping point in 2026, at which point the product is deemed good enough for the average buyer. It’s fun to drive, as affordable as an ICE, much cheaper to run, and Silicon carbide can play a role in reducing upfront and operating costs.”