Recently, power electronics are more popular, and I have sorted out some of the views of several materials here.
2022 is a very important year for the use of silicon carbide in China, mainly because the current 800V system has brought a lot of changes, and what are the differences from various levels, I want to discuss with you according to the carding material.
Let's first talk about IGBT, in fact, in the field of electric vehicles, we especially want to thank Infineon, before the European auto companies did not come in, Nissan, Honda and Toyota are around their own technology to develop inverters, and the cooling and iteration technology of IGBT as the core; Tesla before the introduction of SIC, but also the use of single tube IGBT to do high-power drive, after Infineon did the standard package 6in1 IGBT, greatly reduced the difficulty of inverter development.
Figure 1. Several uses of IGBT
In the design of the inverter for high power, Tesla's engineers used discrete single-tube parallel connection, built-in single-tube heat dissipation and cooling technology and power stack busbar technology, which made this thing power increased, but the assembly process was quite complicated.
Figure 2: Tesla single tube IGBT design
So in the iteration, Tesla is the first to directly iterate into a SiC in a 400V product. According to the data reference given by Cree, as shown in the following figure:
Power density and efficiency:
Figure 3. If you compare SiC and IGBT by power and current density
Of course, from the perspective of the efficiency of the inverter itself, it is mainly based on the parameter specifications to benchmark:
▲Table 1. Comparison of motor, inverter and vehicle parameters
That is to say, the efficiency brought by 400VSiC has only caught up with many subsequent vehicles, and cars like the Lucid Air can also achieve higher Mile/kWh.
Figure 4: The energy efficiency of the whole vehicle is summarized by time
The following figure is the dynamic characteristics, in the running UDDS and HWFET two different operating conditions, the comparison of inverter efficiency, from here there is still a dynamic difference, from 4% -7% difference.
Note: This data was done by FEV and used abstract data for comparison.
Figure 5. Efficiency differences between SiC and silicon-based IGBTs
That is to say, at the simulation level and the actual test is comparable, there is indeed a big difference in efficiency.
Figure 6. SiC Ford comparison
In this sense, 2% at the charging level, 6% at the operational level, the efficiency difference between the two systems is 8% - this is the same large battery, especially the 100-120kWh fast-charging battery, according to the efficiency of 8%, can be weighted to get 8-10kWh battery net benefit; if it is according to 0.8 yuan / Wh, the corresponding is about 6400-8000 yuan.
In the long run, not only the cost benefits, large-capacity batteries want to achieve high endurance and high efficiency, must first need the support of SiC.
Figure 7.Efficiency difference of silicon carbide
Summary: I think the efficiency difference of silicon carbide, although not large, but there is a significant improvement in large-capacity batteries, and then we have time to pay attention to the packaging of the SiC module.