At the Winter Olympics, Toyota used the MIRAI 2 as a transportation service vehicle to undertake the transportation of spectators and staff in the mountain area.
This car is based on the GA-L rear-drive platform, the vehicle quality of 1900kg, body size length and width 4975/1890/1470mm, wheelbase of 2920mm. The configured drive motor has a maximum power of 134 kW. At present, the Hyundai Nexo, as the two main sales models, basically occupy more than 90% of the global fuel cell vehicles.
In 2021, Nexo will sell 9K units worldwide, mainly in South Korea and 430 units in the United States; and the MiRAI 2 model will sell about 6K, mainly in Japan and the United States, of which 2,629 units will be sold in the United States.
From the overall characteristics, the advantages and disadvantages of MIRAI 2 are as follows:
● The benefits can be easily achieved at 650 kilometers, hydrogenation only takes 5 minutes, driving characteristics are better, and the price is relatively acceptable
● The disadvantage is that the entire acceleration characteristics, including the overall space and seat state, are not very comfortable due to the characteristics of the layout.
Figure 1. Evaluation comparison of toyota two-generation models and hyundai fuel cell vehicles
Part 1 System features of MIRAI2
The second generation of MIRAI models, GA-L platform to create mirai 2 can be equipped with three high-pressure hydrogen tanks, compared to the first generation of MIRAI models, the fuel capacity and range of the new car can be increased by 30%, the use of a new material battery technology, equipped with lithium-ion high-voltage battery, from the technical objectives, the current hydrogen fuel cell passenger car in the endurance level also has a little advantage, MIRAI XLE EPA range of 402 miles (about 647 kilometers).
Figure 2. Mirai's system layout
Since the maximum power of the stack is 128kW, after the 1.24kWh lithium battery is configured, the overall system output is also limited to 128kW, which means that the MIRAI2 fuel cell passenger car does not actually bring consumers a very cool acceleration experience.
Figure 3. System parameters for MIRAI2
From the perspective of the layout of the fuel cell system, the stack occupies the position of the front cabin, and after the three hydrogen storage tanks and the drive unit are arranged, the overall space of the vehicle is basically the same as that of the internal combustion engine vehicle. According to the scale of the figure below, if you want to deploy fuel cells on smaller models, you will either have a short endurance or further occupy other space.
Note: The position of this 1.24kWh lithium battery is basically similar to the position of the hybrid
Figure 4. The overall placement of mirai2
Part 2 Dynamic feature case
Under the acceleration characteristics, the 128 kW stack outputs 584A and 591A, the lithium battery provides 19 kW of power, and the integrated motor output 135 kW. In terms of the segmentation of acceleration,
Figure 5. MIRAI1&2 compares data measured under the Acceleration characteristics of the Nexo
From the current point of view, the further improvement of the acceleration characteristics of luxury pure electricity will continue to open this gap.
Figure 6. Mirai1&2 and Nexo compared to the whole vehicle and power
Compared with the WLC and the actual RDE data, the hydrogen consumption per 100 kilometers is about 0.63 boxes of 0.85kg, which is due to the Nexo (the SUV model itself consumes more energy).
Figure 7. Data on hydrogen consumption for 100 kilometers under different operating conditions
At high speeds, the stable output characteristics of the stack are still very good, and the overall power matching can be reflected by the fluctuation of the stack voltage.
Figure 8. At present, fuel cells are more adaptable to high-speed working conditions
In actual tests, the vehicle's stable output power is 124kW+/-6kW, and the test bench can be pulled up to 150kW.
Figure 9. The highest power of the stack is tested down the results
Figure 10. Fuel cell batteries
Summary: With Hyundai suspending the launch of next-generation fuel cells on high-end models, there are still relatively few car companies promoting fuel cell companies in the passenger car field worldwide, and the two companies that are promoting this technology in China are Great Wall and SAIC. If nothing else, if the competitiveness of vehicles is evaluated from the perspective of consumers alone, the existing fuel cell passenger car models are not particularly good.