The composition and principle of fuel cell vehicle

Fuel cell vehicles retain the chassis, driving system, suspension system, steering system and other parts of traditional vehicles, and also include fuel cells, high-pressure hydrogen storage tanks, auxiliary power sources, DCIDC converters, drive motors, motor controllers and fuel cells. Controllers and other components, different types of fuel cell vehicles, there are certain differences in their composition and working principles, here we will not introduce the same components as traditional vehicles, and the unique structure of fuel cell vehicles is configured according to “multiple power sources” The composition and working principle of different classification methods are briefly introduced.

1 PFC fuel cell vehicle

(1) Composition of PFC fuel cell vehicle
PFC fuel cell vehicles have only one power source, fuel cells, and all the power required by the vehicle during driving is supplied by the fuel cells alone. In addition to retaining the chassis system and suspension system of traditional vehicles, this type of fuel cell vehicle also includes fuel cell systems, fuel cell controllers, drive motors, DC/AC motor controllers, DC/DC converters, and DC/DC controllers, etc. part. The main components of the PFC fuel cell vehicle are shown in Figure 1.

Composition of PFC fuel cell vehicle
Figure 1 Composition of PFC fuel cell vehicle

(2) Working principle of PFC fuel cell vehicle
During the working process of the PFC fuel cell vehicle, the electric energy generated by the reaction of hydrogen and oxygen in the fuel cell is converted and transmitted to the driving motor through DCIDC, and the driving motor converts the electric energy into mechanical energy and then transmits it to the deceleration mechanism, thereby driving the vehicle.
This system has a simple structure, easy system control and overall layout; fewer system components are beneficial to the lightweight of the entire vehicle; the overall energy transfer efficiency is high, thereby improving the fuel economy of the entire vehicle. However, the fuel cell has high power and high cost; it has high requirements on the dynamic performance and reliability of the fuel cell system: because the fuel cell cannot store energy, this type of vehicle does not have the function of braking energy recovery.

2 FC+B fuel cell vehicle

(1) Composition of FC+B fuel cell vehicle
The structure of FC+B type fuel cell vehicle is somewhat different from that of PFC type fuel cell vehicle. This type of vehicle is to add auxiliary power battery to the structure of PFC type fuel cell vehicle to jointly drive the fuel cell vehicle power system. The main components of FC+B as shown in figure 2.

Composition of FC+B fuel cell vehicle
figure 2 Composition of FC+B fuel cell vehicle

(2) Working principle of FC+B fuel cell vehicle
In the process of accelerating the FC+B type fuel cell vehicle, the fuel cell and the power battery together provide energy for the motor, and the driving motor converts the electrical energy into mechanical energy and transmits it to the deceleration mechanism, thereby driving the vehicle; in the normal driving process, by The fuel cell provides energy for the whole vehicle: during the braking process, the drive motor becomes a generator, and the power battery will store the energy of the braking feedback. The charging and discharging response of the power battery is fast. When the energy demand changes greatly, the power battery quickly releases or absorbs energy to compensate and adjust the energy of the power system, thereby ensuring the power performance of the vehicle.
At present, this type of structure is widely used, and in essence, this type is a hybrid structure. Compared with the PFC type, the power requirement of the system to the fuel cell is greatly reduced, and the fuel cell can work under relatively ideal conditions, so that the working efficiency of the fuel cell will be improved. However, the addition of a power battery makes the vehicle structure more complex, increasing the difficulty of system control and overall layout.

3 FC+C fuel cell vehicle

(1) Composition of FC+C fuel cell vehicle
The FC+C fuel cell vehicle is similar in structure to the FC+B fuel cell vehicle. This type of vehicle replaces the power battery with a super capacitor on the structure of the FC+B fuel cell vehicle. The main composition of FC+C is shown in the figure 3 shown.

Composition of FC+C fuel cell vehicle
figure 3 Composition of FC+C fuel cell vehicle

(2) Working principle of FC+C fuel cell vehicle
In the process of accelerating the FC+C fuel cell vehicle, the fuel cell and the super capacitor combine to supply energy for the motor, and the driving motor converts the electrical energy into mechanical energy and then transmits it to the deceleration mechanism, thereby driving the vehicle to drive; in the normal driving process, the main Powered by the fuel cell: During braking, the drive motor becomes a generator, and the supercapacitor will store the energy of the braking feedback. The charging and discharging response of the supercapacitor is relatively fast, thus ensuring the dynamic performance of the car.
Compared with power batteries, supercapacitors have high charging efficiency, small energy loss, long cycle life, high energy recovery rate during braking, wide normal operating temperature range, and supercapacitors have higher instantaneous power, making the car easier to start. However, the low specific energy of supercapacitors, limited energy storage, short duration of peak power, and complex structure of the power system have become the key factors restricting the development of this type of fuel cell vehicle.

4 FC+B+C fuel cell vehicle

(1) Composition of FC+B+C fuel cell vehicle
FC+B+C fuel cell vehicle fuel cell, power battery and super capacitor are combined to drive the vehicle. The main components of the FC+B+C fuel cell vehicle are shown in Figure 4.

Composition of FC+B+C fuel cell vehicle
figure 4 Composition of FC+B+C fuel cell vehicle

(2) Working principle of FC+B+C fuel cell vehicle
During the driving process of the FC+B+C fuel cell vehicle, the fuel cell and the super capacitor together provide energy for the drive motor, and the drive motor converts the electrical energy into mechanical energy and transmits it to the deceleration mechanism, thereby driving the vehicle; when the vehicle brakes, the drive The motor becomes a generator, and the power battery and supercapacitor store the feedback energy. When the fuel cell, power battery and supercapacitor are combined to supply power, the energy output of the fuel cell is relatively smooth, and the fluctuation over time is small, while the low-frequency part of the energy demand change is shared by the power battery, and the high frequency of the energy demand change is borne by the supercapacitor. In this structure, the division of labor of each power source is more clear, so their advantages are better exerted.
The advantages of this structure are more obvious, especially in terms of component efficiency, dynamic characteristics, braking energy feedback and so on. lack
The point is also more obvious. The addition of supercapacitors and power batteries increases the mass and volume of the vehicle, makes the system more complex, and increases the difficulty of system control and overall layout.