Fuel cell system

Abstract

The invention relates to the technical field of fuel cells, and discloses a fuel cell system which comprises an electric pile, a main air inlet branch, an auxiliary air inlet branch and a control assembly, the main air inlet branch comprises a main air inlet pipe, a first air inlet and a first air outlet are formed in the two ends of the main air inlet pipe respectively, the first air outlet communicates with an air inlet of the electric pile, and an electric control valve, an air compressor and an intercooler are sequentially arranged in the air inlet direction of the main air inlet pipe; the auxiliary air inlet branch comprises an auxiliary air inlet pipe, a second air inlet and a second air outlet are formed in the two ends of the auxiliary air inlet pipe respectively, the second air outlet is communicated with the electric control valve, an oxygen increasing device is further arranged on the auxiliary air inlet pipe, and an oxygen separation module is arranged in the oxygen increasing device; the control assembly is electrically connected with the electric pile, the air compressor, the electric control valve and the oxygen separator. The single-air-compressor air inlet system is adopted, the air inlet oxygen content requirement of the electric pile can be met under different altitude working conditions, stable work of the electric pile is guaranteed, the service life of the air compressor is prolonged, and the reliability of the air compressor is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and more particularly to a fuel cell system. Background Art

[0002] Fuel cells are power generation devices that directly convert the chemical energy of hydrogen and oxygen into electrical energy. Due to their high efficiency and zero emission characteristics, fuel cell vehicles have shown great development prospects. With the application and promotion of fuel cells in the automotive field, the requirements for their environmental adaptability in different application scenarios are becoming higher and higher, and the demand for their stable operation at different altitudes is becoming more and more urgent.

[0003] The stack in the fuel cell system is very sensitive to the supply of oxygen. When the fuel cell engine is running at high altitude, the air pressure, oxygen content and oxygen partial pressure in the air gradually decrease with the increase of altitude, resulting in a gradual decrease in the amount of oxygen entering the stack to participate in the reaction. When the oxygen supply is too low, the output power and output efficiency of the stack will decrease. In severe cases, the stack will not work properly, affecting the power performance and safety performance of the vehicle. Therefore, in order to enable the fuel cell system to operate efficiently and stably in a high-altitude environment, oxygen intake compensation is required.

[0004] In the prior art, in order to achieve oxygen intake compensation for the fuel cell system in a high-altitude environment, most of the single air compressor intake systems are used. The single air compressor intake system adopts a control strategy to increase the speed of the air compressor through mechanical adjustment to increase the amount of air entering the stack. Although this method can increase the amount of oxygen entering the stack to a certain extent, once the altitude exceeds the tolerance range of the air compressor, it will cause the output power of the stack to decrease, affecting the power performance of the vehicle, and high-load operation is also extremely detrimental to the life and reliability of the air compressor. Summary of the invention

[0005] The purpose of the present application is to provide a fuel cell system that uses a single air compressor system to meet the intake oxygen content requirements of the fuel cell system stack under different altitude conditions and ensure stable operation of the stack.

[0006] To achieve the above-mentioned purpose, a fuel cell system adopted in the present application includes: a fuel cell stack, a main air intake branch, an auxiliary air intake branch and a control component;

[0007] The main air intake branch comprises a main air intake pipe, the two ends of the main air intake pipe are respectively a first air intake port and a first air outlet, the first air outlet is connected to the air intake port of the fuel cell stack, and an electric control valve, an air compressor, and an intercooler are sequentially arranged along the air intake direction of the main air intake pipe;

[0008] The auxiliary air intake branch comprises an auxiliary air intake pipe, the two ends of the auxiliary air intake pipe are respectively a second air intake port and a second air outlet, the second air outlet is communicated with the electric control valve, an oxygenator is also arranged on the auxiliary air intake pipe, and an oxygen separation module is arranged in the oxygenator;

[0009] The control component is electrically connected to the fuel cell stack, the air compressor, the electric control valve, and the oxygen separation module, respectively, and the control component is configured to:

[0010] Determine the oxygen demand flow rate of the fuel cell according to the required power of the fuel cell;

[0011] Obtaining an actual oxygen flow rate at an air inlet of the air compressor;

[0012] According to the difference between the actual oxygen flow rate and the required oxygen flow rate, the rotation speed of the air compressor, the opening of the electric control valve and the opening and closing of the oxygen separation module are adjusted.

[0013] As a preferred technical solution, according to the actual oxygen demand flow rate and the difference between the oxygen demand flow rate, the speed of the air compressor, the opening of the electric control valve and the opening and closing of the oxygen separation module are adjusted, specifically including:

[0014] When the actual oxygen flow rate is equal to the required oxygen flow rate, switching the electronically controlled valve so that the air inlet of the air compressor is connected only to the first air inlet;

[0015] When the actual oxygen flow rate is less than the required oxygen flow rate, the method includes:

[0016] S1, increasing the rotation speed of the air compressor;

[0017] S2. When the speed of the air compressor reaches the maximum value and the actual oxygen flow rate is still less than the required oxygen flow rate, the electric control valve is switched so that the air inlet of the air compressor is connected to the first air inlet and the second air inlet respectively;

[0018] S3. If the actual oxygen flow rate is still less than the required oxygen flow rate, start the oxygen separation module.

[0019] As a preferred technical solution, the oxygen separation module includes a PTC and an oxygen permeable membrane. The PTC is used to heat the oxygen permeable membrane. The PTC is electrically connected to the control component. When the PTC is turned on, the oxygen permeable membrane can separate oxygen from the air.

[0020] As a preferred technical solution, it comprises a plurality of PTCs, the plurality of PTCs are electrically connected to the control assembly, and the plurality of PTCs can be turned on individually or in combination.

[0021] As a preferred technical solution, it also includes a sensor assembly, which is electrically connected to the control assembly, and includes a temperature sensor, a pressure sensor, a flow sensor and an oxygen sensor for respectively detecting the gas temperature, air pressure, flow rate and oxygen concentration at the air inlet of the air compressor;

[0022] The obtaining of the actual oxygen flow rate at the air inlet of the air compressor specifically includes: obtaining the gas temperature, air pressure, flow rate and oxygen concentration at the air inlet of the air compressor detected by the sensor;

[0023] The actual oxygen flow rate at the air inlet of the air compressor is calculated according to the gas temperature, the gas pressure, the flow rate and the oxygen concentration.

[0024] As a preferred technical solution, the electric control valve is a three-way valve, and the three interfaces of the three-way valve are respectively connected to the first air inlet, the second air outlet and the air inlet of the air compressor.

[0025] As a preferred technical solution, the main air intake branch further includes a humidifier connected in series between the intercooler and the fuel cell stack.

[0026] As a preferred technical solution, the main air intake branch and the auxiliary air intake branch further include air filters, which are respectively arranged at the first air intake port and the second air intake port.

[0027] As a preferred technical solution, it also includes an outlet branch for discharging reactants after the reaction of the fuel cell stack, the air inlet end of the outlet branch is connected to the air outlet of the fuel cell stack, and the air outlet end is connected to the air outlet.

[0028] The present application also provides an electric vehicle, comprising the fuel cell system as described above.

[0029] A fuel cell system in the present application is provided with a main air intake branch and an auxiliary air intake branch, the main air intake branch includes an electric control valve, an air compressor, and an intercooler connected in series in sequence, the main air intake branch includes an oxygenator connected in series in sequence, the air intake ends of the main air intake branch and the auxiliary air intake branch are respectively connected to the air, and the air outlet ends are respectively connected to the air intake and the electric control valve of the fuel cell stack, the control component is respectively electrically connected to the fuel cell stack, the air compressor, the electric control valve, and the oxygen separator, and the speed of the air compressor, the opening of the electric control valve, and the opening and closing of the oxygen separation module are adjusted according to the difference between the actual oxygen demand flow at the air compressor inlet and the oxygen demand flow of the fuel cell stack measured; the present application adopts a single air compressor air intake system, which can meet the intake oxygen content requirements of the fuel cell stack under different altitude conditions, ensure the stable operation of the fuel cell stack, and improve the service life and reliability of the air compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present application is further described in detail below in conjunction with the accompanying drawings and preferred embodiments, but those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be used as a limitation on the scope of the present application. In addition, unless otherwise specified, the drawings are intended only to conceptually represent the composition or structure of the described objects and may contain exaggerated displays, and the drawings are not necessarily drawn to scale.

[0031] Figure 1 It is a structural schematic diagram of the present invention;

[0032] Figure 2 is a control flow chart of the present invention;

[0033] Figure 3 is a structural diagram of the oxygen separation module of the present invention;

[0034] Among them: 1. Battery stack; 11. Air inlet; 12. Air outlet; 2. Control component; 21. Flow sensor; 22. Temperature sensor; 23. Pressure sensor; 24. Oxygen sensor; 3. Main air intake branch; 31. First air inlet; 32. Electric control valve; 33. Air compressor; 34. Intercooler; 35. Humidifier; 36. Air filter; 4. Auxiliary air intake branch; 41. Second air inlet; 42. Oxygenator; 421. PTC; 422. Oxygen permeable membrane; 43. Oxygenator exhaust port. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0036] See also Figure 1-2 , a fuel cell system provided in an embodiment of the present application, comprising: a fuel cell stack 1, a main air intake branch 3, an auxiliary air intake branch 4 and a control component 2;

[0037] The main air intake branch 3 includes a main air intake pipe, and the two ends of the main air intake pipe are respectively a first air intake port 31 and a first air outlet, the first air outlet is connected to the air intake port 11 of the stack 1, and an electric control valve 32, an air compressor 33, and an intercooler 34 are sequentially arranged along the air intake direction of the main air intake pipe; air enters the air compressor 33 from the first air intake port 31 and is compressed by the air compressor 33, and then the high-temperature compressed gas enters the intercooler 34 through the pipeline, and enters the air intake port 11 of the stack 1 after cooling in the intercooler 34, so as to compensate for the oxygen flow of the stack 1 and prevent the high-temperature gas from affecting the performance of the stack 1. It should be noted that the air compressor 33 and the intercooler 34 in the embodiment of the present invention are both existing in the fuel cell system. The embodiment of the present invention effectively improves the oxygen intake of the vehicle in the plateau environment by utilizing the existing equipment of the fuel cell system and adding new devices, and has no effect on the existing air intake system pipeline of the fuel cell system.

[0038] The auxiliary air intake branch 4 includes an auxiliary air intake pipe, the two ends of the auxiliary air intake pipe are respectively a second air inlet 41 and a second air outlet, the second air outlet is connected to the electric control valve 32, and an aerator 42 is also arranged on the auxiliary air intake pipe, and an oxygen separation module is arranged in the aerator 42; air enters the aerator 42 from the second air inlet 41, and the oxygen separation module in the aerator 42 can selectively permeate oxygen, so that oxygen can pass through the oxygen separation module, while other gases cannot pass through, thereby purifying the oxygen in the air and adjusting the oxygen concentration of the branch.

[0039] The control component 2 is electrically connected to the fuel cell stack 1, the air compressor 33, the electric control valve 32, and the oxygen separation module, respectively, and the control component 2 is configured to:

[0040] Determine the oxygen demand flow rate of the fuel cell stack 1 according to the required power of the fuel cell stack 1;

[0041] Obtaining the actual oxygen flow rate at the air inlet of the air compressor 33;

[0042] According to the difference between the actual oxygen flow rate and the required oxygen flow rate, the rotation speed of the air compressor 33, the opening of the electric control valve 32 and the opening and closing of the oxygen separation module are adjusted.

[0043] In this embodiment, under different altitude conditions, the control component 2 calculates the oxygen demand flow rate of the fuel cell stack 1 based on the output power and the required power of the fuel cell stack 1, and then obtains the actual oxygen flow rate entering the air compressor 33, compares it with the oxygen demand flow rate of the fuel cell stack 1, and obtains the difference, and then adjusts the speed of the air compressor 33, the opening of the electric control valve 32 and the opening and closing of the oxygen separation module to perform oxygen compensation on the fuel cell stack 1.

[0044] Further, according to the actual oxygen demand flow rate and the difference between the oxygen demand flow rate, adjusting the speed of the air compressor 33, the opening of the electric control valve 32 and the opening and closing of the oxygen separation module specifically includes:

[0045] When the actual oxygen flow rate is equal to the required oxygen flow rate, the electric control valve 32 is switched so that the air inlet of the air compressor 33 is only connected to the first air inlet 31;

[0046] When the actual oxygen flow rate is less than the required oxygen flow rate, the method includes:

[0047] S1, increasing the rotation speed of the air compressor 33;

[0048] S2. When the speed of the air compressor 33 reaches the maximum value and the actual oxygen flow rate is still less than the required oxygen flow rate, the electric control valve 32 is switched so that the air inlet of the air compressor 33 is connected to the first air inlet 31 and the second air inlet 41 respectively;

[0049] S3. If the actual oxygen flow rate is still less than the required oxygen flow rate, start the oxygen separation module.

[0050] For further information, see Figure 3 The oxygen separation module includes a PTC 421 and an oxygen permeable membrane 422. The PTC 421 is used to heat the oxygen permeable membrane 422. The PTC 421 is electrically connected to the control component 2. When the PTC 421 is turned on, the oxygen permeable membrane 422 can separate oxygen from the air.

[0051] In this embodiment, the aerator 42 is also provided with an aerator exhaust port 43. When the PTC 421 is turned on to heat the oxygen permeable membrane 422, the oxygen permeable membrane 422 can selectively permeate the gas entering the aerator 42, so that oxygen enters the pipeline through the aerator 42, and the remaining gas is discharged through the aerator exhaust port 43.

[0052] Furthermore, it includes a plurality of PTC421, which are electrically connected to the control component 2, and the plurality of PTC421 can be turned on individually or in combination. In this embodiment, the PTC421 is divided into four pieces along the circumference of the inner cavity of the aerator 42, which respectively occupy 10%, 20%, 30%, and 40% of the inner surface area of ​​the inner cavity. The four PTC421 can be combined arbitrarily or work individually, and the oxygen permeation efficiency and oxygen permeation amount of the oxygen permeable membrane 422 can be changed by changing the temperature, so that the oxygen concentration entering the pipeline is changed, that is, the oxygen concentration requirement is achieved according to the oxygen compensation requirement under different working conditions.

[0053] Furthermore, it also includes a sensor assembly, which is electrically connected to the control assembly 2, and includes a temperature sensor 22, a pressure sensor 23, a flow sensor 21 and an oxygen sensor 24 for respectively detecting the gas temperature, pressure, flow rate and oxygen concentration at the air inlet of the air compressor 33;

[0054] The obtaining of the actual oxygen flow rate at the air inlet of the air compressor 33 specifically includes: obtaining the gas temperature, air pressure, flow rate and oxygen concentration at the air inlet of the air compressor 33 detected by the sensor;

[0055] The actual oxygen flow rate at the air inlet of the air compressor 33 is calculated based on the gas temperature, the gas pressure, the flow rate and the oxygen concentration.

[0056] It should be noted that, since the air quality may change due to changes in temperature and air pressure, adding a temperature sensor 22 makes the calculation result more accurate.

[0057] Furthermore, the electric control valve 32 is a three-way valve, and the three interfaces of the three-way valve are respectively connected to the first air inlet 31, the second air outlet and the air inlet of the air compressor 33. By controlling the different openings of the three-way valve, opening the air inlet of the air compressor 33 to connect to the air intake pipe, and then opening the main air intake branch 3 or the main and auxiliary air intake branches, the main air intake branch 3 or the main and auxiliary air intake branches 4 can be used to supply oxygen to the fuel cell stack 1.

[0058] Furthermore, the main intake branch 3 also includes a humidifier 35 connected in series between the intercooler 34 and the fuel cell stack 1 .

[0059] Furthermore, the main air intake branch 3 and the auxiliary air intake branch 4 further include an air filter 36, which is respectively arranged at the first air intake port 31 and the second air intake port 41. The air entering the first and second air intake ports is filtered by the air filter 36 to prevent gas with impurities from entering the air compressor 33 and the fuel cell stack 1, thereby affecting the normal operation of the air compressor 33 and the fuel cell stack 1.

[0060] Furthermore, it also includes an outlet branch for discharging the reactants after the reaction of the battery stack 1. The inlet end of the outlet branch is connected to the outlet 12 of the battery stack 1, and the outlet end is connected to the air outlet. The outlet branch is also connected to the humidifier 35. The gas of the inlet branch enters the battery stack 1 and undergoes a chemical reaction to produce water and gas. The water and gas flow out from the outlet 12 of the battery stack 1. When passing through the humidifier 35, the water can further moisten the gas entering the humidifier 35 from the inlet branch, and the gas passes through the humidifier 35 and is discharged through the outlet end.

[0061] The present application also provides an electric vehicle, comprising the fuel cell system as described above.

[0062] To summarize, the fuel cell system provided in this embodiment adopts a single air compressor intake system, and is provided with a main intake branch and an auxiliary intake branch. An oxygenator is provided on the auxiliary intake branch, and the connection between the two branches and the air compressor inlet is controlled by an electric control valve. The control strategy is set, and the control system can control the air compressor speed, the opening of the electric control valve and the opening and closing of the oxygenator. It can meet the intake oxygen content requirements of the fuel cell stack under different altitude conditions, ensure the stable operation of the fuel cell stack and the air compressor, and improve the service life and reliability of the air compressor.

[0063] This specification discloses the present application with reference to the accompanying drawings, and also enables those skilled in the art to implement the present application, including making and using any device or system, using suitable materials, and using any combined method. The scope of the present application is defined by the technical solution for protection, and includes other examples that occur to those skilled in the art. As long as such other examples include structural elements that are not different from the literal language of the technical solution for protection, or such other examples contain equivalent structural elements that are not substantially different from the literal language of the technical solution for protection, such other examples should be considered to be within the scope of protection determined by the technical solution for protection of the present application.

Claims

1. A fuel cell system, characterized in that: include: Fuel stack, main air intake branch, auxiliary air intake branch and control components; The main air intake branch comprises a main air intake pipe, the two ends of the main air intake pipe are respectively a first air intake port and a first air outlet, the first air outlet is connected to the air intake port of the fuel cell stack, and an electric control valve, an air compressor, and an intercooler are sequentially arranged along the air intake direction of the main air intake pipe; The auxiliary air intake branch comprises an auxiliary air intake pipe, the two ends of the auxiliary air intake pipe are respectively a second air intake port and a second air outlet, the second air outlet is communicated with the electric control valve, an oxygenator is also arranged on the auxiliary air intake pipe, and an oxygen separation module is arranged in the oxygenator; The control component is electrically connected to the fuel cell stack, the air compressor, the electric control valve, and the oxygen separation module, respectively, and the control component is configured to: Determine the oxygen demand flow rate of the fuel cell according to the required power of the fuel cell; Obtaining an actual oxygen flow rate at an air inlet of the air compressor; According to the difference between the actual oxygen flow rate and the required oxygen flow rate, the rotation speed of the air compressor, the opening of the electric control valve and the opening and closing of the oxygen separation module are adjusted.

2. The fuel cell system according to claim 1, characterized in that: According to the difference between the actual oxygen flow rate and the required oxygen flow rate, adjusting the speed of the air compressor, the opening of the electric control valve and the opening and closing of the oxygen separation module specifically includes: When the actual oxygen flow rate is equal to the required oxygen flow rate, switching the electronically controlled valve so that the air inlet of the air compressor is connected only to the first air inlet; When the actual oxygen flow rate is less than the required oxygen flow rate, the method includes: S1, increasing the rotation speed of the air compressor; S2. When the speed of the air compressor reaches the maximum value and the actual oxygen flow rate is still less than the required oxygen flow rate, the electric control valve is switched so that the air inlet of the air compressor is connected to the first air inlet and the second air inlet respectively; S3. If the actual oxygen flow rate is still less than the required oxygen flow rate, start the oxygen separation module.

3. The fuel cell system according to claim 1, characterized in that: The oxygen separation module includes a PTC and an oxygen permeable membrane. The PTC is used to heat the oxygen permeable membrane. The PTC is electrically connected to the control component. When the PTC is turned on, the oxygen permeable membrane can separate oxygen from the air.

4. The fuel cell system according to claim 3, characterized in that: It comprises a plurality of PTCs, which are electrically connected to the control component, and can be turned on individually or in combination.

5. The fuel cell system according to claim 1, characterized in that: Also includes a sensor assembly, the sensor assembly is electrically connected to the control assembly, the sensor assembly includes a temperature sensor, a pressure sensor, a flow sensor and an oxygen sensor for respectively detecting the gas temperature, air pressure, flow rate and oxygen concentration at the air inlet of the air compressor; The obtaining of the actual oxygen flow rate at the air inlet of the air compressor specifically includes: obtaining the gas temperature, air pressure, flow rate and oxygen concentration at the air inlet of the air compressor detected by the sensor; The actual oxygen flow rate at the air inlet of the air compressor is calculated according to the gas temperature, the gas pressure, the flow rate and the oxygen concentration.

6. The fuel cell system according to claim 1, characterized in that: The electric control valve is a three-way valve, and the three interfaces of the three-way valve are respectively connected to the first air inlet, the second air outlet and the air inlet of the air compressor.

7. The fuel cell system according to claim 1, characterized in that: The main air intake branch further includes a humidifier connected in series between the intercooler and the fuel cell stack.

8. The fuel cell system according to claim 1, characterized in that: The main air intake branch and the auxiliary air intake branch further include air filters, which are respectively arranged at the first air intake port and the second air intake port.

9. The fuel cell system according to claim 1, characterized in that: It also includes an air outlet branch for discharging reactants after the reaction of the fuel cell stack. The air inlet end of the air outlet branch is connected to the air outlet of the fuel cell stack, and the air outlet end is connected to the air outlet.

10. An electric vehicle, characterized in that: Comprising the fuel cell system as described in claims 1-9.

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