Air supply system and fuel cell including same

Abstract

The utility model provides an air supply system and a fuel cell comprising the same, the air supply system is used for supplying air to a fuel cell stack, the air supply system comprises an air inlet pipeline and an exhaust pipeline, an inlet of the air inlet pipeline is communicated with an external air source and is communicated with an inlet of the stack through an air compressor, an intercooler and a humidifier in sequence; an outlet of the electric pile is communicated with an exhaust pipeline, and after the exhaust pipeline passes through a humidifier, an outlet of the exhaust pipeline is communicated with the external environment; the outlet of the air compressor further communicates with an anti-surge valve, the air inlet end and the air outlet end of the anti-surge valve communicate with the first air outlet end and the air inlet end of the air compressor correspondingly, and the first air outlet end communicates with the air inlet pipeline. When surge occurs, the anti-surge valve is opened, and the anti-surge valve and the air compressor form a loop. According to the air supply system, the distance between the surge generation source and the anti-surge functional part is shortened, and the anti-surge response speed is increased. And meanwhile, released high-pressure air is recycled, the working efficiency of the air compressor is improved, and the structure of the anti-surge branch is simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an air supply system and a fuel cell comprising the same. Background Art

[0002] A fuel cell is a device that generates electricity through an electrochemical reaction between hydrogen and oxygen in the air under the action of a catalyst. It includes a stack and a casing. The stack is encapsulated in the casing with a certain gap between the two. Hydrogen and oxygen are introduced into the stack and generate electricity through an electrochemical reaction under the action of a catalyst. The stack is made up of a number of bipolar plates and membrane electrodes stacked repeatedly. Due to problems such as the stacking process and the accumulation of component tolerances, a small amount of hydrogen in the stack will leak into the packaging shell of the stack. If it is not purged in time to disperse, it is very easy to cause the fuel cell to explode during operation. In addition, in the actual use environment, changes in temperature and humidity will cause condensation in the packaging shell, which will cause insulation to decrease and even trigger insulation fault alarms.

[0003] When a fuel cell is working, auxiliary subsystems such as the air supply system, hydrogen supply system, thermal management system, stack system, and electrical system are required to work together effectively to generate electricity.

[0004] Among them, the air supply system supplies the fuel cell stack with the air required for its electrical energy reaction and meets the air flow, pressure, temperature and humidity requirements of the fuel cell at different power levels. At the same time, it also ensures that the unreacted air and generated water are smoothly discharged into the atmosphere.

[0005] Usually, the air supply system includes devices such as air compressors and humidifiers. The air compressor is used to pressurize the external air, and the humidifier is used to increase the humidity of the pressurized gas to obtain an air source that meets the system operation requirements. Among them, the air compressor is the core component of the air supply system. The air compressors used for fuel cells mainly include Roots, centrifugal, vortex, screw and other types. Centrifugal air compressors have advantages in noise, efficiency, volume and other aspects, and have become the mainstream products in the market. However, an important feature of air compressors such as centrifugal air compressors is that when the air compressor works at low flow and high pressure ratio, it is easy to surge. When a centrifugal air compressor surges, it will cause a series of chain reactions such as uncontrollable air flow, loud noise, high vibration and temperature rise. In severe cases, it may also damage the centrifugal air compressor and affect the life of the fuel cell stack; therefore, when the centrifugal air compressor enters the surge area, it is necessary to release the centrifugal air compressor from the surge area.

[0006] The existing anti-surge technical solutions have disadvantages such as slow anti-surge response speed. Utility Model Content

[0007] The technical problem to be solved by the utility model is to overcome the defect of slow response speed of the air supply system of the fuel cell in the prior art when surge occurs, and to provide an air supply system and a fuel cell comprising the same.

[0008] The utility model solves the above technical problems through the following technical solutions:

[0009] An air supply system for supplying air to a fuel cell stack, comprising an intake pipeline and an exhaust pipeline, wherein the inlet of the intake pipeline is connected to an external air source, passes through an air compressor, an intercooler and a humidifier in sequence, until it is connected to the inlet of the stack; the outlet of the stack is connected to the exhaust pipeline, and after the exhaust pipeline passes through the humidifier, its outlet is connected to the external environment;

[0010] The air supply system also includes an anti-surge valve, the air inlet end of the anti-surge valve is connected to the first air outlet end of the air compressor, the air outlet end of the anti-surge valve is connected to the air inlet end of the air compressor, and the first air outlet end is connected to the air inlet pipeline; when surge occurs, the anti-surge valve opens to form a loop with the air compressor.

[0011] In this solution, the air supply system connects the air inlet and outlet of the anti-surge valve to the first outlet and inlet of the air compressor, respectively, to form an anti-surge branch, thereby shortening the distance between the surge source (air compressor) and the anti-surge functional component (anti-surge valve) and improving the anti-surge response speed. During surge, the pressure in the air compressor can be quickly released, thereby quickly releasing the air compressor from the surge zone to achieve the anti-surge effect. At the same time, the released high-pressure air is recycled to improve the working efficiency of the air compressor. The anti-surge valve directly connects the air inlet and outlet of the air compressor, which also simplifies the structure of the anti-surge branch.

[0012] Preferably, the air supply system further comprises a first bypass branch, one end of which is connected to the intercooler, and the other end of which is connected to the gap cavity between the outer shell of the fuel cell and the fuel cell stack.

[0013] In this solution, one end of the first bypass branch is connected to the intercooler, and the other end is connected to the gap cavity between the outer shell of the fuel cell and the stack, so that part of the air cooled by the intercooler can enter the gap cavity through the first bypass branch for purging, taking out part of the heat generated during the operation of the stack, and also taking out a small amount of hydrogen leaked from the hydrogen cavity to the packaging shell during the operation of the stack, preventing hydrogen from accumulating, avoiding the risk of explosion, and improving the safety of system operation. At the same time, the air at a certain temperature entering the gap cavity can also purge and remove the condensation in the outer shell, ensuring the insulation performance, avoiding the triggering of the insulation fault alarm, making the overall operation of the fuel cell stable, and reducing the failure rate.

[0014] Preferably, the humidifier comprises at least two inlets and at least two outlets, the first inlet and the first outlet of the humidifier are arranged on the intake pipeline, the first inlet of the humidifier is communicated with the intercooler, and the first outlet of the humidifier is communicated with the inlet of the fuel cell stack;

[0015] The second inlet and the second outlet of the humidifier are arranged on the exhaust pipeline, and the second inlet of the humidifier is connected to the outlet of the fuel cell stack.

[0016] In this solution, the air inlet and exhaust pipes are connected respectively through two groups of inlet and outlet combinations of the humidifier (the first inlet and the first outlet constitute the first inlet and outlet combination, and the second inlet and the second outlet constitute the second inlet and outlet combination), and a connecting loop is formed between the humidifier and the stack, so that the water vapor generated by the electric energy reaction of the stack (i.e., hydrogen and oxygen generate electric energy through electrochemical reaction under the action of a catalyst) flows back to the humidifier through the second inlet, so as to increase the humidity of the dry air entering from the first inlet, so as to provide a gas with a certain humidity, which is conducive to the electrochemical reaction of generating electric energy in the stack. This solution makes full use of the water vapor generated by the stack itself for humidification, without the need for other humidification equipment, which is conducive to simplifying the structure and improving energy utilization.

[0017] Preferably, the exhaust pipeline is further provided with a confluence pipe for converging the exhausted air and discharging it from its outlet end, including an interface communicating with the second outlet of the humidifier.

[0018] In this solution, the exhaust gas discharged from the humidifier is collected by the above-mentioned manifold and discharged to the external environment in a centralized manner instead of being discharged in a dispersed manner, thereby avoiding pollution to other equipment or the environment and protecting the equipment from damage caused by the exhaust gas (for example, damage caused by high temperature or corrosion).

[0019] Preferably, the air supply system further comprises a second bypass branch, one end of which is in communication with the gap cavity between the housing of the fuel cell and the fuel cell stack, and the other end of which is in communication with the manifold.

[0020] In this solution, the second bypass branch is connected to the manifold through the above-mentioned arrangement, and the hydrogen and condensed water vapor blown out from the second bypass branch are collected and discharged centrally from the manifold.

[0021] Preferably, a back pressure valve is further provided between the manifold and the second outlet of the humidifier.

[0022] In this solution, the back pressure valve provided above can adjust the gas pressure and flow rate flowing in the pipeline of the air supply system, so as to maintain the intake pressure and flow rate required for the gas reaction in the fuel cell stack; at the same time, the gas with excessive pressure is discharged to cut off or throttle the pipeline.

[0023] Preferably, a muffler is provided at the outlet of the manifold.

[0024] In this solution, the noise of the air supply system is reduced by a silencer.

[0025] Preferably, the air compressor is a centrifugal air compressor, and the second air outlet end of the centrifugal air compressor is connected to the manifold.

[0026] In this solution, the incoming air can be pressurized by a centrifugal air compressor. Compared with other types of air compressors, the use of a centrifugal air compressor is beneficial to reducing noise, improving pressurization efficiency, and reducing equipment size.

[0027] A fuel cell comprises the air supply system as described above.

[0028] In this solution, the fuel cell is directly connected to the anti-surge valve at the outlet of the air compressor through the above-mentioned air supply system, which shortens the distance between the surge source (air compressor) and the anti-surge functional component (anti-surge valve) and improves the anti-surge response speed. The outlet of the anti-surge valve is connected to any one of the intake pipeline, exhaust pipeline and external environment, which can quickly release the pressure in the air compressor during surge to achieve the anti-surge effect.

[0029] The positive progress of the utility model is that the air supply system and the fuel cell including the same shorten the distance between the surge source (air compressor) and the anti-surge functional component (anti-surge valve) by directly connecting the anti-surge valve at the outlet of the air compressor, thereby improving the anti-surge response speed. The outlet of the anti-surge valve is connected to any one of the intake pipeline, the exhaust pipeline and the external environment, so that the pressure in the air compressor can be quickly released during surge, thereby achieving the anti-surge effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure of the air supply system of Example 1 of the utility model.

[0031] Description of reference numerals:

[0032] Battery stack 1

[0033] Entrance 2 of the battery stack

[0034] The outlet of the battery stack 3

[0035] Housing 4

[0036] Ventilation Inlet 5

[0037] Ventilation outlet 6

[0038] Intake pipe 7

[0039] Exhaust pipe 8

[0040] Air filter 9

[0041] Air flow meter 10

[0042] Air compressor 11

[0043] Air bearing outlet pipe 12,

[0044] Intercooler 13

[0045] Humidifier 14

[0046] First inlet 15 of the humidifier

[0047] The first outlet 16 of the humidifier

[0048] Second inlet 17 of humidifier

[0049] Second outlet 18 of the humidifier

[0050] Anti-surge valve 19

[0051] First bypass branch 20

[0052] Second bypass branch 21

[0053] Manifold 22

[0054] Back pressure valve 23

[0055] Silencer 24

[0056] Pressure sensor 25

[0057] First temperature sensor 26

[0058] Second temperature sensor 27

[0059] Hydrogen concentration sensor 28 DETAILED DESCRIPTION

[0060] A preferred embodiment is given below, and the present invention is described more clearly and completely in conjunction with the accompanying drawings.

[0061] Example 1

[0062] This embodiment provides an air supply system for supplying the fuel cell stack 1 with air required for electrical energy reaction.

[0063] like Figure 1As shown, the air supply system includes an intake pipeline 7 and an exhaust pipeline 8. The inlet of the intake pipeline 7 is connected to an external air source. The external air passes through an air filter 9, an air flow meter 10, an air compressor 11, an intercooler 13 and a humidifier 14 in sequence until it is connected to the inlet 2 of the stack. The air filter 9 filters the air, and the filtered clean air is measured by the air flow meter 10 to obtain the flow rate of the intake pipeline 7. Then the air compressor 11 pressurizes the air. The pressurized air is cooled by the intercooler 13 to protect the equipment from damage caused by high temperature, which is beneficial to the stability and life of the equipment. The cooled air enters the humidifier 14 for humidification treatment. After these treatments, an air source that meets the system operation requirements is obtained, and then enters the stack 1. The oxygen in the air is mixed with the hydrogen introduced into the stack 1 from the outside, and electric energy is generated through electrochemical reaction under the action of the catalyst. In this embodiment, the air compressor 1111 is specifically an oil-free centrifugal air compressor. The outlet 3 of the fuel cell stack is connected to the exhaust pipe 8, and after the exhaust pipe 8 passes through the humidifier 14, its outlet is connected to the external environment.

[0064] The air supply system also includes an anti-surge valve 19, an air inlet end of the anti-surge valve 19 is connected to the first air outlet end of the air compressor 11 on the air inlet pipeline 7, an air outlet end of the anti-surge valve 19 is connected to the air inlet end of the air compressor 11, and the first air outlet end of the air compressor 11 is connected to the air inlet pipeline 7; when surge occurs, the anti-surge valve 19 opens to form a loop with the air compressor 11, and the pressure in the air compressor 11 is quickly released, thereby quickly releasing the air compressor 11 from the surge zone, thereby achieving the anti-surge effect.

[0065] The air supply system directly connects the inlet and outlet of the anti-surge valve 19 to the inlet and outlet of the air compressor 11, forming a directly connected anti-surge branch, shortening the distance between the surge source (air compressor 11) and the anti-surge functional component (anti-surge valve 19), and improving the anti-surge response speed. While achieving the anti-surge effect, the anti-surge branch recycles the released high-pressure air, improving the working efficiency of the air compressor 11. In addition, the anti-surge valve 19 is directly connected to the inlet and outlet of the air compressor 11, which also simplifies the structure of the anti-surge branch.

[0066] Among them, the air supply system also includes a first bypass branch 20, one end of the first bypass branch 20 is connected to the intercooler 13, and the other end is connected to the ventilation inlet 5 on the fuel cell housing 4, and then connected to the gap cavity between the fuel cell housing 4 and the stack 1, so that part of the air with suitable humidity and temperature after cooling by the intercooler 13 can enter the gap cavity through the first bypass branch 20 for purging, taking out part of the heat generated during the operation of the stack 1, and also taking out a small amount of hydrogen leaked from the hydrogen cavity to the packaging shell during the operation of the stack 1, preventing hydrogen from accumulating, avoiding explosion hazards, and improving the safety of system operation. At the same time, the air at a certain temperature entering the gap cavity can also purge and remove the condensation in the housing 4, ensure the insulation performance, avoid triggering the insulation fault alarm, make the overall operation of the fuel cell stable, and reduce the failure rate.

[0067] The humidifier 14 includes two inlets and at least two outlets. The first inlet 15 and the first outlet 16 of the humidifier are arranged on the air intake pipeline 7. The first inlet 15 of the humidifier is connected to the intercooler 13, and the first outlet 16 of the humidifier is connected to the inlet 2 of the fuel cell stack. The cooled dry air enters the humidifier 14 from the first inlet, is humidified in the humidifier 14, and the wet air enters the fuel cell stack 1 from the first outlet. Therefore, the first inlet is a dry inlet, and the first outlet is a wet outlet.

[0068] The second inlet 17 and the second outlet 18 of the humidifier are arranged on the exhaust pipe 8, and the second inlet 17 of the humidifier is connected to the outlet 3 of the fuel cell stack. The second outlet 18 of the humidifier is connected to the external environment. Hydrogen and oxygen in the fuel cell stack 1 generate electrical energy through electrochemical reaction under the action of the catalyst. At the same time, the chemical reaction will also generate heat, so high-temperature water vapor and unreacted air will be discharged from the outlet 3 of the fuel cell stack. In this way, the high-level water vapor discharged from the outlet 3 of the fuel cell stack will flow back to the humidifier 14 again and mix with the dry air entering from the first inlet 15 of the humidifier to increase the humidity of the air.

[0069] The two inlet and outlet combinations of the humidifier 14 (the first inlet 15 and the first outlet 16 constitute the first inlet and outlet combination, and the second inlet 17 and the second outlet 18 constitute the second inlet and outlet combination) are respectively connected to the intake pipeline 7 and the exhaust pipeline 8, and a communication loop is formed between the humidifier 14 and the stack 1, so that the water vapor generated by the electric energy reaction of the stack 1 (that is, hydrogen and oxygen generate electric energy through electrochemical reaction under the action of the catalyst) flows back to the humidifier 14 through the second inlet 17, so as to increase the humidity of the dry air entering from the first inlet 15, so as to provide a gas with a certain humidity, which is conducive to the electrochemical reaction of generating electric energy in the stack 1. In other embodiments, if there is a separate humidifier 14 outside the air supply system, it is not necessary to return the water vapor discharged from the outlet of the stack 1 to the humidifier 14 to achieve the humidification function. At this time, the outlet 3 of the stack can also be directly connected to the external environment or connected to the external environment through a separate pipeline. However, this embodiment makes full use of the water vapor generated by the stack 1 itself for humidification, without the need for other humidification equipment, which is conducive to simplifying the structure and improving energy utilization.

[0070] Among them, a pressure sensor 25 and a first temperature sensor 26 are also installed between the humidifier 14 and the inlet 2 of the fuel cell stack to measure the pressure and temperature of the air entering the fuel cell stack 1 respectively; a second temperature sensor 27 is also installed between the humidifier 14 and the outlet 3 of the fuel cell stack to measure the exhaust temperature of the fuel cell stack 1.

[0071] like Figure 1 As shown, the exhaust pipe 8 is also provided with a manifold 22 for converging the exhausted air and discharging it from its outlet end, including an interface communicating with the second outlet 18 of the humidifier. The outlet of the manifold 22 is communicated with the external environment.

[0072] By adopting the manifold 22 arranged in this way, the exhaust gas discharged from the humidifier 14 is collected and discharged to the external environment in a centralized manner rather than being discharged in a dispersed manner, thereby avoiding pollution to other equipment or the environment and protecting the equipment from damage caused by the exhaust gas (for example, damage caused by high temperature or corrosion).

[0073] like Figure 1 As shown, the air supply system also includes a second bypass branch 21, one end of which is connected to the ventilation outlet 6 of the fuel cell housing 4, and then connected to the gap cavity between the fuel cell housing 4 and the stack 1, and the other end is connected to the manifold 22, and the hydrogen and condensed water vapor blown out from the second bypass branch 21 are collected and discharged from the manifold 22. The air flowing in the stack packaging housing 4 flows out from the ventilation outlet 6 through the second bypass branch 21. A hydrogen concentration sensor 28 is also installed on the second bypass branch 21, which can detect the change of hydrogen concentration inside the stack packaging shell in real time and online. Once the hydrogen concentration exceeds the upper limit, a fault is reported or the machine is shut down for processing. The outflowing air is then collected by the manifold 22 and discharged into the atmosphere.

[0074] like Figure 1 As shown, a back pressure valve 23 is also provided between the manifold 22 and the second outlet 18 of the humidifier. The back pressure valve 23 provided in this way can adjust the gas pressure and flow rate flowing in the pipeline of the air supply system, so that the intake pressure and flow rate required for the gas reaction in the fuel cell stack 1 can be maintained; at the same time, the gas with excessive pressure is discharged, which plays a role of cutting off or throttling in the pipeline. When working, the back pressure valve 23 is coupled and controlled with the air flow meter 10 and the oil-free centrifugal air compressor 11 to provide the fuel cell stack 1 with air of suitable flow rate and pressure.

[0075] like Figure 1 As shown, the outlet of the manifold 22 is provided with a muffler 24 and then communicated to the external environment. The muffler 24 reduces the noise of the air supply system.

[0076] In other embodiments, the oil-free centrifugal air compressor 11 may also use other types of boosting equipment or other types of centrifugal air compressors 11. However, compared with other types of air compressors 11, the centrifugal air compressor 11 used in this embodiment is more conducive to reducing noise, improving boosting efficiency, and reducing equipment size while achieving air boosting.

[0077] The oil-free centrifugal air compressor 11 includes an air bearing (not shown in the figure), and a second air outlet of the air compressor is provided on the air bearing, and the second air outlet includes an air outlet interface, and the air outlet interface is connected to the manifold 22 through the air bearing outlet pipe. The air discharged from the air outlet interface has a high temperature and a relatively low pressure, and is not suitable as an air source for the operation of the fuel cell stack 1. Therefore, it is guided to the manifold 22 through the air bearing outlet pipe to be discharged, so as to ensure that effective gas enters the fuel cell stack 1.

[0078] Example 2

[0079] This embodiment provides a fuel cell, which includes auxiliary subsystems such as the air supply system, hydrogen supply system, thermal management system, fuel cell stack system, electrical system, etc. in Embodiment 1.

[0080] The fuel cell adopts the air supply system of Example 1, and directly connects the anti-surge valve 19 at the outlet of the air compressor 11, thereby shortening the distance between the surge source (air compressor 11) and the anti-surge functional component (anti-surge valve 19), and improving the anti-surge response speed. The outlet of the anti-surge valve 19 is connected to any one of the intake pipeline 7, the exhaust pipeline 8 and the external environment, so that the pressure in the air compressor 11 can be quickly released during surge, thereby achieving the anti-surge effect.

[0081] Although the specific implementations of the utility model are described above, those skilled in the art should understand that this is only an example, and the protection scope of the utility model is defined by the attached claims. Those skilled in the art can make various changes or modifications to these implementations without departing from the principle and essence of the utility model, but these changes and modifications fall within the protection scope of the utility model.

Claims

1. An air supply system for supplying air to a fuel cell stack, comprising an air intake line and an exhaust line, The inlet of the air intake pipeline is connected to an external air source, passes through an air compressor, an intercooler and a humidifier in sequence, and finally connects to the inlet of the fuel cell stack; the outlet of the fuel cell stack is connected to the exhaust pipeline, and after the exhaust pipeline passes through the humidifier, its outlet is connected to the external environment; It is characterized in that It also includes an anti-surge valve, the air inlet end of the anti-surge valve is connected to the first air outlet end of the air compressor, the air outlet end of the anti-surge valve is connected to the air inlet end of the air compressor, and the first air outlet end is connected to the air inlet pipeline; when surge occurs, the anti-surge valve opens to form a loop with the air compressor.

2. The air supply system according to claim 1, characterized in that The air supply system further includes a first bypass branch, one end of which is connected to the intercooler, and the other end of which is connected to the gap cavity between the housing of the fuel cell and the fuel cell stack.

3. The air supply system according to claim 1, characterized in that The humidifier comprises at least two inlets and at least two outlets, the first inlet and the first outlet of the humidifier are arranged on the intake pipeline, the first inlet of the humidifier is communicated with the intercooler, and the first outlet of the humidifier is communicated with the inlet of the fuel cell stack; The second inlet and the second outlet of the humidifier are arranged on the exhaust pipeline, and the second inlet of the humidifier is connected to the outlet of the fuel cell stack.

4. The air supply system according to claim 3, characterized in that The exhaust pipeline is also provided with a confluence pipe for converging the exhausted air and discharging it from its outlet end, and includes an interface connected to the second outlet of the humidifier.

5. The air supply system according to claim 4, characterized in that The air supply system further includes a second bypass branch, one end of which is in communication with the gap cavity between the housing of the fuel cell and the fuel cell stack, and the other end of which is in communication with the manifold.

6. The air supply system according to claim 4, characterized in that A back pressure valve is also provided between the manifold and the second outlet of the humidifier.

7. The air supply system according to claim 4, characterized in that The outlet of the manifold is provided with a muffler.

8. The air supply system according to claim 4, characterized in that The air compressor is a centrifugal air compressor, and the second air outlet end of the centrifugal air compressor is connected to the manifold.

9. A fuel cell, characterized in that: The fuel cell comprises an air supply system as claimed in any one of claims 1 to 8 above.

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