An air supply humidification and intercooling system for proton exchange membrane fuel cells

Abstract

The present invention discloses an air supply humidification intercooling system for a proton exchange membrane fuel cell. The system is connected to a fuel cell stack, and the fuel cell stack has a cooling circuit for circulating cooling water. The humidification intercooling system includes: a humidification intercooler, a humidification branch and an air-water separator. The humidification intercooler is connected to an air supply branch including an air filter and an air compressor, and is used to cool and humidify the air before entering the fuel cell stack. The humidification branch is connected to the outlet of the cooling water pump in the cooling circuit and the cooling water inlet of the humidification intercooler, and is used to transport cooling water to the humidification intercooler. The air-water separator is connected to the air outlet of the humidification intercooler and the air inlet of the stack. The present invention has both intercooling and humidification functions, does not need to be specially set up a humidification water circuit, and does not need electric control in the cooling and humidification links. It is suitable for high-power fuel cell systems and helps to significantly reduce system costs.

Description

Technical Field

[0001] The invention relates to a proton exchange membrane fuel cell, and in particular to an air supply humidification and intercooling system for a proton exchange membrane fuel cell. Background Art

[0002] Proton exchange membrane fuel cells (hereinafter referred to as fuel cells) have the advantages of high power density, high efficiency, low operating temperature and pollution-free products, making them very suitable for on-board use; and compared with pure electric vehicles with lithium-ion batteries as the main power, fuel cell vehicles can effectively solve the range anxiety problem and have great development prospects.

[0003] As an electrochemical power source, fuel cells require the cooperation of subsystems such as the air supply system, hydrogen supply system, and cooling system to work. Fuel cells are very sensitive to the internal water state. Internal water shortage will lead to: (1) dehydration of the proton exchange membrane, decreased proton conductivity, and increased ohmic impedance of the stack; (2) decreased catalytic activity of the catalyst layer and increased activation loss of the fuel cell. The accumulation of internal liquid water will hinder the diffusion of the reaction gas to the catalyst layer to participate in the reaction, which may cause the fuel cell to be flooded. Both water shortage and excess water will cause the performance of the fuel cell to decline, which shows that it is necessary to provide humidification for the fuel cell reaction gas, and the humidification must be appropriate.

[0004] At present, there are solutions to achieve internal self-humidification of the fuel cell stack by rationally designing the structure of the fuel cell stack and the flow field. The three-dimensional flow field design of the Toyota Mirai fuel cell stack belongs to internal humidification. However, the structural design is difficult, the process requirements are complex, there are many control variables, and the humidification effect is limited.

[0005] At present, there is also a liquid water spray humidification method, which is widely used in high-power fuel cell systems and can simultaneously humidify and cool the air. However, the current spray humidification system has obvious technical weaknesses, mainly including:

[0006] (1) Liquid water spray requires the construction of a separate water circuit. If the newly constructed water circuit is not heated, the humidification effect is poor; if the newly constructed water circuit is heated, the system structure is further complicated.

[0007] (2) The design of the internal structure of the spray chamber is not sufficiently considered, and the cooling and humidification effect is not ideal, which requires the control of the water spray volume; there is a large space for optimizing the chamber structure.

[0008] (3) Control the water level inside the humidifier. This can prevent malfunctions caused by excessive liquid water inside the humidifier, which complicates system control and reduces system reliability. Summary of the invention

[0009] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an air supply humidification intercooling system for a proton exchange membrane fuel cell.

[0010] The present invention provides an air supply humidification intercooling system for a proton exchange membrane fuel cell, which is connected to a fuel cell stack, wherein the fuel cell stack has a stack cooling water inlet, a stack cooling water outlet and a stack air inlet, and the fuel cell stack has a cooling circuit to circulate cooling water, wherein cooling water passes through a cooling water pump, enters the fuel cell stack from the stack cooling water inlet, enters a radiator through the stack cooling water outlet, and enters the stack cooling water inlet through the cooling water pump after heat dissipation to realize circulation, and the air supply humidification intercooling system comprises:

[0011] A humidifying intercooler connected to an air supply branch including an air filter and an air compressor, for cooling and humidifying the air before entering the fuel cell stack, the humidifying intercooler having a humidifying intercooler cooling water inlet, a humidifying intercooler air inlet and a humidifying intercooler air outlet;

[0012] a humidification branch, communicating with the outlet of the cooling water pump and the cooling water inlet of the humidification intercooler, for conveying cooling water to the humidification intercooler; and

[0013] An air-water separator is connected to the humidifying intercooler air outlet and the stack air inlet, and is used to separate liquid water in the humidified air, and has an air-water separator inlet, an air-water separator outlet and an air-water separator drain outlet;

[0014] The air passes through the air filter, the air compressor, the humidifying intercooler and the air-water separator in sequence, and enters the fuel cell stack from the stack air inlet to participate in the cathode reaction.

[0015] Furthermore, the flow rate of the cooling water pump is fixed, and the cooling water temperature is controlled by controlling the start and stop and the rotation speed of the cooling fan in the radiator, thereby ensuring that the water pressure at the outlet of the cooling water pump is constant.

[0016] Furthermore, in the air supply humidification intercooling system,

[0017] ΔP=P pump -P humidifier

[0018] ΔP is the pressure difference between the outlet pressure of the cooling water pump and the air pressure at the outlet of the nozzle of the inner cavity of the humidifying intercooler under the rated working state of the air supply humidifying intercooling system.

[0019] P pump is the cooling water pump outlet pressure,

[0020] Phumidifier is the air pressure at the outlet of the nozzle of the inner cavity of the humidifying intercooler under the rated working state of the air supply humidifying intercooling system,

[0021] If ΔP<1 bar, the air supply humidification intercooling system further comprises a booster water pump arranged before the cooling water inlet of the humidification intercooler;

[0022] If ΔP≥1 bar, the air supply humidification and intercooling system does not need to be equipped with the booster water pump.

[0023] Furthermore, the boost water pump has a boost water pump inlet and a boost water pump outlet, and the water pressure at the boost water pump outlet is kept constant to ensure that the water pressure at the cooling water inlet of the humidifying intercooler is constant.

[0024] Furthermore, the humidifying intercooler and the air-water separator are arranged in a vertical direction under normal working conditions, the air outlet of the humidifying intercooler is fixedly connected to the inlet of the air-water separator, and the water outlet of the air-water separator is vertically downward.

[0025] Furthermore, the humidifying intercooler comprises:

[0026] A housing having an air inlet for the humidifying intercooler and an air outlet for the humidifying intercooler;

[0027] A top cover, covering the top of the shell and fixedly connected to the shell;

[0028] A pressure atomizing nozzle is installed at the top cover and has an inlet and an outlet, wherein the inlet is the cooling water inlet of the humidifying intercooler; and

[0029] A guide fin is installed inside the shell and is located below the pressure atomizing nozzle.

[0030] Furthermore, the inlet and outlet pressures of the pressure atomizing nozzle are fixed to maintain a fixed spray water volume, and the minimum water volume is the saturated humidification water volume corresponding to the maximum air flow rate, and the calculation formula is:

[0031] In the formula,

[0032] The minimum spray water volume of the pressure atomizing nozzle, unit: g / s;

[0033] P sat,T is the saturated vapor pressure at the stack operating temperature T, unit: Pa;

[0034] P air,in is the air inlet pressure, unit: Pa;

[0035] It is the maximum air flow rate, unit: SLPM.

[0036] Furthermore, the guide fins are multiple in number and arranged in a staggered manner, so as to force the air to flow in a zigzag manner inside the humidifying intercooler, thereby extending the air movement length.

[0037] Furthermore, the air-water separator is a compressed air air-water separator to separate liquid water from the humidified air and ensure that the liquid water is automatically discharged without affecting the air pressure.

[0038] Furthermore, the liquid water accumulated inside the humidifying intercooler is discharged into the air-water separator under the action of air blowing and gravity, and is automatically discharged after being separated. The air-water separator also serves to remove the residual water in the inner cavity of the humidifying intercooler and to perform post-dehydration treatment of the humidified air.

[0039] The humidifying intercooler in the air supply humidification intercooling system of the present invention integrates effective humidification and intercooling functions, avoids the complex design of using an intercooler in addition to the humidifier, and simplifies the system structure; the present invention directly uses the cooling water circuit to provide liquid water for the humidifying intercooler, eliminates the complex water circuit added for the humidifying intercooler, simplifies the system structure of cooling water spray humidification, and provides a higher cooling water temperature at the outlet of the cooling water pump, which can enhance the humidification effect; the cooling and humidification links of the air supply humidification intercooling system of the present invention do not require any control, thereby improving the reliability of the system.

[0040] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0042] Figure 1 It is a schematic structural diagram of an air supply, humidification and intercooling system for a proton exchange membrane fuel cell according to an embodiment of the present invention;

[0043] Figure 2 yes Figure 1 Schematic diagram of the assembly structure of the humidifying intercooler and the air-water separator;

[0044] Figure 3 yes Figure 1 Schematic diagram of the structure of the humidifying intercooler.

[0045] Reference numerals:

[0046] 1 air filter,

[0047] 2 air compressors,

[0048] 3 humidifying intercooler,

[0049] 31 top cover, 32 pressure atomizing nozzle, 33 shell, 34 guide fin, 35 humidifying intercooler air inlet, 36 humidifying intercooler air outlet, 37 humidifying intercooler cooling water inlet,

[0050] 4. Gas-water separator,

[0051] 41 gas-water separator inlet, 42 gas-water separator outlet, 43 gas-water separator drain outlet,

[0052] 5 fuel cell stack,

[0053] 51: stack cooling water inlet, 52: stack air inlet, 53: stack cooling water outlet,

[0054] 6 Radiator,

[0055] 7 Cooling water pump,

[0056] 8 Booster water pump. DETAILED DESCRIPTION

[0057] 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 only used to explain the present invention, and cannot be understood as limiting the present invention.

[0058] Figure 1It is a schematic diagram of the structure of an air supply humidification intercooling system for a proton exchange membrane fuel cell according to an embodiment of the present invention. An air supply humidification intercooling system for a proton exchange membrane fuel cell is connected to a fuel cell stack 5, wherein the fuel cell stack 5 has a stack cooling water inlet 51, a stack cooling water outlet 53 and a stack air inlet 52, and the fuel cell stack 5 has a cooling circuit to circulate cooling water. Among them, cooling water passes through a cooling water pump 7, enters the fuel cell stack 5 from the stack cooling water inlet 51, enters the radiator 6 through the stack cooling water outlet 53, and enters the stack cooling water inlet 51 through the cooling water pump 7 after heat dissipation to realize circulation. The air supply humidification intercooling system includes: a humidification intercooler 3, a humidification branch and an air-water separator 4. The humidifying intercooler 3 is connected to the air supply branch including the air filter 1 and the air compressor 2, and is used to cool and humidify the air before entering the fuel cell stack 5. The humidifying intercooler 3 has a humidifying intercooler cooling water inlet 37, a humidifying intercooler air inlet 35 and a humidifying intercooler air outlet 36. The humidifying branch is connected to the outlet of the cooling water pump 7 and the humidifying intercooler cooling water inlet 37, and is used to transport cooling water to the humidifying intercooler 3. The air-water separator 4 is connected to the humidifying intercooler air outlet 36 and the stack air inlet 52, and is used to separate liquid water in the humidified air. It has an air-water separator inlet 41, an air-water separator outlet 42 and an air-water separator drain outlet 43. Among them, the air enters the humidifying intercooler 3 through the air filter 1 and the air compressor 2 in sequence. The humidifying intercooler 3 sprays liquid water, and the liquid water vaporizes while humidifying and cooling the air. After that, the humidified air passes through the gas-water separator 4 to remove the liquid water, and then enters the fuel cell stack 5 from the stack air inlet 52 to participate in the cathode reaction.

[0059] The air supply humidification intercooling system of the present invention adopts a spray humidification method to cool and humidify the high-heat and low-humidity air discharged from the air compressor 2. The humidifying intercooler integrates the effective humidification and intercooling functions, avoiding the complex design of using an intercooler in addition to the humidifier, and simplifying the system structure. The present invention directly uses the cooling water circuit to provide liquid water for the humidifying intercooler 3, eliminating the complex water circuit added for the humidifying intercooler 3, simplifying the system structure of the cooling water spray humidification, and the cooling water temperature at the outlet of the cooling water pump 7 is relatively high, which can enhance the humidification effect. The cooling and humidification links of the air supply humidification intercooling system of the present invention do not require any control, which improves the reliability of the system. The present invention is suitable for high-power fuel cell systems and helps to significantly reduce system costs.

[0060] Furthermore, if Figure 1 As shown, in this embodiment, the flow rate of the cooling water pump 7 is fixed, and the cooling water temperature is controlled by controlling the start and stop and the speed of the cooling fan in the radiator 6, so as to ensure that the water pressure at the outlet of the cooling water pump 7 is constant.

[0061] Furthermore, if Figure 1 As shown, in this embodiment, further, in the air supply humidification intercooling system,

[0062] ΔP=P pump -P humidifier

[0063] ΔP is the pressure difference between the outlet pressure of the cooling water pump 7 and the air pressure at the outlet of the nozzle of the inner cavity of the humidifying intercooler 3 under the rated working state of the air supply humidifying intercooling system.

[0064] P pump is the outlet pressure of the cooling water pump 7,

[0065] P humidifier is the air pressure at the outlet of the nozzle of the inner cavity of the humidifying intercooler 3 under the rated working state of the air supply humidifying intercooling system,

[0066] If ΔP<1 bar, the air supply humidification intercooling system further comprises a booster water pump 8 arranged before the cooling water inlet 37 of the humidification intercooler;

[0067] If ΔP≥1 bar, the air supply humidification intercooling system does not need to be equipped with the booster water pump 8. Furthermore, the booster water pump 8 has a booster water pump inlet and a booster water pump outlet, and the water pressure at the booster water pump outlet is kept constant to ensure that the water pressure at the humidification intercooler cooling water inlet 37 is constant.

[0068] Figure 2 yes Figure 1 Schematic diagram of the assembly structure of the humidifying intercooler and the air-water separator. Figure 3 yes Figure 1 Schematic diagram of the structure of the humidifying intercooler in FIG. Figure 2 , see also Figure 3 Furthermore, in this embodiment, the humidifying intercooler 3 and the air-water separator 4 are arranged in the vertical direction under normal working conditions, the air outlet 36 of the humidifying intercooler is fixedly connected to the air-water separator inlet 41, and the air-water separator drain outlet 43 is vertically downward. Furthermore, the air-water separator 4 is a compressed air air-water separator to separate the liquid water in the humidified air and ensure that the liquid water is automatically discharged without affecting the air pressure. Furthermore, the liquid water accumulated inside the humidifying intercooler 3 is discharged into the air-water separator 4 under the action of air purge and gravity, and is automatically discharged after being separated. The air-water separator 4 also serves to remove the residual water in the inner cavity of the humidifying intercooler 3 and the post-treatment of the humidified air dehydration.

[0069] In the present invention, the liquid water accumulated in the humidifying intercooler 3 is discharged into the air-water separator 4 by air purge and gravity. The air-water separator 4 simultaneously plays the role of removing the residual water in the humidifying intercooler 3 and post-processing the humidified air to remove water. There is no need to control the amount of liquid water in the humidifying intercooler 3, and the air supplied to the stack can be effectively prevented from containing liquid water. This simplifies the system structure and improves the system reliability.

[0070] Furthermore, the humidifying intercooler 3 includes: a shell 33, a top cover 31, a pressure atomizing nozzle 32 and a guide fin 34. The shell 33 is provided with the humidifying intercooler air inlet 35 and the humidifying intercooler air outlet 36. The top cover 31 covers the top of the shell 33 and is fixedly connected to the shell 33. In this embodiment, it is connected by fasteners. The pressure atomizing nozzle 32 is installed at the top cover 31, which has an inlet and an outlet. The inlet is the cooling water inlet 37 of the humidifying intercooler, and the outlet of the cooling water pump 7 is directly connected to the cooling water inlet 37 of the humidifying intercooler to supply liquid water to the pressure atomizing nozzle 32. The guide fin 34 is installed inside the shell 33 and is located below the pressure atomizing nozzle 32. In this embodiment, the liquid water of the pressure atomizing nozzle 32 comes from the cooling circuit, and the higher temperature of the cooling water is used to enhance the humidification effect.

[0071] Furthermore, if the head of the cooling water pump 7 cannot meet the nozzle atomization pressure requirement, the cooling water at the outlet of the cooling water pump 7 can be pressurized by the booster water pump 8 and flow to the pressure atomization nozzle 32. The inlet and outlet pressures of the pressure atomization nozzle 32 are fixed to maintain a fixed spray water volume. The minimum water volume is the saturated humidification water volume corresponding to the maximum air flow rate. The calculation formula is:

[0072] In the formula,

[0073] is the minimum spray water volume of the pressure atomizing nozzle 32, unit: g / s;

[0074] P sat,T is the saturated vapor pressure at the stack operating temperature T, unit: Pa;

[0075] P air,in is the air inlet pressure, unit: Pa;

[0076] It is the maximum air flow rate, unit: SLPM (standard liters per minute).

[0077] Furthermore, if Figure 3As shown, in this embodiment, the present invention redesigns the internal structure of the spray chamber of the pressure atomizing nozzle 32, and the number of the guide fins 34 is multiple and staggered to enhance the water-gas contact effect and assist heat dissipation, effectively enhancing the cooling and humidification performance. In specific implementation, the guide fins 34 are used to force the air to flow in a zigzag manner inside the humidifying intercooler 3 to extend the air movement length. The guide fins 34 are used to enhance the formation of internal vortices, use the vortices to effectively retain water, and enhance the water-gas contact effect. The guide fins 34 are used to enhance the convective heat exchange effect of the humidifying intercooler 3 and assist heat dissipation.

[0078] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0079] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An air supply humidification and intercooling system for a proton exchange membrane fuel cell, characterized in that: Connected to the fuel cell stack, the fuel cell stack has a stack cooling water inlet, a stack cooling water outlet and a stack air inlet, the fuel cell stack has a cooling circuit to circulate cooling water, wherein the cooling water passes through a cooling water pump, enters the fuel cell stack from the stack cooling water inlet, enters the radiator through the stack cooling water outlet, and enters the stack cooling water inlet through the cooling water pump after heat dissipation to realize circulation, the air supply humidification intercooling system includes: A humidifying intercooler connected to an air supply branch including an air filter and an air compressor, for cooling and humidifying the air before entering the fuel cell stack, the humidifying intercooler having a humidifying intercooler cooling water inlet, a humidifying intercooler air inlet and a humidifying intercooler air outlet; a humidification branch, communicating with the outlet of the cooling water pump and the cooling water inlet of the humidification intercooler, for conveying cooling water to the humidification intercooler; and An air-water separator is connected to the humidifying intercooler air outlet and the stack air inlet, and is used to separate liquid water in the humidified air, and has an air-water separator inlet, an air-water separator outlet and an air-water separator drain outlet; The air passes through the air filter, the air compressor, the humidifying intercooler and the air-water separator in sequence, and enters the fuel cell stack from the stack air inlet to participate in the cathode reaction; ΔP=P pump -P humidifier ΔP is the pressure difference between the outlet pressure of the cooling water pump and the air pressure at the outlet of the nozzle of the inner cavity of the humidifying intercooler under the rated working state of the air supply humidifying intercooling system. P pump is the cooling water pump outlet pressure, P humidifier is the air pressure at the outlet of the nozzle of the inner cavity of the humidifying intercooler under the rated working state of the air supply humidifying intercooling system, If ΔP<1 bar, the air supply humidification intercooling system further comprises a booster water pump arranged before the cooling water inlet of the humidification intercooler; If ΔP ≥ 1 bar, the air supply humidification and intercooling system does not need to be equipped with the booster water pump; The humidifying intercooler and the air-water separator are both arranged in the vertical direction under normal working conditions, the air outlet of the humidifying intercooler is fixedly connected with the inlet of the air-water separator, and the water outlet of the air-water separator is vertically downward.

2. The air supply humidification and intercooling system according to claim 1, characterized in that: The flow rate of the cooling water pump is fixed, and the cooling water temperature is controlled by controlling the start and stop and the speed of the cooling fan in the radiator, so as to ensure that the water pressure at the outlet of the cooling water pump is constant.

3. The air supply humidification and intercooling system according to claim 1, characterized in that: The boost water pump has a boost water pump inlet and a boost water pump outlet. The water pressure at the boost water pump outlet is kept constant to ensure that the cooling water inlet water pressure of the humidifying intercooler is constant.

4. The air supply humidification and intercooling system according to claim 1, characterized in that: The humidifying intercooler comprises: A housing having an air inlet for the humidifying intercooler and an air outlet for the humidifying intercooler; A top cover, covering the top of the shell and fixedly connected to the shell; A pressure atomizing nozzle is installed at the top cover and has an inlet and an outlet, wherein the inlet is the cooling water inlet of the humidifying intercooler; and The guide fin is installed inside the shell and is located below the pressure atomizing nozzle.

5. The air supply humidification and intercooling system according to claim 4, characterized in that: The inlet and outlet pressures of the pressure atomizing nozzle are fixed to maintain a fixed spray water volume. The minimum water volume is the saturated humidification water volume corresponding to the maximum air flow rate. The calculation formula is: The minimum spray water volume of the pressure atomizing nozzle, unit: g / s; P sat,T is the saturated vapor pressure at the stack operating temperature T, unit: Pa; P air,in is the air inlet pressure, unit: Pa; It is the maximum air flow rate, unit: SLPM.

6. The air supply humidification and intercooling system according to claim 4, characterized in that: The guide fins are multiple in number and arranged in a staggered manner, so as to force the air to flow in a zigzag manner inside the humidifying intercooler, thereby extending the air movement length.

7. The air supply humidification and intercooling system according to claim 1, characterized in that: The air-water separator is a compressed air air-water separator, which is used to separate liquid water from the humidified air and ensure that the liquid water is automatically discharged without affecting the air pressure.

8. The air supply humidification and intercooling system according to any one of claims 1 to 7, characterized in that: The liquid water accumulated inside the humidifying intercooler is discharged into the air-water separator under the action of air purge and gravity, and is automatically discharged after being separated. The air-water separator also serves to remove the residual water in the inner cavity of the humidifying intercooler and to perform post-dehydration treatment of the humidified air.

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