A proton exchange membrane fuel cell low-temperature starting system and starting method thereof

Abstract

The present invention provides a low-temperature starting system and method for a proton exchange membrane fuel cell. The system includes a fuel cell, a dummy cell, an air source, a hydrogen source, and a circulating water heating device. The dummy cell includes an end plate, a current collecting plate, a clamping plate, a bipolar plate, and a plastic electrode. The air outlets of the air source and the hydrogen source are both connected to the dummy cell anode air inlet pipeline. The dummy cell anode air outlet is connected to the fuel cell anode air inlet pipeline. The fuel cell anode air outlet is connected to the dummy cell cathode air inlet pipeline. The dummy cell cathode air outlet is connected to the fuel cell cathode air inlet pipeline. The circulating water heating device is connected to the dummy cell water cavity. The present invention can achieve rapid starting of a proton exchange membrane fuel cell in a lower temperature environment, effectively avoiding the problem of repeated phase changes during battery use that may reduce battery performance and lifespan.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a low-temperature starting system and a starting method for a proton exchange membrane fuel cell. Background Art

[0002] Proton exchange membrane fuel cells (PEMFCs) can directly convert chemical energy from fuel hydrogen and air into electrical energy. They boast high energy conversion efficiency and are pollution-free. They are considered a promising future transportation technology, contributing to my country's goals of energy conservation, emission reduction, and low-carbon development. PEMFCs are extremely complex systems, and their automotive applications inevitably present challenges such as storage and startup at low temperatures. In temperatures below 0°C, water is generated at the battery's cathode and transported outward. At this point, the water in the battery freezes, expanding by 9%. However, when the battery is activated, the waste heat melts the ice into water, reducing its volume. These repeated phase changes significantly impact the battery's material structure, performance, and lifespan.

[0003] In the existing technology, there are methods of heating the fuel cell stack from the inside through an auxiliary heating device, blowing hot air into the cathode to preheat the fuel cell stack, and a water-cooled fuel cell stack with an external circulating water heating system. On the one hand, the above methods are all direct heating of the fuel cell stack system. This heating method is not safe and gentle enough. Especially under the condition of large temperature difference, it is easy to cause temperature difference damage or deformation to the metal parts inside and outside the fuel cell stack system. In addition, the above methods all require the addition of other equipment or systems, which greatly increases the volume, quality and production cost of the fuel cell stack system, which is not conducive to the economic development of fuel cells.

[0004] In addition, there is also a method in the existing field of achieving low-temperature startup by heating the reaction gas in the fuel cell. The patent document with publication number CN110649283B discloses a fuel cell system and its low-temperature startup method, including: a fuel cell stack, a heat exchanger, a fuel supply system and an oxidant supply system. The fuel cell system uses the cathode gas supply temperature to preheat the cathode and anode of the fuel cell stack through a heat exchanger without increasing the system's excess energy consumption and fuel consumption, thereby achieving rapid startup of the fuel cell in a low-temperature environment; that is, the invention discloses the use of a heat exchanger to heat the gas to achieve low-temperature startup, However, the heat exchange principle of a heat exchanger usually consists of a sealed pipe and a heat transfer panel / heating tube. After the heat transfer panel is heated by a circuit system, two different media flow through the pipe. The heat transfer panel / heating tube transfers heat from one medium to the other to achieve heat exchange. Therefore, the structure, number, shape, position distribution and other designs of the heating panel / heating tube inside the heat exchanger determine the heat exchange uniformity and heat exchange effect of the heat exchanger. If any heating panel / heating tube is damaged, it will lead to uneven heat exchange, especially under the harsh conditions of low-temperature startup of fuel cells (such as -40°), which will seriously affect the stability of low-temperature startup. Summary of the Invention

[0005] In response to the technical problems raised above, a proton exchange membrane fuel cell low-temperature start-up system and a start-up method thereof are provided, which can realize rapid start-up of the proton exchange membrane fuel cell in a lower temperature environment, and has the characteristics of rapid and gentle temperature rise, uniform heat exchange, high stability of the low-temperature start-up process, and low production cost.

[0006] The technical means adopted in the present invention are as follows:

[0007] A low-temperature starting system for a proton exchange membrane fuel cell comprises: a fuel cell, a dummy battery, an air source, a hydrogen source and a circulating water heating device, wherein the dummy battery comprises an end plate, a current collecting plate, a clamping plate, a bipolar plate and a plastic electrode having the same size as the membrane electrode in the fuel cell, the gas outlets of the air source and the hydrogen source are both connected to the anode gas inlet of the dummy battery, the anode gas outlet of the dummy battery is connected to the anode gas inlet of the fuel cell, the anode gas outlet of the fuel cell is connected to the cathode gas inlet of the dummy battery, the cathode gas outlet of the dummy battery is connected to the cathode gas inlet of the fuel cell, and the circulating water heating device is cyclically connected to the water cavity of the dummy battery.

[0008] Furthermore, the bipolar plates of the fake battery include an anode plate and a cathode plate, and the flow field structures in the anode plate and the cathode plate are formed by a multi-channel S-shaped spine array. The S-shaped spines in the anode plate and the cathode plate are arranged alternately and staggered, and there is a gas flow channel between two adjacent S-shaped spines. The interior of the S-shaped spines has an inner cavity, and multiple inner cavities constitute the water cavity of the fake battery.

[0009] Furthermore, the air outlets of the air source and the hydrogen source are connected to the anode air inlet pipeline of the dummy battery through a three-way valve, and the pipelines connected to the air outlets of the air source and the hydrogen source are both provided with a pressure-stabilizing valve, a flow meter and a pressure gauge.

[0010] Furthermore, a thermocouple for temperature measurement is provided in the fuel cell, and the measuring range of the thermocouple is -60°C to 99°C.

[0011] Furthermore, the circulating water heating device adopts a water bath pot, the water outlet of the water bath pot is connected to the water inlet pipeline of the water cavity of the dummy battery, and the water outlet of the water cavity of the dummy battery is connected to the water inlet pipeline of the water bath pot.

[0012] The present invention also provides a method for starting a proton exchange membrane fuel cell low-temperature starting system, which performs low-temperature starting on the fuel cell when the temperature of the fuel cell stack is below 0 degrees Celsius, comprising the following steps:

[0013] Step 1. Start the water bath and set the water temperature so that hot water flows through the water bath outlet, passes through the water cavity inlet of the dummy battery, and then flows back to the water bath through the water cavity outlet of the dummy battery, forming a water cycle.

[0014] Step 2: Open the three-way valve, open each pressure regulating valve, and simultaneously open the air source and hydrogen source. Control the pressure of hydrogen and air through the pressure regulating valve and pressure gauge, and control the volume ratio between air and hydrogen through the flow meter.

[0015] Step 3, a mixture of hydrogen and air enters the dummy battery from the anode air inlet, is heated by the water circulation in the dummy battery, exits from the anode air outlet of the dummy battery, and then enters the fuel cell through the anode air inlet of the fuel cell for chemical reaction. The unreacted mixed gas is discharged from the anode air outlet of the fuel cell, and then enters the dummy battery again from the cathode air inlet of the dummy battery. At this time, the unreacted mixed gas is heated again by the dummy battery, discharged from the cathode air outlet of the dummy battery, and enters the fuel cell through the cathode air inlet of the fuel cell. The heated but unreacted mixed gas undergoes a chemical reaction inside the fuel cell again and is discharged from the cathode air outlet of the fuel cell.

[0016] Step 4: After the temperature of the fuel cell stack reaches above 0 degrees, switch the pipeline to allow hydrogen to enter the anode inlet of the fuel cell and air to enter the cathode inlet of the fuel cell to perform normal ventilation. At the same time, cooling water circulates in the water cavity of the fuel cell, the dummy battery stops using, and the fuel cell is started.

[0017] Furthermore, in step 1, the temperature of the water bath is 60-95°C.

[0018] Furthermore, in step 2, the volume of air accounts for 1-25% of the total volume of air and hydrogen; and the volume of hydrogen accounts for 75-99% of the total volume of air and hydrogen.

[0019] Furthermore, in step 2, the pressure values ​​on the pipelines connected to the gas outlets of the air source and the hydrogen source are equal, and the pressures of the hydrogen and air are consistent.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The system of the present invention proposes for the first time the use of dummy batteries to achieve preheating. Compared with other components or devices that can achieve heating, on the one hand, because the dummy batteries have the same structure and size as actual batteries and do not contain energy-consuming materials such as membrane electrodes, they can be integrated with the design and installation of the fuel cell stack in this system. In other words, the design of the dummy batteries of the present invention simplifies the battery structure of traditional heating methods and greatly reduces costs.

[0022] On the other hand, high-temperature water is circulated in the water cavity of the dummy battery to achieve preheating in the dummy battery. After the mixed gas is heated in the dummy battery, it directly enters the fuel cell to achieve low-temperature startup and a catalytic reaction. The catalytic reaction and the temperature are raised again. The two complement each other. Therefore, compared with the method of directly heating the fuel cell stack, the present invention directly heats the reaction gas. Therefore, this heating method is safer, gentler, and can achieve rapid heating.

[0023] Furthermore, since the dummy battery has the same bipolar plate as the fuel cell, the bipolar plate has a uniformly distributed flow field structure, and the flow field structure includes a water cavity for water flow. The present invention utilizes the coordination of the structural characteristics of the bipolar plate and the flow characteristics of the water flow to directly use the water flow as the heating medium to circulate at a uniform speed in the uniformly distributed flow field structure. This process will not be affected by major factors that affect the circulation of the water flow. Therefore, compared with the method of using a heat exchanger to electrically heat a solid and then use it as a heating medium, the present invention can better ensure the heating stability and uniformity of the mixed gas, thereby ensuring the stability of the low-temperature startup process.

[0024] On the other hand, since the bipolar plate flow field structure in the fake battery has the characteristics of uniform distribution, the mixed gas flowing in the flow field also has the characteristics of uniform flow speed and uniform gas distribution, and during this gas flow process, the gas is uniformly and continuously heated. Therefore, compared with other existing heating devices, the fake battery of the present invention has the advantage of more uniform gas heating. That is, the fake battery provided by the present invention can have a more uniform and stable heating mode in both gas and water flow compared with other existing heating devices, so it can effectively ensure stability during low-temperature startup.

[0025] 2. The bipolar plate structure of the present invention adopts an S-shaped flow channel. Compared with the straight-flow channel, the S-shaped flow channel has a certain "obstruction" effect on the gas and water flow, which can slightly reduce the flow rate of the gas and water flow in the dummy battery, thereby ensuring that the two fully interact with each other in the dummy battery to achieve heat exchange. Compared with other more complex flow channels, such as serpentine and annular, the S-shaped flow channel has sufficient fluidity to avoid the phenomenon that the gas and water flow circulate for a long time in each cycle in the dummy battery, resulting in large temperature changes before and after. In addition, the anode and cathode S-shaped flow channels of the bipolar plate of the present invention are spaced apart from each other, that is, for each gas channel, it is surrounded by the water flow channel, so that the gas can be fully exchanged with heat and the heat exchange efficiency is effectively improved.

[0026] 3. The system of the present invention can achieve preheating at the dummy battery before entering the fuel cell. At this time, the gas temperature rises. The higher the temperature, the more intense the reaction at the fuel cell membrane electrode, thereby improving the reaction efficiency. In a short period of time, the mixed gas releases more heat after reacting on the membrane electrode surface, avoiding water freezing due to insufficient heat generated by the catalytic reaction when starting at a lower temperature, causing water freezing inside the battery to damage the battery structure.

[0027] 4. The present invention has a simple structure and is based on a proton exchange membrane fuel cell main body device, and can achieve rapid startup without adding other auxiliary devices.

[0028] 5. The present invention has a fast starting speed and is improved on the cold starting method using catalytic reaction at the tail exhaust, thus solving the problem of low mixed gas temperature.

[0029] 6. The present invention has a low starting temperature. After the mixed gas passes through the dummy battery for heat exchange, its temperature rises and its activity becomes higher. After entering the fuel cell, it contacts the membrane electrode and undergoes a catalytic reaction, enabling rapid low-temperature starting.

[0030] 7. The present invention has low power consumption, the temperature of the mixed gas rises, the catalytic reaction effect is obvious, the heat released is greatly increased, and the hydrogen consumption of the catalytic reaction cold start is effectively reduced.

[0031] 8. The system of the present invention can better control the volume ratio, that is, control the explosion limit of hydrogen in the mixed gas in the air. In the same time, the flow rate and volume are constant, so the volume ratio in the actual mixed gas can be controlled by the flow rate of the flow meter.

[0032] Based on the above reasons, the present invention can be widely promoted in the fields of fuel cells and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0034] Figure 1 Schematic diagram of the pipeline connection of the system of the present invention.

[0035] Figure 2 Schematic diagram of the structure of the bipolar plate in the pseudo battery of the present invention.

[0036] Figure 3 Schematic diagram of another pipeline connection of the system of the present invention.

[0037] In the figure: 100, fuel cell; 200, dummy battery; 300, water bath; 400, air source; 500, hydrogen source; 600, pressure regulating valve; 700, flow meter; 800, first pipeline; 900, second pipeline; 1000, third pipeline; 1100, fourth pipeline;

[0038] 1. Anode plate; 2. Cathode plate; 3. S-shaped spine; 4. Inner cavity; 5. Gas flow channel. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0042] Unless otherwise specified, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments can have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0043] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0044] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0045] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0046] Example 1

[0047] The present invention provides a proton exchange membrane fuel cell low temperature starting system, which is mainly used in vehicle battery systems, such as Figure 1 As shown, the system of the present invention includes an air source 400, a hydrogen source 500, a fuel cell 100, a dummy battery 200 and a water bath 300. The air outlet of the air source 400 is connected to a first pipeline 800, and the air outlet of the hydrogen source 500 is connected to a second pipeline 900. The first pipeline 800 and the second pipeline 900 are connected to the anode air inlet pipeline of the dummy battery 200 after being connected through a three-way valve. At the same time, the second pipeline 900 of the hydrogen source 500 and the first pipeline 800 of the air source 400 are provided with a pressure-stabilizing valve 600, a flow meter 700, a pressure gauge, etc. for controlling pressure and flow. The anode gas outlet of the dummy battery 200 is connected to the anode gas inlet pipeline of the fuel cell 100. The anode gas outlet of the fuel cell 100 is connected to the cathode gas inlet pipeline of the dummy battery 200. The cathode gas outlet of the dummy battery 200 is connected to the cathode gas inlet pipeline of the fuel cell 100. The water outlet of the water bath 300 is connected to the water cavity water inlet pipeline of the dummy battery 200. The water cavity water outlet of the dummy battery 200 is connected to the water inlet pipeline of the water bath 300. The gas outlet of the air source 400 is also connected to the third pipeline 1000, which is connected to the cathode gas inlet pipeline of the fuel cell 100. The gas outlet of the hydrogen source 500 is also connected to the fourth pipeline 1100, which is connected to the anode gas inlet pipeline of the fuel cell 100. The water outlet of the water bath 300 is connected to the water cavity inlet pipeline of the fuel cell 100, and the water cavity outlet of the fuel cell 100 is connected to the water inlet pipeline of the water bath 300. Figure 3 shown.

[0048] The dummy battery 200 includes an end plate, a current collecting plate, a clamping plate, a bipolar plate, and a plastic electrode having the same size as the membrane electrode in the fuel cell 100. The bipolar plate in the dummy battery 200 includes an anode plate 1 and a cathode plate 2. Figure 2As shown, the flow field structures in both the anode plate 1 and the cathode plate 2 are formed by an array of multiple S-shaped spines 3. The multiple S-shaped spines 3 in the anode plate 1 and the cathode plate 2 are arranged in an alternating pattern. The S-shaped spines 3 have S-shaped cavities 4 within them. These cavities 4 on the anode plate 1 and cathode plate 2 form the water chamber channels of the dummy battery 200. S-shaped gas channels 5 are located between adjacent S-shaped spines 3. The gas channels 5 between the S-shaped spines 3 on the anode plate 1 form the anode gas channels of the dummy battery 200, while the gas channels 5 between the S-shaped spines 3 on the cathode plate 2 form the cathode gas channels of the dummy battery 200. A thermocouple with a temperature measurement range of -60°C to 99°C is installed within the fuel cell 100. Electronic on / off valves are installed on both the third and fourth pipelines 1000 and 1100 to control the flow of these channels. Electronic on / off valves are also installed on the inlet and outlet pipes connecting the water bath 300 and the fuel cell 100's water chamber. The present invention can realize rapid startup of the proton exchange membrane fuel cell in a lower temperature environment, effectively avoiding the problem of repeated phase changes during battery use that leads to reduced battery performance and life.

[0049] Example 2

[0050] Based on Example 1, the present invention further provides a method for starting a proton exchange membrane fuel cell low-temperature starting system, comprising the following steps:

[0051] S1. When the temperature of the fuel cell stack 100 is higher than 0 degrees, the pressure regulating valve 600 on the first pipeline 800 and the second pipeline 900 is closed, the three-way valve is closed, and the valves on the third pipeline 1000 and the fourth pipeline 1100 are opened. The hydrogen provided by the hydrogen source 500 enters the anode of the fuel cell 100, the air provided by the air source 400 enters the cathode of the fuel cell 100, and the circulating cooling water enters the water chamber of the fuel cell 100. The fuel cell stack 100 is started normally.

[0052] S2. When the temperature of the fuel cell stack 100 is lower than 0 degrees, the fuel cell 100 is started at low temperature:

[0053] S21. Before starting, open the water bath 300 and set the water temperature. The heated water flows through the water outlet of the water bath 300 and the water inlet of the dummy battery 200 into the water cavity of the dummy battery 200, and then flows back to the water bath 300 through the water outlet of the dummy battery 200, forming a water cycle. Set the circulating water temperature of the water bath 300 to 95°C.

[0054] S22. During startup, the valves on the third pipeline 1000 and the fourth pipeline 1100 are closed, the three-way valve is opened, the pressure regulating valve 600 on the first pipeline 800 and the second pipeline 900 are opened, and the air source 400 and the hydrogen source 500 are opened simultaneously. The pressure of the hydrogen is controlled to be consistent with that of the air by means of the pressure regulating valve 600 and the pressure gauge. The volume ratio of the air to the hydrogen is controlled by means of the flow meter 700 and other instruments. At this time, the volume of the air is 24% of the volume of the mixed gas, and the volume of the hydrogen is 76%;

[0055] S23, the mixed gas of hydrogen and air enters from the anode air inlet of the dummy battery 200, is heated by the water circulation in the dummy battery 200, comes out from the anode air outlet of the dummy battery 200, and then enters the fuel cell 100 through the anode air inlet of the fuel cell 100 for chemical reaction. At this time, the heated mixed gas can improve the catalytic reaction on the surface of the membrane electrode inside the fuel cell 100 and release a certain amount of heat. The unreacted mixed gas is discharged from the anode air outlet of the fuel cell 100 and then enters the dummy battery 200 again from the cathode air inlet of the dummy battery 200. At this time, the unreacted mixed gas is heated again by the dummy battery 200 and then discharged from the cathode air outlet of the dummy battery 200 and enters the fuel cell 100 through the cathode air inlet of the fuel cell 100. The heated but unreacted mixed gas effectively improves the catalytic reaction rate at the cathode of the membrane electrode of the fuel cell 100 and releases a certain amount of heat again, and is finally discharged from the cathode air outlet of the fuel cell 100;

[0056] S24. After the temperature of the fuel cell 100 stack reaches above 0 degrees, open the valves on the third pipeline 1000 and the fourth pipeline 1100, as well as the valve between the water bath 300 and the inlet and outlet of the water cavity of the fuel cell 100. By controlling the opening and closing of the pipeline valves, the pipeline is switched to allow hydrogen to enter the anode inlet of the fuel cell 100 and air to enter the cathode inlet of the fuel cell 100 for normal ventilation. At the same time, cooling water circulates in the water cavity of the fuel cell 100, the dummy battery 200 stops being used, and the startup of the fuel cell 100 is completed.

[0057] The system of the present invention can achieve preheating at the dummy battery before entering the fuel cell. At this time, the gas temperature rises. The higher the temperature, the more intense the reaction at the fuel cell membrane electrode. In a short period of time, the mixed gas releases more heat after reacting on the membrane electrode surface, avoiding water freezing due to insufficient heat generated by the catalytic reaction when starting at a lower temperature, causing water freezing inside the battery to damage the battery structure.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A proton exchange membrane fuel cell low temperature start-up system, characterized in that: include: A fuel cell (100), a dummy battery (200), an air source (400), a hydrogen source (500) and a circulating water heating device, wherein the dummy battery (200) comprises an end plate, a current collecting plate, a clamping plate, a bipolar plate and a plastic electrode having the same size as the membrane electrode in the fuel cell (100); the gas outlets of the air source (400) and the hydrogen source (500) are both connected to the anode gas inlet of the dummy battery (200); the anode gas outlet of the dummy battery (200) is connected to the anode gas inlet of the fuel cell (100); the anode gas outlet of the fuel cell (100) is connected to the cathode gas inlet of the dummy battery (200); the cathode gas outlet of the dummy battery (200) is connected to the cathode gas inlet of the fuel cell (100); and the circulating water heating device is cyclically connected to the water cavity of the dummy battery (200).

2. The low-temperature start-up system for a proton exchange membrane fuel cell according to claim 1, characterized in that: The bipolar plates of the dummy battery (200) include an anode plate (1) and a cathode plate (2), the flow field structures in the anode plate (1) and the cathode plate (2) are formed by an array of multiple S-shaped spines (3), the S-shaped spines (3) in the anode plate (1) and the cathode plate (2) are arranged in an alternating and staggered manner, a gas flow channel (5) is provided between two adjacent S-shaped spines (3), the interior of each S-shaped spine (3) has an inner cavity (4), and the multiple inner cavities (4) constitute the water cavity of the dummy battery (200).

3. The low-temperature start-up system for a proton exchange membrane fuel cell according to claim 1, characterized in that: The air outlets of the air source (400) and the hydrogen source (500) are connected to the anode air inlet pipeline of the dummy battery (200) through a three-way valve, and the pipelines connected to the air outlets of the air source (400) and the hydrogen source (500) are both provided with a pressure regulating valve (600), a flow meter (700) and a pressure gauge.

4. The low-temperature start-up system for a proton exchange membrane fuel cell according to claim 1, characterized in that: A thermocouple for temperature measurement is provided in the fuel cell (100), and the measuring range of the thermocouple is -60°C to 99°C.

5. The low-temperature start-up system for a proton exchange membrane fuel cell according to claim 1, characterized in that: The circulating water heating device adopts a water bath (300), the water outlet of the water bath (300) is connected to the water inlet pipeline of the water cavity of the dummy battery (200), and the water outlet of the water cavity of the dummy battery (200) is connected to the water inlet pipeline of the water bath (300).

6. A method for starting a proton exchange membrane fuel cell low-temperature starting system according to any one of claims 1 to 5, wherein when the temperature of the fuel cell (100) stack is lower than 0 degrees, the fuel cell (100) is started at low temperature, characterized in that: The steps include: Step 1: Before starting, open the water bath (300), set the water temperature, and allow hot water to flow into the water cavity of the dummy battery (200) through the water outlet of the water bath (300) and the water inlet of the dummy battery (200), and then flow back to the water bath (300) through the water outlet of the dummy battery (200), forming a water cycle; Step 2: When starting, open the three-way valve, open each pressure regulating valve (600), and simultaneously open the air source (400) and the hydrogen source (500). The pressure of hydrogen and air is controlled by the pressure regulating valve (600) and the pressure gauge, and the volume ratio between air and hydrogen is controlled by the flow meter (700). Step 3, the mixed gas of hydrogen and air enters from the anode air inlet of the dummy battery (200), is heated under the action of water circulation in the dummy battery (200), exits from the anode air outlet of the dummy battery (200), and then enters the fuel cell (100) through the anode air inlet of the fuel cell (100) to undergo a chemical reaction, the unreacted mixed gas is discharged from the anode air outlet of the fuel cell (100), and then enters the dummy battery (200) again from the cathode air inlet of the dummy battery (200), at this time, the unreacted mixed gas is heated again by the dummy battery (200), and then discharged from the cathode air outlet of the dummy battery (200) and enters the fuel cell (100) through the cathode air inlet of the fuel cell (100), the heated but unreacted mixed gas undergoes a chemical reaction again inside the fuel cell (100), and then is discharged from the cathode air outlet of the fuel cell (100); Step 4: After the temperature of the fuel cell (100) stack reaches above 0 degrees, the pipeline is switched to allow hydrogen to enter the anode inlet of the fuel cell (100) and air to enter the cathode inlet of the fuel cell (100) for normal ventilation. At the same time, cooling water circulates in the water cavity of the fuel cell (100), the dummy battery (200) is stopped, and the startup of the fuel cell (100) is completed.

7. The method for starting a proton exchange membrane fuel cell low-temperature starting system according to claim 6, characterized in that: In step 1, the temperature of the water bath (300) is 60-95°C.

8. The method for starting a proton exchange membrane fuel cell low-temperature starting system according to claim 6, characterized in that: In step 2, the volume of air accounts for 1-25% of the total volume of air and hydrogen; and the volume of hydrogen accounts for 75-99% of the total volume of air and hydrogen.

9. The method for starting a proton exchange membrane fuel cell low-temperature starting system according to claim 6, characterized in that: In step 2, the pressure values ​​on the pipelines connected to the air source (400) and the hydrogen source (500) are equal, and the pressure of hydrogen is consistent with that of air.

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