Underwater equipment, fuel cell system and purging method thereof

Abstract

The invention relates to underwater equipment, a fuel cell system and a purging method of the fuel cell system. The fuel cell system comprises: a blind-end hydrogen-oxygen fuel cell stack; the hydrogen conveying structure, the first gas passage and the first discharge pipeline are respectively arranged at two ends of the blind-end hydrogen-oxygen fuel cell stack, and the first on-off valve is arranged on the first gas passage; the oxygen conveying structure, the second gas passage and the second discharge pipeline are respectively arranged at two ends of the blind-end hydrogen-oxygen fuel cell stack; the second on-off valve is arranged on the second gas passage; and when the fuel cell system is shut down, the purging structure can supply purging gas to the first gas passage and the second gas passage, and the purging gas is stored in the mounting space of the fuel cell system in advance. Therefore, no residual hydrogen and oxygen exist in the blind-end hydrogen-oxygen fuel cell stack after purging, the blind-end hydrogen-oxygen fuel cell stack is prevented from being in a high-voltage open-circuit state for a long time, and a nitrogen cylinder for providing purging gas does not need to be specially carried.

Description

Technical Field

[0001] The present application relates to the technical field of underwater fuel cell safety management, and in particular to an underwater device, a fuel cell system and a purging method thereof. Background Art

[0002] At present, hydrogen-oxygen fuel cells use hydrogen as fuel and oxygen as oxidant, and directly convert the chemical energy of the fuel into electrical energy through electrochemical reactions. They are not limited by the Carnot cycle, and have a power generation efficiency of up to 50% to 60%. The only reaction product is water, making them green and efficient, making them an energy conversion system with broad prospects.

[0003] Generally, the application scenarios of hydrogen and oxygen fuel cells are mainly road vehicles and cogeneration stationary power generation. However, in special segments, hydrogen and oxygen fuel cells are more suitable as the power system of UUV (Underwater Unmanned Vehicle). Compared with lithium-ion power systems, they have the advantages of high power density, long driving range, and light weight; compared with gas engine power systems, they have the advantages of low vibration and noise, and almost no tail exhaust.

[0004] In enclosed underwater scenarios, the small size and narrow internal space of the unmanned submersible place high demands on the spatial layout and power generation efficiency of the fuel cell system.

[0005] In order to improve the power generation efficiency, the fuel cell system needs to reduce the power consumption of accessories as much as possible. The dead-end hydrogen and oxygen fuel cell (Dead-end PEMFC) configuration is suitable for fuel cell systems with smaller output power. It directly adopts the technical route of reduced pressure supply of high-pressure hydrogen and high-pressure oxygen bottles, no gas circulation, and reaction water discharge by gravity, eliminating the use of gas circulation pumps and greatly reducing system energy consumption.

[0006] However, there is also a disadvantage, that is, when the fuel cell system is shut down, the gas circulation pump cannot be used for gas purge, which causes the fuel cell stack to be in a high-voltage open circuit state for a long time, causing irreversible damage to the membrane electrode such as carbon corrosion and platinum oxidation. In addition, in order to improve the internal space utilization of hydrogen and oxygen fuel cell unmanned submersibles and maximize the cruising range, sufficient space is usually reserved for fuel carrying space for high-pressure hydrogen and high-pressure oxygen bottles, and no nitrogen bottles are carried for shutdown purge gas supply, which affects the shutdown purge of the fuel cell system. Summary of the invention

[0007] Based on this, it is necessary to provide an underwater equipment, a fuel cell system and a purging method thereof to address the problem that the hydrogen and oxygen fuel cells currently used in underwater equipment cannot be shut down for purging. The method can prevent the blind-end hydrogen and oxygen fuel cell stack from being in a high-voltage open-circuit state for a long time, thereby ensuring the performance and life of the blind-end hydrogen and oxygen fuel cell stack. At the same time, there is no need to carry a special nitrogen bottle to provide purging gas, thereby reducing the volume and structural complexity of the fuel cell system.

[0008] A fuel cell system, comprising:

[0009] Blind-end hydrogen-oxygen fuel cell stack;

[0010] A hydrogen delivery structure, comprising a first gas passage, a first on-off valve and a first exhaust pipeline, wherein the first gas passage and the first exhaust pipeline are respectively arranged at two ends of the blind-end hydrogen-oxygen fuel cell stack, and the first on-off valve is arranged in the first gas passage;

[0011] an oxygen delivery structure, comprising a second gas passage, a second on-off valve and a second exhaust pipeline, wherein the second gas passage and the second exhaust pipeline are respectively arranged at two ends of the blind-end hydrogen-oxygen fuel cell stack, and the second on-off valve is arranged in the second gas passage;

[0012] The purge structure is connected to at least the first gas passage and the second gas passage. When the fuel cell system is shut down, the purge structure can supply purge gas to the first gas passage and the second gas passage. The purge gas is pre-stored in the installation space of the fuel cell system.

[0013] In one embodiment of the present application, the purge structure includes a purge pump, a first purge component, and a second purge component;

[0014] The first purge assembly is connected to the first gas passage and the second gas passage, and is located between the first on-off valve and the blind-end hydrogen-oxygen fuel cell stack;

[0015] The second purge assembly is connected to the first exhaust pipeline and the second exhaust pipeline;

[0016] The purge pump is connected to the first purge assembly and controls the first purge assembly and the second purge assembly to purge at least one of the first gas passage and the second gas passage.

[0017] In one embodiment of the present application, the first purge assembly includes a first connecting pipeline, a first control valve and a second control valve, the first connecting pipeline connects the first gas passage and the second gas passage, the first control valve and the second control valve are arranged in the first connecting pipeline at intervals, and the purge pump is connected between the first control valve and the second control valve;

[0018] The second purge assembly includes a second connecting pipeline, a third control valve, a fourth control valve and a third exhaust pipeline. The second connecting pipeline connects the first exhaust pipeline and the second exhaust pipeline. The third control valve and the fourth control valve are spaced apart in the second connecting pipeline. The third exhaust pipeline is connected to the second connecting pipeline.

[0019] In one embodiment of the present application, the fuel cell system includes at least one of the following features:

[0020] In the first item, the purge structure uses air as the purge gas, and the purge pump first purges the second gas passage through the first purge component and the second purge component, and then purges the first gas passage and the second gas passage at the same time;

[0021] Alternatively, the purge structure uses nitrogen as the purge gas, and the purge pump simultaneously purges the first gas passage and the second gas passage through the first purge component and the second purge component;

[0022] Second, the hydrogen delivery structure further includes two first temperature and pressure detection components, which are respectively disposed in the first gas passage and the first exhaust pipeline, and are disposed close to the blind-end hydrogen-oxygen fuel cell stack;

[0023] The oxygen delivery structure further includes two second temperature and pressure detection components, which are respectively arranged in the second gas passage and the second exhaust pipeline, and are arranged close to the blind-end hydrogen and oxygen fuel cell stack;

[0024] Item 3, the hydrogen delivery structure further comprises a first pressure detection member, the first pressure detection member is arranged in the first gas passage and is located between the first on-off valve and the first purge assembly;

[0025] The oxygen delivery structure further includes a second pressure detection member, which is disposed in the second gas passage and located between the second on-off valve and the first purge assembly;

[0026] Fourthly, the hydrogen delivery structure further comprises a first separator and a first drain valve, wherein the first drain valve is arranged in the first discharge pipeline and is located on a side of the second purge assembly away from the blind end hydrogen-oxygen fuel cell stack, and the first separator is arranged in the first discharge pipeline and is located between the second purge assembly and the first drain valve;

[0027] The oxygen delivery structure further includes a second separator and a second drain valve, wherein the second drain valve is disposed in the second discharge pipeline and is located on a side of the second purge assembly away from the blind-end hydrogen-oxygen fuel cell stack, and the second separator is disposed in the second discharge pipeline and is located between the second purge assembly and the second drain valve;

[0028] Item 5, the fuel cell system further includes a hydrogen removal structure, and the hydrogen removal structure is connected to the third exhaust pipeline of the second purge assembly.

[0029] In one embodiment of the present application, the first purge assembly further includes a first regulating valve and a second regulating valve, wherein the first regulating valve is disposed in the first gas passage and is located between the first purge assembly and the blind-end hydrogen-oxygen fuel cell stack;

[0030] The second regulating valve is arranged in the second gas passage and is located between the first purge assembly and the blind-end hydrogen-oxygen fuel cell stack.

[0031] A purging method for a fuel cell system is applied to a fuel cell system as described in any of the above technical features, and the purging method comprises at least the following steps:

[0032] Obtaining a shutdown instruction of the fuel cell system;

[0033] Control the hydrogen delivery structure and the oxygen delivery structure to close, and stop delivering hydrogen and oxygen;

[0034] Determining whether the purge gas in the installation space where the fuel cell system is located is air;

[0035] If yes, control the purge structure to first purge the oxygen delivery structure, and then purge the hydrogen delivery structure and the oxygen delivery structure at the same time;

[0036] If not, controlling the purge structure to purge the hydrogen delivery structure and the oxygen delivery structure simultaneously;

[0037] Circularly purging the hydrogen delivery structure and the oxygen delivery structure;

[0038] Obtaining a single-chip voltage of a blind-end hydrogen-oxygen fuel cell stack, and determining whether the single-chip voltage is within a preset range;

[0039] If so, controlling the purge structure to stop purge;

[0040] If not, continue to circulate and purge the hydrogen delivery structure and the oxygen delivery structure;

[0041] The single chip voltage is an average single chip voltage and / or a maximum single chip voltage.

[0042] In one embodiment of the present application, controlling the purge structure to first purge the oxygen delivery structure, and then simultaneously purge the hydrogen delivery structure and the oxygen delivery structure, comprises the following steps:

[0043] Close the first control valve and the third control valve, and open the second control valve and the fourth control valve;

[0044] Turning on the purge pump, adjusting the rotation speed of the purge pump and the duty cycle of the second regulating valve to purge the oxygen delivery structure;

[0045] Obtaining a first pressure of gas in the hydrogen delivery structure, and determining whether the first pressure is less than or equal to a first set threshold;

[0046] If yes, open the first control valve and the third control valve;

[0047] If not, continue to regulate the rotation speed of the purge pump and the duty cycle of the second regulating valve to purge the oxygen delivery structure.

[0048] In one embodiment of the present application, controlling the purge structure to purge the hydrogen delivery structure and the oxygen delivery structure simultaneously comprises the following steps:

[0049] Open the first control valve, the third control valve, the second control valve, and the fourth control valve;

[0050] The purge pump is turned on, and the rotation speed of the purge pump is adjusted.

[0051] In one embodiment of the present application, cyclically purging the hydrogen delivery structure and the oxygen delivery structure comprises the following steps:

[0052] Regulating the duty ratio of the first regulating valve and the second regulating valve;

[0053] Controlling the pressure in the oxygen delivery structure and the pressure in the hydrogen delivery structure to be equal and less than a second set threshold;

[0054] Control the purge pump to purge at a first speed for a first preset time, purge at a second speed for a second preset time, and then purge at the first speed for the first preset time, and purge in sequence in a cycle;

[0055] The first rotational speed is different from the second rotational speed.

[0056] An underwater device, comprising an underwater host and a fuel cell system as described in any one of the above technical features;

[0057] The fuel cell system is arranged on the underwater host and provides power for the underwater host.

[0058] After adopting the above technical solution, this application has at least the following technical effects:

[0059] The underwater equipment, fuel cell system and purge method of the present application, in which the first gas passage in the hydrogen delivery structure is connected to the first exhaust pipeline at both ends of the blind-end hydrogen and oxygen fuel cell stack, and the first on-off valve controls the on-off of the first gas passage. The second gas passage in the oxygen delivery structure is connected to the second exhaust pipeline at both ends of the blind-end hydrogen and oxygen fuel cell stack, and the second on-off valve controls the on-off of the second gas passage. The purge structure can at least connect the first gas passage and the second gas passage to supply purge gas to the first gas passage and the second gas passage, and the purge gas is pre-stored in the installation space of the fuel cell system.

[0060] When the fuel cell system is shut down, the purge structure can pass the purge gas into the first gas passage and the second gas passage, and then the purge gas can discharge hydrogen from the first gas passage, the blind-end hydrogen and oxygen fuel cell stack, the first exhaust pipeline and the purge structure, and discharge oxygen from the second gas passage, the blind-end hydrogen and oxygen fuel cell stack, the second exhaust pipeline and the purge structure. After the blind-end hydrogen and oxygen fuel cell stack is purged after shutdown, there will be no residual hydrogen and oxygen in the blind-end hydrogen and oxygen fuel cell stack, avoiding irreversible damage such as carbon corrosion and platinum oxidation to the membrane electrode, thereby avoiding the blind-end hydrogen and oxygen fuel cell stack from being in a high-voltage open-circuit state for a long time, ensuring the performance and life of the blind-end hydrogen and oxygen fuel cell stack. At the same time, the purge structure uses the gas pre-stored in the installation space of the fuel cell system as the purge gas, without the need to carry a nitrogen bottle specifically for providing the purge gas, reducing the volume and structural complexity of the fuel cell system. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG. 1 is a schematic diagram of a fuel cell system according to an embodiment of the present application.

[0062] FIG. 2 is a schematic diagram of the fuel cell system shown in FIG. 1 , illustrating a purge structure.

[0063] FIG. 3 is a partial schematic diagram of the fuel cell system at point A shown in FIG. 1 .

[0064] FIG. 4 is a partial schematic diagram of the fuel cell system at point B shown in FIG. 1 .

[0065] FIG. 5 is a schematic diagram of the flow of purge gas in the fuel cell system shown in FIG. 1 .

[0066] FIG. 6 is a purge flow chart of the fuel cell system shown in FIG. 5 .

[0067] Wherein: 100, fuel cell system; 110, blind end hydrogen and oxygen fuel cell stack; 120, hydrogen delivery structure; 102, hydrogen path; 121, first gas path; 122, first on-off valve; 123, first discharge pipeline; 124, high pressure hydrogen bottle; 125, first temperature and pressure detection component; 126, first pressure detection component; 127, first separator; 128, first drain valve; 130, oxygen delivery structure; 103, oxygen path; 131, second gas path; 132, second on-off valve; 133, second discharge pipeline; 134, high pressure oxygen bottle; 135. Second temperature and pressure detection component; 136. Second pressure detection component; 137. Second separator; 138. Second drain valve; 140. Purge structure; 141. Purge pump; 142. First purge assembly; 1421. First connecting pipeline; 1422. First control valve; 1423. Second control valve; 1424. First regulating valve; 1425. Second regulating valve; 143. Second purge assembly; 1431. Second connecting pipeline; 1432. Third control valve; 1433. Fourth control valve; 1434. Third discharge pipeline; 150. Hydrogen removal structure. DETAILED DESCRIPTION

[0068] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0069] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0070] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0071] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0072] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "on" or "below" a second feature, etc., or the like, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0073] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0074] Understandably, in underwater closed scenarios, fuel cell systems are used in unmanned submersibles to power unmanned submersibles. In order to improve power generation efficiency, the dead-end hydrogen and oxygen fuel cell (Dead-end PEMFC) configuration is usually suitable for fuel cell systems with lower output power. However, when the fuel cell system is shut down, the gas circulation pump cannot be used for gas purge, causing the fuel cell stack to be in a high-voltage open circuit state for a long time, which will cause irreversible damage to the membrane electrode. In addition, in order to improve the internal space utilization of hydrogen and oxygen fuel cell unmanned submersibles, nitrogen bottles used for shutdown purge gas are usually not carried, which affects the shutdown purge of the fuel cell system.

[0075] To this end, referring to FIG. 1 , the present application provides a novel fuel cell system 100. FIG. 1 is a schematic diagram of a fuel cell system 100 of an embodiment of the present application. The fuel cell system 100 is mainly used in underwater equipment to supply power to the underwater main body of the underwater equipment to ensure that the underwater equipment operates in a water environment. Optionally, the underwater equipment includes but is not limited to unmanned submersibles, and can also be other equipment that needs to use the fuel cell system 100 underwater.

[0076] The fuel cell system 100 can purge the blind-end hydrogen-oxygen fuel cell stack 110 after shutdown, thereby preventing the blind-end hydrogen-oxygen fuel cell stack 110 from being in a high-voltage open-circuit state for a long time, thereby ensuring the performance and life of the blind-end hydrogen-oxygen fuel cell stack 110. At the same time, there is no need to carry a special nitrogen bottle to provide purge gas, thereby reducing the volume and structural complexity of the fuel cell system 100.

[0077] The specific structure of the fuel cell system 100 according to one embodiment is introduced below.

[0078] Referring to FIGS. 1 to 4 , in one embodiment, a fuel cell system 100 includes a blind-end hydrogen-oxygen fuel cell stack 110, a hydrogen delivery structure 120, an oxygen delivery structure 130, and a purge structure 140. The hydrogen delivery structure 120 includes a first gas passage 121, a first on-off valve 122, and a first exhaust pipeline 123. The first gas passage 121 and the first exhaust pipeline 123 are respectively arranged at two ends of the blind-end hydrogen-oxygen fuel cell stack 110, and the first on-off valve 122 is arranged in the first gas passage 121. The oxygen delivery structure 130 includes a second gas passage 131, a second on-off valve 132, and a second exhaust pipeline 133. The second gas passage 131 and the second exhaust pipeline 133 are respectively arranged at two ends of the blind-end hydrogen-oxygen fuel cell stack 110, and the second on-off valve 132 is arranged in the second gas passage 131.

[0079] The purge structure 140 is at least connected to the first gas passage 121 and the second gas passage 131. When the fuel cell system 100 is shut down, the purge structure 140 can supply purge gas to the first gas passage 121 and the second gas passage 131. The purge gas is pre-stored in the installation space of the fuel cell system 100. FIG2 is a schematic diagram of the fuel cell system 100 shown in FIG1 showing the purge structure 140, FIG3 is a partial schematic diagram of the fuel cell system 100 shown in FIG1 at A, and FIG4 is a partial schematic diagram of the fuel cell system 100 shown in FIG1 at B.

[0080] The blind-end hydrogen-oxygen fuel cell stack 110 is the main component of the fuel cell system 100 where the electrochemical reaction occurs. The blind-end hydrogen-oxygen fuel cell stack 110 uses a plurality of monolithic cells stacked in series to form a whole. The blind-end hydrogen-oxygen fuel cell stack 110 uses hydrogen as fuel and oxygen as an oxidant. Hydrogen enters the interior of the blind-end hydrogen-oxygen fuel cell stack 110 through the anode of the blind-end hydrogen-oxygen fuel cell stack 110. Under the action of the catalyst, hydrogen atoms become protons after losing electrons at the anode, and the protons pass through the membrane electrode inside the blind-end hydrogen-oxygen fuel cell stack 110 to reach the cathode.

[0081] At the same time, the electrons reach the cathode through the external circuit of the blind-end hydrogen-oxygen fuel cell stack 110. On the cathode side, protons, electrons and oxygen combine to form liquid water, thereby generating current. After hydrogen and oxygen undergo an electrochemical reaction in the blind-end hydrogen-oxygen fuel cell stack 110, liquid water can be generated, and the liquid water is discharged through the flow channel inside the blind-end hydrogen-oxygen fuel cell stack 110.

[0082] Moreover, the blind-end hydrogen-oxygen fuel cell stack 110 means that the stoichiometric ratio of the amount of hydrogen introduced into the anode and the amount of oxygen introduced into the cathode is 1, and the pressure on the anode side is slightly higher than the pressure on the cathode side. In this way, hydrogen and oxygen undergo electrochemical reactions in the blind-end hydrogen-oxygen fuel cell stack 110 according to the hydrogen oxidation chemical reaction molar ratio, without the circulation of hydrogen and oxygen, and without the power consumption of the circulation components, so as to improve the system efficiency of the fuel cell system 100.

[0083] The blind-end hydrogen-oxygen fuel cell stack 110 has a first channel and a second channel inside, the first channel is used to transport hydrogen and generated liquid water, and the second channel is used to transport oxygen and generated liquid water. It is worth noting that the focus of this application is to use the purge structure 140 to purge the blind-end hydrogen-oxygen fuel cell stack 110, and the specific structure of the blind-end hydrogen-oxygen fuel cell stack 110 and the principle of electrochemical reaction are prior art and will not be repeated in the following text.

[0084] The hydrogen delivery structure 120 is a structure for delivering hydrogen and discharging liquid water. Specifically, in the hydrogen delivery structure 120, the first gas passage 121 and the first discharge pipeline 123 are respectively arranged at the two ends of the blind-end hydrogen-oxygen fuel cell stack 110, the first gas passage 121 is connected to the hydrogen inlet end of the blind-end hydrogen-oxygen fuel cell stack 110, and the first discharge pipeline 123 is connected to the hydrogen outlet end of the blind-end hydrogen-oxygen fuel cell stack 110. That is, the first gas passage 121, the first channel of the blind-end hydrogen-oxygen fuel cell stack 110, and the first discharge pipeline 123 are connected to form the hydrogen path 102. The first on-off valve 122 is arranged in the first gas passage 121 to control the on-off of the first gas passage 121.

[0085] The oxygen delivery structure 130 is a structure for delivering oxygen and discharging liquid water. Specifically, in the oxygen delivery structure 130, the second gas passage 131 and the second discharge pipeline 133 are respectively arranged at the two ends of the blind-end hydrogen and oxygen fuel cell stack 110, the second gas passage 131 is connected to the oxygen inlet end of the blind-end hydrogen and oxygen fuel cell stack 110, and the second discharge pipeline 133 is connected to the oxygen outlet end of the blind-end hydrogen and oxygen fuel cell stack 110. That is, the second gas passage 131, the second channel of the blind-end hydrogen and oxygen fuel cell stack 110, and the second discharge pipeline 133 are connected to form the oxygen path 103. The second on-off valve 132 is arranged in the second gas passage 131 to control the on-off of the second gas passage 131.

[0086] After the first gas passage 121 delivers hydrogen to the blind-end hydrogen-oxygen fuel cell stack 110 and the second gas passage 131 delivers oxygen to the blind-end hydrogen-oxygen fuel cell stack 110, the hydrogen and oxygen undergo an electrochemical reaction in the blind-end hydrogen-oxygen fuel cell stack 110. The blind-end hydrogen-oxygen fuel cell stack 110 discharges a mixture of hydrogen and liquid water through the first discharge pipeline 123 and discharges a mixture of oxygen and liquid water through the second discharge pipeline 133, so that the blind-end hydrogen-oxygen fuel cell stack 110 can discharge water and avoid damage to the blind-end hydrogen-oxygen fuel cell stack 110 caused by accumulation of liquid water.

[0087] Generally, the blind-end hydrogen-oxygen fuel cell stack 110 discharges liquid water produced by the electrochemical reaction through the first discharge pipeline 123 and the second discharge pipeline 133. Only when the average single-chip voltage or the lowest single-chip voltage of the blind-end hydrogen-oxygen fuel cell stack 110 is lower than a certain threshold value, the first discharge pipeline 123 and the second discharge pipeline 133 discharge hydrogen and oxygen respectively.

[0088] When the fuel cell system 100 is shut down, the first on-off valve 122 is controlled to shut off the first gas passage 121, and the second on-off valve 132 is controlled to shut off the second gas passage 131. At this time, the first gas passage 121 is no longer transporting hydrogen, the second gas passage 131 is no longer transporting oxygen, and the blind-end hydrogen-oxygen fuel cell stack 110 does not undergo an electrochemical reaction. However, there will be residual hydrogen and oxygen in the blind-end hydrogen-oxygen fuel cell stack 110, and the hydrogen and oxygen are pure hydrogen and pure oxygen. Pure hydrogen and pure oxygen (hereinafter only replaced by hydrogen and oxygen) react with the catalyst of the membrane electrode, resulting in a large open circuit voltage of pure hydrogen and pure oxygen in the blind-end hydrogen-oxygen fuel cell stack 110, which affects the service life of the membrane electrode.

[0089] To this end, the fuel cell system 100 of the present application is further provided with a purge structure 140, and the purge structure 140 connects the first gas passage 121 and the second gas passage 131. The purge of the present application is actually a shutdown purge, which is only replaced by purge in the following text. When the fuel cell system 100 is shut down, the purge structure 140 can work to output purge gas, and the purge gas can enter the blind-end hydrogen and oxygen fuel cell stack 110 to discharge hydrogen and oxygen from the blind-end hydrogen and oxygen fuel cell stack 110. That is, the hydrogen and oxygen in the blind-end hydrogen and oxygen fuel cell stack 110 are replaced by the purge gas.

[0090] After purging the blind-end hydrogen-oxygen fuel cell stack 110, only purge gas exists in the blind-end hydrogen-oxygen fuel cell stack 110. The purge gas will not react with the catalyst of the membrane electrode, thereby reducing the open circuit voltage of the blind-end fuel cell stack, ensuring the service life of the membrane electrode, and further ensuring the performance and life of the blind-end fuel cell stack.

[0091] Of course, the purge structure 140 is also connected to the first exhaust pipeline 123 and the second exhaust pipeline 133. After the purge gas is introduced into the blind-end hydrogen-oxygen fuel cell stack 110, the purge gas can gradually discharge hydrogen and oxygen. At this time, hydrogen can enter the purge structure 140 through the first exhaust pipeline 123 and then be discharged, and oxygen can enter the purge structure 140 through the second exhaust pipeline 133 and then be discharged.

[0092] At the same time, after the fuel cell system 100 is applied to the underwater equipment, the installation space where the fuel cell system 100 is located is a closed space, and the purge gas is pre-filled in the installation space. When the fuel cell system 100 is shut down, the purge structure 140 can use the purge gas in the installation space to purge the blind end hydrogen and oxygen fuel cell stack 110, without carrying a nitrogen bottle for purge gas supply, reducing the overall volume of the fuel cell system 100 and reducing the complexity of the structure of the fuel cell system 100.

[0093] When the fuel cell system 100 of the above embodiment is shut down, the purge structure 140 can pass the purge gas into the first gas passage 121 and the second gas passage 131, and then the purge gas can cause hydrogen to be discharged from the first gas passage 121, the blind-end hydrogen and oxygen fuel cell stack 110, the first exhaust pipeline 123 and the purge structure 140, and cause oxygen to be discharged from the second gas passage 131, the blind-end hydrogen and oxygen fuel cell stack 110, the second exhaust pipeline 133 and the purge structure 140.

[0094] In this way, there will be no residual hydrogen and oxygen in the blind-end hydrogen and oxygen fuel cell stack 110, thus avoiding irreversible damage to the membrane electrode such as carbon corrosion and platinum oxidation, thereby avoiding the blind-end hydrogen and oxygen fuel cell stack 110 from being in a high-voltage open circuit state for a long time, thereby ensuring the performance and life of the blind-end hydrogen and oxygen fuel cell stack 110. At the same time, the purge structure 140 uses the gas pre-stored in the installation space of the fuel cell system 100 as the purge gas, and there is no need to carry a nitrogen bottle specifically for providing the purge gas, thereby reducing the volume and structural complexity of the fuel cell system 100.

[0095] Referring to FIGS. 1 to 3 , in one embodiment, the hydrogen delivery structure 120 further includes a high-pressure hydrogen bottle 124, which is connected to the first gas passage 121. The high-pressure hydrogen bottle 124 is a bottle for storing high-pressure hydrogen. The high-pressure hydrogen bottle 124 can deliver hydrogen to the first channel (not mentioned later) of the blind-end hydrogen-oxygen fuel cell stack 110 through the first gas passage 121.

[0096] Referring to FIGS. 1 to 3 , in one embodiment, the oxygen delivery structure 130 further includes a high-pressure oxygen bottle 134, which is connected to the second gas passage 131. The high-pressure oxygen bottle 134 is a bottle body for storing high-pressure oxygen. The high-pressure oxygen bottle 134 can deliver oxygen to the second channel (not mentioned later) of the blind-end hydrogen-oxygen fuel cell stack 110 through the second gas passage 131.

[0097] In one embodiment, the first on-off valve 122 and the second on-off valve 132 are both solenoid valves. Of course, in other embodiments of the present application, the first on-off valve 122 and the second on-off valve 132 can also be other valves capable of realizing on-off control.

[0098] In one embodiment, the purge structure 140 uses air as the purge gas, and the purge pump 141 first purges the second gas passage 131 through the first purge assembly 142 and the second purge assembly 143, and then simultaneously purges the first gas passage 121 and the second gas passage 131. Alternatively, when the purge structure 140 uses nitrogen as the purge gas, the purge pump 141 simultaneously purges the first gas passage 121 and the second gas passage 131 through the first purge assembly 142 and the second purge assembly 143. The fuel cell system 100 of the present application can use air as the purge gas, and can also use nitrogen as the purge gas.

[0099] When air is used as the purge gas, the second gas passage 131 (hereinafter referred to as the oxygen passage 103) needs to be purged first. This is because air contains oxygen. If air is first passed into the first gas passage 121 (hereinafter referred to as the hydrogen passage 102) for purging, the oxygen in the air will react with the hydrogen in the hydrogen passage 102, and the blind end hydrogen-oxygen fuel cell stack 110 cannot be purged.

[0100] The purge structure 140 is disconnected from the hydrogen path 102, and air is first introduced into the oxygen path 103. The air flows under pressure in the oxygen path 103, which can consume the hydrogen in the blind end hydrogen-oxygen fuel cell stack 110, so that the hydrogen path 102 is in a state of slight negative pressure. Subsequently, the purge structure 140 delivers air to the hydrogen path 102 and the oxygen path 103 respectively to purge the hydrogen path 102 and the oxygen path 103. After the purge is completed, the purge structure 140 stops working.

[0101] When nitrogen is used as the purge gas, since nitrogen does not react with hydrogen and oxygen, the purge structure 140 can simultaneously deliver nitrogen to the hydrogen path 102 and the oxygen path 103. Specifically, the purge structure 140 delivers nitrogen to the hydrogen path 102 and the oxygen path 103 respectively to purge the hydrogen path 102 and the oxygen path 103. After the purge is completed, the purge structure 140 stops working.

[0102] In order to better illustrate the specific structure of the purge structure 140, here we only take the example of the purge structure 140 simultaneously transporting the purge gas through the hydrogen path 102 and the oxygen path 103 for explanation. As to whether the purge gas is air or nitrogen, this will be explained in detail when describing the purge process and purge method of the fuel cell system 100.

[0103] Referring to FIGS. 1 to 4 , in one embodiment, the purge structure 140 includes a purge pump 141, a first purge assembly 142, and a second purge assembly 143. The first purge assembly 142 connects the first gas passage 121 and the second gas passage 131, and is located between the first on-off valve 122 and the blind-end hydrogen-oxygen fuel cell stack 110. The second purge assembly 143 connects the first exhaust pipeline 123 and the second exhaust pipeline 133. The purge pump 141 is connected to the first purge assembly 142, and controls the first purge assembly 142 and the second purge assembly 143 to purge at least one of the first gas passage 121 and the second gas passage 131.

[0104] One end of the first purge assembly 142 is connected to the first gas passage 121 and is located between the first on-off valve 122 and the blind-end hydrogen-oxygen fuel cell stack 110. The other end of the first purge assembly 142 is connected to the second gas passage 131 and is located between the second on-off valve 132 and the blind-end hydrogen-oxygen fuel cell stack 110. The purge pump 141 is a power source for the purge structure 140, and the purge pump 141 is connected to the first purge assembly 142.

[0105] In this way, the purge pump 141 can deliver the purge gas to the hydrogen path 102 and the oxygen path 103 through the first purge assembly 142. One end of the second purge assembly 143 is connected to the first exhaust pipeline 123, and the other end of the second purge assembly 143 is connected to the second exhaust pipeline 133. In this way, the hydrogen or purge gas output from the first exhaust pipeline 123 can be discharged through the second purge assembly 143, and the oxygen or purge gas output from the second exhaust pipeline 133 can be discharged through the second purge assembly 143, so as to achieve the purge of the blind end hydrogen and oxygen fuel cell stack 110. Optionally, the purge pump 141 is a vacuum pump.

[0106] 1 to 4, in one embodiment, the first purge assembly 142 includes a first connecting pipeline 1421, a first control valve 1422, and a second control valve 1423. The first connecting pipeline 1421 connects the first gas passage 121 and the second gas passage 131. The first control valve 1422 and the second control valve 1423 are arranged at intervals in the first connecting pipeline 1421. The purge pump 141 is connected between the first control valve 1422 and the second control valve 1423. The second purge assembly 143 includes a second connecting pipeline 1431, a third control valve 1432, a fourth control valve 1433, and a third exhaust pipeline 1434. The second connecting pipeline 1431 connects the first exhaust pipeline 123 and the second exhaust pipeline 133. The third control valve 1432 and the fourth control valve 1433 are arranged at intervals in the second connecting pipeline 1431. The third exhaust pipeline 1434 is connected to the second connecting pipeline 1431.

[0107] One end of the first connecting pipeline 1421 is located between the first on-off valve 122 and the blind end hydrogen and oxygen fuel cell stack 110, and is connected to the first gas passage 121. The other end of the second connecting pipeline 1431 is located between the second on-off valve 132 and the blind end hydrogen and oxygen fuel cell stack 110, and is connected to the second gas passage 131. In this way, the first connecting pipeline 1421 can connect the first gas passage 121 and the second gas passage 131. The first control valve 1422 and the second control valve 1423 are arranged at intervals on the first connecting pipeline 1421, and the first control valve 1422 and the second control valve 1423 can control the on and off of the first connecting pipeline 1421.

[0108] Moreover, the purge pump 141 is connected between the first control valve 1422 and the second control valve 1423. When the first control valve 1422 is opened and the second control valve 1423 is closed, the purge pump 141 is connected to the first gas passage 121 through the first connecting pipe 1421; when the first control valve 1422 is closed and the second control valve 1423 is opened, the purge pump 141 is connected to the second gas passage 131 through the first connecting pipe 1421; when both the first control valve 1422 and the second control valve 1423 are opened, the purge pump 141 is connected to the first gas passage 121 and the second gas passage 131 at the same time through the first connecting pipe 1421. When both the first control valve 1422 and the second control valve 1423 are closed, the first connecting pipe 1421 is disconnected from the first gas passage 121 and the second gas passage 131.

[0109] One end of the second connecting pipeline 1431 is connected to the first discharge pipeline 123, and the other end of the second connecting pipeline 1431 is connected to the second discharge pipeline 133. In this way, the second connecting pipeline 1431 can connect the first discharge pipeline 123 and the second discharge pipeline 133. The third discharge pipeline 1434 is connected to the second connecting pipeline 1431. The hydrogen or purge gas output by the first discharge pipeline 123 can be discharged through the second connecting pipeline 1431 and the third discharge pipeline 1434, and the oxygen or purge gas output by the second discharge pipeline 133 can be discharged through the second connecting pipeline 1431 and the third discharge pipeline 1434. The third control valve 1432 and the fourth control valve 1433 are arranged at intervals on the second connecting pipeline 1431, and the third control valve 1432 and the fourth control valve 1433 can control the on-off of the second connecting pipeline 1431.

[0110] Moreover, the third discharge pipeline 1434 is connected between the third control valve 1432 and the fourth control valve 1433. When the third control valve 1432 is opened and the fourth control valve 1433 is closed, the first discharge pipeline 123 is connected to the third discharge pipeline 1434 through the second connecting pipeline 1431; when the third control valve 1432 is closed and the fourth control valve 1433 is opened, the second discharge pipeline 133 is connected to the third discharge pipeline 1434 through the second connecting pipeline 1431; when the third control valve 1432 and the fourth control valve 1433 are both opened, the first discharge pipeline 123 and the second discharge pipeline 133 are simultaneously connected to the third discharge pipeline 1434 through the second connecting pipeline 1431; when the third control valve 1432 and the fourth control valve 1433 are both closed, the second connecting pipeline 1431 is disconnected from the first discharge pipeline 123 and the second discharge pipeline 133.

[0111] When the purge structure 140 uses air as the purge gas, the first control valve 1422 and the third control valve 1432 are first controlled to be closed, and the second control valve 1423 and the fourth control valve 1433 are opened. At this time, the hydrogen path 102 is disconnected and the oxygen path 103 is open. Subsequently, the first control valve 1422 and the third control valve 1432 are controlled to be opened, and the hydrogen path 102 and the oxygen path 103 are both open. After the purge is completed, the first control valve 1422, the second control valve 1423, the third control valve 1432 and the fourth control valve 1433 are all closed.

[0112] When the purge structure 140 uses nitrogen as the purge gas, the first control valve 1422, the second control valve 1423, the third control valve 1432 and the fourth control valve 1433 are all opened, and the hydrogen path 102 and the oxygen path 103 are both passages. After the purge is completed, the first control valve 1422, the second control valve 1423, the third control valve 1432 and the fourth control valve 1433 are all closed.

[0113] In one embodiment, the first control valve 1422, the second control valve 1423, the third control valve 1432, and the fourth control valve 1433 are all solenoid valves. Of course, in other embodiments of the present application, the first control valve 1422, the second control valve 1423, the third control valve 1432, and the fourth control valve 1433 can also be other valves that can control the on-off of the pipeline.

[0114] Referring to Figures 1 to 4, in one embodiment, the first purge assembly 142 also includes a first regulating valve 1424 and a second regulating valve 1425. The first regulating valve 1424 is arranged in the first gas passage 121 and is located between the first purge assembly 142 and the blind-end hydrogen-oxygen fuel cell stack 110. The second regulating valve 1425 is arranged in the second gas passage 131 and is located between the first purge assembly 142 and the blind-end hydrogen-oxygen fuel cell stack 110.

[0115] The first regulating valve 1424 is provided in the first gas passage 121. By adjusting the duty ratio (opening degree) of the first regulating valve 1424, the flow rate of the purge gas in the first gas passage 121 can be adjusted. The second regulating valve 1425 is provided in the second gas passage 131. By adjusting the duty ratio of the second regulating valve 1425, the flow rate of the purge gas in the second gas passage 131 can be adjusted.

[0116] In this way, by regulating the rotation speed of the purge pump 141 and the duty ratio of the first regulating valve 1424 and the second regulating valve 1425, the pressure of the purge gas in the first gas passage 121 and the second gas passage 131 can be adjusted, so that the purge gas can be delivered to the blind-end hydrogen-oxygen fuel cell stack 110 at a certain target pressure. Of course, the hydrogen delivery structure 120 may include the first regulating valve 1424, and the oxygen delivery structure 130 may include the second regulating valve 1425.

[0117] In one embodiment, the first regulating valve 1424 and the second regulating valve 1425 are both proportional valves, and the duty cycle of the proportional valves is regulated, that is, the opening of the proportional valves is regulated to adjust the flow rates of the first gas passage 121 and the second gas passage 131. Of course, in other embodiments of the present application, the first regulating valve 1424 and the second regulating valve 1425 can also be other valves capable of adjusting the opening.

[0118] 1 to 4 , in one embodiment, the hydrogen delivery structure 120 further includes two first temperature and pressure detection members 125, which are respectively disposed in the first gas passage 121 and the first exhaust pipeline 123, and are disposed close to the blind end hydrogen and oxygen fuel cell stack 110. The oxygen delivery structure 130 further includes two second temperature and pressure detection members 135, which are respectively disposed in the second gas passage 131 and the second exhaust pipeline 133, and are disposed close to the blind end hydrogen and oxygen fuel cell stack 110.

[0119] One of the first temperature and pressure detection components 125 is disposed at one end of the first gas passage 121 close to the blind end hydrogen and oxygen fuel cell stack 110, and the first temperature and pressure detection component 125 can detect the temperature and pressure of the hydrogen inlet end. Another first temperature and pressure detection component 125 is disposed at one end of the first exhaust pipeline 123 close to the blind end hydrogen and oxygen fuel cell stack 110, and the first temperature and pressure detection component 125 can detect the temperature and pressure of the hydrogen outlet end.

[0120] One of the second temperature and pressure detection components 135 is disposed at one end of the second gas passage 131 close to the blind end hydrogen and oxygen fuel cell stack 110, and the second temperature and pressure detection component 135 can detect the temperature and pressure of the oxygen inlet end. Another second temperature and pressure detection component 135 is disposed at one end of the second exhaust pipeline 133 close to the blind end hydrogen and oxygen fuel cell stack 110, and the second temperature and pressure detection component 135 can detect the temperature and pressure of the oxygen outlet end.

[0121] The pressure value in the hydrogen path 102 can be detected by the first temperature and pressure detection components 125 at both ends of the blind-end hydrogen and oxygen fuel cell stack 110, and the pressure value in the oxygen path 103 can be detected by the second temperature and pressure detection components 135 at both ends of the blind-end hydrogen and oxygen fuel cell stack 110. In this way, when the purge structure 140 purges the blind-end hydrogen and oxygen fuel cell stack 110, the purge mode can be adjusted according to the pressure values ​​of the hydrogen path 102 and the oxygen path 103.

[0122] 1 to 3 , in one embodiment, the hydrogen delivery structure 120 further includes a first pressure detection member 126, which is disposed in the first gas passage 121 and located between the first on-off valve 122 and the first purge assembly 142. The oxygen delivery structure 130 further includes a second pressure detection member 136, which is disposed in the second gas passage 131 and located between the second on-off valve 132 and the first purge assembly 142.

[0123] The first pressure detection member 126 can detect the pressure value of the first gas passage 121, and the second pressure detection member 136 can detect the pressure value of the second gas passage 131. In this way, the pressure value in the hydrogen path 102 can be detected by the cooperation of the first pressure detection member 126, and the pressure value in the oxygen path 103 can be detected by the cooperation of the second pressure detection member 136. In this way, when the purge structure 140 purges the blind-end hydrogen-oxygen fuel cell stack 110, the purge mode can be adjusted according to the pressure values ​​of the hydrogen path 102 and the oxygen path 103.

[0124] In this embodiment, the pressure value in the hydrogen path 102 can be detected by the cooperation of the first temperature and pressure detection member 125 and the first pressure detection member 126, and the pressure value in the oxygen path 103 can be detected by the cooperation of the second temperature and pressure detection member 135 and the second pressure detection member 136. In this way, when the purge structure 140 purges the blind-end hydrogen-oxygen fuel cell stack 110, the purge mode can be adjusted according to the pressure values ​​of the hydrogen path 102 and the oxygen path 103.

[0125] In one embodiment, the first temperature and pressure detection member 125 and the second temperature and pressure detection member 135 are temperature and pressure sensors. Of course, in other embodiments of the present application, the first temperature and pressure detection member 125 and the second temperature and pressure detection member 135 can also be a temperature gauge and a pressure gauge. In one embodiment, the first pressure detection member 126 and the second pressure detection member 136 are pressure sensors. Of course, in other embodiments of the present application, the first pressure detection member 126 and the second pressure detection member 136 can also be a pressure gauge.

[0126] Referring to Figures 1 and 4, in one embodiment, the hydrogen delivery structure 120 also includes a first separator 127 and a first drain valve 128. The first drain valve 128 is arranged in the first discharge pipeline 123 and is located on the side of the second purge assembly 143 away from the blind end hydrogen and oxygen fuel cell stack 110. The first separator 127 is arranged in the first discharge pipeline 123 and is located between the second purge assembly 143 and the first drain valve 128.

[0127] The first separator 127 can separate hydrogen from liquid water. The first drain valve 128 can control the on-off of the first discharge pipeline 123. The liquid water produced by the electrochemical reaction of the blind-end hydrogen-oxygen fuel cell stack 110 contains hydrogen. After the liquid water is discharged, it passes through the first discharge pipeline 123 and enters the first separator 127 for water vapor separation. The liquid water is discharged into a drainage container (not shown) through the drain valve.

[0128] Referring to Figures 1 and 4, in one embodiment, the oxygen delivery structure 130 also includes a second separator 137 and a second drain valve 138. The second drain valve 138 is arranged in the second discharge pipeline 133 and is located on the side of the second purge assembly 143 away from the blind end hydrogen and oxygen fuel cell stack 110. The second separator 137 is arranged in the second discharge pipeline 133 and is located between the second purge assembly 143 and the second drain valve 138.

[0129] The second separator 137 can separate oxygen from liquid water. The second drain valve 138 can control the on-off of the second discharge pipeline 133. The liquid water produced by the electrochemical reaction of the blind-end hydrogen-oxygen fuel cell stack 110 contains oxygen. After the liquid water is discharged, it passes through the second drain pipeline and enters the second separator 137 for water vapor separation. The liquid water is discharged into the drainage container through the second drain valve 138.

[0130] Optionally, the drainage container is a water tank, etc. Optionally, the hydrogen delivery structure 120 and the oxygen delivery structure 130 correspond to a drainage container respectively. Optionally, the first drainage valve 128 and the second drainage valve 138 are solenoid valves, etc.

[0131] 1 , in one embodiment, the fuel cell system 100 further includes a hydrogen removal structure 150, which is connected to the third exhaust pipe 1434 of the second purge assembly 143. It can be understood that when the average single-chip voltage of the blind-end hydrogen-oxygen fuel cell stack 110 is too low or the minimum single-chip voltage is low, it is still necessary to discharge a portion of the accumulated impurity gas to improve performance.

[0132] To this end, a hydrogen elimination structure 150 is provided at the output end of the third exhaust pipeline 1434 for processing the discharged hydrogen and oxygen. In this way, the hydrogen discharged from the hydrogen-oxygen fuel cell stack 110 at the purging blind end can enter the hydrogen elimination structure 150 for elimination. It is worth noting that the hydrogen elimination structure 150 can adopt an existing solution for achieving hydrogen elimination, and its specific structure is not repeated here.

[0133] Referring to Figures 1 and 5, Figure 5 is a schematic diagram of the flow of the purge gas in the fuel cell system 100 shown in Figure 1, wherein the direction of the dashed arrow is the flow direction of the purge gas. After the fuel cell system 100 of the present application receives a shutdown command, the hydrogen delivery structure 120 (hydrogen path 102) and the oxygen delivery structure 130 (oxygen path 103) slowly return to normal pressure, such as 101 kPa (absolute pressure, ABS).

[0134] Subsequently, the hydrogen path 102 is controlled to stop conveying hydrogen, the oxygen path 103 is controlled to stop conveying oxygen, and the first on-off valve 122, the first regulating valve 1424, the first drain valve 128, the second on-off valve 132, the second regulating valve 1425, and the second drain valve 138 are closed. At this time, hydrogen still remains in the hydrogen path 102, and residual oxygen remains in the oxygen path 103. The purge structure 140 is required to purge the hydrogen path 102 and the oxygen path 103 to replace the hydrogen in the hydrogen path 102 and the oxygen in the oxygen path 103 with purge gas.

[0135] When the purge gas is air, the first control valve 1422 and the third control valve 1432 are closed, and the second control valve 1423 and the fourth control valve 1433 are opened. At this time, the oxygen path 103 is a passage. The purge pump 141 is turned on, and the speed of the purge pump 141 and the duty cycle of the second regulating valve 1425 are adjusted. The purge pump 141 purges the oxygen path 103: the purge pump 141 discharges the air through the first connecting pipeline 1421, the second control valve 1423, the second gas passage 131, the blind end hydrogen and oxygen fuel cell stack 110, the second exhaust pipeline 133, the fourth control valve 1433, the second connecting pipeline 1431 and the third exhaust pipeline 1434, so as to replace the oxygen in the oxygen path 103 with air.

[0136] During the process of the purge pump 141 purging the oxygen path 103, since the hydrogen path 102 is at normal pressure, the purge pump 141 pressurizes the oxygen path 103, which can consume part of the hydrogen in the hydrogen path 102, so that the hydrogen path 102 is in a state of slight negative pressure. When the pressure of the hydrogen path 102 is not higher than the first set threshold value P1, the first control valve 1422 and the third control valve 1432 are controlled to open, and the duty cycle of the second regulating valve 1425 is adjusted to control the pressure of the hydrogen path 102 and the oxygen path 103 to be substantially equal and not higher than the second set threshold value P2, so that the air in the hydrogen path 102 and the oxygen path 103 can be purged into the hydrogen elimination structure 150.

[0137] When the purge gas is nitrogen, the first control valve 1422, the second control valve 1423, the third control valve 1432 and the fourth control valve 1433 are controlled to be open, and at this time, the hydrogen path 102 and the oxygen path 103 are both passages. The purge pump 141 is started, and the speed of the purge pump 141 and the duty ratio of the first regulating valve 1424 and the second regulating valve 1425 are regulated to control the pressure of the hydrogen path 102 and the oxygen path 103 to be substantially equal and not higher than the second set threshold value P2, so that the nitrogen in the hydrogen path 102 and the oxygen path 103 can be purged into the hydrogen elimination structure 150.

[0138] After the purge gas in the hydrogen path 102 and the oxygen path 103 is purged to the hydrogen elimination structure 150, the speed of the circulatory adjustment purge pump 141 is adjusted, and the pressure of the hydrogen path 102 and the oxygen path 103 is disturbed by changing the speed to quickly purge the hydrogen and oxygen in the blind end hydrogen and oxygen fuel cell stack 110. When the single chip voltage of the blind end hydrogen and oxygen fuel cell stack 110 is within a preset range, the first control valve 1422, the second control valve 1423, the third control valve 1432 and the fourth control valve 1433 are controlled to be closed, and the purge of the blind end hydrogen and oxygen fuel cell stack 110 is completed.

[0139] The fuel cell system 100 of the present application can realize the rapid purge of the underwater blind-end hydrogen-oxygen fuel cell stack 110 when it is shut down, avoid the blind-end hydrogen-oxygen fuel cell stack 110 being in a high-voltage open-circuit state for a long time, reduce the open-circuit voltage of the blind-end hydrogen-oxygen fuel cell stack 110, and ensure the performance and life of the blind-end hydrogen-oxygen fuel cell stack 110. In addition, the purge structure 140 uses a purge pump 141 and a corresponding valve as the main power consumption components, and only works when the blind-end hydrogen-oxygen fuel cell stack 110 is purged, thereby reducing the energy consumption of the fuel cell system 100.

[0140] At the same time, the fuel cell system 100 does not need to carry a nitrogen bottle, and uses the purge gas pre-stored in the installation space of the underwater equipment to purge the blind end hydrogen and oxygen fuel cell stack 110. Different modes of purge can be performed according to different types of purge gases, saving space in the underwater equipment for carrying more fuel and catalyst, and improving the cruising range of the underwater equipment.

[0141] The present application discloses a purging method for a fuel cell system 100, see Figures 5 and 6, Figure 6 is a purging flow chart of the fuel cell system 100 shown in Figure 5. The purging method for the fuel cell system 100 is applied to the fuel cell system 100 in any of the above embodiments, and the purging method includes at least the following steps:

[0142] Obtaining a shutdown instruction of the fuel cell system 100;

[0143] Control the hydrogen delivery structure 120 and the oxygen delivery structure 130 to close, and stop delivering hydrogen and oxygen;

[0144] Determining whether the purge gas in the installation space where the fuel cell system 100 is located is air;

[0145] If yes, the purge structure 140 is controlled to first purge the oxygen delivery structure 130, and then purge the hydrogen delivery structure 120 and the oxygen delivery structure 130 at the same time;

[0146] If not, the purge structure 140 is controlled to purge the hydrogen delivery structure 120 and the oxygen delivery structure 130 simultaneously;

[0147] Circularly purge the hydrogen delivery structure 120 and the oxygen delivery structure 130;

[0148] Obtaining a single-chip voltage of the blind-end hydrogen-oxygen fuel cell stack 110, and determining whether the single-chip voltage is within a preset range;

[0149] If so, the purge structure is controlled to stop purge;

[0150] If not, the hydrogen delivery structure 120 and the oxygen delivery structure 130 continue to be purged cyclically.

[0151] After the fuel cell system 100 receives the shutdown command, the hydrogen delivery structure 120 (hydrogen path 102) and the oxygen delivery structure 130 (oxygen path 103) slowly return to normal pressure, such as 101 kPa (absolute pressure, ABS). Subsequently, the hydrogen delivery structure 120 and the oxygen delivery structure 130 are closed, the hydrogen path 102 stops delivering hydrogen, and the oxygen path 103 stops delivering oxygen, that is, the first on-off valve 122, the first regulating valve 1424, the first drain valve 128, the second on-off valve 132, the second regulating valve 1425, and the second drain valve 138 are closed.

[0152] At this time, there is still residual hydrogen in the hydrogen path 102, and residual oxygen in the oxygen path 103, and the purge structure 140 is required to purge the hydrogen path 102 and the oxygen path 103 to replace the hydrogen in the hydrogen path 102 and the oxygen in the oxygen path 103 with purge gas. The purge gas is pre-stored in the installation space where the fuel cell system 100 is located, and the purge gas can be air or nitrogen. It is determined whether the purge gas is air.

[0153] If the purge gas is air, the purge structure 140 needs to purge the second gas passage 131 (oxygen passage 103) first. The purge structure 140 is disconnected from the first gas passage 121 (hydrogen passage 102), and air is first introduced into the oxygen passage 103. The air flows under pressure in the oxygen passage 103, which can consume the hydrogen in the blind-end hydrogen-oxygen fuel cell stack 110, so that the hydrogen passage 102 is in a state of slight negative pressure. Subsequently, the purge structure 140 delivers air to the hydrogen passage 102 and the oxygen passage 103 respectively to purge the hydrogen passage 102 and the oxygen passage 103. If the purge gas is not air but nitrogen, the purge structure 140 can deliver nitrogen to the hydrogen passage 102 and the oxygen passage 103 at the same time to purge the hydrogen passage 102 and the oxygen passage 103.

[0154] Subsequently, the hydrogen path 102 and the oxygen path 103 are circulated and purged. During the circulatory purge process, the average single-chip voltage of the blind-end hydrogen-oxygen fuel cell stack 110 is obtained. A preset range of single-chip voltages is pre-stored in the fuel system to determine whether the single-chip voltage of the blind-end hydrogen-oxygen fuel cell stack 110 is within the preset range. If the single-chip voltage is within the preset range, it indicates that the hydrogen and oxygen in the blind-end hydrogen-oxygen fuel cell stack 110 have replaced the purge gas.

[0155] If the single-chip voltage is outside the preset range, it indicates that the hydrogen and oxygen in the blind-end hydrogen-oxygen fuel cell stack 110 are not completely replaced, and it needs to be purged again. This process is repeated continuously until the single-chip voltage is within the preset range, and the purge structure 140 is controlled to shut down, that is, the first control valve 1422, the second control valve 1423, the third control valve 1432, and the fourth control valve 1433 are controlled to close, and the purge of the blind-end hydrogen-oxygen fuel cell stack 110 is completed.

[0156] In this embodiment, the single chip voltage is the average single chip voltage and the maximum single chip voltage. The preset range of the average single chip voltage and the maximum single chip voltage is pre-stored in the fuel system to determine whether the average single chip voltage and the maximum single chip voltage of the blind end hydrogen and oxygen fuel cell stack 110 are within the preset range.

[0157] If the average single-chip voltage and the highest single-chip voltage are within the preset range, it indicates that the hydrogen and oxygen in the blind-end hydrogen-oxygen fuel cell stack 110 have replaced the purge gas. If the average single-chip voltage and the highest single-chip voltage are outside the preset range, it indicates that the hydrogen and oxygen in the blind-end hydrogen-oxygen fuel cell stack 110 have not been completely replaced and need to be purged again.

[0158] In this embodiment, the voltage value of the average single-chip voltage is lower than 50mV, and the voltage value of the maximum single-chip voltage is no higher than 80mV. Of course, in other embodiments of the present application, the average single-chip voltage and the maximum single-chip voltage can also be other preset ranges, as long as the open circuit voltage of the blind-end hydrogen-oxygen fuel cell stack 110 can be reduced.

[0159] In other embodiments of the present application, the average single-chip voltage or the highest single-chip voltage may also be used to determine whether the hydrogen and oxygen in the blind-end hydrogen-oxygen fuel cell stack 110 are completely replaced.

[0160] 5 and 6 , in one embodiment, controlling the purge structure 140 to first purge the oxygen delivery structure 130 and then simultaneously purge the hydrogen delivery structure 120 and the oxygen delivery structure 130 includes the following steps:

[0161] Close the first control valve 1422 and the third control valve 1432, and open the second control valve 1423 and the fourth control valve 1433;

[0162] Turning on the purge pump 141, adjusting the rotation speed of the purge pump 141 and the duty cycle of the second regulating valve 1425, to purge the oxygen delivery structure 130;

[0163] Obtaining a first pressure of gas in the hydrogen delivery structure 120, and determining whether the first pressure is less than or equal to a first set threshold;

[0164] If yes, open the first control valve 1422 and the third control valve 1432;

[0165] If not, continue to regulate the rotation speed of the purge pump 141 and the duty cycle of the second regulating valve 1425 to purge the oxygen delivery structure 130 .

[0166] When the purge gas is air, the first control valve 1422 and the third control valve 1432 are closed, and the second control valve 1423 and the fourth control valve 1433 are opened. At this time, the oxygen path 103 is a passage. The purge pump 141 is turned on, and the speed of the purge pump 141 and the duty cycle of the second regulating valve 1425 are adjusted. The purge pump 141 purges the oxygen path 103: the purge pump 141 discharges the air through the first connecting pipeline 1421, the second control valve 1423, the second gas passage 131, the blind end hydrogen and oxygen fuel cell stack 110, the second exhaust pipeline 133, the fourth control valve 1433, the second connecting pipeline 1431 and the third exhaust pipeline 1434, so as to replace the oxygen in the oxygen path 103 with air.

[0167] During the process of the purge pump 141 purging the oxygen circuit 103, since the hydrogen circuit 102 is at normal pressure, the pressure difference between the oxygen circuit 103 and the hydrogen circuit 102 is the preset threshold value △P. The purge pump 141 pressurizes the oxygen circuit 103, which can consume part of the hydrogen in the hydrogen circuit 102, so that the hydrogen circuit 102 is in a state of slight negative pressure. When the pressure of the hydrogen circuit 102 is not higher than the first set threshold value P1, the first control valve 1422 and the third control valve 1432 are controlled to open, and the duty cycle of the second regulating valve 1425 is adjusted to control the pressure of the hydrogen circuit 102 and the oxygen circuit 103 to be basically equal and not higher than the second set threshold value P2, so that the air in the hydrogen circuit 102 and the oxygen circuit 103 can be purged into the hydrogen elimination structure 150.

[0168] In this embodiment, the preset threshold ΔP is 30 kPa (ABS), the first set threshold P1 is 30 kPa (ABS), and the second set threshold P2 is 130 kPa (ABS). Of course, in other embodiments of the present application, the preset threshold ΔP, the first set threshold P1, and the second set threshold P2 can also be other values, as long as the blind end hydrogen and oxygen fuel cell stack 110 can be purged.

[0169] 5 and 6 , in one embodiment, controlling the purge structure 140 to purge the hydrogen delivery structure 120 and the oxygen delivery structure 130 simultaneously includes the following steps:

[0170] Open the first control valve 1422, the third control valve 1432, the second control valve 1423, and the fourth control valve 1433;

[0171] The purge pump 141 is turned on, and the rotation speed of the purge pump 141 is adjusted.

[0172] When the purge gas is nitrogen, the first control valve 1422, the second control valve 1423, the third control valve 1432 and the fourth control valve 1433 are controlled to be open, and at this time, the hydrogen path 102 and the oxygen path 103 are both passages. The purge pump 141 is started, and the speed of the purge pump 141 and the duty ratio of the first regulating valve 1424 and the second regulating valve 1425 are regulated to control the pressure of the hydrogen path 102 and the oxygen path 103 to be substantially equal and not higher than the second set threshold value P2, so that the nitrogen in the hydrogen path 102 and the oxygen path 103 can be purged into the hydrogen elimination structure 150.

[0173] Subsequently, the hydrogen gas line 102 and the oxygen gas line 103 are circulated and purged.

[0174] 5 and 6 , in one embodiment, cyclically purging the hydrogen delivery structure 120 and the oxygen delivery structure 130 includes the following steps:

[0175] Regulating the duty ratio of the first regulating valve 1424 and the second regulating valve 1425;

[0176] Controlling the pressure in the oxygen delivery structure 130 and the pressure in the hydrogen delivery structure 120 to be equal and less than a second set threshold;

[0177] Control the purge pump 141 to purge at a first speed for a first preset time, purge at a second speed for a second preset time, and then purge at the first speed for the first preset time, and purge in sequence in a cycle;

[0178] The first rotation speed is different from the second rotation speed.

[0179] After the purge gas of the hydrogen path 102 and the oxygen path 103 is blown to the hydrogen elimination structure 150, the pressure in the oxygen delivery structure 130 and the hydrogen delivery structure 120 is equal and less than the second set threshold value. At this time, the hydrogen path 102 and the oxygen path 103 are pressure disturbed to discharge the residual hydrogen and oxygen in the blind-end hydrogen and oxygen fuel cell stack 110, thereby achieving rapid purge of hydrogen and oxygen in the blind-end hydrogen and oxygen fuel cell stack 110.

[0180] Specifically, the purge pump 141 first purges the hydrogen path 102 and the oxygen path 103 at a first speed for a first preset time, then purges the hydrogen path 102 and the oxygen path 103 at a second speed for a second preset time, and then purges the hydrogen path 102 and the oxygen path 103 at the first speed for a first preset time, and then circulates the purges in sequence. The pressure of the hydrogen path 102 and the oxygen path 103 is disturbed by changing the speed. Optionally, the first preset time and the second preset time are both 5s or other times.

[0181] During the cyclic purge process, the single-chip voltage of the blind-end hydrogen and oxygen fuel cell stack 110 is obtained. The preset range of the single-chip voltage is pre-stored in the fuel system to determine whether the single-chip voltage of the blind-end hydrogen and oxygen fuel cell stack 110 is within the preset range. When the single-chip voltage of the blind-end hydrogen and oxygen fuel cell stack 110 is within the preset range, the first control valve 1422, the second control valve 1423, the third control valve 1432 and the fourth control valve 1433 are controlled to close, and the purge of the blind-end hydrogen and oxygen fuel cell stack 110 is completed. If the single-chip voltage is outside the preset range, it indicates that the hydrogen and oxygen in the blind-end hydrogen and oxygen fuel cell stack 110 are not completely replaced, and it needs to be purged again.

[0182] The purging method of the fuel cell system 100 of the present application can realize that the underwater equipment with the fuel cell system 100 does not need to carry inert purge gas cylinders such as nitrogen, thereby saving space of the fuel cell system 100 for carrying more fuel and catalyst, thereby improving the cruising range of the underwater equipment.

[0183] Moreover, it is also possible to achieve rapid purging of the blind-end hydrogen and oxygen fuel cell stack 110 after receiving a shutdown command, so that the average single-chip voltage and the maximum single-chip voltage of the blind-end hydrogen and oxygen fuel cell stack 110 can be reduced to a reasonable threshold in a short period of time, thereby protecting the performance of the blind-end hydrogen and oxygen fuel cell stack 110 and extending its service life.

[0184] At the same time, the cooperation of the hydrogen removal equipment inside the underwater equipment can avoid the concentration of hydrogen in the underwater equipment being too high, and make the concentration of hydrogen in the underwater equipment far below the lower limit of the hydrogen explosion value, thereby ensuring the safety of the underwater equipment operation.

[0185] The present application also provides an underwater device, including an underwater host and a fuel cell system 100 as in any of the above embodiments. The fuel cell system 100 is arranged on the underwater host and supplies power to the underwater host. After the underwater device of the present application adopts the fuel cell system 100 of the above embodiment, it can ensure the performance and life of the blind-end hydrogen-oxygen fuel cell stack 110 while supplying power to the underwater host, save space in the underwater device, so as to carry more fuel and catalyst, and improve the cruising range of the underwater device.

[0186] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0187] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A fuel cell system, characterized in that: include: Blind-end hydrogen and oxygen fuel cell stack; A hydrogen delivery structure, comprising a first gas passage, a first on-off valve and a first exhaust pipeline, wherein the first gas passage and the first exhaust pipeline are respectively arranged at two ends of the blind-end hydrogen-oxygen fuel cell stack, and the first on-off valve is arranged in the first gas passage; an oxygen delivery structure, comprising a second gas passage, a second on-off valve and a second exhaust pipeline, wherein the second gas passage and the second exhaust pipeline are respectively arranged at two ends of the blind-end hydrogen-oxygen fuel cell stack, and the second on-off valve is arranged in the second gas passage; The purge structure is connected to at least the first gas passage and the second gas passage. When the fuel cell system is shut down, the purge structure can supply purge gas to the first gas passage and the second gas passage. The purge gas is pre-stored in the installation space of the fuel cell system.

2. The fuel cell system according to claim 1, characterized in that: The purge structure includes a purge pump, a first purge component and a second purge component; The first purge assembly is connected to the first gas passage and the second gas passage, and is located between the first on-off valve and the blind-end hydrogen-oxygen fuel cell stack; The second purge assembly is connected to the first exhaust pipeline and the second exhaust pipeline; The purge pump is connected to the first purge assembly and controls the first purge assembly and the second purge assembly to purge at least one of the first gas passage and the second gas passage.

3. The fuel cell system according to claim 2, characterized in that: The first purge assembly includes a first connecting pipeline, a first control valve and a second control valve, the first connecting pipeline connects the first gas passage and the second gas passage, the first control valve and the second control valve are arranged in the first connecting pipeline at intervals, and the purge pump is connected between the first control valve and the second control valve; The second purge assembly includes a second connecting pipeline, a third control valve, a fourth control valve and a third exhaust pipeline. The second connecting pipeline connects the first exhaust pipeline and the second exhaust pipeline. The third control valve and the fourth control valve are spaced apart in the second connecting pipeline. The third exhaust pipeline is connected to the second connecting pipeline.

4. The fuel cell system according to claim 2 or 3, characterized in that: The fuel cell system comprises at least one of the following features: In the first item, the purge structure uses air as the purge gas, and the purge pump first purges the second gas passage through the first purge component and the second purge component, and then purges the first gas passage and the second gas passage at the same time; Alternatively, the purge structure uses nitrogen as the purge gas, and the purge pump simultaneously purges the first gas passage and the second gas passage through the first purge component and the second purge component; Second, the hydrogen delivery structure further includes two first temperature and pressure detection components, which are respectively disposed in the first gas passage and the first exhaust pipeline, and are disposed close to the blind-end hydrogen-oxygen fuel cell stack; The oxygen delivery structure further includes two second temperature and pressure detection components, which are respectively arranged in the second gas passage and the second exhaust pipeline, and are arranged close to the blind-end hydrogen and oxygen fuel cell stack; Item 3, the hydrogen delivery structure further comprises a first pressure detection member, the first pressure detection member is arranged in the first gas passage and is located between the first on-off valve and the first purge assembly; The oxygen delivery structure further includes a second pressure detection member, which is disposed in the second gas passage and located between the second on-off valve and the first purge assembly; Fourthly, the hydrogen delivery structure further comprises a first separator and a first drain valve, wherein the first drain valve is arranged in the first discharge pipeline and is located on a side of the second purge assembly away from the blind end hydrogen-oxygen fuel cell stack, and the first separator is arranged in the first discharge pipeline and is located between the second purge assembly and the first drain valve; The oxygen delivery structure further includes a second separator and a second drain valve, wherein the second drain valve is disposed in the second discharge pipeline and is located on a side of the second purge assembly away from the blind-end hydrogen-oxygen fuel cell stack, and the second separator is disposed in the second discharge pipeline and is located between the second purge assembly and the second drain valve; Item 5, the fuel cell system further includes a hydrogen removal structure, and the hydrogen removal structure is connected to the third exhaust pipeline of the second purge assembly.

5. The fuel cell system according to claim 2 or 3, characterized in that: The first purge assembly further includes a first regulating valve and a second regulating valve, wherein the first regulating valve is disposed in the first gas passage and is located between the first purge assembly and the blind-end hydrogen-oxygen fuel cell stack; The second regulating valve is arranged in the second gas passage and is located between the first purge assembly and the blind-end hydrogen-oxygen fuel cell stack.

6. A purging method for a fuel cell system, characterized in that: Applied to the fuel cell system according to any one of claims 1 to 5, the purge method comprises at least the following steps: Obtaining a shutdown instruction of the fuel cell system; Control the hydrogen delivery structure and the oxygen delivery structure to close, and stop delivering hydrogen and oxygen; Determining whether the purge gas in the installation space where the fuel cell system is located is air; If yes, control the purge structure to first purge the oxygen delivery structure, and then purge the hydrogen delivery structure and the oxygen delivery structure at the same time; If not, controlling the purge structure to purge the hydrogen delivery structure and the oxygen delivery structure simultaneously; Circularly purging the hydrogen delivery structure and the oxygen delivery structure; Obtaining a single-chip voltage of a blind-end hydrogen-oxygen fuel cell stack, and determining whether the single-chip voltage is within a preset range; If so, controlling the purge structure to stop purge; If not, continue to circulate and purge the hydrogen delivery structure and the oxygen delivery structure; The single chip voltage is an average single chip voltage and / or a maximum single chip voltage.

7. The purging method according to claim 6, characterized in that: Controlling the purge structure to first purge the oxygen delivery structure, and then simultaneously purge the hydrogen delivery structure and the oxygen delivery structure, comprises the following steps: Close the first control valve and the third control valve, and open the second control valve and the fourth control valve; Turning on the purge pump, adjusting the rotation speed of the purge pump and the duty cycle of the second regulating valve to purge the oxygen delivery structure; Obtaining a first pressure of gas in the hydrogen delivery structure, and determining whether the first pressure is less than or equal to a first set threshold; If yes, open the first control valve and the third control valve; If not, continue to regulate the rotation speed of the purge pump and the duty cycle of the second regulating valve to purge the oxygen delivery structure.

8. The purging method according to claim 6, characterized in that: Controlling the purge structure to purge the hydrogen delivery structure and the oxygen delivery structure simultaneously comprises the following steps: Open the first control valve, the third control valve, the second control valve, and the fourth control valve; The purge pump is turned on, and the rotation speed of the purge pump is adjusted.

9. The purging method according to any one of claims 6 to 8, characterized in that: The hydrogen delivery structure and the oxygen delivery structure are cyclically purged, comprising the following steps: Regulating the duty ratio of the first regulating valve and the second regulating valve; Controlling the pressure in the oxygen delivery structure and the pressure in the hydrogen delivery structure to be equal and less than a second set threshold; Control the purge pump to purge at a first speed for a first preset time, purge at a second speed for a second preset time, and then purge at the first speed for the first preset time, and purge in sequence in a cycle; The first rotational speed is different from the second rotational speed.

10. An underwater device, characterized in that: It comprises an underwater host and a fuel cell system as claimed in any one of claims 1 to 5; The fuel cell system is arranged on the underwater host and provides power for the underwater host.

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