Fuel cell system

Abstract

The present disclosure proposes a fuel cell system including: an electrical stack; an anode gas supply unit including: an anode gas supply line for supplying an anode gas to the electrical stack; an anode gas discharge line for receiving an anode gas discharged from the electrical stack; and a discharge valve provided on the anode gas discharge line; and a thermal management unit including: a coolant supply line for supplying a coolant to the electrical stack; a coolant discharge line for receiving a coolant discharged from the electrical stack; a first bypass branch connecting the coolant supply line and the coolant discharge line; and a heat exchanger provided on the first bypass branch, the heat exchanger being configured to allow the coolant to exchange heat with the discharge valve.

Description

Technical Field

[0001] This disclosure relates to the field of fuel cell technology, and more specifically, to a fuel cell system. Background Technology

[0002] Fuel cells have become one of the main power generation technologies due to their high power generation efficiency, low environmental pollution, and high specific energy. As a typical fuel cell, the proton exchange membrane fuel cell (PEMFC) is a popular type of fuel cell used in vehicles. PEMFCs generally consist of a solid polymer electrolyte proton exchange membrane, such as a perfluorosulfonic acid membrane. The anode and cathode typically comprise finely divided catalyst particles, usually platinum (Pt), supported on carbon particles and mixed with ionomers. The catalyst mixture is deposited on opposite sides of the membrane. The combination of the anode catalyst mixture, the cathode catalyst mixture, and the membrane defines the catalyst coating (CCM), while the catalyst coating and the two gas diffusion layers on either side define the membrane electrode assembly (MEA).

[0003] A fuel cell stack includes a series of bipolar plates positioned between several MEAs (Mechanical Exchange Assemblies) within the stack, with the bipolar plates and MEAs located between two end plates. Each bipolar plate includes an anode side and a cathode side for adjacent fuel cell units within the stack. An anode gas flow channel is provided on the anode side of the bipolar plate, allowing anode reactant gases to flow to the corresponding MEA. A cathode gas flow channel is provided on the cathode side of the bipolar plate, allowing cathode reactant gases to flow to the corresponding MEA. The anode and cathode gases flowing to both sides of the MEA diffuse to both sides of the proton exchange membrane and undergo an electrochemical reaction in the presence of a catalyst to generate electrical energy, while simultaneously producing water and heat as byproducts.

[0004] To prevent water flooding inside the fuel cell stack, the water needs to be drained along with the reactants. This means that in low-temperature environments, especially during cold starts, valves on the drain lines may freeze and fail to open, causing cold start failures. While existing technologies utilize resistance wires to heat the valves, the heating capacity of the resistance wires is limited and cannot effectively heat the valves, making it difficult to reliably prevent them from freezing.

[0005] Therefore, there is an urgent need in this field for a technical solution that can effectively heat the valves on the fuel cell stack discharge pipe to improve the success rate of fuel cell stack cold start. Utility Model Content

[0006] To address the problems in the prior art, this disclosure proposes an improved fuel cell system comprising: a fuel cell stack; an anode gas supply unit including: an anode gas supply line for supplying anode gas to the fuel cell stack; an anode gas discharge line for receiving anode gas discharged from the fuel cell stack; and a discharge valve disposed on the anode gas discharge line; and a thermal management unit including: a coolant supply line for supplying coolant to the fuel cell stack; a coolant discharge line for receiving coolant discharged from the fuel cell stack; a first bypass branch connecting the coolant supply line and the coolant discharge line; and a heat exchanger disposed on the first bypass branch, the heat exchanger being configured to allow heat exchange between the coolant and the discharge valve.

[0007] According to an optional embodiment of this disclosure, the thermal management unit further includes a radiator branch connecting the coolant supply line and the coolant discharge line, and a radiator disposed on the radiator branch.

[0008] According to an optional embodiment of this disclosure, the thermal management unit further includes a first reversing valve configured to allow coolant in the coolant discharge line to flow through the radiator branch or the first bypass branch to the coolant supply line.

[0009] According to an optional embodiment of this disclosure, the thermal management unit further includes a second bypass branch connecting the coolant supply line to the coolant discharge line.

[0010] According to an optional embodiment of this disclosure, the thermal management unit further includes a first reversing valve and a second reversing valve, the first reversing valve and the second reversing valve being configured to allow coolant in the coolant discharge line to flow through one of the radiator branch, the first bypass branch and the second bypass branch to the coolant supply line.

[0011] According to an optional embodiment of this disclosure, the thermal management unit further includes a third reversing valve configured to allow coolant in the coolant discharge line to flow through one of the radiator branch, the first bypass branch, and the second bypass branch to the coolant supply line.

[0012] According to an optional embodiment of this disclosure, the fuel cell stack includes an anode gas outlet for discharging anode gas, and the anode gas supply unit further includes a gas-liquid separator, the gas-liquid separator including an inlet connected to the anode gas outlet, a gas outlet connected to the anode gas supply line, and a liquid outlet connected to the anode gas discharge line.

[0013] According to an optional embodiment of this disclosure, the anode gas supply unit further includes an anode gas circulation pump disposed between the gas outlet of the gas-liquid separator and the anode gas supply pipeline.

[0014] According to an optional embodiment of this disclosure, the anode gas supply unit further includes a purge branch connecting the gas outlet of the gas-liquid separator to the anode gas discharge pipeline and a purge valve disposed on the purge branch, and the thermal management unit further includes an additional heat exchanger disposed on the first bypass branch, the additional heat exchanger being configured to allow heat exchange between the coolant and the purge valve.

[0015] According to an optional embodiment of this disclosure, the fuel cell stack includes an anode gas inlet for receiving anode gas, and the anode gas supply unit further includes: a hydrogen storage tank and an injector disposed on the anode gas supply line, the injector being in the form of a venturi tube and including a throat connected to the hydrogen storage tank and an outlet connected to the anode gas inlet; and an anode gas circulation pump disposed between the inlet of the injector and the anode gas discharge line.

[0016] This disclosure may be embodied in the illustrative embodiments shown in the accompanying drawings. However, it should be noted that the drawings are merely illustrative, and any variations contemplated under the teachings of this disclosure should be considered to be included within the scope of this disclosure. Attached Figure Description

[0017] The accompanying drawings illustrate exemplary embodiments of this disclosure. These drawings should not be construed as necessarily limiting the scope of this disclosure, wherein:

[0018] Figure 1 This is a schematic block diagram of a fuel cell system according to one embodiment of the present disclosure;

[0019] Figure 2 yes Figure 1 A schematic cross-sectional view of the exhaust valve and heat exchanger of the fuel cell system shown;

[0020] Figure 3 This is a schematic block diagram of a fuel cell system according to another embodiment of the present disclosure;

[0021] Figure 4 This is a schematic block diagram of a fuel cell system according to yet another embodiment of the present disclosure;

[0022] Figure 5 This is a schematic block diagram of a fuel cell system according to another embodiment of the present disclosure;

[0023] Figure 6This is a schematic block diagram of a fuel cell system according to yet another embodiment of the present disclosure; and

[0024] Figure 7 This is a schematic block diagram of a fuel cell system according to yet another embodiment of the present disclosure. Detailed Implementation

[0025] Further features and advantages of this disclosure will become more apparent from the following description with reference to the accompanying drawings. Exemplary embodiments of this disclosure are shown in the drawings, and the drawings are not necessarily drawn to scale. However, this disclosure can be implemented in many different forms and should not be construed as necessarily limited to the exemplary embodiments shown herein. Rather, these exemplary embodiments are provided merely to illustrate this disclosure and to convey the spirit and essence of this disclosure to those skilled in the art.

[0026] This disclosure aims to provide an improved fuel cell system. The novel design according to this disclosure significantly improves the success rate of cold start-up of the fuel cell system in low-temperature environments and reduces the additional energy consumption caused by cold start-up, thereby improving both the reliability and efficiency of the fuel cell system. In particular, the novel design according to this disclosure also significantly simplifies the system configuration and control logic of the fuel cell system, thereby reducing the configuration cost of the fuel cell system and further contributing to improved reliability.

[0027] Various alternative but non-limiting embodiments of the fuel cell system according to this disclosure are described in detail below with reference to the accompanying drawings. It should be noted that terms such as "connected" or "connected" as used in this disclosure refer to the existence of a path for fluid flow between two objects, and therefore their scope covers situations such as "directly connected" or "directly connected" as well as "indirectly connected" or "indirectly connected" between the two objects.

[0028] refer to Figure 1 A schematic block diagram of a fuel cell system according to one embodiment of the present disclosure is shown. Figure 1 As shown, the fuel cell system 10 generally includes a stack 100, a cathode gas supply unit 200, an anode gas supply unit 300, and a thermal management unit 400. The cathode gas supply unit 200 supplies cathode gas (e.g., air or other oxygen-containing gas) to the stack 100, and the anode gas supply unit 300 supplies anode gas (e.g., hydrogen or other hydrogen-containing gas) to the stack 100, so that the stack 100 can generate electrical energy through the electrochemical reaction of the cathode gas and the anode gas. The thermal management unit 400 dissipates the heat generated by the electrochemical reaction to prevent the stack 100 from overheating.

[0029] Specifically, the cathode gas supply unit 200 includes a cathode gas supply line 210 and a cathode gas discharge line 220 that are in fluid communication with the fuel cell stack 100. The cathode gas supply line 210 is connected to the cathode gas inlet 110 of the fuel cell stack 100, allowing the cathode gas to be supplied to the fuel cell stack 100 through the cathode gas inlet 110. The cathode gas discharge line 220 is connected to the cathode gas outlet 120 of the fuel cell stack 100, allowing the cathode gas to be discharged from the fuel cell stack 100 into the cathode gas discharge line 220 through the cathode gas outlet 120. Additionally, the cathode gas supply unit 200 includes a filter 211, a compressor 212, and a supply valve 213 disposed on the cathode gas supply line 210, and a discharge valve 221 disposed on the cathode gas discharge line 220. When the fuel cell stack 100 is running, after starting the compressor 212 and opening the supply valve 213 and discharge valve 221, the cathode gas supply line 210 can deliver air from the atmosphere, filtered by the filter 211, to the compressor 212. The compressed air from the compressor 212 is then delivered into the fuel cell stack 100 through the cathode gas inlet 110. The fuel cell stack 100 can discharge air through the cathode gas outlet 120 into the cathode gas discharge line 220, and then discharge the air into the atmosphere through the cathode gas discharge line 220. In this configuration, air can flow through the fuel cell stack 100, and the oxygen in the air can participate in the electrochemical reaction within the fuel cell stack 100 as a cathode gas, as described in detail below. Furthermore, by adjusting the speed of the drive motor of the compressor 212 and the opening degree of the supply valve 213 and discharge valve 221, the air pressure inside the fuel cell stack 100 can be changed, which helps to adjust the rate of the electrochemical reaction, thereby controlling the power output of the fuel cell stack 100. Specifically, since the air compressed by compressor 212 is high-temperature and dry, and the air discharged from fuel cell stack 100 often carries water generated by electrochemical reaction, in order to avoid the proton exchange membrane inside fuel cell stack 100 being dried out due to the supply of high-temperature and dry air to fuel cell stack 100, cathode gas supply unit 200 also includes humidifier 230. Humidifier 230 is installed on both cathode gas supply line 210 and cathode gas discharge line 220, and is configured to allow the air in cathode gas discharge line 220 to exchange moisture with the air in cathode gas supply line 210. Thus, the water generated by electrochemical reaction can be used to humidify the air supplied to fuel cell stack 100, thereby preventing the proton exchange membrane inside fuel cell stack 100 from drying out and reducing the output power of fuel cell stack 100.

[0030] The anode gas supply unit 300 includes an anode gas supply line 310 and an anode gas discharge line 320 in fluid communication with the fuel cell stack 100. The anode gas supply line 310 is connected to the anode gas inlet 130 of the fuel cell stack 100, allowing the anode gas to be supplied to the fuel cell stack 100 through the anode gas inlet 130. The anode gas discharge line 320 is connected to the anode gas outlet 140 of the fuel cell stack 100, allowing the anode gas to be discharged from the fuel cell stack 100 to the anode gas discharge line 320 through the anode gas outlet 140. Additionally, the anode gas supply unit 300 includes a hydrogen storage tank 311, a supply valve 312, and an injector 313 disposed on the anode gas supply line 310; a discharge valve 321 disposed on the anode gas discharge line 320; and an anode gas circulation pump 330 bridging the anode gas supply line 310 and the anode gas discharge line 320. When the fuel cell stack 100 is operating, after starting the anode gas circulation pump 330 and opening the supply valve 312 and discharge valve 321, the anode gas supply line 310 can deliver hydrogen from the hydrogen storage tank 311 to the ejector 313, and then deliver the hydrogen accelerated by the ejector 313 to the fuel cell stack 100 through the anode gas inlet 130. The fuel cell stack 100 can discharge anode gas into the anode gas discharge line 320 through the anode gas outlet 140, while the anode gas circulation pump 330 can deliver the hydrogen discharged from the fuel cell stack 100 to the anode gas supply line 310. This not only supplies fresh hydrogen to the fuel cell stack 100, but also recovers and reuses hydrogen that has not been consumed by the fuel cell stack 100. In this configuration, hydrogen can flow through the fuel cell stack 100 and can participate in electrochemical reactions within the fuel cell stack 100 as an anode gas, as described in detail below. In addition, by adjusting the speed of the drive motor of the anode gas circulation pump 330 and the valve opening of the supply valve 312 and the discharge valve 321, the hydrogen pressure inside the fuel cell stack 100 can be changed, which helps to adjust the rate of the electrochemical reaction and thus control the output power of the fuel cell stack 100.

[0031] The thermal management unit 400 includes a coolant supply line 410 and a coolant discharge line 420 in fluid communication with the fuel cell stack 100. The coolant supply line 410 is connected to the coolant inlet 150 of the fuel cell stack 100, allowing the coolant supply line 410 to supply coolant to the fuel cell stack 100 through the coolant inlet 150. The coolant discharge line 420 is connected to the coolant outlet 160 of the fuel cell stack 100, allowing the fuel cell stack 100 to discharge coolant into the coolant discharge line 420 through the coolant outlet 160. Additionally, the thermal management unit 400 includes a coolant circulation pump 421 installed on the coolant discharge line 420, a radiator branch 430 connecting the coolant supply line 410 and the coolant discharge line 420, and a radiator 431 installed on the radiator branch 430. When the fuel cell stack 100 is running, after the coolant circulation pump 421 is started, the coolant supply line 410 can deliver coolant to the fuel cell stack 100 through the coolant inlet 150, and the fuel cell stack 100 can discharge coolant to the coolant discharge line 420 through the coolant outlet 160. The radiator branch 430 can deliver coolant from the coolant discharge line 420 to the coolant supply line 410, and allow coolant to flow through the radiator 431. In this configuration, the coolant can circulate between the fuel cell stack 100 and the radiator 431 driven by the coolant circulation pump 421. Since the coolant can absorb the heat generated by the electrochemical reaction within the fuel cell stack 100 and dissipate it at the radiator 431, this configuration can ensure a uniform temperature distribution inside the fuel cell stack 100 to avoid localized hot spots, and can maintain the temperature inside the fuel cell stack 100 at a suitable temperature required for the electrochemical reaction to improve the efficiency of the electrochemical reaction.

[0032] Furthermore, after the cathode gas supply unit 200 supplies cathode gas (i.e., oxygen) to the fuel cell stack 100 and the anode gas supply unit 300 supplies anode gas (i.e., hydrogen) to the fuel cell stack 100, the cathode gas and anode gas diffuse into the cathode catalyst layer and anode catalyst layer on both sides of each proton exchange membrane, respectively, inside the fuel cell stack 100. At the anode catalyst layer, the anode gas decomposes into protons and electrons under the action of the catalyst material (i.e., undergoes an oxidation reaction: 2H₂→4H₂). + +4e - ), of which, proton (H + Electrons can pass through the proton exchange membrane to reach the cathode catalyst layer, but electrons (e) - Because it cannot pass through the proton exchange membrane, the gas can only reach the cathode catalyst layer through an external circuit. At the cathode catalyst layer, the cathode gas combines with protons and electrons under the action of the catalyst material to generate water (i.e., a reduction reaction occurs: O₂ + 4H₂O). + +4e -→2H2O). Through the above method, the fuel cell stack 100 can convert chemical energy into electrical energy through the electrochemical reaction (also known as a redox reaction) of the anode and cathode gases, thereby supplying power to the load on the external circuit, while simultaneously generating water and heat as byproducts. It is worth mentioning that although water is mainly generated at the cathode catalyst layer as mentioned above, it can also pass through the proton exchange membrane to reach the anode catalyst layer. Therefore, water is discharged from the fuel cell stack 100 not only with the cathode gas but also with the anode gas. This means that when the fuel cell system 10 operates in a low-temperature environment, especially during cold starts, the water may freeze and freeze or even block the discharge valve 321 on the anode gas discharge pipe 320. This will prevent the fuel cell stack 100 from draining and venting gas through the anode gas discharge pipe 320, resulting in a cold start failure of the fuel cell stack 100.

[0033] To ensure that fuel cell stack 100 can successfully cold start, such as Figure 1 As shown, the thermal management unit 400 also includes a first bypass branch 440 connecting the coolant supply line 410 and the coolant discharge line 420, and a heat exchanger 441 disposed on the first bypass branch 440. The first bypass branch 440 and the radiator branch 430 are connected in parallel between the coolant supply line 410 and the coolant discharge line 420. Therefore, the coolant in the coolant discharge line 420 can be selectively delivered to the coolant supply line 410 through the radiator branch 430 or the first bypass branch 440. The heat exchanger 441 is positioned at or adjacent to the discharge valve 321 so that the coolant in the heat exchanger 441 can exchange heat with the discharge valve 321. In this configuration, due to the presence of the first bypass branch 440, the coolant can circulate between the fuel cell stack 100 and the heat exchanger 441. Therefore, the coolant can absorb the heat generated by the electrochemical reaction within the fuel cell stack 100 and transfer this heat to the discharge valve 321 at the heat exchanger 441. This allows the heat generated by the electrochemical reaction to heat the discharge valve 321, preventing water in the discharge valve 321 from freezing or clogging in a low-temperature environment. This ensures that the fuel cell stack 100 can smoothly exhaust and drain gas through the anode gas discharge line 320 in a low-temperature environment, significantly improving the success rate of cold start-up of the fuel cell system in low-temperature environments. Furthermore, compared to the technical solution of heating the discharge valve 321 using a resistance wire, the configuration according to this disclosure not only heats the discharge valve 321 more effectively but also eliminates the need for additional power consumption. It also avoids increased configuration costs and complex control logic caused by resistance wires. Therefore, the configuration according to this disclosure can maintain the efficiency of the fuel cell system 10 while ensuring successful cold start-up, reducing configuration costs, and simplifying control logic.

[0034] like Figure 1 As shown, the thermal management unit 400 also includes a first directional valve 422 disposed on the coolant discharge line 420. The first directional valve 422 is a two-position three-way valve, having an inlet connected to the coolant discharge line 420, a first outlet connected to the first bypass branch 440, and a second outlet connected to the radiator branch 430. It also has a first valve position connecting the inlet to the first outlet and a second valve position connecting the inlet to the second outlet. Therefore, when the first directional valve 422 is in the first valve position, the coolant in the coolant discharge line 420 is delivered to the coolant supply line 410 through the first bypass branch 440, and when the first directional valve 422 is in the second valve position, the coolant in the coolant discharge line 420 is delivered to the coolant supply line 410 through the radiator branch 430. In this configuration, by switching the valve position of the first reversing valve 422, the coolant in the coolant discharge line 420 can be selectively delivered to the coolant supply line 410 via the radiator branch 430 or the first bypass branch 440. When the fuel cell system 10 is cold-started in a low-temperature environment, the coolant can flow through the heat exchanger 441 instead of the radiator 431, thereby maximizing the use of the heat generated by the electrochemical reaction to heat the discharge valve 321. After the fuel cell system 10 is successfully started, the coolant can flow through the radiator 431 instead of the heat exchanger 441, thereby helping the coolant dissipate heat efficiently and preventing overheating inside the fuel cell stack 100. It should be noted that although... Figure 1 A specific configuration of the fuel cell system 10 is shown, but this configuration is merely exemplary and not limiting. In other embodiments, the fuel cell system 10 may also be configured in other ways. For example, the coolant circulation pump 421 and the first reversing valve 422 may also be located on the coolant supply line 410, and the first reversing valve 422 may take the form of a valve other than a two-position three-way valve. Therefore, any configuration of the fuel cell system 10 under the teachings of this disclosure is within the scope of protection of this disclosure.

[0035] refer to Figure 2 , which shows Figure 1 The diagram shows a schematic cross-sectional view of the exhaust valve and heat exchanger of the fuel cell system. Figure 2As shown, the discharge valve 321 includes a valve body 321a defining a flow passage, a valve core (not shown) for controlling the opening and closing of the flow passage, and a drive assembly (e.g., including an armature and an electromagnetic coil) 321b for driving the valve core. The drive assembly 321b can drive the valve core according to a control signal to open or close the flow passage. When the valve core opens the flow passage, the fuel cell stack 100 can drain and exhaust gas through the anode gas discharge line 320. When the valve core closes the flow passage, the fuel cell stack 100 cannot drain and exhaust gas through the anode gas discharge line 320. Additionally, the heat exchanger 441 includes a coolant conduit 441a through which coolant flows. This coolant conduit 441a abuts against the valve body 321a of the discharge valve 321, allowing the coolant flowing in the coolant conduit 441a to exchange heat with the valve body 321a. This heat generated by the electrochemical reaction is used to heat the valve body 321a, preventing moving parts such as the armature and valve core from freezing or the flow channels from being blocked by ice. This ensures that the fuel cell system 10 can successfully cold-start in low-temperature environments. It should be noted that although... Figure 2 The illustration shows a specific configuration where the coolant conduit 441a is a straight conduit, but this is merely exemplary and not limiting. In other embodiments, the coolant conduit 441a may also be a curved conduit, such as a spiral conduit, arranged around the valve body 321a. Therefore, any configuration of the heat exchanger 441 under the teachings of this disclosure is within the scope of protection of this disclosure.

[0036] refer to Figure 3 A schematic block diagram of a fuel cell system according to another embodiment of the present disclosure is shown. Figure 3 The embodiments shown are the same as Figure 1The difference in the illustrated embodiment is that the thermal management unit 400 further includes a second bypass branch 450 connecting the coolant supply line 410 and the coolant discharge line 420. The second bypass branch 450, the first bypass branch 440, and the radiator branch 430 are connected in parallel between the coolant supply line 410 and the coolant discharge line 420. Therefore, the coolant in the coolant discharge line 420 can be selectively delivered to the coolant supply line 410 through one of the radiator branch 430, the first bypass branch 440, and the second bypass branch 450. Specifically, the thermal management unit 400 also includes a second directional valve 423 disposed on the coolant discharge line 420. This second directional valve 423 is also a two-position three-way valve, having an inlet connected to the coolant discharge line 420, a first outlet connected to the inlet of the first directional valve 422, and a second outlet connected to the second bypass branch 450. It also has a first valve position connecting the inlet to the first outlet and a second valve position connecting the inlet to the second outlet. Therefore, when the second directional valve 423 is in the first valve position, coolant in the coolant discharge line 420 is supplied to the inlet of the first directional valve 422, and when the first directional valve 422 is in the second valve position, coolant in the coolant discharge line 420 is supplied to the coolant supply line 410 through the second bypass branch 450. In this configuration, when the first directional valve 422 is in the first valve position and the second directional valve 423 is in the first valve position, the coolant in the coolant discharge line 420 is delivered to the coolant supply line 410 through the first bypass branch 440; when the first directional valve 422 is in the second valve position and the second directional valve 423 is in the first valve position, the coolant in the coolant discharge line 420 is delivered to the coolant supply line 410 through the radiator branch 430; and regardless of the valve position of the first directional valve 422, when the second directional valve 423 is in the second valve position, the coolant in the coolant discharge line 420 is delivered to the coolant supply line 410 through the second bypass branch 450. Therefore, through different valve position combinations of the first reversing valve 422 and the second reversing valve 423, the coolant in the coolant discharge line 420 can be selectively delivered to the coolant supply line 410 via one of the radiator branch 430, the first bypass branch 440, and the second bypass branch 450. When the fuel cell system 10 is cold-started in a low-temperature environment, the valve position combination that allows the coolant to flow through the second bypass branch 450 can be adopted first. Since there is no radiator or heat exchanger on the second bypass branch 450 to cool the coolant, the temperature of the coolant can rise rapidly. After the temperature of the coolant rises to the desired temperature, the valve position combination that allows the coolant to flow through the first bypass branch 440 can be adopted. This can more effectively heat the discharge valve 321, thereby more reliably ensuring that the fuel cell stack 100 can smoothly exhaust and drain gas through the anode gas discharge line 320 in a low-temperature environment.

[0037] It should be pointed out that, although Figure 3 A specific configuration is shown for changing the direction of coolant flow via two reversing valves located on the coolant discharge line 320, but this is merely exemplary and not limiting; other configurations may be used to change the direction of coolant flow in other embodiments. For example, one or both of the first reversing valve 422 and the second reversing valve 423 may be located on the coolant supply line 410. For another example, see reference... Figure 4 A schematic block diagram of a fuel cell system according to yet another embodiment of the present disclosure is shown. Figure 4 The embodiments shown are the same as Figure 3 The difference in the illustrated embodiment is that, instead of the first reversing valve 422 and the second reversing valve 423, the thermal management unit 400 includes a third reversing valve 424 disposed on the coolant discharge line 420. The third reversing valve 424 is in the form of a three-position four-way valve, having an inlet connected to the coolant discharge line 420, a first outlet connected to the first bypass branch 440, a second outlet connected to the second bypass branch 450, and a third outlet connected to the radiator branch 430. It also has a first valve position connecting the inlet to the first outlet, a second valve position connecting the inlet to the second outlet, and a third valve position connecting the inlet to the third outlet. In this configuration, when the third directional valve 424 is in the first position, the coolant in the coolant discharge line 420 is delivered to the coolant supply line 410 through the first bypass branch 440; when the third directional valve 424 is in the second position, the coolant in the coolant discharge line 420 is delivered to the coolant supply line 410 through the second bypass branch 450; and when the third directional valve 424 is in the third position, the coolant in the coolant discharge line 420 is delivered to the coolant supply line 410 through the radiator branch 430. Therefore, by switching the valve position of the third directional valve 424, the coolant in the coolant discharge line 420 can be selectively delivered to the coolant supply line 410 through one of the radiator branch 430, the first bypass branch 440, and the second bypass branch 450. When the fuel cell system 10 is cold-started in a low-temperature environment, the coolant can first be allowed to flow through the second valve position of the second bypass branch 450 to rapidly raise the temperature of the coolant. After the temperature of the coolant rises to the desired temperature, the coolant can be allowed to flow through the first valve position of the first bypass branch 440 to heat the discharge valve 321, thereby ensuring that the fuel cell stack 100 can exhaust and drain gas through the anode gas discharge line 320 in a low-temperature environment.

[0038] refer to Figure 5 A schematic block diagram of a fuel cell system according to another embodiment of the present disclosure is shown. Figure 5 The embodiments shown are the same as Figure 3The difference in the illustrated embodiment is that the anode gas supply unit further includes a gas-liquid separator 340 for separating the gas from the liquid. The gas-liquid separator 340 includes an inlet 341 connected to the anode gas outlet 140 of the fuel cell stack 100, a gas outlet 342 connected to the inlet of the anode gas circulation pump 330, and a liquid outlet 343 connected to the anode gas discharge line 320. In this configuration, the gas-liquid separator 340 can receive anode gas carrying water discharged from the anode gas outlet 140 of the fuel cell stack 100 through the inlet 341 and separate the anode gas from the water. Further, the gas-liquid separator 340 can discharge the anode gas through the gas outlet 342, while the anode gas circulation pump 330 can transport the anode gas discharged from the gas-liquid separator 340 to the anode gas supply line 310. The gas-liquid separator 340 can also discharge water through the liquid outlet 343, and the anode gas discharge line 320 can discharge the water discharged from the gas-liquid separator 340 into the atmosphere. Therefore, the above configuration, through the gas-liquid separator 340, prevents the anode gas circulation pump 330 from conveying water discharged from the fuel cell stack 100 to the anode gas supply line 310. This avoids interference and obstruction of the anode gas supplied to the fuel cell stack 100 by water, thereby ensuring the efficiency of the electrochemical reaction. Furthermore, it should be noted that the liquid outlet 343 of the gas-liquid separator 340 is not only used for drainage but also for venting. For example, after the gas-liquid separator 340 discharges water to the anode gas emission line 320 through the liquid outlet 343, the gas-liquid separator 340 can then discharge anode gas to the anode gas emission line 320 through the liquid outlet 343. Therefore, in this configuration, the anode gas emission line 320 is used for both drainage and venting from the anode side of the fuel cell stack 100, and a single emission valve 321 is sufficient to control both drainage and venting from the anode side of the fuel cell stack 100. This reduces the configuration cost of the fuel cell system 10 and simplifies its control logic.

[0039] certainly, Figure 5 The configuration shown, which controls drainage and venting via a single discharge valve 321, is merely exemplary and not limiting; separate valves could also be provided for drainage and venting on the anode side of the fuel cell stack 100. (Reference) Figure 6 The illustration shows a schematic block diagram of a fuel cell system according to yet another embodiment of the present disclosure. Figure 6 The embodiments shown are the same as Figure 5The difference in the illustrated embodiment is that the anode gas supply unit 300 further includes a purge branch 350 connecting the gas outlet 342 of the gas-liquid separator 340 to the anode gas discharge line 320 (specifically, the downstream portion of the discharge valve 321), and a purge valve 351 disposed on the purge branch 350. Additionally, the thermal management unit 400 includes an auxiliary heat exchanger 442 disposed on the first bypass branch 440, which is positioned at or adjacent to the purge valve 351, so that the coolant in the auxiliary heat exchanger 442 can exchange heat with the purge valve 351. In this configuration, the drainage and venting on the anode side of the fuel cell stack 100 can be controlled by the discharge valve 321 and the purge valve 351, respectively. For example, when it is necessary to purge the fuel cell stack 100 to discharge the anode gas, the purge valve 351 can be opened so that the purge branch 350 can transport the anode gas discharged from the gas-liquid separator 340 to the anode gas discharge pipeline 320, and then discharge the anode gas to the atmosphere through the anode gas discharge pipeline 320. The additional heat exchanger 442 can adopt a similar configuration to the heat exchanger 441 so as to use the heat generated by the electrochemical reaction to heat the purge valve 351, thereby preventing the purge valve 351 from freezing in the low temperature environment, so as to ensure that the fuel cell stack 100 can be smoothly vented through the purge branch 350.

[0040] refer to Figure 7 The diagram shows a schematic block diagram of a fuel cell system according to yet another embodiment of the present disclosure. Figure 7 The embodiments shown are the same as Figure 3 The difference in the illustrated embodiment is that the injector 313 is in the form of a venturi tube, having an inlet connected to the outlet of the anode gas circulation pump 330, an outlet connected to the anode gas inlet 130 of the fuel cell stack 100, and a throat connected to the anode gas supply line 310. In this configuration, the anode gas circulation pump 330 can deliver the anode gas discharged from the fuel cell stack 100 to the injector 313. When the anode gas flows through the throat of the injector 313, a low pressure is generated at the throat of the injector 313, thereby establishing a pressure difference between the throat of the injector 313 and the hydrogen storage tank 311. This pressure difference can drive the anode gas in the hydrogen storage tank 311 to the injector 313, so that the anode gas from the hydrogen storage tank 311 and the anode gas discharged from the fuel cell stack 100 can be mixed in the injector 313 and supplied to the fuel cell stack 100 by the injector 313. This eliminates the need for a separate gas pump to drive the anode gas in the hydrogen storage tank 311, thereby reducing the configuration cost of the fuel cell system 10 and simplifying its control logic.

[0041] The optional, but not limiting, embodiments of the fuel cell system according to this disclosure have been described in detail above with reference to the accompanying drawings. Modifications and additions to the technology and structure, as well as recombinations of features in the various embodiments, will be readily apparent to those skilled in the art without departing from the spirit and essence of this disclosure and should be considered within its scope. Therefore, all such modifications and additions conceivable under the teachings of this disclosure should be considered part of this disclosure. The scope of this disclosure includes equivalent technologies known at the filing date of this disclosure and equivalent technologies not yet foreseen.

Claims

1. A fuel cell system characterized by comprising: include: fuel cell stack (100); An anode gas supply unit (300) comprising: An anode gas supply line (310) for supplying anode gas to the fuel cell stack (100); An anode gas discharge line (320) for receiving anode gas discharged from the fuel cell stack (100); and A discharge valve (321) disposed on the anode gas discharge line (320); and a thermal management unit (400), the thermal management unit (400) comprising: Coolant supply line (410) for supplying coolant to the fuel cell stack (100); Coolant discharge line (420) for receiving coolant discharged from the fuel cell stack (100); A first bypass branch (440) connecting the coolant supply line (410) to the coolant discharge line (420); and A heat exchanger (441) is provided on the first bypass branch (440), the heat exchanger (441) being configured to allow the coolant to exchange heat with the discharge valve (321).

2. The fuel cell system of claim 1, wherein The thermal management unit (400) further includes a radiator branch (430) connecting the coolant supply line (410) and the coolant discharge line (420) and a radiator (431) disposed on the radiator branch (430).

3. The fuel cell system of claim 2, wherein The thermal management unit (400) further includes a first reversing valve (422) configured to allow coolant in the coolant discharge line (420) to flow through the radiator branch (430) or the first bypass branch (440) to the coolant supply line (410).

4. The fuel cell system of claim 2, wherein The thermal management unit (400) further includes a second bypass branch (450) connecting the coolant supply line (410) to the coolant discharge line (420).

5. The fuel cell system of claim 4, wherein The thermal management unit (400) further includes a first reversing valve (422) and a second reversing valve (423), the first reversing valve (422) and the second reversing valve (423) being configured to allow coolant in the coolant discharge line (420) to flow to the coolant supply line (410) through one of the radiator branch (430), the first bypass branch (440) and the second bypass branch (450).

6. The fuel cell system of claim 4, wherein The thermal management unit (400) further includes a third reversing valve (424) configured to allow coolant in the coolant discharge line (420) to flow to the coolant supply line (410) via one of the radiator branch (430), the first bypass branch (440), and the second bypass branch (450).

7. The fuel cell system according to any one of claims 1-6, characterized in that, The fuel cell stack (100) includes an anode gas outlet (140) for discharging anode gas, and the anode gas supply unit (300) further includes a gas-liquid separator (340) including an inlet (341) connected to the anode gas outlet (140), a gas outlet (342) connected to the anode gas supply line (310), and a liquid outlet (343) connected to the anode gas discharge line (320).

8. The fuel cell system of claim 7, wherein The anode gas supply unit (300) further includes an anode gas circulation pump (330) disposed between the gas outlet (342) of the gas-liquid separator (340) and the anode gas supply pipeline (310).

9. The fuel cell system of claim 7, wherein The anode gas supply unit (300) further includes a purge branch (350) connecting the gas outlet (342) of the gas-liquid separator (340) to the anode gas discharge line (320) and a purge valve (351) disposed on the purge branch (350). The thermal management unit (400) further includes an additional heat exchanger (442) disposed on the first bypass branch (440), the additional heat exchanger (442) being configured to allow the coolant to exchange heat with the purge valve (351).

10. The fuel cell system according to any one of claims 1 to 6, characterized by, The fuel cell stack (100) includes an anode gas inlet (130) for receiving anode gas, and the anode gas supply unit (300) further includes: A hydrogen storage tank (311) and an injector (313) are disposed on the anode gas supply line (310). The injector (313) is in the form of a venturi tube and includes a throat connected to the hydrogen storage tank (311) and an outlet connected to the anode gas inlet (130). An anode gas circulation pump (330) is installed between the inlet of the injector (313) and the anode gas discharge line (320).

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