fuel cell system

Abstract

This disclosure discloses a fuel cell system comprising: a fuel cell stack; an anode gas supply line for supplying anode gas to the fuel cell stack; an expander disposed on the anode gas supply line, the expander being configured to adiabatically expand the anode gas; 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 heat dissipation branch connecting the coolant supply line and the coolant discharge line; and a heat exchanger disposed on the heat dissipation branch, the heat exchanger also being disposed on the anode gas supply line and downstream of the expander, and configured to allow heat exchange between the coolant in the heat dissipation branch and the anode gas in the anode gas supply line.

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] If the heat generated by the electrochemical reaction cannot be effectively dissipated, the activity of the catalyst material, the lifespan of the proton exchange membrane, and other factors will be adversely affected by high temperatures. Therefore, thermal management of fuel cell stacks is one of the main factors restricting further improvement in stack power. However, in existing technologies, the cooling capacity of fuel cell thermal management systems is insufficient, especially when fuel cells are operating in hot weather. It is difficult to quickly dissipate the heat generated by the stack, thereby affecting the stack's operating efficiency and even leading to thermal runaway.

[0005] Therefore, there is an urgent need in this field for a technical solution that can reliably cool fuel cell stacks. 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 line for supplying anode gas to the fuel cell stack; an expander disposed on the anode gas supply line, the expander being configured to adiabatically expand the anode gas; 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 heat dissipation branch connecting the coolant supply line and the coolant discharge line; and a heat exchanger disposed on the heat dissipation branch, the heat exchanger also being disposed on the anode gas supply line and downstream of the expander, and configured to allow heat exchange between the coolant in the heat dissipation branch and the anode gas in the anode gas supply line.

[0007] According to an alternative embodiment of this disclosure, the heat exchanger is made of a thermally conductive material and is configured to contact both the anode gas supply line and the heat dissipation branch.

[0008] According to an alternative embodiment of this disclosure, the fuel cell system further includes a pressure regulating valve disposed on the anode gas supply line and located downstream of the expander, the pressure regulating valve being configured to control the pressure at the outlet of the expander.

[0009] According to one alternative embodiment of this disclosure, the pressure regulating valve is located downstream of the heat exchanger.

[0010] According to an alternative embodiment of this disclosure, the heat exchanger is disposed on a bend in the anode gas supply line and / or a bend in the heat dissipation branch.

[0011] According to an optional embodiment of the present disclosure, the fuel cell system further includes: an injector disposed on the anode gas supply line and located downstream of the expander; an anode gas discharge line for receiving anode gas discharged from the stack; and an anode gas recirculation line connecting the anode gas discharge line to the injector.

[0012] According to an alternative embodiment of this disclosure, the injector has a lumen extending from an inlet to an outlet, the lumen contracting from the inlet to a throat and expanding from the throat to the outlet, and the injector is provided with a second inlet leading to the throat.

[0013] According to an optional embodiment of this disclosure, the fuel cell system further includes an anode gas circulation pump disposed on the anode gas circulation pipeline, and the inlet and second inlet of the injector are respectively connected to the outlet of the anode gas circulation pump and the outlet of the expander.

[0014] According to an alternative embodiment of this disclosure, the expander has a lumen extending from an inlet to an outlet, the lumen contracting from the inlet to a throat and expanding from the throat to the outlet, and the inlet and second inlet of the injector are respectively connected to the outlet of the expander and the anode gas circulation pipeline.

[0015] According to an optional embodiment of this disclosure, the fuel cell system further includes a radiator disposed on the heat dissipation branch.

[0016] According to one alternative embodiment of this disclosure, the radiator is located downstream of the heat exchanger.

[0017] According to an optional embodiment of this disclosure, the fuel cell system further includes: a bypass branch connecting the coolant supply line and the coolant discharge line; and a reversing valve disposed on the coolant supply line or the coolant discharge line, the reversing valve being configured to select the cooling branch or the bypass branch to deliver coolant from the coolant discharge line to the coolant supply line.

[0018] 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

[0019] The accompanying drawings illustrate exemplary embodiments of this disclosure. These drawings should not be construed as necessarily limiting the scope of this disclosure, wherein:

[0020] Figure 1 This is a schematic block diagram of a fuel cell system according to one embodiment of the present disclosure;

[0021] Figure 2 yes Figure 1 A schematic cross-sectional view of the injector of the fuel cell system shown;

[0022] Figure 3 This is a schematic block diagram of a fuel cell system according to another embodiment of the present disclosure;

[0023] Figure 4 yes Figure 3 A schematic cross-sectional view of the expander of the fuel cell system shown;

[0024] Figure 5 This is a schematic block diagram of a fuel cell system according to yet another embodiment of the present disclosure; and

[0025] Figure 6 This is a schematic block diagram of a fuel cell system according to another embodiment of the present disclosure. Detailed Implementation

[0026] 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.

[0027] This disclosure aims to provide an improved fuel cell system. The fuel cell system according to this disclosure features a novel design that significantly improves the cooling capacity of the thermal management unit of the fuel cell system without requiring additional power consumption for this improved cooling capacity. This not only enables the fuel cell system to operate reliably in high-temperature weather conditions such as summer, but also improves the operating efficiency of the fuel cell system. In particular, the novel design according to this disclosure also significantly simplifies the system configuration of the fuel cell system, thereby reducing the configuration cost and simplifying its control logic, further improving the reliability of the fuel cell system.

[0028] 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" between two objects, as used in this disclosure, refer to the existence of a path for fluid flow between the two objects, and therefore their scope covers both the case of "direct connection" or "direct connection" between two objects without a third object between them and the case of "indirect connection" or "indirect connection" between them with a third object between them.

[0029] 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., oxygen 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.

[0030] 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 the discharge valve 221, the cathode gas supply line 210 can deliver air from the atmosphere and filtered by the filter 211 to the compressor 212. The air compressed by the compressor 212 is then delivered into the fuel cell stack 100 through the cathode gas inlet 110, so that the oxygen in the air can participate in the electrochemical reaction in the fuel cell stack 100 as cathode gas. After the electrochemical reaction, the fuel cell stack 100 can discharge the air that has consumed part of the oxygen 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.

[0031] The anode gas supply unit 300 includes an anode gas supply line 310 and an anode gas discharge line 320, which are 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, so that the anode gas supply line 310 can supply anode gas 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, so that the fuel cell stack 100 can discharge anode gas into the anode gas discharge line 320 through the anode gas outlet 140. In addition, the anode gas supply unit 300 also 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 line 330 connecting the injector 313 to the anode gas discharge line 320. When the fuel cell stack 100 is running, after opening the supply valve 312 and the 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, so that the hydrogen can participate in the electrochemical reaction in the fuel cell stack 100 as an anode gas. After the electrochemical reaction, the fuel cell stack 100 can discharge the unconsumed hydrogen to the anode gas discharge line 320 through the anode gas outlet 140, and the anode gas circulation line 330 can deliver the hydrogen in the anode gas discharge line 320 to the ejector 313. Thus, not only can fresh hydrogen be supplied to the fuel cell stack 100, but hydrogen that has not been consumed by the fuel cell stack 100 can also be recovered and reused.

[0032] 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 so that the coolant supply line 410 can 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 so that the fuel cell stack 100 can discharge coolant into the coolant discharge line 420 through the coolant outlet 160. In addition, the thermal management unit 400 also includes a coolant circulation pump 421 installed on the coolant discharge line 420 and a heat dissipation branch 430 connecting the coolant supply line 410 and the coolant discharge line 420. When the fuel cell stack 100 is running, after the coolant circulation pump 421 is started, the coolant supply line 410 can deliver low-temperature coolant to the fuel cell stack 100 through the coolant inlet 150, and the fuel cell stack 100 can discharge high-temperature coolant to the coolant discharge line 420 through the coolant outlet 160. Meanwhile, the heat dissipation branch 430 can deliver coolant from the coolant discharge line 420 to the coolant supply line 410 and cool the coolant from high temperature to low temperature during this process. This allows the coolant to circulate between the fuel cell stack 100 and the heat dissipation branch 430 under the drive of the coolant circulation pump 421, absorbing heat in the fuel cell stack 100 and dissipating heat on the heat dissipation branch 430.

[0033] 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, inside the fuel cell stack 100, the cathode gas and anode gas will convert chemical energy into electrical energy through an electrochemical reaction (also known as a redox reaction), thereby supplying power to the load on the external circuit. At the same time, water and heat are generated as byproducts. The water will be discharged into the cathode gas discharge pipe 220 along with the unconsumed cathode gas, while the heat will be absorbed by the coolant as it flows through the fuel cell stack 100 and dissipated as it flows through the heat dissipation branch 430. This can make the temperature distribution inside the fuel cell stack 100 uniform to avoid local hot spots, and can maintain the temperature inside the fuel cell stack 100 at the appropriate temperature required for the electrochemical reaction, so as to maintain the activity of the catalyst material and protect the proton exchange membrane from high temperature damage.

[0034] In order to effectively dissipate the heat of the coolant flowing through the heat dissipation branch 430, such as Figure 1As shown, the anode gas supply unit 300 also includes an expander 314 disposed on the anode gas supply pipeline 310. The expander 314 is located downstream of the hydrogen storage tank 311 and is configured to perform adiabatic expansion of the anode gas. That is, the expander 314 can receive hydrogen from the hydrogen storage tank 311, and the hydrogen can undergo adiabatic expansion within the expander 314. It is worth noting that, to maximize mechanical storage capacity, hydrogen is often stored in the hydrogen storage tank 311 at high pressures (e.g., 30 MPa-70 MPa or even higher). Therefore, the high-pressure hydrogen in the hydrogen storage tank 311 has high internal energy. The adiabatic expansion within the expander 314 can convert this internal energy of the high-pressure hydrogen into kinetic energy. Furthermore, during the adiabatic expansion process, not only does the hydrogen pressure decrease, but its temperature also decreases. For example, under ideal adiabatic conditions, theoretically, for every 10 MPa decrease in hydrogen pressure, its temperature can decrease by up to 55°C. Therefore, expander 314 can convert high-pressure hydrogen from hydrogen storage tank 311 into low-temperature hydrogen through adiabatic expansion. (Continue to reference...) Figure 1 The thermal management unit 400 also includes a heat exchanger 431 disposed on the heat dissipation branch 430. The heat exchanger 431 is also disposed on the anolyte gas supply line 310 and downstream of the expander 314, and is configured to allow heat exchange between the anolyte gas in the anolyte gas supply line 310 and the coolant in the heat dissipation branch 430. For example, the heat exchanger 431 may be made of a thermally conductive material (e.g., stainless steel, copper, copper alloy, etc.) and may be configured to contact both the anolyte gas supply line 310 and the heat dissipation branch 430.

[0035] In the above configuration, since the heat exchanger 431 is disposed on the heat dissipation branch 430, the coolant flowing in the heat dissipation branch 430 can transfer heat to the heat exchanger 431. Furthermore, since the heat exchanger 431 is also disposed on the anode gas supply line 310 and located downstream of the expander 314, the heat exchanger 431 can transfer heat to the low-temperature hydrogen gas discharged by the expander 314 and flowing in the anode gas supply line 310. This allows the low-temperature hydrogen gas discharged by the expander 314 to be used to cool the high-temperature coolant discharged by the fuel cell stack 100. Therefore, on the one hand, the above configuration can utilize the internal energy of the high-pressure hydrogen stored in the hydrogen storage tank 311 to cool the coolant, thereby improving the cooling capacity of the thermal management unit 400 without increasing additional power consumption. On the other hand, conversely, the high-temperature coolant discharged from the fuel cell stack 100 can be used to heat the low-temperature hydrogen discharged from the expander 314, thus preventing the low-temperature hydrogen discharged from the expander 314 from directly entering the fuel cell stack 100. This not only avoids excessive local temperature differences within the fuel cell stack 100 but also prevents the temperature of the fuel cell stack 100 from dropping below its suitable operating temperature, thereby helping to maintain and improve the operating efficiency of the fuel cell stack 100. It is also worth mentioning that since the expander 314 reduces the pressure of the hydrogen, there is no need to install an additional pressure-reducing device on the anode gas supply line 310. Therefore, the above configuration also helps to simplify the system configuration of the fuel cell system, thereby reducing the configuration cost of the fuel cell system and simplifying its control logic.

[0036] like Figure 1As shown, on the anode gas supply line 310, the supply valve 312 is arranged downstream of the expander 314 and is configured to control the pressure at the outlet of the expander 314. That is, the supply valve 312 can also be called the pressure regulating valve 312. Since the supply valve 312 is located downstream of the expander 314, the pressure at the outlet of the expander 314 can be controlled by adjusting the valve opening of the supply valve 312. As mentioned above, the temperature of hydrogen is related to its pressure. More specifically, within a certain range, the lower the pressure of hydrogen, the lower its temperature. Therefore, by controlling the pressure at the outlet of expander 314, the temperature of the hydrogen exchanging heat with the coolant at heat exchanger 431 can be regulated. This helps maintain the internal temperature of the fuel cell stack 100 at a suitable operating temperature. For example, when the fuel cell stack 100 has a high output power and generates a large amount of heat, the pressure at the outlet of expander 314 is reduced to lower the temperature of the hydrogen exchanging heat with the coolant, allowing the hydrogen to absorb more heat from the coolant and preventing the fuel cell stack 100 from overheating during high-power operation. Conversely, when the fuel cell stack 100 has a low output power and generates less heat, the pressure at the outlet of expander 314 is increased to raise the temperature of the hydrogen exchanging heat with the coolant, preventing the hydrogen from absorbing too much heat from the coolant and preventing the fuel cell stack 100 from overcooling during low-power operation. In particular, a supply valve 312 is also arranged downstream of heat exchanger 431 on the anode gas supply line 310. In this configuration, the cryogenic hydrogen discharged from the expander 314 will first flow through the heat exchanger 431 before flowing through the supply valve 312. In other words, the hydrogen flowing to the supply valve 312 has already absorbed heat from the coolant at the heat exchanger 431 and been heated up. This can prevent the cryogenic hydrogen from freezing the supply valve 312, which helps to improve the stability and reliability of the supply valve 312.

[0037] like Figure 1 As shown, the heat exchanger 431 is disposed on the bend 310a of the anode gas supply line 310, which has a serpentine (or meandering) shape. In this configuration, on the one hand, the bend 310a increases the contact area between the anode gas supply line 310 and the heat exchanger 431, thereby improving the heat exchange efficiency between hydrogen and coolant. On the other hand, the bend 310a further reduces the hydrogen pressure, thus acting as a pressure-reducing device to some extent. This prevents excessively high hydrogen pressure entering the fuel cell stack 100, which helps prevent hydrogen leakage to the cathode side within the fuel cell stack 100. Specifically, the heat exchanger 431 is also disposed on the bend 430a of the heat dissipation branch 430, which, similar to the bend 310a, also has a serpentine shape. In this configuration, the bend 430a increases the contact area between the heat dissipation branch 430 and the heat exchanger 431, which also helps improve the heat exchange efficiency between hydrogen and coolant.

[0038] refer to Figure 2 , which shows Figure 1 A schematic cross-sectional view of the injector in the fuel cell system shown. Figure 2 As shown, the ejector 313 has a lumen extending from an inlet 313i to an outlet 313o, the lumen first contracting and then expanding along the direction from the inlet 313i to the outlet 313o, and is particularly in the form of a Venturi tube. Specifically, the lumen of the ejector 313 has a throat 313t spaced apart from both the inlet 313i and the outlet 313o, a contracting section 313c extending from the inlet 313i to the throat 313t, and an expanding section 313e extending from the throat 313t to the outlet 313o, and the ejector 313 also has a second inlet 313s in fluid communication with the throat 313t. Figure 1 As shown, the anode gas supply unit 300 also includes an anode gas circulation pump 331 disposed on the anode gas circulation pipeline 330. The inlet of the anode gas circulation pump 331 is connected to the anode gas discharge pipeline 320, and its outlet is connected to the inlet 313i of the ejector 313. In addition, the outlet 313o of the ejector 313 is connected to the anode gas inlet 130 of the fuel cell stack 100, and its second inlet 313s is connected to the anode gas supply pipeline 310 (more specifically, the outlet of the expander 314). In this configuration, the anode gas circulation pump 331 can deliver hydrogen from the anode gas discharge line 320 to the inlet 313i of the injector 313 and drive the hydrogen to flow in the cavity of the injector 313. When the hydrogen flows through the throat 313t, the pressure drops due to the increased flow velocity, thereby generating a low pressure at the throat 313t. This low pressure can draw hydrogen from the anode gas supply line 310 to the throat 313t through the second inlet 313s, so that the hydrogen from the anode gas supply line 310 and the hydrogen from the anode gas discharge line 320 can be mixed in the cavity of the injector 313 and then delivered together to the fuel cell stack 100. In this configuration, the low pressure generated in the injector 313 by the hydrogen supplied by the anode gas circulation pump 331 can automatically draw the hydrogen in the anode gas supply line 310 into the injector 313 to mix it with the hydrogen from the anode gas discharge line 320. Since the hydrogen discharged from the fuel cell stack 100 is at a high temperature, the above mixing helps to adjust the temperature of the hydrogen to a suitable temperature before it is delivered to the fuel cell stack 100, which also helps to maintain the temperature inside the fuel cell stack 100 at a suitable operating temperature.

[0039] refer to Figure 3 and Figure 4 ,in, Figure 3 A schematic block diagram of a fuel cell system according to another embodiment of the present disclosure is shown, and Figure 4 It shows Figure 3 The diagram shows a schematic cross-sectional view of the expander of the fuel cell system. Figure 3 The embodiments shown are the same as Figure 1 The embodiments shown are largely the same, with the main difference being that the anode gas supply unit 300 has a different configuration. Specifically, as... Figure 4 As shown, the expander 314 has a lumen extending from an inlet 314i to an outlet 314o, which first contracts and then expands along the direction from the inlet 314i to the outlet 314o, and is particularly in the form of a Laval tube. Specifically, the lumen of the expander 314 has a throat 314t spaced apart from both the inlet 314i and the outlet 314o, a contraction section 314c extending from the inlet 314i to the throat 314t, and an expansion section 314e extending from the throat 314t to the outlet 314o. Figure 3 As shown, the inlet 314i of the expander 314 is connected to the hydrogen storage tank 311, and its outlet 314o is connected to the supply valve 312. Additionally, with... Figure 1 The embodiment shown differs in that the inlet 313i of the injector 313 is connected to the anode gas supply line 310 (more specifically, the outlet of the expander 314), and its second inlet 313s is connected to the anode gas circulation line 330. In this configuration, as the hydrogen flows through the cavity of the expander 314, it is accelerated by the cavity's guidance and undergoes adiabatic expansion in the expansion section 314e after flowing through the throat 314t. This increases the hydrogen's flow rate and decreases its pressure and temperature, thereby converting the hydrogen's internal energy into kinetic energy. Therefore, the above configuration allows the expander 314 to discharge low-temperature and high-speed hydrogen gas, which can absorb heat from the coolant as it flows through the heat exchanger 431 and then enter the ejector 313. When flowing in the cavity of the ejector 313, the hydrogen gas will generate a low pressure at the throat 313t. This low pressure can draw hydrogen gas from the anode gas discharge line 320 into the ejector 313 through the second inlet 313s and the anode gas circulation line 330, so that the hydrogen gas from the anode gas supply line 310 and the hydrogen gas from the anode gas discharge line 320 can be mixed in the ejector 313 and then transported together to the fuel cell stack 100. Therefore, under the above configuration, the low pressure generated in the injector 313 by the hydrogen discharged through the expander 314 can automatically draw the hydrogen in the anode gas discharge line 320 into the injector 313, thus eliminating the need to install an anode gas circulation pump 331 on the anode gas circulation line 330. Therefore, the above configuration helps to further simplify the system configuration of the fuel cell system, thereby reducing the configuration cost of the fuel cell system and simplifying its control logic.

[0040] refer to Figure 5 A schematic block diagram of a fuel cell system according to yet another embodiment of the present disclosure is shown. Figure 5 The embodiments shown are the same as Figure 3 The embodiments shown are largely the same, with the main difference being that the thermal management unit 400 has a different configuration. Specifically, as... Figure 5 As shown, the thermal management unit 400 also includes a radiator 432 disposed on the heat dissipation branch 430. The radiator 432 may include, for example, a fan that generates airflow and heat dissipation pipes through which coolant flows, and the coolant in the heat dissipation pipes can be cooled through heat exchange between the airflow and the heat dissipation pipes. In this configuration, the coolant undergoes two cooling processes at the heat exchanger 431 and the radiator 432. This allows the thermal management unit 400 to reduce the coolant temperature to the desired temperature through the heat exchanger 431 and the radiator 432 even if the coolant temperature discharged from the fuel cell stack 100 is high due to high power operation or operation in hot weather such as summer, thereby reliably preventing the fuel cell stack 100 from overheating. Therefore, the above configuration improves the cooling capacity of the thermal management unit 400. In particular, on the heat dissipation branch 430, the radiator 432 is arranged downstream of the heat exchanger 431, so that the coolant flows through the heat exchanger 431 first and then through the radiator 432. This configuration is advantageous because the coolant is cooled first at the heat exchanger 431 and then at the radiator 432. Since the coolant has already undergone cooling at the heat exchanger 431, the radiator 432 does not need to consume excessive power to lower the coolant to the desired temperature. Furthermore, since the heat exchanger 431 does not consume power to cool the coolant, the above configuration can reduce the power required to lower the coolant to the desired temperature, thereby improving the operating efficiency of the fuel cell system 10.

[0041] refer to Figure 6 A schematic block diagram of a fuel cell system according to another embodiment of the present disclosure is shown. Figure 6 The embodiments shown are the same as Figure 5 The embodiments shown are largely the same, with the main difference being that the thermal management unit 400 has a different configuration. Specifically, as... Figure 6As shown, the thermal management unit 400 also includes a bypass branch 440 connecting the coolant supply line 410 and the coolant discharge line 420. The bypass branch 440 and the heat dissipation branch 430 are connected in parallel between the coolant supply line 410 and the coolant discharge line 420. Therefore, coolant in the coolant discharge line 420 can be selectively supplied to the coolant supply line 410 via either the heat dissipation branch 430 or the bypass branch 440. Specifically, the thermal management unit 400 also includes a reversing valve 422 disposed on the coolant discharge line 420. This reversing 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 heat dissipation branch 430, and a second outlet connected to the bypass branch 440. 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. In this configuration, when the reversing 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 heat dissipation branch 430, and when the reversing 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 bypass branch 440. This configuration is advantageous because when the fuel cell system 10 undergoes a cold start in cold weather, such as winter, the reversing valve 422 can first be switched to the second position to allow coolant to flow through the bypass branch 440. Since the bypass branch 440 does not have a radiator or heat exchanger to cool the coolant, excessive heat loss from the fuel cell stack 100 can be avoided, which helps the temperature of the fuel cell stack 100 rise to a suitable operating temperature more quickly, thus achieving a rapid cold start. After the temperature of the fuel cell stack 100 rises to a suitable operating temperature, the reversing valve 422 can be switched to the first position to allow coolant to flow through the heat dissipation branch 430, thereby cooling the coolant through the heat dissipation branch 430 as described above, to prevent the fuel cell stack 100 from overheating. Therefore, the above configuration allows for both cold start and thermal management of the fuel cell stack 100. Of course, the above embodiment is merely exemplary, and the reversing valve 422 can also be installed on the coolant supply line 410.

[0042] 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 line (310) for supplying anode gas to the fuel cell stack (100); An expander (314) is provided on the anode gas supply line (310), the expander (314) being configured to adiabatically expand the anode gas; 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 heat dissipation branch (430) connecting the coolant supply line (410) to the coolant discharge line (420); and A heat exchanger (431) is disposed on the heat dissipation branch (430), and the heat exchanger (431) is also disposed on the anode gas supply line (310) and located downstream of the expander (314), and is configured to allow the coolant in the heat dissipation branch (430) to exchange heat with the anode gas in the anode gas supply line (310).

2. The fuel cell system of claim 1, wherein The heat exchanger (431) is made of a thermally conductive material and is configured to contact both the anode gas supply line (310) and the heat dissipation branch (430).

3. The fuel cell system according to claim 1 or 2, characterized by, The fuel cell system also includes a pressure regulating valve (312) disposed on the anode gas supply line (310) and located downstream of the expander (314), the pressure regulating valve (312) being configured to control the pressure at the outlet of the expander (314).

4. The fuel cell system of claim 3, wherein The pressure regulating valve (312) is located downstream of the heat exchanger (431).

5. The fuel cell system according to claim 1 or 2, characterized by The heat exchanger (431) is disposed on the bend (310a) of the anode gas supply line (310) and / or the bend (430a) of the heat dissipation branch (430).

6. The fuel cell system according to claim 1 or 2, characterized by The fuel cell system also includes: An injector (313) is installed on the anode gas supply line (310) and located downstream of the expander (314); An anode gas discharge line (320) for receiving anode gas discharged from the fuel cell stack (100); and The anode gas recirculation pipeline (330) connects the anode gas discharge pipeline (320) to the injector (313).

7. The fuel cell system according to claim 6, characterized in that, The injector (313) has a lumen extending from an inlet to an outlet, the lumen contracting from the inlet to a throat and expanding from the throat to the outlet, and the injector (313) is provided with a second inlet (313s) leading to the throat.

8. The fuel cell system of claim 7, wherein The fuel cell system also includes an anode gas circulation pump (331) disposed on the anode gas circulation pipeline (330), and the inlet and the second inlet (313s) of the injector (313) are respectively connected to the outlet of the anode gas circulation pump (331) and the outlet of the expander (314).

9. The fuel cell system of claim 7, wherein The expander (314) has a lumen extending from the inlet to the outlet, the lumen contracting from the inlet to the throat and expanding from the throat to the outlet, and the inlet and the second inlet (313s) of the injector (313) are respectively connected to the outlet of the expander (314) and the anode gas circulation line (330).

10. The fuel cell system according to claim 1 or 2, characterized by The fuel cell system also includes a radiator (432) disposed on the heat dissipation branch (430).

11. The fuel cell system of claim 10, wherein, The radiator (432) is located downstream of the heat exchanger (431).

12. The fuel cell system according to claim 1 or 2, characterized by The fuel cell system also includes: A bypass branch (440) connecting the coolant supply line (410) to the coolant discharge line (420); and A reversing valve (422) is provided on the coolant supply line (410) or the coolant discharge line (420), the reversing valve (422) being configured to select the heat dissipation branch (430) or the bypass branch (440) to deliver coolant from the coolant discharge line (420) to the coolant supply line (410).

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