Overvoltage protection device and fuel cell system

Abstract

The present invention belongs to the technical field of fuel cell system components and relates to an overpressure protection device and a fuel cell system. The overpressure protection device includes a housing, which is provided with an anode air inlet, a cathode air inlet, and an exhaust air outlet. The internal cavity of the housing is divided into a first cavity and a second cavity. A first elastic member and a reciprocating mechanism are provided in the first cavity. The end of the first elastic member away from the cathode air inlet is connected to the reciprocating mechanism, and the other end of the reciprocating mechanism is connected to a pressure relief valve located near the anode air inlet. The first elastic member is compressed in a first overpressure protection state, driving the reciprocating mechanism to move along the axis of the first elastic member toward the cathode air inlet, opening the pressure relief valve, and allowing anode gas flowing into the second cavity through the pressure relief valve to be discharged from the exhaust air outlet. The overpressure protection device can effectively protect the fuel cell stack and extend the service life of the fuel cell stack.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cell system components, and in particular to an overvoltage protection device and a fuel cell system. Background Art

[0002] A fuel cell stack is made up of many stacked single cells. The gas flow path inside the single cell is divided into two cavities: the cathode cavity and the anode cavity. The two cavities are separated by a membrane electrode. Hydrogen is introduced into the anode side and air into the cathode side. Through catalysis, the reverse reaction of water electrolysis is achieved, releasing electricity, water, and heat. However, due to the small thickness of the membrane electrode and its limited pressure resistance, when the pressure difference between the positive and negative electrodes is too large, the membrane electrode is easily damaged, resulting in gas leakage, that is, hydrogen leaking into the cathode cavity or air leaking into the anode cavity. In addition, there is also a maximum tolerable pressure between the positive and negative electrodes of the fuel cell stack and the external atmosphere. When the pressure inside the cavity exceeds the maximum tolerable pressure, gas leakage is likely to occur, that is, hydrogen or air inside the stack leaks into the external environment.

[0003] The anode working medium of a fuel cell system is hydrogen, which is stored in a high-pressure tank. When the fuel cell system is operating, the gas is released from the high-pressure tank, initially depressurized by a mechanical pressure reducing valve before entering the fuel cell system. The pressure is then further reduced by the hydrogen injection valve in the system, providing hydrogen that meets the operating pressure requirements of the stack. However, as the fuel cell system operates, the hydrogen in the anode cavity of the stack is continuously consumed, causing the internal pressure to drop. Therefore, it is necessary to control the anode-side gas pressure in real time to keep it within a reasonable range.

[0004] Currently, electrical control methods are generally used to control the anode side gas pressure in real time. That is, an anode pressure sensor is installed on the anode side. This anode pressure sensor monitors the pressure value on the anode side of the fuel cell stack in real time and provides real-time feedback to the control system. The control system dynamically controls the anode side gas pressure of the fuel cell stack through PID regulation to ensure that the anode side gas pressure is within a reasonable range. However, when the control system is in a faulty state or manually controlled, the anode cavity of the fuel cell stack will occasionally exceed the operating pressure, and even exceed the tolerance of the fuel cell system components, damaging the fuel cell system components and causing the fuel cell system to fail. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an overpressure protection device and a fuel cell system to address the technical problem that the membrane electrode of the fuel cell stack is easily damaged when the pressure difference in the existing fuel cell stack is too large.

[0006] To solve the above technical problems, an embodiment of the present invention provides an overpressure protection device, including a shell, on which an anode air inlet pipe port, a cathode air inlet pipe port and an exhaust pipe port are provided. The internal cavity of the shell is divided into a first cavity connected to the cathode air inlet pipe port and a second cavity connected to the anode air inlet pipe port. The first cavity and the second cavity are isolated from each other. A first elastic member and a reciprocating motion mechanism for controlling the air pressure difference between the anode and the cathode inside the fuel cell stack are provided inside the first cavity. The end of the first elastic member away from the cathode air inlet pipe port is connected to the reciprocating motion mechanism, and the other end of the reciprocating motion mechanism is connected to a pressure relief valve arranged near the anode air inlet pipe port.

[0007] Optionally, the reciprocating motion mechanism includes a piston body and a guide assembly, the cavity inside the piston body forms a piston cavity, and the guide assembly can be reciprocatingly arranged in the piston cavity; a second elastic member is provided between the piston body and the guide assembly for preventing the gas pressure on the anode side of the fuel cell stack from being too high.

[0008] Optionally, the housing includes a sealing member for forming a radial seal between the piston body and the housing, and the sealing member is sleeved on the piston body.

[0009] Optionally, the elastic coefficient of the second elastic member is greater than the elastic coefficient of the first elastic member.

[0010] Optionally, the first elastic member and the second elastic member are both springs.

[0011] Optionally, the pressure relief valve includes a valve core and a valve seat, and the valve core is connected to the reciprocating mechanism.

[0012] The valve core can move axially along the first elastic member or the second elastic member under the drive of the reciprocating motion mechanism, thereby being separated from or pressed against the valve seat to open or close the pressure relief valve.

[0013] Optionally, the guide assembly includes a movable part and a guide rod; the second elastic part is supported in the piston cavity through the movable part, and the guide rod is fixedly connected between the movable part and the valve core; the movable part is reciprocatingly arranged in the piston cavity.

[0014] The overpressure protection device provided by the embodiment of the present invention is provided with a first elastic member and a reciprocating motion mechanism inside the first cavity, so that the first elastic member is compressed when the pressure difference between the cathode and anode electrodes in the fuel cell stack exceeds the compression force of the first elastic member in the first overpressure protection state, driving the reciprocating motion mechanism to move along the axis of the first elastic member toward the cathode air inlet, opening the pressure relief valve, so that the anode gas flowing into the second cavity through the pressure relief valve is discharged from the exhaust pipe, thereby achieving the purpose of relieving the pressure of the anode side gas. While meeting the amount of gas required for the fuel cell stack reaction, the balance of the internal pressure difference of the fuel cell stack is controlled in real time according to the change of the internal pressure difference of the fuel cell stack, thereby effectively protecting the fuel cell stack and extending the service life of the fuel cell stack. In addition, the overpressure protection device provided by the embodiment of the present invention has a small number of components, a simple structure and low cost.

[0015] An embodiment of the present invention also provides a fuel cell system, including a fuel cell stack cathode cavity, a fuel cell stack anode cavity, and the overvoltage protection device, wherein the fuel cell stack cathode cavity is connected to the cathode air inlet pipe port in the overvoltage protection device, and the fuel cell stack anode cavity is connected to the anode air inlet pipe port in the overvoltage protection device.

[0016] The fuel cell system provided by the embodiments of the present invention, while meeting the gas volume required for the electric propulsion reaction within the system, can effectively maintain a balanced pressure differential within the fuel cell stack, guaranteeing the service life of the membrane electrode, and thus ensuring the stability of the fuel cell system. Furthermore, the anode-side gas pressure can be controlled within a certain range, effectively protecting the internal components of the fuel cell system and preventing gas leakage, thereby ensuring the safety of the fuel cell system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1. It is a specific structural diagram of an overvoltage protection device;

[0018] The reference numerals in the specification are as follows:

[0019] 1. Shell; 11. Anode air inlet; 12. Cathode air inlet; 13. Exhaust pipe; 2. First elastic member; 31. Valve seat; 32. Valve core; 4. Second elastic member; 51. Piston body; 52. Piston chamber; 531. Movable member; 532. Guide rod; 6. Sealing member. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] like Figure 1As shown, the overpressure protection device provided by an embodiment of the present invention includes a shell 1 and an anode air inlet pipe port 11, a cathode air inlet pipe port 12 and an exhaust pipe port 13 arranged on the shell 1. The internal cavity of the shell 1 is divided into a first cavity connected to the cathode air inlet pipe port 12 and a second cavity connected to the anode air inlet pipe port 11. A first elastic member 2 and a reciprocating motion mechanism are arranged inside the first cavity. One end of the first elastic member 2 away from the cathode air inlet pipe port 12 is connected to the reciprocating motion mechanism, and the other end of the reciprocating motion mechanism is connected to a pressure relief valve arranged near the anode air inlet pipe port 11; the first elastic member 2 is compressed in the first overpressure protection state, driving the reciprocating motion mechanism to move axially along the first elastic member 2 toward the cathode air inlet pipe port 12, opening the pressure relief valve, so that the anode gas flowing into the second cavity through the pressure relief valve is discharged from the exhaust pipe port 13.

[0022] This overpressure protection device can be used in fuel cell systems to ensure that, during operation, the pressure differential between the cathode and anode of the fuel cell stack is balanced, preventing damage to the stack's membrane electrode due to excessive internal pressure differentials. By separating the first and second cavities to form two sealed cavities, the first elastic member 2 is compressed or reset according to the pressure differential between the cathode and anode, thereby controlling the opening state of the pressure relief valve in real time.

[0023] To ensure the smooth reaction of the fuel cell stack, the cathode and anode of the fuel cell system must be fed with reactant gases, namely hydrogen and air, at a certain pressure and flow rate. The hydrogen and air introduced into the system, through a certain catalytic effect, achieve the reverse reaction of water electrolysis, releasing electricity, water, and heat. The anode inlet port 11 is used to receive hydrogen entering the anode cavity of the fuel cell stack, the cathode inlet port 12 is used to receive air entering the cathode cavity of the fuel cell stack, and the exhaust port 13 is used to discharge the anode gas flowing into the second cavity during overpressure protection.

[0024] Understandably, when the pressure differential between the cathode and anode of a fuel cell stack is too large, the membrane electrode can be easily damaged. Therefore, it is necessary to discharge the anode gas through the exhaust pipe 13 to reduce the anode side gas pressure and maintain a balanced pressure differential between the cathode and anode of the fuel cell stack, thereby effectively protecting the fuel cell stack and extending the service life of the fuel cell stack. The reciprocating mechanism can reciprocate along the axis of the first elastic member 2 under the drive of the first elastic member 2, and the pressure relief valve can be opened or closed according to the state of the anode side gas pressure.

[0025] Among them, when in the first overpressure protection state, the difference between the anode-side gas pressure and the cathode-side gas pressure is greater than the compression force of the first elastic member 2. Assuming that the cathode-side gas pressure is P1, the anode-side gas pressure is P2, and the compression force of the first elastic member 2 is F1, when P2-P1>F1, the anode-side gas pressure is too high, and the sum of the compression force F1 of the first elastic member 2 and the cathode-side gas pressure P1 is insufficient to balance the anode-side gas pressure P2. The first elastic member 2 is compressed, and drives the reciprocating motion mechanism to move along the axial direction of the first elastic member 2 toward the cathode gas inlet pipe port 12, so that the pressure relief valve opens, and the anode gas flowing into the second chamber through the pressure relief valve is discharged from the exhaust pipe port 13, achieving the purpose of relieving the anode-side gas pressure and making the pressure difference between the cathode and the cathode in a balanced state, thereby effectively protecting the fuel cell stack and extending the service life of the fuel cell stack.

[0026] Furthermore, when P2-P1≤F1, it is in a balanced state, the first elastic member 2 is reset, and drives the reciprocating motion mechanism to move along the axis of the first elastic member 2 toward the anode air inlet pipe 11, so that the pressure relief valve is closed under the drive of the reciprocating motion mechanism, so as to control the switching state of the pressure relief valve in real time according to the change of the pressure difference between the positive and negative poles in the fuel cell stack, thereby achieving the purpose of real-time pressure control.

[0027] The overpressure protection device provided by an embodiment of the present invention comprises a first elastic member 2 and a reciprocating mechanism disposed within a first cavity. This allows the first elastic member 2 to compress in a first overpressure protection state (i.e., when the pressure differential between the cathode and cathode electrodes within the fuel cell stack is excessive), driving the reciprocating mechanism to move axially along the first elastic member 2 toward the cathode inlet pipe port 12, thereby opening the pressure relief valve. This allows the anode gas flowing into the second cavity through the pressure relief valve to be discharged from the exhaust pipe port 13, thereby relieving the pressure of the anode-side gas. This balance of the pressure differential between the cathode and cathode electrodes within the fuel cell stack is controlled in real time based on changes in the pressure differential between the cathode and cathode electrodes, thereby ensuring the safety and stability of the fuel cell stack. Furthermore, the overpressure protection device provided by an embodiment of the present invention has a small number of components, a simple structure, and low cost.

[0028] In one embodiment, if Figure 1 As shown, the reciprocating motion mechanism includes a piston body 51 and a guide assembly, a piston cavity 52 is provided inside the piston body 51, and the guide assembly can be reciprocatingly arranged in the piston cavity 52; a second elastic member 4 is provided between the piston body 51 and the guide assembly; the second elastic member 4 is compressed in the second overpressure protection state, driving the guide assembly to move along the axial direction of the second elastic member 4 toward the cathode air inlet pipe port 12, opening the pressure relief valve, so that the anode gas flowing into the second cavity through the pressure relief valve is discharged from the exhaust pipe port 13.

[0029] In this embodiment, by controlling the compression of the second elastic member 4 in the second overpressure protection state, the guiding component is driven to move along the axis of the second elastic member 4 towards the cathode inlet pipe port 12, opening the pressure relief valve, so that the anode gas flowing into the second cavity through the pressure relief valve is discharged from the exhaust pipe port 13, which can effectively prevent the further increase of the gas pressure on the anode side, and avoid the problem that when the control system is in a fault state during the pressure control by the electric control method, the sudden increase of the gas pressure on the anode side may cause damage to the system components.

[0030] In addition, since the anode gas is hydrogen, and hydrogen is a flammable and explosive gas, once leaked, it is easy to cause safety problems. By controlling the gas pressure on the anode side, it can also effectively prevent the leakage of the anode gas (i.e., hydrogen), improving the safety of the fuel system.

[0031] Among them, when the difference between the gas pressure on the anode side and the gas pressure on the cathode side is less than the compression force of the first elastic member 2, the gas pressure on the cathode side and the gas pressure on the anode side are increased. When the gas pressure on the anode side is greater than the compression force of the second elastic member 4, the fuel cell stack is in the second overpressure protection state. It can be understood that assuming the gas pressure on the cathode side is P1, the gas pressure on the anode side is P2, the compression force of the first elastic member 2 is F1, and the compression force of the second elastic member 4 is F2. When P2 - P1 < F1, the pressure difference between the anode and cathode inside the fuel cell stack is in a balanced state at this time, and the reciprocating motion mechanism will not move along the spring axis. At this time, as the reaction in the fuel cell stack proceeds, hydrogen and air are continuously introduced, and the gas pressure on the cathode side and the gas pressure on the anode side continue to increase. When the gas pressure on the anode side is greater than the compression force of the second elastic member 4 (i.e., P2 > F2), it is in the second overpressure protection state at this time, and the second elastic member 4 compresses to drive the guiding component to move along the axis of the second elastic member 4 towards the cathode inlet pipe port 12, opening the pressure relief valve, so that the anode gas flowing into the second cavity through the pressure relief valve is discharged from the exhaust pipe port 13, timely reducing the gas pressure on the anode side to make the gas pressure on the anode side within the compression force of the second elastic member 4, effectively solving the problem that the gas pressure on the anode side exceeds the tolerance of the components and easily damages the system components. In addition, it can also prevent the leakage of the gas on the anode side and improve safety.

[0032] Further, after the pressure relief of the anode side gas, when P2 ≤ F2, it is in a balanced state at this time, then the second elastic member 4 resets, driving the guiding component to move along the axis of the second elastic member 4 towards the anode inlet pipe port 11, so that the pressure relief valve is closed under the drive of the guiding component, to control the opening and closing state of the pressure relief valve in real time according to the change of the anode side gas pressure, achieving the purpose of real-time pressure control.

[0033] It should be noted that the compressive force of the first elastic member 2 and the compressive force of the second elastic member 4 can be adjusted according to actual needs and are not limited here. It is understandable that by adjusting the compressive force of the first elastic member 2 and the compressive force of the second elastic member 4, different pressure control requirements can be met, making the overvoltage protection device provided in this embodiment highly versatile and applicable to different pressure control scenarios.

[0034] It can be understood that the compression force of the first elastic member 2 and the compression force of the second elastic member in this embodiment can be regarded as two opening thresholds for opening the pressure relief valve, so as to achieve the purpose of two-level pressure relief.

[0035] The overpressure protection device provided in this embodiment utilizes a mechanically controlled pressure relief valve that opens in either the first or second overpressure protection state to achieve a two-stage pressure relief. This effectively balances the pressure differential between the cathode and anode electrodes while preventing anode-side gas pressure from rising beyond the tolerances of fuel cell system components and potentially damaging them, thereby ensuring the safety and stability of the fuel cell system. Furthermore, it effectively prevents damage to system components caused by sudden anode-side gas pressure fluctuations when the control system fails, as is the case with electronically controlled pressure control.

[0036] In one embodiment, if Figure 1 As shown, the housing 1 includes a seal 6, which is sleeved on the piston body 51 and is used to form a radial seal between the piston body 51 and the inner wall of the housing 1. By forming a radial seal between the piston body 51 and the interior of the housing 1, the first cavity and the second cavity are isolated from each other, avoiding the problem of the internal pressure difference of the fuel cell stack being unable to be controlled according to the pressure balance principle due to the connection between the two cavities.

[0037] In one embodiment, the elastic coefficient of the second elastic member 4 is greater than the elastic coefficient of the first elastic member 2 .

[0038] It is understood that the elastic coefficient of the second elastic member 4 needs to be greater than the elastic coefficient of the first elastic member 2 so that, in the first overpressure protection state, i.e., when the pressure differential between the cathode and anode electrodes in the fuel cell stack is greater than the compressive force of the first elastic member 2, the pressure relief valve can be opened by the compression of the first elastic member 2 to release the anode-side gas, thereby achieving the purpose of primary pressure relief. Simultaneously, in the second overpressure protection state, i.e., when the pressure differential between the cathode and anode electrodes in the fuel cell stack is in a balanced state and the anode-side gas pressure is excessive, exceeding the compressive force of the second elastic member 4, the pressure relief valve can be opened by the compression of the second elastic member 4 to release the anode-side gas, thereby achieving the purpose of secondary pressure relief. This ensures that the pressure differential between the cathode and anode electrodes in the fuel cell stack is in a balanced state and that the anode-side gas pressure is within the compressive force of the second elastic member 4, thereby preventing the anode-side gas pressure from being too high and damaging the fuel cell system components, and effectively ensuring the safety and stability of the fuel cell system.

[0039] In one embodiment, the first elastic member 2 and the second elastic member 4 are both springs. The first elastic member 2 and the second elastic member 4 are coil springs, which are light in weight, small in space and low in cost.

[0040] In one embodiment, the pressure relief valve includes a valve core 32 and a valve seat 31, and the valve core 32 is connected to a reciprocating motion mechanism; the reciprocating motion mechanism drives the valve core 32 to move axially along the first elastic member 2 or the second elastic member 4, separating from the valve seat 31 to open the pressure relief valve.

[0041] The valve seat 31 is used to support the fully closed position of the valve core 32 and form a sealing pair. The valve body realizes basic functions such as direction control, pressure control or flow control by means of the movement of the valve core 32.

[0042] In this embodiment, when the pressure difference between the positive and negative poles in the fuel cell stack is greater than the compression force of the first elastic member 2, that is, when it is in the first overpressure protection state, the first elastic member 2 is compressed and drives the reciprocating motion mechanism to move along the axial direction of the first elastic member 2 toward the cathode air inlet pipe port 12, thereby driving the valve core 32 to move along the first elastic member 2 toward the cathode air inlet pipe port 12 and separate from the valve seat 31 to open the pressure relief valve and relieve the pressure of the anode side gas.

[0043] When the gas pressure on the anode side is greater than the compression force of the second elastic member 4, that is, when it is in the second overpressure protection state, the second elastic member 4 is compressed toward the cathode air inlet pipe port 12, driving the movable member 531 to move in the piston chamber 52, thereby driving the valve core 32 to move toward the cathode air inlet pipe port 12 through the reciprocating motion mechanism, so that the valve core 32 is separated from the valve seat 31 to release the gas pressure on the anode side.

[0044] After the anode side gas is depressurized, the anode side gas pressure decreases. At this time, the pressure difference between the positive and negative electrodes in the fuel cell stack is in a balanced state. The first elastic member 2 is compressed toward the anode air inlet pipe port 11, driving the reciprocating motion mechanism to move toward the anode air inlet pipe port 11, so that the valve core 32 is pressed against the valve seat 31, and the balanced state is restored.

[0045] Alternatively, when the pressure difference between the positive and negative electrodes in the fuel cell stack is in a balanced state and the gas pressure on the anode side does not exceed the compression force of the second elastic member 4, the second elastic member 4 is compressed toward the anode air inlet pipe port 11, driving the reciprocating motion mechanism to move toward the anode air inlet pipe port 11, so that the valve core 32 is pressed against the valve seat 31, and the balanced state is restored.

[0046] In one embodiment, if Figure 1As shown, the guide assembly includes a movable member 531 and a guide rod 532; the second elastic member 4 is supported in the piston body 51 through the movable member 531, and the guide rod 532 is fixedly connected between the movable member 531 and the valve core 32; the movable member 531 is reciprocatingly arranged in the piston cavity 52.

[0047] In this embodiment, when the anode-side gas pressure is in the second overpressure protection state (i.e., when the anode-side gas pressure is greater than the compressive force of the second elastic member 4), the second elastic member 4 compresses toward the cathode inlet port 12, driving the movable member 531 to move within the piston chamber 52. This, in turn, drives the valve core 32 toward the cathode inlet port 12 via the guide rod 532, causing the valve core 32 to separate from the valve seat 31. Anode gas flows into the second chamber and is discharged through the exhaust port 13 provided therein, preventing further increases in anode-side gas pressure that could damage fuel cell system components. Furthermore, this effectively prevents safety hazards caused by increased anode-side gas pressure, such as gas leakage, thereby effectively improving the safety and stability of the fuel cell system.

[0048] After the anode side gas pressure is released, the anode side gas pressure decreases. When the anode side gas pressure is less than the compression force of the second elastic member 4, the second elastic member 4 is compressed toward the anode air inlet pipe port 11, driving the movable member 531 to move in the piston chamber 52, thereby driving the valve core 32 to move toward the anode air inlet pipe port 11 through the guide rod 532, so that the valve core 32 is pressed against the valve seat 31 and the equilibrium state is restored. The switching state of the pressure relief valve is controlled in real time according to the change of the anode side gas pressure based on the pressure balance principle to achieve the purpose of real-time pressure control.

[0049] In one embodiment, when the first elastic member 2 and the second elastic member 4 are in a non-overpressure protection state, they press the valve core 32 onto the valve seat 31 , so that the pressure relief valve is in a closed state.

[0050] Among them, the non-overpressure protection state refers to a state other than the first overpressure protection state and the second overpressure protection state. It can be understood that the non-overpressure protection state may include a state in which the pressure difference between the positive and negative poles in the fuel cell stack is not greater than the compression force of the first elastic member 2, and a state in which the pressure difference between the positive and negative poles in the fuel cell stack is not greater than the compression force of the first elastic member 2 and the anode side gas pressure is not greater than the compression force of the second elastic member 4.

[0051] Specifically, when in the non-overpressure protection state, the valve core 32 is pressed onto the valve seat 31 by the pre-tightening force of the first elastic member 2 and the second elastic member 4, so that the pressure relief valve is in a closed state, forming a sealing surface, maintaining the balance of the internal pressure difference of the fuel cell stack, and not being affected by the external environment.

[0052] An embodiment of the present invention also provides a fuel cell system, including a fuel cell stack cathode cavity, a fuel cell stack anode cavity and the overvoltage protection device of the above embodiment, the fuel cell stack cathode cavity is connected to the cathode air inlet pipe port 12 in the overvoltage protection device, and the fuel cell stack anode cavity is connected to the anode air inlet pipe port 11 in the overvoltage protection device.

[0053] The fuel cell system includes an anode gas supply subsystem and a cathode gas supply subsystem. The anode gas supply subsystem is used to supply hydrogen into the anode cavity of the fuel cell stack in the system, while the cathode gas supply subsystem is used to supply air into the cathode cavity of the fuel cell stack in the system.

[0054] Specifically, the cathode cavity of the fuel cell stack is connected to the cathode air inlet port 12 in the overpressure protection device, and the anode cavity of the fuel cell stack is connected to the anode air inlet port 11 in the overpressure protection device, so that the mechanically controlled pressure relief valve inside the fuel cell system is opened in the first overpressure protection state or the second overpressure protection state to achieve the purpose of secondary pressure relief. It can effectively control the pressure difference in the fuel cell stack to be in a balanced state, and can also control the gas pressure on the anode side to be within the compression force of the second elastic member 4, thereby effectively ensuring the safety and stability of the fuel cell system.

[0055] The fuel cell system provided by the embodiments of the present invention, while meeting the gas requirements for the cell stack reaction within the system, can effectively maintain a balanced pressure differential within the fuel cell stack, guaranteeing the service life of the membrane electrode, and thus ensuring the stability of the fuel cell system. Furthermore, the anode-side gas pressure can be controlled to be within the compressive force of the second elastic member 4, effectively protecting the internal components of the fuel cell system and preventing gas leakage, thereby ensuring the safety of the fuel cell system.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An overvoltage protection device, characterized in that: The fuel cell stack comprises a housing provided with an anode air inlet, a cathode air inlet, and an exhaust air inlet. The housing comprises an internal cavity divided into a first cavity communicating with the cathode air inlet and a second cavity communicating with the anode air inlet. The first cavity and the second cavity are isolated from each other. A first elastic member and a reciprocating mechanism for controlling the pressure difference between the anode and cathode in the fuel cell stack are provided inside the first cavity. One end of the first elastic member away from the cathode air inlet is connected to the reciprocating mechanism, and the other end of the reciprocating mechanism is connected to a pressure relief valve provided near the anode air inlet. The reciprocating mechanism includes a piston body and a guide assembly. The cavity inside the piston body forms a piston cavity. The guide assembly is reciprocatingly arranged in the piston cavity. A second elastic member is provided between the piston body and the guide assembly to prevent excessive gas pressure on the anode side of the fuel cell stack. When the anode side gas pressure is greater than the compression force of the second elastic member, the second elastic member compresses, driving the guide assembly to move along the axis of the second elastic member toward the cathode air inlet pipe, opening the pressure relief valve and reducing the anode side gas pressure.

2. The overvoltage protection device according to claim 1, characterized in that: The housing includes a sealing member for forming a radial seal between the piston body and the housing, and the sealing member is sleeved on the piston body.

3. The overvoltage protection device according to claim 1, characterized in that: The elastic coefficient of the second elastic member is greater than the elastic coefficient of the first elastic member.

4. The overvoltage protection device according to claim 1, characterized in that: The first elastic member and the second elastic member are both springs.

5. The overvoltage protection device according to claim 1, characterized in that: The pressure relief valve includes a valve core and a valve seat. The valve core is connected to the reciprocating motion mechanism. The valve core can move axially along the first elastic member or the second elastic member under the drive of the reciprocating motion mechanism, thereby separating from or pressing the valve seat to open or close the pressure relief valve.

6. The overvoltage protection device according to claim 5, characterized in that: The guide assembly includes a movable member and a guide rod; the second elastic member is supported in the piston cavity through the movable member, and the guide rod is fixedly connected between the movable member and the valve core; the movable member is reciprocatingly arranged in the piston cavity.

7. A fuel cell system, characterized in that: It comprises a battery stack cathode cavity, a battery stack anode cavity, and the overvoltage protection device according to any one of claims 1 to 6, wherein the battery stack cathode cavity is connected to the cathode air inlet pipe in the overvoltage protection device, and the battery stack anode cavity is connected to the anode air inlet pipe in the overvoltage protection device.

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